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The influences of impurities and oxidation evolution of waste cooking oil on the preparation of bio‐jet fuel via hydroconversion were studied. The hydrogenation active sites and acid sites were covered by heavy metals, sulfides, and basic nitrogen compounds, resulting in the increase of selectivity for bio‐jet fuel by decreasing the selectivity of diesel, aromatics, and iso‐alkanes. The effects of impurities, oxidation on the reaction pathway, and product distribution became more distinct with higher catalyst acidity. The evolution and variation of naphthalene, indan, and phenanthrene obtained from cyclic fatty acids influenced the properties of fuel or evoked the catalyst deactivation. This work will help to design new catalysts for selective conversion of waste cooking oil into bio‐jet fuel. [ABSTRACT FROM AUTHOR]

Abstract: 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 °C and a high H2/oil ratio would decrease the yield of jet fuel. This catalyst showed excellent stability for the hydroconversion of WCO to hydrocarbons. [ABSTRACT FROM AUTHOR]