Development of highly active Co-Mo catalysts with phosphorus and citric acid for ultra-deep desulfurization of diesel fractions (Part 1) preparation and performance of catalysts

HY-Al2O3-supported Co-Mo catalysts were prepared with citric acid and phosphorus for the hydrodesulfurization of diesel fractions. The HDS activity was measured with straight-run light gas oil feedstocks under actual hydrotreating conditions. CoMoP/HY-Al2O3 catalyst had three times higher HDS activity compared with the conventional CoMoP/Al2O3 catalyst. The long-term stability test of ultra-deep HDS of the developed catalyst was carried out in a pilot plant under conditions maintaining 10 ppm sulfur content in the product. This catalyst enables deep HDS of diesel fuel and shows no significant deactivation. Commercial operation with the developed catalyst has successfully demonstrated high performance. The developed catalyst has super high activity, which enables < 10 ppm sulfur content in products in a commercial hydrotreater designed to produce 500 ppm sulfur diesel fuels. The reaction kinetics of the HDS over the developed catalyst in the diesel hydrotreater fit 1.2-order kinetics. The apparent activation energy calculated from the Arrhenius plots is 100 kJ/mol.