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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
60%
63-
160%
Increase in
Population Energy demand
Source:
•CIA's The World Factbook
• World POPClock Projection, U.S. Census Bureau
• Energy Sources, 26:1119-1129,2004
World's Population
10
6.7
0
2
4
6
8
10
12
2008 2050
Year
Population
(billion)

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

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

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
crop residue
animal manure
forest residue
MSW, C&D
Category Millions of
dry tons/yr
U.S. (%)
Crop
residues
218.9 43
Animal
manures
35.1 7
Forest
residues
178.8 35
Landfill
wastes
78 15
%
(modified from
Perlack et al., 2005)

12. Ohio data
(modified from Jeanty
et al., 2004)
crop residue
animal manure
forest residue
MSW, C&D
Category Billions of
BTUs
Ohio (%)
Crop residues 53,717 18
Animal
manures
2,393 1
Forest residues 33,988 12
Landfill wastes 199,707 69
%

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. Wet biomass
(organic waste, manure)
Solid biomass
(wood, straw)
Sugar and starch plants
(sugar-cane, cereals)
Oil crops and algae
(sunflower, soybean)
Biomass
Biomass-to-Bioenergy Routes
Ethanol
Butanol
Methyl ester
(biodiesel)
Pyrolytic oil
Biogas
H2, CH4
Fuel gas
Sugar
Pure Oil
Conversion
processes
Electricity
Heat
Electrical
devices
Heating
Liquid
biofuels
Transport
Biofuels and Bioenergy Application
Anaerobic
fermentation
Gasification
Combustion
Pyrolysis
Hydrolysis
Hydrolysis
Extraction
Crushing
Refining
fermentation
Transesterification
Photosynthesis
6CO
2
+
6H
2
O
C
6
H
12
O
6
+
6O
2
co
2

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.  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
Glycerine
Methyl Ester
Triglyceride
Methoxide
Biodiesel from triglyceride oils

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

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

27. 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 Biomass Boiler
(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)
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.
PEM

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

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

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