JP2017166792A - Method of repairing exhaust heat recovery boiler - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of repairing an exhaust heat recovery boiler capable of simplifying a repairing work of a heat exchange panel.SOLUTION: In a method of repairing an exhaust heat recovery boiler in which heat exchange panels P configured by connecting a plurality of heat transfer pipes 3 between an upper pipe header and a lower pipe header, are arranged in parallel in an exhaust gas flowing direction of a gas turbine, replacement panel parts PZ manufactured with a form including a replacement lower pipe header 2Z corresponding to the lower pipe header of the heat exchange panel P and an exhaust heat transfer pipe part 3Z corresponding to a replacement object part at a lower side of the plurality of heat transfer pipe 3, are prepared in advance. The plurality of heat transfer pipes 3 of the heat exchange panels P are cut in a state of separating the replacement object parts, then upper end portions of the replacement heat transfer pipe parts 3Z of the replacement panel parts PZ are welded to lower end portions of upper pipe parts 3U from which the replacement object part are separated, of the heat transfer pipes 3, and the replacement panel parts PZ are mounted on the heat exchange panels P.SELECTED DRAWING: Figure 9

Description

  The present invention provides a heat exchange panel in which a plurality of heat transfer tubes arranged in parallel in the axial direction of the upper header and the lower header arranged in parallel are connected between the upper header and the lower header. The present invention relates to a method for repairing an exhaust heat recovery boiler arranged in parallel in an exhaust gas flow direction of a gas turbine.

  A combined cycle power plant generates power by collecting exhaust heat of exhaust gas from a gas turbine in addition to power generation by a gas turbine, and generates steam by driving the steam turbine with the steam. In the combined cycle power plant, the boiler recovers exhaust heat of the exhaust gas from the gas turbine and generates steam.

As the exhaust heat recovery boiler, for example, as shown in FIG. 24, a low pressure evaporator U1, a low pressure superheater U2, a medium pressure economizer V1, an intermediate pressure evaporator V2, an intermediate pressure superheater V3, and a high pressure economizer W1. , The high-pressure evaporator W2, the high-pressure superheater W3, and the reheater T are provided with a plurality of types of heat exchangers, and the plurality of types of heat exchangers are configured using the heat exchange panel P. It will be.
In addition, GT in a figure is a gas turbine.

Corrosion may occur due to the flow of fluid in the heat exchange panel, and the heat exchange panel that is prone to corrosion constitutes a economizer or evaporator in which the fluid is water phase or gas-liquid two phase. It is a heat exchange panel.
Incidentally, the corrosion form is different from general corrosion due to oxidation, and characteristic corrosion occurs at the location where the flow path branches or the cross section of the flow path changes. This corrosion is called flow accelerated corrosion, and is a corrosion that occurs when certain conditions are met.

  In addition, when looking at the heat exchange panel, the lower part is more susceptible to flow accelerated corrosion than the upper part, and heat transfer tubes etc. are thinned by corrosion, so the wall thickness becomes the required minimum thickness. Need to be repaired.

  As such a repair method, there is a method of cutting and removing a lower portion of the heat transfer tube where corrosion has occurred, and then connecting a healthy heat transfer tube portion to the cut portion of the heat transfer tube by welding (for example, , See Patent Document 1).

  Incidentally, in Patent Document 1, when corrosion occurs in the heat transfer tube of the heat exchange panel on the inner side of the heat exchange panel unit in which a plurality of heat exchange panels are closely arranged, the heat transfer tube in which corrosion has occurred, Among a plurality of heat transfer tubes located on both sides of the heat transfer tube on which corrosion has occurred and a plurality of heat transfer tubes on the heat exchange panel in front of the heat transfer tube on which corrosion has occurred, Only the heat transfer tube located on the front side of the heat transfer tube located on the side of the heat transfer tube is cut and removed, and then, among the cut heat transfer tubes, the heat transfer tube adjacent to the uncut heat transfer tube is cut. It is described that a stopper plug is attached to the end, and then a healthy heat transfer tube portion is connected to a cut portion of the heat transfer tube not attached with the stopper plug.

  In addition, it is described that the reason why the healthy heat transfer tube portion is not connected to all the cut heat transfer tubes is that the cost increases when the healthy heat transfer tube portion is connected to all the heat transfer tubes.

Japanese Patent No. 4912430

  Since the flow state of fluid (water and steam) in the plurality of heat transfer tubes of the heat exchange panel is substantially the same, the flow of corrosion to the lower part of one of the plurality of heat transfer tubes of the heat exchange panel When corrosion occurs, it can be considered that the lower portions of other heat transfer tubes are also corroded.

  Therefore, when flow accelerated corrosion occurs in the lower part of one of the plurality of heat transfer tubes of the heat exchange panel, the lower part of the other heat transfer tube of the heat exchange panel is used as the part to be replaced. It can be considered that it is desirable to replace the part with a healthy heat transfer tube.

When replacing the heat exchange panel heat transfer tube with a healthy heat transfer tube part, for example, it is conceivable to replace the lower part (replacement target part) of all the heat transfer tubes with a sound heat transfer tube part. As in the prior art, it is conceivable to cut and remove the lower portion of the heat transfer tube, and then connect a healthy heat transfer tube portion to the cut portion of the heat transfer tube by welding.
However, for all of the plurality of (for example, 80) heat transfer tubes of the heat exchange panel, the lower part of the heat transfer tube (replacement target portion) is cut and removed, and then the cut portion of the heat transfer tube is healthy. The work of connecting the heat transfer tube portions by welding has a disadvantage that it takes a lot of work.

By the way, generally, the lower end of the heat transfer tube is welded to the peripheral portion of the connection hole in the lower header and the surface portion of the heat transfer tube in a state of being inserted into the connection hole formed in the lower header. It will be connected to the lower header.
And flow acceleration corrosion tends to occur in the lower end side part connected to the lower header of a heat exchanger tube.

  Therefore, in order to replace the lower part (replacement target part) of the heat transfer tube with a healthy heat transfer tube part, the portion corresponding to the upper end of the lower part (replacement target part) of the heat transfer tube is cut and the lower end part is lower. While separating from the header, remove the lower part of the heat transfer tube (the part to be replaced), then butt weld the upper end of the healthy heat transfer tube to the lower end of the cut heat transfer tube, and The lower end portion of the heat transfer tube portion is inserted and welded into the lower header.

  However, the work of separating the lower end portion of the lower portion of the heat transfer tube (the replacement target portion) from the lower header and the operation of inserting and welding the lower end portion of the healthy heat transfer tube portion to the lower header are troublesome and cumbersome. Due to the work, there is an inconvenience that the work of replacing the lower part of the heat transfer tube (the part to be replaced) with a healthy heat transfer tube part, that is, the troublesome work of repairing the heat exchange panel is troublesome. is there.

  Incidentally, for example, when a heat exchanger such as a high pressure economizer or a low pressure economizer is configured in a form in which a plurality of heat exchange panels are closely arranged along the exhaust gas flow direction of the gas turbine, If flow accelerated corrosion occurs in the heat transfer tubes of one of the heat exchange panels that make up the exchanger, the flow accelerated corrosion also proceeds in the heat transfer tubes of the other heat exchange panels. Can be considered.

  Therefore, when configuring a heat exchanger in a form in which a plurality of heat exchange panels are closely arranged along the exhaust gas flow direction of the gas turbine, one of the plurality of heat exchange panels constituting the heat exchanger. When accelerated corrosion occurs in the heat transfer tubes of one heat exchange panel, it is necessary to replace the lower part of the heat transfer tubes of all the heat exchange panels with a healthy heat transfer tube part as a replacement target part. For each of the plurality of heat exchange panels, it is necessary to perform troublesome and complicated repair work.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide a method for repairing an exhaust heat recovery boiler capable of facilitating repair work of a heat exchange panel.

A method for repairing an exhaust heat recovery boiler according to the present invention includes a plurality of heat transfer tubes arranged in parallel along a tube axial direction of an upper header and a lower header arranged in parallel with the upper header and the lower header. The heat exchange panel connected in between is a method for repairing a waste heat recovery boiler arranged in parallel in the exhaust gas flow direction of the gas turbine, and its characteristic configuration is:
A replacement panel portion manufactured in a form including a replacement lower header corresponding to the lower header of the heat exchange panel and a replacement heat transfer tube portion corresponding to a replacement target portion below the plurality of heat transfer tubes. Prepare in advance,
Cutting the plurality of heat transfer tubes of the heat exchange panel into a state in which the replacement target portion is cut off, and separating the lower header of the heat exchange panel and the replacement target portion of the heat transfer tube;
Thereafter, the upper end portion of the replacement heat transfer tube portion of the replacement panel portion is welded to the lower end portion of the upper tube portion from which the replacement target portion of the heat transfer tube is cut, and the replacement panel portion is heated. It is mounted on a replacement panel.

  That is, a replacement panel portion manufactured in advance in a form including a replacement lower header corresponding to the lower header of the heat exchange panel and a replacement heat transfer tube portion corresponding to a replacement target portion below the plurality of heat transfer tubes. Prepare.

  By the way, in order to manufacture the replacement panel part, the lower end of the replacement heat transfer tube part is inserted and welded to the replacement lower header, but the replacement panel part is manufactured widely in the factory, etc. Since it can be performed using a positioning jig or the like in the space, the work of inserting and welding the lower end portion of the replacement heat transfer tube portion to the replacement lower header can be easily performed.

And when flow accelerated corrosion occurs in the lower part of the heat transfer tube and repairs the heat exchange panel, first, the plurality of heat transfer tubes of the heat exchange panel are replaced with the part to be exchanged on the lower side of the heat transfer tube. It cut | disconnects in the state to isolate | separate, and isolate | separates the exchange object part of the lower header of a heat exchange panel and a heat exchanger tube.
Thereafter, the upper end of the replacement heat transfer tube portion of the replacement panel portion is welded to the lower end of the upper tube portion from which the replacement target portion of the heat transfer tube is cut off, and the replacement panel portion is attached to the heat exchange panel. become.

  Therefore, when repairing the heat exchange panel, the lower end of the lower part of the heat transfer tube (the part to be replaced) is separated from the lower header, and the lower end of the replacement heat transfer tube is inserted into the lower header and welded. Therefore, the heat exchanging panel can be repaired easily.

  In short, according to the method for repairing an exhaust heat recovery boiler of the present invention, the repair work of the heat exchange panel can be facilitated.

Further, according to a further characteristic configuration of the method for repairing the exhaust heat recovery boiler of the present invention, a plurality of the heat exchange panels are juxtaposed in a close state along the exhaust gas flow direction,
Among the plurality of heat exchange panels arranged in close proximity, a plurality of heat exchange panels heading from one end side to the other end side in the arrangement direction are used as heat exchange panels to be exchanged, and one end of the heat exchange panels to be exchanged A plurality of the heat transfer tubes are sequentially cut from the heat exchange panel on the side toward the heat exchange panel on the other end side so as to cut off the replacement target portion, and the lower header and the heat transfer of the heat exchange panel are cut off. Separating the replacement part of the heat pipe,
Thereafter, from the heat exchange panel on the other end side of the plurality of heat exchange panels to be exchanged toward the heat exchange panel on the one end side, the upper end portion of the heat transfer tube portion for replacement of the replacement panel portion is sequentially The replacement panel portion is attached to the heat exchange panel by welding to the lower end portion of the upper tube portion from which the replacement target portion of the heat transfer tube is cut off.

  That is, in a form in which a plurality of heat exchange panels are arranged in close contact along the exhaust gas flow direction, among the plurality of heat exchange panels arranged in close contact, a plurality from one end side to the other end side in the arrangement direction When the heat exchange panel is used as a heat exchange panel to be exchanged, first, among the heat exchange panels to be exchanged, a plurality of heat exchange panels are sequentially arranged from one end side heat exchange panel to the other end side heat exchange panel. The heat transfer tube is cut into a state in which the replacement target portion is separated, and the lower header of the heat exchange panel and the replacement target portion of the heat transfer tube are separated.

  In other words, the heat exchange tube of the heat exchange panel is cut into a state in which the exchange target part is cut off, and the lower header of the heat exchange panel and the exchange target part of the heat transfer pipe are separated. It carries out sequentially toward the heat exchange panel of the other end side from the heat exchange panel of the other end side.

  Then, the upper end portion of the replacement heat transfer tube portion of the replacement panel portion is sequentially placed in the heat transfer tube from the heat exchange panel on the other end side of the plurality of heat exchange panels to be replaced toward the heat exchange panel on the one end side. It welds to the lower end part of the upper side pipe part from which the exchange object part was cut off, and attaches the panel part for exchange to a heat exchange panel.

  That is, welding the upper end portion of the replacement heat transfer tube portion of the replacement panel portion to the lower end portion of the upper tube portion from which the replacement target portion of the heat transfer tube is cut off, and mounting the replacement panel portion on the heat exchange panel Are sequentially performed from the heat exchange panel on the other end side of the plurality of heat exchange panels to be exchanged toward the heat exchange panel on the one end side.

  Therefore, in a form in which a plurality of heat exchange panels are arranged in close contact along the exhaust gas flow direction, among the plurality of heat exchange panels arranged in close contact, a plurality of heads from one end to the other end in the alignment direction Even when the heat exchange panel is used as the heat exchange panel to be exchanged, the lower end of the lower part of the heat transfer tube (the part to be exchanged) is separated from the lower header, or the lower end of the exchange heat transfer tube part is Since the work of inserting and welding to the lower header becomes unnecessary, the work of repairing a plurality of heat exchange panels to be replaced can be easily performed.

  In short, according to the further characteristic configuration of the method for repairing an exhaust heat recovery boiler of the present invention, it is possible to facilitate the repair work of a plurality of heat exchange panels arranged in close contact.

  Moreover, the further characteristic structure of the repair method of the exhaust heat recovery boiler of the present invention is characterized in that the lengths of the exchange target portions of the heat transfer tubes in the plurality of exchange target heat exchange panels are the same. It is in.

  That is, in a form in which a plurality of heat exchange panels are arranged in close contact along the exhaust gas flow direction, among the plurality of heat exchange panels arranged in close contact, a plurality from one end side to the other end side in the arrangement direction In the case where the heat exchange panels are the heat exchange panels to be exchanged, the lengths of the exchange target portions of the heat transfer tubes in the plurality of heat exchange panels to be exchanged are the same, so that each of the plurality of heat exchange panels to be exchanged The length of the replacement heat transfer tube in the replacement panel portion to be attached to is the same.

  Therefore, since the replacement panel part can be shared for a plurality of heat exchange panels to be replaced, it is only necessary to produce a replacement panel part of one specification for a plurality of heat exchange panels to be replaced. The panel part can be easily manufactured.

  In short, according to the further characteristic configuration of the method for repairing an exhaust heat recovery boiler of the present invention, it is possible to facilitate the manufacture of the replacement panel portion.

Further, a further characteristic configuration of the method for repairing an exhaust heat recovery boiler of the present invention is that the plurality of heat transfer tubes arranged along the axial direction of the tube are displaced to the upper side in the exhaust gas flow direction. In the form of being alternately installed along the tube axis direction, the state and the lower side displacement state that is displaced to the lower side of the exhaust gas flow direction,
Of the heat transfer tubes in the upper side deviation state and the heat transfer tubes in the lower side deviation state in the heat exchange panel to be exchanged, one end side in the arrangement direction of the plurality of heat exchange panels to be exchanged. The length of the exchange target part of the heat transfer tube is longer than the length of the exchange target part of the heat transfer tube that is the other end side in the arrangement direction of the plurality of heat exchange panels to be exchanged, and a plurality of the exchanges The length of the exchange target part of the heat transfer tube in the upper side deviation state in the target heat exchange panel is the same, and the replacement target of the heat transfer tube in the lower side deviation state in the plurality of heat exchange panels to be exchanged The length of the parts is the same.

  That is, a plurality of heat transfer tubes arranged in parallel along the tube axial direction of the upper header and the lower header are parallel to the upper side displacement state where the exhaust gas flow direction is shifted to the upper side and the exhaust gas flow direction. Since it is provided in the form of being alternately installed along the tube axis direction in the lower side displacement state that is shifted to the lower side, the heat transfer tubes adjacent in the tube axis direction are arranged in the tube axis direction. While arranging them close to each other, the exhaust gas of the gas turbine can be appropriately flowed to each of the plurality of heat transfer tubes to improve the exhaust heat recovery efficiency.

  And in the form where a plurality of heat exchange panels are arranged in close contact along the exhaust gas flow direction, among the plurality of heat exchange panels arranged in close contact, a plurality from one end side to the other end side in the alignment direction When the heat exchange panel is a heat exchange panel to be exchanged, a plurality of exchange targets of the heat transfer tubes in the upper side deviation state and the heat transfer tubes in the lower side deviation state in the heat exchange panel to be exchanged The length of the exchange target part of the heat transfer tube that is one end side in the arrangement direction of the heat exchange panels is larger than the length of the exchange target part of the heat transfer tube that is the other end side in the arrangement direction of the plurality of exchange target heat exchange panels. When welding the upper end of the replacement heat transfer tube portion of the replacement panel portion to the lower end portion of the upper tube portion from which the replacement target portion of the heat transfer tube is cut off, the workability of the welding operation is increased. Can improve .

  That is, when the upper end portion of the replacement heat transfer tube portion of the replacement panel portion is welded to the lower end portion of the upper tube portion from which the replacement target portion of the heat transfer tube is cut, the upper portion of the heat transfer tube where the replacement target portion is cut off. Since the height of the lower end portion of the side tube portion is different between the adjacent ones in the tube axis direction, the replacement panel with respect to the lower end portion of the upper side portion of the heat transfer tubes adjacent in the tube axis direction It is possible to improve the workability of the welding work, for example, it is possible to simultaneously weld the replacement heat transfer tube portion by another worker.

  Further, the lengths of the replacement target portions of the heat transfer tubes in the upper side deviation state in the plurality of heat exchange panels to be exchanged are the same, and the heat exchange tubes in the lower side deviation state in the heat exchange panels to be exchanged are the same. Since the lengths of the parts are the same, the replacement panel part to be mounted on each of the plurality of heat exchange panels to be replaced can be shared by the plurality of heat exchange panels to be replaced. As for the replacement panel, it is only necessary to manufacture a replacement panel portion having one specification, so that the replacement panel portion can be easily manufactured.

  In short, according to the further characteristic configuration of the method for repairing the exhaust heat recovery boiler of the present invention, it is possible to improve the workability of the welding work while improving the exhaust heat recovery efficiency, and to manufacture the replacement panel portion. Simplification can be achieved.

Further, a further characteristic configuration of the method for repairing an exhaust heat recovery boiler of the present invention is that the plurality of heat transfer tubes arranged along the axial direction of the tube are displaced to the upper side in the exhaust gas flow direction. In the form of being alternately installed along the tube axis direction, the state and the lower side displacement state that is displaced to the lower side of the exhaust gas flow direction,
The length of the exchange target part of the heat transfer tube in the upper side deviation state and the heat transfer tube in the lower side deviation state in the heat exchange panel to be exchanged is the same, and a plurality of heats of the exchange target The length of the exchange target portion of the heat transfer tube is sequentially shortened from the heat exchange panel on one end side in the arrangement direction of the exchange panels toward the heat exchange panel on the other end side.

  That is, a plurality of heat transfer tubes arranged in parallel along the tube axial direction of the upper header and the lower header are parallel to the upper side displacement state where the exhaust gas flow direction is shifted to the upper side and the exhaust gas flow direction. Since it is provided in the form of being alternately installed along the tube axis direction in the lower side displacement state that is shifted to the lower side, the heat transfer tubes adjacent in the tube axis direction are arranged in the tube axis direction. While arranging them close to each other, the exhaust gas of the gas turbine can be appropriately flowed to each of the plurality of heat transfer tubes to improve the exhaust heat recovery efficiency.

  And in the form where a plurality of heat exchange panels are arranged in close contact along the exhaust gas flow direction, among the plurality of heat exchange panels arranged in close contact, a plurality from one end side to the other end side in the alignment direction When the heat exchange panel is the heat exchange panel to be exchanged, the length of the heat exchange tube in the upper side deviation state of the heat exchange panel to be exchanged and the part to be exchanged of the heat exchange tube in the lower side deviation state The length of the heat exchange tube replacement target portion in order from the heat exchange panel on one end side to the heat exchange panel on the other end side in the arrangement direction of the heat exchange panels to be replaced is the same. Therefore, it is possible to easily cut the plurality of heat transfer tubes of the heat exchange panel into a state in which the portion to be replaced on the lower side of the heat transfer tube is cut off, so that the heat transfer tube can be cut well. be able to.

  That is, since the length of the exchange target portion of the heat transfer tube in the upper side deviation state in the heat exchange panel to be exchanged is the same as the length of the exchange target portion of the heat transfer tube in the lower side deviation state, one heat exchange panel Since it is only necessary to cut the plurality of heat transfer tubes at the same height, the work of cutting the heat transfer tubes of the heat exchange panel to be replaced becomes easy.

  In addition, the length of the heat exchange tube replacement target portion is shortened sequentially from the heat exchange panel on the one end side in the direction of arrangement of the heat exchange panels to be replaced to the heat exchange panel on the other end side. After cutting the heat transfer tube of the heat exchange panel, when cutting the heat transfer tube of the heat exchange panel located on the inner side (the other end side) of the heat exchange panel, the cutting position is the heat exchange panel on the one end side Therefore, when the heat transfer tube of the heat exchange panel located on the inner side (the other end side) of the heat exchange panel on one end side is cut, the heat transfer panel on the one end side is transferred. The heat tube can be prevented from interfering, and the work of cutting the heat transfer tube of the heat exchange panel located on the inner side (the other end side) of the heat exchange panel on the one end side can be performed satisfactorily.

  In short, according to the further characteristic configuration of the exhaust heat recovery boiler repair method of the present invention of the present invention, it is possible to improve the workability of the heat transfer tube cutting work while improving the exhaust heat recovery efficiency.

Further, a further characteristic configuration of the method for repairing an exhaust heat recovery boiler according to the present invention includes a part including a connection portion of a connecting pipe in the tube axis direction among the plurality of heat transfer tubes arranged in the tube axis direction. A plurality of heat transfer tubes in the range of, the replacement panel portion, the replacement heat transfer tube portion corresponding to the replacement target portion in the replacement target heat transfer tube, and the lower header The replacement target heat transfer tube is created in a form including a replacement lower header portion corresponding to the replacement target lower header portion to which the replacement target heat transfer tube is connected,
When separating the exchange target portion in the exchange target heat transfer tube of the heat transfer tubes, cutting the replacement target lower header portion from the lower header and separating,
When the replacement panel portion is attached to the heat exchange panel, the upper end portion of the replacement heat transfer tube portion is welded to the lower end portion of the upper tube portion from which the replacement target portion of the replacement target heat transfer tube is separated. In addition, the end of the replacement lower header portion is welded to the end portion of the remaining lower header portion where the replacement target lower header portion in the lower header is cut off and remains. There is in point to do.

  That is, a connecting pipe for supplying fluid (water or steam) to the lower header or discharging from the lower header is connected to the lower header, and in the vicinity of the place where the connecting pipe is connected. Since the flow state of fluid (water or steam) changes, it can be considered that corrosion such as flow accelerated corrosion is likely to occur in the heat transfer tube near the place where the connecting tube is connected.

Therefore, among a plurality of heat transfer tubes arranged in the tube axis direction of the lower header, a plurality of heat transfer tubes in a partial range including the connection portion of the connecting tube in the tube axis direction are used as replacement heat transfer tubes. Replacement lower heat transfer tube portion corresponding to the replacement target heat transfer tube portion of the replacement target heat transfer tube and lower replacement header portion to which the replacement target heat transfer tube is connected, of the lower header. It is created in a form having a header portion.
That is, for replacement manufactured in a form including a replacement lower header portion corresponding to the replacement target lower header portion and a replacement heat transfer tube portion corresponding to the replacement target portion below the plurality of replacement target heat transfer tubes. Prepare the panel part.

  And when flow accelerated corrosion occurs in the lower part of the plurality of heat exchanger tubes among the plurality of heat exchanger tubes and repairs the heat exchange panel, first, the plurality of heat exchanger tubes to be replaced are In addition to cutting the replacement target portion on the lower side of the heat transfer tube, the replacement lower header portion of the heat exchange panel and the replacement target heat transfer tube replacement target Separate parts.

  Thereafter, in addition to welding the upper end portion of the replacement heat transfer tube portion of the replacement panel portion to the lower end portion of the upper tube portion from which the replacement target portion of the replacement target heat transfer tube is cut, the replacement lower header portion The end portion is welded to the end portion of the remaining lower header portion that remains after the replacement lower header portion in the lower header is cut off, and the replacement panel portion is attached to the heat exchange panel.

Therefore, when repairing the heat exchange panel, work to separate the lower part of the lower part of the heat transfer tube to be exchanged (the part to be exchanged) from the lower header, or the lower end of the replacement heat transfer tube to the lower header Since the work of inserting and welding is not required, the heat exchange panel can be repaired easily.
Moreover, since a plurality of heat transfer tubes in a part of the plurality of heat transfer tubes are used as the heat transfer tubes to be replaced, the repair work can be simplified, and the replacement panel portion By reducing the cost, the cost required for repair can be reduced.

  In short, according to the method for repairing an exhaust heat recovery boiler of the present invention, the repair work of the heat exchange panel can be simplified and the cost required for the repair can be reduced.

Partial cutaway schematic perspective view of a waste heat recovery boiler Longitudinal side view of heat exchange panel Partially omitted side view showing the arrangement of heat exchange panel units IV-IV line sectional view in FIG. Schematic showing the lower part of the heat exchange panel unit Schematic which shows the process of isolate | separating the exchange object part of 1st Embodiment. Schematic which shows the process of isolate | separating the exchange object part of 1st Embodiment. Schematic which shows the process in which the panel part for replacement | exchange of 1st Embodiment is mounted | worn. Schematic which shows the state which mounted | wore the replacement panel part of 1st Embodiment. Schematic which shows the process of isolate | separating the exchange object part of 2nd Embodiment. Schematic which shows the process of isolate | separating the exchange object part of 2nd Embodiment. Schematic which shows the process in which the panel part for replacement | exchange of 2nd Embodiment is mounted | worn. Schematic which shows the state which mounted | wore the replacement panel part of 2nd Embodiment. Schematic which shows the process of isolate | separating the exchange object part of 3rd Embodiment. Schematic which shows the process of isolate | separating the exchange object part of 3rd Embodiment. Schematic which shows the process in which the panel part for replacement | exchange of 3rd Embodiment is mounted | worn. Schematic which shows the state which mounted | wore the replacement panel part of 3rd Embodiment. Schematic plan view showing the replacement target lowering portion of the fourth embodiment Schematic which shows the fluid flow form with respect to the lower header of 4th Embodiment The schematic plan view which shows the state after separation of the exchange object lower part of 4th Embodiment Schematic top view which shows the state before mounting | wearing of the exchange object lower part of 4th Embodiment The schematic side view which shows the state after isolation | separation of the exchange object lower part close part of 4th Embodiment The schematic side view which shows the mounting state of the exchange object lower part close part of 4th Embodiment Partially cutout schematic perspective view showing a conventional example of an exhaust heat recovery boiler

[First Embodiment]
DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, a first embodiment of the invention will be described with reference to the drawings.
(Overall configuration of exhaust heat recovery boiler)
As shown in FIG. 1, the exhaust heat recovery boiler is provided with a duct-like boiler casing K that forms a flue for flowing the exhaust gas of the gas turbine GT. Inside the boiler casing K, a plurality of heat exchange panels are provided. Units N are provided in a form aligned along the exhaust gas flow direction, and a low-pressure steam drum D1, an intermediate-pressure steam drum D2, and a high-pressure steam drum D3 are provided on the ceiling of the boiler casing K.

In the present embodiment, nine heat exchange panel units N are juxtaposed along the flow direction of the exhaust gas of the gas turbine GT.
As shown in FIGS. 3 and 4, each of the heat exchange panel units N is configured to arrange a plurality of heat exchange panels P (see FIG. 2) in close contact along the exhaust gas flow direction of the gas turbine. .

  Between the second heat exchange panel unit N2 located second in the flow direction of the exhaust gas and the third heat exchange panel unit N3 located third, there is a denitration device M for reducing nitrogen oxides in the exhaust gas. Is provided.

Incidentally, as shown in FIG. 3, a plurality of heat exchange panel units N are juxtaposed at intervals along the exhaust gas flow direction, and an operator places a boiler casing between adjacent heat exchange panel units N. A working space S that is entered for inspection and repair is formed in a state where the floor portion Kt of K is used as a walking passage.
A manhole F is formed on the side wall of the boiler casing K so as to correspond to the work space S, and the operator can enter and leave the work space S through the manhole F.

  Of the plurality of heat exchange panel units N, the first heat exchange panel unit N1 located first in the flow direction of the exhaust gas is configured to form a superheater or a reheater for high-pressure steam, The second heat exchange panel unit N2 located second in the flow direction is configured to form a high-pressure evaporator.

As shown in FIG. 3, the third heat exchange panel unit N3 located third in the exhaust gas flow direction is configured to form a high-pressure evaporator and a superheater.
The fourth heat exchange panel unit N4 located fourth in the exhaust gas flow direction is configured to form a high-pressure economizer and a superheater.
The fifth heat exchange panel unit N5 located fifth in the exhaust gas flow direction is configured to form an evaporator.

The sixth heat exchange panel unit N6 located sixth in the exhaust gas flow direction is configured to form a high pressure economizer, an intermediate pressure economizer, and a high pressure economizer (see FIG. 5).
The seventh heat exchange panel unit N7 located seventh in the exhaust gas flow direction is configured to form an evaporator and a high-pressure economizer.
The eighth heat exchange panel unit N8 located eighth in the exhaust gas flow direction is configured to function as an intermediate pressure economizer and a high pressure economizer.

  Accordingly, the exhaust heat recovery boiler of the present embodiment generates low-pressure steam inside the low-pressure steam drum D1, and superheats the low-pressure steam of the low-pressure steam drum D1 with a low-pressure superheater to external heat consuming equipment. Supply, generate intermediate pressure steam inside the intermediate pressure steam drum D2, superheat the intermediate pressure steam in the intermediate pressure steam drum D2 with an intermediate pressure superheater, and supply it to an external heat consuming device; The high-pressure steam is generated inside the high-pressure steam drum D3, and the high-pressure steam in the high-pressure steam drum D3 is heated by a superheater for high-pressure steam and supplied to a steam turbine (not shown). ing.

  In other words, the exhaust heat recovery boiler of the present embodiment is equipped with a combined cycle power plant, and is a high-pressure superheated steam that drives a steam turbine (not shown) connected to rotate integrally with the gas turbine GT for power generation. In addition, medium pressure or low pressure superheated steam supplied to a heat consuming device such as a water heater is generated.

(Configuration of heat exchange panel)
As shown in FIG. 2, the heat exchange panel P includes a plurality of heat transfer tubes 3 (see FIG. 4) arranged along the tube axial direction of the upper header 1 and the lower header 2 positioned in parallel. It is comprised in the form connected between the header 1 and the lower header 2.
A heat transfer fin 3a such as a spiral plate is attached to the outer peripheral portion of the intermediate portion excluding the lower end and the upper end of the heat transfer tube 3 so as to improve the heat transfer efficiency.

As shown in FIGS. 3 and 4, in the present embodiment, the plurality of heat transfer tubes 3 arranged along the axial direction of the upper header 1 and the lower header 2 are arranged in the exhaust gas flow direction of the gas turbine GT. The upper side deviation state deviating toward the upper side and the lower side deviation state deviating toward the lower side in the exhaust gas flow direction are alternately installed along the tube axis direction.
Incidentally, in the present embodiment, about 80 heat transfer tubes 3 are arranged side by side along the tube axis direction.

  In addition, as shown in FIG. 3, although detailed illustration is abbreviate | omitted about the superheater of the 3rd heat exchange panel unit N3 and the superheater of the 4th heat exchange panel unit N4, upper pipe A plurality of heat transfer tubes 3 arranged along the axial direction of the header 1 and the lower header 2 are configured to be aligned in the same position in the exhaust gas flow direction of the gas turbine GT.

Further, as shown in FIG. 2, the lower header 2 is formed with a connection hole 4 into which the lower end portion of the heat transfer tube 3 is inserted, and the lower end portion of the heat transfer tube 3 is formed in the lower header 2. In the state inserted into the lower header 2, the peripheral portion of the connection hole 4 in the lower header 2 and the surface portion of the heat transfer tube 3 are welded, that is, connected to the lower header 2 by so-called insertion welding.
In addition, although detailed illustration is abbreviate | omitted, the upper end part of the heat exchanger tube 3 is also connected to the upper header 1 by insertion welding similarly to a lower end part.

  Incidentally, in this embodiment, the distance between the upper header 1 and the lower header 2 is about 30 m, and the upper header 1 and the lower header 2 have a diameter of about 200 mm and a wall thickness of 20 to 25 mm. The heat transfer tube 3 is configured using a pipe having a diameter of about 30 to 40 mm and a wall thickness of about 3 mm.

  As is apparent from the above description, the heat exchange panel P is disposed inside the boiler casing K in a state of being aligned in the exhaust gas flow direction of the gas turbine GT so as to form the heat exchange panel unit N. Become.

Specifically, the heat exchange panel P supports the upper header 1 in a suspended manner with respect to the ceiling portion of the boiler casing K, and supports the lower header 2 on an elastic telescopic cradle. It is provided in the form.
Since the structure for suspending and supporting the upper header 1 of the heat exchange panel P with respect to the ceiling portion of the boiler casing K and the structure for mounting and supporting the lower header 2 with an elastic telescopic cradle are well known, In the present embodiment, detailed description of the support configuration of the heat exchange panel P is omitted.

(Repair method of exhaust heat recovery boiler)
Next, a method for repairing the exhaust heat recovery boiler will be described in the case of repairing the three heat exchange panels P forming the high pressure economizer in the sixth heat exchange panel unit N6.
The heat exchange panel P in the other heat exchange panel unit N can be repaired in the same manner.

  As shown in FIG. 3, the three heat exchange panels P forming the high pressure economizer are located on the lower side of the exhaust gas flow direction of the sixth heat exchange panel unit N6. The repair work of the three heat exchange panels P that form the above is performed in the work space S on the lower side of the exhaust gas flow direction of the sixth heat exchange panel unit N6.

  Therefore, the work direction for the three heat exchange panels P forming the high-pressure economizer by the operator located in the work space S on the lower side of the exhaust gas flow direction of the sixth heat exchange panel unit N6 is the exhaust gas flow direction. The direction is from the lower side to the upstream side.

  Incidentally, whether or not it is necessary to repair the three heat exchange panels P forming the high pressure economizer in the sixth heat exchange panel unit N6 is determined based on the three heat exchange panels forming the high pressure economizer. Among the P, the thickness of the plurality of heat transfer tubes 3 of the heat exchange panel P that is the most inferior in the exhaust gas flow direction is measured by an operator located in the work space S using an ultrasonic sensor or the like, and the plurality of heat transfer tubes 3 are measured. When the thickness of any one of the heat transfer tubes 3 is equal to or less than the set reference value, it is determined that it is time to repair.

  Among the three heat exchange panels P forming the high-pressure economizer, the thickness of the heat transfer tube 3 of the heat exchange panel P that is the lowest side in the exhaust gas flow direction is set by, for example, flow accelerated corrosion When it becomes below the standard, it can be inferred that the thickness of the heat transfer tube 3 of the other heat exchange panel P is not less than the set standard value but is close to the set standard value. The three heat exchange panels P forming the high pressure economizer are repaired at once.

  Incidentally, although flow accelerated corrosion is exemplified here, erosion corrosion, pitting corrosion, intergranular corrosion, crevice corrosion, stress corrosion cracking, and the like can be cited as forms of corrosion.

  As shown in FIGS. 6 to 9, the repair method according to the present embodiment includes a replacement lower header 2 </ b> Z corresponding to the lower header 2 of the heat exchange panel P and a replacement target portion 3 </ b> W below the plurality of heat transfer tubes 3. A replacement panel portion PZ manufactured in a form including a replacement heat transfer tube portion 3Z corresponding to the above is prepared in advance.

  In other words, in a work place having a large work space such as a factory, for example, using a positioning jig or the like for manufacturing, a plurality of replacement heat transfer tube portions 3Z are inserted and welded to the replacement lower header 2Z to replace the replacement panel. The part PZ is manufactured and prepared in advance.

And as shown in FIG.6 and FIG.7, the some heat exchanger tube 3 of the heat exchange panel P is cut | disconnected in the state which cut | disconnects the exchange object part 3W, and the lower header 2 and the heat exchanger tube 3 of the heat exchange panel P are cut | disconnected. The replacement target part 3W is separated.
Thereafter, as shown in FIGS. 8 and 9, the upper end portion of the replacement heat transfer tube portion 3Z of the replacement panel portion PZ is welded to the lower end portion of the upper side tube portion 3U from which the replacement target portion 3W in the heat transfer tube 3 is cut off. Then, the replacement panel portion PZ is mounted on the heat exchange panel P.

  And in this embodiment, what repairs three heat exchange panels P which form a high pressure economizer among five heat exchange panels P arranged in close proximity along the exhaust gas flow direction. Therefore, specifically, it will be performed as follows.

That is, among the five heat exchange panels P arranged in close contact with each other in the sixth heat exchange panel unit N6, three heat exchange panels P heading from one end side to the other end side in the arrangement direction are exchanged heat exchange panels. P.
And as shown in FIG.6 and FIG.7, the other end side (upstream side of an exhaust gas flow direction) from the heat exchange panel P of the one end side (downstream side of an exhaust gas flow direction) of the heat exchange panels P of those exchange object To the heat exchange panel P, the plurality of heat transfer tubes 3 are sequentially cut into a state in which the replacement target portion 3W is cut off, and the lower header 2 of the heat exchange panel P and the replacement target portion 3W of the heat transfer tube 3 are separated. To do.

  Note that the heat exchange panel P on one end side in the arrangement direction is the heat exchange panel P located on the most downstream side in the exhaust gas flow direction, and the direction from one end side to the other end side corresponds to the above-described work direction. Direction.

  After separating the lower header 2 of the heat exchange panel P and the exchange target portion 3W of the heat transfer tube 3, as shown in FIGS. 8 and 9, the other end side of the three heat exchange panels P to be exchanged From the heat exchanging panel P toward the heat exchanging panel P on one end side, the upper pipe of the exchanged heat transfer tube portion 3Z of the exchange panel portion PZ is sequentially separated from the upper tube of the heat transfer tube 3 where the exchange target portion 3W is cut off. The replacement panel portion PZ is attached to the heat exchange panel P by welding to the lower end portion of the portion 3U.

And in this embodiment, the length of the exchange object part 3W of the heat exchanger tube 3 in the heat exchange panel P of three exchange object is set to the same length.
Therefore, since the length of the replacement heat transfer tube portion 3Z in the replacement panel portion PZ attached to each of the plurality of replacement target heat exchange panels P is the same, the replacement panel portion PZ is replaced with three replacement target portions. Since the heat exchange panel P can be shared, the replacement panel portion PZ having one specification is manufactured for the three heat exchange panels P to be exchanged.

  Incidentally, when separating the lower header 2 of the heat exchange panel P and the replacement target portion 3W of the heat transfer tube 3, as shown in FIGS. 6 and 7, the upper side located above the cut portion of the heat transfer tube 3 Of the heat transfer fins 3a in the tube portion 3U, the heat transfer fins 3a in the set range H (see FIG. 5) above the cut portion of the heat transfer tube 3 are removed.

  By removing the heat transfer fins 3a in this way, the upper end portion of the replacement heat transfer tube portion 3Z of the replacement panel portion PZ is changed to the lower end portion of the upper side tube portion 3U from which the replacement target portion 3W of the heat transfer tube 3 is separated. When welding, the heat transfer fins 3a can be prevented from getting in the way.

  The timing for removing the heat transfer fins 3a may be before the cutting process for cutting off the replacement target portion 3W of the heat transfer tube 3 but the cutting for cutting off the replacement target portion 3W of the heat transfer tube 3 is performed. It may be after processing.

(Summary of the first embodiment)
The exhaust heat recovery boiler repair method of the present embodiment corresponds to the replacement lower header 2Z corresponding to the lower header 2 of the heat exchange panel P and the replacement target portion 3W below the plurality of heat transfer tubes 3 in advance. Since the replacement panel portion PZ manufactured in the form including the replacement heat transfer tube portion 3Z is prepared and the replacement panel portion PZ is attached to the heat exchange panel P to be replaced, Simplification can be achieved.

  That is, when flow accelerated corrosion occurs in the lower portion of the heat transfer tube 3 and the heat exchange panel P is repaired, first, the plurality of heat transfer tubes 3 of the heat exchange panel P are connected to the lower side of the heat transfer tube 3. The replacement target portion 3W is cut off to separate the lower header 2 of the heat exchange panel P and the replacement target portion 3W of the heat transfer tube 3, and then the replacement heat transfer tube portion 3Z of the replacement panel portion PZ is separated. The replacement panel portion PZ is attached to the heat exchange panel P by welding the upper end portion to the lower end portion of the upper tube portion 3U from which the replacement target portion 3W of the heat transfer tube 3 is cut off.

  Therefore, when repairing the heat exchange panel P, the lower end portion of the lower portion of the heat transfer tube 3 (replacement target portion 3W) is separated from the lower header 2, and the lower end portion of the replacement heat transfer tube portion 3Z is set to the lower portion. Since the work of inserting and welding to the header 2 becomes unnecessary, the repair work of the heat exchange panel P can be easily performed.

  Incidentally, in order to manufacture the replacement panel portion PZ, the lower end portion of the replacement heat transfer tube portion 3Z is inserted and welded to the replacement lower header 2Z, but the replacement panel portion PZ is manufactured at the factory. Since it can be performed while using a positioning jig or the like in a wide space such as the inside, the work of inserting and welding the lower end portion of the replacement heat transfer tube portion 3Z to the replacement lower header 2Z can also be performed well.

  Further, in repairing the three heat exchange panels P forming the high pressure economizer in the sixth heat exchange panel unit N6, the length of the replacement target portion 3W of the heat transfer tube 3 in the three heat exchange panels P to be replaced Therefore, the length of the replacement heat transfer tube portion 3Z in the replacement panel portion PZ to be mounted on each of the three heat exchange panels P to be replaced is the same.

  Therefore, since the replacement panel portion PZ can be shared by the three heat exchange panels P to be replaced, the replacement panel portion PZ having one specification is manufactured for the three heat exchange panels P to be replaced. Therefore, the replacement panel portion PZ can be easily manufactured.

[Second Embodiment]
Next, although 2nd Embodiment is described, this 2nd Embodiment shows another embodiment of the repair method of a waste heat recovery boiler, Comprising: The specific structure of a waste heat recovery boiler is 1st Embodiment. Since it is the same, hereinafter, a different part from 1st Embodiment is explained in full detail, the same code | symbol is attached | subjected to the part same as 1st Embodiment, and detailed description is abbreviate | omitted.

  The repair method of the exhaust heat recovery boiler of the second embodiment will be described for the case of repairing the three heat exchange panels P forming the high pressure economizer in the sixth heat exchange panel unit N6, as in the first embodiment. To do.

  As shown in FIGS. 10 to 13, similarly to the first embodiment, the replacement lower header 2 </ b> Z corresponding to the lower header 2 of the heat exchange panel P and the replacement target portion 3 </ b> W below the plurality of heat transfer tubes 3 are provided. A replacement panel portion PZ manufactured in a form including a corresponding replacement heat transfer tube portion 3Z is prepared in advance, and this replacement panel portion PZ is attached to the heat exchange panel P to be replaced.

That is, as shown in FIGS. 10 and 11, the plurality of heat transfer tubes 3 of the heat exchange panel P are cut into a state in which the replacement target portion 3 </ b> W is cut off, and the lower header 2 and the heat transfer tubes 3 of the heat exchange panel P are cut. The replacement target part 3W is separated.
Thereafter, as shown in FIGS. 12 and 13, the upper end portion of the replacement heat transfer tube portion 3Z of the replacement panel portion PZ is welded to the lower end portion of the upper side tube portion 3U from which the replacement target portion 3W in the heat transfer tube 3 is cut off. Then, the replacement panel portion PZ is mounted on the heat exchange panel P.

  Also in the second embodiment, of the five heat exchange panels P arranged in close proximity along the exhaust gas flow direction, the three heat exchange panels P forming the high-pressure economizer are repaired. Therefore, among the five heat exchange panels P arranged in close contact with the sixth heat exchange panel unit N6, the three heat exchange panels P from the one end side to the other end side in the arrangement direction are to be exchanged. The heat exchange panel P is assumed.

  Then, as shown in FIGS. 10 and 11, the plurality of heat transfer tubes 3 sequentially from the heat exchange panel P on one end side to the heat exchange panel P on the other end side among the heat exchange panels P to be exchanged. Is cut into a state in which the replacement target portion 3W is cut off, and the lower header 2 of the heat exchange panel P and the replacement target portion 3W of the heat transfer tube 3 are separated.

  After separating the lower header 2 of the heat exchange panel P and the replacement target portion 3W of the heat transfer tube 3, as shown in FIGS. 12 and 13, the other end side of the three heat exchange panels P to be replaced From the heat exchange panel P toward the heat exchange panel P on one end side, the upper side pipe from which the exchange target part 3W in the heat transfer pipe 3 is separated from the upper end part of the exchange heat transfer pipe part 3Z of the exchange panel part PZ sequentially. The replacement panel portion PZ is attached to the heat exchange panel P by welding to the lower end portion of the portion 3U.

  And in this 2nd Embodiment, the heat exchange panel P of the exchange object among the heat transfer tubes 3 of the upper side deviation state and the heat transfer tubes 3 of the lower side deviation state in the heat exchange panel P to be exchanged is arranged. The length of the exchange target portion 3W of the heat transfer tube 3 that is one end side in the direction (downstream side in the exhaust gas flow direction) is set to the other end side in the arrangement direction of the heat exchange panels P to be exchanged (upstream side in the exhaust gas flow direction). It is set longer than the length of the replacement target portion 3W of the heat transfer tube 3 to be formed.

  In addition, the lengths of the exchange target portions 3W of the heat transfer tubes 3 in the upper side displacement state in the three heat exchange panels P to be exchanged are made the same, and the lower side deviations in the three heat exchange panels P to be exchanged The length of the replacement target portion 3W of the heat transfer tube 3 in the state is set to be the same.

(Summary of the second embodiment)
The repair method of the exhaust heat recovery boiler according to the second embodiment includes a plurality of replacement lower headers 2Z corresponding to the lower header 2 of the heat exchange panel P and a plurality of the same as the repair method of the exhaust heat recovery boiler according to the first embodiment. A replacement panel portion PZ manufactured in a form including a replacement heat transfer tube portion 3Z corresponding to the replacement target portion 3W on the lower side of the heat transfer tube 3 is prepared, and the replacement panel portion PZ prepared in advance is prepared. Since it is attached to the heat exchange panel P to be exchanged, the repair work can be facilitated.

  And in this 2nd Embodiment, in repairing three heat exchange panels P which form the high pressure economizer in 6th heat exchange panel unit N6, the upper side deviation state in heat exchange panel P of exchange object Among the heat transfer tubes 3 and the heat transfer tubes 3 in the lower-side deviation state, the heat transfer tubes 3 to be exchanged become one end side in the arrangement direction of the three heat exchange panels P to be exchanged (downstream in the exhaust gas flow direction). The length of the portion 3W is made longer than the length of the replacement target portion 3W of the heat transfer tube 3 which is the other end side in the arrangement direction of the three heat exchange panels P to be replaced (upstream side in the exhaust gas flow direction). Therefore, when the upper end portion of the replacement heat transfer tube portion 3Z of the replacement panel portion PZ is welded to the lower end portion of the upper tube portion 3U from which the replacement target portion 3W in the heat transfer tube 3 is cut, the welding work is performed. Can be improved.

  That is, when the upper end portion of the replacement heat transfer tube portion 3Z of the replacement panel portion PZ is welded to the lower end portion of the upper side tube portion 3U from which the replacement target portion 3W of the heat transfer tube 3 is cut, the replacement target in the heat transfer tube 3 is replaced. Since the height of the lower end portion of the upper tube portion 3U from which the portion 3W has been separated becomes different between the adjacent ones in the tube axis direction, the upper portion of the heat transfer tube 3 adjacent in the tube axis direction It is possible to improve the workability of the welding operation, such as welding the replacement heat transfer tube portion 3Z of the replacement panel portion PZ to the lower end portion simultaneously by another operator.

  Furthermore, in this 2nd Embodiment, the length of the replacement | exchange target part 3W of the heat exchanger tube 3 of the upper side deviation state in the heat exchange panel P of three replacement | exchange objects is the same, and heat exchange of three replacement | exchange objects Since the lengths of the replacement target portions 3W of the heat transfer tubes 3 in the lower side displacement state in the panel P are the same, three replacement panel portions PZ to be attached to each of the three replacement target heat exchange panels P are provided. Since the heat exchange panel P to be exchanged can be shared, it is only necessary to produce a replacement panel part PZ of one specification for the three heat exchange panels P to be exchanged. Becomes easier.

[Third Embodiment]
Next, although 3rd Embodiment is described, this 3rd Embodiment shows another embodiment of the repair method of a waste heat recovery boiler, Comprising: The specific structure of a waste heat recovery boiler is 1st Embodiment. Since it is the same, hereinafter, a different part from 1st Embodiment is explained in full detail, the same code | symbol is attached | subjected to the part same as 1st Embodiment, and detailed description is abbreviate | omitted.

  The repair method for the exhaust heat recovery boiler of the third embodiment will be described in the case of repairing the three heat exchange panels P forming the high-pressure economizer in the sixth heat exchange panel unit N6, as in the first embodiment. To do.

  As shown in FIGS. 14 to 17, similarly to the first embodiment, the replacement lower header 2 </ b> Z corresponding to the lower header 2 of the heat exchange panel P and the replacement target portion 3 </ b> W below the plurality of heat transfer tubes 3 are provided. A replacement panel portion PZ manufactured in a form including a corresponding replacement heat transfer tube portion 3Z is prepared in advance, and this replacement panel portion PZ is attached to the heat exchange panel P to be replaced.

That is, as shown in FIG.14 and FIG.15, the several heat exchanger tube 3 of the heat exchange panel P is cut | disconnected in the state which cut | disconnects the exchange object part 3W, and the lower header 2 and the heat exchanger tube 3 of the heat exchange panel P are cut | disconnected. The replacement target part 3W is separated.
Thereafter, as shown in FIGS. 16 and 17, the upper end portion of the replacement heat transfer tube portion 3Z of the replacement panel portion PZ is welded to the lower end portion of the upper side tube portion 3U from which the replacement target portion 3W in the heat transfer tube 3 is cut off. Then, the replacement panel portion PZ is mounted on the heat exchange panel P.

  Also in the third embodiment, of the five heat exchange panels P arranged in close proximity along the exhaust gas flow direction, the three heat exchange panels P forming the high-pressure economizer are repaired. Therefore, among the five heat exchange panels P arranged in close contact with the sixth heat exchange panel unit N6, the three heat exchange panels P from the one end side to the other end side in the arrangement direction are to be exchanged. The heat exchange panel P is assumed.

  And as shown in FIG.14 and FIG.15, several heat exchanger tube 3 is sequentially turned toward the heat exchange panel P of the other end side from the heat exchange panel P of the one end side among the heat exchange panels P of those exchange object. Is cut into a state in which the replacement target portion 3W is cut off, and the lower header 2 of the heat exchange panel P and the replacement target portion 3W of the heat transfer tube 3 are separated.

  After separating the lower header 2 of the heat exchange panel P and the exchange target portion 3W of the heat transfer tube 3, as shown in FIGS. 16 and 17, the other end of the three heat exchange panels P to be exchanged. From the heat exchanging panel P toward the heat exchanging panel P on one end side, the upper pipe of the exchanged heat transfer tube portion 3Z of the exchange panel portion PZ is sequentially separated from the upper tube of the heat transfer tube 3 where the exchange target portion 3W is cut off. The replacement panel portion PZ is attached to the heat exchange panel P by welding to the lower end portion of the portion 3U.

  In the third embodiment, the length of the replacement target portion 3W of the heat transfer tube 3 in the upper side displacement state in the heat exchange panel P to be replaced and the replacement target portion 3W of the heat transfer tube 3 in the lower side displacement state. Set to the same length.

  In addition, the length of the replacement target portion 3W of the heat transfer tube 3 is sequentially increased from the heat exchange panel P on one end side in the arrangement direction of the three heat exchange panels P to be replaced toward the heat exchange panel P on the other end side. To shorten.

(Summary of the third embodiment)
The repair method of the exhaust heat recovery boiler of the third embodiment includes a plurality of replacement lower headers 2Z corresponding to the lower header 2 of the heat exchange panel P and a plurality of repair methods, as in the repair method of the exhaust heat recovery boiler of the first embodiment. A replacement panel portion PZ manufactured in a form including a replacement heat transfer tube portion 3Z corresponding to the replacement target portion 3W on the lower side of the heat transfer tube 3 is prepared, and the replacement panel portion PZ prepared in advance is prepared. Since it is attached to the heat exchange panel P to be exchanged, the repair work can be facilitated.

  And in this 3rd Embodiment, in repairing three heat exchange panels P which form the high pressure economizer in 6th heat exchange panel unit N6, the upper side deviation state in heat exchange panel P of exchange object Since the length of the exchange target portion 3W of the heat transfer tube 3 and the length of the exchange target portion 3W of the lower heat transfer tube 3 are the same, the plurality of heat transfer tubes 3 of one heat exchange panel P have the same height. Since it should just cut | disconnect now, the operation | work which cut | disconnects the heat exchanger tube 3 of the heat exchange panel P of replacement | exchange object becomes easy.

  Moreover, the length of the replacement target portion 3W of the heat transfer tube 3 is sequentially increased from the heat exchange panel P on one end side in the arrangement direction of the three heat exchange panels P to be replaced toward the heat exchange panel P on the other end side. When the heat transfer tube 3 of the heat exchange panel P located on the inner side (the other end side) of the heat exchange panel P is cut after the heat transfer tube 3 of the heat exchange panel P on the one end side is cut. Since the cutting position is lower than the cutting position of the heat transfer tube 3 of the heat exchange panel P on one end side, the transfer of the heat exchange panel P located on the inner side (the other end side) of the heat exchange panel P on the one end side. When the heat tube 3 is cut, it is possible to avoid the heat transfer tube 3 of the heat exchange panel P located on one end side (the side where the work space S is present) from the heat exchange panel P to be cut. Of the heat exchange panel P located on the inner side (the other end side) of the heat exchange panel P Satisfactorily perform the task of cutting the pipe 3.

[Fourth Embodiment]
Next, although 4th Embodiment is described, this 4th Embodiment shows another embodiment of the repair method of a waste heat recovery boiler, Comprising: The specific structure of a waste heat recovery boiler is 1st Embodiment. Since it is the same, hereinafter, a different part from 1st Embodiment is explained in full detail, the same code | symbol is attached | subjected to the part same as 1st Embodiment, and detailed description is abbreviate | omitted.

  The repair method of the exhaust heat recovery boiler of the fourth embodiment will be described in the case where the three heat exchange panels P forming the high-pressure economizer in the sixth heat exchange panel unit N6 are repaired as in the first embodiment. To do.

In the fourth embodiment, as shown in FIGS. 18 and 19, of the plurality of heat transfer tubes 3 arranged in the tube axis direction, the connecting tube 5 connected to the lower header 2 in the tube axis direction. A plurality of heat transfer tubes 3 in a part of the range Q including the connection place are set as exchange target heat transfer tubes 3K.
That is, in the first embodiment, all of the plurality of heat transfer tubes 3 arranged in the tube axis direction are replaced at a time, but in the fourth embodiment, a plurality of the above-mentioned partial ranges Q are included. The heat transfer tube 3 is configured to be a replacement target heat transfer tube 3K.

  The lower header 2 is provided with a partition 6 at the center in the axial direction of the tube, and the connecting pipe 5 is connected to each of the one end portion 2R and the other end portion 2L. A pair of the above-described partial ranges Q exists.

That is, FIG. 19 schematically shows the flow form of the fluid while showing the state where the connecting pipe 5 is connected to the lower part of the lower header 2 of the three heat exchange panels P forming the high pressure economizer. The fluid from the other high pressure economizer is supplied to one of the pair of connecting pipes 5 connected to the lower header 2 adjacent to the work space S.
The fluid supplied to one of the pair of connecting pipes 5 flows to the upper header 1 through the one end portion 2R of the lower header 2 and the heat transfer pipe 3, and then the other of the heat transfer pipe 3 and the lower header 2 It flows to the other of the pair of connecting pipes 5 through the end portion 2L.

The fluid that has flowed to the other of the pair of connecting pipes 5 flows through the connecting pipe 5 to the lower header 2 of the next heat exchange panel P located on the side away from the work space S. Specifically, it flows to the other end portion 2L of the lower header 2.
The fluid that has flowed to the other end portion 2L of the lower header 2 flows to the upper header 1 through the heat transfer tube 3, and then flows to the one end portion 2R of the lower header 2 through the heat transfer tube 3.

The fluid that has flowed to the one end portion 2R of the lower header 2 flows to the lower header 2 of the heat exchange panel P that is located farthest from the work space S through the connecting tube 5 connected to the one end portion 2R. It will be. Specifically, it flows to one end side portion 2 </ b> R of the lower header 2.
The fluid that has flowed to the one end portion 2R of the lower header 2 flows to the upper header 1 through the heat transfer tube 3, and then flows to the other end portion 2L of the lower header 2 through the heat transfer tube 3.

Although not shown, the fluid that has flowed to the other end portion 2L of the lower header 2 flows to the heat exchange panel P that forms another high-pressure economizer through the connecting tube 5 connected to the other end portion 2L. Will do.
As described above, since the connecting pipe 5 is connected to each of the one end side portion 2R and the other end side portion 2L in the lower header 2, there is a pair of the partial ranges Q described above. It will be.

Incidentally, in this embodiment, the connection position of the connecting pipe 5 connected to the one end portion 2R of the lower header 2 of the three heat exchange panels P is, for example, 2 toward the side away from the work space S. At a distance corresponding to the installation distance of the heat transfer tubes 3 of the book, it is displaced to the center side of the lower header 2 (left side in FIG. 19).
Similarly, the connection position of the connecting tube 5 connected to the other end portion 2L of the lower header 2 of the three heat exchange panels P is, for example, two heat transfer tubes toward the side away from the work space S. 3 is displaced to the center side (right side in FIG. 19) of the lower header 2 at an interval corresponding to the installation distance 3.

  The above-mentioned partial range Q is determined corresponding to the existence range of the heat transfer tubes 3 in which the accelerated corrosion tends to occur on both the left and right sides from the connection portion of the connecting tube 5. For example, about 10 heat transfer tubes 3 are determined corresponding to the existence ranges on each of the left and right sides from the connection location. In FIG. 18 and FIG. 20, it is painted black. Similarly, in FIG. 19, in order to distinguish the heat transfer tube 3 that tends to cause flow accelerated corrosion from other heat transfer tubes 3, the heat transfer tube 3 that tends to cause flow accelerated corrosion is replaced with another heat transfer tube 3. In order to distinguish it from, it is indicated by a bold line.

  However, in this embodiment, since the three heat exchange panels P forming the high pressure economizer are repaired at once, a part of the range Q as the exchange target range is the above-described three heat exchange panels. This is determined in view of the connection position of the connecting pipe 5 in the exchange panel P.

  That is, for the one end side portion 2R of the lower header 2, the range on the right side of the connecting tube 5 connected to the lower header 2 adjacent to the work space S is set to a range where, for example, about 10 heat transfer tubes 3 exist. The above-mentioned partial range Q is determined in such a manner that the left side range of the connecting pipe 5 connected to the lower header 2 adjacent to the work space S is a range in which, for example, about 14 heat transfer pipes 3 are present.

  For the other end side portion 2L of the lower header 2, the range on the left side of the connecting tube 5 connected to the lower header 2 adjacent to the work space S is, for example, a range in which about 10 heat transfer tubes 3 exist. The above-mentioned partial range Q is determined in such a manner that the range on the right side of the connecting pipe 5 connected to the lower header 2 adjacent to the work space S is, for example, a range in which about 14 heat transfer pipes 3 are present.

In the repair method of the present embodiment, as shown in FIGS. 20 to 23, the replacement panel portion PZ includes the replacement heat transfer tube portion 3Z corresponding to the replacement target portion 3W in the replacement target heat transfer tube 3K, and the lower tube. It is created in a form including a replacement lower header portion 2z corresponding to the replacement target lower header portion 2K to which the replacement target heat transfer tube 3K is connected.
That is, a replacement panel portion PZ manufactured in a form including a plurality of replacement heat transfer tube portions 3Z and replacement lower header portions 2z is prepared in advance.

  Then, as shown in FIGS. 20 and 22, the exchange target heat transfer tube 3K among the plurality of heat transfer tubes 3 of the heat exchange panel P is cut into a state in which the exchange target portion 3W is cut off, and the exchange target portion 3W is separated. At that time, the replacement lower header portion 2K is cut from the lower header 2 and separated.

  After that, as shown in FIGS. 21 and 23, the upper end portion of the replacement heat transfer tube portion 3Z of the replacement panel portion PZ is used as the lower end of the upper tube portion 3U from which the replacement target portion 3W of the replacement target heat transfer tube 3K is separated. In addition, the end portion of the replacement lower header portion 2z is welded to the end portion of the remaining lower header portion 2N that remains after the replacement target lower header portion 2K in the lower header 2 is cut off. Thus, the replacement panel portion PZ is mounted on the heat exchange panel P.

  By the way, in the present embodiment, of the five heat exchange panels P arranged in close proximity along the exhaust gas flow direction, the three heat exchange panels P forming the high pressure economizer are repaired. Therefore, as in the first embodiment described above, the work of mounting the replacement panel portion PZ on the heat exchange panel P is performed for each of the three heat exchange panels P.

  In the present embodiment, as in the first embodiment, the lengths of the replacement target portions 3W of the heat transfer tubes 3 in the three heat exchange panels P to be replaced are set to the same length. Instead of this, the configuration of the second embodiment or the third embodiment may be adopted.

(Summary of the fourth embodiment)
The repair method for the exhaust heat recovery boiler of the fourth embodiment can facilitate the repair work in the same manner as the repair method for the exhaust heat recovery boiler of the first embodiment.

  In addition, the repair method of the exhaust heat recovery boiler of the fourth embodiment is the connection of the connecting pipe 5 connected to the lower header 2 in the tube axis direction among the plurality of heat transfer tubes 3 arranged in the tube axis direction. Since the plurality of heat transfer tubes 3 in a part of the range Q including the place are the heat transfer tubes 3K to be replaced, the repair work can be simplified, and the replacement panel portion PZ can be made inexpensive. Costs required for repair can be reduced.

[Another embodiment]
Next, another embodiment will be described.
(1) In the first to third embodiments described above, three heat exchange panels P among five heat exchange panels P arranged in close contact along the exhaust gas flow direction are replaced with the heat exchange panels P to be exchanged. However, the number of heat exchange panels P to be exchanged among the plurality of heat exchange panels P arranged closely in the exhaust gas flow direction can be variously changed.

  For example, among the plurality of heat exchange panels P arranged in close proximity along the exhaust gas flow direction, one heat exchange panel P on one end side may be the heat exchange panel P to be exchanged, and the exhaust gas flow direction All of the plurality of heat exchange panels P arranged in close contact with each other may be used as the heat exchange panel P to be exchanged.

(2) In said 1st-3rd embodiment, although the exhaust heat recovery boiler provided with nine heat exchange panel units N was illustrated, the specific structure of the exhaust heat recovery boiler which applies the repair method of this invention is as follows. Various changes can be made.

(3) In the first to third embodiments, the case where all of the plurality of heat exchange panels P are closely arranged in the exhaust gas flow direction to form the exchange panel unit N is exemplified. The repair method of the present invention can be applied even when some of the heat exchange panels P are provided as a single heat exchange panel P separated from the other heat exchange panels P. is there.

(4) In said 1st-3rd embodiment, the several heat exchanger tube 3 located in a line with the axial direction of the heat exchange panel P shifts to the upper side displacement state and exhaust gas flow which are displaced to the upper side of the exhaust gas flow direction. The heat exchange panel P provided in the form of being alternately installed along the axial direction of the pipe in the lower side displacement state that is displaced to the lower side of the direction is illustrated as an example of repair, but the heat exchange panel P The heat exchange panel P provided in a form in which the plurality of heat transfer tubes 3 arranged in the tube axis direction are installed in the same position in the exhaust gas flow direction can be repaired in the same manner.

(5) In repairing the plurality of heat exchange panels P arranged closely in the exhaust gas flow direction, the length of the replacement target portion 3W of the heat transfer tube 3 of each heat exchange panel P is the same as in the first to third embodiments. It is not limited to the length described in (1), and various changes can be made in consideration of the work situation and the like.

  The configuration disclosed in the above embodiment (including another embodiment, the same shall apply hereinafter) can be applied in combination with the configuration disclosed in the other embodiment, as long as no contradiction occurs. The embodiment disclosed in this specification is an exemplification, and the embodiment of the present invention is not limited to this. The embodiment can be appropriately modified without departing from the object of the present invention.

1 Upper header 2 Lower header 2K Replacement lower header portion 2N Remaining lower header portion 2Z Replacement lower header 2z Replacement lower header portion 3 Heat transfer tube 3K Replacement target heat transfer tube 3U Upper tube portion 3W Replacement target portion 3Z Replacement heat transfer tube part GT Gas turbine P Heat exchange panel PZ Replacement panel part

Claims (6)

A heat exchange panel in which a plurality of heat transfer tubes arranged along the axial direction of the upper header and the lower header located in parallel is connected between the upper header and the lower header is an exhaust gas of the gas turbine. A method for repairing a waste heat recovery boiler arranged in parallel in the flow direction,
A replacement panel portion manufactured in a form including a replacement lower header corresponding to the lower header of the heat exchange panel and a replacement heat transfer tube portion corresponding to a replacement target portion on the lower side of the plurality of heat transfer tubes in advance. Prepare
Cutting the plurality of heat transfer tubes of the heat exchange panel into a state in which the replacement target portion is cut off, and separating the lower header of the heat exchange panel and the replacement target portion of the heat transfer tube;
Thereafter, the upper end portion of the replacement heat transfer tube portion of the replacement panel portion is welded to the lower end portion of the upper side tube portion from which the replacement target portion of the heat transfer tube is cut off, and the replacement panel portion is subjected to the heat exchange. A method for repairing a waste heat recovery boiler, which is mounted on a panel. A plurality of the heat exchange panels are juxtaposed in close contact along the exhaust gas flow direction,
Among the plurality of heat exchange panels arranged in close proximity, a plurality of heat exchange panels heading from one end side to the other end side in the arrangement direction are used as heat exchange panels to be exchanged, and one end of the heat exchange panels to be exchanged A plurality of the heat transfer tubes are sequentially cut from the heat exchange panel on the side toward the heat exchange panel on the other end side so as to cut off the replacement target portion, and the lower header and the heat transfer of the heat exchange panel are cut off. Separating the replacement part of the heat pipe,
Then, from the heat exchange panel on the other end side among the plurality of heat exchange panels to be exchanged toward the heat exchange panel on the one end side, the upper end portion of the replacement heat transfer tube portion of the replacement panel portion is sequentially The exhaust heat recovery boiler according to claim 1, wherein the replacement panel portion is attached to the heat exchange panel by welding to a lower end portion of the upper side pipe portion from which the replacement target portion is separated in the heat transfer tube. Repair method.   The method for repairing an exhaust heat recovery boiler according to claim 2, wherein the lengths of the exchange target portions of the heat transfer tubes in the plurality of exchange target heat exchange panels are the same. A plurality of the heat transfer tubes arranged along the axial direction of the tube, an upper side displacement state in which the heat transfer tube is displaced toward the upper side in the exhaust gas flow direction and a lower side displacement state in which the heat transfer tube is displaced toward the lower side in the exhaust gas flow direction; Are provided in the form of being alternately installed along the tube axis direction,
Of the heat transfer tubes in the upper side deviation state and the heat transfer tubes in the lower side deviation state in the heat exchange panel to be exchanged, one end side in the arrangement direction of the plurality of heat exchange panels to be exchanged. The length of the exchange target part of the heat transfer tube is longer than the length of the exchange target part of the heat transfer tube that is the other end side in the arrangement direction of the plurality of heat exchange panels to be exchanged, and a plurality of the exchanges The length of the exchange target part of the heat transfer tube in the upper side deviation state in the target heat exchange panel is the same, and the replacement target of the heat transfer tube in the lower side deviation state in the plurality of heat exchange panels to be exchanged The method for repairing an exhaust heat recovery boiler according to claim 2, wherein the lengths of the portions are the same. A plurality of the heat transfer tubes arranged along the axial direction of the tube, an upper side displacement state in which the heat transfer tube is displaced toward the upper side in the exhaust gas flow direction and a lower side displacement state in which the heat transfer tube is displaced toward the lower side in the exhaust gas flow direction; Are provided in the form of being alternately installed along the tube axis direction,
The length of the exchange target part of the heat transfer tube in the upper side deviation state in the heat exchange panel to be exchanged is the same as the length of the exchange target part of the heat transfer tube in the lower side deviation state, and The length of the exchange target portion of the heat transfer tube is sequentially shortened from the heat exchange panel on one end side in the arrangement direction of the plurality of heat exchange panels to be exchanged toward the heat exchange panel on the other end side. The method for repairing an exhaust heat recovery boiler according to claim 2. Among the plurality of heat transfer tubes arranged in the tube axis direction, a plurality of heat transfer tubes in a partial range including a connection portion of the connecting tube in the tube axis direction are used as the heat transfer tubes to be replaced, and the replacement panel portion. Corresponds to the exchange target lower header portion to which the exchange target heat transfer tube is connected among the exchange heat transfer tube portion corresponding to the exchange subject portion in the exchange subject heat transfer tube and the lower header. Created in a form with a replacement lower header,
When separating the exchange target portion in the exchange target heat transfer tube of the heat transfer tubes, cutting the replacement target lower header portion from the lower header and separating,
When the replacement panel portion is attached to the heat exchange panel, the upper end portion of the replacement heat transfer tube portion is welded to the lower end portion of the upper tube portion from which the replacement target portion is separated in the replacement target heat transfer tube. In addition, the end of the replacement lower header portion is welded to the end portion of the remaining lower header portion where the replacement target lower header portion in the lower header is cut off and remains. The method for repairing an exhaust heat recovery boiler according to any one of claims 1 to 5.

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