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  1. 1. Alternative Fuels: Ethanol
  2. 2. What is ethanol?  GM Commercial  CH3CH2OH  Ethanol is a clean-burning, high-octane fuel that is produced from renewable sources.  At its most basic, ethanol is grain alcohol, produced from crops such as corn.  Since pure 100% ethanol is not generally used as a motor fuel, a percentage of ethanol is combined with unleaded gasoline, to form E10 and E85  E10: 10% ethanol and 90% unleaded gasoline, is approved for use in any US vehicle  E85: 85% ethanol and 15% unleaded gasoline, is an alternative fuel for use in flexible fuel vehicles (FFVs).
  3. 3. How is it made?  Ethanol production is based on two major techniques (i) Chemical Synthesis (ii) Fermentation  Catalytic hydrolysis of Ethylene derived from petroleum CH2 = CH2 + H2O CH3CH2OH  Fermentation sources have four categories of feed stocks : Sugar containing materials, Carbohydrates, Lignocel-Lulosics and urban and industrial wastes.
  4. 4. Ethanol preparation from wood by acidic hydrolysis.
  5. 5. Ethanol preparation from sugarcane.
  6. 6. Fermentation Systems  The conversion of cellulose, starch and sugars to ethanol (C2H5OH) is : (C6H10O5)n + nH2O nC6H12O6 C12H22O11 +H2O 2C6H12O6 C6H12O6 2C2H5OH + 2CO2  The conventional batch process for production of Ethanol from molasses was developed in days of inexpensive energy.  The concept of continuous tower fermentation was developed for the brewing industry in Britain in the 1960  Some factors limit the use of tower fomenters, like for e.g. as the feed sugar concentration is increased (15-20 %) to raise the Ethanol concentration, it increases the yeast floc washout in tower with an increase in the hydraulic loading.
  7. 7. Minimizing the cost of preparation of ethanol  Significant improvements in ethanol production technology are necessary in order to reduce production costs.  A balance must be struck among the three principal goals of ethanol fermentation. (i) High substrate utilization (ii) High ethanol productivity (iii) High ethanol concentration in product stream to the recovery section.  In batch fermentations, complete sugar consumption means long fermentation times and, hence low average ethanol productivity by volume with continuous stirred tank fermenters, it is common to have maximum ethanol productivity at a dilution rate as near to maximum as possible, leaving some residual sugar in fermenter effluent.
  8. 8. Energy Balance of Ethanol
  9. 9. Energy Balance  Although CO2 is released during ethanol production and combustion, it is recaptured as a nutrient to the crops that are used in its production.  Unlike fossil fuel combustion, which unlocks carbon that has been stored for millions of years, use of ethanol results in comparatively lower increases to the carbon cycle.  Ethanol also degrades quickly in water and, therefore, poses a smaller risk to the environment than an oil or gasoline spill.  Research studies from a variety of sources have found ethanol to have a positive net energy balance. The most recent, by the U.S. Department of Agriculture, shows that ethanol provides an average net energy gain of at least 77%.  It takes less than 35,000 BTUs of energy to turn corn into ethanol, while the ethanol offers at least 77,000 BTUs of energy. Thus ethanol has a positive energy balance—meaning the ethanol yields more energy than it takes to produce it.
  10. 10. Impact on air quality  Using ethanol-blended fuel has a positive impact on air quality. By adding oxygen to the combustion process which reduces exhaust emissions—resulting in a cleaner fuel for cleaner air.  Ethanol reduces the emissions of carbon monoxide, VOX, and toxic air emissions:  Since ethanol is an alcohol based product, it does not produce hydrocarbons when being burned or during evaporation thus decreasing the rate of ground level ozone formation.  Ethanol reduces pollution through the volumetric displacement of gasoline. The use of ethanol results in reductions in every pollutant regulated by the EPA, including ozone, air toxins, carbon monoxide, particulate matter, and NOX.
  11. 11. Impact on energy independence  Since it is domestically produced, ethanol helps reduce America's dependence upon foreign sources of energy. U.S. ethanol production provides more than 4 billion gallons of renewable fuel for our country.  Current U.S. ethanol production capacity can reduce gasoline imports by more than one-third and effectively extend gasoline supplies at a time when refining capacity is at its maximum.  According to the Energy Information Administration, the 7.5 billion gallon ethanol production level in the recently enacted Renewable Fuels Standard could reduce oil consumption by 80,000 barrels per day.
  12. 12. Impact on economy  In a 1997 study The Economic Impact of the Demand for Ethanol, Northwestern University’s Kellogg School of Management found that:  During ethanol plant construction, approximately 370 local jobs are created.  During ethanol plant operation, up to 4,000 local jobs are created.  Ethanol plant construction creates $60 million to $130 million in additional income.  Ethanol plant operation creates $47 million to $100 million in additional income.  American-made, renewable ethanol directly displaces crude oil we would need to import, offering our country critically needed independence and security from foreign sources of energy.  The U.S. Department of Agriculture has concluded that a 100 million gallon ethanol facility could create 2,250 local jobs for a single community. Ethanol production creates domestic markets for corn and adds 4-6 cents a bushel for each 100 million bushels used. Better prices mean less reliance on government subsidy programs not to mention higher income and greater independence for farmers.
  13. 13. Impact on auto industry  Ethanol could be the alternative fuel source that catapults sales of American auto manufacturers.  GM and Ford are looking for environmental fixes that are quicker and cheaper than the more costly hybrids and futuristic fuel cells. Both companies started promoting flexible-fuel vehicles (FFVs) aggressively this year.  General Motors tied their new campaign "Live Green, Go Yellow.'' to not only Super Bowl Sunday but the opening of the Winter Olympics as well.  Since only about 600 of the nation's 170,000 filling stations sell E85, both companies have begun programs to install E85 pumps at more stations.
  14. 14. Problems with Ethanol       Odors as a public nuisance, ex: New Energy Ethanol Plant here in South Bend Green house gas emissions have sometimes shown to be equivalent to those of gasoline (data is often inconclusive) Environmental performance of ethanol varies greatly depending on the production process Costs involved with building new facilities for ethanol production New ways to maximize crop production are necessary Research is needed to refine the chemical processes to separate, purify and transform biomass into usable fuel
  15. 15. Problems with Ethanol  Soil erosion from increased agriculture  Conversion of forests into agricultural land—which could lead to future environmental dilemmas…
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