JP6291886B2 - Heat transfer tube replacement method - Google Patents

Description

  The present invention relates to a heat transfer tube replacement method in a multi-tube heat exchanger used in a heat transfer tube of a heat exchanger, particularly a condenser of a boiler turbine power generation facility.

  Conventionally, in a boiler turbine power generation facility installed in a factory facility such as a steel mill, for example, steam generated in the boiler is used to generate power with a turbine generator, and the generated power is supplied to the factory facility and used in the factory facility. Supplying steam for process. The steam exhausted from the turbine is cooled in the condenser and supplied to the boiler again.

  Generally, a multi-tube heat exchanger called a so-called shell and tube in which a plurality of tubes (heat transfer tubes) are provided inside a cylindrical body is used as a condenser. In such a multi-tube heat exchanger, a hole may be formed in the heat transfer tube due to deterioration over time, corrosion, abnormal overheating, or the like.

  When a hole breaks in the heat transfer tube of the condenser, the cooling water flowing inside the heat transfer tube leaks and contaminates the steam flowing inside the fuselage. For this reason, usually, measures are taken to prevent outflow and inflow between two fluids by closing the end of the heat transfer tube in which a broken hole has occurred with a stopper (for example, Patent Document 1).

  Since the cooling water does not flow inside the closed heat transfer tube and the heat transfer action of the heat transfer tube is lost, the heat transfer area is reduced and the heat exchange performance is deteriorated. Therefore, when designing a multi-tube heat exchanger such as a condenser, the heat transfer area is determined in consideration of a margin rate in consideration of closure by a plug in advance.

Japanese Patent Laid-Open No. 2000-213890

  In the above-described multitubular heat exchanger, if a number of holes are formed in the heat transfer tubes more than expected, a desired heat exchange performance cannot be obtained. In such a case, the heat transfer tube is exchanged. Usually, the heat transfer tube is inserted into a plate-like member called a tube plate provided with a plurality of holes and fixed in the body. Therefore, when replacing the heat transfer tubes, all the heat transfer tubes are replaced together with the tube sheets. Therefore, a heat transfer tube in which deterioration over time and corrosion hardly progress and a broken hole does not occur, that is, a heat transfer tube that can still be used, is replaced. As a result, the maintenance cost becomes high.

From the viewpoint of reducing the replacement cost of the heat transfer tube, it is preferable to replace only the heat transfer tube in which the hole has been broken. In other words, the heat transfer tube is formed of a thin-walled tube to improve the heat transfer rate during heat exchange, so it is not strong in strength and is prone to breakage. Since it is mixed, it is not necessary to replace all the heat transfer tubes when a broken hole is generated in an arbitrary heat transfer tube, and as described above, this can be dealt with by plugging the heat transfer tube in which the broken hole is formed. On the other hand, since the tube plate for fixing the heat transfer tube is formed thick, it is strong in strength and has a long life compared to the heat transfer tube. Therefore, the present inventor can maintain the maintenance cost by replacing only the heat transfer tube in which the hole has been broken even if the predetermined number of heat transfer tubes has been broken and the desired heat exchange performance can not be obtained. Was thought to be reduced.

  However, in a large heat exchanger such as a condenser, the distance between the tube plates is about several meters, while the heat transfer tube has a diameter of about several tens of millimeters. Therefore, the tube plate hole and the end of the new heat transfer tube are bent due to the bending that occurs in the heat transfer tube even if an attempt is made to insert a new heat transfer tube from the hole in the tube plate after extracting the heat transfer tube in which a broken hole has occurred from inside the fuselage. Is extremely difficult to align. For this reason, it is not easy to replace only the heat transfer tube in which the hole is broken.

  The present invention has been made in view of such a point, and by replacing the heat transfer tubes of the multi-tube heat exchanger individually, it is possible to avoid replacing all the heat transfer tubes together with the tube sheet, and to reduce the maintenance cost. The purpose is to reduce.

  In order to achieve the above object, the present invention includes a tube plate provided oppositely, a plurality of straight tubular heat transfer tubes inserted through holes formed in the tube plate, the tube plate, and the heat transfer tube. A multi-tube heat exchanger having a body that accommodates the heat transfer tube, wherein the heat transfer tube is replaced through a connection jig at one end of the heat transfer tube inserted through the hole in the tube plate. The heat transfer tube is connected by connecting a heat transfer tube for replacement, and applying either a pushing or pulling force along the axial direction of the heat transfer tube to at least one of the heat transfer tube or the replacement heat transfer tube. As a guide, the replacement heat transfer tube is moved to a position where it is mounted on the tube plate.

  According to the present invention, since the heat transfer tube and the replacement heat transfer tube are connected via the connection jig, the heat transfer tube and the replacement heat transfer tube can be formed into an integral straight tube. Then, a force such as pushing and pulling is applied to the connected heat transfer tube or replacement heat transfer tube along the axial direction of the heat transfer tube, and the heat transfer tube inserted through the hole in the tube plate is taken out from between the opposing tube plates. The replacement heat transfer tube integrated with the heat transfer tube is moved to the place where the heat transfer tube was originally located without aligning the hole of the tube plate and the end of the replacement heat transfer tube, and the replacement heat transfer tube. A heat tube can be attached to the tube sheet. Therefore, for example, since only the heat transfer tube in which the hole is broken can be easily replaced, it is possible to avoid replacing all the heat transfer tubes with the tube plate as in the prior art, thereby reducing the maintenance cost of the heat exchanger.

  The replacement heat transfer tube may be moved to a position where the tube plate is mounted while cutting the heat transfer tube exposed from between the opposing tube plates.

  The connection jig has connection portions that are smaller than the inner diameters of the heat transfer tubes and the replacement heat transfer tubes and have elasticity at both ends, and both the connection portions are the heat transfer tube end portions and the replacement heat transfer tubes. By supplying and pressurizing fluid to the inside of both the connection parts in a state of being inserted from the ends of the two connection parts, the both connection parts are expanded to connect the connection jig, the heat transfer tube, and the replacement heat transfer tube. May be.

  The surface of the connecting portion may have a predetermined coefficient of friction.

  The connecting jig includes a disk-shaped flange having a diameter larger than the inner diameter of the heat transfer tube and the replacement heat transfer tube, and protrusions protruding on both sides of the flange, The diameter may be smaller than the inner diameter of the heat transfer tube and the replacement heat transfer tube.

  The connecting jig is a rod-shaped member in which a screw is formed at one end and a reverse screw is formed at the other end, and a screw is formed at either end of the heat transfer tube or the replacement heat transfer tube. In addition, a reverse screw is formed at an end portion of the heat transfer tube or the replacement heat transfer tube in which the screw is not formed, a screw and a reverse screw of the connection jig, and a screw of the heat transfer tube and the replacement heat transfer tube In addition, the connecting jig, the heat transfer tube, and the replacement heat transfer tube may be connected by screwing a reverse screw.

  According to the present invention, by exchanging the heat transfer tubes of the multi-tube heat exchanger individually, it is possible to avoid replacing all the heat transfer tubes together with the tube plate, and to reduce maintenance costs.

It is a schematic longitudinal cross-sectional view which shows an example of the structure of the multitubular heat exchanger with which the exchange method of the heat exchanger tube concerning this Embodiment is applied. It is a longitudinal cross-sectional view which shows the outline of a structure of a connection jig. It is explanatory drawing which shows the state which connected the connection part of the connection jig, and the edge part of the heat exchanger tube. It is explanatory drawing which shows the state which connected the connection part of the connection jig, and the edge part of the heat exchanger tube. It is explanatory drawing which shows the state which made the heat exchanger tube for replacement approach between the tube sheets. It is explanatory drawing which shows the state which moved the heat exchanger tube for exchange to the position where the heat exchanger tube was originally. It is explanatory drawing which shows the outline of a structure of the connection jig concerning other embodiment. It is explanatory drawing which shows a state by connecting a heat exchanger tube and the heat exchanger tube for replacement | exchange by the connection jig concerning other embodiment. It is explanatory drawing which shows the outline of a structure of the connection jig concerning other embodiment. It is explanatory drawing which showed a mode that it pulled out, cut | disconnecting a heat exchanger tube.

  Hereinafter, in describing the heat transfer tube replacement method according to the present embodiment, first, the configuration of a multi-tube heat exchanger to which the heat transfer tube replacement method according to the present embodiment is applied will be described. FIG. 1 is a schematic longitudinal sectional view showing an example of the configuration of a multi-tube heat exchanger 1 to which the heat transfer tube replacement method according to the present embodiment is applied.

  The multi-tube heat exchanger 1 has a plurality of straight tubular heat transfer tubes 10, two tube plates 11, 12 provided opposite to each other, and a body 13. The tube plates 11 and 12 have a substantially disc shape, and the tube plates 11 and 12 are formed with a plurality of through holes penetrating in the thickness direction. Both end portions of each heat transfer tube 10 are provided through the through holes of the tube plates 11 and 12 and supported by the tube plates 11 and 12.

  The body 13 has, for example, a cylindrical shape. The tube plates 11 and 12 are accommodated in the body 13 together with the heat transfer tube 10. Flange portions 13 a and 13 a are provided at both ends of the body 13. Lids 20 and 21 are connected to the flange portions 13 a and 13 a, respectively, and the water chamber A is surrounded by the lid 21, the tube plate 12, and the body 13 in an area surrounded by the lid 20, the tube plate 11, and the body 13. Water chambers B are respectively formed in the regions.

  For example, a partition plate 22 is provided inside the water chamber A and between the lid 20 and the tube plate 11 along the direction in which the heat transfer tube 10 extends. The partition plate 22 partitions the water chamber A into an upper water chamber A1 and a lower water chamber A2. Further, an inlet nozzle 30 that communicates with the upper water chamber A1 and an outlet nozzle 31 that communicates with the lower water chamber A2 are provided at positions of the body 13 between the lid 20 and the tube plate 11, respectively. . For example, the fluid supplied from the inlet nozzle 30 flows into the water chamber B through the upper water chamber A1 and the heat transfer tube 10, and is discharged from the outlet nozzle 31 through the heat transfer tube 10 and the lower water chamber A2 from the water chamber B. Is done.

  Further, for example, at a position between the tube plate 11 and the tube plate 12 in the body 13, for example, a trunk side outlet nozzle 40 is located at an upper position near the water chamber A, and a trunk side inlet is located at a lower position near the water chamber B. A nozzle 41 is provided. For example, the fluid supplied from the trunk side inlet nozzle 41 is discharged from the trunk side outlet nozzle 40 while exchanging heat with the fluid flowing through the heat transfer pipe 10 inside the trunk 13.

  Next, an example in the case of applying the replacement method for the heat transfer tube 10 according to the present embodiment in the multi-tube heat exchanger 1 will be described.

  In carrying out the method for replacing the heat transfer tube 10 according to the present embodiment, for example, a connection jig 50 as shown in FIG. 2 is used. The connecting jig 50 will be described.

  The connection jig 50 includes, for example, a substantially cylindrical main body 51 and connection portions 52 and 53 provided at both ends of the main body 51. The connection parts 52 and 53 are formed of, for example, a hollow elastic member, and are connected to the main body part 51 in an airtight manner. A flow path 54 communicating with the inside of the connection part 52 and the connection part 53 is formed inside the main body part 51. For example, a fluid supply pipe 55 for supplying a fluid such as compressed air is communicated with the flow path 54. The fluid supply pipe 55 is connected by supplying compressed air from a compressed air supply source (not shown). Compressed air can be supplied to the inside of the part 52 and the connection part 53. The length L of the fluid supply pipe 55 is configured to be smaller than the inner radius of the heat transfer pipe 10, for example. A plug 56 is provided at the tip of the fluid supply pipe 55, and a state in which compressed air is sealed inside the connection parts 52 and 53 can be maintained. 2 shows an example in which the flow path 54 and the fluid supply pipe 55 are provided separately for the connection part 52 and the connection part 53, the flow path 54 and the fluid supply pipe 55 are connected to the connection part 52, 53 may be provided in common.

  The connection part 52 and the connection part 53 are configured to have a diameter that is larger than the inner diameter of the heat transfer tube 10 when compressed air having a predetermined pressure is supplied to the inside. Therefore, for example, by supplying the compressed air from the fluid supply pipe 55 in a state where the connection part 52 is inserted into the end part of the heat transfer tube 10, the connection part 52 can be brought into pressure contact with the inside of the heat transfer pipe 10.

  The surfaces of the connection part 52 and the connection part 53 are covered with a resistance member 60 having a predetermined friction coefficient, for example. The resistance member 60 has, for example, the same diameter as the inner diameter of the heat transfer tube 10. Therefore, for example, when a force for pulling the connection jig 50 out of the heat transfer tube 10 is applied to the connection jig 50 or the heat transfer pipe 10 in a state where the connection portion 52 is pressed against the inside of the heat transfer pipe 10, The jig 50 can be prevented from falling off the heat transfer tube 10. Note that the friction coefficient of the resistance member 60 is appropriately set so that the connection portions 52 and 53 are not dropped from the heat transfer tube 10 due to a force acting on the connection portions 52 and 53 when the heat transfer tube 10 described later is replaced. is there.

  In exchanging the heat transfer tube 10 using the connection jig 50 configured as described above, first, all the fluid to be heat exchanged is removed from the multi-tube heat exchanger 1 and then the next. In addition, the lid bodies 20 and 21 are removed from the multitubular heat exchanger 1. Next, for example, the connection portion 52 is inserted into the end portion on the tube plate 11 side in the heat transfer tube 10 to be replaced. Next, after pressurizing the inside of the connection portion 52, the fluid supply pipe 55 is plugged 56 so that the connection portion 52 is pressed against the inside of the heat transfer tube 10 as shown in FIG. 3. Thereby, the heat exchanger tube 10 and the connection part 52 are connected.

  Next, as shown in FIG. 4, the connection portion 53 is inserted into an arbitrary end portion of a new heat transfer tube for replacement (hereinafter referred to as “exchange heat transfer tube”) 70, and the inside of the connection portion 53 is pressurized. The connection part 53 and the heat exchanger tube 70 for replacement | exchange are connected by this. Thereby, the heat exchanger tube 10 and the exchange heat exchanger tube 70 can be made into the integral straight tube.

  Next, the heat transfer tube 10 to which the replacement heat transfer tube 70 is connected via the connection jig 50 is pulled, for example, from the tube plate 12 side. Thereby, as shown in FIG. 5, the replacement heat transfer tube 70 is caused to enter between the tube plates 11 and 12 using the heat transfer tube 10 as a guide. Then, by completely pulling out the heat transfer tube 10 from between the tube plates 11, 12, the replacement heat transfer tube 70 connected to the heat transfer tube 10 via the connection jig 50, for example, as shown in FIG. The heat pipe 10 is moved to the initial position, that is, to the position where the replacement heat transfer pipe 70 is attached to the tube plates 11 and 12. At this time, the replacement heat transfer tube 70 and the heat transfer tube 10 are connected in an integral straight line via the connection jig 50, so that when the replacement heat transfer tube 70 is inserted through the through hole of the tube plate 12, There is no need to align the end of the exchange heat transfer tube 70 and the through hole of the tube plate 12.

  When the heat transfer tube 10 is completely replaced with the replacement heat transfer tube 70, the plug 56 of the connection jig 50 is then removed, and the connection jig 50 is removed from the heat transfer tube 10 and the replacement heat transfer tube 70. Thereafter, both ends of the replacement heat transfer tube 70 replaced with the heat transfer tube 10 are expanded, and the replacement heat transfer tube 70 is fixed to the tube plates 11 and 12 to complete the mounting. Then, the lid bodies 20 and 21 are connected to the flange 13a, and a series of heat transfer tube 10 replacement operations are completed.

  According to the above embodiment, since the heat transfer tube 10 and the replacement heat transfer tube 70 are connected via the connection jig 50, the heat transfer tube 10 and the replacement heat transfer tube 70 can be formed into an integral straight tube. Then, by pulling out the connected heat transfer tube 10 and inserting the replacement heat transfer tube 70 between the tube plates 11 and 12 using the heat transfer tube 10 as a guide, the end of the replacement heat transfer tube 70 and the tube plate 12 are inserted. The replacement heat transfer tube 70 can be inserted into the through hole of the tube plate 12 without aligning with the through hole. Therefore, the replacement heat transfer tube 70 can be easily moved to the position where the heat transfer tube 10 was originally located. Therefore, for example, since only the heat transfer tube 10 in which the hole has been broken can be easily replaced, it is not necessary to replace the healthy heat transfer tube 10 in which no hole has been broken, as in the conventional case, and as a result, The maintenance cost of the multi-tube heat exchanger 1 can be reduced.

  Conventionally, every time the heat transfer tube 10 is broken, the broken heat transfer tube 10 is closed with a stopper, so that the capacity of the multi-tube heat exchanger 1 is reduced each time. However, according to the above embodiment, since the heat transfer tube 10 can be replaced whenever a hole breaks in the heat transfer tube 10, for example, the heat exchange capacity of the multi-tube heat exchanger 1 can always be kept at the highest level. it can.

  In the above embodiment, the replacement heat transfer tube 70 is moved by pulling out the heat transfer tube 10 out of the heat transfer tube 10 and the replacement heat transfer tube 70 integrated by the connecting jig 50. For example, the replacement heat transfer tube The replacement heat transfer tube 70 may be moved to a position where the replacement heat transfer tube 70 is attached to the tube plates 11 and 12 by pushing the 70 from the tube plate 11 toward the tube plate 12. How the force is applied to the integrated heat transfer tube 10 and the replacement heat transfer tube 70 is appropriately determined according to the working environment around the multi-tube heat exchanger 1, and this embodiment It is not limited to the contents of.

  For example, when the heat transfer tube 10 is replaced by pushing in the replacement heat transfer tube 70, the inner diameter of the heat transfer tube 10 and the replacement heat transfer tube 70 as shown in FIG. You may use the connection jig 81 provided with the collar part 80 with a diameter larger than the outer diameter of the heat exchanger tube 10 and the heat exchanger tube 70 for replacement | exchange. The flange 80 is formed, for example, in a substantially disc shape, and protrusions 82 that project in a direction perpendicular to the flange 80 are provided on both sides of the flange 80. The protrusion 82 is formed in a cylindrical shape having a diameter larger than the inner diameters of the heat transfer tube 10 and the replacement heat transfer tube 70 so that the protrusion 82 can be inserted into the end portions of the heat transfer tube 10 and the replacement heat transfer tube 70, for example.

  When the connection jig 81 is used, for example, as shown in FIG. 8, the replacement heat transfer tube 70 is oriented in the direction of the heat transfer tube 10 in a state in which the protrusions 82 are inserted into the end portions of the heat transfer tube 10 and the replacement heat transfer tube 70. The replacement heat transfer tube 70 can be replaced with a heat transfer tube.

  For example, if it can be peeled later, for example, an adhesive is applied to the protrusion 82 of the connection jig 81, and the connection jig 81, the heat transfer tube 10 and the replacement heat transfer tube 70 are connected by the adhesive. For example, the heat transfer tube 10 may be pulled out from the tube plates 11 and 12. Alternatively, if the replacement heat transfer tube 70 has an extra length, in other words, if it is formed longer than the distance between the tube plates 11, 12, it is connected to the connection jig 81 by an adhesive. The part may be cut after the replacement heat transfer tube 70 is mounted on the tube plates 11 and 12.

  Further, instead of the connecting jigs 50 and 81, a screw 91 is attached to one end of a rod-shaped member 90 having the same diameter as that of the exchange heat transfer tube 70 and the heat transfer tube 10 as shown in FIG. Alternatively, a connection jig 93 having a reverse screw 92 formed at the end thereof may be used. For the connection between the connection jig 93 and the heat transfer tube 10 and the replacement heat transfer tube 70, for example, a screw is formed at one end of the heat transfer tube 10 and the replacement heat transfer tube 70, and a reverse screw is formed at the other end. To do. Then, the heat transfer tube 10 and the replacement heat transfer tube are formed by the connection jig 93 by forming the screw 91 and the reverse screw 92 of the connection jig 93 into the screw and the reverse screw formed in the heat transfer tube 10 and the replacement heat transfer tube 70. 70 can be integrated. The connection jig 93 can handle both the case where the heat transfer tube 10 is pulled out and the case where the replacement heat transfer tube 70 is pushed. Further, since the screw 91 and the reverse screw 92 are formed, even if a force in the twisting direction acts on the heat transfer tube 10, the replacement heat transfer tube 70 and the connection jig 93, the heat transfer tube 10 and the replacement tube are exchanged from the connection jig 93. It is possible to suppress the heat transfer tube 70 from falling off.

  When the heat transfer tube 70 for replacement is moved to the position where the heat transfer tube 10 was originally located, for example, as shown in FIG. 10, it was exposed from between the tube plates 11, 12, that is, exposed outside the tube plate 12. The replacement heat transfer tube 70 may be moved while the heat transfer tube 10 is appropriately cut. Even when the work space on the lid 21 side of the multi-tube heat exchanger 1 is limited and it is difficult to pull out the heat transfer tube 10, the heat transfer tube 10 exposed to the outside of the tube plate 12 is cut off. The work space on the tube sheet 12 side can be minimized. Even in such a case, since the replacement heat transfer tube 70 and the heat transfer tube 10 are connected via the connection jig, the heat transfer tube still remains even if the end of the heat transfer tube 10 on the side opposite to the connection jig is cut. Reference numeral 10 functions as a guide for the exchange heat transfer tube 70.

  The present invention is useful when exchanging the heat transfer tubes of a multitubular heat exchanger.

DESCRIPTION OF SYMBOLS 1 Multi-tube heat exchanger 10 Heat transfer tube 11, 12 Tube plate 13 Body 13a Flange part 20, 21 Cover body 22 Partition plate 30 Entrance nozzle 31 Outlet nozzle 40 Body side outlet nozzle 41 Body side inlet nozzle 50 Connection Jig 51 Body portion 52, 53 Connection portion 54 Flow path 55 Fluid supply pipe 56 Plug 60 Resistance member 70 Replacement heat transfer tube 80 Hook portion 81 Connection jig 82 Projection portion 90 Rod-shaped member 91 Screw 92 Reverse screw A1 Upper water chamber A2 Lower water chamber

Claims (6)

A multi-tubular heat having a tube plate provided in opposition, a plurality of straight tubular heat transfer tubes inserted through holes formed in the tube plate, and a body housing the tube plate and the heat transfer tubes In the exchanger, a method of replacing the heat transfer tube,
A replacement heat transfer tube is connected to one end of the heat transfer tube inserted through the hole in the tube plate via a connection jig,
The replacement heat transfer tube with the heat transfer tube as a guide by applying a force of either pushing or pulling along the axial direction of the heat transfer tube to at least one of the heat transfer tube or the replacement heat transfer tube The heat transfer tube replacement method is characterized in that the heat transfer tube is moved to a position where it is attached to the tube plate. 2. The heat transfer tube according to claim 1, wherein the heat transfer tube exposed from between the opposing tube plates is moved to a position where the replacement heat transfer tube is attached to the tube plate. 3. method of exchange. The connecting jig has a connecting portion having a diameter smaller than the inner diameter of the heat transfer tube and the replacement heat transfer tube and having elasticity at both ends,
By supplying and pressurizing fluid inside the two connection portions in a state where the both connection portions are inserted from the end portions of the heat transfer tube ends and the end portions of the replacement heat transfer tubes, the both connection portions are expanded and the 3. The heat transfer tube replacement method according to claim 1, wherein the connection jig is connected to the heat transfer tube and the replacement heat transfer tube. 4. The heat transfer tube replacement method according to claim 3, wherein a surface of the connecting portion has a predetermined coefficient of friction. The connection jig includes a disk-shaped flange having a diameter larger than the inner diameter of the heat transfer tube and the replacement heat transfer tube, and protrusions protruding on both sides of the flange.
The method for replacing a heat transfer tube according to claim 1, wherein the protrusion has a diameter smaller than an inner diameter of the heat transfer tube and the replacement heat transfer tube. The connecting jig is a rod-shaped member in which a screw is formed at one end and a reverse screw is formed at the other end.
A screw is formed at either end of the heat transfer tube or the replacement heat transfer tube, and a reverse screw is formed at the end of the heat transfer tube or the replacement heat transfer tube where the screw is not formed,
The connection jig, the heat transfer tube, and the replacement heat transfer tube are connected by screwing the screw and reverse screw of the connection jig, and the screw and reverse screw of the heat transfer tube and the replacement heat transfer tube, respectively. The heat transfer tube replacement method according to claim 1, wherein the heat transfer tube is replaced with a heat transfer tube.

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