let’s envision an ideal biofuel process. feedstock co 2
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Let’s envision an ideal biofuel process
Let’s envision an ideal biofuel process
FeedstockFeedstock
CO2
BiomassBiomass 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”)
Multiple FeedstocksMultiple Feedstocks
• treestrees• grassgrass• agricultural residuesagricultural residues• energy cropsenergy crops
• municipal solid wastemunicipal solid waste
• sewage sludgesewage sludge
• animal manureanimal manure
7878
10.910.9334.34.3
400400
330330220220
U.S. Biodegradable Wastes
Municipal Solid WasteMunicipal Solid WasteSewage SludgeSewage SludgeIndustrial BiosludgeIndustrial BiosludgeRecycled Paper FinesRecycled Paper Fines
Agricultural ResiduesAgricultural Residues
Forestry ResiduesForestry Residues
ManureManure
AmountAmount(million tonne/year)(million tonne/year)
Alcohol PotentialAlcohol PotentialWasteWaste (billion gal/year)
10101.41.4
0.40.40.50.5
5252
43432828
TotalTotal 1,0461,046 135135U.S. Gasoline Consumption = 130 billion gal/yearU.S. Gasoline Consumption = 130 billion gal/yearU.S. Diesel Consumption = 40 billion gal/yearU.S. Diesel Consumption = 40 billion gal/year
How to Get Liquid Transportation Fuels from BiomassHow 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)
The Challenge
Jet Fuel
forestforestwastewaste
corncornstoverstover
switch-switch-grassgrass
Gasification to “syngas” (CO + H2)
Diesel
Gasoline
LignocelluloseLignocellulose
Fisher-Tropsch
methanol
Gasolinecorncorngraingrain
sugarcanesugarcane
starchSaccharification lignin burn
Enzymatic Fermentation Ethanol
Pyrolysis, fast or slowgases
bio-oil
sugar
Sugar/starchSugar/starch
Liquid Phase Processing
Dissolution
Can we achieve sufficiently high yields of targeted chemical compounds from solubilized biomass fractions to justify the cost of biomass pretreatment?
Biofuels, in Order of Maturity, p1 of 2Biofuels, in Order of Maturity, p1 of 2
Adopted from NREL (2006) http://www.nrel.gov/biomass/pdfs/39436.pdf
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
Biofuels, in Order of Maturity, p2 of 2Biofuels, 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/biomass/pdfs/39436.pdf
Ethanol (EtOH)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 >10%
OH
Ethanol SourcesEthanol 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)
Biodiesel or FAME (Fatty Acid Methyl Ester)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 >5%
Biodiesel SourcesBiodiesel 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
Biomass to Liquids (BTL)via GasificationBiomass 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 H:C)
The resulting gas is “conditioned” to produce synthesis gas (syngas)
Syngas is then converted to liquid fuel via the Fischer-Tropsch process
High-Productivity FeedstocksHigh-Productivity Feedstocks
Corn grain Sweet sorghum Energy cane
3.4
20
30
Pro
duct
ivit
y
Dry
tons
/(ac
re·y
r)
Sweet SorghumSweet Sorghum
Grows in ~35 US states
Energy Cane
Energy Cane
High Agricultural IncomeHigh Agricultural Income
Corn grain Sweet sorghum Energy cane ($2.40/bu) ($40/tonne) ($40/tonne)
340
730
1090
Gro
ss I
ncom
e
$/(a
cre·
yr)
Low Environmental ImpactLow Environmental Impact
WaterFertilizerPesticidesHerbicidesSoil erosion
Corn Sweet EnergyGrain Sorghum Cane
High Low Low High Low Low High Low Low High Low Low High Low Low
Environmental cost perunit of biomass
Ideal Process Properties Ideal Process Properties
No sterilityNo genetically modified organisms (GMOs)AdaptableNo pure culturesLow capitalNo enzymesHigh product yieldsNo vitamin addition Co-products not required
Fuel PropertiesFuel Properties
Ethanol MTBE Mixed Alcohols
Octane high high high
Volatility high low low
Pipeline shipping no yes yes
Energy content low high high
Heat of vaporization high low low
Ground water damage no yes no
MixAlco ProcessMixAlco Process
Ferment DewaterDewaterPretreatPretreat ThermalThermalConversionConversion HydrogenateHydrogenate
Lime KilnLime Kiln
MixedMixedAlcoholAlcoholFuelsFuels
MixedMixedKetonesKetones
BiomassBiomass
HydrogenHydrogenCalcium CarbonateCalcium Carbonate
LimeLime
CarboxylateSalts
Storage + Pretreatment + Fermentation
Storage + Pretreatment + Fermentation
Biomass + Lime + Calcium Carbonate
Gravel
Air
Tarp Cover
DewateringDewatering
FermentFerment DewaterPretreatPretreat ThermalThermalConversionConversion HydrogenateHydrogenate
Lime KilnLime Kiln
MixedMixedAlcoholAlcoholFuelsFuels
MixedMixedKetonesKetones
BiomassBiomass
HydrogenHydrogenCalcium CarbonateCalcium Carbonate
LimeLime
CarboxylateSalts
Vapor-Compression DewateringVapor-Compression Dewatering
SaltSolution(Fermentor Broth)
Distilled Water
Filter
Salt Crystals
Compressor
Work
Effect of Feedstock Cost (800 tonne/h, 15% ROI) Effect of Feedstock Cost (800 tonne/h, 15% ROI)
-40 -20 0 20 40 Biomass Cost ($/tonne)
1.00
0.80
0.60
0.40
0.20
0.00
Alc
ohol
Sel
ling
Pri
ce (
$/ga
l)
Centralized ProcessingCentralized Processing
15.3 mi
50% of area planted
How do we increase engine efficiency?How do we increase engine efficiency?
• Electric hybrids (2 Electric hybrids (2 XX))• Better engines (2– 4 Better engines (2– 4 XX))
Meeting US gasoline needs by growing energy cane in BrazilMeeting US gasoline needs by growing energy cane in Brazil
1 × 2 × 3 ×
Meeting US gasoline needs by growing sweet sorghum in United StatesMeeting US gasoline needs by growing sweet sorghum in United States
1× 2× 3×
ConclusionConclusion
• Reduce wastesReduce wastes• Cleaner airCleaner air• New agricultural marketsNew agricultural markets• Energy securityEnergy security• Improve balance of paymentsImprove balance of payments• Address global warmingAddress global warming• Address energy shortageAddress energy shortage• More flexible international relationsMore flexible international relations• Benefit developing nationsBenefit developing nations