HDS And HDN Reactivities Research On Bulk MoS₂ Modified By Nickel

In resent years, the environmental protection laws and regulations are stricter, however, the petroleum quality drops gradually, sulfur content in crude oil is rising. Therefore, developing the more efficient catalyst for deep hydrodesulfurization is still an important point of catalysis research. As the most widely used catalyst for industrial application, the traditional molybdenum sulfide catalyst also needs innovation.Bulk molybdenum disulfide catalyst (MoS2) was prepared from ammonium tetrathiomolybdate (ATM) as a precursor; Ni-Mo-S catalyst was also synthesized from ammonium tetrathiomolybdate while the nickel was used as a promoter. The hydrodesulfurization (HDS) performances of these two catalysts were studied by using a model fuel of decalin solution containing 0.8% dibenzothiophene (DBT), the hydrodenitrogeneration (HDN) performances of them were also studied by using a model fuel of decalin solution containing 0.8% quinoline (Q), and so were the influences of those two reactions.The reasults indicated that the HDS reaction over MoS2 mainly proceeded through hydrogenation (HYD) pathway and the activity was restrained by nitrogen-containing compound quinoline obviously, the DBT conversion reduces about 50%. On the contrary, the HDN activity was promoted in the presence of DBT, the Q conversion was doubled.The HDS and HDN activities both increase by the introduction of nickel, and the reaction networks do not change. The DBT HDS conversion over Ni-Mo-S increased about 35% while the Q HDN conversion was doubled.From the XRD patterns and the results of nitrogen adsorption, we found that the specific surface area was increased by the introduction of nickel, the grain size reduced at the same time, these aspects were considered as the reasons for the improvement of HDS and HDN activities. The inhibition of HDS activity over Ni-Mo-S is weaker than it over MoS2, this indicates that the introduction of nickel increases the nitrogen resistance of molybdenum disulfide.The results of the HDN reaction on these two bulk catalysts also proved that propyl benzene (PB) as the end product of HDN reaction can be produced though the decahydroquinoline pathway of HDN reaction.