| 摘要 |
A metal- and/or sulfur contaminated charge stock containing residua is hydrotreated in a first reaction zone in the presence of a hydrotreating catalyst comprising a hydrogenating component selected from the Group VIB and Group VIII metals, preferably a combination of nickel and molybdenum, on a refractory support, preferably alumina or silica-alumina, to reduce the metal and/or sulfur content thereof, the demetalated and/or desulfurized residua is hydrocracked in a second reaction zone in the presence of a hydrocracking catalyst comprising a nickel and tungsten impregnated rare earth exchanged zeolite X in combination with a nickel and tungsten impregnated silica-alumina matrix to provide distillate of higher cetane index than that achieved with hydrotreatment alone, and the liquid effluent from said second reaction zone is thereafter passed to a third reaction zone containing a hydrotreating catalyst which is the same as, or is different from, the hydrotreating catalyst in the first reaction zone to effect further hydrotreatment.
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