Application of Response Surface Methodology in Conversion of Waste Edible Oil to Biodiesel

Biodiesel is produced by alkaline-catalyzed transesterification process,which is designed according to the 34 three center point small-factorial central composite design.The response surface methodology(RSM) is used to optimize the conditions for the maximum conversion to biodiesel and to understand the significance and interaction of the factors affecting the biodiesel production.The main effects are Methanol/oil molar ratio,Catalyst concentration(wt%),reaction temperature,and reaction time.The optimum conditions derived via RSM are: Methanol/oil molar ratio 7.17∶1,Catalyst concentration 1.08%,reaction temperature 46 ℃,and reaction time 66min.Under the optimum conditions,the actual experimental yield is 96.85% which is better than the predicted value of 98.28%.Multiple regression analysis of the experimental data gives the following second-order polynomial equation.