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Publication numberUS3267021 A
Publication typeGrant
Publication dateAug 16, 1966
Filing dateMar 30, 1964
Priority dateMar 30, 1964
Publication numberUS 3267021 A, US 3267021A, US-A-3267021, US3267021 A, US3267021A
InventorsGould George D
Original AssigneeChevron Res
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Multi-stage hydrocracking process
US 3267021 A
Abstract  available in
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Claims  available in
Description  (OCR text may contain errors)

Aug. 16, 1966 G. D. GOULD MULTI-STAGE HYDROCRACKING PROCESS Filed March 30, 1964 GEORGE D. GOULD BY A ,l I

ATTORNEYS United States Patent Office Patented August 16, 1956 3,267,021 MULTI-STAGE HYDROCRACKING PROCESS George D. Gould, Orinda, Calif., assigner to Chevron Research Company, a corporation of Delaware Filed Mar. 30, 1964, Ser. No. 355,653 2 Claims. (Cl. 208-78) This invention relates to a hydrocarbon conversion process, more particularly to a hydrocarbon conversion process for converting hydrocarbon feeds, including petroleum distillate and residuum feeds, into various valuable products, and still more particularly to a catalytic conversion process capable of producing middle distillates and gasoline from said feeds.

It yis well known that nitrogen in a hydrocarbon feed is deleterious to certain hydrocracking catalysts, particularly highly acidic hydrocracking catalysts, and that in order to provide a practical process for producing gasoline over a highly acidic hydrocracking catalyst from a feed containing substantial amounts of nitrogen, it Iis generally necessary to first hydrofne the feed to remove substantially all of the nitrogen. It is also well known that such highly acidic catalysts do not result in the production of substantial quantities of middle distillates and that where gasoline production and also substantial middle distillate production is desired a catalyst having no more than weak acidity is desirable. While it is possible to meet the aforesaid problems by operating a two-stage process wherein the hydrofining-hydrocracking catalyst having no more than weak acidity is used in the first stage and an acidic hydrocracking catalyst is used in the second stage, such a process still has undesirable aspects. Operation of the first stage at hydrolining conditions severe enough to reduce the nitrogen content of the feed to an acceptably low level, particularly where maximum middle distillate production is desired, frequently results in a greater amount of hydrocracking, gasoline and light gas production and catalyst fouling in the first stage than is desired. On the other hand, operation of the first stage at less severe conditions which do not result in an excessive amount of hydrocracking frequently leaves a greater concentration of nitrogen in the eiiiuent from the first stage than can be tolerated for sustained periods by the acidic catalysts in the second stage.

In View of the foregoing, it is an object of the present invention to provide a multi-stage process for converting raw feeds, including nitrogen-containing feeds, to gasoline and middle distillates wherein selected portions of said feeds are hydrocracked and partially hydrofined in each stage with catalysts having no more than weak acidity t produce middle distillate products and higher boiling materials and wherein selected portions of said higher boiling materials are hydrocracked in the same catalyst system in a manner which results in a maximum over-al1 production of middle distillates, at minimum cost, without excessive catalyst fouling in any stage.

The invention will best be understood, and further objects and advantages thereof will be apparent, from the following description when read in conjunction with the accompanying drawing which is a diagrammatic illustration of process units and flow paths suitable for carrying out the process of the present invention.

In accordance with one embodiment of the present invention there is provided a process for producing gasoline and middle distillates from a hydrocarbon feed selected from the group consisting of petroleum distillates and petroleum residua boiling `above 500 F., which comprises selecting at least two feed fractions boiling above 500 F. and having different boiling ranges, hydrocracking the lighter of said fractions in the presence of from 1,000 to 10,000 s.c.f. of hydrogen per -barrel thereof in a first conversion zone at a temperature from 500 to 950 F., a pressure above 500 p.s.i.g. and an LHSV of 0.1 to 4.0 with a catalyst having no more than weak acidity comprising at least one hydrogenating component selected from the Group VI metals and compounds of Group VI metals and at least one hydrogenating component selected from the Group VIII metals land compounds of Group VIII metals in intimate association 'with a silica-containing support, hydrocracking the heavier of said fractions in a second conversion zone under conditions within the aforesaid ranges with a catalyst having the aforesaid description, .recovering from each of said zones lat least one prodtuct boiling below the initial lboiling point of the feed to said zone, and passing heavier materials from each zone to said second zone only.

In accordance with a more specific embodiment of the present invention, there is provided a process for producing gasoline and middle distillates from a hydrocarbon feed selected from the group consisting of petroleum distillates and petroleum residua boiling above 650 F. which comprises separating said feed into a first fraction and a second fraction of different boiling range, hydrocracking said first fraction in the presence of from 1000 to 10,000 s.c.f. of hydrogen per 4barrel thereof in a first conversion zone at a temperature of from 500 to 950 F., ya pressure above 500 p.s.i.g., and an LHSV of from 0.1 t0 4.0 with a catalyst having no more than weak acidity comprising at least one hydrogenating -component selected from the Group VI metals and compounds of Group VI metals and at least one hydrogenating component selected from the Group VIII metals and compounds of Group VIII metals in intimate lassociation with a silica-containing support, recovering at least one product boiling Ibelow 550 F. from said first conversion zone, hydrocracking said second fraction in the presence of from 1000 to 10,- 000 s.c.f. of hydrogen per barrel thereof in a second conversion zone at a temperature of from 500 to 950 F., a pressure. above 500 p.'s.i.g., and an LHSV of from 0.1 to 4.0 with a catalyst having no more than weak acidity comprising at least one hydrogenating component selected from hte Group VI metals and compounds of Group VI metals and at least one hydrogenating component selected from the Group VIII metals and compounds of Group VIII metals in intimate association with a silicacontaining support, recovering at least one product boiling below 550 F. from said second conversion zone, 'and passing to said second conversion zone from each of said first and second conversion zones a fraction boiling above 550 F.

Suitable feeds for use in the process of the present invention are petroleum distillates, including nitrogencontaining petroleum distillates, and petroleum residua, including nitrogen-containing petroleum residua, from which fractions can be selected boiling above 500 F., preferably fractions boiling between 500,a F. and 1200 F., and mixtures of the foregoing. Heavy gas oils and catalytic cycle oils are excellent feeds to the process, as well as conventional FCC feeds and portions thereof. Residual feeds may include Minas and other parainictype residua as well as solvent decarbonized oils from a wide range of residua. Other suitable4 feeds include tar sand oils, shale oils and coal tar distillates.

The aforesaid catalysts having-no more than Weak acidity comprise at least one hydrogenating component selected from the Group VI metals and compounds of the Group VI metals and at least one hydrogenating component selected from the Group VIII metals and com* pounds of Group VIII metals. Preferred combinations of hydrogenating components include nickel sulfide and tungsten sulfide, nickel sulfide and molybdenum sulfide, and palladium sulfide and molybdenum sulfide.

The aforesaid catalysts having no more than weak acidity comprise a support, preferably one that is moderately acidic, but not more than moderately acidic, as compared with highly acidic supports such as silicaalumina. Said support preferably is selected from the group consisting of silica-magnesia supports, silicaalumina supports containing less than 70 weight percent of silica, and silica-alumina-magnesia supports having a silica content less than 80 weight percent.

The aforesaid catalysts having no more than weak acidity are relatively nitrogen-insensitive compared with conventional acidic hydrocracking catalysts such as nickel sulfide on silica-alumina. Accordingly, the nitrogen content of the feed used in the process of the present invention may be relatively high and excellent hydrocracking results still may be obtained in the conversion zones containing said catalysts at reasonable temperatures without the necesssity for rapidly raising the temperature to maintain conversion as is necessary when hydrocracking a high nitrogen content feed of a conventional acidic hydrocracking catalyst, such as nickel sulfide on silicaalumina. The nitrogen content of the feed in the present process may range from less than parts per million to 30,000 parts per million. The process is especially attractive for processing heavy feed containing at least 500 parts per million nitrogen.

Although high nitrogen content feeds can be tolerated by said catalysts having no more than weak acidity, it will be noted that said catalysts also are excellent hydrodenitrification catalysts and are efficient in concurrently hydrofining as well as in hydrocracking the feed. Nevertheless, the process of the present invention may be rendered even more efficient if very high nitrogen content feeds are rst hydrofined by conventional methods to at least somewhat reduce their nitrogen content before hydrocracking them in the presence of said catalysts having no more than weak acidity in accordance with the present invention.

Conversion zones in the process of the present invention containing said catalysts having no more than weak acidity are operated at combinations of conditions selected from within the following ranges that will produce the desired degree of hydrocracking: a temperature of about 500 to 950 F., preferably 650 to 850 F.; a hydrogen partial pressure of 500 to 3500 p.s.i.g., preferably 1000 to 2500 p.s.i.g.; and an LHSV of from about 0.1 to 4.0, preferably 0.4 to 2.0. The hydrogen flow to said conversion zones may be from 1000 to 12,000 s.c.f. per barrel of feed, and preferably 2500 to 8000 s.c.f. per barrel of feed. The higher hydrogen partial pressures, particularly with unrened feeds, give lower catalyst fouling rates, and therefore, for longer catalyst lives, it is preferable to operate above 2000 p.s.i.g. total pressure and above 1000 p.s.i.g. hydrogen partial pressure.

Referring now to the drawing, there shown is an exemplary diagrammatic illustration of an embodiment of process units and flow paths suitable for carrying out the process of the present invention.

A hydrocarbon feed which may be, and in this example is, a petroleum distillate feed containing materials boiling about 650 F., is passed through line 1 to distillation column 2, where it is separated into various fractions as shown. A gaseous fraction is removed from column 2 through line 3, a C5-650 IF. fraction is removed through line 4, and, if desired, a residuum fraction boiling above 110 F. is removed through line 5. A 650 to 900 F. fraction is passed from separation zone 2 through line 6 into contact in hydrocracking zone 7 with the aforesaid hydrocracking catalyst having no more than weak acidity and with hydrogen entering zone 7 through line 8 under the hydrocracking conditions previously discussed, at a per-pass conversion preferably above about 40%. From zone 7, an efuent is passed through line 9 to separation zone 10, from which hydrogen is recycled through line 15, ammonia is Withdrawn through line 16, and remaining materials are passed through line 17 to separation zone 18. From separation zone 18 product streams boiling below about 400 F., and from about 400 to 650 F., respectively, are withdrawn through lines 19 and 25, respectively. From separation zone 1S, materials boiling above about 650 F. are passed to hydrocracking zone 31, discussed below. If desired a portion of the materials in line 20 may be withdrawn through line 26 and passed to a catalytic cracking zone, or withdrawn completely from the system, or used for any other desired purpose, for example as a lube oil stock.

A 900 to 1l00 F. fraction, together with materials in line 20, is passed .from separation zone 2 through line 30 into |contact in hydrocrackinig zone 31 with the aforesaid hydrocrackinig catalyst having no more than weak acidity and with hydrogen entering zone 31 through line 32 under the hydrocracking conditions previously discussed, at a per-pass conversion preferably above about 40%. From zone 31 an efuent is passed through line .33 to separation zone 34 from which hydrogen is recycled through line 35 to zone 31, ammonia is Withdrawn through line 36, `and remaining materials are passed through line 37 to separation zone 38. From separation zone 38, products boiling below about 400 F., and from 400 to 650 F., respectively, are recovered through lines 39 and 46, respectively, and materials boiling above about 650 F. are returned to zone 31 through lline 40. A portion of the materials in line 40 may be passed through line 45 to a catalytic cracking zone, or removed completely from the system, or used for any other desired purpose, for example as a lube stock.

From the foregoing, it wifll be seen that the process of the present invention, wherein the first lhydrocracking zone is operated on a once-through basis and the second hydrocracking zone is operated on a recycle basis, is effective in producing middle distillates in good yields.

Although only specific embodiments of the present invention have been described, numerous variations can be made yof those embodiments without departing from the spirit of the invention, and all such variations that fall within the scope of the appended claims yare intended to be embraced thereby.

I claim:

1. A process for producing gasoline and middle distillates from a hydrocarbon feed boiling above 500 F. which comprises selecting at least two feed fractions boiling above 500 F. and having different boiling ranges catalyti-callly hydrocracking the lighter of said fractions in the presence of from 1000 to 12,000 s.c.f. of hydrogen per barrel thereof in a first lconversion zone at ya temperature from 500 to 950 F., a pressure above 500 p.s.i.g. `and an LHSV of from 0.1 to 4.0 with a catalyst comprising at 'least one hydrogenating component selected from the Group VI metals and compounds of Group VI metals and at least one hydrogenating component selected from the Group VIII Imetals and compounds of Group VIII metals in intimate association with 'a support selected from the group consisting of silica-magnesia supports, silica-allumina supports containing less than 70 weight percent lof silica, and silica-alumirra-imfaignesia supports having a silica content less than 8O weight percent, catalyticallly hydrocracking the heavier of said fractions in a second conversion zone under conditions within the yaforesaid ranges with 1a catalyst having the aforesaid description, said heavier fraction being passed through the catalyst body in said .second conversion zone, recovering from eaoh of said zones at least one product boiling below the initial boiling point of the feed to said zone, including substantially all gasoline boiling below 400 F. produced in said zone, and passing heavier materials from each Zone to said second zone onily.

2. A process for producing gasoline and middle distillates from a hydrocarbon ifeed selected `fro-m the group consisting of petroleum distillates and petr-oleum residua boiling above 650 F., which lcomprises separating said feed into -a first fraction and a generally heavier second fraction of different boiling range, lcatalyticaly hydrocracking said rst fraction in the presence of from 1000 to 12,000 s.c.f. of hydrogen per barrel thereof in a first conversion zone at a temperature from 500 to 950 F., a pressure above 500 p.s.i.g, and an LHSV of from 0.1 `to 4.0 with :a catalyst `comprising at least one hydrogenating component selected from the Group VI metals and lcompounds of Group VI metals and at least one hydrogenating component selected ffrom the Group VIII metals and compounds of Group VIII metals in intimate iassociation with a support selected from the group consisting of silica-magnesia supports, silica-alumina supports containing less than 70 weight percent of silica, and silica- :alumina-magnesia supports having a silica content lless than 80 weight percent, yrecovering at least one product boiling below 500 F. from said first conversion zone, including substantially all .gasoline boiling below 400 F. produced in said zone, catalytic-ally hydrocracking said second fraction in the presence of from 1000 to 12,000 s.c.f. of hydrogen per barrel thereof in a second conversion zone :at a temperature from 500 to 950 F., a pressure above 500 p.s.i.g., and an LHSV of yfrom 0.1 to 4.0 with a catalyst comprising at least one hydrogenating component selected from the Group VI metals and compounds of Group VI metals and at least one hydrogenating component selected from the Group VIII metals and compounds of Group VIII metals in intimate association with ya support selected from the group consisting of silica-magnesia supports, silica-alumina supports containing less than weight percent of silica, and silicaalumina-magnesia supports having a silica content less than Weight percent, said generailly heavier fraction 'being passed through the catalyst body in said second conversion zone, recovering at least one product boiling below 550 F. from said second conversion zone, and passing to said second conversion zone -from said each of said first and second conversion zones a fraction boiling above 550 F.

References Cited by the Examiner UNITED STATES PATENTS 3/1965 Claussen et -al 208-111 3/1965 Burch 208-111

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
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US3175966 *Sep 24, 1962Mar 30, 1965Cities Service Res & Dev CoTreatment of a crude hydrocarbon oil in several stages to produce refined lower boiling products
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US3449460 *Jun 6, 1968Jun 10, 1969Bethlehem Steel CorpUpgrading of coke oven light oils
US4082647 *Dec 9, 1976Apr 4, 1978Uop Inc.Simultaneous and continuous hydrocracking production of maximum distillate and optimum lube oil base stock
US4648958 *Mar 26, 1984Mar 10, 1987Union Oil Company Of CaliforniaProcess for producing a high quality lube oil stock
US4743354 *Oct 10, 1986May 10, 1988Union Oil Company Of CaliforniaProcess for producing a product hydrocarbon having a reduced content of normal paraffins
US4743355 *Jun 2, 1986May 10, 1988Union Oil Company Of CaliforniaProcess for producing a high quality lube oil stock
US4762607 *Apr 13, 1987Aug 9, 1988Exxon Research And Engineering CompanyHydroconversion process with combined temperature and feed staging
US6113775 *Nov 19, 1998Sep 5, 2000Uop LlcSplit end hydrocracking process
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Classifications
U.S. Classification208/78, 208/110, 208/111.25, 208/111.3, 208/80, 208/111.35, 208/59
International ClassificationC10G65/00
Cooperative ClassificationC10G65/00
European ClassificationC10G65/00