Catalyst system for hydrotreating hydrocarbons

摘要

This invention provides a layered catalyst system for hydro-denitrification of hydrocarbons, such as vacuum gas oil, used for hydrocracking to produce various fuels. The layered catalyst system of this invention comprises a first layer of a nickel-molybdenum-phosphorus/alumina catalyst or a cobalt-molybdenum-phosphorus/alumina catalyst and a second layer catalyst comprising a nickel-tungsten/silica-alumina-zeolite or a nickel-molybdenum/silica-alumina-zeolite catalyst. The preferred aspects of the combination of the layered catalysts disclosed herein are: (a) the first layer alumina catalyst has a molybdenum content greater than about 14% by wt.; (b) the first layer alumina catalyst has a relatively large pore size, such as at least about 60 ANGSTROM ; and (c) the second layer catalyst contains at least about 2% of a zeolite component. The layered catalyst system of this invention and the attendant process produces improved denitrification of feedstocks, improved catalyst life and other advantages.