Bimetallic CoMo and trimetallic CoMoW catalyst supported on γ-Al2O3 for efficient naphtha hydrodesulfurization

Bimetallic Co5Mo15 of 5 wt% Cobalt as a promoter and 15 wt% Molybdenum as an active metal and trimetallic Co5Mo15-xWx (x = 1, 3, 5 wt%) heterogeneous catalysts supported on gamma alumina (gamma-Al2O3) were synthesized by an incipient wetness co-impregnation process. The structural and the physicochemical characteristics of the prepared bi- and tri-metallic catalysts were evaluated by the XRD, SEM, BET and BJH. The role of third W active metal on the catalytic activity was determined through a hydrodesulfurization (HDS) reaction of naphtha at four different reaction temperatures (250, 275, 300, 325 degrees C) and four liquid hourly space velocities, LHSV (3, 4, 5, 6 h(-1)) under constant 1.5 MPa H-2 pressure. The trimetallic CoMoW5 catalyst exhibited the maximal HDS efficiency at 325 degrees C and 3 h(-1) liquid flow of 88% sulfur removed compared to the CoMo catalyst. This was ascribed for the role of the highly dispersed active W metal and presence of the sulfided CoMoWS and CoWS sites on the alumina surface that leads to increase the surface area and the porous structure, and enhancing the metal/sulfur bond.

Automated summary

Bimetallic and trimetallic catalysts, with cobalt and molybdenum as active metals, were synthesized on gamma alumina support. The trimetallic catalyst, CoMoW5, showed the highest desulfurization efficiency at 325 degrees C and 3 h(-1) liquid flow.