Optimization of Continuous Biodiesel Production from Xanthoceras Oil via Transesterification in Supercritical Methanol

Biodiesel production from non-edible xanthoceras oil via supercritical methanol transesterification in a continuous fixed bed reactor using TiO2 as the catalyst was demonstrated in this work. Response surface methodology (RSM) based on central composite rotatable design (CCRD) was used to design the experiment and analyze three operating parameters: reaction temperature, reaction pressure and methanol/oil volume ratio. The optimum process conditions for the biodiesel yield were determined by solving the regression model equation and by analyzing the response surface and contour with Design Expert software. A statistical model predicted that the optimum yield of biodiesel was 98.89% at the following optimized reaction conditions: reaction temperature of 380.68 degrees C, reaction pressure of 22.07 MPa and methanol/oil volume ratio 3.03. Verification experiments further confirmed the validity of the predicted model, demonstrating that the methodology may be useful for optimization of industrial biodiesel production.