Biomass & Biofuels Ethanol

1. Biomass & BiofuelsEthanol San Jose State University FX Rongère April 2009

2. Biochemical Conversion Thermochemical Conversion Extraction Anaerobic Digestion Fermentation Direct Combustion Gasification Pyrolysis Liquefaction Steam Gas Oil Charcoal Biogas Ethanol Bio-diesel Heat Electricity Transportation Biofuels • Biofuels cover a broad range of technologies and applications: Source: From Boyle, Renewable Energy, 2nd edition, 2004

3. Transportation fuels • The U.S. uses 130 billion gallons of gasoline and 41 billion gallons of diesel fuel per year made from oil of which 65% is imported • Transportation is the second source of CO2, about 2,000 MM tons per year in the USA Source: EPA, Inventory of U.S. Green House Gas Emissions and Sinks 1990-2006 April, 2008

4. U.S. Primary Energy Consumption by Source and Sector, 2007(Quadrillion Btu) Source: Energy Information Administration, http://www.eia.doe.gov/emeu/aer/pecss_diagram.html

5. Transportation • Passenger cars and light trucks count for 64% of transportation CO2 emissions Passenger car 22.9 MPG 12,000 Miles/y 5 tons/y CO2 Light Duty Truck 16.2 MPG 11,000 Miles/y 7 tons/y CO2 Source: S Davis, S Diegel Transportation Data Book Edition 26, ORNL-6978, 2007

6. Increase of consumption • Large Pickups and large SUV have pushed gasoline consumption since mid-90s. Source: S Davis, S Diegel Transportation Data Book Edition 26, ORNL-6978, 2007

7. Carbon emissions in Transportation Source: S Davis, S Diegel Transportation Data Book Edition 26, ORNL-6978, 2007

8. H O — H H H Ethanol • Molecule: C2H6O • Anhydrous Ethanol may be blended with Gasoline from 10% (E10) or be used pure (E100) H—C— C — H

9. Otto Cycle • It differs from Diesel cycle because the combustion is performed at constant volume Pressure PH    PL  Volume VL VH

10. Perfect compressor Energy Analysis • Adiabatic Compression Air is close to an ideal gas:

11. Energy Analyisis • Isentropic compression for a perfect gas like air and

12. Energy Analysis • Compression phase: • Expansion phase:

13. Energy Analysis • Combustion phase:

14. Energy Analysis • Conversion rate: and then

15. Compression Ratio • Auto-ignition point: • Gasoline: 280oC • Ethanol: 425oC • Compression Ratio Ethanol Gasoline Nota: Actual cycles are not isentropic and reach lower temperature for the same compression ratio

16. Efficiency • Higher compression ratio of Ethanol allows higher conversion rate Octane index of Ethanol is 113 Ethanol Gasoline

17. Advantages • Bio-degradable • Better Performance by increase of the compression ratio • May be blended with gasoline, the most used fuel • Broad feed stock

18. Disadvantages • Lower Energy density than gasoline • Fuels with more than 10% ethanol are not compatible with non E85-ready fuel car because of corrosion • Distillation requires a lot of energy

19. Ethanol is booming Gasoline consumption in the USA: 130 bGallons/year

20. Ethanol plants (2007)

21. Ethanol plants (2007)

22. In other countries • USA is the worldwide leader for bio-ethanol production followed by Brazil with 4.5 MM Gal/y in 2006 Cenex gas station on 320 Street Northwest in Bemidji, Minnesota

23. Step 1: Cracking of large polymer molecules to generate simple sugar: Glucose Requires Energy Step 2: Fermentation of the sugar with yeast to generate alcohol about 10% C6H12O6 + yeast → 2 C2H6O + 2 CO2 Exothermic but must stay at 30 -37oC Step 3: Distillation to raise the alcohol concentration to 95-96% limited by azeotropic ditillation Requires a lot of energy of water evaporation Production Process

24. Azeotropic distillation • Azeotrope is a mixture of two or more pure compounds which does not change with the temperature

25. Sub-product valorization: The residues are recycled as cattle food It requires energy for concentration Production Process Step 4: Dehydration Using Molecular sieves

26. Production Process

27. Dried Distillers Grains (DDGS) • Dried Distillers Grains are used as a food complement for animals • 1 bushel of corn produces 17 pounds of DDGS • Up to 40% of ruminant food may be DDGS Source: Renewable Fuel Association Ethanol Industry Outlook 2007

28. Corn Products Cost % of Energy in Corn Energy Consumption for bioethanol Production • The balance for Ethanol generation is barely higher than 1: = 66,000 MM BTU 1 acre 140 bushels of corn 370 Gallons of EtOH 31,000 MM BTU Today, ethanol production (6,500 MM Gallons) represents 17 MM acres of Corn Source: John Duxbury Update on the Biofuel Debate: Energetics, GHG Emissions, Strategy Crop and Soil Sciences Cornell University

29. Energy Consumption for bioethanol Production Source: Niclas Scott Bentsen Claus Felby Karen Hvid Ipsen 2006. ENERGY BALANCE OF 2nd GENERATION BIOETHANOL PRODUCTION IN DENMARK

30. Energy Consumption for bioethanol Production • Total Processing Energy 39,000 to 50,000 BTU/gal Bioethanol energy: 84,000 BTU/gal Distillation energy: 22,500 BTU/Gal 7,900 kJ/kg Pierre Côté, Christian Roy, Normand BernierVaperma Inc.Mark Schwartz, Ted Dodkin, Chris BradtGreenfield Ethanol, Inc. Dewatering Field Demonstration of the SiftekTMMembrane for Ethanol International Fuel ethanol Workshops, June 2007

31. Distillation

32. Distillation Curve Vapor    Liquid 

33. Energy Budget • Vaporization Heat First Stage: Ethanol: 61% Ethanol: 10%

34. Better solutions • Mechanical Vapor Recompression (MVR) • Membranes Pierre Côté, Christian Roy, Normand BernierVaperma Inc.Mark Schwartz, Ted Dodkin, Chris BradtGreenfield Ethanol, Inc. Dewatering Field Demonstration of the SiftekTMMembrane for Ethanol International Fuel ethanol Workshops, June 2007

35. How it works? • The vapor is compressed to raise its condensation temperature    

36. How it works?    

37. How it works    

38. How it works?

39. How it works? 1,000 lb/h = 0.216 kg/s = 1/7.9 kg/s

40. Energy in Ethanol USA Brazil Energy Balance for EtOH USA & Brazil • Associative N fixation in cane reduces N input • Cane has 4 ratoon crops reducing planting cost • Bagasse is used to generate energy for cane conversion to ethanol O:I 1.16 8.02 Source: John Duxbury Update on the Biofuel Debate: Energetics, GHG Emissions, Strategy Crop and Soil Sciences Cornell University

41. Ethanol Plants Ethanol plant in West Burlington, Iowa Ethanol plant in Sertãozinho, Brazil. Ethanol plant in Macon, Missouri

42. Ethanol Crop Sweet Sorghum Corn Sugar cane Switch Grass Poplar Miscanthus

43. Corn price is driven by the market • Tripled from 2005 to 2008, halved since July 2008 Source: www.futures.tradingcharts.com

44. Ethanol Price (2008) Source: http://tonto.eia.doe.gov/oog/info/gdu/gasdiesel.asp US $ per Gallon Gasoline Equivalent $ 1.1 $ 2.2 $ 3.2 $ 4.2 $ 5.3 Wholesale price: $2.60 Source: John Duxbury Update on the Biofuel Debate: Energetics, GHG Emissions, Strategy Crop and Soil Sciences Cornell University Feb. 7, 2007

45. Ethanol Price (2009) Source: http://tonto.eia.doe.gov/oog/info/gdu/gasdiesel.asp US $ per Gallon Gasoline Equivalent $ 1.1 $ 2.2 $ 3.2 $ 4.2 $ 5.3 Wholesale price: $1.23 Source: John Duxbury Update on the Biofuel Debate: Energetics, GHG Emissions, Strategy Crop and Soil Sciences Cornell University Feb. 7, 2007

46. Ethanol to replace MTBE • MTBE is currently used to increase Octane index of gasoline and improve combustion • MTBE is a pollutant of water • Ethanol can replace MTBE in gasoline in the USA: 5.8% of Ethanol in gasoline i.e: 8,000 MM Gal/y Molecule of MTBE: C5H12O

47. Summary BioFuels