EXPERIMENTAL INVESTIGATIONS ON COMBUSTION AND EMISSION CHARACTERISTICS OF BIOFUEL PREPARED FROM COTTON SEED OIL AT VARIOUS INJECTION PRESSURES

Biodiesel is a fuel comprised of mono-alkyl esters of long-chain fatty acids derived from vegetable oils or animal fats. Biodiesel is now well-adopted fuel with benefit of being a renewable energy source and decreasing pollutant. The cotton seed oil contains 18 - 26% and it contains long chain fatty acid. Cotton seed oil is rich in palmitic acid (22-26%), oleic acid (15-20%), linoleic acid (49-58%) and 10% mixture of other acid. The FFA present in the raw cotton seed oil is 3.7%. After transesterification, it is reduced to 1.9%. Similarly, the corresponding value of viscosity also is reduced from 34 Cst to 11.1 Cst. With the recent developments in the fuel injection system and more sophisticated components to meet emission norms, a good variety of fuels can be successfully used in Compression Ignition (CI) engines. Cotton seed oil can be easily blended with diesel in three different blends B10, B20 and B30. Initially the properties of cotton seed oil like calorific value, density, viscosity, %FFA, iodine value, and saponification value were identified and compared with diesel properties. A single cylinder, water cooled, direct injection CI engine at a constant engine speed of 1500 rpm was used for testing at various load conditions. The combustion and emission performance of the engine was obtained and compared with that of diesel. The effect of injection pressure on the engine performance was observed by varying the fuel injection pressure from 195 bar to 215 bar. From combustion analysis B30 blend seems to have better thermal efficiency compared to diesel at high loads. The NOx level was minimum for B30 blend and was better for all blends compared to diesel at high injection pressures.