Optimization of Biodiesel Production from African Crude Palm Oil (Elaeis guineensis Jacq) with High Concentration of Free Fatty Acids by a Two-Step Transesterification Process

In this study, African crude palm olein (CPO) was used to synthesize biodiesel. The objective was to determine the optimal reaction conditions for the methanolysis of olein. The used CPO had a 5.72% concentration of free fatty acids (FFA); thus, the production of biodiesel was carried out in two stages: 1) esterification using sulfuric acid and 2) transesterification using sodium methoxide. In order to optimize the yield of biodiesel during the transesterification process, a central rotatable design and the response surface methodology were used. The studied variables were: catalyst loading, reaction time and reaction temperature. The analysis of variance showed that the variables with significant effect were the catalyst loading, reaction temperature and reaction time; as well as the catalyst loading*reaction temperature and catalyst loading*reaction time. Results indicate that the optimal reaction conditions during transesterification are: 0.65% catalyst loading (wt/wtaceite), reaction time of 135 min and a reaction temperature of 56°C. The optimal reaction conditions during esterification are: 2.5% weight of catalyst, reaction time of 150 min and a reaction temperature of 64.5°C. Under these conditions, a 90% yield of biodiesel was obtained.