Preparation and characterization of hydrotreating catalysts I . Preparation of MoNiP/Al2O3 and effect of promoters

Based on the characterization of a series of commercial gamma -Al2O3, a new type of gamma -Al2O3 has been developed. The gamma -Al2O3 has larger CDA f or active metal (such as Mo or W) from 5.04 to 5.82 mu mol/m(2), and also h as larger pore diameter, concentrated pore volume distribution and higher m echanical strength, so it can be used as a good support for hydrotreating c atalysts. The MoNiP/Al2O3 catalyst has been prepared and the effect of prom oters Ni and P was studied by means of PASCA in conjunction with XPS, DRS, TPR and microreaction-chromatography. The results showed that the promoter Ni combined with 2 types of stronger metal-support interaction centers, res ulting in formation of NiMoO4-like compound. The optimum Ni content is w (N iO) = 4.0 % (n(Ni)/n(Mo) = 0.323) in the catalyst. The promoter P plays a r ole in inhibiting the formation of tetrahedral structure Mo[T] and in promo ting the formation of octahedral structure Mo[O]. The optimum P content is w(P) = 2.6 % (n(P)/n(Mo) = 0.084) in the catalyst.