Patent GB-1001449-A (GB)
Title: Hydrocarbon conversion process
IPC: C10G69/00
Filed: 1963-03-28
Abstract: <PICT:1001449/C4-C5/1> A crude hydrocarbon feed is substantially all converted t fuel values in a high liquid yield in a process comprising separating said crude feed into fractions including light gasoline, heavy gasoline, gas oil and residual fractions, converting at least a portion of said gas oil to gasoline in a hydrocracking zone, converting at least a portion of said gas oil to a gasoline in a first catalytic cracking zone, and converting at least a portion of said residual fractions to gasoline in a second catalytic cracking zone operating at a per pass conversion not exceeding 35%.  In a preferred embodiment, said light gasoline is recovered as a product, said heavy gasoline is converted in a catalytic reformer to gasoline of higher octane number, a light gas oil is converted to gasoline in a hydrocracking zone, a heavy gas oil is converted in a catalytic cracking zone to gasoline and cycle oil and a substantial portion of the residual fractions are converted in a second catalytic cracking zone operating at a per pass conversion not exceeding 35% to gasoline and cycle oil.  The second catalytic cracking zone operates at above 950 DEG F. and a space velocity of above 25/V./V./hr.  As shown in the Figure, in crude column 2, operating at up to 800 DEG  F., crude oil is stripped of a light gasoline fraction which is removed through line 3, a heavy gasoline fraction which is passed through line 4 to reformer 5, a light gas oil fraction which is passed through line 10 to hydrocracking zone 11 and a heavy gas oil fraction which is passed through line 12 to conventional cracking zone 13 or to hydrocracking zone 11.  A residue is passed through line 14 to deasphalting zone 15 and then to catalytic cracker 17 which is operated at low conversion, e.g. 30 to 35% at 1000 DEG  F. and 15 p.s.i.g. with a low-activity silica-alumina catalyst, which may be continuously discarded and replaced by catalyst from catalytic cracker 13.  In addition catalyst may be withdrawn and demetallized.  The catalyst is separated from the oil product in separator 21 and the oil is passed to distillation column 26 from which (a) a C3-C4 fraction is passed to alkylation zone 28, (b) a light gasoline fraction is withdrawn through line 29 and 30 as product, (c) a heavy gasoline fraction is passed through lines 35 and 4 to a catalytic reformer 5, (d) a light cycle oil is passed through line 40 to hydrocracker 11, and (e) a heavy cycle oil may be passed through lines 41 and 41A and then to catalytic cracker 13 via line 42 or to extraction zone 44 via line 43, from which zone is obtained (1) an aromatic extract fraction which is passed to hydrocracker 11 and (ii) a raffinate fraction which is passed to catalytic cracker 13.  In addition, the heavy cycle oil may be passed through lines 41 and 41B to hydrocracker 11. Reaction products from cracker 13 are separated in distillation column 58 into (a) a C3-C4 fraction which is passed through line 59 to alkylation zone 28, (b) a light cycle oil which is returned to hydrocracking zone 11, (c) a heavy gasoline fraction which passed through lines 65 and 4 to catalytic reformer 5.  Reaction products from hydrocracker 11 are separated in distillation column 75 into (a) an isobutane fraction which is passed to alkylation zone 28, (b) a light gasoline fraction recovered as product, (c) a heavy gasoline fraction which is passed through lines 82, 65 and 4 to reformer 5 and a 400 DEG F. + cycle oil which is recycled to either hydrocracker 11 or cracker 13, as desired.  A high-octance product alkylate is withdrawn from alkylation zone 28 through line 84, and a high-octane reformate is obtained from catalytic reformer 5 through line 85.  The catalytic cracking zones 13 and 17 operate under conventional cracking zone conditions, e.g. 850 DEG  to 1000 DEG  F. and 10 to 30 p.s.i.g., zone 13 may be either a moving bed or fluid type and zone 17 is preferably a transfer line catalytic cracker.  The supply feed to hydrocracking unit 11 may be denitrified before contacting in the hydro-cracking unit at 400 DEG  to 750 DEG  F. and at least 500 p.s.i.g. using as cracking component silica alumina, silica-magnesia, silica-alumina-zirconia, alumina-boria fluorided composites and acid treated clays.  The hydrogenating-dehydrogenating component is selected from Group VI, VII and VIII metals and oxides and sulphides thereof, alone or together with promoters or stabilizers, e.g. oxides or sulphides of molybdenum, tungsten vanadium chromium, iron nickel, cobalt and platinum.  Reforming zone 5 operates at 700 DEG  to 1000 DEG  F., an L.H.S.V. of 0. to 10.0, a hydrogen pressure of 100 to 1000 p.s.i.g. and the molar ratio of hydrogen to hydrocarbon charge being 1.0 to 20.0.  Suitable catalysts are selected from Group VI and VIII and include platinum or palladium metal, silica alumina, silica zirconia, alumina-boria and alumina-halogen-activated alumina. Alkylation zone 28 operates at 40 DEG  to 55 DEG  F. using H2SO4 and at 40 DEG  to 100 DEG  F. with HF as catalyst materials.  Definitions are provided for the following terms crude, light gasoline, heavy gasoline, gas oils, residual stocks and cycle oils and all boiling points refer to atmospheric pressure distillations.  Starting materials specified are Mid-Continent, Middle-East, Canadian, West Texas or East Texas crudes, and oils recovered from shale gibsonite and tar sands. The example given tabulates and compares the product materials from a conventional process and a process according to the present invention, the latter process providing increased yields of gasoline.