Deactivation and characterization of hydrotreating NiMo/Al2O3 catalyst coked by anthracene.

Sulfided NiMo/Al2O3 catalyst was coked in an autoclave reactor at 440 degrees C with pur anthracene to give catalysts containing 1-20 wt% C. After Toluene extraction, physical properties and catalytic activities using model compounds (phenanthrene, 4,6-dimethyldibenzothiophene and 1,2,3,4-tetrahydroquinoline) for hydrogenation (HYD), hydrodesulfurization (HDS) and hydrodenitrogenation (HDN) were measured on the coked catalysts. All the physical properties (BET, pore volume) decreased when the coke content increased, which corresponds to a partial blockage of the catalyst pores. All the catalytic activities in the various hydrotreating reactions (HYD, HDN and HDS) decreased when the coke content increased. An order of deactivation was able to be established : HDN > HDS approximate to HYD.