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Lecture 25

Lecture 25. Chapter 17 Biomass: From Plants to Garbage. What is Biomass?. Energy derived from living matter Field crops Trees Water plants Municipal Solid Waste (MSW) Agricultural and Forestry waste. Biomass as a fuel. Solid fuels Wood chips Plant residue Liquid fuels

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Lecture 25

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  1. Lecture 25 Chapter 17 Biomass: From Plants to Garbage

  2. What is Biomass? Energy derived from living matter • Field crops • Trees • Water plants • Municipal Solid Waste (MSW) • Agricultural and Forestry waste

  3. Biomass as a fuel • Solid fuels • Wood chips • Plant residue • Liquid fuels • Solid conversion by chemical or biological action to ethanol or methanol • Gaseous fuels • Produced by high temperature and high pressure processes

  4. Biomass conversion is releasing stored energy from the sun • Photosynthesis CO2 + H2O + light energy  O2 + carbohydrates • Respiration • Reverse of Photosynthesis • Takes place in plants and animals • Plants use photosynthesis during the day and respiration at night • CO2 concentrations are highest in spring and lowest in fall at the end of growing season

  5. Facts you may have wondered about • 20% of 48 states is crop land • Largest crop is corn • Followed by soybeans and oats • 30% is commercial forest and woodlands • U.S. land base totals 2260 million acres • Could supply 1.3 billion dry tons of biomass/yr • Enough to supply 1/3 of our transportation needs

  6. Processes for conversion of biomass to other energy forms • Biochemical processes • Decomposition of organic waste in oxygen deficient environment (anaerobic bacteria) • Controlled fermentation for production of alcohols (ethanol and methanol) • Direct Combustion • Burn for fuel to produce space heating or steam power generation • Pyrolysis • Thermal decomposition of wastes into gas or liquid fuels

  7. History of Ethanol Ethanol made from grain mixed with gasoline was used with first cars

  8. History of Ethanol • Used for lamp fuel in late 1800’s • US and Germany used it to fuel vehicles during WWII • Limited use in 1950’s and 60’s due to cheap oil • 1970’s introduced ethanol again as “gasohol” during oil crisis • Recently, Flexible Fuel Vehicles (FFV) became available, E85 • 6+ million FFV’s on the road today (See NEVC)

  9. Add Steam Harvest Grind it Dissolve starch (long chains of glucose) FERMENTATION Add YEAST converts glucose to ethanol Add enzymes to break down starch to glucose. SACCHARIFICATION Distillation, collects ethanol Ethanol Production

  10. Ethanol Production 2 ways of making ethanol: • Dry mill • Wet mill

  11. Ethanol Production Wet mill Steep: breaks corn kernel down into its components

  12. Ethanol Production Glucose The key is breaking the cellulose and hemicellulose down into simpler sugars: glucose and sucrose Sucrose Cellulose, 6 carbon sugar, glucose Hemicellulose, 5 carbon sugars, xylose and arabinose Source: www.enzymes.co.uk/ Basics/cell_wall.gif (expired)

  13. Ethanol Production • This process can use anything that contains cellulose (wood, sugar cane, corn, paper, etc.) • All processes vary in economics and availability Sugar cane • Very economical because sugar is easily turned into ethanol • Not available – can only be grown in some states • A lot of labor needed to grow it

  14. Ethanol Production • Economics and availability • Wood, paper, certain grasses • Very abundant, can be grown in many places • Little work or fertilizer needed • Not efficient because not as much sugar available in the wood (more cellulose) • Corn is “in the middle” • Able to be grown in many states • Not that difficult or labor intensive to grow (compared to sugar cane) • Has more sugar immediately available than wood • This can be plotted in the following…

  15. Comparison of Economics and Availability ECONOMICAL Corn Starch Sugar Cane Corn Fiber Paper Switch Grass Wood Chips Stover Cottonwoods ABUNDANT & AVAILABLE

  16. Table 17-1, p. 552

  17. p. 552

  18. p. 553

  19. See Harold Bate http://www.green-trust.org/2000/biofuel/batesmethane.htm Fig. 17-4, p. 554

  20. p. 571

  21. 1 Hectare = 2.47 Acres Table 17-2, p. 556

  22. Fig. 17-5, p. 557

  23. Southern California Rapid Transit District p. 557

  24. Bio-Diesel • Three main ingredients • Alcohol • Vegetable oil (soy, palm, corn, canola, peanut, sunflower) • Catalyst • Alcohol • Methanol (made from natural gas) • Ethanol (just presented) Usually not used in large scale because of the amount needed and more catalyst needed

  25. Process of Making Bio-Diesel • Vegetable oil • The amount oil / acre varies • Palm – 4,585 lb oil / acre • Soybean – 345 lb oil / acre • Corn – 135 lb oil / acre • Animal fat can be used in place of oil but: • Need to process • Hard to process

  26. Process of Making Bio-Diesel • Catalyst • Used to speed up the reaction • Sodium hydroxide used with methanol • Potassium hydroxide used with ethanol • End products • Glycerin (ends up in bottom) • Bio-Diesel (on top) • Needs 8 hours for complete separation

  27. Bio-Diesel – Advantages • Any Diesel engine can run on bio-Diesel with little or no modifications • Reduces import of foreign oil • Cleaner emissions compared to regular Diesel • Diesel exhaust smell replaced with that of fried food!

  28. Yield per acre: Algae: 1800 gpa or more (est.- see soy figures and DOE quote below) Chinese tallow: 503 gpa - 970 gpa Palm oil: 508 gpa Coconut: 230 gpa Rapeseed: 102 gpa Soy: 59.2-98.6 gpa in Indiana (Soy is used in 80% of USA biodiesel) Peanut: 90 gpa Sunflower: 82 gpa http://en.wikipedia.org/wiki/Bio-diesel

  29. Bio-Diesel – Disadvantages • Results in a 5% decrease in torque, power, and fuel efficiency compared to regular Diesel fuel • Not all manufacturers will cover warranty of an engine that used bio-Diesel • Bio-Diesel gels more than regular Diesel • Anti-gel agents exist to counteract this • Bio-Diesel dissolves rubber parts (fuel lines, etc.) • Vehicles newer than 1993 have synthetic parts and are not affected • Viton good synthetic material replacement of rubber

  30. Municipal Solid Waste Fig. 17-6, p. 558

  31. p. 559

  32. Fig. 17-7, p. 562

  33. Table 17-3, p. 563

  34. Conventional Fireplace Fig. 17-9, p. 566

  35. Airtight Stove with Secondary Chamber Fig. 17-10, p. 567

  36. Table 17-4a, p. 569

  37. Table 17-4b, p. 569

  38. Table 17-5, p. 570

  39. 1 cord = 128 ft3 = 8' x 4' x 4' stack of wood Table 17-6, p. 575

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