A Comparative study of KOH/Al2O3 and KOH/NaY catalysts for biodiesel production via transesterification from palm oil

Typically, biodiesel, a possible substitute for diesel fuel, is produced from the transesterification of vegetable oil or animal fat with methanol in the presence of a homogeneous base catalyst. In the conventional homogeneous catalysts, however, undesired side reactions occur and a separation step to remove the catalysts is required. Therefore, heterogeneous catalysts have been receiving the most attention for replacing homogeneous catalysts. This research is focused on the production of biodiesel from palm oil by using heterogeneous catalysts. Two types of catalysts, KOH/Al2O3 and KOH/NaY, were applied to determine the optimum condition for biodiesel production. Several parameters which may influence the quality of the produced biodiesel were investigated, including the reaction time, %wt. KOH loading, molar ratio of oil to methanol, amount of catlyst, reaction temperature and stirrer speed. The best result was obtained with Al2O3 loaded with 25% wt. KOH at 60C, with a 1:15 molar ratio of palm oil to methanol, a reaction time of 2 hours, and a catalyst amount of 3 g. The biodiesel yield was 91.07%, while NaY gave the same yield with 10% wt. KOH at 60C, with a 1:15 molar ratio of palm oil to methanol, a reaction time of 3 hours and a catlyst amount of 6 g.