HYDRODESULFURIZATION REACTIONS OF ATMOSPHERIC GAS OIL OVER COMO ALUMINA-ALUMINUM BORATE CATALYSTS

A precipitation technique at constant pH value was used to prepare a s eries of alumina-aluminum borates (AABs) with various Al/B atomic rati os. These materials were used as the supports of Co-Mo catalysts. Hydr odesulfurization (HDS) of Kuwait atmospheric gas (AGO) oil was carried out over these presulfided catalysts in a bench-scale trickle bed rea ctor at 400 psi and 340-degrees-C. All CoMo/AAB catalysts are much mor e active than the conventional CoMo/Al2O3 catalyst on HDS reactions. A correlation exists between the acidity and the HDS activity of the ca talysts. The high activities of the CoMo/AAB catalysts can be rational ized on the presence of boron. On one hand, it can increase the metal dispersions and hydrogenation capabilities. On the other hand, it can enhance the acidities and cracking abilities of the catalysts. The des ulfurization data can be fitted with a pseudo-second-order rate equati on. The activation energy for desulfurization is found to be 26 kcal/m ol.