Can Mesoporous TiO2-Al2O3-Supported NiMoS OR CoMoS Effectively Perform in Ultra-Deep Desulfurization of Gas Oil?

Abstract

Waste aluminum foil was used for preparation of mesoporous TiO₂-Al₂O₃ using starch as a textural modifier. The catalytic species, Mo and Ni or Co were loaded onto the mesoporous support, following incipient wetness sequential impregnation. To gain an insight into the pore dimensions effect, Ni and Mo species with the same mass ratio were loaded onto the TiO₂-Al₂O₃, prepared from analytical grade chemicals without templating. TPR spectra, TEM images and BET analysis showed how the promoter (Ni or Co), TiO₂ and the template (starch) affect the ease of reduction of Mo species, the morphology of the active MoS₂ phase and the pore dimensions of the catalysts. The catalysts were employed in hydro-desulfurization process of gas oil using a fixed bed down flow microreactor at varying operating conditions, viz., temperature (320–400°C), Liquid hourly space velocity (0.5–4 h^–1), H₂/oil ratio of 450 v/v, and 6 MPa operating pressure. The results showed that the promotion effect prevails over the textural effect, where Ni promoted catalyst (with lower surface parameters) exhibits higher activity than Co promoted one. The dual layer catalytic bed system achieved the sulfur level less than 10 ppm.