Effects of Important Parameters on Biodiesel Production using Heterogeneous Potassium Carbonate/Alumina Catalyst and Rapeseed Oil

Biodiesel, due to its environmental benefits and similar properties with diesel, is considered as a fossil fuel alternative. Rapeseed oil is used to produce biodiesel in presence of K2CO3/Al2O3. For catalyst preparation K2CO3 was loaded on the Al2O3 as support using impregnation. Taguchi’s experimental setup was used in a completely randomized design with two replications for transesterification reaction and investigating the effects of reaction time, temperature and catalyst concentration on biodiesel production efficiency and to optimize the number of experiments. Also, molar ratio of 15 to 1 (alcohol:oil), catalyst concentrations of 0.5, 1, 1.5, 2, 3 and 5 wt.%, reaction temperatures of 55, 65 and 75 °C, reaction times of 0.5, 1, 1.5, 2, 2.5 and 3 hr. and stirring rate of 600 rpm was used for transesterification reaction. Highest biodiesel yield (99%) was obtained by transesterification process at 65 °C using 2 wt. % of K2CO3/Al2O3 for 2 hr. Comparing these results to other researcher’s results shows that the loading ratio of K2CO3 compared to KNO3 and Ca(NO3)2 can increase the biodiesel production efficiency in alumina-based catalysts. Analysis of variance analysis with regard to catalyst, reaction time and temperature variables indicates that temperature changes have no significant effect on the efficiency of methyl ester production, but the effects of time and catalyst concentration on the reaction rate is quite significant.