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Evaluation of a Flowthrough Reactor for Corn Stover Pretreatment

Evaluation of a Flowthrough Reactor for Corn Stover Pretreatment. Chaogang Liu, Charles E. Wyman Thayer School of Engineering Dartmouth College Hanover, New Hampshire 03755 AIChE Annual Meeting Indiana Convention Center Indianapolis, Indiana November 4, 2002. Biomass Refining CAFI.

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Evaluation of a Flowthrough Reactor for Corn Stover Pretreatment

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  1. Evaluation of a Flowthrough Reactor for Corn Stover Pretreatment Chaogang Liu, Charles E. Wyman Thayer School of Engineering Dartmouth College Hanover, New Hampshire 03755 AIChE Annual Meeting Indiana Convention CenterIndianapolis, Indiana November 4, 2002 Biomass Refining CAFI

  2. USDA IFAFS Project Overview • Multi-institutional effort funded by USDA Initiative for Future Agriculture and Food Systems (IFAFS) Program to develop comparative information on cellulosic biomass pretreatment by leading options with common source of cellulosic biomass • Aqueous ammonia recycle pretreatment - YY Lee, Auburn University • Water only and dilute acid hydrolysis by co-current andflowthrough systems - Charles Wyman, Dartmouth College • Ammonia fiber explosion - Bruce Dale, Michigan State University • Controlled pH pretreatment - Mike Ladisch, Purdue University • Lime pretreatment - Mark Holtzapple, Texas A&M University • Logistical support and economic analysis - Rick Elander/Tim Eggeman, NREL Biomass Refining CAFI

  3. Flowthrough (FT) Pretreatment • Flows just hot water or very dilute acid solution through stationary biomass • Removes large fraction of hemicellulose and lignin • Separates sugars from solids, reducing decomposition • Achieves high cellulose digestibility • Uses less chemicals than co-current process • Provides a less corrosive environment • However, high amounts of water are needed, increasing energy for pretreatment and recovery Biomass Refining CAFI

  4. Background on FT • Bobleter and his coworkers were pioneers in the study of flowthrough biomass pretreatment • Antal, Lee, and Sakaki extended and improved flow treatment with just water • Torget et al showed similar performance with very dilute acid concentrations in unique flowthrough configurations Biomass Refining CAFI

  5. How are FT and Batch Different ? Batch FT Xylose yield <90% ~100% Lignin removal <10% >50% Digestion yield <90% ~100% (by SSF) Digestion time 7 days ~2 days (by SSF) Biomass Refining CAFI

  6. Objectives of This Study • Evaluate effects of flow rate, temperature, and acid concentration on solubilization of hemicellulose and lignin in a flowthrough reactor • Particularly focus on developing detailed time profiles on the fate of major biomass components • Investigate how fluid velocity and liquid-solid contact time impact performance • Seek to understand reasons for differences between batch and flowthrough systems and gain new insight into hemicellulose hydrolysis mechanisms • Provide knowledge from which to develop advanced systems that combine the best features of each while overcoming their limitations Biomass Refining CAFI

  7. Presentation in Context of USDA IFAFS Project Tasks • Apply leading pretreatment technologies to prepare biomass for conversion to products • Characterize resulting fluid and solid streams • Close material and energy balances for each process • Determine cellulose digestibility and liquid fraction fermentability • Compare performance of pretreatment technologies Biomass Refining CAFI

  8. Corn Stover Composition • NREL supplied corn stover to all project participants (source: BioMass AgriProducts, Harlan IA) • Stover washed and dried in small commercial operation, knife milled to pass ¼ inch round screen Biomass Refining CAFI

  9. Schematic of Flowthrough System Sample Biomass Refining CAFI

  10. Flowthrough Reactors Gasket Filter 120mm 1/2-in, O.D. 180mm 60mm 1/2-in, O.D. 1-in, O.D. 3/4-in, O.D. To vary contact time at constant velocity To vary velocity at constant contact time Biomass Refining CAFI

  11. Effect of Flow Rate and Temperature on Residual Xylose for Water Only Biomass Refining CAFI

  12. Effect of Flow Rate and Temperature on Residual Xylose for Water Only Biomass Refining CAFI

  13. Effect of Flow Rate and Temperature on Residual Xylose for Water Only Biomass Refining CAFI

  14. Effect of Flow Rate and Acid on Residual Xylose at 180oC Biomass Refining CAFI

  15. Effect of Flow Rate and Acid on Residual Xylose at 180oC Biomass Refining CAFI

  16. Effect of Flow Rate and Acid on Residual Xylose at 180oC Biomass Refining CAFI

  17. Effect of Flow Rate on Total Xylose Yield at 180oC after 16 minutes Biomass Refining CAFI

  18. Xylose Solubilization for Water Only and 0.1wt% Sulfuric Acid at 180oC and a Flow Rate of 10mL/min Biomass Refining CAFI

  19. Xylose Solubilization for Water Only and 0.1wt% Sulfuric Acid at 180oC and a Flow Rate of 10mL/min Biomass Refining CAFI

  20. Change in Lignin Removal with Flow Rate for Water Only and Sulfuric Acid after 16 minutes at 180oC Biomass Refining CAFI

  21. Solubilization of Xylan and Lignin for Water Only Hydrolysis Biomass Refining CAFI

  22. Change in Lignin Removal with Liquid-Solid Contact Time for a Flow Rate of 10mL/min with 0.05wt% Sulfuric Acid at 180oC Biomass Refining CAFI

  23. Change in Lignin Removal with Fluid Velocity for 0.05wt% Sulfuric Acid Pretreatment at 180oC and a Flow Rate of 10mL/min Biomass Refining CAFI

  24. Material Balance Slide at 60 FPU/g Biomass Refining CAFI

  25. Material Balance Slide at 15 FPU/g Biomass Refining CAFI

  26. Material Balance Slide for SSF Biomass Refining CAFI

  27. Summary • Flow rate acts somewhat like temperature and acid in effect on solubilization of hemicellulose and lignin • Increase in xylan removal with flow rate or velocity is inconsistent with traditional first order kinetic models suggesting that simple hydrolysis is not the only factor in hemicellulose removal • Data relating lignin and hemicellulose removal and on effects of contact time support idea that lignin reacts and precipitates with time Biomass Refining CAFI

  28. Acknowledgements • The United States Department of Agriculture Initiative for Future Agricultural and Food Systems Program through Contract 00-52104-9663 for funding our research • The United States Department of Energy Biofuels Program and the National Renewable Energy Laboratory • Our partners from Auburn University, Michigan State, Purdue, and Texas A&M Universities and the National Renewable Energy Laboratory • The Thayer School of Engineering at Dartmouth College Biomass Refining CAFI

  29. Questions? Biomass Refining CAFI

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