US2813757A - Solids lift disengager - Google Patents

Description

Nov. 19, 1957 R. M. SHIRK SOLIDS LIFT DISENGAGER 5 Sheets-Sheet 1 Filed Aug. 18, 1954 INVENTOR.

- ROBERT M. SHIRK TTORNEY Nov. 19, 1957 R. M. SHIRK 2,813,757

SOLIDS LIFT DISENGAGER Filed Aug. 18, 1954 3 Sheets-Sheet 2 Fig. 4

' 5 I INVENTOR. ROBERT M. SHIRK BY ATTORNEY Nov. 19, 1957 R, M, SHRK 2,813,757

SOLIDS LIFT DISENGAGER Filed Aug. 18. 1954 3 Sheets-Sheet 3 Fig. 5

INVENTOR.

ROBERT M. SHIRK soLms LIFT DISENGAGER Robert M. Shirk, Wilmington, Del., assignor to Houdry Process Corporation, Wilmington, DeL, a corporation of Delaware Application August 18, 1954, Serial No. 450,775

8 Claims. (Cl. 302-53) This invention relates generally to processes or systems in which particle-form solids or granules of contact material pass downwards through a process zone and are then pneumatically elevated into a solids-gas disengager vessel for repeated downward movement through the process zone. The present invention is particularly concerned with the construction of the disengager vessel and conduit which conducts the lifting fluid and granular material into the vessel.

While such systems have a wide range of useful applications, they have been found particularly well adapted for use in catalytic hydrocarbon conversion processes; and, the features of the present invention will be described hereinafter with specific reference to such processes. A typical system to which the present invention may be applied is disclosed in an article entitled Houdriflow: New Design in Catalytic Cracking, appearing in the Oil and Gas Journal, page 78, January 13, 1949. As noted therein, the use of a gas for lifting pelleted or head catalyst from the bottom to the top of the unit permits better operating control with considerably increased efiiciency (including reductions in the costs of installation and maintenance). For most efficient operation, it is desirable to employ flue gas, as from the process zone, for elevating the granular material. However, the relatively high catalyst temperatures, usually over 1000 F. in hydrocarbon conversion processes, cause considerable thermal expansion of the lift conduit, which may be 200 or more feet high. Heretofore, it has been necessary to provide the disengaging chamber with a packed joint slidably receiving the lift conduit where it enters the chamber, permitting expansile and contractile movement of the conduit relative to the chamber. This joint, of course, required maintenance and was, by its location, relatively inaccessible and difficult to service.

As separation or disengagement of the lift gas from the particle-form catalyst is accomplished by complete gravitational deceleration of the latter within the chamber, and free, catalyst fall to the bottom or onto the surface of a layer of catalyst providing a surge bed in the lower region of the chamber, it is essential for unimpeded lift operation that the upper end of the lift conduit be disposed above the catalyst level in the disengaging chamber. Thus, the upper portion of the lift conduit must extend a substantial vertical distance into the disengaging chamber and be of such strength and size to resist pressure exerted by the moving bed of disengaged catalyst without obstructing flow of the bed. It is to be understood that the upper portion of the lift conduit while usually vertical may deviate as much as several degrees from the vertical depending on design considerations. In the prior art, the upper end portion of the lift conduit was either (1) supported only where it entered into the disengaging chamber, or (2) supported both at its point of entry into the chamber and at some second point interiorly of the chamber, which required two packed joints and their concomitant disadvantages.

States Patent 2,813,757 P atented Nov. 19, 1957 ice In accordance with the present invention, a disengager construction is provided in which the lift conduit extends upwards into the disengager vessel through and beyond the level of the surge bed of disengaged catalyst on the bottom thereof, is not subject to pressure from the disengaged catalyst, is firmly supported by novel means which permits thermal expansion and contraction of the entire lift conduit and does not obstruct movement of the catalyst bed. By the novel arrangement and construction of the present invention, the above noted advantageous features are accomplished without the use of packed joints, and by a construction which requires little or no maintenance over extremely long periods of operating time. Further, the lift conduit supporting structure is relatively inexpensive to manufacture, and small and compact in use, so as to occupy a minimum of space within the disengager vessel.

The present invention also contemplates improved baffie or tray construction and arrangement within the disengager vessel above the surge bed, serving to interrupt the free falling movement of the granular material and pass the latter stagewise, with a minimum of attrition, to the surge bed, and cooperating with the lift conduit to support the latter and permit thermal expansion and contraction thereof. By the proposed construction, a plurality of vertically spaced catalyst collecting trays may be provided, all permitting the upward movement therethrough of one or more lift paths, and cooperating to pass the falling catalyst between trays while maintaining a covering bed of catalyst on each tray to soften the fall of catalyst from the next upper tray and reduce attrition of the catalyst.

Other objects of the present invention will become apparent upon reading the following specification and referring to the accompanying drawings, which form a material part of this disclosure.

The invention accordingly consists in the features of construction, combinations of elements, and arrangements of parts, which will be exemplified in the construction hereinafter described and of which the scope will be indicated by the appended claims.

In the drawings:

Figure 1 is a sectional, elevational view showing a disengager constructed in accordance with the present invention;

Fig. 2 is a horizontal sectional view taken substantially along the line 2-2 of Fig. 1 and showing an upper bafile or catalyst collecting tray of the disengager;

Fig. 3 is a horizontal sectional view taken substantially along the line 33 of Fig. 1, and showing a lower bafile or collecting tray in its operative relation with the lift conduit;

Pig. 4 is a fragmentary, enlarged view showing the upper end portion of the lift conduit construction in greater detail, and the adjacent portion of the lower bafile tray; and

Fig. 5 is a horizontal sectional view taken substantially along the line 5-5 of Fig. 4.

Referring now more particularly to the drawings, and specifically to Fig. 1 thereof, the embodiment of the invention illustrated therein comprises a generally vertically disposed disengager vessel 10, which is supported in elevated position, and a plurality of upright lift conduits or pipes 11, only one being shown in Fig. 1, each having its upper end portion extending into the disengager vessel spacedly through the bottom of the latter.

The disengager vessel is mounted at an elevation completely above the processing zone, frequently at a height of more than 200 feet, so as to permit gravity feed of granular material from the disengager to the processing zone. In order toconserve drawing space, the lower 3 portions of the disengager supporting structure 13 and the lift conduits 11 have been broken away. The disen gager vessel illustrated in the drawings is vertically elongated, and circular in cross section, including a cylindrical side wall 14, an upwardly dished top wall 15 closing the upper end of the side Wall, and a downwardly dished bottom wall 16, which closes the lower end of the vessel. A lift gas outlet duct or stack 17 may be provided in the vessel top wall 16; and, a seal leg or conduit 18 may be connected to the bottom wall 16 for conducting granular material out of the lower vessel region. Of course, the disengager vessel may be provided with manholes or access openings, as desired, and additional granular material outlet means communicating with an elutriator and catalyst storage chamber. Further, a downwardly facing, concave target plate or bafiie 19 may be fixed, as by brackets 20, in spaced relation below the vessel top wall 15 directly under the stack 17.

Fixedly secured internally of the disengager vessel 10, spaced from the upper and lower ends of the latter, are transversely disposed, vertically spaced catalyst collecting trays or bafides 22 and 23. While two collecting trays or baffles have been illustrated in the drawings, it is of course appreciated that the number may be more or less, depending upon the catalyst flow requirements of the particular installation. Both of the collecting trays are illustrated as being downwardly depressed or dished, and of generally circular configuration conforming to the interior of the vessel side wall 14. More particularly, the lower catalyst collecting bafde 23 is formed of a generally circular, upwardly concave plate having an upwardly extending peripheral flange 24 secured to the interior of the vessel wall 14, as by welding or other suitable means. The bafile 23 is provided with one or more symmetrically arranged, relatively large through openings 25, illustrated as three in number and arranged eccentrically of the baffle, angularly spaced 120 apart. Extending about the periphery of each aperture 25 is a vertically disposed, tubular wall or coaming 26, each of which is fixedly secured to the bafiie 23, as by welding, and has its upper and lower ends spaced, respectively, above and below the baffie.

A relatively small aperture or opening 28 is formed centrally of the bafiie 23, and a tubular, open ended conduit or downcomer 29 is secured in the central aperture, having its upper end spaced above the upper baflie surface and its lower end spaced considerably below the undersurface of the baffle. Arranged in groups adjacent to the peripheral flange 24 are a plurality of relatively small, circumferentially spaced apertures or openings 30, each group being disposed intermediate an adjaceut pair of the relatively large apertures 25. An open ended, tubular conduit or downcomer 31 is fixed in each of the circumferentially spaced openings 36), with its upper end spaced a short distance above the upper surface of the baffle 23 and its lower end spaced a substantially greater distance below the undersurface of the baffle. Brackets 32 may be provided on the interior of the peripheral side Wall 14 for more rigidly holding the downcomers 31 in position.

The upper catalyst collecting baffle or tray 22 is formed of a generally circular, upwardly concave plate, conforming to the interior of the disengager vessel 10 and having a discontinuous, peripherally extending securing flange 34, which is welded or otherwise fixed to the interior surface of the disengager side wall 14. While plates or trays 22 and 23 have been described as concave in form, they may have other suitable form including that of being fiat. A plurality of relatively large through openings 35, shown for purposes of illustration as three in number, are formed in. the upper baffle 22 and each arranged in vertical alignment with one of the openings 25 of the lower bafiie 23. However, the openings 35 are considerably larger than the openings 25, and extend between the ring 48 and lift pipe 45.

radially outwards through the peripheral edge of the baffle 22, as best seen in Fig. 2. Extending along and fixedly secured to the bounding edge of each opening 35 is a vertical wall or coaming 36.

A relatively small, central opening 37 is provided in the upper bafile 22; and, an open ended tubular pipe or downcomer 38 is fixedly secured in the opening 37 with its upper end disposed slightly above the adjacent upper surface portion of the bafile 22 and its lower end depending a substantial distance below the bafiie. Thus, the aperture 37 and its downcomer 38 in the upper bafile are in substantial alignment with the aperture 28 and its downcomer 29 in the lower bafiie. However, in order to prevent the catalyst moving through downcomer 38 from falling directly through downcomer 29 a deflecting plate 39 is interposed between the lower end of downcomer 38 and the upper end of downcomer 29.

Adjacent to the periphery of the upper bafiie 22, in the space between each adjacent pair of relatively large apertures 35, are formed a group of circumferentially spaced, relatively small apertures 40 each provided with an open ended tubular conduit or pipe 41 extending therethrough. That is, each of the pipes 41 has its upper and lower ends, respectively, spaced above and below the adjacent bafiie portions, and is fixedly secured to the bounding edge of the associated aperture. Radially inwards from the apertures 40, the bafiie 22 is provided with additional, relatively small apertures 42, each having an open ended tubular member 43 fixed therein with its upper and lower ends spaced, respectively, above and below the baffle portions adjacent thereto. It will be noted that the apertures 40 of the upper baffle are angularly spaced relative to the apertures 30 of the lower baffle, so that the pipes. 41 are laterally ofiset with respect to the pipes 31.

While the disengager construction thus far described is adapted to accommodate a plurality of lift conduits, namely three in number, it is appreciated that the num ber of lift conduits may be greater or less, as desired. The lift conduits are preferably identical in construction so that it will suffice to describe only one, best seen in Fig. 1. Each of the lift conduits 11 includes a pipe 45, which may be increasing in diameter toward its upper end 46. The lower end or bottom. 16 of the vessel 10 is formed with a through opening 47 in which is fixedly secured a ring or collar 48. The pipe 45 extends upwards from its external supporting structure (not shown) through the opening 47 in spaced relation with respect to the ring 48, andv terminates adjacent to the lower bafiie 23 in alignment with one of the bafiie openings 25. Of course, each of the lift pipes 45 are disposed in alignment with a difierent one of the baffle openings 25.

An outer pipe or sleeve 50 is. arranged within the chamber 10: spacedly surrounding the conduit 45, and has its lower end 51 fixedly secured to the disengager bottom wall 16 as by welding, or other suitable means, surrounding, the ring 48. and aperture 47. Hence, any granular material resting on the bottom wall of the disengager will be prevented from passing downwards through the space The upper end 52 of the sleeve or shell 50 extends to a point adjacent to but spaced below the upper conduit end 46, and an expansion or slip joint, generally designated 54, is connected between the upper ends of the lift pipe and sleeve.

As best seen in Fig. 4, the expansion joint 54 includes a lower cylindrical member or annulus 55 spaced circumposed about the lift pipe 45 and having its lower end fixedly secured, asby welding, to the upper end 52 of the sleeve 50. That is, the lower end of the annulus S5 is welded about the internal circumference of the band 56, which is in turn welded interiorly to the upper end of the sleeve 50. An upper cylindrical member or annulus 57 is arranged in alignment with and spaced above the lower annulus 55, and has its upper end peripherally secured to the lift conduit 45 adjacent to and spaced below the upper end of the latter. More particularly, a laterally outwardly extending, peripheral flange 58 is secured about the lift pipe 45, as by welding, at a point adjacent to and spaced below the upper end 46 of the latter, and the upper annulus 57 has its upper end peripherally secured to the undersurface of the flange spaced inwards from the outer edge of the latter. A plurality of vertically spaced, extensile and retractile tubular sections or bellows 60, three being illustrated in the drawings, are circumposed about the lift pipe 45 between the upper and lower annuli 57 and 55, the upper and lower bellows sections, respectively, having their upper and lower ends peripherally secured, by any suitable means, to the upper and lower annuli. Intermediate cylindrical members or annuli 61 are spacedly circumposed about the lift conduit 45 and each peripherally secured between an adjacent pair of the bellows sections 60. It will now be understood that the bellows sections 60 combine with the annuli 55, 57 and 61 to provide an expansile and contractile sheath or sleeve surrounding the upper end portion of the lift pipe 45 and peripherally secured to the lift pipe and shell 50.

Depending from the peripheral edge of the annular flange 58, and spacedly surrounding the expansile sheath construction is a generally cylindrical housing or skirt 62. The housing 62 has its upper end peripherally secured to the flange 58, as by fasteners 63, its lower end being open and depending to a point below the upper end of the shell 50, when the lift pipe 45 is in its cool, contracted condition. An internal guard or shield 65, of generally cylindrical shape, is spacedly circumposed about the expansile sheath construction, interiorly of the housing 62, having its lower end fixed to the upper shell end 52, and its upper end disposed above the upper bellows sections 60. That is, the lower end of the guard 65 is secured by fasteners 66 to the brackets 67, which are in turn fixed exteriorly of the upper sleeve end 52. It will be observed that the inside diameter of the coaming 26 is greater than the outside diameters of the flange 58 and housing 62, so that unobstructed upward movement of the latter into the coaming may take place upon expansion of the lift conduit.

In order to guide expansile and contractile movement of the lift conduit, and afford lateral support to the lift conduit in all positions of its expansile and contractile movement, a plurality of generally triangularly shaped shoes 70, four being shown for purposes of illustration, are arranged to extend radially outwards from the lift pipe 45 adjacent to the upper end thereof, and fixedly secured to the lift pipe and the upper surface of the flange 58. Thus, the radially outward edges of the shoes 70 are slidably engageable with the internal surface of the coaming 26 to restrain lateral lift conduit deflection and guide expansile and contractile movement of the lift conduit.

In operation, the relatively hot flue gases from the process zone serve to impel the granular contact material upwards through the relatively long lift pipe 45 and heat the latter to cause considerable thermal expansion thereof. While expansion of the lift pipe is largely in the longitudinal direction, there will be slight thermal expansion circumferentially. However, by the construction of the present invention, binding or restraint of lift pipe expansion in all directions is eliminated. More particularly, the lift pipe portion disposed spacedly within the bottom wall ring 48 and shell 50 is freely expansible therein, both longitudinally and circumferentially; and, total thermal expansion of the lift pipe 45 is permitted by extension of the bellows sections 60. As seen in dashed outline in Figs. 1 and 4, showing the thermally expanded position of the lift pipe 45, the bellows sections 60 will open or expand to permit upward movement of the upper lift pipe end 46 into the coaming 26 while keeping closed the space between the lift pipe and outer shell 50. As noted hereinbefore, the radially extending shoes 70 are engageable with the coaming 26 to guide and support the upper end of the lift pipe, and are of the proper size to permit the relatively slight circumferential lift pipe expansion without binding in the coaming.

As the outer housing or skirt 62 is fixed to the upper end of the lift pipe 45, and the inner guard or shield 65 is fixed to the shell or sleeve 50, it is apparent that the skirt will move upwards with the lift pipe to cover and protect the upwardly moving bellows sections and expose the inner shield, which serves to protect the lower bellows sections. Hence, the telescopic action of the housing 62 and shield 65 effects protective enclosure of the bellows sections 60 in all positions of bellows expansion.

Upon emerging from the upper lift conduit end 46, the granular material and lift gas will pass upwardly through the relatively large opening 35 associated with the particular lift conduit, and enter into the relatively large upper disengager region above the upper baffle 22, ,which is preferably of such a height as to permit substantially complete deceleration of the granular material before impingement against the target plate or bafile 19. The lift gas will then be exhausted through the outlet 17, and the granular material permitted to fall freely to the upper bafile 22.

A moving bed of granular material is maintained on the entire surface of the upper collecting tray 22, the depth and surface contour of the bed being determined by the arrangement of apertures and height of the tubular members disposed in the apertures. Thus, as seen in Fig. 1, the relatively great height of the tubular members 41 and 43 insures the maintenance of a bed of substantial depth, while the relatively small height of the tubular member 38 above the bafiie 22 permits the bed depth to decrease toward the center of the collector tray. Of course, the coaming 36 surrounding the apertures 35 are of suflicient height to prevent overflow of granular material from the bed maintained on the upper baflle into the path of the upwardly moving flue gas.

As the upper baffle apertures 40 and 42 are arranged laterally offset from, and not directly over any of the apertures 30 in the lower baffle 23, it will be understood that the granular material bed contour on the lower baflle will be determined in part by the arrangement of the apertures in the upper baffle. Any granular material passing downwards through the upper baflie apertures 40 and 42 will have its free fall interrupted and cushioned by engagement with the bed maintained on the lower baffle, so as to substantially reduce attrition of the granular particles.

While the bed contour on the lower baffle 23 depends in part on the distribution of granular material falling from the upper bafiie 22, it is also determined in part by the height of the downcomers 29 and 31 above the lower bafile, as best seen in Fig. 1. That is, the bed depth on the lower baffle 23 is maintained relatively low both centrally and about its periphery by the downcomers 29 and 31; and, the coamings or walls 26 are of sutficient height to prevent overflow of granular material from the lower bed baffle into the path of the upwardly moving lift gas.

The granular particles from the lower balfle plate 23 will flow downwards through the downcomers 29 and 31 into a storage zone in the lower region of the disengager, so that the disengaged granular material rests on the bottom wall 16 in the form of a compact bed and moves downwardly therefrom through the conduit 18 to the processing zone. The, maximum upper level of the storage zone bed is determined by the disposition of the lower ends of the downcomers 29 and 31, which are arranged to maintain the bed surface below and out of contact with the expansion joints 54. Since the lower region of vessel 10 contains the surge for the circulatory system, the surface of the bed at the bottom of vessel 10 will rise and fall, but is always below the lower ends of downcomers 29 and 31. Thus, there is a free fall of catalyst from these downcomers. Hence, the disengaged granular material falls freely stagcwise 7 downward between the catalyst collecting trays, and from the lowermost collecting tray to the compact bed of the storage zone.

It is now seen that the shell 56 and bellows type sheath construction serve to completely enclose the portions of the lift pipes 45 disposed within the disengager vessel, the shell 50 further serving to prevent pressure from the storage bed being applied against the lift conduit, and the extensile sheath permitting free thermal expansion and contraction of the lift pipe while excluding granular material from the space between the shell and pipe. Further, the bellows sections 60 are completely protected from contact with particles of the granular material by the telescopically arranged housing 62 and shield 65, so that good bellows operating conditions are assured.

From the foregoing, it is seen that the present invention provides a solids-gas disengager construction which fully accomplishes its intended objects, and which is well adapted to meet practical conditions of manufacture, installation and operation.

Obviously many modifications and variations of the invention as hereinbefore set forth may be made without departing from the spirit and scope thereof, and therefore only such limitations should be imposed as are indicated in the appended claims,

What is claimed is:

i. In a pneumatic lift for elevating granular material by gaseous fluid, the combination comprising a disengaging chamber supported in elevated position, an upright lift conduit having its upper end extending into said disengaging chamber spacedly through the bottom of the latter for discharging granular material and lift gas into said chamber, the region in said chamber above said lift conduit providing a zone for disengaging the granular material from the lift gas by complete gravitational deceleration and free fall, a sleeve disposed within said chamber spacedly surrounding said lift conduit and having its lower end secured to the bottom of said chamber and its upper end disposed below the up per end of said lift conduit, said sleeve thus serving to prevent the passage of granular material through the space betweeen said lift conduit and the bottom of said chamber, an extensile and contractile sheath surrounding said lift conduit above said sleeve and peripherally secured to said lift conduit and sleeve, to permit thermal expansion and contraction of said lift conduit and exclude granular material from the space between said sleeve and lift conduit, a transversely disposed bafiie secured in said chamber for interrupting the free fall of said granular material, and relatively slidable guide means on said bafile and lift conduit for laterally supporting the latter in any position of its thermal expansion and contraction.

2. The combination according to claim 1, wherein said sheath comprises a bellows construction adapted to exclude relatively fine granular material from the space between said sleeve and lift conduit.

3. The combination according to claim 1, said guide means comprising a wall surrounding said lift conduit and fixed to said bafile for retaining disengaged granular material on said batlle out of the path of said lift gas, and a plurality of circumferentially spaced shoes carried by said lift conduit and in slidable engagement with said wall to laterally support said lift conduit and permit thermal expansion and contraction of the latter.

4. The combination according to claim 1, in combination with a skirt spacedly surrounding said sheath and fixedly secured to a peripheral portion of said lift conduit above said sheath to protect the latter from contact with granular material.

5. The combination according to claim 4, in combination with a guard arranged surrounding said sheath interiorly of said skirt and fixed to said sleeve, said guard being exposed upon expansion of said lift conduit and consequent upward movement of said skirt to protect the lower portion of said sheath from contact with granular material.

6. In a pneumatic lift for elevating granular material by gaseous fluid, the combination comprising a disengaging chamber supported in elevated position, an upright lift conduit having its upper end extending into said disengaging chamber spacedly through the bottom of the latter for discharging granular material and lift gas into said chamber, the region in said chamber above said lift conduit providing a zone for disengaging the granular material from the lift gas by complete gravitational deceleration and free fall, and the space below the upper end of said lift conduit providing a storage zone containing a compact bed of disengaged granular material, a sleeve disposed within said chamber spacedly surrounding said lift conduit and having its lower end secured to the bottom of said chamber and its upper end disposed above said storage zone and below the upper end of said lift conduit, said sleeve thus serving to shield said lift conduit from the pressure of granular material in said bed and prevent the passage of granular material from said bed through the space between said lift conduit and the bottom of said chamber, an extensileand contractile sheath surrounding said lift conduit above said sleeve peripherally secured to said lift conduit and sleeve, to permit thermal expansion and contraction of said lift conduit and exclude granular material from the space between said sleeve and lift conduit, a plurality of transversely disposed bafiles secured in vertically spaced relation within said chamber for interrupting the free fall of said granular material, each of said baffles being formed with openings to permit the upward passage of said lift gas and granular material and the downward movement of said disengaged granular material, and relatively slidable guide means on said lift conduit and one of said bafiles for laterally supporting said lift conduit in any position of its thermal expansible and contractile movement.

7. The combination according to claim 6, said guide means comprising a coaming spacedly surrounding said lift conduit and fixedly secured about an opening of one of said baffles for retaining disengaged granular material on said one bafile out of the path of said lift conduit, and a plurality of circumferentially spaced shoes carried by said lift conduit and in slidable engagement with said coaming to laterally support said lift conduit and permit thermal expansion and contraction of the latter.

8. The combination according to claim 6, wherein at least one opening of each baffle is in vertical alignment with at least one opening of each remaining baffle to permit upward passage through said one baffle opening of said lift gas and granular material, and other openings of each baffie are laterally offset with respect to other openings of each adjacent bafiie to' permit falling movement of said disengaged granular material stagewise through the other openings of each baffle to the-next lower bafile.

References Citedin the file of this patent UNITED STATES PATENTS 1,992,612 Hall Feb. 26, 1935 2,014,355 Hussman Sept. 10, 1935 2,506,293 Copeland May 2, 1950 2,541,077 Lelfer Feb. 13, 1951 2,547,746 Cook Apr. 3, 1951 FOREIGN PATENTS 884,804 France Aug. 27, 1943

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