Microwave Mediated Production of FAME from Waste Cooking Oil : Optimization of Process Parameters by RSM

In this study, the optimization of the biodiesel production process from waste oil using microwave with response surface methodology (RSM) was conducted. The microwave irradiation time and power in addition to the alcohol/oil mole ratio were chosen as process parameters. Also the fatty acid methyl ester (FAME) content (over 96.5%) and kinematic viscosity (1.9 similar to 5.5 cSt) were selected as response values. From basic experiments, the range of quantitative factors were set as following; 4 similar to 6 min, 400 similar to 600 W, and 7 similar to 9 for the microwave irradiation time and power, and alcohol/oil molar ratio, respectively. The optimum conditions for the methanolysis were 5.0 similar to 5.1 min, 481.3 similar to 525.5 W, 7.9 similar to 8.4, and 2.0 or 3.0 mg KOH/g for the microwave irradiation time and power, methanol/oil molar ratio, and each acid value, respectively. The FAME content and kinematic viscosity were predicted as 97.49 similar to 96.34% and 4.01 similar to 4.12 cSt, respectively, under the condition above. Under the optimum experimental conditions, the results showed that the FAME content and kinematic viscosity of 97.82 similar to 96.42% and 4.07 similar to 4.16 cSt, respectively were measured and the mean error rates were 0.22% and 0.98%, respectively.