US3378482A

US3378482A - Controlled hydrocracking

Info

Publication number: US3378482A
Application number: US578388A
Authority: US
Inventors: Elliott P Doane
Original assignee: Phillips Petroleum Co
Current assignee: Phillips Petroleum Co
Priority date: 1966-09-09
Filing date: 1966-09-09
Publication date: 1968-04-16
Anticipated expiration: 1985-04-16

Description

United States Patent Oflice 3,378,482 CONTRQLLED HYDROCRACKING Elliott P. Doane, Bartlesville, 014121., assignor to Phillips Petroleum Company, a corporation of Delaware Continuation-impart of application Ser. No. 399,362,

Sept. 25, 1964. This application Sept. 9, 1966, Ser.

3 Claims. (Cl. 208108) ABSTRACT OF THE DISCLOSURE Process and apparatus for the controlling of distillate to gasoline ratio in the product obtained by the hydrocracking of gas oil wherein the desired ratio of gasoline to distillate is achieved by utilization of either cocurrent or countercurrent hydrogen flow.

This application is a continuation-impart of my copending application Ser. No. 399,362, filed Sept. 25, 1964, now abandoned.

This invention relates to hydrocracking heavy gas oil. More specifically, this invention relates to a method and apparatus for controlling the hydrocracking of oil so as to obtain and vary as required a desired ratio between the gasoline and distillate produced therefrom.

In conducting an integrated refining operation, it is highly desirable to have a flexible operation which would allow for producing maximum quantities of those products required due to seasonal demand while at the same time minimizing the production of those products which are not in such demand so as to avoid the expense of storing same. Thus, for example, in the hydrocracking of oils it would be desirable to seasonably alter the ratio of gasoline to distillate so as to achieve a distillate-to-gasoline ratio in line with consumer demand.

Accordingly, it is an object of the present invention to provide a method for achieving control of a hydrocracking operation so as to meet seasonal demands for the products therefrom. Another object of this invention is to provide a method for achieving control of the distillateto-gasoline ratio in the hydrocracking of virgin or cracked heavy gas oil.

A still further object of this invention is to provide a hydrocracking unit having a controlled gasoline-distillate ratio.

A further object of this invention is to provide a method and apparatus for the control of product ratio in the hydrocracking of heavy gas oil.

Other objects, advantages and features of the invention will be apparent to those skilled in the art from the following description, the drawing, and the appended claims.

In accordance with this invention, Ihave now discovered that the ratio of distillate to gasoline can be controlled during hydrocracking of gas oils or heavy cycle oils boiling above about 600 F. by operating the cracking process with either cocurrent or countercurrent hydrogen flow. The yield of gasoline when using countercu-rrent flow of the hydrogen relative to the flow ofthe gas oil or heavy cycle oil feed is considerably higher that it is with a cocurrent hydrogen flow. In some cases the gasoline yield can be doubled by changing from cocurrent to countercurrent flow.

By determining the ratio of the output of gasoline and distillate products from the hydrocracking unit, the quantity of and path of flow of hydrogen introduced to the hydrocracking unit is regulated responsive thereto so as to produce the desired gasoline and distillate products in any particularly desired ratio. This in turn serves to render the operation more flexible, thereby overcoming the major 3,378,482 Patented Apr. 16, 1968 Broad Preferred Temperature, F 500-900 550850 Pressure, p.s.i.g 500-5, 000 1, 000-3, 000 Hz, S.e.f./bl)l. 500-12, 000 4, 500-10, 000 Gas oil, LHSV 9 0.1-10. 0 0. 2-3. 0

1 Standard cubic feet per barrel. 2 Liquid hourly space velocity.

Any of the hydrocracking catalysts known to the industry can be used in the process of my invention. For example, the active hydrocracking ingredient can be selected from the Group VI-B (Langes Handbook of Chemistry, eighth edition, pp. 56-57) oxides and sulfides and the Group VIII metals, oxides and sulfides, or mixtures thereof. Usually a Group VI-B metal oxide or sulfide is used together with a Group VIII ferrous metal, oxide or sulfide, Whereas a Group VIII metal, oxide or sulfide is frequently used alone. Exemplary of active hydrocracking ingredients that can be used are nickel, platinum, cobalt, palladium, nickel oxide-molybdenum oxide (frequently referred to as nickel molybdate), iron sulfide nickel, sulfide, cobalt sulfide-molybdenum sulfide, nickel oxide-tungsten oxide (frequently referred to as nickel tungstate), nickel sulfide-tungsten sulfide, tungsten sulfide, and the like. The active ingredient, or each of the active ingredients if there is more than one, can be present (as metal) to the extent of 0.1 to 25.0 Weight percent, preferably 1.0 to 15.0 weight percent, of the support. Quite frequently the catalyst is sulfided by treatment with a material such as car- 'bon disulfide before use. It is also possible to obtain the same effect by operating with a sulfiding material in the feed, or by both presulfiding and operating with a sulfiding material in the feed.

The invention is described particularly with reference to a silica-alumina support, but any of the known acidic supports can be used to prepare catalysts for the inventive process. Exemplary of other acidic supports are silicazirconia, silica-alumina-zirconia, silica-magnesia, silicaalumina-magnesia, silica-thoria, silica-alumina-thoria, alumina-boria and the like. The support used can optionally be treated with steam to decrease the acidity or with a halogen or halogen acid to increase the acidity.

A more complete understanding of the invention may be had by reference to the accompanying schematic flow diagram illustrating one arrangement of apparatus and flow for effecting the desired results of the invention.

As shown in the accompanying drawing, heavy gas oil or other heavy hydrocarbon feed stock is introduced from a supply source by way of conduit 2 into upright hydrocracking unit 4 having a conventional catalyst bed 6 therein. Outlet 8 is provided to remove liquid products from the hydrocracking unit. Hydrogen from hydrogen storage unit 10 is introduced by means of conduit 12 and two way motor valve 14 into either

conduits

16 or 18 and then into either the upper or lower end zone of the hydrocracking unit 4. The feed in admixture with hydrogen is hydrocracked in unit 4 to produce gasoline and distillate. Gaseous products, including unreacted hydrogen, hydrogen sulfide, ammonia, and the like, from the hydrocracking unit are removed by means of

conduits

20 or 22 and two-Way motor valve 24 and thereafter passed by means of conduit 26 into separation zone 28 from which hydrogen can be optionally recycled to storage unit 10. The 'efll-uent removed by means of conduit 8 consists essentially of gasoline and distillate products of the hydrocracking reaction. The reaction effluent of gasoline and distillate is passed by means of conduit 8 to distillation unit 30 wherein the gasoline portion is removed by means of conduit 32. Distillate is removed through conduit 34. Flow transmitter 36 is provided in conduit 32 to provide a first signal representative of the rate of flow of gasoline product from the distillation zone 30. Flow transmitter 38 is provided in conduit 34 to provide a second signai representative of the rate of flow of distillate product from the distillation Zone 30. First and second signals produced by

fiow transmitters

36 and 38 are introduced to ratio controller 40 which is preset to a desired ratio of distillate to gasoline, and which compares the received signals and issues responsive thereto a third signal representative of the difference, if any, between the desired ratio and the actual produced ratio of distillate to gasoline. Responsive to the thus produced signal, motor valves 14 and 24 are manipulated so that when the distillate/gasoline ratio produced by the hydrocracking is above that desired, generally 1.5 to 1, hydrogen from storage zone is introduced through conduit 18 into the lower zone of unit 4 and gaseous products are withdrawn through conduit 20, thus giving a countercurrent flow of hydrogen in the hydrocracking unit. Conversely, when the distillate/ gasoline ratio is below that desired, valves '14 and 24 are actuated so that hydrogen from storage zone 10 is introduced through conduit 16 into the upper zone of unit 4 and gaseous products are withdrawn through conduit 22, thus giving a cocurrent flow of hydrogen to the hydrocracking unit. By operating in the above manner, sufiicient hydrogen is provided to the hydrocracking unit in either a cocurrent or countercurrent direction to provide .any desired ratio of distillate to gasoline.

The process and apparatus of this invention are particularly suitable for producing and maintaining a distillate to gasoline ratio value of either above or below 1.5 to 1.

The following example Will further illustrate my invention.

EXAMPLE A Gulf Coast 650+F atmospheric gas oil was utilized in a series of runs to demonstrate the present invention. The catalyst was a nickel molybdate prepared by impregnating /8-l1'1Ch pellets of silica-80 alumina with sufficient aqueous ammonium molybdate solution to give a molybdenum content of 7.1 weight percent, drying the composite at about 220 F., and calcining it at about 900 F., impregnating with sufficient aqueous nickel nitrate solution to give a nickel content of 1.8 weight percent, drying the composite at about 220 F. and calcining it at about 1100 F. The catalyst was reduced and sulfided before use by heating it in nitrogen to 600 F., pressuring to 2000 p.s.i.g. with hydrogen and continuing hydrogen flow for 4 hours, and then passing over the catalyst normal hexane containing about 3 weight percent carbon disulfide at 2000 p.s.i.g. and 0.5 LHSV for 4 hours. The two modes of operation were compared at a temperature of 760 F., a pressure of 2000 p.s.i.g., a hydrogen flow of about 6000 standard cubic feet per barrel, and a gas oil liquid hourly space velocity of 0.25. The following results were obtained:

Ha Flow Cocurrent Countercurrent Yield, wt. percent:

C1-C4 2.0 3. 5 05-350" F. (Gasoline) 12.5 22.5 350-650 F. (Distillate) 35.5 24. O Distillate/Gasoline Ratio 2. 8 1. 1

I claim:

1. In a hydrocracking process wherein a gas oil is passed downwardly through a bed of supported hydrocracking catalyst in a hydrocracking zone maintained under hydrocracking conditions in the presence of hydrogen, an efiiuent is withdrawn from the lower end of said hydrocracking zone containing a gasoline fraction and a distillate fraction, and wherein the resulting gasoline fraction and distillate fraction are separated and separately recovered as products of the process, the improvement which comprises measuring the rate of How of said gasoline fraction and said distillate fraction so as to obtain the ratio of the gasoline fraction and distillate fraction produced, thereafter obtaining a signal representative of the difference between a predetermined ratio of distillate to gasoline and the ratio of distillate to gasoline being produced in said hydr-ocracking zone and responsive to said signal alternately and respectively introducing the hydrogen to said hydrocracking zone so that the hydrogen will pass upwardly through said hydrocracking catalyst in countercurrent contact with said gas oil in an amount sufiicient to produce a distillate to gasoline ratio of less than 1.5 to 1 in the converted gas oil while recovering hydrogen and light gases from the upper portion of the hydro'cracking catalyst bed and introducing the hydrogen to said hydrocracking zone so that the hydrogen will pass downwardly through said hydrocracking catalyst in cocurrent contact with said gas oil in an amount sufficient to produce a distillate to gasoline ratio of greater than 1.5 to 1 in the converted gas oil while recovering hydrogen and light gases from the lower portion of the hydrocracking catalyst bed.

2. A process according to claim 1 wherein said gas oil boils above 600 F., the temperature within said bed is in the range of 500 to 900 F. and the pressure is in the range of 500 to 5000 p.s.i.g.

3. A hydrocracking unit comprising in combination (a) an elongated generally upright reaction vessel containing a bed of hydrocracking catalyst therein;

(b) distillation means to separate gasoline and distillate produced in said reaction vessel;

(c) first conduit means communicating with a source of gas oil and the upper end of said reaction vessel to introduce gas oil into said reaction vessel;

((1) second conduit means communicating with the lower end of said reaction vessel and said distillation means to remove efliuent from the lower end of said reaction vessel and introducing same to said distillation means;

(e) a source of hydrogen;

(f) a first two-position valve means adapted to be responsive to a signal from a ratio-controller means;

(g) third conduit means communicating with said source of hydrogen and said first two-position valve means;

(h) fourth conduit means communicating with said first two-position valve means and the lower end of said reaction vessel;

(i) fifth conduit means communicating with said first two-position valve means and the upper end of said reaction vessel;

(j) accumulating means for gaseous effluent from said reactor vessel;

(k) second two-position valve means adapted to be responsive to a signal from a ratio-controller means;

(1) sixth conduit means in communication with said second two-position valve means .and the lower end of said reaction vessel;

(in) seventh conduit means in communication with said accumulating means and said source of hydrogen;

(n) eighth conduit means in communication with said second two-position valve means and the upper end of said reaction vessel;

(0) ninth conduit means in communication with said second two-position valve means and said accumulating means;

said first and second two-position valve means in a first position connecting said source of hydrogen to said fifth conduit and said accumulating means to said sixth conduit means;

said first and second two-position valve means in a second position connecting said source of hydrogen to said fourth conduit means and said accumulating means to said eighth conduit means;

(p) tenth conduit means in communication with the upper end of said distillation means to remove an overhead efiiuent therefrom;

(q) eleventh conduit means in communication with the lower end of said distillation means to remove a distillate effluent therefrom;

(r) twelfth conduit means communicating with the lower end of said distillation means and said first conduit means to remove a bottoms effiuent from said distillation means and recycle same to said reaction vessel;

(s) first flow transmitter means positioned in said tenth I conduit means so adapted to provide a first signal representative of the rate of flow of gasoline from said distillation means;

(t) second flow transmitter means positioned in said eleventh conduit means so adapted to provide a second signal representative of the rate of flow of distillate efiiuent from said distillation means;

(u) ratio controller means adapted to receive said first and second signals and to produce a third signal responsive thereto to said first and second two-position valve means whereby said valve means are maintained in one of said first and second positions.

References Cited UNITED STATES PATENTS 2,602,771 7/ 19521 Munday et al 208-159 3,186,935 6/1965 Vaell 208108 3,234,121 2/1966 MacLaren 208112 3,256,176 6/1966 Mills 208112 3,268,438 8/1966 Scott et al 208-89 ABRAHAM RIMENS, Primary Examiner.