Simultaneous reaction and separation technologies for biodiesel production derived from alternative feedstocks

Abstract

This research focused on the production of biodiesel using hybridized reactive distillation (hybridized RD) and centrifugal contractor reactor (CCR) from waste cooking oil (WCO) to reduce the operating cost. However, WCO contains some water which can cause saponification. The study showed that using two heat exchangers with hybridized RD is a simple method for water removal but it required the highest energy and cost (1.63 $/kg biodiesel). The extended spacing stage for water removal required a new hybridized RD construction with additional spacing stages. This method can handle and require less energy, resulting in lower cost (1.07 $/kg biodiesel). The integration of pervaporation unit was found to be the best option offering in terms of water removal and methanol recovery, resulting in the lowest cost (1.04 $/kg biodiesel). Additionally, CCR was designed for heterogeneously catalyzed biodiesel production. The optimal conditions were a methanol-to-oil ratio of 12:1, CaO catalyst loading of 13 wt%, and rotating speed of 1,000 rpm at 60°C, based on the center composite design and response surface methodology, offering the biodiesel yield of 95.01 and 81.82 % for refined palm oil and WCO feedstocks, respectively. The CaO catalyzed transesterification in the CCR was found to be a pseudo-second-order reaction with an activation energy and pre-exponential factor of 26.53 kJ/mol and 98.5 min-1, respectively.