Hydroconversion of Waste Cooking Oil into Bio-Jet Fuel over a Hierarchical NiMo/USY@Al-SBA-15 Zeolite

The direct conversion of waste cooking oil (WCO) into bio-jet fuel was investigated over a core-shell hierarchical USY@Al-SBA-15 zeolite-supported NiMo catalyst. The core-shell structure showed better acid and pore size distributions. The synergetic effect of the core-shell micropore and mesopore structure significantly contributed to enhancing the selectivity for the jet fuel (C9-15 hydrocarbons) from 9.3% over NiMo/USY up to 35.7% over NiMo/USY@Al-SBA-15, with high isomerization (iso-/n-paraffins ratio = 2.7) and moderate aromatic fraction (18.7%). The decarboxylation reaction was selectively enhanced. Optimal selectivity for jet fuel (39.7%) was obtained at 380 degrees C and a high H-2/oil ratio would decrease the yield of jet fuel. This catalyst showed excellent stability for the hydroconversion of WCO to hydrocarbons.