The effects of support and promoter on thiophene hydrodesulfurization and tetralin hydrogenation

The catalyst preparation and the catalyst test were carried out in the same conditions in this paper so as to give a good insight into the effects of the support and promoter on hydrotreating catalysis. The results of thiophene hydrodesulfurization (HDS) and tetralin hydrogenation (HYD) displayed that the activity over the unpromoted catalysts increased with the used support in the order TiO2-Al2O3 > ZrO2 > Al2O3. As for the promoted catalysts, the Ni-promoted catalyst exhibited significantly higher activity than the Co-promoted one, and the ZrO2-supported Mo and W catalysts gave the highest HDS and HYD activity, respectively. Whereas Pt showed no synergy effect but rather additivity of the catalytic properties with Mo and W sulfides. The sequence of sulfidation and introduction of Ni and Co was very important. Using our catalyst preparation method could avoid too early sulfidation of Ni and facilitated the formation of the active Ni-Mo-S phase. This effect was probably similar to that observed in the systems prepared with addition of chelating agent.