Investigation On The Hydrodesulrization Performance Of The MoO_X-LaHY Catalyst

The future specification more and more drastic for Sulfur-containing in diesel fuels is leading refiners to develop novel catalysts for deep desulfurization. The MoOx-LaHY catalysts were synthesized by solid-state reaction, and characterized by TG-DSC,XRD,NH3-TPD,BET. The hydrodesulfulrization (HDS) performance of the MoOx-LaHY catalysts was evaluated by using DBT/decane as the model reactant in the high-pressure micro-reactor.The TG-DSC results indicated that (NH4)6Mo7O24·4H2O decomposed to the MoO3 at 314℃by the pathway of losing water molecules and ammonia, and then was sublimated completely with the temperature increasing after 771℃. The LaHY zeolite began to lose crystal water at 614℃and destroied the framework at 1010℃. Compared with LaHY zeolite, the sublimation of MoO3 was not observed in the TG curve of (NH4)6Mo7O24·4H2O+LaHY. As the upper loading of Mo being 5wt%, the single-phase complex nMoOx.LaHY was prepared at 520℃by using solid-state reaction with the mixture of 0 and LaHY under air atmosphere, which the bulk Mo was 3.14 wt%. The single-phase complex nMoOx·LaHY was easy synthesized under reduction atmosphere and steam atmosphere than that of air atmosphere at the same experimental conditions. MoOx, which possessing positively charged clusters, could cover the acid centers and decrease the acidity of nMoOx·LaHY. The BET surface area of nMoOx·LaHY decreased significantly by solid-state reaction under hydrothermal conditions.The hydrodesulfurization(HDS) conversion of dibenzothiophene over MoOx-LaHY catalyst (Mo loading being 5wt%), prepared at 520℃by using solid-state reaction with the mixture of (NH4)6Mo7O24.4H2O and LaHY in reduction atmosphere, reached to 94.37% and 96.86% under the reaction conditions of 4.0MPa, space velocity 8h-1,300℃and 330℃, which was 30 percentage and 10 percentage higher than that of MoO3/Al2O3 (Mo loading being 20wt%), respectively. It was found that Ni and Co promoters could significantly improve the DBT HDS activity of MoOx-LaHY, and Ni was better than the corresponding Co in promoting catalytic performance of the catalyst.