Ash removal system

Abstract

To provide an ash removal system capable of suppressing variation of ash accumulation amount at a plurality of positions in a boiler and of suppressing deterioration of heat exchange efficiency of the boiler.SOLUTION: An ash removal system for removing ash accumulated in a heat transfer pipe group provided in a boiler includes: at least one pressure wave generation device for generating pressure wave; at least one movable nozzle configured to be movable in the boiler to release the pressure wave generated in the at least one pressure wave generation device; a monitoring device for monitoring an accumulation state of ash accumulated in heat transfer pipes of the heat transfer pipe groups at each of the plurality positions in the boiler; and a control device configured to control at least one of a position or direction of each tip of the at least one movable nozzle on the basis of the accumulation state monitored by the monitoring device.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to an ash removal system.

Background Art

[0002] Since ash accumulates in the heat transfer tube group provided in the boiler, an ash removal system for removing ash may be provided to suppress a decrease in the heat transfer performance of the heat transfer tube group.

[0003] As the ash removal system, there are a method using a soot blower and a method using a pressure wave (shock pulse). The method using a pressure wave can be used more frequently than a conventional soot blower, and its operation control becomes important.

[0004] Patent Document 1 and Patent Document 2 disclose installing a pressure wave generator upstream of a heat transfer bank or in a radiation chamber in a waste incinerator, and controlling the pressure wave generator using a pressure difference between the furnace pressure and the boiler outlet pressure or the gas temperature at the inlet of the heat transfer bank as a control factor.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0006] In the operation control of Patent Document 1 and Patent Document 2, it is difficult to grasp the local ash deposition state, such as where the ash deposition amount has increased in the boiler. Further, since the position where the pressure wave is emitted is also fixed, the position where the ash removal effect is easily obtained and the position where it is difficult to obtain are fixed, and unevenness in the ash deposition amount is likely to occur. For this reason, the ash removal effect becomes insufficient at positions where the ash deposition amount is relatively large or at positions far from the position where the pressure wave is emitted, and there is a possibility that the gap between the heat transfer tubes is blocked by ash and the heat exchange efficiency of the boiler is greatly reduced.

[0007] In view of the above circumstances, at least one embodiment of the present disclosure aims to provide an ash removal system that can suppress unevenness in the ash deposition amount at a plurality of positions in a boiler and suppress a decrease in the heat exchange efficiency of the boiler.

Means for Solving the Problems

[0008] To achieve the above object, an ash removal system according to at least one embodiment of the present disclosure is an ash removal system for removing ash deposited on a heat transfer tube group provided in a boiler, at least one pressure wave generator for generating a pressure wave, at least one movable nozzle configured to be movable within the boiler and to emit the pressure wave generated by the at least one pressure wave generator, a monitoring device for monitoring the deposition state of ash deposited on the heat transfer tubes of the heat transfer tube group at each of a plurality of positions within the boiler, a control device configured to control at least one of the position and orientation of the tip of each of the at least one movable nozzle based on the deposition state monitored by the monitoring device, and includes.

Effects of the Invention

[0009] According to at least one embodiment of the present disclosure, there is provided an ash removal system that can suppress unevenness in the ash deposition amount at a plurality of positions in a boiler and suppress a decrease in the heat exchange efficiency of the boiler.

Brief Description of the Drawings

[0010]

Figure 1

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Figure 17

Embodiments for Carrying Out the Invention

[0011] Hereinafter, some embodiments of the present disclosure will be described with reference to the accompanying drawings. However, the dimensions, materials, shapes, relative arrangements, etc. of the components described as embodiments or shown in the drawings are not intended to limit the scope of the invention thereto, but are merely illustrative examples. For example, expressions representing relative or absolute arrangements such as "in a certain direction", "along a certain direction", "parallel", "orthogonal", "center", "concentric", or "coaxial" not only strictly represent such arrangements, but also represent states in which there are tolerances or relative displacements with angles and distances that can obtain the same function. For example, expressions representing that things such as "identical", "equal", and "homogeneous" are in an equal state not only strictly represent an equal state, but also represent states in which there are tolerances or differences that can obtain the same function. For example, expressions representing shapes such as a rectangular shape or a cylindrical shape not only represent shapes such as a rectangular shape or a cylindrical shape in a geometrically strict sense, but also represent shapes including concave and convex portions, chamfered portions, etc. within a range where the same effect can be obtained. On the other hand, the expressions "comprising", "having", "including", or "possessing" a component do not exclude the existence of other components.

[0012] FIG. 1 is a diagram showing a schematic configuration of a boiler system 2 according to an embodiment. The boiler system 2 includes a boiler 4 and an ash removal system 6. In the illustrated exemplary embodiment, the boiler 4 includes a stoker-type incinerator 8 (stoker furnace) and an exhaust gas passage 9 through which the exhaust gas (combustion gas generated by incinerating waste in the incinerator 8) that has exited the incinerator 8 flows. The exhaust gas passage 9 includes a first radiant chamber 10, a second radiant chamber 12, and a convective heat transfer chamber 14.

[0013] The incinerator 8 is configured to burn the waste received from the waste inlet 16 while moving it on a stoker 18 (grate) and discharge it from the waste outlet 20.

[0014] The upper part of the incinerator 8 is connected to the lower part of the first radiant chamber 10, and the first radiant chamber 10 extends, for example, along the vertical direction so as to guide the exhaust gas discharged from the incinerator 8 upward. The wall surface of the first radiant chamber 10 is constituted by a water-cooled wall 26. The water-cooled wall 26 of the first radiant chamber 10 includes, for example, as shown in FIG. 2, a plurality of heat transfer tubes 28 (furnace wall tubes) and a plurality of fins 29 that connect adjacent heat transfer tubes 28 among the plurality of heat transfer tubes 28.

[0015] As shown in FIG. 1, the upper part of the first radiant chamber 10 is connected to the upper part of the second radiant chamber 12 via a turning part 22 for turning the flow of the exhaust gas from upward to downward. The second radiant chamber 12 extends along the vertical direction so as to guide the exhaust gas downward. The wall surface of the second radiant chamber 12 is constituted by a water-cooled wall 27. The water-cooled wall 27 of the second radiant chamber 12 includes, for example, as shown in FIG. 2, a plurality of heat transfer tubes 28 (furnace wall tubes) and a plurality of fins 29 that connect adjacent heat transfer tubes 28 among the plurality of heat transfer tubes 28.

[0016] The lower part of the second radiation chamber 12 is connected to the convection heat transfer chamber 14 via a turning part 24 for turning the flow of combustion gas from downward to upward. The convection heat transfer chamber 14 extends along the vertical direction so as to guide the flow of combustion gas upward. Inside the convection heat transfer chamber 14, a plurality of heat transfer banks 30 are arranged at intervals in the vertical direction. The plurality of heat transfer banks 30 may include, for example, a superheater and an economizer. Each of the plurality of heat transfer banks 30 is constituted by, for example, a heat exchanger in which a plurality of heat transfer tubes 32 arranged in the horizontal direction are provided in multiple stages in the vertical direction.

[0017] In the above configuration, the exhaust gas discharged from the incinerator 8 rises in the first radiation chamber 10 while exchanging heat with the water-cooled wall 26 of the first radiation chamber 10, and flows into the second radiation chamber 12 from the upper part of the first radiation chamber 10 via the turning part 22. The exhaust gas flowing into the second radiation chamber 12 descends in the second radiation chamber 12 while exchanging heat with the water-cooled wall 27 of the second radiation chamber 12, and flows into the convection heat transfer chamber 14 from the lower part of the second radiation chamber 12 via the turning part 24. The exhaust gas flowing into the convection heat transfer chamber 14 rises in the convection heat transfer chamber 14 while exchanging heat with each of the plurality of heat transfer banks 30, and flows to the further downstream side of the exhaust gas passage 9 from the upper part of the convection heat transfer chamber 14.

[0018] In the above configuration, the plurality of heat transfer tubes 28 constituting the water-cooled wall 26 of the first radiation chamber 10, the plurality of heat transfer tubes 28 constituting the water-cooled wall 27 of the second radiation chamber 12, and the plurality of heat transfer tubes 32 constituting each of the plurality of heat transfer banks 30 constitute the heat transfer tube group 35 of the boiler 4.

[0019] As shown in FIG. 1, the ash removal system 6 includes a plurality of pressure wave generators 36 for generating pressure waves (shock pulses), a plurality of movable nozzles 38 for discharging the pressure waves generated by each of the plurality of pressure wave generators, a monitoring device 40 for monitoring the deposition state of ash deposited on the heat transfer tubes (the heat transfer tubes 28 of the water-cooled wall 26, the heat transfer tubes 28 of the water-cooled wall 27, and the heat transfer tubes 32 of the heat transfer bank 30) of the heat transfer tube group 35 for each of a plurality of positions in the boiler 4, and a control device 42.

[0020] In the illustrated exemplary embodiment, the plurality of pressure wave generators 36 includes a pressure wave generator 36A disposed above the boiler 4 and a pressure wave generator 36B disposed below the boiler 4. Specifically, the pressure wave generator 36A is provided above the first radiation chamber 10 and on a vertical line passing through the first radiation chamber 10. The pressure wave generator 36B is provided below the second radiation chamber 12 and on a vertical line passing through the second radiation chamber 12. Also, the distance between the pressure wave generator 36A and the first radiation chamber 10 is smaller than the distance between the pressure wave generator 36A and the convective heat transfer chamber 14, and the pressure wave generator 36A is disposed closer to the first radiation chamber 10 than the convective heat transfer chamber 14. Further, the distance between the pressure wave generator 36B and the second radiation chamber 12 is smaller than the distance between the pressure wave generator 36B and the convective heat transfer chamber 14, and the pressure wave generator 36B is disposed closer to the second radiation chamber 12 than the convective heat transfer chamber 14.

[0021] The plurality of movable nozzles 38 includes a plurality of movable nozzles 38A for discharging the pressure wave generated by the pressure wave generator 36A and a plurality of movable nozzles 38B for discharging the pressure wave generated by the pressure wave generator 36B.

[0022] The plurality of movable nozzles 38A includes a movable nozzle 38A1 provided corresponding to the first radiation chamber 10 and capable of discharging a pressure wave to the first radiation chamber 10, a movable nozzle 38A2 provided corresponding to the upper part of the second radiation chamber 12 and capable of discharging a pressure wave to the upper part of the second radiation chamber 12, and a movable nozzle 38A3 provided corresponding to the upper part of the convective heat transfer chamber 14 and capable of discharging a pressure wave to the upper part of the convective heat transfer chamber 14. The plurality of movable nozzles 38B includes a movable nozzle 38B1 provided corresponding to the lower part of the second radiation chamber 12 and capable of discharging a pressure wave to the lower part of the second radiation chamber 12, and a movable nozzle 38B2 provided corresponding to the lower part of the convective heat transfer chamber 14 and capable of discharging a pressure wave to the lower part of the convective heat transfer chamber 14. Each of the movable nozzles 38 is configured to be stretchable and capable of changing the direction of the tip of the movable nozzle 38 (for example, the angle with respect to the vertical direction), and by only stretching the movable nozzle 38, the tip thereof reaches the height of the floor level of each heat transfer bank 30.

[0023] Also, in the illustrated example, the distance between the pressure wave generator 36A and the inlet of the pressure wave of the movable nozzle 38A1 (the proximal end of the movable nozzle 38A1) is smaller than the distance between the pressure wave generator 36A and the inlet of the pressure wave of the movable nozzle 38A3 (the proximal end of the movable nozzle 38A3). Further, the distance between the pressure wave generator 36B and the inlet of the pressure wave of the movable nozzle 38B1 (the proximal end of the movable nozzle 38B1) is smaller than the distance between the pressure wave generator 36B and the inlet of the pressure wave of the movable nozzle 38B2 (the proximal end of the movable nozzle 38B2).

[0024] In the illustrated exemplary embodiment, the ash removal system 6 includes a first pipe portion 44A that is connected to the pressure wave generator 36A and through which the pressure wave generated by the pressure wave generator 36A passes, and a plurality of second pipe portions 45A1 to 45A3 that connect the first pipe portion 44A and the plurality of movable nozzles 38A1 to 38A3, respectively. Further, the ash removal system 6 includes a valve 46A1 provided between the connection position of the second pipe portion 45A1 and the connection position of the second pipe portion 45A2 in the first pipe portion 44A, a valve 46A2 provided between the connection position of the second pipe portion 45A2 and the connection position of the second pipe portion 45A3 in the first pipe portion 44A, and a plurality of valves 47A1 to 47A3 provided in the plurality of second pipe portions 45A1 to 45A3, respectively. The valve 47A1 is provided in the second pipe portion 45A1, the valve 47A2 is provided in the second pipe portion 45A2, and the valve 47A3 is provided in the second pipe portion 45A3.

[0025] Also, in the illustrated exemplary embodiment, the ash removal system 6 includes a first pipe portion 44B that is connected to the pressure wave generator 36B and through which the pressure wave generated by the pressure wave generator 36B passes, and a plurality of second pipe portions 45B1 and 45B2 that connect the first pipe portion 44B and the plurality of movable nozzles 38B1 and 38B2, respectively. Further, the ash removal system 6 includes a valve 46B1 provided between the connection position of the second pipe portion 45B1 and the connection position of the second pipe portion 45B2 in the first pipe portion 44B, a valve 46B2 provided between the connection position of the second pipe portion 45B2 and the connection position of the second pipe portion 45A3 in the first pipe portion 44B, and a plurality of valves 47B1 and 47B2 provided in the plurality of second pipe portions 45B1 and 45B2, respectively. The valve 47B1 is provided in the second pipe portion 45B1, and the valve 47B2 is provided in the second pipe portion 45B2.

[0026] Also, in the illustrated exemplary embodiment, the monitoring device 40 includes at least one visible camera 51 (a plurality of visible cameras 51 in the illustrated example) for monitoring the deposition state of ash deposited on the heat transfer tubes of the heat transfer tube group 35 (the heat transfer tubes 28 of the water-cooled wall 26, the heat transfer tubes 28 of the water-cooled wall 27, and the heat transfer tubes 32 of the heat transfer bank 30) at each of a plurality of positions within the boiler 4. In this case, the monitoring device 40 may include a plurality of visible cameras 51 for monitoring the deposition state of the above ash at each of a plurality of positions within the boiler 4, and a plurality of scales 52 (see FIG. 3) respectively provided at a plurality of positions within the boiler 4. The scale 52 may be, for example, an ash adhesion detection plate having a length serving as a reference for measuring the deposition thickness of ash, or may be a ruler having graduations or the like.

[0027] In the example shown in FIG. 3, each of the plurality of scales 52 is fixed so as to stand upright along the ash deposition direction on the heat transfer tubes (the heat transfer tubes 32 in the example shown in FIG. 3) constituting the heat transfer tube group 35. The plurality of scales 52 may include a plurality of scales 52 having different heights at different positions in the length direction (the extending direction of the heat transfer tubes) of the heat transfer tubes, as shown in FIG. 3. In the configuration shown in FIG. 3, by taking an image including the scale 52 and the ash deposited in the vicinity of the scale 52 through the viewing window 53 of the boiler 4 by the visible camera 51, it is possible to monitor whether the deposition thickness of ash at the position of the scale 52 is equal to or greater than a threshold value. Also, as shown in FIG. 3, the above image may be taken while illuminating the scale 52 with light from the light source 54.

[0028] Note that the configuration of the monitoring device 40 is not limited to the above-described configuration. For example, as shown in FIG. 4, for each of a plurality of positions in the boiler 4, at least one laser displacement meter 55 may be included for monitoring the deposition state of ash deposited on the heat transfer tubes of the heat transfer tube group 35 (the heat transfer tubes 28 of the water wall 26, the heat transfer tubes 28 of the water wall 27, and the heat transfer tubes 32 of the heat transfer bank 30). In the example shown in FIG. 4, a laser is irradiated from the laser displacement meter 55 along the length direction of the heat transfer tube 32 at a predetermined height from the heat transfer tube 32, and the laser displacement meter 55 receives the laser reflected from the ash, thereby monitoring whether the deposition thickness of the ash deposited on the heat transfer tube 32 is equal to or greater than a threshold value, and grasping the position where the deposition thickness of the ash becomes equal to or greater than the threshold value. The monitoring device 40 may include a plurality of laser displacement meters 55 for respectively monitoring the deposition state of the ash at a plurality of positions in the boiler 4.

[0029] Further, the monitoring device 40 may include at least one optical fiber thermometer 56 for monitoring the deposition state of ash at a plurality of positions of the heat transfer tube group 35, for example, as shown in FIG. 5. In the example shown in FIG. 5, the optical fiber thermometer 56 is provided along the length direction of the heat transfer tube 32 on the surface of the heat transfer tube 32. Thereby, the optical fiber thermometer 56 can measure the temperature at each position in the length direction of the heat transfer tube 32. During the operation of the boiler 4, the temperature at each position in the length direction of the heat transfer tube 32 changes depending on the deposition state of the ash at each position, and the temperature decreases as the deposition thickness of the ash increases. Therefore, by measuring the temperature at each position in the length direction of the heat transfer tube 32 with the optical fiber thermometer 56 and monitoring whether the temperature at each position in the length direction of the heat transfer tube 32 is equal to or greater than a threshold value, the deposition state of the ash at each position in the length direction of the heat transfer tube 32 can be determined.

[0030] FIG. 6 is a diagram showing an example of the hardware configuration of the control device 42 shown in FIG. 1. FIG. 7 is a block diagram showing an example of the functional configuration of the control device 42. FIG. 8 is a diagram showing an example of the ash removal control flow by the control device 42.

[0031] As shown in FIG. 6, the control device 42 is configured by using a computer including, for example, a processor 72, a RAM (Random Access Memory) 74, a ROM (Read Only Memory) 76, an HDD (Hard Disk Drive) 78, an input I / F 80, and an output I / F 82, which are connected to each other via a bus 84. Note that the hardware configuration of the control device 42 is not limited to the above, and it may be configured by a combination of a control circuit and a storage device. Further, the control device 42 is configured by a computer executing a program that realizes each function of the control device 42. The functions of each part in the control device 42 described below are realized by, for example, loading a program held in the ROM 76 into the RAM 74 and executing it by the processor 72, and reading and writing data in the RAM 74 and the ROM 76.

[0032] As shown in FIG. 7, the control device 42 includes a pressure wave path control unit 60, a movable nozzle control unit 61, and a pressure wave control unit 62.

[0033] As shown in FIG. 8, in S101, the monitoring device 40 monitors the deposition state of ash deposited on the heat transfer tubes of the heat transfer tube group 35 (the heat transfer tubes 28 of the water-cooled wall 26, the heat transfer tubes 28 of the water-cooled wall 27, and the heat transfer tubes 32 of the heat transfer bank 30).

[0034] In S102, for each of a plurality of positions in the boiler 4 monitored in S101, it is determined whether a parameter related to the ash deposition state is equal to or greater than a threshold value. Here, the parameter related to the ash deposition state may be the ash deposition thickness measured as described above by the visible camera 51 or the laser displacement meter 55 when the monitoring device 40 includes the visible camera 51 or the laser displacement meter 55, or may be the temperature measured as described above by the optical fiber thermometer 56 when the monitoring device 40 includes the optical fiber thermometer 56.

[0035] In S102, for each of a plurality of positions in the boiler 4 monitored in S101, if the parameter regarding the ash deposition state is not equal to or greater than the threshold value, the process returns to S101 and the monitoring device 40 continues to monitor the ash deposition state.

[0036] In S102, for at least one position among the plurality of positions in the boiler 4 monitored in S101, if the parameter regarding the ash deposition state is equal to or greater than the threshold value, in S103, the pressure wave path control unit 60 controls the valves 46A1, 46A2, 47A1 to 47A3, 46B1, 47B1, 47B2 so as to send a pressure wave to the movable nozzle 38 (preferably the movable nozzle 38 closest to the position where the parameter regarding the ash deposition state becomes equal to or greater than the threshold value) corresponding to the position where the parameter regarding the ash deposition state becomes equal to or greater than the threshold value.

[0037] In FIG. 1, for example, when the parameter regarding the ash deposition state becomes equal to or greater than the threshold value at a position in the first radiant chamber 10, the pressure wave path control unit 60 opens the valve 47A1 corresponding to the movable nozzle 38A1 and closes the other valves 46A1, 46A2, 47A2, 47A3, 46B1, 47B1, 47B2.

[0038] In FIG. 1, for example, when the parameter regarding the ash deposition state becomes equal to or greater than the threshold value at the upper part in the second radiant chamber 12, the pressure wave path control unit 60 opens the valves 46A1, 47A2 corresponding to the movable nozzle 38A2 and closes the other valves 46A2, 47A1, 47A3, 46B1, 47B1, 47B2.

[0039] In FIG. 1, for example, when the parameter regarding the ash deposition state becomes equal to or greater than the threshold value at the lower part in the second radiant chamber 12, the pressure wave path control unit 60 opens the valve 47B1 corresponding to the movable nozzle 38B1 and closes the other valves 46A1, 46A2, 47A1 to 47A3, 46B1, 47B2.

[0040] In FIG. 1, for example, when the parameter regarding the ash deposition state in the upper part of the convection heat transfer chamber 14 becomes equal to or greater than the threshold value, the pressure wave path control unit 60 opens the valves 46A1, 46A2, 47A3 corresponding to the movable nozzle 38A3, and closes the other valves 47A1, 47A2, 46B1, 47B1, 47B2.

[0041] In FIG. 1, for example, when the parameter regarding the ash deposition state in the lower part of the convection heat transfer chamber 14 becomes equal to or greater than the threshold value, the pressure wave path control unit 60 opens the valves 46B1, 47B2 corresponding to the movable nozzle 38B2, and closes the other valves 46A1, 46A2, 47A1 to 47A3, 47B1.

[0042] In S104, the movable nozzle control unit 61 moves the tip of the movable nozzle 38 corresponding to the position where the parameter regarding the ash deposition state becomes equal to or greater than the threshold value (preferably, the movable nozzle 38 closest to the position where the parameter regarding the ash deposition state becomes equal to or greater than the threshold value) toward the position where the parameter regarding the ash deposition state becomes equal to or greater than the threshold value. The movable nozzle control unit 61 moves the tip of the movable nozzle 38 corresponding to the position where the parameter regarding the ash deposition state becomes equal to or greater than the threshold value near the position where the parameter regarding the ash deposition state becomes equal to or greater than the threshold value, and adjusts the position and orientation of the tip of the movable nozzle 38 so that the tip of the nozzle 38 faces the position. Note that the tip of the movable nozzle 38 means the outlet of the pressure wave in the movable nozzle 38, that is, the nozzle port that emits the pressure wave in the movable nozzle 38. Further, the vicinity of the position where the parameter regarding the ash deposition state becomes equal to or greater than the threshold value means a range close to the position to such an extent that at least a part of the ash at the position can be removed by the emission of the pressure wave.

[0043] In addition, in S104, if, as shown in FIG. 9, a pressure wave is emitted with the tip of the movable nozzle 38 facing the central side in the flow path width direction of the convective heat transfer chamber, the ash separated from the heat transfer tube 32 may accumulate on the heat transfer tube 32 on the lower side in the gravitational direction, and starting from there, the ash may grow and block the gap between the heat transfer tubes 32. For this reason, in S104, as shown in FIG. 10, by controlling the position and orientation of the tip of the movable nozzle 38 so as to emit a pressure wave with the tip of the movable nozzle 38 facing the wall side in the flow path width direction of the convective heat transfer chamber 14, the separated ash falls through the gap between the heat transfer bank 30 and the wall of the convective heat transfer chamber, so that blockage of the gap between the heat transfer tubes 32 as described above can be suppressed.

[0044] Further, as shown in FIG. 11, when a plurality of fins 64 are provided along the exhaust gas flow direction so as to intersect the heat transfer tube 32, the movable nozzle control unit 61 may control the position and orientation of the movable nozzle 38 so that the tip of the movable nozzle 38 faces in a direction (preferably perpendicular) intersecting each of the length direction of the heat transfer tube 32 and the exhaust gas flow direction.

[0045] In the case of the finned heat transfer tube 32, in addition to blockage, it is important to ensure the heat transfer area. Therefore, by emitting a pressure wave with the tip of the movable nozzle 38 facing in a direction intersecting each of the length direction of the heat transfer tube 32 and the exhaust gas flow direction so as to drop the ash deposited not only in the flow path width direction but also in the exhaust gas flow direction (especially the ash straddling the fins adjacent in the exhaust gas flow direction), the ash deposited in the exhaust gas flow direction can be removed and the heat transfer area can be maintained.

[0046] In S105, the pressure wave control unit 62 generates a pressure wave from the pressure wave generator 36 connected to the movable nozzle 38 moved in S104, and discharges the pressure wave from the movable nozzle 38. When using any one of the movable nozzles 38A1 to 38A3 in FIG. 1, the pressure wave control unit 62 operates the pressure wave generator 36A, and when using any one of the movable nozzles 38B1 and 38B2, the pressure wave control unit 62 operates the pressure wave generator 36B. As the position where the parameter regarding the ash deposition state becomes equal to or greater than the threshold value is upstream in the exhaust gas flow direction, the pressure wave control unit 62 may perform control such as strengthening the pressure wave generated from the pressure wave generator 36 and / or increasing the generation frequency of the pressure wave.

[0047] In S106, it is determined again using the monitoring device 40 whether or not the parameter regarding the ash deposition state is less than the threshold value. When it is determined in S106 that the parameter regarding the ash deposition state is not less than the threshold value, S105 is executed again. When it is determined in S106 that the parameter regarding the ash deposition state is less than the threshold value, in S107, the pressure wave control unit 62 determines that the ash at the target position has been appropriately removed and stops the operation of the pressure wave generator 36, and the movable nozzle control unit 61 stores the movable nozzle 38 that discharged the pressure wave in S105.

[0048] In the above control flow, after S106, based on the determination result of S106, the relationship between the pressure wave emission pattern (the operation method of shock pulses) in S104 and S105 and the case where the above parameters regarding the ash deposition state in S106 are determined to be less than the threshold value may be learned by machine learning, and the learning result may be fed back to the pressure wave emission pattern in S104 and S105. Here, the pressure wave emission pattern may include at least one of, for example, the generation frequency of the pressure wave, the intensity of the pressure wave, and the direction of the tip of the movable nozzle 38 that emits the pressure wave (the direction in which the pressure wave is emitted), or may include all of these. Further, based on the learning result of the above machine learning, the threshold values used in each of S102 and S106 may be changed. Further, for example, when measuring the ash deposition thickness at each position of the heat transfer tube using an optical fiber thermometer 56 or the like, the ash deposition thickness measured by the optical fiber thermometer 56 and the position corresponding to the deposition thickness may be included in the parameters learned by the above machine learning.

[0049] According to the ash removal system 6 shown above, by controlling the position and direction of the tip of each of the plurality of movable nozzles 38A1 to 38A3, 38B1, 38B2 based on the ash deposition state of the heat transfer tubes (the heat transfer tubes 28 of the water wall 26, the heat transfer tubes 28 of the water wall 27, and the heat transfer tubes 32 of the heat transfer bank 30) at each of a plurality of positions in the boiler 4, the ash can be efficiently removed based on the ash deposition state of the above heat transfer tubes at each of a plurality of positions in the boiler 4. Thereby, the unevenness in the ash deposition amount at a plurality of positions in the boiler 4 can be suppressed, and the decrease in the heat exchange efficiency of the boiler 4 can be suppressed. Further, since the position and direction of the tip of each of the plurality of movable nozzles 38A1 to 38A3, 38B1, 38B2 can be controlled to emit the pressure wave at an appropriate position, an increase in the number of pressure wave generators 36 can be suppressed.

[0050] In addition, in the stoker-type incinerator 8, since the fuel used contains a large amount of alkali metals and heavy metals, the sintering rate of ash is faster than that of coal, and the melting point temperature is lower. Therefore, ash is more likely to adhere to and melt on the heat transfer tubes 32 of the heat transfer bank 30 in the boiler 4 and the heat transfer tubes 28 of the water walls 26 and 27 compared to a coal-fired boiler. For this reason, the ash removal system 6 that can efficiently remove ash can be preferably applied.

[0051] Also, among the plurality of movable nozzles 38A1 to 38A3, 38B1, 38B2, the movable nozzle 38 that emits a pressure wave can be selected by opening and closing the valves 46A1, 46A2, 46B1, 46B2, 47A1, 47A2, 47A3, 47B1, 47B2. Therefore, an appropriate movable nozzle 38 can be selected from the plurality of movable nozzles 38A1 to 38A3, 38B1, 38B2 with a simple configuration to emit a pressure wave.

[0052] Also, the adhesion force of ash in the boiler 4 tends to increase toward the high-temperature side, i.e., the upstream side, in the boiler 4. For this reason, by making the distance between the pressure wave generator 36A and the pressure wave inlet of the movable nozzle 38A1 smaller than the distance between the pressure wave generator 36A and the pressure wave inlet of the movable nozzle 38A3 as described above, the attenuation of the pressure wave between the pressure wave generator 36A and the movable nozzle 38A1 can be made smaller than the attenuation of the pressure wave between the pressure wave generator 36A and the movable nozzle 38A3. Thereby, the pressure wave emitted from the movable nozzle 38A1 corresponding to the high-temperature side (upstream side) in the boiler 4 can be made stronger than the pressure wave emitted from the movable nozzle 38A3 corresponding to the low-temperature side (downstream side) in the boiler 4, and the ash in the boiler 4 can be efficiently removed according to the adhesion force.

[0053] Also, for the same reason, by making the distance between the pressure wave generator 36B and the inlet of the pressure wave of the movable nozzle 38B1 smaller than the distance between the pressure wave generator 36B and the inlet of the pressure wave of the movable nozzle 38B2, the ash adhering to the heat transfer tubes in the boiler 4 can be efficiently removed according to the adhesive force. Also, for the same reason, by making the distance between the pressure wave generator 36A and the first radiation chamber 10 smaller than the distance between the pressure wave generator 36A and the convection heat transfer chamber 14, the ash adhering to the heat transfer tubes in the boiler 4 can be efficiently removed according to the adhesive force. Also, for the same reason, by making the distance between the pressure wave generator 36B and the second radiation chamber 12 smaller than the distance between the pressure wave generator 36B and the convection heat transfer chamber 14, the ash adhering to the heat transfer tubes in the boiler 4 can be efficiently removed according to the adhesive force.

[0054] Also, by discharging a pressure wave at a position where the parameter regarding the ash deposition state is equal to or higher than the threshold value, the ash at the position where the ash deposition thickness has reached a certain level or higher can be efficiently removed, suppressing the unevenness of the ash deposition amount at a plurality of positions in the boiler 4, and suppressing the decrease in the heat exchange efficiency of the boiler 4.

[0055] Also, when the parameter regarding the ash deposition state becomes less than the threshold value due to the discharge of the pressure wave from the movable nozzle 38, by stopping the operation of the pressure wave generator 36 that supplied the pressure wave to the movable nozzle 38, it is possible to suppress the excessive discharge of the pressure wave, thereby suppressing an increase in the burden on the heat transfer tubes and suppressing an increase in the operation cost of the pressure wave generator 36.

[0056] FIG. 12 is a diagram showing a schematic configuration of a boiler system 2 according to another embodiment. In the boiler system 2 shown in FIG. 12, components having the same reference numerals as those of the boiler system 2 shown in FIG. 1 represent the same configurations as those of the boiler system 2 shown in FIG. 1 unless otherwise specified, and the description thereof is omitted.

[0057] In the configuration shown in FIG. 12, the ash removal system 6 includes a rail 65 for moving the pressure wave generator 36A and a rail 66 for moving the pressure wave generator 36B, which is different from the configuration shown in FIG. 1. Also, the configuration for connecting the pressure wave generator 36A to the movable nozzles 38A1 to 38A3 and the configuration for connecting the pressure wave generator 36B to the movable nozzles 38B1 and 38B2 are different from the configuration shown in FIG. 1.

[0058] In the configuration shown in FIG. 12, the pressure wave generator 36A is configured to move on the rail 65 and is configured to be dockable to each of the plurality of movable nozzles 38A1 to 38A3. By moving on the rail 65, the pressure wave generator 36A is configured to switch the movable nozzle 38 (38A1, 38A2, or 38A3) to be docked among the plurality of movable nozzles 38A1 to 38A3.

[0059] In the configuration shown in FIG. 12, the pressure wave generator 36B is configured to move on the rail 66 and is configured to be dockable to each of the plurality of movable nozzles 38B1 and 38B2. By moving on the rail 66, the pressure wave generator 36B is configured to switch the movable nozzle 38 (38B1 or 38B2) to be docked among the plurality of movable nozzles 38B1 and 38B2.

[0060] The function of the control device 42 shown in FIG. 12 is basically the same as the configuration of the control device 42 shown in FIGS. 6 and 7, but the control flow of the control device 42 is partially different from the control flow shown in FIG. 8.

[0061] FIG. 13 is a diagram showing an example of the control flow by the control device 42 shown in FIG. 12. Since S201, S202, S204 to S207 are the same as S101, S102, S104 to S107 (including the content of machine learning after S106 above), the description is omitted. In the control flow shown in FIG. 12, the content of S203 is different from S103.

[0062] In S202, when, for at least one position among a plurality of positions in the boiler 4 monitored in S201, the parameter related to the ash deposition state is equal to or greater than the threshold value, in S203, the pressure wave generator 36A or 36B corresponding to the movable nozzle 38 (preferably, the movable nozzle 38 closest to the position where the parameter related to the ash deposition state is equal to or greater than the threshold value) corresponding to the position where the parameter related to the ash deposition state has become equal to or greater than the threshold value is docked to the movable nozzle 38. Each of the valves 47A1 to 47A3, 47B1, 47B2 may be in an always-open state, or only the valve 47 corresponding to the movable nozzle 38 docked to the pressure wave generator 36 may be opened.

[0063] In FIG. 12, for example, when the parameter related to the ash deposition state becomes equal to or greater than the threshold value at a position in the first radiant chamber 10, the pressure wave path control unit 60 docks the pressure wave generator 36A to the movable nozzle 38A1 and opens the valve 47A1 corresponding to the movable nozzle 38A1.

[0064] In FIG. 12, for example, when the parameter related to the ash deposition state becomes equal to or greater than the threshold value at the upper part in the second radiant chamber 12, the pressure wave path control unit 60 docks the pressure wave generator 36A to the movable nozzle 38A2 and opens the valve 47A2 corresponding to the movable nozzle 38A2.

[0065] In FIG. 1, for example, when the parameter related to the ash deposition state becomes equal to or greater than the threshold value at the lower part in the second radiant chamber 12, the pressure wave path control unit 60 docks the pressure wave generator 36B to the movable nozzle 38B1 and opens the valve 47B1 corresponding to the movable nozzle 38B1.

[0066] In FIG. 12, for example, when the parameter related to the ash deposition state becomes equal to or greater than the threshold value at the upper part in the convective heat transfer chamber 14, the pressure wave path control unit 60 docks the pressure wave generator 36A to the movable nozzle 38A3 and opens the valve 47A3 corresponding to the movable nozzle 38A3.

[0067] In FIG. 12, for example, when the parameter regarding the ash deposition state in the lower part of the convection heat transfer chamber 14 becomes equal to or higher than the threshold value, the pressure wave path control unit 60 docks the pressure wave generator 36B to the movable nozzle 38B2 and opens the valve 47B2 corresponding to the movable nozzle 38B2.

[0068] According to the ash removal system 6 described with reference to FIGS. 12 and 13, based on the ash deposition states of the heat transfer tubes (the heat transfer tubes 28 of the water wall 26, the heat transfer tubes 28 of the water wall 27, and the heat transfer tubes 32 of the heat transfer bank 30) at each of a plurality of positions in the boiler 4, by controlling the positions and directions of the tips of the plurality of movable nozzles 38A1 to 38A3, 38B1, 38B2, the ash can be efficiently removed based on the ash deposition states of the above heat transfer tubes at each of a plurality of positions in the boiler 4. Thereby, the unevenness in the ash deposition amount at a plurality of positions in the boiler 4 can be suppressed, and the decrease in the heat exchange efficiency of the boiler 4 can be suppressed. Further, since the positions and directions of the tips of the plurality of movable nozzles 38A1 to 38A3, 38B1, 38B2 can be controlled to emit pressure waves at appropriate positions, an increase in the number of the pressure wave generators 36 can be suppressed.

[0069] Also, by moving the pressure wave generator 36 and switching the docking target movable nozzle 38, the number of the pressure wave generators 36 can be reduced as compared with the case where the same number of pressure wave generators 36 as the movable nozzles 38 are provided. Further, as compared with the configuration shown in FIG. 1, the path for transmitting the pressure wave from the pressure wave generator 36 to the movable nozzle 38 is simplified, and the number of valves can be reduced.

[0070] The present disclosure is not limited to the above-described embodiments, and includes forms obtained by modifying the above-described embodiments and forms obtained by appropriately combining these forms.

[0071] For example, in each of the above-described embodiments, the positions and orientations of the tips of the plurality of movable nozzles 38A1 to 38A3, 38B1, 38B2 are controlled based on the ash deposition states of the heat transfer tubes (the heat transfer tubes 28 of the water-cooled wall 26, the heat transfer tubes 28 of the water-cooled wall 27, and the heat transfer tubes 32 of the heat transfer bank 30) at each of a plurality of positions in the boiler 4. However, for example, only either the position or the orientation of the tip of each of the plurality of movable nozzles 38A1 to 38A3, 38B1, 38B2 may be controlled based on the ash deposition state of the heat transfer tubes at each of a plurality of positions in the boiler 4. That is, controlling at least one of the positions and orientations of the tips of the plurality of movable nozzles 38A1 to 38A3, 38B1, 38B2 based on the ash deposition state of the heat transfer tubes at each of a plurality of positions in the boiler 4 is included in the present disclosure.

[0072] Also, for example, in the configuration shown in FIG. 12, the rails 65, 66 are shown as an example of the moving unit for moving the pressure wave generator 36. However, the moving unit is not limited to the rails 65, 66. For example, as shown in FIG. 14, a movable base 67 (a cart on which the pressure wave generator 36 is placed in the illustrated example) for moving the pressure wave generator 36 may be used. In this case, the control device 42 may execute the control flow described with reference to FIG. 13 in the same manner.

[0073] Also, for example, in each of FIGS. 1 and 12, a configuration in which one pressure wave generator 36 is provided at each of the upper and lower portions of the boiler 4 is illustrated. However, the pressure wave generator 36 may be provided only at either the upper or lower portion of the boiler 4, or two or more pressure wave generators 36 may be provided at one or both of the upper and lower portions of the boiler 4.

[0074] Also, for example, as shown in FIG. 15, when a plurality of fins 64 are provided on the heat transfer tube 32 so as to intersect the heat transfer tube 32 (when the heat transfer tube 32 is a finned tube), and when the monitoring device 40 includes the visible camera 51 and the scale 52, the scale 52 may be provided along the fins 64. In the finned heat transfer tube 32, since ash is expected to accumulate from the fins 64, the scale 52 may preferably be fixed to the fins 64, provided in the vicinity of the fins 64, or may be a ruled line written on the fins 64. Thereby, in the finned heat transfer tube 32 where ash is likely to accumulate, it becomes possible to appropriately grasp the ash accumulation state using the scale 52 and the visible camera 51.

[0075] Also, for example, as shown in FIG. 16, when a plurality of fins 64 are provided on the heat transfer tube 32 so as to intersect the heat transfer tube 32, and when the monitoring device 40 includes the laser displacement meter 55, the laser displacement meter 55 may be configured to irradiate a laser along the length direction of the heat transfer tube 32 at a position higher than the upper ends 64e of the plurality of fins 64. Thereby, in the finned heat transfer tube 32 where ash is likely to accumulate, it becomes possible to appropriately grasp the ash accumulation state using the laser displacement meter 55.

[0076] Also, for example, as shown in FIG. 17, when a plurality of fins 64 are provided on the heat transfer tube 32 so as to intersect the heat transfer tube 32, and a notch 64a is provided at a position on the same straight line L1 in each of the plurality of fins 64, and when the monitoring device 40 includes the optical fiber thermometer 56, at least a part of the optical fiber thermometer 56 may be provided along the length direction of the heat transfer tube 32 at the position of the notch 64a (inside the notch 64) of each of the plurality of fins 64. Thereby, in the finned heat transfer tube 32 where ash is likely to accumulate, it becomes possible to appropriately grasp the ash accumulation state using the optical fiber thermometer 56.

[0077] The content described in each of the above embodiments is understood as follows, for example.

[0078] (1) The ash removal system (e.g., the above-described ash removal system 6) according to at least one embodiment of the present disclosure is an ash removal system for removing ash deposited on a heat transfer tube group (e.g., the above-described heat transfer tube group 35) provided in a boiler (e.g., the above-described boiler 4), at least one pressure wave generator (e.g., the above-described pressure wave generators 36A, 36B) for generating a pressure wave, at least one movable nozzle (e.g., the above-described movable nozzles 38A1 to 38A3, 38B1, 38B2) configured to be movable within the boiler and discharge the pressure wave generated by the at least one pressure wave generator, a monitoring device (e.g., the above-described monitoring device 40) for monitoring the deposition state of ash deposited on the heat transfer tubes of the heat transfer tube group at each of a plurality of positions within the boiler, a control device (e.g., the above-described control device 42) configured to control at least one of the position and orientation of the tip of each of the at least one movable nozzle based on the deposition state monitored by the monitoring device, and includes.

[0079] According to the ash removal system described in (1) above, by controlling at least one of the position and orientation of the tip of each movable nozzle based on the deposition state of ash on the heat transfer tubes at each of a plurality of positions within the boiler, ash can be efficiently removed based on the deposition state of ash on the heat transfer tubes at each of the plurality of positions. Thereby, unevenness in the amount of ash deposition at a plurality of positions within the boiler can be suppressed, and a decrease in the heat exchange efficiency of the boiler can be suppressed. In addition, since the position and orientation of the tip of each of the at least one movable nozzle can be controlled to discharge the pressure wave at an appropriate position, an increase in the number of pressure wave generators can be suppressed.

[0080] (2) In some embodiments, in the ash removal system described in (1) above, the at least one movable nozzle includes a plurality of movable nozzles (e.g., the above-described movable nozzles 38A1 to 38A3, 38B1, 38B2) for discharging the pressure wave generated by the at least one pressure wave generator, The control device is configured to control at least one of the position and orientation of the tip of each of the plurality of movable nozzles based on the deposition state monitored by the monitoring device.

[0081] According to the ash removal system described in (2) above, by controlling at least one of the position and orientation of the tip of each of the movable nozzles based on the ash deposition state at each of a plurality of positions in the boiler, ash can be efficiently removed based on the ash deposition state at each of the plurality of positions. Thereby, unevenness in the amount of ash deposition at a plurality of positions in the boiler can be suppressed, and a decrease in the heat exchange efficiency of the boiler can be suppressed. In addition, since the position and orientation of the tip of each of the plurality of movable nozzles can be controlled to emit a pressure wave at an appropriate position, an increase in the number of pressure wave generators can be suppressed.

[0082] (3) In some embodiments, in the ash removal system described in (2) above, the at least one pressure wave generator includes a first pressure wave generator (for example, the pressure wave generator 36A or 36B described above) for generating a pressure wave, the ash removal system includes a first pipe portion (for example, the first pipe portions 44A and 44B described above) that is connected to the first pressure wave generator and through which the pressure wave generated by the first pressure wave generator passes, and a plurality of second pipe portions (for example, the second pipe portions 45A1 to 45A3, 45B1, and 45B2 described above) that connect the first pipe portion and the plurality of movable nozzles, respectively, and valves (for example, the valves 46A1, 46A2, 46B1, 46B2, 47A1, 47A2, 47A3, 47B1, and 47B2 described above) provided in each of the plurality of second pipe portions. and is provided with

[0083] According to the ash removal system described in (3) above, the movable nozzles that emit pressure waves among the plurality of movable nozzles can be selected by opening and closing the valves. Therefore, an appropriate movable nozzle can be selected from the plurality of movable nozzles with a simple configuration to emit a pressure wave.

[0084] (4) In some embodiments, in the ash removal system described in (3) above, the plurality of movable nozzles include a first movable nozzle (for example, any one of the plurality of movable nozzles 38 described above) provided to be able to emit a pressure wave into a first space in the boiler, and a second movable nozzle (for example, a movable nozzle 38 that can emit a pressure wave into a space downstream of the first movable nozzle among the plurality of movable nozzles 38 described above) provided to be able to emit a pressure wave into a second space downstream of the first space in the boiler, and the distance between the first pressure wave generator and the pressure wave inlet of the first movable nozzle is smaller than the distance between the first pressure wave generator and the pressure wave inlet of the second movable nozzle.

[0085] The adhesion force of ash in the boiler tends to increase toward the high-temperature side, i.e., the upstream side, in the boiler. Therefore, by making the distance between the first pressure wave generator and the pressure wave inlet of the first movable nozzle smaller than the distance between the first pressure wave generator and the pressure wave inlet of the second movable nozzle as described in (4) above, the attenuation of the pressure wave between the first pressure wave generator and the first movable nozzle can be made smaller than the attenuation of the pressure wave between the first pressure wave generator and the second movable nozzle. Thereby, the pressure wave emitted from the first movable nozzle corresponding to the high-temperature side (upstream side) in the boiler can be made stronger than the pressure wave emitted from the second movable nozzle corresponding to the low-temperature side (downstream side) in the boiler, and ash with a strong adhesion force on the high-temperature side in the boiler can be effectively removed.

[0086] (5) In some embodiments, in the ash removal system described in (2) above, the at least one pressure wave generator includes a first pressure wave generator (for example, the pressure wave generator 36A or 36B described above) for generating a pressure wave, and the ash removal system includes a moving unit (for example, the rails 65 or 66 or the movable base 67 described above) for moving the first pressure wave generator. The pressure wave generator is configured to be dockable to each of the plurality of movable nozzles, and is configured to switch the movable nozzle to be docked among the plurality of movable nozzles by moving using the moving unit for the moving unit.

[0087] According to the ash removal system described in (5) above, the number of valves can be reduced as compared with the configuration of (3) above.

[0088] (6) In some embodiments, in the ash removal system according to any one of (1) to (5) above, The monitoring device includes a combination of a scale (for example, the scale 52 described above) and a camera (for example, the camera 51 described above), a laser displacement meter (for example, the laser displacement meter 55 described above), an optical fiber thermometer (for example, the optical fiber thermometer 56 described above), or a combination of two or more of these three types.

[0089] According to the ash removal system described in (6) above, it is possible to monitor whether or not a parameter (ash deposition thickness or heat transfer tube temperature) regarding the ash deposition thickness exceeds a threshold value at each of a plurality of positions of the heat transfer tube group.

[0090] (7) In some embodiments, in the ash removal system according to (6) above, A plurality of fins (for example, the fins 64 described above) are provided so as to intersect the heat transfer tubes of the heat transfer tube group, The monitoring device includes a camera configured to photograph the scale provided along the fin.

[0091] According to the ash removal system described in (7) above, it is possible to appropriately grasp the ash deposition state using the scale and the camera in the finned heat transfer tube where ash is likely to deposit.

[0092] (8) In some embodiments, in the ash removal system according to (6) or (7) above, A plurality of fins (for example, the above-described fin 64) are provided so as to intersect the heat transfer tubes of the heat transfer tube group. The monitoring device includes a laser displacement meter configured to irradiate a laser along the length direction of the heat transfer tube at a position higher than the upper ends of the plurality of fins.

[0093] According to the ash removal system described in the above (8), in the finned heat transfer tube where ash is likely to accumulate, it is possible to appropriately grasp the ash accumulation state by using a laser displacement meter.

[0094] (9) In some embodiments, in the ash removal system described in any one of the above (6) to (8), A plurality of fins (for example, the above-described fin 64) are provided so as to intersect the heat transfer tubes of the heat transfer tube group. Each of the plurality of fins is provided with a notch (for example, the above-described notch 64a) at a position on the same straight line (for example, the above-described straight line L1). The monitoring device includes an optical fiber thermometer provided along the length direction of the heat transfer tube at the position of the notch of each of the plurality of fins.

[0095] According to the ash removal system described in the above (9), in the finned heat transfer tube where ash is likely to accumulate, it is possible to appropriately grasp the ash accumulation state by using an optical fiber thermometer.

[0096] (10) In some embodiments, in the ash removal system described in any one of the above (1) to (9), The control device is configured to control the position and orientation of the at least one movable nozzle such that the tip of the movable nozzle that emits a pressure wave in the convective heat transfer chamber (for example, the above-described convective heat transfer chamber 14) provided in the boiler among the at least one movable nozzle faces the wall side in the flow path width direction of the convective heat transfer chamber.

[0097] If a pressure wave is emitted with the tip of the movable nozzle directed toward the center side in the flow path width direction of the convective heat transfer chamber, the detached ash may accumulate on the heat transfer tubes located on the lower side in the gravitational direction, and starting from there, the ash may grow and block the gaps between the heat transfer tubes. On the other hand, according to the ash removal system described in the above (10), by controlling the position and orientation of the tip of the movable nozzle so as to emit a pressure wave with the tip of the movable nozzle directed toward the wall side in the flow path width direction of the convective heat transfer chamber, the detached ash falls through the gap between the heat transfer bank and the wall of the convective heat transfer chamber, so that blockage of the gaps between the heat transfer tubes can be suppressed.

[0098] (11) In some embodiments, in the ash removal system according to any one of the above (1) to (9), a plurality of fins (for example, the above-described fin 64) are provided so as to intersect the heat transfer tubes of the heat transfer tube group, the plurality of fins are arranged along the flow direction of the combustion gas of the boiler, the control device is configured to control the tip of the movable nozzle that emits a pressure wave to the fin among the at least one movable nozzle to face in a direction intersecting each of the length direction of the heat transfer tube intersecting the fin and the flow direction of the combustion gas.

[0099] In the case of heat transfer tubes with fins, in addition to blockage, it is important to ensure the heat transfer area. Therefore, by emitting a pressure wave with the tip of the movable nozzle directed in a direction intersecting each of the length direction of the heat transfer tube and the flow direction of the exhaust gas as described in the above (11), the ash deposited in the flow direction of the exhaust gas (especially the ash straddling the fins adjacent in the flow direction of the exhaust gas) can be removed to maintain the heat transfer area.

[0100] (12) In some embodiments, in the ash removal system according to any one of the above (1) to (11), the monitoring device is configured to be able to monitor whether a parameter regarding the ash deposition state at each of the plurality of positions (for example, the ash deposition thickness measured by the above-described visible camera 51 or laser displacement meter 55 or the temperature of the heat transfer tube measured by the optical fiber thermometer 56) is equal to or greater than a threshold value, When the parameter related to the ash deposition state is equal to or greater than a threshold value for at least one of the plurality of positions, the control device is configured to move the tip of the movable nozzle toward the position where the parameter is equal to or greater than the threshold value.

[0101] According to the ash removal system described in the above (12), since a pressure wave can be emitted to a position where the parameter related to the ash deposition state is equal to or greater than the threshold value, the ash at the position where the parameter related to the ash deposition state is equal to or greater than the threshold value can be efficiently removed, and a decrease in the heat exchange efficiency of the boiler can be suppressed.

[0102] (13) In some embodiments, in the ash removal system described in the above (12), When the parameter related to the ash deposition state becomes less than the threshold value due to the emission of the pressure wave from the movable nozzle, the control device is configured to stop the operation of the pressure wave generator that supplied the pressure wave to the movable nozzle.

[0103] According to the ash removal system described in the above (13), since excessive emission of the pressure wave can be suppressed, an increase in the burden on the heat transfer tubes can be suppressed, and an increase in the operating cost of the pressure wave generator can be suppressed.

[0104] (14) In some embodiments, in the ash removal system according to any one of the above (1) to (13), The boiler includes a stoker-type incinerator (for example, the incinerator 8 described above).

[0105] In a stoker-type incinerator, since the fuel used contains a large amount of alkali metals and heavy metals, the ash sintering rate is faster than that of coal, and the melting point temperature is lower. Therefore, ash is more likely to adhere to and melt on the heat transfer tubes of the heat transfer bank and the furnace wall tubes in the boiler compared to a coal-fired boiler. For this reason, the ash removal system described in (14) can be preferably applied.

[0106] (15) In some embodiments, in the ash removal system described in the above (3) or (4), The boiler includes a stoker-type incinerator (e.g., the incinerator 8 described above), a radiation chamber (e.g., the first radiation chamber 10 or the second radiation chamber 12 described above) through which the exhaust gas exiting the incinerator passes, and a convective heat transfer chamber (e.g., the convective heat transfer chamber 14 described above) provided on the downstream side of the radiation chamber in the flow direction of the exhaust gas, where a heat transfer bank is arranged. The plurality of movable nozzles include a first movable nozzle (e.g., any one of the plurality of movable nozzles 38A1, 38A2, 38B1 described above) provided to be able to emit a pressure wave into the radiation chamber, and a second movable nozzle provided to be able to emit a pressure wave into the convective heat transfer chamber (e.g., any one of the plurality of movable nozzles 38A3, 38B2 described above). The distance between the first pressure wave generator and the radiation chamber is smaller than the distance between the first pressure wave generator and the convective heat transfer chamber.

[0107] The adhesion force of ash in the boiler tends to increase toward the high-temperature side, i.e., the upstream side, in the boiler. Therefore, by making the distance between the first pressure wave generator and the first radiation chamber smaller than the distance between the first pressure wave generator and the convective heat transfer chamber as described in (15) above, the attenuation of the pressure wave between the first pressure wave generator and the first movable nozzle can be made smaller than the attenuation of the pressure wave between the first pressure wave generator and the second movable nozzle. Thereby, the pressure wave emitted from the first movable nozzle corresponding to the high-temperature side (upstream side) in the boiler can be made stronger than the pressure wave emitted from the second movable nozzle corresponding to the low-temperature side (downstream side) in the boiler, and the ash with a strong adhesion force on the high-temperature side in the boiler can be effectively removed.

Explanation of Reference Numerals

[0108] 2 Boiler system 4 Boiler 6 Ash removal system 8 Incinerator 9 Exhaust gas passage 10 First radiation chamber 12 Second radiation chamber 14 Convective heat transfer chamber 16 Garbage inlet 18 Stoker 20 Garbage outlet 22, 24 Deflection part 26, 27 Water wall 28, 32 Heat transfer tubes 29, 64 Fins 30 Heat transfer bank 35 Heat transfer tube group 36(36A, 36B) Pressure wave generator 38(38A1, 38A2, 38A3, 38B1, 38B2) Movable nozzle 40 Monitoring device 42 Control device 44A, 44B First pipe section 45A1, 45A2, 45A3, 45B1, 45B2 Second pipe section 46A1, 46A2, 46B1, 46B2, 47A1, 47A2, 47A3, 47B1, 47B2 Valves 51 Visible camera 52 Scale 53 Peephole 54 Light source 55 Laser displacement meter 56 Optical fiber thermometer 60 Pressure wave path control section 61 Movable nozzle control section 62 Pressure wave control section 65, 66 Rails 67 Movable stage 72 Processor 74 RAM 76 ROM 78 HDD 80 Input I / F 82 Output I / F 84 Bus

Claims

1. An ash removal system for removing ash deposited on a heat transfer tube group provided in a boiler, comprising: at least one pressure wave generator for generating a pressure wave; at least one movable nozzle configured to be movable within the boiler and to discharge the pressure wave generated by the at least one pressure wave generator; a monitoring device for monitoring the deposition state of ash deposited on the heat transfer tubes of the heat transfer tube group for each of a plurality of positions within the boiler; a control device configured to control at least one of the position and orientation of the tip of each of the at least one movable nozzles based on the deposition state monitored by the monitoring device; An ash removal system comprising the above components.

2. The at least one movable nozzle includes a plurality of movable nozzles for discharging the pressure wave generated by the at least one pressure wave generator, The control device is configured to control at least one of the position and orientation of the tip of each of the plurality of movable nozzles based on the deposition state monitored by the monitoring device. The ash removal system according to Claim 1.

3. The at least one pressure wave generator includes a first pressure wave generator for generating a pressure wave, The ash removal system includes: a first pipe section connected to the first pressure wave generator and through which the pressure wave generated by the first pressure wave generator passes; a plurality of second pipe sections respectively connecting the first pipe section and the plurality of movable nozzles; valves provided in each of the plurality of second pipe sections; The ash removal system according to Claim 2, comprising the above components.

4. The plurality of movable nozzles include: a first movable nozzle provided to be able to discharge a pressure wave into a first space within the boiler; a second movable nozzle provided to be able to discharge a pressure wave into a second space downstream of the first space within the boiler; including, The distance between the first pressure wave generator and the pressure wave inlet of the first movable nozzle is smaller than the distance between the first pressure wave generator and the pressure wave inlet of the second movable nozzle. The ash removal system according to Claim 3.

5. The at least one pressure wave generator includes a first pressure wave generator for generating a pressure wave, The ash removal system includes a moving unit for moving the first pressure wave generator. The pressure wave generator is configured to be dockable to each of the plurality of movable nozzles, and is configured to switch the movable nozzle to be docked among the plurality of movable nozzles by moving using the moving unit. The ash removal system according to claim 2.

6. The monitoring device includes a combination of a scale and a camera, a laser displacement meter, an optical fiber thermometer, or a combination of two or more of these three types. The ash removal system according to any one of claims 1 to 5.

7. A plurality of fins are provided so as to intersect the heat transfer tubes of the heat transfer tube group. The monitoring device includes a camera configured to photograph a scale provided along the fins. The ash removal system according to claim 6.

8. A plurality of fins are provided so as to intersect the heat transfer tubes of the heat transfer tube group. The monitoring device includes a laser displacement meter configured to irradiate a laser along the length direction of the heat transfer tube at a position higher than the upper ends of the plurality of fins. The ash removal system according to claim 6 or 7.

9. A plurality of fins are provided so as to intersect the heat transfer tubes of the heat transfer tube group. Each of the plurality of fins is provided with a notch at a position on the same straight line. The monitoring device includes an optical fiber thermometer provided along the length direction of the heat transfer tube at the position of each notch of the plurality of fins. The ash removal system according to any one of claims 6 to 8.

10. The control device is configured to control the position and orientation of the at least one movable nozzle such that the tip of the movable nozzle that emits a pressure wave in the convection heat transfer chamber provided in the boiler faces the wall side in the flow path width direction of the convection heat transfer chamber. The ash removal system according to any one of claims 1 to 9.

11. A plurality of fins are provided so as to intersect the heat transfer tubes of the heat transfer tube group. The plurality of fins are arranged along the flow direction of the combustion gas of the boiler. The control device is configured to control the tip of the movable nozzle that emits a pressure wave to the fins among the at least one movable nozzle to face in a direction intersecting the flow direction of the combustion gas. The ash removal system according to any one of claims 1 to 9.

12. The monitoring device is configured to be able to monitor whether a parameter regarding the ash deposition state at each of the plurality of positions is equal to or greater than a threshold value. The control device is configured to move the tip of the movable nozzle toward a position where the parameter regarding the ash deposition state is equal to or greater than the threshold value when the parameter regarding the ash deposition state is equal to or greater than the threshold value for at least one of the plurality of positions. The ash removal system according to any one of claims 1 to 11.

13. The control device is configured to stop the operation of the pressure wave generator that supplies a pressure wave to the movable nozzle when the parameter regarding the ash deposition state becomes less than the threshold value due to the release of the pressure wave from the movable nozzle. The ash removal system according to claim 12.

14. The boiler includes a stoker-type incinerator. The ash removal system according to any one of claims 1 to 13.

15. The boiler includes a stoker-type incinerator, a radiation chamber through which the exhaust gas exiting the incinerator passes, a convective heat transfer chamber provided downstream of the radiation chamber in the flow direction of the exhaust gas and in which a heat transfer bank is arranged, and includes The plurality of movable nozzles include a first movable nozzle provided to be able to release a pressure wave into the radiation chamber, and a second movable nozzle provided to be able to release a pressure wave into the convective heat transfer chamber, and include The distance between the first pressure wave generator and the radiation chamber is smaller than the distance between the first pressure wave generator and the convective heat transfer chamber. The ash removal system according to claim 3 or 4.

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