Biodiesel production in a rotating packed bed using K/γ-Al₂O₃ solid catalyst

The methanolysis of soybean oil with a K/γ-Al₂O₃ catalyst using a rotating packed bed (RPB) for the production of fatty acid methyl esters (biodiesel) is presented. The RPB, which provides high centrifugal force and has an adjustable rotational speed, was employed as a novel heterogeneously catalyzed transesterification reactor. The methanol-to-oil molar ratio, the catalyst dosage, the rotational speed of the packed-bed rotator, and the reaction temperature were investigated for their effects on the yield of fatty acid methyl esters (Y_FAME) in the RPB. Furthermore, the modified first-order reaction kinetics was employed to study the transesterification reaction rate of the K/γ-Al₂O₃ catalyzed RPB system. In addition, the transesterification performance and durability of the K/γ-Al₂O₃ catalyst with respect to Y_FAME using the RPB system were evaluated, allowing for further comparison with other heterogeneously catalyzed transesterification reactors. Based on the results, the RPB system is considered as a practical, heterogeneously catalyzed transesterification reactor due to its excellent micromixing characteristics.