Modeling Biomass Conversion to

Transportation FuelsJacob Miller

Advisor: Dr. Eric Larson

OutlineWhat is biomass? Why is it useful?

What is bioconversion?

What is biomass made of?

Manufacturing process

Model creation: Mass, energy, and carbon balances

Economic modeling, carbon and energy credits

Final cost estimates

What is biomass?Yes No

Switchgrass

Corn Stover

Corn

Soybeans

Inedible plant matter

Bioconversion

Rubin, 2008

1

2

Components of BiomassWhat we care about:

Cellulose, lignin, hemicellulose

Alonso et al. 2012

Enzymatic hydrolysis, bioconversionto fuels

Pretreatment,bioconversion to fuels

Burned for electricity

3 Core ProcessesPretreatment: Separate hemicellulose and lignin

from cellulose, depolymerize hemicellulose (in some cases)Common methods: dilute acid, steam, ammonia

Hydrolysis: break cellulose up into individual glucose monomersMethod: enzymes (biological catalysts)

Bioconversion: converts sugars to fuel moleculesCommon example: fermentation of glucose

to ethanol

Model Basis: NREL Model

Davis et al. 2013

Process units altered slightly in various scenarios

Model Creation: Mass, Energy, and Carbon

Balances

Mass flows, kg/hr=Process CO2 outlets

Final Cost Estimates Sample

MFSP: Minimum fuel selling priceTakeaway: cellulosic biofuels won’t be economical without high

CO2 taxes

Plant Configurations

AcknowledgementsPrinceton Environmental Institute

Dr. Eric Larson, Dr. Thomas Kreutz, Dr. Robert Williams, Dr. Hans Meerman, Maurizio Spinelli

Questions?

Economic Modeling, Carbon and Energy

CreditsDiscounted Cash Flow Analysis

External power source/replacement: Natural gas combined cycle plant

CO2 tax: $0-$100/ton

Components of Biomass

Plant% Dry Mass

Cellulose

% Dry Mass Hemicellulos

e

% Dry Mass Lignin

% Dry Mass Other

Sugarcane bagasse 35.2 24.5 22.2 18.1Switchgrass 35.2 30.5 7.7 26.6

Corn stover 34.4 22.8 18 24.8

Rezende et al. 2011Godin et al. 2013Kumar et al. 2009

Carbon Capture Integration

RectisolLess expensive ($1s million capital costs)Can only capture CO2 from pressurized sources

Amine SolventMore expensive ($100s million capital costs)Can capture CO2 from any emissions source (ex:

biomass generator)