ETHANOL AS FUEL SUPPLEMENT ITS POTENTIAL AND ENVIRONMENTAL IMPACTS

Abstract

In view of increasing consumption and price of gasoline, different extenders have been identified with the passage of time. Ethanol is one of them and worthy of consideration as fuel extender, or even as a substitute for gasoline in internal combustion engines. The miscibility of ethanol in gasoline is commonly known and the resulting blend is called Gasohol. This ethanol is immiscible with middle distillates like kerosene and avtur. However it is also miscible with diesel up to a certain limit. With this consideration a research study was undertaken to mix the ethanol derived from sugar industry with gasoline. Ethanol is produced by fermentation of biomaterial and waste like molasses, beggass, rice husk, corn, combs, paper pulp, potatoes, straws, saw dust, tropical grass including domestic wastes. In present study, ethanol from sugar industry of Pakistan has been used for the purpose of blending with gasoline along with certain stabilizers. This study was carried out to determine optimum conditions of mixing industrial ethanol with gasoline in Pakistan. Several samples of gasoline without ethanol and with in various prepositions percent by volume of rectified ethanol were evaluated on a CJ-5 Jeep with in line, six cylinders gasoline engine and a Suzuki Car 800cc with in-line, three cylinders gasoline engine. As a result of using these blends following benefits were achieved. Volumetric efficiency of fuel remains unchanged at the same time blend accommodated upto 40 percent industrial ethanol in the gasoline. Mechanical efficiency of the engine was improved while using 25 percent ethanol-blended gasoline. Field tests were conducted in actual traffic conditions on roads, cross country sites and downtown. Fuel consumption measurement tests were also conducted utilizing fuels gasoline without ethanol and with upto 25 percent blend of the ethanol. The results showed that the engines of the test vehicles performed better on a gasoline - ethanol blend than on gasoline alone, after adjustment of the carburetor. A complete range of lab analysis of locally available ethanol and its various blends with gasoline xvere also conducted have been included in this study. Stiochiometric air/fuel ratios were calculated on the basis of Wrangham and Lenz's model. Enlargements in the jet size of the carburetor were made according to Roger Lippman's calculations. The exhaust gas analysis from ethanol blended gasoline engines, led to conclusion that the blend reduces the emission levels of CO and HC upto 90 and 40 percent respectively.