Rotary classifier and fluidized bed combustion system

Abstract

To provide a fluid bed combustion system which has a high mixing / stirring function and further improves classification performance.SOLUTION: A rotary classifier according to one aspect includes: a rotary shaft extending along a horizontal direction; a cylindrical screen configured to rotate around a center line of the rotary shaft and transport a fluid medium; and an internal stirring plate supported at the rotary shaft side or the screen side. The internal stirring plate includes a second strip plate connected to a first strip plate. On a cross section orthogonal to the center line of the rotary shaft, the first strip plate extends along a radial direction of the screen and the second strip plate extends along a direction orthogonal to the radial direction of the screen. An inner first long side, located at the inner side in the radial direction of the screen, of a pair of first long sides is connected to the second strip plate or an upstream side second long side, located at the upstream side in a rotation direction, of a pair of second long sides is connected to the first strip plate.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present disclosure relates to a rotary classifier that classifies fluidized sand contained in a fluidizing medium extracted from the furnace bottom of a fluidized bed combustion apparatus and foreign matter contained in the fluidized sand, and a fluidized bed combustion system equipped with the rotary classifier. [Background technology]

[0002] Fluidized bed combustion systems (fluidized bed combustors) are known, in which air is supplied to a fluidized medium (e.g., fluidized sand) to fluidize the medium and combust the fuel mixed in the fluidized medium. When a fluidized bed combustor is applied to an incinerator that incinerates municipal solid waste (MSW), a screw conveyor is provided to remove the non-combustible material (foreign matter) from the bottom of the furnace in order to separate non-combustible material (foreign matter) contained in the municipal solid waste from the fluidized sand. A cylindrical rotary sieve (rotary classifier) ​​is provided downstream of the screw conveyor in the transport direction, and the rotary sieve separates the fluidized sand from the foreign matter, returning only the fluidized sand to the incinerator.

[0003] The applicant has previously proposed improving the classification performance of fluidized sand and foreign matter by devising the shape of the sieve mesh formed on the rotary sieve and the arrangement of the feed blades fixed to the inner surface of the rotary sieve to send the fluidized medium to the outlet side (Patent Document 1). Patent Document 2 discloses a rotary classifier that mixes, stirs, and classifies soil and sand, and that has a mixing and stirring section equipped with stirring blades on the upstream side in the direction of transport of the soil and sand, and a classification section downstream of the mixing and stirring section that has a cylindrical sieve surface and a device for preventing clogging of the sieve surface. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Publication No. 2021-081118 [Patent Document 2] Japanese Patent Application Laid-Open No. 2009-039646 Summary of the Invention [Problem to be solved by the invention]

[0005] In order to improve the classification performance of a rotary classifier, it is effective to improve the mixing and stirring effect by mixing and stirring the materials to be classified before or during classification, as in the rotary classifier described in Patent Document 2. However, the rotary classifier described in Patent Document 2 has rod-shaped stirring blades, which means that the mixing and stirring effect of the sediment is insufficient, and there is a limit to the classification performance of the sediment.

[0006] The present disclosure has been made in consideration of the above-mentioned circumstances, and aims to provide a rotary classifier applied to a fluidized bed combustion apparatus with a high mixing and stirring function to improve classification performance. [Means for solving the problem]

[0007] In order to achieve the above object, one aspect of the rotary classifier according to the present disclosure is a rotary classifier configured to classify fluidized sand and foreign matter contained in a fluidized medium extracted from a fluidized bed combustion apparatus, the rotary classifier comprising: a rotation axis extending along a horizontal direction; a cylindrical screen configured to rotate around the center line of the rotation axis, the screen configured to transfer the fluidized medium introduced therein to one side in the axial direction; and an internal stirring plate supported on the rotation axis side or the screen side, the internal stirring plate extending along the axial direction of the screen. The screen includes a first band-shaped plate having a pair of first long sides, and a second band-shaped plate having a pair of second long sides extending along the axial direction of the screen, the second band-shaped plate being connected to the first band-shaped plate, wherein in a cross section perpendicular to the center line of the rotation shaft, the first band-shaped plate extends along the radial direction of the screen, and the second band-shaped plate extends along a direction perpendicular to the radial direction of the screen, and an upstream second long side of the pair of second long sides located upstream in the rotation direction is connected to an inner first long side of the pair of first long sides located inside the radial direction of the screen.

[0008] One aspect of a fluidized bed combustion system according to the present disclosure includes a fluidized bed combustion apparatus, a rotary classifier described in any one of 1) to 10), and a transfer device configured to transfer the fluidized medium from the fluidized bed combustion apparatus to the rotary classifier. [Effects of the Invention]

[0009] According to the rotary classifier and fluidized bed combustion system of the present disclosure, the stirring effect of the bed material inside the screen can be improved, thereby promoting the separation action between the fluidized sand and foreign matter, which can suppress the bed material from overshooting toward the foreign matter and improve the classification performance between the bed material and foreign matter. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a schematic configuration diagram of a fluidized bed combustion system according to an embodiment. [Figure 2] 1 is a schematic diagram of a fluidized bed combustion apparatus according to an embodiment. [Figure 3] 1 is a partially cutaway front view of a rotary classifier according to an embodiment. [Figure 4] 4 is a partially cutaway side view (a cross-sectional view taken along line AA in FIG. 3) showing an internal stirring plate of the rotary classifier according to one embodiment. [Figure 5A] 1 is a schematic side view showing an internal stirring plate of a rotary classifier according to one embodiment, illustrating a cross section perpendicular to the central axis of a rotation shaft. FIG. [Figure 5B] 1 is a schematic side view showing an internal stirring plate of a rotary classifier according to one embodiment, illustrating a cross section perpendicular to the central axis of a rotation shaft. FIG. [Figure 5C] 1 is a schematic side view showing an internal stirring plate of a rotary classifier according to one embodiment, illustrating a cross section perpendicular to the central axis of a rotation shaft. FIG. [Figure 6] 1 is a partially cutaway front view of a rotary classifier according to an embodiment. [Figure 7] 7 is a partially cutaway side view (a cross-sectional view taken along line BB in FIG. 6) of a rotary classifier according to one embodiment. [Figure 8]1 is a table showing experimental results of examples and comparative examples of a rotary classifier according to an embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, several embodiments of the present invention will be described with reference to the accompanying drawings. However, the dimensions, materials, shapes, relative arrangements, etc. of the components described in these embodiments or shown in the drawings are merely illustrative examples and are not intended to limit the scope of the present invention. For example, expressions expressing relative or absolute arrangement such as "in a certain direction," "along a certain direction," "parallel," "orthogonal," "center," "concentric," or "coaxial" not only express such an arrangement exactly, but also express a state in which there is a relative displacement with a tolerance or an angle or distance to the extent that the same function is obtained. For example, expressions such as "identical," "equal," and "homogeneous" that indicate that something is in an equal state not only indicate a state of strict equality, but also indicate a state in which there is a tolerance or a difference to the extent that the same function is obtained. For example, expressions representing shapes such as a square shape or a cylindrical shape not only represent shapes such as a square shape or a cylindrical shape in the strict geometric sense, but also represent shapes including uneven portions, chamfered portions, etc., to the extent that the same effect can be obtained. On the other hand, the expressions "comprises," "includes," "has," "includes," or "has" one element are not exclusive expressions that exclude the presence of other elements.

[0012] (Fluidized Bed Combustion System) Fig. 1 is a schematic diagram of a fluidized bed combustion system according to one embodiment. Fig. 2 is a schematic diagram of a fluidized bed combustion apparatus according to one embodiment. As shown in Fig. 1, the fluidized bed combustion system 1 according to one embodiment includes a fluidized bed combustion apparatus 2, a transfer device 3, and a rotary classifier 4.

[0013] (Fluidized bed combustion equipment) As shown in Fig. 2, the fluidized bed combustor 2 includes a furnace 21 having an internal combustion chamber 210. The furnace 21 fluidizes a fluidized medium FM stored in the combustion chamber 210 to form a fluidized bed 211, and burns a fuel FU introduced into the fluidized bed 211. The fluidized medium FM contains fluidized sand S (for example, particles mainly composed of SiO2, such as silica sand) which is fine granules having a high melting point equal to or higher than the combustion gas temperature in the furnace 21.

[0014] The furnace 21 is formed in a cylindrical shape extending along the vertical direction, and includes a side wall 22, a ceiling portion 23 covering the upper end of the side wall 22, and a furnace bottom portion 24 covering the lower end of the side wall 22. In the combustion chamber 210, a storage portion 212 is formed on the bottom surface of the furnace bottom portion 24, in which the bed material FM is stored. 2, the furnace bottom 24 is formed with a plurality of primary air supply ports 242 and a furnace bottom discharge port 243 located in the center, which communicate with the reservoir 212. The side wall 22 is provided with a secondary air introduction line 13, an exhaust gas discharge line 15, a downstream fluidizing sand supply line 16A, and a fuel introduction line 14, which all communicate with the space above the combustion chamber 210. The furnace further includes a primary air introduction line 12 that sends primary air (fluidizing air) A1 to the reservoir 212 via the plurality of primary air supply ports 242.

[0015] Secondary air (combustion air) A2 is supplied from a secondary air inlet line 13, and the fuel FU is sent from a fuel storage device 11 (e.g., a hopper, see FIG. 1) that is provided outside the furnace 21 and configured to store the fuel FU to the storage section 212 from a fuel inlet line 14. The bed material FM stored on the bottom surface of the furnace bottom 24 is fluidized by the primary air A1 sent from a primary air supply port 242, and forms the above-mentioned fluidized bed 211 in the lower part of the combustion chamber 210.

[0016] The fuel FU sent to the storage section 212 is combusted in the fluidized bed 211 where the bed material FM is fluidized. Unburned fuel and pyrolysis gas in the exhaust gas generated by this combustion are combusted by secondary air A2 in the space above the combustion chamber 210. The exhaust gas E generated by the combustion is discharged to the outside of the furnace 21 through the exhaust gas discharge line 15.

[0017] In the illustrated embodiment, as shown in Fig. 2, the fluidized bed combustor 2 includes a furnace 21 and a heat exchanger 25 configured to recover thermal energy generated by combustion in the furnace 21, and constitutes a fluidized bed boiler. The thermal energy recovered by the heat exchanger 25 is used for power generation, etc. Note that in other embodiments, the fluidized bed combustor 2 may have a configuration other than that of a fluidized bed boiler (a configuration that does not include the heat exchanger 25).

[0018] In the embodiment illustrated in FIG. 2, the heat exchange device 25 includes a heat transfer tube 252 provided in the flue 251 , and the heat transfer tube 252 recovers thermal energy from the flue gas flowing through the flue 251 . In other embodiments, the heat exchanger 25 may include a heat transfer tube provided in the fluidized bed 211 to recover thermal energy from the fluidized sand S, or a furnace wall tube that forms the side wall 22 of the furnace 21 and recovers thermal energy from the exhaust gas and pyrolysis gas in the combustion chamber 210.

[0019] The fluidized bed combustor 2 described above is capable of burning a variety of fuels (e.g., bituminous coal, lignite, petroleum coke, woody biomass, paper sludge, refuse-derived fuel (RDF), waste tires, etc.) and has high combustion efficiency. The various fuels described above may contain foreign matter F. For example, when woody biomass such as wood chips or construction waste is used as fuel, nails, metal objects, gravel, etc. may be contained as foreign matter. For this reason, as shown in FIG. 2 , the fuel FU sent to the storage unit 212 via the fuel introduction line 14 and the bed material FM stored in the storage unit 212 may contain foreign matter F in addition to fluidizing sand S.

[0020] If the proportion of foreign matter F contained in the fluidized medium FM stored in the storage section 212 increases, this may result in a decrease in combustion efficiency in the fluidized bed 211 or damage to the heat transfer tubes installed in the fluidized bed 211.Therefore, the fluidized medium FM is extracted from the storage section 212, the foreign matter F is removed from the extracted fluidized medium FM, and then the fluidized medium FM is returned to the storage section 212.

[0021] 1, the fluidized bed combustion system 1 extracts the fluidized medium FM (including fluid sand S and foreign matter F) stored in the storage section 212 of the furnace 21 to the outside of the furnace 21, and after the foreign matter is removed from the extracted fluidized medium FM using the rotary classifier 4, the fluidized medium FM is returned to the inside of the furnace 21 through the fluidized sand supply line 16. The outside of the furnace 21 further includes a fluidized sand introduction line 17 configured to send fluidized sand from a fluidized sand storage device 171 (e.g., a hopper) that stores fluidized sand S to the storage section 212 of the furnace 21.

[0022] The transfer device 3 described above is provided between the fluidized bed combustor 2 and the rotary classifier 4, and is configured to transfer the bed material FM extracted from the fluidized bed combustor 2 to the rotary classifier 4. The rotary classifier 4 is configured to classify the bed material FM extracted from the fluidized bed combustor 2 into fluid sand S and foreign matter F.

[0023] 1, the rotary classifier 4 includes a cylindrical screen 5 that classifies the fluidized medium FM supplied thereinto into fluid sand S and foreign matter F, and a casing 41 that houses the screen 5. The casing 41 is formed with a fluid sand discharge port 42 for discharging the fluid sand S classified by the screen 5 to the outside of the casing 41, and a foreign matter discharge port 43 for discharging the foreign matter F classified by the screen 5 to the outside of the casing 41. The fluid sand introduction line 17 merges with the fluid sand supply line 16 at a junction 172 located downstream of the rotary classifier 4 in the flow direction of the fluid sand S of the fluid sand supply line 16.

[0024] The fluid sand supply line 16 includes a pipe 161 connecting the fluid sand discharge outlet 42 and the junction 172, and a valve 164 (e.g., an on-off valve) provided on the pipe 161. The fluid sand S discharged from the fluid sand discharge outlet 42 falls through the pipe 161 and is sent to the junction 172. The fluid sand introduction line 17 includes a pressure pump 173 located upstream of the junction 172 in the flow direction, for pressure-feeding the fluid sand S downstream in the flow direction. The pressure pump 173 is a shared facility that is also used to pressure-feed the fluid sand S located at the junction 172 of the fluid sand supply line 16 and downstream of the junction 172.

[0025] 1, the fluidized bed combustion system 1 further includes a switching device 18 provided in the fluid sand supply line 16, and a fluid sand discharge line 19 branching off from the fluid sand supply line 16 and for withdrawing the fluid sand S from the fluid sand supply line 16. The switching device 18 and the fluid sand discharge line 19 are each provided downstream of the junction 172 in the flow direction of the fluid sand S. The switching device 18 is configured to be able to switch the destination of the fluid sand S to either the fluid sand supply line 16A or the fluid sand discharge line 19, which is downstream of the switching device 18 of the fluid sand supply line 16 in the flow direction of the fluid sand S.

[0026] When the switching device 18 is set as the destination of the fluidized bed combustion system 1 to the downstream fluidized bed supply line 16A, the fluidized bed combustion system 1 is supplied with fluidized bed combustion system S via the downstream fluidized bed supply line 16A.

[0027] In addition, in the embodiment illustrated in FIG. 1, the fluidized bed combustion system 1 includes a bag filter 162 provided in the fluidized sand supply line 16, and the bag filter 162 is provided between the confluence 172 and the switching device 18 and collects the fluidized sand S passing through the bag filter 162.

[0028] (transfer device) As described above, the transfer device 3 is provided between the fluidized bed combustor 2 and the rotary classifier 4, and is configured to transfer the bed material FM extracted from the fluidized bed combustor 2 to the rotary classifier 4. In the embodiment shown in Fig. 1, the transfer device 3 includes a screw conveyor 3A. Note that in other embodiments, the transfer device 3 may be something other than the screw conveyor 3A.

[0029] The screw conveyor 3A includes at least one screw shaft 31 and a conveyor casing 32 that houses the screw shaft 31. The screw shaft 31 includes a rotating shaft 33 that extends along a central axis CS that is aligned in the horizontal direction, and screw blades 34 that are provided on the outer periphery of the rotating shaft 33 and protrude in a spiral shape.

[0030] The screw conveyor 3A further includes a drive source device 35 that rotates the screw shaft 31 about the central axis CS as the center of rotation, and a rotational force transmission member 36 that is connected to the drive source device 35 and the screw shaft 31 and transmits rotational force from the drive source device 35 to the screw shaft 31. The drive source device 35 may be, for example, a motor, and the rotational force transmission member 36 may be, for example, a coupling.

[0031] The screw conveyor 3A is configured to rotate the screw shaft 31 to capture bed material FM (including fluid sand S and foreign matter F) in the gaps between the pitches of the screw blades 34, and to transport the captured bed material FM to one side (the right side in Figure 1) in the direction in which the central axis CS extends.

[0032] The conveyor casing 32 defines an internal space 320 that accommodates the screw shaft 31. The conveyor casing 32 is formed with a bed material inlet 321 for introducing the bed material FM into the internal space 320, and a bed material outlet 322 for discharging the bed material FM transferred to the screw shaft 31 from the internal space 320 to the outside. The bed material inlet 321 is formed on the other side (left side in FIG. 1) of the conveyor casing 32 in the direction in which the central axis CS extends. The bed material outlet 322 is formed at an end 324 (see FIG. 3) of the conveyor casing 32 on the one side in the direction in which the central axis CS extends.

[0033] 1 includes a pipe 163 that connects the furnace bottom discharge port 243 of the furnace 21 and the bed material inlet 321 of the conveyor casing 32. The pipe 163 extends vertically, and the bed material stored in the storage section 212 of the furnace 21 falls through the pipe 163 and is sent to the internal space 320 of the conveyor casing 32.

[0034] 3, the one end 324 of the conveyor casing 32 is inserted into the cylindrical screen 5 of the rotary classifier 4. The bed material FM sent to the internal space 320 of the conveyor casing 32 is transported by the screw shaft 31 within the internal space 320 to the downstream side in the transport direction (the direction of arrow b in FIG. 3), and is supplied into the inside of the screen 5 from the bed material discharge port 322.

[0035] (Rotary classifier) As described above, the rotary classifier 4 is configured to classify the fluidized sand S and the foreign matter F contained in the fluidized medium FM extracted from the fluidized bed combustor 2. As shown in FIG. 1, the rotary classifier 4 includes the above-mentioned cylindrical screen 5 and a casing 41 in which the above-mentioned fluidized sand discharge port 42 and foreign matter discharge port 43 are formed.

[0036] Figures 3 and 4 are a front view and a side view, with parts cut away, showing one embodiment of a rotary classifier according to the present disclosure. Figures 5A to 5C are side schematic views showing several other embodiments. Figures 4 and 5A to 5C show cross sections perpendicular to the central axis CA of the rotary shaft 44.

[0037] The rotary classifier 4 shown in Figures 3, 4, and 5A to 5C includes a rotary shaft 44 extending horizontally at its center, and a cylindrical screen 5 configured to rotate about a central axis CA of the rotary shaft 44. The rotary shaft 44 and the screen 5 rotate in the direction of arrow a shown in Figure 4. The screen 5 transfers the bed material FM introduced therein toward one axial side (the right side in Figure 3) along the central axis CA, and transfers the bed material FM (particularly foreign matter F) from the other axial side (the left side in Figure 3) in the axial direction.

[0038] In these embodiments, the screen 5 is provided with an internal stirring plate 45 supported on the rotary shaft 44 side or the screen 5 side inside. The internal stirring plate 45 includes a first band-shaped plate 451 and a second band-shaped plate 452 as its constituent members. The first band-shaped plate 451 has a pair of first long sides 451a and 451b extending along the axial direction of the screen 5. The second band-shaped plate 452 has a pair of second long sides 452a and 452b extending along the axial direction of the screen 5. The first band-shaped plate 451 and the second band-shaped plate 452 are connected to each other, and in a cross section perpendicular to the central axis CA (a cross section in the direction shown in FIGS. 4 and 5A to 5C), the first band-shaped plate 451 extends along the radial direction of the screen 5, and the second band-shaped plate 452 extends along a direction perpendicular to the radial direction of the screen 5.

[0039] In the rotary classifier 4 (4A) according to the embodiment shown in Figure 4, the internal stirring plate 45 (45a) has an upstream second long side 452a, which is located upstream in the direction of rotation a, of the pair of second long sides 452a and 452b of the second strip plate 452, connected to an inner first long side 451a, which is located radially inward of the screen 5, of the pair of first long sides 451a and 451b of the first strip plate 451. In FIG. 4, a dashed dotted line L1 is a straight line extending in the radial direction of the screen 5, and a dashed dotted line L2 is a straight line perpendicular to the dashed dotted line L1.

[0040] In the rotary classifier 4 (4B) according to the embodiment shown in FIG. 5A, the internal stirring plate 45 (45b) is fixed to the inner surface of the screen 5, and thus the configuration is different from the internal stirring plate 45 (45a) of the rotary classifier 4 (4A). On the other hand, the other configurations are the same as the internal stirring plate 45 (45a). For example, in the internal stirring plate 45 (45b), similar to the internal stirring plate 45 (45a) shown in FIG. 4, the upstream second long side 452a, which is located upstream in the direction of rotation a, of a pair of second long sides 452a and 452b of the second band-shaped plate 452, is connected to the inner first long side 451a, which is located radially inward of the screen 5, of a pair of first long sides 451a and 451b of the first band-shaped plate 451.

[0041] Figures 5B and 5C each show another embodiment. In the rotary classifier 4 (4B') according to the embodiment shown in Figure 5B, the internal stirring plate 45 (45b') is fixed to the inner surface of the screen 5, similar to the internal stirring plate 45 (45b) of the rotary classifier 4 (4B) shown in Figure 5A. However, the inner first long side 451a, which is located radially inward of the screen 5, of the pair of first long sides 451a and 451b of the first band-shaped plate 451, is connected to the second band-shaped plate 452, and the inner first long side 451a is not connected to the upstream second long side 452a of the second band-shaped plate 452, in that it has a different configuration from the internal stirring plate 45 (45b).

[0042] Furthermore, in the rotary classifier 4 (4B") according to the embodiment shown in Figure 5C, the internal stirring plate 45 (45b") is fixed to the inner surface of the screen 5, similar to the internal stirring plate 45 (45b) shown in Figure 5A. However, the configuration differs from the internal stirring plate 45 (45b) shown in Figure 5A in that the upstream second long side 452a, which is located upstream in the direction of rotation of the pair of second long sides 452a and 452b of the second band-shaped plate 452, is connected to the first band-shaped plate 451 and is not connected to the inner first long side 451a of the first band-shaped plate 451. In addition, in Figs. 5A and 5B, in the case of an embodiment in which the internal stirring plate 45 (45b', 45b") is supported on the rotary shaft 44 side, it is attached to and supported by a support member supported by a two-dot chain line.

[0043] In each embodiment shown in FIGS. 3, 4, and 5A to 5C, bed material FM (fluid sand S and foreign matter F) is introduced into the screen 5 from a bed material discharge port 322 provided at one end 324 of the conveyor casing 32. When the internal stirring plate 45 rotates in direction a together with the rotary shaft 44, the bed material FM that has accumulated in the lower part of the screen 5 is scooped up by the first band-shaped plate 451 and lifted to an upper space within the screen 5 while remaining stored in a storage space Ss formed between the first band-shaped plate 451 and the second band-shaped plate 452. In the upper space, the bed material FM is held in the upper space by the second band-shaped plate 452 and then slides down from the second band-shaped plate 452. That is, the first belt-shaped plate 451 has the function of scooping up the bed material FM accumulated in the lower part of the screen 5 and lifting it up toward the upper space within the screen 5, and the second belt-shaped plate 452 has the function of holding the bed material FM in the upper space for a certain period of time and causing the bed material FM to fall in the downstream region of the upper space. Since this operation is repeated every time the internal stirring plate 45 rotates once, the bed material FM is efficiently stirred inside the screen 5.

[0044] As the screen 5 rotates in the direction of arrow a, the feed mechanism of the screen 5 transports the bed material FM toward the foreign matter discharge port 43. At the same time, the stirring action of the internal stirring plate 45 separates the fluid sand S from the foreign matter F. The sieve surface formed on the outer periphery of the screen 5 has sieve openings larger than the fluid sand S but smaller than the foreign matter F. Therefore, the fluid sand S of the stirred bed material FM passes through the sieve surface of the screen 5 and is discharged to the fluid matter discharge port 42. Meanwhile, the foreign matter F has a larger diameter than the sieve openings of the screen 5, so it is sent by the feeding action of the screen 5 toward the foreign matter discharge port 43 and discharged from the foreign matter discharge port 43. In this way, the stirring effect of the internal stirring plate 45 can be improved, thereby improving the classification performance of the fluid sand S and the foreign matter F. In particular, overshooting of the fluid sand S toward the foreign matter discharge port 43 can be suppressed.

[0045] 4, a feed blade 51 is provided on the inner surface of the screen 5. The feed blade 51 is composed of a plurality of strips arranged so as to be inclined with respect to the axial and circumferential directions of the screen 5, and the long sides of the strips are fixed to the screen 5. When the screen 5 rotates, the feed blades 51 push the bed material FM toward the foreign matter discharge port 43.

[0046] In another embodiment, the screen 5 is arranged so as to incline downward toward one side (the foreign matter discharge port 43 side; the right side of the paper in FIG. 3). As a result, gravity acts toward the outlet side on the bed material FM accumulated inside the screen 5, and as the screen 5 rotates, the bed material FM gradually moves toward the outlet side. This feeding mechanism may be combined with a feeding mechanism using a feeding blade 51.

[0047] 3, the rotary shaft 44 is integrally connected to the rotary shaft 33 of the screw conveyor 3A, and the rotary shaft 44 is disposed so that the central axis CS of the screw conveyor 3A and the central axis CA of the rotary shaft 44 form a straight line. This allows the drive source device 35 of the screw conveyor 3A to also serve as the rotation drive device for the rotary shaft 44.

[0048] 3, one end (the right side in FIG. 3) of the rotating shaft 44 in the direction in which the central axis CA extends is rotatably supported by a bearing 46. A packing 461 is incorporated inside the bearing 46, and the one end of the rotating shaft 44 is rotatably supported via the packing 461.

[0049] In one embodiment, as in the internal stirring plate 45 (45a) of the rotary classifier 4 (4A) shown in Figures 3 and 4 and the internal stirring plate 45 (45b) of the rotary classifier 4 (4B) shown in Figure 5A, the upstream second long side 452a, which is located upstream in the rotation direction a, of the pair of second long sides 452a and 452b of the second strip plate 452 is connected to the inner first long side 451a, which is located radially inward of the screen 5, of the pair of first long sides 451a and 451b of the first strip plate 451. According to this embodiment, the upstream second long side 452a of the second band-shaped plate 452 is connected to the inner first long side 451a of the first band-shaped plate 451, so that the storage space Ss formed between the first band-shaped plate 451 and the second band-shaped plate 452 can be enlarged. This increases the amount of bed material FM that can be lifted into the space above the screen 5. This further improves the agitation effect of the bed material FM, contributing to improved classification performance for separating the fluid sand S from the foreign matter F.

[0050] 4, the first band-shaped plate 451 extends in the same direction as the straight line L1, and the second band-shaped plate 452 extends in the same direction as the straight line L2. That is, the angle between the first band-shaped plate 451 and the second band-shaped plate 452 is 90°, which allows the volume of the storage space Ss to be further increased.

[0051] In each embodiment shown in FIGS. 5A to 5C, the internal stirring plate 45 (45b, 45b', 45b'') is fixed to the inner surface of the screen 5 and rotates together with the screen 5. In this embodiment, classification performance similar to that of the internal stirring plate 45 (45a) shown in FIGS. 3 and 4 can be achieved, and since the internal stirring plate 45 (45b, 45b', 45b'') is fixed to the inner surface of the screen 5, the support mechanism for the internal stirring plate 45 can be made more compact than that of the internal stirring plate 45 (45a).

[0052] 5A to 5C, the outer first long side 451b of the pair of first long sides 451a and 451b of the first belt-shaped plate 451 is joined to the inner surface of the screen 5. The outer first long side 451b is arranged along the axial direction of the screen 5.

[0053] 5A, in a cross section perpendicular to the central axis CA of the rotation shaft 44, the angle θ1 formed between the first band-shaped plate 451 and the radial direction of the screen 5 is in the range of -10°≦θ1≦45°, with the downstream side of the rotation direction a being positive. In the figure, a dashed-dotted line L1 is a straight line that passes through the central axis CA of the screen 5 and is disposed in the radial direction of the screen 5. The angle θ2 formed between the second band-shaped plate 452 and a direction perpendicular to the radial direction of the screen 5 (the direction of the line L1) is in the range of -45°≦θ2≦20°, with the downward side being positive. In the figure, the dashed-dotted line L2 is a straight line that is disposed in the direction perpendicular to the radial direction of the screen 5 (the direction of the line L1). The angle θ formed between the first band-shaped plate 451 and the second band-shaped plate 452 is configured to be in the range of 60°≦θ≦120°.

[0054] According to this embodiment, the angle θ1 formed by the first band plate 451 and the radial direction of the screen 5 is in the range of -10°≦θ1≦45°, with the downstream side of the rotation direction a being positive, so that the first band plate 451 can have the function of scooping up the bed material FM accumulated in the lower part of the screen 5 and lifting it up toward the upper space within the screen 5. Preferably, the angle θ1 is in the range of 10°≦θ1≦45°, which can further improve the scooping action of the bed material FM. In addition, the second band plate 452 can have the function of holding the bed material FM in the upper space for a certain period of time and dropping the bed material FM in the downstream region of the upper space. Furthermore, the angle θ2 formed by the second belt-shaped plate 452 and the direction perpendicular to the radial direction of the screen 5 (the direction of the straight line L1) is in the range of -45°≦θ2≦20°, with the downward side being positive, so that the bed material FM can be held for a certain period of time in the top space St within the screen 5 and allowed to fall in the downstream region of the top space St. Normally, the angle of repose of the bed material FM is 20° to 40°, but since the angle of repose of the second belt-shaped plate 452 is in the range of θ2≦20°, the bed material FM can be held for a certain period of time in the top space St in accordance with the angle of repose of the bed material (FM), and the bed material FM can be prevented from falling during this period. Furthermore, since the angle θ between the first band-shaped plate 451 and the second band-shaped plate 452 is within the range of 60°≦θ≦120° (preferably, 80°≦θ≦100°), the storage space Ss formed between the first band-shaped plate 451 and the second band-shaped plate 452 can have a volume large enough to store a sufficient amount of bedded medium FM. Therefore, the effect of stirring the bedded medium FM by the internal stirring plate 45 can be further improved.

[0055] 3 and 4, the internal agitator 45 includes a shielding plate 453 disposed on the other axial side (left side in FIG. 3) of the screen 5 of the first band-shaped plate 451 and the second band-shaped plate 452, straddling the other end portions of the first band-shaped plate 451 and the second band-shaped plate 452, so as to separate the storage space Ss. The shielding plate 453 prevents the bed material FM scooped up by the internal agitator 45 and stored in the storage space Ss from falling from the end portions of the first band-shaped plate 451 and the second band-shaped plate 452 on the upstream side in the transfer direction of the bed material FM. This allows the bed material FM to be smoothly fed toward the foreign matter discharge port 43.

[0056] 3 and 4, rotating shaft 44 includes a shaft main body 441 and a protector 442 formed of a cylindrical body surrounding shaft main body 441. Protector 442 is disposed in the axial direction of screen 5 so as to at least partially overlap with the region in which internal stirring plate 45 is disposed. According to this embodiment, protector 442 is provided around shaft main body 441, and therefore shaft main body 441 can be prevented from being worn down by fluid medium FM dropping onto rotating shaft 44 from above.

[0057] In the illustrated embodiment, as shown in Fig. 3, the other end of the protector 442 (left side of the paper in Fig. 3) and the other end of the internal stirring plate 45 are arranged such that the other end of the protector 442 is shifted to one side (right side of the paper in Fig. 3) by a length x in the axial direction of the screen 5. Furthermore, the one end of the protector 442 (right side of the paper in Fig. 3) and the one end of the internal stirring plate 45 are arranged such that the one end of the protector 442 is shifted to one side (right side of the paper in Fig. 3) by a length y in the axial direction of the screen 5. The lengths x and y correspond to the amount of the bed material FM fed to one side while the bed material FM accumulated in the lower part of the screen 5 is lifted up to the top space St by the internal stirring plate 45, i.e., while the internal stirring plate 45 makes a half rotation. By setting the length of the protector 442 in the screen axial direction in this way, the protector 442 can be disposed at a position where the bed material FM actually falls, and therefore wear on the shaft main body 441 can be efficiently prevented.

[0058] In the embodiment shown in FIGS. 3 and 4 , protector 442 is composed of a pair of semi-cylindrical bodies 442a and 442b each having a semicircular cross section perpendicular to the axial direction. Each of the pair of semi-cylindrical bodies 442a and 442b has a bolt fastening plate 442c at its circumferential end, protruding outward from the outer circumferential surface. When the pair of semi-cylindrical bodies 442a and 442b are surrounded by shaft main body 441, the bolt fastening plates 442c are arranged to face each other. By bolting together the bolt fastening plates 442c arranged to face each other, the pair of semi-cylindrical bodies 442a and 442b can be fixed to shaft main body 441. By configuring protector 442 from a pair of semi-cylindrical bodies 442a and 442b in this way, attachment and detachment to and from shaft main body 441 is facilitated.

[0059] 3 and 4, each of the pair of semi-cylindrical bodies 442a and 442b has a reinforcing plate 442d extending in the circumferential direction. The reinforcing plate 442d is provided at a position in the axial direction of the pair of semi-cylindrical bodies 442a and 442b where it can be coupled to the bolt coupling plate 442c, and is disposed so as to protrude outward from the outer circumferential surfaces of the semi-cylindrical bodies 442a and 442b, and is coupled to the bolt coupling plate 442c. By providing the reinforcing plate 442d, the bolt coupling plate 442c can be reinforced.

[0060] In one embodiment, at least one connecting bar 47 is provided, one end of which is supported by the rotation shaft 44 and which extends along the radial direction of the screen 5. The other end of the connecting bar 47 is connected to the internal stirring plate 45, and the internal stirring plate 45 is supported by the rotation shaft 44 via the connecting bar 47. According to this embodiment, the internal stirring plate 45 is supported by the connecting bar 47, which simplifies and reduces the cost of the support mechanism for the internal stirring plate 45. Furthermore, because the internal stirring plate 45 is supported by the connecting bar 47, the weight of the rotated part supported by the rotating shaft 44 can be reduced, which in turn reduces the power of the drive device that rotates the rotating shaft 44.

[0061] 3 and 4, the connecting bar 47 is made up of a bar piece 471 arranged on the internal stirring plate 45 side and a bar piece 472 arranged on the rotating shaft 44 side, and these bar pieces are detachably joined to each other so as to form a straight line to form the connecting bar 47. Because the connecting bar 47 is divided into bar pieces 471 and 472 that are separated in the axial direction, the internal stirring plate 45 can be easily attached and detached to the rotating shaft 44.

[0062] In an embodiment in which a protector 442 is provided around the shaft main body 441, one end of the connecting bar 47 is connected to the protector 442, and in an embodiment in which a protector 442 is not provided, one end of the connecting bar 47 is connected to the shaft main body 441.

[0063] In the embodiment shown in Figure 3, the connecting bar 47 is located at the center of the internal stirring plate 45 in the axial direction of the screen 5, but in another embodiment, two connecting bars 47 may be located at both ends of the internal stirring plate 45.

[0064] 3, in the axial direction of the screen 5, the length of the internal stirring plate 45 is configured to be shorter than the axial length of the screen 5. In addition, the center position of the internal stirring plate 45 is arranged to be located on the other side of the axial center position of the screen 5 in the direction in which the central axis CA of the rotation shaft 44 extends (upstream in the conveying direction of the bed material FM; left side of the paper in FIG. 3).

[0065] According to this embodiment, the internal stirring plate 45 does not extend to the vicinity of the foreign matter discharge outlet 43 in the screen axial direction, so that the stirring action of the internal stirring plate 45 can prevent the fluid sand S from being discharged together with foreign matter F from the foreign matter discharge outlet 43.

[0066] In one embodiment, the rotating shaft 44 and the screen 5 are configured to rotate in the same direction at the same speed. As shown in Fig. 4, the feed blade 51 fixed to the inner peripheral surface of the screen 5 has the function of feeding the bed material FM inside the screen 5 to the outlet side of the screen 5, as described above, and is disposed at a position different from the internal stirring plate 45 in the circumferential direction of the screen.

[0067] According to this embodiment, the rotary shaft 44 and the screen 5 are configured to rotate in the same direction at the same speed, so a single drive unit can be used to rotate both the rotary shaft 44 and the screen 5. This allows these drive units to be made more compact. Furthermore, because the rotary shaft 44 and the screen 5 rotate in the same direction at the same speed, in an embodiment in which the feed blade 51 is provided on the inner circumferential surface of the screen 5, the relative positions of the feed blade 51 and the internal agitator 45, which are located at different positions in the circumferential direction of the screen 5, do not change. Therefore, even if the internal agitator 45 and the feed blade 51 are located at the same axial position of the screen 5, there is no risk of interference between the feed blade 51 and the internal agitator 45 during operation of the rotary classifier 4.

[0068] In the embodiment shown in FIG. 4, a plurality of internal stirring plates 45 are arranged at equal intervals in the circumferential direction of the screen 5, and a plurality of feed blades 51 are arranged between each of the internal stirring plates 45.

[0069] In the embodiment shown in FIGS. 3 and 4 , the screen 5 is supported by a support structure 52. The support structure 52 includes a plurality of frame members 521 that are distributed around the circumferential direction of the screen 5 and extend along the axial direction of the screen 5, an annular frame member 522 to which one end of the frame members 521 (the end on the side of the foreign material discharge port 43 located on the right side in FIG. 3 ) is connected, and a plurality of bars 523 that are distributed around the circumferential direction of the screen 5. The plurality of bars 523 are connected to the rotation shaft 44 and the annular frame member 522 and are arranged radially from the rotation shaft 44 toward the annular frame member 522. The outer peripheral surface of the screen 5 is fixed to the frame member 521. The support structure 52 also includes a plurality of bars 524 that are arranged near the bed material discharge port 322 of the screw conveyor 3A in the axial direction of the screen 5. The plurality of bars 524 are connected to the rotation shaft 44 and the frame member 521 and are arranged radially from the rotation shaft 44 toward the frame member 521.

[0070] In this embodiment, the rotary shaft 44 and the screen 5 are integrally connected via a support structure 52. Therefore, the rotary shaft 44, the internal stirring plate 45, and the screen 5 rotate in the same direction and at the same speed. Also, in the embodiment shown in Figures 3 and 4, the rotary shaft 33 and the rotary shaft 44 of the screw conveyor 3A are integrally connected, so the screw blades 34, the rotary shaft 44, the internal stirring plate 45, and the screen 5 of the screw conveyor 3A can be rotated simultaneously by the drive source device 35 of the screw conveyor 3A. Therefore, these drive devices and rotational force transmission mechanisms can be made compact.

[0071] 3, in the screw conveyor 3A, an annular dam plate 37 is provided on the outer peripheral surface of the one end 324 of the conveyor casing 32. On the other hand, an annular shield plate 525 is provided on the other end of the multiple frames 521, extending from the other end toward the conveyor casing 32 in the radial direction of the screen 5. The dam plate 37 and the annular shield plate 525 are arranged to face each other in close proximity to each other. According to this embodiment, the provision of the weir plate 37 prevents the bed material FM introduced into the screen 5 from the screw conveyor 3A from flowing out into the fluid sand discharge outlet 42 from between the outer surface of the conveyor casing 32 and the annular shield plate 525.

[0072] 6 and 7 are a front view and a side view (a cross-sectional view taken along line BB in FIG. 6) showing a part of a rotary classifier according to still another embodiment. The rotary classifier 4 (4C) according to the embodiment shown in Figures 6 and 7 is provided with an internal stirring plate 45 (45a) or 45 (45b, 45b', 45b'') inside the screen 5, which is provided in the embodiment shown in Figures 3, 4 or 5A to 5C.

[0073] The rotary classifier 4 (4C) is provided with an impact device 48 that is disposed outside the screen 5 and impacts the screen 5 to prevent clogging of the screen 5. The impact device 48 includes at least one cam rail 481 fixed to the outer peripheral surface of the screen 5, and at least one hammer 482 that is disposed so as to be able to slide against the cam rail 481. The cam rail 481 is disposed so that its longitudinal direction extends along the rotation direction of the screen 5, and the hammer 482 is configured so as to be able to collide with or separate from the screen 5 along the shape of the cam rail 481, as shown in FIG.

[0074] Cam rail 481 rotates in the direction of arrow a as screen 5 rotates, and when it reaches a position opposite hammer 482, hammer 482 comes into sliding contact with the outer surface of cam rail 481, then drops from cam rail 481 at the upstream end of screen 5 in the rotation direction, and collides with the outer peripheral surface of screen 5. The impact of hammer 482 colliding with screen 5 removes bed material FM that has become clogged in the sieve meshes of screen 5. Furthermore, because cam rail 481 is fixed to the outer peripheral surface of screen 5, in an embodiment including multiple cam rails 481, the impact timing and impact position of hammer 482 can be adjusted by adjusting the arrangement positions of each cam rail 481.

[0075] 6 and 7, cam rail 481 is made up of a strip-shaped plate and is arranged so that its longitudinal direction follows the circumferential direction of screen 5. Cam rail 481 includes an inclined portion 481a that is arranged downstream in the rotation direction of screen 5, and a parallel portion 481b that is arranged upstream in the rotation direction of screen 5. Inclined portion 481a is arranged at an inclination angle in a direction away from screen 5 with respect to a tangent that contacts the outer peripheral surface of screen 5. Parallel portion 481b is connected to the upstream end of inclined portion 481a, and is arranged at a substantially constant interval from the outer peripheral surface of screen 5.

[0076] The hammer 482 first comes into sliding contact with the outer surface of the inclined portion 481a, then comes into sliding contact with the outer surface of the parallel portion 481b, and then drops from the upstream end of the parallel portion 481b onto the screen 5, striking it. In the illustrated embodiment, a support member 481c for fixing the cam rail 481 to the screen 5 is provided between the outer peripheral surface of the screen 5 and the parallel portion 481b. In addition, the upstream end of the parallel portion 481b is located at a position farther away from the outer peripheral surface of the screen 5 than other portions of the parallel portion 481b in order to increase the impact force of the hammer 482 on the screen 5.

[0077] 7, a struck member 53 is provided that is fixed to the outer peripheral surface of the screen 5, which is the collision point between the screen 5 and the hammer 482. This causes the hammer 482 to strike the struck member 53, and the struck member 53 receives the blow from the hammer 482, thereby improving the durability of the screen 5. 7, the struck member 53 is configured as a plate-shaped reinforcing member extending along the axial direction of the screen 5. The plate-shaped reinforcing member is provided in the front direction of the screen 5 at least at a location where the hammer 482 is provided.

[0078] In one embodiment, a plurality of cam rails 481 are arranged on the outer peripheral surface of the screen 5 along the axial direction of the screen 5. That is, in the axial direction of the screen 5, at least one first cam rail 481A is arranged at a first axial position P1, and at least one second cam rail 481B is arranged at a second axial position P2 that is different from the first axial position P1 in the axial direction of the screen 5. A first hammer 482A is provided at the first axial position P1, and a second hammer 482B is provided at the second axial position P2. The first hammer 482A is arranged to be able to slide on the at least one first cam rail 481A arranged at the first axial position P1, and the second hammer 482B is arranged to be able to slide on the at least one second cam rail 481B arranged at the second axial position P2. The first hammer 482A and the second hammer 482B are configured to strike the screen 5 at different timings.

[0079] According to this embodiment, in the first cam rail 481A and the second cam rail 481B, which are arranged at different axial positions of the screen 5, the impact timing of the first hammer 482A sliding against the first cam rail 481A and the second hammer 482B sliding against the second cam rail 481B is different, so that the impact on the screen 5 and the rotating shaft 44 can be dispersed.

[0080] 7, in one embodiment, at the first axial position P1, a plurality of cam rails 481A are arranged at different positions in the circumferential direction of the screen 5. At least one hammer 482A (shared hammer) is arranged so as to be able to slide on each of the plurality of cam rails 481A arranged at the first axial position P1.

[0081] In this embodiment, at least one hammer 482A arranged at the first axial position P1 slides against multiple cam rails 481A in sequence as the screen 5 rotates, and drops from the upstream end of each cam rail 481A onto the screen 5, impacting the screen 5. According to this embodiment, the screen 5 can be struck a plurality of times using one hammer 482A while the screen 5 makes one rotation at the first axial position P1, and therefore the striking device 48 can be made compact.

[0082] 6 and 7, in one embodiment, a hammer 482 is provided on one end side of an arm 483, and the other end side of the arm 483 is rotatably supported on a rotation shaft 484 arranged outside the screen 5. The hammer 482 is arranged so that the outer peripheral surface of the screen 5 is located on the side where the hammer 482 rotates due to its own weight. According to this embodiment, the screen 5 can be struck by the weight of the hammer 482, eliminating the need for a device for driving the hammer 482. This allows the striking device 48 to be made compact.

[0083] 7, the hammer 482 and the arm 483 are disposed outside the screen 5 and in the inner space of the casing 41. The rotating shaft 484 is supported by a support member 485 fixed to the inner surface of the casing 41. The hammer 482 is formed of a cylindrical body having a volume and specific gravity that can ensure a certain weight.

[0084] Furthermore, the positional relationship between the pivot shaft 484 and the cam rail 481 is such that the pivot shaft 484 is located above the sliding contact position between the cam rail 481 and the hammer 482. This allows the hammer 482 to strike the outer peripheral surface of the screen 5 due to its own weight when the hammer 482 comes off the upstream end of the cam rail 481 in the screen rotation direction.

[0085] In one embodiment, the position where the hammer 482 strikes the screen 5 and the position where the internal stirring plate 45 is positioned are configured not to be close to each other, thereby preventing the bed material FM scooped up by the internal stirring plate 45 from falling due to the impact generated on the screen 5 by the strike. 6 and 7, for example, a plurality of internal agitation plates 45 are arranged at equal intervals around the circumferential direction of the screen 5 at the first axial position P1, and the upstream ends of the plurality of cam rails 481 (the positions where the hammers 482 fall) are arranged at intermediate positions between the plurality of internal agitation plates 45. This makes it possible to prevent the bedrock FM scooped up by the internal agitation plates 45 from falling due to the impact generated on the screen 5 by the impact of the hammers 482.

[0086] (Example) Table 1 shown in FIG. 8 shows the classification performance of a conventional example in which no measures to improve classification performance were taken, a comparative example in which some measures were taken, and an embodiment of a rotary classifier according to the present disclosure. In Table 1, Countermeasure 1 is to arrange a wire brush in sliding contact with the outer peripheral surface of the screen 5, and to scrape off the bed material FM stuck on the sieve surface of the screen 5 while the screen 5 is rotating with the wire brush (Comparative Example 1). Countermeasure 2 is a case in which only the impacting device 48 is provided and the internal stirring plate 45 is not provided, as shown in FIGS. 6 and 7 (Comparative Example 2). Countermeasure 3 is a case in which the rotary classifier 4 (4A) shown in FIGS. 3 and 4 (which is provided with only the internal stirring plate 45 and does not include the impacting device 48) is provided (Embodiment 1). Countermeasure 4 is a case in which both the internal stirring plate 45 and the impacting device 48 are provided, as shown in FIG. 6 and FIG. 7 (Embodiment 2). The classification rates in Table 1 are calculated using the following formula.

number

[0087] From the classification performance of each example shown in Table 1, it can be seen that countermeasures 3 and 4 can exhibit better classification performance than the conventional example and countermeasures 1 and 2.

[0088] The contents described in each of the above embodiments can be understood, for example, as follows.

[0089] 1) A rotary classifier according to one embodiment is a rotary classifier (4) configured to classify fluidized sand (S) and foreign matter (F) contained in a fluidized medium (FM) extracted from a fluidized bed combustion apparatus (2), and includes a rotary shaft (44) extending along a horizontal direction, a cylindrical screen (5) configured to rotate about a center line (CA) of the rotary shaft (44) and configured to transfer the fluidized medium (FM) introduced therein to one side in the axial direction, and an internal stirring plate (45) supported on the rotary shaft (44) side or the screen (5) side, and the internal stirring plate (45) includes a first band-shaped plate (451) having a pair of first long sides (451a, 451b) extending along the axial direction of the screen (5), and a first strip-shaped plate (451) having a pair of first long sides (451a, 451b) extending along the axial direction of the screen (5). and a second band-shaped plate (452) connected to the first band-shaped plate (451), the second band-shaped plate (452) having a pair of second long sides (452a, 452b) extending along the center line (CA) of the rotation shaft (44), wherein in a cross section perpendicular to the center line (CA) of the rotation shaft (44), the first band-shaped plate (451) extends along the radial direction of the screen (5), the second band-shaped plate (452) extends along a direction perpendicular to the radial direction of the screen (5), and an inner first long side (451a) of the pair of first long sides (451a, 451b) located on the inner side in the radial direction of the screen (5) is connected to the second band-shaped plate (452), or an upstream second long side (452a) of the pair of second long sides (452a, 452b) located on the upstream side in the rotation direction is connected to the first band-shaped plate (451).

[0090] According to this configuration, the internal agitator (45) includes the first band-shaped plate (451) and the second band-shaped plate (452) having the above-described configuration, and rotates together with the rotating shaft (44) or the screen (5). Therefore, the bed material (FM) accumulated in the lower part of the screen is scooped up by the first band-shaped plate (451), and is lifted up to the space above the screen (5) while accumulated in the accumulation space (Ss) formed between the first band-shaped plate (451) and the second band-shaped plate (451), and then falls downward. This operation is repeated every time the internal agitator (45) rotates once, thereby improving the agitation effect of the bed material (FM) inside the screen (5). This stirring action separates the fluid sand (S) from the foreign matter (F) and causes it to fall out of the screen (5) through the sieve holes formed in the screen (5), while the foreign matter (F) that is larger in diameter than the fluid sand (S) moves toward the foreign matter discharge port (43) inside the screen 5. This makes it possible to particularly suppress the fluid sand (S) from overshooting toward the foreign matter discharge port (43), thereby improving the classification performance of the fluid sand (S) and foreign matter (F).

[0091] 2) A rotary classifier according to another embodiment is the rotary classifier according to 1), Of the pair of second long sides (452a, 452b), the upstream second long side (452a) located upstream in the direction of rotation is connected to the inner first long side (451a) of the pair of first long sides (451a, 451b) located radially inward of the screen.

[0092] According to this configuration, the upstream second long side (451a) of the pair of second long sides (452a, 452b) is connected to the inner first long side (450a) of the pair of first long sides (451a, 451b), thereby expanding the storage space (Ss) between the first band-shaped plate (451) and the second band-shaped plate (451). This increases the amount of bed material (FM) that can be lifted into the space above the screen (5), thereby further improving the agitation effect of the bed material (FM).

[0093] 3) Another aspect of the rotary classifier is the rotary classifier described in 1) or 2), wherein, in a cross section perpendicular to the center line (CA) of the rotation shaft (44), the angle θ1 formed between the first band-shaped plate (451) and the radial direction of the screen (5) is in the range of -10°≦θ1≦45° (preferably, 10°≦θ1≦45°), with the downstream side of the rotation direction (a) being positive; the angle θ2 formed between the second band-shaped plate (452) and a direction perpendicular to the radial direction of the screen (5) is in the range of -45°≦θ2≦20°, with the lower side being positive; and the angle (θ) formed between the first band-shaped plate (451) and the second band-shaped plate (452) is in the range of 60° or more and 120° or less (preferably, 80° or more and 100° or less).

[0094] With this configuration, the first and second band plates (451, 452) are arranged so that their angles are within the above-mentioned range, and the angle (θ) formed between the first and second band plates (451, 452) is within the above-mentioned range, so that the first band plate (451) can retain the function of scooping up the bed material (FM) accumulated at the bottom inside the screen (5), and the space (Ss) between the first and second band plates (451, 452) can have a volume that can store a sufficient amount of bed material (FM). Furthermore, the second band plate (452) can suppress the bed material (FM) from falling until it rises to the top space (St) inside the screen, depending on the angle of repose of the bed material (FM).

[0095] 4) In yet another aspect of the rotary classifier, in the rotary classifier described in any one of 1) to 3), the rotating shaft (44) includes a shaft main body (441) and a protector (442) formed of a cylindrical body surrounding the shaft main body (441), and the protector (442) is arranged so as to overlap at least a portion of the area in the axial direction of the screen (5) with the area in which the internal stirring plate (45) is arranged.

[0096] According to this configuration, since the protector (442) having the above configuration is provided, the protector (442) can protect the shaft main body (441) from the falling flowable medium (FM), thereby preventing wear of the shaft main body (441).

[0097] 5) In yet another aspect, the rotary classifier is a rotary classifier described in any one of 1) to 4), further comprising at least one connecting bar (47) supported on the rotating shaft (44) and extending along the radial direction of the screen (5), and the internal stirring plate (45) is supported on the rotating shaft (44) via the connecting bar (47).

[0098] According to this configuration, the internal stirring plate (45) is supported by the connecting bar (47), which simplifies the support mechanism for the internal stirring plate (45) and reduces costs. In addition, the weight of the rotated part supported by the rotating shaft (44) can be reduced, which reduces the power of the drive device that rotates the rotating shaft (44).

[0099] 6) In yet another aspect, the rotary classifier is a rotary classifier described in any one of 1) to 5), wherein the length of the internal stirring plate (45) along the axial direction of the screen (5) is shorter than the axial length of the screen (5), and the internal stirring plate (45) is arranged so that the center position of the axial direction of the screen (5) is located upstream of the center position of the axial direction of the screen (5) in the conveying direction of the bed material (FM).

[0100] With this configuration, the internal stirring plate (45) does not extend to the vicinity of the foreign matter side outlet (43) in the axial direction of the screen (5), so that the stirring action of the internal stirring plate (45) can prevent the fluidized sand (S) from being discharged together with the foreign matter (F) from the foreign matter discharge outlet (43).

[0101] 7) In yet another aspect, the rotary classifier is a rotary classifier described in any one of 1) to 6), wherein the rotating shaft (44) and the screen (5) are configured to rotate in the same direction at the same speed, and the rotary classifier is provided with at least one feed blade (51) fixed to the inner peripheral surface of the screen (5) and serving as a feed blade for feeding the flowable medium (FM) inside the screen (5) to the outlet side of the screen (5), the feed blade being arranged at a position different from the internal stirring plate (45) in the circumferential direction of the screen (5).

[0102] With this configuration, the rotating shaft (44) and the screen (5) are configured to rotate in the same direction and at the same speed, allowing a single drive device to serve both the rotating shaft (44) and the screen (5), thereby enabling these drive devices to be made more compact. Furthermore, because the rotating shaft (44) and the screen (5) rotate in the same direction and at the same speed, in an embodiment in which a feed blade (51) for feeding the bed material (FM) from the inlet side to the outlet side of the screen (5) is provided on the inner circumferential surface of the screen (5), the relative positions of the feed blade (51) and the internal agitator (45), which are located at different positions in the circumferential direction of the screen (5), remain unchanged. Therefore, even if the internal agitator (45) and the feed blade (51) are located at the same axial position of the screen (5), there is no risk of interference between the feed blade (51) and the internal agitator (45) during operation of the rotary classifier (4).

[0103] 8) A rotary classifier according to yet another embodiment is a rotary classifier described in any one of 1) to 7), which is provided with at least one cam rail (481) fixed to the outer peripheral surface of the screen (5) and extending along the rotation direction of the screen (5), and at least one hammer (482) arranged to be in sliding contact with the cam rail (481) and capable of colliding with or separating from the screen (5) along the shape of the cam rail (481).

[0104] In this configuration, the hammer (482) slides against the cam rail (481) extending in the rotation direction (a) of the screen (5), drops from the upstream end of the cam rail (481) in the screen rotation direction, and collides with the screen (5). This impact force can remove the flowable medium (FM) or foreign matter (F) that has become stuck in the meshes of the screen (5). Furthermore, because the cam rail (481) is fixed to the outer peripheral surface of the screen (5), when multiple cam rails (481) are provided, the timing and position of impact of the hammer (482) against the screen (5) can be adjusted according to the arrangement positions of the individual cam rails (481).

[0105] 9) In yet another embodiment, the rotary classifier is the rotary classifier described in 8), which is provided with a struck member (53) fixed to the outer peripheral surface of the screen (5), which is the point of collision between the screen (5) and the hammer (482).

[0106] According to this configuration, the screen (5) is provided with a struck member (53) on the outer peripheral surface thereof, which is the point of impact of the hammer (482), thereby improving the durability of the screen (5) against the impacts it receives from the hammer (482).

[0107] 10) A rotary classifier according to yet another aspect is the rotary classifier described in 8) or 9), wherein the at least one cam rail (481) includes at least one first cam rail (481A) arranged at a first axial position (P1) in the axial direction of the screen (5) and at least one second cam rail (481B) arranged at a second axial position (P2) different from the first axial position (P1), the at least one hammer (482) includes a first hammer (482A) arranged at the first axial position (P1) and a second hammer (482B) arranged at the second axial position (P2), and the at least one first cam rail (481A) and the at least one second cam rail (481B) are arranged so that the first hammer (482A) and the second hammer (482B) strike the screen (5) at different timings.

[0108] According to this configuration, in the first cam rail (481A) and the second cam rail (481B) that are arranged at different axial positions of the screen (5), the first hammer (482A) that slides against the first cam rail (481A) and the second hammer (482B) that slides against the second cam rail (481B) strike at different timings, so that the impact on the screen (5) and the rotating shaft (44) can be dispersed.

[0109] 11) A rotary classifier according to yet another aspect is a rotary classifier according to any one of 8) to 10), wherein the at least one cam rail (481) includes a plurality of cam rails (481A) arranged at different circumferential positions of the screen (5) at a first axial position (P1) in the axial direction of the screen (5), and the at least one hammer (482) includes a shared hammer (482A) arranged to be able to slide on each of the plurality of cam rails (481A).

[0110] According to this configuration, at the first axial position (P1), the screen (5) can be struck multiple times using one hammer (482A) against multiple cam rails (481A) arranged at different positions around the circumferential direction of the screen (5) while the screen (5) makes one rotation, thereby making it possible to make the striking device (48) compact.

[0111] 12) A rotary classifier according to yet another embodiment is a rotary classifier described in any one of 8) to 11), which comprises an arm (483) having at least one hammer (482) attached to one end thereof, and a rotating shaft (484) arranged outside the screen (5) and rotatably supporting the other end of the arm (483).

[0112] According to this configuration, the hammer (482) that slides against the outer surface of the cam rail (481) falls from the upstream end of the cam rail (481) in the screen rotation direction onto the sieving surface of the screen (5) due to its own weight, and strikes the screen (5). Therefore, a device for driving the hammer (482) is not required.

[0113] 13) A fluidized bed combustion system according to one embodiment includes a fluidized bed combustion apparatus (2), a rotary classifier (4) described in any one of 1) to 12), and a transfer device (3) configured to transfer the bed material (FM) from the fluidized bed combustion apparatus (2) to the rotary classifier (4).

[0114] According to this configuration, the fluidized bed combustion system (1) includes the rotary classifier (4) having the above-described configurations, which improves the agitation effect of the bed material (FM) within the screen (5), thereby improving the classification performance of the fluidized sand (S) and the foreign matter (F), and in particular, suppressing overshooting of the fluidized sand (S) toward the foreign matter (F). Furthermore, in an embodiment in which at least one set of cam rails (481) and hammers (482) is provided on the outside of the screen (5), the impact force of the hammers (482) colliding with the outer peripheral surface of the screen can remove the bed material (FM) stuck in the sieve meshes of the screen (5), further improving the classification performance of the fluidized sand (S) and the foreign matter (F). [Explanation of symbols]

[0115] 1. Fluidized bed combustion system 12 Primary air intake line 13 Secondary air intake line 14 Fuel introduction line 15 Exhaust gas discharge line 16. Fluid sand supply line 161, 163 Piping 162 Bag filter 164 valves 16A Downstream bed medium supply line 17 Fluid sand introduction line 171 Fluidized sand storage device 172 Junction 173 Pressure pump 18 Switching Device 19 Fluid sand discharge line 2. Fluidized bed combustion equipment 21 Furnace 210 Combustion chamber 211 Fluidized Bed 212 Storage section 213 Upper combustion chamber 22 Side wall 23 Ceiling 24 Furnace bottom 242 Primary air supply port 243 Hearth outlet 25 Heat exchange equipment 251 Flue 252 Heat transfer tube 3 Transfer device 3A screw conveyor 31 Screw shaft 32 Conveyor casing 320 Interior Space 321 Bed medium inlet 322 Fluid medium outlet 324 End 33 Rotating shaft 34 screw blade 35 Drive unit 36 Rotational force transmission member 37 Weir plate 4(4A, 4B, 4B', 4B", 4C) Rotary classifier 41 Casing 42 Fluid sand discharge port 43 Foreign matter outlet 44 Rotation axis 441 Shaft body 442 Protector 442a, 442b semi-cylindrical body 442c Bolt-on plate 442d Reinforcement plate 45(45a, 45b, 45b', 45b") Internal stirring plate 451 First Belt 451a, 451b First long side 452 Second Band Plate 452a, 452b Second long side 453 Shielding plate 46 Bearings 461 Gasket 47 Connecting bar 471, 472 Bar pieces 48 Percussion Device 481 Cam Rail 481A First Cam Rail 481B 2nd Cam Rail 481a Slope 481b Parallel part 481c Support member 482 Hammer 482A First Hammer 482B Second Hammer 483 Arm 484 Rotating shaft 485 Support Member 5 screens 51 Feed blade 52 Support structures 521 Frame 522 Annular frame 523, 524 bars 525 Annular Shield 53 Striking member A1 Primary air A2 Secondary air CS, CA center axis E Exhaust gas F Foreign object FM fluid medium FU fuel P1 1st axis position P2 2nd axis position S fluid sand Ss storage space St top space a Rotation direction b Transfer direction

Claims

1. A rotary classifier configured to classify fluidized sand and foreign matter contained in a fluidized medium extracted from a fluidized bed combustion apparatus, a rotation axis extending along a horizontal direction; A cylindrical screen configured to rotate around a center line of the rotation shaft and configured to transfer the bed material introduced therein to one side in the axial direction; An internal stirring plate supported on the rotating shaft side or the screen side; Equipped with The internal stirring plate is a first band-shaped plate having a pair of first long sides extending along the axial direction of the screen; a second band-shaped plate having a pair of second long sides extending along the axial direction of the screen, the second band-shaped plate being connected to the first band-shaped plate, In a cross section perpendicular to the center line of the rotation shaft, the first band-shaped plate extends along a radial direction of the screen, and the second band-shaped plate extends along a direction perpendicular to the radial direction of the screen, An inner first long side of the pair of first long sides located radially inward of the screen is connected to the second band-shaped plate, or an upstream second long side of the pair of second long sides located upstream in the rotation direction is connected to the first band-shaped plate; Rotary classifier.

2. an upstream second long side of the pair of second long sides that is located upstream in the rotation direction is connected to an inner first long side of the pair of first long sides that is located inside in the radial direction of the screen; The rotary classifier according to claim 1.

3. In a cross section perpendicular to the center line of the rotation axis, an angle θ1 formed between the first belt-shaped plate and a radial direction of the screen is in a range of −10°≦θ1≦45°, with the downstream side in the rotation direction being positive; an angle θ2 formed between the second belt-shaped plate and a direction perpendicular to the radial direction of the screen is in a range of −45°≦θ2≦20°, with the lower side being positive; The angle between the first band-shaped plate and the second band-shaped plate is in the range of 60° to 120°. The rotary classifier according to claim 1 or 2.

4. the rotating shaft includes a shaft main body and a protector formed of a cylindrical body surrounding the shaft main body, The protector is arranged so as to at least partially overlap with the area in which the internal stirring plate is arranged in the axial direction of the screen. The rotary classifier according to claim 1 or 2.

5. The screen further includes at least one connecting bar supported by the rotation shaft and extending along a radial direction of the screen, The internal stirring plate is supported on the rotating shaft via the connecting bar. The rotary classifier according to claim 1 or 2.

6. The length of the internal stirring plate along the axial direction of the screen is shorter than the axial length of the screen, 3. The rotary classifier according to claim 1, wherein the internal stirring plate is arranged so that its center position in the axial direction of the screen is located upstream of the center position of the axial direction of the screen in the conveying direction of the bed material.

7. The rotation shaft and the screen are configured to rotate in the same direction at the same speed, A feed blade is fixed to the inner peripheral surface of the screen and sends the fluidized medium to the outlet side of the screen inside the screen, and at least one feed blade is arranged at a position different from the internal stirring plate in the circumferential direction of the screen. The rotary classifier according to claim 1 or 2.

8. At least one cam rail fixed to the outer peripheral surface of the screen and extending along the rotation direction of the screen; and at least one hammer that is arranged to be in sliding contact with the cam rail and that can collide with or separate from the screen along the shape of the cam rail. The rotary classifier according to claim 1 or 2.

9. a striking member fixed to the outer peripheral surface of the screen, which is a collision point between the screen and the hammer; The rotary classifier according to claim 8.

10. the at least one cam rail includes at least one first cam rail disposed at a first axial position in the axial direction of the screen, and at least one second cam rail disposed at a second axial position different from the first axial position, the at least one hammer includes a first hammer disposed at the first axial position and a second hammer disposed at the second axial position; The at least one first cam rail and the at least one second cam rail are arranged so that the first hammer and the second hammer strike the screen at different times. The rotary classifier according to claim 8.

11. the at least one cam rail includes a plurality of cam rails arranged at different positions in the circumferential direction of the screen at a first axial position in the axial direction of the screen, the at least one hammer includes a shared hammer arranged to be able to slide on each of the plurality of cam rails, The rotary classifier according to claim 8.

12. an arm having the at least one hammer provided on one end thereof; a rotation shaft disposed outside the screen and rotatably supporting the other end of the arm; Equipped with The rotary classifier according to claim 8.

13. a fluidized bed combustor; The rotary classifier according to claim 1; a transfer device configured to transfer the fluidized medium from the fluidized bed combustor to the rotary classifier; A fluidized bed combustion system comprising:

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