US2538030A - Apparatus for contacting fluent solids with gases - Google Patents

Description

R. H. NEWTON 2,538,030

APPARATUS F'OR CONTACTING FLUENT SOLIDS WITH GASES Jan. 16, 1951 4 Sheets-Sheet 2 Filed Feb. 5, 1945 [NVE/VTR G'ER ,NEM/70N 5y Z, H; 2

ATT/VEY Jan. 16, 1951 R. H. NEWTON 2,538,030

APPARATUS FOR CONTACTING FLUENT SOLIDS WITH GASES Filed Feb. 5, 1945 4 Sheets-Sheet 4 NVENTOR ROGER h. NEWTON A 7' TOR/VE Y Patented Jan. 16, 1951 UNITED STATES PATENT OFFICE APPARATUS FOR CONTACTING FL'UENT SOLIDS WITH GASES Application February 5, 1945, Serial No. 576,306

2 Claims. 1

The present application is in part a continuation of my copending application, Serial No. 426,294, filed January 1G, 1942, now abandoned.

In modern industrial operations a fluent body of solid material is frequently discharged by gravity ilow from a container through a constricted outlet in the bottom of the container. In many instances it is desired that the iuent solid matcrials charged at the top of the container move downwardly through the container at equal rates throughout the transverse section of` the container, This is particularly true in instances where it is desired to have all of the material remain in the container for substantially equal times. t is likewise true in operations in which the solid uent material flows through the container intermittently and it is desired to replace the material in the container with a fresh charge of material, the discharging and charging occurring simultaneously.

In order to obtain equal downward il'ow throughout the transverse section of the container, the bottom wall of the container has frequently been funnelled to the outletat an angle greater than the angle of repose of the solid fluent material. Investigation has shown that unfortunately this does not produce equal downward flow. Channelling occurs because the material at the side of the container does not slide down the bottom wall to a suiiiciently appreciable extent. The greatest flow occurs in a stream vertically above the outlet. Thus, in a vertical cylindrical container having a conical lower wall at an angle greater than the angle of repose, there is a considerable zone of substantially static solid material adjacent the cylindrical wall.

Objects of the present invention are to provide improved systems for containing a moving body of solid fluent material in which the rate of flow is substantially equal throughout the body or bed when the material is moving to and through a constricted outlet at the bottom of the container; and to provide improved means for contacting solid fluent materials with uids, in either gas or liquid state, in which the solid fluent material moves downwardly through a container and out a constricted discharge opening in the bottom thereof, the movement being at equal rates throughout the transverse section of the container.

The present invention has application in a wide variety of uses and is applicable Wherever it is desired to have a body of solid fluent material moving through a container and out of a con- Stricted out1et in the bottom thereof. It is of particular importance in any such instance in which the material should move at equal linear rates throughout the transverse section` of the container. Thus,` in a base exchange system, the Zeolite in granular or other solid uent forni may be introduced at the top of a tank of substantial` elevation and move downwardly as a body therethrough. A solution o material to be contacted with the Zeolite introduced into the tank. The Zeolite is charged at the top of the tank and discharged from a constricted opening at the bottom of the tank after base exchange.

This invention further is applicable in the catalytic neld. Thus, the purpose may be to: heat treat the catalyst, in which event the catalyst is charged to the top of the heat treater and discharged from a restricted opening in the bottom thereof. A treating gas may be introduced into direct contact with the catalyst or a heated gas may be employed in indirect heat exchange relation therewith. In order to eiect uniform treating itis of substantial importance that all of the catalyst remain in the treater for equal residence times, wherefore it is important that the rate of flow downwardly in the treater be equal throughout the transverse section. In catalytic processing, as for example, in catalytic cracking, wherein a body of catalyst flows, downwardly through the catalyst case in direct contact with the oil vapors to be cracked or through the regenerator in direct contact with air it is of considerable importance that the rate of flow be uniform throughout the case. Otherwise some portions of the catalyst will leave the case before suiiicient cracking has been effected in contact therewith for regeneration to be necessary, while other catalyst will have far surpassed its utility without regeneration. In connection with regeneration unequal oW results in non-uniform regeneration.

In accordance with the present invention flow restricting means is positioned in the lower portion of a container through which container a solid uent material ows by gravity, and thence out of a constricted opening in the bottom thereof. The ow restricting means restricts now to the greatest extent adjacent the outlet opening. The restriction to flow decreases with increasing distance from the outlet. The flow restricting means is` so positioned that the angle to the horizontal formed by a line from the outlet opening to the portion of the restricting means most distant from the outlet opening is greater than the angle of repose. Preferably the now restricting means is positioned at an angleat least as great as the angle of repose of the material. The portion of the bottom wall of the container which is below the iiow restricting means may be either horizontal or at an angle. By positioning the bottom wall at an angle directed downwardly toward the outlet, all the material iiowing through the container eventually moves out the outlet. In the case of a horizontal bottom wall an inclined static bed of material reposes on the wall, the material flowing through the container moving over this bed to the outlet.

claims the ilow restricting means is variously reerred to as a grid, a grate, and a baiile, which terms are used herein as synonymous.

For a more complete understanding of this invention reference may be had to the accompanying drawings in which:

Fig. 1 is a vertical section through a portion of an apparatus embodying this invention, on a broken plane showing a central reaction chamber and communicating purging chambers;

Fig. 2 is a section on the line II-II in Fig. l, with some parts removed for purposes of clarity;

Fig. 3 is a detail of a iiow restricting means suitable for use with the apparatus shown in Figs. l and 2;

Fig. 4 is an elevation of a Inodied form of the invention, portions of the front wall being broken away to show internal construction;

Fig. 5 is a section on the line V--V in Fig. 4;

Fig. 6 is a detail of an alternative ow restricting means for use with the form of this invention shown in Figs. fi and 5;

Figs. 7, 8, and 9 are broken vertical sections of other forms of this invention;

Fig. 10 is a section on the line X--X in Fig. 9;

Fig. 1l is a vertical section showing another form of flow restricting means.

In Fig. l there is shown a portion oi an apparatus particularly adapted to catalytic vapor y phase reactions in which the catalyst is alternately on stream and in regeneration and in which the catalyst is purged following both on stream and regeneration, as in hydrocarbon conversion processes. rIhe apparatus lil shown in Fig. l is the lower portion of a system for catalytic conversion, there being shown of the system a casing or container ll and purge chambers I3 and lll. The purge chamber E3 receives catalyst from a regenerating kiln thereabove (not shown) and delivers catalyst purged therein to the upper portion of container Il which provides a reaction chamber l2. The purge chamber it communicates through a restricted outlet with the lower end of casing ll to receive catalyst therefrom. The casing ll has rectangular top and bottom walls l5 and lli, respectively, which are inclined, parallel, and positioned one above the other. The casing l l has four vertical side walls il to 29, inclusive, interconnecting the top and bottom walls. The inclination of the bottom wall IB is preferably at least as great as the angle of repose of the solid fluent material which flows through the container ll, so that no static bed of the material remains on the bottom wall, all of it moving to the constricted outlet 22.

The inlet 2l to casing ll is located along the juncture of the top wall and the side wall il, whereby the material is introduced into the casing l l along a line in proximity to the upper edge of the top wall l5. The outlet 22 from the casing ll is located along the juncture of the bottom wall and the side wall i8 whereby the material is discharged along a line in proximity to the lower edge of bottom wall l.

The material flows through the container as i hereinafter described and eventually reaches the outlet 22. I have found that it is possible to prevent channelling to the outlet by placing a grid 23 in the lower portion of the container which has passages therethrough. The essential characteristic of the grid is that the resistance to iiow is greatest adjacent the outlet and decreases with increasing spacing from the outlet. A preerred manner of obtaining such variation is by ,a having the ratio of solid grid area to passage area In this specification and in the subjoined greatest in proximity to the outlet, and decreasing with increasing lateral spacing from the outlet. This grid, grate or barile may be formed of any suitable material for resisting iiow to varying degrees such as sheet or bar stock.

The grid 23 shown in Figs. l and 3 is located in the lower portion of the container adjacent to and spaced from the bottom wall, providing a small space or passage 24 between the grid and the bottom wall in communication with outlet 22. The grid 23 is formed of a plurality oi fingers 25 providing passages 2t therebetween which passages 255 decrease in area toward the outlet of container l2. In the form here shown, the fingers have straight edges. The grid causes the downward flow of the material throughout the bed above the grid 23 to be equal.

In order to provide for the introduction and withdrawal of reactants from the container Il two sets of deiiectors 2l and 28 are positioned transversely of the catalyst bed, one set near the upper wall and spaced therealong and the other set above and in proximity to plate` 23. The deflectors shown are in the form oi angle irons with the bight portion of the angle upward. With the catalyst moving downwardly a passage remains open beneath each of the deiiectors 2l and 28. Pipes 2Q and 3@ communicate through the side walls of the casing with the passages under angles 2i and 28, respectively. The pipes 29 and the pipes 30 are provided with separate manifolds 3l and 32 to provide for the introduction and withdrawal of fluid reactants. It is preferred to run the reactants and the solid iiuent material counter-currently, to provide for contact of the most active catalyst with the fluid most completely reacted.

'Ehe purge chamber ifi is provided with a plurality or" battles in alternate inclined positions. An inlet 25% is positioned at the lower portion of the purge chamber and an outlet 3l at the upper portion thereof for introduction and eduction of a purging fluid, such as steam. A suitable valve 35i may be provided for controlling the rate of flow from the purging section it. The valve 38 discharges the material into a hopper 39 from which it may be withdrawn by a screw conveyor il@ for return to the regenerator above the purging section i3, and with a valve Lil for removing the material from the system when it is desired to clean the apparatus or replace the Contact material.

With the structure as shown in Figs. l to 3 the solid material discharged from the reactor will v move down through the purge Zone i3 through the container il and into the purge Zone I4. With the valve S closed, 'the apparatus will iill so that it contains a bed of the material throughout the system. When valve 33 opened, the material entering the inlet 2i will move as a stream adjacent to the upper wall I5. From this stream the material will then move downwardly as a bed throughout the horizontal area of the container. The material will pass through the passages 2S in grid 23, through the passage 2t, and out the outlet 22 into the purgezone I4. Any desired iiuid may be contacted, either countercurrently or concurrently with the material by introduction into manifold 3@ or 3i.

In the form of the invention shown in Figs. 4J 5, and 6, several casings or containers, similar to those of Fig. i., are positioned in end to end relationship, the lor-,fer ends and upper ends of adjacent containers being in juxtaposition. In this form, the side walls between adjacent sections are omitted. lThe container is provided with a bottom wall constituted of a plurality of alternately inclined bottom wall sections 42. The upper ends and lower ends of adjacent sections 42 are interconnected, there being disposed at the lower end of each bottom wall section 42 a constricted outlet 43 which may 'contain a valve 44 for adjusting the rate of flow. The container is provided with end walls 45 at the outer ends of the last sections and with side walls 46 interconnecting the end walls and the bottom wall sections. Inlets 47 are provided for the introduction of material throughout or substantially throughout the Width of the container above the upper ond of each bottom wall section. Conveniently an upper wall 48 is provided covering the entire container which is particularly advantageous where it is desired to em ploy the container for a reaction chamber for reactions involving gaseous materials. A plurality of pipes 49 is provided in the upper and lower portion of each section for the introduction or eduction of fluids from the container, 'lhese pipes lil are preferably provided with ports. In order to prevent the entry of the solid material into the pipes through the ports, and to prevent corrosion around the ports which would vary the size of some ci them and cause unequal ilow of iluid, there are provided combination buttons and shields each constituted of a small plate of stainless steel formed to fit the contour of the pipe 49, and which has welded thereto at its ends a second stainless steel plate. The two plates midway their length are spaced apart and in this section are drilled through with an opening of the desired size, This opening is aligned with the port in the pipe and the shields 5!) then welded in place.

A baille 2s is disposed above each bottom wall section 42, which baille, as shown, is similar to that disclosed in Fig. 3. In those instances where two bottom wall sections 42 discharge to a single outlet the baffles 23 thereabove are secured together in coterrninus relationship at a point above the outlet d3.

In Fig. 6 there is shown a detail of a modified form of iiow restricting grid 5i, suitable for use in the structure of Fig. 4. This grid 5! is bent along the line 52, which line lies above the outlet 43. The grid includes ngers 53 which decrease in width stepwise outwardly from the line 52, whereby to provide an increasing ratio of passage area to plate area laterally from the outlet.

After the container has been filled, material introduced through the inlets 47 moves as a stream downwardly until it enters the container. This stream then divides into two streams, each moving laterally over a downwardly moving bed of material within the container with each of these streams being disposed vertically above a bottom wall section. The material so distributed then I moves downwardly through the container as a bed and passes through the passages in bailies 23 and through the passages therebelow to the respective outlet 43.

In Figs. l and 4, forms of this invention are disclosed in which-` relatively shallow beds of Ina-- terial are employed. This invention, however, is applicable in cases where deep beds of material are used, as shown in Figs. 7, 8, and 9.

In the form shown in Fig. 7 a tower of rectangular horizontal section is provided with an outlet 54 which extends substantially from front to back of the tower. In the lower end of the tower there is provided a flow restricting means 5| similar to that shown in Fig. 6 and having the central line 52V lying above the constricted outlet 54. In towers of considerable height it is frequently desirable to employ additional iiow restricting means 55 midway the height of theV tower to overcome the effect of wall resistance to ow. This means 55 may take the form of a grid interposing equal resistance throughout the area of the tower except adjacent the walls, from which the grid is spaced so as to maintain the resultant rate of flow at the walls the same as at points spaced from the wall. The tower is provided with an inlet 56 to which the material may be delivered by an elevator 5l. In order to provide for contact of fluids with the material, manifolded inlet and outlet pipes 58 may be provided on opposite sides of the tower resulting in cross flow of the uid through the solid pulverant material.

With the tower of Fig. '7 loaded with solid fluent material flow through the inlet 5S and the outlet 54 is initiated, the elevator 5l providing additional material to the inlet. From the inlet the material spreads over the surface of the bed in the tower and thence downwardly to the flow restricting means 5l. The material moves through the passages in flow restricting means 5I and thence to the outlet 54. As above explained, due to variation in resistance to flow in the various portions of ow restricting means 5|, the entire body of material in the tower moves downwardly at substantially equal rates. With :a flat bottom to the tower, as shown, a static bed will form on the bottom wall over which the moving material will flow from the passages in the grid 5| to the outlet 54, the grid 5| being positioned so that the angle between a line from its outer edge to the outlet and the horizontal is greater than the angle of repose.

While the invention has been illustrated in Figs. l, 4, and 7 in connection with rectangular containers, it is likewise applicable to circular containers, as shown in Figs. 8 and 9. In Fig. 8 a circular tower is provided with an inlet 59 in the upper end thereof and with an outlet 6U having a valve 6l therein at the lower end of the tower. A conical bottom wall 62 is positioned centrally in thelower end of the tower with its apex upward and with its lower edge spaced equally from the inner wall of the tower whereby to provide a circular constricted outlet 63 from the tower. Spaced above and adjacent to the conical wall 62 there is a grid 6d having passages therethrough. This grid in general extends to the outer wall of the container so as to restrict to the greatest extent the passage of material therethrough from above the outlet. The passage area through the grid 64 increases relative to residual grid area toward the center. The angle between a line from the center portion of grid 64 to the circular outlet and the horizontal is at least as great as the angle of repose of the material to be passed through the tower. As shown in Fig. 8 pipes 65 may be provided at the top and bottom of the tower for the introduction and eduction of fluids to be contacted with the material in the container. The operation of the structure shown in Fig. 8 is the same as that in the forms heretofore described.

Fig. 9 illustrates another form of circular container embodying this invention. In this form a conical deflector 66 is secured in the upper end of the circular tower with its apex directed upwardly and its lower edge spaced from the internal wall of the container providing an inlet 6l about deiiector B6. The conical deflector 66 causes feeding of material to the tower at the periphery thereof. In the lower end 0f the tower there is a discharge B8 located centrally. A conical grid 69 is positioned with its apex downwardly at a position above the outlet. The grid G9, shown in detail in Fig. l0, is provided with passages therethrough with the lowest*l ratio of passage area to grid area at the center of the grid and with the ratio increasing toward the periphery of the container. In order to effect this result the passages may all be the same size, but with fewer passages provided per square foot of grid area toward the center thereof, or the same number of passages per square foot of grid may be employed but with the passages increasing in size toward the center. Likewise a combination of these two effects may be employed. An alternative form of grid is disclosed in Fig. 11 applied to the form of this invention disclosed in Fig. 9. In this form of grid a plurality of bars li! formed as circles are secured together to dene generally a cone. The spacing between adjacent bars is least near the apex of the cone and greatest toward the upper edge of the cone. It is obvious that in any of the species shown, this general type of grid may be employed, the grid being constructed in a specific form depending upon the type of container with which it is to be employed.

The angle of repose of any material is readily measurable. In general angles of repose of solid fluent materials lie within the range of about 25 to about 60.

My copending application Serial No. 576,307, filed of even date herewith, now Patent No. 2,490,828, is directed to subject matter herein disclosed but not here claimed specically.

I claim as my invention:

l. In an apparatus of the class described, the combination which comprises a container having a vertical cylindrical side wall and a circular bottom wall within the side wall and with its circular edge equally spaced from the cylindrical wall whereby to provide a constricted outlet from the container' along a circular line, said container having an inlet for the introduction of said material thereinto centrally in the upper portion thereof, and a conical grid having openings therethrough providing passages for said material, said conical grid having its walls extending inwardly and upwardly from above said outlet, the ratio of the area of solid grid surface to the area of openings through the grid being greatest adiacent the outlet and decreasing toward the center of said container, whereby material introduced into said container through said inlet, after distribution over the upper surface of a bed of the material, moves downwardly throughout the area of said bed at substantially equal rates, through the conical grid and thence moves at an angle between the conical grid and the bottom wall to and out the outlet.

2. In apparatus of the character described, a container defining a reaction zone and having upper and lower inlet and outlet openings, said container being adapted to receive solid fluent material which passes downwardly therethrough and then therefrom by way of said outlet opening, and a grid positioned adjacent said outlet opening in the path of fluent material passing thereto and having openings therethrough providing passages for said fluent material, said grid, throughout its area, being disposed in uniform sloping relation with respect to the vertical axis of said reaction Zone and intersecting said vertical axis at only one level, the ratio of the area of solid grid surface to the area of openings through the grid being greatest adjacent the outlet opening and decreasing in a direction extending therefrom .Thereby fluent material introduced into said container through said inlet opening, after distribution over the upper Surface of a bed of the fluent material, moves downwardly throughout the area of said bed at substantially equal rates, through the grid and thence from said container by way of the outlet opening.

ROGER H. N'EJNTON.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 1,617,960 Muller Feb. 15, 1927 FOREIGN PATENTS Number Country Date 703,784 France Feb. 10, 1931

Claims (1)

1. IN AN APPARATUS OF THE CLASS DESCRIBED, THE COMBINATION WHICH COMPRISES A CONTAINER HAVING A VERTICAL CYLINDRICAL SIDE WALL AND A CIRCULAR BOTTOM WALL WITHIN THE SIDE WALL AND WITH ITS CIRCULAR EDGE EQUALLY SPACED FROM THE CYLINDRICAL WALL WHEREBY TO PROVIDE A CONSTRICTED OUTLET FROM THE CONTAINER ALONG A CIRCULAR LINE, SAID CONTAINER HAVING AN INLET FOR THE INTRODUCTION OF SAID MATERIAL THEREINTO CENTRALLY IN THE UPPER PORTION THEREOF, AND A CONICAL GRID HAVING OPENINGS THERETHROUGH PROVIDING PASSAGES FOR SAID MATERIAL, SAID CONICAL GRID HAVING ITS WALLS EXTENDING INWARDLY AND UNWARDLY FROM ABOVE SAID OUTLET, THE RATIO OF THE AREA OF SOLID GRID SURFACE TO THE AREA OF

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