HU181508B - Radial-flow moving-bed apparatus for contacting fluid and solid material - Google Patents

Abstract

The present invention relates to a radial flowing mobile unit to contact solid and liquid. The radial flow is a liquid-solid contact devices can be used in many areas of industrial processes. Examples include various hydrocarbon converters radial flow reactors used in the process. These are processes or processes include, for example, normal paraffins isomerization, dehydrogenation of normal paraffins, and distillation products obtained by the evaporation of crude oil reforming. The radial flow reactors are different reagents flow radially from the central crankshaft of the reactor to the district

Description

BACKGROUND OF THE INVENTION The present invention relates to a radial flow movable bed apparatus for contacting solids and liquids.

Radial-flow liquid-solid contact devices can be used in a variety of industrial processes. These include, for example, radial flow reactors used in various hydrocarbon conversion processes. These processes or processes include, for example, isomerization of normal paraffins, dehydrogenation of normal paraffins, and reforming of batch distillation products obtained by the evaporation of petroleum. In radial flow reactors, the various reagents flow radially from the central major axis of the reactor towards the periphery.

The device according to the invention belongs to the group of reactors where the reagent flows inward. This means that the reagent flows inward from the annular distribution space towards the reagent collecting cylinder. The central reagent collecting space is surrounded by an internal sieve for retaining the catalyst. The inner sieve is generally referred to as the middle tube of the reactor.

Radial flow systems are also used in other contact devices, such as adsorbent chambers and operators. Due to the fact that the apparatus is used as a mobile bed reactor according to the invention, it can also be used as a mobile bed regenerator to decarbonise, reduce or halogenate the catalysts or adsorbents used.

The term "moving bed" here refers to a system in which a particulate material is formed, the granules are placed on top of each other to form a dense bed, and the bed particle set is gradually renewed by removing the spent particles from the lower part and replacing them regenerated particles are fed. Thus, the device of the invention makes contact with a non-boiling or fluidized bed. The device can be used with both vapor and liquid media.

To date, granules have been recovered from the annular beds through a series of centrally located apertures at the bottom of the reactor vessel. By "centrally located apertures" is meant apertures which, together with their associated particle or catalyst particle exhaust ducts, are located approximately midway between the two grain retaining screens or sieves, or approximately 50% of the distance between the screens. The outlet conduit is often covered by a cap or a reverse cone as disclosed in U.S. Patent Nos. 3,706,536, 3,785,963 and 3,854,887. The purpose of using the caps and placing the drain pipe in the middle is to promote the uniform removal of the particles from all parts of the bed. With this known design, it was hoped that the particles adjacent to the sieves or sieves could be recovered at a uniform rate.

Experience has shown that known solutions cannot uniformly recover the catalyst material. In fact, quite a large amount of catalyst or particulate remains inside the device and does not move away from its once occupied position. This residual amount of grain does not perform its function and also affects the performance of the device. In addition, it has been found that the lower part of the vessel has an internal retaining bar

30'Steering grain zone remaining next to a 30 'sieve or sieve begins, especially when steam or liquid is flowing through the grain bed at a higher rate. There is no doubt that this is - at least in part - caused by the inward flow of steam.

Another undesirable phenomenon observed in the use of known types of particle recovery solutions is that the finely divided particles formed by abrasion during normal movement of the particulate material accumulate in the remaining particle zone. These fine particles are moved by the inward-flowing steam towards the stationary stagnant zone, but it is not carried away from here as it would be if no such stagnant zone existed. As a result, some of the small conduits conducting the vapor may be clogged, resulting in a greater pressure drop at the bottom of the grain bed than at the top. This degrades the uniform flow rate required for all parts of the annular particle bed. As a result, the actual space velocity in the reactor is higher at the top than at the bottom.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a moving bed radial flow solid-liquid contact device. It is a further object of the present invention to provide a moving bed radial flow reactor with a minimal amount of stagnant catalyst remaining in place and which reduces the accumulation of stagnant catalyst particles on the middle tube surface as steam flows inward.

According to the invention, the object is solved by a radial-flow movable bed apparatus in which the vertically placed vessel has an interior space defined by the inner surface of a cylindrical sidewall and is divided into upper and lower portions inside the outer vessel radially from the inner surface. at a predetermined distance, a first vertical grain retaining screen is disposed so that a fluid distribution space is formed between it and the outer vessel wall, a second vertical grain retaining screen disposed radially at a first radial distance therefrom. an annular particle retention space having a top and a lower end formed between the second particle retention screen and a cylindrical fluid collection space inside the second particle retention screen; a plurality of grain pellet feeding tubes located at the upper end of the outer vessel and communicating with the upper end of the annular grain retention space; a fluid inlet line communicating with the fluid distribution space; a fluid discharge line communicating with the fluid collecting cylinder; between the first and the second particle retention screen, at the lower end of the annular particle retention space, a particle recovery device is provided. The apparatus is characterized in that the granule recovery device has a plurality of granulator circuits distributed around the second granule retaining sieve and each of the serum recovery tubes having an open upper end that is connected to the annular granule retention space, and further comprising having an upper open end towards the screen and a lower end connected to the upper end of the recovery hopper, the upper end of each hopper being located between the lower end of the hopper and the inner screen of the second hopper and finally the upper end of each hopper having a larger cross section end, and that the hopper is positioned at an angle of 5 'to 60' to the horizontal.

The invention will now be described in more detail with reference to an exemplary embodiment thereof, of which:

Figure 1 is a sectional view of an exemplary embodiment of the device of the invention;

Figure 2 is an enlarged sectional view of the lower right portion of the device of Figure 1;

Figure 3 is a plan view of the hopper; Figure 4 is a sectional and plan view detail of a preferred embodiment of a grit retaining screen or screen and a hopper;

Figure 5 is a side view of an exemplary embodiment of the hopper;

Fig. 1 shows a moving bed radial flow reactor surrounded by an outer vessel 1 which is a preferred embodiment of the device according to the invention. The outer container 1 consists of a vertical cylinder closed by an upper lid portion 36 and a lower lid portion 37. The first catalyst retaining screen or screen 2 is also cylindrical, and the second catalyst retaining screen 3 or screen is also cylindrical. The outer and inner screens 2 are arranged concentrically around the central axis of the reactor. The outer surface of the outer sieve 2 and the cylindrical inner surface of the outer vessel 1 delimit an annular distribution space 38 containing liquid or reagent into which the reagent flows through the conduit 6. Between the outer screen 2 and the inner screen 3 there is an annular catalyst bed 4. This catalyst bed may be batch filled with fresh catalyst coming from the 5.5 'tubing introducing the catalyst. In the figure, for the sake of simplicity, only two catalyst feed pipes 5, 5 'are shown, but at least eight of them are normally used. Preferably, the upper end of the perforated portion of the outer and inner screens is below the upper inner surface of the outer vessel 1 and the catalyst bed is closed by a non-perforated disc-shaped plate 10.

The reagent travels inwardly through the catalyst bed 4 and enters the fluid or reagent cylindrical space. Reagents and reaction products are removed from the reactor via line 7. The reagent collecting chamber is closed at the top with a circular topsheet 9. The spent catalyst is recovered from the reactor by means of the collecting hopper 8, 8 '. The upper end of the collecting hopper 8, 8 'is open towards the inner screen 3 which retains the catalyst. The catalyst flows through this upper open end and is recovered in an annular space much closer to the inner screen than to the outer screen. The lower end of the collecting hopper 8, 8 'is connected to a catalyst recovery pipe 39, 39'. These pipelines 39,39 'are arranged around the inner screen 3 and pass through the lower lid portion 37. During the operation of the reactor, the catalyst collecting hopper 8,8 'and the tops of the catalyst recovery tubes 39, 39' are filled with catalyst material. The use of the device according to the invention is, of course, not limited to the use described above as a reactor.

Figure 2 is a side elevational view of the recovery hopper 13 for catalyst recovery. The lower end of the hopper 13 is connected to a catalyst recovery pipe 12. This vertical pipeline 12 extends through the horizontal outer wall 11 of the reactor and is connected to a series of valves or a catalyst collecting hopper, depending on the configuration of the apparatus. The pipeline may also feed the catalyst directly into another reactor in the reactor group. The hopper 13 is positioned such that its open upper end opens toward the inner screen 40 retaining the catalyst. The opening 41 is located near the inner screen 40 and faces inwardly. The catalyst retaining outer screen 14 is closer to the lower end of the hopper 13

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Of the many holes in the sieves, for the sake of simplicity, only a few are indicated. As can be seen from the drawing, the collecting hopper 13 is preferably formed of parallel, flat top and bottom hole-free sheets. These sheets are inclined upwards from the horizontal at an angle "a" from the lower end of the hopper 13. The sides of the hopper 13 are formed by opposing flat side panels.

Figure 3 is a top view of the catalyst hopper 13. This hopper 13 is similar to that shown in Figure 2. The lower end of the collecting hopper 13 is connected to the upper end of the catalyst recovery pipe 12. The upper edge 17 of the upper plate 17 of the hopper 13 is further away from the inner screen 40 retaining the catalyst than the upper edge 18 of the lower plate. Because of the substantially triangular plates, the hopper 13 has a larger cross-sectional area than the lower one.

Figure 4 shows curved sheet edges forming the upper end of the catalyst collecting hopper 19. In this preferred embodiment, the lower end of the collecting hopper 19 is positioned so as to guide the catalyst particles into a conduit 20 for recovering the catalyst. Here, too, the top edges of the sheets are arranged horizontally behind each other to allow the particles to enter the hopper 19. In this embodiment, the upper edge 21 of the upper sheet is further away from the inner retaining screen 35 than the upper edge 23 of the lower sheet. In the preferred embodiment, the upper edge of the topsheet 22 and the upper edge of the bottomsheet are curved with a radius of curvature determined by the radius of the inner screen 35 such that the radial distance between the inner screen 35 and the two edges is all the same along a wind. Figure 4 also shows an outer screen 44 with recesses positioned adjacent the cylindrical outer wall 43 of the reactor.

Figure 5 is a top view of the upper end of the catalyst hopper 13. This hopper 13 is more similar to the hopper shown in Figures 2 and 3 than the curved hopper hopper shown in Figure 4. The lower end of the hopper 13 is connected to a conduit 12 which recovers the catalyst. The edge 17 of the top panel is secured to vertical side walls 27 and 27 'opposite to the edge 18 of the bottom panel. The upper end of the hopper 13 is therefore delimited by upper edges 17, 18 and side walls 27, 27 '.

The particulate material used in the apparatus is preferably a hydrocarbon conversion catalyst, however, it may be an adsorbent containing activated carbon, zeolite or alumina, and a sulfur compound or a halogen-containing chemical may be used to remove water in the treatment of gas streams. The particulate material may also be a solid acceptor that can be used to remove sulfur dioxide from flue gas streams as described in U.S. Patent Nos. 3,776,854 and 3,832,445. The particles of the particulate material are preferably spherical and have a diameter of between 0.15 cm and 1.25 cm. The terms "catalyst" and "grain" were used interchangeably throughout this description to describe various parts of the device. However, the use of a word does not limit the invention to a narrower scope of the word, or to a narrower meaning thereof. The catalyst used in the apparatus may preferably contain an inorganic oxide carrier such as alumina or silica with a catalytically effective amount of metal or metal oxide. One or more metals may be selected from the group consisting of nickel, cobalt, iron, platinum, tin, palladium, manganese or magnesium.

The outer container 1 is preferably made of a suitable metal, such as carbon steel or acid-proof steel, but it can also be formed of other materials, such as fiber-reinforced plastic, when temperature, pressure, etc. conditions allow their use.

The inner and outer sieve or screen retaining the particles or catalyst are preferably made of wedge-shaped wire and the wire cross-section is reduced laterally opposite to the particles. As a result, self-cleaning surfaces are obtained, which means that any grain or similar material passed through the screen openings falls freely on the other side of the screen. The wedges of the wedge cross-section are preferably in a vertical position so as to minimize the abrasion effect of the catalyst as the catalyst moves downward. The particle retaining outer screen or sieve has a cylindrical design, but may be provided with recesses, to form an annular fluid distribution space, as shown in Figure 4.

The contact device according to the invention has a plurality of grain pellet feed pipes 5, 5 'which extend through the upper lid portion of the outer container 1 and are connected to an annular space holding the particles. Typically, 6 to 10 such feed lines are sufficient to properly distribute the particulate material. Preferably, the upper part of the inner and outer screens or screens of the particulate retaining pad has a perforated section whose sealing effect prevents a portion of the liquid from flowing through the void spaces which may be formed above the particles. The outer and inner sieve or screen may be closed as shown in Figure 1 or extend to the inner surface of the outer container 1. The feed lines may normally be connected to a valve that controls the particle fill. The feed pipes may also be connected to a dispensing vessel which may be used to distribute the particles. The feed pipelines can also be connected to their discharge pipelines in stacked vessels or reactors.

In a preferred embodiment of the device according to the invention, there are a plurality of grain collectors, which are arranged at the bottom of the device, circumferentially around the middle tube so that the ends of the adjacent collectors are in contact or very close to each other (within 15 cm). They form an annular catalyst collecting zone which is evenly distributed around the center tube. The width of this space is equal to the distance between the center tube and the upper edge of the manifolds, which is preferably less than 30 cm. It is very advantageous if the distance between the upper edges is less than 10 cm and the distance between the lower edges is less than 5 cm when using a curved collector hopper. If the edges of the collecting hopper are straight, then the average width should be determined, since the distance of each edge from the center tube varies from point to point. Such a hopper is shown in Figure 3. It is preferable that the upper and lower edges of the collecting hopper sheets are curved and have a curvature corresponding to the curvature of the central tube, since the distance between the central tube and the collecting hopper is thus uniform throughout. Of course, if desired, edges other than those shown in the drawings may be used.

Each hopper is hollow and has the shape of an internal space corresponding to the external shape of the hopper. Preferably, the top and bottom panels and side walls defining the hopper are not perforated. However, these elements of the collecting hopper may be relatively porous in order to facilitate the circulation of liquid or vapor. In many cases this may be desirable in order to prevent material retention or fluid retention in the recovery tubes. The inside of the manifolds has a larger cross-section at the upper end near the center pipe than the pipe to recover the particles3

At bottom end of connector to -3181508. The hopper collectors are essentially funnel-like collectors. To facilitate the collection of the granules, the upper horizontal edge of the bottom plate of the hopper is closer to the center tube than the upper edge of the top plate, as shown in Figures 2 and 3.

When the device of the present invention is used as a reactor, the hopper deflectors for grain or catalyst are inclined at an angle of 5 ° to 60 ° with respect to the horizontal. This angle is depicted in Figure 2 as the angle "a". This angle is preferably between 15 ° and 45 ', but most preferably at 30 °. It is also advantageous if the top and bottom panels of the collecting hopper are parallel and are thus at an angle to the horizontal. However, this is not essential and the hopper can be tapered vertically. The hopper may be surrounded by a particulate material that passes through the apparatus, but may be surrounded by neutral spacers, such as ceramic spheres, which are located at the bottom of the vessel. Multiple supports can be placed around and under the hopper hopper to prevent movement and deformation during operation.

Claims (2)

Patent claims A radial flow movable bed apparatus for contacting a solid and a liquid having an inner space defined by an inner surface of a cylindrical side wall of a vertically positioned vessel, divided into upper and lower portions of the outer vessel (1), at a radially defined distance from the inner surface, a first vertical particle retaining outer screen (2,14,44) is disposed with a fluid distribution space (38) between it and the outer vessel (1) wall, the first particle retaining outer screen (2, 14, 44) a second vertical grain retaining inner sieve (3,35,40) is disposed within a radially defined distance therebetween so that an annular grain retaining space having an upper and a lower end is provided between the first and second grain retaining screens, and a second inner grain retaining screen. 3,35,40) inside a cylindrical fluid there is a collecting space; in the upper part of the outer vessel (1) there are provided a plurality of grain pellet feeding conduits (5, 5 ') communicating with the upper end of the annular particulate retention space, while the liquid inlet conduit (6) and the liquid distribution conduit (38); ) And 5 is connected to a fluid collecting cylinder; and finally, between the first and second particle retention screens (2,14, 44 and 3, 35,40), a particle reclaiming device is provided at the lower end of the annular particle retention space, characterized in that 10 second particle retaining inner screens (3, 35, 40) having circularly distributed particle reclaiming tubing (12,20,39, 39 '), each of the particle reclaiming tubing (12, 20, 39, 39') communicating with an annular particle retention space upper end, in addition to that 15, the granule recovery device has a particle retention hopper (13, 19), each hopper (13, 19) having an upper open end opening toward the second particle retaining inner screen (3,35,40) and a particle recycle conduit (12,20, 39, 39). ') has a lower end connected to its upper end, each The upper end of the collecting hopper (13, 19) is disposed between the lower end of the collecting hopper (13,19) and the second grain retaining inner screen (3, 35,40), and finally the upper end of each collecting hopper (13, 19) has a larger cross-section. like the lower end and the hopper (13,19) to the horizontal 5 'and 60' They are inclined at an angle of 25. An embodiment of the device according to claim 1, characterized in that the first particle retaining outer screen (2, 14) is cylindrical and the liquid distribution space is annular. Embodiment according to claim 1 or 2, characterized in that the upper end of the granule deflector hopper (19) has an upper curved edge (21) which is substantially uniformly spaced from the second grain retaining inner screen (35). further, that the second grain retaining inner screen (35) and the upper hopper (19) Between its 35 curved edges (21), there is an annular vertical channel that passes the particles. An embodiment of the device according to claim 3, characterized in that the hopper deflecting the granules (19) is inclined at an angle of 15 ° to 45 ° with respect to the horizontal plane. 40 are placed. 2 drawings, (5 figures) Director of Economic and Legal Publishing House 84.5403.66-4 Alföldi Nyomda, Debrecen Responsible manager: István Benkő director