27-08-2014, 02:15 PM
Alternative Fuels:Ethanol
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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
How is it made
Ethanol can be made by fermenting almost any material that contains starch.
Most of the ethanol in the U.S. is made using a dry mill process.
In the dry mill process, the starch portion of the corn is fermented into sugar then distilled into alcohol
Prior to fermentation, high-value chemicals are removed from the biomass. These include fragrances, flavoring agents, food-related products, and high value nutraceuticals with health and medical benefits.
There are two main valuable co-products created in the production of ethanol: distillers grain and carbon dioxide. Distillers grain is used as a highly nutritious livestock feed while carbon dioxide is collected, compressed, and sold for use in other industries.
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.
Conclusion
Do the benefits outweigh the costs associated with ethanol production?
Ethanol helps communities to meet clean air standards, farmers to find new markets for their products, and America to replace foreign crude oil with a renewable source grown domestically.