NREL is a national laboratory of the U.S. Department of Energy, Office of Energy Efficiency and Renewable Energy, operated by the Alliance for Sustainable Energy, LLC.

Techno-Economic Analysis and Life-Cycle Assessment 

for Gas Phase Catalytic Oxidation of Lignin to

Produce Phenolic Compounds

Eric C.D. Tan, Ph.D., LCACP

National Renewable Energy Laboratory (NREL), Golden, CO

Tuesday, October 30, 2018

2018 AIChE Annual Meeting, Pittsburgh, Pennsylvania

NREL/PR-5100-72613
2

This work was authored by Alliance for Sustainable Energy, LLC, the 

manager and operator of the National Renewable Energy Laboratory for the 

U.S. Department of Energy (DOE) under Contract No. DE-AC36-08GO28308. 

Funding provided by the U.S. Department of Energy Office of Energy 

Efficiency and Renewable Energy Bioenergy Technologies Office. The views 

expressed in [this presentation] do not necessarily represent the views of the 

DOE or the U.S. Government. The U.S. Government retains and the publisher, 

by accepting the article for publication, acknowledges that the U.S. 

Government retains a nonexclusive, paid-up, irrevocable, worldwide license 

to publish or reproduce the published form of this work, or allow others to 

do so, for U.S. Government purposes. 

Disclaimer
3

Fuel co-products are integral to biorefinery economics

Products Amount of 

Biomass Carbon 

to Product

Conversion Cost Product Value

Liquid fuels (e.g., 

gasoline, diesel, 

aviation)

High $$$ $

Chemicals Lower $$$ $$$
4

Biomass Constituents for Selected Plant Resources

Source: Ragauskas, et al., Science, 344 (2014) http://science.sciencemag.org/content/344/6185/1246843.full

 Lignin constitutes a large 

fraction of biomass

 ~15-30% of biomass 

mass

 ~40% of biomass carbon
5

Biomass Grand Challenge: Complex Functionality

Reactions

Decarbonylation

Decarboxylation

Cracking

Hydrogenation

Hydrogenolysis

Ring Opening

Alkylation

Oligomerization

Multi-functional catalysts are required to convert biomass into fuels 

Fuels - CnH2n+2

Gasoline

Diesel

Jet Fuel

Biomass - CH1.4O0.6

Cellulose

Hemicellulose

Lignin

Pyrolysis

Gasification

Thermochemical

Pathways

Biochemical

Pathways

Enzymatic 

hydrolysis

Fermentation

Biological or 

catalytic 

upgrading
6

Lignin: Fuel vs. Feedstock

Lignin

Boiler

Steam 

turbine

Generator

Transformer

Electrical grid

¢¢¢

Heat & Power

$$$

High-value Chemicals
7

Source: De Wild, et al., Biofuels, Bioprod. Bioref. 8, 645-657 (2014).

Potential Market Applications for Lignin and Lignin-Derived 

Products
8

Lignin Valorization Pathways

Source: Linger, et al. Proc. Natl. Acad. Sci., 2014. 

Using a “funneling” pathway inherent in nature, NREL 

researchers show that lignin can be converted into 

renewable fuels, chemical, and materials.

Thermochemical Route

Biological Route
9

Selective oxidation of lignin showing some potential co-products and 

their markets. The focus of this study is phenol, shown in red.

Selective 

Oxidation Lignin Pyrolysis Simple

Phenols

Muconic Acid

Phenol

Polycarbonates and Resins

Cresols

Chemicals, Pharmaceuticals, Resins

Maleic Anhydride 

Unsaturated Polyester Resins

Terephthalic Acid

PET and Polyesters

Adipic Acid

Nylon and Polyurethane

Benzene diols, Quinones

Specialty Chemicals

Goal: Convert lignin to valuable phenolic compounds

Lignin pyrolysis → partial oxidation of lignin to remove methoxy side chains → create “simple phenols” 

(phenols with no methoxy groups)

Scope: Preliminary TEA and LCA evaluation

Illustration of simple phenols as 

intermediates to various chemical 

products... 
10

Hydrocarbon production via lipid pathway, with valorization of lignin through 

the fast pyrolysis and subsequent gas phase selective oxidation to phenols.

For TEA and LCA, we have developed and modeled this hybrid process: 

1) biochemically converting C5/C6 sugars from biomass to a hydrocarbon blendstock, and 

2) thermochemically converting lignin from biomass, via selective partial oxidation of lignin 

pyrolysis vapor, to phenols. 
11

LIGNIN FROM BIOCHEM. PROCESS

LIGNIN PYROLYSIS 

PRODUCTS

Pyrolysis

CO and CO2

(undesired oxidation 

products) OH OH

phenol cresol(s) catechol

SIMPLE PHENOLS

Catalytic partial 

oxidation

Char

(recalcitrant C-C 

linkages in lignin)

Oxidative removal of lignin-chains for co-products

Vanadia-based 

catalysts

Paper 695a

Thursday, 11/1/2018 

at 3:30 PM
12

Conversion Technology Assessment

 Techno-economic analysis (TEA)

Assess the technical and economic viability of new processes and 

technologies (MFSP)

 Life-cycle assessment (LCA)

Estimate the environmental impacts (GHGs)
13

TEA Methodology & Assumptions

Discounted Cash Flow Analysis Parameters

Chemical Engineering’s 

Plant Cost Index 

Plant life 30 years

Discount rate 10%

General plant depreciation 7-year MACRS schedulea

Steam plant depreciation 20-year MACRS schedulea,b

Federal tax rate 35%

Financing 40% equity

Loan terms 10-year loan at 8% APR

Construction period 3 years

First 12 months’ expenditures 8%

Next 12 months’ expenditures 60%

Last 12 months’ expenditures 32%

Working capital 5% of fixed capital investment

Start-up time 6 months

Revenues during startup 50%

Variable costs incurred during startup 75%

Fixed costs incurred during startup 100%

a https://www.irs.gov/pub/irs-pdf/p946.pdf b For the case with no electricity selling, the steam plant is depreciated using the 7-yr basis instead of 20-yr basis. 

Costs in 2014$
14

Capital cost breakout

Lignin to Heat & Power 

(no coproduct)

Lignin Valorization 

(Coproduct: phenols)

Costs in 2014$
15

Preliminary TEA Results

17% MFSP improvement from valorization of lignin

Phenols coproduct value: $1,981/tonne (2010-2014 5-yr average from IHS)

Note: The $7.80/GGE MFSP number for the pathway (via lipids) was presented in the DOE Bioenergy Technologies Office 

(BETO) 2017 Project Peer Review (March 7, 2017, Denver, CO) 

(https://www.energy.gov/sites/prod/files/2017/05/f34/Biochemical%20Platform%20Analysis%20Project_0.pdf, see slide 11).

Costs in 2014$
16

LCA Methodology & Assumptions

1. Goal

• Preliminary life cycle GHG intensity assessment

• Compare the base case, lignin used for heat and power generation, with the 

case with lignin valorization (producing coproduct)

• Not intended to be used in comparative assertions

2. Scope

• Functional unit: 1 MJ of RDB

• System boundary: “field-to-wheel”

• Allocation: coproduct displacement

• Impact assessment method: 

 Single attribute LCA

 IPCC 2013 GWP 100a

3. Life Cycle Inventory

• Biorefinery – Aspen Plus process model

• Upstream & downstream – GREET

• Others – USLCI, EIO, Ecoinvent

Bioenergy Supply Chain

*Modified from figure obtained from 2016MYPP.
17

Preliminary LCA Results

Lignin valorization potentially lowers life cycle carbon intensity (16% improvement)

Petroleum-based phenols (Hock process) GHG intensity: 4.14 kg CO2e/kg
18

LCA – Coproduct Allocation Sensitivity

Allocation 

Methods

Product / 

Coproduct Units

Lignin To Heat & 

Power

Lignin To 

Coproduct

Allocation 

Factor

RDBa kg/hr 8603 8603 74.2%

Coproduct kg/hr 0 2994 25.8%

RDB MM$/yr 74.21 74.21 61.3%

Coproduct MM$/yr 0.00 46.77 38.7%

RDB % 19.8% 19.8% 76.4%

Coproduct % 0% 6.1% 23.6% a

 RDB: Renewable Diesel Blendstock

b

 System-level allocation. RDB at $3.00/GGE. Coproduct (phenols) at $1981/tonne.

Mass

Market valueb

Carbon efficiency

Reference: Cai, et al., Biofuels, Bioprod. Bioref. 

12, 815-833 (2018). 
19

Summary

 NREL has developed a vapor phase selective oxidation process for the 

conversion of insoluble lignin streams from the biological biofuels production 

into phenols.

 As illustrated using an NREL’s biological conversion of C5/C6 sugars to 

renewable diesel blendstock via lipid upgrading, lignin valorization has 

improved the economics by 17%.

 Lignin valorization has also had the potential to lower the life cycle carbon 

intensity of the biofuel (16% improvement) when coproduct (phenols) is 

handled using displacement approach (a.k.a system expansion). 

 Coproduct displacement is the default coproduct handling approach under the 

current policy framework that allows the biorefinery to be credited for 

producing chemical coproducts with fewer GHG emissions than their 

petroleum counterparts. 

 Coproduct handling approach sensitivity analysis has revealed that the life- cycle GHG emissions readily vary with the coproduct handling method. This 

should be examined at the interpretation phase of the LCA study.
20

National Bioenergy Center

Matt Yung (coauthor)

Calvin Mukarakate (coauthor)

Mark Nimlos (coauthor)

Michael Griffin (coauthor)

Seonah Kim (coauthor)

Ryan Davis

Mary Biddy

Abhijit Dutta

Speaker information:

Eric.Tan@nrel.gov

(303) 384-7933

http://www.nrel.gov/biomass

DOE’s Bioenergy Technologies Office (BETO)

http://www.eere.energy.gov/biomass

Acknowledgements