Catalyst for Biodiesel: An Overview of Catalysts Used in Biodiesel Production

Background

The biodiesel is produced from vegetable oils or fats by a chemical process called as transesterification. In transesterification reaction, vegetable oil or animal fat reacts with alcohol such as methanol or ethanol, in the presence of a catalyst and the products of the reaction is biodiesel and glycerin. The non-edible oils are believed to be one of the major feedstock for the production of biodiesel. In transesterification reaction, oil or fat reacts with three moles of light alcohol to give three moles of biodiesel and one mole of glycerol. The transesterification is a reversible reaction and hence excess alcohol is added to shift the reaction to the product side. The crude biodiesel is treated to remove methanol and catalyst, and refined to fulfill the biodiesel standard specifications (Stojković, et al., 2014). The treatment process should be evaluated with respect to its treatment efficiency and operational requirements. Hence an integration treatment involving acidification, coagulation/flocculation and a biological process is the best choice. The reuse of the pretreated wastewater is also an interesting alternative (Veljković, et al., 2014).