With the modifications, these vehicles can use straight gasoline or any blend of ethanol up to 85 percent. Ethanol can be fermented from many sources of starch, including corn, wheat, grain sorghum, barley, and potatoes, and from sugar crops such as sugar cane and sweet sorghum.
Because there has been has been an abundant supply of corn, most of the ethanol made in the United States is from corn. Most of the ethanol is produced in the Midwest and Upper Midwest where ethanol plants are close to and have a consistent supply of corn, access to water resources, and have livestock production nearby. A by-product of ethanol production is distillers grains, which can be fed to livestock either wet or dried. Because the wet distillers grains are perishable and heavy, which adds to transportation costs, they are usually used within a mile radius of an ethanol plant.
Distillers grains are more stable and easier to transport when an ethanol producer dries them, however that increases the energy cost for the ethanol producer. Distillers grains retain many of the nutrients from corn, since only the starch has been removed. Due to the high fiber content most of the distillers grains are fed to beef and dairy cattle, however, they can also be used as poultry and pig feed.
In most of the newer ethanol plants, also known as "dry grind" plants, the corn kernels are finely ground into small particles. Then water is added to the ground corn along with enzymes to convert the starch for fermentation. Ethanol contains less energy per gallon than gasoline, to varying degrees, depending on the volume percentage of ethanol in the blend. Energy is required to turn any raw feedstock into ethanol. Ethanol produced from corn demonstrates a positive energy balance , meaning that the process of producing ethanol fuel does not require more energy than the amount of energy contained in the fuel itself.
Cellulosic ethanol improves the energy balance of ethanol because the feedstocks are either waste, co-products of another industry wood, crop residues , or are dedicated crops—such as switchgrass and miscanthus—with low water and fertilizer requirements compared to corn.
While graphite is View Full Term. By clicking sign up, you agree to receive emails from Corrosionpedia and agree to our Terms of Use and Privacy Policy. Ethanol fuel is a renewable fuel that is commonly domestically produced or fermented from agricultural waste, grain or corn.
Ethanol fuel is also produced in a chemical extraction from ethylene via hydration. Ethanol fuel is ethyl alcohol, the same type of alcohol found in alcoholic beverages. Ethanol fuel is used primarily as a supplement to motor spirit, gasoline or petrol.
It is most often used in internal combustion engines. Pure ethanol is not sold alone; it is generally mixed with gasoline in various concentrations making it a transitional fuel. For example, E85 is a common mixture containing 85 percent ethanol and 15 percent gasoline. This cellulosic ethanol is considered an advanced biofuel and involves a more complicated and costly production process than fermentation. However, there are large potential non-food crop sources of cellulosic feedstocks.
Trees, grasses, and agricultural residues are potential feedstocks for cellulosic ethanol production. Trees and grasses require less energy, fertilizers, and water to grow than grains do, and they can also be grown on lands that are not suitable for growing food crops. Scientists have developed fast-growing trees that grow to full size in 10 years. Many grasses can produce two harvests a year for many years without annual replanting. Despite the technical potential for cellulosic ethanol production, economical production has been difficult to achieve and only relatively small amounts of cellulosic fuel ethanol have been produced United States.
In the s, ethanol was a major lighting fuel. During the Civil War, a liquor tax was placed on ethanol to raise money for the war. The tax increased the price of ethanol so much that it could no longer compete with other fuels such as kerosene. Ethanol production declined sharply because of this tax, and production levels did not begin to recover until the tax was repealed in In , Henry Ford designed his Model T, a very early automobile, to run on a mixture of gasoline and alcohol.
Ford called this mixture the fuel of the future. In , when Prohibition began, ethanol was banned because it was considered an alcoholic beverage. It could only be sold when mixed with petroleum. Ethanol was used as a fuel again after Prohibition ended in Ethanol use increased temporarily during World War II when oil and other resources were scarce. In the s, interest in ethanol as a transportation fuel was revived as oil embargoes, rising oil prices, and growing dependence on imported oil increased interest in alternative fuels.
Since that time, ethanol use and production has been encouraged by tax benefits and by environmental regulations that require cleaner-burning fuels.
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