Deactivation of a nickel-molybdenum/.gamma.-alumina catalyst: influence of coke on the hydroprocessing activity

摘要: This paper reports on a commercial Ni- Mo/Al{sub 2}O{sub 3} hydroprocessing catalyst that was deactivated with from 1 to 10 wt% coke in operation either light catalytic cycle oil (LCCO) or coal residuum. Coke deposition occurred during the first 20 h. For LCCO, quantity and aromaticity of as measured by {sup 13}C MAS NMR dependent reactor temperature, increasing 1.5% carbon 40% aromatic (sp{sup 2} carbon) at 335{degrees}C 3.0% 70% 395{degrees}C. Rate constants for hydrogenation, hydrodesulfurization (HDS), hydrodenitrogenation (HDN) were approximately 10% lower coked LCCO 20% 395{degrees}C than coke-free catalyst. At higher levels, however (10.6 C residuum), about 75% hydrogenation HDS activity 95% HDN lost. From N{sub pore size distribution, thickness molded estimated be 0.3 0.5 nm 1.5 3.0 C, respectively.