Ethanol as a Biofuel

   

   Ethanol is said to be a renewable energy source because it can be made by the action of microorganisms and enzymes through fermentation of grains and other agricultural sources such as switchgrass and sugarcane. The crops themselves grow, of course, by converting light energy form the sun to chemical energy through photosynthesis. Once obtained, the ethanol can be combined with gasoline in varying proportions and used in internal combustion engines.  During the year 2007, the United States led the world in ethanol production with 6.5 billion U.S.gallons, followed closely by Brazil with 5 billion gallons.

  Biobutanol,which is also called as biogasoline, is often claimed to provide a direct replacement for gasoline, because it can be used directly in a gasoline engines.When used as a replacement for gasoline, ethanol has a lower energy content, by about 34% per unit volume. This and other factors such as costs in energy required to produce the agricultural feedstock, especially corn, have created doubts about the wisdom of an ethanol-based program as a renewable energy source. Production of ethanol from corn is 5 to 6 times less efficient than producing it from sugarcane, and it also diverts production of a food crop into an energy source. World food shortages may be a result.

  Actually, a biofuel is a fuel that is derived from biological materials, such as plants and animals. Also biofuel can still be seen as fuel derived from organic matter (obtained directly from plants, or indirectly from agricultural, commercial, domestic, and/or industrial wastes).Examples of this carbon fixation occur in plants and microalgae through the process of photosynthesis. These fuels are made by a biomass conversion (biomass refers to recently living organisms, most often referring to plants or plant-derived materials). This biomass can be converted to convenient energy containing substances in three different ways: thermal conversion, chemical conversion, and biochemical conversion. This biomass conversion can result in fuel in solid, liquid, or gas form. This new biomass can be used for biofuels. Biofuels have increased in popularity because of rising oil prices and the need for energy security.

  Bioethanol is an alcohol made by fermentation, mostly from carbohydrates produced in sugar or starch crops such as corn, sugarcane, or sweet sorghum. Cellulosic biomass, derived from non-food sources, such as trees and grasses, is also being developed as a feedstock for ethanol production. Ethanol can be used as a fuel for vehicles in its pure form, but it is usually used as a gasoline additive to increase octane and improve vehicle emissions. Bioethanol is widely used in the USA and in Brazil. Current plant design does not provide for converting the lignin portion of plant raw materials to fuel components by fermentation.