Waste cooking oil to jet-diesel fuel range using 2-propanol via catalytic transfer hydrogenation reactions

Abstract

2-propanol (99.9 wt%) was used as an H-donor to produce jet/diesel-fuel range from waste cooking oil (WCO) over a fixed bed of granular activated carbon in a continuous flow reactor. The reactions were carried out at 2 bar and at a temperature range of 300–400 °C with weight hourly space velocity (WHSV) of 6.7 h−1. An optimum yield of 72% liquid hydrocarbon (LHC) at 380 °C was observed. The LHC contained 32% alkanes, 16% aromatics and 37% alkenes at the optimum temperature. Using 2-propanol as an in situ hydrogen source will potentially reduce the volume ratio of hydrogen source to oil (0.4 L 2-propanol/L WCO) compared to what is reported in the literature for conventional use of hydrogen gas at high pressures. Evaluation of reaction kinetics revealed that the rate of catalytic transfer hydrogenation of WCO is second order with an activation energy of 53 kJ/mol. With 10 hours of continuous catalytic transfer hydrogenation (CTH) of WCO, the catalyst maintained its catalytic activity despite the inherent coke formation.