Kinetics of Biodiesel Production From Non-Edible Vegetable Oils

A comparative study of the kinetics of production of biodiesel from the transesterification of three non-edible vegetable oils is undertaken. A three step mechanism  was used to model  the kinetics in the case of Pongamia oil which was found to be  a mixture tri-, di- and monoglycerides. On the other hand, an one-step model was sufficient for Jatropha and Mahua oils both of which contained largely triglycerides. The rate of transesterification at comparable temperatures and catalyst concentrations was found to be the highest for Jatropha oil followed by Mahua and then Pongamia oil.  The effect of cosolvent on the rate of transesterification was noticeably higher for Mahua oil than for the other two oils but still much lower than that reported in the literature for both soybean and canola oil. Kinetics of transesterification of oils to yield biodiesel thus depends on the composition of the oil under consideration. Therefore studies are under way to examine the fine structure of  the triglycerides contained in the various oils and establish a correlation with the kinetics of transesterification.