Classification equipment and fluidized bed combustion system

Abstract

A classification device that can prevent the structure of the classification device from becoming complicated and large in size, and a fluidized bed combustion system equipped with the classification device are provided. [Solution] The classification device is used to remove foreign matter from a fluidized medium extracted from a fluidized bed combustion device, and comprises an upstream classifier configured to remove small foreign matter smaller than the lower limit value of the fluidized medium from the fluidized medium, and a downstream classifier integrally provided with the upstream classifier, configured to remove large foreign matter larger than the upper limit value of the fluidized medium from the fluidized medium from which small foreign matter has been removed by the upstream classifier.

Description

[Technical Field]

[0001] This disclosure relates to a classifier and a fluidized bed combustion system equipped with the classifier. [Background technology]

[0002] A combustion device using a fluidized bed combustion method is known, in which air is supplied to a fluidized medium (for example, fluidized sand) to make the fluidized medium fluidize, and fuel mixed in the fluidized medium is burned (see, for example, Patent Document 1). Patent Document 1 discloses a fluidized bed incinerator as a combustion device using the fluidized bed combustion method.

[0003] Patent Document 1 discloses a coarse sieve for removing non-combustible minerals from a fluidized bed combustion apparatus, and a fine sieve for extracting fine particles of a predetermined size from the fluidized bed from which the non-combustible minerals have been removed by the coarse sieve. The fine sieve is positioned downstream of the coarse sieve in the direction of fluidized bed transport and at a distance from the coarse sieve. The fluidized bed is transported from the coarse sieve to the fine sieve by transport air. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2003-185104 Summary of the Invention [Problem to be solved by the invention]

[0005] In the fluidized bed boiler equipment described in Patent Document 1, a fine particle sieve is installed immediately before the fluidized bed combustor to prevent fine particles from being mixed into the fluidized bed combustor. Transporting the incombustible minerals using conveying air requires increasing the pressure of the conveying air, which is undesirable, and the coarse particle sieve is therefore located at a distance from the fine particle sieve. This can lead to a complex and large-sized fluidized bed boiler equipment structure, so it is desirable for the fluidized bed boiler equipment to have a simple and compact structure.

[0006] In view of the above circumstances, at least one embodiment of the present disclosure aims to provide a classification device that can prevent the classification device from becoming too complicated and large in size, and a fluidized bed combustion system that includes the classification device. [Means for solving the problem]

[0007] A classification device according to at least one embodiment of the present disclosure includes: A classification device for removing foreign matter from a fluidized bed medium extracted from a fluidized bed combustion apparatus, an upstream classifier configured to remove small foreign matter smaller than a lower limit of the fluid medium from the fluid medium; and a downstream classifier that is integrally provided with the upstream classifier and is configured to remove large foreign matter that is larger than the upper limit value of the fluid medium from the fluid medium from which the small foreign matter has been removed by the upstream classifier.

[0008] A fluidized bed combustion system according to at least one embodiment of the present disclosure comprises: a fluidized bed combustor; The classification device; a transfer device configured to transfer the bed material from the fluidized bed combustion apparatus to the upstream classifier, the transfer device including a screw conveyor configured to be coaxially driven with the upstream classifier; and a return line configured to return the bed material from which the large foreign matter has been removed by the downstream classifier to the fluidized bed combustion apparatus. [Effects of the Invention]

[0009] According to at least one embodiment of the present disclosure, there are provided a classifier that can suppress an increase in the complexity and size of the classifier structure, and a fluidized bed combustion system including the classifier. [Brief explanation of the drawings]

[0010] [Figure 1] This is a schematic diagram of a fluidized bed combustion system according to one embodiment of the present disclosure. [Figure 2] This is a schematic diagram of a fluidized bed combustion apparatus in one embodiment of the present disclosure. [Figure 3] This is a schematic diagram of a fluidized bed combustion apparatus in one embodiment of the present disclosure. [Figure 4] This is a schematic cross-sectional view showing a cross-section along the axis of a classification device and a transfer device according to one embodiment of the present disclosure. [Figure 5] This is an explanatory diagram illustrating the rotation of the classification device shown in Figure 4. [Figure 6] This is a schematic cross-sectional view showing a cross-section along the axis of a classification device and a transfer device according to one embodiment of the present disclosure. [Figure 7] This is a schematic cross-sectional view showing a cross-section along the axis of a classification device and a transfer device according to one embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, several embodiments of the present disclosure will be described with reference to the accompanying drawings. However, the dimensions, materials, shapes, relative arrangements, etc. of components described as embodiments or shown in the drawings are merely illustrative examples and are not intended to limit the scope of the present disclosure.

[0012] (Fluidized Bed Combustion System) Fig. 1 is a schematic configuration diagram of a fluidized bed combustion system 1 according to one embodiment of the present disclosure. As shown in Fig. 1, the fluidized bed combustion system 1 according to some embodiments includes a fluidized bed combustor 2, a classifier 4 for removing foreign matter from the fluidized bed material extracted from the fluidized bed combustor 2, and a transfer device 3 configured to transfer the fluidized bed material from the fluidized bed combustor 2 to the classifier 4.

[0013] (Fluidized bed combustion system) 2 and 3 are schematic configuration diagrams of a fluidized bed combustor 2 according to an embodiment of the present disclosure. As shown in FIGS. 2 and 3, the fluidized bed combustor 2 includes a furnace 21 configured to define a combustion chamber 210 therein. The furnace 21 is configured to fluidize a fluidized medium FM stored in the combustion chamber 210 to form a fluidized bed 211, and to combust a fuel FU introduced into the fluidized bed 211. The fluidized medium FM includes fluidized sand S (e.g., 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] 2 and 3, the furnace 21 has a central axis CF along the vertical direction and is formed in a cylindrical shape extending along the central axis CF. The furnace 21 includes at least one side wall 22 having an inner surface 221 extending along the central axis CF, a ceiling portion 23 having a ceiling surface 231 covering the upper end portion 222 of the side wall 22, and a furnace bottom portion 24 having a bottom surface 241 covering the lower end portion 223 of the side wall 22.

[0015] In the embodiments shown in Figures 2 and 3, the furnace 21 is formed in a rectangular tubular shape, and the aforementioned side wall 22 includes a first side wall 22A and a second side wall 22B located on the opposite side of the central axis CF from the first side wall 22A. In other embodiments, the furnace 21 may be formed in a cylindrical shape.

[0016] The ceiling surface 231 and the bottom surface 241 each extend from the ends of the side wall 22 (upper end 222, lower end 223) toward the side where the central axis CF is located, along a direction intersecting the central axis CF. In the embodiments shown in Figures 2 and 3, the ceiling surface 231 extends along the horizontal direction. The bottom surface 241 is inclined such that the distance from the central axis CF gradually decreases as it moves from the top downwards in the vertical direction.

[0017] The combustion chamber 210 is defined by an inner surface 221 of the side wall 22, a ceiling surface 231 of the ceiling portion 23, and a bottom surface 241 of the furnace bottom portion 24. The combustion chamber 210 includes a storage portion 212 configured to store a fluidized medium on the bottom surface 241 of the furnace bottom portion 24, and an upper combustion chamber 213 located above the storage portion 212 in the vertical direction.

[0018] In the embodiment shown in Figure 2, the bottom surface 241 of the furnace bottom 24 has at least one (multiple in the illustrated example) primary air supply port 242 and a fluidized medium outlet 243. The primary air supply port 242 and the fluidized medium outlet 243 each communicate with the storage section 212. The primary air supply port 242 is formed at a position further from the central axis CF than the fluidized medium outlet 243 in a direction perpendicular to the central axis CF. The side wall 22 (for example, the first side wall 22A) has at least one secondary air supply port 225, an exhaust gas outlet 226, and a fluidized medium supply port 224. The secondary air supply port 225, the exhaust gas outlet 226, and the fluidized medium supply port 224 each communicate with the upper combustion chamber 213. The side wall 22 (for example, the second side wall 22B) also has a fuel supply port 227 that communicates with the upper combustion chamber 213.

[0019] In the embodiment shown in Figure 2, the fluidized bed combustion system 1 includes a primary air introduction line 12 configured to supply primary air (fluidized air) to the storage section 212 vertically upward via a primary air supply port 242. The primary air introduction line 12 supplies primary air from outside the furnace 21 to the fluidized medium FM stored in the storage section 212. The fluidized medium FM stored on the bottom surface 241 of the furnace bottom 24 is fluidized by the primary air supplied vertically upward from the primary air supply port 242, forming the fluidized bed 211 described above in the lower part of the combustion chamber 210.

[0020] In the embodiment shown in Figure 3, the fluidized bed combustion system 1 includes at least one diffuser pipe 26 disposed in the storage section 212 and configured to supply primary air (fluidized air) to the storage section 212. The diffuser pipe 26 has at least one (multiple in the illustrated example) primary air supply port 261 that connects the inside and outside of the diffuser pipe 26. The primary air sent into the diffuser pipe 26 is sent through the primary air supply port 261 to the fluidized medium FM stored in the storage section 212. The fluidized medium FM stored in the furnace bottom section 24 is fluidized by the primary air supplied from the primary air supply port 261, forming the fluidized bed 211 described above in the lower part of the combustion chamber 210.

[0021] In the embodiment shown in Figure 3, the diffuser pipe 26 extends horizontally and passes through a pair of opposing side walls 22 (in the illustrated example, a first side wall 22A and a second side wall 22B) that straddle the storage section 212. Multiple primary air supply ports 261 are formed at intervals along the extending direction of the diffuser pipe 26 in the portion of the diffuser pipe 26 that exists within the storage section 212. The multiple primary air supply ports 261 open in a direction along the horizontal, so that primary air is supplied horizontally from the inside to the outside (i.e., to the storage section 212) of the diffuser pipe 26.

[0022] As shown in Figures 2 and 3, the fluidized bed combustion system 1 further includes a secondary air introduction line 13 configured to send secondary air (combustion air) to the upper combustion chamber 213 through at least one secondary air supply port 225 in the side wall 22, and a fuel introduction line 14 configured to send fuel FU to the storage section 212 through a fuel supply port 227 in the side wall 22.

[0023] Secondary air is sent from outside the furnace 21 to the upper combustion chamber 213 via a secondary air introduction line 13. Furthermore, fuel is sent to the storage section 212 from a fuel storage device 11 (e.g., a hopper, see FIG. 1 ) that is provided outside the furnace 21 and configured to store fuel, via a fuel introduction line 14. The fuel sent to the storage section 212 is combusted in a fluidized bed 211 in which a fluidized medium is fluidized. Furthermore, unburned fuel and unburned pyrolysis gas in the exhaust gas generated by the above combustion are completely combusted by the secondary air in the upper combustion chamber 213.

[0024] In the illustrated embodiment, the fluidized bed combustion system 1 further includes an exhaust gas discharge line 15 configured to discharge exhaust gas from the combustion chamber 210 to the outside of the furnace 21 through the exhaust gas discharge port 226 in the side wall 22, as shown in Figures 2 and 3.

[0025] In the illustrated embodiment, the fluidized bed combustor 2 includes a fluidized bed boiler 2A as shown in Figures 2 and 3. The fluidized bed boiler 2A includes the furnace 21 described above and a heat exchanger 25 configured to recover thermal energy generated by combustion in the furnace 21. 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 the fluidized bed boiler 2A (a configuration that does not include the heat exchanger 25).

[0026] In the illustrated embodiment, the heat exchanger 25 includes a heat transfer tube 252 provided in a flue 251 located downstream in the flow direction of the exhaust gas from the upper combustion chamber 213 of the furnace 21. The heat transfer tube 252 recovers thermal energy from the exhaust gas flowing through the flue 251. Note that, 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 medium, or a furnace wall tube that forms the side wall 22 (first side wall 22A, second side wall 22B) of the furnace 21 and recovers thermal energy from the exhaust gas and pyrolysis gas in the combustion chamber 210.

[0027] (Large foreign object) The fluidized bed combustor 2 is capable of burning a variety of fuels (e.g., bituminous coal, lignite, petroleum coke, woody biomass, paper sludge, refuse-derived fuel (RDF) / RPF (refuse-derived fuel), waste tires, etc.) and has high combustion efficiency. These various fuels may contain large foreign matter (LF) larger than the upper limit of the bed material. The upper limit of the bed material refers to the maximum particle diameter (maximum particle size) of the fluidized sand constituting the bed material, and large foreign matter (LF) refers to particles with a minimum diameter larger than the maximum particle size of the fluidized sand. For example, when woody biomass, such as wood chips or construction waste, is used as fuel, nails, metal objects, gravel, and the like may be contained as large foreign matter. For this reason, as shown in Figures 2 and 3, the fuel FU sent to the storage unit 212 via the fuel inlet line 14 and the bed material FM (fluidized sand S) stored in the storage unit 212 may contain large foreign matter (LF).

[0028] (small foreign body) The fluidized medium FM (fluid sand S) stored in the storage section 212 may contain small foreign matter SF that is smaller than the lower limit of the fluidized medium. The lower limit of the fluidized medium refers to the minimum diameter (minimum particle size) of the fluidized sand particles that make up the fluidized medium, which is set in advance, and small foreign matter SF refers to particles whose maximum diameter is smaller than the minimum particle size of the fluidized sand.

[0029] If the proportion of foreign matter contained in the fluidized medium 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 is extracted from the storage section 212 of the furnace 21, the foreign matter is removed from the extracted fluidized medium, and then it is returned to the storage section 212.

[0030] In the illustrated embodiment, the fluidized bed combustion system 1 further includes a fluidized bed circulation line 16 configured to extract the fluidized bed material (fluid sand which may contain small foreign matter SF and large foreign matter LF) stored in the storage section 212 of the furnace 21 to the outside of the furnace 21, remove the large foreign matter LF and small foreign matter SF from the extracted fluidized bed material using a classifier 4, and then return the extracted fluidized bed material to the inside of the furnace 21, as shown in Figure 1, and a fluidized bed introduction line 17 configured to send the fluidized bed material from a fluidized bed material storage device 171 (e.g., a hopper) provided outside the furnace 21 and configured to store the fluidized bed material to the storage section 212 of the furnace 21.

[0031] The transfer device 3 and the classifier 4 are each provided on the bed material circulation line 16. The transfer device 3 is provided upstream of the classifier 4 in the flow direction of the bed material flowing through the bed material circulation line 16, and is configured to transfer the bed material extracted from the fluidized bed combustor 2 to the classifier 4. The classifier 4 is configured to separate the bed material (fluid sand) contained in the bed material extracted from the fluidized bed combustor 2 and falling within the range between the upper and lower limit values ​​of the bed material from large foreign matter LF and small foreign matter SF.

[0032] In the illustrated embodiment, the bed material introduction line 17 merges with the bed material circulation line 16 at a junction 172 located downstream of the classifier 4 in the flow direction of the bed material (fluid sand) in the bed material circulation line 16. Transfer equipment such as piping located downstream of the junction 172 of the bed material circulation line 16 and the bed material introduction line 17 in the flow direction of the bed material (near the bed material supply port 224) is shared by the bed material circulation line 16 and the bed material introduction line 17.

[0033] The fluid medium circulation line 16 includes a pipe 161 connecting the classifier 4 and the junction 172, and a valve 164 (e.g., an on-off valve) provided in the pipe 161. The pipe 161 extends vertically. The fluid medium discharged from the classifier 4 falls through the pipe 161 and is sent to the junction 172. The fluid medium introduction line 17 includes a pressurized blower (or pressurized fan) 173 located upstream of the junction 172 in the flow direction for pressurizing the fluid medium downstream in the flow direction. The pressurized blower 173 is a shared piece of equipment also used for pressurizing the fluid medium located at the junction 172 of the fluid medium circulation line 16 and downstream of the junction 172. In another embodiment, the bed material circulation line 16 and the bed material introduction line 17 may be provided independently, and the bed material in the bed material circulation line 16 may be pumped by a pumping blower provided in the bed material circulation line 16.

[0034] In the illustrated embodiment, the fluidized bed combustion system 1 further comprises a switching device 18 provided in the fluidized medium circulation line 16, and a fluidized medium discharge line 19 branching off from the fluidized medium circulation line 16 for extracting the fluidized medium from the fluidized medium circulation line 16, as shown in Figure 1. The switching device 18 and the fluidized medium discharge line 19 are each provided downstream of the confluence 172 in the direction of fluidized medium flow. The switching device 18 is configured to switch the destination of the fluidized medium to either the portion of the fluidized medium circulation line 16 downstream of the switching device 18 in the direction of fluidized medium flow (downstream fluidized medium circulation line 16A) or the fluidized medium discharge line 19.

[0035] When the destination of the fluidized medium by the switching device 18 is set to the downstream fluidized medium circulation line 16A, the fluidized medium pumped by the pressure blower 173 is sent through the downstream fluidized medium circulation line 16A and into the combustion chamber 210 of the furnace 21 via the fluidized medium supply port 224. Alternatively, when the destination of the fluidized medium by the switching device 18 is set to the fluidized medium discharge line 19, the fluidized medium pumped by the pressure blower 173 is discharged outside the fluidized bed combustion system 1 through the fluidized medium discharge line 19.

[0036] In the illustrated embodiment, the fluidized bed combustion system 1 also includes a bag filter 162 provided in the bed material circulation line 16, as shown in Fig. 1. The bag filter 162 collects the bed material passing through the bag filter 162. In the embodiment shown in Fig. 1, the bag filter 162 is provided between the junction 172 and the switching device 18.

[0037] (transfer device) 4, 6, and 7 are schematic cross-sectional views showing cross sections along the axis of the classifier 4 and the transfer device 3 (the central axis CA1 of the first screen 51) according to an embodiment of the present disclosure. In FIGS. 4, 6, and 7, the screw blades 34 of the screw shaft 31 are omitted. FIG. 5 is an explanatory diagram for explaining the rotation of the classifier 4 shown in FIG. 4. The transfer device 3 is provided upstream of the classifier 4 in the flow direction of the bed material flowing through the bed material circulation line 16, and is configured to transfer the bed material extracted from the fluidized bed combustion apparatus 2 to the classifier 4. In the illustrated embodiment, 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.

[0038] The screw conveyor 3A includes at least one screw shaft 31 and a conveyor casing 32 that houses the at least one screw shaft 31. The screw shaft 31 includes a rotating shaft 33 that extends along a central axis CS, and screw blades 34 that are provided to protrude spirally from the outer periphery of the rotating shaft 33. In the illustrated embodiment, the central axis CS of the rotating shaft 33 extends horizontally, but it may also be inclined so that the downstream side is located lower than the upstream side in the transfer direction of the flowable medium, or so that the downstream side is located higher than the upstream side in the transfer direction of the flowable medium.

[0039] The screw conveyor 3A is configured to rotate the screw shaft 31 with its central axis CS as the center of rotation. In the illustrated embodiment, the screw conveyor 3A further includes a drive source device 35 that generates rotational force to rotate the screw shaft 31, and a rotational force transmission member 36 connected to the drive source device 35 and the screw shaft 31, which transmits rotational force from the drive source device 35 to the screw shaft 31. The drive source device 35 can be, for example, a motor. The rotational force transmission member 36 can be, for example, a coupling.

[0040] The screw conveyor 3A is configured to rotate the screw shaft 31 to capture the fluid medium (which may include small foreign matter SF and large foreign matter LF) in the gaps between the pitches of the screw blades 34, and to transfer the captured fluid medium from one side in the axial direction in which the central axis CS extends (left side in Figure 1) to the other side, that is, from the upstream side to the downstream side in the transfer direction of the fluid medium in the screw conveyor 3A.

[0041] The conveyor casing 32 defines an internal space 320 that houses the screw shaft 31. The conveyor casing 32 has a fluid medium inlet 321 for introducing the fluid medium into the internal space 320, and a fluid medium outlet 322 for discharging the fluid medium transferred to the screw shaft 31 from the internal space 320 to the outside. The fluid medium inlet 321 is formed on one side of the ceiling surface 323 of the conveyor casing 32 in the axial direction to which the central axis CS extends. The fluid medium outlet 322 is formed at the other end 324 of the conveyor casing 32 in the axial direction to which the central axis CS extends.

[0042] In the illustrated embodiment, the fluidized medium circulation line 16 includes a pipe 163 connecting the fluidized medium outlet 243 of the furnace 21 and the fluidized medium inlet 321 of the conveyor casing 32. The pipe 163 extends vertically. The fluidized medium 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.

[0043] In the illustrated embodiment, the other end 324 of the conveyor casing 32 is inserted into the cylindrical first screen 51 of the classifier 4. The first screen 51 may be positioned downstream of the other end 324 of the conveyor casing 32 in the direction of fluid transfer. The fluid sent into the internal space 320 of the conveyor casing 32 is transferred downstream in the transfer direction within the internal space 320 by the screw shaft 31 and supplied into the first screen 51 through the fluid discharge port 322.

[0044] (classifier) In some embodiments, the classifier 4 is configured to separate the fluidized medium (fluidized sand) contained in the fluidized medium extracted from the fluidized bed combustion device 2, which falls within the range of upper and lower limits of the fluidized medium, from large foreign matter LF and small foreign matter SF. As shown in Figures 1, 4, 6, and 7, the classifier 4 comprises an upstream classifier 5 and a downstream classifier 6 located downstream of the upstream classifier 5 in the fluidized medium transfer direction.

[0045] The upstream classifier 5 is configured to remove small foreign matter SF smaller than the lower limit of the fluid medium from the fluid medium. The downstream classifier 6 is configured to remove large foreign matter LF larger than the upper limit of the fluid medium from the fluid medium from which the small foreign matter SF has been removed by the upstream classifier 5. The downstream classifier 6 is integrally installed with the upstream classifier 5. Here, "the downstream classifier 6 is integrally installed with the upstream classifier 5" means that the fluid medium from which the small foreign matter SF has been removed by the upstream classifier 5 is quickly guided to the downstream classifier 6, and the classification of the fluid medium and small foreign matter SF in the upstream classifier 5 and the classification of the fluid medium and large foreign matter LF in the downstream classifier 6 are carried out continuously.

[0046] According to the classifying device 4, small foreign matter SF can be removed from the fluid medium by the upstream classifier 5, and large foreign matter LF can be removed from the fluid medium by the downstream classifier 6. By integrating the downstream classifier 6 with the upstream classifier 5, the fluid medium from which small foreign matter SF has been removed by the upstream classifier 5 can be quickly transferred to the downstream classifier 6. In this case, the transfer structure for transferring the fluid medium containing large foreign matter LF from the upstream classifier 5 to the downstream classifier 6 can be simplified, thereby preventing the classifying device 4 from becoming larger and more complex. Furthermore, when the upstream classifier 5 capable of removing small foreign matter SF is provided upstream of the downstream classifier 6 capable of removing large foreign matter LF in the direction of fluid medium transfer, the structure of the classifying device 4 including the upstream classifier 5 and the downstream classifier 6 can be prevented from becoming larger and more complex than when the upstream classifier 5 capable of removing small foreign matter SF is provided downstream of the downstream classifier 6 in the direction of fluid medium transfer.

[0047] (Screen 1) In some embodiments of the classification device 4, the upstream classifier 5 includes a first screen 51. The first screen 51 is a cylindrical body extending along a central axis CA1 (axial line) of the first screen 51 and having an outer peripheral surface 511 and an inner peripheral surface 512. The first screen 51 is configured to be rotatable about the central axis CA1. The first screen 51 is configured such that, by rotating the first screen 51 about the axis, the bed material is transferred from one side (left side in FIG. 1 ) in the axial direction along which the central axis CA1 (axial line) extends to the other side, i.e., from the upstream side to the downstream side in the transfer direction of the bed material on the first screen 51. In the illustrated embodiment, the central axis CA1 of the first screen 51 extends horizontally, but may be inclined so that the downstream side is positioned lower than the upstream side in the transfer direction of the bed material, or so that the downstream side is positioned higher than the upstream side in the transfer direction of the bed material.

[0048] The first screen 51 has sieve openings 52 corresponding to the lower limit of the fluid medium. The sieve openings 52 are through holes that penetrate from the outer circumferential surface 511 to the inner circumferential surface 512 of the first screen 51, and multiple sieve openings 52 are formed on the first screen 51. The multiple sieve openings 52 are arranged, for example, in a staggered pattern on the first screen 51. Each of the multiple sieve openings 52 is configured to be able to classify based on the lower limit of the fluid medium. In other words, each of the multiple sieve openings 52 is configured to allow small foreign matter SF smaller than the lower limit of the fluid medium to pass through, while preventing fluid medium larger than the lower limit of the fluid medium and large foreign matter LF from passing through.

[0049] The first screen 51 is configured to remove small foreign matter SF from the fluid medium introduced into the first screen 51 and to transfer the fluid medium from which the small foreign matter SF has been removed to the downstream classifier 6. When the first screen 51 is rotated around its axis, the small foreign matter SF contained in the fluid medium inside the first screen 51 is drawn out from the sieve 52 to the radially outward side of the first screen 51 and discharged to the outside of the first screen 51. When the first screen 51 is rotated around its axis, the fluid medium that is larger than the sieve 52 cannot pass through the sieve 52 because its outer diameter is larger than the sieve 52, and is transferred to the other side in the axial direction of the first screen 51, and is discharged from the first screen side discharge port 513 defined by the other side edge of the inner circumferential surface 512 of the first screen 51.

[0050] The fluid medium introduced into the first screen 51 is transferred from one axial side to the other as the first screen 51 rotates around its axis. During this transfer, small foreign matter SF passes through the sieve mesh 52 of the first screen 51, thereby removing the small foreign matter SF. The fluid medium from which the small foreign matter SF has been removed is transferred by the rotation of the first screen 51 and discharged to the outside of the first screen 51 from the other axial end of the first screen 51, and is guided to the downstream classifier 6. In this case, by rotating the first screen 51 around its axis, it is possible to classify the fluid medium from small foreign matter SF and the fluid medium that is larger than the lower limit, and the fluid medium from which the small foreign matter SF has been removed can be guided to the downstream classifier 6. Therefore, it is possible to suppress the complexity and size increase of the structure of the classification device 4, which includes an upstream classifier 5 and a downstream classifier 6.

[0051] (Screen 2) In some embodiments of the classification apparatus 4, as shown in Figures 1, 4, and 6, the downstream classifier 6 described above includes a second screen 61. The second screen 61 is a cylindrical body that extends along the central axis CA2 (axis) of the second screen 61 and has an outer circumferential surface 611 and an inner circumferential surface 612, and is configured to be rotatable about the central axis CA2 as the center of rotation. The second screen 61 is configured to transfer the fluid medium from one side in the axial direction on which the central axis CA2 (axis) extends (left side in Figure 1) to the other side, that is, from the upstream side to the downstream side in the transfer direction of the fluid medium in the second screen 61, by rotating the second screen 61 about its axis.

[0052] In the illustrated embodiment, the second screen 61 is configured such that the extension direction of the central axis CA2 is parallel to the extension direction of the central axis CA1 of the first screen 51 and transports the fluid medium in the same direction as the direction of transport of the fluid medium by the first screen 51. In the illustrated embodiment, the central axis CA2 of the second screen 61 extends horizontally, but may be inclined so that the downstream side is positioned lower than the upstream side in the direction of transport of the fluid medium, or so that the downstream side is positioned higher than the upstream side in the direction of transport of the fluid medium. In some other embodiments, the second screen 61 may be configured to transport the fluid medium in the opposite direction to the direction of transport of the fluid medium by the first screen 51. Transporting the fluid medium in the same direction as the direction of transport of the fluid medium by the first screen 51 can simplify the structure of the classifier 4 compared to transporting the fluid medium in the opposite direction to the direction of transport of the fluid medium by the first screen 51.

[0053] The second screen 61 has sieve meshes 62 corresponding to the upper limit of the bed material. The sieve meshes 62 are through-holes that penetrate from the outer peripheral surface 611 to the inner peripheral surface 612 of the second screen 61, and multiple sieve meshes 62 are formed on the second screen 61. The multiple sieve meshes 62 are arranged, for example, in a staggered pattern on the second screen 61. Each of the multiple sieve meshes 62 is configured to be able to classify the bed material based on the upper limit of the bed material. In other words, each of the multiple sieve meshes 62 is configured to allow bed material smaller than the upper limit of the bed material to pass through, and to prevent large foreign matter LF larger than the upper limit of the bed material from passing through.

[0054] The second screen 61 is configured to remove large foreign matter LF from the fluid medium from which small foreign matter SF introduced into the second screen 61 has been removed. When the second screen 61 is rotated around its axis, fluid medium smaller than the upper limit of the fluid medium inside the second screen 61 is drawn out radially outward from the sieve 62 and discharged to the outside of the second screen 61. When the second screen 61 is rotated around its axis, large foreign matter LF, which is larger than the upper limit of the fluid medium inside the second screen 61, cannot pass through the sieve 62 because its outer diameter is larger than the sieve 62, and is transported to the other side in the axial direction of the second screen 61, and is discharged from the large foreign matter discharge port 613 defined by the other side edge of the inner circumferential surface 612 of the second screen 61.

[0055] The fluid medium from which small foreign matter has been removed is transported by the rotation of the first screen 51 and guided into the second screen 61 from the other axial end 53 of the first screen 51. The fluid medium introduced into the second screen 61 is transported from one axial side to the other as the second screen 61 rotates around its axis. During transport, fluid medium smaller than the upper limit passes through the sieve 62 of the second screen 61, leaving large foreign matter LF inside the second screen 61. The large foreign matter LF remaining inside the second screen 61 is transported by the rotation of the second screen 61 and discharged to the outside of the second screen 61 from the other axial end 53 of the second screen 61. In this case, by rotating the second screen 61 around its axis, the large foreign matter LF and fluid medium smaller than the upper limit can be separated, thus suppressing the complexity and size of the downstream classifier 6.

[0056] In the classification device 4 according to some embodiments, as shown in FIGS. 1 and 4 , the second screen 61 has an inner diameter larger than the outer diameter of the first screen 51 and is disposed so as to surround the outer periphery of the downstream end 53 of the first screen 51 in the direction of transfer of the flowable medium. In the illustrated embodiment, the second screen 61 includes a surrounding portion 61A that surrounds the outer periphery of the first screen 51 on the one axial side of the first screen outlet 513, and a protruding portion 61B that protrudes on the other axial side of the first screen outlet 513. The first screen 51 has a portion on the upstream side of the first screen 51 in the direction of transfer of the flowable medium that is not surrounded by the second screen 61. The flowable medium discharged from the first screen outlet 513 falls onto the inner periphery 612 of the second screen 61.

[0057] By arranging the second screen 61 to surround the outer periphery of the downstream end 53 of the first screen 51, the bed material discharged to the outside of the first screen 51 due to the rotation of the first screen 51 is quickly guided into the second screen 61. Furthermore, by arranging the second screen 61 to surround the outer periphery of the downstream end 53 of the first screen 51, the axial length of the classifier 4 including the first screen 51 and the second screen 61 can be shortened, and the structure of the classifier 4 can be prevented from becoming too complex and large.

[0058] 6 , in the classification device 4 according to some embodiments, the second screen 61 is arranged next to the first screen 51 on the downstream side in the transfer direction of the fluid medium through the first screen 51. In the illustrated embodiment, the extension direction of the central axis CA2 of the second screen 61 is the same as the extension direction of the central axis CA1 of the first screen 51. The second screen 61 is configured to transfer the fluid medium in the same direction as the transfer direction of the fluid medium through the first screen 51, downstream of the first screen 51 in the transfer direction of the fluid medium. The fluid medium discharged from the first screen side discharge port 513 is introduced onto the inner circumferential surface 612 of the second screen 61.

[0059] In the illustrated embodiment, the second screen 61 has an outer diameter that is the same as the outer diameter of the first screen 51, and an inner diameter that is the same as the inner diameter of the first screen 51. The outer diameter of the second screen 61 may be larger or smaller than the outer diameter of the first screen 51. The inner diameter of the second screen 61 may be larger or smaller than the inner diameter of the first screen 51. By making the outer diameter of the second screen 61 the same as or smaller than the outer diameter of the first screen 51, the radial length (maximum outer diameter) of the classifier 4 including the first screen 51 and the second screen 61 can be reduced, and the structure of the classifier 4 can be prevented from becoming too complex or large.

[0060] By arranging the second screen 61 next to the first screen 51 on the downstream side in the transfer direction of the bed material, the bed material discharged to the outside of the first screen 51 due to the rotation of the first screen 51 is quickly guided into the inside of the second screen 61. Furthermore, by arranging the second screen 61 next to the first screen 51 on the downstream side in the transfer direction of the bed material, the structure of the classifier 4 including the first screen 51 and the second screen 61 can be simplified, and the structure of the classifier 4 can be prevented from becoming too complex and large.

[0061] 6, in the classifying device 4 according to some embodiments, the second screen 61 is integrally formed with the first screen 51. By forming the second screen 61 integrally with the first screen 51, the structure of the classifying device 4 including the first screen 51 and the second screen 61 can be simplified, and the structure of the classifying device 4 can be prevented from becoming too complex and large.

[0062] In the classification device 4 according to some embodiments, the downstream classifier 6 is a vibration classifier, as shown in Fig. 7. The downstream classifier 6 includes a sieve surface 71 having sieve openings 72 corresponding to the upper limit of the flowable medium, and a vibration mechanism 73 configured to vibrate the sieve surface 71.

[0063] The sieve surface 71 may be one surface of the flat plate-like member 70. The sieve meshes 72 are through holes that penetrate the flat plate-like member 70 in the thickness direction, and multiple sieve meshes 72 are formed on the sieve surface 71. The multiple sieve meshes 72 are arranged, for example, in a staggered pattern on the sieve surface 71. In the illustrated embodiment, the sieve surface 71 is arranged horizontally, but the sieve surface 71 may also be arranged at an angle relative to the horizontal direction. Each of the multiple sieve meshes 72 is configured to be capable of classifying based on the upper limit value of the bed material. In other words, each of the multiple sieve meshes 72 is configured to allow bed material smaller than the upper limit value of the bed material to pass through, and to prevent large foreign matter LF larger than the upper limit value of the bed material from passing through.

[0064] The downstream classifier 6 is configured to remove large foreign matter from the bed material from which small foreign matter has been removed and which has been placed on the sieve surface 71. When the sieve surface 71 is vibrated by the vibration mechanism 73, bed material smaller than the upper limit on the sieve surface 71 is extracted through the sieve openings 72 below the sieve surface 71 and discharged outside the downstream classifier 6. When the sieve surface 71 is vibrated by the vibration mechanism 73, large foreign matter LF larger than the upper limit of the bed material on the sieve surface 71 cannot pass through the sieve openings 72 because its outer shape is larger than the sieve openings 72, and it remains on the sieve surface 71. The large foreign matter LF remaining on the sieve surface 71 is transported by the vibration of the sieve surface 71 and is discharged from a large foreign matter discharge port provided in the downstream classifier 6.

[0065] By vibrating the sieve surface 71 using the vibration mechanism 73, vibration is applied to the bed material that has been placed on the sieve surface 71 and from which small foreign objects have been removed, and bed material that is smaller than the upper limit passes through the sieve openings 72 of the sieve surface 71, leaving large foreign objects on the sieve surface 71. The large foreign objects that remain on the sieve surface 71 are transported by the vibration of the sieve surface 71 and discharged outside the downstream classifier 6. In this case, by vibrating the sieve surface 71, it is possible to separate the large foreign objects from the bed material that is smaller than the upper limit, thereby preventing the downstream classifier 6 from becoming too large and complicated in structure.

[0066] In the classification device 4 according to some embodiments, as shown in Fig. 7, the downstream classifier 6 described above includes an introduction section 74 for guiding the bed material, from which small foreign matter has been removed, onto the sieve surface 71, the introduction section 74 having an introduction port 741 provided below the downstream end 53 of the first screen 51 in the direction of transfer of the bed material. The bed material discharged from the first screen-side discharge port 513 falls downward, passes through the introduction port 741, and is guided onto the sieve surface 71 via the introduction section 74. The introduction port 741 may be provided above the sieve surface 71 in a vertical plan view.

[0067] By providing the inlet 741 of the introduction section 74 below the downstream end 53 of the first screen 51, the bed material discharged outside the first screen 51 due to the rotation of the first screen 51 is quickly guided onto the sieve surface 71. In such a classifier 4, by arranging the downstream classifier 6, which has a simple structure, near the first screen 51, it is possible to prevent the structure of the classifier 4 from becoming too complicated and large.

[0068] The fluidized medium circulation line 16 described above includes a return line 16B configured to return the fluidized medium, from which small foreign matter SF has been removed by the upstream classifier 5 and large foreign matter LF has been removed by the downstream classifier 6, back to the fluidized bed combustion device 2. The return line 16B includes a pipe 161 connecting the classifier 4 and the junction 172.

[0069] In a fluidized bed combustion system 1 according to some embodiments, as shown in FIG. 4, the transfer device 3 includes a screw conveyor 3A configured to be driven coaxially with the upstream classifier 5. The first screen 51 may be configured to rotate at the same rotational speed as the screw shaft 31. Note that the "rotational speed" in this disclosure may simply mean the number of rotations, or may mean the average rotational speed per predetermined time.

[0070] In the illustrated embodiment, the first screen 51 is mechanically coupled to the screw shaft 31 and is configured to rotate about its axis by transmitting the rotational force of the screw shaft 31. Specifically, as shown in FIGS. 4 and 5 , the classifier 4 includes an annular coupling member 41 attached to the outer periphery of the screw shaft 31, and at least one (four in FIG. 5 ) rod-shaped connecting member 42 extending along the radial direction of the screw shaft 31 and mechanically connecting the coupling member 41 and the first screen 51. The connecting member 42 has a radially inner end fixed to the coupling member 41 and a radially outer end fixed to the first screen 51. The first screen 51 is supported by the screw shaft 31, so that it can be driven coaxially with the screw shaft 31 and can rotate at the same rotational speed as the screw shaft 31.

[0071] By configuring the screw conveyor 3A of the transfer device 3 to be driven coaxially with the upstream classifier 5, a dedicated drive device for driving the upstream classifier 5 is not required, thereby preventing the structure of the fluidized bed combustion system 1 equipped with the transfer device 3 and the classifier 4 from becoming too complex and large.

[0072] 4, in the fluidized bed combustion system 1 according to some embodiments, the transfer device 3 includes a screw conveyor 3A configured to coaxially drive the upstream classifier 5 and the downstream classifier 6. The second screen 61 may be configured to rotate at the same rotational speed as the screw shaft 31 and the first screen 51.

[0073] In the illustrated embodiment, the second screen 61 is mechanically connected to the screw shaft 31 via the first screen 51, and is configured to rotate about its axis by transmitting the rotational force of the screw shaft 31. Specifically, as shown in Figures 4 and 5, the classifier 4 includes at least one (four in Figure 5) rod-shaped connecting member 43 that extends radially of the screw shaft 31 and mechanically connects the first screen 51 and the second screen 61.

[0074] The connecting member 43 has its radially inner end fixed to the first screen 51 and its radially outer end fixed to the second screen 61. The second screen 61 is supported by the screw shaft 31 via the first screen 51, so that it is driven coaxially with the screw shaft 31 and can rotate at the same rotational speed as the screw shaft 31. In some other embodiments, the second screen 61 may be mechanically connected to the screw shaft 31 without going through the first screen 51, for example, the connecting member 43 may have its radially inner end fixed to the connecting member 41.

[0075] By configuring the screw conveyor 3A of the transfer device 3 to be driven coaxially with the upstream classifier 5 and the downstream classifier 6, a dedicated drive device for driving the upstream classifier 5 and the downstream classifier 6 becomes unnecessary, thereby suppressing the complexity and size increase of the fluidized bed combustion system 1, which includes the transfer device 3 and the classifier 4.

[0076] In this specification, expressions describing relative or absolute arrangements such as "in a certain direction," "along a certain direction," "parallel," "orthogonal," "center," "concentric," or "coaxial" shall not only describe such arrangements strictly, but also describe states of relative displacement with tolerances or angles or distances that allow for the same function to be achieved. 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. Furthermore, in this specification, expressions representing shapes such as a rectangular shape or a cylindrical shape not only represent rectangular shapes or cylindrical shapes 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. Furthermore, in this specification, the expressions "comprise," "include," or "have" a component are not exclusive expressions that exclude the presence of other components.

[0077] This disclosure is not limited to the embodiments described above, but also includes modified forms of the embodiments described above, as well as forms that combine these forms as appropriate.

[0078] The contents of the above-described embodiments can be understood, for example, as follows.

[0079] 1) A classification apparatus (4) according to at least one embodiment of the present disclosure is: A classifier (4) for removing foreign matter from a fluidized bed medium discharged from a fluidized bed combustion apparatus (2), An upstream classifier (5) configured to remove small foreign matter smaller than the lower limit of the fluid medium from the fluid medium, and a downstream classifier (6) that is provided integrally with the upstream classifier (5) and is configured to remove large foreign matter that is larger than the upper limit value of the fluid medium from the fluid medium from which the small foreign matter has been removed by the upstream classifier (5).

[0080] According to the configuration of 1) above, small foreign matter can be removed from the fluid medium by the upstream classifier (5), and large foreign matter can be removed from the fluid medium by the downstream classifier (6). By integrating the downstream classifier (6) with the upstream classifier (5), the fluid medium from which small foreign matter has been removed by the upstream classifier (5) can be quickly transferred to the downstream classifier (6). In this case, the transfer structure for transferring the fluid medium containing large foreign matter from the upstream classifier (5) to the downstream classifier (6) can be simplified, thereby preventing the classifier (4) from becoming larger and more complex. Furthermore, when the upstream classifier (5) capable of removing small foreign matter is provided upstream of the downstream classifier (6) capable of removing large foreign matter in the direction of transfer of the fluid medium, the complexity and size of the structure of the classification device (4) equipped with the upstream classifier (5) and the downstream classifier (6) can be reduced compared to when the classifier is provided downstream of the downstream classifier (6) in the direction of transfer of the fluid medium.

[0081] 2) In some embodiments, the classification apparatus (4) described in 1) above, The upstream classifier (5) The device includes a cylindrical first screen (51) that can rotate around an axis, has sieve meshes (52) that correspond to the lower limit value of the bed material, and is configured to remove small foreign matter from the bed material that has been introduced into the first screen (51) and transport the bed material from which the small foreign matter has been removed to the downstream classifier (6).

[0082] According to the configuration of 2) above, the bed material introduced into the first screen (51) is transferred from one side of the first screen (51) in the axial direction to the other side as the first screen (51) rotates about its axis. During transfer, small foreign objects pass through the meshes (52) of the first screen (51), thereby removing the small foreign objects. The bed material from which the small foreign objects have been removed is transferred by the rotation of the first screen (51) and discharged from the other end of the first screen (51) in the axial direction, and then guided to the downstream classifier (6). In this case, rotating the first screen (51) about its axis separates small foreign objects from bed material larger than the lower limit, and also guides the bed material from which the small foreign objects have been removed to the downstream classifier (6). This prevents the structure of the classifier (4) including the upstream classifier (5) and the downstream classifier (6) from becoming too complex and large.

[0083] 3) In some embodiments, the classification apparatus (4) described in 2) above, The downstream classifier (6) is, The second screen (61) is a cylindrical second screen (61) that is rotatable around an axis and has a mesh size (62) corresponding to the upper limit of the fluid medium, and is configured to remove large foreign matter from the fluid medium from which small foreign matter has been introduced into the second screen (61).

[0084] According to the configuration 3) above, the bed material from which small foreign matter has been removed is transferred by the rotation of the first screen (51) and introduced into the second screen (61) from the other axial end of the first screen (51). The bed material introduced into the second screen (61) is transferred from one axial side of the second screen (61) to the other axial side as the second screen (61) rotates about its axis. During transfer, bed material smaller than the upper limit passes through the meshes (62) of the second screen (61), leaving large foreign matter inside the second screen (61). The large foreign matter remaining inside the second screen (61) is transferred by the rotation of the second screen (61) and is discharged to the outside of the second screen (61) from the other axial end of the second screen (61). In this case, by rotating the second screen (61) around its axis, large foreign matter and flowable medium smaller than the upper limit can be separated, thereby preventing the downstream classifier (6) from becoming too complex and large in size.

[0085] 4) In some embodiments, the classification device (4) described in 2) above, The downstream classifier (6) is, a sieve surface (71) having sieve openings (72) corresponding to the upper limit value of the flowable medium; a vibration mechanism (73) configured to vibrate the sieve surface (71), The sieve is configured to remove the large foreign matter from the fluidized medium from which the small foreign matter has been removed and which has been thrown onto the sieve surface (71).

[0086] According to the configuration 4) above, the vibration mechanism (73) vibrates the sieve surface (71), thereby vibrating the bed material that has been placed on the sieve surface (71) and from which small foreign objects have been removed. As a result, bed material that is smaller than the upper limit passes through the sieve openings (72) of the sieve surface (71), and large foreign objects remain on the sieve surface (71). The large foreign objects that remain on the sieve surface (71) are transported by the vibration of the sieve surface (71) and discharged outside the downstream classifier (6). In this case, vibrating the sieve surface (71) can separate the large foreign objects from the bed material that is smaller than the upper limit, thereby preventing the downstream classifier (6) from becoming too complex and large in size.

[0087] 5) In some embodiments, the classification device (4) described in 3) above, The second screen (61) was disposed so as to surround the outer periphery of the downstream end of the first screen (51) in the direction of transfer of the fluidized medium.

[0088] According to the configuration in 5) above, by arranging the second screen (61) to surround the outer circumference of the downstream end of the first screen (51), the fluidized medium discharged to the outside of the first screen (51) by the rotation of the first screen (51) is quickly guided into the inside of the second screen (61). Furthermore, according to the configuration in 5) above, the axial length of the classifier (4) equipped with the first screen (51) and the second screen (61) can be made shorter, thereby suppressing the complexity and size increase of the structure of the classifier (4).

[0089] 6) In some embodiments, the classification device (4) described in 3) above, The second screen (61) was arranged next to the first screen (51) on the downstream side in the transport direction of the flowable medium in the first screen (51).

[0090] According to the configuration in 6) above, by arranging the second screen (61) downstream of the first screen (51) in the direction of fluid transfer, the fluid discharged to the outside of the first screen (51) due to the rotation of the first screen (51) is quickly guided into the inside of the second screen (61). Furthermore, according to the configuration in 6) above, the structure of the classifier (4) equipped with the first screen (51) and the second screen (61) can be simplified, and the complexity and size of the classifier (4) can be suppressed.

[0091] 7) In some embodiments, the classification device (4) described in 6) above, The second screen (61) was formed integrally with the first screen (51).

[0092] According to the configuration of 7) above, by configuring the second screen (61) integrally with the first screen (51), the structure of the classification device (4) including the first screen (51) and the second screen (61) can be simplified, and the structure of the classification device (4) can be prevented from becoming complicated and large.

[0093] 8) In some embodiments, the classification device (4) described in 4) above, The downstream classifier (6) is, The apparatus includes an introduction section (74) for guiding the bed material from which the small foreign matter has been removed onto the sieve surface, the introduction section (74) having an introduction port provided below the downstream end of the first screen (51) in the direction of transfer of the bed material.

[0094] According to the configuration of 8), the inlet of the introduction section (74) is provided below the downstream end of the first screen (51), so that the flowable medium discharged to the outside of the first screen (51) due to the rotation of the first screen (51) is quickly guided into the second screen (61). Furthermore, according to the configuration of 8), the downstream classifier (6) with a simple structure is disposed near the first screen (51), so that the structure of the classifier (4) can be prevented from becoming complicated and large.

[0095] 9) At least one embodiment of the fluidized bed combustion system (1) of the present disclosure includes: a fluidized bed combustor (2); A classification device (4) according to any one of 1) to 8) above; a transfer device (3) configured to transfer the fluidized medium from the fluidized bed combustion apparatus (2) to the upstream classifier (5), the transfer device (3) including a screw conveyor (3A) configured to be driven coaxially with the upstream classifier (5); and a return line (16B) configured to return the bed material from which the large foreign matter has been removed by the downstream classifier (6) to the fluidized bed combustion apparatus (2).

[0096] According to the configuration described in 9) above, by configuring the screw conveyor (3A) of the transfer device (3) to be driven coaxially with the upstream classifier (5), a dedicated drive device for driving the upstream classifier (5) becomes unnecessary, thereby suppressing the complexity and size increase of the structure of the fluidized bed combustion system (1) equipped with the transfer device (3) and the classifier (4).

[0097] 10) A fluidized bed combustion system (1) according to at least one embodiment of the present disclosure is a fluidized bed combustor (2); A classification apparatus (4) described in any of the above 3), 5) to 7), a transfer device (3) configured to transfer the fluidized medium from the fluidized bed combustion apparatus (2) to the upstream classifier (5), the transfer device (3) including a screw conveyor (3A) configured to coaxially drive each of the upstream classifier (5) and the downstream classifier (6); and a return line (16B) configured to return the bed material from which the large foreign matter has been removed by the downstream classifier (6) to the fluidized bed combustion apparatus (2).

[0098] According to the configuration described in 10) above, by configuring the screw conveyor (3A) of the transfer device (3) to be coaxially driven with the upstream classifier (5) and the downstream classifier (6), a dedicated drive device for driving the upstream classifier (5) and the downstream classifier (6) becomes unnecessary, thereby suppressing the complexity and size increase of the structure of the fluidized bed combustion system (1) equipped with the transfer device (3) and the classifier (4). [Explanation of symbols]

[0099] 1. Fluidized bed combustion system 2. Fluidized bed combustion equipment 2A fluidized bed boiler 3 Transfer device 3A screw conveyor 4 Classifier 5 Upstream classifier 6 Downstream classifier 11 Fuel storage device 12 Primary air intake line 13 Secondary air intake line 14 Fuel Injection Line 15 Exhaust gas discharge line 16 Bed medium circulation line 16A Downstream bed material circulation line 16B Return line 17 Bed media introduction line 18 Switching device 19 Bed media discharge line 21 Furnace 24 Furnace bottom 25 Heat exchange equipment 31 Screw shaft 32 Conveyor casing 33 Rotating shaft 34 screw blade 35. Power source device 36 Rotational force transmission member 41 Connecting member 42, 43 Connecting member 51 Screen 1 52,62,72 phloem 61 Screen 2 71 Sieve surface 73 Vibration mechanism section 74 Introduction CA1 Central axis of the first screen CA2 Second Screen Central Axis CF central axis of the furnace CS Screw Shaft Central Axis FM fluid medium LF Large Physics S fluid sand SF small foreign object

Claims

1. A classification device for removing foreign matter from a fluidized bed medium extracted from a fluidized bed combustion apparatus, an upstream classifier configured to remove small foreign matter smaller than a lower limit of the fluid medium from the fluid medium; a downstream classifier provided integrally with the upstream classifier, the downstream classifier being configured to remove large foreign matter larger than an upper limit value of the fluid medium from the fluid medium from which the small foreign matter has been removed by the upstream classifier, Classifying device.

2. The upstream classifier is a cylindrical first screen rotatable about an axis, having sieve openings corresponding to a lower limit value of the bed material, and configured to remove small foreign matter from the bed material introduced into the first screen and to transfer the bed material from which the small foreign matter has been removed to the downstream classifier; The classification device according to claim 1 .

3. The downstream classifier is a cylindrical second screen rotatable about an axis, having sieve openings corresponding to an upper limit value of the bed material, and configured to remove large foreign matter from the bed material from which the small foreign matter has been removed and which has been introduced into the second screen; The classification device according to claim 2 .

4. The downstream classifier is A sieve surface having a mesh size corresponding to the upper limit of the fluid medium, It includes a vibration mechanism configured to vibrate the sieve surface, The system is configured to remove large foreign matter from the fluid medium from which the small foreign matter introduced onto the sieve surface has been removed. The classification device according to claim 2 .

5. The second screen is arranged to surround the outer circumference of the downstream end of the first screen in the direction of transfer of the fluid medium, The classification device according to claim 3.

6. The second screen is positioned alongside the first screen on the downstream side in the direction of transfer of the fluid medium in the first screen, The classification device according to claim 3.

7. The second screen is configured to be integrated with the first screen. The classification device according to claim 6.

8. The downstream classifier is an introduction section for guiding the bed material from which the small foreign matter has been removed onto the sieve surface, the introduction section having an introduction port provided below an end of the first screen on the downstream side in the transfer direction of the bed material; The classification device according to claim 4.

9. a fluidized bed combustor; The classification device according to any one of claims 1 to 8, a transfer device configured to transfer the bed material from the fluidized bed combustion apparatus to the upstream classifier, the transfer device including a screw conveyor configured to be coaxially driven with the upstream classifier; a return line configured to return the bed material from which the large foreign matter has been removed by the downstream classifier to the fluidized bed combustion apparatus, Fluidized bed combustion system.

10. a fluidized bed combustor; The classification device according to any one of claims 3 and 5 to 7, a transfer device configured to transfer the fluidized medium from the fluidized bed combustion apparatus to the upstream classifier, the transfer device including a screw conveyor configured to coaxially drive each of the upstream classifier and the downstream classifier; a return line configured to return the bed material from which the large foreign matter has been removed by the downstream classifier to the fluidized bed combustion apparatus, Fluidized bed combustion system.

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