Process simulation and energy optimization of the enzyme-catalyzed biodiesel production

Biodiesel, as an alternative and renewable fuel, has been studied and developed in recent years. In the present paper, a continuous enzyme-catalyzed biodiesel pilot plant using waste cooking oil, with production capacity of 6482 ton/yr, was simulated by Aspen Plus. Detailed operating conditions and equipment designs were obtained. Five reactions were applied to represent the transesterification of the biodiesel production. The simulation results were in good agreement with the real data. Based on the simulation of the original process, five optimization processes, were proposed focusing on energy saving and methanol recovery. Pinch technology was also used to develop heat exchange networks. Throughout the different optimizations, the quality of biodiesel was still kept at a high purity (>98.5%).

► The production of biodiesel from waste oils is gaining industrial interest. ► A biodiesel plant, using a novel enzyme-catalyzed production process, is in operation in Shanghai (China). ► The initial process is highly energy-intensive and consumes significant amounts of methanol for the trans-esterification. ► Aspen simulation was used to optimize the process. Different strategies were investigated, and pinch technology applied. ► As a result, modified processes were proposed, with major energy savings, and a significant methanol recovery and re-use.