Biodiesel from Fried Oil Using Microwaves, Ultrasounds and Heterogeneous Catalysis

To evaluate the efficiency of the transesterification of fried oils by using heterogeneous catalysis, three different systems have been compared: 1) flask in hot bath with magnetic stirrer; 2) flask in microwave oven with a stirring arm; 3) flask in ultrasound bath with a stirring arm. The CaO and SrO were used as heterogeneous catalysts. The transesterification has been carried out at 65 °C, using methanol/oil ratio 12:1 and catalyst load of 0.7%. The efficiency of the processes has been evaluated in terms of FAME yields. Results have shown that, using microwaves, the reaction is more efficient (88% yield with CaO, 85% with SrO) than using the classical hot bath system (78% with CaO, 76% with SrO). Good results have been obtained with the ultrasound system, in particular with CaO: the transesterification rate has been the fastest and the reaction was completed in about 30 minutes.
Proceedings of the 20th European Biomass Conference and Exhibition, 18-22 June 2012, Milan, Italy, pp. 1783-1785