biochemical processing integration

1. Biochemical Processing Integration Biochemical Platform Review Meeting Daniel Schell NREL August 7-9, 2007

2. Overview Project start date: FY2001 Project end date: FY2012 Barriers addressed Biological process integration Biomass variability Biochemical/thermochemical processing integration Cleanup/separations Recommended time for this slide: <2 min The purpose of this slide is to provide some context for evaluating your project and especially your accomplishments. The information in the left column describes the magnitude and timing of the investment in your project. The information in the right column describes the players and the issues that are to be overcome. For projects that include multiple partners, please discuss the roles of each and how the overall project is being managed. Include stage from stage gate guide.Recommended time for this slide: <2 min The purpose of this slide is to provide some context for evaluating your project and especially your accomplishments. The information in the left column describes the magnitude and timing of the investment in your project. The information in the right column describes the players and the issues that are to be overcome. For projects that include multiple partners, please discuss the roles of each and how the overall project is being managed. Include stage from stage gate guide.

3. Goals Near-term Goal: Make cellulosic ethanol cost competitive by 2012 Process Target: Competitive, moderate risk bioethanol technology tested at pilot scale (1 ton per day) Cost Target: Data from integrated pilot operation combined with process design & cost estimate validates a $1.31 (2007$) per gallon ethanol selling price

4. Objectives Funds for getting equipment in working order? Distillation has not been used in several years Funds for getting equipment in working order? Distillation has not been used in several years

5. Project Supports and Demonstrates Key Technical Targets

6. Approach Process Integration

7. Process Material Supplied to Industry and Academia in Last Two Years

8. Improve analytical methods for compounds in process streams Accuracy and speed (robotics) for measuring sugars and other products Other important measurements (e.g., total dry solids, insoluble solids fraction) Validate/develop compositional analysis methods for feedstocks Other feedstocks besides corn stover (e.g., switchgrass, etc.) Unknown compounds in biomass extractives Develop/improve rapid compositional analysis methods Intermediate process streams (e.g., in pretreatment reactors or fermentors) On-line measurement and use on other instruments Approach Compositional Analysis Methods

9. Accomplishments

10. Accurate and Reliable Compositional Measurements

11. Developing Tools to Understand Feedstock Composition and Process Chemistry Much of NREL�s research in process development involves developing an understanding of the chemical changes occurring in each step of the process. As an example, this slide illustrates the chemical transformation that occurs during dilute acid pretreatment of corn stover. Remove percentages from pretreated bar. Ask Dan Schell to review TPs. The upper chart shows the major constituents of corn stover prior to pretreatment. After exposure to dilute sulfuric acid, the corn stover is converted into two materials: pretreated corn stover solids and a liquor. The solids retain most of the cellulose and lignin, while the liquor contains most of the constituents from hemicellulose. Hemicellulose is the most reactive component of the three. The pretreatment can be considered a liquefaction of the hemicellulose component. NREL and other labs have developed analytical methods to track these chemical changes. These methods are available on the NREL Web site and are used extensively throughout the industry. The slide shows the pretreated corn stover solids contain most of the cellulose from the starting stover. This solid material is fed in the enzymatic hydrolysis step of most biorefinery stages. Much of NREL�s research in process development involves developing an understanding of the chemical changes occurring in each step of the process. As an example, this slide illustrates the chemical transformation that occurs during dilute acid pretreatment of corn stover. Remove percentages from pretreated bar. Ask Dan Schell to review TPs. The upper chart shows the major constituents of corn stover prior to pretreatment. After exposure to dilute sulfuric acid, the corn stover is converted into two materials: pretreated corn stover solids and a liquor. The solids retain most of the cellulose and lignin, while the liquor contains most of the constituents from hemicellulose. Hemicellulose is the most reactive component of the three. The pretreatment can be considered a liquefaction of the hemicellulose component. NREL and other labs have developed analytical methods to track these chemical changes. These methods are available on the NREL Web site and are used extensively throughout the industry. The slide shows the pretreated corn stover solids contain most of the cellulose from the starting stover. This solid material is fed in the enzymatic hydrolysis step of most biorefinery stages.

12. Making Progress on Measuring Lignin in Pretreatment Solids

13. Developed Faster Analytical Method for Measuring Ethanol and Other Products Fast HPLC analysis of fermentation products and furans Analysis of multiple compounds in under 10 min versus 55 min by old method

14. Using Spectroscopy to Rapidly Measure Biomass Composition Spectra of biomass samples measured in a spectrophotometer Partial least squares analysis used to develop a calibration equation relating spectral information to component concentrations Requires a minimum of 50-100 samples to develop a calibration equation

15. Demonstrated On-line Feedstock Compositional Measurement

16. Transferring NIR Calibrations to Other Instruments

17. Successfully Transferred NIR Model Calibration Equations Calibration Transfer Algorithms attempt to transform the NIR spectra on secondary instruments to �look like� they came from the primary instrument; the more they resemble the primary spectra, the better the calibration transfer We were able to use public-domain calibration transfer algorithms to successfully transfer the corn stover calibration equation between two very different NIR spectrometers

18. Integration Studies Use High Solids Content Hydrolysate Produced in a Pilot Scale Reactor

19. Understanding Process Relevant PerformanceBaseline Integrated Performance Testing

20. Early Findings Sugar losses during conditioning Poor xylose utilization Microorganism limitation or toxicity or both Large amount of remaining glucose As monomers and oligomers Didn�t look at recycle water Large enzyme requirement (40 mg protein/g cellulose)

21. Reduced Sugar Losses During ConditioningEffect of a Different Conditioning Agent Beside reduced sugar losses, ethanol yields increased for NH4OH-based conditioning This simpler process may eliminate the solid-liquid separation step, but chemical cost will increase Represents significant progress toward achieving the 2012 goal of < 1% sugar losses

22. Glucose-xylose fermenting microorganisms are more negatively impacted by increasing hydrolysate strength Performance was slightly better in overlimed hydrolysate than neutralized hydrolysate

23. High ethanol concentrations can be achieved in concentrated hydrolysates Glucose fermenting yeast can achieve good performance in concentrated hydrolysate Still need to achieve higher ethanol yields, performance is being limited Need to take advantage of microorganisms strengths

24. Progress Toward Higher Ethanol Yields

25. Progress Toward Higher Ethanol Yields

26. Good Performance with Water Recycle is a Key Issue Recycle water (stillage bottom stream) is a common method of reducing fresh water use Our economic models assume 25% recycle Performance is significantly affected at modest solid concentrations and recycle water use Other inhibitors in addition to acetic acid are responsible for the poor performance

27. Possible Solutions to Water Recycle Remove acetic acid using membranes Initial effort via subcontract with Colorado State University Remove other inhibitory compounds Initial effort via the MAST Center Other clean up/separations technologies

28. Success Factors and Showstoppers Critical success factors and showstoppers are aligned with Biochemical Platform technical barriers Integration specific issues, i.e., achieving good conversion yields at process relevant operating conditions Operating at high solid concentrations Minimizing water use (recycle water) Minimizing conditioning requirements Understanding other environmental constraints Liquid and gaseous emissions Accurate and reliable laboratory and on-line compositional measurements Yield calculations and mass balance closure Process monitoring and control Mention other CSF are policy and political issuesMention other CSF are policy and political issues

29. Future Work Aligned with Program Targets2012 Target: Pilot scale demonstration of technology Produce pilot scale integrated performance data using the new pilot plant facility to demonstrate the 2012 cost target Focus on integration specific issues and 2012 targets along the way Test newly developed enzymes Understand effect of feedstock variability on process performance (with Feedstock Interface Task)

30. Future Work Aligned with Program TargetsBiomass Analytical Methods Develop rapid on-line methods for feedstocks and intermediate process streams Initial focus on pretreated stream Improve wet chemical analysis techniques for more accurate yield and mass balance calculations

31. Summary This project explores integrated process performance with a focus on achieving the 2012 Program goals for a pilot scale process demonstration Key 2012 Targets >90% xylan to xylose > 85% cellulose and non-glucose sugars to ethanol Validate in integrate pilot operation $1.31 ethanol cost target Provides practical knowledge of integrated system performance as well as identifying critical process issues and knowledge gaps Operation at process relevant conditions Recycle and emissions Develops state-of-the-art analytical tools to improve the accuracy and reliability of process measurements and yield calculations and techniques for on-line monitoring and process control

32. Summary (cont.) Recent Accomplishments Reduced/eliminated sugar losses during conditioning to 1-2% Achieved high ethanol concentration (~90 g/L) in glucose-supplemented hydrolysate liquor Demonstrated on-line measurement of corn stover composition Improved measurement of lignin in pretreated materials improving lignin mass balance closure from 165% to 124%

33. Summary (cont.) Future Work Integrated process performance Identify and address critical issues (e.g., waste water recycling ) and processing requirements on the way to achieving pilot scale performance targets Evaluate new enzymes Initiate new work in separation technology Investigate efficacy of membranes to improve process performance

34. Questions?

35. Feedback from Previous Project Reviews Interim Stage Gate Review Meeting held September 2004 Selected Feedback Develop on-line monitoring capability, especially for monitoring the enzymatic saccharification reactor and a second area for application of on-line monitoring would be in the fermentation reactor. Objective is in 2012 targets, this one due in FY08 Need to extend the variability studies to determine the impact of corn stover variability on pretreatability (sugar yields), enzymatic cellulose hydrolysis, and fermentability. Work being done this year Examining the gypsum question is low priority and should not be undertaken. No new work was undertaken Enzymatic saccharification time is too long and needs to be characterized with unwashed materials, that is, with background components (non-sugars) present during enzymatic saccharification. Work was performed in Pretreatment and Enzymatic Hydrolysis Task

36. 2012 Targets by R&D Area

37. 2012 Targets by R&D Area

38. Base Case Process Flow Diagram

39. Background on Process Calculations

40. Yield and Loss Calculations

41. Yield and Loss Calculations

42. Yield and Loss Calculations

43. Publications Schell, D.J. et al. �National Bioenergy Center Biochemical Platform Integration Project Quarterly Newsletter,� NREL, distributed quarterly. Bower, S., Wickramasinghe, R., Nagle, N.J. Schell, D.J. 2008. �Modeling sucrose hydrolysis in dilute sulfuric acid solutions at pretreatment conditions for lignocellulosic biomass,� Bioresource Technol. In Press. � Schell, D.J., Dowe, N., Ibsen, K.N., Riley, C.J., Ruth, M.F., Lumpkin, R.E. 2007. �Contaminant occurrence, identification and control in a pilot-scale corn fiber to ethanol conversion process,� Bioresource Technol. 98, 2942-2948. In Press. Zhang, P., Schell, D.J., McMillan, J.D. 2007. �Methodological analysis for determination of enzymatic digestibility of cellulosic materials,� Biotech. Bioeng. 96, 188-194. Chen, S. F.; Mowery, R. A.; Scarlata, C. J.; Chambliss, C. K. 2007. �Compositional Analysis of Water-Soluble Materials in Corn Stover,� J. Agric. Food Chem. 55, 5912-5918. Mohagheghi, A., Ruth, M., Schell, D.J. 2006. �Conditioning hemicellulose hydrolysates for fermentation: Effects of overliming pH on sugar and ethanol yields,� Process Biochemistry, 41, 1806-1811. Katzen, R., Schell, D.J. 2006. �Lignocellulosic Feedstock Biorefinery: History and Plant Development for Biomass Hydrolysis,� in Biorefineries � Industrial Processes and Production: Status Quo and Future Direction, Vol. 1, Eds. Kamm, B., Gurber, P., Kamm, M., Wiley-VCH Verlag GmbH & Co., Weinhein, Germany, 129-136.