Why BioFuel?
Biodiesel is the name of a clean burning alternative fuel, produced from vegetable or animal fats and oils. Biodiesel contains no petroleum, but it can be blended at any level with petroleum diesel to create a biodiesel blend. It can be used in compression-ignition (diesel) engines with little or no modifications. Biodiesel is simple to use, biodegradable, nontoxic, and essentially free of sulfur and aromatics.
Biodiesel is made through a chemical process called transesterification whereby the glycerin is separated from the fat or vegetable oil. The process leaves behind two products -- methyl esters (the chemical name for biodiesel) and glycerin (a valuable byproduct usually sold to be used in soaps and other products). The production process uses vegetable oil, lye and methanol or ethanol as the inputs.
Although some media attention has been paid to using straight vegetable oils in diesel motors, biodiesel is a different product. The process removes and breaks larger and more viscous glycerol ester molecules that do not combust well in modern diesel engines. Biodiesel in the 21st century has moved out of experimental and niche markets and into the mainstream. It can be used in any diesel vehicle in pure form or blended in any proportion with regular petro-diesel. In 2001 the American Society for Testing and Materials (ASTM) created the new standard, #6751, for biodiesel paving the way for car manufacturers to have consistent biodiesel to test in their diesel engines. The Environmental Protection Agency has also helped with standardizing biodiesel for on-road use. Tier I and Tier II tests by the EPA established biodiesel standards as a clean alternative to diesel. It has become attractive to public transportation providers who are concerned about exposing adults and children to toxins and carcinogens
Opportunity
The production of biofuels is an opportunity to diversify agricultural activity in the developing world, reduce dependence oil and contribute to the economic growth in a sustainable manner. The varying prospects for biofuel production and use in developing countries are related to the types of feedstock produced and a range of economic factors. For AEI, the most important determinants have been explored, these include:
- The size of the national and regional market
- The infrastructure investments needed
- The supportiveness of the political regime
- The options for exports
- The local market and price of the feedstocks used for biofuel production
Ethanol
Ethanol is a pure distilled alcohol that is produced from the fermentation of sugar starches. It is a gasoline replacement but can also be blended with gasoline to create a fuel blend. The ethanol yield derived form sugarcane is roughly eight times that derived from corn. Ethanol and biodiesel deliver the highest percent reduction in net CO2 emissions when used as fuel replacements. Production Process The basic steps for large scale production of ethanol are: microbial (yeast) fermentation of sugars, distillation, dehydration, and denaturing.
Ethanol is produced by microbial fermentation of the sugar. Production of ethanol from sugarcane (sugarcane requires a tropical climate to grow productively) returns about 8 units of energy for each unit expended compared to corn which only returns about 1.34 units of fuel energy for each unit of energy expended. Carbon dioxide, a greenhouse gas, is emitted during fermentation and combustion. However, this is canceled out by the greater uptake of carbon dioxide by the plants as they grow to produce the biomass. When compared to gasoline, depending on the production method, ethanol releases less or even no greenhouse gases. Distillation For the ethanol to be usable as a fuel, water must be removed. Most of the water is removed by distillation, but the purity is limited to 95-96% due to the formation of a low-boiling water-ethanol azeotrope. The 96% purity ethanol may be used as a fuel. Dehydration Currently, the most widely used purification method is a physical absorption process using a molecular sieve.