The Effect of Boron on the Activity of Hydrotreating Co-Mo/Al2O3 Catalyst

Abstract

A series of aluminum borate with various boria content were prepared. These materials were used as the supports of Co-Mo catalysts. They were characterized with respect to surface area, pore volume, and pore size distribution. The temperature programmed reduction method was used to monitor molybdenum oxide-support interaction. The results showed that the addition of boria concentration (2, 4, and 6 wt%) decreases the reducibility of the catalyst, reduction peak increase with increasing B2O3 content. Hydrodesulfurization of atmospheric gas oil was carried out over these presulfided catalysts in a bench-scale cata-test unit at 320–360°C and LHSV from 1 to 3 h−1. Hydrogen pressure and H2/HC feed ratio were kept constant at 4 MPa and 300 l/l, respectively. All Co-Mo-/AB catalysts are much more active than the conventional Co-Mo/Al2O3 catalyst on hydrodesulfurization reactions. The dispersion of the active sulfide phase of Co-Mo/Al2O3 catalyst is increased by the incorporation of adequate boria content. An optimum B2O3 content, which gives the highest activity, was found in the vicinity of 4 wt%.