关键词: 磷化二镍, 催化剂, 加氢脱硫, 柠檬酸, 制备

Abstract: The TiO₂-Al₂O₃ complex support was prepared by sol-gel method. A nickel phosphide catalyst, Ni₂P/TiO₂-Al₂O₃ with citric acid (CA) as chelating agent, was prepared by the impregnation method. The catalysts were characterized by X-ray diffraction (XRD) and N₂-adsorption specific surface area measurements (BET). The effects of calcination temperature of support, calcination temperature of catalyst, reduction temperature, reduction pressure and calcination time of catalyst on catalyst activity for dibenzothiophene (DBT) hydrodesulfurization (HDS) were studied. The result showed that increasing the calcination temperature of support favored dispersion of active species on catalyst surface. The optimal calcination temperature of support was 550℃ because of catalyst sintered by excessive temperature. When reduction temperature was in the reange of 500—550℃, the active phase was mixed phases of Ni₁₂P₅ and Ni₂P. The peak intensities of Ni₁₂P₅ increased with the reduction temperature increasing. At reduction temperature of 700℃, the single Ni₂P phase was observed. The Ni₂P/TiO₂-Al₂O₃ catalyst prepared under a support calcination temperature of 550℃, a catalyst calcination temperature of 500℃, a reduction temperature of 700℃ under atmospheric pressure was found to be optimal. At reaction temperature of 360℃, pressure of 3.0MPa, hydrogen/oil ratio of 500 (V/V), and liquid hourly space velocity of 2.0h^-1, the conversion of dibenzothiophene HDS was 99.5% in 4h.

Key words: nickel phosphide, catalyst, hydrodesulfurization, citric acid, preparation