Atmospheric hydrotreatment of used palm cooking oil over nickel-dispersed phosphated zirconia as highly stable nano-catalyst for bio-jet fuel production

Increasing carbon dioxide gas emissions due to the high demand for the aviation industry and the depletion of fossil fuel sources are serious issues that require researchers to develop bio-jet fuel from vegetable oils to achieve carbon neutrality. In this study, novel Ni/PO4–ZrO2 nano-catalysts have been successfully synthesized by spray impregnation and tested for their performance in converting used palm cooking oil into bio-jet fuel through an atmospheric hydrotreatment process at 350–550 °C. Different nickel-loading amounts create other characters for each nano-catalyst, and adding as much as 1 % fabricates the Ni 1/PO4–ZrO2 nano-catalyst with the best acidity. Compared with wet impregnation, spray impregnation offers advantages in terms of its superior catalytic performance and economic values for industrial upscale. Hydrotreatment of used palm cooking oil with an H2 gas flow rate of 20 mL/min for 2 h using the Ni 1/PO4–ZrO2 nano-catalyst with an optimum catalyst-to-feed ratio of 1:100 (w/w), the resulting liquid product and total bio-jet fuel yield were 60.60 % and 54.71 %, respectively. After this nano-catalyst was used repeatedly for five consecutive runs, it still maintained remarkable performance, giving a bio-jet fuel yield of 41.08 % (after the 5th run) and 46.26 % (after regeneration). Blending our bio-jet fuel with commercial jet fuel at a 2.4 % (v/v) ratio satisfactorily did not compromise commercial jet fuel's freezing point.