Recently, researchers have developed heterogeneous catalytic system which involves a continuous flow for biodiesel reaction that neither deactivates nor consumes the catalyst and that minimizes or eliminates the need for multitudinous downstream separation and purification steps. The solid base and solid acid catalyst used in transesterification reaction are shown in Tables 10.3 and 10.4 . Utilization of solid

catalyst is a potential catalyst which is able to offer some relief to biodiesel producers by improving their ability to process alternative cheaper feedstock by promoting a shortened and less expensive manufacturing process (Bournay et al. 2005) .There are three important characteristics of catalyst that have a significant impact on the cost of biodiesel, namely, catalytic activity, catalyst life, and catalyst flexibility (Fig. 10.2) which would greatly influence the efficiency of the catalyst in converting oils into biodiesel.

The newly invented heterogenized technology (Fig. 10.3) in biodiesel production technology shall replace conventional biodiesel production (homogeneous cata­lyzed process) to improve the reaction process and reduce the production cost. With the introduction of heterogeneous catalyst, productions are now easily set up any­where in the nation, and the flexibility of the catalyst towards the feedstock oil low­ers the requirement for feedstock oil compared to previous catalyst used in biodiesel production. The catalyst can now catalyze most type of oils with maintained yield and remain its reusability to an extent which is more superior than most of the other homogeneous catalyst in the market. Biodiesel produced using heterogeneous cata­lyst contains lower ash content, and cleaner burning process makes biodiesel another substitution option to replace petroleum as the fuel for our industries as well as our mass transportation system.

Solid base catalyst