Biodiesel Production from High Free Fatty Acid Oils Using a Bifunctional Solid Catalyst

A bifunctional solid catalyst has been utilized for producing biodiesel from high free fatty acid (FFA) oils by simultaneous esterification and transesterification. Simultaneous conversion of FFA and triglycerides (TG) in the oils into fatty acid methyl ester (FAME) by catalytic action has been demonstrated. The effects of various reaction parameters including reaction time, temperature, and molar ratio of methanol to oil on the yields of FAME have been investigated and optimized. Temperature is found to be the dominant factor determining FAME yield among the various parameters examined. Further, the catalyst exhibits stable activity up to 40 consecutive runs with no intervening regeneration steps. Under optimized reaction conditions, about 80% FAME yield is obtained in a one-step process with 50% FFA oil. Catalyst in the pellet shape may be applied in commercial processes. The feasibility of using the catalyst for biodiesel production from low-cost high FFA waste fats has been successfully demonstrated.