ethanol-gasoline fuels: are they effective? presented by steve cavadeas
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Ethanol-Gasoline Fuels: Ethanol-Gasoline Fuels: Are they Effective?Are they Effective?
Presented by Steve Presented by Steve CavadeasCavadeas
OutlineOutline
BackgroundBackground Ethanol production processEthanol production process Pros and ConsPros and Cons ConclusionsConclusions
1990 Ammendment to 1990 Ammendment to Clean Air ActClean Air Act
An attempt to reduce severe smog areasAn attempt to reduce severe smog areas Reduce CO emissions in winterReduce CO emissions in winter
– Requires an oxygenateRequires an oxygenateAllows more complete combustionAllows more complete combustionEthanol, MTBEEthanol, MTBE
The federal RFG program was introduced in 1995The federal RFG program was introduced in 1995 RFG is currently used in 17 states RFG is currently used in 17 states About 30 percent of gasoline sold in the U.S. is About 30 percent of gasoline sold in the U.S. is
reformulated. reformulated. Each oil company prepares its own formula. Each oil company prepares its own formula.
OptionsOptions
MTBE vs. EthanolMTBE vs. Ethanol Corn vs. BiomassCorn vs. Biomass Dry milling vs. Dry milling vs.
Wet millingWet milling
Dry Milling ProcessDry Milling Process
Wet Milling ProcessWet Milling Process
Biomass ProcessBiomass Process
Wet Milling DetailsWet Milling Details
SteepingSteeping– Grain is soaked in sulfurous acid for 24 to 48 hoursGrain is soaked in sulfurous acid for 24 to 48 hours
Grinding and SeparationGrinding and Separation– Grain is separated into gluten, fiber, starch, and germGrain is separated into gluten, fiber, starch, and germ– Oil is extracted from germ using benzeneOil is extracted from germ using benzene
By-ProductsBy-Products
Feed productFeed product– Fiber is extruded and heavy Fiber is extruded and heavy
steep water is added, then steep water is added, then dried.dried.
– Sold as feed for livestockSold as feed for livestock
Gluten MealGluten Meal– Gluten is filtered and driedGluten is filtered and dried– Sold as feed ingredient to Sold as feed ingredient to
poultry boiler operationspoultry boiler operations
ProductsProducts
StarchStarch– Can be processed Can be processed
further to producefurther to produce1.1. Modified or dried Modified or dried
corn starchcorn starch
2.2. Corn syrup Corn syrup (dextrose, (dextrose, fructose)fructose)
3.3. EthanolEthanol
Ethanol from Corn StarchEthanol from Corn Starch
LiquificationLiquification -amylase added to -amylase added to
cleave random cleave random -1,4 -1,4 and and -1,6-glucosidic -1,6-glucosidic bondsbonds
– Gluco-amylase added to Gluco-amylase added to digest digest -1,4-glucosidic -1,4-glucosidic bond from non-reducing bond from non-reducing endend
Ethanol from Corn StarchEthanol from Corn Starch
Yeast then added to resulting sugar for Yeast then added to resulting sugar for fermentation (40-50 hours).fermentation (40-50 hours).
CC66HH1212OO66 + 6 O + 6 O22 2 C 2 C22HH66O + 2 COO + 2 CO22
(6 separate reactions, (6 separate reactions, ∆G = -41.1 kcal/mol)∆G = -41.1 kcal/mol)
however, there is a problem… however, there is a problem…
Ethanol from Corn StarchEthanol from Corn Starch
Respiration can occur!Respiration can occur!
CC66HH1212OO66 + 6 O + 6 O22 6 CO 6 CO2 2 + 6 H+ 6 H22OO
((G = -686 kcal/mol)G = -686 kcal/mol)
Solution?Solution?– Get rid of OGet rid of O22
– Use organisms that preferentially fermentUse organisms that preferentially ferment
Ethanol from Corn StarchEthanol from Corn Starch
After fermentation, 8-10% EtOH in waterAfter fermentation, 8-10% EtOH in water– Distilled to approximately 190 proofDistilled to approximately 190 proof– Dehydrated to 200 proof using molecular Dehydrated to 200 proof using molecular
sievessieves Finally, 5% denaturant is added to render Finally, 5% denaturant is added to render
undrinkable (usually gasoline)undrinkable (usually gasoline)– Avoid beverage alcohol taxAvoid beverage alcohol tax
Product is sent to be mixed as 10 vol% Product is sent to be mixed as 10 vol% gasolinegasoline
Ethanol Production FacilitiesEthanol Production Facilities
Source: U.S. Energy Information Administration/Renewable Fuels Administrations
U.S. Ethanol ProductionU.S. Ethanol Production
0
500
1000
1500
2000
2500
3000
Mill
ion
s o
f G
allo
ns
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
Year
Source: U.S. Energy Information Administration/Renewable Fuels Administrations
BenefitsBenefits
Octane BoosterOctane Booster– Raises octane 2.5~3 numbersRaises octane 2.5~3 numbers
Allows for higher combustion ratesAllows for higher combustion rates Reduces harmful emissionsReduces harmful emissions
– CO emissions decrease by 26%CO emissions decrease by 26%– Fewer higher order hydrocarbons emittedFewer higher order hydrocarbons emitted
Large number of jobs for productionLarge number of jobs for production– 32% of corn harvested goes to production of 32% of corn harvested goes to production of
ethanolethanol
DrawbacksDrawbacks
Additional emissionsAdditional emissions– 15% NO15% NOxx
– 65% Organic emissions65% Organic emissions– 46% aldehydes46% aldehydes– 10% PAN, PPN10% PAN, PPN
Potent lachrymators and mutagens
Data from Data from Performance Evaluation of Alcohol-Gasoline Blends in 1980 AutomobilesPerformance Evaluation of Alcohol-Gasoline Blends in 1980 Automobiles. Coordinating Research Council. No 527. July, 1982.. Coordinating Research Council. No 527. July, 1982.
But then again…But then again…
New study from EPA New study from EPA suggests air quality is suggests air quality is highest in three highest in three decadesdecades
Depends on who you Depends on who you askask
Millions of Tons
1970 2003*
CO 197.3 93.7
NOx 26.9 20.5
PPN 12.2 2.3
SO2 31.2 15.8
VOC 33.7 15.4
Lead 0.221 0.003
*preliminary data
http://www.epa.gov/air/
Other DrawbacksOther Drawbacks
Energy loss!Energy loss!– 1 acre corn field creates ~ 330 gal EtOH1 acre corn field creates ~ 330 gal EtOH– Planting, growing, harvesting 1 acre requires Planting, growing, harvesting 1 acre requires
~1,000 gal fossil fuels~1,000 gal fossil fuels– 1 gal EtOH = 77,000 Btu1 gal EtOH = 77,000 Btu– 1 gal Gasoline = 114,000 Btu1 gal Gasoline = 114,000 Btu
Possible vapor lock in engines (older cars)Possible vapor lock in engines (older cars)– Not an issue with “forward pumping”Not an issue with “forward pumping”
More DrawbacksMore Drawbacks
Cost of production (2003)Cost of production (2003)– EtOH ~ $1.74 / gallonEtOH ~ $1.74 / gallon– Gasoline ~ $1.14 / gallonGasoline ~ $1.14 / gallon
State and Federal SubsidiesState and Federal Subsidies– ~$1 Billion/year given to ethanol producers~$1 Billion/year given to ethanol producers– This is added cost to consumerThis is added cost to consumer
ConclusionConclusion
Environmental benefits vs. Environmental benefits vs. cost/performancecost/performance
Other oxygenates available?Other oxygenates available?– ETBEETBE (Ethyl Tert-Butyl Ether) (Ethyl Tert-Butyl Ether)– TAME (Tertiary Amyl Methyl Ether)TAME (Tertiary Amyl Methyl Ether)– MTBEMTBE (Methyl Tert-Butyl Ether) (Methyl Tert-Butyl Ether)
What do you think?What do you think?
ReferencesReferences1.1. Performance Evaluation of Alcohol-Gasoline Blends in 1980 Performance Evaluation of Alcohol-Gasoline Blends in 1980
AutomobilesAutomobiles. Coordinating Research Council. No 527. July, . Coordinating Research Council. No 527. July, 1982. 1982.
2.2. Ethanol from Corn Wastes Energy?Ethanol from Corn Wastes Energy? Social Science. October Social Science. October 2001. Pg 6.2001. Pg 6.
3.3. Potential Air Quality Effects of Using Ethanol-Gasoline Fuel Potential Air Quality Effects of Using Ethanol-Gasoline Fuel Blends: A Field Study in Albuquerque, New Mexico. Blends: A Field Study in Albuquerque, New Mexico. Environ. Environ. Sci. Technol. Vol. 31, No. 11. 1997. Pgs. 3053-3061Sci. Technol. Vol. 31, No. 11. 1997. Pgs. 3053-3061
4.4. Renewable Fuels Association. Renewable Fuels Association. www.ethanolrfa.orgwww.ethanolrfa.org
5.5. U.S. Department of Energy. www.doe.govU.S. Department of Energy. www.doe.gov
6.6. American Corn Growers Association. www.acga.orgAmerican Corn Growers Association. www.acga.org
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