Dispersion plate for forming a fluidized bed and fluidized bed dryer

Abstract

The present invention addresses the problem of providing a distribution plate used to form a fluidized bed in a reactor such as a dryer or an incinerator, the distribution plate having improved drying efficiency and operational efficiency by achieving both discharge performance when operation ends and stable fluidized bed formation during operation, and to this end, a distribution plate 1 for forming a fluidized bed comprises a base plate 2, a plurality of small holes 3 provided in the base plate, and a chimney deck in which chimneys 4 are disposed in each small hole, wherein the chimneys include a slit-shaped first opening portion 7A that opens in a prescribed direction, and a second opening portion 7B that opens in a different direction in a position higher than the first opening portion.

Description

[Technical Field]

[0001] The present invention relates to a dispersion plate used to form a fluidized bed of powder or granular material in a broad range of reactors such as dryers, coolers, and incinerators, and to a fluidized bed dryer using the dispersion plate. [Background technology]

[0002] A fluidized bed dryer blows hot air upward from a dispersion plate such as a perforated plate to fluidize the powdered or granular raw material, thereby efficiently bringing the powdered or granular raw material into contact with the hot air and moving the evaporated material. This makes it an efficient drying device, and since the device itself has no moving parts, it is easy to maintain.

[0003] Patent Document 1 discloses a perforated plate for a fluidized bed dryer in which, when small holes of any shape are drilled in a material plate, the members corresponding to the holes in the material plate are deformed so as to open to one side to form the open portions and roof-like protrusions covering the holes, as well as protrusions below the open portions, and the open portions are oriented in the direction of powder flow.The document also discloses that a perforated plate of this configuration has the advantages of preventing powdered or granular raw materials from falling below the perforated plate and of allowing the direction in which the powdered or granular raw materials are blown up to be freely selected in advance.

[0004] Patent Document 2 discloses a gas-blowing perforated plate for fluidized beds, in which a large number of openings, each with an opening on one side and another with an opening on the opposite side, are arranged in pairs on a metal plate, and the opening area of ​​the opening on one side is 1.1 to 1.5 times the opening area of ​​the opening on the opposite side. It also describes that this gas-blowing perforated plate for fluidized beds can suppress the air slide phenomenon even when used under high pressure loss conditions (thick powder bed conditions), and can provide a perforated plate with the minimum necessary horizontal vector (propulsion action) to completely discharge powder from the bed in a short time at the end of operation.

[0005] Furthermore, the specification of Patent Document 2 describes a perforated plate corresponding to the prior art, which has slit-shaped openings facing in one direction for the purpose of smoothly discharging powder from the bed at the end of operation. However, when such a perforated plate is used in a region with high (high) pressure loss, a horizontal airflow as strong as or even stronger than that of an air slide is formed above the perforated plate. This causes powder introduced into the bed to be carried forward by this horizontal airflow, making it extremely difficult to form a fluidized powder bed at the introduction point. In contrast, the specification of the present invention describes that when air is blown into such a perforated plate with openings in two directions, the air ejected from one opening and the air ejected from the paired opening in the opposite direction collide in the fluidized bed, and the left and right vectors are canceled out, resulting in an airflow with a horizontal vector equal to the difference between the amount of air ejected from the opening in one direction and the amount of air ejected from the paired opening in the opposite direction, with the majority of the airflow having an upward vector.

[0006] Patent Document 3 discloses an air distribution device for a fluidized bed incinerator, comprising multiple air distribution blocks made of refractory material and perforated plates arranged below the air distribution blocks, the air outlets of the air distribution blocks facing approximately horizontally, the air flow paths in the air distribution blocks having a substantially uniform cross-sectional area without any intermediate restrictions, the perforated plates consisting of multiple tiers of perforated single plates arranged approximately parallel with gaps in the vertical direction, the small holes in adjacent perforated single plates in each tier being arranged horizontally apart so as not to overlap vertically. It is stated that this type of air distribution device prevents clogging, enables uniform distribution, and is free from the risk of corrosion.

[0007] Patent Document 4 discloses an air cap provided on a blower plate used in a circulating fluidized bed boiler system. It describes that this air cap includes a cap body and a cap, the cap body is provided with a spiral exhaust port, the cross section of the cap is arc-shaped, a mesh-like blocking sheet is provided at the spiral exhaust port, and the diameter of the cap body is larger than the diameter of the air vent. It also describes that by using such an air cap, the spiral exhaust port formed in the cap body can form a spiral airflow, while at the same time, uniformly distributing the airflow, and the placement of the mesh-like blocking sheet on the cap and the exhaust port can effectively block foreign matter (for example, coal slag generated by coal combustion, unburned coal, etc.). [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Japanese Patent Publication No. 49-34901 [Patent Document 2] Japanese Patent Publication No. 9-89457 [Patent Document 3] Japan Utility Model Publication No. 60-9558 [Patent Document 4] Chinese Patent No. 108167824 Summary of the Invention [Problem to be solved by the invention]

[0009] The object of the present invention is to provide a dispersion plate for forming a fluidized bed, which has been developed in consideration of the various background technologies described above, and which achieves both the dischargeability of powder and granular material at the end of operation and the stable formation of a fluidized bed during operation, thereby improving drying efficiency and work efficiency. [Means for solving the problem]

[0010] In order to achieve the above object, the present invention provides a dispersion plate for forming a fluidized bed and a fluidized bed dryer as described in the following [1] to [8]. [1] A container having a powder / granule inlet at one end and a powder / granule outlet at the bottom of the other end.A dispersion plate used to form a fluidized bed of powder or granular material, The dispersion plate includes a substrate, a plurality of small holes provided in the substrate, and a chimney deck in which a chimney is disposed in each of the small holes, The chimney mentioned above is The center of the opening is directed toward the discharge port for the powder and granules to be treated. a first opening and a height position above the first opening The center of the opening is directed in the opposite direction to the opening direction of the first opening. and a second opening. A dispersion plate that forms a fluidized layer. [2] The chimney comprises a cylindrical tower portion and a roof portion that closes the upper end opening of the tower portion, and the first opening and the second opening are formed in the peripheral wall of the tower portion. A dispersion plate for forming the fluidized bed according to [1] above. [3] The first opening and the second opening are each formed in a slit shape parallel to the substrate. A dispersion plate for forming the fluidized bed according to [1] above. [4] The first opening and the second opening are each formed by two slit-shaped openings whose width gradually narrows, with the wider slit width sides adjacent to each other. A dispersion plate for forming the fluidized bed according to [1] above. [5] The second opening is formed at a position 5 mm or more higher than the height position of the first opening. The above-mentioned [ 1 ] A dispersion plate for forming a fluidized bed according to the above. [6] The first opening is formed as a slit having a width of 1 to 5 mm and a length of 15 to 180 degrees around the central axis of the cylindrical tower. The above-mentioned [ 2 ] A dispersion plate for forming a fluidized bed according to the above. [7] The chimney deck is formed evenly and without bias on the base plate in a staggered or parallel arrangement. A dispersion plate for forming the fluidized bed according to [1] above. [8] A fluidized bed dryer using the dispersion plate that forms a fluidized bed according to any one of [1] to [7] above. [Effects of the Invention]

[0011] According to the dispersion plate of the present invention, the first and second openings formed in the chimney are formed at different heights and directions, so the vectors of the airflow supplied from each opening are not canceled out, and the airflow from the opening closer to the substrate (the opening with the lower height) provides a discharge function at the end of operation and makes it difficult for phenomena such as air sliding to occur during operation. Therefore, the uniform airflow maintains a stable fluidized bed regardless of the layer thickness, enabling improved drying efficiency and work efficiency. [Brief explanation of the drawings]

[0012] [Figure 1] 1A and 1B are diagrams showing an embodiment of a dispersion plate according to the present invention, in which (A) is a plan view and (B) is a front view. [Figure 2] These figures show the basic positional relationship between the first opening and the second opening formed in the chimney, where (A) is a cross-sectional view with different cut surfaces on the left and right, (B) is a front view, (C) is a right side view, and (D) is a left side view. [Figure 3] FIG. 1 is a perspective view showing an embodiment of a chimney deck on which a chimney is arranged. [Figure 4] FIG. 1 is a front view showing one embodiment of a chimney deck. [Figure 5] FIG. 2 is an enlarged cross-sectional view of a portion of the chimney deck taken along line II in FIG. 1. [Figure 6] 2 is an enlarged cross-sectional view of a portion of the chimney deck taken along line II-II in FIG. 1. [Figure 7] 3 is a cross-sectional view of the chimney deck taken along line III-III in FIG. 4. [Figure 8] 4. FIG. 4 is a cross-sectional view of the chimney deck taken along line IV-IV in FIG. [Figure 9] 1 is a side view conceptually showing one embodiment of a fluidized bed dryer according to the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0013] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of a dispersion plate for forming a fluidized bed and a fluidized bed dryer according to the present invention will be described in detail with reference to the drawings.

[0014] Figure 1 shows one embodiment of a dispersion plate according to the present invention. The dispersion plate 1 according to the present invention is composed of a base plate 2, a plurality of small holes 3 formed in the base plate 2, and chimneys 4 arranged in each of the small holes 3. In this specification, a deck on which chimneys (chimney structures) are arranged is referred to as a chimney deck.

[0015] The substrate 2 has a structure in which a heat insulating material 2B is bonded to a sheet plate 2A (see FIG. 3). The sheet plate 2A is formed from a flat metal plate, for example, stainless steel or carbon steel. The heat insulating material 2B can be made of any material that is heat resistant and has lower thermal conductivity than metal, for example, perlite or glass wool. The thickness of the substrate 2 is designed to be optimal depending on the type and size of the reactor used, and the materials of the sheet plate 2A and the heat insulating material 2B used, and is not particularly limited. For example, the substrate 2 can be made by bonding a 20-30 mm thick heat insulating material 2B containing perlite to a 5-10 mm thick stainless steel sheet plate 2A.

[0016] A plurality of small holes 3 are formed on the surface of the substrate 2, penetrating the surface. The small holes 3 may be formed evenly and uniformly across the surface of the substrate 2, and may be arranged in a parallel row or in a staggered arrangement as shown in FIG. 1. The size and spacing of the small holes 3 are also designed to be optimal depending on the type and size of the reactor used. For example, circular small holes 4 with a diameter of 30 to 70 mm may be arranged in a staggered arrangement with L1 of 60 to 140 mm and L2 of 30 to 50 mm as shown in FIG. 1.

[0017] Each small hole 3 is provided with a chimney deck on which a chimney 4 is arranged. The chimney 4 is made of a heat-resistant material, preferably titanium, polytetrafluoroethylene (PTFE), or stainless steel. The chimney 4 is made of a tower section 4A and a roof section 4B that closes the upper opening of the tower section 4A (see Figures 3 and 4). The tower section 4A and the roof section 4B may be formed integrally, or may be separate pieces joined together. When formed integrally, they can be produced by cutting or 3D modeling using a 3D printer.

[0018] The shape of the chimney 4 is determined by the shape of the small holes 3 drilled in the substrate 2; if the small holes 3 are circular, the chimney 4 will have a cylindrical tower section 4A; if the small holes 3 are square, the chimney 4 will have a rectangular tubular tower section 4A. The chimney 4 can be inserted into the small holes 3, and the diameter of the cylindrical tower section 4A is, for example, in the range of 25 to 70 mm. From the viewpoint of thermal insulation, the chimney 4 preferably has a hollow structure (double-wall structure) with a closed space inside; in the illustrated embodiment, the roof section 4B and the tower section 4A, which is the portion protruding above the substrate 2, are formed into a hollow structure (double-wall structure) with a closed space 8 inside (see FIGS. 5 and 6).

[0019] The chimney 4 is inserted into a small hole 3 formed in the base plate 2 and fixed to the base plate 2 to form a chimney deck. In the illustrated embodiment, a male screw 5 is formed on the outer peripheral surface of the lower part of the cylindrical tower section 4A, and the chimney 4 is fixed to the back side of the base plate 2 by a lock nut 6 that screws onto the male screw 5 (see Figures 3 and 4). However, the method of fixing the chimney 4 to the base plate 2 is not limited to this.

[0020] An opening 7 is formed in the peripheral wall of the tower section 4A of the chimney 4, which is disposed in the small hole 3 and protrudes above the substrate 2. The opening 7 is formed into a first opening 7A and a second opening 7B, which are formed at different heights and in different directions. That is, the first opening 7A and the second opening 7B are formed at different height positions and facing in different directions (see FIGS. 2 to 8).

[0021] The basic positional relationship between the first opening 7A and the second opening 7B formed in the chimney 4 is shown in FIG. 2. As shown in FIG. 2, the first opening 7A is formed at a low position close to the surface of the substrate 2. The opening direction is such that the center of the opening faces right in FIG. 2. The second opening 7B is formed at a higher position above the first opening 7A with the center of the opening facing left in FIG. 2. The second opening 7B may be formed at a higher position than the first opening 7A, but is preferably formed at a position 5 mm or more higher, and more preferably formed at a position 10 mm or more higher. The opening directions of the first opening 7A and the second opening 7B do not have to be completely aligned, but it is most preferable that the opening directions are opposite and the opening angle ranges do not overlap, as shown in FIG. 2.

[0022] The first opening 7A and the second opening 7B will be described in more detail with reference to the drawings of the embodiment of the chimney 4 shown in FIGS.

[0023] The first opening 7A is formed at a position h × (1 / 2) or less from the base plate 2, preferably h × (1 / 3) or less, where h is the height of the highest part of the tower section 4A relative to the top surface of the base plate 2 (see FIG. 4). The first opening 7A has a long, narrow slit shape parallel to the base plate 2, from the viewpoint of discharging the powder and granular material at the end of operation. The slit width w of the slit-shaped first opening 7A is preferably 1 to 5 mm, more preferably 1 to 3 mm. The slit width w does not need to be uniform and may vary. For example, as in the illustrated embodiment, the slit may have a gradually narrowing width w. By gradually narrowing the width w, the flow velocity distribution in the wider portion is increased compared to the narrower portion, allowing the airflow to act more strongly in a specific direction. When the slit is formed in the peripheral wall of the cylindrical tower section 4A, the angle θ around the central axis (if the tower section is not cylindrical, the angle around the axis centered on the centroid) is preferably 15 to 180 degrees, and more preferably 90 to 180 degrees (see Figure 7). At least one first opening 7A having the above configuration is formed in the peripheral wall of the tower section 4A. In the illustrated embodiment, two first openings 7A, 7A are formed at a position h × (1 / 4) from the base plate. The openings have a slit-like shape with a slit width w gradually narrowing from 3 mm to 1 mm, and the slit length is 80 degrees at an angle θ around the central axis of the tower section 4A. The sides with the wider slit width w of each opening are adjacent to each other on the right peripheral wall of the cylindrical tower section 4A, and the directions α and β of the opening centers [θ × (1 / 2)] of each opening are offset by 100 degrees (see Figures 4 and 7). By dividing the openings into multiple sections in this way, strength is maintained even when the angle θ around the central axis is wide, making the chimney less likely to deform. Furthermore, the first openings 7A are formed in the peripheral wall of the cylindrical tower section 4A, with the upper, lower, left, and right ends between the double walls blocked by walls in a passage-like manner (see Figures 6 and 7). By forming the openings with passages in this way, the airflow emitted from the openings can be made sharp and stable.

[0024] The second opening 7B is formed at a position more than h×(½) from the substrate, and preferably at a position more than h×(⅔) (see FIG. 4). The second opening 7B is formed at a position 5 mm or more above the first opening 7A, and preferably at a position 10 mm or more above. The second opening 7B may have any shape as long as it is formed at a height and in a direction that does not interfere with the airflow discharged from the first opening 7A. One example is a long, thin slit shape parallel to the substrate 2. At least one second opening 7B of the above configuration is formed in a direction different from the opening direction of the first opening 7A (a direction in which the center lines of the angular ranges of each slit-shaped opening 7A, 7B around the central axis of the tower section 4A do not face in the same direction), most preferably in opposite directions, and so that their angular ranges do not overlap each other. In the illustrated embodiment, two second openings 7B, 7B are located at the h × (3 / 4) position of the tower section 4A, above the first opening 7A. The second openings 7B have a slit-like shape with a slit width w that gradually narrows from 3 mm to 1 mm and a slit length of 80 degrees at an angle θ around the central axis of the tower section 4A. The second openings 7B are located on the left side of the peripheral wall opposite the two first openings 7A, 7A, with the wider slit widths of the second openings 7B adjacent to each other and with the directions α and β of their opening centers [θ × (1 / 2)] offset by 100 degrees, so that they are opposite the first opening 7A and do not overlap each other (see Figures 4 and 8). The second opening 7B is also located in the peripheral wall of the cylindrical tower section 4A, which is double-walled, and the upper, lower, left, and right ends between the double walls are blocked by walls, forming a passageway (see Figures 6 and 8).

[0025] The upper opening of the tower section 4A, in which the first opening 7A and the second opening 7B are formed, is closed by the roof section 4B. From the viewpoint of preventing the accumulation of the processed material, the roof section 4B is preferably formed in a conical shape with an upper surface having an apex angle of 90 to 140 degrees. In the illustrated embodiment, the roof section 4B is formed in a hollow structure with a closed space 8 inside the conical shape with an upper surface having an apex angle of 110 degrees (see FIGS. 5 and 6).

[0026] Chimneys 4 each consisting of the tower section 4A and roof section 4B are placed in the small holes 3 formed in the base plate 2, thereby forming a distribution plate 1 having a chimney deck. In this case, the first opening 7A provided in the chimney 4 is arranged facing the direction of the discharge section so that the airflow ejected from the opening 7A is used to move the treated material to the discharge section of the reactor at the end of operation.

[0027] According to the dispersion plate 1 of the present invention described above, the insulating material 2B is disposed on the substrate 2, making it difficult for the materials to be treated to fuse together, even when a high-temperature airflow is used. In particular, when the chimney 4 has a hollow structure (double-wall structure) with an internal closed space 8, as in the embodiment, the insulation is further improved, resulting in a dispersion plate that is difficult for the materials to fuse together. Furthermore, the first opening 7A and the second opening 7B formed in the chimney 4 are formed with different heights and directions, so the vectors of the airflow supplied from each opening contribute to the formation of a fluidized layer without canceling each other out. Furthermore, the airflow from the opening closer to the substrate 2 (the first opening 7A with the lower height) provides a discharge function at the end of operation and makes it difficult for phenomena such as air sliding to occur during operation. Therefore, a stable fluidized layer can be maintained regardless of the layer thickness, improving drying efficiency and work efficiency. In contrast, the perforated plate of Patent Document 2, cited above as background art, uses a pair of airflows in opposite directions, which can suppress the air slide phenomenon to some extent, but does not provide sufficient discharge of powder from the bed at the end of operation. If one of the openings is further widened to achieve sufficient discharge, the air slide phenomenon occurs. Therefore, this does not provide a solution to the problem of both forming a stable fluidized bed and providing good dischargeability at the end of operation.

[0028] The above-described dispersion plate 1 according to the present invention can be used in a dryer, which is a type of reactor, to provide a fluidized bed dryer with good drying efficiency and work efficiency. Fig. 9 is a side view conceptually showing one embodiment of a fluidized bed dryer using the above-described dispersion plate 1 according to the present invention. The illustrated fluidized bed dryer 10 has a drying vessel 11, a powder / granular material inlet 12, a powder / granular material outlet 13, a fluidizing airflow supply section 14, and an outlet 15.

[0029] The drying vessel 11 has a hollow box shape and is formed with a powder or granular material inlet 12 at one end and a powder or granular material outlet 13 at the bottom of the other end. In this case, the powder or granular material inlet 12 and the powder or granular material outlet 13 may be provided one at each end of the drying vessel 11, or a plurality of either one or both may be provided. Wet powder or granular material is continuously supplied into the drying vessel 11 through the powder or granular material inlet 12 by a feeder (not shown). The dried powder or granular material is discharged from the drying vessel 11 through the powder or granular material outlet 13 into a collection hopper (not shown) or the like.

[0030] The interior of the drying container 11 is divided into an upper drying chamber 16 and a lower hot air chamber 17 by installing the above-described dispersion plate 1 according to the present invention at a predetermined distance from the bottom. The first opening 7A provided in the dispersion plate 1 is positioned so that the center of the first opening 7A faces the treated powder / granular material outlet 13 formed in the drying container 11, so that the airflow emitted from the opening 7A is used to move the treated powder / granular material toward the discharge section of the device at the end of operation. The drying container 11 has a hot air chamber 17 defined in the lower part connected to a fluidizing airflow supply section 14, and an outlet 15 for discharging the fluidizing airflow and generated gas formed in the ceiling of the drying chamber 16 defined in the upper part. The fluidizing airflow supply section 14 can be composed of a blower 18 and a heater 19. The outlet 15 is connected to an exhaust fan 21 via a cyclone 20.

[0031] The drying chamber 16 of the drying vessel 11 is divided into a plurality of chambers (four chambers in the illustrated embodiment) in the flow direction of the powder or granular material to be treated by a plurality of (three in the illustrated embodiment) partition plates 22. The partition plates 22a, 22b, 22c are arranged in a vertical direction perpendicular to the flow direction of the powder or granular material to be treated and are arranged at predetermined intervals in the flow direction of the powder or granular material to be treated, with their left and right ends attached to the inner wall surface of the drying vessel 11 and their lower ends positioned with a predetermined gap between them and the dispersion plate 1, and openings 23a, 23b, 23c for the powder or granular material to be treated are secured between the partition plates 22a, 22b, 22c and the dispersion plate 1, respectively.

[0032] As described above, the drying container 11 is partitioned into the first drying chamber 16a, the second drying chamber 16b, the third drying chamber 16c, and the fourth drying chamber 16d by the partition plates 22a, 22b, and 22c. In this case, the first drying chamber 16a is a region where the initial drying of the powder or granular material is performed (preheating drying region). The second and third drying chambers 16b and 16c are regions where the intermediate drying of the powder or granular material is performed (constant rate drying region). And the fourth drying chamber 16d is a region where the final drying of the powder or granular material is performed (falling rate drying region).

[0033] In the fluidized bed dryer 10, powder or granular material is supplied through the powder or granular material inlet 12 to be treated, and a fluidizing airflow is supplied from the fluidizing airflow supply section 14 through the hot air chamber 17 and the dispersion plate 1 to the drying chamber 16, thereby forming a fluidized bed of a predetermined thickness above the dispersion plate 1. The powder or granular material supplied through the powder or granular material inlet 12 is fluidized by the airflows ejected from the first opening 7A and the second opening 7B formed in the dispersion plate 1, thereby efficiently bringing the powder or granular material into contact with the hot air and efficiently transferring the evaporated material. The powder or granular material is then efficiently dried as it moves through the first drying chamber 16a, the second drying chamber 16b, the third drying chamber 16c, and the fourth drying chamber 16d, and is then discharged from the powder or granular material outlet 13. In this case, because the first opening 7A and the second opening 7B formed in the chimney 4 are formed at different heights and directions, the vectors of the airflow supplied from each opening contribute to the formation of a fluidized layer without canceling each other out, and the airflow from the opening closer to the substrate 2 (the first opening 7A with the lower height) provides a discharge function at the end of operation and makes it difficult for phenomena such as air sliding to occur during operation. Therefore, a stable fluidized layer can be maintained regardless of the layer thickness, enabling improved drying efficiency and work efficiency.

[0034] The above describes embodiments of the dispersion plate and fluidized bed dryer that form a fluidized bed according to the present invention. However, the present invention is not limited to the above-described embodiments, and it is natural that various modifications and changes can be made within the scope of the technical concept of the present invention described in the claims. [Industrial Applicability]

[0035] The fluidized bed forming dispersion plate according to the present invention can be widely used to form a fluidized bed in a reactor such as a dryer or an incinerator. [Explanation of symbols]

[0036] 1: dispersion plate, 2: base plate, 2A: sheet plate, 2B: heat insulating material, 3: small hole, 4: chimney, 4A: tower section, 4B: roof section, 5: male screw, 6: lock nut, 7: opening, 7A: first opening, 7B: second opening, 8: closed space, 10: fluidized bed dryer, 11: drying vessel, 12: treated powder / granular material inlet, 13: treated powder / granular material outlet, 14: fluidized air flow supply section, 15: outlet, 16: drying chamber, 16a to 16d: first to fourth drying chambers, 17: hot air chamber, 18: blower, 19: heater, 20: cyclone, 21: exhaust fan, 22, 22a to 22c: partition plate, 23a to 23c: passage opening

Claims

1. A dispersion plate used to form a fluidized bed of powder or granular material in a container having a powder or granular material inlet at one end and a powder or granular material outlet at the bottom of the other end, The dispersion plate includes a substrate, a plurality of small holes provided in the substrate, and a chimney deck in which a chimney is disposed in each of the small holes, The chimney has a first opening having an opening center facing the direction of the powder / granular material discharge port, and a second opening at a height position higher than the first opening and having an opening center facing in a direction opposite to the opening direction of the first opening. A dispersion plate that forms a fluidized layer.

2. The chimney is a dispersion plate that forms a fluidized bed as described in claim 1, characterized in that it consists of a cylindrical tower section and a roof section that covers the upper end opening of the tower section, and the first opening and second opening are formed on the peripheral wall of the tower section.

3. A dispersion plate for forming a fluidized layer as described in claim 1, characterized in that the first opening and the second opening are each formed in the shape of a slit parallel to the substrate.

4. A dispersion plate for forming a fluidized layer as described in claim 1, characterized in that the first opening and the second opening are each formed by two slit-shaped openings whose width gradually narrows, with the sides with the wider slit width adjacent to each other.

5. A dispersion plate for forming a fluidized layer as described in claim 1, characterized in that the second opening is formed at a position that is 5 mm or more higher than the height position of the first opening.

6. A dispersion plate for forming a fluidized bed as described in claim 2, characterized in that the first opening is formed in the shape of a slit having a slit width of 1 to 5 mm and a slit length of 15 to 180 degrees in angle around the central axis of the cylindrical tower section.

7. A dispersion plate for forming the fluidized layer described in claim 1, characterized in that the chimney deck is formed evenly and without bias on the substrate in a staggered or parallel arrangement.

8. A fluidized bed dryer using the dispersion plate for forming a fluidized bed according to any one of claims 1 to 7.

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