Breaking the Chemical and Engineering Barriers to Lignocellulosic Biofuels

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Conrad Willis
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1 Breaking the Chemical and Engineering Barriers to Lignocellulosic Biofuels A Workshop to Develop the Roadmap for Making Lignocellulosic Biofuels a Practical Reality ACS Headquarters Washington, D.C. June 25-26, 2007

2 Current Situation in Biofuels 20 in 10 mandate (35 billion gallons of alternate fuel by 2017) DOE/USDA estimates for 2017*: billion gallons ethanol from corn 2-5 billion gallons ethanol from cellulose Total: billion gallons, about that needed * Valerie Reed, Office of Biofuels Program, DOE

3 What can catalysis and engineering do? Current paradigm: Enzyme hydrolysis of biomass, fermentation for ethanol Gasification or pyrolysis of recalcitrant cellulose What other processes are there?

5 Potential advantages of hydrocarbons

6 Potential advantages of hydrocarbons Self-separate; remove great expense of distillation

7 Potential advantages of hydrocarbons Self-separate; remove great expense of distillation ~30% higher energy density; won t t suffer a commensurate loss of gas mileage

8 Thermodynamics: Energy Density: Gasoline: 104,000 Btu/gallon Ethanol: 70,300 Btu/gallon E85: 75,400 Btu/gallon (72% of gasoline) The higher octane number of ethanol gives rise to an incremental improvement in engine efficiency (Otto cycle) Incremental improvement in engine performance will not make up for much lower energy density 104 Btu x 0.3 = 31.2 Btu output; 75.4 x 0.32 = 24.1 Btu output (23% lower than gasoline) Much misleading information in the media

9 The fine print: The overall fuel consumption of the current Saab 9-5 BioPower engine using E85 is about 30 percent higher than on gasoline and the optimized BioPower 100 engine is expected to yield a near 10 percent gain against this...

10 Potential advantages of hydrocarbons Self-separate; remove great expense of distillation ~30% higher energy density; won t t suffer a commensurate loss of gas mileage Reduction of water use

11 Potential reduction of process water Gasification and pyrolysis Dumesic/Wisconsin: 30-50% sugar solutions Zhang, White/PNNL: Ionic liquids

Potential advantages of hydrocarbons Self-separate; remove great expense of distillation ~30% higher energy density; won t t suffer a commensurate loss of

12 Potential advantages of hydrocarbons Self-separate; remove great expense of distillation ~30% higher energy density; won t t suffer a commensurate loss of gas mileage Reduction of water use Green gasoline/diesel/jet fuel fit into current infrastructure; no need for engine modifications or new distribution systems

13 Summary Green gasoline (and jet fuel and diesel) with catalysis is a viable paradigm to explore Ethanol is a good additive to gasoline at 10% and can meet the 2012 energy mandate However, society will strongly resist an alternate fuel that costs more and gives substantially lower gas mileage; E85 is currently problematic Green gasoline may be a long term solution

14 Biomass Feedstocks Cellulosic Biomass (wood, wood wastes, corn stover, switch grass, agricultural waste, straw, etc.) Chemical Structure: cellulose, hemicellulose, lignin Corn Stover Bagasse Corn Sugarcane Strategies for Biofuel Production Triglycerides (Vegetable Oils, Algae) Corn Grain Gasification Fast Pyrolysis Liquefaction Pretreatment & Hydrolysis Hydrolysis Bio-oils (Sugars, Acids, Aldehydes, Aromatics) Lignin (coumaryl, coniferyl and sinapyl alcohols) C5 Sugars (Xylose) C6 Sugars (Glucose, Fructose) Water-gas shift MeOH Synthesis Syn-gas CO + H2 Fischer-Tropsch Synthesis Steam-Reforming Sucrose (90%) Glucose (10 %) Dehydration Alkyl esters (Bio-diesel) Transesterification C 1 -C 14 Alkanes/Alkenes Zeolite/Pyrolysis C Hydrodeoxygenation 12 -C 18 n-alkanes Direct Use Blending/Direct Use Hydrodeoxygenation Zeolite Upgrading Emulsions Hydrodeoxygenation Zeolite upgrading Furfural C6 Sugars Dehydration All Sugars Hydrogen Methanol Alkanes Gasoline Aromatics, hydrocarbons Aromatics, light alkanes, coke Direct Use Alkyl benzenes, paraffins Aromatics, coke Olefins C 8 -C 13 n-alkanes, Alcohols Aqu. Phase Proc. MTHF (Methyltetrahydrofuran) Hydrogenation Levulinic Levulinic Esters Esterification Acid MTHF Hydrogenation Ethanol, Butanol Fermentation APD/H C 1 -C 6 n-alkanes Aromatics, alkanes, coke Zeolite Hydrogen Aqueous or S.C. Reforming Key: Black - Chemical Conversion Green - Biological Conversion Blue - Both Chemical & Biological Conv. G.W. Huber, S. Iborra, A. Corma; Synthesis of Transportation Fuels from Biomass: Chemistry, Catalysts, and Engineering, Chemical Reviews 106, 4044 (2006).

15 Current paradigm: Enzyme hydrolysis of biomass, fermentation for ethanol Gasification or pyrolysis of recalcitrant cellulose Possible additional paradigms: Total gasification/fts Total pyrolysis,, APR of pyrolysis oil Hydrolysis of biomass, APR of sugar, pyrolysis of RC for green gasoline, green diesel, green jet fuel, chemicals

16 Potential Workshop/Roadmap Impact Immediate interest of media Late summer Capital Hill briefing (ASME Briefing Series) Fall Biofuels Summit Possible NSF/ENG Emerging Frontiers in Research and Innovation (EFRI) topic (= $10 million) Possible NSF-wide Hydrocarbon Biorefineries topic: Transformational paradigm for alternate energy Much depends on our cohesiveness and the quality of our writing!!!

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