The Effect of Boron on the Activity of Hydrotreating Co-Mo/Al₂O₃Catalyst

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 B 2 O 3 content. Hydrodesulfurization of atmospheric gas oil was carried out over these presulfided catalysts in a bench-scale cata-test unit at 320-360 ı C and LHSV from 1 to 3 h 1 . Hydrogen pressure and H 2 /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/Al 2 O 3 catalyst on hydrodesulfurization reactions. The dispersion of the active sulfide phase of Co-Mo/Al 2 O 3 catalyst is increased by the incorporation of adequate boria content. An optimum B 2 O 3 content, which gives the highest activity, was found in the vicinity of 4 wt%.

Biowax Production from the Hydrotreatment of Refined Palm Oil (RPO)

“…The lower conversion obtained with the Reference 2 catalyst could be related to the presence of boron, which provokes changes to the surface and acid properties of the catalyst. These modifications promote the esterification reactions at these process conditions [44,45], and, as it was mentioned before, these reactions are slow, and therefore a minor triglycerides amount are converted at the same time on stream. The previous is in concordance with the percentage of waxy esters present in the waxes obtained, which for the Reference 1 catalyst, was 23.23%wt and for the catalyst with Boron was 28.9%wt.…”

“…Additionally, as seen in Figure 9, an increase in the concentration of light compounds at lower LHSV was observed, accordingly with the carbon numbers distribution from C5 to C12 in the biowax obtained. These catalytic hydrocracking reactions are mainly promoted by acid sites present in the solid; in the Reference 1 catalyst (NiMo/Al 2 O 3 ), this is attributed to the presence of phosphorus as a dopant in the support, which is commonly used to improve metal dispersion without significantly affecting its hydrogenating activity and reducing deactivation by coke formation during hydrotreating [44].…”