Optimization of a two-step process for biodiesel production from Jatropha curcas crude oil

摘要

In the present work, the process of synthesis of methyl esters from Jatropha curcas crude oil as an alternative vegetable oil, using a two-step catalyzed process is shown. In the first step, sulfuric acid was used as a catalyst for the esterification reaction of free fatty acid (FFA) and methanol in order to reduce the FFA content to ～0.2%. In the second step, the product from the first step was further reacted with methanol using potassium metoxide as a catalyst. The two-step processes have been developed and optimized by application of the factorial design and response surface methodology. The optimum conditions for biodiesel production were obtained when using methanol to FFA contents of Jatropha crude oil molar ratio (MR) of 20:1, 5 wt% of sulfuric acid, at 60°C with a reaction time of 60 min in the first step, followed by using an MR of methanol to product from the first step of 6:1, 0.95 wt% of KOCH₃, at 45°C with a reaction time of 60 min in the second step. The percentage of methyl ester in the obtained product was more than 98%. The model has been found to describe the experimental range studied adequately and allows us to scale-up the process. In addition, the fuel properties of the produced biodiesel were in the acceptable ranges according to EN14214 European biodiesel standards.