Biodiesel Production Through Waste Cooking Oil (WCO) Esterification Using Sulfated Alumina as Catalyst

Abstract

Biodiesel produced from waste cooking oil (WCO) with initial free fatty acids (FFA) of 6.67 % through one-stage reaction (transesterification) and two-stage reaction (esterification followed by transesterification) had been studied. The esterification process was catalyzed by solid catalyst of synthesized sulfated alumina and transesterification reaction was catalyzed by NaOH. The objective of this research is to determine the optimum condition of biodiesel production from WCO using sulfated alumina catalysts by esterification reaction and to compare biodiesel yield using homogeneous catalysts of sulfuric acid with a heterogeneous catalyst of sulfated alumina. The results showed that the optimum conditions for esterification reactions using sulfated alumina catalyst is at the volume ratio of methanol/oil of 1.5, the amount catalyst of 1 wt %/v of oil at 1 hour reaction time. With the optimum condition, the maximum conversions of free fatty acid using a sulfuric acid and sulfated alumina catalyst were 90.4 % and 89.97 % respectively. The yield of biodiesel from waste cooking oil by two-stage transesterification process is 86.67 % and one-stage transesterification is 66.67 %.