Microwave assisted two step in situ method for biodiesel production from jatropha Curcas L. Seed

Abstract

This study explored the development of two steps process in a batch reactor system capable of operating in a microwave oven irradiation for biodiesel production from jatropha seed by using in–situ method. The first step, in-situ esterification, converted the free fatty acid by H!SO! as acid catalyst and the second step, in-situ transesterification converted the triglycerides by KOH 5N in ethanol as base catalyst in the microwave system. This was also the first investigation, which carried out twostep process from jatropha seed with out any washing and purification between esterification step and transesterification step. Furthermore, microwave irradiation assisted extraction of oil from Jatropha curcas seed with different solvent was carried out for two size seed with diameters of A<0.5 mm & 0.5<B<1.1 mm. The study concluded that maximum oil efficiency of 77.78% and 67.76 % were obtained for jatropha curcas seeds for size A and B respectively in 20 minute with ethanol by microwave system. Response surface methodology (RSM) was employed to examine the relationship between process variables and predicting the optimal conditions. The highest conversion of 93.84% at optimum reaction conditions of 31.07 minute irradiation time, 10.32% (V/W) ratio of ethanol to seed, 10.32 %wt catalyst amount, and 270 rpm agitation speed was achieved for size A in step 1. For size B the highest conversion of 90.19% at optimum reaction conditions of 35.5-minute irradiation time, 11.2%(V/W) ratio of ethanol to seed, 7.95%wt catalyst amount, and 285.12rpm agitation speed was reached. The highest final biodiesel conversion of 92.95% at optimum reaction conditions of 33.07 minute irradiation time, 13.82ml catalyst amount, and 202.64rpm agitation speed was achieved for size A in step 2. For size B the highest biodiesel conversion 92.67 at the same optimum reaction conditions for seed size. The final product was found to be in a reasonable agreement with EN-14214 European standard for physical properties.