Abstract
To clarify the effect of sulfur compound addition on catalytic activity and catalyst deactivation, hydrodesulfurization (HDS) of coker gas oil (CGO) was carried out over demetallation catalysts, metal tolerant desulfurization catalyst and desulfurization catalysts. The initial HDS constant and catalyst life were slightly improved by the addition of 1000 ppm of dimethyldisulfide (DMDS), probably by the prevention of coking on the catalyst surface. The CH3S radical formed via thermal decomposition was important in the suppression of recombination of heavy hydrocarbon radicals which results in coke or coke precursor formation. The addition of small amounts of sulfur compounds to the CGO is expected to reduce coke formation during the early stages of HDS.
