US2998380A - Catalytic cracking of reduced crudes - Google Patents

Description

Aug. 29, 1961 K. w. MCHENRY ET AL 2,998,380

CATALYTIC CRACKING 0F REDUCED CRUDES Filed Feb. 27, 1959 u U) e Q g LQ u. m. E y; a E E D QQ D Q 8@ Q m Q 0o Q lo go Q /ln O3 l() J r\ i F HOlVHVdEIS l Y f lf3 o3 Q W D vf l0 f N Hamam NBSOHGH a l rq/ T m S v f E "a n S g fd Haselnuss Q E ik, 5&1 Eg E Q: G ,g 5%@ g/ Q N b um KOH wf ab I Q p A "Vm aoLvNolLov/ua m 03 "3 g N n, ft

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n), gg Keith W McHenry Herman S. Seel/g HOLVNOILOVHj Harry M. Brennan Ra/p M. Gar/ Reduced Crude tamination levels do not become excessive.

CATALYTIC CRACKING F REDUCED CRUDES Keith W. McHenry, Park Forest, Ill., and Herman S.

Seelig, Valparaiso, and Harry M. Brennan and Ralph W. Carl, Hammond, Ind., assignors to Standard Oil Company, Chicago, Ill., a corporation of Indiana Filed Feb. 27, 1959, Ser. No. 796,034 16 Claims. (Cl. 208-72) This invention relates to a method of refining petroleum crude oil and, more particularly, to a refining process combination which includes ycatalytic crackin-g of metalcontaminant-containing reduced crudes and utilization of the increased hydrogen production associated with such catalytic cracking operation for the upgrading of other hydrocarbon streams.

In the refining of petroleum crude oils it is customary to fractionate the crude oil into at least a virgin naphtha fraction, a virgin gas oil fraction, and a heavy bottoms fraction which is also customarily referred to as reduced crude. To increase both the yield and quality of desired products from the refining operation, eg., high octane naphtha, high-purity light gas oils, and the like, the refining operation normally includes the catalytic reforming of at least the virgin naphtha fraction to produce a high-octane reformate and the catalytic cracking of at least the virgin gas oil fraction to produce additional naphtha and light gas oils. The reduced crude fraction also contains components which could advantageously be subjected to catalytic cracking, but unfortunately there are normally present in reduced crudes various metal contaminants, eg., copper, nickel, vanadium, iron, and the like, usually in the form of metal organics, which poison cracking catalysts, e.g., silica-alumina, natural clays, and the like. Metallic contamination of catalytic cracking catalyst manifests itself in the form of increased production of gases, primarily hydrogen, decreased production of catalytic naphtha, and increased deposition of carbonaceous deposits on the catalyst, all of which changes have heretofore made the refining operation economically unattractive.

Various solutions have been attempted to cope with the problem of metallic contamination of cracking catalyst. For example, reduced crudes have been subjected to a prior refining step, e.g., coking, which results in a demetallized gas oil. Attempts have also been made to treat the catalyst so as to remove or mask the e'ects of metal contaminants, e.g., by steaming the catalyst. Still another attempted alternative is the employment of a high rate of catalyst addition and discard so that con- All of such techniques, however, are costly and are reflected in higher product prices.

We have now discovered a refining process combination which converts the disadvantages of catalytic cracking of reduced crudes into an advantageous method of operation. In short, in the broadest embodiment of our invention, we employ in our processing scheme the step of catalytically cracking metal-contaminant-containing reduced crude, not only to produce catalytic naphtha and gas o-il, but also to produce a gaseous stream rich in hydrogen, ie., containing at least about 50 mol percent hydrogen; thereafter, the hydrogen is employed in a hydrogenation step to upgrade one or more hydrocarbon streams so that the economics of the overall operation are substantially improved, therebgy making catalytic cracking of reduced crude economically attractive.

More speciiicially, our method of refining a petroleum crude oil includes the steps of fractionating crude oil into at least a virgin naphtha fraction, a virgin gas oil fraction, and a bottoms fraction containing metal contam- 2,998,386 Patented Aug. 29, '1961 inants; subjecting the bottoms fraction to hydrocarbon cracking conditions in the presence of a hydrocarbon cracking catalyst whereby at least a portion of the bottoms fraction is converted to a hydrogen-rich gaseous stream, a cracked naphtha stream, a cracked `gas oil stream, and carbonaceous and metal-'contaminant deposits on the catalyst; and contacting at least a por-tion of hydrocarbons derived from the crude oil under hydrogenation conditions with the hydrogen-rich Ygaseous stream so as to improve the quality thereof. The portion of hydrocarbons which is hydrogenated may comprise all or part of the cracked gas oil stream, the virgin gas oil fraction, mixtures of the two, or any of the available hydrocarbon streams which would benefit from hydrogenation. EFor example, the hydrogen-rich dry gas stream from reduced crude cracking may be used to hydrogenate the virgin gas oil and/or the cracked gas oil from the reduced crude cracker so as to remove sulfur and nitrogen and saturate refractory aromatics. The resulting hydrogenated gas oil may then be fractionated to produce high quality distillate fuels, eg., heater oils, furnace oils, jet fuels, and the like. Alternatively, the hydrogenated gas oil, which is substantially free of metals, may be used as charge stock to a second catalytic cracking unit without any risk of catalyst contamination.

In a more specific embodiment of the present invention, used catalysts from the second catalytic cracking unit, to which only clean gas oils are charged, may be subsequently employed as a source of catalyst for the reduced crude catalytic cracking unit. Since the reduce-d crude cracker is normally operated at relatively low severity, used catalyst from the clean gas oil cracker is highly satisfactory for such purpose. In this embodiment, used catalyst from the clean gas oil catalytic cracking unit may be intermittently or continuously transferred to the reduced catalytic cracking unit. In the case of catalytic cracking units employing iiuidized cracking catalyst, the transfer of catalyst may advantageously, but not necessarily, be carried out continuously, e.g., at the same rate as catalyst is lost via the stack of the reduced crude cracking unit.

In another embodiment of the present invention the virgin naphtha which is fractionated from crude oil may be catalytically reformed, alone or in admixture with other naphtha streams, eig., catalytic naphtha from the catalytic cracking units, so as to produce a high octane liquid reformate product and a hydrogen-rich gaseous stream, part of which is recycled to the reforming operation. All or part of the balance of the hydrogen-rich gaseous stream may be combined with the hydrogen-rich gaseous stream from the reduced dcrude catalytic cracking unit and employed in the gas oil hydrogenation step.

The present invention and advantages associated therewith will be more clearly understood from the following detailed description, which should be read in conjunction 4with the accompanying figure,l which forms a part of this specification. The figure shows in schematic detail one specific embodiment of the present invention wherein both a reduced crude catalytic cracking unit and a separate gas oil catalytic cracking unit are employed, with transfer of catalyst from the gas` oil unit to the reduced crude unit.

Referring to the figure, a petroleum crude oil from source 10 passes via line 11 to primary fractionator 12, wherein a Agaseous stream is separated and removed via line 12a, a virgin naphtha stream via line 13, a virgin (based on reduced crude), or more, of metal contaminants, e.g., organic compounds of nickel and/or vanadium, which contaminants quickly poison cracking catalysts and which have heretofore rendered catalytic crack-- ing of reduced crudes economically unattractive. Rather than attempt to remove the metals by subjecting the reduced crude, for example, to a coking operation, the reduced crude in accordance with the present invention is charged directly to catalytic cracking. Accordingly, in the figure the reduced crude from line 15 is mixed in line 16 with regenerated catalyst from regenerator 17 and line 18 (and used, but metal-contaminant-free, catalyst from line 60, hereinafter discussed) and passes to catalytic cracking reactor 19, wherein it is subjected to cracking conditions in the presence of a fluidized cracking catalyst, i.e., a cracking catalyst having a particle size principally in the 20-80 micron range. The cracking catalyst may be any of `a number of catalysts now available, e.g., acid-leached bentonite clay, manufactured silica-alumina, manufactured silica magnesia, and the like. The catalyst, which becomes fouled with metal contaminants and carbonaceous deposits in reactor 19, is removed via line 20 (after steam stripping) and is passed via line 21 to regenerator 17 along with an oxygen-containing stream, e.g., air, introduced via line 22.

Cracking conditions are well known in the art and normally include a temperature in the range of about 850 to 950 F., a pressure in the range of about 2 to 20 pounds per square inch gauge, a weight-hourly space velocity (weight of oil per hour divided by weight of catalyst in the reactor) in the range of about 0.5 to 5.0, and a catalyst to oil weight ratio in the range of about 1.5 to 15. For reduced crude cracking, operating conditions `are usually selected so as to obtain a relatively low conversion of about 20 to 40 volume percent (100 minus volume percent of cycle oil, based on reduced crude charge). Normally recycling of cracked gas oil is not employed in the reduced crude catalytic cracking unit, and catalyst is discarded by means of normal regenerator stack losses, i.e., via line 23. Carbonaceous deposits are removed in regenerator 17 by combustion in the air introduced via line 22, any excess heat resulting from such combustion usually being removed by heat exchange, e.g., by means of a stream generator. Little if any of the metallic contaminants on the catalyst are removed in regenerator 17 so that the substantially carbon-free catalyst leaving via line 18 may typically contain up to about 10,000 parts per million (based on catalyst) of metallic contaminants, e.g., 2,000 to 8,000 parts per million.

Cracked product passes from reactor 19 via line 24 to fractionator 25 wherein a hydrogen-rich dry gas is separated yand removed via line 26, `light ends, e.g., predominantly C1-C4 hydrocarbons via line 27, catalytic naphtha via line 28, cracked gas oil via line 29, and decanted oil via line 30. Because of metallic contaminants on the catalytic cracking catalyst, which are believed to act as dehydrogenation catalysts, the dry gas leaving fractionator 25 via line 26 normally contains at least about 50 mol percent hydrogen. For example, when cracking a West Texas reduced crude over a catalyst contaminated with only about 200 parts per million of V205 `and NiO, hydrogen production is about 65 standard cubic feet per barrel of charge, resulting in a hydrogen concentration in the dry gas of only 25 mol percent. As soon as catalyst contamination reaches the level of about 6,000 parts per million, however, hydrogen production increases to over 400 standard cubic feet per barrel, resulting in a hydrogen concentration in dry gas of about 70 mol percent or more. The present invention takes advantage of this increased hydrogen production so as to make reduced crude catalytic cracking economically feasible.

In the present embodiment the hydrogen-rich gas in line 26 is combined with hydrogen-rich gas from line 31 and recycled hydrogen from line 32 land charged via line 33 to scrubber 34, wherein a suitable scrubbing medium, e.g., caustic, water, and the like, is employed to scrub out undesired contaminants, e.g., hydrogen sulfide, ammonia, and the like. Hydrogen-rich gas from line 31 is produced by the catalytic reforming of virgin naphtha which passes from primary fractionator 12 via line 13 to reforming zone 35. Reforming zone 35 is typically a multi-reactor, fixed-bed catalytic reforming process such as Ultraforming (Petroleum Engineer, vol. XXVI, No. 4, April 1954, at page C-35). The catalyst may comprise platinum and alumina and is typically a halide-containing platinum-alumina catalyst having about 0.1 to 1.0 percent by weight of platinum and about 0.1 to 3.0 percent by weight of halogen, usually fluorine or chlorine. Various methods are taught in the art for the preparation of such reforming catalysts (see, for example, Heard et al., U.S.P. 2,659,701 and Hunter et al., U.S.P. 2,746,937). Reforming conditions in zone 35 may include a temperature in the range of about 850 to l050 F., a pressure in the range of about to 1,000 pounds per square inch gauge, a weight-hourly space velocity of about 0.5 to 5.0, and a hydrogen recycle rate of about 1,000 to 10,000 standard cubic feet per barrel of naphtha feed.

Hydrogen-rich gas leaves reforming zone 35 via line 36, and a portion of the gas is recycled via line 37. Light ends, e.g., (l-C4 hydrocarbons, are removed via line 38 and stabilized reformate is removed via line 39. As previously mentioned, a portion of the hydrogen-rich gas from reforming zone 35 may be employed in the hydrogenation step (to be described hereinafter) and, for such purpose, passes via lines 31 and 33 to scrubber 34. Any excess hydrogen gas produced in reforming zone 35 may be discarded to fuel or other processing via line 40.

Purified hydrogen-rich gas from scrubber 34 passes via line 41 to line 42, where it is admixed with virgin gas oil and cracked gas oil from line 43, the virgin gas oil from primary fractionator 12 reaching line 43 via line 14, and the cracked gas oil reaching line 43 via line 29. The mixture of virgin gas oil, cracked gas oil, and hydrogen-rich gas is contacted with a hydrogenation catalyst in hydrogen treater 44, said hydrogenation catalyst typically being a cobalt-molybdenum-type hydrogenation catalyst, commercially available from at least several wellknown catalyst manufacturers. Hydrogenation conditions include `a temperature in the range of about 650 to 900 F., e.g., 700 to 750 F., a pressure in the range of about 300 to 2,000 pounds per square inch gauge, e.g., about 650 to 750 pounds per square inch gauge, a volumetric space velocity (volume of gas oil per hour per volume of catalyst) of about 1.0 to 6.0, c g., yabout 2.0 to 3.0, and a hydrogen `addition rate of about 500 to 10,000 standard cubic feet per barrel of gas oil feed, eg., about 1,000 to 4,000 standard cubic feet per barrel. Hydrogen consumption in hydrogen treater 44 is typically in the range of about 100 to 1,000 standard cubic feet er barrel of gas oil feed.

Hydrogenated gas oil product from hydrogen treater 44 passes via line 45 to separator 46, wherein hydrogenrich gas is separated and recycled via lines 47, 32, and 33, scrubber 34, and lines 41 and 42, or, alternatively, via lines 47, 48, and 42, thereby bypassing scrubber 34. Hydrogenated gas oil leaves separator 46 via line 49 and is combined with recycled cracked gas oil from line 50 in line 51 `and passed, along with regenerated catalyst from regenerator 52 and line 53, via line 54 to catalytic cracking reactor 55.

Catalytic cracking conditions in reactor 55 are adjusted so as to obtain a substantially higher conversion, i.e., above about 40 volume percent, than employed in reduced crude catalytic cracking reactor 19. Because the `gas oil charge has been upgraded by hydrogenation, catalytic naphtha yields from reactor 55 are increased as much as about 4 volume percent and octane number by as much as about 3 research octane units, and coke deposits on catalyst are substantially reduced. Because the hydrogenated gas oil feed is substantially metal-free, the catalyst leaving reactor 55 via line 56 contains substantially no metal poisons, and when sent to regenerator 52 via line 57 along with air from line 58, the resulting combustion of carbonaceous deposits provides a substantially contaminant-free catalyst for recirculation via line 53. In addition to normal stack losses via line 59, a portion of the regenerated cracking catalyst is continuously or intermittently transferred from line 53 via line 60 to line 18, where it is combined with regenerated catalyst from regenerator 17. As a result of this deliberate discard of catalyst from the gas oil catalytic cracking unit to the reduced crude catalytic cracking unit, and the replacement of such lost and discarded catalyst with fresh catalyst, a very high Vactivity level is maintained in the gas oil catalytic cracking unit, while at the `same time there is no loss of cracking catalyst in the overall system other than unavoidable stack losses.

Cracked products from reactor 55 pass via line 61 to fractionator 62, wherein they are separated into a dry gas stream which leaves via line 63, a light ends stream via line 64, a catalytic naphtha stream via line 65, a cracked gas oil stream via line 66 and a decanted gas oil stream via line 67. Because of the metal-contaminantfree condition of the cracking catalyst in reactor 55, the dry gas leaving via line 63 has a relatively low hydrogen content. A portion of the cracked gas oil stream in line 66 is normally recycled via lines 50, 51, and S4.

As a result of the above combination, it is apparent that reduced crude can now be catalytically cracked without prior purification and/or demetallization. The upgrading of cracked gas oil and/ or virgin gas oil by hydrogenation is carried out entirely with internally-produced hydrogen. The overall gasoline yields, particularly yields of catalytically cracked naphtha, are enhanced and the quality of the gasoline, i.e., octane number, is substantially increased. Furthermore, because gas oils charged t0 the gas oil catalytic cracking unit have been hydrogenated, and thus desulfurized, the lead response ofthe gasoline is substantially improved. As a result of these improvements, catalytic cracking of reduced crude is now economically feasible whereas heretofore such processing could not be justified on a commercial scale.

While the present invention has been described with reference to certain specific embodiments thereof, it is to be understood that such embodiments are illustrative only, and not by Way of limitation. Numerous additional and/ or alternative manipulative steps, including other catalytic cracking, hydrogenation and reforming operating conditions and equipment and other processing steps, e.g., hydrogen treating of virgin naphtha, processing of light hydrocarbons by `alkylation, polymerization, isomerization and/or Ithe like, will be apparent from the above detailed description to those skilled in the art, and these are included within the spi-rit of the present invention.

Having thus described the prent invention, what is claimed is:

l. A method of refining a petroleum crude oil containing metal contaminants comprising compounds of nickel and vanadium which method comprises in combination the steps of fractionating said crude oil into at least Ia virgin naphtha fraction, a virgin gas oil fraction, Iand a residual bottoms fraction containing metal contaminants; subjecting said bottoms fraction to hydrocarbon catalytic cracking conditions in a `first cracking zone in the presence of a hydrocarbon cracking catalyst whereby at least a portion of said bottoms fraction is converted to at least a first hydrogen-rich gaseous stream, a cracked naphtha stream, a cracked gas oil stream, and carbonaceous and metal containing deposits on catalyst said metal containing deposits comprising compounds of nickel and vanadium and being present in amounts eiective to increase the amount of hydrogen in said rst gaseous stream whereby said rst gaseous stream is made hydrogen-rich; contacting at least a portion of hydrocarbons derived from said crude oil under hydrogenation conditions with said irst hydrogen-rich gaseous stream in the presence of a hydrogenation catalyst.

2. The method of claim 1 wherein said portion of hydro'- carbons comprises at least a portion of said cracked gas oil stream.

3. The method of claim l wherein said portion of hydrocarbons comprises at least a portion of said virgin gas oil fraction.

4. The method of claim l wherein said portion of hydrocarbons comprises a blend of said cracked gas oil stream and said virgin gas oil fraction.

5. The method of claim l wherein the hydro genated portion of hydrocarbons is thereafter subjected to hydrocarbon cracking conditions in a second cracking zone in the presence of a hydrocarbon cracking catalyst.

6. The method of claim 5 wherein the hydrocarbon cracking catalyst employed in said first cracking zone comprises Iat least a portion of hydrocarbon cracking catalyst previously employed in said second cracking zone.

7. The method of claim 1 including the steps of contacting said virgin naphtha fraction under reforming conditions with a catalyst comprising platinum and alumina so as to produce at least a liquid reformate product of substantially higher octane number and a second hydrogen-rich gaseous stream, `and employing at least a portion of said second hydrogen-rich gaseous stream along with said iirst hydrogen-rich gaseous stream in the hydrogenation step.

8. The method of refining a petroleum crude oil containing rnetal contaminants comprising compounds of nickel and vanadium which method comprises in combination the steps of fractionating said crude oil into at least a virgin naphtha fraction, -a virgin gas oil fraction, and a residual metal-contaminant-containing bottoms fraction; subjecting said bottoms fraction to hydrocarbon catalytic cracking conditions in a tirst cracking zone in the presence of a hydrocarbon cracking catalyst whereby at least a portion of said bottoms fraction is converted to at least a irst hydrogen-rich gaseous stream, Ia cracked naphtha stream, a cracked gas oil stream, and carbonaceous and metal containing deposits on said catalyst said metal containing deposits comprising compounds of nickel and vanadium and being present in amounts elfective to increase the amount of hydrogen in said rst gaseous stream whereby said rst gaseous stream is m-ade hydrogenrich; contacting at least a portion of said virgin gas oil traction and said cracked gas oil stream under hydrogenation conditions with said irst hydrogen-rich gaseous stream in the presence of a hydrogenation catalyst; and subjecting the resulting hydrogenated gas oil to hydrocarbon cracking conditions in a second cracking zone in the presence of a hydrocarbon cracking catalyst.

9. The method of claim 8 wherein the hydrocarbon cracking catalyst employed in said rst cracking zone comprises at least a portion of hydrocarbon cracking catalyst previously employed in said second cracking zone.

10. The method of claim 8 including the steps of contacting said virgin naphtha fraction under reforming conditions with a catalyst comprising platinum and alumina so as to produce at least a liquid reformate of substantially higher octane number and a second hydrogen-rich gaseous stream; land employing at least a portion of said second hydrogen-rich gaseous stream along with said tirs-t hydrogen-rich gaseous stream in the hydrogenation step.

11. A method of refining a petroleum crude oil containing metal contaminants comprising compounds of nickel `and vanadium which method comprises the steps of fraction-ating said crude oil into at least a virgin light oil fraction and a bottoms fraction containing metal contaminants from said crude oil; subjecting said bottoms fraction containing metal contaminants to hydrocarbon cracking conditions in a first cracking zone in the presence of a cracking catalyst whereby at least a portion of said bottoms fraction is converted to at least a hydrogen rich gaseous stream, a cracked light oil stream and a carbonaceous metal containing deposit on said cracking catalyst said metal containing deposit comprising mpounds of nickel and vanadium and being present in amounts effective to increase the amount of hydrogen in said gaseous stream whereby said gaseous stream is made hydrogen-rich; contacting at least a portion of said cracked light oil stream with said hydrogen rich gaseous stream in the presence of a hydrogenation catalyst under hydrogenation conditions; and recovering a hydrogenated light oil from said hydrogenation zone.

12. A method of refining a petroleum crude oil containing metal contaminants comprising compounds of nickel and Vanadium which method comprises the steps of fnactionating said crude oil into at least a virgin light oil fraction and a bottoms fraction containing metal contaminants from said crude oil; subjecting said bottoms fraction containing metal contaminants to hydrocarbon cracking conditions in a rst cracking zoneV in the presence of a cracking catalyst whereby at least a portion of said bottoms fraction is converted to at least a hydrogenrich gaseous stream, a cracked light oil stream and a carbonaceous metal containing deposit on said cracking catalyst, said metal containing deposit comprising corripounds of nickel and vanadium and being present in amounts effective to increase the amount of hydrogen in said gaseous stream whereby said gaseous stream is made hydrogen-rich; contacting at least a portion of said cracked light oil stream with said hydrogen 'rich gaseous stream in a hydrogenation zone in the presence of a hydrogenation catalyst under hydrogenation conditions; and subjecting at least a portion of a hydrogenated light oil recovered from Vsaid hydrogenation zone concurrently with at least a portion of said virgin light oil to Yhydrocarbon cracking conditions in a second cracking zone in the presence of a hydrocarbon cracking catalyst.

13. The method of claim 1 wherein said deposits contain up to about 10,000 ppm., based on catalyst, of metallic compounds.

14. The method of claim 8 wherein said deposits contain up to about 10,000 ppm., based on catalyst, of metallic compounds.

15. The method of claim 11 wherein said deposits contain up to Vabout 10,000 ppm., based on catalyst, of metallic compounds.

16. The method of claim 12 wherein said deposits contain up to about 10,000 ppm., based on catalyst, of metallic compounds.

References Cited in the le of this patent UNITED STATES PATENTS 2,309,137 Peterkin J an. 26, 1943 2,352,052 Seguy .Tune 20, 1944 2,360,622 Roetheli Oct. 19, 1944 2,371,355 Ross et al. Mar. 13, 1945 2,644,785 Harding et al. July 7, 1953 2,730,557 MaX et `al. Jan. 10, 1956 2,792,336 Kubicek etal. May 14, 1957 y UNITEDSTATES PATENT @FFME CERTIFICATE 0F CRRECTION Patent N0. 2,998,380 Y August 29? 1961 KeithkW. MoHenry et al..

It is hereby certified that error appears in ,the above numbered patentrequiring correction and that the said Lettere Patent should read 'as "corrected below.

v Column 3, lin-e 43 for' "stream" read steam Signed and sealed this 16th day of January 1962.

SEA L) Attest:

ERNEST W. SWIDERA DAVID L. LADD Attesting Officer Commissioner of Patents

Claims (1)

1. A METHOD OF REFINING A PETROLEUM CRUDE OIL CONTAINING METAL CONTAMINANTS COMPRISING COMPOUNDS OF NICKEL AND VANADIUM WHICH METHOD COMPRISES IN COMBINATION THE STEPS OF FRACTIONATING SAID CRUDE OIL INTO AT LEAST A VIRGIN NAPHTHA FRACTION, A VIRGIN GAS OIL FRACTION, AND A RESIDUAL BOTTOMS FRACTION CONTAINING METAL CONTAMINANTS, SUBJECTING SAID BOTTOMS FRACTION TO HYDROCARBON CATALYTIC CRACKING CONDITIONS IN A FIRST CRACKING ZONE IN THE PRESENCE OF A HYDROCARBON CRACKING CATALYST WHEREBY AT LEAST A PORTION OF SAID BOTTOMS FRACTION IS CONVERTED TO AT LEAST A FIRST HYDROGEN-RICH GASEOUS STREAM, A CRACKED NAPHTHA STREAM, A CRACKED GAS OIL STREAM, AND CARBONACEOUS AND METAL CONTAINING DEPOSITS ON CATALYST SAID METAL CONTAINING DEPOSITS COMPRISING COMPOUNDS OF NICKEL AND VANADIUM AND BEING PRESENT IN AMOUNTS EFFECTIVE TO INCREASE THE AMOUNT OF HYDROGEN IN SAID FIRST GASEOUS STREAM WHEREBY SAID FIRST GASEOUS STREAM IS MADE HYDROGEN-RICH, CONTACTING AT LEAST A PORTION OF HYDROCARBONS DERIVED FROM SAID CRUDE OIL UNDER HYDROGENATION CONDITIONS WITH SAID FIRST HYDROGEN-RICH GASEOUS STREAM IN THE PRESENCE OF A HYDROGENATION CATALYST.

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