Optimization of operation conditions for biodiesel preparation from soybean oil using an electric field

The acceleration of the biodiesel-glycerol separation has attracted the interest of many researchers in a quest to improve biodiesel production efficiency and reduce the overall production time. This has played a pivotal role in lowering the production cost and reducing the demand for other nonrenewable sources of energy. In the present study, the transesterification of soybean oil into biodiesel was done using methanol and sodium hydroxide (as a catalyst) under an applied electric field. Response surface methodology (RSM) via Box-Behnken design (BBD) was applied to evaluate the influences of transesterification response on the reaction parameters of biodiesel production. Analysis of variance (ANOVA) was adopted to investigate several parameters of the quadratic polynomial model. The optimum condition was found under an applied electric field of 5 kV at a catalyst concentration, molar ratio of methanol to oil, reaction temperature, and stirring rates of 1 wt.%, 6:1, 60 °C, and 450 rpm respectively. During the transesterification process, the biodiesel yield reached 96.85% within 180.0 s. This is a huge improvement as compared with the conventional biodiesel preparing method which takes more than 2 h to obtain similar biodiesel yield.