Development of Cellulosic Biofuels

Transcription

1 Development of Cellulosic Biofuels Chris Somerville Energy Biosciences Institute UC Berkeley, LBL, University of Illinois Current and predicted energy use Current use 13 TW Global Primary Energy Supply by Fuel*: % 2% 4% 5% 2% 6% 39% 37% 23% 27% 25% Key: 23% -oil - coal -gas - nuclear -hydro - modern renewables * - excludes traditional biomass Source: IEA 2004 & Jim Breson 1

2 Combustion of biomass can provide carbon neutral energy Sunlight CO 2 Photosynthesis Combustion Polysaccharides (Storage) Work Combustion of biomass can provide carbon neutral energy Sunlight CO 2 Tilling Land conversion Fertilizer Transportation ti Processing CO 2 Photosynthesis Combustion Biomass Work But it depends on how the biomass is produced and processed 2

3 GHG and runoff monitoring Effect of land use change on soil carbon Guo & Gifford, Global Change Biology 8,345 Responsible Biofuels No conversion of undeveloped land No erosion, runoff, nitrous oxide emissions Net GHG benefits based on full lifecycle accounting No effect on food production 3

4 Remote land use and meteorological monitoring >>A billion acres of agricultural land have been abandoned Campbell et al., Env. Sci. Technol. (2008) 42,5791 US Biomass inventory = 1.3 billion tons 26 B gals ~ Corn stover 19.9% 9% Wheat straw 6.1% Soy 6.2% Crop residues 7.6% Grains 5.2% Perennial crops 35.2% Forest 12.8% Manure 4.1% Urban waste 2.9% From: Billion ton Vision, DOE & USDA

5 Crop growth measurement by tower and remote helicopter, IR for stress An energy crop Yield of 26.5 tons/acre observed by Young & colleagues in Illinois, without irrigation Steve Long et al Courtesy of S Switchgrass and Miscanthus at Illinois Mg/Ha mean Heaton, Dohleman and Long, Climate Change Biology

6 Storage temperature monitoring Harvesting Miscanthus GPS mineral nutrient monitoring Response of Miscanthus to nitrogen fertilizer N0 N60 N120 Yield (t/ha) Year Christian, Riche & Yates Ind. Crops Prod. (2008) 6

7 Annual precipitation Mixed Alcohols i-c 4 NH 3 Summary of Syngas-Liquids Processes Alkali-doped ZnO/Cr 2O 3 Cu/ZnO; Cu/ZnO/Al 2O 3 CuO/CoO/Al 2O 3 MoS 2 Isosynthesis ThO 2 or ZrO 2 N 2 over Fe/FeO Waxes Diesel Olefins Gasoline Fischer-Tropsch H 2 O WGS Purify (K 2 O, Al 2 O 3, CaO) Fe, Co, Ru Syngas CO + H 2 H 2 HCo(CO) 4 HCo(CO) 3 P(Bu 3 ) Rh(CO)(PPh 3 ) 3 Oxosynthesis Formaldehyde Co, Rh Ag Cu/ZnO Co homologation Ethanol Aldehydes Alcohols MTBE ange isobutylene acidic ion excha Methanol Al 2 O 3 DME Direct Use Acetic Acid carbonylation CH 3 OH + CO Co, Rh, Ni zeolites MTO MTG M100 M85 DMFC Richard Bain, NREL Olefins Gasoline 7

8 Steps in cellulosic ethanol production From: Breaking the Biological Barriers to Cellulosic Ethanol Dilute acid schematics 1-6 Aden et al (2002) NREL/TP Feed handling Prehydrolysis Solid-liquid separation Lime addition Seed production Saccharification and fermentation 8

9 Dilute acid schematics 7-12 Aden et al (2002) NREL/TP Beer distillation Rectification distillation Ethanol dehydration Evaporation Lignin separation and recycle Anaerobic digestion Dilute acid schematics Aden et al (2002) NREL/TP Aerobic digestion Storage Boiler feed drying Combustion and turbogenerator Boiler feed water preparation Boiler feed water adjuvants 9

10 Dilute acid schematics Aden et al (2002) NREL/TP Cooling water Process water Sterile water Many Sensors Batch vs continuous fermentation with pervaporation (50 Mgal/y) 16 x 250,000 gal 1 x 330,000 gal Membrane properties 42 wt% ethanol 0.15 kg/m 2 /h $200/m 2 O Brien et al J Membrane Sci 166,105 10

11 Plants are mostly composed of sugars 3 nm Section of a pine board Polymerized glucose Structure of cellulose Nishiyama et al JACS 125(47)14300 Lehtio et al PNAS 100,484 11

12 Lignin occludes polysaccharides Cellulose Lignin Hemicellulose Enzymatic hydrolysis of cellulose is slow Skopec, Himmel, Matthews, Brady Protein Engineering 16,

13 Cellulase hydrolyzing cellulose cellulose NREL Accessory proteins stimulate activity of cellulases and chitinases Eijsink et al, Trends Biotechnol 26,228 13

14 Some cellulytic enzymes are components of a molecular machine From: Breaking the Biological Barriers to Cellulosic Ethanol Possible routes to improved catalysts Explore the enzyme systems used by termites (and ruminants) for digesting lignocellulosic material Compost heaps and forest floors are poorly explored In vitro protein engineering of promising enzymes Develop synthetic organic catalysts (for polysaccharides and lignin) 14

15 Comparison of carbohydrate-active enzymes in Postia placenta vs other fungi Family 1 carbohydrate binding modules P. placenta T reesei P. chrysosporium endo-glycanases endo-xylanase exocellobiohydrolases cellulose binding endoglucanases Martinez et al PNAS 106,1954 Dissolution of cellulose in an ionic liquid (novel pretreatment methods may create fundamental changes) Untreated Treated Swatloski, Spear, Holbrey, Rogers J. Am. Chem. Soc., 124 (18), ,

16 Saccharification & Fermentation Fermentation Yield Cost Impact ol Selling Price ($/gal) $2.40 $2.10 $ % 92% Minimum Ethan NREL $1.50 $ % $1.33 $1.28 $1.23 glucose only add 85% xylose add 85% arabinose all other sugars 85% Fermentation of all sugars is essential cellulose Hemi cellulose Lignin Typical grass composition Jeffries & Shi Adv Bioch Eng 65,118 16

17 Engineered yeast 424A(LNH-ST) utilizes xylose Sedak and Ho, Appl Biochem Biotechnol :403-16, 2004 Routes to potential fuels Fortman et al, Trends Biotechnology 26,375 17

18 Steps in cellulosic ethanol production From: Breaking the Biological Barriers to Cellulosic Ethanol Biomass before and after treatment Before 168 h enzymatic hydrolysis, 64% d Zheng et al (2006) Biotechnology & Bioengineering 97,265 18

19 Cellulose to intermediates Binder and Raines JACS 2009 Conversion of sugar to alkanes Huber et al., (2005) Science 308,

20 The hydrogen economy Justin Adams, BP The Future? 20

21 Linocellulose to ethanol process Conc. H 2SO 4 Decrystallization Hydrolysis Water Hydrolysis Lignin Utilization Biomass Acid Reconcentration Acid/Sugar Separation Gypsum Ethanol dehydration Water Neutralization Tank Ethanol recovery Purified Sugar Solution Fermentor 21