US2899380A

US2899380A - Charge oil

Info

Publication number: US2899380A
Authority: US
Publication date: 1959-08-11
Anticipated expiration: 1976-08-11

Description

Aug. 11, 1959 w. c. LANNING 2,899,380

HYDROCRACKING OF PETROLEUM RESIDUUM WITH USE OF GRAVITY BED 'OF CATALYTIC PARTICLES Filed Dec. 3, 1954 CATALYST CHARGE on. 17 y 2| HOPPER FR SH HYDROGEN 2s REACTOR 25- 4 PRODUCT T11 23 22/ A i as l I I2 GASOLINE 4| 0 l FLUE GAS 9 REeEN z55 oR- 0153a. on.

42 A AIR & STEAM 34 REGENERATED 43 CATALYST HOPPER GAS o|| s TO CAT CRACKING INVENTOR. w.c. LANNING A TTORNEK William C. Lanning, Bartlesville, kla., assignor to Phillips Petroleum Company, a corporation of Delaware Application December 3, 1954, Serial No. 473,015

7 Claims. (Cl. 208-108) This invention relates to a process for the hydrogenolysis of petroleum residues and other heavy hydrocarbons.

Gasoline is by far the most important product of the petroleum industry. The primary goal of the petroleum refiner is to produce the maximum quantity of gasoline of highest possible quality from a barrel of petroleum at the least possible cost. The most important step forward towards this goal in recent years was the introduction of catalytic cracking. This process affords good yields of gasoline of considerably improved quality and is now in wide commercial use throughout the country. It is generally'difiicult or impractical to effect the catalytic cracking of heavy hydrocarbon fractions, such as topped or reduced crude, or other residual fractions, because of excessive coking and contamination of the catalyst, as well as excessive production of low grade products. Usually hydrocarbon crudes or residual fractions are subjected to vacuum distillation, propane deasphalting, or other suitable processes to remove alphaltenes and coke forming constituents, whereby a relatively light gas oil is obtained for charging stock to a catalytic cracking unit.

Destructive hydrogenation of high boiling hydrocarbons is well known. Conversion of such materials can be satisfactorily accomplished in this manner, but it requires rather high pressures of the order of 3000 p.s.i. and above. sons for employing low pressures. Also, the products obtained by such high pressure treatment are usually of inferior quality. Attempts to use lower pressures, in general, have been unsatisfactory mainly due to the fact that carbon deposition is markedly increased. The hydrogenolysis process has usually been carried out in a static bed reactor but this method of operation has not proved entirely satisfactory when attempting to obtain complete conversion of high boiling hydrocarbon fractions to distillate and coke. Therefore, it is a principal object of this invention to provide an economically feasible continuous process for the complete conversion of high boiling hydrocarbons by hydrogenolysis into lower boiling products and coke at moderately low pressures. Another object is to provide a hydrogenolysis process for completely converting petroleum residues to lighter hydrocarbon fractions and coke. It is also an object of the invention to provide a process for converting heavy hydrocarbons to lighter fractions in two stages in a single reactor wherein more severe conditions favorable to converting the heavier material flowing from the first stage are maintained in the second stage. Other objects will become apparent from a consideration of the accompanying disclosure.

This invention is concerned with an improved process for the hydrogenolysis of petroleum residues to obtain complete conversion of the residue to distillate and coke in a moving bed reactor, said improvement comprising passing a preheated charge oil and an H -containing There are compelling economic reanited States Patent 0 r 2,899,380. Patented Aug. 11, 1959 i ing a vaporous effluent produced in both sections at some intermediate point in the reactor, removing the coke covered catalyst from the reactor, and regenerating and retuming the regenerated catalyst to the reactor.

According to the invention, a hydrogenolysis process is carriedout using, a granular or pelleted catalyst that flows downwardly in the reactor by gravity and forms a solid moving bed of catalyst therein, coke-covered catalyst being continuously withdrawn from the reactor, regenerated, and returned to the reactor. Heated charge together with hydrogen is introduced at the top of the reactor and moves concurrently with the catalyst through the upper. portion of the reactor. The vaporous products produced in the upper portion of the reactor along with a lesser amount of vaporous products produced in the lower portion of the reactor are removed at some intermediate point in the reactor. The catalyst continues moving downwardly through the lower portion of the reactor concurrently with the unconverted liquid charge against a counter-flow of heated hydrogen, which is introduced at a point in the lower portion of the reactor, preferably at the bottom. Hydrocarbon vapors are formed during the countercurrent flow and are removed at an intermediate point in the reactor with vaporous products and hydrogen initially present in the upper portion of the reactor, by stripping action of the countercurreutly flowing hydrogen. The remainder of the liquid charge, not converted to vaporous products, is converted .to coke and removed with the catalyst to the regenerator. Thus it can be seen that the process of the invention utilizes the catalyst very efficiently to obtain complete conversion of the residuum to distillates and coke, the more. refractory residuum being converted at more severe conditionswhich would not be desirable in a one-stage process.

Hydrogenolysis of the unvaporized portion of the charge stock takes place in the lower section of the reactor to produce high quality distillates simultaneously with hydrogenolysis of the vaporized portion of the charge stock in the upper section of the reactor to produce gasoline and distillates. The products from 'both sections include the same fractions; i.e., normally gaseous hydrocarbons, gasoline, diesel oil, light and heavy gas oils, and coke. The properties of the corresponding fractions differ somewhat because of the difference in material being converted, but this, perhaps, is not significant since all products are combined. The significant difference is that the more refractory residuum is converted at the more severe conditions in the bottom section. Since the more refractory residuum is usually more aromatic, the products are also more highly aromatic or less paraffinic.

Examples of suitable feed stocks that can be treated according to the present invention include crude petroleum, reduced or topped crude, high-boiling tarry fractions, heavy gas oils, and other fractions. In general, the pressures utilized in the reactor may range from 200 p.s.i. to 1000 p.s.i., preferably from about 400 to about 700 p.s.i., with temperatures in the range of 650-950 F., preferably 800900 F. in the upper section of the reactor and 900-1l00 F., preferably 950-1050 F., in the lower reactor section. The maximum temperature in the lower section should be at least 50 and, preferably, at least F. higher than that in the upper sec tion to effect the required coking and conversion. The feed rates may vary widely, but are generally in the range 0505 to 4 volumes feed perhour; The total amount'of hydrogen charged to the reactor may range from: about 4000 to about 15,000 cubic feet per barrel of fresh oil charged, Examples of suitable "catalysts that may be used in the invention are nickelycobalt; and iron"as'n1eta-ls and/or oxides; nickel t ungs tate, cohaltfmolyb'date, chromium; molybdenum: and tungsten oxides or sulfides, etc; These catalysts, are generally distributed on or otherwise compositedflwith a porous carrier such asaotivated alumina, silica gel; silica-alumina cracking catalyst, etc. a a

' More complete understanding OfilIlY invention will be obtained byreference to' the accompanying diagrammatic drawing which presents a preferred arrangement" of-apparatus and flow in accordance with the invention. The apparatus in which theprocessis-carriedoutconr sists of areactorlO; and a regenerator 11 which maybe built into a' single tower '1-2; Catalystis fed by gravity from an, upper-catalyst hopper 13' by 'line'l4 into catalyst distributinghead'lS. which comprises avcatalyst'feedi tray 16. A. petroleum residue charge stock' in line 11, such' as-a reduced crude oil having an initial boiling point in the range of 700-850" F. with fresh and .recycle hydrogen supplied through

lines

18 and 19 is passed to preheater'20, heated to 'a temperature in the range of .825 to"925 F., and passed through line 21' to the top of reactor 10. The. hydrocarbon feed, hydrogen, and catalyst pass concurrently downward through the reaction zone 10, the vaporous productand excess hydrogen being removed atan intermediate point 'inthe reactor, at gas separating means 22', and passed through line 23. to a cooler 24 and high. pressure separator 25;, An overhead stream rich in hydrogen .and containing somelight hydrocarbonsis'removed from high pressure separator 25 through line 26 for recycle to reactor 10, or for otherutilization, in part or in whole, through line 43.. Also entering reactor is the remaining portion of fresh and recycled'hydrogen supplied through

lines

18 and 27, and.

passed through. line 28, preheated in preheater 29' to a.

hydrogen are contacted in countercurrent flow, and'in.

the upper portion the flow is concurrent.

The coke coated catalyst is fed by gravitythrough line 31 into regenerator 11. Air and inert gas or superheated steam are injected into the regenerator via line 32 whereby the coke and other deposits are burnt oif the catalyst in conventional manner. Temperatures are controlled by varying the air flow and also by means, where necessaxy, of a cooling system (not shown) located within the 'regenerator. The regenerated catalyst vflows by gravity from the regenerator through a seal leg 33 to a lower catalyst hopper 34; The catalyst is picked up by a stream of flue gas'introduced into the hopper 34 by line 35', and lifted'via lift 36 to the upper catalyst hopper 13, from which the flue gas is vented through line 37, the catalyst being fed back. into the reactor.

through line 38. If desired, compressed air or a me-v chanical elevator can be used for elevating the regenerated catalyst to the upper catalyst hopper. Catalyst inlet temperature to the reactor is controlled by any suitable method such as by'regulating the gas lift temperature;

The liquid hydrocarbon products recovered from high pressure separator 25 are, passed to a fractionator 39 through line 40, wherein thisfraction is separated into alow boiling range fraction comprising gasoline removed The flue gas leaving the regenerator. is split into two streams, one being used as catalyst lift gas, and theremainder being vented per volume of catalyst by line 41, a diesel oil fraction by line 42, andalight and heavy gas oil fraction byline-43; The light and heavy gas oil fraction is a very desirable charge stock for catalytic cracking, and is preferably passed to such a unit to convert the gas oils to gasoline, fuel gas, heating oil, and coke.

Fresh catalyst may be'introduced to the system at any suitable point in the apparatus such. as in catalyst hopper 13 in conventional manner;

The following specific example is set forth to illustrate the invention and provide a better understanding thereof. A Panhandle residuum having an initial B.P. of 1050 to 1100 F. and a high-sulfur Montana topped crude having 'aninitial 3.1 .1 or about 400 F-. when subjected to hydrogenolysis in apparatus arranged substantially as in the drawing, utilizing a feed inlet'temperature of about 850 F., a cobalt molybdate catalyst supported on alumina at an inlet temperature of about 850 F., 2 volumes of charge oil per hour per volume ofcatalyst, a 2-hour residence time of catalyst in the top section of the reactor, 2000 cubic feet per hour of H per barrel of liquid feed to each section, ahydrogen feed' temperature to the lower section: of 1000 F], and. operating pressure of 500 p-.s.i.g., yield the results shown in the table. This operation requires a flow of 05' barrel per hour: of catalyst to the reactor, 2 barrels per hour of oil feed, and 4000 cubic feet per hour of H 'containing gas. There is a flow of about 0.6 barrel per hour of residual liquid oil into the lower section; whichrequires-an upflow of H gas of about 1200 cubic feet per hour. (Flow rates are expressed in barrels-per b'arrelof reactor space.)

Table Yield, Wt. Percent of Charge Panhandle Hi h-Sultur Residuum Tontaitila PP Crude v 28.2 20.1 24.8 40. 8 25.9 32.1 6. 7 1'. 6 sulfur- 2 1 Thus, by the practice of the presentinvention, residual stocks which would otherwise have to be sold as low cost heavy fuel oil, or otherwise used as, low grade heavy products; are converted to valuable catalytic cracking feed, in an economically feasible continuous process,

-which may be cracked over catalysts, without undue contamination or coke formation, to yield high octane gasoline and other valuable productsnormal to the fluid catalytic cracking operation;

Certainmodifications of the invention will become apparent tov those skilled in, theart and. the illustrative details disclosed are not to be construed as imposing unnecessary limitations on the invention.

.1. -A process for converting high boiling. hydrocarbons to lower. boiling hydrocarbons andcokeby hydrogenolysis, comprising maintaining a. gravitating-bedof hot solid particulate catalyst inalreactiou zone;.contacting said catalyst, in, concurrent flow in. the. upper section. of said reaction zone, with a stream of higher boiling hydrocarbon liquid and hydrogen under reaction conditions including a timperature in the, range ofj650 to 950 E. which convert a substantial portion of said hydrocarbons to. lower boilinghydrocarbons and leave, a substantial portion of unreacted liquidlhydrocarbon; contacting said catalyst and unreacted liquid hydrocarbon in countercurrent flow in the lower section of said reaction zone witha hot stream.

of hydrogen-containing gas under reaction conditions including a temperature in the range of 900 to 1100 F. and at least 100 F. above that maintained in said upper section so as to convert a substantial portion of said liquid hydrocarbon to lower boiling hydrocarbons and coke; and recovering a gaseous effluent from an intermediate section of said reaction zone comprising the reaction products from said upper and lower sections and free hydrogen.

2. The process of claim 1 wherein the hydrocarbon feed comprises a fraction having an initial boiling point in the range of 600-850 F.

3. The process of claim 1 including feeding 4000 to 15,000 cubic feet of hydrogen to said reaction zone per barrel of hydrocarbon feed.

4. The process of claim 1 including the steps of transferring catalyst from said lower section to a burning zone; regenerating said catalyst in said burning zone by burning the coke therefrom at a temperature above about 1000 F. but below that at which substantial deterioration of said catalyst occurs; and transferring the regenerated catalyst substantially at the temperature resulting from regeneration to the upper section of said reaction zone.

5. The process of claim 1 including the steps of recovering a normally liquid hydrocarbon fraction from said reaction products; separating said fraction into a gasoline fraction and a gas oil fraction; and catalytically cracking said gas oil fraction to hydrocarbon boiling in the gasoline range.

6. A process for converting a reduced crude oil fraction having an initial boiling point in the range of 700-850 F. to hydrocarbons boiling in the gasoline range, comprising heating said fraction to an elevated temperature and feeding same in liquid form together with hydrogen to the upper end of a bed of hot solid particulate catalyst gravitating thru a reaction zone, the temperature of said catalyst and the feed being regulated so as to maintain a reaction temperature in the upper section of said reaction zone in the range of 650-950" F. and efiect mixed liquid and vapor phase conversion of a substantial portion of said feed to lower boiling hydrocarbons including those in the gasoline range, a remaining portion in liquid form passing to the lower section of said zone; feeding a hot stream of hydrogencontaining gas at an elevated temperature and in suflicient quantity to the lower portion of said lower section to maintain therein a reaction temperature in the range of 900 to 1100 F. and at least F. higher than the temperature maintained in said upper section so as to substantially completely convert said remaining portion to lighter hydrocarbons and coke; withdrawing an effluent from an intermediate section of said zone comprising reaction products and hydrogen from both said upper and lower sections; and recovering hydrocarbons boiling in the gasoline range from said eflluent.

7. The process of claim 6 including the steps of withdrawing coked catalyst from the lower end of said lower section and transferring same to a burning zone; burning coke from said catalyst at a temperature below that at which substantial deterioration of the catalyst occurs by controlling the flow rate of oxygen to the burning zone; and transferring the hot regenerated catalyst to said upper section.

References Cited in the file of this patent UNITED STATES PATENTS 2,322,863 Marschner et a1. June 29, 1943 2,356,611 Peters Aug. 22, 1944 2,689,821 Imhoff et a1. Sept. 21, 1954 2,744,053 Kay et a1. May 1, 1956 2,793,170 Stiles et a1. May 21, 1957

Claims

1. A PROCESS FOR CONVERTING HIGH BOILING HYDROCARBONS TO LOWER BOILING HYDROCARBONS AND COKE BY HYDROGENOLYSIS, COMPRISING MAINTAINING A GRAVITATING BED OF HOT SOLID PARTICLE CATALYST IN A REACTION ZONE; CONTACTING SAID CATALYST IN CONCURRENT FLOW IN THE UPPER SECTION OF SAID REACTION ZONE WITH A STREAM OF HIGHER BOILING HYDROCARBONS LIQUID AND HYDROCARBON UNDER REACTION CONDITIONS INCLUDING A TEMPERATURE IN THE RANGE OF 650 TO 950*F. WHICH CONVERT A SUBSTANTIAL PORTION OF SAID HYDROCARBONS TO LOWER BOILING HYDROCARBONS AND LEAVE A SUBSTANTIAL PORTION OF UNREACTED LIQUID HYDROCARBON; CONTACTING SAID CATALYST AND