Ethanol as fuel:
Ethanol or alcohol can be used as fuel very effectively, as a bio-fuel alternative to gasoline. In many of the countries it is used in running vehicles. As it is easier to manufacture and process, it is steadily becoming a promising alternative to gasoline almost throughout the world. It is mainly processed from sugar cane – a very common agricultural produce. Anhydrous ethanol, i.e., ethanol having less than 1% of water, can be blended very effectively with gasoline in varying proportion. 10% ethanol blended gasoline is common in most of the countries for running motor vehicles.
Current interest in ethanol mainly lies in ‘bio-ethanol’ that is produced from agricultural based starch or sugar. Basically, carbon-based feedstocks are used for bio-ethanol production. Agricultural feedstocks are considered renewable. Feedstock such as sugar cane, bagasse, miscanthus, sugar beet, sorghum, grain sorghum, switch-grass, barley, hemp, kenaf, potatoes, sweet potatoes, cassava, sunflower, fruit, molasses, corn, stover, grain, wheat, straw, cotton and other biomass can be used for production of bio-ethanol.
The basic steps for large scale production of bio-ethanol are: (a) microbial (yeast), i.e., fermentation of sugars; (b) distillation; (c) dehydration and (d) denaturing.
There has been considerable debate about actual usefulness of bio-fuel like bio-ethanol. Replacing fossil fuels by bio-ethanol take large area of arable land mass, which would have been cultivated for food crops. Moreover, the energy and pollution balance of the whole cycle of ethanol production is also not known.
