PREPARATION OF BIODIESEL BY TRANSESTERIFICATION OF WASTE COOKING OIL

Abstract

The increasing awareness of the depletion of fossil fuel resources and the environmental benefits of biodiesel fuel has made it more attractive in recent times. Its primary advantages with it being one of the most renewable fuels currently available and it is also non-toxic and biodegradable. It can also be used directly in most diesel engines without requiring extensive engine modifications. However, the cost of biodiesel is the major hurdle to its commercialization in. comparison to petroleum-based diesel fuel. The high cost is primarily due to the raw material, mostly neat vegetable oil. Used cooking oil is one of the economical sources for biodiesel production. The type of process that used to produce biodiesel is transesterification. Transesterification is the most common process which is used widely compared to other processes. This process is important to convert free fatty acid (FFA) in oil to ester. In this research, waste cooking oil is used as raw material with potassium hydroxide (KOH) as catalyst and methanol as a solvent. The reaction was carried out at constant temperature in an oil bath. The parameters that have been investigated during the reaction of esterification and transesterification were methanol-to-oil ratio and catalyst concentration respectively. The reaction temperature was fixed at 65°C. The biodiesel sample thus produced was tested to determine the fuel properties and was compared with the standards (ASTM D6751) for biodiesel B100. The optimized ratio of methanol- to-oil for maximum reduction of FFA contents in esterification is 3:7 (v/v) in 3h was 94.06 % (from 13.21% to 0.77%). The fuel properties of the biodiesel are in the range of ASTM standards expect for the kinematic viscosity in the case of .05% KOH. The biodiesel blends (B5 & B20) were compared with B100 and commercial diesel. Increase in the percentage of biodiesel in blend 'resulted in increase in acid number, viscosity and flash point. The Calorific value of B5 and B20 are reduced by 0.778% and 1.73% respectively compared to diesel. These increases in value are still within the limits of ASTM standards of Diesel. Therefore the result obtained showed that the blends B5 and B20 can be applied in diesel engines. Sufficient waste cooking is available in India to prepare blends.