Investigation On The Hydrodesulrization Performance Of The Mo-REHY Catalyst

In this paper, the Mo-REHY,CoMo-REHY and NiMo-REHY catalysts were prepared by isometric impregnation methods, and characterized by TG-DSC,XRD,NH3-TPD and BET methods. The hydrodesulfulrization (HDS) performance of the catalysts was evaluated by using 0.6wt% dibenzothiophene (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 320℃by the course of (NH4)6Mo7O24·4H2O→(NH4)4Mo5O17→(NH4)2Mo4O13→(NH4)2Mo22O67→>MoO3.And the decomposition product MoO3 was sublimated when the temperature was higher than 680℃.Compared with REHY zeolite, the sublimation of MoO3 was not observed in the TG curve of (NH4)6Mo7O24·4H2O+REHY.The crystalline phase peak attributable to REHY keeped intact of the Mo-REHY,CoMo-REHY and NiMo-REHY catalysts. The active component Mo of Mo-REHY catalysts was into REHY bulk, causing the acid and BET surface reduced. But the Ni promoter enlarged the BET surface of Mo-REHY catalyst,while the Co promoter made the BET surface decreased.The DBT HDS conversion of the sulfided catalyst of the Mo-REHY with 5.0wt% Mo prepared at 520℃reached to 16.46%,43.21% and 70.43% under the reaction conditions of 270℃,290℃and 310℃,4.0MPa and space velocity 40h-1,and increased by 1.56,6.47 and 2.83 percentage points compared to 520℃temperature prepared at. Increasing the calcine temperature, the DBT HDS conversion of Mo-REHY catalysts was roughly equal. It can be seen that the suitable calcine temperature of preparing the Mo-REHY catalyst was 520℃in this paper. With the increasing of the calcine time, The DBT HDS conversion of Mo-REHY catalyst increased.With 8.0wt% Mo, Mo-REHY catalyst calcined at 520℃for 12 hours performanced higher HDS activity. It was found that Ni or Co promoters improved the DBT HDS activity of Mo-REHY, and Ni was better than Co in promoting catalytic performance of the catalyst. Besides, the pathway of DBT HDS reaction on Mo/γ-Al2O3 was based on the way of desulfurization,but on the way of hydrogenation on the Mo-REHY,CoMo-REHY and NiMo-REHY catalysts.