DIFFUSION AND CATALYTIC ACTIVITY STUDIES ON RESID-DEACTIVATED HDS CATALYSTS

Three different pore size CoMo/Al//2O//3 catalysts, which had been deactivated to the same extent during bench-scale tests with an atmospheric resid, were examined for coke and metal deposits, diffusivity, and intrinsic activity for hydrodesulfurization, hydrogenation, and hydrodenitrogenation using model compounds. The aged catalysts had very low effective diffusivities and lower intrinsic activities than the fresh catalysts. Both metals and coke deposits were responsible for lowering diffusivity, but activity reduction appears to be predominantly due to metal deposits.