GB1378829A - Hydrocracking process for converting heavy hydrocarbons into low- sulphur gasoline - Google Patents

Abstract

1378829 Hydrocracking TEXACO DEVELOPMENT CORP 8 Dec 1972 [27 Dec 1971] 56856/72 Heading C5E A heavy hydrocarbon oil containing compounds of sulphur, of nitrogen and of metals is hydrocracked in two stages to produce a major proportion of gasoline and a minor proportion of heavy fuel oil, both of low sulphur content. In the first stage the catalyst comprises a metal of Group VI or of Group VIII or an oxide, sulphide or mixture thereof, supported on an amorphous inorganic oxide having pore openings of at least 20 Šngstrom. The product of this stage is fractionated to separate gas oil from a residual fraction, and the gas oil is hydrocracked in the second stage over a catalyst which comprises a metal of Group VI or of Group VIII or an oxide, sulphide or mixture thereof, supported on an inorganic oxide having pore openings in the range from 5 to 20 Angstroms to yield gasoline. As shown, heavy oil in line 1 is combined with hydrogen from line 4 and optionally also with recycled gas oil from line 3 and residual oil from line 2, and hydrocracked in zone 5. The product is separated at 7 into a gas fraction of which part is vented at 8 and part recompressed at 10 and recycled with make-up from 11, and a liquid fraction which is fractionated at 15. Dry gas and gasoline are taken off at 27 and 28, and residual fuel is taken off at 17, or part of it recycled by line 2. Gas oil is taken by line 18 to be mixed with hydrogen from line 19 and cracked in zone 20, but part of it may be recycled by line 3 to zone 5. The product from zone 20 is separated at 22 in the same way as that from zone 5 at 7, and the liquid phase is mixed with that from separator 7 for fractionation at 15. The temperature in the second cracking zone is limited to 700‹ to 780‹ F., but that in the first may rise higher, e.g. up to 850‹ F. The base of the catalyst in the first cracking zone may be alumina, silica-alumina, silica-zirconia, silica-titania or a mixture of these; that in the second may be chemically similar or may be a zeolitic molecular sieve cation-exchanged with H<SP>+</SP>, NH 4 <SP>+</SP>, Ca<SP>++</SP>, Mg<SP>++</SP>, Zn<SP>++</SP>, a rare earth metal ion or a mixture of these. The hydrogenating component of the first catalyst may be Co-Mo, CoO-MoO 3 , CoS-MoS 3 , Ni-Co-Mo, NiO-CoO-MoO 3 or NiS-CoS-MoS 3 ; of the second Ni-W, NiO-WO 3 , NiS-WS 3 , CoS-MoS 3 or NiSCoS-MoS 3 .