JP6286771B2 - Rotary tool system, heat transfer tube removal method, and heat transfer tube replacement method - Google Patents

Description

  The present invention relates to a rotary tool system for removing a plurality of heat transfer tubes connected to a tubular header from the header, a method for removing the heat transfer tube, and a method for replacing the heat transfer tube.

  For example, a flue gas treatment device used for exhaust gas treatment from a coal-fired boiler of a thermal power plant is provided with a heat exchanger that recovers heat from the exhaust gas or raises the exhaust gas temperature using the recovered heat. It has been. The heat exchanger is composed of a heat exchanger that functions as a heat recovery unit and a heat exchanger that functions as a reheating unit, both of which have a tube bundle configured to accommodate a plurality of heat transfer tubes in a casing. doing.

As a heat transfer tube, in order to increase heat transfer efficiency, a fin tube having fins formed on the outer periphery of the tube has been conventionally practiced.
The fin tubes of the heat exchanger that functions as a heat recovery unit are clogged and worn by fly ash and worn by shot cleaning. Therefore, check the pipes and replace or replace them as necessary. It is. Moreover, when the exhausted heat transfer tube reaches a large number, the tube bundle is replaced (for example, see Patent Document 1).

  As described in Patent Document 1, when the entire tube bundle is replaced, the heat transfer tube can be easily and surely updated, but the replacement cost is high, so that the implementation is difficult. Therefore, as described in Patent Document 2, a method is also known in which only the heat transfer tube is extracted and components other than the heat transfer tube are reused. The method described in Patent Document 2 is a method in which a pulling arrow is driven into the inside of the heat transfer tube, and then the pulling arrow is pulled out using a jack device or the like.

JP 2012-241964 A Japanese Patent No. 4182385

  However, in the method described in Patent Document 2, the heat transfer tube fixing hole, that is, the header is generated by generating a shear stress between the heat transfer tube fixing hole for fixing the heat transfer tube and the heat transfer tube. Is damaged, making it difficult to reuse the header.

  An object of this invention is to provide the rotary tool system which can remove a heat transfer tube, without damaging a header, the removal method of a heat transfer tube, and the replacement | exchange method of a heat transfer tube.

  According to a first aspect of the present invention, a rotary tool system is a rotary tool system for removing a plurality of heat transfer tubes arranged in a line in the extending direction of a tubular header and connected to the header from the header. A first hole formed in the header and connected to the plurality of heat transfer tubes, and a second hole formed in the header and aligned with a position symmetrical to the first hole. And a base plate having a third hole that is supported by the other second holes on both sides of the second hole corresponding to any one of the plurality of heat transfer tubes, and whose axis coincides with the second hole, Driven by a machine tool fixed to the base plate, the rotation axis coincides with the axis of the third hole and can be inserted into the third hole, and the tip of the rotation tool is coaxial with the rotation tool. And relative rotation is possible Provided, having a guide roller to be inserted into the one heat transfer tube.

  According to such a configuration, the rotary tool and the first hole to which the heat transfer tube is connected can be fixed through the base plate so as to be coaxial, and the guide roller rotatably supports the tip side of the rotary tool. Therefore, the axis of the rotary tool and the heat transfer tube can be accurately aligned. Thereby, the heat transfer tube can be cut without damaging the header. Thereby, the heat transfer tube can be removed.

  The rotary tool system may include a fixing jig that is attached to the other second hole and has a base plate attachment surface that is a flat surface orthogonal to the axis.

  According to such a configuration, since the base plate is supported in close contact with the base plate mounting surface of the fixing jig, the positional accuracy of the rotary tool fixed to the base plate can be increased.

  In the rotary tool system, the guide roller may be provided with a mark portion for confirming an insertion amount of the rotary tool in the axial direction.

  According to such a configuration, since the insertion amount of the rotary tool can be confirmed by the mark portion, only a desired processing range can be processed.

  According to the second aspect of the present invention, the method for removing a heat transfer tube comprises arranging a plurality of heat transfer tubes arranged in a tubular header side by side in the extending direction of the header and connected to the header. The heat transfer tube is removed from the first hole formed in the header and connected to the plurality of heat transfer tubes, and the axis coincides with a position formed in the header and symmetrical with the first hole. The second hole provided on the opposite side of the second hole corresponding to any one of the plurality of heat transfer tubes, and the second hole and the axis coincide with each other. A base plate attaching step of attaching a base plate having three holes, a machine tool fixing step of fixing a machine tool having a rotary tool to the base plate, a tip of the rotary tool, coaxial with the rotary tool, and While inserting the guide roller provided to be paired rotate in the heat transfer tube, having a first machining step of machining the connecting part between the between the heat transfer tube first hole by the rotary tool.

  According to such a configuration, the rotary tool and the first hole to which the heat transfer tube is connected can be fixed through the base plate so as to be coaxial, and the guide roller rotatably supports the tip side of the rotary tool. Therefore, the axis of the rotary tool and the heat transfer tube can be accurately aligned. As a result, the heat transfer tube can be cut without damaging the header, and the heat transfer tube can be removed.

  In the heat transfer tube removing method, a second machining step of machining the inner periphery of the heat transfer tube in the first hole by the rotary tool inserted into the first hole from the outside of the header. It is good also as a structure to have.

  According to such a structure, since not only the connection part of a heat exchanger tube and a 1st hole but a heat exchanger tube can be thinned over the whole, removal of a heat exchanger tube can be made easy.

  According to the third aspect of the present invention, the heat transfer tube replacement method includes a heat transfer tube insertion step of inserting the heat transfer tube into the first hole after any one of the heat transfer tube removal methods described above. A heat transfer tube expanding step in which a tool inserted through the second hole is brought into contact with an inner periphery of the heat transfer tube and plastically deformed so that a part of the heat transfer tube expands, and the heat transfer And a sealing step for sealing between the tube and the first hole.

  According to the present invention, the rotary tool and the first hole to which the heat transfer tube is connected can be fixed through the base plate so as to be coaxial, and the guide roller rotatably supports the tip side of the rotary tool. The axis of the rotary tool and the heat transfer tube can be accurately aligned. As a result, the heat transfer tube can be cut without damaging the header, and the heat transfer tube can be removed.

1 is a schematic configuration diagram of a thermal power plant according to an embodiment of the present invention. It is a schematic perspective view of the heat exchanger of embodiment of this invention. It is a schematic perspective view of the tube bundle of embodiment of this invention. It is sectional drawing which shows the structure of the heat exchanger tube and header of embodiment of this invention. It is a disassembled perspective view explaining the structure of the rotary tool system of embodiment of this invention. It is a perspective view of the base plate of the embodiment of the present invention. 1 is a schematic configuration diagram of a machine tool according to an embodiment of the present invention. It is a figure explaining the effect | action of the rotary tool system of embodiment of this invention, and is a figure explaining the 1st machining process which machines a heat-transfer tube from the header inside. It is sectional drawing of the heat exchanger tube after implementing a 1st machining process. It is a figure explaining the effect | action of the rotary tool system of embodiment of this invention, and is a figure explaining the 2nd machining process which machines a heat exchanger tube from the header exterior. It is sectional drawing of the heat exchanger tube after implementing a 2nd machining process.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
The rotary tool system of the present embodiment is used for repairing a tube bundle of a heat exchanger provided in a plant such as a thermal power plant. The heat exchanger is provided in a flue gas processing apparatus used for processing exhaust gas discharged from a coal-fired boiler of a thermal power plant.
The tube bundle is an assembly in which heat transfer tubes (fin tubes) are bundled, and the rotary tool system according to the present embodiment is used when a worn heat transfer tube is removed from the header of the tube bundle. Specifically, the heat transfer tube is removed by reducing the thickness of the heat transfer tube using a rotary tool such as a drill.

First, a plant having a heat exchanger in which a tube bundle is installed will be described.
As shown in FIG. 1, the thermal power plant 50 includes a flue gas processing device 52 that processes exhaust gas G discharged from a boiler 51 that burns fuel. The boiler 51 burns fuel or the like to generate heated gas. The gas heated by the boiler 51 absorbs heat by a mechanism that converts thermal energy into electric power. The gas whose heat has been absorbed is discharged as exhaust gas G to the smoke treatment apparatus 52.

  The flue gas treatment device 52 removes nitrogen oxides (NOx), soot and sulfur oxides (SOx) contained in the exhaust gas G in the process in which the exhaust gas G discharged from the boiler 51 is released from the chimney 58. The flue gas treatment device 52 includes a heat exchanger 1 that functions as a heat recovery unit 1a, an electric dust collector 53, a desulfurization device 54, a heat exchanger 1 that functions as a reheating unit 1b, a circulation pump 55, and a circulation pipe. 56, a blower 57, and a chimney 58.

  Among these, the heat exchanger 1 including the heat recovery unit 1a and the reheating unit 1b is configured to use the heat recovered by the heat recovery unit 1a for exhaust gas temperature rise in the reheating unit 1b. The heat transfer tube 2 of the heat recovery unit 1a and the heat transfer tube 2 of the reheating unit 1b are connected via a circulation pipe 56, and heat transfer water (for example, warm water) is enclosed inside the heat transfer tube 2. Has been.

  The exhaust gas G discharged from the boiler 51 is introduced into the heat recovery section 1a of the heat exchanger 1, and heat is recovered by exchanging heat with the heat transfer water flowing through the heat transfer tubes 2 arranged inside. . The temperature of the exhaust gas G that has passed through the heat recovery unit 1a is generally 85 to 110 ° C., and for example, the dust collection capability of the electric dust collector 53 is improved.

  The exhaust gas G that has passed through the heat recovery unit 1a is introduced into the electrostatic precipitator 53 and dust is removed. The exhaust gas G that has passed through the electric dust collector 53 is introduced into the desulfurization device 54. In the desulfurization apparatus 54, sulfur oxides in the exhaust gas G are absorbed and removed by, for example, an alkali or weak alkali absorbing solution in which limestone is dissolved in a slurry form. When the desulfurization apparatus 54 uses an absorption liquid in which limestone is dissolved in a slurry, gypsum is generated as a by-product. The temperature of the exhaust gas G that has passed through the desulfurization apparatus 54 generally decreases to about 50 ° C.

  The exhaust gas G that has passed through the desulfurization device 54 is introduced into the reheating unit 1 b of the heat exchanger 1. The reheating unit 1b circulates the exhaust gas G by the recovered heat recovered by the heat recovery unit 1a in the process of circulating the heat transfer water to and from the heat recovery unit 1a through the pair of circulation pipes 56 by the circulation pump 55. Heat. Here, the temperature of the outlet exhaust gas G of the desulfurization apparatus 54 at about 50 ° C. is reheated to about 85 to 110 ° C. in the reheating unit 1 b and is released from the chimney 58 to the atmosphere. A blower 57 is provided between the reheating unit 1 b and the chimney 58.

Next, the structure of the heat exchanger 1 is demonstrated using the reheating part 1b. The heat recovery unit 1a has substantially the same configuration as the reheating unit 1b, and thus the description thereof is omitted.
As shown in FIG. 2, the heat exchanger 1 has a bundle storage duct 3 that stores a plurality of tube bundles 4 that are aggregates of heat transfer tubes 2 bundled together. The heat transfer tube 2 is arranged at a predetermined position of the heat exchanger 1 through the tube bundle 4.

  The bundle storage duct 3 is a housing of the heat exchanger 1, and a duct inlet 6 and an extension portion 7 are provided at one opening of the rectangular tube-shaped box portion 5. The duct inlet 6 is an inlet through which the exhaust gas G flows into the box portion 5 of the bundle storage duct 3. The expansion part 7 is a hollow member that connects the duct inlet 6 and the box part 5. The expansion portion 7 is a cylinder whose opening diameter increases from the duct inlet 6 toward the box portion 5.

The tube bundle 4 has a rectangular cylindrical casing 11 through which the exhaust gas G can circulate, and a plurality of heat transfer tubes 2 fixed in the casing 11 so as to extend in the longitudinal direction of the casing 11. Yes. The casing 11 is arrange | positioned without gap so that the one surface orthogonal to the distribution direction of the waste gas G in the box part 5 of the bundle storage duct 3 may be filled.
Specifically, the casings 11 of the three tube bundles 4 are arranged such that the surfaces along the longitudinal direction are in contact with each other, whereby the plurality of heat transfer tubes 2 are arranged in a planar shape.

  As shown in FIG. 3, the tube bundle 4 supplies a heat transfer water to the rectangular cylindrical casing 11, the plurality of heat transfer tubes 2 extending in the longitudinal direction of the casing 11, and the plurality of heat transfer tubes 2. It has a tubular first header 15 and a tubular second header 16 that collects heat transfer water used for heat exchange in the plurality of heat transfer tubes 2. The wall thickness of the heat transfer tube 2 is, for example, 3 mm.

  The casing 11 is a box-shaped member that covers the plurality of heat transfer tubes 2, and includes a pair of long side surfaces 17 and a pair of short side surfaces 18 that connect the long side surfaces 17 to each other in the vicinity of the ends of the plurality of heat transfer tubes 2. And a pair of opening surfaces 19 which are rectangular openings formed by the edges of the long side surface 17 and the short side surface 18. The tube bundle 4 introduces the exhaust gas G from one opening surface 19 of the pair of opening surfaces 19 and discharges the exhaust gas G from the other opening surface 19.

The plurality of heat transfer tubes 2 form a stage by a plurality of (for example, 24) heat transfer tubes 2 arranged at equal intervals so as to form a plane orthogonal to the flow direction of the exhaust gas G. A plurality (for example, 38 stages) of G is provided at equal intervals in the distribution direction of G.
The heat transfer tubes 2 adjacent to the flow direction of the exhaust gas G are arranged offset in a direction orthogonal to the flow direction of the exhaust gas G and the longitudinal direction of the heat transfer tube 2. That is, when viewed from the flow direction of the exhaust gas G, the heat transfer tubes 2 adjacent to the flow direction of the exhaust gas G are arranged so as not to overlap.

  In addition, the heat transfer tubes 2 adjacent to each other in the distribution direction are connected to each other through the U vent portion 21 at the end portion. The U vent portion 21 introduces the heat transfer water flowing into the heat transfer tube 2 closest to the opening through the first header 15 into the heat transfer tube 2 at the next stage adjacent to the flow direction of the exhaust gas G. The ends of the heat transfer tube 2 are connected to each other. In other words, the plurality of heat transfer tubes 2 include a plurality of straight portions 14 and a U vent portion 21 that connects the plurality of straight portions 14 to each other.

  The first header 15 and the second header 16 are pipe (pipe) -like members extending in a direction orthogonal to the flow direction of the exhaust gas G and the longitudinal direction of the heat transfer tube 2. The first header 15 and the second header 16 are connected to a circulation pipe 56 (see FIG. 1). That is, the heat transfer water flowing through the circulation pipe 56 is introduced into the heat transfer tube 2 of the heat exchanger 1 through the first header 15 and the second header 16.

  One end of the plurality of heat transfer tubes 2 constituting the step facing the one opening surface 19 among the plurality of steps is connected to the first header 15. One end of the plurality of heat transfer tubes 2 constituting the step facing the other opening surface 19 among the plurality of steps is connected to the second header 16. By being configured in this way, the heat transfer water flowing into the first header 15 flows into all the heat transfer tubes 2 on the stage facing one opening surface 19, and the other through the U vent portion 21. And then flows out to the second header 16.

Returning to FIG. 2, a supply pipe 23 that supplies heat transfer water to the tube bundle 4 is connected to the first header 15 of each tube bundle 4. Further, a discharge pipe 24 for discharging the heat transfer water used in the heat transfer tube 2 is connected to the second header 16 of each tube bundle 4.
The supply pipe 23 is provided with a supply valve 25, and the supply of the heat transfer water to the first header 15 can be stopped by closing the supply valve 25. The discharge pipe 24 is provided with a discharge valve 26. By closing the discharge valve 26, it is possible to prevent heat medium water flowing through the discharge pipe 24 from flowing into the second header 16.

Next, the fixing structure of the heat transfer tube 2 and the first header 15 in the tube bundle 4 and the detailed structure of the first header 15 will be described. The fixing structure between the heat transfer tube 2 and the second header 16 is the same structure.
As shown in FIG. 4, the first header 15 is formed with a plug hole 27 (second hole) for facilitating access to the inside of the heat transfer tube 2 from the outside. The plug hole 27 is formed on an extension line of the axis of the heat transfer tube 2 of the first header 15 (hereinafter referred to as the heat transfer tube central axis A). The plug hole 27 is closed by the plug 28 in the operation state of the tube bundle 4.

A heat transfer tube fixing hole 30 (first hole) for fixing the heat transfer tube 2 is formed in the first header 15. The inner diameter of the heat transfer tube fixing hole 30 is substantially equal to the outer diameter of the heat transfer tube 2 or slightly larger than the outer diameter of the heat transfer tube 2. Further, the heat transfer tube fixing hole 30 and the plug hole 27 are formed to be coaxial. That is, the plug hole 27 is formed at a position symmetrical to the heat transfer tube fixing hole 30 so that the axis of the heat transfer tube central axis A of the heat transfer tube 2 coincides with the axis.
An enlarged diameter portion 31 having an inner diameter larger than the inner diameter of the heat transfer tube fixing hole 30 is provided at a predetermined position in the axial direction of the heat transfer tube fixing hole 30. In other words, a part of the heat transfer tube fixing hole 30 in the axial direction has a larger inner diameter than the other part.

  The heat transfer tube 2 inserted into the heat transfer tube fixing hole 30 is fixed by expanding the tube by applying a force from the inside of the heat transfer tube 2 to the enlarged diameter portion 31 of the heat transfer tube fixing hole 30 with a tool such as a tube expansion device. Has been. As a result, a tube expansion portion 32 having an outer diameter larger than the outer diameter of the heat transfer tube 2 is formed at a predetermined position in the axial direction of the heat transfer tube 2.

  The end of the heat transfer tube 2 and the inner peripheral surface of the first header 15 are welded by seal welding (leakage welding). By welding the end portion of the heat transfer tube 2 and the inner peripheral surface of the first header 15 by welding, a welded portion 33 in which the heat transfer tube 2 and the first header 15 are integrated is formed. Further, the heat transfer tube 2 is melted into the first header 15 by welding, whereby the header melted portion 40 (connecting portion) is formed.

  The pitch between the heat transfer tubes 2 arranged side by side in the extending direction of the first header 15 (the vertical direction in FIG. 4) is constant. Hereinafter, the pitch between the heat transfer tubes 2 is referred to as a heat transfer tube pitch P.

Next, the rotary tool system of this embodiment will be described with reference to the drawings. The rotary tool system is used when removing the exhausted heat transfer tube 2 from the first header 15. FIG. 5 is an exploded perspective view illustrating the configuration of the rotary tool system 8 of the present embodiment. As shown in FIG. 5, the rotary tool system 8 can be attached to the plug hole 27 side, but can also be attached to the heat transfer tube 2 side, which is the opposite side (see FIG. 10).
As shown in FIG. 5, the rotary tool system 8 includes a base plate 9 fixed to the first header 15 and a machine tool 10 fixed to the base plate 9.

The base plate 9 is fixed to the first header 15 using a fixing jig 41.
The fixing jig 41 is a jig for fixing the base plate 9 to the first header 15, and is attached to the plug hole 27 of the first header 15. That is, it is attached using an existing attachment hole.
The fixing jig 41 includes a screw portion 42 and a pedestal portion 43 that are screwed into the plug hole 27 of the first header 15. The pedestal portion 43 has a base plate mounting surface 44 that is a plane orthogonal to the central axis of the screw portion 42. Since the central axis of the screw part 42 of the fixing jig 41 coincides with the heat transfer tube central axis A, the base plate mounting surface 44 is fixed to the heat transfer tube central axis A by fixing the fixing jig 41 to the plug hole 27. Orthogonal. The fixing jig 41 is formed with a screw hole 45 coaxial with the screw portion 42.

  The base plate 9 is a rectangular plate member formed of a magnetic material such as iron. As shown in FIG. 6, the base plate 9 includes two fixing holes 47 used when fixing the base plate 9 to the fixing jig 41, the guide roller 12 of the machine tool 10, and the drill portion 38 (see FIG. 7). And a plurality of drill insertion holes 48 (third holes) which are holes to be inserted. The diameter of the drill insertion hole 48 is substantially the same as or slightly larger than the plug 28 fixing hole 47.

The pitch between the plurality of drill insertion holes 48 is the same as the heat transfer tube pitch P. The pitch between the fixed hole 47 and the drill insertion hole 48 is also the same as the heat transfer tube pitch P. Thereby, by fixing the base plate 9 using the fixing hole 47, the center axis A of the heat transfer tube coincides with the center of the drill insertion hole 48. That is, the axes of the heat transfer tube fixing hole 30 and the plug hole 27 coincide with the axis of the drill insertion hole 48.
The base plate 9 is fixed to a fixing jig 41 attached to the plug hole 27 with a plate fixing bolt 49. One of the two fixing holes 47 may be a long hole. Thereby, attachment of the base plate 9 can be made easy.

Moreover, the base plate 9 can also be attached to the heat transfer tube 2 side as shown in FIG. When attaching the base plate 9 to the heat transfer tube 2 side, after cutting the exposed portion of the heat transfer tube 2, the base plate 9 is directly brought into contact with the first header 15, and the base plate 9 is fixed using the long plate fixing bolt 49. To do.
That is, the base plate 9 can be fixed to both surfaces of the first header 15 on the plug hole 27 side (external side of the tube bundle) and the heat transfer tube 2 side (internal side of the tube bundle).

Returning to FIG. 5, the machine tool 10 transmits a magnet base 34 formed of magnets, a drive unit 35 fixed to the magnet base 34, and a driving force of the drive unit 35 to an output shaft 37 (see FIG. 7). And a drill portion 38 for cutting a part of the heat transfer tube 2.
The machine tool 10 is fixed to the base plate 9 by the magnetic force of the magnet base 34. The magnetic force generated in the magnet base 34 can be arbitrarily controlled by a magnetic force control device (not shown). Thereby, positioning of the machine tool 10 can be performed easily. The fixing method of the machine tool 10 is not limited to the magnetic force. For example, the machine tool 10 may be fixed to the base plate 9 using fastening members such as bolts and nuts.

The drive unit 35 can employ a drive device such as an electric motor.
The transmission portion 36 changes the axial direction of the drive shaft of the drive portion 35 so that the center axis of the output shaft 37 (drill portion 38) is orthogonal to the base plate 9 when the machine tool 10 is attached to the base plate 9. Position. That is, by attaching the machine tool 10 to the base plate 9, the center axis of the drill portion 38 becomes parallel to the heat transfer tube center axis A. The center axis of the drill portion 38 and the heat transfer tube center axis A can be matched by adjusting the mounting position of the machine tool 10.

Further, a handle 39 is provided in the transmission portion 36. The handle 39 has a function of sending the output shaft 37 (drill portion 38) in the axial direction of the output shaft 37 by rotating the handle 39. By rotating the handle 39 with the machine tool 10 attached to the base plate 9, the drill portion 38 moves in the axial direction and is inserted into the drill insertion hole 48 of the base plate 9.
The drill part 38 is a drill that can expand the hole diameter by being inserted into an existing hole. The drill portion 38 can be inserted into the drill insertion hole 48 of the base plate 9 by being attached to the base plate 9. The drill portion 38 has a drill diameter D (see FIG. 7) that is slightly smaller than the outer diameter of the heat transfer tube 2. The drill diameter D is appropriately changed according to work.

  As shown in FIG. 7, a guide roller 12 provided coaxially with the drill unit 38 is attached to the tip of the drill unit 38 of the machine tool 10. The guide roller 12 is a cylindrical member formed of a plastic material such as POM (polyacetal resin). The guide roller 12 is attached to a connecting shaft 46 extending from the drill body via a bearing (bearing) (not shown). Thereby, the guide roller 12 can rotate relative to the drill portion 38.

Further, the outer diameter of the guide roller 12 (guide roller diameter R) is slightly smaller than the inner diameter of the heat transfer tube 2. That is, the guide roller diameter R is dimensioned such that when the drill portion 38 is moved in the axial direction, the guide roller diameter R can be inserted into the inner peripheral side of the heat transfer tube 2 and does not shake after insertion.
In addition, on the outer peripheral surface of the guide roller 12, a mark portion 29 extending over the entire circumference in the circumferential direction is printed. Details of the marking portion 29 will be described later.

(How to replace the heat transfer tube)
Next, the exchange method of the heat transfer tube 2 using the rotary tool system 8 of this embodiment is demonstrated. The exchange of the heat transfer tube 2 includes a heat transfer tube removal step for removing the heat transfer tube 2 and a heat transfer tube attachment step for attaching the heat transfer tube 2.

(Heat transfer tube removal process)
First, the heat transfer tube removal process will be described.
First, the heat medium flowing through the tube bundle 4 to which the heat transfer tube 2 to be removed is attached is stopped. Next, as shown in FIG. 8, the exposed portion of the heat transfer tube 2 to be removed is cut off from the first header 15. In the heat transfer tube removing step, the heat transfer tube 2 is thinned by cutting the inner peripheral surface of the heat transfer tube 2 from which the exposed portion has been cut off from the plug hole 27 side and the heat transfer tube 2 side. .

(Base plate installation process)
Next, the drill insertion hole 48 is positioned at the position of the plug hole 27 corresponding to the heat transfer tube 2 to be removed (the plug hole 27 having a central axis that coincides with the heat transfer tube central axis A of the heat transfer tube 2 to be removed). The base plate 9 is attached. When attaching the base plate 9, the fixing jig 41 is attached to the plug holes 27 on both sides of the plug hole 27 corresponding to the heat transfer tube 2 to be removed, and the base plate 9 is fixed to the fixing jig 41 using the plate fixing bolts 49. . The plug hole 27 for attaching the fixing jig 41 does not have to be adjacent to the plug hole 27 corresponding to the heat transfer tube 2 to be removed, and the attachment location is determined according to the number of drill insertion holes 48 formed in the base plate 9. Is done.
As a result, the base plate 9 comes into close contact with the base plate mounting surface 44 of the fixing jig 41. Since the base plate attachment surface 44 is positioned so as to be orthogonal to the heat transfer tube central axis A, the base plate 9 is attached so as to be orthogonal to the heat transfer tube central axis A.

(Machine tool fixing process)
Next, the machine tool 10 is attached to the base plate 9. Specifically, the machine tool 10 is attached to the base plate 9 so that the center axis of the drill portion 38 of the machine tool 10 and the heat transfer tube center axis A coincide with each other. Since the base plate 9 is attached so as to be orthogonal to the heat transfer tube center axis A, the machine tool 10 can be arranged so that the center axis of the drill portion 38 and the heat transfer tube center axis A coincide.

(First machining process)
FIG. 8 is a diagram for explaining a first machining process for machining the heat transfer tube 2 from the plug hole 27 side (the inner side of the first header 15 and the outer side of the tube bundle 4).
In the first machining process, first, the machine tool 10 is operated. That is, the drill part 38 is rotated. Next, by operating the handle 39, the drill portion 38 of the machine tool 10 enters the inside of the first header 15 through the drill insertion hole 48 of the base plate 9. By sending the drill portion 38 forward, the guide roller 12 of the machine tool 10 enters the inside of the heat transfer tube 2 (see FIG. 8).

  As the guide roller 12 enters the heat transfer tube 2, the drill portion 38 is centered. That is, the guide roller 12 functions as a guide when the drill portion 38 cuts the heat transfer tube 2, and the center axis of the drill portion 38 and the heat transfer tube center axis A become more coincident. Thereby, the radial shake of the drill portion 38 can be suppressed, and the inner peripheral surface of the heat transfer tube 2 can be accurately cut.

Furthermore, by sending the drill portion 38 forward, the inner peripheral surface of the heat transfer tube 2 is cut (machined) by the drill portion 38. That is, the inner peripheral surface of the heat transfer tube 2 is machined from the inside of the first header 15.
Here, the drill part 38 has a drill diameter D slightly smaller than the outer diameter of the heat transfer tube 2. For example, when the outer diameter of the heat transfer tube 2 is 40 mm, the drill diameter D is 39.9 mm.

  As shown in FIG. 9, the range G <b> 1 to be cut by the drill portion 38 in the first machining process is just before the diameter-expanded portion 31 of the heat transfer tube fixing hole 30 of the first header 15 from the inner peripheral surface of the first header 15. Up to. That is, the tip of the drill portion 38 is prevented from entering the expanded diameter portion 31. Accordingly, at least the inner peripheral surface of the heat transfer tube 2 in the vicinity of the header melted portion 40 that joins the heat transfer tube 2 and the first header 15 is machined.

The axial cutting amount can be determined based on the exposure amount of the guide roller 12. That is, the feeding may be stopped when a part of the guide roller 12 is exposed from the cut surface of the heat transfer tube 2 (the outer peripheral surface of the first header 15).
The marking part 29 is printed to make it easy to grasp the feed amount of the drill part 38. By making the axial distance L (see FIG. 7) between the marking portion 29 and the tip of the drill portion 38 equal to the dimension G2 obtained by subtracting the dimension of the range G2 to be cut from the thickness H of the first header 15. The mark 29 can be used as a guide.

  The above operation is repeated for other heat transfer tubes 2. Thereby, the heat transfer tube 2 to be removed can be machined from the inside of the first header 15.

(Second machining process)
Next, as shown in FIG. 10, the inner peripheral surface of the heat transfer tube 2 is cut from the heat transfer tube 2 side (the outer side of the first header 15 and the inner side of the tube bundle 4).
First, the base plate 9 is fixed not on the plug hole 27 side but on the heat transfer tube 2 side. The base plate 9 is fixed using longer plate fixing bolts 49.
Next, the machine tool 10 is fixed to the base plate 9, and the inner peripheral surface of the heat transfer tube 2 is cut by the drill portion 38. Here, the drill part 38 has a drill diameter D smaller than the drill diameter D of the drill part 38 used in the first machining process. For example, when the outer diameter of the heat transfer tube 2 is 40 mm, the drill diameter D is 38 mm.

By sending the drill portion 38 to the vicinity of the inner peripheral surface of the first header 15, the heat transfer tube 2 can be thinned over the entire axial direction as shown in FIG. That is, the thickness of the heat transfer tube 2 can be reduced from T1 shown in FIG. 9 to T2 shown in FIG.
At this time, since the drill diameter D is smaller than the drill diameter D of the drill portion 38 used in the first machining process, damage to the inner peripheral surface of the heat transfer tube fixing hole 30 can be prevented. .

The above operation is repeated for other heat transfer tubes 2.
And as shown in FIG. 11, the heat transfer tube 2 which became thin is removed.

(Heat transfer tube installation process)
Next, the heat transfer tube attachment process for attaching the new heat transfer tube 2 to the heat transfer tube fixing hole 30 from which the old heat transfer tube 2 has been removed will be described.
(Heat transfer tube insertion process)
First, the heat transfer tube 2 is inserted into the heat transfer tube fixing hole 30 and temporarily fixed.

(Heat transfer tube expansion process)
Next, the predetermined tube expansion device inserted through the plug hole 27 is brought into contact with the inner peripheral surface of the heat transfer tube 2 and plastically deformed so that a part of the heat transfer tube 2 expands. Thereby, the heat transfer tube 2 is fixed to the heat transfer tube fixing hole 30.
(Sealing process)
Finally, seal welding is performed so as to seal between the heat transfer tube 2 and the heat transfer tube fixing hole 30.

According to the above-described embodiment, the drill portion 38 and the heat transfer tube fixing hole 30 to which the heat transfer tube 2 is coupled can be fixed via the base plate 9 so as to be coaxial, and the guide roller 12 can be attached to the drill portion 38. Since the distal end side is rotatably supported, the drill portion 38 and the heat transfer tube center axis A can be accurately aligned.
That is, the center of the drill portion 38 can be performed using the guide roller 12. Thereby, the inner periphery of the heat transfer tube 2 can be cut without damaging the first header 15. Thereby, the heat transfer tube 2 can be removed and the first header 15 can be reused.

  Further, by fixing the base plate 9 to the first header 15 via the fixing jig 41, the base plate 9 is supported in close contact with the base plate mounting surface 44 of the fixing jig 41, so that the drill fixed to the base plate 9 is used. The positional accuracy of the part 38 (machine tool 10) can be increased.

  Moreover, since the insertion amount of the drill part 38 can be confirmed by providing the mark part 29 in the guide roller 12, only a desired processing range can be processed. That is, it is possible to prevent the drill portion 38 from being inserted too much and damage the enlarged diameter portion 31 of the heat transfer tube fixing hole 30.

  Further, by having a second machining step for machining from the outside of the first header 15, not only the header melted portion 40 between the heat transfer tube 2 and the heat transfer tube fixing hole 30, but also the heat transfer tube 2. Can be made thin throughout. Thereby, removal of the heat-transfer tube 2 can be made easy.

The embodiments of the present invention have been described in detail with reference to the drawings. However, additions, omissions, substitutions, and other modifications can be made without departing from the spirit of the present invention. Further, the present invention is not limited by the embodiments, and is limited only by the scope of the claims.
For example, in the above-described embodiment, the base plate 9 is fixed via the fixing jig 41. However, the configuration is not limited to this as long as the orthogonality between the base plate 9 and the heat transfer tube central axis A can be secured. May be directly fixed to the first header 15.

Further, the second machining process is not necessarily performed. For example, when the heat transfer tube 2 has a sufficient thickness, the thickness may be reduced over the entire axial direction of the heat transfer tube 2 in the first machining step.
Further, the marking portion 29 is not necessarily provided. For example, the insertion amount of the drill portion 38 may be determined by the feed amount, and the range G1 (see FIG. 9) is cut when the tip portion of the guide roller 12 coincides with the outer peripheral surface of the first header 15. You may set as follows.

DESCRIPTION OF SYMBOLS 1 Heat exchanger 1a Heat recovery part 1b Reheating part 2 Heat transfer tube 3 Bundle storage duct 4 Tube bundle 5 Box part 6 Duct inlet 7 Expansion part 8 Rotating tool system 9 Base plate 10 Machine tool 11 Casing 12 Guide roller 14 Linear part 15 First header (header)
16 Second header 17 Long side surface 18 Short side surface 19 Open surface 21 U vent part 23 Supply pipe 24 Discharge pipe 25 Supply valve 26 Discharge valve 27 Plug hole (second hole)
28 Plug 29 Mark 30 Heat transfer tube fixing hole (first hole)
31 Expanded portion 32 Expanded tube portion 33 Welded portion 34 Magnet base 35 Drive portion 36 Transmission portion 37 Output shaft 38 Drill portion (rotary tool)
39 Handle 40 Header penetration (connecting part)
41 Fixing jig 42 Screw part 43 Base part 44 Base plate mounting surface 45 Screw hole 46 Connecting shaft 47 Fixing hole 48 Drill insertion hole (third hole)
49 Plate fixing bolt 50 Thermal power plant 51 Boiler 52 Smoke treatment device 53 Electric dust collector 54 Desulfurization device 55 Circulation pump 56 Circulation piping 57 Blower 58 Chimney A Heat transfer tube central axis D Drill diameter G Exhaust gas P Heat transfer tube pitch R Guide roller Diameter

Claims (6)

A rotary tool system for removing a plurality of heat transfer tubes arranged in line in the extending direction of a tubular header and connected to the header from the header,
A first hole formed in the header and connected to the plurality of heat transfer tubes; a second hole formed in the header and provided at a position symmetrical to the first hole; A base plate having a third hole supported by the other second hole on both sides of the second hole corresponding to any one of the heat transfer tubes and having an axis line coincident with the second hole;
A rotary tool driven by a machine tool fixed to the base plate, the rotation axis of which coincides with the axis of the third hole, and is freely insertable into the third hole;
A rotary tool system, comprising: a guide roller provided at a tip of the rotary tool, coaxially with the rotary tool and capable of relative rotation, and inserted into the one heat transfer tube.   The rotary tool system according to claim 1, further comprising a fixing jig attached to the other second hole and having a base plate attachment surface that is a flat surface perpendicular to the axis.   The rotary tool system according to claim 1, wherein the guide roller is provided with a mark portion for confirming an insertion amount of the rotary tool in the axial direction. A method for removing a heat transfer tube, wherein a plurality of heat transfer tubes arranged in a tubular header and arranged in the extending direction of the header and connected to the header are removed from the header,
A first hole formed in the header and connected to the plurality of heat transfer tubes; a second hole formed in the header and provided at a position symmetrical to the first hole; A base plate attaching step for attaching a base plate having a third hole supported by the other second hole on both sides of the second hole corresponding to any one of the heat transfer tubes and having an axis line coincident with the second hole;
A machine tool fixing step of fixing a machine tool having a rotary tool to the base plate;
While inserting a guide roller provided at the tip of the rotary tool coaxially with the rotary tool and capable of relative rotation, the heat transfer tube and the first hole are inserted by the rotary tool. And a first machining step for machining the vicinity of the connecting portion.   5. The method according to claim 4, further comprising a second machining step of machining an inner periphery of the heat transfer tube in the first hole by the rotary tool inserted into the first hole from the outside of the header. How to remove the heat transfer tube described in 1. After the method for removing the heat transfer tube according to claim 4 or 5,
A heat transfer tube insertion step of inserting the heat transfer tube into the first hole;
A heat transfer tube expanding step in which a tool inserted through the second hole is brought into contact with the inner periphery of the heat transfer tube and plastically deformed so that a part of the heat transfer tube expands;
And a sealing step for sealing between the heat transfer tube and the first hole.

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