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Ethanol

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>==Hey, it sounds good, but are there problems with ethanol?==

Brazil has expanded it's use of ethanol so much that they require little or no gasoline.

Here's a link to a News Leader article about a proposed local ethanol plant that will use a tremendous amount of water.

http://www.news-leader.com/apps/pbcs.dll/article?AID=2006611110365


Webster County Groundwater Planning Commitee Reports

http://www.jrbp.missouristate.edu/ethanol/index.shtml

Is there actually a net energy gain when ethanol is produced?

In other words, does the production of ethanol consume more energy than the resulting ethanol provides? Some people don't think so.

http://petroleum.berkeley.edu/papers/Biofuels/NRRethanol.2005.pdf

Energy outputs from ethanol produced using corn, switchgrass, and wood biomass were each less than the respective fossil energy inputs. The same was true for producing biodiesel using soybeans and sunflower, however, the energy cost for producing soybean biodiesel was only slightly negative compared with ethanol production. Findings in terms of energy outputs compared with the energy inputs were: � Ethanol production using corn grain required 29% more fossil energy than the ethanol fuel produced. � Ethanol production using switchgrass required 50% more fossil energy than the ethanol fuel produced. � Ethanol production using wood biomass required 57% more fossil energy than the ethanol fuel produced. � Biodiesel production using soybean required 27% more fossil energy than the biodiesel fuel produced (Note, the energy yield from soy oil per hectare is far lower than the ethanol yield from corn). � Biodiesel production using sunflower required 118% more fossil energy than the biodiesel fuel produced.

Why is so much water required?

http://www.ncga.com/ethanol/pdfs/031506USDACostOfProduction.pdf

Water Use

Water is essential in producing ethanol, particularly in the grinding, liquefaction, and fermentation processes. The amount of water used per gallon of ethanol has declined significantly in recent years. Old ethanol plants used more than 15 gallons of water per gallon of ethanol; among the plants surveyed in 2002, water use ranged from less than 1 gallon to 11 gallons per gallon of ethanol and averaged 4.7 gallons per gallon of ethanol (fig. 10). Ethanol plants require processed water to produce ethanol. Water discharged from plants (wastewater) contains organic compounds that cannot be discharged into rivers. The wastewater discharge must be treated in the ethanol plant or connected to local wastewater treatment facilities. New ethanol plants have zero discharge of wastewater and do not need to connect to the local wastewater treatment service, thus allowing for plants to locate in more rural locations closer to the sources of raw materials. To decrease wastewater in the ethanol plants, anaerobic digesters are used to degrade the organic compounds. This process produces methane gas, which can be used as an alternative energy source for the DDG dryer. Anaerobic digesters remove 85 to 95 percent of organic compounds. The removal of these compounds can eliminate the need for traditional waste treatment, which can often save $500,000 to $1 million in capital investment costs.



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This page was last modified on 18 November 2010, at 07:53.
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