Idea Transcript
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J. s. CLARKE
2,690,962
VESSEL FOR CONTACTING GASEOUS FLUIDS AND SOLIDS
Filed Oct. 6, 1952
2 Sheets-Sheet 1
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Oct. 5, W54
J. 5. CLARKE
2,690,962
VESSEL FOR CONTACTING GASEOUS mums AND SOLIDS
Filed Oct. 6, 1952
2 Sheets-Sheet 2
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Patented Oct. 5, 1954
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PATENT ‘OFFICE 12,890,962 'vEss'EL Fort CONTACTING GASEOUS
FLUIDS AND SOLIDS James 58. Clarke, "Cranford, N. J-.-, *as'signo'r to Standard 'Oil Development Company, a corpo ration-of Delaware
Application ‘October 6, 1952,‘Serial No. 313,319
l
'5'Claims. (01. 23-288)
invention relates to an apparatus for ‘cone
‘t'ac‘t'in'g ‘?nely divided solids with gaseous ?uids and more particularly relates to a'vessel provided with a new type of grid or distributing member
for evenly distributing ‘solids and/ or gaseous ?uids
2 The new concave spherical grid is supported in position entirely from the periphery thereof wii'thout'the need of intermediate supports. The ‘concave spherical grid has a further operating advantage from the standpoint of distribution
across the area of the vessel.
in that the depth of the ?uidized solids bed is ‘greater ‘at the center which tends to reduce vapor or gas ‘?ow through the ‘center of ‘the solids bed are used the gaseous fluid ‘such as hydrocarbon and thus counteracts the usual tendency for the vapors and catalyst pass as a relatively dilute 10 ‘?ow of gas or vapor to be greater at the center suspension through ‘a line into the bottom of the of the ?uidized solids b'ed. ‘More ‘of the gas ‘or reactor below a distributing grid member which "vapor will be directed to portions of the ?uidized ‘heretofore has been a flat circular; perforated solids bed than the center and better contacting plate supported at its periphery and also-at points ‘of solids and gas or vapor will be obtained. The intermediate between the "center and the periph new grid can be used 'in any process employing ery. In certain types of construction the gas or a con?ned or circulating bed of ?uidized solids ‘vapor is admit-ted to the vessel at a point ‘di which gas is to be ‘passed up through the bed rectly below the center of the grid member. With ‘of solids. this type of construction ~the gas or vapor ?ows 'The degree of curvature of the ‘spherical grid
In ?uidized solids systems such‘ as catalytic ‘cracking units where ?uidized catalyst particles
through the grid and there is vconcentration ‘of
bed adjacent the Walls of the vessel and because
may be varied to give optimum balance between the central inlet effects of gas ‘or vapor and vsl‘ip‘pres's‘ion of central ‘?ow of gas or vapor by added depth of ?uidized ‘solids bed at the center. In ‘the ‘drawing: Fig. '1 represents a partial vertical section ‘or a vessel with the grid in position and with parts
of less resistance more gas or vapors ?ow through
broken away to ‘facilitate the disclosure;
the less dense central portion of the ?uidized bed and poor contacting between the catalyst and
Fig. 32 represents a detail showingthe peripheral support for the ‘grid ; and Fig. 3 represents a diagrammatic View ‘of part of the vessel showing ‘the relationship between the diameter of the ‘vessel, the radius of curvature or the grid ‘and the amount of dishing of the grid.
the up'?owing gas or vapor at the center of the grid member. As more gas or vapor ?ows ‘up
throughthe center of the grid member, the den ‘sity of the ?uidized bed of solids above the ‘grid "member is less than the ‘portions ‘of the ?uidized
vapors or gases isobtained.
While some improvement is obtained with a
de?ecting member below the grid, the problem of more ‘gas or vapor passing upwardly through the center of the ?uidized bed than in the an nulus adjacent the vessel wall is not overcome. The same problem is present in regenerator vessels for ?uidized catalysts using a grid mem ber. The present invention is ‘not ‘to be restricted
to catalytic cracking ‘operations because it is
,
‘ Referring now to the drawing the reference character ‘l0 designates a vertical cylindrical ves sel which may be a reactor or regenerator in a catalytic cracking system or may be a vessel useful for contacting ‘gas or vapor with ?uidized ‘solids for any desired reaction where the gas or
applicable ‘to all processes where even distribution 40 vapor passes ‘upwardly through the vessel It. of a gas or vapor is desired to a fluidized bed of Vessel It is provided with a large central cylin
vsolids.
According to the present invention in the con
drical portion H, ‘a bottom inlet l2 for gaseous
?uid ‘and a top outlet I3 for removing reaction vapors or gases or gaseous ?uid after contact tacting' a con?ned of ?uidized chamber solids wherein withthe gasgas or or vapor vapor 45 with the ?uidized bed It of solids diagrammatical How is upwardly a new type of grid member ‘is ‘1y shown by dots in the drawing and having a provided at the bottom of the ?uidized solids bed 1eve1 indicated at vl5. Bottom inlet I2 is con to promote even distribution of the ‘rising gas or nected to the bottom of the central large cylin vapor throughout the bed. The new type of ‘grid drical portion ll by an inverted fru'sto-conical is equivalent to or approximates a portion of a 50 portion Hi. Top ‘outlet I3 is connected with the top sphere disposed in the contacting vessel concave of the central large cylindrical portion H by a upward. The grid is dished out and in position frusto-conical portion i1. Alternately, members has vthe ‘appearance of a dish with the concave ‘It ‘and il may be hemispherical, elliptical, etc. face being arranged on the upper side ‘similar to 'dep'en'dingupon constructional preferences in any a dish resting in its normal position on a surface.
particular application. Conical member I6 forms
2,690,962
3 a bottom conical closure associated with open ing :2. The gaseous ?uid passing upwardly through vessel ID has a super?cial velocity of between about 1.0 and 5.0 feet per second in a cracking
or regeneration operation where the catalyst is commercial silica-alumina of about 100 to 400 mesh or ?ner with the greatest proportion of the particles being between about 0 and 150 microns to produce a dense fluidized turbulent liquid 10
4
top of the de?ector member 48. Member 48 is generally parallel to grid 18 but the conical wall of de?ector 48 is relatively ?at and would, if extended, intersect the wall of the bottom section it‘ of vessel IS. The de?ector member 48 is
spaced from the bottom wall [6 of vessel H! and above inlet l2 by a plurality of spacer or support members 54 which comprise arms or supports suitably secured to wall I6 and de?ector member
48. As the gas or vapor passes up through inlet line I2 it strikes de?ector member IE8 and passes The distributing perforated grid of the present through the annular passageway 56 formed by invention is shown at !8 as a circular or round the outer end of the conical shaped de?ector dished or concave grid provided with a multiplic ity of openings 22 to permit passage of gas or 15 member 48 and the bottom wall is of vessel I0. In cases where a con?ned bed of catalyst par vapor therethrough. The grid [8 is arranged con ticles or contact particles is maintained in a cave upward so that its central portion 24 is lower vessel, it may be necessary only at certain inter in vessel l0 than its periphery 26. Preferably vals to add make-up catalyst or to replenish used the grid is a segment of a sphere. Grid [8 may catalyst. In cases where catalyst or contact par be made of one piece in small installations or as ticles are to be regenerated or heated in a sepa two or more parts in larger installations. Ir rate vessel and then returned to the reactor, it respective of whether the grid is made of one simulating mixture or bed.
piece or two or more parts it is only necessary
is necessary in a continuous process to remove
the particles continuously and to supply regen to support the spherical segment grid at its pe riphery 265. Using large conventional ?at grids 25 erated or heated particles to the ?uidized bed.
Vessel H1 in Fig. 1 is shown as provided with an it was necessary to support the ?at grids at the inlet 58 for the introduction of fresh or regen periphery and also at other points between the erated or heated catalyst or contact particles center and the periphery. The intermediate sup to the ?uidized bed on grid I8. Where catalyst port members are objectionable as they represent considerable expense to provide and install, they 30 or contact particles are fed into vessel It) with the gas or vapor passing through inlet 12, inlet are subject to erosion and high maintenance and 58 may be used for adding make-up catalyst. when in position have an adverse effect on dis Vessel I0 is also provided with a withdrawal well tribution. 62 extending into the dense ?uidized bed but As shown in Fig. 2 grid H3 at its periphery has a ?at annular portion 28 which rests on horizontal 35 preferably below the level It thereof for with drawing solids particles from the ?uidized tur ?at portion 32 of support assembly 315. A plurality bulent bed for regeneration and/ or reheating via of assemblies 34 is provided around the vessel. line 64. Each support assembly 34 has a vertical wall 35 An annular seal plate 66 is provided beyond and an angular base portion 36 which is suitably secured, as by welding, to the inner wall of the 40 the periphery 26 of grid l8 to function as a grid seal to prevent by-passing of gas around the inverted frusto-conical bottom portion 16 of ves grid. sel III. The grid I8 is secured to the supports 34 If the de?ector member 48 were omitted it can by bolts or the like 42 each of which extends be seen that with a conventional ?at perforated through an elongated slot 1115 in the ?at annular grid plate, most of the gas or vapor from line portion 28 of grid I8 and an opening in ?at hori l2 would pass up through the center of the grid zontal portion 32 of supports 34. Since the inner because of the velocity and direction of flow of walls of the vessel may be insulated and thus the gas or vapor. Also the density of the solids will be at a lower operating temperature than mixture above the center of the grid would be the grid, the elongated slots M. permit expansion of the grid when it is heated to the temperatures ; less than in the outer portions of the ?uidized bed and this would exaggerate ?ow of gas or to be used in the reaction. In catalytic cracking vapor through the center of the solids ?uid bed. the temperature in the reactor may be about Some improvement can be obtained by using the 850-1000° F. and in the regenerator may be about de?ector member with the conventional ?at grid. 900°-1200° F. In regenerating catalyst, air or air plus spent catalyst is passed upwardly through . The de?ection of the inlet gases necessary to approach even distribution, however, results in inlet line l2. In the cracking phase of the process, excessive erosion of the de?ector and the walls vaporized hydrocarbon plus regenerated catalyst of the bottom section It of the vessel. is passed upwardly through inlet line l2. In the present invention when using a dished Instead of supporting the support assembly or round spherical segment grid [8, depth of the units on the inner wall of bottom portion I8, bed as shown by “h” at the center is greater than support assemblies of different shape, as for ex it is at the outer portion at “In.” The added ample blocks, may be secured in spaced relation depth at the center tends to suppress ?ow through in any suitable manner to the bottom portion of the center and as a result, with the inlet gases the internal wall of cylindrical portion H just
above the junction of the cylindrical portion H 65 entering the vessel below the center, the problem of obtaining even distribution of gas ?ow through and bottom portion [6. When gas or vapor is passed upwardly through inlet [2, which is shown as arranged below the center of grid 18, it is preferred to provide a de ?eeting member 15.8 in the lower portion of vessel Ill below grid l8. One form of de?ecting mem ber 48 is shown in Fig. 1 as having an inverted frusto-conical shape. Member 138 has an open ing 52 in the bottom thereof to permit return to the gas stream of solid particles collecting on 75
the bed is not as dif?cult as with a ?at grid under the same ?ow conditions. Less severe diversion of the inlet stream is required to obtain even distribution. As a result, the inlet de?ector may be of smaller dimensions and erosion of the de
?ector, of its supporting members, and of the vessel walls under the de?ector is reduced greatly below that which would occur with a ?at plate
grid with de?ector.
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In a catalytic cracking unit where the typical average regenerator is about 23 feet in internal diameter, the spherical portion of grid 18 is on a 23 foot radius for this particular design but other curvatures may be used. For this design the grid 18 has about 1400 one inch holes 22 and the grid is about 5/3 inch thick and 16 peripheral support assemblies 34 are used.
2. An apparatus according to claim 1 wherein ' a gas de?ector member is arranged below said
grid and above the inlet in said bottom closure
plate.
3. An apparatus according to claim 1 wherein
said grid is supported only at its periphery, spaced supporting means are secured to said bot
The inlet [2 is
tom closure plate adjacent the periphery of said about 34 inches in diameter. For this design the grid and means are included for securing the bottom of concave or dished grid I8 is about 2.4 10 periphery of said grid to said supporting means. feet below the ?at annular peripheral portion 26 4. An apparatus including a vertically arranged of the grid or the difference between “h” and vessel having a cylindrical center portion and a “in” is about 2.4 feet, so that there is an ap bottom inverted frusto-conical portion extending preciable difference in the depth of the center down from the bottom of said cylindrical portion of the bed of ?uidized solids and the depth of 15 and a top frusto-conical portion extending up the bed at the outer periphery of the bed. A ward from the upper portion of said cylindrical representative bed height for a ?uidized catalyst portion, a. gas inlet line communicating with the vessel of these dimensions would be about 15 feet. small lower end of said inverted conical portion, Fig. 3 shows the curvature or the amount of a gas outlet line communicating with the small dishing of the concave dished grid 22 in vessel upper end of said upper conical portion, a circular ID. The dished grid forms a portion of a sphere dished grid formed from a section of a sphere and as given in the speci?c example, the radius and arranged adjacent the lower portion of said of the sphere from which the grid is formed is cylindrical central portion of said vessel, said grid substantially the same as the diameter of the
being arranged concave upward so that the cen
vessel. In Fig. 3, D represents the diameter of 25 tral portion of the grid in said vessel is below the the vessel and the radius of curvature of the plane of the periphery of said grid a distance of grid. The right angle triangle formed in Fig. 3 the order of shows the hyptoenuse as D, the horizontal side as 2-1/3" D 30 2 where D is substantially equal to the radius of and the vertical side as curvature of said grid and also substantially equal to the diameter of said vessel. 5. An apparatus including a, vertical disposed 35 vessel having a cylindrical body portion and a Hence the distance from the bottom of the grid bottom closure plate provided with an inlet for to the plane of the periphery, designated X equals gaseous ?uids, a top outlet for gaseous ?uid from
D< 2 )
BTW
egg
and this in turn equals
said vessel, a circular concave gas distribution grid formed from a section of a sphere and sup
40 ported at its periphery at the upper portion of
said bottom closure plate, said grid being ar ranged in said vessel so that the central portion of the grid is below the plane of the periphery of said grid a distance of the order of
D 1 —E which in turn equals
45
was
D(—2'“§)
2 What is claimed is: where D is substantially equal to the radius of 1. An apparatus including a, vertically disposed 50 curvature of said grid and also substantially equal vessel having a cylindrical body portion and a to the diameter of said vessel whereby a bed of bottom closure plate provided with a central inlet ?uidized solids on said grid in said vessel will for gaseous ?uids, a top outlet for gaseous ?uid have a greater depth of solids at the center of said from said vessel, a circular dished distribution grid and a better distribution of gaseous ?uid grid supported in the lower portion of said vessel, 55 introduced via said inlet will be obtained in por said grid being arranged in said vessel so that tions of the ?uidized bed other than the center
the central portion of the grid is below the plane
portion thereof.
of the periphery of said grid a distance of the
References Cited in the ?le of this patent 60
UNITED STATES PATENTS
where D is substantially equal to the radius of Number curvature of said grid and also substantially equal 2,443,190 to the diameter of said vessel. 65 2,470,395
Name
Date
Krebs ___________ __ June 15, 1948
Gohr et al ________ __ May 17, 1949