Abstract: Effect of reaction conditions on the selective hydrodesulfurization over an industrial CoMo/Al2O3 catalyst was studied in a fixed-bed flow reactor with model feeds containing sulfur and olefin compounds. The experimental results showed that the olefin hydro-saturation could be reduced by the increase of space velocity, H2/oil molar ratio and the sulfiding temperature of catalyst, as well as by the decrease of hydrogen partial pressure, respectively, which resulted in the improvement of hydrodesulfurization selectivity. In addition, with the increase of olefin content in model feeds, the competitive adsorption of olefin molecules and thiophene molecules on the active sites enhanced, which led to the increase of olefin saturation and the decrease of hydrodesulfurization selectivity.

Key words: Cobalt Molybdenum catalyst, selective hydrodesulfurization, olefin, hydrogenation