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Bioenergy from Agricultural Wastes

Bioenergy from Agricultural Wastes. Ann D. Christy, Ph.D., P.E. Associate Professor Dept of Food, Agricultural, and Biological Engineering USAIN April 2008. World Energy Prospects. Increase in Population Energy demand. Source: CIA's The World Factbook

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Bioenergy from Agricultural Wastes

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  1. Bioenergy from Agricultural Wastes Ann D. Christy, Ph.D., P.E. Associate Professor Dept of Food, Agricultural, and Biological Engineering USAIN April 2008

  2. World Energy Prospects Increase in PopulationEnergy demand • Source: • CIA's The World Factbook • World POPClock Projection, U.S. Census Bureau • Energy Sources, 26:1119-1129,2004

  3. Other concerns • Pollution • Climate change • Resource depletion

  4. Renewable energy sources Summary of energy resources consumption in United States, 2004 • By 2030, bio-energy, 15-20% energy consumption Source: USDA-DOE, 2005, http://www.eere.energy.gov/biomass/publications.html.

  5. Overview • Bioenergy history • Ag wastes and other biomass • Biomass to Bioenergy • Conversion processes • Pros & Cons • Applications • Biofuels • Bioheat • Bioelectricity

  6. Some U.S. bioenergy history • 1850s: Ethanol used for lighting (http://www.eia.doe.gov/ kids/energyfacts/sources/renewable/ethanol.html#motorfuel) • 1860s-1906: Ethanol tax enacted (making it no longer competitive with kerosene for lights) • 1896: 1st ethanol-fueled automobile, the Ford Quadricycle (http://www.nesea.org/greencarclub/factsheets_ethanol.pdf) Bioenergy is not new!

  7. More bioenergy history • 1908: 1st flex-fuel car, the Ford Model T • 1919-1933: Prohibition banned ethanol unless mixed with petroleum • WWI and WWII: Ethanol used due to high oil costs • Early 1960s: Acetone-Butanol-Ethanol industrial fermentation discontinued in US • Today, about 110 new U.S. ethanol refineries in operation and 75 more planned (photo from http://www.modelt.org/gallery/picz.asp?iPic=129)

  8. Ag wastes and other biomass • Waste Biomass • Crop and forestry residues, animal manure, food processing waste, yard waste, municipal and C&D solid wastes, sewage, industrial waste • New Biomass: (Terrestrial & Aquatic) • Solar energy and CO2 converted via photosynthesis to organic compounds • Conventionally harvested for food, feed, fiber, & construction materials

  9. Agricultural and Forestry Wastes • Crop residues • Animal manures • Food / feed processing residues • Logging residues (harvesting and clearing) • Wood processing mill residues • Paper & pulping waste slurries

  10. Municipal garbage & other landfilled wastes • Municipal Solid Waste • Landfill gas-to-energy • Pre- and post-consumer residues • Urban wood residues • Construction & Demolition wastes • Tree trimmings • Yard waste • Packaging • Discarded furniture

  11. % U.S. Data (modified from Perlack et al., 2005)

  12. % Ohio data(modified from Jeanty et al., 2004)

  13. Biomass to Bioenergy • Biomass: renewable energy sources coming from biological material such as plants, animals, microorganisms and municipal wastes

  14. Bioenergy Types • Biofuels • Liquids • Methanol, Ethanol, Butanol, Biodiesel • Gases • Methane, Hydrogen • Bioheat • Wood burning • Bioelectricity • Combustion in Boiler to Turbine • Microbial Fuel Cells (MFCs)

  15. Conversion Processes • Biological conversion • Fermentation (methanol, ethanol, butanol) • Anaerobic digestion (methane) • Anaerobic respiration (bio-battery) • Chemical conversion • Transesterification (biodiesel) • Thermal conversion • Combustion • Gasification • Pyrolysis

  16. 6CO2 + 6H2O C6H12O6 + 6O2 Biomass-to-Bioenergy Routes Conversion processes Photosynthesis Biomass Biofuels and Bioenergy Application Anaerobic fermentation Heat Heating Wet biomass (organic waste, manure) Biogas H2, CH4 Gasification Combustion Pyrolysis Hydrolysis Fuel gas Electricity Solid biomass (wood, straw) Electrical devices Pyrolytic oil Hydrolysis Extraction co2 Ethanol Butanol Sugar and starch plants (sugar-cane, cereals) Sugar fermentation Transport Liquid biofuels Crushing Refining Oil crops and algae (sunflower, soybean) Methyl ester (biodiesel) Pure Oil Transesterification

  17. Advantages of Biomass • Widespread availability in many parts of the world • Contribution to the security of energy supplies • Generally low fuel cost compared with fossil fuels • Biomass as a resource can be stored in large amounts, and bioenergy produced on demand • Creation of stable jobs, especially in rural areas • Developing technologies and knowledge base offers opportunities for technology exports • Carbon dioxide mitigation and other emission reductions (SOx, etc.)

  18. Environmental Benefits

  19. Drawbacks of Biomass • Generally low energy content • Competition for the resource with food, feed, and material applications like particle board or paper • Generally higher investment costs for conversion into final energy in comparison with fossil alternatives

  20. Applications

  21. Biofuel Applications: Liquids • Ethanol and Butanol: can be used in gasoline engines either at low blends (up to 10%), in high blends in Flexible Fuel Vehicles or in pure form in adapted engines • Biodiesel: can be used, both blended with fossil diesel and in pure form. Its acceptance by car manufacturers is growing

  22. Process for cellulosic bioethanol • http://www1.eere.energy.gov/biomass/abcs_biofuels.html

  23. Why Butanol? • More similar to gasoline than ethanol • Butanol can: • Be transported via existing pipelines (ethanol cannot) • Fuel engines designed for use with gasoline without modification (ethanol cannot) • Produced from biomass (biobutanol) as well as petroleum (petrobutanol) • Toxicity issues (no worse than gasoline)

  24. Biodiesel from triglyceride oils • Triglyceride consists of glycerol backbone + 3 fatty acid tails • The OH- from the NaOH (or KOH) catalyst facilitates the breaking of the bonds between fatty acids and glycerol • Methanol then binds to the free end of the fatty acid to produce a methyl ester (aka biodiesel) • Multi-step reaction mechanism: Triglyceride→Diglyceride →Monoglyceride →Methyl esters+ glycerine Methoxide Methyl Ester Triglyceride Glycerine

  25. Methanol Raw Oil Catalyst NaOH Crude Biodiesel (methyl ester) Crude glycerin Excess methanol Catalyst KOH Acid (phosphoric) Transesterification Reaction Catalyst Mixing Neutralization Methanol Recovery Recovered methanol Biodiesel, glycerin Phase Separation gravity or centrifuge Crude Glycerine Biodiesel, impurities Purification (washing) Wash water water Fertilizer K3PO3 Fuel Grade Biodiesel Biodiesel Production

  26. Biofuel Applications: Gases • Hydrogen: can be used in fuel cells for generating electricity • Methane: can be combusted directly or converted to ethanol

  27. Biomass Boiler Bioheat Applications • Small-scale heating systems for households typically use firewood or pellets • Medium-scale users typically burn wood chips in grate boilers • Large-scale boilers are able to burn a larger variety of fuels, including wood waste and refuse-derived fuel (for more info: Dr. Harold M. Keener, OSU Wooster, E-mail  keener.3@osu.edu)

  28. Bioelectricity Applications • Co-generation: Combustion followed by a water vapor cycle driven turbine engine is the main technology at present • Microbial Fuel Cells (MFCs): Direct conversion of biomass to electricity

  29. Microbial fuel cells (MFCs) PEM Electrons flow from an anode through a resistor to a cathode where electron acceptors are reduced. Protons flow across a proton exchange membrane (PEM) to complete the circuit.

  30. Bio-electro-chemical devices • Bacteria as biocatalysts convert the biomass “fuel” directly to electricity • Oxidation-Reduction reaction switches from normal electron acceptor (e.g., O2, nitrate, sulfate) to a solid electron acceptor: Graphite anode It’s all about REDOX CHEMISTRY!

  31. Membrane Cathode Anode • Two-compartment MFC • Proton exchange membrane: • Nafion 117 or Ultrex • Electrodes: Graphite plate • 84 cm2 • Working volume: 400 ml Microbial fuel cells in the lab ANODE CATHODE

  32. Cathode Anode Bacteria Cell Wall Proton Exchange Membrane H+ e- H+ e- Anode compartment Cathode compartment Bacteria Cell Not to Scale 6CO2 + 24e- + 24H+ e- e- 2CO2 + 8e- + 8H+ Cellulose Acetate n=1 e- Glucose e- β-Glucan (n≤7) β-Glucan (n ≤7) H+ O2 H+ n≥2 Propionate Cellodextrin 3CO2 + 28e- + 28H+ H2O β- Glucan (n-1) Butyrate 4CO2 + 18e- + 18H+

  33. My own MFC story • Undergraduate in-class presentation, 2003 • Bond, D.R. Holmes, D.E., Tender L.M., Lovley D.R. 2002. Electrode-reducing microorganisms that harvest energy from marine sediments. Science 295: 483–485. • Extra-curricular student team project, 2004-2005 • USEPA - P3 first round winner 2005 • #1 in ASABE’s Gunlogson National Competition 2005 • Research program, 2005 to present • 3 Ph.D. students, 2 undergrad honors theses, 4 faculty • Over $200,000 in grant funding • High school science class project online resource http://digitalunion.osu.edu/r2/summer07/nskrinak/index.html

  34. References • Ezeji, T., N. Qureshi, H.P. Blaschek. 2007. Butanol production from agricultural residues: Impact of degradation products on Clostridum beijerinckii growth and butanol fermentation. Biotechnol. Bioeng. 97, 1460-1469. • Jeanty, P.W., D. Warren, and F. Hitzhusen. 2004. Assessing Ohio’s biomass resources for energy potential using GIS. OSU Dept of Ag, Env., and Development Economics, for Ohio Dept of Development. http://www.puc.state.oh.us/emplibrary/files/media/biomass/bioenergyresourceassessment.pdf • Klass, Donald L. 1998. Biomass for Renewable Energy, Fuels, and Chemicals. Academic Press. ISBN: 9780124109506. • Perlack et al. 2005. Biomass as feedstock for a bioenergy and bioproducts industry: The technical feasibility of a billion-ton annual supply. USDOE-USDA. http://www.puc.state.oh.us/emplibrary/files/media/biomass/BiomassFeedstock.pdf • Rabaey, K., Verstraete, W. 2005. Microbial fuel cells: Novel biotechnology for energy generation. Trends. Biotechnol. 23:291-298. • Rismani-Yazdi, H., Christy, A. D., Dehority, B.A., Morrison, M., Yu, Z. and Tuovinen, O. H. 2007. Electricity generation from cellulose by rumen microorganisms in microbial fuel cells. Biotechnol. Bioeng. 97, 1398-1407. • Skrinak, N. 2007. OSU Microbial Fuel Cell Learning Center <http://digitalunion.osu.edu/r2/summer07/nskrinak/index.html> • USDOE Biomass Program. ABCs of Biofuels <http://www1.eere.energy.gov/biomass/abcs_biofuels.html>. Accessed April 2008.

  35. For more info (or to request reference list) Ann D. Christy, Ph.D., P.E. Associate Professor Dept of Food, Agricultural, and Biological Engineering 614-292-3171 Email: christy.14@osu.edu

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