Biodiesel synthesis using heterogeneous catalyst in a packed-microchannel

The goal of this research was to investigate the using of a packed-microchannel reactor to continuously synthesize biodiesel in a heterogeneous catalyst system. Calcium oxide (CaO) was used as a catalyst and was activated with methanol to enhance the catalytic performance for the transesterification reaction of palm oil. The synthesized activated CaO was characterized and confirmed by using X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET), Hammett indicator and field emission scanning electron microscope (FE-SEM) techniques. The results indicated that the catalyst with higher surface area and total basicity was provided after activation and showed the higher catalytic activity compared to that of as-received CaO. The main important factors affecting the biodiesel synthesis were investigated and the optimal reaction conditions based on the purity of biodiesel were also determined. Complete reaction with the purity of biodiesel of 99% was achieved despite the short residence time used in this research. The optimal reaction conditions within the investigated parameter region were 65 °C, methanol-to-oil molar ratio of 24:1, and residence time of 8.9 min. The catalyst sustained high %FAME over 24 h of continuous operation. Furthermore, high fuel quality and superior productivity performance could be achieved via the packed-microchannel reactor.