Biodiesel production from waste frying oil and its application to a diesel engine

Abstract

AbstractA transesterification reaction of Waste Frying Oil (WFO) with methanol in the presence of a sodium hydroxide catalyst was performed by means of two different methods: a one-step and a two-step. The effects of NaOH concentration and the molar ratio of methanol to WFO on the conversion of WFO to biodiesel were investigated and optimized for both methods. The results showed that, for one-step method, the optimal parameters for maximum biodiesel yields were found to be methanol to WFO molar ratio of 5:1, catalyst concentration of 0.7 wt% of WFO, reaction temperature of 50°C, reaction time of 1 h and stirring speed of 200 rpm, whereas the maximum biodiesel yield reached 95%. While, for the two-step method, the optimal parameters were 3.5:1 and 0.49 wt% of WFO for the first step, and 1.5:1 and 0.21wt% of WFO for the second step, whereas the maximum biodiesel yield reached 88.3% and 96.4%, respectively. Other parameters were the same as for one-step method. The two-step method enhances the yields of biod...