On the effect of reaction conditions on liquid phase sulfiding of a NiMo HDS catalyst

Various experimental tests were conducted in a fixed-bed pilot plant in order to study the liquid phase sulfiding of a NiMo commercial catalyst. Four sulfiding feeds were employed in the present work: SRGO, SRGO + 1 wt.% sulfur DMDS, HDS-SRGO + 1 wt.% sulfur DMDS, and HDS-SRGO + 1.7 wt.% sulfur DMDS. Three sulfiding temperatures were evaluated: 290, 320, and 350°C. Drying and soaking of the catalyst were carried out before presulfiding. Each sulfided catalyst was evaluated in the hydrotreating of SRGO at the following conditions: 54 kg/cm² pressure, 2.0 h^-1 LHSV, 2000 ft³/bbl H₂-to-oil ratio, and temperature of 340-380°C. SRGO + 1 wt.% sulfur DMDS was the best sulfiding feed. The catalyst sulfided at high temperature exhibited better activity. It was found that about 50% of the carbon on the catalyst after reaction is deposited during sulfiding step.