An experimental study & analysis of effects of different parameters of microwave in production of bio-diesel

Abstract

A novel and rapid method for transesterifying cottonseed oil into bio-diesel using a domestic microwave oven (MW) has been developed in the present study. Five parameters were investigated to see their effect on bio-diesel yield output. These were input power, reaction time, oil-to-methanol molar ratio, turntable speed, and fan cooling speed. The respective values used for experimentation were 200 W to 500 W, 4 to 11 minutes, 1:4.5 to 1:12, 10 to 40 rpm, and 800 to 1500 rpm and the volume of the catalyst was kept constant at 1%. The experimental results of microwave study were compared to the traditional magnetic stirrer (MS) approach for the same molar ratio and catalyst amount. The optimum parameters for the transesterification process assisted by the domestic microwave oven were obtained such as methanol to oil molar ratio (1:4.5), potassium hydroxide catalyst concentration (1% (w/w)), reaction time (11 minutes), turntable speed (40 rpm) and cooling fan speed (1500 rpm). The corresponding yield of cottonseed bio-diesel (CBD (MW)) was 99.5 percent. Compared with the contemporary MS approach for the same molar ratio and catalyst number, the yield of CBD (MS) was recorded in 25 minutes as 61.23 percent. It was also found that the turntable speed and cooling fan rpm of the improved microwave oven greatly, influenced the yield of bio-diesel and facilitated better utilization of microwave energy in mixing and avoid overheating of the sample mixture. A drastic reduction in microwave input power consumption was observed as compared to the pragmatic MS approach. The findings of this study have established the utility of energy-efficient, updated domestic microwave oven in the generation of bio-diesel on a small scale.