Co-producing Biofuels and Animal Feeds at Regional

Biomass Processing Depots

Bryan BalsMichigan State University

Presented at Frontiers in Biorefining10/20/2010

Not asking the right questionsWe cannot force bioenergy into the current agricultural landscape and expect it to work

Agriculture has changed before; it can change again

We must examine the actual uses of land rather than relying on intuitive “gut reactions”

Most agricultural land is used for animal feed, NOT direct human consumptionCropland is currently not used efficiently; we actually have more than enough land

Solution: new technologies for better animal feed and improved productivity of land

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Questions for a Biofuels Future

Premise: the cellulosic biofuels industry will grow rapidly in the coming decades.While we build the first plants & set up the first supply chains, let us remember what the ultimate system will look like and keep the following questions in mind:

How can uniform, reproducible supply chains develop?How can we commoditize biomass?How can we improve the environmental performance of our systems?Given a large biofuel demand, what are the implications for food/feed/fiber markets? Can we coproduce fuels (& foods/feeds)?How can farmers & local communities benefit?

Attacking Biomass Supply Challenges: Regional Biomass Processing Depots (RPBDs)

Partners:Iowa State U.

Idaho National Lab.Pennsylvania State U.

Michigan State U.

Objective: convert regional, distinct biomass sources into dense, stable,

shippable intermediate commodities for later upgrading at (bio)refinerie

Advantages of RBPDsAddress biomass variability near point of productionProduce dense, stable, shippable intermediate commodities for biofuel producers (“biorefineries”)Reduce transaction costs & capital risks for biorefineriesBenefit rural communities through job creation & ownership Address “food vs. fuel” and sustainability issues directly

Research needs to implement RBPDsOptimize in field harvest/storage/logistical systemsOptimize supply chain for “best” intermediate productsConduct technoeconomic and life cycle studies Develop processing technology/property data for biofuelintermediates & coproducts (eg, biochar, animal feeds)

Advantages and R&D Needs for Regional Biomass Processing Depots

Sustainable rural economies + Sustainable

biofuels

RBPC System Effect 1 – Larger

Biorefineries in high yield areas

Effect 2 – biorefiners in remote rural areas

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AFEX-Treated Fibrous FeedsProblem: Energy in the form of cellulose

Early Forages – low yields, expensiveLate Forages – indigestible, low nitrogen

Partial solution: Gaseous ammoniationOnly modest improvements in digestibility seenIncreases nitrogen content

AFEX – Ammonia Fiber ExpansionA leading pretreatment for biofuels via sugar platformBetter fiber disruption than conventional ammoniation for forages—better animal feed

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Reactor Explosion

AmmoniaRecovery

BiomassTreatedBiomass

RecycleAmmonia

GaseousAmmonia

Reactor Expansion

AmmoniaRecovery

BiomassTreatedBiomass

AmmoniaGaseousAmmonia

Heat

AFEX Process Overview

AFEX process description and properties•hot, concentrated (~15M) ammonia:water mix, short rxn time

•rapid pressure release ends treatment, cools system•little biomass degradation, high yields, residual ammonia value

•no separate liquid phase (“dry to dry”)—very high solids loadings possible

•Typical process conditions•Pressure 20-30 atm

•Temperature 70-140 C•Residence time 5-10 minutes

•Ammonia: dry biomass loading (0.3 -2.0 to 1) (w/w)•Water: dry biomass content (0.2 – 2.5 to 1) (w/w)

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Total Digestible Nutrients, Net Energy for Lactation, and Crude Protein

TDN NEL CP

% DM Mcal/lb % DM

Corn grain 88.7 0.91 9.4

Corn silage 68.8 0.66 8.8

Orchardgrass hay 63.1 0.62 18.1

Alfalfa hay 58.9 0.58 20.2

AFEX Corn Stover 75.6 0.79 17.2

AFEX Switchgrass - late 63.0 0.67 14.6

All values except AFEX materials obtained from Nutrient Requirements of Dairy Cattle, NRC 2001

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Economics

NCSU UWisc Average

AFEX Corn Stover $182 $151 $167

AFEX Switchgrass $153 $132 $143

Alfalfa Hay $176 $160 $168

Corn Grain $145

Soybean Meal 48% $320

Expected corn stover production costs: $40-50/ton

Increase value by over $100/ton

AFEX Biomass Pellets: No Binder

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Bulk density: 6 pounds/cubic foot

Bulk density: 50 pounds/cubic foot

Estimated cost to pellet: $5-10/ton (per Federal Machine, Fargo, ND)

Leaf Protein Concentrates

Crop Average Yield(tons/acre/year)

Protein Content(dry mass %)

Protein Produced(tons/acre/year)

Switchgrass 5.0 – 10 5 - 10% 0.25 – 1.0Soybeans 1.2 – 1.4 40% 0.5 – 0.6Alfalfa 3.7 – 5.0 20 - 25% 0.8 – 1.2Mixed forages 3.3 – 4.6 15 – 25% 0.5 – 1.2Double crop 1.0 - 2.5 10 - 20% 0.1 - 0.5

Leaf protein readily abundant, but trapped with indigestible fibrous material

Solution: separate protein from fiberLeaf protein replaces soy meal & is more land efficient

Fiber can be used for ethanol production Successfully produced at commercial scales

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Economics of leaf protein production

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The Regional Biomass Processing Center (RBPC) Approach

ProteinRecovery

ProteinExtraction

Protein

Grinding Hydrolysis/FermentationPretreatment

Distillation

Ethanol

Ammonia

Whey

Enzymes

Solubles

RBPC

ForageFeed

Fast Pyrolysis

Low temperature rapid burning of biomass without oxygenUp to 75% of biomass by weight becomes oil

Fast Pyrolysis – Bio-oil

Bio-oil: main output of fast pyrolysisAcidic mixture of aldehydes, carboxylic acid, lignins, water, and other componentsLow viscosity liquid

Suitable for standalone diesel engines, can be upgraded to renewable diesel with hydrogen additionMajor setback – corrosive, unstable

Add alkaline material at RBPD, stabilizers before shipping to oil refinery

Biochar – Co-product

Solid, carbon rich residue of fast pyrolisisprocess

Used as fertilizer supplementAlternate #1: Burn/Digest for energyAlternate #2: Activated carbon

Integration into RBPD

Waste heat – 500 – 600CProvide heat integration for AFEX, drying, and other

Biochar – anaerobic digestion?Alternate form of steam or powerIntegrate with farms for soil organic carbon

Diversify feedstocksWoody materials for pyrolysisGrasses for AFEX treatment

Anaerobic digestion

Take in excess manure from surrounding animal farms

Provide methane for heat/electricity for remaining operationsTake in excess biomass when other operations are inoperable/at capacitySell excess methane?

Advanced #1) Enzymes

AFEX-treated biomass is rich in nutrients and adequate for fermentationPossible to produce oligomers that can stimulate cellulase and hemicellulaseproduction

Option 1) In-house enzyme productionOption 2) Commercial enzyme production

Enzyme production

AFEX-CS Lactose0

2

4

6

8

Suga

r Con

cent

ratio

n (g

/L)

Materials Used for Induction (on the same sugar weight basis)

0 1 2 10 (Std Mix)0

2

4

6

8

10

12

14

16

18

Exogenous Enzyme Addition (mg/g CS)

Olig Xyl Olig Glc Cellobiose Mon Xyl Mon Glc

1:6 diluted T. reseei broth

Advanced #2) N-based chemicals

Already extracting protein from biomassProtease digestion of proteinCurrent work – wheat stillage

14.4% solids28% protein (solids only): ~18% initially soluble0.1, 1.0% protease loading (g/g solids) – Protex14L, 6L24h residence time at 50C

Effectiveness of different proteases

0

10

20

30

40

50

60

70

6L 14L 51P 14L/51P

Per

cen

t so

lub

ilize

d (

%)

Protein SolubilizedMass Solubilized

Protease Digestion – Protein balance

0%

3%

6%

9%

12%

15%

18%

ALA ARG ASX GLY HIS ILE LEU LYS PHE PRO THR TYR VAL

Protex 6Luntreated - solubleuntreated

Possible End Product - Cyanophycin

Cyanophycin – produced via fermentationFinal products – acrylonitrile, acrylamide

Konst et al., Green Chemistry 2009, 11:1646

Key Points

Biomass supply issues are key to producing a strident cellulosic biorefinery industryMultiple technologies can combine in a small scale – Regional Biomass Processing DepotsAnimal feeds are a near term co-product to making biofuel production profitable

Also eliminate the “Food vs Fuel” argument

Such RBPDs are amenable to upgrading to future value-added products as well

Biomass Conversion Research Laboratory

www.glbrc.org 28