Optimization of the technology for biodiesel preparation using solid alkali as heterogeneous catalyst

Mg/Al solid base catalysts were used in transesterification reaction for production of rapeseed biodiesel. The quadratic orthogonal rotation design with five factors was used to study the effect of of technology for production of biodiesel. The technological parameters including the amount of methanol, the amount of catalyst, temperature, reaction time and rotating speed were investigated. Functional models of yield to five factors were established by RSREG software in SAS8.1. Results show that the regression equation is significant, and the mathematical model for the simulation is presented; the effect order of five factors on yield is as follows:the amount of catalyst >the amount of methanol>rotating speed>reaction time>temperature. The optimum conditions for the transes terification reaction are 20% methanol and 6% catalystof rapeseed oil material, stirring speed 500 r/min，8 h of reaction time and 70℃ of temperature. The quality criteria of the biodiesel produced from rapeseed oil meet the same standards to ASTM of US and DINE of Germany, and the conversion ratio of rapeseed oil to biodiesel reaches 90%.