| 摘要 |
1,161,725. Hydrocracking. MOBIL OIL CORP. 17 Oct., 1967 [17 Oct., 1966], No. 47248/67. Heading CSE. A process for selectively producing gasoline boiling range hydrocarbons by hydrocracking comprises contacting under hydrocracking conditions a heavy petroleum hydrocarbon feed containing less than 500 p.p.m. organic nitrogen with an amorphous base hydrocracking catalyst and a zeolite base hydrocracking catalyst, said contact being carried out in a series of catalyst beds wherein said amorphous base catalyst is separated from said zeolite base catalyst, said amorphous base catalyst containing a hydrogenation component and having a Cat A activity index above 20, said zeolite base catalyst having pore size openings between 6 Angstroms and 15 Angstroms and containing a hydrogenation component and less than 5 weight per cent sodium oxide, recovering a normally liquid effluent from the last catalyst bed, separating a gasoline boiling range fraction from said liquid effluent, and recycling at least a portion of the liquid effluent boiling above the gasoline range to contact the amorphous base hydrocracking catalyst bed. It is possible to use the amorphous base catalyst first, but it is preferred to use the zeolite base catalyst first and the amorphous base catalyst second. The amorphous base catalyst may comprise silicaalumina, silica-zirconia, silica-magnesia, silica, or alumina containing a hydrogenation component such as iron, nickel, cobalt, the platinum group metals, or the palladium group metals; preferred examples being nickel-tungsten sulphide, nickel sulphide, cobalt-molybdenum sulphide, platinum and palladium. The zeolite catalyst comprises a natural or synthetic zeolite carrier which may be base-exchanged with a hydrogen-containing cation or a metallic cation such as nickel or a rare earth metal, plus a hydrogenation component which may be chromium, molybdenum, tungsten, iron, nickel, cobalt, a platinum group metal or a palladium group metal; preferred components being nickel-tungsten, cobalt-molybdenum, platinum and palladium. There may be a preliminary hydrofining stage to reduce the amount of sulphur and nitrogen in the feed. |
