Alternative Feedstocks Program

Technical and Economic Assessment

Thermal/Chemical and Bioprocessing

Components .

Prepared for

The Do S.. Department of Energy

Office of Industrial Technologies

by

Argonne National Laboratory

Idaho National Engineering Laboratory

National Renewable Energy Laboratory

Oak Ridge National Laboratory

Pacific Northwest Laboratory

Joseph J.. Bozell

Ron Landucci

Editors
DISCLAIMER

nus report was prepared as an account of work sponsored by an agency of the United States

Government. Neither the United States Government n OT any agency thereof, nOT any of their

employees.. makes any warrantyr expressed or implied, or assumes any legal liability or responsibility

for the accuracy, completenessr or usefulness of any information, apparatus, product, or process

disclosed, or represents that its use would not infringe privately owned rights.

Reference herein to any specific commercial product, process, or service by trade name, trademark,

manufacturer, or otherwise, does not necessarily constitute orimply its endorsement, recommendation.. or

favoring by me United States Government or any agency thereof. The views and opinions of authors

expressed herein do not necessartly state or reflect those of the United States Government or any agency

thereof.

This report ascribes research to the United States Department of Agriculture (USDA} but does not

attempt to provide a comprehensive review of all USDA work. In addition, land use data may not

reflect updated information available from the USDA. The reader is referred to USDA offices for more

complete information.
-. ' ":.

Acknowledgements

We hope that this document will be a valuable resource to help interested individuals in academia,

industry, and government identify promising opportunities for producing chemicals from alternative

feedstocks. This document isthe result of the hard work of many individuals at the Departments of

Agriculture and Energy, and the National Laboratories that make up the National Laboratory Team

for Alternative Feedstocks. However, to paraphrase one of the reviewers, "national labs do not write

documents, people write documents." We would like to thank the following individuals at the

National Laboratories and the Departments of Agriculture and Energy for a true team effort in

assembling this report.

Argonne National Laboratory: Jim Frank, Rathin Datta, Shih-Pemg Tsai, Mark Donnelly, SeungHyeon Moon, Jo Ann Parnell, Marianne Schiffer, Satya Kakar, Fred Stevens, Deborah Hanson, Norm

Sather, Christopher Reilly, Patrick Bonsignore, and Cynthia Sanville-Millard.

Idaho National Engineering Laboratory: Kevin Polman, Debonny Shoaf, Lynn Apel, Robert Bumbary,

Gene A. Giesbrecht, Graham F. Andrews, Elmer H. Fleischman, Gregory A. Bala, Jack Prendergast and

Joseph G. Keller.

National Renewable Energy Laboratory: Barb Goodman, Arthur J. Power (NREL subcontractor and

president of Arthur J. Power and Associates), Mark Finkelstein, Steve Kelley and Foster Agblevor.

Oak Ridge National Laboratory: Brian H. Davison, Timothy C. Scott,}. W. Ranney, and LYnnWright.

Pacific Northwest Laboratory: Douglas C. Elliott and David E. Eakin.

United States Department of Agriculture: Hosein Shapouri, Douglas Beach, W. Lamar Harris, and

Rich Greene.

United States Department of Energy: linda Beth Schilling, Daniel E. Wiley, David J. Boron, Clement

Yonker, Gregory Dilworth, Gesina C. Carter, Oscar Manley, Leonard Keay, and Patricia St. Clair.

We would also like to thank the laboratory team coordinator, Gene Petersen CNREL), and the resource

management team, Helena Chum (NREL), LaMar Johnson (INEL), Bill Schertz (ANL), Chuck Scott

(ORNL), John Sealock <PNL), and Charlie Wyman <NREL), for their continuing support, input, and

advice.

Joseph J. Bozell

Ron Landucci

National Renewable Energy Laboratory

Editors

July, 1993

1
TABLE OF CONTENTS

EXECUTIVE SUMMARY .

Report Overview .

Introduction .

Overview of the Technoeconomic Evaluation of Proposed Process Routes

from Renewables 14

Overview of Technoeconomic Evaluation of Thermal and

Chemical Processes 14

Overview of Technoeconomic Evaluation of Biological

Processes 15

Improving the Evaluation Process 15

Recommendation Overview . . . . . . . . . . . . . . . . 15

Thermal and Chemical Recommendations _. . . . . . . . . . . . . . . . 15

Bioprocessing Recommendations 16

Developmental Process for Recommended Products and Processes 16

Near Term RD&D Opportunities _. . . . .. 17

Mid Term RD&D Opportunities 18

Long Term RD&D Opportunities 18

Related RD&D Opportunities 19

OVERVIEW OF FACTORS CONTRIBUTING TO ANALySIS...................... 21

Energy- Considerations _. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

Environmental Considerations 24

Legislative Considerations 25

Chemical Industries 25

Pulp, Paper and Paperboard Industries 'Z7

Windows of Opportunity _ . . . . . . . . . . . . . . . .. 28

Example - Biodegradable Polymers 28

Example - Fast Pyrolysis of Biomass 28

Example - Bioprocessing of Renewables 29

Examples - Technical Advances and New Applications 29

Overview of Key Industrial Sectors 31

The Chemical Industry 31

The Petrochemical Industry 33

The Renewables Industry 36

Chemicals and Materials Currently Produced from Alternative

Feedstocks 37

Integrated Processing 37

Use of a Specific Crop for Producing Industrial Chemicals and

Materials 37

AVAILABIUTY, USE, AND COMPOSmON OF BIOMASS 41

General Overview. . . . . .. . .. . . . . . . . . . .. . . . . . . .. 41

Characterization of Representative Feedstocks 45

Representative Alternative Feedstocks 49

"'Waste" Materials. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 49

Materials from Food Processing - . . . . . . . . . . . . . . . . . . . . . . . . . . .. 49

Materials from Cellulosic Biomass . . . . . . . . . . . . . . . . . . . .. 51

Dedicated Crops 51

Conventional Food Crops 52

Advantages and Disadvantages of Selected Renewable Feedstocks 55

2.52.2

2.52.3

3.0

3.1

3.2

3.3

3.3.1

3.3.1.1

3.3.1.2

3.3.1.3

3.3.1.4

3.4

1.12.3

12

1.2.1

1.2.2

1.2.3

1.2.4

1.2.5

1.2.6

1.2.7

2.0

2.1

2.2

2.3

2.3.1

2.3.2

2.4 .

2.4.1

2.42

2.4.3

2.4.4

25

2.5.1

2.5.1.1

25.2

2.5.2.1

1.1.2.2

Acknowledgements •....................................................................... 1

TABl..E OF CON1'EN1'S 3

LIST OF FIGURES 7

LIST OF TABLES .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 8

11

11

11

1.0

1.1

1.1.1

1.1.2

1.1.2.1

3
5.1.9

5.1.10

5.1.11

5.1.12

5.1.13

5.1.14

5.1.15

5.2

5.2.1

5.2.1.1

3.4.1 Feedstocksfor Bioprocesses 55

3.4.2 Lignocellulosic Feedstocks 58

4.0 THERMAL/CHEMICAL ROUTES TO PRODUCTS 61

4.1 General 61

4.2 Description of Screening Methodology for Thermal and Chemical Processes 63

4.2.1 Screening Based on Comparative Raw Materials Cost Contribution 64

4.2.2 Preliminary Detailed Process Evaluation 66

4.3 Summary of Technoeconomic Evaluation 67

4.4 Current and Projected Markets for Selected Chemicals from Biomass 67

4.4.1 Butadiene 67

4.4.2 Pentanes, Pentenes 71

4.4.3 Benzene •••••.•••••••...•...••.......•........•.......•............. 71

4.4.4 Toluene '72

4.4.5 Xylenes , . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. i3

4.4.6 Acetic Acid i3

4.4.7 Formic Add 74

4.4.8 Propionic Acid 74

4.4.9 Phenol 74

4.4.10 Resorcinol 75

4.4.11 Furfural ................•........................................... 75

4.4.12 Glucose 76

4.4.13 Gluconic Acid 76

4.4.14 Sorbitol 77

4.4.15 Mannitol 77

4.4.16 Xylitol . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78

4.4.17 Acrylic Acid 78

4.4.18 Cellulose Derivatives 78

4.4.18.1 Rayon Fibers 78

4.4.18.2 Cellulose Acetate Fibers 19

4.4.18.3 Cellulose Acetate Flake and Related Cellulose Esters 19

4.4.18.4 Cellulosic Surface Coatings 80

4.4.18.5 Cellulose Ethers 81

4.4.18.6 Cellophane .... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 81

5.0 INDIVIDUAL RAW MATERIALS COST COMPARATIVE EVALUATIONS 83

5.1 Direct Substitution 83

5.1.1 Butadiene 83

5.1.2 Pentanes/Pentenes tr7

5.1.3 Benzene/Toluene/Xylene (B1'X) •••••••••.•..••••••••••••...•••••••••. 88

5.1.4 Acetic/Formic/Propionic Acids 89

5.1.5 Hydroxyacetaldehyde 90

5.1.6 Phenolics (by pyrolysis routes) 91

5.1.7 Resorcinol 92

5.1.8 Vinyl Phenol, an Example of a High Value Phenolic Produced by

BiomassPyrolysis . . . . . . . . . . .. 93

Phenolics from Wood Phenolation 94

Phenolics (by hydrotreating of lignin) 95

SynGas 96

Acetic Add from Syn Gas fJ7

Peracetic Acid 98

Anthraquinone 99

Acrylic Add/Esters 100

Improved Production .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . .. 102

The NREL Oean Fractionation Process 102

Glucose 104

4
5.2.1.2

5.2.2

5.2.3

5.2.4

5.2.5

5.2.6

5.2.7

5.2.8

5.29

5.2.10

5.2.11

5.2.12

5.3

5.3.1

5.3.2

5.3.3

5.3.4

5.3.5

5.4

5.4.1

5.4.2

5.4.2.1

5.4.2.2

5.4.23

5.4.2.4

5.4.3

5.4.4

5.4.5

5.4.6

6.0

6.1

6.2

6.2.1

6.2.2

6.3

6.3.1

6.3.1.1

6.3.2

6.4

6.4.1

6.4.1.1

6.4.1.2

6.4.1.3

6.4.1.4

6.4.15

6.4.1.6

6.4.1.7

6.4.2

6.4.3

6.4.3.1

6.4.3.2

6.4.3.3

Xylose 106

5-Hydroxymethylfurfural . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 107

Levulinic/Fonnic Acids 107

Succinic Acid 108

Gluconic Acid 109

Sorbitol 110

Mannitol ............ ............•.................................. 111

Xylitol " 111

Furfural 112

Furfuryl Alcohol 113

Furan/Tetrahydrofuran (THF) . . . . . . . . • . . . . . . . . . . . . . . . . . . . . . • . . . . . . •. 114

Polyhydroxybutyrate/Polyhydroxyvalerate (PHB/PHV) 115

New Building Blocks/Products 116

I..evoglucosan ....._. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 116

Cellulose (Kraft)/ Anthraquinone 117

Cellulose (Organosolv)/Anthraquinone 117

Starch Plastics .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 118

Acetylated Wood 118

Selected Detailed Production Cost Estimates 119

General Information . . . . . ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 119

Detailed Process Analysis - Anthraquinone (AQ) from Low Molecular

Weight Lignin 121

Definition of Process Chemistry 121

lJefinition of Base Cases 122

Results of Evaluation 122

Evaluation of Competing Routes to AQ 122

Detailed Process Analysis - Phenolics from Biomass by PYrolysis and

Wood. Phenolation 126

Detailed Process Analysis - Clean Fractionation of LignoceUulosics 126

Detailed Process Analysis - Acetylated Wood. . . . . . . . . . . . . . . . . . . . . . . . .. 128

Detailed Process Analysis - Starch Plastics ". . . . . . . . . . . 129

BIOPROCESSING ROlITES TO GlEMICALS AND MATERIALS 131

Introd.uction and Rationale ..............•............... ..... ............... 131

Target Products and Markets for Chemicals . . . . . . . . . .. 132

Direct Substitution for Existing Chemicals .". . . . . . . . . . . . . . . . . . . . . .. 132

Development of New Chemicals, Materials, and Feedstocks 132

Opportunitiesfor Technology Improvement 133

New Technologies in Genetic and Metabolic Engineering ...•.......... ... 134

Future Technological Advances 135

Advanced Bioprocessing Concepts 136

Product/Process Selection ...............•.... ............................... 137

Initial Product Screening Methodology 138

Fraction of Revenue for Feedstock 140

Feedstocks Evaluated 140

Byproducts 141

Experimental Yields 142

Theoretical Yields 142

Product Values 144

SUIIlIIlaty" ••.•.•••.......•.•. .........••.••.....•..........•. 144

Comparative Evaluations 144

Integrated Product/Process Screening Methodology 147

Process Design 147

Profitability Analysis 148

EoononUc~ptions 149

5
Sensitivity Analyses 149

Sununary 149

RESULTS OF INITIAL ANALYSIS 153

Initial Targets : . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . 153

Applying Prioritization Methodology .................. ..•.................. . 153

Comparative Evaluations 158

Acetic Acid 159

Acetone 161

2,3-Butanediol .... ... ....... ...... ...•.......... ..... .... ........... 163

Butanol ........ ... • . ..•..... ..•..... ..... . ... .... ............ ...... 165

Butyric Add 167

Glycerol . •• . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 169

Isopropanol .............•.......................................... 171

Malic Acid 173

Polyhydroxybutyric Acid ...•...•.................................... 175

Propionic Acid ....•................................................. 177

Propylene Glycol ......•.......•..................................... 179

Succinic Acid •............................. ..... .................... 181

Qualitative Influences 183

Initial Candidates for Process Evaluation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 186

Organic Acids (Succinic/Malic/FumariC> . . . . . . . . . . 186

Market Definition 186

Process Evaluation 188

Process Concept ...• ••.......... ......... .......... .... 188

Profitability Analysis 190

Application of New Technologies in Genetic and Metabolic

Engineering to Succinic Acid 196

Advanced Bioprocessing Concepts 196

Neutral Solvents (Butanol) 201

Market Definition 201

Process Evaluation 200

Application of Genetic and Metabolic Engineering to Butanol

Production 207

Advanced Bioprocessing Concepts '11J7

RECOMMENDATIONS ..............•..................... .... .................. . 211

Criteria for RecOIllIIlelldations 211

Crosscutting Technical Barriers .........•.................................... 215

Near Term Opportunities 216

Mid Term Opportunities •....•.......... . . . . . . . . . . . . •. . . . . . . . . . . . . . . . . . . . . .. 219

Long Term Opportunities 220

Recommendations in Other OOE Program Areas and in Other Federal Agencies 221

Timefrarne for Completion ' 225

REFERENCES AND SELECTED BIBUOGRAPHY 227

7.5.2.4

8.0

8.1

8.2

8.3

8.4

8.5

8.6

8.7

9.0

7.5.1.4

7.5.2

7.5.2.1

7.5.2.2

7.5.2.3

6.4.3.4

6.4.3.5

7.0

7.1

7.2

7.3

7.3.1

7.3.2

7.3.3

7.3.4

7.3.5

7.3.6

7.3.7

7.3.8

7.3.9

7.3.10

7.3.11

7.3.12

7.4

7.5

7.5.1

7.5.1.1

7.5.1.2

7.5.1.2.1

7.5.1.2.2

7.5.1.3

6
UST OF FIGURES

- ' .

Figure 2.1

Figure 2.2

Figure 2.3

Figure 2.4

Figure 2.5

Figure 3.1

Figure 3.2 .

Figure 3.3

Figure 4.1

FigureS.l

Figure 5.2

Figure 5.3

Figure 5.4

Figure 6.1

Figure 6.2

Figure 6.3

Figure 6.4

Figure 6.5

Figure 7.1

Figure 7.2

Figure 7.3

Figure 7.4

Figure 7.5

Figure 7.6

Figure 7.7

Figure 7.8

Figure 7.9

Figure 7.10

Figure 7.11

Figure 7.12

Figure 7.13

Figure 7.14

Figure 7.15

Figure 7.16

Figure 8.1

Figure 8.2

Figure 8.3

Figure 8.4

Different Ways of Measuring Energy Consumed in Manufacturing 23

Scheme of the Chemical and Allied Products and Petroleum Refining Industries .' .. - 34

Interrelationships and Materials Flow for the Pulp and Paper Industry, 1986 38

Com PrOOuctsIndustry 39

CottonProductsIndustry 40

Production of a Generic Feedstock Intermediate from Representative BiomassBasedRaw Materials 43

Comparison of Selling Prices of Chemical Products with Representative Raw

Feedstock Materials 48

Projected and Current Domestic Production of Organic Acids and Neutral

Solvents 50

Schematic Outline of Technoeconomic Analysis 63

flowchart for Production of Product Families from Clean Fractionation 103

Comparison of Costs; BaseCasesfor Anthraquinone Production 124

Amortized Production Costs of AQ from Different Starting Materials. 125

Alternative Routes to Anthraquinone 125

.Metabolic Engineering . . . . . . . . . . . . . .. 134

Screening and Ranking Methodology . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 139

Initial Product Screening Methodology 145

Generic Example of Sensitivity Analysis ...••..•. ....•... . • . . . . . . . . . . . . . . . . . .. 150

Integrated. Product/Process Screening Methodology . . . . . . . . . . . . . . . . . . .. 151

Estimated Raw Material Cost Ratio versus Glucose Cost, Acetic Acid

Production 160

Estimated Raw Material Cost Ratio versus Glucose Cost, Acetone Production . . . .. 162

Estimated Raw Material Cost Ratio versus Glucose Cost, 2,3-Butanediol

Production 164

Estimated Raw Material Cost Ratio versus Glucose Cost, Butanol Production 166

Estimated Raw Material Cost Ratio versus Glucose Cost, Butyric Acid

Prociuction 168

Estimated Raw Material Cost Ratio versus Glucose Cost, Glycerol Production 170

Estimated Raw Material Cost Ratio versus Glucose Cost, Isopropanol

Production ........•...•.................................................... 172

Estimated. Raw Material Cost Ratio versus Glucose Cost, Malic Acid Production ... 174

Estimated Raw Material Cost Ratio versus Glucose Cost, Polyhydroxybutyric

Acid Production 176

Estimated Raw Material Cost Ratio versus Glucose Cost, Propionic Acid

Production •.............•........................................•......... 178

Estimated Raw Material Cost Ratio versus Glucose Cost, Propylene Glycol

Production ...................... ....................•...................... 180

Estimated Raw Material Cost Ratio versus Glucose Cost, Succinic Acid

Prociuction 182

Process Concept for Bioproduction of Succinic Acid 189

Metabolic Pathway for Production of Succinic Acid 197

Process Concept for Bioproduction of Butanol 204

Metabolic Pathway for Butanol Production . . . . . . . . . . . . . . . . 208

flowchart for Production of Chemicals Available from Renewable Materials 212

Production of Consumer Products from Renewable Feedstocks 214

Coordination of Research and Development Opportunities Across Federal

Agencies 222

Typical Demonstration and Commercialization Time Frame 225

7
UST OF TABLES

Table 2.1

Table 2.2

Table 23

Table 2.4

Table 25

Table 2.6

Table 2.7

Table 3.1

Table 3.2

Table 3.3

Table 3.4

Table 3.5

Table 3.6

Table 3.7

Table 3.8

Table 3.9

Table 3.10

Table 3.11

Table 3.12

Table 3.13

Table 3.14

Table 4.1

Table 4.2

Table 4.3

Table 5.1

Table 5.2

Table 5.3

Table 5.4

Table 55

Table 5.6

Table 5.7

Table 5.8

Table 5.9

Table 5.10

Table 5.11

Table 5.12

Table 5.13

Table 6.1

Table 6.2

Table 6.3

Table 6.4

Table 7.1

Table 7.2

Table 7.3

Table 7.4

Table 7.5

Table 7.6

Energy Intensity in Manufacturing Industry Groups: 1980,1985,and 1988 . . . . . . . . . .. 22

Environmental Legislation Affecting the Pulp and Paper Industry Since 1970 'Z7

Shipments from the United States Chemical Industry by Relevant Sectors 32

Selected Prices in Constant 1990 Dollars for Primary Petrochemicals 32

Source of Primary Petrochemicals in the United States (1990) 35

Selected End Uses of Plastic Products ..................•...................... 35

Plant Matter Derived Industrial Materials and Important Intermediate

Chemicals in the United States .......................•...................... 38

Representative Alternative Feedstocks: Primary Feedstock Constituents and

Current Uses 46

Recoverable Biomass Wastes 46

Prices, Production, Potential Fermentable Sugar Yields, and Productivities of

Representative Feedstocks(United States) 47

Com Kernel: Composition of Parts (% Dry Basis) .......•...................... 52

Protein in Com Grain Fractions (% of Total Nitrogen) ...•....................... 52

Com Genn Meal Composition (Solvent Extracted) 53

Com C>il CoIIlpOnents ....... ..............................•................. 53

Refined Com Oil; Average Fatty Acid Composition 53

Com Bran (Hull) Composition .......... ..............•...................... 53

Major Components of Com Wet Milling Steepwater 55

Com Cobs: Proximate Composition (% AsIs) ...••.•.•.•..•..•..••.••..•••..... 55

Positive and Negative Characteristics of Representative Feedstocks S7

Cell Wall Constituents of Biomass (%) •...•........•••....••.•.....••.•...... 59

Chemical Composition of Some Common Fibers 59

Summary of Compounds Selectedfor Screening 65

Detailed Process Evaluations Performed 66

Market Information for Selected Chemicals 68

Summary of Phase I Screening Results (Raw Materials Cost Contribution) 84

Summary of Key Economic Contributors to Amortized Production Costs from

More Detailed Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 120

Additional Assumptions for Process and Capital Cost Evaluations 123

Comparative Summary of Base Case Capital Investments (Millions of $) •..••.•.. 124

Comparative Summary of BaseCase Costs of Production ($lIb of Product) 124

Summary of Base Case Capital Investments (Millions of $) 127

Summary of Base Case Costs of Production ($/lb of Product) 127

Summary of Base Case Capital Investments(Millions of $) 127

Summary of BaseCase Costs of Production ($/lb of Product) 127

Comparative Summary of Base Case Capital Investments (Millions of $) •........ 128

Comparative Summary of BaseCase Costs of Production ($lIb of Product) 129

Comparative Summary of Base Case Capital Investments (Millions of $) •.•••.•.• 129

Comparative Summary of BaseCase Costs of Production ($lib of Product) 129

Feedstocks Evaluated and Current Prices 140

Feedstock Compositions 141

Feedstock Coproduct Values 142

Technical and EconomicAsswnptions 149

Bioprocessing Element Product Portfolio Candidates and Market Values 154

Portfolio Candidate Yields: Demonstrated and Theoretical . . . . . . . . . . . . . . .. 154

FRFResults using Wet-Milled Com as the Feedstock 156

FRF Results using Hybrid Poplar as the Feedstock . . . . . . . . . . . . .. 156

Initial Candidate Oassification 157

Qualitative Influences on Selection Process 184

8
'.1

Table 7.7

Table 7.8

Table 7.9

Table 7.10

Table 7.11

Table 7.12

Table 7.13

Table 7.14

Market Information for Succinic Acid/Succinic Anhydride and Potential

Derivatives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 187

Unit Raw Material.Costs 190

Unit Utility Costs 190

Manufacturing Cost Summary, SuccinicAcid from GlucoseSyrup 192

Performance Criteria Comparisons for Advanced Technologies, Succinic Acid

Production 200

Market Infonnation for Butanol and Potential Derivatives 202

ManufacturingCost Summary for ButanolProduction from Glucose Syrup . . . .. 205

Performance Criteria Comparisons for Advanced Technologies Butanol

Production 210

9
1.0 EXECUIlVE SUMMARY

1.1 Report Overview

1.1.1Introduction

Chemicals from renewable resources!

Since the oil crises of the mid 19705, the idea of deriving our vital chemical feedstocks from renewable

resources in a sustainable manner has been frequently suggested asan alternative to producing chemicals

from petroleum-based feedstocks imported from unstable political regions. This resource document on

biomass to chemicals opportunities is a joint effort between industry and a national laboratory team

consisting of the National Renewable Energy Laboratory (NREL), Argonne National Laboratory

(ANL), Idaho National Engineering Laboratory (INEL), Oak Ridge National Laboratory (ORNL), the

Pacific Northwest Laboratory (PNL), and funded by the Office of Industrial Technologies of the U. S.

Department of Energy (DOE). The report describes the development of a technical and market

rationale for the incorporating renewable feedstocks into the chemical industry in both a qualitative

and quantitative sense. The term "renewable feedstocks" can be defined to include a huge number of

materials (as this report will reveal) such as agricultural crops rich in starch, lignocellulosic materials

(biomass), or biomass material recovered from a variety of processing wastes. It is hoped that this

report can be used as a starting point for industry, academia, and government RO&D programs to further

develop strategies to match their core capability with opportunities in specific biomass to chemicals

product families.

The goal of the DOE Alternative Feedstocks Program is to develop cost-effective and environmentally

acceptable technologies for producing chemicals and materials from the large, underused renewable

feedstock capacity in the United States. An opportunity exists to displace an estimated 3 quads1 of the

energy consumed as raw materials by the chemical and petroleum refining industries if RD&D are

carried out with industry, and commercialization is successful (1988EIAlDOE MECS). The target for

the Alternative Feedstocks program is to displace 1 quad by 2030.

No less than a national team effort is needed to realize these goals. Although technologies exist to

significantly reduce energy consumption using renewables, converting these technologies into cost

effective applications is difficult. Through the Alternative Feedstocks Program, a team approach

involving government, national laboratories, universities, and industries will be pursued to meet this

challenge and sharpen America's economic growth and competitive edge in world markets. New

technologies being developed for this program include integrating advanced biological processes for

renewables into the mainstream of chemical processing; employing thermal and chemical processes for

rapidly and selectively converting renewable resources into new chemicals; developing renewablesbased processes that will reduce waste emissions and increase both energy and economic efficiencies;

and establishing the concept of biomass refineries and chemical coproduct opportunities for other

industries (agriprocessing, pulp and paper) that will provide domestic sources of chemical raw

materials and simultaneously create new American job opportunities.

Today, the civilian market is the driving force behind advanced technology, such as that described in

this report. The Alternative Feedstock Program will stimulate the manufacturing base in the United

States as well as expand existing and future efforts in the chemical, biotechnology, petrochemical, and

agriprocessing industries. The industries with the most to gain by this program have a great impact on

the domestic economy. In terms of employment, the renewables sector employs more than 3 million

people (agriculture/forestry, lumber/wood products, furniture, textile mill products, and paper/allied

products). The petroleum exploration and related chemical industries employ nearly 1.4 million people

lOne quad =1 quadrillion (1015) British thermal units (Btu) = 2.52 x 1014 kcal =1.0559 x 1018 J

11
(oil/gas extraction, chemicals and allied products, petroleum and coal products, and rubber and

miscellaneous plastic products). Adding new crops and products destined for chemical processing

facilities could stimulate regional economic development in currently depressed sectors and be an

integral part of a more secure job infrastructure for the 21st century.

This report will demonstrate the benefits of a wider incorporation of renewable alternative feedstocks

into the chemical industry as raw materials. The chemicals and allied products and petroleum and

refining industries used 11.7 quads of energy in 1988 (OOE/EIA~552, adjusted for electric power

generation efficiencies) giving them a Significant role in the nation's energy consumption. In addition,

the chemicals industry has the distinction of being one of the few industrial sectors in the United States

that has maintained a positive balance of trade in recent years. However, the continued growth of this

sector of the economy is at risk. Many of these raw materials used by this sector are now imported from

sources that are politically unstable and in the long term whose supply will continue to be depleted

until prices become prohibitive.

Several authors have correctly stated that petroleum is and will continue to be a major motivating force

of the industrial society (Yergin, 1991). Natural gas and its liquids are important and their role will

continue in the near future in the industrial economy. Some estimates suggest that relatively cheap

hydrocarbon-based feedstocks will be available well into the next century (Spitz 1988). Specifically,

as crude oil prices continue to increase, C-1 chemistry, based on coal gasification and converting coalderived synthesis gas to chemicals and other alternatives (such as natural gas) will become important.

However, other pressures are coming to bear on "business as usual." In spite of a seeming complacency

about oil and natural gas as primary resources for energy and chemicals, there is a climate change in

industry. One driver for the changes is growing public concern about the environment and the resulting

legislative response. Recognition that increased levels of atmospheric carbon dioxide produced in

burning organic materials (primarily fossil products) could result in global climate change has made

developing renewable sources of fuels and chemical feedstocks important to the nation's security. The

cost of compliance with environmental laws is increasing (for example, difficulties in obtaining drilling

rights on Alaska's North Slope, or in offshore areas). Other drivers include a simultaneous

globalization of the industry that allows other countries to offer lower cost feedstocks and a variety of

business and other incentives. To avoid such a shift and maintain jobs, it is essential to provide

domestic industrial sectors with opportunities to increase their profitability in the United States by

improving the efficiency of their processes and competitiveness of their products. Alternative

feedstocks strategies have the potential to be cost-effective because they expand value-added product

opportunities unique to renewables or advanced processing technologies that protect the environment, r=.'

and will allow the United States to avoid importing a substantial fraction of its refined petroleumbased chemical building blocks in the future.

Many different components impinge on the concept of integrating renewable feedstocks into the nation's

chemical production stream, and a single report can only offer a guide to many of the issues involved.

However, this report is intended to begin describing in a qualitative and quantitative manner the

advantages that would result from a large scale implementation of this program. For example:

• Substituting renewable feedstocks for petroleum-based chemical intermediates could

potentially lower crude oil demand, thus limiting economic downturns in the chemical industry

due to oil price volatility.

• Using biomass feedstocks can expand the options of the chemicals industry by increasing

feedstock flexibility and by broadening the spectrum of potential chemical products

(Biomarkets: 43 Market Forecasts for Key Product Areas 1991).

• Because imports are reduced as biomass is substituted for fossil resources, the balance of

payments deficit also decreases.

12
• Producing biobased chemicals may provide an acceptable answer to the current problems that

the petroleum-based chemicals industry faces in terms of generating hazardous waste and

responding to public and political pressure to protect the environment (Russell et al. 1992;

Stavins and Whitehead 1992).

• Carbon dioxide is recycled when new biomass is grown to replace that harvested for producing

chemicals, and there is not a significant contribution to carbon dioxide accumulation in the

atmosphere. In fact, if durable goods are made from biomass, carbon is sequestered for long

periods of time, actually countering a build up of carbon dioxide in the atmosphere from fossil

fuel use.

• Advances in metabolic engineering, bioprocessing, and separations technologies currently

provide an unprecedented opportunity to overcome the key technical and economic hurdles

limiting industrial applications.

• Environmentally sound biological processes for new productsfrom renewable resource feedstocks

could enhance industrial productivity. Indeed, it is estimated that the bioprocessing industry

could grow to become a $50 billion/yr industry by the year 2000 if sufficient investments are

made in research and education (National Academy of Sciences 1992). Producing chemicals

based on renewable resources represents an opportunity to realize this potential, and enable

U.S. industry to dominate in this area in the future with economically and environmentally

sound products and technologies.

• The window of opportunity for global conunercialization of several products and technologies is

in the near to mid-term timeframe (0-5 years, 5-10 years, respectively); however, they must be

developed and demonstrated at sufficient scale to lower the investment risk to United States

industry for commercialization.

What will the reader find in this report? First, for convenience, two broad areas of investigation are

covered throughout the report: converting renewable materials into useful feedstocks by thermal or

chemical means, and converting materials through bioprocessing. Although a number of the sections are

divided according to these disciplines, the reader must recognize that different approaches offer

different advantages. Some materials may be best prepared by thermal or chemical technology, and

others are most efficiently obtained through bioprocessing. In many cases, a hybrid

chemical/biological approach could offer the most cost-effective route to a product.

Section 2.0 attempts to review the many factors potentially influencing the feasibility of an

Alternative Feedstocks program. Summarizing this vast amount of information in a readable form is an

extremely difficult task, and a single report cannot give exhaustive coverage of all areas. Readers are

directed to consult the other references listed in section 9.0 for more detail.

Section 3.0 moves more deeply into a key issue confronting an alternative feedstocks program,

specifically, the availability of the renewable material necessary for producing chemicals. Questions

of feedstock quality, long-term availability, production infrastructure, and feedstock flexibility will

all impact the success of an industrial effort.

More importantly, sections 4.0 - 7.0 of the report describe a methodology developed to identify

different promising RD&D opportunities on a more quantitative basis, and categorize them as near (0-5

years), mid- (6-10 years), and long-term (greater than 10 years) possibilities. Since each reader will

bring his or her own perspective to this report, no attempt has been made to "sell" certain opportunities

at the expense of others. Rather, readers in government, industrial, and academic environments are

encouraged to use the results of this report within the unique context they can provide. As an example,

DOE has used the information provided. in this report to prepare a program document that provides a

13
general overview of the alternative feedstocks effort, a description of the specific RD&D areas

recommended for funding that fit current DOE goals.

L1.2 Overview ofthe Technoeconomic Evaluation of Proposed Process Routes from Renewables

A key component and the major portion of this report describes a quantitative, comparative

technoeconomic evaluation of the potential costs and benefits of incorporating renewables into the

nation's chemical feedstock stream. A screening methodology was needed so that technologies for

chemicals and materials from biomass could be organized for near-, mid-, and long-term development

objectives. The methodology needed to identify necessary RD&D that could be carried out with

industry to develop the most promising examples of these technologies to commercial success.

An evaluation was carried out on both the proposed thermal, chemical and biological processes, and

where possible, directly compared to existing hydrocarbon-based technologies. SOmedifferences exist

in the details of the evaluation methodology employed for the chemical and biological evaluations

(described in depth in sections 4.0 - 7.0 of the report), but both attempt to answer a central question:

Given a wide range of possibilities, how can an informed decision be made as to which materials to '

investigate more thoroughly?

Caution must be used when reading the results of these technoeconomic evaluations. They are

approximations, and intended to serve as "pointers" to those biomass-based processes that appear to

have a reasonable chance of competing with their hydrocarbon-based counterparts. However, a wide

range of subjective judgement is possible among many of the processes evaluated. The evaluations are

only as good as the process information currently available, and when exact information cannot be

obtained, then reasonable estimates must be made regarding potential process performance. As a result,

a process that shows high potential may not immediately be identified for further research because

the actual process needs more definition. Conversely, a process showing less favorable potential after

evaluation may be ideal for further study because a well defined process exists. Other criteria can also

be important, including energy impact, environmental quality, economic competitiveness, and

probability of success. It is expected that readers of this report will impose their own expertise and

additional judgement criteria on chemicals and processes of interest. Feedback from readers on how to

make the screening methodology more valuable will be greatly appreciated and encouraged by DOE.

Evaluating the processes and materials provided an additional benefit. This investigation helped

define related RD&D areas that, if pursued, would improve the outlook of certain processes, and of the

overall industrial concept. These related areas are also listed as part of the recommendations.

L1.2.1 Overview ofTechnoeconomic Evaluation of Thennal and Chemical Processes

The evaluation of thermal or chemical processes uses a simple but well established method: the raw

material cost contribution for producing a chemical from biomass is compared to that for producing the

same chemical from hydrocarbons. In those cases where a direct comparison was not possible (for

example, in situations where a petrochemical-based process is not known), a comparison was made

between the existing process and processes that could improve production of that material.

. Because new ventures always involve some uncertainty, the evaluation of the biomass-based process

was then adjusted upward by a risk factor of 30%,i. e., any new process should show a 30% improvement

over existing technology to justify investment (a well established rule of thumb in industry for a

pioneering new venture). These two simple steps provide a set of numbers for comparison as the ratio:

Raw Materials Cost Contribution for Petrochemical (or other) Process

Raw Materials Cost Contribution for Biomass Process x 1.3 (risk factor)

14
Those ratios significantly less than one indicate that the existing routes to a chemical have a

considerable advantage over a new biomass-based process, and ratios significantly greater than one

indicate that the biomass-based process could be an attractive candidate for further investigation.

However, these numbers are approximations and are intended to augment an informed judgement by the

reader. A ratio of 0.9 or even 0.8 is certainly not a reason for a uno go" decision; a ratio of 1.2 or 1.3 is not

a reason to devote all efforts to a single material.

Where existing research results and process information warrants, a more detailed analysis has been

made. These evaluations (detailed in section 5.0) include an analysis of expected capital and operating

costs of a large scale biomass-based facility for producing certain chemicals, and projects an amortized

production cost for the chemical.

1.1.2.2 Overview of Technoeconomic Evaluation ofBiological Processes

The screening methodology used to select and classify biological processes is similar to that used for the

thermal and chemical processes. The first step evaluates products using very approximate economic

analysis based only on the prices of the products and starting materials, and compares the cost of the

feedstock to the value of the material derived from that feedstock. Very simply, if the cost of the

feedstock is more than the value of the products, then the process will probably not be economically

viable.

The second step is a comparative analysis of the proposed bioprocessing route with the conventional

petrochemical processing route. These results are also approximate because the method considers only

the major raw material cost contribution of each route, similar to the method used in the evaluation of

the thennal and chemical routes. This step of the evaluation also includes the 30% adjustment to cover

uncertaintiesin projecting the costs associated with a new process.

The results of this analysis are used with various qualitative judgements to decide the order in which

products are evaluated under the final screening stage. This qualitative opinion falls under the four

broad categories of Energy Impacts, Environmental Quality, Economic Competitiveness, and Probability

of Success. The final screening is a preliminary grade estimate of the total capital investment for the

project, and using various economic assumptions, a prediction of a required product selling price. This

predicted selling price is compared to the current market value and the products are ranked according to

this difference.

1.L2.3 Improving the Evaluation Process

One of the significant products from this study has been the development of a methodology for assessing

and screening the economic potential of a variety of processes to produce biobased products. The

screening and analysis methodology provides a rational and systematic approach to discriminate

between potential processes. The methodology haslargely been market based, but environmental costs

are an important dimension that was not included in the initial analysis. It is the intention of the

Alternative Feedstocks program to investigate, evaluate, and quantify the environmental aspects of a

potential product or process for incorporation in the overall evaluation methodology. This will

provide another dimension to the screening and pennit an estimate of the environmental costs

associated with the use of any specific process.

1.2 Recommendation Overview

1.21 Thermal and Chemical Recommendations

As a result of the evaluation process, several processes or materials have emerged as potential RD&D

opportunities. A number of different criteria were used in assigning these areas, including current level

of knowledge, current scale of operation, estimated time required for potential commercialization, etc.

15
Some of these processes proceed well, but only on a laboratory scale. Others have been operating for

several years at multipound scales, or have been commercialized in the past. Details for each of these

processes are given in later sections of the report. However, they fall nicely into the near-, mid-, and

long-term scenarios. Of course, readers will bring their own criteria to this report and may find it more

logical to reclassify some of the processes and materials assessed.

It is important to note that placing a given chemical or process into one of these three categories does

not immediately mean that RD&:D will realize a result within the broad definitions of each of these

timeframes. Certain materials may better be classified as near-mid or mid-long. RD&:D could reveal

that an opportunity originally classified as near-term requires more investigation; conversely, an

originally long-term proposition may be brought to commercialization rapidly by unexpected

breakthroughs. However, for simplicity, subdividing the categories was not considered.

The analysis of potential products from thermal or chemical processes suggests that four products could

be suitable for further development within either near- or midterm timeframes: cellulose, lignin, and

hemicellulose from clean fractionation of lignocellulosics and the production of acrylic acid,

anthraquinone or peracetic acid. It should again be emphasized that this analysis and selection was

made from a limited range of options and hence is limited in scope. As a wider range of options is

analyzed, equivalent or even better choices may become obvious.

l.2.2 Bioprocessing Recommendations

Over the past decade a series of technological advances has occurred that promise, in concert, to

significantly improve the economic competitiveness of biobased processes. Evaluation of this window

of opportunity focuses on the inherent attributes of biological processes, application of new technology

to overcome past limitations, and integration with nonbiological process steps.

The bioprocessing element of the Alternative Feedstocks Program is attempting to define the most

economical chemical candidates that could be produced biologically from renewable resources to

provide feedstock flexibility to the chemical industry and accrue multiple benefits to the United States

economy in energy security, economic growth, and environmental stewardship.

The initial emphasis of the program has been on the evaluation of the potential and economic

opportunity of biobased products. The ongoing product/process screening analysis is supplemented by

surveys on feedstock availability, market potential, improved biochemical pathways, and advanced

bioprocessing concepts. literature surveys and evaluations have been done in consultation with an

industrial panel. The results of the initial product screening analysis and industrial participation gave

two classes of potentially important bioproducts: organic acids and neutral solvents. Specific

representative targets, succinic acid and butanol, respectively, were selected for further evaluation.

Additional product classes are being examined.

A focused research and development effort is needed for portfolio candidates classified as near-term

opportunities to improve both the process and the microbial metabolism. Six primary criteria will be

used to evaluate possible advanced bioprocessing concepts and the potential of metabolic pathways

modifications. Each of the possible innovations will be considered on the basis of (l) volumetric

productivity (2) yield as a fraction of theoretical (3) the product quality in purity and concentration (4)

the energy use inherent in the process (5) the potential environmental impact and (6) the operability.

1.2.3Developmental Process for Recommended Products and Processes

The program will take advantage of basic concepts, initiated under other programs, which show

potential of marketability for biobased products. These concepts will be economically evaluated to

estimate the impact. The best concepts for the target compounds will generally be taken directly to the

developmental stages. Industrial involvement is considered critical and will be actively pursued

16
throughout all phases of the development efforts. Often, it will be apparent that additional research

is necessary to utilize the process. Research support will be sought from other DOE offices or other

federal agencies to address these research issues.

A laboratory demonstration of the process components will be perfonned for the target compound. This

work may be carried out at various sites. Results from this demonstration will be used to design a

complete field pilot unit for testing at an industrial site. The results will also be used to refine the

economic model. It is expected that industrial participantts) will have an increased role at each stage

of development. The final stage will be a pilot plant constructed through cost sharing with the

industrial participant.

Projects in the program will be market driven. However much of the RD&D may have generic

applicability to an entire class of materials, such as improved separation for organic acids or improved

pretreatment of lignocellulosics, The projects will tend to focus on the actual developmental

demonstration and economic evaluation of real products and processes. Near-term projects (1 to 5 years)

were preferred for this first screening, but mid-term (5 to 10 years) projects were also considered.

Advanced techniques will be employed when theenhance process economics.

Many technical issues exist, both generically and specifically for certain target products. Although

this program will focus on commercialization of specific representatives of chemical product families,

there are barriers that are common to many potential products from renewables. Broader infrastructure

barriers that must be examined for the larger industry include: the interface between the agribusiness

and the chemical processing industry, the presence of a qualified pool of trained personnel for this new

industry (National Academy of Sciences 1992), and the consumer acceptance or awareness of "green"

products from renewables.

1.2.4 Near Term RD&D Opportunities

The evaluation process identified several possible RD&D opportunities that fall roughly into the

near- term timeframe. For bioprocesses, succinic acid was identified as one opportunity. For thermal

chemical processes, two potential opportunities were identified which will need further evaluation

prior to actual development: producing cellulose, lignin, and hemicellulose by dean fractionation and

producing acrylic acid. Additional thermal and' chemical opportunities are identified here and

additional bioprocessing options are described in sections 6.0 and 7.0, and specifically in Table 75.

1. Succinic acid produced from corn syrups provides an opportunity that has significant potential

to demonstrate the feasibility of producing a commodity type chemical from renewable

resources.

2. Clean fractionation of biomass is a process being developed at NREL that allows separating

lignocellulosic material into its three primary components (cellulose, hemicelluloses, and

lignin), more cleanly than current technologies.

3. Acetylated wood, a material that can be made from wood and waste fibers that shows

significant improvements in dimensional stability and resistance to biological degradation in

comparison to other materials, appears to be ready for process development and pilot

demonstration if industrial interest and markets can be developed.

4. Starch plastics are materials that find uses in producing biodegradable plastic packaging or

other applications. Further evaluation of their production will be important, especially where

chemical modification is used to impart specific properties.

5. Fast pyrolysis of wood offers phenolics to be used in molding compounds and adhesives

manufacture and other promising chemicals. A related process, lignin hydrotreatment, also

17
offers a route to these materials. Another related process, wood phenolation, involving the

catalyzed reaction of phenol and wood gives a liquid product used in producing phenolformaldehyde thermosetting resins.

6. Benzene, toluene, and xylene can be made from wood, but are currently experiencing a static

market in the United States. These materials could be developed on a small scale in countries

that need these chemicals and cannot import or produce them, but have a renewable feedstock

base available.

7. Acrylic acid can be prepared using a process being developed at PNL. The process uses

bioprocessing and chemical processing for converting waste starch products. Engineering

development of the process will help to validate initial teehnoeconomic assessments.

1.2.S Mid Term RD&D Opportunities

The evaluation process identified several possible RD&D opportunities that fall roughly into the midterm time frame for development. These are generally processes or products that require some

additional research and development to improve market acceptability or process economics. They are

likely candidates for the next generation of product candidates for the program. For bioprocesses, one

opportunity was identified among the neutral solvents, butanol production. For thermal and chemical

processes, two potential candidates were identified, anthraquinone and peracetic acid. Additional

thermal and chemical examples are identified here and the additional bioprocessing opportunities are

discussed in sections 6.0 and 7.0, and specifically in Table 7.5.

1. Butanol from bioprocessing could be a major commodity chemical that has application as a

feedstock for such products as butyl butyrate, which is being considered as a "green" solvent.

2. Xylose, xylitol, furfural, £Uran resins, tetrahydrofuran, glucose, gluconic acid, sorbitol,

mannitol, levulinic acid, and succinic acid are materials that could be prepared from

inexpensive cellulose and hemicellulose derived sugars, available from clean biomass

fractionation.

3.

4.

Anthraquinone, a well known pulping catalyst and chemical intermediate, can be prepared

from lignin using a process being developed at NREL and the Institute of Paper Science and

Technology. Engineering and parallel process development should be pursued to validate

initial laboratory test results.

Butadiene and pentanelpentenes can be prepared using fast pyrolysis followed by catalytic

upgrading on zeolite-type catalysts. The process could become important if feedstocks such as

refuse-derived fuel from municipal solid waste can be shown to perform adequately.

5. Acetic acid can be produced. from syn gas, a route that appears to be an interesting match given

the unique composition of synthesis gas available from biomass, and makes possible a balanced

process (through intermediate methanol) without the costs of syn gas reforming.

6. Peracetic acid is an oxidant that is a good non-ehlorine containing pulp bleaching agent, but its

high cost is the key impediment to a more widespread use. A more detailed analysis of the

means of reducing the costs of peracetic acid would guide proposed research and permit market

penetration of this chemical into the pulp and paper industry.

1~6 Long Term RD&D Opportunities

Several interesting opportunities were noted during the analysis process as long-term opportunities.

They are characterized as needing significant RD&D prior to consideration as a potential product line.

18
Some examples of the thennal or chemical and bioprocessing options are listed here. More complete

analysis results are found in sections 4.0-7.0.

1. Levoglucosan can be prepared from fast pyrolysis of biomass and is a starting material for the

producing high value materials and specialty polymers. A specific levoglucosan derivative is

resorcinol, a cold setting adhesive that would have additional markets at lower cost. Markets

for these products will develop as research in Japan, Canada, and the United States increases.

2. Vinylphenol, a high-value specialty monomer used in coatings and microlithography, can be

made from biomass pyrolysis. With suitable biomass feedstocks, NREL research has shown

that significant Yields of this monomer can be produced.

3. Hydroxyacetaldehyde is a byproduct of the fast pyrolysis of wood. Methods to separate the

product need to be developed so it is valuable to the biomass pyrolysis refinery.

4. Polyhydroxybutyrate/valerate can be prepared from biomass derived syngas and could be a

cheaper precursor than glucose for these useful and biodegradable biopolymers. Verification of

the preliminary technoeconomic assessment would enhance the outlook of this process.

1.2.7Related RD8tD Opportunities

1. A basic understanding of reactions for selectively converting biomass and biomass derived

materials into chemicals is needed. A fundamental understanding of new catalytic processes for

selectively manipulating and modifying carbohydrates, lignins, and other biomass fractions

will greatly improve the ability to bring biomass derived products to market. The behavior of

oxygenated molecules on zeolite and other shape selective catalysts could lead to a better

design of processes for chemicals from biomass. Developing special catalysts for biomass

processing is not a high priority for the chemicals industry, but is essential for this new field if

it is to compete with petroleum resources and cost-effectively produce fuels and chemicals.

2. Databases that compile the details of producing candidate chemicals from renewables relative

to production from conventional processes would be useful for performing sensitivity analyses.

Including environmental databases would allow these analyses to address environmental costs.

3. The number of candidate chemicals and materials undergoing evaluation should be increased

using input from industry and the national laboratory team.

4. Several bioprocessing issues need to be addressed by basic and applied research. These include

processing dilute product streams, improving bioprocessing catalysts <usually microorganisms),

improving and adapting reactor designs, integrating feedstock preparation with bioprocess

operations, and developing process controls specifically applicable to renewables processing.

5. A fundamental understanding of clean biomass fractionation into its three subcomponents is

needed. The method being developed at NREL can carry this out relatively cleanly, but the

process is not yet well enough understood to permit widespread use among all biomass options.

6. Investigating the possible monomers that can be derived from pyrolytic processes would expand

the possibilities of using biomass as sources for chemical feedstocks.

7. Developing fast analytical methodologies for analyzing biomass is an enabling area for the

production of chemicals from renewables. These methodologies, that include new analytical

techniques and sensors, provide the basis for automated process control necessary for operations

with complex feedstocks and product mixtures, an important component of optimized industrial

production of chemicals and materials.

19
2.0 OVERVIEW OF FACTORS CONTRIBUTING TO ANALYSIS

Integrating renewables into the feedstock supply of the chemical industry is a complicated matter, and

requires consideration and knowledge of many different but interrelated factors. This section offers an

overview of several of these key factors that impinge on the potential benefits of the program (section

1.1.1).

2..1 Energy Considerations

A huge amount of energy equivalent is available in the fonn of renewable biomass. "Renewables" in

the context of this report refers to biomass derived from photosynthesis driven by solar energy and

residues from processing biomassresources into conventional products such as food, feed, and fiber. The

availability (in energy equivalent) of renewable resources is estimated (Szmant 1986) to be:

Worldwide biomass production:

Worldwide biomass utilization:

6.9xl017 kcal/yr (2740quads)

4.7xl016 kcal/yr (190 quads)

i, e., humankind uses only 7% of the worldwide biomass production for food, feed and fiber.

Using renewables in the United States reflects the low worldwide trend. Current levels of using

renewable resources for all uses (converted into energy equivalent) are:

ForestryIPulp and Paper (without fuel use) 4.6 quads (energy equivalent)

Agriculture grains only . 5.3 quads (energy equivalent>

Biomass industrial/residential 2.7 quads (energy)

Biomass to electric power generation 0.8 quads (energy)

Biomass transportation fuels (corn-to-ethanol) 0.1 quads (energy)

This breakdown gives a total of 13.5 quads currently used for conventional food, feed, and fiber and

emerging energy technology applications (Overend and Glum 1991).

Contrast the numbers for renewables with those for energy production and use from conventional sources.

In 1990, the United States produced 67.5 quads of energy (32% from coal, 27% from natural gas, 26.5%

from erode oil, 9% from nuclear and 4% from hydroelectric), but consumed 81.5 quads, that required

importing 14 quads. The major consumers of energy were the industrial sector (30 quads), buildings (29.3

quads), and transportation (22.2 quads). .

The activity of the industrial sector is of primary interest to the Alternative Feedstocks program and a

.deeper investigation of its energy needs is illustrative. The energy intensity of the industrial sector

alone, shown in Table 2.1, gives a different way of understanding its energy consumption (the Standard

Industrial Classifications are shown for convenience), and is a useful starting point for considering

energy used by the various manufacturing sectors. It is clear from Table 2.1 that chemicals and allied

products is especially energy intensive, ranking fourth only to the paper and allied products, and the

key inorganic and metals industries. Importantly, note that the petroleum refining industry is one of

the few examples of industrial sectors in which the energy usage is increasing with time. More energy

is required because the quality of starting crude oils is decreasing with time. This trend is expected to

continue as easily available and higher quality crude oil sources are depleted.

An interesting shift in the order of energy consumption presented in Table 2.1 results when other sources

of energy consumption are included (Figure 2.1; EIA Annual Energy Outlook 1992). For example, the

pulp and paper industry consumes large amounts of wood bark and associated processing wastes from its

chemical recovery processes to supply a little more than half the energy it requires (base plus

renewables). Other sectors shown on the graph do not have access to this energy source. Therefore, the

chemicals industry consumes large amounts of its petroleum and natural gas as feedstocks for

21
manufacturing products, but also must use large amounts of conventional fuels for process heat and

power, both of which can be viewed as an energy equivalent (Base, Renewable, Feedstocks). In

addition, inefficiencies in generating electricity have to be considered. With these additions, the

chemicals industry clearly becomes the largest energy consumer of the industrial manufacturing sectors,

and an appropriate candidate for RD&D to reduce this consumption.

Table 2.1 - Energy Intensity in Manufacturing Industry Groups: 1980,1985, and 1988 fIbousands

BTU/constant 1982 Dollars)

SIC 1972 Standard Industrial Oassification 1985 1988

32 Stone, Clay & Glass Products 21.5 16.7 16.7

33 Primary Metals Industry 16.3 14.6 14.4

26 Paper & Allied Industries 15.9 14.0 12.9

28 Chemicals & Allied Products 14.9 12.4 11.3

22 Textile Mill Products Industry 5.7 4.8 4.8

29 Petroleum & Coal Products 5.3 4.9 5.7

30 Rubber & Mise. Plastic Products 4.3 3.1 3.2

20 Food & Kindred Products 3.5 2.7 3.0

34 Fabricated Metal Products 2.7 2.3 2.4

25 Furniture & FIXturesIndustry 1.9 1.6 1.7

35 Fabricated Machinery & Equipment 1.7 0.9 0.8

36 Electronic & Other Electric

Equipment Industry 1.7 1.25 1.2

39 Miscellaneous Manufacturing Ind. 1.7 1.4 1.4

37 Transportation Equipment Industry 1.5 1.2 1.1

38 Instruments & Related Products 1.6 1.2 1.2

All Manufacturing 5.8 4.4 4.2

Source: Changes in Energy Intensity in the Manufacturing Sector 1980-1988. Manufacturing Energy

Consumption Survey. DOE/EIA-0552 (80-88), December 1991; for comparability, the data are

calculated based on the 1972 Standard Industrial Oassification System

Chemical production is also heavily dependent on fossil-based feedstocks. The chemical and allied

products and the petroleum refining sectors derive more than 98% of their primary organic

petrochemicals (methane, ethylene, mixed aromatics, etc.) from two feedstocks, crude oil and natural

gas (including two- to four-earbon natural gas liquids). Roughly 11.7 quads (5.0 in producing nonenergy

materials and 6.7 in process energy) are associated with using crude oil for producing chemicals. Over

the last 25 years, the nation's supply of crude oil has been increasingly derived from foreign imports,

making our supply of vital feedstocks vulnerable to politically unstable governments and the natural

volatility of crude oil prices. As supplies from these sources continue to be depleted, their price will

rise (and so will most prices of products that rely on oil derived sources for energy), as will the

manufacturing cost of refining crude oil or natural gas, again because of the decreasing quality of

available feedstocks. Considerable RD&D has focused on developing alternative fossil-based starting

materials for chemicals, including coal, oil shale, and tar sands. RD&D of conversion technologies using

these alternatives continues worldwide; fossil-based feedstocks, primarily coal and oil shale, are the

subject of extensive RD&D in the United States and other countries. Some of these resources, such as

electric energy production from coal, are already major players in the energy field in the United States

and other countries.

22
'.. -. -. ',

Energy Consumed in Manufacturing

Four Ways of Measuring It

.Refining Primary metals

Quadrillion

BTU

8

7

6

5

4

3

2

1

o

Chemicals All other

II Base Consumption '

II Base and Renewable

III Base, Renewable, Feedstocks

Including Inputs to Electricity

Pulp/paper

Sector P87·G0948903

Figure 2.1 - Different Ways of Measuring Energy Consumed in Manufacturing
2.2 Environmental Considerations

Today, industrial criteria for developing new processes and products continue to involve the traditional

parameters:

•

•

•

Economics

Productivity

Efficiency and functionality

Industry's view includes globalized market economies, that decrease constraints of operating within

the boundaries of One nation. Government tends to impose additional criteria:

•

•

•

Sustainability, stewardship, and managing national resources

Economic growth

Maintaining and improving living standards

•

However, a newer parameter is rapidly growing in importance as industry considers new processes:

Enoironmental impact both before and after using a product (waste management> and

maintaining, preserving, and improving the environment for future generations.

Selecting appropriate feedstocks for the future will ultimately be based on a balance between several

criteria, that include the cost of production and a global assessment of the cost to the environment,

however, industry is being asked to reevaluate its priorities and consider additional factors as they

assess their operations. These include:

•

•

•

•

•

•

Minimizing emissions to air, land, and waters in manufacturing products.

Assessing the toxicity and hazards of final or intermediate products to decrease the risk of the

operations on workers and neighborhoods.

The effect of processes and products on the global environment - the compatibility of products

and processes with the environment.

Waste management and disposal of waste (industrial/post-consumer) in an environmentally

and ecologically sound and cost effective manner. Product recycling and biodegradation

strategies are needed by industry as they are required by consumers and municipalities.

Resource conservation - efficient use of resources and minimizing effects of extracting resources

from the earth.

Alternative resource development - are there resources that could lead to better products with

less environmental impact with sufficient RD&D and commercialization?

Renewables can potentially address the energy and feedstock needs of industry without many of the

environmental costs incurred by continued use of fossil-based materials. The key word is

"environmentalism", that will become a major business in the '90s and beyond (Narayan, in Rowell

1992).

The idea that a "greening" of industry is needed resulted in key international companies and industrial

organizations meeting in Rotterdam to endorse a set of principles and a charter that will commit them

to environmental protection into the 21st century. A business charter for sustainable development was

adopted by more than 150 companies and 35 organizations. In support of this document, 16 principles

developed by the Paris-based International Chamber of Commerce (lCC) were adopted. These

principles are designed to place environmental management high on corporate agendas and to encourage

policies and practices for carrying out operations in environmentally sound ways. ICC's U.S. affiliate is

the U.S. Council for International Business, that expects that American corporate awareness of

sustainable development will emerge. Examples of principles in the ICC charter are:

24
• Developing and operating facilities that undertake activities with energy efficiency,

sustainable use of renewable resources, and waste generation in mind.

• Supporting and perfonning research on the impact .of raw materials, products and processes,

emissions and wastes, and ways to minimize this impact.

• Modifying manufacturing, marketing, or using products and services to prevent serious or

irreversible environmental damage; developing products and services that do not harm the

environment

• Contributing to the transfer of environmentally sound technologies and management methods.

The Earth Summit in 1992 also emphasized the need for developing partnerships that include many

countries, industries, and governments for establishing stewardship over the planet's resources and

environment. The Agenda 21 established 150 recommendations and a blueprint for the future, that 114

heads of state signed. Paramount was the concept of global partnership leading to the sustainable

development of the world. Recent United States signing of the carbon dioxide Rio accord that limits

greenhouse gas emissions in the year 2000 to 1990 levels suggests that alternative feedstocks could play

an important role in decreasing emissions. A national team approach of the Alternative Feedstocks

Program between laboratories, industries, and agriculture could provide a role model for this global

partnership for renewable-based economic sectors.

2.3 Legislative Considerations

Closely related to the growing public concern over the environment is the legislative response to this

concern. Industry is facing increasingly more stringent environmental regulations. The Chemical

Manufacturer's Association estimated. that in 1990, capital expenditures by the chemical industry for

pollution abatement amounted to $1.68 billion and annualized operating expenditures amounted to

about $3.83 billion. The figures for the pulp and paper industry are similar. In 1990, the National

Council of the Paper Industry for Air and Stream Improvement (NCASI) estimated that the necessary

capital expenditures for regulatory compliance were $1.27 billion, and consisted primarily of water

pollution abatement (50%), air pollution abatement (30%), and solid waste abatement (20%). These

capital investments, coupled with administrating applicable laws and regulations have increased the

product costs by $22/ton. Adding operating and maintenance costs results in an overall increase of

$35/ton of paper and paperboard produced, a total of $2.7 billion for the industry. These expenditures

represent a 20%increase in costs over 1989.

The chemical and pulp and paPer industries are subject to a number of common regulations, but the

impact of some is more important to one sector relative to the other. The following sections give details

about some of the key environmental legislation.

2.3.1 Chemical Industries (United States Department of Commerce, 1992)

Emergency Planning and Community Right-to-Know Act (3rd Title of the Superfund Amendments and

Reauthorization Act - 1986) - Title III

This act mandates emergency planning and gives communities the right to know about certain

hazardous materials used, produced, purchased, stored or shipped by industries. Title III sets specific

reporting requirements and deadlines. They include inventories of specific chemicals, material safety

data sheets, annual inventory of materials kept, and their releases into the environment. EPA has the

list of chemicals in a computerized data base, that the public has access to and the number of chemicals

covered is expanded periodically as is the level of the reporting required of the industry.

Clean Air Act (CAA)

This act prohibits hazardous pollutant discharges into the atmosphere in excess of emission standards.

The 1990 amendments impose new standards and regulate how many of these chemical pollutants will

25
._.. . '' .-:O J

: . " 0:

need controls in place by certain times. Thus, an added 41 compounds must be in place by 1995 and

another 148 by 2003.

Toxic Substances Control Act (TSCA)

This act regulates testing and manufacturing of chemical substances and mixtures. TSCA authorizes

Environmental Protection Agency <EPA) to require testing certain substances. The number of substancesis

being expanded and the specific testing requirements are being streamlined. The goal of the act is to

extend the number of chemicals tested through an international program with the Organization for

Economic Cooperation and Development. Each company is required to submit a premanufacture

notification (PMN) for each new chemical they wish to produce. This has a major impact on the

chemicals from biomass that are new or not identical to those produced through conventional methods.

The PMN is reviewed and additional testing may be required before production and commercialization.

The act can prohibit, limit, or ban the manufacturing, processing, and using chemicals. Substantial risk

information has to be reported under the act with substantial penalties for violations (e.g.,

$25,OOO/day in civil penalties).

Resource Conservation and Recovery Act (RCRA)

RCRA regulates managing hazardous waste from generation to disposal. Land disposal of hazardous

wastes has been banned unless no migration from the waste facility will occur as long as the waste

remains hazardous or the waste is treated to levels established by EPA. A number of regulations exist

that control handling and disposal, underground storage, and the number of chemicals that fall under

this category.

Implications of the act to the chemical industry according to the CMA is that $9-60 billion could be

required to clean up hazardous and non-hazardous sites during the next decade, depending on the rate of

program implementation and levels required.

Clean Water Act (CWA)

CWA guarantees continued progress in insuring high quality water. It prohibits discharges of

pollutants into navigable waters without a permit and increases the severity of civil and criminal

penalties for violations of the act.

Safe Drinking Water Act (SDWA)

National standards are set for contaminants to drinking waters. There are nine chemicals in the current

standard and an additional 62 are being added. Protecting groundwater quality and wellheads are part

of this act.

Chemical Diversion and Trafficking Act

The act addresses the problem of diverting chemicals to make illegal drugs. This act requires

controlling records of sales of chemicals, reporting suspicious transactions/unusual transactions, and

controlling export/import transactions.

Occupational Safety and Health

The Occupational Safety and Health Administration (OSHA) requires extensive documentation of

chemicals in trade, in the working place, and mandates warning labels on containers. Estimated annual

costs of compliance are about $400 million annually. OSHA also sets a hazard communications

standard, and state and local laws, that give workers the right to know about hazardous chemicals in

26
the workplace. The chemical industry currently complies with permissible exposure limits for about

600 hazardous substances.

2.3.2Pulp, Paper and Paperboard Industries

In addition to the above mentioned acts that also pertain to this sector, the Environmental Pesticide

Control Act applies to this industry. A summary of the legislation affecting the pulp and paper (much

of it in common with the chemicals industry) is shown in Table 2.2.

Particular problems of this industry pertain to the water pollutant discharges and control of dioxins.

These issues figure prominently as a major compliance requirement. Preventing dioxins and related

compounds from forming has had major impacts on the bleaching sector of the industry, both in the

technologies used (chlorine-free: oxygen, ozone, peradds, and other oxidizers) as well as developing

strategies to recycle the mill waters. EPA is developing a national industrial effluent limit guidelines

and standards based on the best-available, economically achievable technologies to reduce dioxin

contaminants and total chlorinated organics from manufacturing bleached paper products.

Table 2.2 - Environmental Legislation Affecting the Pulp and Paper Industry Since 1970

Year

1970

1972

1973

1974

1976

1977

1978

1980

1986

1987

1989-90

Legislation

Air Quality Standards Act (Clean Air Act; P. L. 91 - 604)

Water Quality Improvement Act (P. L. 91- 224)

Resource Recovery Act (P. 1. 91 - 512)

Occupational Safety and Health Act (P. L.91 - 596)

Water Pollution Control Act Amendments (p. L 92 - 5(0)

Environmental Pesticide Control Act (P. L. 92 - 516)

Oean Air Act Amendments (P. L. 93 - 15)

Safe Drinking Water Act (P. L. 93 - 523)

Clean Air Act Amendments (P. L 93 - 319)

Toxic Substances Control Act (P. L 94 - 469)

Resource Conservation and Recovery Act (P. L. 94 - 580)

Oean Air Act Amendments (P. L 95 - 95)

Oean Water Act Amendments (P. L. 95 - 217)

Resource Conservation and Recovery Act Amendments (P. L. 95 - 509)

Solid Waste Disposal Act (P. L. 96 - 482)

Comprehensive Response, Compensation and Liability Act (Superfund; P. L. 96-

510)

Superfund Law

Safe Drinking Water Act Amendments

Oean Water Act Amendments

Oean Air Act Amendments

Source: Pulp and Paper 1992 North American Factbook, p. 77.

27
Another industry trend is increased use of internal manufacturing waste streams and post-eonsumer

recycling, that complies with the various requirements at state and local levels (that can be different

from place to place) as to the level of recycling imposed by legislation.

All of these regulations will apply to new processes and products from biomass, and the awareness of

these evolving regulations is necessary so that programs are designed to help industry develop new

technologies that are environmentally sound and cost effective.

2.4Windows of Opportunity

Because of increases in demand, processing plant obsolescence, increased costs for environmental

compliance, and new technology development, windows of opportunity to commercialize new products

and processes in the chemical industry emerge every three to five years. In advance of these windows of

opportunity, new technologies must move from the laboratory and be demonstrated at sufficient scale to

reduce the risks for commercial introduction. The economic gain from exploiting a window of

opportunity can only be realized if the research has been supported well in advance of the need for new

technology. Several examples are presented to illustrate the diversity of characteristics that can

combine to create these windows of opportunity, followed by technical advances that promise to

contribute to expanding these windows into new applications.

2.4.1Example. Biodegradable Polymers

Currently, there exists a window of opportunity for developing and commercializing biodegradable

polymers. Technologies to produce and use polylactic acid, a chemical used in biodegradable polymers,

are examples of science and technology meeting an environmental and market need.

In the United States, almost half the current lactic acid market is supplied by a U.S. company that

manufactures lactic acid through a synthetic process. The remainder of lactic acid used in the United

States is imported from countries that produce lactic acid primarily by fermentation (HRA, Inc. 1991).

In this case, lactic acid produced synthetically is more expensive than that produced by fermentation.

As opportunities for increased use of biodegradable polymers emerge, the demand for lactic acid

increases. Rather than import lactic acid or increase production through the more expensive synthetic

route, the industry is building domestic plants that can produce lactic acid through fermenting sugars

derived from agricultural waste. This positive economic alternative is possible because government

sponsored research was conducted in the past five years to enable industry to take advantage of a

window of opportunity.

2.4.2 Example· Fast Pyrolysis of Biomass

Pyrolysis of biomass has been practiced for many decades for preparing charcoal, along with gases and

an oil. Only 100 years ago, wood pyrolysis was the source of chemicals such as methanol, acetone,

acetic acid, among others through wood distillation. The wood methanol along with coal tar phenolics

was the source of the first phenolic resins prepared by Baekeland (the bakelites).

Research and development in the field of biomass pyrolysis has, in recent years, developed an

understanding both of the science and of the engineering necessary to begin controlling the composition

of the fast pyrolysis products. Because biomass pyrolysis vapors are reactive oxygenated low molecular

weight chemicals, it was necessary to learn to form them quickly through a suitable fast heat transfer

mechanism, and also to remove them from the heated zone to avoid uncontrolled decomposition

reactions. The fast pyrolysis process is also called flash pyrolysis.

Controlling reaction conditions - high temperature, fast heating rate, and short residence timeallows pyrolysis products to be produced economically, moving the field to move toward technology

transfer and commercialization potential worldwide. Pyrolysis in the range of SOO-S50oC and within a

28
!

few seconds residence time, gives high (60-70%) yields of liquid products, that efficiently converted

into desirable products through a variety of post pyrolysis processes such as solvent fractionation,

catalytic processes, and post thennal cracking.

The control of the fast heating rate and short vapor residence time can be accomplished most readily in

three types of reactors: the entrained flow, the fluidized bed, and the ablative reactor (also called

vortex reactor); These reactors operate on scales from pounds/hour to hundreds of pounds/hour.

Pyrolysis experience at these scales is around thousands of hours of operation. Several engineering

groupsin industry and academia are using this technology. Their parallel developments and the start

of commercialization in companies in several countries indicate that the field is poised for

demonstrating and commercializing the most promising concepts. To this end, NREL has formed the

Pyrolysis Materials Research Consortium to exploit pyrolysis oils as components of phenolic-based

adhesives.

2.4.3 Example - Bioprocessing of Kenewables

New opportunities for large-scale bioprocessing will be driven by the need to competitively resolve

issues related to the environment and energy. Some of these opportunities include feedstocks for

degradable products (e.g., biodegradable plastics), oxygenated transportation fuel additives,

oxygenated chemicals, and "natural" or "green" products. Some large-scale bioprocesses have already

demonstrated significant advantages over existing technology where technology advances have been

successfully integrated. For example, the bioleaching of ores accounts for about 25% of copper produced

in the United States and constitutes a $650 million/yr business. Producing amino acids is now a $2 to $3

billion/yr industry, that developed through improvements in microbial strains and the fermentation

process. Com wet milling also utilizes fermentation and enzymatic conversion for producing ethanol,

high fructose com syrup, and other chemicals in an industry that produces more than $6 billion/yr in

revenue and utilizes 22.7 billion kg (SO billion pounds) or 12%-14% of the U.S. com crop (Datta 1992).

This latter industry represents an appropriate model for integrating commodity chemical or energy

production with specialized or intermediate chemical production through bioprocessing.

2.4.4 Examples- Technical Advances and New Applications

Barriers always exist to incorporating new technologies, however, in the case of renewables, most of

the technical barriers are incremental rather than "fatal flaws." The fundamental objectives are to

reduce feedstock costs, to increase product yields and rates, and to develop ways to separate products

efficiently and economically. Setting priorities for appropriate target product families and

technologies for the near-, mid-, and long-term is important. Such priorities cannot be determined

without industrial participation to provide insight into strategies for overcoming obstacles. Past

attempts by industry to produce chemicals from renewable feedstocks have failed due to lack of

adequate technology. Fortunately, there have been major advances in metabolic engineering, advanced

fermentation, reactor development and separations and fractionation technology that were not

available as few as five years ago. These advances can be used not only to exploit, but also to create

windows of opportunity. These advances can overcome some major technical hurdles and are applicable

to both bioprocessing and thermal and chemical methods for chemical production. They include:

• "Energy crops," such as varieties of sorghum, napier grass switch grass, or hybrid poplar

developed primarily for transportation fuels or power generation over the past decade could be

used as renewable feedstocks for chemicals. Some of these energy crops can produce 2 to 3 times

the biomass yields of the same crops that are conventionally used for food, feed, or fiber. Many

of them well known genetically and can be genetically designed and grown to produce different

amounts of lignin, protein, starch, cellulose, hemicellulose, or sugars. Different types of sugars

can alsobe produced.

29
.:

•

•

•

New separation technology for the high yield production of levoglucosan from biomass

pyrolysis has been developed. Levoglucosan, a derivative of glucose, has traditionally been

considered a high value specialty chemical. .New techniques for its isolation from pyrolysis

mixtures offers the possibility of this complex sugar being used as a feedstock for a variety of

applications.

New catalysis methodology is being developed for converting biomass derived materials into

useful products. This technology is being investigated for producing high value sugars from

simple starting materials such as glucose, sorbitol, mannitol, etc., as well as for preparing useful

chemicals from lignin.

Well developed methods for transferring DNA, the genetic material that controls biochemical

pathways, can be exploited to create novel metabolic capabilities. Examples include the

introducing two foreign genes into E. coli to produce a strain capable of converting sugars

primarily to ethanol, normally a minor product of E. coli metabolism (Ingram 1990), and

transferring of five bacterial genes into bakers' yeast to generate a strain that produces high

value colorants not produced at all by parent yeast (Ausich et al, 1992).

• Microbes currently used in industrial processes often are not well suited for genetic manipulation

using the standard tools of molecular biology. New methods have recently been developed for

introducing DNA into microbes, such as using electrical discharges or small projectiles coated

with DNA (Klein, et al. 1992). These approaches bypass the specificity that limits the use of

standard tools, and promise to transfer DNA into a wider variety of organisms.

• "Clean fractionation" technology for separating lignocellulosic material into its constituent

components offers a unique, cost effective source of cellulose, xylose, and lignin as raw materials

for chemical production.

• More efficient technologies for the pyrolyzing biomass are being developed to increase the

selectivity for converting renewables into useful chemicals.

;, • New strategies have been developed whereby introducing DNA into cells antagonistic to the

host's DNA alters the activity of a metabolic pathway (Cohen 1989). This approach has been

used, for example, to alter crops for controlling ripening and pigment production (Bramley, et al.

1992).

• Methods have been developed that greatly facilitate isolating and manipulating the genes

encoding individual enzymes (protein biocatalysts) that perform the stepwise conversions of

metabolic pathways. In particular, the polymerase chain reaction <PCR), permits the altering

of genes to generate specific changes in the structure of the protein they encode (Amheim et al.

1990). Altering proteins has been exploited to generate enzymes that perform novel reactions of

industrial use (Wilks et al. 1992). Alternatively, an enzyme can be engineered to function in a

different environment, for example in an organic solvent (Gupta 1992).

• Developments in fermentation and bioreactor technologies have been designed that enable

immobilizing microorganisms with a 100- to 1,OOO-fold intensification of microbial biomass, and

result in a concomitant increase in rates. Fluidized-bed reactor technology is being used for the

simultaneous fermentation and separation of lactic acid (Davison and Thompson 1992), and

producing ethanol <Davison and Scott 1988). A Significant improvement in retention time (five

minutes rather than several hours) was achieved when fluidized bed reactors replaced

conventional activated sludge systems in removing benzene, toluene, and xylene (BTX) from

waste streams (Frank 1992; Hickey and Owens 1981).

30
• Electrodialysis-based separation processes with novel bipolar membranes have produced acid

and base from salt using low amounts of power. This enables the recovery and purification of

organic acids from dilute, impure broths without creating a salt by-product. This advance is

being exploited to commercialize new lactic acid technology for biodegradable plastic

production (Datta 1989, 1992; Glassner and Datta 1990). Other advanced separations

technologies including adsorption and extraction, and reversible chemical complexation are

also available to replace distillation or precipitation.

2.5 Overview of Key Industrial Sectors

The Alternative Feedstocks program is closely related to how several industrial sectors operate,

including the chemical industry, the petroleum refining industry, and the renewables industry. Because

of this close relationship, it is important to outline the nature of these industries and some of the

challenges they face in the future to best direct the program to their needs.

2.5.1The Chemical Industry

The chemical industry is one of the most critical in the United States from several perspectives,

including industrial and military security, quality of life (Szmant 1989), and balance of trade

(Chemical and Engineering News 1991).

In 1992, 632 billion pounds of the top (in terms of level of Production) 50 chemicals were produced in the

United States (Chemical and Engineering News 1992); these were the same levels of production

achieved in 1990, and a modest 1.4% growth over the 1989 production. Of those, producing inorganic

chemicals accounted for 408 billion pounds. The chemical industry also employed 946,000 people, that

accounts for about 5% of all domestic manufacturing jobs(Chemical and Engineering News 1991). Since

1980, the chemical industry has enjoyed a trade surplus of $138 billion during a period when overall

United States trade has accumulated a deficit of more than $1 trillion. The 1991 trade surplus in the

chemical industry of $18.8 billion is second only to the $27 billion trade surplus of aircraft

manufacturers (Chemical and Engineering News 1991). However, the trade surplus for 1992 declined to

$16.7 billion (Chemical and Engineering News 1993).

The top two organic chemicals produced in 1991 were ethylene and propylene at 39.2 and 22.0 billion

pounds, respectively, with ethylene production showing a 7.5% increase from the levels of 1990.

Overall, production of the top thirty five organic chemicals in 1991 was 224 billion pounds, up slightly

from 219 billion pounds in 1990. Many of these organic chemicals were employed in manufacturing

roughly 63 billion pounds of plastics. Oxychemicals, a chemical industry segment also targeted by this

program, represent about 20% of this market (Szmant 1989). Paints and coatings represented 1 billion

gallons of production whereas the number of units of aerosol products consumed declined to 2.8 billion.

Pesticides stalled in growth with 1.1 billion pounds. Fertilizer consumption was down for all but

nitrogen-eontaining compounds, with a total of 40.6 billion pounds. Agrochemicals used by the

renewables industry are a major sector of the chemicals industry.

Table 2.3 compares the overall value of shipments of the chemicals and allied products sector to other

selected manufacturing sectors of relevance to this report. Interestingly, the value of shipments has so

far been able to weather the volatility of petroleum feedstock prices, which have varied by as much as

a factor of four from the seventies to the peaks of 1980-1982 (Table 2.4). Over the period 1981 - 1991, the

value of the chemical and allied products industry has been steadily increasing, demonstrating the

robust nature of this industrial sector. However, a large and unexpected increase in petroleum feedstock

prices, such as that experienced in the mid-1970s, could change this trend. .

The chemical industry faces several challenges in the future. Despite the strength of the U.S. chemical

industry, there are signs that foreign companies are strengthening their competitive position.

Contributing factors to this outlook include the declining crude oil production and associated refining

31
capacity in the United States, the increasing dominance of OPEC nations in petroleum markets, and the

increasing environmental regulations in the United States. The resulting massive structural changes in

the United States petroleum refining industry will have a definite impact on refined feedstock supply

sources for the chemicals industry (Osten and Veno 1991).

Table 2.3 - Shipments from the United States ChemicalIndustry by Relevant Sectors

Sector Value of Shipments (Billions of $)

1981 1985 1m 1990 1991

All Manufacturing Industries 2017 2279 2611 2917 2863

Chemicals and Allied Products 180 197 240 285 288

Petroleum and Coal Products 224 179 124 179 167

Rubber and Plastic Products 53 71 91 92 93

Paper and Allied Products 80 93 124 129 122

Source: Chemical and Engineering News,June 29,1992, p. 48

Table 2.4 - Selected Prices in Constant 1990Dollars for Primary Petrochemicals (cents/gallon)

Year

1972

1975

1980

1985

1990

1991

Methanol

28.28

79.83

108.94

51.58

38.50

48.52

Ethylene

9.19

22.18

37.44

18.08

21.50

18.58

ProRYlene

7.92

17.74

27.62

18.08

14.25

14.07

Butadiene

29.98

44.35

49.10

35.28

28.50

15.53

Benzene

5939

188.49

253.18

175.49

130.00

101.90

Toluene

65.04

137.04

191.80

143.48

100.00

82.98

Xylenes

67.87

121.96

168.79

147.03

95.00

82.01

Source: Chemical Economics Handbook, SRIInternational, 1992.

Competition by developing countries that have ample petroleum and natural gas resources has been

increasing in recent years. These countries now produce not only crude oil for export, but have also

moved into producing primary chemical building blocks, and commodity products derived from these

building blocks (Szmant 1989; List 1986). For example, Saudi Arabia has become in just a dozen years a

large-scale producer of methanol, polyethylene, styrene, ethylene glycol, ethylene dichloride, vinyl

chloride monomer, polyvinylchloride (PVC), ethyl alcohol, methyl tert-butyl ether (MTBE), and ;~ ~I

other chemicals (Szrnant 1989). Even though fixed capital costs are about 20% higher in Saudi Arabia

than in the United States, low feedstock costs can allow Saudi Arabia to compete in product areas

where feedstock cost is an overriding factor in other countries (Lee 1990).

The basis for the current United States competitive edge in chemical manufacturing over countries using

inexpensive feedstocks is the low-cost incremental expansion of existing facilities compared to building

new plants from scratch. However, as incremental expansions become limited by capacity, or

environmental or social constraints, new plant construction will increasingly take place overseas where

less expensive feedstocks are available. This pattern has been documented in the case of MTBE, that

has experienced strong market growth in the past three to four years. However, the marginal economics

of constructing new methanol (GRI1991) or butane plants in the United States suggests that much of the

new capacity will be built in other countries. These trends indicate that U.S. companies are

increasingly concentrating on high-tech specialty chemicals at the expense of intermediate and

commodity chemicals (Szmant 1989).

A reduction in domestic manufacturing of intermediate and commodity chemicals with increased

reliance on imported refined feedstocks or petroleum-based products (e.g. plastics) is indicated as

United States petroleum feedstock costs continue to rise, domestic oil production decreases, and oil

32
imports increase from 40% (1989) to 66% (expected 2010, GRI, 1991). Environmental regulations in the

United States are expected to further exacerbate this situation. For example, it is estimated that if

two key provisions of the Resource Conservation and Recovery Act (RCRA) were to be strictly applied

to the U.S. oil and gas industry, 8 out of 10 wells producing in 1991 would be shut down, 2.5 billion

barrels in oil reserves and 10.2 quads of recoverable gas reserves would be permanently unrecoverable,

and 148,655 jobs would be lost (API 1991). These trends are expected to continue and will lead to

increasing foreign competition in the chemical industry as incremental capacity is consumed, current

local feedstock reserves diminish, and regulation continues.

The trend toward increasing petroleum imports also directly affects the chemical industry with respect

to energy use and potential energy savings. The total industrial energy demand is projected to grow from

242 quads in 1989 to 32.2 quads by 2010 (GRI 1991). The chemical industry alone accounts for about 25%

(or 5.6 quads) of industrial energy consumption; the industry grewat an annual average rate of 6.6% per

year between 1986 and 1989. Petroleum accounts for 3.9 quads, natural gas, 0.6 quads, and coking coal, 1.1

quads (GRI, 1991). Total industrial petroleum feedstock consumption is projected to grow from 3.9 quads

in 1989 to 52 quads in 2010 and accounts for more than 80% of the growth in petroleum consumption of

feedstocks between 1989 and 2010.

These observations suggest that using renewable feedstocks in the raw material stream of the chemical

industry would be in the best interests of the United States. A number of factors support this:

•

•

•

•

The chemicals that can be made from renewable feedstocks comprise a significant portion of the

chemicals industry, and windows of opportunity for commercialization of some of these

chemicals are within a favorable 5 to 10 year timefrarne.

The bioprocessing industry is rapidly developing new technologies (section 2.3.4) that can now

be applied. Novel thermal and chemical technologies are also available for more selective

feedstock conversion.

Using renewable feedstocks and local processing can increase jobs, sales, and infrastructure in

the agriculture industry.

The prospect that the United States can lead the way in the "greening" of the chemical

industry by producing environmentally acceptable products using domestically grown feedstocks

in U.S. based chemical production facilities. .

Chemical facilities using renewable resources can provide flexibility because refining capacities and

corresponding capital investments are estimated to be roughly an order of magnitude lower than

equivalent petrochemical plants. In general, plants based on renewable resources range in capacity from

22.7-136.0 million kg/year (50-300 million pounds per year) or less (Szmant 1986) compared to

petrochemical plant capacities of 18Q..1800 million kg/year (4Q0-4000 million pounds per year, Bond

1990) as a result of differing economies of scale. A notable exception are large pulp and paper plants

that can be 3 - 4 times larger than typical renewables-based plants. In addition, biomass conversion

technologies could be integrated with existing facilities to provide feedstock flexibility for

functionally similar product lines.

2.S.Ll The Petrochemical Industry

The petroleum refining and chemicals and allied products sectors are closely linked to one another.

These dose interrelationships between sectors can be described, in a simplified way, by the diagram in

Figure 2.2, that shows how producing chemicals relies on the availability of refined feedstocks from

the petroleum industry. Of course, the petroleum industry relies on the availability of crude oil

feedstocks. In addition, the chemical industry uses a considerable amount of petroleum and natural gas

as fuel for their operations.

33
The basic building blocks of the chemical industry, methane, methanol, ethylene, propylene, butanes,

butenes, butadiene, and thearomatics benzene, toluene, and mixed xylenes, are derived from petroleum,

natural gas and natural gas liquids (two- to four-carbon hydrocarbons) via refining of petroleum

through thermal or catalytic processes. For most of the downstream organic chemicals manufactured,

these few primary building blocks are sufficient. Table 25 summarizes the specific primary source of

these building blocks.

These few primary petrochemicals serve as starting materials for a huge array of end products. As a

single example, consider the wide variety of products produced by the plastics industry (Figure 2.2).

General classes of products are plastics, fibers, and elastomers. Plastics are a particularly important

component of the economy, and are the only commodity to show an increase in its growth index (4%) for

the period 1990-1991. In comparison, chemicals and related products showed no growth, while the

total manufacturing sector decreased by 3% for the same period. These products (Figure 2.2) penetrate a

wide variety of end uses, summarized in Table 2.6.

Basic

building

r

FEedstocks

Petroleum

Natural Gas

Feedstock

Refining

Methane

Ethylene

Propylene

Butanes --....

Butenes

Butadiene

BTX

Chemical

processing

into

products

I

..-

Packaging

Building/Construction

Electrical/Electronic

Furniture/Furnishings

Consumer/Institutional

Transportation

Industrial/Machinery

Adhesives/Inks/Coatings .' ?

User, Industry

and Consumer t---t

Products

...-

Single -{POlyethylene

step Polypropylene

Polystyrene

Nylons

Phenolics

Polyesters

Acrylics

Others

Plastics/

chemicals

Figure 2.2 - Scheme of the Chemical and Allied Products and Petroleum Refining Industries

Only about 15-20 key types of plastics, along with wood and renewables-derived materials, make up

the bulk of the nonmetallic materials used in these applications. The importance of organic chemicals

derived from primary feedstocks to the plastic industry is obvious; of the 219 billion pounds of the top

thirty five organic chemicals produced in 1990,most were employed in manufacturing roughly 63 billion

pounds of plastics, including:

8 billion pounds of synthetic fibers (acrylic, nylon, olefins, and polyesters)

2.1 billion pounds of synthetic rubbers

6.4 billion pounds of thermosetting resins (epoxy, melamine, phenolic, polyester, and urea)

47 billion pounds of thermoplastics (polyethylene, polypropylene, styrene polymers,

polyamide, vinyl resins, and thermoplastic polyesters).

34
Table 2.5 - Source of Primary Petrochemicals in the United States (1990)

Source

Natural Gas

Natural Gas Liquids

and Refinery OffGases

Petroleum

Coal

Percent

8.2

38.0

53.0

0.8

Product

Methanol

Ethylene

Propylene

Butadiene

Aromatics

Ethylene

Propylene

. Butadiene

Benzene

Toluene

Xylenes

Methanol

Benzene

Toluene

Xylenes

Percent Made From

Source

95.3

71.0

68.0

48.0

very low

29.0

32.0

52.0

99.6

99.6

99.6

4.7

1.6

0.4

0.4

Source: Chemical Economics Handbook - SRIInternational

Table 2.6 - Selected End Uses of Plastic Products

General Use Area

packaging

building/construction

electrical/electronic

consumer/institutional

industrial/machinery

transportation

others

Examples

containers, coatings, foams, flexible packaging, films

pipe/fittings, interior/exterior materials, air-supported structures

appliance, communications, business machines, records, tapes,

batteries, furniture/furnishings: carpets, wall coverings

disposable food serviceware, photographic equipment, luggage,

lawn and garden, toys, sporting goods, cleaning products

signs, farm and construction equipment, machine tools, engine parts

land-, water-, and air-based for civilian or military applications

adhesives, inks, coatings, textiles

Other significant product classes are also derived from primary petrochemicals and include solvents,

surfactants, coatings, aerosols, pesticides and fertilizers.

The plastics industry is but one component of the nation's chemical output that could suffer

severe economic impact in the event of a significant increase in the price of the key primary

feedstocks, crude oil and natural gas. Incorporating domestically available renewables into

this supply stream could provide an important buffer to such a price increase. By developing

new technologies for products and processes, indigenous supplies of selected chemicals could be

made. In addition, reneuiables-derioed materials could complement current plastics and offer

environmentally acceptable strategies to a variety of packaging products.

35
2.5.2 The Renewables Industry

For this analysis, the renewables industry includes forestry and forest products as well as agriculture

and related products. Therefore, renewable industries represent a large segment of the United states

economy. Only a small fraction of their output is directed towards producing chemicals (starch

chemicals, cellulose esters and ethers, lignin chemicals, lubricants and additives), but the sector is

active in housing and furnishings by virtue of the wide array of inexpensive commodities it produces. In

1989, the farm income in the United States was $159 billion (473% crops, 52.6% livestock/products)

using more than 2.2 million farms and nearly 990 million acres. Government payments amounted to

$10.9 billion (6.8% of the farm income).

The United States has vast supplies of diverse renewable resources that are available for converting to

many different chemicals. The Department of Agriculture has projected that the U.S. feed grain (corn,

sorghum, oats, barley) production will increase by 14 percent to 249 million tons in 1992-1993, and the

domestic share of the world market will increase by 3% to 56% during 1993 (USDA May 1992). The U.S.

sugarindustry projects a 1993production of 7,500,000 tons of raw sugar, that is a 4.2 percent increase over

1992 (USDA June 1992b). Hawaii alone produced approximately 800,000 tons of raw sugar and 220,000

tons of molasses in 1990 from the cane sugar industry, although their share of the market is decreasing

(Hawaii Sugar Planters' Association 1991).

Using US. agricultural products as feedstock for chemicals and materials would benefit the nation by

supplying a new industrial market for agriculture, an industry that often produces more than it can sell.

This has resulted in acreages of 30 million hectares (or 74 million acres) or more, that are set aside

through payments to farmers in payment in kind programs (PIK, Frank and Smith 1986;Szmant 1986).

An opportunity to use some of this surplus, in place of imported petroleum, could have major benefits

that address goals in the National Energy Strategy, such as achieving greater energy security through

increased fuel and feedstock flexibility and use, waste minimization, and increased process efficiency.

This program would help energy security by shifting the feedstock. from petroleum to renewable

(domestically grown) resources. It would also reduce net C02 emissions and enhance environmental

quality by making environmentally compatible products such as "green" solvents, biodegradable

plastics, or other petrochemical substitutes.

The pulp and paper industry is a vital component of the renewable feedstocks industry. Shipments of

the paper and allied products industry in 1989 totalled $131 billion to provide 157 billion pounds of

paper and paperboard products made from 122billion pounds of wood pulp in 1989. The sector decreased

its shipment values from the peak in 1989 (see Table 23) as the industry installed increased capacity in

the United States at a time when the economy was taking a downturn, however, the volume of products

continues to increase. This is not unusual; most sectors of the renewables industries are currently

depressed because they are linked with the construction industry and the overall economy of the nation.

They could be revitalized by adding new crops and products, that would increase regional economic

development through increased employment.

In contrast to petroleum derived materials, the average price of the paper and paperboard products has

had a much smaller volatility over time, with the range over the last five years (1985-1990> being

$0.2~$O.24/poundof composite product. Indeed, using a renewable resource could provide a much more

stable indigenous basis for commodities and chemicals. It already contributes a very significant

fraction of our commodity materials for the same types of applications that the plastics currently hold,

but with heavier emphasis on the housing and furnishings sectors.

Renewable feedstocks add flexibility as starting materials for the huge array of end products

currently produced by the nation's chemical industry. It is necessary to identify the most

promising from a technical, economic, and market point of view.

36
2.5.2.1 Chemicals and Materials Currently Produced from Alternative Feedstocks

The use of renewable resources for producing industrial chemicals and materials today can be

characterized by two types of activities: first, integrating processes for the maximum use of products,

byproducts, and incidental wastes of the primary economic activity, and second, using a specific crop for

producing industrial chemicals and materials.

2.5.2.2Integrated Processing

The renewable industry can integrate food, chemicals, feed, and fuels, to allow a swing of products

capability that maximizes the industry's economic activity. For example, the forest products industry

supplies lumber and pulp for manufacturing solid wood and composite products, paper and paperboard

(Figure 2.3, Szmant 1986). By-product use developed an industry that converts some pulping liquors into

specific chemicals such as inexpensive lignosulfonate surfaetants and dimethylsulfoxide or using tall

oil for products. Incidental wastes such as bark became, in part, a source of chemicals such as tannins.

Many wastes became feedstocks for additional products or energy.

The corn industry produces food (com, oil, cereals, sweeteners, spirits, etc.), feed (gluten, meal,

distillers dried grains with solubles), starch-derived chemicals and materials (for paper sizing and

adhesive applications, plastics), ethanol fuel, and other products <Figure 2.4). Meat, milk, and cereal

grains processing has led to the developing adhesives from casein (milk), foundry resins from furfural

and furan (from oat!com cobs and other residues), fat by-products, and other materials.

Most other food processing industries, including apple juice plants, bean canneries, and potato

processors, have not achieved high levels of economic efficiency. Streams high in starch and sugars are

discharged into sewers, incurring BOD (biological oxygen demand) charges from the local municipality

because these streams may overload sewage treatment plants (Leeper et al. 1991). Waste minimization

is now a goal of food processing plants (as it is for most U.S. industries), and some have already

converted their "waste" streams to coproduct fermentation feedstocks. The Alternative Feedstocks

program can advance technologies that will provide these industries with a choice of fermentation

products. The most common alternatives are low value fuels such as ethanol and methane (fuels not

included in the scope of this program). A more attractive alternative is producing higher value

chemicals, such as organic acids, that can be made in significant amounts (relative to their total market

size) from these feedstocks, and produce a higher return on the investment.

.2.5.2.3 Use of a Specific:Crop for Producing Industrial Chemic:als and Materials

The natural fiber industry, based on cotton, cotton byproducts (cotton linters) and seeds produces oil,

meal, fatty acids, and soaps (Figure 2.5, after Szmant 1986). Chemically modified wood pulps

converted to rayon and acetate, wool, and cotton account for nearly half of the textile fibers produced.

These fibers have experienced heavy competition from the inexpensive synthetic fibers. In many areas

the plant-derived fibers have remained competitive because of properties desired by the consumer.

Other examples are oil seeds, including rape, mustard, wallflower, nasturtium, and others, that lead to

oil-derived products such as fatty acids, fatty alcohols, glycerol, soaps, specialty fatty acids, and a

number of derivatives.

Important industrial chemicals derived from renewable resources are listed in Table 2.7.

37
Table 2.7 - Plant Matter Derived Industrial Materials and Important Intermediate Chemicals in the

United States

Current Production Plant Matter Conventional Plant Matter

Product (millions of tons) Derived (%) Product Cost ($Ob) Product Cost <S/lb)

Wall Paints 7.8 3.5 0.50 1.20

Special Paints 2.4 2.0 0.80 1.75

Pigments 15.5 6.0 2.00 5.80

Dyes 4.5 6.0 12.00 21.00

Inks 3.5 7.0 2.00 2.50

Detergents 12.6 11.0 1.10 1.75

Surfactants 3.5 ·35.0 0.45 0.45

Adhesives 5.0 40.0 1.65 1.40

Plastics 30.0 1.8 0.50 2.00

Plasticizers 0.8 15.0 1.50 2.50

Acetic Acid 2.3 17.5 0.33 0.35 ,. : Furfural 0.3 17.0 0.75 0.78 , Fatty Acids 2.5 40.0 0.46 0.33 ., Carbon Black 1.5 12.0 0.50 0.45

NOTE: Market share of plant matter represents both wholly and partially plant matter derived

products. The cost premium of plant matter based products is calculated based on the average

median costs of commercially available products in a given category.

Sources: Chemical Marketing Reporter; Chemical &:Engineering News; US. Department of Commerce,

"US. Industrial Outlook," Washington, DC; Chemical Week; The Carbohydrate Economy

Rawtimber

250 x 106 tons

Includes 15 x 106 tons

of waste paper

Wood........__

Paper

T

and paperboard, 65 x106 tons, includes

9 x 106 tons of inorganic chemicals, clay, starch,

Cac~ etc., and 1 x 106 tons of nonwood fibers

Bark ...

,

Tannins,

xylitol

W

+ood------.. Lumber, construction boards, poles, t posts, veneer, etc.

chips

,

Pulping •

Lignosulfonates: 21 x 106 tons,

Extractives: oleoresins, naval stores,

turpentine, rosin, tall oil

Sugars (hemicellulose): arabino- Dis I· ,.l, so vmg

galactan, 2 x lu- tons ul ,1.6 x 106 tons

Also: dimethylsulfoxide, formic, acetic P P1

acids, etc. ,

Cellulose

Figure 2.3- Interrelationships and Materials Flow for the Pulp and Paper Industry, 1986

38
_____~_~ 158.5 X 106 tons

biomass collected

71 x 106 acres harvested in 1979

out of 90 x 106 acres available;

yields: 109 bula (1972), 85 bu/a

(1969),62 bu/a (1961)

I

Stalks, stover,

300 x 106 tons

........__I-__----!~.. Usable Resiues

39.6 x 106 tons

Cobs

rain: 65% starch, 10% oil,

9.5% protein, 145% fiber

193 X 106 tons, ca. 50% of world

supply

Starch, 3.9 x 109 1b ,

Refinery Products, 10.8 x l09 lb

Immobilized

amylgluc:osidase

Corn syrup, 1.75 x ~06tons

Anhydrous

glucose,

400 x 106 tons

Immobilized

gluc:oseisomerase

I

Gluten

5 x l09 lb

t

Zein

Exports ...---.. 127 x l09 1b

.... .-~ Foodand feed

276 x 109lb

I

Steep liquor

234x 109lb

Phytic acid,

inositol Fennentations

High fructose

corn syrup, 2.65 x 106 tons (1981)

2.9 x 1091b, 42% fructose; 1.7 x 1091b for beverage industry

1.2 x 109 lb, 55% fructose

total,4.1 x 109 1b, 150/0 of sweetener market

Fructose or levulose

Figure 2.4 - Com Products Industry (after Szmant; data as of 1980, or as indicated)

39
Cotton-33%

Petroleum derived and

glass fibers - 52%

Rayon and acetate - 13%

Wool-2%

Total production of textile

fibers, 5.9 x 106tons -

Oil, 1.3 x 109 lb;

75% of world

supply

Fiber ..;...... Lint .., Textile

14 x 106 bales 2.54 x 106 tons Mills

Unters 0.34 x 106 tons

[

Exports 1.01 x 106 tons

Total 3.89 x 106 ons

Added to forest based

Seed. cellulose

6.7 x 106tons

1.75 lblIb fiber

Meals and hulls

(protein, 50-55%, and

hemicellulose; 2.97 x 106 tons

Residues............ 05 t/ha

13 X 106 acres

prodUCE

2.7 x 106 tons

of biomass

Soapstoek,

fatty acids

Figure 2.S- Cotton ProductsIndustry

40
3.0 AVAILABILnY, USE, AND COMPOSmON OF BIOMASS

3.1 General Overview

Adopting any industrial process that relies on a primary raw material necessitates that the raw

material be: available in sufficient (if not excessive) quantities to supply the demand for the end

product; and relatively inexpensive, because raw material costs make up a large portion (up to 70%) of

total production costs of high volume chemicals in mature processes. The availability of feedstocks

does not appear to be an issue; current data indicate that biomass-based feedstock materials are

produced in the United States in quantities great enough to supply raw materials for producing several

commodity chemicals (Leeper et al. 1991). There is also a potential for new dedicated production of

biomass crops based on the vast amount of available cropland in the United States (USDA 1987; USDA

1991). This is a strong advantage for the United States with regard to future competitiveness in a

global biomass-based chemicals industry. Much of the feedstock material available is inexpensive and

would be ideal for producing chemicals. However, several general issues must be considered.

The first issue is one of feedstock diversity. Biomass-based feedstock materials used in producing

chemicals can be obtained from a large variety of sources. H considered individually, the number of

potential renewable feedstocks can be overwhelming, but they tend to fall into three simple categories

(EG&G Idaho, Inc. 1981; Leeper et al. 1991): waste materials (e.g., food processing wastes), dedicated

feedstock crops (e.g., silviculture [agroforestry], short rotation woody crops or herbaceous energy crops

such as perennials or forage crops), and conventional food crops (e.g., corn, wheat, etc.). In addition,

these raw materials are composed of several similar chemical constituents, i.e., carbohydrates,

proteins, lipids, lignin, and minerals. Thermal or chemical processing of these materials is typically

accomplished by novel separation and conversion methodology (sections 4.0, 5.0), leading to chemicals

similar to those from conventional petrochemical starting materials. Bioprocesses focus on

microbiological conversion of fermentable sugars that are derived from these materials by thermal,

chemical, or enzymatic means to commodity and specialty chemicals (sections 6.0,7.0>.

Different sources of feedstock material are referred to according to their current usage. However, in

choosing a feedstock for a given product, it is important not to be diverted by semantic differences that

arise due to its current usage. For example, switchgrass grown on currently idle cropland for chemical

production would be considered a "dedicated crop". Com stover derived from existing com production is

considered a "waste product." Despite their categorization based upon current use (or non-use), both are

sources of biomass that are similar in cellulosic composition. H com stover were adopted as a feedstock

for chemicals production, then it would no longer be designated as a "waste" but as another product of

com agriculture. The entire com industry provides a good example of how a single agricultural

commodity can be developed into multiple valued products. This is clearly illustrated by com

processing plants, which are so well integrated that it is difficult to distinguish any primary products

from byproducts which is why the tenn "coproducts" is preferred.

Once a "waste product" is identified as having use, supply and demand dictates that its value will

increase; no feedstock is "free." The Brazilian ethanol industry provides an example of how dedicated

crops become coproducts (Maiorella 1985). The bagasse left after extracting the sugar from the cane was

originally treated as a waste. Later, it was burned to provide energy for distillation. Finally, it was

sold to other industries as a boiler fuel, making a significant contribution to the process economics. At

each step, the value of the bagasse increased.

Feedstock diversity leads to a key component of this program: feedstock flexibility. If the supply of

one feedstock. raw material inadvertently drops below demand level, a given process must be able to

adapt and substitute another raw material. Different biological or chemical processing techniques can

be used, depending on the feedstock currently available. For example, the main disadvantage of

lignocellulosic feedstocks from the standpoint of bioprocessing is that they are more difficult to process

into an acceptable fennentation substrate, because the biomass consists of cellulose, hemicellulose, and

41
,' ,

,

".'

lignin, complex polymers that are relatively difficult to break down into sugars readily metabolized by

microorganisms (Office of Technology Assessment 1984). This disadvantage is more acute from the

perspective of producing lower value biofuels as products; it may be less significant for producing higher

value chemical products. In addition, certain microorganisms can ferment cellulose directly to products,

that can make cellulosic biomass more attractive. Thermal or chemical technology could be useful in

pre-processing these feedstocks to fermentable sugars that could then be converted biologically to

commodity chemicals.

Conversely, bioconversion technologies could be used with feedstocks rich in starch, because they are

readily converted (by feedstock processing or selective separation technology) to fermentable sugars

(e.g., glucose, Figure 3.1>. Fermentable sugar is ideal as a generic feedstock for bioconversion processes

because it is easily converted by biocatalysts into many different chemicals (Leeper et ale 1991). In

addition, many feedstocks can be processed into this single generic material that can be used either in

chemical or biochemical processes.

A third issue is one of feedstock availability. Large scale use of biomass as a raw material requires

that dedicated feedstock supply systems (DFSS) be established, that would guarantee the resource,

increase employment for a wide variety of sectors (nurseries/farm, heavy machinery, fertilizer, plant

equipment, distribution systems), decrease our heavy dependence on imported oil and increase economic

development in rural areas in the United States. These developments would complement a higher

technology driven agribusiness in which renewable resources would play progressively more important

roles in the economy. Importantly, DFSS could avoid critical supply problems, such as those

experienced in California with their use of biomass agricultural wastes for electrical power generation.

Prior to the project, low, and even negative costs typified the feedstock. However, as the project began,

demand grew, feedstock prices soared, and a shortage of feedstock resulted (DOE 1993)

Earlier penetration of these processes using alternative feedstocks could be achieved by using specific

waste biomass resources. Waste materials could establish the proof-of-concept of these technologies

and pave the way for their adoption in the future, when the realization of the overall energy savings

of these routes could be achieved through the DFSS coupled with producing chemicals, fuels, and

electric power.

An ongoing DOE program, field managed by ORNL, is examining both short rotation woody and

herbaceous crops for biofuels production. The program is screening different species to identify the best

match between individual plant characteristics and the wide variety of soil types and geographic

regions where the DFSS could be established. Several important economic and environmental criteria

have been associated with this investigation. The crops being developed should be low cost, highly

productive, require low fertilizer and water inputs, and be generally easy to manage. The goalof these

activitiesis to reach a production cost for delivered biomass of $40/dry ton. Future work in the program

will scaleup to larger plots so that productivity can be measured more meaningfully. These larger

demonstrations will also lead to better cost estimates of this technology. Significant interest by the

private sector in DFSSwas demonstrated by the over 300 responses received to a Letter of Interest issued

by DOE through NREL in April, 1993.

Each type of energy crop exhibits its own advantages and disadvantages. Herbaceous crops require less

time to establish compared to woody crops, but this advantage is partially offset by the potentially

lower overall costs of the woody crop concept. Short-rotation trees, that represent a new type of crop

production system, carry greater risks in harvesting than herbaceous perennial crops, that employ

modifications of conventional forage production systems. The woody crops also require the willingness

of the landowner to dedicate his or her acreage to that use for six years or more, versus two years in the

case of herbaceous crops. The choice will ultimately depend on many factors, including the location,

soil diversity, and biodiversity needs of the United States. The biodiversity and ecosystem impacts of

large scale use of these crops is currently being evaluated by a joint Electric Power Research Institute,

OOE/NREL and Audubon Society "Biomass Roundtable" that includes utilities, land managers,

42
Com

.---. Starch-Containing Potato I---

Feedstock Raw Materials PotatoProcessingResiduals

Sorghum

Feedstock Raw Materials Starch, OtherPolysaccharide, - Containing Other JerusalemArtichoke

or Sugar-Based Materials Polysaccharides

Apple Pomace FermentableSugars

Beet Molasses -.,. (GenericFeedstock

---. Sugar-Containing - Cane Molasses Intermediate)

Feedstock Raw Materials Sugar Cane

Spent SulfiteLiquor

MunicipalSolidWaste Paper

Com Stover

Lignocellulosic Materials I - Cellulose-Containing Forestry/MillingResiduals

I Feedstock Raw Materials Sugar CaneResiduals

Silviculture

SwitchGrass

Figure J.t - Production of a Generic Feedstock Intennediate from Representative Biomass-Based Raw Materials

43
ecologists, environmentalists and technology developers. The results and final report of this roundtable

will be published shortly.

Because the various conversion processes use biomass components differently, the best feedstocks for a

specific product will vary. For instance, high moisture content feedstocks are more suited for

bioprocessing than for thermal conversion processes, that require drier feedstocks. Bioprocessing routes

will profit from a high carbohydrate content, balanced with a certain amount of lignin as a heat or

electricity source SO that the overall process will have a good energy balance. Energy balance is

defined as the energy content in the fuel plus electricity exported (from burning the lignin fraction, if

available) over required inputs of energy in the plantation, transportation, net chemicals used, product

distribution, and plant amortization (Lynd 1991). As is well known, in the current grain-to-ethanol

case, this ratio can be near or less than one, because of the high level of agricultural inputs required and

the lack of a lignin fraction for power or process heat production. In the case of ethanol from

lignocellulosics, this ratio approaches five, if the fertilizer inputs to the DFSS are low.

Models such as the Agricultural Resource Interregional Modeling Systems (ARIMS) have been used to

project land use for the established biomass applications (food, feed, and fiber) and are now being

modified to incorporate fuels and chemicals production along with electric power generation. From the

initial use of this model, it appears that sufficient land exists for fuels and chemicals production as

well as electric power generation, justifying the investment of RD&Ddollars in these various programs.

The models need to be refined to take into account the profit maximization that will drive farmers and

investors to these areas, as well as the local (county) levels of land use for food, forage, fibers, and the

new products, searching for the early market penetration and identifying potential partners for their

development in specific geographic areas.

For maximum feedstock use in a sustainable biofuels industry, the feedstock conversion plant should be

capable of handling multiple feedstocks, if not at the same time, on a block operation basis (several

months on one feed, then several months on another feed). For some woody species, the ability to

handle mixed wood species (e.g., poplars and silver maple from the same region) is desirable. The

ability to start testing conversion processes on suitable agricultural residues is a good way to

demonstrate the conversion technologies, and then evolve into dedicated crops for maximum energy

impact.

A final, and very important issue is one of feedstock cost. Large scale use of renewables for producing

chemicals requires a balance between two factors: producing biomass must be profitable enough for

growers to pursue, yet the cost to chemical manufacturers must be low enough to offer incentives for its

use.

The diversity of feedstocks available makes choosing a single price to use in process evaluation

difficult. Therefore, the feedstock cost used becomes process dependent. For the purposes of the

evaluations presented in this report (sections 4.0 - 7.0), a delivered cost of $40/dry ton has been chosen

for those processes that are based on lignocellulosic biomass. For processes based on "waste" material

(as defined above), a true cost of feedstock is estimated because a "waste" material's value will rise to

its market level once a use is found for it.

The value used for lignocellulosic biomass is based on research carried out on small demonstration plots

under the direction of the ORNL Short Rotation Woody Crops Program <Wright 1990), and has tried to

address the cost by including an extensive list of variables. These include projections on costs for site

preparation, herbicide and fertilizer use, planting, supervision, and maintenance. Current results from

existing plots show delivered costs between $42.57/dry ton for a location in the northwest United

States, to $54.45/dry ton for locations in the northeast. However, their results document that a cost of

$40/dry ton could be realized under attainable conditions.

44
The issue remains complex, even though a given feedstock cost may be considered reasonable in certain

applications. The number of different stimuli that can affect this cost are surprising. Water

availability, susceptibility to disease or drought, crop location, etc., are all additional issues that

could be considered. However, concern over a long list of "what-its" is also symptomatic of a process in

its infancy. Because no large scale biomass production and delivery system has been demonstrated, some

questions remain to be answered. Recently, ORNL has started preparing for much larger scale

demonstrations of dedicated feedstock production. The results of this project will help verify the cost

projections of the smaller scale experiments.

3.2 Characterization of Representative Feedstocks

In the last ten years, approximately 50 different sources of renewable biomass have been suggested for

use as alternative feedstocks for producing valued chemicals (Leeper et a1. 1991). Sixteen of these 50

possibilities were selected as sample representative of families of biomass-based feedstocks (cellulose,

starch, free sugar, and inulin, another polysaccharide similar to cellulose and starch) that could

support chemical production (Table 3.1). These materials are alsodiversified according to their current

use, including materials that are food crops, sources of animal feed, waste materials, and materials

that currently have no significant use.

In addition, a summary of the availability of biomass wastes, that includes the agricultural residues,

was compiled by Alan Schroeder of DOE's Office of Industrial Technologies, Waste Material

Management Division. The list presents numbers of availability that correspond to 20% of the

agricultural residues that are expected to be economically recoverable. The wastes that were

considered of high priority because of their size and potential ease of recovery, and the energy savings

associated with those wastes are shown in Table 3.2.

Prices of representative raw feedstock materials range from $0.07/Ib for potatoes to almost negligible

levels for those feedstocks, such as waste paper and spent sulfite liquor, that make up waste streams

and are cunently liabilities for the industries that produce them (Table 3.3). All prices shown are low

when compared to the market prices of products that are under consideration, i.e., commodity and

Specialty chemicals; product prices range from $O.50/lb, for commodity neutral solvents up to $5.00/lb

for a specialty organic acid (Figure 3.2, Chemical Marketing Reporter 1992). Recall, however, that

once a "liability" is found to have a marketable use, its value will necessarily rise to the level the

market is willing to bear.

Production levels that are shown in Table 3.3 are illustrative of the vast and increasing amount of

renewables that are produced in the United States (USDA 1991; EG&G Idaho, Inc. 1981; Leeper et al.

1991). Also shown are levels of biomass supply that could be a part of a dedicated production of

feedstocks. For waste materials, dedicated levels usually equa1 all of the current supply. For crops,

dedicated production is that level that could potentially be reached using idle U.S. cropland.

Dedicated production levels for crops were calculated based on current yields for those crops, and idle

cropland available in regions that are suitable for their growth (USDA 1991; Bergez et a1. 1991;

Electric Power Research Institute 1991; Leeper et ale 1991). Potential dedicated levels of production

range from 0.8 million metric tons/year (1.8 billion lb/year) of potato processing residuals up to 742

million metric tons/year (1633 billion lb/year) of potatoes.

Dedicated production levels of crops shown in Table 3.3 are based on region-specific availability of

some or all of the 27 million hectares (68 million acres) of idle cropland in the United States in 1989

(USDA, 1991). The amount of idle cropland in the United States fluctuates on a yearly basis. In 1992,

there were approximately 22 million hectares (54 million acres) of idle cropland in the United States;

this amount could decrease or increase in 1993 based on the prevailing circumstances (USDA September

1992). At the present time, this land is part of the Conservation Reserve Program (CRP) and the

Acreage Reduction Program (ARP), both sponsored by the USDA. These programs control the use of

designated cropland, to protect the environment by regulating soil erosion, and reducing crop surpluses.

45
Table 3.1 - Representative Alternative Feedstocks: Primary Feedstock Constituents and Current Uses

Feedstock

Com

Potato

Potato processing residuals

Sorghum

Municipal solid waste paper

Corn stover

Forestry/ milling residuals

Sugar cane residuals

Silviculture

Switchgrass

Apple pomace

Beet molasses

Canemolasses

Sugarcane

Spent sulfite liquor

Jerusalem artichoke

Primary Feedstock

Constituent1

Starch

Starch

Starch

Starch

Cellulose

Cellulose

Cellulose

Cellulose

Cellulose

Cellulose

Sugars

Sugars

Sugars

Sugars

Sugars

Inulin

Current Uses

Food, animal feed, ethanol

Food, animal feed, ethanol (low level)

Animal feed, waste, ethanol (low level)

Animal feed

Waste

Waste

Waste

Waste, fuel

Proposed for chemicals

Proposed for chemicals

Waste

Animal feed, fermentation feedstock

Animal feed, fermentation feedstock

Food

Waste

Minoruse as food

IPrimary feedstock constituent = chemical component of raw material that will be used to derive

fermentable sugars for chemicals production.

Table 3.2- Recoverable Biomass Wastes

Millions of dry Millions of Trillion Btu

Recoverable Biomass tons Btu/ton totalsavin&s

Wheat straw and husks 2.5 14.2 35.9

Corn stover, cobs, husks 14.1 14.2 201.0

Rice stover and hulls 0.37 14.0 5.2

Barley straw 0.69 14.9 10.3

Sorghum straws 1.35 14.0 18.9

Orchard prunings 0.45 16.3 7.3

Feedlot manures 22.5 13.0 292.0

Cheese whey as dry waste 0.5 110.0 55.0 '

Potatoes processing wastes

(dry) 0.35 110.0 385

Waste woods and bark from

processing 3.0 18.0 535

Waste woods from in-forest

residue 35.4 17.0 601.0

Paper mill sludge 2.4 12.0 29.2

Corrugated cardboard 8.4 14.1 118.0

Waste newsprint 5.9 16.0 94.0

Waste printing/writing 11.6 10.5 121.0

Waste paper

packaging/brown paper 2.2 14.5 31.2

Waste boxboard, other board 3.5 14.1 49.1

Carbon dioxide 1000.0 0.04 40.0

Source: A. Schroeder, Waste Material Management Division, Office of Industrial Technologies, 1991

46
Table 3.3• Prices, Production, Potential Fermentable Sugar Yields, and Productivities of Representative

Feedstocks (United States)

Feedstock Price1 Production2 Yield3 Idle Land4 Dedications Sugar Yields6 Productivity7

Com 9 (4) 191 (421) 7294 (6513) 27 (68) 201 (442) 135 (297) 4.9 (4374)

Potato 16 (7) 17 (37) 32368 (28900) 23 (56) 742 (1633) 121 (267) 5.3 (4724)

Potato processing

residuals LTP 0.8 (1.8) 0.8 (1.8) 0.14 (0.3)

Sorghum 9 (4) 16 (34) 3474 (3102) 16 (41) 58 (127) 45 (99) 2.7 (2409)

Municipal solid

wastepaper LTP 95 (209) 95 (209) 74 (164)

Com stover None 105 (232) 52 (116) 19 (42)

Forestry/milling

residuals LTP 100 (220) 50 (110) 29 (58)

Sugarcane

residuals 4 (3) 3.6 (8) 3.6 (8) 1.9 (4.1)

Silviculture None - 9993 (8922) 27 (68) 276 (608) 154 (338) 5.6 (4956)

~" ,~ Switch grass None - 7392 (6600) 27 (68) 204 (450) 75 (165) 2.7 (2421) .. -.'

Apple pomaCE LTP 1.3 (2.8) 1.3 (2.8) 0.09 (0.2)

Beetmolasses 9 (4) 1 (2.3) 1 (2.3) 0.54 (1.2)

Cane molasses 9 (4) 1 (23) 1 (23) 0.54 (1.2)

Sugarcane 3 (2) 25 (56) 78176 (69800) (3.5) 8.6 272 (599) 114 (252) 32.9 (29371)

Spent sulfite liquor LTP 28 (62) 28 (62) 0.4 (0.8)

Jerusalem

artichoke None - 29120 (26000) 23 (56) 668 (1470) 111 (245) 4.8 (4328)

lPriCE of raw material, cents/kg (cents/lb); "LTP" =liability to the producer, and has negligible or no price;

"None" =the material is not currently a U.S. commodity; (Leeper et al. 1991;Salunkhe et al. 1991;USDA, 1991).

2Total annual U.S. production of raw material, metric tons x 1()6/year (billion Ib/year); (-) = not currently produced

as a commodity product; (EPRI, 1991; Leeper et aI. 1991;Salunkhe et al. 1991; USDA, 1991)

3For crops, kg/hectare/year (lbs/acrelyear); (-) is used for waste products, even those that are agricultural byproducts (because their supply is not dependent on land dedicated to chemicals production; sources of information

include Bergez et al., 1991; EG&G Idaho, Inc., 1981; Electric Power Research Institute, 1991; USDA, 1991.

4Idle cropland available within the U.S., hectares x 106 (acres x 10'); acreage for each crop was detennined by

totalling available aopland in those states where that crop is currently grown or could grow (USDA, 1991).

sProjected level of raw material production dedicated to chemicals production; based on availability of U.S. idle

cropland for that particular crop, metric tons x 1()6/year (billion Ibs/year); information concerning appropriate land

use based on particular crops, crop yields, and regional availability of idle cropland in the U.S.: USDA, 1991 (com,

potato, sorghum, sugar cane); USDA, 1991; Bergez et aI., 1991 (silviculture) USDA,1991; Electric Power Research

Institute, 1991 (switchgrass); USDA, 1991; Leeper et al., 1991; EG&G Idaho, Inc., 1981 Oerusalemartichoke); complete

dedication is assumed for waste materials; 50% dedication is assumed for com stover and forestry/milling residuals

because some ofthis material must be returned to fields as part of sound soil conservation practice (Leeper et al., 1991; .

Oak Ridge National Laboratory, 1991).

6Maximum potential yields of fermentable sugar based on dedicated production values of raw materials, metric tons x

106/year <billion lbs/year); sources of information that gave cellulose, starch, inulin, or sugar compositions of

feedstocks were Almosnino and Belin, 1991; Electric Power Research Institute, 1991; Leeper et al., 1991; Salunkhe et

al., 1991; USDA, 1991; Watson and Ramstad, 1987;Wayman et al., 1992-

7Metric tons of sUgar/hectare/year (lbs of sugar/acre/year); these are projected values derived from sugar yields.

47

Land that is designated as CRP- or ARP-committed is not available for extensive cultivating and

harvesting food, feed, and forage crops. However, there may be potential for this land for other uses

such as producing biomass feedstock with appropriate changes in legislation; this biomass could be used

for producing biofuels and chemicals. IfCRP- and ARP-committed land were used for biomass crops-(or

other crops), then appropriate measures would have to be taken to maintain sound soil conservation,

environmental policy, and increased biodiversity.

Dedicated production levels for raw materials were used to derive maximum theoretical fermentable

sugar yields. Values range from 0.09 million metric tons sugar/year (0.2 billion lb/year) for apple

pomace up to 154 million metric tons glucose/year (338 billion lb/year) for silviculture (agroforestry).

The amount of fermentable sugar that is derived from a particular feedstock is directly proportional to

the potential energy displacement (i.e . :displacement of petroleum feedstocks) for that feedstock in

terms of chemicals production.

A moderate production level of 13 million metric tons sugar/year (29 billion lb/year), which is

approximately a tenth of that potentially generated from dedicated com crops, could theoretically

supply 12 million metric tons (26 billion lb) of a single organic acid (based on a theoretical yield of 0.98

for a representative organic acid, succinic acid) or 5 million metric tons (11 billion Ib) of a neutral

solvent (based on a theoretical yield of 0.41 for a representative neutral solvent, butanol) from

appropriate bioprocessing technology. These quantities are much greater than current and projected

demands for these types of chemicals. The total potential sugar produced from switehgrass could yield

73 million metric tons (161 billion lbs) of an organic acid, e.g. succinic acid, or 31 million metric tons (68

billion Ibs) of a neutral solvent, e.g. butanol. Based on current production in the United States of 4.5

million metric tons (10 billion lbs) of total organic acids/year and 9 million metric tons (20 billion lbs) of

total neutral solvents/year (Leeper et ala 1991), the United States has enough raw feedstock material

to completely support producing many commodity chemicals (Figure 3.3).

Note that certain feedstocks may be particularly suitable for specific chemical products based on

projected production levels. For example, if 45 million kg (100 million lbs) is the desired single plant

output for a chemical, then a feedstock should be selected that will produce enough fermentable sugar

to meet this demand. Regional differences in feedstock availability will also affect feedstock

selection, e.g., if the proposed chemical production plant is located in the northeastern United States,

then a feedstock whose production is concentrated in that area should be selected (Oak Ridge National

Laboratory 1992). In any given chemical plant scenario, most of the 16 representative feedstocks could

meet the needs of a plant (because of feedstock flexibility described above), but there will be one or

more "best choices" based on required production level, regional considerations, and pre-processing costs.

Feedstock selection should be analyzed for individual scenarios; the top selections would be the

primary (but not necessarily exclusive) feedstocks used.

3.3Representative Alternative Feedstocks

Biobased feedstocks can be considered coproducts of agriculture and forestry, or their associated

processing industries. The United States' strong global position in these industries makes it a logical

leader in developing these feedstocks into chemicals (USDA 1987). As noted earlier, three broad

categories can be defined: "waste" materials, dedicated crops, and conventional food crops.

3.3.1 nwaste" Materials

3.3.1.1 Materials from Food Processing

The food processing industry produces a variety of coproducts that were formerly considered to be waste

streams (Levy et ala 1983; Leeper et ala 1991). Before World War II, a significant part of the United

States' chemicals industry depended on producing acetone, butanol, and ethanol by fermentation

(Linden et ala 1985; Maiorella 1985). The usual feedstock was molasses, a by-product of the sugar

49
100

90

80

·_·_·_····_····-i • OrganicAcidProduction NeutralSolventProduction f··....·· ..··..·....

70

60

MillionMetric Tons

of Product 50

perYear

40

30

20

10

o

From 1110

Dedicated

<.:om Crop

From Total

Dedicated

Switch Grass

Production

TotalCummt

us.

Production

From1110

Dedicated

Com Crop

FromTotal

Dedicated

SwitchGrass

Production

TotalCummt

U.S.

Production

Figure 3.3 - Projected and Current Domestic Produdion of Organic Acids and Neutral Solvents

50
industry. Since then, the growth of the chemical industry has not been matched by a corresponding

expansion of the sugar industry; consequently, the primary fennentation feedstock in the United States

for ethanol is now derived from other sources, e.g., com (Electric Power Research Institute 1991).

The modem com processing plant achieves levels of product integration that rivals an oil refinery

(Watson and Ramstad 1987). Corn oil, com starch, high protein animal feeds, com steep liquor, and com

syrup are produced. Some of the latter is fermented on site to fuel ethanol, and some is sold as a

feedstock for the biological production of chemicals such as citric, itaconic, and amino acids. A

projected 5%increase in fuel ethanol production from .com is predicted for 1993 (USDA May 1992).

Cheese processing plants can also show economic efficiency. Cheese whey, once considered a waste, can

now be processed to make a valuable whey protein concentrate and a sugar solution that can be

fermented to make fuel (ethanol or methane) (Leeper et aI. 1991; USDA 1980).

3.3.1.2 Materials from Cellulosic Biomass

The United States produces a large quantity of com stover (Elshafei et ale 1991; Table 3.3). Fifty

percent of crop residues need to be left in the fields to protect the soil from water and wind erosion, and

to recycle organic material <Leeper et at 1991; Oak Ridge National Laboratory 1992). Despite using

such recommended practices, there is still a large quantity of this feedstock material that is available

for producing chemicals. In fact, if a large portion of the stover not needed for soil conservation were

fermented to ethanol, it would satisfy a significant fraction of our demand for liquid fuels.

Forestry residues (including branches, wood chips, and sawdust) have a similar composition to

- agricultural residues, and can be used in the same way. There is a large supply of this material, so

diverting a fraction of these feedstocks to the biological production of commodity chemicals would

have little impact on their other current uses (Leeper et ale 1991). The biofuels potential from combined

agricultural and forestry residues is approximately two quads (Oak Ridge National Laboratory 1992).

However, using these residues must be consistent with sound soil conservation practices (Oak Ridge

National Laboratory 1992).

3.3.1.3 Dedicated Crops

Dedicated crops are those that are to be grown specifically to produce fuels, chemicals, or electric

power. The emphasis in selecting a suitable dedicated crop is on maximizing the rate of return per unit

area of land in an environmentally acceptable manner (Oak Ridge National Laboratory 1992). The

choice of a dedicated crop will vary according to geographic region, and ecological and other land use

considerations (Oak Ridge National Laboratory 1992). Examples include herbaceous oil crops, such as

soybeans, short rotation woody crops, such as poplar-based agroforestry (USDA January 1992; USDA

October 1992; Office of Technology Assessment May, 1991; Leeper et ale 1991; Bergez 1991) or switch

grass, napier grass and other forage-type crops that are native American species. Dedicated crops also

may include crops currently grown, as well as new crops, such as the Jerusalem artichoke, that show

particular promise as fermentation feedstocks (Leeper et al. 1991; Narayan et al. 1988; Manzoni and

Cavazzoni 1992). The most extensive examples of dedicated crops as feedstocks for a chemicals is the

Brazilian ethanol production program based on an immense crop of sugar cane (Maiorella 1985) and

their use of eucalyptus for charcoal production.

An important criterion in choosing a dedicated crop is the amount of energy in the form of fuel,

pesticide, and fertilizer required to grow it (Perlack et a1. 1992). If the necessary amount is high, then

the overall process may not achieve the goal of conserving energy. Total energy cycle analysis from the

crop generation stage through the industrial process, consumption, and emission stages are needed to

quantify energy conservation benefits. Production costs of crops, which are directly related-to the

amount of energy expended, are quite variable, ranging from $50/acre for barley to as high as $320/acre

for rice (USDA 1990). Additional information concerning energy balance and environmental impact

51
analyses of dedicated feedstock crops has been detailed as part of the Biofuels Feedstock Development

Program at Oak Ridge National Laboratory <Wright et al, 1992).

3.3.1.4 Conventional Food Crops

Another plentiful source of renewable raw materials is com. The total supply in the United States in

1986-1987 period was about 13 billion bushels, of which the projected domestic use was 5.5 billion

bushels. Exports constituted 1.1 billion bushels, leaving a surplus of about 6.4 billion bushels. Such a

com surplus represents the ability to make 227 billion pounds of starch, a remarkable number! The

worldwide trend is to increased grain self-sufficiency. The increased United States grain productivity

will lead to increasingly larger surplus grain production. Some of the com byproducts are primarily

sold to the European market. Changes in import levels for these products could greatly impact the

United States' export ability in this area.

This section overviews the makeup of com, and describes some of the products available when it is used

as a raw material. The first few tablesin this section overview the various components in com and com

byproducts. The composition of com is given in Table 3.4. Tables 3.5-3.9 present the composition of the

main products from com processing. Table 3.5 describes the protein content of the various parts of the

com grain. The com genn metal composition is descried in Table 3.6. Table 3.7 describes the oil

components of com oil, while Table 3.8 reports the average fatty acid composition of refined com oil.

Com hull (bran) compositions is assembled in Table 3.9.

Table 3.4- ComKernel: Composition of Parts (% Dry Basis)

Kernel

Endosperm

Germ

Hull

Tip Cap

Proportion of

Whole Kernel

100.0

81.9

11.9

5.3

0.8

Starch

71.5

86.4

8.2

7.3

5.3

Protein

10.3

9.4

18.8

3.7

9.1

Qil

4.8

0.8

34.5

1.0

3.8

Ash

1.44

0.31

10.1

0.84

1.59

1.97

0.64

10.81

0.34

1.61

Source: Earle et. al, Cereal ChemistJy,1946, 23,504.

Table 3.5· Protein in Com Grain Fractions (% of Total Nitrogen)

Nitrogen

Distribution Endospo::!ill Germ Hull

Nonprotein 2.0 1.2 3.4 7.7

Albumins 7.0 3.5 28.0 6.5

Globulins 10.0 2.5 24.0 11.8

Zein 39.0 45.8 5.0 4.0

Glutelin 35.0 38.0 30.0 12.0

Source: J.5. Wall and J. W. Paulis, Advances in Cereal Science and Technology, Vol. 2, Y. Pomeranz,

Ed., Am. Assoc. Cer. Chem., 1978

52
Protein

Starch

. Fat

Cellulose

Hemicellulose

Lignin

Ash

Table 3.6 - Com Germ Meal Composition (Solvent Extracted)

% DJy Basis

25-27

20

5.1

13

32

1

4.1

Source: S.A. Watson, Com Refiners Association, 1986 Scientific Conference

Table 3.7-Com Oil Components

,:l -.. .: ....

Triglycerides

Free Fatty Acids

Waxes

Phospholipids

Cholesterol

Phytosterols

Tocopherols

Crode Oil (%)

95.6

2.5

0.01

1.5

0.0

1.2

0.12

Refined Oil (%)

98.8

0.05

0.0

0.0

0.0

1.1

0.09

So~: Com Oil, Com Refiners Association, 1986

Table 3.8 - Refined Com Oil; Average Fatty Acid Composition

Palmitic (16:0)

Stearic (18:0)

Oleic (18:1)

Linoleic (18:2)

Linolenic (18:3)

Percent

11

2

24

62

1

Source: Refiners and Grooding, "Com: Culture, Processing, Products", G. E. Inglett, Ed., Avi., 1970

Table 3.9 - Com Bran (Hull) Composition

% 0Jy Basis

Cellulose

Protein

Xylan

lignin

Starch

Fat

Ash

23.0

7.5

42.1

4.9

7.8

3.2

0.8

Source: F. Hooper, Ind. Eng. Chern., 1942,34,728.

53
The key polysaccharide present in the kernel is starch. In starch, glucose units present a stereochemical

arrangement different from that of cellulose. Four hundred to one thousand a-D-glucose units (in the

pyranose form) are linked together by a-l-(1-4)linkages; this linkage yields the linear polymer,

amylose. Alternatively, 10,000-40,000 a(l-4)-linked and a(1-6)1inked glucose units yield the branched

polymer amylopectin. Starch is a non-structural carbohydrate that acts as energy reserve for the

plants. Because of the branched structures, access of the structures by enzymes is facilitated. Thus,

starch has been a traditional substrate for fermentation. Most of the common starches contain 17-27%

amylose; the remainder is amylopectin. Grains have been developed, however, with widely variable

composition. Properties and uses of industrial starches have been reviewed Oames 1974).

The key process for producing starches is com-wet milling. It can yield, on a dry basis, about 65%

starch, 5.5% gluten protein, 8% germ (oil, 4% and meal, 4%), 11.5% fiber, and 7.5% steepwater (Table

3.10>. The starch portion can be used for manufacturing modified starches, com SYrUP with a high

fructose content, dextrose, ethanol, and maltodextrins, as main products. The industry has a high

capability to swing from product to product with the ability to produce either syrups or alcohol

depending on the markets. Such flexibility is not present in the second most common processing method

for com, dry milling, in which ethanol and animal feed are the key products. The com industry is an

example of an industry that explores and uses byproducts to improve their overall profitability, much

like the petroleum refining industry.

A variety of starch products have been developed that are valuable in manufacturing paper products

(sizing products), textiles, foods, pharmaceuticals, building materials, etc. Starch also serves as the

feedstock for manufacturing a number of chemical compounds such as glucose, maltose, sorbitol and

ethanol. Starch is also the source of sweeteners such as high fructose corn syrup. Other parts of the

plant are also feedstocks for a number of products; furfural from com cobs is one example. The

composition of com cobs is illustrated in Table 3.11.

Dr. Morton W. Rutenberg (vice president, Research and Development, National Starch &: Chemical

Corp., Bridgewater, New Jersey) states that key to starch use is its chemical modification. Though

some of this modification can be accomplished genetically, it is still necessary to perform chemical

modifications. The modification enhances (or represses) inherent properties, or builds new properties.

Examples of major modification routes are crosslinking for increasing starch granule toughness;

hydrolysis to lower the viscosity of starch solutions (by reducing molecular weight); oxidation to reduce

molecular weight and increase the stability of solutions; esterification to stop retrogradation and lower

gelatinization temperature; etherification to introduce anionic, cationic, amphoteric, or hydrophobic

groups to starch; and polymerization to add functional properties through graft and block polymers.

Cationic starch ethers are used as additives for paper manufacture. Paper pulp is negatively charged

and the cationic starches neutralize the paper pulp and increase the paper production. There are,

however, competing cationic products that can be used in this application. Hydrophobic esters are

added to food products for forming emulsions and encapsulating food products. Using starch in grafting

and merging natural and synthetic polymers will still require research and development according to

Dr. Rutenberg. Many possibilities exist for extrusion cooking starch.

Other promising uses of starch as a raw material include synthesizing glycosides, that could be used in

urethane foams, but their cost may still be too high for competing with existing products. A number of

cyclodextrins (cycloamyloses) can be produced from starch, that can be used for enhancing wettability

and solubility, and could find uses in slow release applications. Glucose esters may be used as fat

substitutes. In addition, a number of plasticizer applications can be envisioned.

Protein fiber zein, present in the com, is also useful. It can yield fibers and form films. It is solvent

soluble and water insoluble. It is thermoplastic and resistant to hydrolysis and microorganisms, to some

extent. Many of these properties have been explored in producing textile fibers, in coatings of

pharmaceutical tablets, food, paper, varnishes, etc., and finally, in printing inks.

54
Steepwater:

Table 3.10 - MajorComponents of Com WetMilling Steepwater

Major Components

(Condensed Fermented Com Extractives; 40% - 50% Solids)

% Dty Basis

Nitrogen

As Protein (N x 6.25)

Lactic Add

Reducing Sugars

(As Glucose)

Phytic Add

Lipid

Phosphorus (Total)

Phytin P

Potassium

Magnesium

Total Ash

7.5

47

18-26

1G-20

7.8

0.4

3.3

4.5

1.5

15.7

"Peptides, Free Amino Adds, Ammonia Comprise 80% of Total Nitrogen

Source: S.A. Watson: Corn Refiner Association, 1986 Scientific Conference

Table 3.11- Com Cobs: Proximate Composition (% As Is)

Cob Woody Portion Pith/Chaff Portion

Cellulose 41.2 47.1 35.7

Hemicellulose 36.0 37.3 37.0

Lignin 6.1 6.8 5.4

Pectins" 3.1 3.2 3.2

Starch" 0.014 0.014 0.015

Lipids 0.041 0.028 0.081

Pentosans 34.6 36.5 34.7

" Xylan 30.0 31.6 30.1

a) Dry Basis

Source: Foley &: Vander Hooven in "Cereals: A Renewable Resource", Pomeranz &: Munck, Ed.,

A.A.C.C.,1981

3.4 Advantages and Disadvantages of Selected Renewable Feedstocks

Feedstock flexibility allows users of biomass to tailor their production to the feedstock that is

available as a function of season, geographical location, weather, etc. This section notes the

advantages and disadvantages of several readily available feedstocks of use to both bioprocesses and

thennal or chemical processes.

3.4.1 Feedstocks for Bioprocesses

Table 3.12 summarizes advantages and disadvantages for use of representative feedstocks typically

used in bioprocessing. All of the criteria listed are important when considering the suitability of a

55
particular feedstock for industrial level production of chemicals. Using the criteria shown in Table

3.12, an ideal feedstock material might have the following characteristics: minimal dependency on

crop hardiness, low price, minimal pre-processing (to a fermentable sugar) requirements, minimal

storage requirements, high sugar yield, chemicals production as a high value option compared to

current use (e.g, food, feed, fiber, or waste), high degree of technological advancement in producing and

processing raw material, and high efficiency in terms of environmentally acceptable land use.

The decision analysis of the "best" feedstocks for producing chemicals might be considered in the

context of near-term versus long-term goals. With respect to short term (0 - 5 years) adoption of

alternative feedstocks technology, the raw materials that currently have the greatest number of

positive aspects in the 16 samples assessed. are beet and cane molasses. These feedstocks share the

following advantageous properties: processing costs are low, because they are already in a fermentable

form; the technology base for using molasses as a fermentation feedstock is large; they are waste

materials (which means that they are not directly dependent on degree of crop hardiness and do not

directly affect land use); and they have minimal storage requirements. Chemicals production

represents a potential high value option for these feedstocks, and the conversion technology will

directly transfer to dedicated crops with similar fennentable sugars, such as sugar beets and sugar cane.

However, the uses developed will have to compete with various feed applications.

Although com does not possess as many positive attributes as beet and cane molasses, its well

established technical, industrial, and agricultural base could also make it a possible candidate. For

short term considerations, the feedstocks that have the greatest number of negative attributes in

relation to the other feedstocks are silviculture, switchgrass, and Jerusalem artichoke. These are

potentially disadvantaged from a chemical processor's view by lack of a significant technology base for

feedstock pre-processing or production.

With respect to long-term (10 - 15 years) adoption of alternative feedstocks technology, the raw

materials that have the greatest number of positive aspects are corn stover, forestry/milling residuals,

mumcipal solid waste paper, and sugar cane residuals (Table 3.12).

For long term scenarios, feedstocks were rated without considering pre-processing and technology base

factors, because problems in these areas would probably have been worked. out in 10 to 15 years time.

These feedstocks are good choices for chemicals production for reasons that include:

• chemicals production represents a high value option,

• supply does not have to be from land dedicated to chemical production

• raw material prices are low, and

• storage requirements are minimal.

The technology used for developing these feedstocks would also be directly applicable to the use of

dedicated. crops, such as silviculture and switch grass. For long-term considerations, the feedstock that

has the greatest number of negative attributes (in relation to the other 16 representative feedstocks) is

potato. Potatoes are primarily disadvantaged by the high cost of raw feedstock material in relation to

other feedstocks listed..

Recent technological advancements in sustainable farming/forestry practices and feedstocks preprocessing (to fermentable sugars) should improve the clarity of an already bright picture. Such

advancements include genetic engineering of crops, such as potatoes, to bring about an increase in dry

matter production (Salunkhe et al. 1991). Genetic engineering can also bring about increased crop

hardiness (Salunkhe et aI. 1991). By May 1991, the USDA and EPA had approved 236 field tests for

reviewing genetically modified. plants and microorganisms (Office of Technology Assessment 1991).

The Biofuels Feedstock Development Program at ORNL includes (among other projects) major efforts in

genetic improvement research for woody and herbaceous crops(Wright et al. 1992). One of the results of

this research program has been developing hybrid poplar trees that have greatly increased yield,

56
.\iiI

Table 3.12 • Positive and Negative Characteristics of Representative Feedstocks!

Feedstock Hardiness/ Price) Processing" Storage! Sugar Yield6 Waste Technology Land

Minimization" Base" Usage"

Com - +/- +/- + + - + - Potato - - +/- +/- + - + -

Potato processing residuals + + +/- - - + +/- +

Sorghum - -r- +/- + + - + -

Municipal Waste Paper + + - + + + - +

Com stover + + - + + + - +

ForestryI milling residuals + + - + + + - +

Sugar cane residuals + + - + + + - +

Switch Grass - +/- - + + +/- - -

Silviculture - +/- - + + +/- - -

Apple pomace + + +/- - - + +/- +

Beet molasses + +/- + + + + + +

Cane molasses + +/- + + + + + +

Sugar cane - +1- +/- + + - + +1-

Spent sulfite liquor + + + - - + - +

Jerusalem artichoke - +/- +/- +/- + +1- - -

'Sources are the same as those for Table 3.3, and Agr;cultur, 2000: A Lool ima 1MFutur" 1983. JCrop hardiness; (+) indicate" that supply of lhe raw material is not directly influenced by the success of a crop dedicated to chemicals production;

(.) indicates the raw material is derived from a crop that is dedicated to chemicals production; for example, the com crop that is referred to above would be one that was grown expressly for providing feedstock material for the production of

chemicals; however, the com stover supply listed above would be derived from currently existing com production (not dedicated to chemicals production); lhus, com stover is not directly dependent upon the success of a dedicated crop -- it is a waste

material that wil always be available in large quantities; even if exisling com production has a bad year, com stover "ill be available in large quantities, since current com production is very high (see Table 3.3). 'Price of raw malerials; (+)

indicates that the price is less than I centlkg; (+/-) indicates a current price (or probable price) of 1 10 10 centslkg; (-) indicates a price of greater than 10 centslkg (see Table 3.3). ·Level of pre· processing of feedstock necessary prior to utilization

as a fermentation substrate; (+) indicates lillie or no processing necessary; (+/-) indicates moderate level of processing necessary; (-) indicales extensive processing necessary. 'Storage properties. (+) indicates long-term storage possible; (+/-)

indicates medium-term storage possible, (.) indicates long-term storage possible only if costly storage quality criteria are met. 8Maximum potential fennentable sugar yield from dedicated production values of raw material; (+) indicates greater lhan

or equal to 0.54 million metric tons of sugar/yr, (-) indicates less than 0.54 million metric tons of sugar/yr; cutoff value is based on 0.54 million metric tons of sugar required 10 produce 0.27 million metric tons of a commodity chemical (al a yield

of 0.5) at 6 chemical production plants [based on 6 U.S. agricullural regions, (8auelle Memorial Institute. 1983); 0.045 million metric tons (l00 million pounds) of chemical/plant/yrJ (see Table 3.3). '(+) indicates usage of feedstock constitutes a

potential solution to a waste liability, or is a high value option for the material, (-) indicates Ihat the malerial is already a eommodity product, (+/-) indicates that the material is neither waste nor a commodity product. 'Level and success of research

and development associated wilh production and processing of feedstock . (+) indicates high level and success; (+/-) indicates medium level and success; (-) indicates low level, or high level but low success. 'Utilization of land for growth of

feedstock; emphasis is on reduction of environmental stress by using as little land as possible; (+) indicates that the material is nol derived from land dedicated 10 producing feedstoclts for chemicals production; (+/-) indicates a produclivity greater

than or equal 10 I to 10 metric tons sugarlhectare/year; (-) indicates a prcductivity.of less than 10 metric Ions sugarlhectare/year (refer 10 Table 3.3).

57
and thus exhibit greater potential as energy crops (Oak Ridge National Laboratory 1992). This was

developed by implementing hybridization and clonal selection, innovative physiology studies, and

crop management studies.

Recent research concerning pretreating cellulosic materials has positively affected the potential use of

those type feedstocks (Lynd et al. 1991; Teunissen et al. 1992; Wayman et al. 1992). In addition, the

U.s. Department of Agriculture has historically sponsored much research concerning advancing crop

generation. Because these research efforts directly address problems (e.g. fermentable sugar yield and

raw material pretreatment) which affect process cost sensitivity, taking advantage of the

opportunities that these types of recent technological advances present is a key component in the

development of a biobased chemicals industry.

3.4.2Lignocellulosic Feedstocks

In general, the composition of lignocellulosic feedstocks reveals common constituent polymers. Tables

3.13 and 3.14 summarize the chemical composition of several of the feedstocks described in this section.

Hardwoods could be an excellent raw material for bioconversion because of their availability and

desirable properties. Although some hardwoods are valuable and much in demand, many are

considered a silvicultural problem-because of their poor performance when compared with softwoods in

producing cellulose pulp by the pulp and paper industry. Often the trees are of small diameter and

without a usable trunk, and are therefore usually weeded from forests to make space available for

softwood plantations.

The advantages of using hardwood material for bioconversion include the high density of many species,

the relative ease of delignification and accessibility of the wood carbohydrates, and the presence of

only one hemicellulose, xylan, that can be more easily removed than softwood hemicelluloses. Other

advantages include low ash content, particularly silica, and slightly higher total carbohydrate and

cellulose content. The possibility of byproduct use is great, especially when compared to softwoods.

Hardwoods have a higher acetyl content than softwoods and most grasses and would yield more acetic

acid. Xylan conversion to furfural would produce a product with a potential market (Parker et al.

1983). The small amount of glucomannan hemicellulose could probably be converted together with

cellulose, especially if fermentation is considered.

Softwoods have considerable value as construction lumber and pulpwood, thus using this raw material

for biomass conversion might not be economically beneficial. However, the pulp and paper industry has

large amounts of logging and manufacturing residues that could serve as raw material for converting to

other materials, because they are normally unsuitable for use in normal cellulose pulp production.

Branches and tops constitute most of the logging residues. Because of the higher density of branch

wood, diffusion of pulping liquor into the cell wall is difficult. The probable presence of compression

wood in branches also is a problem because the higher and more condensed lignin content of compression

wood together with a thicker cell wall makes any adequate delignification difficult. Compression

wood also has a lower total carbohydrate content (especially cellulose), making it less desirable as a

raw material for pulp production. The tops of trees have many branches and may have considerable

juvenile wood in the main stem. Because juvenile wood has a low density and thin cell walls, it would

be overreacted before the branch wood could be adequately treated. Therefore, logging residues

probably are best used as a fuel source or could serve as feedstocks for thermochemical processes.

The primary manufacturing residues of the pulp and paper industry are debarking residues, sawdust,

and sanderdust. Bark, especially from thick barked softwood species, is not readily adaptable to nor

desirable for wood carbohydrate use. However, the need for suitable uses of bark is great and

developing chemical processes for its conversion to new materials is needed. In certain regions, much

more sawdust is produced than can be consumed in the pulping industry; often sanderdust is also

available. The primary impediment to their use is the type of lignin present in softwoods. Not only is

58
Table 3.13- Cell Wall Constituents of Biomass (%)

Normal Wood Softwoods Hardwoods Grasses Comments

Cellulose 41-43 43-45 35-393 aMay be higher

Lignin (average) 28 22b 16b "some soluble lignin

Range 24-33 16-24 15-18

Xylan (Pentosans) 8-14 (5-10) 20-30 (12-24) 27-34 (25-29)

Glucomannan 16-22c 305 None CContains variable galactose amounts

Compression Tension

Reaction Wood (Softwood) (Hardwood) Comments

Cellulose 32 56d dExcess in G layer

lignin 40 14

Xylan variable low

Glucomannan low low

Galactan" 8-16 0-8

: ." Table 3.14-Chemical Composition of Some Common Fibers

Chemical Component (percent)

Type of Fiber . Cellulose Lignin Pentosan Ash Silica

Stalk Fiber

Straw

Rice 28-36 12-16 23-28 15-20 9-14

Wheat 29-35 16-21 26-32 4.5-9 3-7

Barley 31-34 14-15 24-29 5-7 3-6

Oat 31-37 16-19 27-38 6-8 4-6.5

Rye 33-35 16-19 27-30 2-5 0.5-4

Cane

Sugar 32-44 19-24 27-32 1.5-5 0.7-3.5

Bamboo 26-43 21-31 15-26 1.7-5 0.7

Grass

Esparto 33-38 17-19 27-32 6-S

Sabai 22.0 23.9 6.0 --i

Reed

Phragmites 44.75 22.8 20.0 2.9 2.0

Bast Fiber

Seed Flax 47 23 25 5

Kenaf 31-39 15-19 22-23 2-5

Jute 45-53 21-26 18-21 0.5-2

Leaf Fiber

Abaca (Manila) 60.8 8.8 17.3 1.1

Sisal (agave) 43-56 7-9 21-24 0.6-1.1

Seed Hull Fiber

Cotton Liner 80-S5 O.S-1.S

Source: Rowell, R.M. in ACS Symposium Series, 476, p. 19, 1992

59
delignification more difficult than with hardwoods, but opening the cell wall structure and providing

access to the cellulose is more difficult. On the average, softwoods have less total carbohydrate and

slightly less cellulose than the hardwoods. The hemicellulose fraction is also more complex, with less

pentosan available for possible conversion to furfural.

Lignin use still presents the greatest challenge. Most prior lignin research aimed at using lignin .

involved softwood lignin, but hardwood lignin may have some advantages. Hardwood lignin is less

condensed, meaning it has a lower degree of polymerization and less carbon-carbon bonding. Hardwood

lignin also has less tendency to condense under acid or alkaline conditions. Hardwood lignin has a

greater methoxyl content, that in destructive distillation of wood resulted in more methyl alcohol

(wood alcohol), thereby malcing hardwoods preferred over softwoods. It may be possible to obtain

methyl alcohol from hardwood lignin without pyrolysis. Hardwood lignin becomes plastic at a lower

temperature than softwood lignin, that is the basis for using hardwoods in wood bending. Perhaps this

property could also be exploited.

The immediate use for lignin produced by bioconversion would be as a fuel because it has a much higher

energy value than wood. This byproduct lignin should be evaluated for use as a raw material for

synthesis gas formation. For higher quality use of lignin, some chemical modification, e.g., removing

aromatic ring substitution groups, such as methoxyls, without introducing another functional group

would probably be necessary. Potential markets for lignin use have been reviewed by Chum et al. (1985)

and by Chern Systems (1987).

Agricultural residues have an advantage resulting from their chemical composition. Because of the

amount and nature of the lignin present, grasses are easily delignified and the carbohydrates are made

readily accessible. Because the hemicellulosic fraction is closely related to xylans with no

glucomannans present, this also simplifies chemical conversion. Xylans are much more susceptible to

acid hydrolysis and alkaline extraction than cellulose and can be readily removed if necessary. The

technology is available for converting xylans to furfural, an industrial chemical used in adhesives and

resins and as a plasticizer. Corn stover (cornstalks) is unique and occupies a similar position among

agricultural residues as aspen does among the hardwoods. It has a lignin content of only 14% rich in

esterified acid groups, and has a xylan rich in both acetyl and uronic acids. Very mild treatment will

make the cellulose accessible. The availability of cornstalks for bioconversion, however, is limited

because of their competing use as silage.

A problem with agricultural residues is that the quantity available is only a small fraction of that

available from hardwoods. Also harvesting agricultural residues usually takes place within a short

time span once a year, necessitating that storage space must be provided for an annual supply.

Agricultural residues are quite susceptible to microbiological degradation, particularly when wet, that

can destroy their bioconversion potential in a matter of days. Most agricultural residues are best stored

under shelter, thereby adding to their cost and complexity of storage. Agricultural residues tend to be

bulky because of their low density, thus complicating transportation, handling, and storage, and

generally result in higher costs than for the same operation using wood. Digester capacity is greatly

reduced and the liquor-to-residue ratio substantially increased due to low bulk density. In the actual

processing, the high silica content of most agricultural residues may cause substantial abrasion and may

necessitate more frequent changing of cutting edges and operating down time due to equipment problems.

60
. \i

.1

4.0THERMAUCHEMICAL ROlITES TO PRODUCTS

4.1 General

Developing renewables-based technologies to produce both simple chemical building blocks and new

materials offers many new opportunities, and faces many challenges, as outlined in sections 1.0-3.0 of

this report. However, any new technology under consideration by the chemical industry, regardless of

the feedstock employed (renewable or nonrenewable) must meet important criteria: will the new

process be economically viable, and will it be advantageous to replace existing technology? A

preliminary overview of the potential of renewables suggests that hundreds, and perhaps thousands of

materials could theoretically be prepared from biomass (e.g., Szmant 1986) that makes selecting a few

promising opportunities for more detailed RD&D difficult. Additional reports support this conclusion

(Rowell 1992,USDA 1992) and yet not every opportunity makes economic sense. An intelligent analysis

of RD&:D opportunities requires an efficient, quantitative selection methodology, based on economic

considerations, because of the wide range of potential processes, catalysts, and products available.

A key component of the Alternative Feedstocks program has been developing such a comparative

selection methodology. This approach (described in detail in section 4.2) is being used to prioritize

options for a focused research start-up and to outline opportunities in three areas. First, near-term

opportunities that already appear cost-effective according to the available data are identified. These

chemicals or processes could lead to marketable products fairly quickly, and additional RD&D with

industry could expedite their penetration into the marketplace. Second, mid-term opportunities are

identified and include concepts that require additional RD&:D to provide experimental data to

validate the technoeconomic assumptions and demonstrate that yields/cost/properties are appropriate

for further engineering, development, and commercialization with industry. Finally, long-term RD&D

opportunities are identified and include developing research needs that underpin the science of

renewable resources. This effort is a necessary component of the overall program if the potential of

these resources is to be achieved for these purposes. Through scientific discoveries and this portfolio of

near-, mid-, and long-term opportunities the use of renewables could become a major contributor to

production of the country's fuels, chemicals, and electric power in the 21st century.

A unique feJlture of the Alternative Feedstocks program is a consistent, quantitative

methodology to identify new renewable primary building blocks (analogous to methane,

ethylene, etc.) that could serve in similar capacities and lead to new technology for preparing

known and new end products exploiting the uniqueness of biopolymers.

The DOE Separations Division of the Office of Industrial Technology funded NREL·to develop the

technoeconomic evaluation process to be used in this quantitiative analysis, and systematically screen

the wide range of products that could be produced from renewable feedstocks. For convenience, the

chemicals assessed have been divided into two categories: those available from thermal and chemical

processes (summarized in Table 4.1), and those available from biotechnological routes (summarized in

Table 7.1). Both biological and thermal and chemical processing routes are included in these

assessments since the catalysts used in thermal and chemical processes and the enzymes employed in

bioprocessing can lead to the true potential of chemicals from biomass in the near-, mid-, and long-term.

Interestingly, a systematic, quantitative screening methodology that considers yields of processes,

improvements in the technologies, and various feedstocks, had not been developed for using renewables

as chemical feedstocks. Most studies claiming to provide this infonnation were carried out by a variety

of process analysts and the various assumptions among them were not uniform. This study places

existing previous data into a new consistent methodology and begins a systematic evaluation of

chemicals and materials from renewable resources. As additional chemicals and materials are

identified as the program proceeds, the routes will be investigated using the same consistent

methodology, eventually leading to a database for uses of biomass available to researchers,

61
government managers and policy makers, and industrial researchers and managers, that will help

communities decide which routes fit their own unique needs and context.

The methodology developed is simple and thus of wide applicability. The initial screening simply

compares the raw material cost contribution of the proposed new process to the existing process (section

4.2). This comparative approach allows researchers and managers to be more aware of the current

methodologies and what is necessary for these new routes to penetrate the marketplace. Certainly,

improving conventional technology is an ongoing process and an alternative to introducing new

processes. Over time, the comparative order and costs of biomass and conventional processes could vary

as improvements and breakthroughs are made in existing processes. However, many conventional

processes are based on mature technology, for which most of the gains in process improvements have

been made. Under these conditions, those processes are dependent exclusively on the feedstock cost and

product market considerations. It is possible that renewables could penetrate some areas in which the

existing capacity has beenreached and increases could be considered at smaller size plants. Thus, the

other main difference between this study and previous ones is including market parameters and

globalization considerations in selecting targets for future RD&D with industry.

Renewables have not normally been considered as sources of end use chemicals. For this reason, a large

number of both short- and long-term research questions are being identified. To effectively address the

technology and basic science needs of the program as identified by this quantitative assessment,

Parallel research tracks will be recommended to leverage synergistic funding resources. The OOE/Orr

Separations Division will receive recommendations to support process development and improvement

using those materials for which a fairly well defined route exists (near term opportunities). Mid-term

opportunities will be recommended to the OOE/Orr Biological and Chemical Technologies Research

Program. This includes cases for which the use of a given feedstock as a starting material for products

traditionally derived from petrochemicals is unknown, or more extensive RD&D is necessary to bring a

material to market. A longer term basic research effort will alsobe undertaken to understand processes

and chemicals that show promise, but require a more fundamental understanding before being moved

toward a market application. This basic effort also includes investigating the more generic areas of

novel conversion methodology, separation chemistry, and new methods of using these materials.

A wide range of informational sources has beenused to help guide this assessment effort. A key feature

has been establishing an industrial panel for both the thermal and chemical processing and

bioprocessing elements of the program. This panel provides industrial input as to which feedstocks and

end-use products hold the greatest interest and potential for commercial application. The first meeting

of the industrial panel was held in February 1992 to develop an industrial perspective and suggest an

initial direction for the screening procedure. The industrial panel will also participate in reviews of

the opportunities identified for chemicals production and will continue to provide feedback on the

structure and direction of the Alternative Feedstocks Program.

Additional informational support for this technoeconomic evaluation has been provided by the

National Academy of Sciences (NAS) through their recently completed study entitled "Putting

Biotechnology to Work: Bioprocess Engineering." The objective of this study was to address key aspects

of research and commercialization of bioprocessing applied to the emerging families of food,

agricultural products, and industrial chemicals generated by biological routes that will require

innovative, world-class bioprocessing techniques for their manufacture. A committee of 12 experts

examined future bioprocessing opportunities in view of recent advances in biotechnology and the

chemical and material sciences. Workshops dealing with key research and commercialization aspects

were held to augment the information base of the committee. This report provides an authoritative

perspective on bioprocessing and a critical reference for future actions by government, industry, and

academia. The information gained through this NAS study will be incorporated into the analysis

planned for the Alternative Feedstocks program to select products and processes for focused attention.

The NAS is involved in a second study entitled "Biobased Industrial Products: National Research and

Commercialization Priorities." This study will follow a similar format to that outlined above. The

62
emphasis.of this study is on biobased materials and engineering for applications to both specialty,

high-value products and commodity, low-value materials.

Additional studies focusing on thermal and chemical processes have been conducted through a group of

volunteers during American Chemical Society meetings in Washington (1992) and Denver (1993). In

Denver, an international group was convened to discuss producing chemicals, fuels, and electric power

from renewables and policy implications worldwide. It is expected that a Biomass and Bioenergy

special volume will be published from the Denver meeting. This will be a valuable source of

infonnation for planning similar to that resulting from the 1990 Washington meeting <Rowell 1992).

4.2 Description of Screening Methodology for Thermal and Chemical Pracesses

The study started with the 70 most promising chemicals and materials that can be produced from

renewable feedstocks through thermal and chemical or bioprocessing processing routes (35 products

each). Sections .4.0 and 5.0 present the results of the quantitative assessment of thermal/chemical

routes to chemicals and materials. The results from the bioprocessing element of the study are

presented in sections 6.0 and 7.0. In the future, more candidates will be added to the screening process on

an annual basis. Upon completion of the screening of this initial portfolio of candidates, the most

promising feedstocks/products could be selected to begin further investigation in a multilaboratory

research effort with industry participation.

Although the methodology used to identify RD&tD opportunities is simple, its description is more

complex. Figure 4.1 overviews the approach schematically.

Initial 35

candidates

MateriaJJprocess n

classification

Economic n

assessment

.

i

Direct

substitution

Improved

production

Comparative raw material

cost contribution ratios

Near, mid, and. long term

R&D opportunities

New building blocks

and products

Figure 4.1· Schematic Outline of Technoeconomic Analysis

63
The 35 candidates subjected to the economic analysis represent a complicated mix of processes,

feedstocks, chemical building blocks, and new applications. Therefore, it was convenient to first

separate the candidates into three categories (Table 4,1):

• Direct Substitution: This category describes compounds, that if produced from

renewables, could directly replace the same compounds currently produced from

petrochemicals (for example, butadiene).

• Improved Production: This category describes potential building blocks that are

currently produced from renewables, but not normally considered as feedstocks since

building blocks currently Produced from petrochemicals are more economical. These

. renewable building blocks could substitute for certain petrochemicals if their production

methods could be improved (for example, glucose).

• New Building Blocks/Products: This category describes new chemicals and efficient

processes based on renewables, that could replace a variety of petrochemicals in

selected applications, but whose SPecific end uses have not been defined ( for example,

levoglucosan).

4.2.1 Saeening Based on Comparative Raw Materials Cost Contribution

Throughout this and subsequent sections, a number of comparative evaluations between biOJ7UlSS and

petrochemical-based processes are made. The terms "rllw materials cost" and "raw materials cost

contribution" appearing in these comparative assessments are used to refer to the raw materials cost

contribution to the total manufacturing cost, that includes appropriate adjustments to the market price

for: 1) the starting material, 2) the process stoichiometry, and 3) the yields of the various process steps.

When definitive infonnation is not available, reasonable projections based on using the chemical and

patent literature, as well as RD&D experience were made.

After separating the 35 candidate chemicals and processes into three categories, each is subjected to a

three step screening procedure, based on the raw materials cost contribution:

• A raw materials cost assessment of the biomass route is performed.

• A raw materials cost assessment of the corresponding route from petrochemicals is

Performed, if a comparable route exists. If a petrochemical route is unknown, the

comparison is made with the known existing route to the material.

• The cost of the biomass route is adjusted "upward" by 30% and is compared in the fonn

of a ratio to the petrochemical route.

An important component of this evaluation is the incorporating the "30% rule." A process based on

biomass is considered a promising opportunity for further RD&D when the difference in raw material

costs for a biomass-based process is around 30% less than costs for a current petrochemical-based process.

Incorporating the "30% rule" is shown in the calculations by including a riskfactor of 13, to account for

possible problems, unknowns, intangibles, etc., in a given biomass-based process. This factor is also an

approximation of the minimum cost reduction incentive needed to induce an operator of an existing

technology to invest in the new technology and phaseout the old.

The result of these simple steps provides a set of numbers for comparison in the form of the ratio:

Raw Materials Cost Contribution for Petrochemical (or other) Process

Raw Materials Cost Contribution for Biomass Process x 1.3 (risk factor)

64
CQnplUnd

Direct Substitution

Table 4.1- Summary of Compounds Selected for Saeening

Process or 5tamn& Material for Production from Biomass

Butadiene

Pentanes/Pentene

Benzene/Toluene/Xylene

Acetic/Fonnic/Propionic Acids

Hydroxyacetaldehyde

Phenolics

Resorcinol

Vinyl Phenol

Phenolics

Phenolics

Acetic Acid

Peracetic Acid

Anthraquinone

Acrylic Acid

Improved Production

Glucose

Glucose and Xylose

5-Hydroxymethyl Furfural

Levulinic/Fonnic Acids

Succinic Acid

Gluconic Acid

Sorbitol

Mannitol

Xylose

Xylitol

Furfural

Furfuryl Alcohol

Furan/Tetrahydrofuran

Polyhydroxybutyrate/Valerate

New Building Blocks/Products

Levoglucosan

Cellulose/Hemicellulose/Lignin

Cellulose/Anthraquinone

Cellulose/Anthraquinone

Starch Plastics

Acetylated Wood

Fast pyrolysis/catalytic upgrading

Fast pyrolysis/catalYtic upgrading

Fast pyrolysts/catalytic upgrading

Fast pyrolysis

Fast pyrolysis

Fast pyrolysis

Fast pyrolysis to levoglucosan and chemical processing to

resorcinol

Fast pyrolysis

Wood phenolation (liquefaction)

Lignin hydrotreatment

Syngas

From black liquor acids or starch derived lactic acid

From black liquor or organosolv low molecular weight lignins

Thermal dehydration of starch derived lactic acid or

esterification and dehydration of starch derived lactic acid

From bagasse, corn wet milling, or steam explosion of

lignocellulosics

NREL clean fractionation

Glucose

Qumse

Glucose

Qumse

Glucose

Qucose

Xylose from bagasse or wood

Xylose

Xylose

Xylose

Xylose

SYngasand glucose

Fast pyrolysis

Oean fractionation

Kraft process

Organosolv pulping

Reactive extrusion

Esterification

65
A ratio considerably less than unity indicates that a biomass route could have difficulty competing

with the current petrochemical route. Conversely, a ratio greater than unity indicates a process that

has potential for replacing a given existing route to the material under consideration.

Implicit in this procedure is the definition or consideration of six key components:

• the starting materials that can be used

• the catalysts that can promote product synthesis

• the process type (chemical/thennal or biotechnological)

• the potential volume of the product

• the market price or value of the products

• the costs of the starting materials

4.2.2 Preliminary Detailed Process Evaluation

One outcome of evaluating the 35 candidates based on a simple raw materials cost comparison is

identifying processes that show particular economic promise. Some of these processes have been carried

on to a second, more detailed level of screening to incorporate the costs of processing to predict an

amortized production cost. However, selecting a candidate chemical or process for this more detailed

evaluation depends on more than a promising ratio from the raw materials cost comparison. Also

needed are laboratory results that help dearly define the process parameters necessary for an in-depth

analysis. The key data gathered for this level of technoeconomic evaluation are rates, yields, and

product concentrations, based on existing technologies for selected product or process options that meet or

surpass the "30% rule." Overall process-flow diagrams are then devised for each product, and

approximate equipment sizes are determined from the performance and physical property data.

Capital and operating costs are estimated, and a product amortized production cost is calculated. The

equipment sizes, capital costs, and operating expenses are approximate and are derived by a rule-ofthumb approach to accommodate the largest number of possible options.

Six processes and products were chosen, based on a combination of favorable raw materials cost

contributions, and reliable process performance data obtained from laboratory research (Table 4.2).

These processes have been analyzed in more depth through flowsheets of mass and energy balances, and

amortized production costs have been calculated. Details of these assessments are found in section 5.4.

Table 4.2 - Detailed Process Evaluations Performed

Compound

Direct Substitution

Anthraquinone

Phenolics

Improved Production

Clean fractionation

New Building Blocks/Processes

Acetylated wood

Starch plastics

66

Processes Evaluated

NREL/IPST Kraft lignin

Organosolv lignin

Five conventional processes

NREL Fast Pyrolysis/Fractionation

University of Kyoto (wood phenolation)

NREL process

USDA/FPL

Michigan Biotechnology Institute
:,

4.3 Summary of Tecbnoeconomic Evaluation

Section 5.0 describes the results of the simple comparative evaluation of raw material costs for biomass

versus petrochemical processes. For each chemical evaluated in this section, a block diagram for both

the biomass and petrochemical routes is included to give a rapid description of the technology

employed. The results were prepared using the methodology described in section 4.2, and then subjected

to the "30% rule." Those chemicals identified as most promising have been, or will be, carried on into

the more detailed process evaluation. Several of these more detailed evaluations are given in section

5.4. Where appropriate, projections of conditions necessary to make a presently unfavorable process

economically viable have been made.

Caution must be used when evaluating these results. Evaluation is only as good as the process

information currently available, and when exact information cannot be obtained, then reasonable

estimates must be made regarding potential process performance. As a result, a process that shows an

excellent raw materials cost comparison (for example, hydroxyacetaldehyde, section 5.1.5) may not be

immediately identified as a candidate for further process evaluation because the process is only poorly

defined. Conversely, some comparisons (for example, phenolics from pyrolysis, section 5.1.6) show a

smaller difference between the biomass- and petrochemical-based routes. However, this process has

undergone considerable, more detailed evaluation because the process is much more clearly defined and

projections can be made based on aetuallaboratory RD&D results.

4.4 Current and Projected Markets for Selected Chemicals from Biomass

This section will summarize the market target potentially available to chemicals prepared from

biomass by thermal or chemical processes, and will identify specific market areas where the chemicals

will find a use. Where possible, projections of the market potential in future years are presented.

Complete information in every category is difficult to obtain. Market sizes are given for the U. S. and

the world where available. Information for this section was collected from several sources, listed in

the references. A summary of pertinent market infonnation gathered for these compounds is presented

in Table 4.3.

DIRECI' SUBSTITUTION

4.4.1 Butadiene

Elastomers

The largest use of butadiene is for producing elastomers used primarily by the automotive industry, and

account for 60% of the domestic butadiene consumption. The polymers used in these applications include

styrene/butadiene elastomers, polybutadiene, neoprene, and nitrile rubber. Other polymer

applications of butadiene include acrylordtnle/butadiene/etyrene (ABS) resins, adiponitrile, used as a

precursor to hexamethylenediamine for nylon 6,6 production, styrene/butadiene latexes, polybutadiene,

and styrene-based block copolymers, each accounting for 5%-15% of the butadiene consumption.

The greatest proportion of styrene/butadiene elastomer consumption (70%) and the largest single

market for butadiene is in the tire and tire products industry. This industry also accounts for 78% of

polybutadiene consumption. About 20% of polybutadiene is used in combination with polystyrenes for

the consumer products industry. Another 2% of polybutadiene consumption is in manufacturing

industrial products, such as conveyor belts, hoses, seals, and gaskets.

Neoprene production consumes 5% of butadiene production. Neoprene finds its greatest use in nontire

applications where a polymer with good resistance to weathering and oxidation is necessary. SPecific

uses include in manufacturing hoses, belts, and adhesives.

67
Direct Substitution

•• • W 2\....

Table 4.3• Market Information for Selected Chemicals

(all units in thousand metric tons, unless otherwise indicated)

Chemical Price (S/Ib) U. S. Capacity U. S. Production U.S.Consumption World Capacity World Production World Consumption

Butadiene 0.19 1,737 (1989) 1,400 (1989) 1,713 (1989) 8,080 (1989) 6,400 (1989) 3,967 (1989)

1,894 (1994

estimate)

Pentanes, Pentenes 116(n-pentane; 1988)

13l(mixed pentenes

1988)

BTX (mixture) 0.103 16,958 (1989) 19,743 x 106 32,923 (1989);

gallons (1988) world=N.

20,692 x 106 America, W.

gallons (1993 Europe,Japan

forecast)

a. Benzene 0.15 8,067 (1988) 5,681 (1987) 6,102 (1987) 25.1 x 106 tons 19 .9 x 106 tons

(1989) (1987; forecast of

26.4 x 106 tons 3%-3.5% growth

(1993 forecast) through 1993)

b. Toluene 0.11 5,116 (1992) 3,082 (1991) 3,600 (1991) 15,796 (1992) 7,399 (1991; 7,257(1991; world =

5,116 (1997 forecast) 17,092 (1997 world=N. N. America, W.

forecast) America, W. Europe, Japan)

Europe, Iapan)

c. Xvlenes (mixed) 0.11 5650 (1988) 2694 (1988) 16 598 (1988)

Acetic Acid 0.33 1,647 (1990) 1,618 (1990) 1,547 (1990) 5,593 (1990) 4,668 (1990) 4,617 (1990)

1,737 (1995 forecast) 1,687 (1995 1,610 (1995 6,123 (1995 5,487 (1995 5,3641995

forecast) forecast) forecast) forecast) forecast)

Formic Acid 0.407 16 - 18 (1992) 11 - 12 (1991) 24-25 (1991) 260 (1987)

Propionic Acid 0.41 - 44 102 (1989) 55 (1988) 45 (1988)

Phenol 0.285 1,578 (1988) 1,520 (1987) 1,480 (1990) 4,339 (1988) 4,214 (1987) 4,637 (1990)

1 711 (1993) 5052(1987)
'.',

a. Phenolic Resins 748 (1989) 721 (1989) 1,467 (1989) 1,402 (1989)

783 (1994 1,530 (1994

forecast) forecast)

Resorcinol 6.74 20.4 (1990) 14.5 (1990) 10.3(1990) 41 (1990; world = 30 (1990; world = 24.1 (1990; world = U.S., W. Europe, U. 5., W. Europe, U.S., W. Europe,

Japan) Japan) 'apan)

Acrylic Acid and

Esters 0.69 731 (1991) 1,110 (1988) 957 (1988) 3,212 (1988) 2,127 (1988; world 1,967(1988; world = =U.S., W. Europe, U.S., W. Europe,

Japan) [apan)

Improved Production

Chemical Price ($/lb) U. S. Capacity U. S. Production U.S.Consumption World Capacity World Production World Consumption

Glucose

0.26 (hy) 2,320 (1986) 1,850 (1986) 510 in food 3,510 (1986)

0.51 (anhy) applications

(1986)

Gluconic Acid 0.45 16-19 (1989 estimate) 6.8 (1989 9.1 (l989 estimate) 60 (1985) 36-42 (1985

(and Sodium estimate) estimate)

Gluconate)

Sorbitol 0.77 287 (1990) 178-183 (1990) 180-185(1990) 927 (1990; world 511(1990; world = 495 (1990; world = = u. S.,W.Europe, U. S.,W. Europe, U.S., W. Europe,

lanan. Mexico) Japan) 'apan)

Mannitol 3.32 10 (1980)

Furfural 0.79 72 (1989) 35 (1989) 39 (1989) 240 (1989) 48 (1988; world = 93 (1988; world =

43 (1994 forecast) U. S., W. Europe) U.S., W. Europe,

Japan)

Furfuryl Alcohol 0.80 25 (1989) 20 (1989) 15 for furan resins

(l989)

a. Furan Resins 19.5

69
·

Tetrahydrofuran 1.28 92 (1990) 82 (1990) 63(1990) 141 (1990 world 123 (1990 world = 122 (1990 world = 133 (1995 forecast) 95-99 (1995 75-79 (1995 = U. S., W. Europe, U.S., W. Europe,

forecast) forecast) U. S., W. Europe, Japan) Japan)

Japan) 173-184(1995 163-174 (1995

210(1995forecast; forecast; world := forecast; world := U.

world « U. S., U. S., W. Europe, S., W. Europe,

W. Europe Japan) Japan) Japan)

New Building Blocks/Processes

Chemical Price ($/Ib) U. S.Canacltv U. S. Production U. S.Consumption World Caeacitv World Production World Consumption

Cellulose

derivatives

a. Ravon fibers 240 (1988) 204 (1987) 204 (1988) 2593 (1987)

b. Cellulose 307 (1990) 300 (1990) 169 (1990) 751 (1989) 682 (1989)

acetate fibers 177 (1994

estimate)

c. Cellulose 476 (1992) 345 (1990) 890 (1992) 757(1990)

acetate flake 376 (1995

estimate)

d. Cello"hane 39 (1988) 38 (1987) 40 (1987)

Notes for Table

Compounds listed in italics are subsets of the chemicals immediately preceedlng them and have not been subjected to the economic analysis methodology but

are included because they represent products of industrial utility that could be produced from biomass.

Certain materials are not commercial products and therefore, production information is not available. These materials include: levoglucosan/levoglucosenone,

hydroxyacetaldehyde, vinyl phenol, 5-hydroxymethylfurfural, and levulinic acid.
Nonelastomer Uses

About 15% of the domestic butadiene consumption is used in producing adiponitrile. Almost all of this

material is used to make hexamethylenediamine, a component in the production of nylon 6,6. In 1989,

the United States produced 488 x 1@tons of adiponitrile and 540 x 103 tons of hexamethylenediamine.

Another 11% of butadiene production is used in manufacturing styrene/butadiene latexes for use in the

paper coating and carpet backing markets.

Production of ABSresins consumes smaller amounts of butadiene, primarily for the electronic equipment

industry. Other major applications include appliance components, pipes and plumbing fixtures,

luggage, cases and toys.

Other Uses

Butadiene is a starting material for producing 1,4-butanediol, vinyl cyclohexene (a starting material

for styrene production), olefin oligomers such as 1,5,9 cyclododecatriene for nylon production via nickel

catalyzed oligomerization, and l-octene, used as a copolymer in producing high quality LOPE.

Butadiene also serves as a starting material for producing pelargonic acid, a precursor for heat resistant

lubricants. Pelargonic acid can also be prepared from biomass.

4.4.2 Pentanes, Pentenes

Pentanes and pentenes are obtained from distillation and dehydrogenation processes from petroleum or

natural gas liquids. n-Pentane and i-pentane are obtained as a separable mixture and are used in

solvent applications, as blending components in high octane gasolines, and in producing isoprene.

Pentenes are used in many of the markets for alpha-olefins in general, including the plasticizer and

detergent markets, and as precursors for brominated alkanes that are converted into thiols, amines, Noxides, and ammonium salts. Pentenes have also been used as monomers in producing petroleum resins,

and low molecular weight thermoplastic materials. Copolymers of pentenes with styrene,

divinylbenzene, or vinyl toluene have also been produced.

4.4.3Benzene

Ethylbenzene

The largest single use for benzene in the United States is for producing ethylbenzene, the intermediate

for producing styrene. In 1988,ethylbenzene accounted for 54% of the total benzene demand. In 1990,the

United States produced 4,076 x 1@ tons of ethylbenzene, a production level that is expected to rise to

5,280 x 103 tons in 1993. Styrene is widely used in polymer applications for producing polystyrene,

acrylonitrile/butadiene/styrene (ABS) and styrene/acrylonitrile resins, and styrene/butadiene

latexes.

Cmnene

Another 23% of domestic benzene production (1988) is consumed in reaction with propylene to give

cumene, the starting material for phenol. The United States produced 1,698 x 103 tons of cumenein 1986,

98% of which was used in the phenol/acetone process. Phenol is consumed primarily in producing

phenolic resins, bisphenol A (a key monomer in the production of polycarbonate resins and other high

value engineered products), and caprolactam, the precursor to nylon 6. Further information about

phenol markets will be given below.

71
Cyclohexane

Catalytic hydrogenation of benzene to make cyclohexane accounted for 14% of the domestic benzene

demand in 1988, primarily for producing adipic acid or caprolactam (nylon precursors). In 1988, the

United States produced 1,273 x 10:'tons of cyclohexane.

Nitrobenzene/Aniline

An additional 5% of the domestic benzene demand is for producing nitrobenzene and aniline. The

primary use of aniline is in producing diphenylmethane-4,4'-diisocyanate (MDI), a monomer for

producing polyurethane foams. Polyurethane foams are useful asinsulators and as a component in the

reaction injection molding system used for manufacturing flexible bumpers for the automobile industry.

Aniline is alsoused in preparing accelerators and antioxidants for the rubber processing industry, and as

a key starting material for a number of large volume herbicides, notably Monsanto's Lasso@).

Nitrobenzene is used in producing para-aminophenol, a key component of acetaminophen 0. e.,

Tylenol@). About 9-11 x 1ff tons of nitrobenzene are used for this purpose.

Other Uses

About 110 x 103 tons of benzene, 2% of the total domestic demand, is used for producing linear and

branched alkylbenzene sulfonates for use in laundry detergents, and as surfactants. Benzene is also used

in producing chlorobenzenes (as solvents, insecticide precursors, polymer manufacture), biphenyl (dye

industry), hydroquinone (photographic developer, antioxidant, polymerization inhibitor), and

resorcinol (adhesives, pharmaceutical precursor).

4.4.4 Toluene

The large majority of toluene (>90%) is consumed as a component of gasoline. The remainder of the

toluene produced is used in chemical products and solvents.

Benzene

The largest nonfue1 use of toluene is in producing benzene by hydrodealkylation procedures. This

process consumes 60-70% of the toluene produced for nonfuel purposes.

Other Uses

Toluene is an important component of many solvent systems, especially to produce coatings, paints, and

lacquers for wood furniture, containers, and automotive finishes. However, new methods of coating are

causing a shift away from toluene-based solvent systems, driven by industry's desire to minimize

emissions of volatile organic materials.

About 8% of the total toluene demand is for producing toluene diisocyanate (TOI), a monomer for

flexible and rigid polyurethane foams.

Toluene is also used for producing benzoic acid, an intermediate in certain processes for phenol

production. Obviously, this process contributes only a small amount of phenol to the nation's supply,

because more than 96% of domestic phenol is produced from cumene. Benzoic acid also serves as a

plasticizer, a starting material for other chemical intermediates, and a food additive. Toluene is also

a starting material in preparing benzyl chloride (plasticizer and quaternary ammonium salt precursor),

vinyl toluene (occasional replacement for styrene in certain applications), p-cresol (used primarily in

preparing BHT, an antioxidant>, toluene sulfonic acid (a dye intermediate), benzaldehyde (flavor and

fragrance), and other chemicals.

72
1

4.4.5 Xylenes

Xylene Isomers

Mixed xylenes find their principal use as a source of the individual ortho-, meta-, and para- isomers. 0-

Xylene is a starting material for preparing phthalic anhydride, a widely used plasticizer component.

m-Xylene is used for producing isophthalic add}a component of polyester resins. The para-isomer is

used for manufacturing dimethyl terephthalate and terephthalic acid, important intermediates for

producing polyterephthalates.

Mixed xylenes are also used as solvents, primarily in the paints and coatings industry. Other solvent

uses include agricultural sprays, and in adhesives and rubber in the automotive industry.

4.4.6 Acetic Add

Vinyl Acetate

Vinyl acetate monomer is the largest and fastest growing outlet for acetic acid in the United States, and

accounted for 55% of the total acetic add consumption in 1990. The United States produced 1,161 xl03

tons of vinyl acetate monomer in 1988, most of which was used in polyvinyl acetate emulsions and

resins, and for producing polyvinyl alcohol. Polyvinyl acetates are used mostly in packaging and

labelling as white glue and in construction applications for laminating wallboard and as a smoothing

compound for taped joints. Polyvinyl acetates are also used in latex paints and for finishing wood

composition board. Polyvinyl alcohol is used mostly in textile warp sizing, adhesives and paper sizing.

Other vinyl acetate derivatives include polyvinyl butyral (laminated automobile safety glass,

architectural uses), ethylene/vinyl acetate copolymers (film production, wire and cable, hot melt

adhesives), and ethylene vinyl alcohol (packaging film, microwave food containers).

Acetic Anhydride

An additional 16% of the domestic consumption of acetic acid was used in producing acetic anhydride

(1990). The United States produced 928 x liJ3 tons of acetic anhydride in 1989, and more than 80% of it

was used in producing cellulose acetate, the precursor for cigarette filter tow. Other major markets for

cellulose acetate include textile fibers, plastics, and photographic films. Domestic cellulose acetate

production was 421 x 103 tons in 1990. Acetic anhydride is also used. in smaller markets, for producing

aspirin and acetaminophen (Tylenol~),semiconductor processing and manufacturing herbicides and food

additives.

Acetic Acid Esters

About 11% of the domestic acetic acid demand is used in producing various esters, including butyl

acetate, propyl acetate, ethyl acetate, glycol ether acetates, and amyl acetates. These materials are

used mostly as solvents for inks, paints, and coatings.

Terephthalic Acid /Dimethyl Terephthalate

Producing these materials accounts for 11% of the domestic acetic acid consumption. They are used

mostly in producing polyester fibers, film, resins, coatings and plastics.

Other Uses

Acetic acid is also used for preparing chloroacetic acid, an important chemical intermediate in

producing carboxymethylcellulose, herbicides, surfaetants, and various esters. Acetic acid is also used

in the textile industry in wool dyeing, silk cleaning, printing and finishing.

73
4.4.7Formic Acid

A variety of markets exist for formic acid. About 13-15% of the consumption is in the rubber chemicals

industry where formic acid is used in producing antiozonants and other rubber chemicals, and for

coagulating rubber latex. Manufacturing catalysts based on aluminum and nickel consumes another 10-

15%of the formic acid production. The leather and tanning industry consumes an additional 10-15%in

operations related to hide preparation, although this market has decreased significantly in recent

years. Formic acid is also used in textile dyeing and finishing operations to set and retain colors in

fibers, and as an epoxidation agent in producing plasticizers. '

4.4.8Propionic Acid

As with formic acid, a wide range of markets also exists for propionic acid. About 30% of the domestic

consumption (1988) of propionic acid was for preserving grain and animal feed. Converting propionic

acid to the corresponding sodium and calcium salts accounts for an additional 25% of the domestic

consumption. These materials are useful as food and animal feed preservatives. Producing carboxylic

acid herbicides consumed about 15% of the domestic propionic acid. Propionic acid is also used in

cellulose plastics, pharmaceuticals, and as a solvent.

4.4.9 Phenol

Phenol Resins

Producing phenolic resins takes the greatest share of the phenol market (36% in 1992). The industry

contains many producers because the technology is simple, the capital investment relatively low, and

the range of end products large. About 85-90% of the phenolic resin production is directed toward

bonding and adhesive applications in plywood, insulation, wood, and laminates. The remainder are

used in molding compounds for producing heat-resistant components for appliances, and the electrical

and automotive industries, in protective coatings, and other miscellaneous applications.

Bisphenol A

An additional 36% of the domestic phenol production is directed to preparing bisphenol A, a key

monomer in producing polycarbonate resins, materials of importance in automotive, appliance, and

electronic applications. Other applications for polycarbonate resins are found in producing water and

milk bottles. A additional major use for bisphenol A is in producing epoxy resins, a component of surface

coatings and fiber reinforced laminates for printed circuit boards. Epoxy resins are also expected to

show growth in the aerospace and automotive industries, especially for producing advanced . composites. .

Caprolactam

Producing caprolactam, an intermediate for producing nylon 6, accounts for about 17% of the phenol

consumed domestically. Most of the nylon 6 produced is consumed by the carpet industry. The remaining

caprolactam production is dominated by resin and film production, used in engineering thermoplastics

for the automotive, machinery, film, and wire industries.

Aniline

About 6% of the domestic phenol consumption is directed to producing aniline. Uses and markets for

aniline are described in the section on benzene.

74
Other Uses

Phenol is also a starting material for producing 2,6-xylenol, a precursor to polyphenylene oxides that

form high impact and heat resistant polymers when alloyed with polystyrene. 2,6-Xylenol is also

converted to polyphenylene ethers to give polymers with similar properties, again by alloying with

polystyrene. These copolymers find uses in the automotive market, as well as metal replacements in

the cabinetry and electrical industries. The byproduct of this polymer manufacture is o-cresol, that is

used in resin production, and as a polymerization inhibitor and antioxidant.

Phenol can be alkylated to give long chain alkylphenols, specifically nonyl- and dodecylphenol,

materials that are used in manufacturing nonionic surfactants and detergent grade lubricating oil

additives. Other alkylphenols are used in producing phenolic resins and other polymer additives.

Adipic acid, a key component in the production of nylon 6,6, can be produced from phenol. Adipic acid

results as a byproduct from the production of caprolactam from phenol.

Phenol is the primary raw material used for production of salicylic acid, the precursor to aspirin.

Salicylic acid is also a precursor for wintergreen oil, a flavor and fragrance ingredient, as well as a

pharmaceutical intermediate.

4.4.10Resorcinol

Rubber Products Awlications

Most domestic resorcinol production (70%) is consumed in the rubber products industry as a

resorcinol/formaldehyde resin in a dip treatment for tire carcasses and tread rubber.

Resorcinol/fonnaldehyde adhesives are also used in other fiber reinforced rubber goods, such as belting,

rubberized hose, and rubberized textile sheets.

Wood Adhesive Resins

Resorcinol is used in specialty thermoset resins, either as a straight mix with formaldehyde, or in a

phenol modified resorcinol/formaldehyde mixture. The resins cure at much lower temperatures than

typical phenol/formaldehyde resins to give a strong waterproof and fungus resistant adhesive. These

features give resorcinol/formaldehyde compositions an advantage in structural applications. For

example, about 98% of all structural laminated beams are made using a straight resorcinol-based

adhesive. Phenol modified resorcinol/formaldehyde resins show intermediate properties. The

advantages of a resorcinol-based adhesive must be weighed against the higher cost of resorcinol in any

application.

Other Uses

Resorcinol also serves as an intennediate in producing ultraviolet absorbers in various polyolefin and

cellulose acetate. plastic materials. Resorcinol derivatives are also used in consumer sunscreen

formulations, a market certain to grow in the future. Resorcinol is a precursor for a number of dye

products and pharmaceuticals, including a series of antiasthmatic agents.

4.4.11 Furfural

Furfuryl Alcohol/Furan Resins

Preparing furfuryl alcohol represents the largest domestic use of furfural. Furfuryl alcohol is used

almost completely for producing the so-called "furan resins," a somewhat misleading term since the

monomer used in their preparation is furfuryl alcohol and not furan. Furan resins are important as

7S
foundry binders for producing cores and molds used in casting metals. The chemical, thermal, and

mechanical properties of these resins contribute to their use for this purPOse. Smaller markets also

exist for furan resins, including producing corrosion resistant and chemically inert grouts, mortars and

molded articles, such as pipe fittings, joints, and valves.

Tetrahydrofuran

A small amount of furfural is used for Producing tetrahydrofuran, a material used as a solvent for resins

and plastics and as a reaction solvent in producing pharmaceuticals. The United States produced 73 x

103 tons of tetrahydrofuran (1989), with the largest fraction (71 %) used for producing

polytetramethylene ether glycol, a component of cast and thermoplastic urethane elastomers (for solid

tires and industrial rolls), spandex fibers, and copolyester/ether elastomers (automotive components

and hoses).

4.4.12 Glucose

Food Additives

Glucose finds its largest use in the food industry in baking, beverages, canning, confectionery and dairy

applications. In 1986, these food industries consumed 510 x 103 tons of crystalline glucose, 6,410 x 103 tons

of glucose-fructose syrups, and 2,313 x 103 tons of other glucose containing syrups. One of the largest

areas of growth for glucose consumption is in producing glucose-fructose syrups such as sweeteners.

Glucose can be enzymatically isomerized to fructose and the combination of the two carbohydrates gives

a syrup that is as sweet as natural sucrose. Glucose is also used as a starting material for producing food

grade citric, lactic, and acetic acids, enzymes, amino acids, vitamin C, and certain antibiotics.

Other Uses

The largest nonfood use of glucose is in producing food grade ethanol. The United States reportedly had

an ethanol production capacity of 3.9 x 109 liters in 1988. Glucose is also the starting material for the

dehydrative production of 5-hydroxymethylfurfural, and the coproducts levulinic and formic acid. 5-

Hydroxymethylfurfural is useful as a component of both phenolic and urea/formaldehyde-based

plastics. Glucose can be converted in the presence of hydrogen chloride and methanol into an insulating

foam, and with hydrogen into sorbitol. Glucose is also used for producing adhesives, wallboard and

leather tanning.

4.4.13 Gluconic Add

Chelating A&ents

Most gluconic acid used domestically is handled as the sodium salt, sodium gluconate. An important use

of gluconic acid and its sodium salt, (sodium gluconate) is in alkaline systems for chelation and removal

of metal ions, particularly calcium, magnesium, iron, and aluminum. About 70% of the total sodium

gluconate/gluconic acid consumption in the United States is for metal cleaning and finishing

applications. Other uses include bottle washing, equipment cleaning, in the dairy, beer, and food

service industries, metal etching, degreasing, and electroplating, rust inhibition, and catalyst cleaning.

Other Uses

Gluconic acid/sodium gluconate is also used in producing sodium aluminate, in textile processing, and in

the food industry as a suppressor of the saccharin taste in low calorie foods. Additional markets in the

health food and pharmaceutical industries exist for salts other than sodium gluconate.

76
0 "0" . "/

""

0,

4.4.14 Sorbitol

Personal Care Products

The largest outlet for sorbitol in the United States is in producing toothpaste, cosmetics, and toiletries,

accounting for 32% of the total domestic sorbitol consumption. A large proportion of this use is in the

toothpaste industry where sorbitol can be used as a humidity control agent, a plasticizer, and a viscous

delivery vehicle. This market is influenced by competition with glycerol, which can be used for many

of the same purposes. However, in recent years sorbitol has been used more widely at the expense of

glycerol. Sorbitol is also used in producing mouthwashes, imparting a pleasant, cooling, sweet taste to

these products. The cosmetic industry also uses sorbitol as a humidity control agent and as a gel base.

Because it is hygroscopic, it also serves as an emollient in creams and lotions.

Food Alllllications

An additional 30% of the total market for sorbitol is in food an confections. Sorbitol has been granted a

"generally recognized as safe" designation by the Food and Drug Administration, a confirmation of its

well known nontoxic nature. Sorbitol is classified as a seminatural, nutritive sweetener with 60% of the

sweetness of sucrose. Since sorbitol is resistant to tooth decay bacteria, it is widely used in many

sugarless products, such as sugarless mints and gums, soft candies, chewing gums, and fruit flavored

lozenges.

Sorbitol is also used in food as a bulking agent, peeling aid, and flavoring agent. A recent application of

sorbitol is as a cryoprotectant (to maintain the structural integrity of frozen food), for example, to

produce seafood analogs (e. g., imitation crab).

Vitamin C

About 17% of sorbitol production is directed. toward manufacturing vitamin C. Most vitamin C produced

is used. in nubitional supplements and multivitamin preparations, with lesser amounts being used in

food, beverages, and animal feed.

Surfactants

Producing surfactants accounts for about 10%of the domestic consumption of sorbitol. The surfaetants are

prepared by esterification of sorbitol to provide a wide range of different materials. The major use of

these materials is as lubricant additives, softeners in textile manufacture, plasticizers, antifog agents,

antistatic agents, and components in dry cleaning detergents. Sorbitol-based surfactants are also used in

foodstuff, cosmetic, and pharmaceutical manufacture.

Other Uses

Sorbitol finds additional uses in the pharmaceutical industry as a stabilizer, or sweetening agent for a

number of preparations including cough syrups, and multivitamins. Isosorbide, an antianginal drug, is

prepared directly from sorbitol. Various polyethers can be made from sorbitol, and are used as polyol

components of polyurethane resins and foams.

4.4.15Mannitol

Mannitol is a coproduct of producing sorbitol from the catalytic hydrogenation of sucrose. About 10 x 103

tons of mannitol were produced in 1980. It has a smaller volume than either glucose or sorbitol, but is

used in many of the same areas. Mannitol is the second most important reduction product of sugar and is

used to produce dry electrolytic capacitors, SYnthetic resins, pharmaceuticals, lubricants and

71
stabilizers. It is also used as a nutritive sweetener and is the starting material for synthesis of the

vasodilator mannitol hexanitrate.

4.4.16 Xylitol

Xylitol is produced by the catalytic reduction of xylose. It has a smaller market than mannitol, but is

used as a sweetener, and as a humidity control agent.

4.4.17 Acrylic Acid

Aetylate Esters

The largest use (72%) for acrylic acid is in producing acrylic esters, precursors in a wide range of

polymeric applications, including latexes, textiles, adhesives, paper, leather, polishes, sealants, and

printing inks. A number of new markets are developing for Specialty esters, especially as cross linking

agents for producing hard, cured surfaces. Specific examples of these materials include hydroxyalkyl

acrylates, used for automotive coatings. Multifunctional acrylates are used as part of radiation curable

coatings on film and rigid plastics.

Polyagylic Acid and Salts

Applications of nonester polymers of acrylic acid, available in a wide range of molecular weights,

have shown considerable growth recently. Traditionally, these materials are used as flocculants,

dispersants, sequesterants and thickeners. More recently, new types of polyacrylic acids have been

developed as superabsorbants, that can absorb up to 100 times their weight in water, making them

superior fill for disposable diapers. Another potential growth area for polyacrylic acids is in detergent

applications where the polymers can be used as builders to replace phosphates.

4.4.18 Cellulose Derivatives

A number of derivatives of cellulose, available from pulping wood, have large domestic markets. This

section describes a few of the materials produced from cellulose.

4.4.18.1Rayon Fibers

Rayon fibers are a diverse group of materials, but all are derived from regenerated cellulose. Several

different types of rayon fibers are recognized, depending on their properties. Regular rayon fibers have

a relatively low degree of polymerization, and a cellulose purity of 90-95%. Fabrics made with this

material are smooth, but show poor dimensional stability when wet and dry very slowly. High wet

modulus fibers are made up of higher (95%) purity a-cellulose, and thus have a greater degree of

polymerization. This property results in a fabric with more desirable laundering properties and a much

shorter drying time. Further increase in the degree of polymerization affords the modified high

tenacity rayons, characterized by even greater structural stability as well as high tensile strength.

Polynosic rayons are made in Europe and Japan, and exhibit a degree of polymerization similar to the

high wet modulus rayons.

Apparel

About 51 x 103 tons of rayon fibers were consumed in the domestic production of apparel in 1987. Almost

all rayon used in apparel is in the top-weight category, i. e., fabrics used for production of pants,

sportswear, and other items requiring a heavier fabric. The fabrics are cotton-like, but exhibit greater

uniformity and smoothness. About 96%of the rayon used in apparel was consumed for woven materials,

and the remainder was consumed by knits.

78
Home Furnishings

Domestic consumption of rayons to produce coverings for home furnishings was comparable to that of

apparel. Curtains, draperies, and upholstery account for almost 90% of the rayon use in this category.

Although there was once an oversupply of rayon, in recent years it has become a specialty for use in

higher priced fabrics.

Nonwovens

Producing nonwovens accounted for 32%of the domestic rayon consumption in 1987. The market for these

materials has remained steady since 1983. Rayon nonwovens are used in producing disposable medical

and surgical products, towels, fabric softeners, and interlinings.

Rubberized Goods

A small portion of continuous filament yam fibers is consumed in the production of tire components and

hoses for the automotive industry. This market has lost ground to competing polyester fibers.

4.4.18.2 Cellulose Acetate Fibers

Cigarette Filter Tow

The largest single domestic use for cellulose acetate fibers is for cigarette filter tow, representing 63% of

the domestic consumption in 1989. However, the call for cellulose acetate fibers has fallen considerably

in recent years with the greater recognition of the health hazards associated with smoking, higher

cigarette prices and taxes, and more legislative restrictions on smoking in public places. Currently,

.other markets for this material are opening in Japan and China, as the demand for filtered cigarettes in

these countries increases.

Al'varel

Apparel is the largest textile market for cellulose acetate fibers. The fibers exhibit a softness,

dyeability and breathability that makes them suited for manufacturing lining fabrics such as satins,

taffetas, and twills. Interestingly, as consumers mature, they are expected to demand more of this

material for lined business apparel.

Cellulose acetate fibers are also used for producing curtain and drapery material. However, use of

acetate fibers in home furnishings has generally been declining since 1983. Cellulose acetate fibers also

are used in a number of small volume applications such as wire and cable wrappings, and Paper and

tape reinforcement.

4.4.18.3 Cellulose Acetate Flake and Related Cellulose Esters

Cigarette Filter Tow and Textile Fibers

Cellulose acetate flake serves as the starting point for these materials, as described in section 4.3.18.2.

Cellulose Ester Plastics

Cellulose esters are the nation's oldest thermoplastics and their market share has been declining

gradually. A Considerable portion of the cellulose ester production (34%) is directed to manufacturing

molded and extruded articles, such as tool handles, toys, automotive parts, and other consumer goods.

79
However, similar petrochemical derived materials have taken away from these markets. Cellulose

acetate extruded materials have an advantage in certain niche markets (for example, to produce

steering wheels for luxury automobiles) because of their superior toughness and "feel" upon the hand.

Photo&Taphic Film

About 38% of the cellulose acetate used in plastics production was used in manufacturing photographic

film. The amateur and professional photographic and motion picture industries are still dominated by

cellulose acetate film. However, films derived from polyethylene terephthalate are beginning to

compete in some fields despite a higher cost because of greater dimensional stability and a lower

sensitivity to temperature and humidity variations.

Film and Sheet

The remainder of the cellulose plastic consumption is used for producing films and sheets. Because it can

be cast very thin, cellulose acetate sheeting can be used for print lamination, giving a product with

high optical clarity. This gives the glossy finishes for postcards, book covers, etc. In addition, the

light gauges available make cellulose acetate films ideal for producing pressure sensitive tape, such as

3M's Scotch Brand Magic Transparent Tape. Cellulose acetate is also used for producing ophthalmic

sheet used for eyeglass frames.

4.4.18.4 Cellulosic Surface Coatings

An important group of products derived from different cellulose esters (and ethers, described in section

4.3.18.5) is cellulosic surface coatings. The bulk (over 75%) of the ester derived coatings comes from

nitrocellulose and the rest is produced from cellulose acetate butyrate (CAB) and other esters. These

materials are used in a number of areas.

Wood Furniture

Finishes for household furniture, kitchen cabinets, and other domestic wood materials account for the

greatest consumption of cellulosic coatings. Most of the demand was for nitrocellulose-based material.

These finishes have had little competition in the furniture market because they exhibit a superior

ability to protect wood, have a good gloss, and are easily repaired. An important challenge to this

market results from environmental concerns. The finishes are normally applied as solutions in organic

solvents, and the finished product results from solvent evaporation. New laws restricting solvent

emissions will affect the use of these materials and has spurred the search for low solvent

replacements. To date, the quality of the replacements has been inferior to current formulations.

Cellulose-based lacquers are used in a number of other markets. The automotive industry uses

nitrocellulose-based. lacquers as primer surface coatings. However, this market is also under

environmental pressure to reduce solvent emissions. Nitrocellulose lacquers are used in the paper and

film industry as coatings to reduce moisture permeability, although this market is decreasing because of

competition from wraps based on polyvinylidene chloride 0. e., Saran Wrap). These lacquers can also

be used for coating of paper, book covers, wallpaper, etc. Other smaller coating markets exist in the

machinery, container and fabricated plastics industries.

80
4.4.18.5 Cellulose Ethers

Sodium Carboxymethylcellulose

The most widely used cellulose ether is sodium carboxymethylcellulose (CMC), accounting for 39% of

the domestic consumption of cellulose ethers in 1990. The greatest proportion of this material (17%) is

used in the food industry as a stabilizer, thickener, and moisture retention aid. It is used as an additive

in diet foods because it is not metabolized.

An additional 12% of the CMC produced is used by the oil drilling industry where it is used as a

viscosity enhancing agent in drilling muds used to cool and lubricate drill bits. CMC is used as a partial

replacement for bentonite clays in the mud formulations.

A number of other markets exist for CMC use. CMC is used in the pharmaceutical and cosmetic

industries as a thickener and binder. It serves as a soil antiredeposition agent in detergents, and as a

water retention aid in paper coatings. When it is coated on yam filaments, CMC holds fibers together

during weaving. A possibly emerging market for CMC is as a binder in taconite pellets produced by the

iron ore industry.

Hydroxyethylcellulose

An additional 31% of the cellulose ether consumption is for producing hydroxyethylcellulose (HEC),

and the related carboxymethylhydroxyethylcellulose. Most of the HEC production is used in

manufacturing surface coatings, for example, in water-based latex Paints.

HEC forms protective colloids in the polymerization of vinyl acetate and acrylics. The result is an

improvement in polymer particle size, reaction yield and stability.

Other applications of HEC are found again in oil drilling operations, building products,

pharmaceuticals, and in manufacturing personal care products.

Other cellulose ethers are used in similar markets. Materials manufactured include methylcellulose,

hydroxypropyl cellulose, ethylcellulose, and ethyl hydroxyethyl cellulose.

4.4.18.6 Cellophane

Cellophane's introduction in 1924caused a revolution in the packaging industry, and it quickly became

a key material in the domestic consumer market. However, the market has declined from a high of 200

x lW tons in 1960 to 40 x lcftons in 1987,as a result of increasing competition from petrochemical derived

packaging materials. The market could be affected by environmental concerns in the future, as

cellophane is the only packaging material that is biodegradable.

81
s.o INDIVIDUAL RAW MATERIALS COST COMPARATIVE EVALUATIONS

A summary of the results of this evaluation is found in Table 5.1.

5.1 Direct Substitution

5.1.1 Butadiene

From biomass:

Light hydrocarbons

and gases

Lignocellulose

preparation

Catalytic

• Fast • Oil :nITding ~BUTADIENE pyrolysis vapors

,

separation

. , Char Heavier

materials

From petrochemicals:

Natural Gas § Liquids --.. er=g (ethane/propane)

Ethylene/

Propylene

C-4 Olefin

Coproduets

and Heavier

Materials

Extractive

Distillation

,

Heavier

Materials

~BUTADIENE

:'·1

Processes Compared: The biomass-based route to butadiene begins with the fast pyrolysis of wood.

Butadiene is prepared by dehydrogenation of mixed three- and four-carbon streams resulting from the

interaction of the pyrolysis vapors with a zeolite-type catalyst. Almost all domestic butadiene is

produced commercially by the pyrolysis of ethane or propane, isolated from natural gas liquids. This

thennal cracking produces about 22 million lb/year of butadiene as a coproduct among a variety of other

materials from distillation (for example, pentanes and pentenes, as shown in section 5.1.2).

Raw Materials Cost Comparison: The current production cost of the ethane starting material from

natural gas fractionation is about $O.055/lb, assuming the natural gas feedstock costs $1.66/thousand .

cubic feet. Current RD&D results indicate a potential 16% yield of butadiene from wood feedstock,

giving a raw material cost contribution of $0.091/lb, assuming the wood feedstock is available at

$40/dry ton. The ratio of the petrochemical and biomass raw material costs is then

0.055/0.091 = 0.60

and when a risk factor of 13 is included, the ratio becomes

0.60/13 =0.47

83
Table 5.1-Summary of Raw Materials Cost Contribution Screening Results

Direct Substitution

Existing Proposed Biomass Based

Commercial Process, ($/Ib)/Yield to Comparative Ratio,

Chemical Process (S/Ib) Achieve(%) Existing/Biomass x 1.3 NecessaO' Conditions for Biomass to Compete

1) Butadiene 0.055 0.091/16 0.47 higher efficiency or crude oil at $35/barrel and

wood at S20/ton; new feedstocks, e. g., RDF

2) Pentanes/Pentenes 0.057 0.102/12.4 0.43 higher efficiency or crude 011 at $35/barrel and

wood at $20/ton; new feedstocks, e. g., RDF

3) BTX 0.103 0.082/24 0.97 already promising, but 30% yield would

improve outlook

4) Acetic/Propionic/ 0.03 (as NaCI 0.043/10 0.69 new product applications; higher yield in acids

Formic acids for road deicing) production

5) Hydroxyacetaldehyde 0.086 0.053/10 1.25 80% recovery of HAA from pyrolysis oils

6) Phenolics by pyrolysis 0.135 0.094/21 1.17 already rompetitive; recommended.

7) Resorcinol 0.153 0.156/80 0.75 further study needed to define process

conditions

8) Vinyl Phenol 4.82 0.5/10 7.40 already competitive; further study needed to

define process conditions

9) Phenolics by Wood 0.135 0.106 1.09 already competitive; RD&:D to Improve process

Phenolatlon will improve outlook

10)Phenolics by Lig- 0.135 0.12/10 1.22 already competitive; RD&:D to Improve process

nin Hydrotreating will improve outlook

11) Acetic acid from

Biomass Syn Gas 0.052 0.041 see text nearly competitive; RD&:D to Improve process

will improve outlook
Table 5.1 - continued

12) Peracetic Acid

from kraft black liquor

from starch

13) Anthraquinone

14) Acrylic Acid

Improved Production

0.16

0.16

1.00 - 1.98

0.145

0.15/90 in chemical steps

0.20/90 in chemical steps

0.822 - 1.04

0.076/36

0.82

0.61

0.92 - 2.57

0.30 - 1.47

possibly competitive; RD&D needed to evaluate

process

already competitive

already competitive

Chemical

Existing Commercial

Process (Sllb) Cost by Improved Biomass Route ($/lb) Comparative Ratio. EXisting/Biomass x 1.3

1) Glucose

from bagasse

from corn starch

from steam explosion

2) 5-Hydroxymethylfurfural

3) Levulinic/Formic Acids

4) Succinic Acid

5) Gluconic Acid

6) Sorbitol

7) Mannitol

8) Xylose

from lignocellulose, 3 coproducts

from lignocellulose, 2 coproducts

9) Xylitol

0.08 0.032 (3 coproducts)

0.05 0.032 (3 coproducts)

0.056 0.032 (3 coproducts)

0.102 0.088 (1 coproduct)

0.065 (3 coproducts)

0.164 (levullnlc) 0.105 (3 coproducts)

0.064(formic) 0.041 (3 coproducts)

0.11 0.16

0.058 0.040

0.059 0.056 (2 coproducts)

0.065 0.043 (3 coproducts)

0.09 0.027

0.09 0.034

0.103 0.037

85

1.92

1.20

1.35

0.043 (l coproduct)

1.21

1.20

1.20

0.53

1.12

1.31

1.16

2.56

2.04

2.14
Table 5.1 • continued

10) Furfural 0.10 0.062 1.24

11) Furfuryl alcohol 0.116 0.075(3 coproducts) 1.35

12) Furan/Tetrahydrofuran 0.104 0.095 (3 coproducts)

13) Tetrahydrofuran 0.108 0.117 (3 coproducts) 0.71

14) Polyhydroxybutyrate/

polyhydroxyvalerate 0.58 0.10 4.46
This low ratio indicates that the biomass-based route to butadiene probably cannot compete with the

petrochemical route given current feedstock prices and yields of butadiene. However, manipulating

feedstocks, or changes in raw material costs could present conditions conducive to using biomass derived

butadiene in the future.

Future Projections: If the price of crude oil rises to $35/barrel and the price of the wood feedstock drops

to $25/dry ton, a similar calculation shows that the ratio of raw material costs rises to 0.93, suggesting

that a biomass-based route to butadiene might have a chance to compete. Alternatively,waste

feedstocks rich in polyolefins (such as refuse derived fuel) are attractive for routes to butadiene, since

the yield of hydrocarbon from these materials is substantially greater than from lignocellulose (Rejai,

et al, 1991). The ratio that results from comparing the biomass and petrochemical routes then is

significantly greater than unity, justifying further RD&D to optimize the process.

5.1.2PentanesIPentenes

From biomass:

Lignocellulose

preparation

light hydrocarbons andT

Fast Oil

pyrolysis vapors

Char.

Catalytic

~ing

separation

~er materials

~PENTANES,

PENTENES

From petrochemicals:

Heavy

hydrocarbon

feedstocks

Ethylene/

/"'" Propylene

---·~I=I C-SOIefin

coproducts Extractive

ana heavier distillation

materials

~PENTANES,

PENTENES

materials

Processes Compared: The processes compared are similar to those described for producing butadiene.

Pentanes and pentenes can be produced from biomass by treating vapors derived from the fast pyrolysis

of wood over a zeolite-type catalyst. Heavy hydrocarbons, such as naphtha and gas oil, are partially

converted into five-carbon units as part of the wide range of materials produced by cracking to produce

primarily ethylene and propylene. The most widely used five-carbon olefin in the United States is

isoprene, with a total domestic production of about 300 million lb/year.

Raw Materials Cost Comparison: The current raw material cost for the heavy hydrocarbon feedstock

for pentane/pentene production from petrochemicals is $O.0571Ib, assuming a crude oil price of

$20.00/barrel. A biomass-based route gives about a 12% yield of pentanes/pentenes from wood

87
pyrolysis. The raw material cost for the biomass-based route is $0.102/lb of pentanes/pentenes,

assuming wood feedstock costs $40/dry ton, and a fuel value credit for the other coproducts produced

during pyrolysis. The ratio of the petrochemical and biomass raw materials costs is then

0.057/0.102 = 0.56

and when a risk factor of 1.3 is included, the ratio becomes

0.56/1.3 =0.43

The low value of the ratio shows that a biomass-based route to pentanes/pentenes probably would not

be competitive with the current petrochemical routes, given current feedstock prices and yields of the

biomass processes. As in the case of butadiene, manipulating feedstocks, or changes in raw material

costs could present conditions conducive to using biomass derived pentanes and pentenes in the future.

Future Projections: If the price of crude oil rises to $35/barrel and the price of the wood feedstock drops

to $25/dry ton, the ratio of raw material costs rises to 1.03, suggesting that a biomass-based route to

these materials might have a chance to compete. Alternatively, waste feedstocks rich in polyolefins

(such as refuse derived fuel) are an attractive feedstock for routes to monomeric olefins, because the

yield of hydrocarbon from these materials is substantially greater than from lignocellulose (Rejai, et

al, 1991). The ratio that results from comparing the biomass and petrochemical routes then is

significantly greater than unity, justifying further RD&D to optimize the process.

5.1.3 BenzenelI'oluenelXylene (BTX)

From biomass:

light hydrocarbons

and gases

Catalytic

upgrading

and

separation

lignocellulose

preparation

Fast Oil

pyrolysis vapors

Char

,BENZENE i ...--.. TOLUENE

fraction

" XYLENES

From petrochemicals:

_ BTX.

fraction Naphtha

light material

+ _I ~munlY~icg I-"~I first , nt:IU, separation

,

heavy material

88

,BENZENE

r---.. ~TOLUENE

XYLENES
Processes Compared: BTX can be produced from biomass by the fast pyrolysis of wood, followed by

catalytic conversion of the vapors to gasoline and recovering the BTX from the gasoline product. Two

routes exist for catalytic conversion and upgrading. A low pressure route can be thermally integrated

with the pyrolysis through vapor phase catalytic cracking, or the liquid phase can be hydrotreated at

high pressure (Elliott et al, 1991). BTX is produced in a similar manner commercially, by recovering the

BTX fraction from gasoline derived from catalytic reforming of naphtha feedstocks that are available

from crude oil,

Raw Materials Cost Comparison: The raw material cost contribution to commercially produced BTX is

$O.103/lb, assuming a crude oil costs $20/balTel. The biomass-based process affords a 24% Yield of BTX,

giving a raw material cost contribution of $0.082/lb,assuming wood feedstock costs to be $40/dry ton.

Comparing the two costs gives a ratio

0.103/0.082 = 1.26

and when a risk factor of 1.3 is included, the ratio becomes

1.26/1.3 = 0.97.

The relatively high value of this number, based on actual process results, indicates that a process to

produce BTXfrom biomass could be competitive with the current petrochemical process.

Future Projections: Introducing lower cost feedstocks, such as waste, will further increase the value of

the petrochemical/biomass ratio, indicating that BTX from a biomass route could compete with the

petrochemical processes. This process has been evaluated at a much higher level of detail (Diebold et

al, in press).

5.1.4 AceticJFormicIPropionic Acids

From biomass:

Light hydrocarbons

and gases

•

Others

u

ceWuiose

preparation

From petrochemicals:

Fast

pyrolysis

t

Char

Oil

fractionation

t

Hydroxyaceta1dehyde

ACETIC,

FORMIC,

PR.OPIONIC ACIDS

PIN

oils (phenolics)

Methanol ACETIC

ACID

--I.~ PR.OPIONIC

ACID

Natural

gas or coal

Ethylene

Butanes

Syn

Gas

• Carbonylation

• IOxidationI Mixed

aliphatic

acids

89

• ISeparation I

t

Acetic acid

and others

FORMIC

ACID
Processes Compared: A mixture of acetic, formic, and propionic acids is available from the fractionation

of crude pyrolysis oil derived from wood. About a 10% yield of mixed acids is currently obtained from

the pyrolysis of wood feedstock. For simplicity, the mixture was considered to be pure acetic acid, and

was compared to the commercial acetic acid process from methanol described above. Petrochemicals

are converted into the acids of interest in routes using several feedstocks. Almost 75% of the domestic

acetic acid production starts from natural gas using the Monsanto process, with the remainder being

prepared by alternate routes. Ethylene, from the pyrolysis of ethane derived from natural gas, can be

carbonylated to give propionic acid. Finally, formic acid can be obtained as one component of a mixture

of acids resulting from the partial oxidation of butane.

Raw Materials Cost Comparison: Fast pyrolysis does not produce high yields of the acids, therefore,

the acids need to find a cost effective use as a mixture. For example, converting this acid mixture to a

mixture of acid salts to use as a road deicer was considered. The raw material cost of preparing the acid

salts was compared to the raw material cost of the most widely used road deicer, sodium chloride. The

raw material cost for producing mixed acid salts is $O.043/lb, assuming acetic acid costs $O.065/lb, lime

(required to convert pyrolysis acids into the corresponding salts) costs $O.02/lb, and a quantitative

yield of salts from the simple acid/base reaction. Sodium chloride costs $O.03/lb giving the ratio

0.03/0.043 =0.69.

A risk factor was not included in this analysis since the reaction between acid and lime is operationally

simple and proceeds in almost quantitative yield.

Future Projections: If the yields of the acids produced during pyrolysis can be increased, or new, higher

value applications for the mixed acid salts in solution are developed or lower cost feedstocks are used,

the ratio between biomass and petrochemical derived materials would increase, indicating that mixed

acids from a biomass route could eventually compete as a precursor to road deicing material.

5.1.5 Hydroxyacetaldehyde

From biomass:

Others

PIN

oils <phenolics)

Li ugno- Fast cellulose

preparation pyrolysis

Oil

fractionation - ..... HYDROXYACETALDEHYDE

Acetic

formic,

propionic acids'

Processes Compared: Hydroxyacetaldehyde is a potential coproduct from the fast pyrolysis of wood. It

is present in the mixed acid fractions (evaluated above) in a yield of about 10%. Since it is not currently

a commercial product, there is no petrochemical route for comparison. Instead, the cost of

hydroxyacetaldehyde from biomass is compared to glyoxal, a known cross-linking agent for

manufacturing resins. Hydroxyacetaldehyde is predicted to be a promising replacement for glyoxal for

this use. Glyoxal is produced by the catalytic oxidation of ethylene glycol using oxygen as the oxidant.

Raw Material Cost Comparison: The raw material for producing hydroxyacetaldehyde from biomass in

a coproduct recovery scheme is $0.053/lb, assuming wood feedstock costs of $40/dry ton. Production of

90
glyoxal from petrochemicals requires a raw material contribution of $0.086/lb. Comparing the

petrochemical route to the biomass route gives the ratio

0.086/0.053 =1.62

and when a risk factor of 1.3 is included, the ratio becomes

1.62/1.3 =1.25.

This relatively large ratio suggests that hydroxyacetaldehyde prepared from biomass could favorably

compete with glyoxal from petrochemicals in the crosslinker market, based on Taw materiJll costs only.

However, little is currently known about methodology to separate the hydroxyacetaldehyde from the

crude acid mixture derived from pyrolysis. Losses would certainly occur, and could cause the ratio to

drop.

Future Projections: Further information on separation technology is necessary before a complete

evaluation can be made. .

5.1.6 Phenolics (by pyrolysis routes)

From biomass:

Ught hydrocarbons

and gases

t

Ugnocellulose Fast

preparation pyrolysis

1

From petrochemicals:

Others

Hydroxyacetaldehyde

PIN

OILS (PHENOLICS)

Acetic

formic,

propionic acids

Benzene

Propylene

ISeparation I

,

Acetone

• PHENOL

Processes Compared: Mixed phenolics are available as one of the components derived from a postpyrolysis fractionation of oil. The oil comes from wood in a weight percent yield of 20-25% from a

softwood feedstock, or 18-20% from a hardwood feedstock (Chum and Black 1990; Chum et al, 1989).

Phenol is produced commercially from petrochemicals by the cumene process, starting from benzene and

propylene, which generates acetone as a coproduct.

Raw Materials Cost Comparison: The raw materials cost of phenol produced by the commercial cumene

process is SO.135/lb phenol, assuming benzene costs $O.157/lb, propylene costs $O.13/lb, and assigning

propylene costs to acetone. These costs assume erode oil costs $20/barrel. The raw materials cost of

91
mixed phenolics produced by wood pyrolysis is SO.094/lb, assuming softwood feedstock costs $40/dry

ton. Comparison of the petrochemical and biomass-based processes give the ratio:

0.135/0.094 =1.44

and when a risk factor of 1.3 is included, the ratio becomes

1.44/1.3=1.17.

A comparison of this ratio to that obtained in the hydroxyacetaldehyde case (section 5.1.5) is

interesting. The absolute values of the ratios, after applying the "30% rule", suggests that

hydroxyacetaldehyde (ratio of petrochemical/biomass routes = 1.25) should be considered more

strongly than a biomass route to phenolics, with a ratio of 1.17. However, the results for producing

phenolics is based on an established process, verified by repeated trials in an RD&D environment. No

similar information base is a'Dailable for producing hydroxyacetaldehyde from biomass. The

information used in the hydroxyaceta1dehyde evaluation is from smaller scale runs (Scott, et al, 1982)

and not from isolating hundreds of pounds of material as practiced in the P/N oil production. This

process is an important component of the ongoing NREL program to develop new methods for the

converting biomass into useful chemicals. Using this material in the adhesives industry is the basis of

the current OOE/Orr/NREL Pyrolysis Materials Research Consortium (Chum et al, 1991). In this case,

we envision that waste wood would be the feedstock that would make the already attractive

biomass/petrochemical ratio even higher. The intent is to partially replace phenol in

phenol/formaldehyde thermosetting resins, an application that does not need pure phenol.

Future Projections: A more detailed process and capital cost evaluation of the biomass-to-phenolics

route is certainly warranted, and more RD&D information is necessary on a route to

hydroxyacetaldehyde from biomass.

5.1.7Resorcinol

From biomass:

Phenolics

~~Separation~ ~~:s.m • RESORCINOL

....._-.1

Acidic

prehydrolysis

U

ce~se preparation

Soluble

material Others

From petrochemicals:

Benzene

Propylene

Diisopropyl

benzene ~I Oxidation I Separation I RESORCINOL

Acetone +

92
•

Processes Compared: Resorcinol is potentially available from biomass by a two-step procedure that

first converts cellulose to levoglucosan (section 5.3.1) using fast pyrolysis of acid treated biomass, and

then to resorcinol by an electrochemical process. Resorcinol can be produced from petrochemicals by two

methods starting from benzene. The first route is similar to the cumene route for converting benzene to

phenol. Benzene is treated with excess propylene to give diisopropylbenzene, followed by oxidation to

give resorcinol and acetone as coproducts. Alternatively, benzene is sulfonated with sulfuric acid and

the resulting material is fused with alkali to give resorcinol. The alkali fusion route was not

evaluated because of the high raw material costs.

Raw Material Cost Comparison: The raw material cost contribution to resorcinol for a biomass-based

process is $O.l56/lb, assuming levoglucosan costs $O.068/lb (cost derivation given below in section 5.3.1),

electricity costs $0.05/kwh, and there is a yield of 80% in the conversion. Since the electrochemical

step is supplying electrons, electricity can be evaluated from a cost standpoint as another raw material.

Resorcinol from petrochemicals is produced at a raw materials cost of $O.153/lb, assuming benzene costs

$O.157/lb, neglecting the cost of the materials in subsequent steps, which are assumed to be small, and

assuming a 90% yield in each of the chemical steps.

Comparing the petrochemical route to the biomass route gives a ratio

0.153/0.156=0.98

and when a risk factor of 1.3 is included,the ratio becomes

0.098/1.3 =0.75.

Note that including all the costs of the petrochemical route to resorcinol would only improve the

projection.

Future Projections: The biomass/petrochemical ratio indicates that resorcinol from biomass has a

chance of competing with the current petrochemical route. However, the current process description is

rough and has used reasonable estimates of yields for the converting levoglucosan into resorcinol.

Therefore, further laboratory RD&:D is necessary to obtain the necessary process performance

information for a more detailed evaluation.

5.1.8Vinyl Phenol, an Example of a High Value Phenolic Produced by Biomass Pyrolysis

From petrochemicals:

Phenol

From biomass:

N"me • reaction

steps

Separation!

purification

VINYL - ......·~PHENOL

Biomass Fast

pyrolysis --.l.~JSeparationl VINYLPHENOL

Processes Compared: Vinyl phenol, a specialty monomer and additive in the food and fragrance

industry, is currently produced on a small scale as a fine chemical. The process begins from phenol,

proceeds through nine separate chemical operations, and consumes malonic acid, acetic anhydride,

hydrogen chloride, hydrogen cyanide, caustic, and sulfuric acid. Vinyl phenol is also available as one

of the products obtained upon fast pyrolysis of lignoceUulosics.

93
Raw Material Cost Comparison: Because of the complexity of the petrochemical route, a number of

assumptions were necessary. The raw material cost contribution to vinyl phenol from petrochemicals is

about $4.82/lb, assuming the starting phenol costs $O.40/Ib, and there is an 80% yield in each of the

subsequent chemical steps. Given the number of steps involved, and the heavy use of auxiliary raw

materials, this estimate is considered low. In comparison, the raw material cost contribution to vinyl

. phenol prepared from biomass is projected to be about $O.50/lb, assuming a 10% yield of vinyl phenol

from pyrolysis and only a 10% efficiency in its recovery from the other products present in the mixture.

Comparing these results gives the ratio

4.82/05 =9.64

and when a risk factor of 1.3 is included, the ratio becomes

9.64/1.3 = 7.4.

Future Projections: This high ratio indicates that further investigation into the recovery of vinyl

phenol from biomass is warranted, especially in separating the vinyl phenol from the pyrolysis oil

mixture.

5.1.9Phenolics from Wood Phenolation

From biomass:

Wood

P/Noil

..

Ph Ii ---""II1IL..1 Phenolics l---""""IIIL Light eno CS""'"""li['"" recycle ...........-- materials

+ •

Phenolation

reactor

t

Acid

catalyst

PHENOLATED

WOOD

From petrochemicals:

Phenolics~ Phenolics light

recycle materials

Wood + +

• IDistillatio3 Phenolation .., .. PHENOLATED

Phenol .. reactor WOOD

t

Acid

catalyst

Processes Compared: Phenolated wood can be made from phenol or a phenolics fraction from a pyrolysis

PIN oil. This phenolic fraction has potential use in foams, adhesives, moldings and fibers.

94
Raw Material Cost Comparison: The raw materials cost of producing a phenolated wood is $O.106/1b,

assuming wood feedstock costs $40/ton and P/N oils cost $O.094/1b. Production of a phenolated wood

using petrochemical derived phenol has a raw material cost of SO.150/1b, again assuming wood costs

$40/ton and phenol costs of $O.41/lb. Comparing these results gives the ratio

0.150/0.106 =1.42

And when a risk factor of 1.3 is included, the ratio becomes

1.41/1.3 =1.09.

This ratio indicates that the biomass-based process could potentially compete with a process based on

petrochemical derived phenol.

5.1.10Phenolics (by hydrotreating of lignin)

From biomass:

Cellulose

Lignocellulosics Fractionation

preparation

Hemicellulose

From petrochemicals:

Lignin

Hydrogen

.J- METHYL • PHENOLICS ~ARYL

ETHERS

Methanol

Processes Compared: Hydrotreating of lignin, available from a variety of sources, affords a mixture of

phenolic products. Treating the phenolics with methanol gives a mixture of methyl aryl ethers (MAE).

95
Two comparisons are made: a comparison of the cost of phenolics prepared by hydrotreatment of lignin

to phenol prepared by the commercial cumene route, and a comparison of the cost of MAE to methyl

tert-butyl ether (MTBE). MAE and MTBE are used as oxygenated gasoline additives. MTBE is

prepared commercially from isobutylene and methanol.

Raw Materials Cost Comparison. Phenolics Production: The raw materials cost for producing a phenolic

material by hydrotreating of lignin is SO.OS5/lb, assuming that lignin (from NREL "clean

fractionation") is available for SO.03Ulb, hydrogen is available at SO.54/lb, and the hydrotreating

process gives a 10% yield of phenolics. In comparison, phenol produced via the cumene process has a

raw material cost of $O.135/lb, calculated in section 5.1.6.

Comparing the costs of the petrochemical process to the biomass process gives the ratio

0.135/0.085 =1.59

and when a risk factor of 13 is included, the ratio becomes

1.59/13 =1.22

This ratio indicates that "clean fractionation" of lignocellulose (described in section 5.2.1) will give an

inexpensive feedstock for producing phenolics that has a good opportunity to compete with material

currently produced from petrochemicals.

Raw Materials Cost Comparison. MAE/MTBE Production: The raw materials cost for preparing MTBE

from petrochemicals is SO.06/lb, assuming that methanol is available at S035/gal and ethane (the

precursor to isobutylene from natural gas liquids) is available at $O.25/gaI. The cost of raw materials

for the preparing mixed aryl ethers from lignin is $O.12/lb, assuming that lignin is available at a value

of SO.025/lb, and methanol used in the process costs $035/gal. The hydrocracker is assumed to give a

total product yield of 48% with 23% conversion to mixed aryl ethers. Comparing the conventional

process to the biomass process gives the ratio

0.06/0.12 = 0.5

and.when a risk factor of 13 is included,the ratio becomes

0.5/13=038

The low value of this ratio indicates that producing mixed aryl ethers from hydrotreating will not

compete with MTBE in the gasoline additive market under current feedstock assumptions and the low

yield of MAE obtained from hydrotreating.

Future Projections: As in all of these evaluations, a sensitivity analysis can be performed. If the yield

of the hydrotreating step rose to 72%, with 100% recovery of phenolics, the raw material cost drops to

$0.09/lb, giving a final ratio of 0.51 for producing MAE from phenolics derived by lignin hydrotreating.

This ratio is still quite low, even using a highly optimistic projection of possible hydrotreating

performance.

5.1.11510 Gas

A direct comparison of the cost of syn gas produced from biomass versus petrochemicalsis difficult, since

"syn gas" is a generic term for a mixture of hydrogen and carbon monoxide. Different ratios of the

component gases are possible from petrochemicals depending on the methodology employed. Of greater

interest is comparing costs of products that can be derived from syn gas, for example, acetic acid (section

5.1.12).

%

:r :'
5.1.12Acetic Acid from Syn Gas

From biomass:

=':-ose

preparation ~IGasifierl'" gassyn MethanOI~ICarbonYlatiOn , ,

I ~~C

From petrochemicals:

Natural Syn

gas or coal Gas Methanol ACETIC

ACID

Processes Compared: Both processes use syn gas as thestarting material for acetic acid production. The

key process feature is the higher level of carbon monoxide (CO) in syn gas produced by wood

gasification. Conventional production of syn gas from natural gas gives a H2/CO ratio of 3.0, and

production from wood gives a ratio of 0.8 -1.5. The presence of excess CO from wood gasification gives a

process that uses part of the CO for methanol production (the precursor to acetic acid) and the excess CO

for converting the methanol to acetic acid. Two different biomass gasifiers were evaluated: the IGT

(direct) and the BeL (indirect) processes. Producing acetic acid from petrochemicals relies on a

catalytic carbonylation of methanol, produced using the Monsanto acetic acid process.

Raw Materials Cost Comparison: Comparing the raw material costs of the petrochemical and biomassbased routes gives a ratio of 0.6, assuming natural gas costs $1.66/Mft3. This number is based on actual

perfonnance results from an engineering unit operating on biomass gasification. A biomass-based process

to acetic acid could compete with current petrochemical-based processes under several scenarios shown

below in the sensitivity analysis.

Future Projections: A sensitivity analysis has been performed to show the effect of change in feedstock

costs on the ratio of raw material costs for the processes and the results are shown below.

Cost of Biomass ($ / dO' ton)

Cost of Methane

C/Mtt31

$1.00

$2.00

$3.00

$4.00

S3QJ!Q

0.6

1.2

1.9

2.5

$40.00

0.4

0.9

1.3

1.8

$50.00

0.3

0.7

1.0

1.4

$60.00

0.3

0.6

0.8

1.1

Note that either a drop in wood feedstock costs or an increase in methane costs by 20% can give ratios of

unity, and suggest that acetic add could be produced economically from wood gasification if methane

costs about $200/Mtt3, and wood costs $3O-4O/dry ton.

97
5.1.13Peracetic Acid

From biomass:

~J~:OXY ~IOxidatiOn Acetaldehyde

t

Lignin

Acid

precipitation ~~ExtractionI

-------.. t

Kraft

black

liquor

t ~OxidatiOn I....3IIIoo.....PERACETIC

"""""'AOO

Starch

preparation hydrolysis Acid I I I Fermentation

t

~Ic ......1Qx;dationl ......tyde

~Oxidation I ~~~~CETIC

From petrochemicals: . /

Natural § gas ~:tg Ethylene liquids ~IOxidation I Acetaldehyde

t

PERACETIC ~OxidatiOnI AOO

Processes Compared: Two biomass-based processes have been suggested for producing peracetic acid.

The feedstocks are wastes from starch rich food processing streams or are compounds, such as lignin

derived from pulping black liquor that are normally used for their fuel value. The first begins with

mixed hydroxy acids available from fractionation of kraft black liquor. These acids, which are present

in substantial amounts in black liquor, have a low heat content, limiting their fuel value. However,

they could be used for peracetic acid production in this process by developing cost effective

fractionation routes. The hydroxy adds are converted by oxidation to acetaldehyde, and then to

peracetic acid. The second route converts glucose, derived from starch containing waste streams or com

starch, into lactic acid, followed by the same oxidation sequence to give peracetic acid. Peracetic acid

is produced commercially from petrochemicals by the two-stage liquid phase oxidation of ethylene.

Raw Materials Cost Comparison: The projected raw material cost of peracetic acid from kraft black

liquor is $0.15/Ib, assuming that the mixed hydroxy acids can be efficiently separated from the black

liquor, and that the oxidation steps each proceed in 90% yield. A route from com starch gives a raw

material cost of $0.20/Ib, assuming starch costs $0.07lIb and the same 90% yield performance in the

oxidation steps. Producing peracetic acid from ethylene has a raw material cost of $O.16/Ib, assuming

98
an ethylene cost of $0.20/lb. Comparing the cost of the petrochemical routes to those from biomass gives

the ratios

(from kraft black liquor) 0.16/0.15 =1.07

(from starch) 0.16/0.20 =0.8

and when a risk factor of 13 is included, the ratios become

(from kraft black liquor) 1.07/1.3 =0.82

(from starch) 0.8/13 =0.61.

These ratios indicate that a route to peracetic acid starting from kraft black liquor has a chance to

compete with the current petrochemical route, assuming certain levels of performance in both the

fractionation and oxidation steps. A route beginning from com starch will probably not be as

competitive as a route using a starch containing waste stream. Peracetic acid is a reasonable candidate

to consider for further research.

5.1.14 Anthraquinone

From biomass:

Diene

Mixed Diels

Alder ANTHRAQUINONE benzoquinones cyclization

= Aci~.. LMW ~IOxid· I liquor --....--- preapltatlon --....--- lignin --....--- anon

t

~r~se ~I Fractionationl=~IOxidation I Diene

t t t ........ Diels~ Hemicellulose Cellulose Mixed Alder ANTHRAQUINONE

benzoquinones cydization

From petrochemicals:

Nitric

acid

-

ANTHRAQUINONE Benzoyl~

benzoic~

acid

Benzoyl ----I RID}"g I---ANTIlRAQUINONE benzoic c osure "7fIIIII""'"

acid

-

Sulfuric

acid

Styrene l[ijmltionI~'---"

99
Processes Compared: Anthraquinone, or anthraquinone-like products, can be produced from biomass

derived low molecular weight lignin, available either from kraft black liquor or the organosolv "clean

fractionation" process (section 5.2.1), by a two-step chemical sequence. The conversion proceeds with

oxidation of the lignin to a mixture of benzoquinones, followed by addition of a diene. Commercially,

anthraquinone is produced from phthalic anhydride and benzene, using aluminum chloride as a

catalyst. Another process, starting from styrene is known, and has come close to commercialization.

Other petrochemical-based routes to anthraquinone have much higher costs.

Raw Materials Cost Comparison: Two different sources of lignin, organosolv and kraft, were considered

as starting materials for the biomass-based route to anthraquinone and were compared to the two

petrochemical routes. The cost of raw materials for a process starting from organosolv lignin is

$0.592/lb, assuming yields of 40% and 50%in the two chemical steps, respectively. The cost using kraft

black liquor as the starting material gives a raw material cost of $0.836/lb, assuming yields of 30% and

90% in each of the two chemical steps respectively. The benzene-based route to anthraquinone has raw

materials costs of $l.98/lb, and the styrene-based route has similar costs of $l.(lO/lb. Comparing these

results gives the ratios

(AQ from benzene/AQ from organosolv) 1.98/0.592=3.34

(AQ from benzene/AQ from kraft) 1.98/0.836 =2.37

(AQ from styrene/AQ from organosolv) 1.00/0.592 =1.69

(AQ from styrene/AQ from kraft) 1.00/0.836 =1.20

and when a risk factor of 1.3 is included, theratios become

(AQ from benzenelAQ from organosolv) 3.34/1.3 =2.57

(AQ from benzene/AQ from kraft) 2.37/1.3 = 1.82

(AQ from styrenelAQ from organosol v) 1.69/1.3 = 1.30

(AQ from styrenelAQ from kraft) 1.20/1.3 = 0.92.

These large ratios indicate that a biomass-based route to anthraquinone could compete successfully

with current petrochemical routes. These results are based as closely as possible on actual laboratory

results increasing the reliability of this evaluation. A more in-depth analysis of these routes has been

carried out and is summarized in section 5.4.2of the report.

5.1.15 Acrylic Acid/Esters

From biomass:

~a~h, I l

sugar cane, Saccharification Fermsugarsentable or Cellulose .

,

IFermentation I

,

Lactic .,

acid

Thermal

dehydration

Methanol

100

Catalytic ____ dehydrogenation ---....-- ACRYLATES
Potato ~lFennentation I Lactate

waste salt

,

Alcohol

From petrochemicals:

Esterification ---lIIIIIIIo... Lactate ----",...-- ester

ACRYLIC

ACID

Oxygen

t

IPropylenel---~ ....__.. ACRYLIC

AOD

Processes Compared: A number of different biomass feedstocks have beensuggested as possible starting

materials for preparing acrylic acid, including potato waste, cheese whey, and blackstrap molasses.

Each of these materials give varying amounts of fermentable sugars, the preferred starting material for

acrylic acid production. The sugars can be fennented to lactic acid and thermally dehydrated to give

acrylic add (Antal, 1989). Alternatively, potato waste can be saccharified, and then fermented in the

presence of ammonia to produce an ammonium lactate salt that is esterified with an alcohol .to give a

lactate ester. The ester can be hydrolyzed to give acrylic acid and recover the alcohol for reuse. Acrylic

add is produced commercially from propylene by a two-stage oxidation process.

Raw Materials Cost Comparison: The raw material cost for producing acrylic add from petrochemicals

is $O.145/lb, assuming that propylene can be obtained for $0.16/Ib, and that the Yield of the oxidation

is 80%. Thermal production of acrylic add from lactic acid has a raw material cost of $O.366/lb because

of the high cost of lactic acid. This cost assumes a 75% Yield for the process. In contrast, the low

feedstock cost of potato waste (assumed to be zero) gives a raw material cost for direct potato waste

fermentation of $0.053lib, assuming 36% Yield. Comparing the petroleum-based process to the two

biomass routes gives the ratios

(thermal route) 0.145/0.366 =0.4

(from zero value potato waste) 0.145/0.076 = 1.91

and when a risk factor of 13 is included, the ratios become

(thermal route) 0.4/1.3 =030

(from zero value potato waste) 1.91/1.3 =1.47

The results of the potato waste analysis indicate that producing acrylic esters in this method has a

good chance of competing with acrylates currently produced by petrochemical means if the cost and

availability assumptions on potato waste can be verified. Production from the thermal route would be,

less competitive, given current feedstock costs.

Future Projections: Acrylic acid and its esters have a wide range of applications in polymer markets.

Further investigation of this methodology should be done to answer questions about the range of

acrylate esters that can be produced from different alcohols, and whether the lactate esters can be

converted into peroxy esters, compounds uses as polymerization initiators and in other applications.

101
5.2 Improved Production

A number of chemicals and materials have been identified that are currently produced from renewable

sources. These materials have the potential of serving as building blocks for end products that replace

those currently derived from petrochemicals. The production levels'of these materials are relatively

low, either because markets for their use have not been identified or because their cost is too high to

justify their use as starting materials for end products currently produced from petrochemical building

blocks. This portion of the evaluation describes the potential cost of these materials if new methods of

production could be developed. Identifying new, lower-cost routes for producing these materilzls will

suggest new applicaiions of renewable starting materials in markets traditionally dominated by

petrochemical derivatives. Recent work at NREL has resulted in a promising market opportunity for

the Alternative Feedstocks program and producing these materials - the clean fractionation process.

szr The NREL Clean Fractionation Process

Many of the chemicals or product families evaluated in the improved production category have a

demonstrated use in the marketplace (section 4.3), although they are more specialty oriented than

those materials in the direct substitution category. The common link between these chemicals is their

derivation from glucose or xylose. Conventional production of these two monomeric carbohydrates

normally uses com starch as the starting material for glucose and the 5-carbon sugars in corn cobs as the

starting material for xylose . Alternatively, these carbohydrates can be prepared from fractionating

lignocellulose, followed by converting the cellulose fraction to glucose and the hemicellulose fraction to

xylose (Figure 5.1 shows the derivation of different product families, from glucose and xylose, using

lignocellulosics as the starting feedstock). However, the corn-based route has historically proven more

economical.

Recent work at NREL has discovered a new process for the clean separation of wood into its constituents

cellulose, hemicellulose, and lignin, at efficiencies approaching 100% for each component. Because the

process is potentially proprietary, and patents are currently being filed, the results presented here will

not reveal the specific conditions under which this "clean fractionation" is obtained other than to note

that results have been obtained in small scale organosolv pretreatment experiments. However, the

results could be of broad scope and offer a promising market opportunity for the Alternative Feedstocks

program.

The most important result of this work comes out of a technoeconomic evaluation of its potential. This

process could potentially offer glucose and xylose at a cost substantially lower than other routes,

including the conventional com starch-based process. These results have a cascade effect, lowering the

costs associated with producing the related product families (Figure 5.1). The process also offers a low

cost source of glucose (fermentable sugar) for use in bioprocessing, suggesting a solid opportunity to

develop hybrid chemical/biochemical processes to products. Moreover, cellulose, the precursor to

glucose, is used in large quantities by the chemical industry. An efficient and lower cost process for

producing high purity cellulose would have an impact on a number of markets (section 4.3).

The most influential assumption in assessing clean fractionation is the availability of wood, delivered

as chips on a large scale to a plant site at a cost of $40/dry ton (discussed in more detail in section 3.1).

The ratios in this section compare the conventional biomass-based routes to the materials with new,

less expensive routes, based on the availability of cheaper raw materials. Of particular interest in

this section are new, more cost-effective routes to a number of carbohydrates, materials available

cheaply in large quantities, but possessing a high degree of functionality and structural complexity.

The raw materials cost contribution analysis for producing glucose and xylose from clean fractionation is

presented in sections 5.2.1.1 and 5.2.1.2, and a more detailed analysis, including projected operating and

capital costs, is given in section 5.4.3.

102
furfural

furfuryl alcohol

furan

tetrahydrofuran

xylitol

IXylose I<,

Fennentable

sugar for

bioprocessing

t sorbitol

____ mannitol

IGlucose I

I • ed \ grucemc aci

5-hydroxymethyl furfural

levulinic acid

formic acid

succinic acid

>

>

Cellulose

Hemicelluloses

----->

Clean

fractionation

Lignocellulosics

Lignin >

Anthraquinone

Other specialty

chemicals

Figure 5.1- Flowchart for Production of Chemical Families from Clean Fractionation

103
5.2.Ll Glucose

Glucose is a renewable building block that serves as a precursor to a variety of materials. The

evaluation compares the costs of producing glucose from four raw materials, lignocellulosic biomass, by

means of the new NREL clean fractionation technology, sugar cane, com starch, and wood by steam

explosion.

From lignocellulose:

Catalyst Solvent

Ligno- " I

cellulose

preparation

/'

Ugnin

--...- Cellulose

"

Hemicellulose

Acid or

enzymatic GLUCOSE

hydrolysis

From sugar cane:

gar cane

pressing

• 'ExtractiOn 1 GLUCOSE

Bagasse

Fromcorn:

Enzyme

,

Com -..1 Milling I-....~I uquefaction~

Enzyme

t

." ISaccharification I .. GLUCOSE

.0- "I

··,-,r

From steam explosion of wood:

Acid or

tic GLUCOSE ~YSiS

.. Hemicellulose

Cellulose +

I~~mgl ....__.. ~ISeparationl

104
Glucose from 1i&"ocellulosicbiomass

Glucose, in this case, is derived from hydrolysis of the cellulose fraction of the NREL clean

fractionation technology for lignocellulosic biomass. The advantage to this process is that all three

coproducts could be upgraded to commercial materials for use in different markets. The raw material

. cost contribution can be shared equally among the coproducts. A raw materials cost of $O.032/lb for

glucose results, assuming wood feedstock costs $40/dry ton and a yield of glucose from cellulose of 90%.

Glurose from suwcane

The cost of producing fermentable sugars (as glucose) was estimated by extrapolating information

collected as part of a report on producing ethanol by fermentation of sugar cane. A raw materials cost of

$O.08/lb (corrected to 1992) was obtained based on a cost of growing and harvesting sugar cane of

$O.OO6/lb (1978), in a plant designed to produce 12.6 million gallons of ethanol per year. Sugar

containing juice from sugar cane suffers from a short growing season and a limited shelf life, making a

constant rate of operation through the year difficult. This would be less of a problem in Hawaii where

harvesting can take place 10 months out of the year.

...:..: Glucose from com starch

Again, the cost of fermentable sugars (as glucose) was estimated from a report describing an ethanol

production facility designed to make 25 million gallons per year from dry milled com. Assuming com

costs $2.60/bushel, and a yield of 73% of sugars from com starch saccharification, a raw materials cost

of $O.05/Ib (corrected to 1992) for sugars from com was obtained. In contrast to the sugar cane process,

com can be stored through the year, assuring a constant production level of fermentable sugars.

Glucose from wood by steam explosiQn pretreatment

Glucose can also be prepared by pretreating wood in a steam explosion process. The information for the

calculations was provided from a series of engineering reports describing processes to produce glucose by

steam explosion, followed by enzymatic or acid hydrolysis of the cellulose produced. Assuming wood

feedstock costs $40/dry ton, and a yield of 32-39% of cellulose from dried wood, a cost of $O.056/lb can be

calculated. This value is an average of two different economic evaluations (A. D. Little 1985, Stone and

Webster 1987).

·1

.. ,

Comparative evaluation

From this information, a cost comparison similar to that used for direct substitution items can be

derived. Comparing the cost of glucose derived from sugar cane or com starch to that derived from

lignoceUulosics gives the ratios

(glucose from sugar cane/glucose from lignocellalosics) 0.08/0.032 = 2..50

(glucose from com starch/glucose from lignocellulosics) 0.05/0.032 = 1.56

(glucose from steam explosion/glucose from lignocellulosics) 0.056/0.032 =1.75

and when a risk factor of 1.3 is included, the ratios become

(glucose from sugar cane/glucose,from lignocellulosics) 2.50/1.3 = 1.92

(glucose from com starch/glucose from lignocellulosics) 1.56/1.3 = 1.20

(glucose from steam explosion/glucose from lignocellulosics) 1.75/1.3 =1.35.

Wood feedstock at S40/dry ton is allocated on a weight basis to all three coproducts from the

fractionation <Cellulose, xylose, and lignin). This assumes that each of the coproducts can be upgraded

to useful products that the market will consume.

105
. '.

The high value of these ratios, derived from actual laboratory results, indicates that clean

fractionation could provide raw materials at a cost considerably lower than from conventional sources,

providing that markets are found for consumption of all three coproducts. This process should be

recommended for further investigation and application to synthesizing new materials, such as cellulose

polymers such as acetates, propionates, rayons, etc., that require a high purity cellulose feed.

5.2.1.2 Xylose

Production Methods:

Catalyst Solvent

" I

u

cef'uiose • ~nosolv • Hemicellulose • XYLOSE

preparation fractionation

/'

lignin

"

Cellulose

Acid

Bagasse • • XYLOSE reactor

I

Cellulose

"

lignin

Xylose is produced by acid treatment of pentosans in hgnocellulosics. Two processes were compared:

converting the hemicellulose fraction derived from the NREL clean fractionation technology to xylose

in a coproduct process with cellulose and lignin, and converting bagasse to xylose, using technology

similar to that practiced by Quaker Oats in their process to make furfural.

Producing xylose from clean fractionation is projected to give xylose at a cost of $O.032/lb, assuming all

three coproducts (cellulose, xylose, and lignin) share costs on a pound basis, and can be upgraded to

useful products. If only two of the coproduets can be consumed, the projected xylose cost rises to

$O.034/lb. By comparison, xylose produced from bagasse hasa raw materials cost of $0.09/lb, assuming

bagasse is delivered at $40/dry ton, and gives an overall yield of xylose of 75%. Comparing these

results gives the ratios

<bagasse/lignocellulose, 3 eoproducts) 0.09/0.027 =3.33

<bagasse/lignocellulose, 2 coproducts) 0.09/0.034 = 2.65

and when a risk factor of 1.3 is included, the ratios become

<bagasse/lignocellulose, 3 coproducts) 3.33/1.3 =2.56

<bagasse/lignocellulose, 2 coproducts) 2.65/1.3 = 2.04

106
These high values indicate that producing xylose by clean fractionation could compete very favorably

with xylose prepared by conventional processes, and serve as a new low cost starting material for

producing furfural, furfuryl alcohol, and tetrahydrofuran.

5.2.2 5-Hydroxymethylfurfural

Production method:

Starch, I · I Fermentable

sugar cane, Saccharification su ars or cellulose g .........__..

t

5-HYDROXYMETHYL

FURFURAL

'11

Levulinic,

formic

acids

5-Hydroxymethylfurfural is a material that can be obtained by the controlled acidic dehydration of

glucose or fructose. Further acid catalyzed dehydration leads to coproduction of levulinic and formic

acids. A number of different materials could be derived from this functional monomer. Two sources of

starting glucose (fermentable sugars> were considered in the comparison: glucose derived from com

starch, and glucose derived from the NREL clean fractionation. The raw material cost of 5-

hydroxymethylfurfural from corn starch derived glucose is SO.102/1b, assuming a 70% yield of 5-

hydroxymethylfurfural from glucose dehydration, and a glucose cost of $0.05lIb. In comparison, the

cost of 5-hydroxymethylfurfural from clean fractionation glucose is $$0.065lib, assuming a glucose cost

of $O.032/Ib. Comparing the two glucose starting materials used gives the ratio

0.10210.065 =1.57

and when a risk factor of 1.3 is included, the ratio becomes

157/1.3 =1.21.

This ratio indicates that glucose from clean fractionation can serve as a significantly lower cost

feedstock for producing 5-hydroxymethylfurfural, and perhaps stimulate its consideration as an novel

chemical building block.

S.2.3LevulinidFormic Acids

Production method:

Starch, I I Fermentable

sugar cane, Saccharification su ars or cellulose g

LEVULINIC,

---....-- FORMIC

ACIDS

t

5-Hydroxymethyl

furfural

Production method: Levulinic and formic adds can be produced as coproducts in a 72/28 mixture with 5-

hydroxymethylfurfural from the controlled acidic dehydration of glucose or fructose.

107
Raw Material Cost Comparison: The comparison was made between producing levulinic and formic

acids from com starch derived glucose, and glucose prepared by the NRELclean fractionation process.

Levulinic acid can be produced from com starch derived glucose at a raw material cost of $O.l64/lb,

assuming that glucose is available at SO.OS/lb, and a 70% yield in the conversion step. In comparison,

levulinic acid prepared from clean fractionation glucose has a raw material cost of SO.10S/lb, assuming

the same yield performance and a glucose cost of $O.032/lb. Comparing these values gives the ratio

0.164/0.105 =1.56

and when a risk factor of 1.3 is included, the ratio becomes

1.56/1.3 = 1.20.

This value indicates that producing levulinic acid from clean fractionation glucose could offer a lower

cost product, increasing its use as a chemical feedstock.

Formic acid can be produced from com starch derived glucose at a raw material cost of $O.064/Ib, given

the same yield and cost assumptions as for levulinic acid. The cost from clean fractionation glucose is

$O.041/lb. Comparing these values gives the ratio

0.064/0.041 = 1.56

and when a risk factor of 1.3 is included, the ratio becomes

1.56/1.3 =1.20.

The primary competition fOT formic acid will come from the petrochemical process. Current costs of

petrochemical derived formic acid is about $0.40 - 050/lb.

5.2.4 Succinic Acid

Production method:

From biomass:

=~, ~I Saccharificationl

or cellulose

Fermentable ... Controlled

sugars dehydration

5-Hydroxymethyl

furfural

From petrochemicals:

Levulinic, formic - ...

acids

SUCCINIC

ACID

Maleic , I anhydride .. Reduction

Succinic

anhydride

108

.. JHydrolysis I ~~i5INIC
Production Methods: Succinic acid can be prepared from biomass from levulinic acid generated as a

coproduct with formic acid and 5-hydroxymethylfurfural by dehydration of glucose. The commercial

approach to succinic acid proceeds by reducing maleic anhydride (prepared by butane oxidation) to give

succinic anhydride, followed by ring opening hydrolysis to give succinic acid.

Raw Material Cost Comparison; The cost of succinic acid prepared from biomass is projected to be

$0.09/Ib, assuming an 83% yield for the oxidation of levulinic acid, and taking credit for the coproducts

produced. The cost of succinic acid from petrochemicals is SO.II/lb, assuming that maleic anhydride is

available at $O.I25/lb, and the reduction and hydrolysis proceed in overall 95% yield. Comparing the

biomass route to the petrochemical route gives the ratio

0.11/0.09 =1.22

and when a risk factor of 1.3is included, the ratio becomes

1.22/1.3 =0.94.

This value indicates that producing succinic acid from biomass could compete with that derived from

petrochemicals. Further investigation should be performed on the levulinic acid oxidation to verify

the reported performance numbers.

5.2.S Gluconic Acid

Production method:

Air or

oxygen

Glucose lOxiton 1---'- GLUCONIC

ACID

Gluconic acid, produced by the oxidation of glucose, has its largest applications in the food and

pharmaceutical industries. It has the potential of serving as a building block for a variety of materials

if appropriate markets can be defined and a low cost source of glucose can be obtained.

Because of the technical simplicity and high yield (nearly quantitative) of the current route to gluconic

acid, improvements will most likely be realized if a lower cost source of the glucose starting material is

discovered. The clean fractionation of lignocellulosics being investigated at NREL holds the

possibility of providing cellulose (the precursor to glucose) at a cost lower than other currently

practiced methods. Thus, the costs of gluconic add from two low cost glucose sources (com starch and

lignocellulose) were compared. The details for the cost contribution of glucose are given in section 5.2.1.

Glucosefrom Com Starch

Glucose from com starch is estimated to be available at $0.049/lb. The raw material cost contribution to

the cost of gluconic acid production is projected to be $O.058/lbl assuming oxygen is available at

$0.10/lbl and the oxidation proceeds in 95% yield.

Glucose from LiiWOCellulosics

Producing glucose from the cellulosic fraction of lignocellulose derived. from clean fractionation is

projected to cost $0.032/lb. The raw material cost contribution to the cost of gluconic acid production is

projected to be SO.040/lb, assuming oxygen is available at SO.10/lb, and the oxidation proceeds in 95%

yield.

109
Comparing the two costs gives the ratio

(com starch/lignocellulose) 0.058/0.040= 1.45

and when a risk factor of 1.3is included, the ratio becomes

1.45/1.3 = 1.12.

This ratio suggests that changing the source of the glucose feedstock from com starch to lignocellulose

could result in a significant cost improvement in producing gluconic acid.

5.2.6 Sorbitol

Production method:

Hydmgen

Glucose --II.~ SORBITOL .

Sorbitol is currently made in very high yield from the catalytic hydrogenation of glucose. As in the

case of gluconic acid, the technology for producing sorbitol is simple and affords product in high yield.

The greatest chance for improving the technology resides in the identifying a less expensive source of

glucose. Oean fractionation technology potentially offers the most inexpensive source of glucose of

those studied. Two sources of glucose were compared for this evaluation.

Glucose from Com Starch

Producing sorbitol from reduction of com starch derived glucose is projected to give a raw material cost

contribution of SO.058/lb, assuming that hydrogen is available at SO.54/lb, the reduction proceeds in

95% yield, and not including the cost of the catalyst.

Qucose from U~e1Iu1ose

Producing sorbitol from reduction of lignocellulose derived glucose is projected to give a raw material

cost contrfbution of SO.034/lb, again assuming that hydrogen is available at SO.54/lb, the reduction

proceeds in 95% yield, and not including the cost of the catalyst.

A comparison of the two sorbitol costs gives the ratio

(com starch/lignocellulose) 0.058/0.034 =1.71

and when a risk factor of 1.3 is included, the ratio becomes

1.71/1.3 = 1.31.

This ratio suggests that changing the source of the glucose feedstock from com starch to lignocellulose

could significantly improve costs for producing sorbitol.

110
5.2.7 Mannitol

Production method:

Hydrogen

Glucose catalytic Isoglucose isomerization

~MANNITOL,

SORBITOL

Mannitol is available in about 30% yield from the catalytic hydrogenation of isoglucose derived by

molybdate catalyzed isomerization of starch derived glucose. The remainder of the product mixture is

sorbitol. Separation is normally not a problem because mannitol can be selectively crystallized from

solution. The greatest opportunity for process improvement in mannitol production would arise from

developing a more selective process (i. e., a lower proportion of sorbitol in the sucrose/fructose reduction

mixture) along with a lower cost source of starting material, for example, glucose from cellulose derived

from the NREL clean fractionation technology. The latter possibility has been examined by comparing

the raw material cost for mannitol production from two different glucose sources.

Glucose from Com Starch

Producing mannitol from reduction of com starch derived glucose is projected to give a raw material cost

contribution of SO.065/1b, assuming that hydrogen is available at $O.54/lb, a com starch cost of

$O.05/lb, and not including the cost of the catalysts.

Glucose from Lilmocellulose

Producing mannitol from reduction of lignocellulose derived glucose is projected to give a raw material

cost contribution of SO.043/1b, again assuming that hydrogen is available at SO.54/lb, glucose is

available from dean fractionation at SO.032/lb,and not including the cost of the catalyst.

Comparing the costs of mannitol from the two different sources gives the ratio

(corn starch/lignocellulose) 0.065/0.043 = 1.51

and when a risk factor of 1.3 is included, the ratio becomes

1.51/1.3=1.16.

This ratio suggests that changing the source of the glucose feedstock from com starch to lignocellulose

could significantly improve costs in producing mannitol.

5.2.8 Xylitol

Production method:

Hydrogen

Xylose

111

- ..... XYLITOL
Xylitol can be produced in high yield by the catalytic reduction of xylose. As with other similar

sugars, the process for its production is simple, and proceeds in high yield. Any improvements will

come from reducing the costs of the starting material. A comparison of xylitol costs as a function of the

method used for xylose production can be made. Two sources of xylose were compared: xylose prepared

by conventional means from bagasse, and xylose prepared by acid treatment of the hemicellulose

fraction of lignocellulose from the NRELclean fractionation technology.

Producing xylitol from reduction of bagasse derived xylose is projected to give a raw material cost

contribution of SO.1oo/lb, assuming that hydrogen is available at SO.54/lb, and not including the cost of

the catalyst. By comparison, xylitol produced by reduction of lignocellulose derived xylose will have a

raw material cost contribution of $O.037/lb. Comparing these results gives the ratio

<bagasse/lignocellulose) 0.103/0.037=2.78

and when a risk factor of 1.3 is included, the ratio becomes

<bagasse/lignocellulose) 2.78/1.3 =2.14.

This high value indicates that a significant cost advantage could be realized for producing xylitol from

lignocellulose derived xylose.

5.2.9FurfUral

Production methods:

.. ISeparation I .. FURFURAL

Acetic,licacids

.. FURFURAL

Dilute

--... -~ acid

hydrolysis

Xylose --I"~ Dehydration --I~

Corncobs

or bagasse

IDreDaration

lignocellulose

preparation

t

-....;j... FURFURAL

Cellulose,

lignin

Furfural is produced commercially by the acid dehydration of com byproducts, or similar

lignocellulosics, and is a starting material for such high volume organics as adipic acid, maleic

anhydride, and butanol. A coproduct fuels and chemicals process, generating ethanol and furfural from

acid hydrolysis of lignocellulose, was investigated by NREL a number of years ago. The study

estimated the potential future market for three commodity derivatives that could be competitively

produced from furfural using existing technology. The results of the study are shown below.

Chemical

Furfural

Adipic Acid

Maleic Anhydride

Butanol

Price ($/lb)

0.57

0.33

0.12

0.09

Total Furfural

Demand (tons/yr)

63,492

517,913

723,810

1,521,088

Total Revenue

(millions of $)

79.8

377

192

302

112
The price of furfural was projected to drop over a period of about 10-15 years, as the volume of ethanol

produced from the plant increased. As the price reached the levels shown, furfural would become a

competing starting material for producing the chemicals shown in the first column, giving revenues as

shown. A coproduct ethanol/furfural process could be an alternative source of adipic acid, maleic

anhydride, and butanoland should be investigated. further.

A raw material cost comparison can be made for furfural by comparing a furfural process based on xylose

starting material derived from bagasse using conventional technology, versus xylose derived from the

NREL clean fractionation process. Furfural can be produced from bagasse-derived xylose at a raw

material cost of $O.lO/lb, assuming a feedstock cost of $40/dry ton, and an 85% yield in the conversion.

In comparison, the raw material cost for furfural derived from clean fractionation xylose is $O.062/lb,

assuming that xylose is available at SO.032/1b and the conversion proceeds in 85% yield. Comparing

these values gives the ratio

0.1/0.062 =1.61

and when a risk factor of 13 is included, the ratio becomes

1.61/1.3 =1.24.

This value indicates that clean fractionation technology offers a lower cost source of furfural and could

increase its value as a chemical feedstock for materials currently produced from petrochemicals.

5.2.10 Furfuryl Alcohol

Production methods. from com or bagasse:

lIIIo.. FURFURYL

--II.. ALCOHOL

FURFURYL

ALCOHOL

--... Furfural

, Hydrogen~ Reduction 1

- ....~~ J Dehydration I-....~~ Furfural • IReduction I •

HydL

Xylose

Com cobs

or bagasse

aration

From Xylose:

FURFURYL • I ALCOHOL Xylose Dehydration I-.... Furfural

• 1Redrnl

Hydrogen

Processes Compared: A major portion of the domestic furfural production is reduced in high yield to

give furfuryl alcohol, an important component for the producing furan resins. The furfural market has

been static for a number of years, but developing a new, cheaper starting material could give new

impetus for its use. The NREL clean fractionation technology can provide inexpensive xylose, a starting

material for furfural/furfuryl alcohol.

113
I .

Raw Material Cost ComJ?!lrison: The raw material cost for producing furfuryl alcohol from bagassederived furfural is $O.116/lb, assuming furfural costs SO.lO/lb (including coproduct credits), and a yield

in the reduction step of 95%. In comparison, the cost of furfuryl alcohol from clean fractionation xylose

is SO.066/lb, assuming furfural costs SO.062/lb when produced from xylose, and a 95% yield in the

reduction step. Comparing the bagasse route to the xylose route gives the ratio

0.116/0.066 =1.76

and when a risk factor of 1.3 is included, the ratio becomes

1.76/1.3=135.

This value indicates that producing furfural would benefit by a change of starting material from

bagasse to clean fractionation xylose.

5.2.11FuranlI'etrahydrofuran (TIfF)

From petrochemicals:

Hydrogen

n-Butane lOxidation

From biomass:

Maleic ., anhydride

t ., JReduction ~TETRAHYDROFURAN

Xylose IDehydration I • Furfural

t

Foran

Hydrogen

t

• IReduction I~TETRAHYDROFURAN

Processes compared: Almost all THF is produced today from petrochemicals via 1,4-butanediol

cyclization, acetylene/formaldehyde reaction (the Reppe process), and other processes. Successfully

developing a process based on butane oxidation could potentially be a large scale producer of lHF and

was chosen for the comparison. The biomass-based route to THF begins with xylose, available from

fractionation of lignocellulose. Tetrahydrofuran was once exclusively prepared from xylose, via

converting and reducing furfural, available from agricultural wastes (corn cobs). Today, only about 10%

of all THF production starts with furfural, since routes from 1,4-butanediol, and acetylene and

formaldehyde cost less. However, the NREL clean fractionation technology has the potential to offer

a low cost form of very pure xylose from lignocellulose. In addition, recent work at NREL has identified

a high yield catalytic method for the converting furfural into furan.

Raw Materials Cost ComJ?!lrison: The raw material cost for the producing THF from petrochemicals is

projected to be SO.lOS/lb, assuming that maleic anhydride is available at SO.125/lb, hydrogen is

available at SO.54/lb, and the reduction proceeds in 90% yield. The raw material cost contribution for

tetrahydrofuran produced using clean fractionation xylose as the starting material is SO.117/lb,

114
assuming that the xylose is available for $O.032/lb, converting to furfural proceeds in 85% yield, and

subsequent conversion of furfural into tetrahydrofuran proceeds in 80% yield. Comparing these results

gives the ratio

O.1~/O.117 = 0.92

and when a risk factor of 1.3 is included, the ratio becomes

0.98/1.3 =0.71.

This ratio suggests that THF produced from xylose could have a chance of competing with

petrochemical derived THF, if the prices of the raw material feedstocks change, i. e., if the price of

lignocellulosics drops or the price of petroleum rises.

5.2.12 PolyhydroxybutyrateIPolyhydroxyvalerate (PHBIPHV)

Production Methods:

From &lucose and propionic acid:

Glucose ...............

Propionic

acd

From synthesis &as:

Microbial

polymerization lSeparation I POLYHYDROXYBUTYRATE,

POLYHYDROXYVALERATE

Microbial

polymerization

Lignocellulose IGaSifierl ~I Refonner I preparation "

t

Syn

gas

- ....~~ JSeparation I ..._--_.. POLYHYDROXYBUTYRATE, ., POLYHYOROXYVALERATE

Processes compared: PHB and PHV, thermoplastic polyesters, can be prepared microbiologically by

reaction of glucose and propionic acid in an aqueous medium. More recently, a microbe has been

identified that can produce PHB/PHV directly from SYnthesis gas. Biomass derived synthesis gas has

been described as a cost effective starting material for producing acetic acid (section 5.1.12).

Raw Material Cost Comparison: The microbial polymerization produces about a 70/30 mixture of

PHB/PHV, but for simplicity, the evaluation wasperformed assuming pure PHB would be produced.

The raw materials for producing PHB/PHV were assumed to be glucose and purchased propionic acid.

Assuming a cost of $O.10/lb for glucose, $O.40/lb for propionic acid, and a polymerization yield of 26

wt%, a raw material cost contribution of $058/lb was derived. In comparison, the raw material cost for

producing PHB/PHV from syn gas is $O.10/lb, assuming wood feedstock costs $40/dry ton, and a 32 wt%

yield of PHB/PHV. .

115
It is possible that conditions can be developed for in situ production of the propionic acid anaerobically

from glucose. This possibility was not addressed. Comparing the glucose route to the syn gas route gives

the ratio

058/0.10 = 5.8

and when a risk factor of 1.3 is included, the ratio becomes

5.8/1.3 = 4.46.

If a less expensive source of glucose were used, the ratios would drop accordingly. This large value

indicates that PHB/PHV could be produced much more economically from biomass derived synthesis

gas than from a glucose/propionic acid starting material. Further investigation of this process is

warranted, especially in separating the polymer from the microbial solution.

5.3New Building BlockslProducts

5.3.1 LevogIucosan

Production method:

Others

Lignocellulose

preparation

Dilute Fast acid .. pyrolysis hydrolysis

t

Soluble

fraction

• ISeparation I LEVOGLUCOSAN

t

Phenolics

Levoglucosan can be produced by the pyrolysis of acid treated lignocellulosics in 20-30% yield.

Levoglucosan has traditionally been an expensive specialty material, but process improvements suggest

that costs can be significantly reduced. Specific markets for using this new building block are being

defined by industry (ACS Symposium on Levoglucosan and Levoglucosenone, 1992). If low cost

levoglucosan can be obtained, it could serve as a starting material for producing new polymers or high

value materials, and as a raw material for some of the sugar alcohols described above. A comparison of

the raw materials cost for the production of levoglucosan from lignocellulosics versus starch has been

carried out. Raw materials cost for producing levoglucosan from wood is estimated at $O.054/lb,

assuming wood feedstock costs $40/dry ton, and a 22% yield. In contrast, producing levoglucosan from

starch has a raw materials cost of $0.38/lb, assuming com starch to be available at SO.08/lb. The

lignocellulosic pyrolysis has a significant cost advantage that is aided by sharing the raw materials

cost with coproduct phenolics. Levoglucosan is currently considered an important raw material for

further investigation.

116
5.3.2Cellulose (Kraft)1Anthraquinone

Production method:

"Oxidation I I Diels Alder

reacnon

CELLULOSE

PULP

t

Wood IKr~ pulpmg I..

,

Black

liquor

10% 1

sidestream ,

IFractionation I

Recovered

chemicals

Diene

• ANTHRAQUINONE

An alternative method investigated for the production of anthraquinone from biomass derived lignin

envisions building a small anthraquinone production facility on the site of an existing kraft mill. The

operation would be supplied with a 10% sidestream of kraft black liquor and convert it to

anthraquinone. The remaining black liquor would be treated as usual to provide fuel and recover

pulping chemicals for the operation. The produced anthraquinone would be fed into the operation as a

catalyst. Investigating the costs of such an operation reveal that the scale would be too small to be

economical. An alternate scenario envisions building a single standalone anthraquinone plant in a

location convenient to a number of pulp mills. The plant would receive black liquor and convert it not

only to anthraquinone, but to other lignin derived products. This allows a much larger plant to be built

and realize the economies of scale. The details of this evaluation are found in section 5.4.1.

5.3.3 Cellulose (OIganoso}v)!Anthraquinone

Production method:

Cellulose

;~~~se ~Fractionationl ~=

Hemicellulose

+

Joxidation I

mixs:l

benzoquinones

117

Diene

,

Diels

Alder ~ANTHRAQUINONE

cyclization
As described in section 5.1.14, anthraquinone can be derived from organosolv fractionation of

lignocellulosics by chemically transforming the lignin stream of the process, The process also offers two

other product streams for use as chemical feedstocks. The cellulose fraction can be used as a feedstock

for lower grade paper products, or blended with other celluloses, for example, from a conventional kraft

operation. The ability of this clean fractionation process to provide three products that can be absorbed

by the chemical market allows raw material costs to be shared between the products, resulting in a

lower overall raw material cost. This process is described in greater detail in section 5.4.1.

5.3.4 Starch Plastics

Production method:

Starch t '-IExtruder l

Polystyrene/ /

maleic-anhydride

copolymer

Water

STARCH

~GRAFT

COPOLYMER

A family of biodegradable graft copolymers can be prepared from the coextrusion of starch and a

polystyrene/maleic anhydride copolymer. This product could be of use in producing new thermoplastic

materials and compatibilizers for blends of cellulose and starch with plastics. The process evaluated

was developed by Ramani Narayan and coworkers at the Michigan Biotechnology Institute. Because of

proprietary information involved in the work, no details are presented here but overall costs are given

in section 5.45.

5.3.5 Acetylated Wood

Production method:

Lignocellulose

preparation

Acetic

anhydride ..........---

Acetylation

ctor

Acetic

acid

Acetic

anhydride

recovery

t

'Separation ~OJying I

t

Acetic

acid

recovety

Water

ACETYLATED

WOOD

Treating wood with acetic anhydride gives a material that shows much greater dimensional stability

and resistance to biological degradation, properties that significantly broaden the potential market

118
'-.

1

applications of products made from acetylated wood. The process also produces acetic acid as a

coproduct, the cost of which can be taken as a byproduct credit in calculating process economics. The

details of the evaluation are described in section 5.4.4. Rowell describes wood acetylation in detail

(Rowell 1992). The technoeconomic assessment of this concept was described by Chum and Power (H. L.

Chum and A. J. Power in Rowell 1992)for two cases of particles and fibers.

5.4 Selected Detailed Production Cost Estimates

Evaluations based on raw materials cost contributions provide an initial screening method to determine

whether a given chemical could be produced in a cost effective manner from renewable feedstocks.

However, we have also carried out a more in-depth technoeconomic evaluation of the most promising

candidates identified by raw materials cost comparison through preliminary plant design to estimate

capital and operating costs. Combining these costs with the raw material costs of the process chemistry

leads to a total amortized production cost of the material. This section summarizes the results of these

more detailed screenings of several of the most promising candidates. A tabular summary of the major

cost contributors to the amortized production cost of each is given in Table 5.2.

The choice of which chemicals or processes to evaluate in this section was based on several criteria, but

two are most important. First, the ratio of the raw material cost contribution, petrochemical/biomass,

needed to be favorable. As described in section 4., the screening, based on raw material costs, serves as a

"pointer" to identify opportunities with particular promise. However, a favorable ratio also needs to

be combined with sufficient process information, based on actual laboratory or development experience,

to make the more detailed evaluation credible. For example, the petrochemical/biomass ratio for

vinyl phenol (section 5.1.8) is 7.40, the highest of all the candidates evaluated. However, the process

parameters for vinyl phenol production are only beginning to be defined. Considerable laboratory work

is still needed before a reasonable projection of capital and operating costs can be made. Conversely,

producing phenolics by pyrolysis had a much lower ratio, 1.17, but is considered an excellent candidate

for a more detailed analysis. Many years of experience at NREL in running the process on a multipound

scale has given process parameters that can be used with confidence in preparing a detailed economic

projection.

The processes described in this section are listed according to category (direct substitution, improved

production, new building blocks/products). We believe that each of these chemicals or processes

represents a promising opportunity and no attempt is made to favor one over another. The reader is

expected to bring his or her own criteria to these evaluations and decide if any of the processes fits

their current needs.

5.4.1General Information

Each of the evaluations summarized in this section followed the same general procedure:

a. Drawing the flow diagram (for each new base case)

b. Calculating the material balance

c. Calculating the energy balance

d. Estimating equipment sizes

e. Estimating the capital costs

f. Estimating the operating costs

g. Evaluating economics and potential profitability

h. Defining and evaluating of variations on the base cases

i. Developing conclusions and recommendations

This group of tasks is commonly known as preliminary chemical process design; it is significantly more

rigorous than "back-of-the-envelope" approaches, but is short of capital budget quality work. The

degree of detail in each step can vary considerably, usually depending on the availability and quality

119
Table 5.2- Summary of Key Ecomomlc Contributors to Amortized Production Costs from Phase II Analysis

Process Evaluated Capital Investment Annual Production

(millions of dollars) (millions of pounds) Raw Materials (S/lb) Capital Costs <S/lb) Operating Costs(S/lb) Total Cost(S/lb)

Anthraquinone

from kraft lignin 10.7 19.3 0.836 0.084 0.125 1.045

from organosolv 12.7 19.3 0.592 0.098 0.125 0.815

Phenolics from Fast 34.0 140 0.0941 0.037 0.034 0.165

Pyrolysis 0.0242 0.032 0.042 0.098

Phenolics from Wood 33.8 140 0.1661,3 0.048 0.036 0.250

Phenolatlon 0.1532,3 0.048 0.036 0.237

Clean Fractionation

3 coproducts, cellu- 54.6 1,248 0.032 0.006 0.018 0.056

lose, hemicellulose,

lignin

Acetylated Wood

Particle Feedstock 30.1 500 0.0894 0.004 0.004 0.097

Fiber Feedstock 46.4 500 0.0894 0.005 0.017 0.111

Veneer Feedstock 44.4 500 0.0894 0.005 0.017 0.111

Starch Plastics

Base case 1 17.2 10 0.62 0.22 0.63 1.47

Base case 2 7.7 10 0.62 0.13 0.16 0.91

Base case 3 2.8 10 0.71 0.04 0.084 0.83

Notes: 1Wood chips purchased at $40/dry ton

2Wood chips purchased at S10/dry ton

3Phenolation agent is 20% distilled phenolics fraction (or phenolics/neutrals oils) at $20/ton transfer cost

"Includes byproduct credit of $O.055/lb
of basic process chemistry information. Approximate, short-cut design and costing methods are used

because they conserve time and are more than adequate to identify areas for further research or more

detailed calculation. In addition, the type of preliminary design and economic analysis described here

can direct research time and funding to those areas that have the most impact on the process economics.

Because process design is an iterative process, these evaluations are part of a continuing succession of

increasingly refined., focused, and detailed designs. The results of this study could be used to convey

most of the basic infonnation industrial developers of chemicals from renewables need to make in-house

studies of potential long-term profitability in terms of their proprietary business plans.

5.4.2Detailed Process Analysis - Anthraquinone (AQ) from Low Molecular Weight Lignin

The first evaluation, a technoeconomic investigation of producing AQ from lignin, is.presented. in more

detail only to give a sense of the proces~ and the salient features used in developing these more

detailed evaluations. AQ is of potential use as a pulping catalyst in the pulp and paper industry, but is

not yet widely used because its cost is too high (about $4.QO-$4.50/lb). The key features to note are the

development of possible overall approaches to AQ (development of "base cases"), the assumptions

necessary to prepare the basecases, and the economic data that arises from evaluating the base cases.

5.4.2.1Definition of Process Chemistry

The most important portion of the evaluation is a clear definition of the process chemistry, because all

projections depend on the yield, efficiency and number of steps required to transfonn a renewable

feedstock into a given chemical. The block diagrams describing the process chemistry of the lignin-toAQ process were presented in section 5.1.14. The following perfonnance assumptions were made:

For the process based on organosolv lignin, it is assumed that:

1. The LMW ligninwill be obtained directly from an extraction/solvent recovery system of an

organosolv pulping mill (using the NREL clean fractionation technology) to give a net

delivered cost of SO.016/lb, after S300/ton credit for pulp and SO.025/lb credit (fuel) for

hemicellulose and extractives.

2. A 40% chemical yield of benzoquinones will result in the first step of the process upon

oxidation of LMW lignin.

3. The oxidation will proceed. with 10% losses of N02, the chosen oxidant for the evaluation.

4. A 50% chemical yield of AQ or AQ like materials will occur upon reaction of the

benzoquinones with the chosen diene for the evaluation, isoprene.

5. The reaction of isoprene with the benzoquinone mixture will occur with 50 wt % efficiency.

For the process based on kraft lignin, it is assumed that:

1. The lignin raw material is obtained by diverting a 10% sidestream of concentrated black

liquor from seven 1500 tpd kraft pulp mills.

2. LMW lignin will be recovered at each mill by ultrafiltration from concentrated kraft black

liquor (35% total solids) to give a filtrate containing 25% of total solids fed, ·72% of which is

LMW lignin; the LMW lignin will be recovered as a dry product via flash drying and shipped

to a central AQ plant at a total delivered cost, derived from approximation from past studies of

about $O.18/lb, that includes the various combinations of extraction (conventional and/or

supercritical), acid precipitation, and drying operations that are required.

3. A 30% chemical yield of benzoquinones will result in the first step of the process upon

oxidation of LMW lignin.

4. The oxidation will proceed with 10% losses of N02, the chosen oxidant for the evaluation.

5. The benzoquinones will be converted. to AQ or AQ like materials in 80% chemical yield.

6. Converting isoprene will proceed with 50 wt % efficiency.

121
5.4.2.2Definition of Base Cases

Laboratory results obtained to provide information for this evaluation suggested defining two base

cases for technoeconomic evaluation. The first is based on organosolv lignin and the other is based on

using kraft lignin as a starting material. All base cases generally follow the two-stage process

described in section 5.1.14. The primary difference between the black liquor and the organosolv case is

in the lignin processing stage. The organosolv case proceeds by separating and using a LMW lignin

fraction, produced directly using the NREL clean fractionation technology. Note that by definition

each of these base cases offers broad foundations for further discussion.

Within each base case is the ability to manipulate the evaluation for different possible operating

scenarios and give the answers to various "what-if"questions such as:

a. What performance, i.e., efficiencies, rates, costs, etc., must this process achieve to be a

commercial success?

b. Can the required performance be accomplished without violating fundamental

limitations, such as the laws of thermodynamics?

c. What additional developments are needed to achieve the required performance?

d. What are the prospects for improvements in the process?

All cases describe large-scale, stand-alone plants, sized to supply AQ by distribution to a significant

part of the entire pulping industry, and are based on built-up process flow diagrams, principal stream

material balances, and preliminary major equipment design.

A plant capacity basis of 19,300,000 lb/year of AQ was developed and used for each base case as a

representative large capacity that would supply a significant part of the pulping industry. A capacity

in the range of 19,300,000lb/year of AQ was considered a reasonable basis because the ultimate AQ

demand of the industry could be in the 100,000,000 lb/year range. The scale of 100,000,000 lb/year of

AQ in a single plant located in the southeastern United States is based on the assumption that half of

all Canadian and United States suHate pulp production would convert to AQ using 0,1% of AQ based on

wood feed. The basis is projected to be 50,000,000 tons per year (tpy) of pulp in the late 19905, with

wood feed of 100,000,000 tpy, assuming 50%yield of pulp.

A number of other operating assumptions are necessary to complete this evaluation and are shown in

Table 5.3. While certain specific values for these parameters may differ from evaluation to

evaluation, the table gives a sense of the types of information used in these more detailed evaluations.

5.4.2.3 Results of Evaluation

Completing a more detailed process evaluation gives a number of useful pieces of information. Figure

5.2 shows a comparison of the projected raw materials costs (calculated in section 5.1.14) of the two base

cases studied to the projected amortized production cost of AQ. Tables 5.4 and 5.5 summarize the

overall projected raw material, capital, and operating costs for the base cases.

5.4.2.4 Evaluation of Competing Routes to AQ

A more detailed analysis can project the amortized production costs of competing routes to AQ and give

an indication of how a biomass based route would fit into the market. Five potential petrochemical

based competitors were identified from the open and patent literature and were subjected to the same

detailed process analysis as AQ. The results of the evaluation are summarized in Figure 5.3, and the

processes evaluated are shown in block form in Figure 5.4. Overall, this more detailed analysis

indicates that AQ-from-lignin is a highly promising candidate for further R&D investigation, The

process offers an approach to a potentially useful material at a projected cost substantially less than

other routes.

122
Table 5.3- Additional Assumptions for Process and Capital Cost Evaluations

Zero time construction period.

Timing of investment

Interest rate during construction

Plant capacity factor

Long-tenn return on investment

Equity

Source of financing

Income taxes

Timing of costs

Working capital

Debt recovery

Plant lifetime

Base rate, salary

Labor burden (fringes)

Administration and general overhead

Utilities and Chemicals - Unit Costs

Electric power

Steam, 100 psig

Cooling water

Process water

LMW lignin, Organosolv

LMW lignin, Black Liquor

Methanol

Nitrogen dioxide

Oxygen

Isoprene

Residual organics (fuel)

All investments occur at start of construction.

Zero, because of zero construction time.

Typically 0.9, although it may be set to suit the

system.

15% for all systems before taxes. Sensitivity of

. price to higher returns will be investigated later

. when process is better defined.

None; all capital is borrowed.

All money obtained at the same interest rate.

None; analysesare for production costs only.

Operating expenses paid at end of year; payments

to debt paid at end of year.

Available at completion of construction, and

recovered at end of project life; consisting of:

Feedstock Inventory - one week's supply at cost;

Product Inventory - two weeks supply at

production costs, products, and by-products;

Accounts Receivable - one month's production

costs; Cash - one week's production costs less

depreciation; less Accounts Payable - one month's

supply raw materials at cost.

Debt repaid in unifonn series of annual payments

of principal and interest.

20 years

OPerating labor: $28,700/year

Foremen:$32,soo1year

SupervisOrs:$39,500/ year

45%operating labor plus supervision.

65% total operating and supervisory labor

including overhead.

$0.035/kWh.

$3.90/thousand pounds

SO.061thousand gallons

$1.251thousand gallons

$0.016/1b

$0.18/Ib

$0.10/Ib

SO.30/1b

$O.025/lb

$O.285/lb

SO.025/lb

123
-,.Q

l::::!

-fI.)

a

=e....

-

u

:s

'0

'0

cu

N....

-...

e

e

<

12

1.0

0.8

0.6

02

0.0

Results of Base Case Comparison

• 'Raw Materials Cost

• Amortized Production Cost

Kraft Organosolv

Anthraquinone Starting Material

Figure 5.2- Comparison of Costs; Base Cases for Anthraquinone Production

Table 5.4- Comparative Summary of Base Case Capital Investments (Millions of $)

Major Equipment Cost

Installation Costs

Piping

Instrumentation

Buildings/Structures

Auxiliaries

Outside lines

Engineering/Contingencies

Offsites

Total Fixed Investment

Working Capital

Total Utilized Investment

Or&anosolv

2.1

0.3

1.0

0.2

0.2

0.5

0.2

2.3

1.9

8.8

3.9

12.7

Kraft Black Liquor

2.1

0.3

1.0

0.2

0.2

0.5

0.2

2.3

1.9

8.8

1.9

10.7

Table s.s-Comparative Summary of Base Case Costs of Production ($nb of Product)

Raw Materials

Utilities

Operating Costs/Expenses

Production Cost

Capital Charges

Amortized Production Cost

Organosolv

0.592

0.028

0.097

0.718

0.098

0.816

124

Kraft Black Liquor

0.836

0.028

0.097

0.958

0.084

1.042 .
3.0

1.0

0.0

1) 9rganosolv lignin

2) Kraft lignin 3)S~e

4) Naphthalene

5) Benzene

6) Phthalic Anhydride

7) Anthracene

Comparison of Production Costs

of Anthraquinone -..0

-.,

(I)

Q

U

C

Q

.-., 2.0

"0

Q

c:

"tS

N

.-.,

...

Q

e

<

• Benzoyl benzoic IRingd~ANTHRAQUINONE .d closu

aa

1 2 3 4 5 6 7

starting material

Figure S.3-Amortized Production Costs of AQ from Different Starting Materials.

From Styrene

IDimerization I ...._--.. From Phthalic Anhydride

Phthalic

anhydride --iII.~IOxidation t • ANTHRAQUINONE

From Naphthalene/Butadiene

Naphthalene .. IOxidationI Naphthoquinone .. It:LtionI ANTHRAQUINONE

From Anthracene

Anthracene .. IOxidationl • ANTHRAQUINONE

From Benzene/Phthalic Anhydride

Benzene

Aluminum chloride

Phthalic anhydride

-- Friedel • Crafts

., alkylation

Benzoyl benzoic IRing 1 d~ANTHRAQUINONE acid c osu

Figure 5.4· Alternative Routes to Anthraquinone

125
'; ",

5.4.3Detailed Process Analysis- Phenolics from Biomass by Pyrolysis and Wood Phenolation

Pyrolysis of lignocellulosic feedstock has been demonstrated at NREL to be effective for producing a

number of different materials. Fast pyrolysis processes offer the advantage of high yields of Iiquid

products from different feedstocks (Bridgewater 1988; Soltes 1988; Hogan 1990; Overend 1985). In these

processes, pyrolysis temperatures are 4SOO-6OO"C, and residence times are on the order of seconds.

Solvolysis of wood is an alternative route to substituted phenolics. If carried out in a range of high

severities, at moderate temperatures, and long residence times, solvolysis yields reactive wood tars or

pastes, principally if phenol is used as a solvent. Lower severities give a phenol pulping process

(Lipinsky 1983), and at high severities, wood liquefaction occurs (Shiraishi 1986, 1987). These

processes both introduce phenols into the a- or B-position of the side chains of the phenylpropane units,

in addition to acid-eatalyzed ether cleavages at both a- and B-aryl ether linkages of the lignin units.

A more detailed process analysis of this process based on someof the published results, and alsoon some

more recent experimental findings ijohnson 1990), has been carried out. A definition of the process

chemistry in the literature was found to be sketchy. The following conditions were assumed: the plant

was sized to consume 1000 tons/day of wood feedstock. Wood phenolation is operated with a mixture of

20% of the low-molecular-weight phenolics recovered from the pyrolysis/fractionation process,

instead of the more expensive purchased phenol. The liquor-to-wood ratio is 5:1; water is found to be

necessary for the reaction to occur. The temperature is 25()0C for 120 min (600 psi steam). About 70%

soluble oils are obtained. The incorporation of phenolics is assumed at about 60%. An alternative

would have been to use the low-molecular-weight phenolics fraction distilled from the phenolation

process. This technology was then compared to producing phenols by fast pyrolysis.

The amortized production cost of this wood phenolation product is estimated at $O.25/lb (see Table 5.2).

This estimate is approximate because the published data do not contain sufficient detail for a more

complete technoeconomic assessment at this point. However, this production cost value, with an

uncertainty of about 40%, is close enough to that of the products derived from the fast pyrolysis and

fractionation above to indicate that the phenolation process is potentially competitive. The published

data on the reactivity and resin formulations suggest that the process has economic promise.

This analysis for the producing phenolics by fast pyrolysis indicates that waste sawdust can be

converted into phenol replacements at $0.10-SO.27/lb. In this evaluation, feed cost varied from $10-

$40/dry ton, plant life from 10-20 years, and return on investment from 15%-30%. The evaluation was

performed assuming a plant would use 1000 tons/day of feedstock, producing 140,000,000 lb/yr of

pyrolysis oils. This plant size corresponds to a relatively large resin production plant. The procedure

followed for the evaluation was described in section 5.4, and the process chemistry described in section

5.1.6. The results of the evaluation are shown in Tables 5.6 and 5.7.

Considering the range of phenol costs (SO.3-0.4/lb), depending on economic conditions and oil prices,

these results indicate that phenolics from these processes could be inexpensive substitutes for a portion

of phenol currently derived from petrochemicals. Smaller scale plants are possible but the amortized

production costs double. The process is attractive when wood feedstock is available at $40/ton.

5.4.4Detailed Process Analysis - Clean Fractionation of Lignocellulosics

NREL is developing a process to cleanly fractionate wood into its three major components: cellulose,

hemicellulose, and lignin for use in producing a number of chemicals evaluated in the raw materials cost

comparison. This summary describes the projected amortized production cost for the three components.

Since the patent protection is currently being filed for the process, fewer details can be revealed than in

other processes. The plant evaluated is projected to produce 660,000,000 lb/yr of cellulose; 256,200,000

lb/yr of hemicellulose (as xylose) and 332,700,000 lb/yr of lignin. The process chemistry is shown in

block form in section 5.3.2. A summary of the amortized production costs is given in Tables 5.8 and 5.9.

126
Table 5.6 - Summary of Base Case Capital Investments (Millions of $)

Major Equipment Cost 7.4

Installation Costs 1.1

Piping 3.3

Instrumentation 0.8

Building and Structures 0.8

Auxiliaries 1.8

Outside tines 0.8

Total Direct Cost 16.0

Engineering/Contingencies 7.9

Offsites 6.6

Total Fixed Investment 30.5

". Working Capital 3.5 :':

Total Utilized Investment 34.0

Table 5.7 - Summary ofBase CaseCosts of Production (snb of Product)

Raw Materials (wood waste @ $40/ton)

Utilities

Operating Costs/Expenses

Production Cost

Capital Charges

Amortized Production Cost

0.094

0.007

0.027

0.128

0.037

0.165

Table 5.8 - Summary of Base CaseCapitallnvestments(Millions of $)

Costs Inside Battery Limits

Offsites

Total Fixed Investment

Working Capital

Total Utilized Investment

37.3

11.2

48.5

6.1

54.6

Table 5.9 - Summary of Base Case Costs of Production (snb of Product)

Raw Materials

Utilities

Operating Costs/Expenses

Production Cost

Capital Charges

Amortized Production Cost

127

0.032

0.014

0.004

0.05

0.006

0.056
. ' , ':,'. "';:

5.4.5Detailed Process Analysis - Acetylated Wood

Acetylation of wood imparts added chemical and biological resistance to wood fibers. Products made

from acetylated wood show:

1) high dimensional stability both in the thickness and lineal directions

2) a high level of rot resistance

3) a low degree of thermal expansion

4) smooth surfaces that do not require further sanding

5) a uniform density throughout the product wall

6) no increase in toxicity of the wood

7) high strength-both wet and dry

8) a high degree of UV radiation stability

9) no change in flammability.

Acetylated veneers can be pressed along with the acetylated fiber mat to yield veneer-faced fiberbacked products <Rowell, in Chum 1989).

A more detailed assessment of the acetylation of wood process was made using the methodology

described for anthraquinone. The financial results of the study are summarized in Tables 5.10 and 5.11

that present the estimated capital and processing costs for each of the three general classes of

feedstoeles.The plant evaluated was projected to produce 500,000,000 lb/yr of acetylated wood. The

evaluation considered treating three different materials: wood particles, fibers, and veneers. Note

that a byproduct credit can be taken for the acetic acid produced. The process based on particles has the

lowest fixed investment, about 50% of the level required for processing fibers. Particles processing is

simpler in the solids-handling operations and requires less specialized equipment.

Processing costs are dominated by the net cost of the acetic anhydride raw material, that corresponds to

the total acetic anhydride cost minus the acetic acid by-product cost (14.4 - 5.5 = 8.9 cents per pound of

the product), that is assumed to be the same for these feedstocks. This element of cost is %% in the case

of fibers. The latter case is higher-cost principally because it requires more operators in the morecomplex solids-handling systems, with their expensive equipment. In both cases, acetic anhydride was

assumed to be purchased at $0.22 per pound and acetic acid was credited at $0.10per pound. The process

description is given in section 5.3.6, and the results of the evaluation are given in Tables 5.10 and 5.11.

Table 5.10- Comparative Summary of Base Case Capital Investments (Millions of $)

Particles Fibers Veneers

MajorEquipment Cost 3.8 7.7 8.2

Installation Costs 0.6 1.1 1.0

Piping 1.7 3.4 2.9

Instrumentation 0.4 0.8 0.6

Buildings/Structures 0.4 0.8 0.6

Auxiliaries 0.9 1.9 1.6

Outside Lines 0.6 1.1 1.0

Engineering/Contingencies 4.2 8.4 7.9

Offsites 3.5 7.0 6.6

Total Fixed Investment 15.9 32.3 30.3

Working Capital 14.1 14.1 14.1

Total Utilized Investment 30.0 46.4 44.4

128
Table 5.11· Comparative Summary of Base Case Costs of Production ($lib of Product)

Particles Fibers Veneers

Raw Materials 0.14 0.14 0.14

Utilities 0.0 0.009 0.008

Operating Costs/Expenses 0.004 O.OOS 0.009

Byproduct Credits (0.055) (0.055) (0.055)

Production Cost 0.093 0.106 0.106

Taxes/Depreciation 0.004 0.005 0.005

Amortized Production Cost 0.097 0.111 0.111

5.4.6 Detailed Process Analysis - Starch Plastics

Starch acetate and a maleic anhydride/styrene copolymer can be extruded to give a new biodegradable

material. Since portions of this work are proprietary, some details cannot be revealed in this

evaluation. Three base cases were evaluated in this study to give a comparison of the projected

amortized production costs. The plant was projected to produce 10,000,000 Ib/yr of graft copolymers.

The results of the evaluation are shown in Tables 5.12 and 5.13.

Table 5.12- Comparative Summary of Base Case Capital Investments (Millions of $)

Cost Inside Battery Limits

Offsites

Total Fixed Investment

.Base Case 1

14.3

2.9

17.2

Base Case 2

4.8

2.9

7.7

Base Case 3

2.3

0.5

2.8

Table 5.13- Comparative Summary ofBase Case Costs of Production ($lib of Product)

Base Case 1 Base Case 2 Base Case 3

Raw Materials 0.62 0.62 0.71

Utilities 0.38 0.04 0.004

Operating Costs/Expenses 0.25 0.13 0.08

Production Cost 1.25 0.78 0.79

Taxes/Depreciation 0.22 0.13 0.04

Amortized Production Cost 1.47 0.91 0.83

129
6.0BIOPROCESSING ROUTES TO CHEMICALS AND MATERIALS

6.1 Introduction and Rationale

Harnessing the activities of microorganisms has been one of humanity's greatest scientific and

technical achievements. Microbial fennentations have been used for millennia to enhance food

products (consider bread, wine, and cheese) and early in this century, microbial fennentations were a

major source of commodity chemicals and fuels such as butanol and acetone. Increases in the cost of

biological feedstocks and the evolution of the petrochemical industry after World War Il rendered

these latter processes economically uncompetitive (lones and Woods 1986).

In the past decade, researchers have made many technological advances that promise, in concert, to

significantly improve the economic competitiveness of biobased processes. Evaluation of this window

of opportunity focuses on the inherent attributes of biological processes, the application of new

technology to overcome past limitations, and integration with nonbiological process steps.

Fermentation processes involve chemical reactions carried out by living microorganisms that convert

certain organic compounds to other compounds. The process mayor may not occur in the presence of air.

Microorganisms also produce enzymes that can themselves serve as catalysts for chemical reactions. A

common characteristic of fennentation and of most biological processes is that the end product of the

processis in dilute aqueoussolution.

Bioproeesses include fennentations and biotransfonnations. In fermentations, a population of microbes

converts a feedstock (e.g., a simple sugar) into an end product through a series of reactions known as a

metabolic pathway. Biotransfonnations are processes in which a compound is converted into a

structurally related product in one or a small number of reactions. The biotransformations can be carried

out with growing or nongrowing cells, or by cell-freeenzyme systems.

Fermentations and biotransformations have a number of beneficial attributes. Cells and enzymes can

carry out most of the central classes of reactions used in the chemical industry (e.g., hydroxylations,

condensations, oxidations, esterifications, acylations, and halogenations), and they do so with much

greater specificity. Biobased processes often yield a single product, and in general, give much simpler

product mixtures than thermochemical processes. Other advantages of fermentations and

biotransformations, compared to thermochemical processes, include:

• Mild reaction conditions that permit converting substances labile to the extremes of heat,

pressure, and chemical conditions inherent to thermal processes and that allow less expensive

materials to be used in reactors

• Reactions at positions in molecules that are not ordinarily reactive, or at positions not favored by

thermal processes

• Coupling long sequential series of specific chemical reactions by a microorganism containing

several enzymes (a metabolic pathway)

• Producing fewer toxic byproducts than many thermal reactions, thereby greatly reducing the

environmental cost of a given conversion.

Until recently, however, the economic competitiveness of biobased processes for the producing low- or

moderate-value chemicals has been limited by a number of technical obstacles. Bioprocesses tend to

yield dilute aqueous solutions of product, and it is often the cost of product purification that prevents

commercialization. In other cases, product yield, the feedstock cost, or an insufficient reaction rate

create barriers to commercialization. A series of technological advances, summarized in section 6.3,

131
should allow research and development to overcome these obstacles, making biobased production of

chemicals economically attractive.

The establishment of a biobased processing industry for making chemicals from renewable feedstocks

will enhance the chemical industry. In addition, biobased and thermal processes can be tailored to

produce chemicals that themselves serve as intermediate-volume feedstocks for the existing

petrochemicals industry.

As part of the Alternative Feedstocks program effort to integrate biobased and thennal processes, we

will give attention to a new and developing class of catalysts - biomimetic catalysts. Biomimetic

catalysts stand at the interface between biobased and thermal processes. These catalysts, which are

only now beginning to be developed, are nonenzyme catalysts that carry out reactions using mechanisms

discerned for enzymatic reactions. They tend to retain the attributes of biobased conversions (listed

above) and they also offer greater stability and flexibility. Evaluating the evolution of this class of

catalyst will be monitored and developments will be incorporated into the analysis of longer term

opportunities.

6.2 Target Products and Markets for Chemicals

Currently, on the order of 5.0 quads of fossil fuel are used annually to produce chemicals. Of this,

approximately 3.9 quads are derived from petroleum. Of the vast number of chemicals produced by

this industry, approximately 90% can, in principle, be produced from renewable biomass feedstocks

(Busche 1989). The Alternative Feedstocks program will attempt to define the most economical

chemical candidates that might be produced from biomass in order to provide feedstock flexibility to

the chemical industry and to accrue the multiple benefits to the United States economy of energy

security, economic growth, and environmental stewardship.

6.2.1 Direct Substitution for Existing Chemicals

Two classes of products can be made from renewable feedstocks. The first class includes existing

commodity chemicals not currently produced from biomass. Examples include acetaldehyde, acetic

acid, acetone, n-butanol, glycerol, and isopropanol. Such products have an advantage in that the

market is already established and thus they require less effort to sell. On the other hand, competition

will be strictly on the basis of price because no product perfonnance advantages are possible for products

derived through biotechnology over those produced from petroleum. Because established products are

manufactured in plants for which the capital investment is all or partially paid off, economics often

favor the incremental expansion of existing petrochemical-based facilities. In this area, we have

attempted to define processes or pathways that can yield a family of products rather than a single

chemical.

6.2.2 Development of New Chemicals, Materials, and Feedstocks

The second class of products is new materials that can be derived through biotechnology. These are

products that are unique to bioprocessing. Examples include new adhesives, biodegradable plastics,

biocompatible solvents, degradable surfactants, and enzymes for various applications. New materials

can also lead to an increased demand for existing chemicals such as the anticipated demand for lactic

polymers based on lactic acid. For such products, competition would probably be based on performance,

and the advantages of the bioproducts might provide unique niches for initial introduction into the

marketplace. Therefore, less price pressure is possible initially for such new products. However, to

have a substantial impact on petroleum consumption, large markets must eventually develop. An

alternative way to open markets for biobased chemicals is to establish new uses for biobased products as

feedstocks for producing high-volume chemicals. Thus we have sought to identify biobased processes

that can be integrated with thermal processes to produce a spectrum of chemicals.

132
We began the study with 40 promising chemicals and materials identified by initial screening that can

be produced from renewable feedstocks through bioprocessing. Next, we identified key process areas

applicable to a multiplicity of promising products. This strategy was designed to promote developing a

directed technology base that is balanced, with a portfolio of key processes and product families with

representative target products. Since it is always desirable to build on the existing technological base,

a thorough review of public and private sector data was initiated. A more synergistic database of

infonnation is needed for a less fragmented approach to this new industrial opportunity, allowing more

in-depth comparisons with other chemical process investment opportunities by industry. This

evaluation will enable the Alternative Feedstocks Program to take advantage of the existing cadre of

experts, thereby avoiding duplicating analysis and promoting a synergistic infonnation base.

6.3Opportunities for Technology Improvement

Large quantities of alcohol fuels, some organic acids, and amino acids are currently produced by

biological systems; nevertheless, most of the other potential bioprocessing routes are not being

exploited because of poor economic performance that results from inefficient metabolic pathways, low

yields, unacceptable or unknown kinetics, or inefficient processing techniques. In the past decade,

researchers have made tremendous advances in techniques for improving both biocatalysts and

processing systems. Increased metabolic understanding and new genetic manipulation techniques offer

the likelihood that the intrinsic metabolism of a microbe may be altered to improve its product Yield,

bioconversion rates, and product tolerance. There is strong evidence that significant improvements can

be made by developing and using technology that takes advantage of advanced processing concepts. For

example, a common bioprocessing issue is that most products are fonned only in dilute aqueous solution

because of the autoinhibitory nature of the desired product. It is now possible to remove the inhibitory

product from the ongoing fermentation as well as to develop a microbe that is able to tolerate higher

product concentrations. Areas where advanced technology could have an important impact are outlined

and the requirements for innovative RD&Dare defined below.

A focused research and development effort is needed to improve both the process and the microbial

metabolism. Six primary criteria will be used to evaluate possible advanced bioprocessing concepts and

the potential of metabolic pathways modifications. Each of the possible innovations will be

considered on the basis of

•

•

•

•

•

•

volumetric productivity,

yield as a fraction of theoretical Yield,

the product quality in purity and concentration,

the energy use inherent in the process,

the potential environmental impact, and

the operability.

All of these criteria are considered to be important, but productivity and Yield are of particular interest

because these parameters have the most direct bearing on economic viability. We can estimate the

maximum improvement in yield from the theoretical stoichiometry to determine the potential

maximum impact from a program in that area. For example, Lactobacillus already produces lactic acid

from glucose at near 1 g lactic acid/g glucose, the stoichiometric limit; thus, further yield improvements

are unlikely to have an impact. On the other hand, butanol is produced by Clostridium acetobutylicum

with a maximum yield of less than 0.3 g/g with significant amounts of coproducts; thus, metabolic

improvements might increase the yield by more than 50%. Similar assessments can be made for other

proposed process and metabolic improvements. These potentials will be evaluated in a process economic

model for a base-case technology to determine if the potential for improvement is sufficient to alter the

economics and create a new opportunity.

133
6.3.1New Technologies in Genetic and Metabolic Engineering

Metabolic engineering is the deliberate alteration of an organism's metabolism, the chemical steps by

which it converts feedstocks to products, through genetic manipulations. In the case of bioprocessing for

producing chemicals, the objective of this engineering would be to improve the aspects of microbial

physiology that tend to limit the commercial viability of bioprocesses:

• Poor tolerance to high concentrations of the desired product

• Production of byproducts

• Moderate or low conversion rates

• Requirements for expensive nutrients

• Instability of the microbial culture

• Need to utilize additional renewable feedstocks.

The relevance and importance of these items vary for each process considered, and depends on the

organism involved, its metabolism, and the targeted compound.

The potential to channel material into desired products is illustrated schematically in Figure 6.1. The

most straightforward types of alterations possible are removing competitive pathways that divert

material from the desired product and enhancing the activity of a rate-limiting enzyme. Indirect

effects that can affect energy use or product tolerance can also significantly improve product yield. In

addition, novel technology developments enable one to alter the specificity of enzymes to create

biological catalysts that give new products distinct from those originally produced. Research has

demonstrated the potential of these approaches for improving bioprocessing. Examples of metabolic

engineering include the introduction into E. coli of the ability to produce primarily ethanol, normally a

minor product (Roy 1992), and addition of a multistep pathway for colorant production into brewer's

yeast (Ausich et al. 1992). Examples of enzyme engineering include alterations of the enzyme that

produces lactic acid to give new enzymes that produce malic acid or various derivatives of lactic acid

(Wilks et al. 1992). Genetic manipulations can be 'dtrected to altering product distribution, improving

productivity and product quality, minimizing energy use and environmental impact, or improving the

operability of the overall process.

Metabolic Engineering can alter the activity or regulation of enzymes.

Examples: Enzyme 1 is the rate-limiting step of a pathway; increase its production or activity

Enzyme 2 gives the undesired side product C; eliminate its production or activity

Enzyme 3 generates the desired product D; enhance its production or activity

Figure 6.1- Metabolic Engineering

Results such as these have occurred largely because of new or recently improved genetic technologies,

These advances greatly enhance our ability to manipulate the metabolism of various organisms and

include the following:

134
•

, ."1

• PCR (the polymerase chain reaction). This technique generates large quantities of a gene and .

can simultaneously introduce precise changes in the gene's DNA sequence. The changes

introduced can be designed to alter the activity, stability, or regulation of the activity of the

protein produced by the gene. .

• Physical methods for DNA introduction. One new method, electroporation, uses cells

temporarily permeable to DNA outside the cell. Another new approach literally shoots small

particles coated with DNA into cells, circumventing the need to develop specific biological

methods.

Technologies for control of genes. Introduction of DNA antagonistic to a cell's DNA, called

antisense DNA, causes malfunction of the specific gene targeted. This method permits

alteration of the regulation or activity of native genes, thereby affecting metabolism.

To date, the full potential of these methods has not been applied to metabolic engineering for the

production of industrial chemicals. Manipulations of metabolic pathways and of individual enzymes

that were not reasonable to attempt a few years ago are now realistic possibilities.

6.3.Ll Future Technological Advances

The advances described above create immediate, specific opportunities for improving the economics of

producing chemicals from renewable feedstocks. Additional technological developments can be

anticipated that should affect these processes significantly, and these areas of technology provide

targets for mid- and long-term research activities.

•

•

Microbiology and metabolic engineering. Low product tolerance is recognized within

the biotechnology industry as a major barrier to favorable process economics. Organisms

tolerant of extreme concentrations of products or of low pH.should be investigated as

potential agents for biomass processing. New organisms, genetic systems for tolerant

organisms, and directed selection for increased tolerance could provide valuable

improvements. Metabolic pathways should be engineered into more tolerant organisms.

Bioprocessing materials. Near-term efforts exploit new .materials originally

developed for applications other than bioprocessing. Materials science research into

the discovery of novel membranes, ceramics, adsorbents, and reactors can be expected to

provide new technologies that can be adapted for use in bioprocessing.

• Protein engineering. Future advances in understanding protein structure and function

relationships, derived in part from analyzing the effects of structural changes

introduced by genetic engineering, promise to allow the predictable alteration of a

protein's properties to generate enzymes with enhanced capabilities for bioprocessing,

such as increased stability, tolerance of organic solvents, or novel catalytic activity.

• Biomimetic catalysis. Biomimetic catalysts attempt to mimic the active site of

enzymes in low molecular weight, synthetic catalysts to unite the favorable properties

of enzymes (efficiency, specificity, and selectivity) with the small size, stability, and

low cost of synthetic catalysts. This research could produce a new generation of

catalysts for converting biomass or biomass-derived products to industrial chemicals.

Ideally, mid- and long-term research priorities should evolve in parallel with near-term activities

that seek to commercialize existing technology, rather than as isolated efforts. Coordinating these

activities will ensure that the technology areas addressed truly have potential to overcome the

barriers which still exist to producing chemicals from renewable resources. Systems analysis and input

from industrial advisors should be used to help set research priorities.

135
Page 136 is missing from all existing copies of this report. 
must be produced and then introduced and maintained with high activity within the bioconversion

reactor. Conventionally, this requires aseptic conditions with steam sterilization of all inlet streams.

Improvements that decrease or eliminate the need for strict sterility will decrease both capital and

operating costs; these improvements could include the use of extremophiles (microbes working at low

pH or high temperature), high-product-tolerant microbes, or the selective retention of the desired

microbes by immobilization. The stirred tank batch reactor is the conventional technology for

bioconversion. Large increases (5 x to 500 x) in volumetric productivity are achievable by adding cell

retention of some fonn in a continuous operation. Cell retention (either recycle or immobilization) will

be a key in reaching the largest improvements and must be investigated for the particular system. The

issues of mass and heat transfer must be addressed for the large scale operation of these technologies.

Bioconversion steps are generally inhibited by the desired product. This introduces the broad strength

of combined processes. SSF combines enzymatic hydrolysis and fermentation to decrease inhibition

caused by the intermediates. Several other processes have been proposed for simultaneous fermentation

and separation. The separation can be accomplished by adsorption, extraction, membrane-based

processes, or precipitation. Adsorption and precipitation are particularly relevant to producing organic

acids such as succinic acid. With adsorption, more than 4-fold rate increases are possible; equivalent

increases have been observed with precipitation. A completely different long-term approach involves

using biocatalystsin nonaqueous systems such as organic solvents, biphasic liquids, or supercritical CO:z.

Downstream processing encompasses separation, purification, and waste use. Separating the desired

product from these dilute, generally aqueous solutions is frequently the second most costly part of the

process (raw material cost is often first) and is usually the largest energy consumer. Conventional

separation technology for most bioproducts is either distillation (with high energy costs) or

precipitation (with large amounts of waste salts produced). Replacing these separation methods is a

critical area deserving near-, mid- and long-term programs. Adsorption, Iiquid-hquid extraction,

pervaporation, and other membrane processes such as electrodialysis are the most promising

alternatives. Adsorption should be investigated as a near- to mid-term replacement for precipitation

of organic acids. Electrodialysis with bipolar membranes may be effective in recovering organic acids.

Extraction and pervaporation have advantages for producing neutral solvents or volatiles.

In the near tenn, conventional waste treabnent technologies are adequate; however, they must be robust

and forgiving of a variety of streams and transients. The long-term emphasis must be on approaching a

dosed system through waste use, reuse, minimization or recycle. In the broadest sense, the total product

and process life cycle needs to be considered. In particular, the proposed processes should not generate

any hazardous waste. Bioconversions also produce large volumes of dilute streams with surplus

nutrients. The biocatalysts should be studied to minimize or reduce their fee requirements. These

technologies have enormous potential in overcoming the barriers to commercialization. Development

and demonstration of improved technology will be critical for this program.

6.4 ProductlProcess Selection

A wide variety of chemicals and materials can be produced through fermentations and bioconversions.

These products could be classified into the following groups:

• Amino Acids

• Antibiotics

• Biopolymers • Enzymes

• Nucleic-acid-related compounds

• Organic acids

• Steroid hormones

• Foods and alcoholic beverages

• Miscellaneous organic chemicals

137
A set of criteria was defined to select, from the thousands of potential candidates, those candidates

that would be evaluated in the initial development of a product portfolio. These criteria were

developed to be consistent with the overall goal of the program. No single criterion was the most

important for selecting candidates into the portfolio. Additional candidates will be added to the

portfolio on a regular basis. The aiteria for selecting additional candidates may be the same as for the

original selection and will continue to be impacted by industrial interest.

The original set of selection criteria is as follows:

• High theoretical product yields from substrate

• Market interest in the product as an end product or as an industrial-important

intermediate

• High production volume (current or potential)

• Nonfood use

• Ability to be biologically synthesized from the common sugars derived from various

fonns of biomass.

Given the scope of candidates in the portfolio, a methodology was devised to rank the candidates into

near-, mid-, and long-term opportunities. The time scale for these opportunities is defined as 0-5years,

5-10 years, and 10 or more years, respectively.

The ranking methodology consists of three stages. The first stage, referred to as the initial product

screening, evaluates products using very approximate economic analysis based only on the prices of the

products, byproducts, and starting materials.

The second stage of the analysis compares, where possible, the proposed bioprocess route to the current

conventional petrochemical route. This again is a very approximate analysis that compares only the

raw material costs for each process. The methodology used is similar to that used for products from

thermal/chemical routes, described in section 4.2.1.

The third stage of the analysis, referred to as the integrated product/process screening, takes into

account more specific process economic characteristics needed to estimate production costs and return on

investment to predict the selling price of the product. The difference between the predicted selling

price and the current or projected market value, together with the set of technical and economic

assumptions used in the analysis, is used to classify the products into one of the three portfolio

categories, near-, mid-, and long-term opportunities. Figure 6.2 illustrates the overall selection and

ranking scheme used. This strategy will allow development of a concurrent research and development

approach involving basic research, enabling technology (bridging research), and applied precommercial development.

6.4.1Initial Product Screening Methodology

Many diverse products could be produced by biological routes from renewable feedstocks such as starch

crops (e.g., com) and lignocellulosic biomass (e.g., grasses and wood). However, not all these products

can be produced in sufficient yields to be economically viable. The merits of each product can be

estimated simply by determining the quantity and cost of feedstock required to generate a given amount

and value of product. If the revenue generated from the sale of the products is insufficient to cover the

cost of the substrate, a lower cost feedstock or one with a more favorable composition must be devised.

The purpose of the initial product screening is to rank the candidates based on a simple economic

criterion, the fraction of revenue for feedstock (FRF); i.e., the ratio of the cost of the feedstock to the

value of the products derived from the feedstock. The FRF can be calculated for each of the candidates

using a number of different feedstocks. The FRFvalues can be determined for established experimental

yields and theoretical maximum yields to determine the merits of the products now and their maximum

138
-j

Selection Criteria

Feedstock &

Product Costs,

Yields

Technical &

Economic

Assumptions

Annual PortfolioAssessment

1

Near-term.

Opportunities

Potential

Chemicals &

Materials

First and

Second

Stage

Screening

Analysis

Third

Stage

Screening

Analysis

Mid-tenn

Opportunities

\

)~

Qualitative

Influences:

EnergyImpacts,

Enviromnental

Quality,

Economic

Competitiveness,

Probabilityof

Success

1

Long-term

Opportunities

v

End-Use

Programs

-ISD

- Industry

v

Enabling

Technologies

-AICD

- Industry

Basic

Research

-OER

-NSF

Figure 6.2 - Screening and Ranking Methodology

139
future potential based on this simple methodology. Because such an analysis does not consider other

factors such as the cost of product recovery, it should be viewed as a first step to rapidly identify

products that show limited promise based on stoichiometry alone. The results of the FRFanalysis are

given in section 7.0.

6.4.L1 Fraction ofRevenue for Feedstock

Calculating the FRF requires knowing the cost and composition of the feedstock, the yield of the

product and any byproducts, and the market values of the products and byproducts. The FRF is

calculated using equation (1).

F . ofR r __..J_ k ICost of Feedstock ) raction eoenue JOT Feedstoc = ValueofProducts

where i = Component i of the feedstock

Cf = Unit cost of the feedstock, dry weight

a;. = Fraction of maximum theoretical yield of product derived from

componenti

Yi = Theoretical yield of product derived from component i

Vi = Value of the product derived from component i

Xi. = Fraction of component i in the feedstock

= Hydrolysis weight gain conversion factor (if applicable, section 6.4.1.2)

Note that the FRFmust be less than unity for a process to be economically feasible; i.e., the value of the

products must be greater than the cost of the feedstock. The lower the FRF, the more promising the

process looks for further investigation.

6.4.1.2 Feedstocks Evaluated

Three feedstocks were evaluated: glucose syrup, corn, and hybrid poplar. The prices used for each of

these feedstocks are given in Table 6.1. The price of glucose syrup was obtained from a large corn wetmilling company. The price for corn was obtained from the USDA's Market News Service. The price for

hybrid poplar is from the US. DOE Biofuels and MUnicipal Waste Technology Multiyear Plan

(unpublished).

Glucose syrup is directly fermentable. Com and hybrid poplar will yield glucose upon pretreatment and

hydrolysis; they yield other byproducts as well whose values are known or can be estimated (section

6.4.1.5).

Table 6.1 - Feedstocks Evaluated and Current Prices

Feedstock

Glucose Syrup (99 DE)

Com

Hybrid Poplar

Price($/lb)

0.102

0.052

0.021

Glucose syrup, com, and hybrid poplar were chosen as representatives of the types of feedstocks that

could be used in near-, mid-, and long-term opportunities. Com as a feedstock can be further

differentiated by the method used to convert its starch fraction into glucose. Both the wet-milling and

dry-milling process were considered. These processes yield a substantial fraction of starch as a

percentage of the starting material, however, the byproducts are quite different. Thewet-rni11ing

fractionation process produces a starch slurry, crude com oil, com steep liquor, corn gluten meal, and com

gluten feed. The starch slurry can be hydrolyzed to glucose by chemical, enzymatic, or chemical and

140
enzymatic hydrolysis processes. The com-to-ethanol dry-milling process produces a stillage called

distillers dried grain and solubles (DOGS) and carbon dioxide. The DOGS is sold as an animal feed;

the carbon dioxide is not usually recovered. The byproducts from the dry-milling process could be

different from those resulting from ethanol production if a different product is produced in the

fennentation. For example, the fermentation stillage may have no value as an animal feed if the

organism used to produce the chemical of interest is E. coli. In this case, a protein extraction process

might be required to recover a salable byproduct. Similarly, an aerobic fermentation would produce

little, if any, carbon dioxide. When performing the FRF calculations using dry-milled com as the

feedstock, DOGS and carbon dioxide are assumed to be the only byproduets produced. The current

market value of DOGS is taken as its byproduct credit; no credit is taken for the carbon dioxide.

For the FRF analysis, each feedstock is arbitrarily assumed to include up to six constituents, including

cellulose, hemicellulose, starch, and possibly three other components. The compositions of the

feedstocks evaluated are given in Table 6.2.

Table 6.2- Feedstock Compositions

GlucoseSymp Wet-Milled Com

Constituent

Cellulose

Hemicellulose

Starch

Glucose

Other Sugars

Wt %

0.00

0.00

0.00

97.50

2.50

Constituent

Cellulose

Hemicellulose

Starch

Com Oil

Gluten Feed

Gluten Meal

Wt %

0.00

0.00

67.62

3.70

24.47

4.21

Dry-Milled Com

Constituent Wt %

Cellulose 0.00

Hemicellulose 0.00

Starch 71.85

DOGS 28.15

Hybrid Poplar

Constituent Wt %

Cellulose 48.64

Hemicellulose 16.84

Starch 0.00

Lignin 24.25

Extractives 5.49

Ash, Proteins 4.78

Com and hybrid poplar have starch or cellulose as major constituents. Cellulose and starch are

polymers of glucose units, which upon hydrolysis yield the glucose monomer (equation 2).

[2]

..

Depolymerizing the polymer to n monomeric units requires the addition of n water molecules. The

molecular weight of the polymeric unit is 162, while the molecular weight of glucose is 180. The

percentage weight increase upon hydrolysis is 180/162 =111.1%. This correction factor is applied to the

cellulose and starch mass fractions to account for the weight gain when the polymer is hydrolyzed to

glucose.

Similarly, hemicellulose can, as an approximation, be described as a polymer of xylose units (mol wt = 132), which upon hydrolysis become xylose or related five-carbon sugars (mol wt = 150). The weight

gain upon hydrolysis in this case is 150/132 =113.6%. The hemicellulose mass fraction is multiplied by

this correction factor to get the xylose mass fraction available for conversion. For this analysis, the

hemicellulose fraction of the feedstock is assumed to be completely hydrolyzed to xylose and

subsequently converted to ethanol (Section 6.4.13).

6.4.1.3 Byproduds

As much revenue as possible should be derived from the feedstock for any process to be economically

viable. Therefore, it is important to consider converting the other fractions of the feedstocks listed in

Table 6.3 into useful byproducts. In the com wet milling process, the com oil is extracted early for sale

as food and the protein is recovered prior to processing the starch for sale as animal feed coproducts

(called com gluten meal and com gluten feed). For dry milling of com, the solid residue left after

conversion of the starch into products is dried for sale as DOGS, an animal feed coproduct. For

lignocellulosic biomass, the xylose derived from the hemicellulose is assumed to be converted into

141
ethanol while the lignin is burned as boiler fuel. The yield factor used in the calculations is the

theoretical conversion of xylose to ethanol (0.511 lb ethanollib xylose). Table 6.3 summarizes the

values of the coproducts,

Cgproduct

lignin - Boiler Fuel

Crude Com Oil"

Gluten Feed'"

Gluten Meal··

DOGS··

Ethanol

Extractives

Ash, Protein

Table 6.3 - Feedstock CoproductValues

COJ!Toduct Value (S!lb)

0.020

0.132

0.053

0.150

0.058

0.091

0.000

0.000

• . '

Chemical Marketing Reporter, December 20, 1991

... Alcohol Week's New Fuels Report, November 11, 1991

Processes resulting in coproducts with higher values would be desirable. This analysis considers only

coproducts that are currently being produced eConomically; thus, this stage of the analysis could be

viewed as a worst-case scenario. Future analyses will consider other value-added co-products.

Significant economic benefit would be achieved if the lignin fraction of lignocellulosic biomass could be

converted economically to useful higher-value products, rather than used as boiler fuel. This

conversion most likely would be by thermal or chemical methods.

6.4.1.4 Experimental Yields

The literature was thoroughly searched to find current values for product yields. The experimental

yields selected from the literature are based on glucose as the substrate. In most cases, the literature

does not specify whether the yield was based on substrate consumed or substrate fed. The assumption is

that the unit for the experimental yield is mass of product formed per unit mass of substrate consumed.

6.4.1.5 Theoretical Yields

The maximum theoretical yield of product on substrate, Yp/St (carbon equivalents of product formed per

carbon equivalent of substrate consumed), is the minimum of the three yields discussed below (Andrews

1989). These yields are defined as the maximum yield that could be obtained if all the substrate were

used to make a single product.

• Yc: Yield based on carbon availability

• YH: Yield based on reducing potential

• YE: Yield based on energy availability

The stoichiometric coefficient for product formation written in terms of carbon equivalents provides Yc -

As an example, the stoichiometric equation, written in terms of carbon equivalents, for the biosynthesis

of ethanol from glucose can be written as shown in equation 3.

[3J

One carbon equivalent of glucose produces 0.667 carbon equivalents of ethanol and 0.333 carbon

equivalents of carbon dioxide. Thus, Yc=0.667.

142
The yield of product based on available reducing power, YH, is defined as the ratio of the generalized

degree of reduction of the substrate to the generalized degree of reduction of the product. The

generalized degree of reduction of a compound can be thought of as the number of available electrons per

carbon equivalent (equation 4).

[4]

The generalized degree of reduction of any compound, represented by the chemical formula CHaOt,Nc is

calculated using equation 5.

1=4 + a - 2b -3c [5]

Returning to the ethanol-from-glucose example, the generalized degree of reduction of glucose (Gi2D)

is shown in equation 6.

15 = 4 + 2 - (2) 1 = 4 [6]

The generalized degree of reduction of ethanol (CH300.S) is given in equation 7.

1p=4 + 3 - (2) 0.5 =6 [7]

Thus, the maximum yield of ethanol from glucose based on available reducing power, VH, is 4/6 = 0.667,

the same value as Yc determined from the product formation reaction stoichiometry.

Calculation of the yield based on energy availability, YE, requires knowledge of the metabolic

pathway used by a particular organism to synthesize the product from the substrate. Specifically, one

needs to know:

• The amount of ATP generated during the catabolic breakdown reaction, per carbon

equivalent of substrate, by substrate level and oxidative phosphorylation

• The amount of ATP generated per carbon equivalent of substrate by substrate level

phosphorylation before the product fonnation pathway diverges from the catabolic

pathway

• The amount of AlP required per carbon equivalent of substrate to synthesize the product

from the precursors diverted from the catabolic pathway.

For products fonned anaerobically, YE> Yc and energy limitation is impossible. Also, simple products

fonned aerobically are either carbon- or reduction-limited; energy limitation is impossible because the

product SYnthesis requires no additional ATP beyond that generated from the catabolic breakdown

reactions. Values for YE are not calculated because of the complexity involved in the determination and

because the synthesis ofmost products would not be energy limited.

The minimum value of Yc and YH is used as the maximum theoretical Yield, YpIs, on a carbonequivalent basis. Because all product and feedstock price information is on a weight basis, the desired

unit for the Yield factor is mass of product fonned Per mass of substrate consumed. The transfonnation of

143
the yield unit is achieved by multiplying YpJs by the weight fraction of carbon in the substrate, then

dividing by the weight fraction of carbon in the product (equation 8).

Y _( c - equivalent product] pis - c-equioalent substrate

6.4.L6 Product Values

[

substrate wt % carbon]

product wt % carbon = amount of productamountofsubstrate [8]

... .'.

The current prices of the product candidates were obtained from the Chemical Marketing Reporter

(CMR),November 4, 1991;these are given in section 7.0, Table 7.1. For chemicals not listed in the CMR,

the prices were obtained directly from a manufacturer or from the SIGMA Chemical Company 1991

catalog.

Prices from the SIGMA catalog were adjusted using a factor determined as follows. Prices for six

chemicals listed in the CMR also were obtained from the SIGMA catalog. The ratio of the CMR price

to the SIGMA price was calculated for each of the six chemicals. The average of these ratios, RSIGMA!

was used to adjust the prices of the chemicals given by the SIGMA catalog. The value of RSIGMA was

0.11.

For some candidates the corrected RSIGMA price still was too high for a commodity chemical or even a

large-volume specialty chemical. For example, the price information of polyhydroxybutyric add was

given in the SIGMA catalog as $2,812/lb. The RSIGMA corrected price is still $312/lb. For this

compound to compete as an intermediate for the production of biodegradable plastics, its price would

have to be in the vicinity of $O.50/lb. Therefore, the price of polyhydroxybutyric add was arbitrarily

set at $O.50/lb for this analysis. This arbitrary valuation was exercised for a number of the candidates

whose current prices seemed too high for estimates of their future market value.

6.4.L7 Summary

The objective of the initial product screening stage was to provide a simplified quantitative assessment

of the economic feasibility of a project. This assessment can be used together with qualitative input to

rank the order of more detailed analyses of the projects under consideration. The methodology

developed is iterative in nature. Demonstrated yields for various candidates will undoubtedly

improve and estimates of the costs of dedicated feedstocks and market values of the candidates will be

periodically revised. These changes will necessitate a periodic review of the portfolio of candidates

and revision of the FRF calculations to reflect the current data and prevailing set of qualitative

assumptions. Figure 63 illustrates the Initial Product Screening methodology and its iterative design.

6.4.2 - Comparative Evaluations

Comparative analyses of proposed bioprocessing routes with current petrochemical routes were

performed at an early stage of process evaluation to help determine the order in which candidates are

investigated in more detail. The basis for this comparison is the estimated raw material costs for each

of the processing routes. The raw material costs are a significant fraction (50-80% or more) of the

production cost for a majority of commodity chemicals. A preliminary economic comparison can be made

between the bioprocessing route and the current petrochemical route assuming the raw material costs

are an approximately equal fraction of the total production costs of each route.

The parameter of interest here is the ratio of the raw material costs. The ratio is modified by a risk

factor of 13 to take into account possible problems, unknowns, and intangiblesin a given bioprocess. One

might also view this factor as accounting for the fact that in most situations the capital required for

144
R&D

Opportunities:

Biological

Improvements

Product

Candidate

Collect

Information

It

EstimateMarket

Values

\

Determine

Maximmn

TheoreticalYield

CalculateFractionof

Revenuefor

Feedstock

Gather

Demonstrated

YieldData

II

CalculateFractionof

Revenuefor

Feedstock

Classify as: Near-, Mid-,

or

Lena-term Opportunitv

Figure 6.3 - Initial Product Screening Methodology

145

Product Demand,

EconomicForecast,

FeedstockAnalysis,

LaboratoryData,

Technicallnformation

QualitativeInfluences
the existing petrochemical-based process is partially or completely paid-off. Thus, any competitive

process would have to have substantially lower production costs.

RawMalerial

Cost Ratio = Estimated CostofRawMalerialsjor Petrochemical Process

Estimated CostofRawMaterialsfor Bioprocess x 1

Risk Factor

If the raw material cost ratio (RMCR) is greater than unity, then the proposed bioprocess shows

potential,'based on raw material costs alone, for being competitive with the existing petrochemical

process. A ratio considerably less than unity indicates that the bioprocess could have difficulty

competing with the current petrochemical route.

Similarly to the FRF calculations, both a currently achievable bioprocess and a theoretical achievable

bioprocess can be considered. The basis for determining the raw materials costs for the currently

achievable bioprocess portion of this analysis is the demonstrated yield factor, based on glucose,

multiplied by 0.5 to adjust for unaccounted raw materials and the uncertainty in translating bench-, or

pilot-scale yield data to production scale. In some cases, this adjustment factor overpenalizes the

bioprocess because some yields have been demonstrated at large scale, and additional raw material

costs are negligible. Nevertheless, it has been kept in all cases for consistency. The basis for

determining the raw materials costs for the theoretically achievable bioprocess part of this analysis is

the theoretical yield factor, based on glucose, multiplied by 0.95. The adjustment factor in this case is

applied to account for the inability of a full-scale process to achieve 100% of the theoretical yield. No

adjustment is made to account for additional raw materials because, in theory, processes could be

developed in which they would no longer be required or would be negligible.

For example, one proposed bioprocess to produce succinic acid requires the addition of base to the

fermentor to maintain an economical volumetric productivity and concentration of succinate. The

resulting succinate salt is then acidified to recover succinic acid. These two raw materials alone

contnbute approximately $0.05 to $0.07 per pound of succinic acid produced. An alternative process has

been developed that uses water-splitting electrodialysis to form an aqueous succinic acid solution and a

base that can be recycled back to the fermentor, thereby eliminating the acid and base raw material

costs.

Only the currently achievable petrochemical processes were considered. Assuming that these processes

have already been fully optimized and that additional process improvements would not be costeffective. The basis for determining the raw material costs for the petrochemical processes is the

current demonstrated yield factor, based on the primary precursor. This data was obtained from the

literature, the majority from the Stanford Research Institute's Chemical Economic Handbook. No

adjustment factor was applied to the yield factor because all raw material costs are assumed to be

known and the yield is clearly demonstrated at full scale. A point to keep,in mind is that true yield

and raw material cost data for many commercial processes are proprietary and thus unavailable.

Therefore, these numbers could be significantly different than the data used in the comparative

analyses.

Rather than examining various feedstocks, as was done for the FRF calculations, a range of glucose costs

was used to determine the raw material costs for the bioprocesses. The source of this glucose could be,

for example, from com (hydrolyzed starch), from lignocellulosic biomass (hydrolyzed cellulose), or

from an industrial waste stream containing recoverable amounts of starch, cellulose, or their

hydrolysates. The range of glucose costs evaluated was from $0.05 to $0.13 per pound, although the cost

could be lower, conceivably even negative for some waste streams. Thus, two RMCR curves were

generated for each product, one for current yield and one for theoretical yield, both versus the cost of

glucose.

146
Most bioprocesses require the addition of various nutrients, such as com steep liquor as a nitrogen source

or air as an oxygen source for aerobic organisms. The cost of these nutrients is usually small compared to

the feedstock cost. However, rather than omit these costs, they have been estimated and included as

20% of the feedstock cost. .

These comparative analyses should be viewed only as a first attempt to compare the competitiveness of

bioprocesses with the current petrochemical-based processes, and will be used only to help identify the

order in which more detailed engineering economic analyses will be performed. A comparison of the

more detailed engineering analyses will provide a better measure of the competitiveness of the

bioprocessing route. These detailed engineering analyses also will be used to identify key research

opportunities for bridging the competitiveness gap between bioprocesses and petrochemical processes.

6.4.3Integrated PmdudlProcess Screening Methodology

The effort required to complete this stage of screening is significantly greater than that for the initial

product screening. The ranked results from the initial product screening stage can be used to rank the

order in which candidates undergo the more rigorous integrated product/process screening. In the second

stage of the analysis, as in the first stage, the objective is to classify the candidates 'and associated

process technologies as near-, mid-, or long-tenn opportunities.

The second stage of the screening analysis requires a complete process design. During this phase of the

analysis, an order-of-magnitude level of detail is sufficient. In other words, the actual fixed capital

investment for a project is assumed to be within ±30% of the estimated value. The factoring method is

used to determine the various fixed and variable costs from independently determined purchased

equipment, raw material, and operating labor costs. A reasonable allowance for return on investment

must also be made.

A discounted-eash-flow analysis is used to predict the selling price of the product. The processes then

are ranked based on the difference between the estimated market value and the predicted selling price.

The rankings from the three screening stages will likely be different. The ranking from the third

screening stage will be the most accurate because many more details are considered. However, the

results of all rankings, together with qualitative input, will be used. to determine the final project

classifications into near-, mid-, and long-term opportunities.

It is important to point out that the screening methodology in general is an iterative process. As

biological and process improvements unfold, and the screening methodology and criteria evolve, the

rankings of the candidates and technologies will change.

6.4.3.1 Process Design

The first step in performing the integrated product/process screening analysis for a project is completing

a process design. A number of plant designs and design assumptions can be considered for each candidate

in this stage of screening. The proper choice will depend on a number of factors induding the process

technology, the projected product demand, and the intended purpose for the results of the analysis.

The first and simplest design basis is an independent bioconversion plant. A wide variety of feedstocks

could be considered for this type of design, such as sugar syrups, whey and whey hydrolyzates, and

industrial wastes. These feedstocks require little or no pretreatment to convert them to fermentable

substrates. The assumed cost of the feedstock could be its current market or contract value, an estimated

transfer price, or its tipping fee in cases of waste streams.

A second design basis is a bioconversion facility integrated with a plant that produces one or more

streams of fermentable substrates and perhaps other nonfermentable products or byproducts. An

example of such a plant is a corn milling facility. A wet-milling facility produces a hydrolyzed starch

147
slurry as the fermentation feedstock. Some of the light steep water is used as a nutrient source for the

fermentation process. The remaining light steep water is concentrated and sold as com steep liquor or

added to the gluten feed, another process coproduct. Other coproducts from the wet-milling operation

are crude com oil and com gluten meal. .

Another integrated plant example is a bioconversion facility integrated with a lignocellulosic

processing plant. The feedstock to this plant could be any form of lignocellulosic biomass. A variety of

process technologies exist to convert the cellulose and hemicellulose fractions of biomass to fennentable

sugars.

The process design includes performing material and energy balances and specifying and sizing the

process equipment. When all of the equipment is specified, the purchase price is estimated using

ICARUS' Questimate PC-based process equipment costing software, estimated from historical data

updated to the reference year; or obtained through equipment vendors. Various cost multiplication

factors are applied when necessary; for example, when specialized construction materials or

construction for high-pressure conditions are required.

The initial process designs, material and energy balances, and profitability analyses are performed

using PC-based spreadsheet software (Microsoft Corporation's Excel 4.0). More rigorous material and

energy balances can be performed using an ASPEN process simulator.

6.4.3.2 Profitability Analysis

An economic model was developed to perform the profitability analyses. The model uses the

discounted-eash-flow method to calculate the profitability of the process. This method is most

frequently used in the chemical process industry for the initial assessment of a project's economic

potential. The method is predominant because it takes into account the time value of money. According

to this principle, receiving a dollar in income today is worth more than receiving a dollar next year

because today's dollar could be invested and next year be worth one dollar plus the interest earned.

With any project the investment may be made over a period of time; the income will be generated over

a longer period of time and often will be quite variable. The discounted cash flow method relates all

aspects of the cash flow to a common time basis. The basis used for this model is the time at which the

plant starts operation after an assumed 1-,2-, or 3-year period of construction.

Specifically, the discounted-cash-flow rate of return is a hypothetical interest rate such that, when it

is used to calculate the present value of all of the income cash flow for each year plus all of the capital

expenditure, the present value is zero. In other words, it is the interest rate that would be received if

the same capital investment funds were to be placed in a bank for a given period (the life of the plant)

and earned the same amount in interest as the cash flow produced by the plant.

The standard procedure for calculating discounted cash flow is to first tabulate all the cash flows

involved with the project and then discount them to the reference time value by an assumed interest

rate. These discounted present values are added together and the process is repeated with different

interest rates until the sum of the discounted cash flows is zero. That interest rate is the discounted

cash flow (DCF) or internal rate of return ORR) for the project. This trial-and-error calculation is

based on establishing appropriate compound interest discount factors for each cash flow to bring its

value to the reference time value.

This approach is based on the assumption that all the cash flows, including the revenue, can be

determined. However, the revenue can be calculated only if the product selling price is known. If the

selling price is to be determined, the DCF is set to the minimum acceptable rate and trial-and-error

calculations are performed with product selling price as the variable. Once the product selling price is

148
determined, all the discounted cash flows sum to zero. This price is compared to the current or estimated

market value in order to classify the project as a near-, mid-, or long-term opportunity.

6.4.3.3 Economic Assumptions

A set of economic parameters was defined to be used as the basis for the base-case process designs.

Applying this set of assumptions to aD of the process designs ensures that all the projects are evaluated

on a common ground. Table 6.4 lists the most important of these parameters. Note that most of these

parameters can be varied in sensitivity studies, (Section 6.4.3.4).

Table 6.4 - Technical and Economic Assumptions

.- ..

Parameter

Plant Location

Plant Type

Effective Date

Plant Life, years

Materials of Construction

Equipment Depreciation MACRS Service Life

Building Depreciation (straight-line)

Combined Federal and State Tax Rate

Equipment Salvage Value (percent of purchase cost)

Discounted-Cash-Flow Rate of Return

Inflation Rate

Percent of Capital Investment Spent in the 1st year of Construction

Percent of Capital Investment Spent in the 2nd year of Construction

Percent of Capital Investment Spent in the 3rd year of Construction

Percent of Start-up Costs Spent in the 3rd year of Construction

Plant Capacity, as a percentage of nameplate capacity, in year 1

Plant Capacity, as a percentage of nameplate capacity, in year 2

Plant Capacity, as a percentage of nameplate capacity, in years 3-life

6.4.3.4 Sensitivity Analyses

Assumption

Midwest

"Grass Roots"

1992

10

Stainless Steel, 316L

5 years

30 years

37%

0%

15%

3.5%

30%

50%

20%

30%

60%

80%

100%

Various sensitivity analyses can be perfonned to detennine where the economics of the process might be

improved. The predicted product selling price is detennined for distinct values in some range of process

parameter variations around the base-ease value. Examples of the general parameters most often

varied in sensitivity studies include plant size, plant cost, raw material costs, working capital, sales

volume, sales price, and return on investment. Examples of case-specific parameters that might be

varied in sensitivity studies include process stream concentrations, reaction rates, conversion yields,

nutrient requirements, energy requirements and costs. The results of sensitivity studies are most often

displayed graphically in Figure 6.4.

6.4.3.5 Summary

The objective of the integrated product/process screening stage is to provide a more rigorous assessment

of both the technical and economic feasibility of a project. Like the initial product screening stage, it is

an as-simplified-as-possible methodology to give the desired results. The purpose is not to prepare

extremely detailed and costly process designs, but to provide another quantitative measurement by

which Projects can be ranked. Detailed designs and rigorous profitability analyses are future activities

performed on portfolio candidates whose manufacturing technology becomes ripe for commercialization.

149
50%

40%

30%

20%

Variable of

Interest 10-/0

[pen:entchange

from base case 0%

analysis]

-10%

-20%

·30%

-40%

-6()0/. -40% -20% 0% 20% 40% 60%

Sensitivity Parameter

(percent change from base case analysis)

Figure 6.4 - Generic Example of Sensitivity Analysis

Also in common with the initial product screening stage is the iterative nature of the integrated

product/process screening stage. In addition to factors that influenced the calculation of the FRF, a

number of other factors come into consideration during this stage of the analysis. Parameters that

affect the manufacturing costs will change periodically, some much more rapidly than others.

Demonstrated new technology concepts for bioconversion systems and product purification and recovery

operations may catapult a process from the ranks of a long-term opportunity to those of mid- or nearterm opportunities. Constantly changing technologies, and revised economic forecasts, will necessitate

continual re-evaluation of the projects at this level of analysis.

Figure 6.5 illustrates the integrated product/process screening methodology and its iterative design.

150
Product Candidate Define General

Process

Obiective

Collect

Information Product Demand,

EconomicForecast,

t Raw Materials,

Synthesize Flowsheet LaboratoryData,

U of Techmcalbnonnation

--I Process Operations QualitativeInfluences

SelectEquipment

U ,

Types

1

Define Operating

--IU Conditions

t

PerformMaterial R&D

and Opportunities:

EnerzvBalances

t Biological,

Size Process Process

Equipment Improvements

1

Estimate Capital arid

OperatingCosts

t

PerformProfitability

Analysis

1

PerformSensitivity

Analysis

t

PerformOptimization

Analysis

Classify As: Near-, Mid-, or

Long-term Opportunity

Figure 6.5 - Integrated ProductlProcess Screening Methodology

151
-:i.~ . ' .

7.0 RESULTS OF INITIAL ANALYSIS

7.1 Initial Targets

The initial bioprocessing program portfolio is made up of 40 chemicals and materials. They are listed

in alphabetical order in Table 7.1 along with their market values and consumption (where known).

Note that the market values are based on demand and may be significantly higher than the actual cost

of production.

As mentioned in sections 6.4.1.4 and 6.4.1.5, experimental yields were obtained from the literature and

theoretical Yields were calculated. Table 7.2 compares the experimental yield with the theoretical

yield. The units of the Yieldare mass of product formed per mass of substrate consumed.

7.2 Applying Prioritization Methodology

The FRF was calculated for the 40 candidates for a number of feedstocks. The results of the calculations

using wet-milled corn and hybrid poplar are reported below. These calculations were done once using

demonstrated yields and once using the maximum theoretical Yields.

Again, the lower the FRF, the greater the value of the products compared to the cost of the feedstock.

H the FRF is unity, the value of the products just equals the value of the feedstock used. If the FRF is

greater than unity, the products are worth less than the feedstock. Arbitrary project classifications

into one of the time-frame opportunity categories can be made based on the FRF. For example, if the

FRF using demonstrated yield data with corn as the feedstock is. below a certain value, then that

candidate might be classified as a near-term opportunity. Similarly, 'if the FRF is below the cut-off

value using the theoretical yield data with corn as the feedstock, or using demonstrated yield data

with hybrid poplar as the feedstock, the candidate might be classified as a mid-term opportunity.

Candidates whose FRF is below the cut-off when using theoretical yield data with hybrid poplar as

the feedstock might be classified as long-term opportunities. All other candidates would be classified

as very long-tenn opportunities.

Demonstrated Yield Theoretical Yield

Cmn Near-Tenn Opportunity if FRF Mid-Term Opportunity if FRF

less than e less 8

Hybrid Poplar Mid-Term Opportunity if FRF Long-Term Opportunity ifFRF

less than 8 less than 8

The preceding classification scheme could be generalized to have broader biological and process

improvements as its bases. The cut-off criterion may be a parameter such as the difference between the

estimated product selling price and the estimated market value, or perhaps the ratio of these two

estimates. This is the kind of analysis that will be performed during the third screening stage.

Current Biological Performance Theoretical Biological

Performance

CUlI'eDt ProcessPerformance Near-Term Opportunity if Mid-Tenn Opportunity if

Criterion is Satisfied Criterion is Satisfied

rt"heoreticalProcess Performance Mid-Term Opportunity if Long-Term Opportunity if

Criterion is Satisfied Criterion is Satisfied

153
Table 7.1- Bioprocessing Element Product Portfolio Candidates and MarketValues

Price Domestic Price Domestic

Candidate 1iLThl Consumptiona Candidate !WJll Consurnptiona

Acetaldehyde 0.46 561 Isopropanol 0.36 1,209

Acetic Acid 0.33 3,410 Itaconic Acid 1.00

Acetone 0.34 2,178 Lactic Acid 035 40

Acrylic Acid 0.69 1,000 Lysine 1.20 37

Adipic Acid 0.65 1,567 Malic Acid 0.81 14

Alginate 1.00 14 Oleic Acid 0.62 30

Ascorbic Acid 1.00 32 Polyhydroxybutyric Acid 0.50

Azelaic Acid 0.69 l,3-Propanediol 0.60

Bacterial Cellulose 1.00 Propionic Acid 0.41 100

2,3-Butanediol 0.90 Propylene Glycol 0.58 621

Butanol 0.41 1,016 Protease 1.00

Butyraldehyde 0.43 2,()63 Pullulan 1.00

. .' Butyric Acid 0.48 30 Rhamsan 1.00

Cellulase 1.00 Scleroglucan 1.00

Citric Acid 0.82 332 Sorbitol 0.36 400

Dextran 1.00 Succinic Acid 0.35

Fumaric Acid 0.67 33 Surfactin 0.75

Gluconic Acid 0.90 5 Tartaric Acid 1.00 4

Glycerol 0.58 340 XanthanGum 1.00 25

Hyaluronic Acid 0.50 Xylitol 0.40

aDomestic consumption in millions of pounds/year.

Table 7.2 - Portfolio Candidate Yields: Demonstrated and Theoretical

Candidate Xex Xth Candidate Xex Xth

Acetaldehyde N/A 0.59 Isopropanol 0.12 0.33

Acetic Acid 0.50 0.67 Itaconic Acid 0.65 0.72

Acetone 0.12 0.48 Lactic Acid 0.95 1.00

Acrylic Acid N/A 0.80 Lysine 0.50 0.70

AdipiC Acid N/A 0.75 Malic Acid 0.56 1.12

Alginate 0.52 0.90 Oleic Acid 0.05 0.37

Ascorbic Acid 0.01 0.98 Polyhydroxybutyric Acid 0.40 0.47 -..."j

Azelaic Acid N/A 0.52 1,3-Propanediol 0.80 0.42

Bacterial Cellulose 0.25 0.90 Propionic Acid 0.46 0.55

2,3-Butanediol 0.33 0.50 Propylene Glycol 0.27 0.42

Butanol 0.25 0.41 Protease 0.10 N/A

Butyraldehyde N/A 0.40 Pullulan 0.43 0.90

Butyric Acid 0.38 0.49 Rhamsan 0.40 0.90

Cellulase 0.27 N/A Scleroglucan 0.36 0.90

Citric Acid 0.87 1.07 Sorbitol 0.36 0.93

Dextran 0.30 0.53 Succinic Acid 0.87 0.98

Fumaric Acid 0.72 0.97 Surfactin 0.02 N/A

Gluconic Acid 0.90 1.09 Tartaric Acid 0.05 0.83

Glycerol 0.50 0.88 XanthanGum 0.60 0.90

Hyaluronic Acid 0.25 0.65 Xylitol 0.12 0.84

154 .
1

Tables 7.3 and 7.4 give the results of the FRF calculations for the 40 candidates. If a demonstrated

yield was not currently available in the literature, the FRF calculation was not performed. In the cases

of protease and cellulase, the theoretical yield was not calculated because these products are enzyme

complexes, not single species, and no single product formation reaction can be written. Thus, the FRF

calculation could not be performed for these candidates using a theoretical yield. Table 7.s gives the

results of an initial classification based on the FRF alone. Arbitrary FRF cut-off limits of 0.15, 0.20,

and 0.25 were chosen. These results, when combined with various other qualitative factors and

comparative analyses with existing processes, can be used to determine the order in which the processes

are investigated in more depth.

155
Table 7.3- FR.F Results using Wet-Milled Com as the Feedstock

Candidate FRFex FRF.lt Candidate FRFex FRF'h

Acetaldehyde N/A 0.20 Isopropanol 0.73 0.38

Acetic Acid 030 0.24 Itaconic Acid 0.09 0.08

Acetone 0.75 0.30 Lactic Acid 0.16 0.16

Acrylic Acid N/A 0.10 Lysine 0.09 0.07

Adipic Acid N/A 0.11 Malic Acid 0.13 0.06

Alginate 0.11 0.06 Oleic Acid 0.86 0.23

Ascorbic Acid 1.15 0.06 Polyhydroxybutyric Acid 0.25 0.22

Azelaic Acid N/A 0.15 1,3-Propanediol 0.12 0.21

Bacterial Cellulose 0.21 0.06 Propionic Acid 0.27 0.23

2,3-Butanediol 0.18 0.12 Propylene Glycol 0.31 0.21

Butanol 0.43 0.29 Protease 0.43 N/A

Butyraldehyde N/A 0.28 Pullulan 0.13 0.06

Butyric Acid 0.28 0.22 Rhamsan 0.14 0.06

Cellulase 0.19 N/A Scleroglucan 0.15 0.06

~: Citric Acid 0.08 0.07 Sorbitol 0.36 0.16 . "

Dextran 0.18 0.11 SuccinicAdd 0.18 0.16

Fumaric Acid 0.12 0.10 Surfactin 1.17 N/A

Gluconic Acid 0.07 0.06 Tartaric Acid 0.67 0;07

Glycerol 0.18 0.11 XanthanGum 0.09 0.06

Hyaluronic Acid 037 0.17 Xylitol 0.70 0.16

Table 7.4- FR.F Results using Hybrid Poplar as the Feedstock

Candidate FRFex FRF.lt Candidate FRF~ FRF'h

Acetaldehyde N/A 0.13 Isopropanol 0.57 0.27

Acetic Acid 0.20 0.16 Itaconic Acid 0.06 0.05

Acetone 0.58 0.20 Lactic Acid 0.11 0.10

Acrylic Acid N/A 0.07 Lysine 0.06 0.04

Adipic Acid N/A .~ Malic Acid 0.08 0.04

Alginate 0.07 0.04 Oleic Acid 0.69 0.15

Ascorbic Acid 1.01 0.04 Polyhydroxybutyric Acid 0.17 0.15

Azelaic Acid N/A 0.10 .1,3-Propanediol 0.08 0.14

Bacterial Cellulose 0.14 0.04 Propionic Acid 0.18 0.15

2,3-Butanediol 0.12 .~ Propylene Glycol 0.21 0.14

Butanol 030 0.20 Protease 0.31 N/A

Butyraldehyde N/A 0.20 Pullulan 0.09 0.04

Butyric Acid 0.19 0.15 Rhamsan 0.09 0.04

Cellulase 0.13 N/A Scleroglucan 0.10 0.04

Citric Acid 0.05 0.04 Sorbitol 0.25 0.11

Dextran 0.12 0.07 SuccinicAcid 0.01 0.01

Fumaric Acid 0.08 0.06 Surfactin 1.04 N/A

Gluconic Acid 0.05 0.04 Tartaric Acid 0.52 0.05

Glycerol 0.12 0.07 XanthanGum 0.06 0.04

Hyaluronic Acid 0.26 0.11 Xylitol 0.54 0.11

156
Table 7.s ..Initial Candidate Classification

FRF Cut-oFF

Candidate

Acetaldehyde

Acetic Acid

Acetone

Acrylic Add

Adipic Acid

Alginate

Ascorbic Add

Azelaic Acid

Bacterial Cellulose

Butanediol, 2,3-

Butanol

Butyraldehyde

Butyric Acid

Cellulase

Citric Acid

Dextran

Fumaric Acid

Gluconic Acid

Glycerol

Hyaluronic Acid

Isopropanol

Itaconic Acid

Lactic Acid

Lysine

Malic Acid

Oleic Acid

Polyhydroxybutyric Acid

Propanediol,l,3-

Propionic Acid

Propylene Glycol

Protease

Pullulan

RhamsanGum

Scleroglucan

Sorbitol

Succinic Acid

Surfactin

Tartaric Acid

XanthanGum

Xylitol

0.15

Very Long

Very Long

Very Long

Mid

Mid

Near

Mid

Very Long

Mid

Mid

Very Long

Very Long

Very Long

Near

Mid

Near

Near

Mid

Very Long

Very Long

Near

Near

Near

VeryLong .

Very Long

Near

Very Long

Very Long

Very Long

Near

Near

Mid

Very Long

Very Long

Mid

Near

Very Long

157

0.20

Mid

Very Long

Very Long

Mid

Mid

Near

Mid

Mid

Mid

Near

Very Long

Very Long

Near

Near

Near

Near

Near

Near

Mid

Very Long

Near

Near

Near

Near

Very Long

Near

Very Long

Very Long

Near

Near

Near

Mid

Near

Very Long

Mid

Near

Mid

0.25

Mid

Mid .

Very Long

Mid

Mid

Near

Mid

Mid

Near

Near

VeryLong

Very Long

Mid

Near

Near

Near

Near

Near

Near

Mid

Very Long

Near

Near

Near

Near

Mid

Mid

Near

Mid

Mid

Very Long

Near

Near

Near

Mid

Near

Very Long

Mid

Near

Mid
.....: . "'

7.3 Comparative Evaluations

This section contains a series of comparative analyses of proposed bioprocessing routes and current

petrochemical routes. Although there are 40 product candidates in the bioprocessing element portfolio,

only 12 were evaluated in this comparative analysis. Many candidates in the portfolio are produced

solely through bioprocessing routes; for example lysine or pullulan gum. Others are currently produced

through bioprocessing, although a Petrochemical Process is available, for example, citric acid. Some

candidates, though theoretically possible to produce through bioprocesses, have no proposed

bioprocess, and thus yields and raw material costs for these processes cannot be determined.

These comparative analyses should be viewed as a first attempt to compare the competitiveness of

bioprocesses with the current petrochemical-based processes.

Preliminary evaluations of the bioprocesses compared to the conventional petrochemical-based

processes were performed slightly differently than the comparative evaluations of thermal!chemical

biomass-based processes and petrochemical-based alternative processes. The main difference is that

the raw material costs were estimated and used in the calculations rather than the raw material cost

contribution. Another difference is that a range of bioprocessing feedstock costs were considered.

An example of the raw material cost ratio is given for two cases. Both cases assume the glucose cost to

be $O.075/lb. This is an estimated transfer price of glucose from a com wet-milling facility. The first

case is for currently achievable bioprocess technology. The second case is for theoretically achievable

bioprocess technology.

Also included in each analysis is a chart showing the sensitivity of the raw material cost ratio of each

product to the cost of the glucose. Both currently achievable and theoretically achievable bioprocess

technology scenarios are shown on these charts.

158
7.3.1 Acetic Acid

Bioprocess:

Microorganisms, nutrients

Glucose Aerobic

fermentation

Water

+ +

Air

Petrochemical process:

Methanol Catalytic

carbonylation

Recovery,

purification

ACETIC

ACO

Processes Compared: The bioprocess is an aerobic fennentation of glucose, with about 50% conversion to

acetic acid. The process is economically favorable if the cost of glucose is sufficiently low.

In the hydrocarbon-based route, the currently predominant acetic acid process is direct carbonylation of

methanol, which is manufactured from natural gas-derived syn gas (carbon monoxide plus hydrogen).

The conversion of methanol is essentially 100%.

Raw Materials Cost Comparison: In the bioprocess, with a glucose raw materials cost of $0.075/1b and

95%conversion, the raw materials cost is SO.300/lb of acetic acid.

In the manufacture of acetic acid from methanol, with 100%conversion of methanol, the raw material

cost is $0.131/1b of acetic acid. This estimate is based on $1.60/million BTU natural gas.

Comparison of the costs of the hydrocarbon and bioprocess routes gives the ratio

($0.131)/($0.300) = 0.44

and when a "risk" factor of 1.3 is included, the ratio becomes

0.44/1.30 = 0.34.

Therefore, the bioprocess route does not pass the screening test.

159
Future Projections: Potential biological and process improvements could reduce the raw materials cost

for the bioprocess to $0.118/lb of acetic acid. Recomparison of the costs of the hydrocarbon and

bioprocess routes gives the ratio

($0.131)/($0.118) = 1.11

and when a "risk" factor of 1.3 is included, the ratio becomes

1.11/1.30 = 0.86.

Acetic acid from glucose comes close to passing the screening test and might compete in future capacity

expansions if the glucose raw material cost can compete with natural gas-derived syn gas, and/or if the

necessary process improvements can be realized (see Figure 7.1).

3.00

2.50

2.00

' " --.._-_._------- -.-.-....---.

0.34

-~- .....•...,._..... 0.86

-,.----- ---......

0.50 r-----.

-----;;--------1

1.00

E&timated

Raw

Material

Cost 1.50

Ratio

IJICIadiDg

Risk Factor

0.00

$0.05 $0.06 $0.07 $0.08 $0.09 $0.10 $0.11 $0.12 $0.13

Glucose Cost

[$/lb)

---CUncmIy AclDcYahle --_._._.- 'IbooteUcally Aem.-bIc

Figure 1.1- Estimated Raw Material Cost Ratio versus Glucose Cost, Acetic Acid Production

160
,.3.2 Acetone

Bioprocess:

Microorganisms, nutrients

"

Ethanol Butanol

.., ': .

Glucose Anaerobic

fermentation

Water +

Petrochemical process:

Recovery,

purification --~.-~ ACETONE

Cumene

oxidation

Oxygen

t

Propylene" BAlkylation -...-j_~

Benzene ...__....

Sulfuric

acid

Splitting, I-_".~ ACETONE

recovery

,

Phenol

Processes Compared: In the bioprocess, acetone, butanol and ethanol are coproduced. by fennentation of

glucose in wt% yields of 9%, 23% and 2%, respectively, for a total coproduct yield of 34%, based on

glucose. If glucose is valued at a cost of SO.075/lb, the raw materials cost is $1.25/lb of the acetone,

butanol, and ethanol mixture.

Acetone is a coproduct, with phenol, of the oxidation of isopropyl benzene (cumene), which is made in a

highly efficient alkylation of benzene with propylene. If all the propylene is assumed to be converted

to acetone, the raw materials cost is $O.129/1b of acetone, with propylene valued at SO.135/lb.

The ratio of the hydrocarbon-based process and bioprocess raw materials cost is then

($0.129)/($1.25) = 0.10,

and when a "risk" factor of 1.3 is included, the ratio becomes

0.10/1.3 = O.~-

It would be difficult for the bioprocess to compete with the existing petrochemical route, primarily

because of the low yield of useful fermentation coproducts and the relatively much lower cost of the

hydrocarbon feedstocks. Any RD&D effort must address these yield differences between the two routes.

161
Future Projections: Potential biological and process improvements could reduce the raw materials cost

for the bioprocess to SO.164/1bof acetone. Recomparison of the costs of the hydrocarbon and bioprocess

routes gives the ratio

($0.129)/($0.164) = 0.79

and when a "risk" factor of 1.3 is included, the ratio becomes

0.79/1.30 = 0.61.

Acetone via fermentation of glucose will have difficulty competing in future capadty expansions unless

a low-cost source of glucose is available (see Figure 7.2).

. 3.00

2.50

2.00

Estimated

Raw

Material

Cost 1.50

Ratio

lDdadiDg

Risk Factor

1.00

--.._-...

" . " . '"

0.50

0.00

-'._._ 0.6\ .•._-........-.__...-

........_-_.._----_._-_...._------_._._.._- -- ------

0.08

$0 .05 $0.06 $0.07 $0.08 $0.09

Glucose Cost

[$Ilb]

$0.10 $0.11 $0.12 $0.13

---.Cum:DIy AdIicvaItIc .._ .-.-_...•••. n-etically AcbioYabIc

Figure 7.2 - Estimated Raw Material Cost Ratio VelSUS Glucose Cost, Acetone Production

162
7.3.3 2,3-Butanediol

Bioprocess:

Microorganisms, nutrients

Glucose Anaerobic

fermentation

t

Water

Recovery,

purification

t

Ethanol,

residues

--... 2,3 BUTANEDIOL

...---.....- ..~Chlorine Chlorohydrination

.... .._-:_-_-_-:--...."- Water

• C-4raffinate .,

Petrochemical process:

INatural Uquids GasI.. IThsma11 Cracking

Sodium

hydroxide

Cyclization,

hydrolysis

Recovery,

purification • 2,3 BUTANEDIOL

Sodium

chloride

Processes Compared: 2,3-Butanediol is a small-volume, specialty chemical that is used as a resin

crosslinking agent and as a precursor to insecticides and pharmaceutical products; its future as a

commodity is unclear.

The bioprocess is a fermentation of glucose with coproduction of 2,3-butanediol and ethanol.

The hydrocarbon-based processis based on a 4-step conversion of the "C-4 raffinate" from hydrocarbon

cracking (ethylene process) and consists of: (1) chlorohydrination (90% yield); (2) cyclization with

caustic (90% yield); (3) hydrolysis (90% yield); and (4) vacuum fractionation (90% yield). The major

raw materials consumed are butenes, chlorine and caustic.

Raw Materials Cost Comparison: In the glucose fennentation process, there is an estimated 75% yield

of coproduct ethanol and 2,3-butanediol. Using a glucose raw materials cost of $0.075/Ib and a recovery

yield of 85%, and spreading costs over the two coproducts, the raw materials cost is $0.455/1b of 2,3-

butanediol and ethanol.

In the hydrocarbon-based process, the raw materials costs for butenes, chlorine, and caustic are $0.087,

$0.08 and $0.19, respectively, per Ib of 2,3-butanediol, for a total raw materials cost of $0.357/lb, based

on the reported yields of the process. The ratio of the hydrocarbon-based and bioprocess raw materials

cost is then

($0.357)/($0.455) = 0.78,

and when a "risk" factor of 1.3 is included, the ratio becomes

0.78/1.3 = 0.60.

163
Future Projections: Potential biological and process improvements could reduce the raw materials cost

for the bioprocess to $O.l58/lb of 2,3-butanediol. Recomparison of the costs of the hydrocarbon and

bioprocess routes gives the ratio

($0357)/($0.158) = 2.26

and when a "risk" factor of 1.3 is included, the ratio becomes

2.26/130 = 1.74.

A low-cost source of glucose together with biological and process improvements could make the 2,3-

butanediol bioprocess a viable alternative to the petrochemical route (see Figure 7.3).

3.00

2.50

" " ' "

-,

2.00

Emmated

Raw

Materia1

Cost 1.50

Ratio

' ......diac

RiskF8Ctor

1.00

< ,

""

....... 1.74

... .....-..

..............

-"-- -._-.._--- ...-....-._._..-

0.50

0.00

SO.05 SO.06 $0.07 SO.08 $0.09 SO.10 $0.11 $0.12 $0.13

Glucose Cost

[$Jlb]

---eun-Jy ..- n.-i<:aIIy Acbiev.IbIe

Figure 7.3 - Estimated Raw Material Cost Ratio VeISUS Glucose Cost, 2,3-Butanediol Production

164
r .

7.3.4 Butanol

Bioprocess:

Microorganisms, nutrients

"

Ethanol Acetone

Glucose Anaerobic

fennentation

t

Water

Petrochemical process:

Recovery,

purification ---.,~- BUTANOL

Syngas

Pro 1 Catalytic py en~ Hydroformylation --...-- hydrogenation Recovery,

purification

lsobutanol

• BUTANOL

Processes Compared: Hydrocarbon-based n-butanol is made in two steps: (1) hydroformylation (oxo) of

propylene with syn gas to mixed butyraldehydes, and (2) catalytic hydrogenation of the aldehydes to

mixed coproduct iso- and n-butanol; n-butanol is recovered and purified by distillation. The raw

materials cost is $O.323/lb of n-butanol, with propylene valued at $0.135/lb and syn gas at

$2.29/thousand standard cubic feet.

The raw materials cost for the bioprocess is $O.60/lb of n-butanol (see section 7.3.2). The ratio of the

hydrocarbon-based and biomass raw materials cost is then

($0.323)/($0.60) =0.54,

and when a "risk" factor of 1.30is included, the ratio becomes

0.54/1.30 = 0.41.

The biomass process would have difficulty competing with the existing petrochemical route, primarily

because of the low yield of useful fermentation coproducts and the relatively much lower cost of the

hydrocarbon feedstocks. RD&Dmust address these yield differences between the routes.

165
Future Projections: Potential biological and process improvements could reduce the raw materials cost

for the bioprocess to $O.193/lb of n-butanol. Recomparison of the costs of the hydrocarbon and bioprocess

routes gives the ratio

($0357)/($0.193) = 1.67

and when a "risk" factor of 1.3 is included, the ratio becomes

1.67/130 =1.29.

Lower glucose costs and biological and process improvements could make the acetone-butanol-ethanol

bioprocess economically viable (see Figure 7.4).

3.00

2.50

2 .00

Estimated ,-

Ra"

Material "

Cost 1.50

Ratio

IDcladillg

Risk Factor

1.00

........ ' 00 \.29

......._-- ........

-'-'" ............

.._-..__ -.

0 .00

$0.05 $0.06 SO.07 SO.08 $0.09

Glucose Cost

[$lIb]

SO.10 $0.11 $0.12 $0.13

---Cum:zlIlyAcbX:vabIc _ AdlicaDIc

Figure 7.4 - Estimated Raw Material Cost Ratio versus Glucose Cost, Butanol Production

166
7.3.5 Butyric Acid

Bioprocess:

Water Calcium

carbonate

Sulfuric

acid

• Neutralization/ .. Recovery, .. BVlYRIC

filtration purification ACID

, ,

Calcium Acetic acid,

sulfate residue

Petrochemical process:

Oxygen

" proPYlen~1 Hydroformylation I ., Butyraldehyde Recovery,

oxidation purification

,

Acetic acid,

residue

., BUTYRIC

ACID

Processes Compared: In the bioprocess, an anaerobic fermentation of glucose, using limestone for pH

control and sulfuric acid for neutralization, gives an overall 46%yield of butyric acid, based on glucose

feedstock. Acetic acid is a coproduct.

Hydrocarbon-derived butyric acid is manufactured by oxidation of butyraldehyde, with propylene as

the principal raw material. The yield is 90% to butyric acid, based on butyraldehyde.

Raw Materials Cost Comparison: In the bioprocess, raw materials cost based on the yield of the

reaction is $O..395/lb of butyric acid. In the butyraldehyde oxidation process, total raw materials cost

is $O.215/lb of butyric acid. Assumed basic raw materials costs include $O.135/1b for propylene and

$2.29/ thousand standard cubic feet for synthesis gas. The ratio of raw materials costs is then

($0.215)/ ($0395) =0.54

and when a "risk" factor of 13 is added, the ratio becomes

0.54/13 =0.42

The bioprocess would have difficulty competing with the existing petrochemical route, primarily

because of the low yield of useful fermentation coproducts and the relatively much lower cost of the

hydrocarbon feedstocks. Any RD&:D effort must address these yield differences between the two routes.

167
Future Projections: Potential biological and process improvements could reduce the raw materials cost

for the bioprocess to $0.161/lb of butyric acid. Recomparison of the costs of the hydrocarbon and

bioprocess routes gives the ratio

($0.215)/($0.161> = 1.34

and when a "risk" factor of 1.3 is included, the ratio becomes

1.34/1.30 = 1.03.

Biological and process improvements could make the butyric acid bioprocess competitive with the

petrochemical process. A low-cost source of glucose would widen the competitive gap in favor of the

bioprocess (see Figure 7.5).

3.00

2.50

2.00

._-.........__ _ __ _- ......................-. .

.-.......-......-.........

0.42

1.03 .........

.~..~-

.. -....

0.50 r--------~~-----l

1.00

Estimated

Raw

Material

Cost 1.50

Ratio

IDdadiag

RiskFaetor

0.00

SO.05 SO.06 SO.07 SO.08 SO.09 SO. 10 SO. 11 SO.12 SO.13

Glucose Cost

[$lIb]

---Cum:ully Ae:m-I>lo -••...• -•.........._.•- 'I'bootcIically Ae:m-l>1o

Figure 7.s - Estimated Raw Material Cost Ratio versus Glucose Cost, Butyric Acid Production

168
7.3.6 Glycerol

Bioprocess:

Microorganisms,nutrients

Recovery, ::: GLYCEROL purification

--.... GLYCEROL

,

Byproducts

Recovery,

purification

Epichlorohydrin

hydrolysis

Calcium

T~

ICausticizalionI ...._--_.. .._-_..

Water --...

Glucose Aerobic

fermentation

Water

+ +

Air

Petrochemical process:

Chlorine ~l .. I Allyl chloride Propylen~ Chlonnation hydration

Processes Compared: Glycerol is now manufactured from "natural" sources (mostly animal fats) or by

one of several existing synthetic routes. End uses determine the split. Because "natural" glycerol is a byproduct of soap, fatty acid, and detergent alcohol production, its availability is dependent on demand

for those products rather than on total glycerol demand. Thus, historical fluctuations in natural

glycerol production mainly reflect demand for detergent alcohol (from natural sources), soap, and fatty

acid in those years. Because natural glycerol is a by-product, it is sold at the highest price that will

ensure its total disposition. Consequently, the market available to synthetic glycerol is detennined by

the total glycerol demand minus the supply of natural glycerol. Fluctuations in SYnthetic glycerol

production for the most part reflect this demand differential. The proposed production of glycerol from

glucose would compete as "synthetic" material.

In the aerobic fermentation process, there would be a projected 50% Yield of glycerol from glucose, with

no credits for possible coproducts. In the most common synthetic glycerol process, prQRylene is processed

in five conversion steps: (1) propylene to allyl chloride; (2) allyl chloride to dichlorohydrin; (3)

dichlorohydrin to epichlorohydrin; (4) epichlorohydrin to o-monochlorohydrin: and (5) amonochlorohydrin to glycerol, using limestone.

Raw Materials Cost Comparison: For the glucose-based fermentation process, a glucose raw materials

cost of $O.075/lb of glucose, results in a total raw materials cost of $O.300/lb of glycerol, given the known

yield of the process.

For the propylene-based synthetic process, the principal raw materials costs are propylene at

$0.122/lb, chlorine at $0.203/1b, and limestone at $O.027/lb, for a total of $0.352/lb of glycerol, based on

the yields of the commercial process. The ratio of the hydrocarbon-based and bioprocess raw materials

costs is then

($0352)/($0.300) =1.17,

and when a "risk" factor of 1.3 is included, the ratio becomes

1.17/13 = 0.9.

169
Future Projections: Potential biological and process improvements could reduce the raw materials cost

for the bioprocess to $0.09/lb of glycerol. Recomparison of the costs of the hydrocarbon and bioprocess

routes gives the ratio

($0.352)/($0.09) = 3.91

and when a "risk" factor of 1.3 is included, the ratio becomes

3.91/1.30 =3.01.

The glucose fennentation process to glycerol appears to be a highly promising approach, provided all

the assumptions on yield and glucose cost are realized.

Biological and process improvements could make the glycerol bioprocess competitive with the

petrochemical process. A low-eost source of glucose would widen the competitive gap in the favor of the

bioprocess. Glucose-based glycerol should find a place in the market, provided the projected low

feedstock costs are realized. It also might qualify for special uses as "natural" glycerol because it would

be derived from biomass rather than hydrocarbons (see Figure 7.6).

3.00

3.01

2.50

2.00

Estimated

Raw

Material

Cost 1.50

Ratio

.w:"'ding

Risk Factor

1.00

-; .~

0.50

0.00

$0.05 $0.06 $0.07 $0.08 $0.09

Glucose Cost

[$Ilb]

$0.10 SO.11 $0.12 $0.13

---CIImmIy ~le -. ThoorcbcaIIy Ac:bicoIable

Figure 7.6- Estimated Raw Material Cost Ratio versus Glucose Cost, Glycerol Production

170
7.3.7Isopropanol

Bioprocess:

Microorganisms, nutrients

"

Glucose Anaerobic

fermentation

Water +

Petrochemical process:

Water,

sulfuric acid

"

Recovery,

pmification

t

Butanol,

residues

---._~ ISOPROPANOL

Propylene Catalytic

hydration

t

Butanol,

residues

--... ISOPROPANOL

Processes Compared: The proposed glucose fennentation route yields the coproducts butanol and

isopropanol, with a yield to total products of 35%, based on glucose. The product split is assumed to be

43%isopropanol and 57% butanol.

In the existing hydrocarbon-based process, propylene is hydrated, either directly, at 1500-2000 psig, or

indirectly, through isopropyl sulfate, with recycle of sulfuric acid, to isopropanol. Yield based on

propylene is about 90% by either route.

Raw Materials Cost Comparison: In the glucose fennentation process, assuming a glucose cost of

$O.075/lb,the raw materials cost is $1.25/lb of isopropanol.

In the propylene hydration process, the raw materials cost is $0.105/1b of isopropanol, based on

propylene valued at $O.135/1b. The ratio of hydrocarbon-based and bioprocess raw materials cost is

then

($0.105)/($1.25) =O.~,

and when a "risk" factor of 1.3 is included, the ratio becomes

O.~/13 = 0.06.

The bioprocess would have difficulty competing with the existing petrochemical route, primarily

because of the low yield of useful fermentation coproducts and the relatively much lower cost of the

hydrocarbon feedstocks. Any RD&D effort must address these yield differences between the two routes.

171
Future Projections: Potential biological and process improvements could reduce the raw materials cost

for the bioprocess to $0.239/lb of isopropanol. Recomparison of the costs of the hydrocarbon and

bioprocess routes gives the ratio

($0.105)/($0.239) = 0.44

and when a "risk" factor of 1.3 is included, the ratio becomes

0.44/1.30 =0.34.

The bioprocess still would have difficulty competing with the existing petrochemical route, primarily

because of the low yield and the relatively much lower cost of the hydrocarbon feedstocks (see Figure

7.7).

3.00

2.50

2.00

Estimated

Raw

Material

Cost 1.50

Ratio

IacIudiDg

Risk Factor

1.00

0.50

0.00

r-- _..__.••..•... .•_. .......•:..-:::.. _. .__. ._. . .•..•_. .._ _. ._ .

0.06

$0.05 $0.06 $0.07 $0.08 $0.09

Glucose Cost

[$Ilb]

$0.10 $0.11 $0.12 $0.13

---<:uncmly Acbicvable Tboc>telica11y _ble

Figure 7.7 - Estimated Raw Material Cost Ratio versus Glucose Cost, Isopropanol Production

172
7.3.8Malic Acid

Bioprocess:

Sulfuric

acid

"

Glucose Anaerobic ... Neutralization/

fermentation filtration

t

Water Calcium Calcium

carbonate sulfate

Petrochemical process:

•IRecovery, I • MAUe purification ACID

t

Fumaric,

succinic

acids

Water

Maleic

anhydrid-e--~~

Water

Maleic

acid

hydration

Recovery,

purification ... MAUC

ACID

Processes Compared: In the glucose fennentation process, there is coproduction of malic, succinic and

fumaric acids. For this appraisal an overall yield of 75%, glucose to malic acid, was used, with an 85%

recovery efficiency.

In the hydrocarbon-based route, malic acid is manufactured in a two-step process: (1) hydration of

maleic anhydride to maleic acid, and (2) addition of another mole of water to produce malic acid. The

sole US. manufacturer is Alberta Gas, with an annual capacity of 10,000,000pounds to supply specialty

uses in the pharmaceutical industry. The potential utility of malic acid as a commodity is currently

unclear.

Raw Materials Cost Comparison: In the bioprocess, the raw materials cost is $O.268/lb of malic acid,

based on a glucose cost of $0.075/Ib.

In the hydrocarbon-based process, net raw materials cost is $0.269/lb of malic acid. The ratio of raw

materials cost is then

($0.269)/($0.268) =1.00

and when a "risk" factor of 13 is added, the ratio becomes

0.77/1.3 =0.77.

The bioprocess would have difficulty competing with the existing petrochemical route, primarily

because of the low yield of useful fermentation coproducts and the relatively much lower cost of the

hydrocarbon feedstocks. Any RD&:D effort must address these yield differences between the two routes.

173
Future Projections: Potential biological and process improvements could reduce the raw materials cost

for the bioprocess to $O.081/lb of malic acid . Recomparison of the costs of the hydrocarbon and

bioprocess routes gives the ratio

($0.269)/($0.081) = 3.32

and when a "risk" factor of 1.3 is included, the ratio becomes

3.32/1.30 =255.

The malic acid bioprocess looks favorable compared to the petrochemical process based on the raw

material cost comparison alone. The future of a malic acid bioprocess is dependent on the development

of markets for its use as a precursor to other value-added intermediates and end products (see Figure

7.8).

3.00

-,

2.50 .....

. ..

.-.

2.00

Estimated

Raw

Material

Cost I.SO

Ratio

IDcIudiIIg

IWkFactor

1.00

O.SO

0.00

.. ..- ..... ..

-.._-....

"'- "'"

-'-"--..

SO.05 $0.06 $0.07 SO.08 $0.09

Glucose Cost

[$IIb]

$0.10 SO.II $0.12 $0.13

---Cun=lIy AdUevabIe ..- -- - - . 'I"boo<eIically AdUevabIe

Figure 7.8 - Est:iJriated Raw Material Cost Ratio versus Glucose Cost, Malic Acid Production

174
7.3.9 Polyhydroxybutyric Acid

Bioprocess:

Glucose Anaerobi~ Neutralization!

fermentation filtration

Maleic I . l-Butyrolactone anhydride~ Hydrogenation hydrolysis

MiQOOrganifS, nutrients

Water Calcium

carbonate

Petrochemical process:

Hydrogen

t

Sulfuric

acid

t

Calcium

sulfate

Water

t

t

Residue

Recovery,

purification

t

Residue

• "(-HYDROXYBUTYRIC ACID

y-HYDROXYBUTYRIC ACID

Processes Compared: To simplify this comparison, and to make best use of available literature

information, the comparison is based on the monomer y-hydroxybutyric acid. This is a specialty

chemical produced in limited quantities and used for plasticizer and pharmaceutical precursor

applications.

In the bioprocess, a glucose fermentation with an overall Yield of 40% is assumed, based on limited

process infonnation. .

In the hydrocarbon-based process, developed and used by 10, maleic anhydride is first hydrogenated

to -y-butyrolactone. The lactone then is hydrolyzed to -y-hydroxybutyric acid. There is a 90% Yield in

each step.

Raw Materials Cost Comparison: In the bioprocess, the raw materials cost, based on the process Yields

and an assumed glucose cost of $0.075lIb, is $0375lIb of -y-hydroxybutyric acid.

In the ICI process, the total raw materials cost is $O.340/Ib of y-hydroxybutyric acid, using a raw

materials cost, previously described, of $0.269lib of n-butane derived maleic anhydride. The raw

materials cost ratio is then

($0.340>/($0.375) = 0.91

and when a "risk" factor of 1.3 is added, the ratio is

0.91/1.3 =0.70.

175
Future Projections: Potential biological and process improvements could reduce the raw materials cost

for the bioprocess to $O.l68/lb of 'Y-hydroxybutyric acid. Recomparison of the costs of the hydrocarbon

and bioprocess routes gives the ratio

($0.340)/($0.168) = 2.02

and when a ''risk'' factor of 1.3 is included, the ratio becomes

2.02/1.30 =1.56.

The biomass-based process hasthe potential to compete with existing processes, if RD&D can improve

the performance of the bioprocess (see Figure7.9).

3.00 +--"----+--'--+----'--f--...J..--r------'---+--"'---!----'--+----''----+

2.50

.........

2.00

Estimated

Raw

Material

Cost 1.50

Ratio

IDdDdiDg

Risk F8Ctor

.....

..........

<; -. ~.

<; 1.56

-•..

"-"-

-..- _- 1.00

0.50

0.00

..-.-.. ..-..--.. "'- ......... ...

$0.05 $0.06 $0.07 $0.08 $0.09

GlucoseCost

[$/lb]

$0.10 $0.11 $0.12 $0.13

---CI>r1emIy ~Ie --- --.-•••...••-- Tboorcti<a1Iy Ac:mc.able

Figure 7.9 - Estimated Raw Material Cost Ratio versus Glucose Cost,. Polyhydroxybutyric Acid

Production

176
7.3.10 Propionic Acid

Bioprocess:

,c;O, .

Anaerobic

Glucose fermentation

Water .Calcium

carbonate

Petrochemical process:

Sulfuric

acid

Neutralization/

filtration

t

Calcium

sulfate

Recovery, • .~ PROPIONIC

purification ACID

t

Acetic acid,

residue

Ethylene --•.-~ ICarbonylationI PROPIONIC

ACID

ProcessesCompared: The bioprocess is an anaerobic fennentation of glucose, using limestone to control

pH and sulfuric acid for neutralization. Overall yield from glucose is 60% to mixed propionic and acetic

acids, with a 2:1 ratio of propionic to acetic. Coproduct acetic acid is assumed to share costs.

The hydrocarbon-based process starts with the hydrofonnylation of ethylene to propionaldehyde,

which is then oxidized to propionic acid. Almost 90% of the domestic propionaldehyde supply is

produced by this process, principally by Tennessee-Eastman and Union Carbide. The overall yield,

based on ethylene, is 90%. Total existing capacity is 225,000,000 pounds per year.

Raw Materials Cost Comparison: In the bioprocess, the raw materials cost is SO.326/lb of propionic

acid. In the hydrocarbon-based process, the total raw materials cost is SO.200/lb of propionic acid,

based on an ethylene raw materials cost of SO.225/Ib of ethylene, which is a current average value

between atmospheric gas oil and naphtha feedstocks. The ratio of raw materials costs is then

($0.200)/($0326) =0.61,

and when a "risk" factor of 1.3 is added, the ratio becomes

0.61/1.3 =0.47.

177
Future Projections: Potential biological and process improvements could reduce the raw materials cost

for the bioprocess to SO.l44/lb of propionic acid. Recomparison of the costs of the hydrocarbon and

bioprocess routes gives the ratio

($0.200)/($0.144) = 139

and when a "risk" factor of 1.3 is included, the ratio becomes

139/1.30 = 1.0'7.

The biomass-based process has the potential to compete with existing processes if RD&D can improve

the performance of the bioprocess (see Figure 7.10). Propionic acid is not a large-scale commodity, and

opportunities for investment in new capacity will be limited.

3.00

2.50

2.00

Estimated

Raw

Material

Cost 1.50

Ratio

IacladiDg

Risk Factor

1.00

-c. ,

...... 1.07 .

.•......

.........._.._ __.•..•._-_ " .•,

0.50 ~~;--------1 0.47

0.00

$0.05 $0.06 $0.07 $0.08 $0.09 $0.10 $0.11 $0.12 $0.13

Glucose Cost

[$/Ib]

---Cun=lIy ..•.•._ _........•..•. Tboot-c<ic:a1Iy ~lc

Figure 7.10- Estimated Raw Material Cost Ratio versus Glucose Cost, Propionic Acid Production

178
7.3.11Propylene Glycol

Bioprocess:

Microorganisms, nutrients

"

Glucose Anaerobic

fermentation

Water +

Recovery,

purification

,

Butanol,

residues

Petrochemical process:

. . :~

4 Propylene

PROPYLENE

GLYCOL

Propylene

oxide

hydrolysis

_ ........ t-Butyl

hydroperoxide ~~..._ ..

Catalytic

oxidation

t-Butyl Recovery,

alcohol purification

Processes Compared: In the fermentation of glucose, the best reported experimental yield is 27%, based

on glucose; the theoretical yield is 42%. For this evaluation, 35% yield was used.

In the hydrocarbon-based route, propylene oxide is hydrated in 85% yield to propylene glycol.

Propylene oxide is coproduced with t-butyl alcohol in a two-step process consisting of: (1) oxidation of

isobutane to t-butyl hydroperoxide and t-butyl alcohol, and (2) reaction of Propylene with t-butyl

hydroperoxide to yield the coproducts, propylene oxide and t-butyl alcohol. The propylene oxide yield

is about 93%of theoretical, and 0.71unit of propylene is consumed per unit of propylene oxide.

Raw Materials Cost Comparison: In the fermentation Process, the raw materials cost is $0.556/lb of

propylene glycol, based on a glucose cost of $0.075lib of glucose.

In the propylene-based process, the raw materials cost is $0.285/lb of propylene glycol, based on

propylene valued at $O.135/lb. The ratio of raw materials costs is then

($O.285)/(SO.556) = 0.51,

and when a "risk" factor of 1.3 is included, the ratio becomes

0.76/13 =039.

The bioprocess would have difficulty competing with the existing petrochemical route, primarily

because of the low yield of useful fermentation coproducts and the relatively much lower costof the

hydrocarbon feedstocks. Any RD&D effort must address these yield differences between the two routes.

179
Future Projections: Potential biological and process improvements could reduce the raw materials cost

for the bioprocess to $0.188/1b of propionic acid. Recomparison of the costs of the hydrocarbon and

bioprocess routes gives the ratio

($0.285)/($0.188) = 152

and when a "risk" factor of 1.3 is included, the ratio becomes

152/130 =1.17.

The bioprocess has a possibility of competing with existing processes if RD&:D can improve the

performance of the bioprocess (see Figure 7.11).

3.00

2.50

2.00

Eaaated

Raw Material .

Cost 1.50

Ratio

IDdudiag

Risk Factor

1.00

- - ...... ......-... 1.17

.__ _-----_. ........ - - . . . ...•.........

t

0.00

$0.05 $0.06 $0.07 $0.08 $0.09

Glucose Cost

[$JIb]

$0.10 $0.11 $0.12 $0.13

---Cur=tly AcbilowhIe -.--- It.c:bilOv3l>Ie

Figure 7.11-Estimated Raw Material CostRatio versus Glucose Cost,.Propylene Glycol Production

180
7.3.12Succinic Acid

Bioprocess:

Sulfuric

Micromgalms, nutrients acid

,~

Glucose Anaerobic Neutralization! Recovery, SUCCINIC

fermentation filtration purification ACID

, ,

Water Calcium Calcium Acetic

.carbonate sulfate acid

Petrochemical process:

Water

IHY!\Y53 I Maleic Maleic

.. Recovery, SUCCINIC

anhydride acid .-

hydrogenation purification ACID

,

Residue

Processes Compared: The bioprocess is an anaerobic fermentation in the presence of hydrated lime,

with intermediate calcium succinate recovered by acidification with sulfuric acid, and succinic acid

recovered as a water solution. Major raw materials are glucose, limestone, and sulfuric acid. Minor raw

materials are carbon dioxide, ion exchange resins, nutrients, com steep liquor, tryptophan, and sodium

carbonate. The fermentation yield is reported as 87% to calcium succinate; recovery yield is assumed to

be 80%.

In the hydrocarbon-based process, n-butane is first oxidized to maleic anhydride. This wellestablished process is used by five U.S. companies, four in Western Europe, and two in Japan. Reliable

manufacturing cost data is reported in the SRI Chemical Economics Handbook. Maleic anhydride is

then hydrated to maleic acid, and in a second step the double bond is hydrogenated to yield succinic

acid. Overall yield of maleic anhydride to succinic acid is 95%.

Raw Materials Cost Comparison: In the bioprocess, the raw materials cost is $0.187/Ib of succinic acid.

In the hydrocarbon-based process, total raw materials cost is $0.269/lb of succinic acid. The ratio of

raw materials costs is then

($0.269)/($0.172) = 1.56,

and when a "risk" factor of 1.3 is added, the ratio becomes

1.56/1.3 = 1.20.

181
Future Projections: Potential biological and process improvements could reduce the raw materials cost

for the bioprocess to SO.081/1b of succinic acid. Recomparison of the costs of the hydrocarbon and

bioprocess routes gives the ratio

($0.269)/($0.081) = 3.32

and when a "risk" factor of 1.3 is included, the ratio becomes

3.32/1.30 = 2.55.

The succinic acid bioprocess looks favorable compared to the petrochemical process based on the raw

material cost comparison alone. The future of a. succinic acid bioprocess is dependent on the

development of markets for its use in food products and as a precursor to other value-added

intermediates and end products (see Figure 7.1~).

3.00

2.50

2.00

Estimated

Raw

Material

Cost 1.50

Ratio

IDdudiDg

J.lisk Flldor

1.00

0.50

0.00

......... 2 c • ...... . N

... ".< ,

< ,

...... ......

..-.....

j .-....

-+

SO.05 $0.06 $0.07 SO.08 $0.09

Glucose Cost

($Ilb]

$0.10 $0.11 $0.12 $0.13

---CunaIlly AclDevablo .._._._._. .........•_. AdUcYal>Io

Figure 7.12- Estimated Raw Material Cost Ratio versus Glucose Cost, Succinic Acid Production

182
7.4 Qualitative Influences

The qualitative influences considered in the selection of the first two candidates for the integrated

product/process screening are listed under four broad categories. The current set of influences are:

•

•

•

•

Energy Impacts

Process energy savings

Vulnerability to oil supply disruptions

Feedstock displacement

Environmental Quality

Air emissions

Water pollution

Solid waste generation

Regulatory impacts

Cost of Remediation

Economic Competitiveness

Current cost of production

Future cost of production

Current market price

Future market price

Consumer interest

Probability of Success

Potential domestic production

...

l

Each of the candidates is assessed with respect to the criteria listed above. The current assessment is

given in two parts as Table 7.6. The nomenclature for this table is as follows:

+ favorable impact

unfavorable impact

o little or no impact

blank unable to assess impact at this time

183
Table 7.6, part I - Qualitiative Influences on Selection Process

Energy

Imnaets

Environmental

Qualitv

Economic

Com netldveness

Probability

of Success

o

...

+

+

+

+

+

o

o

o

+

+

+

+

o

o

+

+

+

+

o

o

+

o

+

+

o

o

+

o

+

+

+

+

o

+

o

o

o

o

o

o

o

o

+

+

+

o

+

o

o

o

o

o

o

o

+ Acetaldehyde

+ Acetic Acid

+ Acetone

+ Acrylic Acid

+ AdipicAcid

Alginate

Ascorbic Acid

Azelaic Acid

o

o

+

+

o

o

o

o

o

o

o

o

o

+

+

o

o

o

o

o

o

o

+

+

o

o

o

o

o

o

+

+

o

o

o

o

+

o

o

o

+

o

+

:f. -- .-.... ,- J.

+

o

o

o

o

o

o

o

o

o

o

o

o

o

o

+

+

o

+

+

o

o

+

o

o

o

+

o

o

o

+

+

+

+

+

+

+

+

+

+

o

+

+

o

o

o

+ BacterialCellulose

Butanediol, 2,3-

+ Butanol

ButyraJdehyde

Butyric Acid

Cellulase

+ CitricAcid

Dextran

Fumaric Acid

Gluconic Acid

Glycerol

+ Hyaluronic Acid
·'·• •·,· -, 1

Table 7.6, part 2 - Qualitiative Influences on Selection Process

Energy Environmental Economic Probability

Imr acts Qualitv Com petitiveness of Success

t < o S' ~"Tl fr

"r1 (") a

f ii ~~ i m

"Tl !. d' il !~ ! I I "1j

I ..... n i §R ~. (JQ W lit! 8'

& g. f o o a. a. 0

a~ (; e. a. 0

g 8 tr.

g

+ + 0 0 + 0 0 Isopropanol

0 0 0 Itaconic Acid

+ 0 + + + + + 0 + + + LacticAcid

0 0 + + + + 0 + 0 + Lysine

0 0 0 + 0 MalicAcid

0 0 0 0 0 0 0 OleicAcid

. + 0 + + + 0 + 0 + Polyhydroxybutyric Acid

0 0 0 0 0 + 0 Propanediol, 1.3-

+ 0 0 + 0 0 0 0 Propionic Acid

+ + + 0 + + 0 0 + 0 + Propylene Glycol

Protease

0 0 0 + + 0 + 0 + Pullulan

0 0 0 Rhamsan Gum

+ 0 + 0 Scleroglucan

0 0 0 0 0 0 0 0 0 0 0 Sorbitol

+ + + 0 + + + + 0 + + + Succinic Acid

0 0 0 + . + 0 0 0 0 Surfactin

0 0 0 0 0 0 0 TartaricAcid

+ 0 + 0 0 0 0 + 0 + 0 Xanthan Gum

0 0 0 XylitoJ

185
'1.5 Initial Candidates for Process Evaluation

The methodology described above led to the selection of initial target candidates for more detailed

evaluation. Each of these specific targets, an industrial chemical, is also representative of a product

family to allow a potential greater developmental impact while focusing on commercializing a specific

chemical process. The continuing, iterative RD&D will require reevaluation as new information is

discovered; this will influence future targets and help to place current targets in order of priority. This

approach also will provide a framework for future decision points while allowing commercialization

to take advantage of current opportunities. Generic process flowsheets were created as a tool for

identifying potential areas where cross-eutting advanced technologies and genetic techniques can have

an impact. For example, in feed material processing, fractionation and hydrolysis are two key

processes in the conversion of lignoceUulosics. The.initial feedstocks are starch from corn grain and

cellulose from wood.

'1.5.1 Organic Acids (SuccinidMalicIFumarid

Many industrial organic acids, such as acetic, citric, and lactic acids, can be produced by fermentation.

Gtric acid is made by fennentation, new processes are being developed and plants are being built for

lactic acid, and acetic acid is still produced by fermentation for food use (vinegar). Another group of

organic acids includes succinic, malic, and fumaric acids, which are four-earbon dicarboxylic acids that

are interconvertable chemically or enzymatically. Microbially, these acids are often produced by

similar metabolic pathways and often as by-products. They have ultimate uses in manufacturing

polymers, resins, antioxidants, and other commercial products described below.

'1.5.1.1 Market Definition

Succinic acid (SA) and succinic anhydride (SAH) currently are produced from petrochemical

feedstocks, as are all of the prospective derivatives of these two chemicals (see Table 7.7). Most or all

commercial production of SAand SAHis non-domestic.

The production levels for SA and SAH are low at present, but the industry is stable. If the proposed

derivatives (which include 1,4-butanediol, gamma-butyrolactone, tetrahydrofuran, and adipic acid)

were to be produced using succinic acid as a feedstock chemical (in place of the'currently used feedstock

chemicals), the market demand would rise dramatically. For example, if 50% of current 1,4-butanediol

production was based on a succinic acid feedstock, the market demand for succinic acid would increase

approximately 2~fold, i.e., from 0.00045 million metric tons/year (0.001 billion lbs/year) to 0.09

million metric tons/year (0.2billion lbs/year). Because all of the proposed derivatives are commodity

chemicals, this reasoning can be applied to all examples of potential displacement by succinic acid, i.e.

a change to a succinic acid feedstock for the production of gamma-butyrolactone, tetrahydrofuran, or

adipic acid will substantially increase succinic acid market demand. An important consideration in

proposing such a scale-up of market demand is that the market price should become significantly lower.

The markets for the materials produced from the proposed derivatives, i.e., polybutylene

terephthalate (PBT) resins (used for automotive and electrical parts), polyvinyl chloride (PVC, used

for many plastics applications), and nylon, are all stable and are expected to continue to grow

(Chemical Marketing Reporter, 1990-1992).

Of interest is the historical tightness of the adipic acid and 1,4-butanediol markets in recent yea:--:;

that has resulted in increased imports of these chemicals. This market tightness indicates a need f

increased Ll.S. production capacity, which may encourage development of a new synthes .

methodology, i.e., utilization of a succinic acid feedstock.

186
Table 7.7 • Market Information for Succinic Acid/Succinic Anhydride and Potential Derivatives.'

Chemical Growth! Production] Price' Price Usage" Feedstock?

Stability'

Succinic Acid S 0.00045 957 (435) + Multiuse" Succinic Anhydride

(SA) (0.001)8

Succinic Anhydride S 0.00045 376 (171) + Multiuse" Maleic Anhydride

(SAH) (0.001)8

1A-Butanediol S (3.5) 0.2 (0.45) 220 (100) + Feedstock for tetrahydrofuran, PBT Acetylene. Fonnaldehyde

resins, and gamma-butyrolactone

Gamma- S - 301 (137) + Feedstock for pyrrolidone Tetrahydrofuran or

Butyrolactone derivatives 1A-Butanediol

Tetrahydrofuran S - 282 (128) + Feedstock and solvent for polymers 1A-Butanediol

including PVC and PTMEG

Adipic Acid S (2.5) 0.77 (1.7) 145 (66) + Feedstock for nylon and nylon Cyclohexane or phenol

resins

'Sourees of informationare: Chemical Marlce,ing Reporter 1990-1992;Encyclopedja 01CMmical Technology 1982; Szmant 1989.

'predicted growth of industry over next two to four Ye.1rs. (S) indicates stable growth predicted. Numerals indicate predicted percentage growth increase!Ye.1r.

'Current annual production for United Slates, metric tons x 10'/yr (billion Iblrr). (-) indicates current production not known at this time.

4Current market price, bulk quantities, ¢lkg(¢lIb).

5(+) indicates that the market price has remained stable over the list 1.5 years.

5Current primary utilization for chemical.

7Current petrochemical feedstocks used to produce chemlca],

'Current combined total production of SAH and SA for world.

'SA and SAH are currently used in unmodified and derivauzed forms as additives for several industries includingpharmaceuticals, food, and cosmetics.

187
': .....

. .

Another important consideration is the relatively innocuous nature of succinic acid when compared to

the other chemical feedstocks listed in Table 7.7. Minimization of hazardous waste generation in any

prospective chemical process is imperative in the designing stage of that process, primarily because it

improves the process economics (Stavins and Whitehead, 1992; Russell et aI., 1992).

Domestic producers of derivatives include Allied Signal (adipic acid), Arco (l,4-butanediol), BASF

(l,4-butanediol), DuPont (adipic acid, 1,4-butanedion, ISP (1,4-butanediol), and Monsanto (adipic

acid) (Chemical Marketing Reporter, 1990-1991). There are thirteen domestic producers of PVC:

Borden, CertainTeed, Formosa, Georgia-Gulf, Goodrich BF, Goodyear, Keysor-Century, OxyChem,

Shintech, Union Carbide, Vista, Vygen, and Westlake (Chemical Marketing Reporter, 1992).

7.5.1.2Process Evaluation

7.5.1.2.1 Process Concept

The base-case process concept for the bioproduction of succinic acid (Datta 1991) is illustrated in

Figure 7.13. The process is modeled as a continuous operation and is sized at a scale equivalent to

processing all of the hydrolyzed starch from a 15,000 bushel/day com wet-milling plant. The

productivity and yield data used in this design were translated from batch- and small-scale continuous

fermentation data.

Glucose syrup is the feedstock used in the proposed process. This feedstock is diluted with process

water and a recycle stream from the product recovery operations and is sterilized in a steam injection

sterilizer. The glucose concentration of the feed stream leaving the sterilizer is slightly greater than

50 g/L, Com steep liquor and the additional required nutrients and salts are batched and sterilized

separately and then continuously combined with the glucose feed stream prior to its addition to the

fermentor. A portion of the feed stream is diverted to the seedtrain as required for inoculum growth for

the production fennentors.

A sterile calcium hydroxide slurry is added to the fermentors on demand for pH control. The addition

of the calcium hydroxide simultaneously neutralizes the fermentor broth and precipitates the succinate

as calcium succinate. An overall fermentor productivity of 2.0 g/L-h was used to size the production

fermentors. The yield of succinate on glucose was assumed to be 0.88gram of succinate produced per gram

of glucose consumed. Nine 150,000 gal fermentors in series are required to complete the fermentation;

i.e., the glucose concentration leaving the final fermentor is less than 0.1% « 1.0 g/L).

The calcium succinate is recovered from the fermentor broth by first concentrating the slurry using ,

hydrocyclones, then pressing the slurry in two belt press filters in series. A wash step is included j

between the belt press filters. The cake from the second filter is rewashed and the slurry is acidified to

convert the calcium succinate to succinic acid and insoluble calcium sulfate (gypsum), which

precipitates. Concentrated sulfuric acid is used for this acidification process. The succinic acid I calcium

sulfate slurry is neutralized in a subsequent vessel using sodium hydroxide as the base. The calcium

sulfate is recovered in another series of two belt press filters, again with a wash step after each press.

The calcium sulfate slurry is fed to a screw press to remove most of the water. Part of the pressate from

the screw press is sent to waste treatment and the rest is recycled to the front of the process.

The filtrate from the belt press filters containing the succinic acid is sent through a series of ion

exchangers. The first is a strongly acidic cation exchanger, which removes the calcium and other cation

impurities. The second is a weakly basic anion exchanger, which removes the sulfate and other strong

anionic contaminants. The highly purified succinic acid is concentrated in a multi-effect evaporator to

give a product stream that is approximately 50% succinic acid. A plant this size could produce

approximately 150 million pounds of succinic acid annually. This base-case process for the

bioproduction of succinic acid is intended to show the economic potential with existing technology.

Multiple improvements and modifications are intended and are described in sections 7.5.1.3 and 7.5.1.4.

188
Recycle Waste Treatment

" Succinate Salt - - - Sterilization - Fermentation -- - Recovery - Feed

d

" " Inoculum Acidification Build-Up

,r

Neutralization

Utility Systems:

Cooling Water "

Fermentation Gas Succinic Acid

Gypsum to disposal -- Recovery -- -- Process Water

PlantlInstrument Air

CIP/CS System ,r

Process Steam

Impurities to waste -:::

lon-Exchange

Waste Treatment - Purification - Concentration

Concentrated Succinic Acid ......... ----------------------

Figure 7.13 - Base Case Process Concept for Biopmduction of Succinic Acid

189
7.5.1.2.2 Profitability Analysis

The first step in completing the profitability analysis was to estimate the cost of the purchased

equipment Most of the equipment was assumed to be Constructed of stainless steel; however, some of the

equipment was costed assuming it was constructed from carbon steel, and some had specialized

materials of construction factors applied to the stainless steel construction cost. An equipment schedule

spreadsheet was created with links to the key flow rates used to size each of the major pieces of

equipment in the material balance spreadsheet. The cost of the equipment was estimated for the basecase plant size using historical data updated to the reference year (1992). These data were combined

with individual cost exponent factors for each type of equipment and the linked process flow rates to

determine the purchased equipment cost for plants smaller and larger than the base-case plant size.

Once the purchased equipment price was estimated, the factoring method was used to estimate the

costs of shipping, piping, electrical, instrumentation, foundations, insulation, and so on. The total

installed purchased equipment price for the base case was estimated to be $15,000,000 from an

estimated purchased equipment price of $6,600,000.

The total fixed capital investment was determined, again using a factoring method, from the installed

purchased equipment cost. Examples of items included in the total fixed capital investment include

land, yard improvements, service facilities, engineering and supervision, contractor's fee, and

contingency. The total fixed capital investment for the plant was determined to be $27,400,000.

The annual costs of raw materials and utilities was determined from the material and energy balances.

A stream factor of 0.9 was used to calculate these costs. Table 7.8 summarizes the unit costs used in the

analysis.

Table 7.8· Unit Raw Material Costs

Glucose Syrup, 95DE

Corn Steep liquor

Calcium Hydroxide

Sulfuric Acid, 100%

Carbon Dioxide, liquid, 995% purity

Tryptophan

Cysteine HCI

Sodium Hydroxide

Hydrochloric Acid

Sodium Carbonate

Cation Resin, Dowex 50 WX8

Anion Resin, Amberlite IRA-94, Rohm & Hass

Source of Estimate

ANt, NREL Estimate

ANt, NREL Estimate

CMR, 1/7/91

CMR, 1/7/91

Air Products

ANt Estimate

NREL Estimate

CMR, 1/7/91

CMR, 1/7/91

CMR, 1/7/91

Dow Chemical

NREL Estimate

Cost (s!lb1

0.0750

0.0250

0.0260

0.0430

0.0400

10.9000

3.2000

0.1130

0.0350

0.1960

30.4000

30.0000

The unit costs of the utilities are given in Table 7.9, and are all ANL, NREL estimates.

Item

Steam, 50 psig, [klb]

Electricity, [kWh]

Cooling Water, [klb]

Process Water, [klb]

Waste Treatment, [klb]

Solid Waste Disposal, [ton]

Table 7.9 • Unit Utility Costs

Unit Cost [$/unit listed]

2.000

0.045

0.012

0.042

0511

20.000

190
The operating labor costs were determined using estimates of man-hours required per unit operation per

shift. The total annual operating labor costs were determined to be $1,200,000. Labor-related expenses

such as supervisory labor, payroll overhead, and laboratory charges were estimated as percentages of

the operating labor. These total labor-related costs were estimated to be $800,000 annually.

Capital-related costs were estimated as percentages of total plant cost. These costs include items such

as maintenance, operating supplies, local taxes and insurance, and plant overhead costs. The capitalrelated costs were estimated to be $2,100,000 annually.

Finally, costs indexed to sales, such as packaging and storage, administrative costs, distribution and

sales, and RD&D, were estimated as percentages of total sales. The sales-related. costs were estimated

to be $1,000,000 annually.

The discounted-cash-flow method was applied to determine the product selling price necessary to

satisfy all the constraints. The product selling price for the base-case design was determined to be

$O.354/lb of succinic acid. This corresponds to a production level of approximately 150 million pounds

per year. A lower net selling price is expected when process improvements described in .the next two

sections are incorporated into the process design.

The manufacturing cost summary for the base-case design is given in Table 7.10.

191
Table 7.10 - Manufacturing Cost Summary, Succinic Acid from Glucose Symp

Succinic Acid Production from Glucose Syrup; Basis =15000 bulday Com Wet-Milling Plant

Loc:ation Midwest AllDual Capacity 153.300,000 Ibssucc:iDic acid

EffectiveDate to Which Estimate Applies Oct-91 Cost Index Type CE Plant Index

Predicted SeUingPrice: $0.354 Cost IDdex Value 357.7

Fued CapiCal $27,400,000

Workin& CapiCal $5,800,000 Total Capital Investmeat $33,200,000

Assumptions I

Plant Life 10 years InvestmentTax Credit. First Year 0.0%

DCF R.ate-ofRetum IS.I)OO!o Woridng Capital. (determined independeutly) N/A

Equivalent Return on Inveslment 27.18"10 Assumed Inflation Rate 3.5%

Equipment Service Life, MACRS Depm:iation 5 years PercentofTotal FixedCap1ta1lnvestmentSpentin Year-3 30.0%

Building Service Life. Slraigbt·Linc Dcprec:iation 30 years Percent ofTotal FixedCapital Investment Spent in Year -2 50.0%

Combined Federal and StateTax Rate 37.0% Percent of Total FixedCapital Investment Spent in Year-l 20.0%

Equipment Salvage Value 0.0% Percent ofStart-Up CostsSpent in Year -! 30.00!o

Production Cost I 5peryr 5 perIb product

Raw Materials, (itemized on page 3) $27,900,000 SO.182

By-Product CreditS SO SO.OOO

Utilities. (itemized on page:: 3) S10,100,OOO SO.066

Ion ExchangeResins $500,000 SO.003

Operating Labor SI,200,OOO SO.008

Labor Relatcd Costs $800,000 SO.005

Capital Related Costs $2,200,000 SO.014

Sales Relatcd Costs S1,100,OOO SO.007

Total Expense at 100·/. Capacity, proof year: 5 543,300,000 $0.282

Revenue I

Revenue from Sales 554,300,000 SO.354

Net ADDual Profit S11,OOO,OOO SO.072

AnDuallDcome after Taxes 57.900,000 50.052

Raw Material Costs I 5 perIb raw material

Glucose:: Syrup 95 DE ANI., NREL Estimate 50.0750

Com Steep Liquor 50 % Solids ANI., NREL Estimate $0.0250

Calcium Hydroxide CMR. 12/25192 SO.0260

Sulfuric Acid 100% CMR, 12125192 SO.0430

Carbon Dioxide liquid.. 99.5% purity AirProducts SO.0400

Tryptophan ANL Estimate SI0.9000

Cysteine HCI NREL Estimate 53.2000

Sodiwn Hydroxide CMR,lnt91 50.1130

Hydrochloric Acid CMR,lnl91 50.0350

Sodium Carbona1e CMR,lnl91 50.1960

Calion Resin Dowe::x SO WX 8, Dow ChemiC<'l DowChemical $30.4000

Anion Resin AmberliteIRA-94, Rohm & Haas NREL Estima1e 530.0000

192
..

Manufacturing Cost Summary continued

Succinic Acid Production from Glucose Syrup; Basis = 15000 buJday Com Wet-Milling Plant

Labor I

8 Operators pershift@ SIS per br

21 shiftsper week per position 1.5Overtime Multiplier

3 weeks va.e:ationper operator

Total Operating Labor 51,200,000 / year 5

Labor Related Costs I Percentage ofOperating Labor

Payroll Overhead 32.50% $400,000

Supervisory & Miscellaneous Labor 25.00% S300,OOO

Laboratory Charges 10.00% S100,000

Total Labor Related Costs 5800,000 /year 5

Capital Related Costs I Percentage ofPlant Cost

Maintenance 1.50% S500,000

Operating Supplies 1.50% $400,000

Environmental 1.50% $400,000

Local Taxes 1.00% $300,000

Insurance 0.50% SI00,OOO

Plant Overhead Costs 1.50% $400,000

Total Capital Related Costs S2,100,OOO /year 5

Sales Related Costs I Percentage ofAnnualSales

Pateots & Royalties 0.00% SO

Packaging & Storage 0.25% S100,OOO

Administrative Costs 1.00% S500,000

Distribution & Sales 0.25% S100,000

Research & Development 0.50% $300,000

Total Sales Related Costs S1.000,000 /year 5

Equipment I Percentage ofPurcbased Equipment Cost

Purcbascd Equipment Cost $6,600,000

Shipping 5.0% S300,000

Piping 40.0% S2,700,000

Electrical 10.00Al S700,000

lnstJumentation 30.00Al S2,000,000

Utilities andService Facilities ISBL 15.0% SI,OOO,OOO

Foundations 7.5% S500,000

Insulation 5.0% S300,OOO

Painting 5.0% S300,OOO

InstaUation 10.0% $700,000

Total Purchased Equipment Installed SI5,100,000

Fixed Capital I Pertentage of Fixed Capitallnvestment

Yard Improvements 1.0% $300,000

Utilities and Service Facilities OSBL 7.5% $2,100,000

Land 0.5% $100.000

Engineering and Supervision 7.5% $2.100,000

Construction Expenses 5.0% $1.400,000

Contractor's Fee 3.5% $1.000,000

Contingency 10.0% $2,700,000

Buildings 2.5% $700.000

Start-Up Costs 7.5% S2.100,000

Total Fixed Capital Investment 527.400.000

193
Manufacturing Cost Summary continued

Succinic Acid Production from Glucose Syrup; Basis = 15000 bulday Com Wet-Milling Plant

Raw Material Costs 1Mb IIIc:dlliC acid 5 peryr 5 perIb procluct

GI~Syrup 9SDE 1.13 S13,OOO,OOO $O.084S lib product

Com Steep Liquor SO % Solids 0.20 $800,000 $O.OOSO

Calcium Hydroxide 0.70 $2,800,000 $0.0183

Sulfuric Acid 100% 0.91 16,000,000 SO.0393

Carbon Dioxide liquid, 99.SO/.purity 0.18 S1,1OO,OOO $0 .0071

Tryptophan 0.001 S1,7oo,OOO $0.0108

CysteineHCI 0.002 SI,200,Ooo $0.0079

Sodium Hydroxide 0.02 $400,000 $0.0028

Hydrochloric Acid 0.02 Sloo,OOO $0.0008

Sodium Carbonate 0.01 $300,000 $0.0019

50.1785 lib product

~:':; . . :~ Ion-Exchange Resins ,".( 'h)' 1

Cation Resin Dowex SO WX8, Dow Chemical $300,000 $0.0018 lib product

Anion Resin Amberlite 1RA·94, Rolun&. Haas $300,000 $0.0018

SO.OO35 lib product

Utilities

Steam, SOpsig@ S2/1000 Ib 11.546 $3,500,000 $0.0228 lib product

Electricity@ $O.04S IkW-br $300,000 SO.0020

Cooling Water@ $0.012/1000 Ib 207.20S S4OO,ooo SO.0026

Precess Water@ $0.042/1000 Ib 11.0S0 Sloo,OOO SO.0007

Waste TRabDeat@ SO.SI1 11000Ib 13.123 Sl,Ooo,OOO SO.0065

Solid Waste Disposal @ $201ton 3.163 $4,800,000 SO.0316

So.0662 lib product

Cost Contributions

RawMaterials:

Utilities:

Operaling Labor:

Labor RelatedCosts:

Capital RelatedCosts:

Sales RelatedCosts:

Capital Equipment:

Taxes:

Interest onInvestment:

Return onInvestment:

Total:

% ofPredicted SellingPrice

SO.4%

18.7%

2.ze/o

1.5%

4.1%

2.0%

4.9%

4.3%

0.0%

12.0%

100.0%

SO.1785 lib product

SO.0662

$0.0078

$0.0052

$0 .0144

$0.0072

SO.OI72

SO.0IS1

$0.0000

$O.042S

SO.354O lIb product

• 50.4% 0 18.7% 2.2% 0 1.5% 04.1% DDl2.0% II 4.9% Iii 4.3% 00.0% § 12.0%

194
Manufacturing Cost Summary continued

Succinic Acid Production from Glucose Syrup; Basis = 15000 bulday Com Wet-Milling Plant

Design Basis I

Plant Type

Stream FadOr

Nominal~

Type

Number of Stages

NomiDal Volumeof each Stage

Initial GlucoseConcentration

Initial Com Steep Liquor Coocentralion

Overall Productivity

Overall Yield ofSuc:cinateon Glucose

Overall Yield of Acctalc on Glucose

Gas Flow Rate(carbon dioxide)

AcidUsedto RecoverSuccinicAcid

Pm:cnt ExcessAcidUsed

NeutralizingBase

PercentExcessBase Used

FractionofEftluent Recycled

LoadiDgTime of Cation Resin

Regeneraot

RegeacraliClll Time

Ratio of Flows: RegaacraliClll:Loading

LifeofResin

LoadingTime of AnionResin

Regcncrant

RegenerationTime

Ratio of Flows: Rcgcneration:Loading

LifeofResin

Concentration

Method

Rcsuhing SuccinicAcidConcentration

Total Production

Grass Roots, Nth plant

0.9

150 millionpounds of succinic acid

Continuous with Batch Finish

9

150,000 gallons

so gramsI liter

5.0 grams/ liter (dry-basis)

2.0 grams sucx:inatc / liter / hour

0.88 poundsproduced I pounds utilized

0.10 pouuds producedI pounds utilized

1 volume I volume I hour

Sulfuric Acid

10%

Calcium Hydroxide

0%

50%

24 hours

HydrocbloricAcid, 1 Molar

6 hours

0.2

2 years

24 hours

Sodium Hydroxide. 1 Molar

6 hours

0.2

2 years

Triple-EffectEvaporator

50.0%

306.6 million pounds 50% Succinic Acid

195
7.5.1.3Application of New Technologies in Genetic and MetabolicEngineering to Succinic Acid

New technological advances greatly enhance our ability to manipulate the metabolism of a variety of

organisms. The polymerase chain reaction <PeR; Amheim et al., 1990) generates large quantities of a

gene and can simultaneously introduce precise changes in the gene's DNA sequence. Consequently, it

has become much easier to manipulate genes, tailoring them for expression in different organisms or for

production of proteins with altered properties. New physical methods have arisen that permit

introduction of foreign DNA into microbes without the development of Specialized biological gene

carriers. Electroporation employs an electrostatic discharge to briefly permeablize bacteria, allowing

uptake of DNA (Dower, 1990). Particle acceleration methods literally shoot microspheres coated with

DNA into cells, and have recently been used successfully on bacteria (Klein et al., 1992; Sanford et al.,

1992). Another new approach, called antisense technology, allows the introduction of nucleic acids

antagonistic to the native nucleic acids of an organism, thereby allowing controlled alterations of the

organism's internal metabolism (Cohen, 1989). It is possible not only to shut down a pathway, but to

alter the regulation of pathways in order to divert the flow of material into one particular arm of a

branched pathway, thereby increasing the yield of a desired product. Similarly, these new

technologies offer the ability to alter other properties, not directly related to the pathway of interest

but related to bioprocessing, such as shifting the distribution of membrane components to increase the

tolerance of the strain to the products of metabolism. Thus, it is possible to specifically address several

major impediments to a commercially viable bioprocess: poor tolerance to high concentrations of the

desired product, requirements for expensive nutrients, production of by-products, and moderate

conversion rates.

With regard to succinic acid, near-term opportunities for metabolic engineering exist The metabolic

pathway for production of succinic acid (also called succinate) and the related dicarboxylic acids

fumarate and malate in the bacterium A. succiniciproducens is shown in Figure 7.14. The desired

pathway to succinate is the branch to the left in Figure 7.14. Genes of the final steps of this pathway

have been cloned from a variety of organisms, and mutants of these genes exist in E. coli, which

facilitates their manipulation by allowing detection of the enzyme when introduced into E. coli.

Because A. succiniciproducens is a gram-negative bacterium, it is likely that its genes will function in E.

coli, facilitating their characterization and the ability to exploit antisense technology for regulation

of metabolism in A. succiniciproducens, Potentially, reducing the flow of carbon into acetic acid could

increase the yield of succinic acid up to 50%. This goal could be accomplished by reducing or

eliminating the activity of the enzyme on the right side of Figure 7.14 that converts acetyl CoA to

acetyl phosphate (some acetyl CoA is needed for biosynthetic purposes). Alternatively, increasing the

activity of the enzyme at the branch point that adds CCh to phosphoenolpyruvate and directs carbon

toward succinate, on the left, could serve to compete more effectively for phosphoenolpyruvate.

Finally, adding genes that produce enzymes for the use of other sugars (e.g., xylose) could expand the

range of feedstocks suitable for producing succinic acid, improving the process flexibility and economics.

Currently, there are no examples of the introduction of DNA into A. succiniciproducens, but newer

methods have not yet been attempted on this strain. Regulation of the succinate pathway in A.

succinicipraducens is only partially understood (Samuelov et al. 1991), and investigation of the genetics

that regulate the incorporation of CCh should suggest additional possibilities for genetic engineering.

Activities should be prioritized to reflect the potential value of effort, the amount of time required,

and the chance of success.

7.5.L4 Advanced Bioprocessing Concepts

The product family of organic acids has been chosen as the initial candidate for developmental

research for a chemical feedstock. These include acetic, citric, lactic, and the cluster of dicarboxylic

acids (succinic, fumaric and malic acids) (Wise 1983). All are produced in relatively dilute form

because of their high level of inhibition of the microorganism. This inhibition is due both to the

chemical itself and to the lowered pH from acid production. Methods to decrease this inhibition and

increase the rate of production are needed to improve the process.

196
fi///z\ \8 pH 6.2, HIGH C02

Glucose

t

I

'.---ATP

I

+

Glyceraldehyde-3-P (2)

"--_-I pH 7.2, LOW C02

I

I

I

I

r--~ 2 ATP + 2 NADH

I

I

+

Phosphoenol pyruvate (2)

ADP

ATP~

Oxaloacetate

NADH

.-. NAD

ADP

~ATP

NADH NAD

Pyruvate s.): ILACTATE I

Malate

Fumarate

x-+-- ATP

XH~ADP

[~:0r+~~

Acetyl-CoA

Acetyl-P

ADP ---]

ATP,-,

I ACETATE I

NADH

~~NADCoA

Acetaldehyde

NADH

.--. NAD

IETHANOL I

Figure 1.14 - Metabolic Pathway for Production of Succinic Acid

197
Improvementsin production rate have been observed using various means of cell retention, including cell

recycle, membranes, and immobilization (Vickroy, 1985;Ghose and Bhadra, 1985). These methods can

lead to additional problems with mass transfer, especially if oxygen is a required co-substrate. Even

with the increased rates, the final product concentration is comparable to batch reactions because of

inhibition. Conventionally, the fermentation broth is neutralized to control the pH. This yields the

product in its salt form, which requires additional processing to produce the desired acid. Several

processes have been proposed to remove the inlubitory product from the ongoing fermentation <Busche,

1985). Extraction by solvents has been proposed, both a direct removal of the acid and a reactive

removal by forming an ester in the organic solvent phase. Extraction configurations have included

stirred tank reactors and membrane reactors. Adsorption has been proposed in various forms to remove

the acid from the broth. This has included direct addition into the batch stirred tank (with problems

of attrition and power) (Wang, 1981;Wang and Sobnosky, 1985);passing a broth recycle stream through

a side adsorbent bed (Gaillot et al., 1990); and a direct addition and removal of the adsorbent to a

fluidized bed of immobilized biocatalysts (Davison, 19918; Davison, 1992b). The biparticle fluidized

bed was referred to above as a combined bioconversion and separation process.

In general, the productstreams for organic adds vary from 1 to 10 wt % in aqueous solution as provided

by the fermentation step. Hence, the problem is one of dilute solution processing to recover the product.

Typically, the acid is recovered in salt form via addition of base and then purified with several

washings over activated carbon to remove impurities before final recovery. Several of the

aforementioned technologies have potential for both product separation and purification and waste

stream treatment. These approaches are extraction, adsorption, and membrane processing. In each of

these cases, the objective is to selectively remove the acid from aqueous solution. Several process

flowsheets exist for the recovery of acetic acid from dilute aqueous solution (Rousseau, 1987). In

particular, several amine-based extractants show remarkable selectivity for acetic acid over water

with distribution coefficients of greater than 10 as the acetic acid concentration goesbelow 0.5 wt %

(Wardell and King, 1978). In addition, data have been gathered for the distribution properties of

many fermentation product carboxylic acids, including acetic, lactic, and citric acids (Kertes and King,

1986). One could also envision placing these same types of functional groups on solid adsorbents to carry

out separations and recovery.

Although in principle structural membranes could be made to distinguish between organic acids and

water, ultrafiltration or reverse osmosis currently are not able to carry out an acceptable separation. In

principle, one could use ion exchange membranes, which use functional groups similar to the ones

considered for extraction and/or adsorption. Electrodialysis with bipolar membranes can purify organic

acids with low power requirements (Berglund et al., 1991). Electrodialysis is the most attractive of the

membrane methods (Datta, 1989) and is being developed commercially for lactic acid. Pervaporation

membranes are able to carry outsome degree of separation but are not selective enough to warrant use in

either the recovery or dehydration of organic adds.

There is no existing commercial biological process for the production of succinic acid. The acid is

currently synthesized from maleic anhydride for use in making coatings, dyes, esters, and polymers.

Key process-related problems have been identified and put in the following order of priority: (1) the

formation of dilute product streams and the cost of recovery; (2) the elimination of the salt waste from

the current purification process; (3) the reduction of inhibition caused by the product succinic acid on the

fermentation of itself; (4) the interference in slowing the reaction and complicating the separations

caused by. other by-products; (5) the reduction in the use of expensive nutrient supplements (e.g.,

vitamins) for the microbes; (6) the enhancement of the overall conversion rates; and (7) the need to

increase the feedstock flexibility beyond glucose.

Succinic acid is an intermediate component in the citric acid cycle (or Kreb's cycle) common to all

respiratory organisms. Therefore, many organisms produce small quantities of this acid along with

their primary metabolic products. It is more difficult to find a single organism and process that

accumulates succinic acid. The anaerobic Anaerolriospirillum succiniciproducens will ferment sugars and

198
carbon dioxide to more than 40 gIL succinic acid in the form of calcium succinate (Datta, 1991). Candida

brumptii will produce up to 24 gIL succinic acid Perliter from 80 gIL paraffin but not from glucose (Sato

et al., 1972). Under a limited range of partial oxygen deprivation, Breoibacterium flavum will make

up to 30 gIL succinate instead of its primary product L-giutamate (Okada et al., 1961). Two-stage

approaches are more common. In these, first the sugar or starch is converted by one microbe into an

organic acid such as fumaric, malic, or citric acid (Ling and Ng, 1989). Then a second microbe transforms

this acid into succinic acid. Different pairs of microbes have been used, including the fungi Rhizopus to

produce fumaric acid and Enferobacter aeTogenes to convert fumaric into succinic acid (Takao et al.,

1973; Hotta and Takao, 1913). Aspergillus oryzae has been used to produce a mixture of acids, and

Lactobacillus [ermenium to convert these to succinic acid. Citric acid also can be converted

anaerobically into stoichiomebic quantities of succinate and acetate (Cselovsky et al., 1992). These

studies have been performed largely in batch culture, but there have been limited attempts at

continuous culture.

Approaches to succinic acid overproduction will rely, first, on the selection of the microbial system

(pure culture or a synergistic association of a mixed culture). There is potential for improvement of the

yields by genetic manipulation, (see section 7.5.1.3). Also the optimization of production due to culture

conditions will be needed. Some apparent waste materials, such as whey, may also have potential as

feedstocks (Compere and Griffith, 1976). Because at least one organism (C. brumpiii) can ferment

hydrocarbons (paraffin) into succinate, it is possible that thermal!chemical processing of biomass into

hydrocarbons may form a feedstock for this bioconversion, which might be coordinated with the

thennal/chemical processing effort of the Alternative Feedstocks Program. The choice of feedstocks is

important because carbon dioxide also is required for goodyields in the anaerobic systems. The carbon

dioxide is incorporated into the succinate product. Cell retention methods such as immobilization will

need to be tested to increase overall rates and to decrease sterilization requirements.

One of the major reasons for the low succinic product concentration is the inhibitory nature of the

organic acids. Protonated organic acids (as opposed. to the ion "salt") freely cross the cell membrane and

thus are able to deplete the necessary proton gradient and weaken the cell metabolism. Succinate

appears to be more inhibitory than either acetic or lactic acids. This makes this fermentation a strong

candidate for some form of in situ product removal. This removal might be possible using adsorbents in

the bipartic1e fluidized bed, as suggested for lactic acid. Another possibility is precipitation of

calcium succinate directly in the fermentor (Datta, 1991),but this is not ideal due to the production of a

salt waste. The adsorption of succinic acid or electrodialysis from a recycled sidestream may allow

better optimization of both the bioconversion and the separation steps. Datta et al. (Datta, 1991) found

that recycling of part of their "spent" media improved their overall process economics. A major

disadvantage of the precipitation method is the production of gypsum as a waste by-product.

Precipitation is expected to require less energy than adsorption-based methods if the energy required to

treat and produce the acids and salts is not considered. Downstream processing may be greatly

improved by the use of adsorbents, ion exchangers, or membranes. The technologies described here are

listed in Table 7.11 with a qualitative criteria evaluation. The base case is a standard free-cell batch

fermentation for organic acids with production recovery by subsequent precipitation and purification.

Productivity or rate is improved and product inhibition is reduced by removing the inhibitory succinate

in the biparticle fluidized bed reactor (FBR), the precipitation/fermentor, and the sidestream

absorber. The two-stage fermentation process is expected to decrease productivity because an

additional vessel is required. A single-stage mixed culture was seen to improve productivity. Yields

were improved in these processes. Separation development to deal with the dilute products will focus

on adsorption methods that are low energy; however, precipitation is generally a lower energy process

but it produces a substantial waste product. The use of membrane electrodialysis shows value for the

near- or mid-term. The use of adsorption or membranes would reduce the production of a salt waste.

199
Table 7.11 • Performance Criteria Comparisons for Advanced Technologies Succinic Acid Production

Impact on Criteria

Advanced Technology Productivity Yield Product Energy Use Environmenial Operability Time frame

Quality Impact

Simultaneous Fermentation & Separation

Biparticle FBR + + + . + 0 mid

Precipitation & + + + 0 - 0 near

Fermentation

Fermentation Sidestream + + + - + + long

Adsorption

Separations

Separation by Adsorption 0 0 + - + + near

Membrane Electrodialysis + 0 - 0 + 0 mid

Other Processes

Use of Thennochemically - long

Treated Feedstocks

Two-stage Fermentation - + 0 0 - mid

Combined Mixed Culture + + 0 0 0 - mid

The base case here is a standard free-cell batch fermentation for organic acids with production recovery by subsequent precipitation and purification. In the

criteria comparison tables, "+"indicates an improvement, "_" a disadvantage, "0" neither an advantage or disadvantage, and a blank insufficient knowledge to

evaluate at this time.
- :», , " :

7.5.2 Neutral Solvents (Butanol)

Another class of chemical feedstocks that potentially can be manufactured by biotechnology is the

neutral solvents such as butanol, acetone, and acetaldehyde.

Butanol is a commodity chemical feedstock and solvent that, early in this century, was primarily

made by industrial fermentation (see reviews) (lones and Woods, 1986; Linden et al., 1986). The

fermentation process declined after World War II due to both the rise of the petroleum industry and the

increase in raw material costs (molasses). Butanol is now synthesized chemically from petroleumderived ethylene and triethylaluminum or carbon monoxide and hydrogen. Continued research in

bioconversion of renewable resources and the actual and potential increases in petroleum costs have

encouraged renewed interest in butanol fennentation. Butanol may have an additional market as an

oxygenated fuel additive (Ladisch, 1991).

Butanol is the primary product of the fermentation of sugars by various bacteria, in particular

Clostridium acetobutylicum. This is a complex fermentation, with, first, an acidogenic phase producing

butyric and acetic acids and, then, a solventogenic phase producing butanol, acetone, and ethanol. Both

the products and the lowered pH can be inhibitory to the continued fermentation. This has limited

final butanol concentrations to a maximum of 15 gIL in batch culture, with generally much lower yields.

7.5.2.1Market Definition

Butanol 'is used for a wide variety of applications and many derivatives are produced from it (see

Table 7.12). Butanol and its derivatives are currently produced from petrochemical feedstocks;

commercial production of butanol and some derivatives is sufficiently high to qualify them as

commodity chemicals.

The industries that currently produce those chemicals listed in Table 7.12 are stable, and all expect

growth. Stable growth in production of butanol and some of its derivatives is partly due to the lower

environmental risk posed by the usage of these chemicals compared to other more hazardous chemicals

used in the past (Chemical Marketing Reporter, 1991; Chemical Economics Handbook, 1990). This

aspect of the future marketing potential for butanol cannot be overstated, as hazardous waste issues

have become very important to industry for economic reasons (Russell et al., 1992; Stavins and

Whitehead, 1992).

A primary consideration in terms of marketing new production processes for these chemicals is the low

market price for most of them. Any new process involving butanol or its derivatives will have to be

strongly competitive in terms of product selling price (which is not necessarily equal to the market

price, but certainly is strongly related to that price).

The markets for the materials produced from butanol and its derivatives (i.e., paints, resins, textiles,

polyvinyl chloride (PVC), and plastics) are stable, and continued growth of these materials is likely

(Chemical Marketing Reporter, 1991,Chemical Economics Handbook, 1990).

Two major concerns that have always existed for butanol producers are propylene price fluctuations due

to irregular petroleum prices and dependence on housing and automotive markets (Chemical Economics

Handbook, 1990). In the recent past, some tightness of butanol production has been experienced due to

limited petrochemical feedstocks (Chemical Economics Handbook, 1990); this type of situation

represents an opportunity for the introduction of a new process technology based on an alternative

feedstock whose supply is not limited, i.e., biomass.

Domestic producers of butanol and its derivatives include BASF (butanol, butyl acetate, ,butyl

acrylate/methacrylate); Chern Service, Inc. (butyl acrylate/methacrylate); Dow Chemical

201
Table 7.12· Market Information for Butanol and Potential Derivatives!

Chemical Growth! Production' Price' Price Usage" Feedstock"

StabilityS

N-Butanol S (2.5) 0.6 (1.3) 90 (41) + Solvent for coatings and resins, Propylene,

feedstock chemical butyraldehyde, ethylene

N-Butyl Acetate 5 (1) 0.1 (0.23) 110 (50) + Solvent for coatings N-Butanol

N-Butyl Acrylate 5 (2)8 0.3 (0.7) 158 (72) + Paint polymers, textile N-Butanol

emulsions, PVC impact

modifiers

N-Butyl 5 (2)8 - 211 (96) + Resins, coatings N-Butanol

Methacrylate

Butyl Glycol 5 (2) - 81-194 + Coatings solvent, plasticizer, N-Butanol, ethylene

Ethers (37-88)9 feedstock chemical oxide

'Source. or Inrorm.llon .re: Chlmlcal Ma,htlll, BIlOttI' 1"1; Ellc,do/H4/Q o/ChlmJclIl TlchllOlofy 1982;ChlmJclII Ecollomicl HII,,46001:1990.

'Predlcted growlh or Indu.lry over nexl one 10Ihree yun. (5) IndlClld ...ble growth predicted. Numenl. IndlCllepredicted percenll.e .rowlh Increllelyen.

'Currenl .nnu.1 producllon lor U.s., melrlc lonl x 10'/yr (billionIblyr). (.) Indlc.lel cunenl production nol known .1 Ihl. lime.

'Currenl mnkel price, bulk qu.nlllles, tIki (t/lb).

'(+) IndlCllesIh.llhe m.rket price hu remaIned .lIble over Ihe 11111.5 ye.rs.

'Currenl primary ullllz.llon lor chemlc.l.

'Currenl petrnchemteel leedstock. u.ed 10 produce chemIcal.

'Comblned .ro~h r.le lor bUlyl acry'ale and bUlyl methacrylale.

'Prlce nnle b ror rour dlrterent butyl glycol ethen; low end a elhyleneglycolmonobulyl elher, hllh end = dlelhyleneglycol monobulyl elher .ceille.
U.S.A. (butyl glycol ethers); Eastman (butanol, butyl acetate, butyl glycol ethers); Hoechst Celanese

(butanol, butyl acetate, butyl acrylate/methacrylate); Rohm and Haas Co. (butyl

acrylate/methacrylate); Shell (butanol, butyl glycol ethers); Union Carbide (butanol, butyl acetate,

butyl acrylate/methacrylate, butyl glycol ethers); and Vista (butanol) (Chemical Marketing Reporter,

1991; Chemical Economics Handbook, 1990).

7.5.2.2 Process Evaluation

The base-case process concept for the bioproduction of butanol (Glassner, 1991) is illustrated in Figure

7.15. The process is modeled as a two-stage fermentation. The first stage is a series of continuous

fermentors. The second stage is a batch fermentation. The size of the base-ease plant is at the scale

equivalent to processing all of the hydrolyzed starch from a 70,000 bushel Per day corn wet-milling

plant. The productivity and yield data used in this design were translated from small-scale batch and

continuous fermentation data.

Glucose syrup is the feedstock used in the simulated process. This is a readily available feedstock,

requiring little pretreatment other than sterilization for its use as a fermentable substrate. If the

economics of this acetone-butanol-ethanol (ABE) process were favorable using glucose syrup, then this

process would be considered a near-term opportunity. However, the FRF for butanol from glucose syrup

is quite close to one, meaning that the value of the products obtained is only slightly greater than the

cost of the feedstock. For this reason a restrained approach to the engineering and economic analysis

was used. The economics of the process were assessed after various stages of completion of the

engineering analysis.

The first assessment of the economics was performed after all of the plant equipment associated with

production had been sized and costed. This, of course, required that a complete material and energy

balance be performed for this section of the plant. The equipment in this section includes the feedstock

and nutrient storage vessels, the continuous sterilizers, the seed train fermentors, the production

fermentors, and the miscellaneous pumps and heat-exchangers.

The predicted selling price for this broth was determined without taking into account any of the utility

costs. Operating labor and labor related costs likewise were not considered. The only raw material cost

considered at this stage was for the glucose syrup. A by-product credit was taken for the acetone and

the ethanol in the fermentor broth. The predicted selling price of the butanol in the fermentor broth

was determined to be $0.54 per pound; the current market value of butanol is approximately $0.41 per

pound.

It is clearly a longer term opportunity to complete the design of this process, as it stands, using glucose

syrup as the feedstock. Additional engineering analyses of the ABE process will be performed in the

future using the other plant designs described in section 6.4.2.1. In these subsequent designs,

consideration will also be given to the various advanced technologies that could improve the fermentor

volumetric productivity and to the advanced feedstock pretreatment and product separations

technologies.

Butanol is a candidate that will benefit from the iterative nature of the screening process. The current

analysis, however, suggests that the ABE process be placed in the long-term or mid-term opportunity

category. Attention can then be shifted to another candidate whose "window of opportunity" may be

more near term,

The manufacturing cost summary for the base-case design is given in Table 7.13. Again, this summary is

for an incomplete engineering analysis. .

203
Waste Treatment

Hydrogen, Carbon Dioxide Recovery

I Recycle

-- ,. I -- Sterilization -- Fermentation .

- Distillation Feed

U

Inoculum

Build-Up

Ethanol-Water -- tility Systems: Acetone -- Cooling Water Butanol --- Fermentation Gas

Process Water

Plant/Instrument Air l'

CIP/CS System Solids - Liquid-Solid - I---

Process Steam Separation

u

Waste Treatment

Figure 7.15- Process Conceptfor Bloproductlon of Butanol
Table 7.13 - Manufacturing Cost Summary for Butanol Production from Glucose Syrup

Butanol Production from Glucose Syrup; Basis =70,000 bulday Com Wet-Milling Plant

Location: Midwest AnnualCapacity: 175,000,000 lbs butanol

EffectiveDateto Which Estimate Applies: 1990 Cost Index Type: CE Plant Index

Predicted SeUingPrice: $0.54 Cost Index Value: 357.7

Fixed Capital: $50,809,312

Working Capital: $5,080,931 Total Capital Investmen 555,890,243

Production Cost kSlJrr $Jlb

RawMata'iaJs $76,014 SO.434

By-Product Credits $31,000 SO.I77

Operating Labor $0 $0.000

Labor Related Costs SO SO.OOO

Capital RelatedCosts $8,881 SO.051

Sales RelatedCosts S25,929 SO.148

Steam, 50 psig @ SO.OO6/lb SO SO.OOO

Eledricity@ $O.045/kW-br SO SO.OOO

Cooling Wakr@ SO.lO/kGal SO SO.OOO

Process Wa1er@SO.10/kGal $0 SO.OOO

Waste Treatment (ill $4. 16/kGal SO so.ooo

Total Expense S79,825 SO.OOO

Revenue from Sales S95,485 SO.546

Net Annual Profit S15,660 SO.089

Annual Income after Taxes S11,476 $0.066

Assumptions

Plant Life, yrs 20 Invemncot Tax Credit, First Year 0.0%

DCF Rate-ofRetum 10.00% WorkingCapital. PercentofTotalFixed Capital Investment 10.0%

CapitalCharge Factor 20.53%

Equipment Depreciation, (maight-line), yrs 10 PercentofTotal FixedCapitalInvestmentSpent in Year-3 30.0%

Buildings Dcprec:iation, (straight-line),yrs 30 PercentofTotal FIXCd Capitallnvcstment Spent in Year -2 50.0%

FederalTax Rate 37% PercentofTotal FixedCapita1InvestmentSpent in Year -I 20.0%

Equipment Salvage Value 0.0% PercentofStalt-Up Costs Spent in Year -1 30.0%

Raw Material Costs

Glucose Syrup Cerelose 2617 Com Products SO.1025 /lb

205
Labor

Operators @ $30,000 yr Iyr

Foreman @ $35,000 yr Iyr

Supervisor @ $40,000 yr Iyr

Total Operating Labor Iyr

Labor Related Costs

Supervisory& Miscellaneous Labor,PercentofOpcrating Labor 20.00% /yr

PayroU Overhead, Percentof OperatingLabor 32.50'Yo /yr

LaboratoryCbatges,PercentofOperatingLabor 15.00% Iyr

Total Labor Related Costs Iyr

Capital Related Costs

MaiDtawJcc, PercentofPlant Cost 7.50'Yo $3,505,843 Iyr

Operabng Supplies,PercentofPlant Cost 1.75% $818,030 Iyr

Enviromncnta1, PercentofPlaDtCost 2.75% 51,285,476 Iyr

Local Taxes, PercentofPlant Cost 2.00% 5934,891 /yr

Insunmce, Percentof Plant Cost 2.00% 5934,891 /yr

Plant Overhead Costs, PercentofPlant Cost 3.00% 51,402,337 Iyr

Total Capital Related Costs 58,881,468 /yr

Sales Related Costs

Pat=ts& Royalties,P=t ofSales 0.00% SO Iyr

Packaging& Storage 3.50% $4;426,977 Iyr

Adminislrative Costs 6.00% $7,589 ,104 Iyr

Dislribution& Sales 6.00% $7,589,104 Iyr

Researc:h & Development 5.00% 56,324,253 Iyr

Total Sales Related Costs $25,929,438 Iyr

Equipment

Purchased EquipmentCost $8,431,826

Shipping.PercentofPtm:based EquipmcotCost 10.0'Yo $843,183

Piping,PercentofPun:bascd EquipmentCost 45.0% $3,794,322

Elcdril:a1, PercentofPurcba.sed Equipment Cost 12.5% 51.053,978

1nstnuncutation,PercentofPurcba.sedEquipmentCost 35.0% $2,951,139

Utilities,PercentofPtm:based EquipmentCost 80.0% 56,745,461

Foundatious,PercentofPurcbased Equipment Cost 10.0% S843,183

Insulation,PercentofPtm:based EquipmentCost 5.0% 5421.591

Painting,Etc.,P=tofPtm:based EquiplDcnt Cost 5.0% $421,591

Total Purchased EquipmeDt IDstaUed $25,506,275

FIXed Capital

Yani Improvements, PercentofF"vced Capital Investment 1.5% $762,140

ServiceFacilities,Percent ofFixed CapitalInvestment 7.0% $3,556,652

Land, Percentof FixedCapital1nvestmellt 3.0"10 SI,524,279

Engineering& Supervision,PcrocntofFixcd CapitalInvestment 10.0% 55,080,931

Coastnu:tion Expenses, PercentofFixcd CapitalInvestment 4.8% $2,438,847

Contra.ctor's Fcc, PercentofFixcd CapitalInvestment 3.0% $1,524,279

Contingency. Percentof FixedCapital Investment 7.5% $3.810.698

Start-Up Costs, Percentof'Fixed CapitalInvestment 8.0% $4.064,745

Buildings, Percentof Fixcd Capital Invcstmcot 5.0% 52,540,466

Total Find Capital Investment $50,809,312

206
.,

7.5.2.3 Application of Genetic and Metabolic Engineering to Butanol Production

The pathway for butanol production is shown in Figure 7.16. This pathway is composed of two distinct,

regulated phases: an early phase of acid production followed by a phase of solvent production. In the

upper portion of the pathway, one-third of the carbon from glucose is lost as carbon dioxide. During the

acidogenic phase, butyric and acetic acids are produced in a ratio of about 2:1; they are then

reassimilated in the solventogenic phase and reduced to butanol and ethanol, respectively (Jones and

Woods, 1989). The final disbibution of solvents on a molar basis is approximately six parts butanol to

three parts acetone to one part ethanol. The regulation of solvent production is becoming fairly well

understood (Gottschalk and Grupe, 1992), and the molecular biology of the favored organism, C.

acetobutylicum, is fairly well developed. Several genes of the butanol pathway have been cloned, and

stable introduction of DNA into this strain has been reported (Mermelstein et al., 1992). In principle,

elimination of the acid-producing phase and deregulation of the solvent-producing enzymes through

genetic engineering could give a two-fold increase in the molar yield of butanol. Alternatively, in a less

technically ambitious task, elimination of enzymes that produce acetic acid in the acidogenic phase

and ethanol in the solventogenic phase could increase the molar yield of butanol by 15%. Mutation of

enzymes that affect the production of H2 should also favor solvent production. Alterations of the

membrane of the host strain to give greater tolerance toward butanol could have even more economic

impact because the toxicity of butanol, which is mediated through membrane effects, severely limits

the final concentration of butanol that can be achieved.

7.5.2.4 Advanced Bioprocessing Concepts

As discussed earlier, key processing issues for butanol production are the dilute product and its

separation, inhibition of rates caused by butanol, and the low yields. Removal of the inhibitory

product from the ongoing fermentation process has been suggested by many researchers as a method to

alleviate product inhibition and improve the process. Roffler et al. (1991) and Groot et al. (1992)

review several possibilities for extractive bioconversions. The key advantages suggested for extractive

bioconversion are higher feed concentrations leading to fewer process wastes and reduced product

recovery costs compared to distillation.

Possibilities for in situ product removal include pervaporation (Friedl et al., 1991), the use of hollowfiber reactors (Shukla et aI., 1989; Kang et al., 1990); the use of solid adsorbents (Ennis et al., 1987;

Davison, 1992; Gaillot et al., 1990; Wang and Sobnoslcy, 1985); and the use of an immiscible extractive

solvent. Key issues are the extractant toxicity and capacity as well as the actual contacting scheme and

its operability (Broce and Daugulis, 1991). Many solvents have been tested for the acetone-butanol

fermentation (Shukla et al., 1989, Ishii et al., 1985; Evans and Wange,1988; Wayman and Parekh,

1987). Oleyl alcohol is commonly used because of its low toxicity, reasonable distribution coefficient,

and selectivity for butanol.

Most studies of extractive acetone-butanol "fermentation have been performed in a batch reactor (Ishii

et aI., 1985; Evans and Wang, 1990) with free cells. Wayman and Parekh (1987) performed a sequential

batch extractive fermentation with cell recycle. Another approach is to continuously extract the

butanol in a side stream of the fermentor. Roffler et al. (1988) performed a fed-batch fermentation with

a concentrated glucose feed using an extraction column on a recycled side stream and achieved a butanol

productivity of 1 gIL-h. Eckert and Schugerl (1987) used a continuous stirred fermentor with a

membrane filter to recycle the cells and provide a cell-free broth to an extraction cascade. The lack of

direct contact between the cells and the organic extractant allowed the researchers to use the more toxic

extractant, decanol. Allen and coworkers have proposed using a immobilized-cell fluidized bed

bioreactor with a concurrent immiscible liquid extractant (Busche and Allen, 1989); promising

experimental results of this system have been obtained by Davison and Thompson (1992).

207

., -.

c. acetobutylicum can ferment both glucose and xylose and thus can improve the yield from

lignocellulosic hydrolyzates. Simultaneous saccharification and fermentation (SSF) also has been

tested preliminarily for the production of butanol (Shah et al 1991). This is an anaerobic fennentation

with an inhibitory product, butanol; therefore, the need for strict sterilization requirements is likely to

be reduced.

The economics of extraction in a free-cell, fed-batch butanol fermentation as well as in a continuous

immobilized-eell reactor have been examined (Roffler et al.; 1987) and compared to conventional

fermentation (Busche, 1991). Several of these concepts are evaluated against the six criteria, drawing

heavily on the references (Roffler et al., 1991; Bruce and Daugalis ,1991; Busche, 1991) in Table 7.14.

The base-case here is a batch fennentation of biomass-derived sugars followed by distillation. Most of

these extraction-based technologies .have shown improvements in productivity, resulting from the

advantages of continuous operation. Several liquid-extraction reports have shown improvements in

yield as well. Perstraction has major operational difficulties and will not be considered initially.

Adsorption also has difficulties in situ, and the current adsorbents are poor for neutral solvents.

Pervaporation and extractive fennentation are see as the most promising processes for further research.

These technologies also can be considered as a distinct separation process with similar conclusions.

209
Table 7.14· Performance Criteria Comparisons for Advanced Technologies Butanol Production

Impact on Criteria

Advanced Technology Productivity Yield Product Energy Use Environmental Operability Time frame

Quality Impact

Pervaporation (in situ) ++ 0 ++ ++ + 0 mid

Gas Stripping (in situ) + 0 0 + 0 0 near

Adsorption (in situ) 0 0 0 + 0 0 mid

Perstraction (in situ) + 0 + + + - long

Liquid Extraction (in situ)

- fed batch + + + ++ 0 0 near

- sidestream extraction + + + ++ 0 0 mid

and recycle

- continuous FBR ++ + + ++ 0 0 mid

Simultaneous

Saccharification and 0 + + 0 0 0 mid

Fermentation

The base case here is a batch fermentation of biomass-derived sugars followed by distillation. In the criteria comparison tables, "+" indicates

an improvement, "_" a disadvantage, "0 " neither an advantage or disadvantage, and a blank insufficient knowledge to evaluate at this time.
8.0 RECOMMENDATIONS

The qualitative background and market information and quantitative assessment methodology

presented in this report are an attempt to identify RD&Dopportunities for converting biomass to useful

chemical products. Such a process should have some predictive power, and the ability to answer the

question first posed in section 1.1.2: Given a wide range of possibilities, how can an infonned decision be

made as to which materials to investigate more thoroughly? However, because a broad spectrum of

readers is expected to use this report, developing a single set of recommendations to apply to all

situations is not reasonable. Therefore, this section will outline our own general criteria thought

important to an informed decision, with the understanding that each reader will bring additional

criteria to the decision making process, developed to reflect the needs and realities of their own

situations. These unique and individual criteria could lead to completely different recommendations

than those listed in this section. The decision making process and the logic behind it as described in

this section will reflect the authors' original task to use this methodology to recommend promising

RD&D areas most appropriate to the different research charters of certain DOE offices. Those

recommendations are summarized in section 8.6.

8.1 Criteria for R~ommendations

Figure 8.1 summarizes the chemicals and processes assessed for the thermal/chemical portion of the

report. A similar summary for bioprocesses is shown in Figure 8.2. No single criterion was used to

identify a chemical or process as a promising opportunity. Rather, the combination of a number of

favorable features was most important to the final decision. These criteria included:

• Comparative evaluation of Taw material cost contribution

This simple comparative assessment methodology, whose development and use are described in detail

in sections 4.0 and 5.0, helps determine which of the chemicals or processes in the original portfolio

offered the greatest opportunity from an economic standpoint. The value of the ratios from this

evaluation, summarized in table 5.1, give a rough "performance index" by which a new biomass-based

process can be judged. In some cases (e. g., acetylated wood or starch plastics, see section 8.2.1),

sufficient information was available to perform a more detailed analysis of costs (section 5.4). These

results can also be used to compare a new chemical or process to existing technology.

• Relative maturity of new processes

Although a favorable raw materials cost ratio is important, the amount of knowledge about the actual

performance of a given process is also important to the final decision. Some chemicals or processes may

exhibit high ratios from the raw materials cost comparison, but the actual process chemistry may not be

clearly defined.

A number of the chemicals or processes evaluated have data from operation near 50 kg/h. However, in

others, technical data was generated at considerably smaller scale. Because the different technologies

investigated are at various levels of maturity, a final recommendation should consider if a process is at

engineering scale and perhaps ready for pilot scale tests, requires scaleup to engineering level for

confirmation of their initial promise from the simple screening results, or is at a more conceptual, and

hence, smaller scale that would require longer term development. These considerations help both to

identify specific product opportunities and give indications of general areas of RD&D that could lead

to useful chemicals and materials of commercial interest.

211
• Olefins

Zeolite

Catalysis

8TX

r£]

II Z5M-5

Fast Catalysis

Pyrolysis BTIC

PIN Oils

I SolventI

I Separation Aqueous

Fraction I LEVOGLUCOSAN ----

I Gasification: • • .Syngas. ACETIC ACID

I

IBiomassI : Lignin

I. Hydrotreating

I

I

I Methanol:

Clean

Fractionation

I

• ICelluloseI GLUCOSE I LACTIC

ACID

I Hemicellulo~

I XYLOSE FU~LL

I

BUTADIENE

PENTANES, PENTENES

COPRODUCTS

BENZENE

TOLUENE

XYLENE

PHENOLICS

HYDROXYACETALDEHYDE

MIXED ACIDS

RESORCINOL

PERACETIC ACID

ANTHRAQUINONE

PHENOLICS

METHYL ARYL ETHERS

SORBITOL

MANNITOL

GLUCONICACID

5-HYDROXYMETHYL

FURFURAL

LEVULINIC ACID

ACRYLIC ACID

PERACETIC ACID

XYLITOL

FURAN

TETRAHYDROFURAN'

FURFURYL ALCOHOL

Fl.. 1.1~

}Pro' val

l.. ,,"Ot-

.ew,
ANTHRAQUINONE

PERACETIC ACID

....-------.....ILl . gm"11------------------ I

-------I Hydroxy .... , --1.1 Acetaldehyde~~"'------ Adds 1 • Kraft

...------t Black

Liquor

•

Waste

Material

1- .. Potato Fermentablf,.. -tl Lactate .... I _

Waste t-------tSugars I Esters I ACRYLIC ACID

PERACID ESTERS

Figure 8.1 - continued

213
PBTresm

:

(aulomotive andelectrical parts)

Anti!cptics

PVC: plastic.!

Agricultural Chemicals

Consumer

Products

Nylon

Perfumes andCosmetics

Lacquers

Pharmaceuticals

Dyes

Urethane Foams

Textiles

Detergents

Flavor Ingredients

Lubricants

Pholographic Fihns

Synthetic Rubbers

Styrofoam or Plastic Substitutes

Synthetic Waxes

Environmentally SafeSoaps

Sweeteners

Adhesives

[ Si1Jng AgentsI

Secondary

Industrial

Uses

I Stabilizers

I

I Thickeners

I

I Emulsifiers

I

I Antioxidants

I

I Plasticizers

I

I

Thermoplastics

I

I Cala\y!ts

I

I HumectantsI

I Mordants

I

Butanol

Primary

Industrial

Chemicals

i.

i

!i

II uctic AddII .. . :

r·························

II AceloneII

II "~,,~"II

\IL...-.....-....-...-....-....-.. _II

If °_;11

!!I

IL -A-ceta-Id-e-hy-d---lel!

l...

j••.•.••••••••.••.•.•••.••.••..••••••.••••••j

II Acetic AcidII

...II

II

Solvents

Product

Family

Biopol)mers

Mi1cellaneous

Organics

Organic Acids

Comstover

Municipal solidwaste

Blacbtrapmolasses

Forestry residuals

Silviculture

Sugarcaneresiduals

Sugar cane

Apple Pomace

Canemolasses

SpentsuUite liquor

Beetmolasses

Potalo

Jerusalem artichoke

Feedstocks

Sorghum

Potalo processing residuah

Com

Figure 8.2 - Production of Consumer Products from Renewable Feedstocks
• Market and environmental impact

In addition to the technoeconomic aspects, one must also consider the markets of existing products and

the potential impact of new products on markets, and attempt to answer questions such as: what is the

competition for a selected material? Does it make sense to develop a small volume process when

efficient high volume processes already exist to the same material? An evaluation should also overlay

the environmental impact of both current processes and the emerging technologies. This approach takes

the market, economic, environment, and energy impact of the route from the start, and allows a better

selection of candidates of industrial relevance for potential near-term commercialization, mid-term

promise, and long-tenn RD&D of relevant interest to the industry's needs.

• Potential scope of process

The possible range of applications from a given RD&D area should be considered. A chemical/process

that could have a "cascade" effect on the costs and use of a number derivative chemicals and materials

could offer a greater range of opportunities than focusing all attention on a single process to a single

material.

Sections 8.3-8.5 list RD&D opportunities that have been identified through use of these criteria and

have been separated roughly into near-, mid-, and long-term categories. Note that not all materials

evaluated in sections 4.0 - 7.0 show up in the recommendations section. However, the failure to include

a certain material does not mean that it is not worthy of consideration. .Instead, it reflects the

possibility that it might not compete with current existing routes. Alternatively, its absence could

suggest research possibilities that, if realized, would make a new proposed process from biomass more

Viable.

8.2 Crosscutting Tedmical Barriers

Many technical issues have been discussed in this report, both generically and specifically for certain

target products. Although this program will focus on commercialization of specific representative of

chemical product families, there are barriers that are common to many of the potential products from

renewables. It is clear that improvements in a specific production scheme could have applicability to

other products. For convenience, the barriers can be considered in the areas of the process scheme, the

intrinsic biocatalyst itself, and infrastructure issues.

A key barrier inmost bioprocessesis that fermentations produce dilute aqueous products. Techniques to

improve separations of these dilute chemicals are important and necessary to make purification more

energy .efficient and environmentally sound. Processing yields can be increased to eliminate byproducts; this will improve the direct costs and make the separations easier. Conversion rates need to

be increased by improved process design to decrease capital costs. The feedstocks and their

pretreatments must be evaluated and improved to improve feedstock flexibility and to reduce the need

for nutrient supplements such as vitamins. Some of these process concerns can also be addressed by

modifying the existing biocatalysts through genetic manipulation. These manipulations could improve

yield by decreasing by-product fonnation, improve the tolerance of higher levels of product, lower the

need for added supplemental nutrients, and increase the intrinsic rate.

Other process barriers are the determination of the final end product or end use of the intennediate

chemical. Subsequent conversion may be by thermal/chemical or biological means. There are

additional purity and product quality issues that must be addressed for subsequent conversion. This

program must also demonstrate the technology at sufficient scale to show the actual economics and

capitalization risk involved. The optimum scale for a pre-commercial bioconversion plant from

renewables has not been determined and will be influenced by feedstock transportation costs as well as

direct process costs.

215
Broader infrastructure barriers that must be examined for the larger industry and for specific products

included which will need to be developed include: the interface between the agribusiness and the

chemical processing industry, the Presence of a qualified pool of trained personnel for this new industry

<National Academy of Sciences 1992); and the consumer acceptance or awareness of "green" Products

from renewables. Much of this discussion parallels conclusions reached by others such as the National

Academy of Sciences (1992).

8.3 Near Term Opportunities

The evaluation process identified several possible RD&D opportunities that fall roughly into the near

term timeframe. For bioprocesses, one opportunity was identified among organic acids, succinic acid

production. For thermal chemical Processes, two near term targets were also identified which will

need some further evaluation prior to actual development: cellulose/lignin/hemicellulose Production

from clean fractionation processes and acrylic acid production. Additional near-term targets in

thermal chemical processing are also listed and additional bioprocessing options were discussed in

sections 6.0 and 7.0, and specifically in Table 75 .

1. Succinic acid. The emphasis in succinate-specific RD&D will focus on the bioconversion and

separation steps with additional emphasis on market and infrastructure issues. As stated

earlier, near-term development will use glucose syrup from corn wet milling in the near-term

and encourage mid-term development of hydrolysis of lignocellulosics. However, this will

depend on a suitable carbohydrate media from inexpensive bioresources. Immediate efforts

will be needed to choose the best currently available organism (most likely A.

succiniciproducens). More complete bioconversion Processing data will be needed for succinic

acid in the near-term.

The selection or creation of a bettersuccinic acid organism (or mixed culture) is a near-term goal.

Short-term research with genetic engineering techniques can determine the amenability of the

succinic producer to genetic manipulation. Then, a near-term goalwould be to improve the yield

of succinic acid from sugars. Genetic alterations to improve the tolerance of the microbe to low

pH and succinic acid would follow as a mid-term goal.

For in situ Product removal to alleviate the problem of product inhibition, the precipitation

and fermentation process is nearly available. However, the adsorption-based methods

<biparticle FBR and the sidestream absorber with recycle) appear to be the most promising.

Separations development will emphasize adsorption in the near term and membrane

electrodialysis in the near- or mid-term. RD&D in the genetic and process areas will address

the highest priority barriers discussed earlier. In addition, the subsequent conversion of

succinic acid into other chemical products must be examined both in terms of the purity needed

for the next process and the biological or thennallchemical route to be used. Markets studies

will continue to estimate future trends in potentially competitive technology and consumer

acceptance and awareness of new "green"products.

2. Clean fractionation of biomass. Throughout this assessment of chemicals and materials from

biomass, the past literature and commercial practice for separating the three components of

lignocellulosics (cellulose, hemicelluloses, and lignin) has met with difficulty. Cross

contamination of one fraction with traces of various components of other fractions reduces its

value. The subsequent purification step necessary to high purity individual components also

reduces the yield and thus increases the cost of the product.

The key to the effective and economic conversion of lignocellulosic biomass to chemicals is using

of all three biomass fractions as sources of valuable chemicals and materials. Thus developing

a technology that fractionates the three key biomass polymeric components in a clean manner,

216
•

•

•

•

3.

that is cost-effective and environmentally safe is required. An assessment of the new NREL

clean fractionation process indicates that it offers conditions that meet these requirements.

Several research needs can be identified as part of this analysis:

The process needs to be investigated at larger scales and the individual product streams

assessed for their value as feedstocks for chemicals and materials production.

By virtue of their lower cost, it is envisioned that these fractions could be used for

manufacturing a large number of chemicals or materials, from either chemical or thermal

processing or bioprocessing. As an example, the impact of clean fractionation is reflected on all

monomeric carbohydrate derived chemicals derived from cellulose and hemicelluloses. It spans

conventional products such as xylose, xylitol, furfural, furan resins, tetrahydrofuran and

glucose, gluconic acid, sorbitol, mannitol, levulinic acid, succinic acid, as well as all the

potential chemicals that can be derived from bioprocessing sugars, as described in sections 6.0

and 7.0 of this report. The raw materials cost ratio for each of these products is favorable when

prepared from one'of the primary products of the clean fractionation process. Essential for the .

success of the derivatives is the efficient hydrolysis of the cellulosic/hemicellulosic fractions.

High-yield routes will be able to decrease the costs from those projected in this report.

In our view, this or other cost effective technologies that accomplish a clean separation of

biomass polymers need to be developed before commercially attractive, environmentally sound

and energy efficient technologies can be developed for producing chemicals and materials.

Polymeric properties of these cellulosic materials should be investigated as well as the ability

to carry out the chemical modifications of these fractions into current and new products. The

lignin fraction yields two types of products with different molecular weight ranges. The high

molecular weight lignin fraction could be employed in a number of polymeric applications. A

possible commercial application for the low molecular weight lignin fraction is manufacturing

anthraquinone, described in section 8.4.

Acetylated wood. The inclusion of this technology as a near-term opportunity is based on the

results of the detailed technoeconomic evaluation of the process described in section 5.4, that

showed acetylated wood to be an inexpensive way to upgrade lignocellulosic biomass to a useful

product Wood acetylation imparts significant improvements in properties on wood fibers and

waste fibers. The costs of wood acetylation appear to be acceptable for use in composite

products, principally if the starting fibers have low cost, as is the case with wood waste,

recycled fibers, and agricultural residues. There remains to be demonstrated in longer term

testing that the compatibility of the acetylated wood fibers with the other components of

composites is acceptable and reproducible. '

The process appears to fulfill the criterion of broad potential scope. Although there has been

an interest in the United States in government, universities, and industry, only in Japan are

substantial inroads being made into starting the testing required for commercialization. For

instance, Daiken Trade and Industry Co., Ltd. is beginning to commercialize acetylated wood

under the name of a-wood for a number of higher value applications such as flat plate for large

speaker systems, bath tubs and bathroom doors, kitchen applications, and wood plastic

composites for heavy traffic walkways.

Whether additional substantial niche markets can be found remains to be seen; this marketdriven research is largely in the hands of the private sector, but there may be an opportunity

for a government-industry partnership in this area for acetylated wood, or perhaps, the

broader area of chemical modification of wood with other chemical derivatives, from which a

number of market niches or higher volume markets could be developed. It is necessary to

217
continue to assess the raw materials contribution costs of the other chemical modifications and

to establish appropriate areas for future partnerships.

4. Starch plastics. This technology was also included because of the results of the more detailed

economic projections of section 5.4. These are materials that could find use in producing

biodegradable plastic packaging or other applications. Further evaluation of their production

will be important, especially where chemical modification is used to impart specific

properties.

We analyzed one case developed at Michigan Biotech for certain plastics packaging that

combines synthetic plastics (ARCO's Dylark Resins) and inexpensive starch. It is an area that

has significant industrial and university research. The concept analyzed is deemed Promising

and should be verified at a larger scale so that the properties of the end-use Products can be

assessed more completely.

It is also necessary to continue screening a number of other starch chemicals and polymers to

uncover the most effective options for continued RD&:D. ReCentcommercial developments using

starch-based plastics confirm that the area is poised for additional Product development.

5. Fast pyrolysis of wood. Replacing phenol with pyrolysis phenolics is undergoing engineering

development and demonstration with industry. It shows a significant promise at the screening

level and at the more detailed flow sheet level. It also shows significant industrial interest

with the activities of the Pyrolysis Materials Research Consortium and the various companies

dedicated to fast pyrolysis worldwide. The field is poised for engineering development and

demonstration.

If the biomass pyrolysis refinery concept is to be developed to a significant industry, it is

important to obtain higher yields of products from all fractions, just like the oil industry

achieves use of more than 90% of its starting feedstocks.

A modification of fast pyrolysis for producing a high quantity of the oxygenated monomer

levoglucosan looks extremely promising (section 8.5). The process modification from the

conventional pyrolysis for phenolics has the potential to make two types of high volume

chemicals that should be explored. The phenolics from the process modified route have not

been assessed to the same level as those from straight pyrolysis. This modification should be

examined further because it could lead to product diversification and use of of the

feedstock instead of ~25%.

6. Wood Phenolation. The process involves the reaction of phenol and wood in the Presence of

sulfuric acid catalyst to liquefy wood. The neutralized oil is distilled to recover the product

and some recycled phenolics that can be used along with more phenol to liquefy wood. Research

in Japan at Kyoto University explores wood phenolation (and a number of other wood chemical

modifications) for use in replacing phenol in phenol-formaldehyde thermosetting resins.

Testing is proceeding at that University and with industry on products that can be made from

this process. Replacing black shellac (insect derived plastic material) has been studied.

Thermosetting resins prepared by this process have been reported to have excellent product

performance, perhaps superior to conventional phenol-formaldehyde formulations.

7. Benzene, Toluene, Xylene &om Wood: The process has a good potential for competing with

conventional sources, based on the raw materials cost ratio of 0.97 (section 5.1.3) and the level of

knowledge of how the process performs. However, at present, the U. S. markets for these

chemicals are not expected to increase.

218
8.

This process could be developed in countries and regions that need these chemicals and cannot

import or produce them. It is a process option that needs to be developed and that could be very

valuable for countries without major petroleum resources, but with significant biomass resources,

and with a plastics industry in infancyor early development.

The U.S. can continue to participate in this type of technology development by sharing the

intellectual property and knowhow accumulated over years of RD&D. The government

investment could be leveraged by appropriate partnership with other countries through which

the learned joint development results would become available to the US.. The technology

might be needed in the United States when oil prices increase substantially, and principally if

continued coal technologies development meet with environmental constraints that cannot be

sunnolDlted.

Acrylic Add. A combination of bioprocessing and chemical processing produces acrylic acid.

Lactic acid produced by fermentation of a starch waste (e.g., potato waste) can be esterified and

catalytically dehydrated into the corresponding low boiling point acrylate ester. By

hydrolysis, the acid is recovered and the alcohol used in the esterification can be recycled into

. the process. The raw materials cost ratio for this process was 1.47, for a process starting with

potato waste. The chemistry and process perfonnance of this technology has been investigated

by workers at PNL and appears to be an interesting way for processing potato wastes. However,

the economics need to be more carefully evaluated as a function of the cost of the potato waste,

currently assumed to be negligible. "Zero value" waste materials necessarily rise to their

market value when a use is discovered, and the effect of such a price increase on the ratio is not

yet known (see discussion in section 3.0).

8.4 MidTmn Opportunities

The evaluation process identified several possible RD&D opportunities that fall into the mid-term

time frame. These are generally processes or products that require some additional research and

development to improve market acceptability or process economics. They are likely candidates for the

next generation of products for the program. The bioprocessing target has been identified as butanol, an

example of a neutral solvent. For thermal and chemical processes, two potential candidates were

identified, anthraquinone and peracetic acid. Additional thermal and chemical examples are

identified here and additional bioprocessing opportunities are discussed in sections 6.0 and 7.0, and

specifically in Table 7.5.

1. Butanol. The secondary process evaluation indicated some economic uncertainty in the proposed

butanol process. This, combined with insight from the industrial panel, indicated that butanol

production should be considered a secondary priority because of limited funds and should be

reexamined for mid-term research needs. These needs should focus on the improvement of

yields and rates both by genetic manipulation and by simultaneous fermentation and

separation. Extraction should be emphasized as the separation technology to be developed.

Feedstock flexibility is another key mid-term issue.

2. Xylose, xylitol, furfural, tetrahydrofuran, glucose, gluconic acid, sorbitol, mannitol, levulinic

acid, and succinic acid. Each of these materials, derived from glucose, could have greater

importance as products in their own right, or as starting materials for other chemicals as a

result of the advent of the clean fractionation process. These materials are examples of the

"cascade" effect that could result from successful development of an efficient clean fractionation

process. RD&D into new uses of these materials would help establish their position as viable

feedstocks. Processes exhibit favorable raw materials cost ratios as high as 2.56 (xylose).

3. Anthraquinone. This process uses low-molecular-weight lignins that are converted to

anthraquinones by a two step chemical process. The laboratory research (NREL and the

219
Institute of Paper Science and Technology) results indicate that the amortized production costs

would be lower than all conventional processes published in the patent and open literature.

This is a high value chemical with the potential to reduce the need for sulfur-pulping

chemicals, increase the capacity of conventional kraft pulping thus helping the current

industry, and eventually replace some of the mills in which environmental compliance could be

more expensive than operation as a soda-AQ pulping in a retrofitted mode. Significant resource

and energy savings are accrued by virtue of the higher yield. Additionally, because pulping

can be carried out to a higher extent of delignification, bleaching chemicals requirements are

lower. Producing this chemical in the United States could recapture a market from imports and

the industry could become a significant exporter of catalysts to other countries.

An evaluation of this process gives a very favorable raw material cost ratio of up to 2.57,

depending on the source of lignin used as the starting material. It falls more into the mid-term

category because the research to date has been performed on a small laboratory scale. The

process appears viable at this scale, but larger scale experimentation is necessary to verify

these observations.

Recommended research includes screening process improvements and engineering scaleup of the

best conditions to date. The parallel development of the best chemical process with the

production of 100-500 g of pulping catalyst could allow its testing under "real world" pulping

conditions. The process should be scaled up with industry if the results above justify the

continued RD&Dinvestment.

4. Butadiene and PentaneJPentenes from Wood. This process involves biomass fast pyrolysis

followed by catalytic upgrading on zeolite-type catalysts. To date, the yields obtained from

wood are not high enough to justify their cost-effectiveness (the ratio for butadiene is 0.47 and

for pentanes/pentenes is 0.43). However, if the feedstock is changed from wood into refusederived fuel from municipal solid waste, the route becomes an importantroute for producing four

and five carbon hydrocarbons because of the much lower cost of the feedstock. Also, continued

development of appropriate catalysts may increase the yield and thus decrease the costs of

production.

5. Acetic acid can be produced from syn gas, a route that appears to be an interesting match given

the unique composition of synthesis gas available from biomass, and makes possible a balanced

process (through intermediate methanol) without the costs of syn gas reforming. The lack of a

reforming step can decrease capital costs significantly.

6. Peracetic acid: This oxidant is a good non-chlorine containing pulp bleaching agent. Its high

cost is the key impediment to a more widespread use. Alternative routes to peracetic acid

through biomass-derived chemicals may offer lower costs. They require innovative separations

solutions as well as the development of cost-effective oxidation processes. Using inexpensive

lactic acid (or acetaldehyde) as a starting material could be a good way to decrease the cost of

this chemical.

8.SLong Term Opportunities

Long-term RD&D opportunities can also be suggested at this time. Several interesting candidates were

noted during the analysis process as having potential promise. They are generally characterized as

needing Significant RD&Dprior to developmental considerations as potential product lines.

1. Levoglucosan. This material can be prepared from fast pyrolysis of biomass and is a complex

starting material for producing high value materials and specialty polymers. A specific

levoglucosan derivative is resorcinol, a cold setting adhesive that would find additional

220
markets at lower cost. Markets for these products will be developed as current research

emphasis in Japan, Canada, and the United States increases.

As this anhydro sugar becomes available from fast pyrolysis markets for its use need to be

developed. Chemically, it can be the source of a number of useful chemicals and materials. The

companion product, the unsaturated levoglucosenone, can also be obtained from cellulose or wood

pyrolysis. Recent progress on biomass fast pyrolysis will enable the monomers to become

available at very low cost. This inexpensive feedstock needs to be developed into products for

this part of the biomass refinery to achieve as high a volume as the phenolic applications.

Polymeric products with a high degree of chirality and special properties can be and are being

developed.

2. Vinylphenol: This high-value specialty monomer used in coatings and microlithography can be

made from biomass pyrolysis. With suitable biomass feedstocks, NREL research has shown

that significant yields of this monomer can be produced. Technoeconomic projections for this

process reveal a raw material cost ratio of 7.4, one of the highest calculated for any of the

chemicals in the portfolio. However, process parameters for vinyl phenol production are not

clearly defined, thus resulting in categorization of this material as a long-term opportunity. If

this monomer can be isolated and purified, it could transcend the specialty area and become a

precursor to biodegradable polystyrenes and other styrenic plastics. It should be explored both

from the viewpoint of selecting the biomass tyPe for higher yields of this product to improving

the pyrolysis and separation processes. The process needs to be validated.

3. Hydroxyacetaldehyde. This material is a by-product of fast pyrolysis of wood, that could be a

replacement for glyoxal as a crosslinking agent for resins. The raw material cost ratio,

comparing hydroxyacetaldehyde to glyoxal, is calculated at 1.25. However, a process for

separating the product needs to be developed to verify that this material could be produced

efficiently from biomass.

4. Polyhydroxybutyrate/valerate. This material, prepared directly from syn gas or from glucose

and propionic acid, could be important as a new biodegradable polymer with valuable

properties for a variety of applications, but is included as a long-tenn opportunity because the

data are not yet available at the level necessary to conduct a more detailed preliminary

technoeconomic assessment. The final answer to the critical question - whether syn gas would

be a cheaper precursor for a biological process than glucose - remains unanswered with data

available. The preliminary assessment indicates that the syn gas route is less expensive based

only. on raw materials costs. The glucose plastics manufactured to date are indeed more

expensive than equivalent polyesters. It is possible that if the raw materials cost contributions

are reasonable and a simple engineering is achieved, that the syn gas derived polyesters could

become more cost effective. Significant research, engineering, and development are necessary to

demonstrate this concept.

8.6Recommendations in Other DOE Program Areas and in Other Federal Agencies

One of the goals of this report is identifying potential RD&:D roles for different offices within DOE.

This information is intended to help determine the most appropriate use of RD&D funding to move the

Alternative Feedstocks program forward. Also listed in this section are RD&D opportunities not

directly linked to an evaluated chemical or process, but whose followup could provide important

information to the program as a whole.

Note that some opportunities overlap different offices. This overlap results from recommended

chemicals or processes that are made up of a mix of near-, mid-, and long-term research components. A

schematic summary of these recommendations is given in Figure 8.3. This figure is a sketch of the past,

current, and potential research and development efforts that have bearing on the use of alternative

221
Figure 8.3 • Coordination of research and development opportunities across federal agencies

..,

DOE Basic Energy Sciences Advanced Industrial Separations Division Office of Waste Reduction Other DOE offices and federal agency

(BES) and the National Science Concepts Division (AICO) (SO) (OWR) efforts complementing AFP efforts

Foundation (NSF)

Biological and Chemical AFP, PUlp& Paper, Waste Utilization U.S. Dept. of DOE office or federal

Technologies Research Separations Conversion (WUC) Agriculture agency

(BCTR)

Identifying and isolating new Separation processes research Design for recycle of Citrus

products from wood for bioprocesses - N products from wastes wastes to

pyrolysis processes· N (see (Separations) (wood, plastics, etc) - N chemicals -

WOC) 0

Metabolic and genetic Microbial PHB/V Microbial PHB/V from

engineering of new organisms - (polyhydroxybutyrate valerate) syngas - R

0 from COzor syngas - P

Engineering enzymes and Expanding the portfolio of Isolating new products Enzymes in organic

biocatalysts for potential commercial from fast pyrolysis solvents - DOE Fossil

unnatural/extreme products - 0 (AFP -see technologies - 0 & N Energy - 0

environments - 0 (see Other) BCfR)

Developing new chemical and Modeling biocatalysts, Developing bioprocessing for Simultaneous

biocatalysts, including including biomimetic organic acids - 0 (AFP) Saccharification

biomimetic catalysts - 0 catalysts, for industrial Fennentation RD&D- 0

applications - 0 (Office of Transportation

Technologies - orr/

Biofuels)

New methods for transferring Metabolic and genetic Providing industry with Sequencing various large

genetic information between engineering of industrial capabilities for a broad swing genomes provide methods

organisms - 0 bioprocesses including strict of products - N (AFP) for transferring genetic

Understanding genetic control anaerobic systems - 0 information - 0 (DOE, NIH,

of microbial metabolism - 0 Overcoming instabilities in NSF)

genetically engineered

microbial cultures - R

Bioreactor design and operation Bioreactor design for Implementing bioreactor

-0 continuous operation, design in pilot scale operation

reducing product feedback - 0 (AFP)

inhibition, and increasing

conversion rates (organic

acids, neutral solvents, etc.) -

R&O

Key: 0 =Ongoing or currently supported work in thisarea; P =preliminary ongoing or currently supported work; N =New opportunity for research or R&D; R =Previous work in

this area; LCS - Lignocellulosics; RN - Renewables

. j
I'lgure 0..1 - conunuea

DOE Basic Advanced Industrial Concepts Division Separations Division Office of Waste Reduction Other DOE offices and federal

Energy (AICD) (SO) (OWR) agency efforts complementing

Sciences AFP efforts

(BES) and

the

National Biological and Chemical Materials (AIM) AFP, Pulp & Paper, Waste Industrial Waste Municipal U.S. Dept. of DOE office or

Science Technologies Research Separations Utilization Reduction Solid Waste Agriculture federal agency

Foundation (BCTR) Conversion (IWRPj (MSW)

(NSF) (WUC)

Catalysts Catalyst models and Developing Hydroxyacet- AARC Fennentable

for LCS - N catalyst testing for LCS bioprocessing for neutral aldehyde from initiative sugars from

(see BCTR) derived feedstocks - N solvents - 0 (AFP) wood development clean fractions

(see BES/NSF) pyrolysis - N opportunities of cellulose

and hemicellulose - P

(Orr/Biofuels)

Clean fractionation for Acetylated or Anthraquinone and other Lactic acid Acetic acid from Uses for

cellulose, lignin, modified wood - sulfur free pulping from syngas - 0 starch:

hemiceJIulose - R & N P&R catalysts - R & N renew abies - plastics, etc.

(Pulp/paper) 0 -0

Photo- Clean fractionation to Bio & chemical Developing chemica I Photo- Total life-cycle Butadiene Benzene,

synthesis new products (xylose, processing for processes for producing synthesis energy/ environ- and C5 toluene, xylene

research to glucose, gluconic acid, new rnateriaIs or cellulose/lignin/hemi- Research for mental costs for chemicals from wood M N

enhance sorbitol, etc.) - N uses of current cellulose feedstocks for crop commodities - from (viz. Techn,

energy crop materials: starch, chemicals and materials productivity - o (can use municipal development in

productivit plastics, etc. - R (cellulose acetate, etc.) - 0 AFP/BCTR solid waste third world

y-O &N o (AFP) data) streams - N countries

(see BCTR) through U.S.

Agency for

International

Development)

Catalysts for butadiene, Peracetic acid - N Pyrolysis of High solids Developing Dedicated

C5 compounds « N (see (Pulp / paper) wood wastes anaerobic energy crops feedstock

OWR/MSW) to chemicals M digestors - -0 supplies - 0

0 0 (Orr/Biofuels)

Levoglucosan monomers Acetylated wood - N Levoglucosan Controlled

for polymers - P production - environmental

N (see BCTR) agriculture - 0

(NASA)

Key: 0 =011going or currently supported work in this area; P "" preliminary ongoing or currently supported work; N =Newopportunity forresearch or R&D; R "" Previous work in

thi« area; Les - Lignocellulosics; RN - Renewables

223
Figure 8.3 • continued

DOE Basic Energy Advanced Industrial Concepts Separations Division Office of Waste Reduction Other DOE offices and federal

Sciences (BES) and the Division (AICD) (SO) (OWR) agency efforts complementing

National Science AFP efforts

Foundation (NSF) Biologicaland Chemical AFP, Pulp & Paper, Waste Industrial Waste U.S. Dept. of DOE officeor federal

Technologies Research (BCTR) Separations Utilization Reduction Agriculture agency

Conversion (IWRP)

(WUC)

Developing uses of vinyl phenol Vinyl phenol

as a feedstock - N from bagasse -

0

New chemistries for use of New uses of carbohydrates Integration of RN into existing CO2 and syngas: New uses of Protein engineering

carbohydrates for derived from renewables for processes - N (AFP) feedstocks for carbohydrates for new materials - R

synthesis - 0 polymers, reagents, etc. - N alcohols & other for polymers, (U.S. Army Res.)

chemicals - 0 & reagents, etc. -

N O&N

Databases for potential new Databases for potential new Acrylic Acid Processing of LCS

products from RN - 0 (AFP products from RN - 0 (AFP) from food for fermentation

activity should be augmented with wastes - N processes - 0 - BCfR work) Data bases of (OTT/Biofuels)

pretreatment options - 0

Analytical tools for Analytical tools for assaying RN Acrylic acid from waste LCScharacterization

assaying RN proce~ses - N processes - N streams - N standards - 0

(OTT/Biofuels)

Novel processing of fermentation LCScharac- LCS preparation for

broths for "product-by-design" - P terization processing - 0

standards - 0 (OTT/Biofuels)

Reverse chemical complexation to Electrodialysis, extraction, LCS prepreduce energy consumption in pervaporation for isolating aration for

isolating fermentation products - fermentation products - 0 thermal &

0 (AFP) biological processing - 0

CO2 as a feedstock for CO2 as a feedstock for chemicals

fuels production - 0 production - 0 & N

For AFP, BCTR, IWRP, WUC programs: R&D in the development of better integrated decision maldng models. Would combine ongoing work in BCTR, AFP, IWRP, and WUC

programs to take into account technical, economic, and environmental processing factors. Would be of value to industry. Can employ model development pursued by DOE's

environmental restoration programs.

Key: 0 =Ongoing orcurren~y supported work in this area; P=preliminary on~ .tJrrenllysupported work;N= New opportunity for research orR&D; R= Previous work in this area; LCS · Lignocs/lulosics; RN · Renewables
' j

feedstocks in the production of chemicals. The organization of the figure is intended to convey an

ongoing and continuous process that progresses from early research findings, to bench scale

demonstrations of technology, followed by precommercialization RD&D. The last two columns of

Figure 8.3 show relationships to other DOE offices and federal agencies that complement the

Alternative Feedstocks program. The examples depicted there range from basic research findings to

precommercialization efforts. Defining the potential interactions between other DOE offices and other

federal agencies will be included in future updates of this report.

8.7Timeframe for Completion

The initial emphasis of the Alternative Feedstocks program has been on the evaluation of the

potential and economic opportunity of biobased products. This ongoing product/process screen is

supplemented by surveys on feedstock availability, market potential, improved pathways, and

advanced chemical, thermal and bioprocessing concepts. Literature surveys and evaluations have been

done in consultation with an industrial panel.

The program will take basic concepts, initiated under other programs, which show potential of

T: marketability for biobased products. These concepts will be economically evaluated to estimate the

impact. The best concepts for the target compounds will generally be taken directly to the

developmental stages. Industrial involvement will be actively sought in the early phases of the

development efforts. Often, it will be apparent that additional research is necessary to utilize the

process. Research support will be sought from other DOE offices or other federal agencies to address

these research issues.

A laboratory demonstration of the process components will be performed for the target compound. This

work may be carried out at various sites. Results from this demonstration will be used to design a

complete demonstration unit for testing. The results will also be used to refine the economic model. It is

expected that industrial participant(s) will have an increased role at each stage of development. The

final stage will be a pilot plant constructed through cost-sharing with the industrial participant.

Projects in the program will be market driven. However much of the RD&D may have generic

applicability to an entire class of materials, such as improved separation for organic acids or improved

pretreatment of lignocellulosics. The projects will tend to focus on the actual developmental

demonstration and economic evaluation of real products and processes. Near-term projects are

preferred, with an impact seen in 1 to 5 years; but mid-term (5 to 10 years) projects may also be

considered. For a project, advanced techniques will be employed when they enhance process economics.

A typical time frame for demonstration and commercialization is shown in Figure 8.4.

Aclivitv Y.,.l y.,z Year3 y.,4 y.,s y." y." Yar8 I Year' YarUI

Feedstock Se1ecrioo aod PImeaIman Developrneat :

CaIa1yst SelectionandRefinement I

ReacrorDevelopment I I I

ReaJvery and Purificuioo Development I I I !

I ! : EffloeotTrc:aanent

I I

SmaU-Scale Wegnrion

I I Pilot-Scale Demoasttal:ion i :

I I I :

Engineering-Scale Demonstration

ProcessEngineering & Ec::onomia I I I I

Commen:iaJ UnitStan-Up I I I I

I ....

Figure 8.4 - Typical Demonstration and Commercialization Time Frame

225
9.0 REFERENCES AND SELECTED BmUOGRAPHY

General Documents and References

1)

2)

3)

4)

5)

6)

7)

. , 8)

9)

10)

11)

12)

13)

"Symposium on Levoglucosan and Levoglucosenone", Abstracts of the 204th National Meeting of

the American Chemical Society, Washington, D. C., 1992.

I'Annual Energy Outlook 1992 with Projections to 2010", Energy Information Administration,

U.S. Department of Energy, publication number OOE/EIA-D383(92).

A. D. Little, "Technical and Economic Feasibility of Enzyme Hydrolysis for Ethanol Production

from Wood", Arthur D. Little, Inc., Cambridge, MA, 1985.

Technical Insights, Inc, 1980,''Biomass Process Handbook - A Production/Economic Guide to 40

Chemical Processes that use Biomass as a Raw Material; Fort Lee, NJ·

Stone and Webster Engineering, "Economic Feasibility Study of an Enzyme-based Ethanol

Plant", SERI/STR-231-3138, Solar Energy Research Institute, Golden, CO,1987.

"Pulp and Paper 1992 North American Factbook", Miller Freeman Inc., San Francisco, 1991.

U.S. Department of Commerce, International Trade Administrative, U.S. Industrial Outlook

1992, Chapter 11,1992 .

Browning, B. L., ed., "The Chemistry of Wood", New York: Interscience,1963.

Browning, B.L, "Methods of Wood Chemistry", Vol. I and Il, New York: Interscience, 1%7.

Kollman, F. F. P., and W. A. Cote, Jr., "Principles of Wood Science and Technology," Vol. I,

New York: Springer-Verlag, 1968.

Panshin, A., and J. C. de Zeeuw, "Textbook of Wood Technology", 4th edition, New York:

McGraw-Hill, 1980.

Rydholm, S. A., "Pulping Processes", New York: Interscience,1965.

Sarkanen, K. V., and C. H. Ludwig, editors, "Lignin: .Occurrence, Formation, Structure and

Reactions", New York: Wiley-Interscience,1971.

GeneralReferences Used inCompiling MarketInfmmation

1) Kirk-othmer Encyclopedia of Chemical Technology,3rd ed., John Wiley, New York, 1984.

2) Chemical Economics Handbook, SRI International, Menlo Park, CA, 1992.

3) Ullmann's Encyclopedia of Industrial Otemistry,5th ed., VCH, Weinheim, 1986

Other R.eferences

1) :J 2)

3)

4)

5)

6)

7)

8)

9)

10)

11)

12)

Amcultural Statistics, ·(1991), Washington, D.C.: USDA.

IIAgriculture 2000: A Look at the Future", Richland, WA: Columbus Division of Battelle

Memorial Institute, Battelle Press, (1983).

Almosnino, A. M., and J. M. Belin, Biotechnol. Lett.. 199113,893.

Andrews, G., Biotech. Bioen~n.. 1989, 33, 256.

Amheim, N., and CR. Levenson, Chemical & Engineering News, October 1, 1990,35.

Ausich, R., F. Brinkhuis, M. Donnelly, L. Hardin, E. Hatch, W. Hunsaker, L. Hunt, J. Kauth, I.

Mukharji, M. Ratag, and B.Yen, "Production of Carotenoids by Recombinant DNA Technology",

Society of Industrial Microbiology Annual Meeting, San Diego, CA, August 1992.

Battelle Memorial Institute, IIAgriculture 2000: A Look at the Future", Battelle Press,

Columbus/Richland, Washington (1983).

Bergez, J.-E., L. Bouvarel, and D. Auclair, Biores. Techno!. ,1991,35,41.

Berglund, K. A., et al., U.S. Patent 5,034,105 (1991).

"Biomarkets: 43 Market Forecasts for Key Product Areas", Fort Lee, NJ: Technical Insights,

Inc., (1991).

Bond, G.E., in "Competitiveness of the U.S. Chemical Industry in International Markets",

AIChE Symposium Series 274, (1990).

Bridgwater,A. V., J. Kuester, Eds. "Research in Thermochemical Biomass Conversion",

Elsevier Applied Science: London, 1988;and references therein.

227
13) Bruce, L. J., and A. J. Daugulis, Biotechnol. Pro&., 1991, 7, 116.

14) Busche, R. M., in "Biotechnology: Applications and Research", Lancaster, PA: Technomic

Publishing, Inc., chapter 9 (1985). _

15) Busche, R. M., "Technoeconomic Evaluation of the Extractive Fermentation of Butanol",

ORNL/TM Report #11851, Oak Ridge, 'IN: Oak Ridge National Laboratory (1991); Busche, R.

M., and B. R. Allen, &wI. Bicxhem. Biotechnol., 1989,20121,357-374.

16) Chemical and Engineering News, June 29, 1992.

17) Chemical Marketing Rgporter , July 24, 1992.

18) Chum, H. L, S. K. Parker, D. A. Feinberg, J. D. Wright, P. A. Rice, S. A. Sinclair, and

W. G. Glasser, May 1985, "The Economic Contribution of Lignins to Ethanol Production from

Biomass", SERI/TR-231-2488, Golden, CO: Solar Energy Research Institute.

19) Chum, H L., L. J. Douglas, D. A Feinberg, and H. A Schroeder, SERI/TR 231-2183 (1985)

20) Chum, H. L, J. P. Diebold, J. W. Scahill, D. K. Johnson, S. Black, H A. Schroeder, and R.

I<reibich, 1989, in "Adhesives from Renewable Resources", R Hemingway and A. Conner, Eds.,

ACS Symp. Series, 135-151.

21) Chum, H. L., editor, "Assessment of Biobased Materials", SERI/TR-234-3610, Solar Energy

Research Institute, Golden, CO, 1989,Chapter 2 and references therein.

22) Chum, H. L, J. P. Diebold, S.K. Black, J.W. Scahill, D.K. Johnson, and RJ. Evans "Inexpensive

Phenol Replacements from Biomass" Energy from Biomass and Wastes XV, Washington, D.C.,

March 25-29,1991.

23) Chum, H. L . and S. K. Black, US. Patent 4,942,269, (1990),

24) Cohen, J. C (ed.), "Topicsin Molecular and Structural Biology", p. 12 (1989).

25) Compere, A. L, and W. L Griffith, Dev. Ind. Microbiol..l976, 17,247-52.

26) "Com Annual", Com Refiners Association, Inc., (1992).

27) Cselovszky, J" et aI., AWl. Microbiol. Biotechnol., 1992, 37,94.

28) Datta, R., "Technological Advances and Needs for Large Scale Bioprocessing and Separations,"

presented at National Com Utilization Conference, St. Louis, MO, June 24-26, 1992.

29) Datta, R., U.S. Patent 4,885,247 (1989).

30) Datta, R. et aI., Eur. Patent Appl. EP 405707 (1991).

31) Davison, B. H. and J.E. Thompson, AWl. Bicxhem. Biotech., 1992, 34135,431.

32) Davison, B. H. and C.D. Scott, AWl. Bicxhem. Biotech.. 1988, 18, 19.

33) Davison, B. H. and C. D. Scott, Biotech. Bioengr.. I992, 39,365.

34) Davison, B. H ., and J. E. Thompson, AWl. Bicxhem. Bioteehnol.. in press.

35) Diebold, J. P.and A J. Power, 1988, "Research In Thermochemical Biomass Conversion", A V.

Bridgwater and J. Kuester Eds., London: Elsevier Applied Science, pp. 609-628.

36) Diebold, J. P. and J. W. Scahill, 1988, in "Pyrolysis Oils from Biomass - Producing, Analyzin~,

and Upgrading", E.Soltes and T. Milne, Eds., ACS Symp. Series, 376,21-28; Diebold,J. P. and j .

W. Scahill, 1988, ibid.. 31-40.

37) Diebold, J., in "Biomass Pyrolysis Uquids Upgrading and Utilisation", AV. Bridgwater and G.

Grassi, eds., Elsevier Applied Science, 1991, pp. 341-351.

38) Dower, W. J., "Genetic Engineering", J.K. Setlow, ed., p. 12, (1990).

39) Eckert, G., and K. Schugerl, AWl. Microbiol Biotechnol.. 1987,27,221.

40) EG&tG Idaho, Inc" "Assessment of Biomass as an Alternate Energy Source", Idaho National

Engineering Laboratory, Idaho Falls, Idaho (1981).

41) Elliott, D.C., D. Beckman, A.V. Bridgwater, J.P. Diebold, S.B. Gevert, and Y. Solantausta,

EnerlY and Fuels, 1991,5. .

42) Elshafei, A. M., J. L. Vega, K. T. Klasson, E. C. Clausen, and J. L Gaddy, Biores. TechnoI., 1991,

35,73.

43) Electric Power Research Institute, "Biomass State-of-the-Art Assessment", Research Triangle

Institute, Research Triangle Park, NC (1991).

44) "Encyclopedia of Chemical Technology", 3rd ed., (1982),New York, NY: John Wiley and Sons.

45) Ennis, B. M., N. Qureshi, and I. S. Maddox, Enzyme Microb. Technol.. 1987, 9, 672.

46) Evans, P.J. and H. Y. Wang, Appl. Microbiol. Biotechnol.. 1990 ,32,393.

47) Evans, P.J. and H. Y. Wang, Appl. Environ. Microbiol.. 1988, 54, 1662.

228
51>

52)

53)

54)

55)

, '

<- .." 56) {.::_';

57)

58)

59)

60>

61)

- 62)

63)

64)

65)

66)

67)

68)

69)

70)

71)

72)

73)

74)

75)

76)

77)

78)

79)

80>

48) Evans, R. J. and T. A. Milne, 19~, in "Pyrolysis Oils fro~ Biomass - Producing, Analyzing, and

Upgrading", E. Soltes and T. Milne, Eds., ACS Symp. Series, 376, 311-327.

49) Evans, R. J., T. A. Milne, in "Research in Thermochemical Biomass Conversion", Bridgwater, A.

V.; Kuester, J., Eds., London: Elsevier Applied Science, 1988; p 264.

50) Evans, R. J. and T. A. Milne, "Energy from Biomass and Wastes XI", D. Klass, Ed., Chicago:

Institute of Gas Technology, pp. 807-838, 1988; Evans, R. J. and T. A. Milne, "Research in

Thermochemical Biomass Conversion", A. V. Bridgwater and J. Kuester, Eds., London: Elsevier

Applied Science, pp. 264-219, 1988.

Frank, J.R., in 'lfossil Energy Biotechnology: A Research Needs Assessment Final Report",

W.R. Finnerty, ed., OOE Contract 01-91 ER30156, Washington, DC: U.s. Department of Energy,

chapter 8, (1992).

Frank, J.R, and W.H. Smith, in "Methane from Biomass: A Systems Approach", W.H. Smith

and J.R Frank (eds.) London: Elsevier Applied Science (1988).

Friedl, A., N. Qureshi, and I.S. Maddox, Biotechnol. Bioenp-., 1991,38,518.

Gaillot, F. P., C. Gleason, J. J. Wilson, and J. Zwarick, Biotechnol. Prog.. 1990, 6, 370.

Ghose, T. K. and A. Bhadra., in "'Comprehensive Biotechnology", M. Moo-Young (ed.), New

York, NY: Pergamon, chapter 38 (1985).

Glassner, D., and R. Datta, Eur. Pat. AppI. 0393 818 (1990).

Glassner, D., and R. Datta, Eur. Pat. Appl. 0389 103(1990).

Gottschalk, G. and H. Grupe in "Harnessing Biotechnology for the 21st Century", Ladish, M. R.

and A. Bose, (eds.), Washington, D.C.: American Chemical Society, 102 (1992).

Graham, R. G., B. A. Freel, and M. Bergougnou, in '~esearch in Thermochemical Biomass

Conversion", A. V. Bridgwater and J. Kuester, Eds., London: Elsevier Applied Science, pp. 1988,

pp. 629-641.

Groot, W. J., RG.},M. van der Lans, and K. Ol. A.M. Luyben, Process Biochern., 1992,27, 61.

Gruy Engineering Corporation, "Estimates of RCRA Reauthorization 'Economic Impacts on the

Petroleum Industry", prepared for American Petroleum Institute, July 20, 1991.

Hawaii Sugar Planters' Association, "Hawaii Sugar Manual 19911

' , ISSN 1048-9428.

Hickey, RF. and RW. Owens, Biotech. Bioeng. Symp. Ser., 1981,399.

Hollberg, P.O., T.}.Woods, M.L. Lihn, and N.C. McCabe, in "Gas Research Insights" (991).

Hogan, E. N., Ed., Proc. 7th Canadian Bioenergy Seminar, National Research Council of

Canada: Ottawa, Ontario, Canada, 1990, pp 669-720.

Hotta, K. and S. Takao, Hakko Kopku Zasshi. 1973, 51, 19.

HRA, Inc., "A Commercial and Technical Assessment of Lactic Acid, Selected Salts of Lactic

Acid, and Polylactic Acid", prepared for Argonne National Laboratory (1991).

Ingram, LO. et al., U.s. Patent 5,000,000 (1990).

Ishii,S., T. Masahito, and T. Kobayashi, T. Chern. Eng. Japan. 1985, 18, 125.

James, R. W., "Industrial Starches", Noyes Data Corp., Park Ridge, NJ, 1974.

Johnson; D. K., unpublished results at SERI, 1990.

Jones, D. T. and D. R.Woods, Microbiol. Rev.,1986,50, 484.

Jones, D. T. and D. R. Woods in "Clostridia", N. P. Minton and D. J. Clarke (eds.),Plenum Press,

105 (1989).

Kang, W., R. Shukla, and K. K. Sirkar"Biotech. Bioen~.. 1990 36,826.

Kertes, A. S. and C. J. King, Biotech. Bioeng., 1986,28, 269.

Klein, T. M., et al., Bio/Technology, 1992,10,286.

Ladisch, M. R., Enzyme Microb. Technol..l991, 13, 280.

Lee, A.K.K. and A.M. Aitans, Oil and Gas TournaI. September 10, 1990.

Leeper, S. A., J. H. Wolfram, M. L. Chow, and L. J. Dawley, "Municipal Solid Waste

Bioconversion Techniques", EG&G Idaho, Inc., Idaho National Engineering Laboratory, Idaho

Falls, Idaho (1982).

Leeper, S. A., T. E. Ward, and G. F. Andrews, "Production of Organic Chemicals via

Bioconversion: A Review of the Potential", EG&G Idaho, Inc., Idaho National Engineering

Laboratory, Idaho Falls, Idaho (1991).

229
81)

82)

83)

84)

85)

86)

87)

88)

89)

90)

91)

92)

93)

94)

95)

96)

97)

98)

99)

100)

101)

102)

104)

105)

106)

107)

108)

109)

110)

111)

112)

Levy, P. F., A. P. Leuschner, and J. H. Stoddart, Jr., "Biorefining of Selected Industrial Wastes

to Liquid Fuels and Organic Chemicals", Department of Energy, DOE/CE/40556-T2

(DE83013910) (1983).

Linden,J.C, A. R. Moreira, and T. G. Lenz, in "Comprehensive Biotechnology", M. Moo-Young,

(ed.), Oxford: Pergamon Press, chapter 44, 915-931 (1986).

Ung, L. B., and T. K. Ng" U. S. Patent 4877731 (1989).

Lipinsky, F. S. TaWi T. 1983, 66(10), 47.

List, H.L., "Petrochemical Technology: An Overview for Decision Makers in the International

Petrochemical Industry", Prentice-HaD, NJ (1986).

Lynd,L. R., J. H. Cushman, R. J. Nichols, C E.Wyman, Science, 1991, 251, 1320.

Manzoni, M., and V. Cavazzoni, 1.Chem. Tech. Biotechnol..I992, 54, 311.

Maiore1la, B. L. in "Comprehensive Biotechnology", vol. 3, M. Moo-Young, ed., Pergamon Press,

New York (1985).

Mermelstein, L. D., et aI.; Bio/Technolo~, 1992, 10,190.

Mok, W. 5., M. J. Antal, M. Jones, T. Om. Chern., 1989,54, 4596

Morris, D. and I. Ahmed, 1992, .. The Carbohydrate Economy - Making Chemicals and

Industrial Materials from Plant Matter," TIle Institute for Local Self Reliance, In press.

National Academy of Sciences, ''Putting Biotechnology to Work: Bioprocess Engineering",

Washington, D.C, National Academy of Sciences (1992).

Narayan, R., T. Kiessling, and G. T. Tsao, AWl. Biochem. BiotechnoI..1988, 17,45.

Oak Ridge National Laboratory (1992), L. L. Wright, personal communication.

Office of Technology Assessment, "Commercial Biotechnology: An International Analysis",

Congress of the United States, OTA-BA-218 (1984).

Office of Technology Assessment, "Agricultural Commodities as Industrial Raw Materials",

Congress of the United States,OTA-F-476 (May, 1991).

Office of Technblogy Assessment, "Biotechnology in a Global Economy", Congress of the United

States, SIN 052-003-01258-8 (1991) . II

Okada, H., et aI., I. Gen. AWl. Microbiol., 1961, 7, 177.

"Organic Chemicals From Biomass", D. L. Wise (ed.), Benjamin/Cummings Publ. Co. (1983).

Osten, J. and W. Veno, "US. Refining Model Methodology Report. Final Report". Ga

Research Institute Contract #5089-800-1796 (1991).

Overend, R. P., and H. L. Chum, BioIQ~e.1991,8, 10.

Overend, R. P., T. A. Milne; L. K. Mudge, Eds., "Fundamentals of Thermochemical Biomass

Conversion", Elsevier Applied Science: London, 1985.

Parker, S. 1<., M. Calnon, D. A. Feinberg, A. J. Power, and L. Weiss, 1983, "The Value of

Furfural/Ethanol Coproduction from Acid Hydrolysis Processes", TR-231-2000, Golden, CO

Solar Energy Research Institute.

Perlack, R.D., J. W. Ranney, and L L Wright, "Environmental Emissions and Socioeconomi ;

Considerations in the Production, Storage, and Transportation of Biomass Energy Feedstocks",

Oak Ridge National Laboratory, Report #ORNL/TM-12030 (1992).

Ransom, I<. M., Editor, "Markets 90-94. The Outlook for North American Forest Products",

Widman Management Ltd., Miller Freeman Publications, San Francisco, (1990).

Rejai, B., R. J. Evans, J. P. Diebold, and J. W. Scahill, in "Energy from Biomass and Wastes XV",

Washington, D.C, (March 25-29,1991).

Roffler, S. R., H. W. Blanch,and C R. Wilke, Biotech. Bioen&T., 1988, 31, 135.

Roffler, S. R., T. W. Randolph, D. A. Miller, H. W. Blanch, and J. M. Prausnitz, Chap 6 p. 133-

172 in "Extractive Bioconversions", B. Mattiasson and O. Holst, (eds.), New York, NY: Marcel

Dekker, Inc, chapter 6 (1991).

Roffler, S. R., H. W. Blanch and C R. Wilke, Biotechnol. Prog., 1987, 3, 131.

Roger, E.W., in "Competitiveness of the U.S. Chemical Industry in International Markets", J.J.

Ulbrect, AICHE Symposium Series, 1990 274, 86.

Rousseau, R. W. (ed.), "Handbook of Separation Process Technology", New York, NY: John

Wiley & SOns (1987).

230
113)

114)

115)

116)

117)

118)

119)

120)

121)

122)

123)

124) . 125)

126)

127)

128)

129)

130)

131)

132)

133)

134)

135)

136)

137)

138)

139)

140)

141)

142)

143)

144)

Rowell, R. M., T. P. Schulz, and R. Narayan, Editors, "Emerging Technologies for Materials and

Chemicals from Biomass", ACSSymposium Series, 476, (1992).

Roy, K. A., Hannat World. 1992 (Iuly), 32.

Russell, M., E. W. Colglazier, and B.E. Tonn, Environment. 1992, 34, 12-39.

Salunkhe, D. K., S. S. Kadam, and S. J. [adhav, "Potato: Production, Processing, and Products",

CRC Press, Boca Raton, Florida (1991).

Samuelov, N. S., et al., Appl. Env. Microbio1..1991, 57,3013.

Sato et al., Agr. BioI. Chern., 1972, 36, 1969.

Scott, D., J. Piskorz, and D. St. Radleinn in "Emerging Technologies for Chemicals and

Materials from Renewables", R. M. Rowell, T. P. Schultz, and R. Narayan, Editors, ACS

Symposium Series, 1992,476,422.

Shah, M. M., S.K. Song, Y.Y.Leeand R. Torget., AWl. Biochem. Biotechno1..1991, 28/29, 99.

Shiraishi, N. in "Lignin: Properties and Materials"; Glasser, W. G.; Sarkanen, S., Eds.; ACS

Symposium Series 1989, 397; 488. .

Shiraishi, N. I. AWl. Polym. Sci. 1986, 32, 3189.

Shiraishi, N., H. Ito, S. V. Lonikar, N. Tsujimoto, 1.Wood Chern. Technol.. 1987,7,405.

Shukla, R., W. Kang, and K. K. Sirkar, Biotech. Bioengr., 1989, 34, 1158.

Soltes, E., T. A. Milne, Eds., Pyrolysis Oils from Biomass - Producin&, Analyzin& and

Uwadin&: ACS Symposium Series 376; American Chemical Society: Washington, D.C., 1988.

Spitz, P. H., "Petrochemicals - The Rise of an Industry", Wiley, New York (1988).

Stavins, R. N., and B. W. Whitehead, Environment, 1992,34" 7.

Szmant, H. H., "Industrial Utilization of Renewable Resources", Technomic Publishing Co.,

Lancaster, (1986).

Szmant, H.H., "Organic Building Blocks of the Chemical Industry", New York, NY: John

Wiley & Sons (1989).

Takao, S., et al., Hakko Kopku Zasshi,1973, 51, 19.

Technical Insights, Inc., "Biomarkets: 43 Market Forecasts for Key Product Areas", Fort Lee,

New Jersey (1991).

Teunissen, M. J., and G. D. Vogels, "Cellulolytic and Xylanolytic Enzymes of Anaerobic Fungi."

Presented at 14th Symposium on Biotechnology for Fuels and Chemicals, Gatlinburg, Tennessee,

May 1992.

USDA, "Proceedings: Whey Products Conference", Eastern Regional Research Center,

Philadelphia, Pennsylvania (1980).

USDA, "New Farm and Forest Products: Responses to the Challenges and Opportunities Facing

American Agriculture", New Fann and Forest Products Task Force, Washington, D.C. (1987).

USDA, "Costs of Production - Major Field Crops, 1990", Economic Research Service, ECIFS 10-4

(1990).

USDA, "Agricultural Statistics", Washington, D.C. (1991).

USDA, "Oil Crops Situation and Outlook Report", Economic Research Service, OC5-32 (January

1992). .

USDA, "Feed Situation and Outlook Report", Commodity Economics Division, FDS-322 (May

1992).

USDA, "Agricultural Resources: Agricultural Land Values and Markets Situation and Outlook

Report", Economic Research Service, AR-26 (June 19913).

USDA, "Sugar and Sweetener Situation and Outlook Yearbook", Economic Research Service,

SSRVl7N20une 1992b).

USDA, "New Industrial Uses, New Markets for U.S. Crops: Status of Technology and

Commercial Adoption", Hudson and Harsch, Maumee, OH (October 1992).

USDA, "Agricultural Resources: Crop, Plant, Water, and Conservation Situation and Outlook

Report", Economic Research Service, AR-27 (September 1992).

U. S. Department of Energy, "Electricity from Biomass. National Biomass Power Program, Five

Year Plan 1994-98" (1993)

Vickroy, T. B., in "Comprehensive Biotechnology," vol. 3. New York, NY: Moo-Young, M.,

(ed.), Pergamon, chapter 38 (1985).

231
145) Wang, H. Y. and K. Sobnosky, ACS Symp. Ser..1985, 271, 123.

146) Wang, H. Y., F. M. Robinson, and S. S. Lee, BiQtech. Bioen~. Symp. Ser.•1981,11,555.

147) Wardell, J. M. and C. J. King, T. Chern. En~. Data, 1978, 23, 144.

148) Watson, S. A., and P. E. Ramstad, "Com: Chemistry and Technology", American Association of

Cereal Chemists, Inc. St. Paul, MN (1987).

149) Wayman, M., and R. Parekh, I. ferment. TechnQ!.. 1987, 65, 295.

150) Wayman, M., S. Chen, and K. Doan, Ptpc. Biochem., 1992, 27,239.

151> Wilks, H.M., et al. in 9th Proceedings of the International BiQtechnolQgy Symposium, 1992,

150.

152) Wright, L. L., J. H. Cushman, A. R. Ehrenshaft, S. B. Mclaughlin, W. A. McNabb, J. W. Ranney,

G. A. Tuskan, and A. F. Turhollow, "Biofuels Feedstock Development Program: Annual Progress

Report for 1991", Oak Ridge National Laboratory, Report #ORNL~742(1992).

153) Yergin, D., The Prize. New York; Simon &: Schuster, (1991).

232