Study On Preparation Of Biodiesel Using Solid Base As Transesterification Catalyst

Biodiesel,prepared by transesterification of natural oil with alcohols,is an environmental friendly alternative fuel. In traditional homogeneous acid/base catalyzing process the separation of transesterification products with used catalyst is very difficult. Discharge of waste catalyst induces environmental problems. Using heterogeneous base catalyst may avoid the problems of catalytic transesterification reactions and improve the purity of products, it is meaningful for both the production and application of biodiesel.In this work, a series of supported ZrO2 solid base catalysts were prepared. Effects of supporter oxides and preparing procedure on the catalytic activities were systematically investigated. Impregnating method was chosen to support KOH, KNO3, KCl, KF, K2CO3 onto ZrO2 supporter. After screening of the catalyst, we found the solid base KOH/ ZrO2 showed the best catalytic activity. Then influence of the preparation conditions for KOH/ ZrO2 solid base on its catalytic activity was studied, and the suitable technological conditions for preparing KOH/ ZrO2 solid base were determined: the optimal loading amount of KOH was 5mmol/g, and the roasting temperature of catalyst was 550℃. The characterization of KOH/ ZrO2 sample was conducted with IR spectroscopy on Nicolet 380 spectrometer.The influences of transesterification reaction conditions were discussed and the optimized parameters were determined: the methanol/oil mole ratio at 8:1, the catalyst dosage at 5%(based on soybean oil), reaction temperature 65℃, and reaction time 4h. The yield of biodiesel reached to 91.67% under the optimum transesterification conditions.Key properties of the biodiesel produced by this process have been determined and meet the criteria of DIN V 51606.