PRODUCTION OF BIODIESEL BY THE ESTERIFICATION OF OLEIC ACID WHILE USING AMBERLYST 15 AS CATALYST

摘要

Biodiesel is a potential renewable and carbon neutral energy carrier. With the world's fossil fuel reserves and particularly liquid hydrocarbons being finite, biodiesel is a promising alternative as it can be used as a direct replacement for fossil diesel. One of the main problems with biodiesel production is the formation of soaps with the use of base homogenous catalysts due to the presence of fatty acids in non-pure raw materials. In order to avoid this undesired by product, the use of heterogeneous catalysts has gained more and more relevance due to the fact that it offers easier separation and reusability while avoiding soap formation which allows the use of feedstocks with higher amounts of free fatty acids. In this work the direct esterification of oleic acid in the presence of the heterogeneous catalyst Amberlyst 15 and ethanol was examined. The selection of alcohol was done based on the fact that ethanol can be obtained from natural sources while methanol is from petroleum based process. The catalyst and reactants were added to a 500 ml glass batch reactor while being stirred by a magnetic stirrer at 200 RPM and heated by circulating water in order to reach the desired reaction temperature. Studies over different reaction temperatures, alcohol to fatty acid molar ratios and catalyst amounts were performed to determine the effect that each variable has on the reaction and its yield. From the experimental data, it was concluded that the effect of temperature has a substantial effect on the reaction rate and the final conversion. Molar ratio and catalyst amount also significantly affects the conversion of oleic acid but to a lower degree than temperature. This technology is shown to be a good pre-esterification alternative for the purification of waste oils with high concentrations of free fatty acids.