# Technical Memorandum

To: National Bioenergy Center

Title: Technoeconomic Modeling to Support the EPA Notice of Proposed Rulemaking (NOPR)

Author: Ling Tao and Andy Aden

Platform: Process Analysis

Date: November 3 rd 

# , 2008

Abstract : Under the Interagency Agreement between the Environmental Protection Agency (EPA) and U.S. Department of Energy (DOE), a statement of work (SOW) was established to generate “Cellulosic Process and Cost Analysis”. Three biochemical technoeconomic scenarios have been developed for this work to date, corresponding to years 2010, 2015 and 2022. The material and energy balances contained in the report were generated usin g Aspen Plus models. Economic calculations are done by in house databank and tools in a spreadsheet framework. Using a disco unted cash flow rate of return analysis, the minimum ethanol selling prices (MESP) are $2.43, $1.33 and $1.21 per gal ethanol with respect to model 2010, 2015 and 2022.

Keywords: State of Technology, Emission, Cost, Design Report, Ethanol, Biochemical, EPA, MESP

Background:

Under the Interagency Agreement between the Environmental Protection Agency (EPA) and U.S. Department of Energy (DOE), a statement of work (SOW) was established to generate “Cellulosic Process and Cost Analysis”. Task 1 under this SOW pertains to the development of the preferred scenarios that NREL engineers will develop technoeconomic models for. Discussions between NREL and EPA have led to agreement on the set of scenarios to be modeled as part of this project. This memo is a summarization of those scenari os per the deliverable under Task 1.

A total of 6 technoeconomic models will be developed as part of this effort. This is shown in Table 1. Three of the models use a biochemical platform to produce fuel ethanol from corn stover, and three of th e models use a thermochemical platform

- 1 -

# to produce Fischer-Tropsch fuels from w oody feedstocks. These models cover 3 specific timeframes: 2010, 2015, and 2022. Economics will be reported using year-$2007 estimated.

Each of these 6 models will assume a 2000 dry metric tonnes-per-day feedrate of biomass. The process configurations for the respective biochemical and thermochemical processes have been generally documented in two design reports. The primary difference is that the thermo chemical design report targets mixed alcohols production high ethanol concen tration instead of Fischer-Tropsch (FT) fuels.

Process Feedstock 2010 2015 2022 Biochemical Corn Stover Model 1 – Ethanol Model 2 – Ethanol Model 3 – Ethanol Thermochemical Wood Model 4 – FT Model 5 – FT Model 6 – FT Table 1 – Summary of Modeled Scenarios

Biochemical – http://www.nrel.gov/docs/fy02osti/32438.pdf 1 

# Thermochemical – http://www.nrel.gov/docs/fy07osti/41168.pdf 2



# The Biochemical Scenarios were listed as the highest priority. These will be completed first. The thermochemical models will entail a higher degree of modelingdevelopment since the mixed alcohol designs must be converted to FischerTropsch. The reasoning behind the decision to target FT fuels instead of mixed alcohols needs to be summarized if th is indeed becomes the final decision.

Standard economic assumptions in these models include:

♦ 10% IRR

♦ 100% equity financing

♦ 20-year plant life

♦ IRS MACRS depreciation accounting system (not straight-line)

♦ Depreciation period = 7 years gene ral plant, 20 years steam & utilities

♦ Income Tax Rate 39%

♦ Construction and startup period = 3.0 years

♦ N th 

# plant assumption – no extra costs included for first-of-a-kind pioneer plant “over-engineering”.

In addition to delivering the actual models to EPA, the following results will also be delivered for each model:

♦ Yield (gallon per dry ton)

♦ Minimum Ethanol Selling Price (MESP, $/gallon ethanol)

♦ Annual Production (MM gal/yr)

♦ Total Project Investment and Total Installed Cost ($MM)

♦ Assumed Feedstock Cost ($/dry ton) delivered

In order to quantify progress towards prog rammatic cost targets, analysts at NREL have developed what are kn own as State of Technology (SOT) assessments. These

- 2 -

# - 3 - could also be thought of as “experimentall y verified” cases since the data supplying these models is generated from actual bench- and pilot-scale experiments. In this fashion, the actual data is input into the technoeconomic models to assess what the plant economics might be if research resu lts were scaled to commercial scale. As the SOT costs reduce over time, progress ca n easily be quantified as can the level of challenge remaining. The 2007 Biochemical State of Technology Assessment was recently published as an NR EL report and can be found at http://www.nrel.gov/docs/fy08osti/43205.pdf 3 

# . The MESP was calculated to be $2.43/gallon (year 2007 estimated dollar). This model and data will serve as Model 1 under the biochemical 2010 scenario. Th is makes sense because of the assumed construction and startup period of 3 years. Similarly, NREL will also use its market target model, which contains process parameters and targets for 2012, to serve as the 2015 scenario models. The 2022 models will need to be developed.

The relationship of these SOT values are shown with respect to DOE Budget and Cost Targets in Figure 1 and 2. The cost target for year 2010 is consistent with the value proposed for the 2007 SOT 3 

# and the value for year 2015 is consistent with the Market Target case from the Aden, et. al. design report 1



# . Methodology and approach:

Process economics requires a wide range of detailed studies, including conceptual level of process design to develop proce ss flow diagram (based on research data from NREL and other data sources), rigorous materials and energy balance calculations (via commercial simulation t ools, Aspen Plus), Capital and project cost estimation (via in house model using spre adsheets), discounted cash flow economic model (via in house model using spreadsheets) and then a final calculation of minimum ethanol selling price.

Conceptual design refers to the engineering decisi on-making that is required to conceive a process from information on the products, feeds, and chemical and physical steps proposed as a basis (Douglas 1989 4 

# ). The effective use of conceptual design methods in the early stages of pr ocess design can have a large impact on overall process design and development. There are frequently many processes alternatives that can be chosen and many design variables to specify. Conceptual design approaches practically always include both assumptions and heuristics along with numerical modeling and optimization techniques. Overall process design basis has been determined based on years of NREL research. The process design presented here for model 2010, has refl ected the best available estimates for performance of an enzyme based process with the current status of our research efforts. Basis of the proc ess includes four steps:

I. Conversion of feedstocks to sugar. We have used corn stover as the feedstock exclusively in this study. Small variations to the process simulation and overall process conceptual level design are required if different feedstocks are introduced, such as switchgrass, miscant hus. The approach used to accomplish this step normally distinguishes different process technologies (or configurations) for the overall process de sign, since it is the most critical and challenging step.

# II. Fermentation sugar to ethanol. The fermenting organism Zymomonas mobilis is used in our research and is well studied organism for sugar fermentation. III. Ethanol recovery area. High purity of ethanol is produced with 99.5 wt% in the recovery area, using distillation columns, molecular sieve unit and water evaporation units. Although it is an energy intensive operation, the temperature gradient from the first dist illation column (or called beer column) can be used as a driving force for energy intensification in the area. Recycled water streams with reasonable levels of impurities are introduced into different areas such as pretreatment of feedst ocks, in order to optimize the water and/or steam usage. IV. Residue utilization. The solids from dist illation, the concentrated syrup from the evaporator, and the biogas from anae robic digestion are combusted in a fluidized bed combustor to produce high pressure steam for electricity production and provide process steam or heat. Excess electricity credits are collected in the cost analysis.

Overall design flow diagram is simplified in the following Figure:

Feedstock Handling

Corn Stover Steam & Acid 

## Pretreatment

Conditioning

Steam

Electricity 

## Burner/Boiler Turbogenerator Ethanol



## Distillation & Ethanol Purification Steam Lime

Gypsum CO 2 

## Enzyme



## Saccharification & Fermentation

Lignin Residue 

## Wastewater Treatment Dewatering

Recycle 

## Feedstock Handling

Corn Stover Steam & Acid 

## Pretreatment

Conditioning

Steam

Electricity 

## Burner/Boiler Turbogenerator Ethanol



## Distillation & Ethanol Purification Steam Lime

Gypsum CO 2 

## Enzyme



## Saccharification & Fermentation CO 2 

## Enzyme



## Saccharification & Fermentation

Lignin Residue 

## Wastewater Treatment Dewatering

Recycle

Lignin Residue 

## Wastewater Treatment Dewatering

Recycle



# Figure 1 – Schematic process flow diagram from corn stover to ethanol 1



# Brief Process Description: This design uses dilute acid pretreatment followed by enzymatic hydrolysis and co-fermentation with recombinant Zymomonas mobilis

. The corn stover (or biomass) is first treated with dilute sulfuric acid catalyst at a high temperature (190  ̊ C) for a short time (average at 2 minutes), liberating the hemicelluloses sugars and other compo unds. Before going into enzymatic hydrolysis, proper conditioning is required to detoxification to the enzyme and fermenting organisms. If overliming is used for conditioning, then a solid and liquid

- 4 -

# separation step would follow to remove gypsum from th e process. If ammonia is used, the neutralized salt remains in the li quor and would be forwarded to the next step without solid and liquid separation. Although the solid removal and liquid separation step for overlimed gypsum is beneficial to the overall capital cost, ammonia is much more expensive than lime; therefore, the overall cost in terms of MESP does not change much in either case . Detoxification is only applied to the liquor from pretreatment before charging into enzymatic hydrolysis. Solids from pretreatment will be interna lly washed before remixed with the de toxified liquor for simultaneous saccharification and fermenta tion. A purchased enzyme is added to the hydrolyzate at an optimized temperat ure for enzyme activity. In cases with higher temperature for saccharification than for fermentation, a cooling step is required to ensure growth of fermenting organism Zymomonas mobilis at anaerobic condition. Several days (total 3 to 7 days depending on the models or SOTs) are required to convert most of the cellulose and xylose to ethanol. The “beer” liquor with ~4-8wt% of ethanol is then sent to recovery unit to purify ethanol to the desired purity. The solids after fermentation are combusted in a fluidized bed combustor to produce high pr essure steam for electricity credits and process heat.

We chose to use the Aspen Plus simulation environment for our process simulator , which includes all the management and convergence of hundreds of steams and blocks. A detailed process diagram from conceptual design is provided.

Combined process flow diagram and rigoro us materials and energy data generated from Aspen Plus simulator are used to define detailed equipment sizes and costs using an in house sp readsheet model for capital cost . Please note that proper choices of equipment design and configurat ions are also critical, which internal processing technology researc h combined with outside engineering firm consulting were applied. Some purchased and installed costs for equipments are obtained from vendor quotes (and also inflated to 2007 dollar if the quote was obtained before year 2007). This exercise has been done for most of highly specialized units, such as fermentors. Other standard equipment unit costs are from the ICARUS cost estimation software. These units are norm ally pumps, heat exchangers, etc. The summary of the capital costs of each majo r operation area for all three models is listed in the following Table:

Capital Costs 2010 2015 2022
Pretreatment $23,000,000 $22,700,000 $19,000,000 Neutralization/Conditioning $8,400,000 $9,400,000 $7,600,000 Saccharification & Fermentation $20,500,000 $11,200,000 $10,100,000 Distillation and Solids Recovery $23,400,000 $26,100,000 $23,300,000 Wastewater Treatment $3,400,000 $3,700,000 $3,100,000 Storage $3,800,000 $2,400,000 $2,500,000 Boiler/Turbogenerator $45,500,000 $46,000,000 $43,200,000

Utilities $5,600,000 $5,500,000 $5,300,000 Total Installed Equipment Cost $133,500,000 $127,000,000 $114,000,000



# - 5 -

# Table 2 – Summary of capital cost for all three models

Operation cost (fixed and variable costs) is summarized in the following table for all three models:

($/yr) ($/gal Ethanol) ($/yr) ($/gal Ethanol) ($/yr) ($/gal Ethanol) Feedstock $46,400,000 0.84 $35,400,000 0.51 $35,400,000 0.50 CSL $7,700,000 0.14 $2,100,000 0.03 $1,700,000 0.02 Cellulase $17,900,000 0.32 $6,800,000 0.10 $5,400,000 0.08 Other Raw Matl. Costs $17,200,000 0.31 $3,700,000 0.05 $10,900,000 0.15 Waste Disposal $1,000,000 0.02 $2,700,000 0.04 $1,000,000 0.01 Electricity -$5,800,000 -0.10 -$6,500,000 -0.09 -$11,300,000 -0.16 Fixed Costs $8,900,000 0.16 $8,700,000 0.13 $8,200,000 0.12 Capital Depreciation $11,600,000 0.21 $11,000,000 0.16 $9,900,000 0.14 Average Income Tax $8,700,000 0.16 $8,300,000 0.12 $7,500,000 0.11 Average Return on Investment $21,300,000 0.38 $19,700,000 0.28 $17,800,000 0.25 Total $134,900,000 $2.43 $91,900,000 $1.33 $86,500,000 $1.21 2022 2010 2015 Operating Costs



# Table 3 – Summary of operating cost for all three models

Once the capital and operational costs ha ve been established, a discounted cash flow analysis can be used to determine the minimum selling price per gallon of ethanol produced . The discounted cash flow model calculates in iterations on the selling cost of ethanol until the net value of the overall design project is approaching zero. In Table 3, the minimum selling price per gallon of ethanol was calculated for each model studied in this report.

General comparison among all three models:

The 2015 scenario adapts the market target model used in 2002 design report, in which an overliming step was used to condition the pretreated biomass prior to enzymatic hydrolysis. Lime is added at greater than stoichiometric amounts to both neutralize the sulfuric acid present, as well as to further detoxify the material through mechanisms that are not fully und erstood. The benefit is that lime is cheap in comparison against other potential conditioning agents. Overliming conditioning has a potential of high sugar degradation resulting in yield loss. Overliming also has mixing challenges due to the insoluble nature of the lime. Gypsum precipitates out of solution. Th is can be a potentially large solid waste emission point. Since that time, NREL has researched alternate conditioning technologies, particularly ammonium hydroxide. While ammonium hydroxide as a conditioning agent is more expensive than lime, it is able to be used on the entire slurry. Not only it does not have mixing issue, but also the solid liquid separation unit can be removed because a mmonium salts are soluble. The main benefit is that it greatly minimizes the sugar degradat ion losses seen in overliming, and has potential nutritive benefits downstream in fermentation. However, the fate of the ammoniated species downstream in the proc ess has not been thoroughly explored. The potential for increased NOx, SOx emission s in the flue gas or for higher loading to wastewater treatment are both possib ilities. The 2010 and 2022 scenarios both assume ammonium hydroxide conditioning, while the 2015 scenario assumes overliming conditioning. As a result of this variation, NREL data shows that the "other raw materials" category drops from 31.1 cents-per-gallon in 2010 to 5.4 cents in 2015 and rises back to 16.2 cents in 2022. Much of this is due to the

- 6 -

# difference in costs between lime and ammonia assumed in the models. Also, note that the waste disposal costs rise from 1.9 cents per gallon to 4 cents and drops back down to 1.5 cents. Again, much of this is due to the increased cost of gypsum disposal in the 2012 scenario where overliming is used.

Detailed discussion:

1. Model 2010 This model uses 2007 State of Technology SOT assumptions, assuming three years of construction and start-up in 2007.

Figure 2 - “ Back Cast” State of Technology Cases 2007 3



# - 7 -

### 2005 Post Enz y me Subcontract 2007 2008 2009 2010 2011 2012 Market Target

Minimum Ethanol Selling Price $2.52 $2.43 $1.33
TPI/Annual Gallon $4.79 $4.17 $3.17
Yield (Gallon/dry ton) 65 72 90

Feedstock
Feedstock Cost ($/dry ton) $60 $60 $60 $46

Pretreatment
Solids Loading (wt%) 30% 30% 30% 30% 30% 30% 30%
Xylan to Xylose 63% 75% 75% 75% 85% 90% 90%
Xylan to Degradation Products 0% 13% 8% 6% 6% 6% 0%
Conditioning
Xylose Sugar Loss 13% 2% 2% 2% 2% 1% 1%
Glucose Sugar Loss 12% 1% 1% 1% 1% 1% 0%
Enzymes Enzyme Contribution ($/gal EtOH) $0.32 $0.32 $0.32 $0.32 $0.16 $0.10 $0.10

Saccharification & Fermentation
Total Solids Loading (wt%) 20% 20% 20% 20% 20% 20% 20% Combined Saccharification & Fermentation Time (d) 7 77753 3

Overall Cellulose to Ethanol 0% 85% 85% 85% 85% 85% 85%
Xylose to Ethanol 76% 76% 80% 80% 80% 85% 85% Minor Sugars to Ethanol 0% 0% 40% 40% 80% 85% 85% 

# Table 4 - State of Technology Cases 2007 Summary 3



# 2. Model 2015

This model uses 2012 market goal of “Cost effective cellulosic ethanol, $1.33/gal, as primary market goal of DOE programs, shown in Figure 1 and Table 2. Similar to 2010 model, it is assumed three years of construction and start-up in 2012. Main cost reduction is from feedstock, enzyme pricing, as well as improvements on xylan, sugar yields.

3. Model 2022

Research beyond 2012 could be focused on the following area: Feedstocks, pretreatment processing technologies, advanced enzyme systems, advanced fuels, and advanced process system. For feedstoc k, more sustainable crops beyond corn stover (switchgrass, miscanthus, and many more) are needed, since there is a potential of cost increase due to incr easing demand and larger distances for transportation. Research on transgen ic crops could also provide further improvement in the area of feedstocks. In pretreatment, a lower cost in processing, less severe operational conditions are needed. This could be coupled with advanced enzymes, so combined yield in pretreatment, saccharification and fermentation

- 8 -

# could be improved drastically. For advanc ed enzyme systems, research should be focused on advanced cellulase, hemice llulase and accessory enzymes. Other advanced fuels, such as butanol, hydroc arbon fuels, advanced ethanologens, can release the burden of the overall biofuel dependence solely on cellulosic ethanol. This would provide alternatives for future research. Higher solid loading to all the major reaction steps is always an exci ting but challenging topic for process improvement in this biological conversion process for cellulosic ethanol. Additionally, the biochemical conversion process can be integrated with thermochemical conversion process using process intensif ication techniques, or using combined bioprocessing techniques. Therefore, with all the above ongoing research topics, we can assume the base design model of 2022 can be a dramatic process improvement on a variety of changes, such as enzyme cost, ethanol yield, sugar loss, minor sugar yield, etc.

A summary of the base condition studied in model 2010, model 2015 and model 2022 (assuming three years of construction and start-up in 2019 as well) are shown in Appendix A.

4. Process concept comparison:

Comparison of the previously reported SO T values (2010 model) and market goal values (2015 model) can be sensitive because underlying assumptions may be updated and improved from year to year. For example:

• Total yield of ethanol per dry ton of biomass Theoretical yield of ethanol is 112.7 gal/ton dry basis of corn stover. The yield (and ethanol production) calculated based on the overall conversion is gradually increased over the years with R&D effects, as shown in the following table: MODEL YEAR 2010 2015 2022 Ethanol Production (MM Gal. / Year) 55.5 69.3 71.3 Ethanol Yield (Gal / Dry US Ton Feedstock) 71.9 89.8 92.3 

# Table 5 – Comparison of ethanol yield and production

• Feedstock price The price of feedstock in FY 2005 SOT model was $53 per dry ton to the plant gate and was $60 per dry ton in FY 2007 SOT of overall delivered cost. The $46 per dry ton was based on President’s AEI goal in 2007 dollar. In this study, 2015 and 2022 models used $46 per dry ton, while 2010 model used $60 per dry ton feedstock delivered. MODEL YEAR 2010 2015 2022 Feedstock price ($/dry ton) 60 46 46 

# Table 6 – Comparison of feedstock pricing

• The yield in pretreatment has been assu med to increase gradually over years of research efforts worldwide. The summary of yields of all three models are listed as following including all the basis operating conditions in the pretreatment area:

- 9 -

## Pretreatment 2010 2015 2022 Acid Conc (wt%) 1.64% 1.64% 1.64% Acid Loading (g acid/g dry biomass) 0.038 0.038 0.024 Total Solids (wt%) 29.8% 30.0% 40.0% Temperature (°C) 190 190 190 Pressure (atm) 12 12 12 Conversions: Cellulose to Glucose 0.099 0.09 0.099 Xylan to Xylose 0.75 0.9 0.9 Xylan to Furfural 0.048 0.05 0.048 Minor surgar to monomer 0.75 0.9 0.9 

# Table 7 – Comparison of pretreatme nt operational conditions

• The contamination ratio 

# MODEL YEAR 2010 2015 2022 Contamination 7% 3% 1% 

# Table 8 – Comparison of contamination rate

• The sugar loss due to severity of pretreatment condition In addition to contamination loss, sugar loss due to severity of pretreatment condition cannot be neglected. Conditioning 2010 2015 2022 Ca(OH)2 to Gypsum 5634 0 0 Sugar Conversion to TAR: Xylose 0.018 0.018 0 Glucose 0.006 0.006 0 Minor Sugars 0.006 0.006 0 

# Table 9 – Comparison of conditionings

• Enzyme cost The cost of enzyme was used to be equivalent to 32, 10 and 8 cents per gallon ethanol produced, in model 2010, 2015 and 2022 respectively; assuming cutting edge technologies would be matured by then without any availability issues. MODEL YEAR 2010 2015 2022 Enzyme cost ($/gal Ethanol) 0.32 0.10 0.08 

# Table 10 – Comparison of enzyme costs

• Saccharification conditions In addition to small changes in reaction conversion, the total solids have assumed to change dramatically to the out year model in 2022 to improve process intensification as well as to improve capital investment. Consequently, the total solids are different in model 2022 from models 2010 and 2015 in fermentation.

- 10 -

## Saccharification 2010 2015 2022 Enzyme Loading (mg/g cell) 5.5 20.0 20.0 Total Solids (wt%) 20.0% 20.0% 25.0% Insoluble Solids (wt%) 11.4% 11.1% 13.2% Temperature (°C) 32 65 35 Pressure (atm) 1 1 1 Residence Time ( da y s ) 5 1.5 Conversions: Cellulose to Glucolig 0.024 0.04 0.024 Cellulose to Cellobiose 0 0.012 0 Cellulose to Glucose 0.9 0.9 0.9 1.5



# Table 11 – Comparison of Saccharification conditions

• Fermentation conditions With higher solids level and improved yield in fermentation, the final ethanol concentration in the liquor out of the fe rmentors increased significantly. This results in improved energy efficien cy in ethanol purification step.
Fermentation 2010 2015 2022 Total Solids (wt%) 0.20 0.20 0.25 Insoluble Solids (wt%) 0.06 0.05 0.06 Temperature (°C) 32 32 32 Pressure (atm) 1 1 1 Residence Time (days) 2 1.5 1.5 Conversions: Glucose to Ethanol 0.95 0.95 0.95 Glucose to Zymo 0.02 0.02 0.02 Glucose to Glycerol 0.004 0.004 0.004 Glucose to Succinic Acid 0.006 0.006 0.006 Glucose to Acetic Acid 0.015 0.015 0.015 Glucose to Lactic Acid 0.002 0.002 0.002 Xylose to Ethanol 0.756 0.85 0.886 Xylose to Zymo 0.019 0.019 0.019 Xylose to Glycerol 0.003 0.003 0.003 Xylose to Xylitol 0.046 0.046 0.046 Xylose to Succinic Acid 0.009 0.009 0.009 Xylose to Acetic Acid 0.014 0.014 0.014 Xylose to Lactic Acid 0.002 0.002 0.002 Minor Sugar to Ethanol 0 0.85 0.9 Minor Sugar to Zymo 0 0.019 0.019 Minor Sugar to Glycerol 0 0.003 0.003 Minor Sugar to Succinic Acid 0 0.015 0.015 Minor Sugar to Acetic Acid 0 0.014 0.014 Arabinose to Lactic Acid 0 0.002 0.002 Contamination Loss 7% 3% 1% Ethanol Out of Fermenters (wt%) 4.88% 6.21% 8.13% 

# Table 12 – Comparison of fermentation conditions

• Emission data

- 11 -Boiler ash Fermentation off gas Flue gas Gypsum waste Boiler ash Fermentation off gas Flue gas Boiler ash Fermentation off gas Flue gas Mass Flow kg/hr Biomass 205.0

- 89.2 266.1 177.2

- 81.2 171.1

- 89.2 aldehydes

- 0.0 2.1 3.4

- 0.0 1.3

- 0.0 2.1 Organic acid

- 0.0 44.7 23.1

- 0.0 43.2

- 0.0 17.7 Nutrients

- 0.0 4,660.0 1.1

- 0.0 1,406.5

- 0.0 1,146.4 Sugars

- - 77.6 135.8

- - 33.3

- - 30.6 ASH 4,308.9

- - 21.697 4,287.4

- - 4,308.9

- - H2O

- 338.9 124,850.3 1261.205

- 432.3 68,749.3

- 433.0 74,660.5 N2

- 0.3 265,393.6 0

- 0.3 206,378.0

- 0.3 220,115.0 CO2

- 18,750.7 80,723.3 0

- 23,381.3 65,694.7

- 24,017.8 65,204.0 O2

- 153.2 13,079.1 0

- 196.4 10,277.8

- 196.9 10,539.8 CH4

- - 2.4 0

- - 2.8 - - 2.1 NO

- - - 0

- - - - - - NO2

- - 74.8 0

- - 60.9

- - 59.4 SO2

- 0.0 9,424.0 0

- 0.0 100.3

- - 2,812.9 CO

- - 74.8 0

- - 60.9

- - 59.4 Others

- 0.0 0.3 2.755

- 0.0 0.1 - 0.0 0.2 H2SO4

- 4.3 0.1 0.217

- 4.3 0.0 - 4.3 0.1 ETHANOL

- - 0.6 12.027

- - 0.6 - - 0.6 Emission Data 2010 2015 2022



# Table 13 – Comparison of emission data

• Overall condition comparison

2007 2012 Market Target 2019 Outyear Target Minimum Ethanol Sellin g Price $2.43 $1.33 $1.21 TPI/Annual Gallon $4.17 $3.17 $2.79 Yield (Gallon/dry ton) 72 90 92 Feedstock Feedstock Cost ($/dry ton) $60 $46 $46 Pretreatment Solids Loadin g (wt%) 30% 30% 40% Xylan to Xylose 75% 90% 90% Xylan to De g radation Products 13% 5% 5% Conditionin g Xylose Su g ar Loss 2% 1% 0% Glucose Su g ar Loss 1% 0% 0% Enzymes Enzyme Contribution ($/ g al EtOH) $0.32 $0.10 $0.08 Saccharification & Fermentation Total Solids Loadin g (wt%) 20% 20% 25% Combined Saccharification & 7 3 3 Overall Cellulose to Ethanol 85% 85% 85% Xylose to Ethanol 76% 85% 90% Minor S u g ars to Et h ano l 0% 8 5 % 90 % 

# Table 14 – Comparison of overall conditions

• Process economics overview
Units 2010-BC 2015-BC 2022-BC Minimum Ethanol Selling Price ($/gallon) ($/gallon) $2.43 $1.33 $1.21 Annual Production (MM gal/yr) (MM gallon/yr) 55.5 69.3 71.3 Yield (gallon ethanol / ton biomass) (gallon ethanol / dry ton biomass) 71.9 89.8 92.3 Total Installed Cost ($MM) $133.5 $127.0 $124.5 Total Project Investment ($MM) $231.7 $220.1 $202.9 Feedstock Cost ($ / dry ton) $60.10 $45.90 $45.90

Reference Model: A 0802A, T0808D A 0806H, T0808E T0809C 

# Table 16 – Comparison of overall process economics

- 12 -

# An analysis was performed to “back cast” current knowledge to the previous years’ State of Technology cases so that the ec onomic effects of improved technology demonstrations can more easily identified . The following are important features of the back-casting exercise:

• All costs were put on a 2007 year estimated basis.

• The feedstock composition used was that reported in the 2007 SOT 3



# . Feedstock costs were $60 per dry ton corn stover for model 2010 referenced to 2007 SOT, and they were maintained at $46 per dry ton corn stover for years in 2012 and beyond. More data would be available soon from feedstock design report by Idaho National Laboratory.

• Cellulase costs were chosen to make cost equivalent to $0.32 to $0.08 per gal of ethanol depending on the model year.

• Sugar losses from overliming was applied only to 2010 model and ammonia conditioning for models of 2015 and 2022, which leads to less sugar loss.

• The solid separation step to remove gypsum is then removed for model 2015 and 2022, resulting in slight reduction in equipment cost in pretreatment area. However, the ammoni a is considerably more expensive than lime.

5. Sensitivity study on the main effects for model 2022:

Beyond year 2012, although the research targets are stated clearly, the uncertainty remains. It makes sense to research on how sensitive each main parameter on the final cost structure, therefore a sensit ivity study using design of experiment statistical analysis is used.

Seven main effects are selected for this study: I. Feedstock cost, from $45.9 to $60.1 per dry ton corn stover. II. Enzyme cost, adjusted to be equiva lent to 5-10 cents per gal ethanol produced. III. Contamination ratio from 1 to 3%. IV. Sugar loss due to pretreatment condition from 25% to 50% of the values in 2007 SOT. V. Xylan yield to xylose, mannan yield to mannose, galactan yield to galactose, arabinan yield to arabinose, from 80% to 90%. VI. Xylose yield to ethanol, from 80% to 90%. VII. Minor sugar yield to ethanol, from 80% to 90%.

Feedstock p rice $/ton Enzyme cost c/gal

ETOH contamination % Sugar loss % of 2007SOT data Xylan to Xylose y ield % Xylose to ethanol y ield % Minor sugar y ield % - 45.9 5 1 25 80 80 80 + 60.1 10 3 50 90 90 90 

# Table 17 – Parameters (or Main effects) for full factorial design of experiments

- 13 -

# The total sensitivity cases are 128 (2 7 

# ) if each main effect is two-fold under full factorial design of experiment. Detailed stat istical analysis refers to the Appendix A. The conclusions are listed as following:

For MESP ($/gal ethanol):

• All seven parameters are statistically si gnificant main effects, and feedstock price is the strongest main effect among all in the studied data range.

Figure 3 – Pareto chart for MESP $/gal

• A number of binary effects are also statistically significant. An interaction plot shows the impact that changing the se ttlings of one factor has on another factor. Because an interaction can magnify or diminish main effects, evaluating interactions is extremely impo rtant. Whether an interaction effect is statistically important can also be judged by the P value in the Design of Experiment analysis (shown in Appendix B, interaction plot). For instance, there is no interaction effect between feedstock and enzyme costs, as shown in P value of 0.944, or shown in the inte raction plot as almost perfect parallel lines of both. AB CE BD BF BG BC BE AD DG EF DE CD FG CG DF CF EG AG AC AF D AE G C F B E A



### 1600 1400 1200 1000 800 600 400 200 0Term



### Standardized Effect 2

A F eedstock price $ /ton B Enzy me cost c/gal ETO H C contamination % D Sugar loss % SO T E Xy lan to Xy lose y ield % F Xy lose to ethanol y ield % G Minor sugar y ield % Factor Name 

## Pareto Chart of the Standardized Effects (response is ETOH cost $/gal, Alpha = 0.05)



## Effect on MESP: A >>E>B>F>C>G>D



# - 14 -60.1 45.9 152

144

136
10 5 3 1

50 25 152

144

136

90 80 90 80

90 80 152

144

136 Feedstock price $/tonMean Enzy me cost c/gal ETO H contamination %

Sugar loss %SO T Xy lan to Xylose y ield % Xy lose to ethanol yield %

Minor sugar y ield % 

## Main Effects Plot for ETOH cost $/gal Data Means



# Figure 4 – Main effect chart for MESP $/gal. Leverage of individual main effect can be studied using this chart.

• Please note that although main e ffects of contamination%, sugar loss percentage of values in 2007 SOT, and minor sugar yield% are relatively less significant to MESP ($/gal ethanol), it is due to the studied data range of these parameters is quite narrow. The st atistical properties of all the main effect parameters are depe ndent strongly on the data range studied. In another word, if minor sugar yields are from 0 to 90%, it could be more statistically important than what is in this study.

For percentage actual ethanol yield to theoretical yield:

Feedstock and enzyme costs are not impactin g the ethanol yield at all. Therefore, there are five parameters as main effects, as following:

I. Contamination ratio from 1 to 3%. II. Sugar loss due to pretreatment condition from 25% to 50% of the values in 2007 SOT. III. Xylan yield to xylose, mannan yield to mannose, galactan yield to galactose, arabinan yield to arabinose, from 80% to 90%. IV. Xylose yield to ethanol, from 80% to 90%.

V. Minor sugar yield to ethanol, from 80% to 90%.

The conclusions are listed as following:

• All seven parameters are statistically si gnificant main effects, and feedstock price is the strongest main effect among all in the studied data range.

- 15 -CG DF CD DG FG CF DE CE EG EF D G C F E



### 500 400 300 200 100 0Term



### Standardized Effect 2.0

C contamination % D Sugar loss %SO T E Xylan to Xylose y ield % F Xylose to ethanol y ield % G Minor sugar y ield % Factor Name 

## Pareto Chart of the Standardized Effects response is Current Yield (Actual/Theoretical), Alpha = 0.05



# Figure 5 – Pareto chart for ethanol yield

3 1 0.79

0.78

0.77

0.76

50 25 90 80

90 80 0.79

0.78

0.77

0.76

90 80 contamination %Mean Sugar loss %SOT Xylan to Xylose yield %

Xylose to ethanol yield % Minor sugar yield % 

## Main Effects Plot for Current Yield (Actual/Theoretical) Data Means



# Figure 6 – Main effect chart for ethanol yield

• A number of binary effects are also statis tically significant. Binary effect chart is attached in Appendix B for reference.

Please note that although main effects of contamination%, sugar loss percentage of values in 2007 SOT, and minor sugar yield% are relatively insignificant to MESP ($/gal ethanol), it is due to the truly narrowed studied data range of these parameters. The statistical prop erty of the each main effect is strongly influenced by the data range studied.

- 16 -

# - 17 - Conclusion:

Three biochemical conversion models, model 2010, model 2015 and model 2022, from corn stover to ethanol were studied in this report. Each model has been studied from conceptual level of design, rigorous calculations of mass and energy balances using Aspen Plus simulation tools, detailed and logical capital cost to the final calculation of minimum selling price per gallon ethanol. Using a discounted cash flow rate of return analysis, the minimum ethanol selling prices (MESP) are $2.43, $1.33 and $1.21 per gal ethanol with respect to model 2010, 2015 and 2022. Detailed comparison of process condition, operational condition and cost structures are discussed in the report. Part icularly in model 2022, since there are too many known main effects on the final minimum selling price per gallon ethanol, a sensitivity study using full factorial Design of Experiments is applied to understand which main effect has the most significan t impact, as well as to understand any existing binary effects. This sensitivity study result can help to lead future study. For instance, it is logical that feedstock price is the dominant main effect on minimum selling price per gallon ethanol, while the xylan yield is the dominant for overall ethanol yield in the cellulosic proce ss. Binary effects based on this sensitivity study of data range are also statistically significant to both minimum selling price per gallon ethanol and overall ethanol yield.

A similar study will be done for all three th ermochemical conversion models 4, 5 and 6 in Table 1.

References:

1. Aden, A.; Ruth, M.; Ibsen, K.; Jechura, J.; Neeves, K.; Sheehan, J.; Wallace, R. Lignocellulosic Biomass to Ethanol Proc ess Design and Economics Utilizing CoCurrent Dilute Acid Prehydrolysis and Enzy matic Hydrolysis For Corn Stover. NREL Report NREL/TP-510-32438, June 2002. http://www.nrel.gov/docs/fy02osti/32438.pdf 2. Phillips, S.; Aden, A.; Jechura, J; Da yton, D. (2007). “Thermochemical Ethanol via Indirect Gasification and Mixed Alcoho l Synthesis of Lignocellulosic Biomass.” National Renewable Energy Laboratory, Golden, CO. NREL Report No. TP-510- 41168. Http://www.nrel.gov/docs/fy07osti/41168.pdf 3. Aden, A. “FY07 State of Technology Update” (2007), http://devafdc.nrel. gov/bcfcdo c/10025.pdf 4. Douglas, J. M., Conceptual Design of ChemicalProcesses, McGraw-Hill (1989

# Appendix A

Pretreatment Saccharification Fermentation Acid Conc ( wt% ) 0.0164 Enz y me Loadin g ( m g / g cell ) 5.5 T otal Solids ( wt% ) 20.1% Acid Loadin g (g acid/ g dr y biomass ) 0.0381 T otal Solids ( wt% ) 20.0% Insoluble Solids ( wt% ) 5.6% Total Solids ( wt% ) 0.2976 Insoluble Solids ( wt% ) 11.4% T em p erature ( °C ) 32 Tem p erature ( °C ) 190 T em p erature ( °C ) 32 Pressure ( atm ) 1.0 Pressure ( atm ) 12.1 Pressure ( atm ) 1.0 Residence Time ( da y s ) 2 Residence Time ( min. ) Residence Time ( da y s ) 5 Conversions: Conversions: Conversions: Glucose to Ethanol 0.95 Cellulose to Glucoli g 0.003 Cellulose to Glucoli g 0.024 Glucose to Z y mo 0.02 Cellulose to Cellobiose 0 Cellulose to Cellobiose 0 Glucose to Gl y cerol 0.004 Cellulose to Glucose 0.099 Cellulose to Glucose 0.9 Glucose to Succinic Acid 0.006 Cellulose to HMF 0.003 Glucoli g to Cellobiose 0 Glucose to Acetic Acid 0.015 X y lan to Oli g omer 0.06 Glucoli g to Glucose 0 Glucose to Lactic Acid 0.002 X y lan to X y lose 0.75 Cellobiose to Glucose 1 X y lose to Ethanol 0.756 X y lan to Furfural 0.048 X y lan to Oli g omer 0 X y lose to Z y mo 0.019 X y lan to Ta r 0.085 X y lan to X y lose 0 X y lose to Gl y cerol 0.003 Mannan to Oli g omer 0.06 X y lose Oli g omer to X y lose 0 X y lose to X y litol 0.046 Mannan to Mannose 0.75 X y lan to Ta r 0 X y lose to Succinic Acid 0.009 Mannan to HMF 0.048 Arabinan to Oli g omer 0 X y lose to Acetic Acid 0.014 Galactan to Oli g ome r 0.06 Arabinan to Arabinose 0 X y lose to Lactic Acid 0.002 Galactan to Galactose 0.75 Galactan to Oli g ome r 0 Arabinose to Ethanol 0 Galactan to HMF 0.048 Galactan to Galactose 0 Arabinose to Z y mo 0 Arabinan to Oli g omer 0.06 Galactose Oli g omer to Galactose 0 Arabinose to Gl y cerol 0 Arabinan to Arabinose 0.75 Mannan to Oli g omer 0 Arabinose to Succinic Acid 0 Arabinan to Furfural 0.048 Mannan to Mannose 0 Arabinose to Acetic Acid 0 Arabinan to Ta r 0.085 Mannose Oli g omer to Mannose 0 Arabinose to Lactic Acid 0 Acetate to Oli g ome r 0 Galactose to Ethanol 0 Acetate to Acetic Acid 1 Galactose to Z y mo 0 Furfural to Ta r 1 Su g ar & Solids Flow Rates ( k g /hr ) Galactose to Gl y cerol 0 HMF to Tar 1 Soluble Su g ars From PT 26,248 Galactose to Succinic Acid 0 Li g nin to Soluble Li g nin 0.1 Other Soluble Solids From PT 11,446 Galactose to Acetic Acid 0 Soluble Su g ars in Purchased Cellulase 0 Galactose to Lactic Acid 0 Other Sol Solids in Purchased Cellulase 0 Mannose to Ethanol 0 S/L Se p aration Soluble Su g ars in Produced Cellulase 0 Mannose to Z y mo 0 Water/Hydrolyzate Ratio (kg/kg) 0.58 Other Sol Solids in Produced Cellulase 0 Mannose to Gl y cerol 0 Water to S/L Separator (kg/hr) 136,268 Mannose to Succinic Acid 0 Dilution Water (kg/hr) 43,391 Soluble Su g ars From Sacc 49,357 Mannose to Acetic Acid 0 Other Soluble Solids From Sacc 10,301 Mannose to Lactic Acid 0 Soluble Su g ars From Seed Train 1,068 Other Soluble Solids From Seed Train 1,251 Contamination Loss 7.0% Conditionin g Soluble Su g ars From DAP 0 Ca ( OH ) 2 to G yp sum #N/A Other Soluble Solids From DAP 0 Ethanol Out of Fermenters (wt%) 4.9% Su g ar Conversion to TAR: Soluble Su g ars From CSL 0 X y lose 0.018 Other Soluble Solids From CSL 2,215 Arabinose 0.018 Glucose 0.006 Galactose 0.006 Mannose 0.006 Cellobiose 0.006



# Table A1 - Operation Condition in Model 2010 Reference : Aspen Model A0802APretreatment Saccharification Fermentation Acid Conc ( wt% ) 0.0164 Enz y me Loadin g ( m g / g cell ) 20.0 T otal Solids ( wt% ) 19.7% Acid Loadin g (g acid/ g dr y biomass ) 0.0377 T otal Solids ( wt% ) 20.0% Insoluble Solids ( wt% ) 5.1% Total Solids ( wt% ) 0.2996 Insoluble Solids ( wt% ) 11.1% T em p erature ( °C ) 32 Tem p erature ( °C ) 190 T em p erature ( °C ) 65 Pressure ( atm ) 1.0 Pressure ( atm ) 12.0 Pressure ( atm ) 1.0 Residence Time ( da y s ) 1.5 Residence Time ( min. ) Residence Time ( da y s ) 1.5 Conversions: Conversions: Conversions: Glucose to Ethanol 0.95 Cellulose to Glucoli g 0.007 Cellulose to Glucoli g 0.04 Glucose to Z y mo 0.02 Cellulose to Cellobiose 0.007 Cellulose to Cellobiose 0.012 Glucose to Gl y cerol 0.004 Cellulose to Glucose 0.09 Cellulose to Glucose 0.9 Glucose to Succinic Acid 0.006 Cellulose to HMF 0 Glucoli g to Cellobiose 0 Glucose to Acetic Acid 0.015 X y lan to Oli g omer 0.025 Glucoli g to Glucose 0 Glucose to Lactic Acid 0.002 X y lan to X y lose 0.9 Cellobiose to Glucose 1 X y lose to Ethanol 0.85 X y lan to Furfural 0.05 X y lan to Oli g omer 0 X y lose to Z y mo 0.019 X y lan to Ta r 0 X y lan to X y lose 0 X y lose to Gl y cerol 0.003 Mannan to Oli g omer 0.025 X y lose Oli g omer to X y lose 0 X y lose to X y litol 0.046 Mannan to Mannose 0.9 X y lan to Ta r 0 X y lose to Succinic Acid 0.009 Mannan to HMF 0.05 Arabinan to Oli g omer 0 X y lose to Acetic Acid 0.014 Galactan to Oli g ome r 0.025 Arabinan to Arabinose 0 X y lose to Lactic Acid 0.002 Galactan to Galactose 0.9 Galactan to Oli g ome r 0 Arabinose to Ethanol 0.85 Galactan to HMF 0.05 Galactan to Galactose 0 Arabinose to Z y mo 0.019 Arabinan to Oli g omer 0.025 Galactose Oli g omer to Galactose 0 Arabinose to Gl y cerol 0.003 Arabinan to Arabinose 0.9 Mannan to Oli g omer 0 Arabinose to Succinic Acid 0.015 Arabinan to Furfural 0.05 Mannan to Mannose 0 Arabinose to Acetic Acid 0.014 Arabinan to Ta r 0 Mannose Oli g omer to Mannose 0 Arabinose to Lactic Acid 0.002 Acetate to Oli g ome r 0 Galactose to Ethanol 0.85 Acetate to Acetic Acid 1 Galactose to Z y mo 0.019 Furfural to Ta r 1 Su g ar & Solids Flow Rates ( k g /hr ) Galactose to Gl y cerol 0.003 HMF to Tar 1 Soluble Su g ars From PT 28,093 Galactose to Succinic Acid 0.015 Li g nin to Soluble Li g nin 0.05 Other Soluble Solids From PT 10,529 Galactose to Acetic Acid 0.014 Soluble Su g ars in Purchased Cellulase 0 Galactose to Lactic Acid 0.002 Other Sol Solids in Purchased Cellulase 0 Mannose to Ethanol 0.85 S/L Se p aration Soluble Su g ars in Produced Cellulase 0 Mannose to Z y mo 0.019 Water/Hydrolyzate Ratio (kg/kg) 0.58 Other Sol Solids in Produced Cellulase 0 Mannose to Gl y cerol 0.003 Water to S/L Separator (kg/hr) 135,470 Mannose to Succinic Acid 0.015 Dilution Water (kg/hr) 58,060 Soluble Su g ars From Sacc 51,778 Mannose to Acetic Acid 0.014 Other Soluble Solids From Sacc 9,476 Mannose to Lactic Acid 0.002 Soluble Su g ars From Seed Train 612 Other Soluble Solids From Seed Train 1,158 Contamination Loss 3.0% Conditionin g Soluble Su g ars From DAP 0 Ca ( OH ) 2 to G yp sum 0.000 Other Soluble Solids From DAP 0 Ethanol Out of Fermenters (wt%) 6.2% Su g ar Conversion to TAR: Soluble Su g ars From CSL 0 X y lose 0.018 Other Soluble Solids From CSL 545 Arabinose 0.018 Glucose 0.006 Galactose 0.006 Mannose 0.006 Cellobiose 0.006



# Table A 2 - Operation Condition in Model 2015 Reference : Aspen Model T0808E

# Table A3 - Operation Condition in Model 2022 Reference : Aspen Model T0809C

# Appendix B

Minitab Project Report

82.0% 81.0% 80.0% 79.0% 78.0% 77.0% 76.0% 75.0% 74.0% 73.0% 165

160

155

150

145

140

135

130

125

Current Yield (Actual/TheoreticETOH cost $/gal 

# Scatterplot of ETOH cost $/gal vs Current Yield (Actual/Theoretic

Factorial Fit: ETOH cost $/ versus Feedstock pr, Enzyme cost , ...

Estimated Effects and Coefficients for ETOH cost $/gal (coded units)

Term Effect Coef SE Coef T P Constant 144.119 0.005699 25289.68 0.000 Feedstock price $/ton 16.515 8.257 0.005699 1448.97 0.000 Enzyme cost c/gal ETOH 5.067 2.534 0.005699 444.60 0.000 contamination % 2.431 1.216 0.005699 213.33 0.000 Sugar loss %SOT 0.260 0.130 0.005699 22.78 0.000 Xylan to Xylose yield % -6.217 -3.108 0.005699 -545.46 0.000 Xylose to ethanol yield % -3.439 -1.719 0.005699 -301.71 0.000 Minor sugar yield % -1.071 -0.536 0.005699 -94.01 0.000 Feedstock price $/ton* 0.001 0.001 0.005699 0.11 0.914 Enzyme cost c/gal ETOH Feedstock price $/ton* 0.154 0.077 0.005699 13.51 0.000 contamination % Feedstock price $/ton* 0.017 0.008 0.005699 1.49 0.139 Sugar loss %SOT Feedstock price $/ton* -0.386 -0.193 0.005699 -33.91 0.000 Xylan to Xylose yield % Feedstock price $/ton* -0.220 -0.110 0.005699 -19.32 0.000 Xylose to ethanol yield %

## Feedstock price $/ton* -0.069 -0.035 0.005699 -6.06 0.000 Minor sugar yield % Enzyme cost c/gal ETOH* 0.005 0.003 0.005699 0.47 0.642 contamination % Enzyme cost c/gal ETOH* 0.002 0.001 0.005699 0.16 0.874 Sugar loss %SOT Enzyme cost c/gal ETOH* -0.008 -0.004 0.005699 -0.66 0.509 Xylan to Xylose yield % Enzyme cost c/gal ETOH* -0.002 -0.001 0.005699 -0.19 0.852 Xylose to ethanol yield % Enzyme cost c/gal ETOH* 0.003 0.001 0.005699 0.26 0.798 Minor sugar yield % contamination %*Sugar loss %SOT 0.035 0.017 0.005699 3.04 0.003 contamination %* 0.002 0.001 0.005699 0.15 0.880 Xylan to Xylose yield % contamination %* 0.042 0.021 0.005699 3.68 0.000 Xylose to ethanol yield % contamination %*Minor sugar yield % -0.036 -0.018 0.005699 -3.13 0.002 Sugar loss %SOT* 0.033 0.016 0.005699 2.86 0.005 Xylan to Xylose yield % Sugar loss %SOT* 0.036 0.018 0.005699 3.20 0.002 Xylose to ethanol yield % Sugar loss %SOT*Minor sugar yield % -0.022 -0.011 0.005699 -1.97 0.052 Xylan to Xylose yield %* -0.030 -0.015 0.005699 -2.66 0.009 Xylose to ethanol yield % Xylan to Xylose yield %* -0.062 -0.031 0.005699 -5.48 0.000 Minor sugar yield % Xylose to ethanol yield %* -0.035 -0.018 0.005699 -3.08 0.003 Minor sugar yield %

S = 0.0644737 PRESS = 0.687939 **R-Sq = 100.00% R-Sq(pred) = 99.99% R-Sq(adj) = 100.00%**

Analysis of Variance for ETOH cost $/gal (coded units)

Source DF Seq SS Adj SS Adj MS F P Main Effects 7 11392.2 11392.2 1627.46 391513.15 0.000 2-Way Interactions 21 7.7 7.7 0.37 87.93 0.000 Residual Error 99 0.4 0.4 0.00 Total 127 11400.3

Estimated Coefficients for ETOH cost $/gal using data in uncoded units

Term Coef Constant 104.520 Feedstock price $/ton 1.94636 Enzyme cost c/gal ETOH 1.03137 contamination % 0.513596 Sugar loss %SOT -0.0294059 Xylan to Xylose yield % -0.183356 Xylose to ethanol yield % -0.0869187 Minor sugar yield % 0.123201 Feedstock price $/ton* 0.000034794 Enzyme cost c/gal ETOH Feedstock price $/ton* 0.0108429 contamination % Feedstock price $/ton* 9.57699E-05 Sugar loss %SOT Feedstock price $/ton* -0.00544346

## Xylan to Xylose yield % Feedstock price $/ton* -0.00310065 Xylose to ethanol yield % Feedstock price $/ton* -9.72426E-04 Minor sugar yield % Enzyme cost c/gal ETOH* 0.00106179 contamination % Enzyme cost c/gal ETOH* 0.000028986 Sugar loss %SOT Enzyme cost c/gal ETOH* -3.01962E-04 Xylan to Xylose yield % Enzyme cost c/gal ETOH* -8.53226E-05 Xylose to ethanol yield % Enzyme cost c/gal ETOH* 0.000117032 Minor sugar yield % contamination %*Sugar loss %SOT 0.00138582 contamination %* 0.00017280 Xylan to Xylose yield % contamination %* 0.00418919 Xylose to ethanol yield % contamination %*Minor sugar yield % -0.00356814 Sugar loss %SOT* 0.000261026 Xylan to Xylose yield % Sugar loss %SOT* 0.000291600 Xylose to ethanol yield % Sugar loss %SOT*Minor sugar yield % -1.79394E-04 Xylan to Xylose yield %* -6.06842E-04 Xylose to ethanol yield % Xylan to Xylose yield %* -0.00124833 Minor sugar yield % Xylose to ethanol yield %* -7.02483E-04 Minor sugar yield %

Least Squares Means for ETOH cost $/gal

Mean SE Mean Feedstock price $/ton 45.90 135.9 0.008059 60.10 152.4 0.008059 Enzyme cost c/gal ETOH 5 141.6 0.008059 10 146.7 0.008059 contamination % 1 142.9 0.008059 3 145.3 0.008059 Sugar loss %SOT 25 144.0 0.008059 50 144.2 0.008059 Xylan to Xylose yield % 80 147.2 0.008059 90 141.0 0.008059 Xylose to ethanol yield % 80 145.8 0.008059 90 142.4 0.008059 Minor sugar yield % 80 144.7 0.008059 90 143.6 0.008059



# Effects Pareto for ETOH cost $/gal

### AB CE BD BF BG BC BE AD DG EF DE CD FG CG DF CF EG AG AC AF

D AE

G C F B E A



## 1400 1200 1000 800 600 400 200 0Term



## Standardized Effect 2

A Feedstock price $/ton B Enzy me cost c/gal ETO H C contamination % D Sugar loss %SO T E Xy lan to Xy lose y ield % F Xy lose to ethanol y ield % G Minor sugar y ield % Factor Name 

# Pareto Chart of the Standardized Effects (response is ETOH MESP $/gal, Alpha = 0.05)

Alias Structure (up to order 3)
I Feedstock price $/ton Enzyme cost c/gal ETOH contamination % Sugar loss %SOT Xylan to Xylose yield % Xylose to ethanol yield % Minor sugar yield % Feedstock price $/ton*Enzyme cost c/gal ETOH Feedstock price $/ton*contamination % Feedstock price $/ton*Sugar loss %SOT Feedstock price $/ton*Xylan to Xylose yield % Feedstock price $/ton*Xylose to ethanol yield % Feedstock price $/ton*Minor sugar yield % Enzyme cost c/gal ETOH*contamination % Enzyme cost c/gal ETOH*Sugar loss %SOT Enzyme cost c/gal ETOH*Xylan to Xylose yield % Enzyme cost c/gal ETOH*Xylose to ethanol yield % Enzyme cost c/gal ETOH*Minor sugar yield % contamination %*Sugar loss %SOT contamination %*Xylan to Xylose yield % contamination %*Xylose to ethanol yield % contamination %*Minor sugar yield % Sugar loss %SOT*Xylan to Xylose yield % Sugar loss %SOT*Xylose to ethanol yield % Sugar loss %SOT*Minor sugar yield % Xylan to Xylose yield %*Xylose to ethanol yield % Xylan to Xylose yield %*Minor sugar yield % Xylose to ethanol yield %*Minor sugar yield %

# Residual Plots for ETOH cost $/gal

0.2 0.1 0.0 -0.1 -0.2 99.9

99

90

50

10

1

0.1



### ResidualPercent



### 160 150 140 130 0.2

0.1

0.0

-0.1

-0.2

Fitted ValueResidual

0.20 0.15 0.10 0.05 0.00 -0.05 -0.10 -0.15 

### 40

30

20

10

0

ResidualFrequency

1 2 0 1 1 0 1 0 0 9 0 8 0 7 0 6 0 5 0 4 0 3 0 2 0 1 0 1 

### 0.2

0.1

0.0

-0.1

-0.2

Observation OrderResidual 

## Normal Probability Plot Versus Fits

Histogram Versus Order 

# Residual Plots for ETOH cost $/gal

Main Effects Plot for ETOH cost $/gal

60.1 45.9 152

144

136
10 5 3 1

50 25 152

144

136

90 80 90 80

90 80 152

144

136 Feedstock price $/tonMean Enzy me cost c/gal ETO H contamination %

Sugar loss %SO T Xy lan to Xy lose y ield % Xy lose to ethanol y ield %

Minor sugar y ield % 

# Main Effects Plot for ETOH cost $/gal Data Means



# Interaction Plot for ETOH cost $/gal10 5 31 50 25 90 80 90 80 90 80

150

140

130
150

140

130
150

140

130
150

140

130
150

140

130
150

140

130 Feedstock price $/ton

Enzyme cost c/gal ETOH

contamination %

Sugar loss %SOT

Xylan to Xylose yield %

Xylose to ethanol yield %

Minor sugar yield % 45.9 60.1 price $/ton Feedstock

5 10 ETOH c/gal cost Enzyme

1 3 contamination %

25 50 %SOT

loss Sugar

80 90 yield % Xylose Xylan to

80 90 yield % ethanol Xylose to 

# Interaction Plot for ETOH cost $/gal Data Means



# Cube Plot (data means) for ETOH cost $/gal

90 80 90

80 90

80

50 25 3

1 10

5
60.1 45.9

Minor sugar yield % Xylose to ethanol yield % Xylan to Xylose yield %

Sugar loss %SOT contamination % Enzyme cost c/gal ETOH

Feedstock price $/ton 150.564

145.467 129.469 134.566

148.013

142.967 127.262 132.308 150.219

145.175 129.205 134.249

147.760

142.723 127.046 132.083

157.255

152.185 135.400 140.470

154.679

149.575 133.134 138.202 157.007

151.944 135.186 140.249

154.434

149.375 132.925 137.984 154.258

149.200 132.753 137.812

151.715

146.661 130.519 135.573 154.005

148.955 132.536 137.586

151.466

146.421 130.306 135.351

160.934

155.826 138.603 143.711

158.350

153.243 136.338 141.445 160.699

155.599 138.402 143.503

158.107

153.008 136.130 141.228 152.136

147.067 130.875 135.944

149.107

144.063 128.227 133.272 151.428

146.298 130.282 135.324

148.855

143.819 128.011 133.047

158.429

153.319 136.402 141.512

155.735

150.719 134.068 139.130 158.178

153.076 136.187 141.289

155.488

150.435 133.856 138.910 155.427

150.371 133.783 138.840

152.864

147.812 131.532 136.584 155.171

150.123 133.564 138.612

152.702

147.569 131.316 136.449

161.916

156.863 139.501 144.555

159.399

154.345 137.304 142.358 161.677

156.631 139.297 144.343

159.154

154.108 137.094 142.140 

# Cube Plot (data means) for ETOH cost $/gal

# Factorial Fit: Current Yield versus contamination, Sugar loss %, ...

Estimated Effects and Coefficients for Current Yield (Actual/Theoretic (coded units)

Term Effect Coef SE Coef T Constant 0.775719 0.000032 23981.30 contamination % -0.014438 -0.007219 0.000032 -223.17 Sugar loss %SOT -0.001562 -0.000781 0.000032 -24.15 Xylan to Xylose yield % 0.036312 0.018156 0.000032 561.30 Xylose to ethanol yield % 0.020813 0.010406 0.000032 321.71 Minor sugar yield % 0.006437 0.003219 0.000032 99.51 contamination %*Sugar loss %SOT -0.000188 -0.000094 0.000032 -2.90 contamination %* -0.000562 -0.000281 0.000032 -8.69 Xylan to Xylose yield % contamination %* -0.000313 -0.000156 0.000032 -4.83 Xylose to ethanol yield % contamination %*Minor sugar yield % 0.000062 0.000031 0.000032 0.97 Sugar loss %SOT* -0.000437 -0.000219 0.000032 -6.76 Xylan to Xylose yield % Sugar loss %SOT* -0.000187 -0.000094 0.000032 -2.90 Xylose to ethanol yield % Sugar loss %SOT*Minor sugar yield % 0.000188 0.000094 0.000032 2.90 Xylan to Xylose yield %* 0.000938 0.000469 0.000032 14.49 Xylose to ethanol yield % Xylan to Xylose yield %* 0.000563 0.000281 0.000032 8.69 Minor sugar yield % Xylose to ethanol yield %* 0.000312 0.000156 0.000032 4.83 Minor sugar yield %

Term P Constant 0.000 contamination % 0.000 Sugar loss %SOT 0.000 Xylan to Xylose yield % 0.000 Xylose to ethanol yield % 0.000 Minor sugar yield % 0.000 contamination %*Sugar loss %SOT 0.005 contamination %* 0.000 Xylan to Xylose yield % contamination %* 0.000 Xylose to ethanol yield % contamination %*Minor sugar yield % 0.336 Sugar loss %SOT* 0.000 Xylan to Xylose yield % Sugar loss %SOT* 0.005 Xylose to ethanol yield % Sugar loss %SOT*Minor sugar yield % 0.005 Xylan to Xylose yield %* 0.000 Xylose to ethanol yield % Xylan to Xylose yield %* 0.000 Minor sugar yield % Xylose to ethanol yield %* 0.000 Minor sugar yield %

S = 0.000365963 PRESS = 0.0000195918 **R-Sq = 99.98% R-Sq(pred) = 99.97% R-Sq(adj) = 99.97%**

Analysis of Variance for Current Yield (Actual/Theoretical) (coded units)

Source DF Seq SS Adj SS Adj MS F P

## Main Effects 5 0.0641306 0.0641306 0.0128261 95768.40 0.000 2-Way Interactions 10 0.0000643 0.0000643 0.0000064 47.97 0.000 Residual Error 112 0.0000150 0.0000150 0.0000001 Lack of Fit 16 0.0000150 0.0000150 0.0000009 Pure Error 96 0.0000000 0.0000000 0.0000000 Total 127 0.0642099

Estimated Coefficients for Current Yield (Actual/Theoretical) using data in uncoded units

Term Coef Constant 0.488594 contamination % -3.12500E-05 Sugar loss %SOT 0.000250000 Xylan to Xylose yield % 0.00132500 Xylose to ethanol yield % 0.000075000 Minor sugar yield % -9.12500E-04 contamination %*Sugar loss %SOT -7.50000E-06 contamination %* -5.62500E-05 Xylan to Xylose yield % contamination %* -3.12500E-05 Xylose to ethanol yield % contamination %*Minor sugar yield % 6.25000E-06 Sugar loss %SOT* -3.50000E-06 Xylan to Xylose yield % Sugar loss %SOT* -1.50000E-06 Xylose to ethanol yield % Sugar loss %SOT*Minor sugar yield % 1.50000E-06 Xylan to Xylose yield %* 1.87500E-05 Xylose to ethanol yield % Xylan to Xylose yield %* 1.12500E-05 Minor sugar yield % Xylose to ethanol yield %* 6.25000E-06 Minor sugar yield %

Least Squares Means for Current Yield (Actual/Theoretic

Mean SE Mean contamination % 1 0.7829 0.000046 3 0.7685 0.000046 Sugar loss %SOT 25 0.7765 0.000046 50 0.7749 0.000046 Xylan to Xylose yield % 80 0.7576 0.000046 90 0.7939 0.000046 Xylose to ethanol yield % 80 0.7653 0.000046 90 0.7861 0.000046 Minor sugar yield % 80 0.7725 0.000046 90 0.7789 0.000046



# Effects Pareto for Current Yield (Actual/Theoretical)

### CG DF CD DG FG CF DE CE EG EF D G C F E



## 500 400 300 200 100 0Term



## Standardized Effect 2.0

C contamination % D Sugar loss %SO T E Xy lan to Xy lose y ield % F Xy lose to ethanol y ield % G Minor sugar y ield % Factor Name 

# Pareto Chart of the Standardized Effects response is Current Yield (Actual/Theoretical), Alpha = 0.05

Alias Structure
I contamination % Sugar loss %SOT Xylan to Xylose yield % Xylose to ethanol yield % Minor sugar yield % contamination %*Sugar loss %SOT contamination %*Xylan to Xylose yield % contamination %*Xylose to ethanol yield % contamination %*Minor sugar yield % Sugar loss %SOT*Xylan to Xylose yield % Sugar loss %SOT*Xylose to ethanol yield % Sugar loss %SOT*Minor sugar yield % Xylan to Xylose yield %*Xylose to ethanol yield % Xylan to Xylose yield %*Minor sugar yield % Xylose to ethanol yield %*Minor sugar yield %



# Residual Plots for Current Yield (Actual/Theoretical)

### 0.0010 0.0005 0.0000 -0.0005 -0.0010 99.9

99

90

50

10

1

0.1



### ResidualPercent



### 0.82 0.80 0.78 0.76 0.74 0.0010

0.0005

0.0000

-0.0005

-0.0010

Fitted ValueResidual

0.0008 0.0004 0.0000 -0.0004 -0.0008 -0.0012 

### 48

36

24

12

0

ResidualFrequency

1 2 0 1 1 0 1 0 0 9 0 8 0 7 0 6 0 5 0 4 0 3 0 2 0 1 0 1 

### 0.0010

0.0005

0.0000

-0.0005

-0.0010

Observation OrderResidual 

## Normal Probability Plot Versus Fits

Histogram Versus Order 

# Residual Plots for Current Yield (Actual/Theoretic

Main Effects Plot for Current Yield (Actual/Theoretical)

3 1 0.79

0.78

0.77

0.76

50 25 90 80

90 80 0.79

0.78

0.77

0.76

90 80 contamination %Mean 

### Sugar loss %SOT Xylan to Xylose yield %

Xylose to ethanol yield % Minor sugar yield % 

# Main Effects Plot for Current Yield (Actual/Theoretical) Data Means



# Interaction Plot for Current Yield (Actual/Theoretic50 25 90 80 90 80 90 80

0.800

0.775

0.750

0.800

0.775

0.750

0.800

0.775

0.750

0.800

0.775

0.750 contamination %

Sugar loss %SOT

Xylan to Xylose yield %

Xylose to ethanol yield %

Minor sugar yield % 

### 1 3 contamination %

25 50 %SOT Sugarloss

80 90 yield % Xylose Xylan to

80 90 yield % ethanol Xylose to 

# Interaction Plot for Current Yield (Actual/Theoretical) Data Means

Cube Plot (data means) for Current Yield (Actual/Theoretical)

90

80

90 80 90

80 50

25

3 1 Minor sugar yield %

Xylose to ethanol yield % Xylan to Xylose yield % Sugar loss %SOT

contamination % 0.800

0.802 0.817 0.815

0.763

0.764 0.778 0.777 0.778

0.780 0.794 0.793

0.743

0.744 0.758 0.757

0.791

0.795 0.810 0.808

0.757

0.758 0.772 0.771 0.772

0.773 0.788 0.786

0.737

0.739 0.752 0.751 

# Cube Plot (data means) for Current Yield (Actual/Theoretical)