Biojet fuel production via deoxygenation of crude palm kernel oil using Pt/C as catalyst in a continuous fixed bed reactor

Abstract

• The production of biojet fuel with low content of oxygenated compounds from crude palm kernel oil was achieved. • The use of continuous fixed-bed reactor provided hight yield and high productivity of biojet fuel. • The cold flow properties of biojet fuel was improved by using HZSM-5 catalyst. This work focused on the conversion of crude palm kernel oil (CPKO) to biojet fuel via deoxygenation reaction in a fixed bed reactor. The catalyst was Pt supported on activated carbon (Pt/C). The investigation involved the effects of various operating parameters such as reaction temperature (350–420 °C), pressure (250 and 500 psi), flow rate of CPKO (0.02 and 0.04 mL/min), flow rate of hydrogen (17.5, 35.0, and 70.0 mL/min), and the amount of catalyst (0.05 and 0.07 g) on the reaction performance and the fuel properties of product. The biojet yield of 58.29%, with the major content of linear alkane in the range of jet fuel (nC8-nC16) of 27.68% and the productivity of 9.32 g product/g catalyst·h were achieved at the optimal operating conditions (420 °C, 500 psi, CPKO flow rate at 0.02 mL/min, hydrogen flow rate at 17.50 mL/min (H 2 -to-CPKO molar ratio of 28.02), and 0.07 g of Pt/C catalyst). The oxygen content was reduced from 18.83% (in CPKO) to 14.96% (in the product). To improve the freezing point of biojet fuel via cracking and aromatization, the catalyst bed was modified by adding HZSM-5 as a catalyst bed adjacent to the bed of Pt/C. The freezing point of product was significantly lowered by 30 °C.