Effects Of Catalyst Variation On Biodiesel Yield

Abstract

The type, purity and amount of catalyst used affect the conversion efficiency of the transesterification process of converting oil to biodiesel. In this study, the effect of alkali and acid catalysts variation was examined on biodiesel yield. Sodium hydroxide at different concentration of 0.6-1.6% to unused oil was used as a catalyst for transesesterifying unused oil to biodiesel. The optimum biodiesel yield was achieved using 1.4 wt. % of NaOH to oil weight, which produced an 88.0% yield of transparent methyl ester. Similarly, HCl was used at different concentration (0.8-1.8% to oil weight) to catalyse the transesterification process of used oil to biodiesel because the performance of the acid catalyst (HCl) is not strongly affected by the free fatty acid. Hydrochloric acid at a concentration of 1.6% to the oil weight brings about optimum yield of biodiesel (60%) from used frying oil. The biodiesel yield gradually increases as the concentration of the catalyst increases up to 1.6% to the oil weight, further increase in the concentration of the catalyst beyond this point results in the formation of soap and gel which significantly reduces the biodiesel yield.