Noble metal encapsulated sulfide catalyst for the production of aviation biofuel from the hydroprocessing of non-edible oils

Abstract

Encapsulation of noble metals inside the zeolite cage has attracted much attention in the area of catalysis due to unique properties, i.e., shape selectivity, higher activity, and product yield. In the combined work, encapsulated Platinum (Pt) inside the sodalite cage combined with sulfided nickel and molybdenum supported on silica-alumina (NiMo(S)/SiO2-Al2O3) is used to improve the catalyst hydrogenation function by providing spillover hydrogen to the nearby active sulfided NiMo sites. Encapsulation ensures the protection of the noble metal sites from poisoning due to the sulfur-containing compounds. They have a higher hydrodynamic diameter than that of the sodalite window cage. Experimental results showed platinum encapsulated sulfided nickel and molybdenum supported on silica-alumina (Pt@SOD-NiMo(S)-SiO2-Al2O3) had a substantial effect on the product composition, yield, and hydrogen consumption compared with the conventional NiMo(S)/SiO2-Al2O3 catalyst for the hydroconversion reaction of jatropha oil to produce carbon–neutral green fuels. Sustainable aviation fuel with lower aromatics and naphthene content (<1%) was produced over the bi-functional Pt encapsulated Ni-Mo(S)/SiO2-Al2O3 catalysts in the reaction temperature range of 380–420 °C. Aromatics and naphthalene obtained in the aviation range product were as much as 15 times lower than the conventional NiMo(S)/SiO2-Al2O3 catalyst. The Pt@SOD-NiMo(S)-SiO2-Al2O3 catalyst showed stable activity for >600 h of the run, whereas state-of-the-art reported catalyst Pt@SOD-NiMo(S)-ZSM-5 had limitations in terms of catalyst life (stable activity only for 350 h).