Production of synthetic biofuels from palm oil with simultaneous hydro-deoxygenation and isomerization over re promoted Ni/SAPO-11 catalyst

Abstract

Currently, vegetable oils have been generally used as a starting feedstock for biofuel production due to their low functionalization degree and simple chemical structure compared with lignocellulosic biomass. In this work, a simultaneous hydro-deoxygenation and isomerization of palm oil into synthetic biofuels over Re promoted Ni on SAPO-11 catalyst was investigated in a high-pressure trickle-bed reactor. The XRD and XANES analysis confirmed the formation of metallic Ni and Re with small amount of NiO, ReO3, and NH4ReO4 after reduction. The distinguished acid sites by Pyridine DRIFTS confirmed the increase in the Lewis acid sites for the bimetallic NiRe catalyst. As for the reaction investigations, the bimetallic NiRe catalyst with a Re to Ni molar ratio of 0.12 exhibited the highest catalytic activity for synthetic biofuels production. Interestingly, the optimal NiRe catalyst gave a 100% triglyceride conversion with 18.2% and 52.1% of jet and diesel yields, respectively with a classification for 46.8% and 23.5% of iso and normal alkanes yields, respectively under investigated conditions (T: 360 ◦C, H2 P: 30 bar, and WHSV: 2 h-1). Thus, it should be remarkably concluded that the addition of Re into Ni species significantly improved iso-alkanes yields with proper performance on the catalyst lifetime due to the promotional effect of Re species via the simultaneous hydro-deoxygenation and isomerization.