JP2022130857A - Cleaning device and cleaning method of heat transfer pipes - Google Patents

Abstract

To clean multiple heat transfer pipes arranged in a vertical direction efficiently.SOLUTION: A cleaning device 200 cleans heat transfer pipes 151 which extend along an X axis direction and are arranged at predetermined intervals along a Z axis direction intersecting with the X axis direction and a Y axis direction intersecting with the X axis direction and the Z axis direction. The cleaning device 200 includes: jet holes for jetting dry ice pellets to outer surfaces of the heat transfer pipes 151; and an expansion mechanism 209 capable of adjusting a position of the jet holes as seen in the Z axis direction. The jet holes are inserted into a gap between the heat transfer pipes 151 located adjacent to each other in the Y axis direction.SELECTED DRAWING: Figure 5

Description

The present disclosure relates to a cleaning device and a method for cleaning heat transfer tubes.

2. Description of the Related Art A large-sized boiler such as a boiler for power generation has a hollow, vertically installed furnace, and a plurality of burners are arranged along the circumferential direction of the furnace wall. A large-sized boiler has a flue connected vertically above the furnace, and a heat exchanger for generating steam is arranged in the flue. Then, the burner injects a mixture of fuel and air (oxidizing gas) into the furnace to form a flame and generate combustion gas that flows into the flue. A heat exchanger is installed in a region where the combustion gas flows, and superheated steam is generated by heating water or steam flowing inside the heat transfer tubes constituting the heat exchanger.

In such a boiler, ash may adhere to the surfaces (heat transfer surfaces) of the heat transfer tubes of the heat exchanger depending on the combustion conditions and the properties of the fuel used. When ash adheres to the heat transfer surface of the heat transfer tube, the heat transfer efficiency of the heat transfer tube decreases, which may cause problems such as a decrease in boiler efficiency. Therefore, it is known to remove the ash on the surfaces of the heat transfer tubes provided in the boiler (for example, Patent Document 1).

Patent Literature 1 describes a method of cleaning an object 17 to be cleaned with a dry ice blast cleaning device. An example of the object to be cleaned 17 is a group of heat exchange pipes in a furnace in a boiler room, that is, a group of heat transfer tubes of a heat exchanger installed in the boiler. A dry ice blast cleaning apparatus cleans a cleaning site by ejecting a mixed flow of fine dry ice particles as a cleaning agent and a pressurized gas flow from the tip of a nozzle.

Japanese Patent Application Laid-Open No. 2004-223410

In a boiler, depending on the combustion conditions and the properties of the fuel used, ash may adhere to the surface (heat transfer surface) of the heat transfer tube of the heat exchanger (eg, economizer, etc.) provided in the flue. This tendency often becomes a problem in boilers that use low-quality, inexpensive fuel (for example, coal such as sub-bituminous coal, which is called low-grade coal).
2. Description of the Related Art Some heat exchangers provided in a flue of a boiler have a plurality of horizontally extending heat transfer tubes arranged vertically. However, in the apparatus of Patent Document 1, no consideration is given to cleaning the heat transfer tubes that are arranged side by side in the vertical direction. For these reasons, it is desired to efficiently clean the heat transfer tubes that are arranged side by side in the vertical direction.

The present disclosure has been made in view of such circumstances, and provides a cleaning device and a heat transfer tube cleaning method capable of efficiently cleaning a plurality of heat transfer tubes arranged in a row in the vertical direction. With the goal.

In order to solve the above problems, the cleaning device and heat transfer tube cleaning method of the present disclosure employ the following means.
A cleaning device according to an aspect of the present disclosure extends along a predetermined direction, and at predetermined intervals along a vertical direction that intersects the predetermined direction and along the predetermined direction and a cross direction that intersects the vertical direction. A cleaning device for cleaning heat transfer tubes arranged side by side, comprising an injection section for injecting a sublimable substance toward the outer surface of the heat transfer tube, and an adjustment capable of adjusting the vertical position of the injection section. and a portion, wherein the injection portion is inserted from above into a gap between the heat transfer tubes adjacent to each other in the cross direction.

A heat transfer tube cleaning method according to an aspect of the present disclosure includes a vertical direction extending along a predetermined direction and intersecting the predetermined direction, and a predetermined direction along the predetermined direction and a cross direction intersecting the vertical direction. A method for cleaning heat transfer tubes arranged side by side at intervals of , comprising: an injection step of injecting a sublimable substance onto the outer surface of the heat transfer tubes by an injection part; An inserting step of inserting into a gap between the heat transfer tubes from above, and an adjusting step of adjusting a position of the injection portion in the vertical direction by an adjusting portion.

According to the present disclosure, it is possible to efficiently clean a plurality of heat transfer tubes arranged side by side in the vertical direction.

1 is a schematic configuration diagram showing a boiler according to an embodiment of the present disclosure; FIG. FIG. 2 is a schematic diagram showing steam, condensate, and water supply systems in the boiler of FIG. 1; FIG. 4 is a schematic diagram showing a method for cleaning heat transfer tubes according to an embodiment of the present disclosure; FIG. 4 is a schematic diagram showing a method for cleaning heat transfer tubes according to an embodiment of the present disclosure; 1 is a schematic front view of a heat transfer tube and cleaning device according to an embodiment of the present disclosure; FIG. FIG. 6 is a schematic plan view showing the heat transfer tube and cleaning device of FIG. 5; FIG. 6 is a schematic side view showing the heat transfer tube and cleaning device of FIG. 5; 1 is a schematic front view of a cleaning section according to an embodiment of the present disclosure; FIG. FIG. 9 is a schematic front view showing a cleaning unit according to a modification of FIG. 8; FIG. 10 is a schematic plan view of the cleaning unit of FIG. 9; FIG. 9 is a schematic front view showing a cleaning unit according to a modification of FIG. 8; FIG. 9 is a schematic front view showing the cleaning unit according to the modification of FIG. 8, showing a state in which the cleaning unit is extended; FIG. 9 is a schematic front view of the cleaning unit according to the modification of FIG. 8, showing a contracted state of the cleaning unit; FIG. 9 is a schematic front view showing a cleaning unit according to a modification of FIG. 8; FIG. 9 is a schematic front view showing a cleaning unit according to a modification of FIG. 8; 1 is a vertical cross-sectional view of a main part of a boiler according to an embodiment of the present disclosure; FIG. 4 is a graph showing the relationship between the plant operating time and the amount of heat absorbed by the heat transfer tubes according to the embodiment of the present disclosure; 4 is a graph showing the relationship between plant operating time and ash removal amount or cleaning time according to an embodiment of the present disclosure; 5 is a graph showing the relationship between the cleaning time of the heat transfer tubes and the temperature of the heat transfer tubes themselves or the temperature of the fluid flowing inside the heat transfer tubes according to the embodiment of the present disclosure. FIG. 9 is a schematic front view showing a cleaning unit according to a modification of FIG. 8; FIG. 9 is a schematic front view showing a cleaning unit according to a modification of FIG. 8; FIG. 9 is a schematic front view showing a cleaning unit according to a modification of FIG. 8;

An embodiment of a cleaning device and a heat transfer tube cleaning method according to the present disclosure will be described below with reference to the drawings.

Preferred embodiments of the present invention will be described below with reference to the accompanying drawings. It should be noted that the present invention is not limited by this embodiment, and when there are a plurality of embodiments, the present invention includes a combination of each embodiment. In the following description, "up" and "up" indicate the upper side in the vertical direction, and "down" and "lower side" indicate the lower side in the vertical direction.

FIG. 1 is a schematic configuration diagram showing the boiler of this embodiment.

The boiler 10 of the present embodiment uses pulverized coal (carbon-containing solid fuel) pulverized as pulverized fuel, burns this pulverized fuel with a burner, and heats the heat generated by this combustion with feed water and steam. It is a coal-fired (pulverized coal-fired) boiler capable of generating superheated steam.

In this embodiment, a coal-fired boiler 10 has a furnace 11, a combustion device 12, and a combustion gas passage 13, as shown in FIG. The furnace 11 has a hollow rectangular shape and is installed along the vertical direction. The furnace wall 101 constituting the furnace 11 is composed of a plurality of heat transfer tubes and fins connecting them, and heat generated by combustion of the pulverized fuel is heat-exchanged with water and steam flowing inside the heat transfer tubes, It suppresses the temperature rise of the furnace wall.

The combustion device 12 is provided on the lower side of the furnace wall that constitutes the furnace 11 . In this embodiment, the combustion device 12 has a plurality of burners (eg 21, 22, 23, 24, 25) mounted on the furnace wall. For example, the burners 21, 22, 23, 24, and 25 are arranged at equal intervals along the circumferential direction of the furnace 11 as one set, and a plurality of stages (for example, five stages in FIG. 1) are arranged along the vertical direction. are placed. However, the shape of the furnace, the number of burners in one stage, the number of stages, the arrangement, etc. are not limited to this embodiment.

The burners 21 , 22 , 23 , 24 , 25 are connected to a plurality of pulverizers (mills) 31 , 32 , 33 , 34 , 35 via pulverized coal supply pipes 26 , 27 , 28 , 29 , 30 . The pulverizers 31, 32, 33, 34, and 35 have, for example, a pulverizing table (not shown) rotatably supported in a pulverizer housing, and a plurality of pulverizing rollers (not shown) above the pulverizing table. is supported so as to be rotatable in conjunction with the rotation of the grinding table. When coal is put between a plurality of crushing rollers and a crushing table, it is crushed and conveyed to a classifier (not shown) in the crusher housing by a carrier gas (primary air, oxidizing gas). , pulverized fuel classified within a predetermined particle size range can be supplied to combustion burners 21, 22, 23, 24, 25 from pulverized coal supply pipes 26, 27, 28, 29, 30.

Further, the furnace 11 is provided with a wind box 36 at the mounting position of the burners 21, 22, 23, 24, 25, and one end of an air duct (airway) 37 is connected to the wind box 36. As shown in FIG. The air duct 37 is provided with a forced draft fan (FDF) 38 at the other end.

The combustion gas passage 13 is connected to the upper portion of the furnace 11 in the vertical direction, as shown in FIG. The combustion gas passage 13 is provided with superheaters 102, 103, 104, reheaters 105, 106, and an economizer 107 as heat exchangers for recovering the heat of the combustion gas. Heat is exchanged between the combustion gas and feed water or steam flowing through each heat exchanger.

As shown in FIG. 1, the combustion gas passage 13 is connected to the downstream side thereof with a flue 14 through which the combustion gas that has undergone heat exchange is discharged. An air heater (air preheater) 42 is provided between the flue 14 and the air duct 37 , and heat exchange is performed between the air flowing through the air duct 37 and the combustion gas flowing through the flue 14 . Combustion air supplied to 22, 23, 24, 25 can be heated.

Further, the flue 14 is provided with a denitrification device 43 at a position upstream of the air heater 42 . The denitrification device 43 supplies a reducing agent such as ammonia or urea water, which has a function of reducing nitrogen oxides, into the flue 14, and causes a reaction between the nitrogen oxides in the combustion gas to which the reducing agent is supplied and the reducing agent. is accelerated by the catalytic action of the denitration catalyst installed in the denitration device 43, thereby removing and reducing nitrogen oxides in the combustion gas.
The gas duct 41 connected to the flue 14 is provided with a dust collector 44 such as an electric dust collector, an induced draft fan (IDF) 45, a desulfurization device 46, etc. at a position downstream of the air heater 42. A chimney 50 is provided at the end.

On the other hand, when the plurality of pulverizers 31, 32, 33, 34, 35 are driven, the pulverized fuel produced is fed into the pulverized coal supply pipes 26, 27, 28, 29, 30 together with the carrier gas (primary air, oxidizing gas). to the burners 21, 22, 23, 24, 25. In addition, by exchanging heat with the exhaust gas discharged from the flue 14 by the air heater 42, the heated combustion air (secondary air, oxidizing gas) is supplied from the air duct 37 through the wind box 36 to the burner 21, 22, 23, 24, 25. The burners 21, 22, 23, 24, and 25 blow into the furnace 11 a pulverized fuel mixture in which pulverized fuel and carrier gas are mixed, and also blow combustion air into the furnace 11. At this time, the pulverized fuel mixture is ignited. By doing so, a flame can be formed. A flame is generated in the lower part of the furnace 11 , and high-temperature combustion gas rises inside the furnace 11 and is discharged to the combustion gas passage 13 . Air is used as the oxidizing gas in this embodiment. It may have a higher or lower oxygen ratio than air, and can be used by optimizing the fuel flow rate.

Further, the furnace 11 is provided with an additional air port 39 above the mounting positions of the burners 21, 22, 23, 24 and 25. As shown in FIG. An end of an additional air duct 40 branched from the air duct 37 is connected to the additional air port 39 . Therefore, the combustion air (secondary air, oxidizing gas) sent by the forced draft fan 38 is supplied from the air duct 37 to the wind box 36, from which the combustion burners 21, 22, 23, 24, 21, 22, 23, 24, . 25 and additional air for combustion delivered by forced draft fan 38 can be supplied to additional air port 39 through additional air duct 40 .

In the lower region A of the furnace 11, the pulverized fuel mixture and combustion air (secondary air, oxidizing gas) are combusted to generate flame. The inside of the furnace 11 is maintained in a reducing atmosphere by setting the amount of air supplied to be less than the theoretical amount of air with respect to the amount of pulverized coal supplied. That is, nitrogen oxides (NOx) generated by combustion of pulverized coal are reduced in the region B of the furnace 11, and then additional air for combustion (additional air) is additionally supplied from the additional air port 39, thereby reducing pulverized coal. Oxidative combustion is completed, and the amount of NOx generated by the combustion of pulverized coal is reduced.

After that, as shown in FIG. 1, the combustion gas is transferred to the second superheater 103, the third superheater 104, and the first superheater 102 (hereinafter sometimes simply referred to as superheaters) arranged in the combustion gas passage 13. ), the second reheater 106, the first reheater 105 (hereinafter sometimes simply referred to as a reheater), and the economizer 107. After that, nitrogen oxides are reduced and removed by the denitrification device 43. After the particulate matter is removed by the dust collector 44 and the sulfur oxides are removed by the desulfurization device 46, the dust is discharged from the stack 50 into the atmosphere. Note that the heat exchangers do not necessarily have to be arranged in the order described above with respect to the combustion gas flow.

Next, the superheaters 102, 103, 104, the reheaters 105, 106, and the economizer 107 provided in the combustion gas passage 13 as heat exchangers will be described in detail. FIG. 2 is a schematic diagram showing a heat exchanger provided in the coal-fired boiler 10. As shown in FIG.
Note that FIG. 1 does not accurately show the positions of the heat exchangers (superheaters 102, 103, 104, reheaters 105, 106, economizer 107) in the combustion gas passage 13. The arrangement order of the exchangers relative to the combustion gas flow is not limited to that shown in FIG.

As shown in FIG. 2, the boiler power plant 1 of the present embodiment includes heat exchangers (superheaters 102, 103, 104, reheaters 105, 106, economizer 107) provided in the coal-fired boiler 10. , a steam turbine 110 that is rotationally driven by the steam generated by the coal-fired boiler 10, and a generator 115 that is connected to the steam turbine 110 and generates power by the rotation of the steam turbine 110.

A steam turbine 110 that is rotationally driven by the steam generated by the coal-fired boiler 10 includes, for example, a high-pressure turbine 111, an intermediate-pressure turbine 112, and a low-pressure turbine 113. Steam from a reheater, which will be described later, is supplied to the intermediate-pressure turbine. After entering the low pressure turbine. A condenser 114 is connected to the low-pressure turbine 113, and the steam that rotationally drives the low-pressure turbine 113 is cooled by cooling water (eg, seawater) in the condenser 114 to become condensed water. Condenser 114 is connected to economizer 107 via water supply line L1. The water supply line L1 is provided with, for example, a condensate pump (CP) 121, a low pressure water supply heater 122, a boiler water supply pump (BFP) 123, and a high pressure water supply heater . A part of the steam that drives the steam turbines 111, 112, and 113 is extracted to the low-pressure feedwater heater 122 and the high-pressure feedwater heater 123, and is supplied to the high-pressure feedwater heater 124 and the low-pressure feedwater heater 122 via the extraction line (not shown). Feedwater supplied as a heat source and supplied to the economizer 107 is heated.

For example, a case where the coal-fired boiler 10 is a once-through boiler will be described. An economizer 107 is connected to each evaporator tube of the furnace wall 101 . The feed water heated by the economizer 107 is heated by radiation from the flame in the furnace 11 when passing through the evaporating pipes forming the furnace wall 101 and is led to the steam separator 126 . The steam separated by the steam separator 126 is supplied to the superheaters 102, 103, and 104, and the drain water separated by the steam separator 126 is sent through the steam separator drain tank and the drain water line L2. It is led to condenser 114 .

In addition, when the once-through boiler is started or during low-load operation, the feed water supplied from the economizer 107 does not evaporate completely when passing through the evaporation pipes constituting the furnace wall 101, and as a result, the steam is separated. An operating state (wet operating state) in which a water level exists in the vessel 126 may occur. In this wet operation state, the drain water separated by the steam separator 126 is joined to the middle of the water supply line L1 through the circulation line L6 using the boiler circulation pump (BCP) 128, so that the economizer 107 may be circulated and supplied to the evaporation tubes forming the furnace wall 101.

When the combustion gas flows through the combustion gas passage 13 , the combustion gas is heat-recovered by the superheaters 102 , 103 , 104 , the reheaters 105 , 106 and the economizer 107 . On the other hand, the feed water supplied from the boiler feed water pump (BFP) 123 is preheated by the economizer 107 and then heated to steam when passing through the evaporating pipes forming the furnace wall 101. be guided. The steam separated by the steam separator 126 is introduced into the superheaters 102, 103, 104 and superheated by the combustion gas. The superheated steam generated by the superheaters 102, 103, 104 is supplied to the high pressure turbine 111 via the steam line L3, and drives the high pressure turbine 111 to rotate. The steam discharged from the high-pressure turbine 111 is introduced into the reheaters 105, 106 via the steam line L4 and reheated. The re-superheated steam is supplied to the low-pressure turbine 113 through the intermediate-pressure turbine 112 via the steam line L5, and drives the intermediate-pressure turbine 112 and the low-pressure turbine 113 to rotate. The rotating shaft of each steam turbine 111, 112, 113 rotates a generator 115 to generate power. The steam discharged from the low-pressure turbine 113 is cooled by the condenser 114 to become condensed water, and is sent to the economizer 107 again through the water supply line L1.

Next, a cleaning device for cleaning the heat transfer tubes and a method for cleaning the heat transfer tubes will be described in detail.
In this embodiment, a method for cleaning the heat transfer tube panel 150 that constitutes the economizer 107 provided in the combustion gas passage 13 will be described. In the following description and drawings, the vertical direction is the Z-axis direction, the horizontal direction in which the heat transfer tubes extend is the X-axis direction, and the direction orthogonal to the Z-axis direction and the X-axis direction is the Y-axis direction. explain.

The heat transfer tube panel 150 of the economizer 107 to be cleaned in this embodiment has a plurality of heat transfer tubes 151 arranged side by side in the Z-axis direction (vertical direction), as shown in FIG. . Each heat transfer tube 151 extends along the X-axis direction (predetermined direction). The heat transfer tube panel 150 is configured in a panel shape by a plurality of heat transfer tubes 151 arranged in the Z-axis direction. In the economizer 107, a plurality of heat transfer tube panels 150 are arranged side by side along the Y-axis direction (intersecting direction). In this manner, as shown in FIG. 4 and the like, the economizer 107 has a plurality of heat transfer tubes 151 extending in the X-axis direction arranged side by side in the Y-axis direction and the Z-axis direction at predetermined intervals. .
The distance between the heat transfer tubes 151 adjacent in the Z-axis direction is approximately 100 mm to 200 mm. The heat transfer tube panel 150 has a length (height) in the Z-axis direction of about 1000 mm to 2000 mm and a length (width) in the X-axis direction of about 3000 mm to 15000 mm. The economizer 107 is provided with about 50 to 400 heat transfer tube panels 150 .

In the coal-fired boiler 10, depending on the combustion conditions and the properties of the fuel to be used, ash may accumulate on the outer surface (heat transfer surface) of the heat transfer tube 151 of the heat exchanger (for example, the economizer 107, etc.) provided in the combustion gas passage 13. A adheres and deposits (hereinafter simply referred to as "adhesion") (see FIG. 4). The ash A adhering to the heat transfer tubes 151 may adhere so as to connect the heat transfer tubes arranged in the vertical direction (hereinafter, the ash adhering so as to connect the heat transfer tubes is referred to as a “bridge portion”. ). This phenomenon is often a problem in boilers that use low quality and cheap fuels, especially low quality coals such as sub-bituminous coals (low-ratio coals). This is generally due to the fact that the melting point of ash generated by burning low-grade coal is lower than that of other coals. When the ash A adheres to the outer surface of the heat transfer tube 151, the heat transfer efficiency in heat exchange between the fluid (water supply) flowing inside the heat transfer tube 151 and the combustion exhaust gas decreases. should be cleaned regularly to remove This cleaning work is performed at the time of periodic inspection of the power plant 1 or the like.

In the cleaning work according to this embodiment, as shown in FIG. 3, the ash A adhering to the heat transfer tubes 151 is cleaned by dry ice blasting. Specifically, pellet-shaped dry ice (hereinafter referred to as “dry ice pellet D”) is sprayed with a high-pressure gas (for example, compressed air) as an injection medium, and the object (ash adhering to the heat transfer tube 151 Ash A is removed by spraying A). In the present embodiment, an example in which the dry ice pellets (sublimable substance) D have a general standard shape (cylindrical shape with a diameter of about 3 mm) will be described, but the shape of the dry ice pellets D is not limited to this. The shape of the dry ice pellets D is determined by the properties and adhesion of the ash, and may be spherical or powdery, for example.

The principle of cleaning by dry ice blasting is as follows.
First, by injecting dry ice pellets D (having a temperature of about −79° C., which is slightly lower than the sublimation temperature of carbon dioxide −78.5° C.) against the ash A adhering to the heat transfer tube 151, the ash A microcracks due to heat shrinkage (thermal shock).
The dry ice pellets D enter into this gap, the gap between the adhering ash A and the outer surface of the heat transfer tube 151, and the inside of the ash, and the entered dry ice pellet D sublimates. The dry ice pellet D expands about 750 times in volume by sublimation. As a result, the ash is separated from the outer surface of the heat transfer tube 151 .
Thus, in cleaning by dry ice blasting, ash is removed by thermal shock due to low-temperature dry ice pellets D and volumetric expansion during sublimation.

Cleaning by dry ice blasting is performed using a dry ice blasting device. Specifically, a hose (not shown) having a cleaning part 201 attached to its tip is pulled into the combustion gas passage 13 from a dry ice blast apparatus body (not shown) installed outside the combustion gas passage 13 . As shown in FIG. 4, a cleaning unit 201 (nozzle 202 and cleaning unit 201 5) is inserted from above. At this time, when the cleaning unit 201 is inserted into the gap between the heat transfer tubes 151 from below (that is, when the cleaning operation is performed from below), the ash and dry ice pellets D removed by the operator are sublimated carbon dioxide ( specific gravity is higher than that of air), it is inserted from above to avoid this. Then, dry ice pellets D are ejected from a nozzle 202 attached to the tip of the cleaning part 201 to remove the ash A adhering to the heat transfer tube 151 . Since the jetted dry ice pellets D sublimate into gas, only the ash after peeling remains after removal. Although FIG. 4 illustrates an example in which the operator directly holds the cleaning unit 201, the cleaning unit 201 may be attached to a cart 205 or the like as shown in FIG. 5 and the like.

Next, the cleaning device 200 that cleans the heat transfer tubes 151 will be described in detail.
As shown in FIGS. 5 to 7, the cleaning device 200 includes a cleaning unit 201 that injects dry ice pellets D, and a carriage (moving unit) 205 that supports the cleaning unit 201. As shown in FIG.

The cleaning part 201 is a tubular member extending in the Z-axis direction. Dry ice pellets D are supplied to the cleaning unit 201 together with a high-pressure gas as an ejection medium. The cleaning unit 201 has a nozzle 202 inserted into a gap between the heat transfer tubes 151 and a base 203 extending upward from the upper end (root) of the nozzle 202 and supported by a carriage 205 .

A plurality of injection holes (injection portions) 204 (see FIG. 8, etc.) are formed in the nozzle 202 . Dry ice pellets D are jetted from a plurality of jet holes 204 toward heat transfer tubes 151 using high-pressure gas as a jetting medium. Details of the structure of the nozzle 202 will be described later.

The base portion 203 is supported by the carriage 205 at its upper end portion (root portion). Specifically, the base 203 is supported so as to be able to swing around a central axis extending along the Y-axis direction. As a result, the cleaning part 201 can swing about the upper end of the base part 203 in the X-axis direction as indicated by the arrow A1 in FIG.

The carriage 205 includes wheels 206 placed on the upper surface of the heat transfer tube 151, a body portion 207 that is movable by the wheels 206, and a base portion 203 of the cleaning portion 201 that is fixed to the body portion 207 and supports the base portion 203 in a swingable manner. and a support portion 208 . As shown in FIGS. 6 and 7, the truck 205 is provided so as to span, for example, three heat transfer tubes 151 arranged in the Y-axis direction. The cleaning units 201 are respectively inserted into two gaps formed by the three heat transfer tubes 151 .

For example, four wheels 206 are provided as shown in FIGS. The plurality of wheels 206 are arranged two by two in the Y-axis direction and the X-axis direction. Each wheel 206 rotates around a central axis extending in the Y-axis direction. That is, the wheels 206 move in the X-axis direction by rotating. Note that the wheels 206 may be provided so as to engage with the heat transfer tubes 151 . Specifically, the wheel 206 may engage with the heat transfer tube 151 so as to restrict relative movement in the Y-axis direction.

The main body 207 includes a lower frame 207a to which the wheels 206 are attached, four pillars 207b extending upward from the upper surface of the lower frame 207a, and an upper frame 207c fixed to the upper ends of the pillars 207b. have.

The lower frame 207a is a rectangular frame. A cleaning part 201 passes through an opening formed in the center.
The upper ends of the four pillars 207b are fixed to the corners of the upper frame 207c. Each column 207b has a lower end fixed to a corner of the lower frame 207a. Each column portion 207b extends along the Z-axis direction. An extension mechanism (adjustment unit) 209 capable of adjusting the length of the column portion 207b in the Z-axis direction is provided at substantially the center of each column portion 207b in the Z-axis direction.
The upper frame 207c is a rectangular frame. Two support portions 208 extending in the Y-axis direction are fixed to the inner peripheral surface of the upper frame 207c. The two support portions 208 are arranged side by side in the X-axis direction. Each supporting portion 208 supports the cleaning portion 201 in a swingable manner (see arrow A1 in FIG. 5). The height of the upper end of the outer surface of the heat transfer tube 151 arranged on the uppermost part of the heat transfer tube panel 150 has a slight height difference along the X-axis direction, but supports the cleaning part 201 in a swingable manner. By doing so, even if there is a height difference, the cleaning part 201 always extends along the Z-axis direction. Therefore, the dry ice pellets D can be suitably jetted.

The carriage 205 can move the cleaning part 201 along the X-axis direction by moving on the heat transfer tube 151 along the X-axis direction (see arrow A2 in FIGS. 5 and 6). Note that the mechanism for moving the cleaning unit 201 along the X-axis direction is not limited to the carriage 205 . For example, a rail extending in the X-axis direction may be provided, and the rail and a slidable member may move the cleaning unit 201 along the X-axis direction. Alternatively, the cleaning unit 201 may be lifted by a wire or the like to move the cleaning unit 201 along the X-axis direction.

In addition, the extension mechanism 209 can adjust the vertical position of the cleaning unit 201 by extending and retracting. That is, the extension mechanism 209 can raise the vertical position of the cleaning unit 201 by extending. In addition, the telescopic mechanism 209 can lower the vertical position of the cleaning unit 201 by contracting. The expansion/contraction mechanism 209 may be able to set the insertion depth of the cleaning unit 201 to an integral multiple of the distance between the heat transfer tubes 151 in the Z direction. This makes it possible to set the position of the cleaning unit 201 so that the position of the injection hole 204 of the nozzle 202 corresponds to the Z-axis position of the heat transfer tube 151 .
Further, the extension mechanism 209 may be configured to extend and retract only within a predetermined operating range from a set position. By setting the operating range of the expansion mechanism 209 in the vertical direction to the same length as the gap formed between the heat transfer tubes 151 adjacent in the Z-axis direction, the dry ice pellets D can be placed in the gap between the heat transfer tubes 151. It is possible to inject repeatedly.

Next, details of the nozzle 202 will be described with reference to FIGS. 7 to 15. FIG.
As described above, nozzle 202 is formed with a plurality of injection holes 204 . As shown in FIG. 7, the plurality of injection holes 204 includes a first injection portion 204a for injecting dry ice pellets D into the heat transfer tubes 151 on one side of the heat transfer tubes adjacent in the Y-axis direction, and a first injection portion 204a on the other side. and a second injection part 204 b for injecting dry ice pellets D to the heat transfer tube 151 . By configuring in this way, it is possible to simultaneously clean the plurality of heat transfer tubes 151 arranged side by side in the Y-axis direction. Therefore, cleaning work can be made more efficient. Moreover, since the reaction force due to the injection of the dry ice pellets D is canceled, the force for holding the nozzle 202 can be reduced.

Also, as shown in FIGS. 7 and 8, the plurality of injection holes 204 are arranged side by side along the Z-axis direction. By configuring in this way, it is possible to simultaneously clean the plurality of heat transfer tubes 151 arranged side by side in the Z-axis direction. Therefore, cleaning work can be made more efficient. Also, the distance between the injection holes 204 arranged side by side in the Z-axis direction may be the same distance as the distance between the heat transfer tubes 151 arranged side by side in the Z-axis direction.
Also, the flow paths for supplying the dry ice pellets D to the plurality of injection holes 204 may be independent and different flow paths. By doing so, the dry ice pellets D can be reliably guided to each of the injection holes 204 without the dry ice pellets D being unevenly guided to any one of the injection holes 204 .

The injection holes 204 arranged side by side along the Z-axis direction may be arranged such that the first injection portion 204a and the second injection portion 204b have different heights, as shown in FIG. . Further, as shown in FIG. 8, the first injection part 204a and the second injection part 204b may be arranged so as to have the same height.

Moreover, each injection hole 204 may be formed so as to inject the dry ice pellets D outward in the radial direction, as shown in FIG. 8 and the like. By forming the injection holes 204 in this way, the moment acting on the nozzle 202 due to the injection of the dry ice pellets D can be canceled, so that the rotation of the nozzle 202 can be suppressed.

Alternatively, as shown in FIGS. 9 and 10, the dry ice pellets D may be jetted in the tangential direction of the cylindrical nozzle 202 . By forming the injection hole 204 in this way, the moment acting on the nozzle 202 causes the nozzle 202 to rotate about the center axis extending in the Z-axis direction while injecting the dry ice pellets D as indicated by the arrow A3 in FIG. 202 rotates. Therefore, the plurality of heat transfer tubes 151 arranged side by side in the Y-axis direction can be cleaned at the same time. Therefore, cleaning work can be made more efficient. Note that, in this configuration, the nozzle 202 is rotatably supported with respect to the base 203 .

Further, the injection hole 204 may be formed so as to inject the dry ice pellets D in a fan shape. By configuring in this way, the dry ice pellets D can be jetted over a wide range.
In addition, the dry ice pellets D are jetted toward the ash bridge portion and the outer surface of the heat transfer tube 151 . In the case of the heat transfer tube 151 with fins, it may be injected into the gaps between adjacent fins of the heat transfer tube 151 .

Also, the cleaning unit 201 may include a mechanical removal mechanism that removes the ash adhering to the heat transfer tubes 151 by physical action. Specifically, for example, the cleaning section 201 may include a vane section 211 attached to the lower end of the nozzle 202, as shown in FIG. The blade portion 211 has a cylindrical shaft portion 211a extending downward from the lower end of the nozzle 202, and blades 211b attached to the lower end of the shaft portion 211a and extending radially outward. The blade portion 211 rotates around a central axis extending in the Z-axis direction, as indicated by an arrow A4. When the blade portion 211 rotates, the blade 211b comes into contact with the ash attached to the heat transfer tube 151 and the bridged ash. As a result, ash adhering to the heat transfer tubes 151 and bridging ash are removed.

Note that the mechanical removal mechanism is not limited to the blade portion 211 . For example, the mechanical removal mechanism may be a piercing needle that removes the ash adhering to the heat transfer tube 151 by piercing the needle. Further, the mechanical removal mechanism may be a knocker that removes the ash adhering to the heat transfer tubes 151 by applying an impact to the heat transfer tubes 151 to vibrate the heat transfer tubes 151 . Moreover, the mechanical removal mechanism may be a sound wave generator that removes the ash by irradiating the ash adhering to the heat transfer tube 151 with sound waves.
In addition, when the cleaning unit 201 has a mechanical removal mechanism, first, after removing the ash adhering to the heat transfer tube 151 to some extent by the mechanical removal mechanism, dry ice pellets D are injected from the nozzle 202, and the heat transfer tube 151 Any remaining ash may be removed.

In addition, the cleaning part 201 may be a stretchable part that can be stretched in the longitudinal direction, as shown in FIG. 12 . In this case, the base portion 203 of the cleaning portion 201 has, for example, three cylindrical divisions 203a vertically divided, and the diameter of the three divisions 203a becomes smaller as they are disposed downward. there is As a result, as shown in FIG. 13, the split portion 203a provided below can be accommodated inside the split portion 203a provided above. Thereby, the cleaning part 201 can be contracted. Further, since the diameter of the nozzle 202 is smaller than that of the dividing portion 203a arranged at the lowest position, the nozzle 202 can be accommodated inside the dividing portion 203a provided at the lowest position. Thereby, the cleaning part 201 can be further contracted. By configuring in this way, the cleaning device 200 can be miniaturized. Thereby, even if the space for cleaning work is narrow, the cleaning device 200 can be easily brought into the room. Therefore, cleaning work can be facilitated.

Moreover, the cleaning part 201 may be provided with a flexible part 212 between the base part 203 and the nozzle 202, as shown in FIG. In this case, a guide 213 extending along the Z-axis direction is provided, and the nozzle 202 is supported by the guide 213 so as to be movable along the extending direction of the guide 213 . With this configuration, the dry ice pellets D can be ejected while moving the nozzle 202 in the Z-axis direction as indicated by an arrow A5.

Further, the cleaning part 201 may be provided with a ball connection part 215 between the base part 203 and the nozzle 202, as shown in FIG. The ball connection portion 215 supports the nozzle 202 so as to be rotatable about a central axis extending in the Z-axis direction as indicated by an arrow A6, and supports the nozzle 202 about a central axis extending in the X-axis direction as indicated by an arrow A7. rotatably supported. That is, the nozzle 202 is supported so as to be able to swing.
In this case, the nozzle 202 may be formed so that the central axis is curved with respect to the Z-axis direction. Even if the nozzle 202 is curved, by swinging the nozzle 202 , the nozzle 202 can be inserted into the gap between the heat transfer tubes 151 without interfering with the heat transfer tubes 151 .

Next, a method for cleaning the heat transfer tubes 151 of the economizer 107 using the cleaning device 200 will be described.
First, the operation of the coal-fired boiler 10 is stopped, and safety measures such as isolation measures and ventilation are taken to make it possible to enter the boiler 10 . Next, a worker enters the flue 14 of the coal-fired boiler 10 and installs the cleaning device 200 on the heat transfer tube 151 of the economizer 107 (see FIGS. 5 to 7). Next, the cleaning part 201 is inserted into the gap formed between the heat transfer tubes 151 adjacent in the Y-axis direction (insertion step). Then, the extension mechanism 209 is adjusted so that the injection hole 204 formed in the nozzle 202 of the cleaning unit 201 is at a predetermined position in the Z-axis direction (adjustment step). After setting the position of the injection hole 204 in the Z-axis direction to a predetermined position, the dry ice pellets D are injected from the injection hole 204 (injection step). Thus, the heat transfer tubes 151 are cleaned.

In addition, as shown in FIG. 16, a collecting plate 160 for collecting the removed ash may be installed below the economizer 107 before the dry ice pellets D are injected from the injection hole 204 .
Below the economizer 107, a hopper 161 for collecting fly ash generated during normal operation of the coal-fired boiler 10 is provided. A discharge port 162 is formed at the bottom of the hopper 161 . The fly ash collected by the hopper 161 is discharged out of the system by the transfer pipe 163 connected to the discharge port 162 and the pump 164 provided in the transfer pipe 163 .

On the other hand, the ash removed from the heat transfer tubes 151 at the time of cleaning the heat transfer tubes 151 includes ash that has been peeled off while remaining in a lump, and is generally larger than fly ash. Therefore, if the ash is to be discharged through the discharge port 162, the transfer pipe 163, etc., the discharge port 162 and the transfer pipe 163 may be clogged. Therefore, when cleaning the heat transfer tube 151, before the dry ice pellets D are injected from the injection hole 204, a collection plate (collection part) 160 may be installed so as to cover the hopper 161 from above. . By providing the collection plate 160, the ash A removed from the heat transfer tube 151 is collected by the collection plate 160 (collection step). As a result, clogging of the discharge port 162 and the transfer pipe 163 can be prevented.

The ash collected by the collecting plate 160 is carried out from the manhole 165 formed in the flue 14 . After carrying out the ash from the manhole 165, the weight of the carried out ash is measured (measurement step). And a control part judges the condition of cleaning based on the weight of the ash measured by the measurement process (judgment process).
For example, the control unit may determine the cleaning status based on a graph showing the relationship between the operation time of the power plant 1 and the appropriate amount of ash removed (ash removal amount), as shown in FIG. 18 . The solid line graph in FIG. 18 indicates an appropriate amount of ash removal according to the operation time of the power plant 1 based on actual results. When the amount of removed ash is approximately the same as the amount of the solid line graph in FIG. 18, the control unit determines that the ash adhering to the heat transfer tube 151 has been sufficiently removed by cleaning. On the other hand, when the amount of removed ash does not reach the amount indicated by the solid line graph in FIG. 18 (for example, when the amount indicated by the dashed line in FIG. 18) It is determined that the adhering ash has not been sufficiently removed.
Incidentally, the weight measurement may be performed for each area by dividing the collecting portion into predetermined areas on the XY plane. This makes it possible to grasp the cleaning status of the heat transfer tube 151 corresponding to each area (positioned above each area in the Z-axis direction).

The control unit includes, for example, a CPU (Central Processing Unit), a RAM (Random Access Memory), a ROM (Read Only Memory), a computer-readable storage medium, and the like. A series of processes for realizing various functions is stored in a storage medium or the like in the form of a program, for example, and the CPU reads out this program to a RAM or the like, and executes information processing and arithmetic processing. As a result, various functions are realized. The program may be pre-installed in a ROM or other storage medium, provided in a state stored in a computer-readable storage medium, or delivered via wired or wireless communication means. etc. may be applied. Computer-readable storage media include magnetic disks, magneto-optical disks, CD-ROMs, DVD-ROMs, semiconductor memories, and the like.

Note that the control unit may determine the cleaning status based on other than the amount of ash to be removed (ash removal amount). For example, as shown in FIG. 18, the control unit may determine the cleaning status based on the cleaning time corresponding to the operating time of the plant.
Further, for example, the control unit may determine the cleaning status based on the amount of heat absorbed by the heat transfer tubes 151 . As shown in FIG. 17 , the amount of heat absorbed by the heat transfer tubes 151 decreases with the operating time of the power plant 1 . This is because as the power plant 1 operates, ash adheres to the outer surface of the heat transfer tube 151 and the heat transfer efficiency decreases. When the heat transfer tube 151 is cleaned at the timing t1, the ash on the outer surface of the heat transfer tube 151 is removed, so the heat absorption amount of the heat transfer tube 151 increases (recovers). At this time, if the heat transfer tubes 151 are normally cleaned, the heat absorption amount of the heat transfer tubes 151 is sufficiently recovered as indicated by the solid line. On the other hand, if the cleaning is insufficient, the amount of heat absorbed by the heat transfer tubes 151 is not sufficiently recovered, as indicated by the dashed line. By detecting the amount of heat absorbed by the heat transfer tube 151 in this manner, the cleaning status can be determined. Based on the data accumulated in this way, as shown in FIG. 18, it is possible to grasp the degree of cleaning required for the operation time of the power plant 1 (amount of ash removed, cleaning time, etc.). .

In addition, the control unit responds to changes in the temperature (metal temperature) of the heat transfer tube 151 itself due to direct contact of the dry ice pellets D with the outer surface of the heat transfer tube 151 or changes in the temperature of the fluid flowing inside the heat transfer tube 151. You may judge the situation of cleaning based on. As shown in FIG. 19, the temperature of the heat transfer tube 151 itself or the temperature of the fluid inside the heat transfer tube 151 decreases according to the cleaning time. This is because the low-temperature dry ice pellets D cool the heat transfer tubes 151 during cleaning. At this time, if ash does not adhere to the outer peripheral surface of the heat transfer tube 151, the heat transfer efficiency of the heat transfer tube 151 is high. The temperature of the heat transfer tube 151 itself or the temperature of the fluid inside the heat transfer tube 151 decreases. On the other hand, if the cleaning is insufficient and ash adheres to the outer peripheral surface of the heat transfer tube 151, the heat transfer efficiency of the heat transfer tube 151 is low. , the temperature of the heat transfer tube 151 itself or the temperature of the fluid inside the heat transfer tube 151 decreases. Thus, the change in the temperature of the heat transfer tube 151 itself or the change in the temperature of the fluid inside the heat transfer tube 151 differs depending on the cleaning conditions. Therefore, the cleaning status can be determined by detecting the temperature change.

Further, the cleaning device 200 includes a deposit detection unit that detects deposits (ash, etc.) attached to the outer surface of the heat transfer tube 151, and the cleaning status is determined based on the detection result of the deposit detection unit. good. In this case, a control section is provided for determining the progress of cleaning based on the detection result of the adhering matter detection section. Thereby, the progress of cleaning can be grasped.
The adhering matter detection unit is, for example, a plurality of laser pointers 220 (irradiators) provided in the cleaning unit 201, as shown in FIG. A plurality of laser pointers 220 are arranged side by side at predetermined intervals in the Z-axis direction. Also, the laser pointer 220 is arranged so that the height position is the position of the gap formed between the heat transfer tubes 151 adjacent to each other in the Z-axis direction. The laser pointer 220 irradiates a laser in the Y-axis direction as indicated by an arrow L. When the ash A exists in the laser irradiation target (the gap formed between the heat transfer tubes 151 adjacent in the Z-axis direction), the ash A blocks the laser L. On the other hand, when the ash A does not exist in the irradiation destination of the laser L, the laser L is not blocked by the ash A. Therefore, since the laser L is transmitted through the gap, the laser L can be visually recognized from a predetermined place. The state of cleaning can be determined from the state of the irradiated laser. In addition, the irradiation object from an irradiation device is not limited to a laser beam. Light having a certain illuminance may be used, or weak radio waves may be used. Further, the detection position is not limited to the transmission side, and the reflection may be detected from the irradiation side. In this case, it is determined that the ash A has not been removed when the reflection is detected.

Also, the adhering substance detection unit is, for example, a plurality of ultrasonic probes 221 provided in the cleaning unit 201 as shown in FIG. The plurality of ultrasonic probes 221 are arranged side by side at predetermined intervals in the Z-axis direction. Also, the ultrasonic probe 221 is arranged so that the height position is the position of the gap formed between the heat transfer tubes 151 adjacent to each other in the Z-axis direction. The ultrasonic probe 221 transmits ultrasonic waves in the Y-axis direction as indicated by an arrow S. When ash A exists in the destination of the ultrasonic wave (the gap formed between the heat transfer tubes 151 adjacent in the Z-axis direction), the ash A relatively quickly reflects the ultrasonic wave S and returns. come. On the other hand, when the ash A does not exist at the destination of the ultrasonic wave S, the ash A does not reflect the ultrasonic wave S, so that the ultrasonic wave S does not return, or if it returns, it returns relatively late. The status of cleaning can be determined from the state of the ultrasonic waves transmitted in this manner.

Also, the cleaning status may be determined from an image captured by the camera 222 provided in the cleaning unit 201 . Specifically, as shown in FIG. 22 , cameras are provided in the cleaning unit 201 so as to be arranged vertically (in the Z-axis direction) at predetermined intervals. Each camera 222 photographs a predetermined area of the heat transfer tube panel 150 . For example, the camera 222 provided at the top photographs the area B1. Also, the camera 222 provided at the bottom takes an image of the area B2. In the captured image, the area of the heat transfer tube 151 and the area of the ash A are specified by image diagnosis. The control unit determines the cleaning status based on the captured image. For example, the control unit determines that the cleaning is finished when the area ratio of the area of the heat transfer tube 151 and the area of the ash A in the photographed image satisfies a specified value. Image diagnosis may be performed using AI or the like by performing machine learning by accumulating photographed images and corresponding cleaning conditions in association with each other.

According to this embodiment, the following effects are obtained.
In this embodiment, the injection holes 204 for injecting the dry ice pellets D toward the outer surface of the heat transfer tube 151 are provided. As a result, the accretion (ash A) adhering to the outer surface of the heat transfer tube 151 can be removed by the collision force when the dry ice pellets D collide with the adhering matter adhering to the outer surface of the heat transfer tube 151 . In addition, the dry ice pellets D enter the gap between the deposit and the surface of the heat transfer tube 151, and the dry ice pellet D sublimates in the gap and expands in volume, thereby peeling off the deposit from the surface of the heat transfer tube 151. can be removed.
Moreover, since the dry ice pellets D sublimate into gas, they do not remain after being injected from the injection hole 204 . Therefore, compared to the cleaning method using water or organic matter, there is no need to discharge the substances used for cleaning, so the cleaning work can be facilitated and shortened.

In addition, in this embodiment, an extension mechanism 209 is provided that can adjust the position of the injection hole 204 in the vertical direction. Therefore, the vertical positions of the injection holes 204 can be adjusted according to the vertical distance between the heat transfer tubes 151 (hereinafter referred to as "pitch of the heat transfer tubes 151"). Therefore, when cleaning the heat transfer tubes 151 arranged vertically at predetermined intervals, after cleaning one heat transfer tube 151, the injection hole 204 is vertically moved by the extension mechanism 209. Thus, the injection hole 204 can be easily moved to the cleaning position of the next heat transfer tube 151 . Therefore, it is possible to efficiently clean the plurality of heat transfer tubes 151 arranged side by side at predetermined intervals in the vertical direction.

Further, by adjusting the vertical position of the injection hole 204 by the extension mechanism 209, the vertical position of the injection hole 204 can be set to a desired position. As a result, the injection hole 204 can be adjusted to a position where the adhering substances can be removed accurately, so that the adhering substances can be preferably removed.

Further, in this embodiment, the nozzle 202 is inserted from above into the gap between the heat transfer tubes 151 adjacent in the cross direction. As a result, even the heat transfer tubes 151 arranged relatively densely in the cross direction can be suitably cleaned.

In this embodiment, low-temperature dry ice pellets D are jetted. As a result, the object to be cleaned (the heat transfer tube 151) is cooled by the dry ice pellets D and thermally shrinks, so that the adhering substances are peeled off. Therefore, deposits can be removed favorably.

In this embodiment, a carriage 205 is provided to move the injection holes 204 along a predetermined direction (extending direction of the heat transfer tubes 151). Therefore, the carriage 205 can move the injection holes 204 along the extending direction of the heat transfer tubes 151 . Therefore, the heat transfer tubes 151 can be easily cleaned along the extending direction.

It should be noted that the present disclosure is not limited to the inventions according to the above-described embodiments, and modifications can be made as appropriate without departing from the scope of the present disclosure.
For example, in the above-described embodiment, the boiler of the present disclosure is a coal-fired boiler, but the fuel used is biomass fuel, PC (petroleum coke) fuel generated during oil refining, and solid fuel such as petroleum residue. It may be a boiler that In addition, the fuel is not limited to solid fuels, and petroleum products such as heavy oil, light oil, and heavy oil, and liquid fuels such as factory waste liquids can also be used. ) can also be used. Furthermore, it can also be applied to a mixed firing boiler that uses a combination of these fuels.

Further, for example, in the above-described embodiment, an example of cleaning the economizer 107 with the cleaning device 200 has been described, but the present disclosure is not limited to this. For example, the cleaning device 200 may clean the superheaters 102 , 103 , 104 and the reheaters 105 , 106 .

In addition, parameters used for cleaning (e.g., target part, cleaning time, amount of dry ice used, amount of ash removal) and heat absorption change data before and after cleaning are accumulated, and parts, timing, and degree of cleaning required to be cleaned are predicted and planned. You can

The cleaning device and the method for cleaning the heat transfer tubes 151 described in the above-described embodiments are grasped, for example, as follows.
A cleaning device according to an aspect of the present disclosure extends along a predetermined direction (X-axis direction), extends in a vertical direction (Z-axis direction) intersecting the predetermined direction (X-axis direction), and extends in the predetermined direction (X-axis direction). A cleaning device (200) for cleaning the heat transfer tubes (151) arranged at predetermined intervals along the cross direction (Y-axis direction) intersecting the vertical direction (Z-axis direction) and the vertical direction (Z-axis direction). There is an injection part (204) for injecting the sublimable substance (D) toward the outer surface of the heat transfer tube (151), and the position of the injection part (204) in the vertical direction (Z-axis direction) is adjusted. an adjustable part (209), and the injection part (204) is inserted from above into the gap between the heat transfer tubes (151) adjacent to each other in the cross direction (Y-axis direction).

The above configuration includes an injection section that injects the sublimable substance toward the outer surface of the heat transfer tube. This makes it possible to remove the deposits adhering to the outer surface of the heat transfer tube by the collision force when the sublimable substance collides with the deposits adhering to the outer surface of the heat transfer tube. In addition, the sublimable substance enters the gap between the adhering substance and the surface of the heat transfer tube, and the sublimable substance sublimates in the gap and expands in volume. Deposits can be removed.
Also, since the sublimable substance sublimates into gas, it does not remain after being injected from the injection part. Therefore, compared to the cleaning method using water or organic matter, there is no need to discharge the substances used for cleaning, so the cleaning work can be facilitated and shortened.
In addition, the above configuration includes an adjustment section that can adjust the position of the injection section in the vertical direction. Therefore, the vertical position of the injection section can be adjusted according to the vertical separation distance between the heat transfer tubes. Therefore, when cleaning the heat transfer tubes that are arranged vertically at predetermined intervals, after cleaning one heat transfer tube, the adjustment section moves the injection section in the vertical direction so that the next The injection part can be easily moved to the cleaning position of the heat transfer tube. Therefore, it is possible to efficiently clean the plurality of heat transfer tubes arranged side by side at predetermined intervals in the vertical direction.
Further, by adjusting the vertical position of the injection section by the adjusting section, the vertical position of the injection section can be set to a desired position. As a result, the ejector can be adjusted to a position where the adhering matter can be removed accurately, so that the adhering matter can be preferably removed.
Further, in the above configuration, the injection part is inserted from above into the gap between the heat transfer tubes adjacent in the cross direction. As a result, even the heat transfer tubes, which are relatively densely arranged in the cross direction, can be suitably cleaned.

Further, in the cleaning device according to one aspect of the present disclosure, the sublimable substance (D) is dry ice pellets.

In the above configuration, low-temperature dry ice pellets are jetted. As a result, the object to be cleaned is cooled and thermally shrunk by the dry ice pellets, so that the adhering substances are peeled off. Therefore, deposits can be removed favorably.

Further, the cleaning device according to one aspect of the present disclosure includes a moving section (205) that moves the injection section (204) along the predetermined direction (X-axis direction).

The above configuration includes a moving section that moves the injection section along a predetermined direction (extending direction of the heat transfer tube). Therefore, the moving part can move the injection part along the extending direction of the heat transfer tube. Therefore, the heat transfer tubes can be easily cleaned along the extending direction.

Further, in the cleaning device according to an aspect of the present disclosure, a plurality of the injection parts (204) are provided, and the plurality of the injection parts (204) are adjacent to the heat transfer tubes ( 151) A first injection part (204) for injecting the sublimable substance (D) to the heat transfer tube (151) on one side of each other, and the sublimation to the heat transfer tube (151) on the other side and a second injection part (204) for injecting the substance (D).

In the above configuration, the plurality of injection units include a first injection unit that injects the sublimable substance into the heat transfer tube on one side of the heat transfer tubes that are adjacent in the cross direction, and a sublimable substance into the heat transfer tube on the other side. and a second injection unit that injects the Thereby, a plurality of heat transfer tubes arranged side by side in the cross direction can be cleaned at the same time. Therefore, cleaning work can be made more efficient.

Further, in the cleaning device according to an aspect of the present disclosure, a plurality of the injection units (204) are provided, and the plurality of injection units (204) are arranged side by side along the vertical direction (Z-axis direction). ing.

In the above configuration, the plurality of injection portions are arranged side by side in the vertical direction. Thereby, a plurality of heat transfer tubes arranged in the vertical direction can be cleaned at the same time. Therefore, cleaning work can be made more efficient.

Further, the cleaning device according to one aspect of the present disclosure includes a telescopic portion (203a) that can be telescopically extended in the longitudinal direction.

In the above configuration, the cleaning device can be downsized by contracting the expandable portion. As a result, even if the space for cleaning work is narrow, the cleaning device can be easily brought into the room. Therefore, cleaning work can be simplified.

In addition, the cleaning device according to an aspect of the present disclosure includes an attached matter detection unit (220, 221, 222) that detects an attached matter attached to the surface of the heat transfer tube (151), the attached matter detection unit (220, 221, 222), and a control unit that determines the cleaning status based on the detection results of the cleaning apparatus 221 and 222).

The above configuration includes a control section that determines the progress of cleaning based on the detection result of the adhering matter detection section. Thereby, the progress of cleaning can be grasped.

Further, a heat transfer tube cleaning method according to an aspect of the present disclosure includes a vertical direction (Z-axis direction) that extends along a predetermined direction (X-axis direction) and intersects with the predetermined direction (X-axis direction), and , a method for cleaning heat transfer tubes (151) arranged side by side at predetermined intervals along an intersecting direction (Y-axis direction) intersecting the predetermined direction (X-axis direction) and the vertical direction (Z-axis direction) an injection step of injecting the sublimable substance (D) onto the outer surface of the heat transfer tube (151) by the injection part (204); an inserting step of inserting from above into the gap between the heat transfer tubes (151), an adjusting step of adjusting the position of the injection portion (204) in the vertical direction (Z-axis direction) by an adjusting portion (209); Prepare.

Further, a method for cleaning a heat transfer tube according to an aspect of the present disclosure includes a collecting step of collecting deposits removed from the outer surface of the heat transfer tube (151) in the jetting step; and a determination step of determining the progress of cleaning based on the weight of the attached matter measured in the measuring step.

The above configuration includes a judgment step for judging the progress of cleaning based on the weight of the collected deposits. Thereby, the progress of cleaning can be grasped.

1: Power plant 10: Coal-fired boiler 11: Furnace 12: Combustion device 13: Combustion gas passage 14: Flue 17: Object to be cleaned 21: Burner 26: Pulverized coal supply pipe 31: Pulverizer 36: Wind box 37: Air Duct 38 : forced draft fan 39 : additional air port 40 : additional air duct 41 : gas duct 42 : air heater 43 : denitration device 44 : dust collector 46 : desulfurization device 50 : chimney 101 : furnace wall 102 : first superheater 103 : 2nd superheater 104 : 3rd superheater 105 : 1st reheater 106 : 2nd reheater 107 : Economizer 111 : High pressure steam turbine 112 : Medium pressure steam turbine 113 : Low pressure steam turbine 114 : Condenser 121: Condensate pump 122: Low pressure feed water heater 123: Boiler feed water pump 124: High pressure feed water heater 126: Brackish water separator 127: Brackish water separator drain tank 128: Boiler circulation pump 115: Generator 150: Heat transfer tube panel 151: Heat transfer tube 160 : Collection plate 161 : Hopper 162 : Discharge port 163 : Transfer pipe 164 : Pump 165 : Manhole 200 : Cleaning device 201 : Cleaning unit 202 : Nozzle 203 : Base 203a : Split unit 204 : Injection hole (injection unit)
205: Cart (moving part)
206: wheel 207: main body 207a: lower frame 207b: column 207c: upper frame 208: support 209: expansion mechanism (adjustment unit)
211: Blade portion 211a: Shaft portion 211b: Blade 213: Guide 215: Ball connecting portion 220: Laser pointer (irradiator)
221: Ultrasonic probe 222: Camera L1: Water supply line L2: Drain water line L3: Steam line L4: Steam line L5: Steam line L6: Circulation line

Claims (9)

Cleaning the heat transfer tubes extending along a predetermined direction and arranged side by side at predetermined intervals in a vertical direction intersecting with the predetermined direction and in a cross direction intersecting the predetermined direction and the vertical direction. A cleaning device,
an injection unit that injects a sublimable substance toward the outer surface of the heat transfer tube;
an adjustment unit capable of adjusting the position of the injection unit in the vertical direction,
The cleaning device, wherein the injection part is inserted from above into a gap between the heat transfer tubes adjacent to each other in the cross direction. 2. The cleaning device of claim 1, wherein the sublimable material is dry ice pellets. 3. The cleaning device according to claim 1, further comprising a moving part that moves the injection part along the predetermined direction. A plurality of the injection units are provided,
The plurality of injection parts include a first injection part for injecting the sublimable substance to the heat transfer tube on one side of the heat transfer tubes adjacent to each other in the cross direction, and a first injection part for injecting the sublimable substance to the heat transfer tube on the other side 4. The cleaning device according to any one of claims 1 to 3, further comprising a second injection section for injecting a sublimable substance. A plurality of the injection units are provided,
The cleaning device according to any one of claims 1 to 4, wherein the plurality of jetting portions are arranged side by side along the vertical direction. 6. The cleaning device according to any one of claims 1 to 5, comprising a telescopic part that can be telescopically extended in the longitudinal direction. an adhering matter detection unit that detects an adhering matter adhering to the surface of the heat transfer tube;
7. The cleaning device according to any one of claims 1 to 6, further comprising a control section that determines the cleaning status based on the detection result of the adhering matter detection section. A cleaning method for heat transfer tubes extending along a predetermined direction and arranged side by side at predetermined intervals in a vertical direction intersecting with the predetermined direction and in a crossing direction intersecting the predetermined direction and the vertical direction. and
an injection step of injecting a sublimable substance onto the outer surface of the heat transfer tube by an injection unit;
an inserting step of inserting the injection part from above into a gap between the heat transfer tubes adjacent to each other in the cross direction;
A method for cleaning a heat transfer tube, comprising: an adjustment step of adjusting the vertical position of the injection unit by an adjustment unit. a collecting step of collecting deposits removed from the outer surface of the heat transfer tube by the injection step;
a measuring step of measuring the weight of the deposit collected in the collecting step;
9. The method of cleaning a heat transfer tube according to claim 8, further comprising a determination step of determining progress of cleaning based on the weight of the deposit measured in the measurement step.

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