Let

1
Lets envision an ideal biofuel process
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Feedstock
CO2
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Biomass

• Biomass
• Plants
• Animals (by way of plants)
• Plants
• Use solar energy to convert water and CO2 to
  sugars through the process of photosynthesis
• Harvested portions of live plants or remains are
  sources of biomass
• Animals
• Consume plants (or consumers of plants)
• Elimination products or remains are sources of
  biomass
• Virtually all of our current energy supply is
  derived from biomass (fossil fuels are just
  well-aged)

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Multiple Feedstocks

• municipal solid waste
• sewage sludge
• animal manure

• trees
• grass
• agricultural residues
• energy crops

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U.S. Biodegradable Wastes
Amount
Alcohol Potential
Waste
(million tonne/year)
(billion gal/year)
78
Municipal Solid Waste
10
Sewage Sludge
10.9
3
Industrial Biosludge
4.3
Recycled Paper Fines
400
Agricultural Residues
52
330
Forestry Residues
43
220
Manure
28
Total
1,046
135
U.S. Gasoline Consumption 130 billion
gal/year U.S. Diesel Consumption 40 billion
gal/year
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How to Get Liquid Transportation Fuels from
Biomass

• Convert sugars and starches to ethanol
  fermentation
• Convert plant oils to biodiesel
  transesterification
• Convert anything to liquid pyrolysis
• Convert anything to gas (gasification) with
  subsequent conversion to liquid aka biomass to
  liquids (BTL)

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The Challenge
Can we achieve sufficiently high yields of
targeted chemical compounds from solubilized
biomass fractions to justify the cost of biomass
pretreatment?
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Biofuels, in Order of Maturity, p1 of 2
FUEL SOURCE BENEFITS STATUS
Grain/Sugar Ethanol Corn, sorghum, sugarcane High-octaneWidely available sources Commercially proven
Biodiesel Vegetable and seed oils fats and greases Increased fuel lubricity Widely available sources Commercially proven
Gasoline and diesel blends Ethanol or biodiesel blended with petroleum fuels Relatively straightforward for refineries to processDecreased sulfur emissions over standard fuels Commercial trials in progress
Cellulosic Ethanol Grasses, wood chips, and agricultural residues High-octaneLess demand on agricultural lands than grain ethanol DOE program targeting 2012 demonstration
Butanol Corn, sorghum, wheat, sugarcane Low-volatilityHigh energy-densityWater tolerant BP and DuPont in progress
Adopted from NREL (2006) http//www.nrel.gov/bioma
ss/pdfs/39436.pdf
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Biofuels, in Order of Maturity, p2 of 2
FUEL SOURCE BENEFITS STATUS
Pyrolysis Liquids Lignocellulosic biomass Can utilize waste products Potential source of aromatics and phenols Several commercial facilities produce energy and chemicals
Syngas Liquids Various biomasses Can utilize waste productsCan be integrated with fossil fuel sources (e.g., coal)High quality fuel Commercially demonstrated a large scale using fossil fuels biomass projects underway
Biodiesel or jet fuel Microalgae High yield per acreCould be integrated with CO2 capture and reuse Demonstrated at pilot scale in 1990s. Many start-ups currently underway
Hydrocarbons(designer fuels) Biomass carbohydrates Generate synthetic copies of current petroleum derived feedstocks Laboratory-scale research
Adopted from NREL (2006) http//www.nrel.gov/bioma
ss/pdfs/39436.pdf
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Ethanol (EtOH)

• Chemical Composition
• CH3CH2OH or (C2H6O)
• Ethanol is ethanol source independent
• Also known as ethyl alcohol or grain alcohol
• 2 types
• Biologic conversion of starches to sugar
  followed by fermentation of sugar with yeast
• Synthetic acid catalyzed hydration of ethylene
• Blending
• Currently used as a additive (10 max) to improve
  performance (octane) of gasoline
• Internal combustion engines must be designed to
  accommodate ethanol content gt10

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Ethanol Sources

• Most common sources are plants with high sugar or
  starch content (e.g., corn, beets, cane,
  potatoes)
• Sources with more complex cellular structures
  (e.g., wood, grass, stalks) require more effort
  to extract available sugars (cellulosic ethanol)

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Biodiesel or FAME (Fatty Acid Methyl Ester)

• Chemical composition
• Similar to petroleum diesel fuel in structure
  (straight chain) and number of carbon atoms (10
  to 20)
• Differs in that it is oxygenated and has a small
  number of double bonds
• Fuel characteristics will vary slightly depending
  upon source
• Blending
• Completely miscible with diesel fuel
• Used as an additive (5 max) to increase cetane
  and improve performance of diesel
• Internal combustion engines must be designed to
  accommodate fuels with FAME content gt5

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Biodiesel Sources

• Plant oils
• Soybean
• Palm
• Rice
• Cottonseed
• Rapeseed (canola)
• Waste oils (plant and animal)
• Algae recent interest because
• High amounts of oil
• Minimal competition with food crops and crop land
• Can be grown on land with low potential for CO2
  sequestration (e.g. deserts)
• Does not necessarily require fresh water

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Biomass to Liquids (BTL)via Gasification

• Solid or solid/liquid biomass is converted to gas
  at high temperatures in the presence of small
  amounts of oxygen
• Main objective is to transfer the maximum amount
  of chemical energy within the feedstock to the
  gaseous fraction by producing a high yield of low
  molecular weight products (high HC)
• The resulting gas is conditioned to produce
  synthesis gas (syngas)
• Syngas is then converted to liquid fuel via the
  Fischer-Tropsch process

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High-Productivity Feedstocks
30
Productivity Dry tons/(acreyr)
20
3.4
Corn grain Sweet sorghum
Energy cane
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Sweet Sorghum
Grows in 35 US states
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Energy Cane
18
Energy Cane
19
High Agricultural Income
1090
Gross Income /(acreyr)
730
340
Corn grain Sweet sorghum
Energy cane (2.40/bu)
(40/tonne) (40/tonne)
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Low Environmental Impact
Environmental cost per unit of biomass
Corn Sweet Energy Grain
Sorghum Cane
High Low Low High
Low Low High
Low Low High Low
Low High Low
Low
Water Fertilizer Pesticides Herbicides Soil
erosion
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Ideal Process Properties
No sterility No genetically modified organisms
(GMOs) Adaptable No pure cultures Low capital No
enzymes High product yields No vitamin addition
Co-products not required
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Fuel Properties
Ethanol MTBE Mixed
Alcohols
Octane high
high high Volatility
high low
low Pipeline shipping no
yes yes Energy content
low high
high Heat of vaporization high
low low Ground water damage
no yes no
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MixAlco Process
Mixed Alcohol Fuels
Carboxylate Salts
Mixed Ketones
Thermal Conversion
Ferment
Pretreat
Dewater
Biomass
Hydrogenate
Lime
Hydrogen
Calcium Carbonate
Lime Kiln
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Storage Pretreatment Fermentation
Tarp Cover
Air
Biomass Lime Calcium Carbonate
Gravel
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Dewatering
Mixed Alcohol Fuels
Carboxylate Salts
Mixed Ketones
Thermal Conversion
Ferment
Pretreat
Dewater
Biomass
Hydrogenate
Lime
Hydrogen
Calcium Carbonate
Lime Kiln
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Vapor-Compression Dewatering
Compressor
Work
Salt Solution (Fermentor Broth)
Distilled Water
Filter
Salt Crystals
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Effect of Feedstock Cost (800 tonne/h, 15 ROI)
1.00 0.80 0.60 0.40 0.20 0.00
Alcohol Selling Price (/gal)
-40 -20 0
20 40
Biomass Cost (/tonne)
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Centralized Processing
15.3 mi
50 of area planted
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How do we increase engine efficiency?

• Electric hybrids (2 X)
• Better engines (2 4 X)

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Meeting US gasoline needs by growing energy cane
in Brazil
1
2
3
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Meeting US gasoline needs by growing sweet
sorghum in United States
1
2
3
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Conclusion

• Reduce wastes
• Cleaner air
• New agricultural markets
• Energy security
• Improve balance of payments
• Address global warming
• Address energy shortage
• More flexible international relations
• Benefit developing nations