US2771406A

US2771406A - Method and apparatus for supplying liquid charge to hydrocarbon reactors

Info

Publication number: US2771406A
Application number: US357292A
Authority: US
Inventors: Frederick E Ray
Original assignee: Socony Mobil Oil Co Inc
Current assignee: ExxonMobil Oil Corp
Priority date: 1953-05-25
Filing date: 1953-05-25
Publication date: 1956-11-20
Anticipated expiration: 1973-11-20

Description

Nov. 20, 1956 F. E. RAY ,7

METHOD AND APPARATUS FOR SUPPLYING LIQUID v CHARGE TO HYDROCARBON REACTORS Filed May 25, 1953 5 Sheets-Sheet 1 Nov. 20, 1956 F. E. RAY 2,771,406

METHOD AND APPARATUS FOR SUPPLYING LIQUID CHARGE TO HYDROCARBON REACTORS Filed May 25, 1953 5 Sheets-Sheet 2 INVENTOR. PRIME/(k 5. RA)

" WWW AGENT Nov. 20, 1956 F. E. RAY 2,771,406

METHOD AND APPARATUS FOR SUPPLYING LIQUID CHARGE TO HYDROCARBON REACTORS Filed May 25, 1953 5 Sheets-Sheet 5 IN VEN TOR. IREDER/CK 5.164)

Aanv'r Nov. 20, 1956 F. E. RAY 2,771,406

METHOD AND APPARATUS FOR SUPPLYING LIQUID CHARGE TO HYDROCARBON REACTORS Filed May 25 1953 5 Sheets-Sheet 4 FHA 56 JEPARA r02 INVENTOR. Ffi'OER/CK 5. RA)

AGENT Nov. 20, '1956 F. E. RAY 2,771,406

METHOD AND APPARATUS FOR SUPPLYING LIQUID CHARGE TO HYDROCARBON REACTORS Filed May 25, 1953 5 Sheets-Sheet 5 INVENTOR. Rum/(x a. my

United States Patent METHOD AND APPARATUS FOR SUPPLYING LIQUID CHARGE T0 HYDROCARBON RE- ACTORS Frederick E. Ray, Glen Rock, N. 1., assignor to Socony Mobil Oil Company, Inc., a corporation of New York Application May 25, 1953, Serial No. 357,292

13 Claims. (Cl. 196-52) This invention is concerned with a method and apparatus for supplying a hydrocarbon charge, especially the liquid portion thereof, to a hot contact material bed suited to effect the conversion of the hydrocarbon charge. Particularly, this invention is concerned with supplying liquid hydrocarbon charge to a reaction bed of contact material existing at a temperature above the temperature at which there is substantial coke formation in the liquid charge, in a manner which avoids excessive formation of coke from the liquid before it reaches the contact material bed.

Typical of the processes to which this invention applies is the catalytic conversion of a high boiling hydrocarbon charge, supplied at least in part as a liquid, to lower boiling gaseous products by contacting the charge with a moving bed of granular adsorbent catalyst. Other exemplary processes include the catalytic dehydrogenation, polymerization, isomerization, alkylation, and the like, of liquid or mixed phase hydrocarbons in the presence of a solid catalyst and the thermal coking, cracking, visbreaking, and the like, of liquid or mixed phase hydrocarbons in the presence of an inert solid.

In processes where the contact material is catalytic in nature, it may partake of the nature of natural or treated clays, bauxite, activated alumina, or synthetic associations of silica, alumina, magnesia, or combinations thereof, to which certain metallic oxides may be added in small amounts for specific purposes. When the contact material is inert in character, it may partake of the form of refractory materials, such as zirkite, corhart or mullite or particles of quartz, fused alumina or coke, or it may partake of the form of stones or metallic particles or balls. Where the process is one wherein the contact material is maintained in the reaction zone as a fixed bed or as a moving mass of particles, it should generally be within the size range of about 1 inch to 100 mesh, and preferably 4 to 20 mesh by Tyler Standard Screen Analysis. Where the contact material exists as a fluidized bed, it should have a size generally falling within the range about 100 to 400 mesh.

In processes of the aforementioned types, it is frequently necessary to maintain the contact material reaction bed at a temperature above the temperature at which the liquid portion of the hydrocarbon charge undergoes substantial thermal conversion. Thus, one of the most pressing problems in this field is to provide a system for supplying the liquid to the reaction bed without the rapid formation of coke on the metal parts of the apparatus supplying the liquid charge which lie within the hot reaction zone. This problem becomes particularly acute when it is necessary or desirable to submerge or embed the liquid feed discharge apparatus in the contact material reaction bed. A situation of this type occurs in a recently proposed liquid feed system for conversion processes utilizing a moving mass of granular contact material. In this system the liquid is injected into a high velocity, substantially compact stream of contact material which exists at a temperature well above the temperature when it is embedded in the hot contact material, the 7 liquid therein will naturally rise in temperature to some thing approaching the contact material temperature. This will result in the rapid formation of carbonaceous material or coke which will quickly plug up the passages through which the liquid passes from the manifold. This in turn requires a shut-down of the unit for cleaning of the manifold.

A major object of this invention is to provide a method and apparatus for supplying liquid hydrocarbons which overcomes the above-described difiiculties.

Another object of this invention is to provide a method and apparatus for supplying liquid hydrocarbons to a reaction bed of contact material without rapid cake formation on the portions of the supply apparatus lying within the reaction zone.

These and other objects of the invention will be apparent from the following discussion of the invention.

Broadly, this invention deals with supplying a liquid hydrocarbon charge to a hydrocarbon reaction zone maintained at an elevated temperature and having a contact material reaction bed therein. A confined liquid plenum space is maintained within the reaction zone and liquid charge is supplied to one side of this space. A portion of the liquid charge is passed from the plenum space into the contact material bed while the remaining portion is removed from the opposite side of the plenum space and heat extracted therefrom. This portion, together with additional charge, is then returned to the plenum space. The amount ofheat extracted and the residence time of the liquid within the manifold space are controlled so as to maintain the liquid in the plenum space below the temperature at which carbonaceous material would form from the liquid in the plenum space.

This invention will be best understood by referring to the attached drawings, of which A Figure 1 is an elevational view of one system capable of operation according to this invention, applied to a hydrocarbon conversion system employing a moving mass of granular contact material,

Figure 2 is a vertical sectional view'of the upper section of the reactor of Figure 1,

Figure 3 is a sectional view along line 3-3 of Figure 2,

Figure 4 is a sectional view of*one form of liquid manifold which may be used in this invention,

Figure 5 is an elevational view of another system for supplying liquid charge to a reaction zone according to, this invention. 5

Figure 6 is an elevational view, partially in section, of the upper section of a hydrocarbon reactoremployihg another form of this invention, and

Figure 7 is a sectional view along line 77 of Figure 6.

All of these drawings are diagrammatic in form and like parts in all bear like numerals.

Turning now to Figure 1, there is shown therein the process for charging a reduced crude charge to a catalytic hydrocarbon reactor. Such charge stocks contain heavy residual materials, such as tars, asphalts, salts, and the like, which it is undesirable to pass into the hydrocarbon conversion zone. In Figure 1, the reduced crude charge is passed by means of a conduit 10, through a furnace or Patented Nov. 20, 1956' 3 other heater 11, wherein the charge is heated to a temperature below the temperature where thermal decomposition begins but sufilcient to vaporize substantially all f the hydrocarbons therein which will vaporize below of about 800 F. This vaporized charge may be supplied to the reactor at either of two alternate levels, as is described hereinbelow, through conduit 16 or conduit 17 extending from conduit 14. The pressure in separator 13 must be sutficient to force the vaporized charge from the separator into the reactor. For the normal commercial installation, about 10 to 15 pounds per square inch gauge is adequate. The separator bottoms which contain the heavier hydrocarbons, plus the tar, are removed from separator 13 through conduit 18 and passed thereby into vacuum distillation tower or zone 19. If desired, a portion or all of the separator bottoms may be heated before entry to the vacuum tower by by-passing all or a portion through heater 20 via pipes 21 and 22. The pressure in the vacuum tower 19 is maintained at a sufficiently low level to efiect vaporization of most of the heavy hydrocarbons, for example, 2 to pounds per square inch absolute. Thes heavy hydrocarbons pass overhead through conduit 23 and are condensed by condenser 24 and then supplied as a liquid to run-down or surge tank 25. The tar is removed as bottoms from the vacuum tower through conduit 26. The vacuum tower 19, conduit 23 and run-down tank 25 are all maintained under the desired reduced pressure by means of an ejector 27 or other suitable means connected to the upper end of tank 25 by conduit 28. The condensed hydrocarbons in tank 25 constitute the liquid hydrocarbon charge for the reactor 15 and constitute typically about twenty percent of the total charge to the reactor. This liquid charge is pumped from the bottom of tank 25 through conduit 29 by pump 30. The liquid charge passes first, in normal operation, through a flow measuring device 31, such as an orifice. A flow rate controller 32 is connected to device 31 and operates a flow control valve 33 in line 29 to maintain the desired rate of liquid charge flow to reactor 15. A by-pass line 34 is provided around control valve 33 with valve 35 thereon. This bypass is normally notused, however. Extending from conduit 29, downstream of control valve 33, is a reactor bypass conduit 36 with valve 37 thereon. This by-pass also is not used in normal operation and valve 37 is kept closed. The liquid charge next passes through a strainer 38 where any foreign matter, such as mill scale from the piping, suspended in the liquid is removed. Downstream of strainer 38 is blow-down line 39 with valve 40, normally kept closed. The liquid charge then passes through the remainder of conduit 29 into reactor 15 and is supplied to a liquid charging device therein, which is described hereinbelow. Only a portion of the liquid charge passed through conduit 29 is injected into the contact material flowing in reactor 15. The remainder is removed from the opposite side of the reactor through a conduit 41 and returned to run-down tank 25 through conduit 42 connecting the conduit 41. A flow measuring device 43 is provided in conduit 42, which actuates a flow rate con troller 44 to control the rate of recirculation of liquid charge by means of control valve 45. The granular catalytic contact material, for example, synthetic silicaalumina catalyst, gravitates from a supply hopper (not shown) into seal chamber 46 through conduit 47. Inert seal :gas, such as steam or flue gas, is supplied to chamber 46 through conduit 48 at a rate suflicient to maintain a slightly greater pressure in chamber 46 than in the upper section of reactor 15. The rate of seal gas supply is controlled by operating control valve 49 in response to differential pressure controller 50. Contact material passes into the upper end of reactor 15 through conduit 51, then downwardly through the conversion zone of reactor 15 as a substantially compact bed. Hydrocarbon charge, supplied as liquid and vapor, passes downwardly through the bed to effect the desired conversion reaction. The products of conversion are removed through conduit 52. Suitable gas disengaging means may be used in conjunction with conduit 52 to efficiently disengage the gaseous products from the reaction bed of contact material. An inert purge gas may be admitted to reactor 15 through conduit 53 to purge the outgoing spent contact material free of adhering hydrocarbons. Spent contact material is removed from the lower section of reactor 15 through conduit 54 at a rate controlled by valve 55 to promote downward movement of contact material particles through the reaction bed of contact material at a uniform linear velocity across the horizontal cross-section of the bed. To this end, suitable bafliing may be provided in the lower section of reactor 15. The spent contact material is then reconditioned for re-use in the conversion Zone. Where the contact material has a catalytic effect on the reaction, this reconditioning will normally take the form of a controlled burning of the carbonaceous contaminants or coke deposited on the catalyst during the conversion in a manner well known in the art. Where the contact material is inert in character, the reconditioning may consist only of reheating the contact material for re-use in the conversion zone. The reconditioned contact material is then returned to seal chamber 46, from which it passes into reactor 15.

The details of the construction in the upper section of reactor 15 are shown in Figures 2 and 3, which are best considered together. Contact material conduit 51 extends into the upper end of vessel 15 and terminates so as to discharge contact material into a centrally disposed receptacle 56. Receptacle 56 is supported by a frusto-conical partition 57, which extends inwardly and upwardly from a support member 58 on the walls of the vessel 15. Extending centrally and vertically downwardly from the bottom of receptacle 56 is conduit or passageway 59 which terminates within the upper section of vessel 15 at a level below the bottom of receptacle 56. A hood 60 is attached to the lower end of conduit 59. Hood 60 has a hollow, frusto-conical upper section which attaches at its small diameter to the lower end of passageway 59 and a hollow, cylindrical lower section. The horizontal cross-sectional area of the lower section of hood 60 is substantially less than the horizontal crosssectional area of vessel 15. Hood 60 forms the upper section of a conversion chamber or zone with the main body of the chamber or zone being formed by the remainder of vessel 15 below hood 60. A bafile 61, in the shape of an inverted, hollow cone, is fixed symmetrically within the upper section of hood 60 by support members 62 extending from hood 60. The upper end of batlle 61 has a cross-sectional area amounting to a major fraction of the horizontal cross-sectional area of hood 60, so that a narrow annular passageway for contact material flow is formed between hood and battle. Spaced vertically beneath baflle 61 are vertically spacedapart ring or hoop baffles 64 in the form of hollow, inverted, frusto-conical sections. The upper ends of said bafiles enclose horizontal cross-sectional areas amounting to a major fraction of the horizontal cross-sectional area of hood 60. Baflles 64 are placed so as to maintain a narrow peripheral region of contact material flow between the bafiles and the walls of hood 60 and a central region of substantially lower velocity contact material flow within the baffles 64, as is explained hereinbelow. .Bafiles 64 are supported from bafile 62 by spacedapart support members 65. A liquid spray ring manifold or plenum chamber 66,.having a diameter greater than the diameters of the upper ends of baffles 64, is positioned within hood 60 on a horizontal plane at a level between the uppermost of bafiles 64 and bafiie 61. Details of this spray ring are described hereinbelow in connection with Figure 4. A plurality of spaced-apart orifices penetrate the underside of ring 66, through which liquid charge may be injected or sprayed into the contact material which will flow in the narrow peripheral region between. baffies 64 and the walls of hood 60. Liquid charge supply conduit 29 connects into one side of ringv 66 and liquid charge recycle conduit 41 extends from the opposite side of the ring. A cylindrical receptacle or pan 67 is positioned centrally beneath hood 60 on a horizontal plane within the upper section of vessel 15 at a level suitable to receive contact material from hood 60 before it reaches the walls of Vessel 15. Receptacle 67 has a horizontal cross-sectional area less than but approaching that of vessel 15, so that space 68 is defined between the sides of receptacle 67 and the walls of 15. A plurality of vertical contact material conduits 69 extend downwardly from the bottom of receptacle 68 to a common level within the upper section of vessel 15. Conduits for the supply of vaporized hydrocarbon charge are provided at two levels in vessel 15, conduit 16 above receptacle 67, and conduit 17 at a level below the bottom of receptacle 67 but above the lower ends of conduits 69. A distributor baffle 70 is provided in front of conduit 16.

In operation, fresh granular contact material, at av temperature suitable for the desired conversion, gravitates into vessel 15 through conduit 51 into receptacle 56. Contact-material passes downwardly from the lower section of the accumulation of contact material in receptacle 5.6 as a single, central, substantially compact stream through passage 59. This stream is expanded outwardly under the inclined surfaces of the upper end of hood 60 as a frusto-conical shaped stream. The stream, during expansion, takes this form because a substantially stagnant layer of contact material is maintained on the upper side of bafile 61'. The upper limits of, this layer are shown by lines 71. A small hole 72 is provided in the bottom of baflle 61, so that the contact material forming the stagnant layer on 61 will slowly be changed. This hole 72 should not be so large as to allow any substantial flow of contact material in relation to that flowing around the stagnant layer. Hole 72.may be eliminated, if desired. Substantially, all of the contact material supplied to the conversion zone within vessel'15 passes through this frusto-conical stream and annular passage 63, and is supplied to an area adjacent the periphery of a single, central, substantially compact, downwardly gravitating feed column or stream of contact. material maintained below baffle 61 within the lower section of hood 60. Because the hood 60 is of cross-section only a minor fraction of the cross-section of the reactor, yet carries the entire flow of contact material to the reaction bed, a peripheral region 73 of high velocity contact material flow and a central region 74- of substantially lower velocity contact material flow are formed near the lower end of the hood. Bafiles 64 act to extend these regions upwardly in the feed column in hood 60 and cause the formation of the regions at higher levels in the feed column. The formation and maintenance of these high and low velocity regions is made possible by the flow characteristics of granular solids. The contact material column or stream leaving hood 60 is expanded outwardly in free surface flow to a horizontal cross-sectional area approaching that of vessel 15. Contact material from the central region 74 passes substantially unidirectionally downwardly to form the central region of the accumulation of contact material 75 in receptacle 67. The contact material to supply the remainder of the accumulation 75 is formed by thereabove.

contact material drawn from a narrow peripheral region of the stream in hood 6%. Thus, contact material flowing in the peripheral region between the lines of internal flow 76 and the walls of hood 60 supplies all the area of accumulation 75 not lying substantially directly beneath hood 613. Contact material from accumulation 75 passes downwardly through passages 69 to supply contact material to the upper surface of a downwardly gravitating, substantially compact reaction bed of contact material 77. Contact material particles pass through bed 77 at a substantially uniform velocity across the horizontal cross-section of the bed, and therefore contact material is drawn at about an equal rate from each of uniformly spaced conduits 67 and from accumulation 75 Therefore, the How of contact material through each unit of horizontal cross-sectional area of accumulation 75 will be the same. Hood 60, and therefore the feed stream or column therein, has a horizontal cross-sectional area amounting to only a small or minor fraction of the horizontal cross-sectional area of the accumulation 75 and of vessel 15 and reaction bed 77. Therefore, the central area of accumulation 75, which is supplied by the large central region of the feed column in hood 60, will carry only a small or minor fraction of the total contact material flow to bed 77; on the other hand, the narrow peripheral region 73 of the feed column supplies the major portion of accumulation 75 and bed 77, and therefore the velocity in region 73 will be substantially higher than in region 74 and more of the contact material will pass through region 73 than region 74. It will be noted that line 76, which defines the area of the feed column in hood 60 supplying the outer area of accumulation of contact material 75, slopes inwardly away from the walls of'hood 60, so that area 73 increases the further it is removed from the bottom of the feed column. As the area increases the velocity decreases; therefore, where the dimensions of the hood require it, baffles 64 are so placed that at succeedingly higher levels they again narrow the peripheral region 73 so as to maintain it generally below 8 inches in width and preferably within the range 3.5 to 6 inches in width, thus maintaining the high velocity in region 73 at higher levels in the feed column. A new flow pattern line 78 is formed with each battling closer to the walls of hood 60 than the one below. Liquid hydrocarbon charge is supplied to spray manifold or ring 66 by means of passage 29. Spray ring 66 is at a level substantially above the lower end of hood 6i) and the feed column therein. Liquid charge supplied through 29 is injected into high velocity region 73 of the feed column by means of the orifices in the underside of ring 66. This method of supplying liquid to the reaction bed by injection into a compact, high velocity stream of contact material is the subject of claims in U. S. patent application Serial No. 311,286, filed September 24, 1952.

If spray ring 66 were simply lfed liquid on one side, the liquid on the side opposite the feed point would remain relatively stagnant and would soon approach the temperature of the contact material stream within hood 60, which temperature is above the temperature at which substantial and rapid formation of coke from the liquid occurs. This coke would most readily form in the onfices through which liquid passes from the manifold and result in plugging of the orifices requiring a shut-down for cleaning. By this invention, such rapid formation of coke is prevented. Only a portion of the liquid charge supplied through passage 29 is injected into the contact material stream. The remainder is removed through passage 41 and returned to surge tank 25, as shown in Figure 1, so that there is no stagnant liquid in the manifold. In the tank the recycle liquid is mixed with cooler liquid from vacuum tower 19 to effect a cooling of the recycle stream. Condenser 2 5 cools the stream from the vacuum tower to a temperature such that when the liquid in this stream is mixed with the recycle stream,

the resulting temperature will be sufficiently low at the particular residence time of liquid in the manifold to maintain the liquid within ring manifold 66 below the temperature at which substantial and rapid coke formation will occur. The temperature to which the stream in passage 23 should be cooled will depend upon the particular charge stock, the quantity of recycle oil that passes through the manifold and the velocity and residence time of the oil which is in the manifold.

The liquid injected into region 73 from ring manifold 66 mixes with the large amount of contact material in this region. Because of the high temperature of this contact material, typically about 1030 F., the liquid vaporizes and is partially converted to vapors as it passes downwardly with the contact material. Vapors so formed expand into region 74, which is of relatively larger crosssection, so that there is no disruption of contact material flow through the feed stream. The vapors thcn expand into the accumulation of contact material 75, from which they pass into the upper end of bed 77, mainly by passing out of the open upper surface of accumulation 75, and then through space 68 into bed 77. Some vapors may also pass downwardly through conduits 69. Vaporized hydrocarbon charge may be supplied at either or both of two levels through conduits l6 and 17.

The use of receptacle 67 with a plurality of pipes 69 therein, which are spaced apart within a critical distance, has the effect of avoiding the creation of large temperature gradients across the reaction bed, due to cross-flow of cool vapor and hot contact material. This development is described and claimed in U. S. patent application Serial No. 338,774, filed February 25, 1953.

The term contact material bed is used herein not only as including an accumulation like '77, which forms the reaction bed proper, but also including an accumulation like 75 and the feed stream in hood 60. Thus, ring mani fold 66 may be said to be embedded in the reaction bed in Figure 2.

The construction of one suitable type of liquid hydrocarbon manifold or confined plenum space is shown in Figure 4, which is a sectional view of the spray ring 66 of Figures 2 and 3. This spray ring is made up of a central circular pipe ring 79 having a plurality of spaced apart orifices 80 through its underside. Orifices 80 are olfset from the vertical by an angle such that when the ring is embedded in flowing contact material, some of the contact material will flow directly over the area adjacent orifices 80 to scrub oif any coke which may accumulate there. The wall thickness of pipe 79 around orifices 30 is reduced, so that the depth of orifices 80 is reduced. Thus, should any coke form in orifices 80, the coke plug therein will be of relatively little thickness and may be easily eliminated by periodical burning out or reaming out. A ring-shaped receptacle 81 is around pipe 79. Receptacle 31 is of greater lateral dimensions than ring 79, so that a space 82 is defined between pipe 79 and the walls of receptacle 8R. Receptacle 81 has a bottom which fits tightly to pipe 79 at a level above that of orifices 8t and receptacle 31 extends upwardly to a level adjacent the top of ring 79. When the spray ring is embedded in flowing contact material, a stagnant layer of contact material will accumulate in space 82, within receptacle 81, around pipe 79, to insulate the liquid flowing in the pipe from the hot contact material flowing around it. The present invention of the recycling of a substantial part of the liquid flowing in the manifold for heat extraction acts to minimize the formation of coke within pipe 79 and plugging of orifices 80. However, such coke formation and plugging may still occur over long periods of time, so that provision is made to burn coke from the spray ring while the reactor continues to operate on vapor charge.

This system is best illustrated by considering Figures 1 and 4 together. When substantial coking in orifices 80 and elsewhere in pipe 79 has occurred, the flow of liquid charge to the reactor is stopped by closing valve 83 in liquid feed line 29 and opening valve 37 in by-pass line 36.

Valves

84 and 85 in recirculation line 42 are also closed. First, an inert purge gas, such as steam, is supplied to ring 79 by passing steam in through conduit 86, from which it flows into conduit 87 and then into conduit 29 and through that conduit into spray ring 79. The steam and hydrocarbons, after passage through the ring, are removed through conduit 41 and pass into conduit 42, from which they pass out through blow down line 88. After the ring is free of hydrocarbons, an air-steam mixture, preferably heated to 850-900 F., is supplied to ring 79 in controlled proportions to burn out the coke therein, air entering through conduit 87 and mixing with steam from conduit 86 and the mixture passing into conduit 29 and then into ring 79. The air acts to burn the coke in ring 79 and orifices 80, while the steam absorbs the l eat produced by the burning. Preferably, the air-steam mixture is supplied for half the required time to conduit 29 and the other half to conduit 41 by passing the mixture around through pipe 89. This promotes equal burning on both sides of the ring. During this entire operation, vaporized charge may continue to be processed within reactor 15, since the air-steam mixture may flow into the reactor and combine with the hydrocarbon vapor therein without hazard. After the burning is completed, the spray ring is again purged with steam and then the flow of liquid charge to the ring is restored.

Both the system for insulating the manifold with stagnant contact material and the system for burning out coke accumulations are described and claimed in U. S. patent application Serial No. 311,286, filed September 24, 1952.

Another arrangement capable of operation, according to this invention, is shown in Figure 5. This system will find particular application where the hydrocarbon charge has already been deasphalted by some other process, such as by solvent extraction. The hydrocarbon charge is heated in heater 82 to a suitable temperature to flash off a vaporizable fraction at the pressure maintained in phase separator 84, and is then passed through conduit 83 into phase separator 84, wherein a portion of the charge vaporizes. The vapor fraction passes overhead through line 14 and into reactor 15. The liquid fraction of the charge is removed through passage 85, passed through strainers 86 and then into a liquid-distributing manifold (not shown) within reactor 15. A portion of the liquid is injected into the reaction bed in the reactor, while the remainder is removed from the opposite side of the manifold through passage 87 and returned thereby to the phase separator. The liquid within the manifold is maintained below the temperature at which coke rapidly forms by suitable extraction of heat in one of several possible ways. The temperature to which heater 82 heats the incoming charge may be controlled, so that upon mixing with the recycle oil from passage 87, a suitably low temperature will be achieved. Alternatively, the recycle oil may be cooled, by passage through cooler 88, suflicient to arrive at the desired temperature. A third possibility is to pass the liquid charge stream, made up of fresh and recycle oil, through cooler 89 immediately before passage to the reactor and thereby arrive at the required temperature to avoid rapid coking in the manifold. Any one of these methods of cooling, or any combination of them, may be used in this invention. The degree of cooling required will again depend on the residence time of liquid in the manifold.

Figures 6 and 7 show a different form of liquid manifold which may be used in connection with this invention. Here, granular contact material gravitates through passage 51 and fills a hood 88 of substantially less cross section than the reactor. Contact material gravitates from within the hood to supply reaction bed 77. A liquid charge manifold 89 is situated within the upper section of hood 88. The manifold consists of a series of connected U-shaped bends extending across the hood and having a plurality of spaced-apart orifices 90 through their undersides. Liquid hydrocarbon charge is supplied to one end or side of the manifold through passage 29 and a portion thereof removed from the oppositeend or side through passage 41. A portion of the liquidsupplied is injected into the contact material stream within hood 88 through openings 90. The contact material stream exists at a temperature substantially above the thermal conversion temperature of the liquid, so that the liquid is vaporized and cracked as it. flows downwardly with the contact material. Vapors so formed pass into a plenum space 91, above reaction bead 77, through openings 92 in the Walls of hood 8.8. Thus, pressure, build-up within the hood is avoided. The vapors then pass from space 91 into reaction bed 77. Baflies93 are positioned so as to prevent contact material frompassing through openings 92. The liquid in manifold 89 is maintained below the temperature of rapid coke formation in the manner previously described.

The temperature at which the oil within the liquid manifold in the reactor should be maintained, will vary with the particular stock being processed, and will depend on such factors as the carbon content or residue of the charge, its molecular weight, boiling range, carbon to hydrogen ratio and type (as expressed by the U. 0. P. characterization. factor, for example). Thus, where the liquid. charge fraction is a heavy gas oil cracking stock, which is substantially free of tar and asphaltic residue and boils substantially above 800 F., the temperature of the liquid oil in the manifold should be maintained below about 700 F. and usually in the broad range about 400 to 700 F., and preferably about 500 to 650 F. For a similar stock containing a substantial amount of light gas oil, for example, about fifty per cent gas oil boiling Within the range 500-850 F., a temperature as high as 750 F. might be tolerated within the'manifold. For a stock consisting almost entirely of gas oil boiling Within the range 450850 F., a temperature as high as 850 F. in the liquid manifold might be satisfactory. On the other hand, where the charge stock is a crude residuum, the manifold temperature should be below 500 F. and frequently within the range 250 400 F.

The various parts of the improved apparatus of this invention may take many other widely different forms than those shown in the attached drawings. For example, while the reactor has been shown as circular in crosssectional shape, it may take any other desired shape, such as rectangular, hexagonal, etc; Oil may be distributed from the manifold through a plurality of nozzle or spray devices or pipes rather than using orifices.

While the manifold has been shown embedded in a compact contact material existing at a temperature above. the temperature at which coke is formedrapidly from the liquid, this invention is equally applicable Where the manifold is maintained above the bed within the reaction zone or housing containing the bed and where the bed is fluidized and the manifold is within the bed or above it in the reaction zone or housing. The manifold may also be of any desired shape.

The temperature of the liquid within the manifold will depend upon the temperature at which it is supplied to the manifold, the temperature of the surrounding reaction zone, the character of the charge and the residence time of the liquid in the mainfold. Concerning this latter, it is obvious that regardless of the temperature at which the liquid is supplied to the manifold, if it remains in the manifold for too long a time, it will rise to a temperature at which substantial coke is formed. Thus, for any given charge stock, the temperature of the liquid supplied to the manifold and the residence time of liquid in the manifold should be controlled in conjunction with each other to maintain the temperature of liquid in the manifold below the temperature of substantial coke formation. Obviously, the lower the temperature of supply of liquid to the manifold, the longer the residence time may be. In general, the size of the manifold and rate of recirculation 10 of: liquid should be controlled so that the liquid chargeis inthemanifold lessthan 125 seconds and preferably less than 75 seconds. The velocity of the liquid within the manifold (measured as 60 F. liquid) should becontrolled so that it is above 2 feet per second andpreferably greater than 5 feet per second.

In a typical catalytic hydrocarbon conversion process, the temperature of the contact material supplied to the reaction bed will normally fall within the range 8001200 F. For thermal conversions, the contact material will normally be supplied at considerably higher temperatures, which may range as high as 1700 F. The space velocity will normally be controlled within the. range about 1 to 10 volumes of hydrocarbon charge (as 60 F. liquid) per volume of contact material. reaction bed per hour. The ratio of contact material to hydrocarbon charge should generally be Within the range about 0.5 to 20 .parts of contact material per part of charge by weight.

While this invention has been illustrated in connection with a system which supplies hydrocarbon charge to a charge manifold substantially entirely in the liquid phase, this invention, in its broader scope, is equally applicable to systems wherein the hydrocarbon charge is supplied to the manifold as a stream of mixed vapor and liquid.

As a typical example of the operation of this invention, a petroleum charge stock having the following properties will be considered.

Source:

Kansas Mixed Gas Oils Gravity:

28.2 API Boiling range:

533 F. 5% overhead 700 F. 50% overhead 900 F. overhead This charge stock, .free from tar and asphaltic material, might be supplied to a phase separator like that of Figure 5 at a temperature of about 800 F. and at a rate of 17,000 barrels per day. The separator would be operated at about 17 pounds per square inch gauge and vapor would pass overhead at a rate of 14,000 barrels per day and at a-temperature of about 785 F. and be supplied to a reactor with internal construction similar to that of Figure 2. A synthetic silica-alumina catalyst would be passed to the reactor at about 1030 F. and then through the reactor at a rate of about 400 tons per hour. The liquid bottoms in the separator would be at a temperature of about 770 F. and 6,000 barrels per day of the bottoms would be removed and cooled to a temperature of about 500 F. andthen passed to the manifold. Liquid would be sprayed from the manifold at a rate of about 3,000 barrels per day, while 3,000 barrels per day would be recycled to the phase separator. This latter recycle liquid would be at a temperature of about 510 F. when removed from the manifold. Where a 3-inch diameter pipe is used as a manifold, the residence time of the oil in the ring might be about 4 seconds.

In another mode of operation of the above system, the temperature in the manifold could be controlled suitably low by controlling the charge temperature to the phase separator; In this case, 15,000 barrels per day of the charge might be supplied to the phase separator at about 720 F. to maintain the phase separator overhead at about 700 F. The separator bottoms might be at about 680 F, in this case and the recycle oil from the manifold about 700 F. The rate of vapor supply to the reactor Would be about 9,400 barrels per day and the rate of liquid supply about 5,600 barrels per day. The recycle oil wouldamount to 1,700 barrels per day.

Another process to which this invention is applicable is the high temperature thermal conversion of a petroleum residual stock to a suitable fuel gas. The inert material could be. coke particles having an average diameter of 0.25 inch and be circulated at 70 tons per hour. The coke particles might exist in the reaction zone at about 11 1600 F. The liquid charge might be supplied to the ring manifold at 250 F. and at a rate of 4,000 barrels per day. Of this amount, 1,000 barrels per day would be charged to the coke bed while 3,000 barrels per day would be recycled.

This invention should be understood to cover all changes and modifications of the examples of the invention herein chosen for purpose; of disclosure which do not constitute departures from the spirit and scope of the invention.

I claim:

1. In a hydrocarbon conversion process wherein a hydrocarbon charge, at least partially in the liquid phase, is converted at elevated temperatures in the presence of a hot solid contact material bed within a confined reaction zone, the method for continuously supplying the liquid hydrocarbon charge to the reaction zone, which comprises: maintaining a confined liquid plenum space within the hot reaction zone, supplying liquid hydrocarbon charge to one side of said plenum space, passing a portion of the liquid charge so supplied from the plenum space into the contact material bed, removing a second portion of the liquid charge from the opposite side of Y the plenum space and extracting heat therefrom, and returning said last-named portion of liquid charge to the plenum space after cooling together with additional liquid charge, the amount of heat extracted from said last-named portion of liquid charge being sufficient to maintain the liquid in the plenum space below the temperature at which carbonaceous material would form from the liquid in the plenum space.

2. In a continuous hydrocarbon conversion process wherein a hydrocarbon charge, at least partially in the liquid phase, is converted in the presence of a bed of solid contact material existing at a temperature above the temperature at which the liquid charge undergoes thermal conversion, which comprises: maintaining a confined liquid plenum space embedded within said contact material bed, supplying liquid hydrocarbon charge to one side of said plenum space, passing a portion of said liquid charge into said bed as a plurality of streams, removing the remaining portion of the liquid charge from the opposite side of the plenum space and returning said last-named portion to the plenum space after cooling together with additional liquid charge, the amount of heat extracted from said last-named portion of charge being sufiicient to maintain the liquid in the plenum space below the temperature at which substantial amounts of carbonaceous material would form from the liquid in the plenum space due to the thermal conversion thereof at the particular residence time of liquid in the plenum space involved.

3. A process for continuously supplying liquid hydrocarbon charge to a reaction bed of hot solid contact material maintained within a confined reaction zone at a temperature above the temperature at which the hydrocarbon charge undergoes thermal conversion with resultant deposition of coke, which comprises: passing hydrocarbon charge to a phase separator and separating the charge therein into a liquid hydrocarbon charge fraction and a vapor hydrocarbon charge fraction, passing the liquid charge fraction into one side of a liquid manifold embedded within the reaction bed of contact material, injecting a portion of the liquid charge fraction from the manifold into the reaction bed, removing the remaining portion of the liquid charge fraction from the opposite side of the manifold and returning said remaining portion to the phase separator, and controlling the temperature of the liquid charge within the manifold below the temperature at which substantial thermal conversion occurs by controlling the temperature of supply of hydrocarbon charge to the phase separator and the residence time of the liquid in the manifold.

4. In a process for the continuous conversion of fluid hydrocarbons, partially in the liquid phase, in the presence of a reaction bed of solid contact material maintained within a confined reaction zone at'a temperature above the temperature at which substantial thermal conversion of the liquid charge occurs, the process for supplying the liquid portion of the hydrocarbon charge to the reaction bed, which comprises: passing a hydrocarbon charge initially to a phase separator and separating the charge therein into a liquid fraction and a vapor fraction, passing the vapor fraction from the phase separator into the confined reaction zone and into the reaction bed therein, passing the liquid fraction from the phase separator into one side of an annular-shaped liquid manifold lying on a substantially horizontal plane and embedded in the reaction bed, passing a portion of the liquid so supplied from the manifold through a plurality of spaced-apart passages into the reaction bed, removing the remainder of the liquid fraction from the opposite side of the manifold and returning it to the phase separator, and maintaining the temperature of the liquid within the manifold below the temperature at which there is substantial formation of coke from the liquid therein by controlling the residence time of the liquid within the manifold and the inlet temperature of hydrocarbon charge to the phase separator.

5. In a catalytic conversion process wherein high boiling hydrocarbons are converted to lower boiling products by passage through a downwardly gravitating, substantially compact reaction bed of granular catalyst maintained at a temperature substantially above 800 F., the method for continuously supplying a liquid portion of the hydrocarbon charge to the reaction bed, which comprises: passing a liquid hydrocarbon charge into a ringshaped manifold embeded within the reaction bed of catalyst maintained at a temperature substantially above 800 F., spraying a portion of the liquid charge from the manifold into the bed through restricted passages, passing another portion of the liquid through the manifold and out the opposite end thereof, extracting heat from said last-named portion and recirculating it with additional liquid charge to the manifold, the rate of recirculation and of heat extraction being such as to maintain the temperature of liquid in the manifold below about 700 F., whereby overheating of the charge and rapid coke formation in the injection passages are avoidedv 6. In a catalytic conversion process wherein high boiling hydrocarbons are converted to lower boiling products by passage through a downwardly gravitating, substantially compact reaction bed of granular catalyst maintained at a temperature substantially above 800 F., the method for continuously supplying hydrocarbon charge to the reaction bed, which comprises: passing the high boiling hydrocarbon charge to a confined phase separation zone maintained at a temperature within the range about 700 F. to 850 F., whereby a portion of the charge vaporizes, passing said vaporized portion to the reaction zone, passing the portion of the charge remaining as liquid from the separation zone into a liquid manifold maintained embedded in said reaction bed, spraying part of the liquid from said manifold into the reaction bed, returning the remainder of the liquid from the manifold to the separation zone, extracting heat from said liquid stream after it leaves the separation zone but before it reaches the manifold, and controlling the residence time of the liquid in the manifold and the amount of heat extraction from the liquid stream in conjunction with each other to maintain the temperature of the liquid in the manifold below about 650 F.

7. In a catalytic conversion process wherein high boiling hydrocarbons are converted to lower boiling products by passage through a downwardly gravitating, substantially compact reaction bed of granular catalyst maintained at a temperature substantially above 800 F., the method for continuously supplying hydrocarbon charge to the reaction bed, which comprises: passing a high boiling charge containing asphaltic material to a phase separation zone and separating the charge therein into a vapor fraction free of asphaltic material and a liquid fraction containing asphaltic material, passing the vapor fraction from the phase separator into the reaction bed to be converted therein, passing the liquid fraction into a vacuum separation zone and vaporizing hydrocarbons from asphaltic material therein, condensing and cooling hydrocarbons vaporized in the vacuum separation zone and passing the liquid so formed to a confined surge zone, passing liquid hydrocarbons from the surge zone into a liquid manifold embedded Within the reaction bed, spraying a portion of the liquid supplied to the manifold into the reaction bed from the manifold, returning the remainder of the liquid from the manifold to the surge zone, and controlling the residence time of liquid within the manifold and the temperature at which liquid is supplied to the surge zone so as to maintain the temperature of the liquid in the manifold below about 650 F. and thereby avoid coke formation in the manifold.

8. In an apparatus for the conversion of hydrocarbons at elevated temperatures in the presence of hot contact material maintained within an enclosed reaction chamber, an improved apparatus for supplying liquid to said chamber and the bed therein, which comprises in combination: maintaining an enclosed liquid plenum chamber within said reaction chamber, means for supplying liquid hydrocarbon charge to one side of said plenum chamber, members defining a plurality of passageways for liquid flow from said plenum chamber into said reaction chamber, means for removing liquid charge from the opposite side of said plenum chamber, members defining a passageway connecting said liquid plenum chamber Withdrawal means with said liquid plenum chamber inlet means, and means for extracting heat situated along said passageway of sufiicient capacity to cool liquid recycled through said passageway to a temperature sufiicient to maintain said plenum chamber at a temperature below the temperature at which coke is rapidly formed in the plenum chamber.

9. In an apparatus for the conversion of hydrocarbons, at least partially in the liquid phase, at elevated temperatures in the presence of solid contact material maintained within an enclosed reaction chamber as a reaction bed at a temperature substantially in excess of the temperature at which coke is rapidly formed from the liquid hydrocarbons, an improved apparatus for supplying liquid hydrocarbons to said reaction chamber, which comprises in combination: an enclosed liquid manifold maintained within said reaction chamber, members defining a passageway for charging liquid to one side of said manifold, a plurality of spaced-apart passageways connecting said manifold and said reaction chamber, whereby a portion of the liquid charged to the manifold will pass into the reaction chamber, members defining a recycle passageway extending from the opposite side of said manifold and connecting into said charge passageway whereby a portion of the liquid charge to the manifold will be recycled, and means for extracting sufiicient heat from said recycle liquid to maintain the liquid temperature within said manifold below the temperature of rapid coke formation at the particular residence time of liquid in the manifold.

10. In an apparatus for the conversion of fluid hydrocarbons at elevated temperatures in the presence of a reaction bed of solid contact material maintained within an enclosed reaction chamber at a temperature substantially in excess of the temperature at which coke is rapidly formed from the hydrocarbon charge, an improved apparatus for supplying the hydrocarbon charge to said reaction chamber, which comprises in combination: an enclosed phase separation chamber, means for supplying the fluid hydrocarbon charge heated to a temperature sufficient to vaporize a substantial portion thereof to said phase separation chamber, members defining a passage Way for vapor flow from said phase separation chamber into said reaction chamber, an annular-shaped liquid manifold situated within said reaction chamber and having a plurality of passageways extending through the walls thereof into the reaction chamber, members defining a passageway for liquid flow from the lower section of said phase separation chamber into one side of said manifold, members defining a passageway for liquid flow extending from the opposite side of said manifold back to said phase separation chamber, and means for cooling the liquid hydrocarbons as they pass through said passageway from said phase separation chamber to said manifold .to a temperature sufiiciently low to prevent rapid coke formation in said manifold at the particular liquid residence time used.

11. The apparatus of claim 10 further limited to said annular-shaped manifold with passageways extending therefrom into the reaction chamber being a ring-shaped pipe with orifices through its underside.

l2. in an apparatus for the conversion of high boiling fluid hydrocarbons containing asphaltic material at elevated temperatures in the presence of a moving mass of granular contact material maintained within an enclosed reaction chamber at a temperature substantially in excess of the temperature at which coke is rapidly formed from the hydrocarbon charge, the improved apparatus for supplying the hydrocarbon charge to the reaction chamber, which comprises in combination: a phase separation chamber, means for supplying hydrocarbon charge heated to a temperature sufficient to vaporize substantial portions thereof Without excessive coke formation to said phase separation chamber, members defining a passageway for the flow of vapor from the upper section of said phase separation chamber, a vacuum separation chamber and means for maintaining a reduced pressure therein, members defining a passageway for the flow of liquid hydrocarbons from the lower section of said phase separation chamber into said vacuum separation chamber, a surge tank, members defining a passageway for flow of hydrocarbons from the upper section of said vacuum separation chamber into said surge tank, a cooler on said last-named passageway suitable to condense vapor dis charged from said vacuum chamber before it reaches said tank, a ring-shaped liquid manifold having a plurality of spaced-apart orifices through its underside situated within the upper section of said reaction chamber, members defining a passageway for liquid flow from the lower section of said tank into one side of said manifold and members defining a recycle passageway for liquid flow from the opposite side of said manifold back to said tank, and means for cooling said stream from said vacuum tower to said tank to a temperature sufiiciently low that the liquid in said manifold will be maintained below the temperature at which coke rapidly forms therefrom.

13. In a hydrocarbon conversion process wherein a hydrocarbon charge, at least partially in the liquid phase, is converted at elevated temperatures in the presence of a hot contact material bed maintained within a confined reaction zone, the method for continuously supplying the liquid hydrocarbon charge to the reaction zone, which comprises: maintaining a confined liquid manifold within the hot reaction zone, supplying hydrocarbon charge, at least partially in the liquid phase, to one side of said manifold, passing a portion of the charge from the manifold into the contact material bed, removing a second portion of the charge from the opposite side of the manifold, returning said second portion of charge with the fresh charge supplied to the manifold to said first-named side of said manifold, and extracting suflicient heat from said charge stream before it enters said manifold to maintain the temperature of the liquid in the manifold below the temperature at which coke is rapidly formed from said charge.

References Cited in the file of this patent UNITED STATES PATENTS 2,469,332 Evans May 3, 1949 2,482,139 Schutte Sept. 20, 1949 2,653,903 Kilpatrick Sept. 29, 1953

Claims

3. A PROCESS FOR CONTINUOUSLY SUPPLYING HYDROCARBON CHARGE TO A REATION BED OF HOT SOLID CONTACT MATERIAL MAINTAINED WITHIN A CONFINED REACTION ZONE AT A TEMPERATURE ABOVE THE TEMPERATURE AT WHICH THE HYDROCARBON CHARGE UNDERGOES THERMAL CONVERSION WITH RESULTANT DEPOSITION OF COKE, WHICH COMPRISES: PASSING HYDROCARBON CHARGE TO A PHASE SEPARATOR AND SEPARATING THE CHARGE THEREIN INTO A LIQUID HYDROCARBON CHARGE FRACTION AND A VAPOR HYDROCARBON CHARGE FRACTION, PASSING THE LIQUID CHARGE FRACTION INTO ONE SIDE OF A LIQUID MANIFOLD EMBEDDED WITHIN THE REACTION BED OF CONTACT MATERIAL, INJECTING A PORTION OF THE LIQUID CHARGE FRACTION FROM THE MANIFOLD INTO THE REACTION BED, REMOVING THE REMAINING PORTION OF THE LIQUID CHARGE FRACTION FROM THE OPPOSITE SIDE OF THE MANIFOLD AND RETURNING SAID REMAINING PORTION TO THE PHASE SEPARATOR, AND CONTROLLING THE TEMPERATURE OF THE LIQUID CHARGE WITHIN THE MANIFOLD BELOW THE TEMPERATURE AT WHICH SUBSTANTIAL THERMAL CONVERSION OCCURS BY CONTROLLING THE TEMPERATURE OF SUPPLY OF HYDROCARBON CHARGE TO THE PHASE SEPARATOR AND THE RESIDENCE TIME OF THE LIQUID IN THE MANIFOLD.