Improvement in the hydrodesulfurization of dibenzothiophene over supported NiMoW catalysts

Various supported NiMoW sulfided catalysts were synthetized and tested in the hydrodesulfurization (HDS) of dibenzothiophene (DBT). The influence of cetyl trimethyl ammonium bromide (CTAB) on the properties of titania, silica and Si-Ti mixed oxide, prepared by sol-gel and used as supports, was evaluated. The active metals were then sequentially co-impregnated on the carrier. For all catalysts, the Ni/[Ni(MoW)] and Mo/W atomic ratios were kept constant and equal to 0.5 and 1, respectively. In addition, the total metal content was 18 wt% for each sample. All catalysts were characterized by BET, TEM, XRD and UV-Vis. The use of CTAB as a surfactant influences the textural properties of the supports. Among the studied samples, the best catalyst was NiMoW/Si-Ti, which showed a DBT conversion of 94% after 5 h of reaction at 320 degrees C and 5.3 MPa. For comparison, a commercial NiMo/Al2O3 catalyst was used as a reference.