Biodiesel production from fish waste oil by combination of mechanical stirrer and microwave

The purpose of the present study is to produce biodiesel from fish waste oil and methanol by combination of mechanical stirrer and microwave as a technique to accelerate this. In this research, a microwave system was used including microwave source, stirrer, spiral tube and decantor. With the help of this system, the effect of molar ratio of alcohol to oil (4 to 1, 6 to 1 and 8 to 1), catalyst concentration (0.5, 1 and 1.5 weight percent of oil), reaction time (5, 15 and 25 min) and microwave time (0.5, 1.5 and 2.5 min) on the conversion of fatty acid to methyl ester. For analyzing the obtained results, the response surface method and Box Behnken layout were used in Design Expert 10.0 software. After analyzing the data and optimizing the biodiesel production reaction, it was found that the highest percentage of biodiesel conversion (92.62%) was found in the catalyst concentration of 1.13%, the reaction time of 24.61, the molar ratio of alcohol to oil of 5.55 and the microwave time of 0.5 minute. The regression model between independent variables and dependent variable (percent conversion) was obtained as a quadratic equation with R2 = 0.9953.