Modeling and optimization of biodiesel production from soybean oil

Due to the increasing environmental pollution and the reduction of fossil fuel resources, the choice of a suitable alternative for non-renewable fuels has been given much attention. Among several alternative fuels, biodiesel is also clean and is produced from renewable sources. In this work, the mathematical modelling and optimization of the catalytic transesterification process for producing soybean oil biodiesel by MATLAB software and differential evolution algorithm has been investigated. The potassium hydroxide was selected as a homogenous catalyst for transesterification reactions in a batch reactor. Based on the experimental data, a model has been proposed to predict the biodiesel production in the catalyst concentration range of (0.4-1wt%), methanol to oil molar ratio range of (5-12) and temperature range of (25-65 °C). In addition, the unknown kinetic parameters of this model have been calculated. There was a good consistency between the model and experimental data. The modeling results showed that there is a relationship between biodiesel yield and effective parameters (temperature, oil to alcohol molar ratio and catalyst concentration). By increasing the temperature and oil to alcohol molar ratio and decreasing the catalyst concentration, the yield of biodiesel increases. Finally, the model was assisted to find the optimal conditions of transesterification reaction to maximize biodiesel yield. In the optimal conditions (catalyst concentration of 0.4501 wt%, molar ratio of methanol to oil of 15 and temperature of 70°C) the biodiesel yield reached 96.87%.