(265f) Simultaneous Esterification and Transesterification for Biodiesel Production
Biodiesel, a mixture of fatty acid esters, is obtained from natural oil resources. As it is nontoxic, renewable and beneficial for environmental protection, it is considered as an alternative fuel to traditional petroleum-based fuels. A major barrier to the commercialization of biodiesel is its high feedstock cost, which is primarily related with using refined vegetable oils as raw material during the production process. Using waste oils is one of the economical sources for biodiesel production. However waste oils generally contain some content of free fatty acids (FFA), the current catalytic approach is to use a two-step process to handle oils with high FFA content. In this study, we developed a one-step process based on Pr2O3/ZnO catalysts, which effectively converted crude soybean oil, crude coconut oil, crude palm oil, crude corn oil from DDGs, crude algae oil, waste cooking oil brown grease, crude algae oil and waste fishing oil into FAME. It was found that the acidic groups on catalyst surface played an important role in esterification reaction; and the base groups catalyze transesterification reaction. Catalyst structure was characterized by XRD, XPS, BET, FTIR, SEM, EDS. The bulk phase of Pr2O3/ZnO catalyst was ZnO. Pr is well disbursed in ZnO crystal. In comparision with other ZnO catalysts, Pr increases the surface acid and base sites which promote the conversion of acidic oils into FAME.