Evaluation of a hollow fiber membrane contactor reactor for reactive extraction in biodiesel production

A polypropylene hollow fiber membrane contactor reactor (HF-MCR) was used to evaluate the performance of a reactive extraction process for biodiesel production. The process involved the transesterification of soybean oil with methanol, catalyzed by sodium hydroxide. The experimental methodology assessed the impact of oil flow rate and methanol/oil molar ratio on the biodiesel (FAME) production rate, triglyceride reaction rate, and glycerin concentration in the final biodiesel product. The results demonstrated that, by employing a countercurrent configuration, is possible to extract the glycerin from the biodiesel-rich phase with methanol, achieving both the reaction and the separation stages in the same equipment. The best results were obtained at a methanol/ oil molar ratio of 4:1 and an oil flow rate of 0.4 L h-1, leading to a triglyceride conversion rate of 0.14 mol h-1 and a FAME production rate of 0.24 mol h-1, equivalent to 34 % conversion and 56 % yield, respectively. The final biodiesel product showed a low concentration of glycerin, measuring only 0.06 % wt. This investigation highlights the potential of employing membrane contactors technology for the biodiesel production process, reducing the processing time by eliminating the biodiesel/glycerol separation stage, and therefore bringing down the load of downstream purification operations.