JP2011027288A - Heat exchanger, and repair method of heat exchanger - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce the number of pieces of wholesome piping which has to be cut when repairing an economizer having a plurality of pieces of piping for heat exchange. <P>SOLUTION: The economizer 220 is composed by horizontally arranging piping groups 114, 115 comprising the plurality of pieces of piping for heat exchange carrying a refrigerant through interiors; and plurally laminating piping panels 200A, 200B, 200C, 200D in a fore and aft direction, comprised by connecting the pieces of piping composing the horizontal piping groups 114, 115 at upper parts. In the piping panels 200A, 200B, 200C positioned in the fore and aft direction, a lower part of one piping group 115 in the right or left of the front piping panel 200A, and the other piping group 114 of the rear piping panel 200B are connected by connecting piping. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a heat exchanger including a plurality of pipes such as a economizer of an exhaust heat recovery boiler.

  An exhaust heat recovery boiler is installed as a device for generating steam from the exhaust gas of a gas turbine by heat exchange. The exhaust heat recovery boiler is provided with a economizer composed of a plurality of panels connected so that a plurality of pipes through which the refrigerant flows in the vertical direction extends the exhaust gas between the pipes of the economizer, Heat exchange is performed between the exhaust gas and the refrigerant to generate steam, and electric power is generated using this steam (see, for example, Patent Document 1).

JP 2007-298245 A

  Here, the piping of the economizer may cause accelerated corrosion due to water passing through the inside, and inspection work and repair work are required. Conventionally, repair work of pipes for economizers has been performed by cutting the top and bottom of the corrosion area and connecting new pipes. At this time, since the piping of the economizer is densely packed, if corrosion occurs in the piping in the back, corrosion occurs on the front side of the piping where corrosion has occurred in order to secure a work space. Not cut the healthy piping. For this reason, work is troublesome, and piping for connecting to the cut portion is necessary, resulting in high costs.

  This invention is made in view of said problem, The objective is to reduce the healthy piping which must be cut | disconnected when repairing the heat exchanger which has several piping, such as a economizer. .

  The heat exchanger according to the present invention includes a first pipe group including a plurality of heat exchange pipes arranged in a horizontal direction and in which the supplied refrigerant flows from the lower side to the upper side. A plurality of piping panels formed in parallel in the front-rear direction are configured by a second piping group including a plurality of heat exchange pipes in which the refrigerant discharged from the one piping group flows downward from above. The plurality of piping panels are provided such that the first piping group is arranged in the front-rear direction.

  Further, in the heat exchanger repair method of the present invention, a pipe group composed of a plurality of heat exchange pipes through which the refrigerant flows is arranged on the left and right sides, and the pipes constituting these left and right pipe groups are connected at the upper part. A plurality of pipe panels stacked in the front-rear direction, and the pipe panels positioned in the front-rear direction are heat exchangers in which the lower part of either the left or right pipe group of the front and rear pipe panels is connected by a connection pipe In the repair method, the connecting pipe is removed, and in the piping panel located at the front and back, the lower part of either the left or right piping group of the front piping panel and the other piping group of the rear piping panel It is characterized in that it is newly connected by connection piping.

  According to the present invention, on either the left or right side of the heat exchanger, the piping group in which the refrigerant flows from the lower side to the upper side where corrosion is likely to occur is located side by side, and the other side where corrosion is unlikely to occur. The pipe group in which the refrigerant flows from above to below is positioned side by side. Thereby, the occurrence of corrosion concentrates on the pipe on one side of the heat exchanger, and the corrosion on the other side of the pipe hardly occurs, so that it is possible to reduce cutting of a healthy pipe. In addition, the concentration of the pipes that are likely to cause corrosion makes it possible to repair a plurality of pipes at the time of a single repair operation, thereby reducing the number of healthy pipes to be cut.

It is a figure which shows the structure of a waste heat recovery boiler. It is a figure which shows the detailed structure of the low pressure side economizer used conventionally, (A) is a front view, (B) is II sectional drawing in (A), (C) is in (A). It is II-II sectional drawing. It is a block diagram which shows the structure of a low voltage | pressure side economizer. It is an expanded sectional view of the piping panel structure which comprises a low voltage | pressure side economizer. It is a figure which shows the structure of the economizer of this embodiment. It is a figure for demonstrating the determination method of the cutting position of piping. It is a figure for demonstrating the method of reusing and connecting the cut piping.

Hereinafter, one embodiment of a heat exchanger of the present invention is described in detail, referring to drawings.
FIG. 1 is a diagram illustrating a configuration of an exhaust heat recovery boiler 10. As shown in the figure, the exhaust heat recovery boiler 10 includes a low-pressure side economizer 20, a low-pressure side evaporator 21, a high-pressure side economizer 30, and a high-pressure side evaporator 31 provided in the flue 60, The low pressure side drum 22, the high pressure side drum 32, the superheater 40, the low pressure side pump 50, and the high pressure side pump 51 provided outside the flue 60 are configured.

  In the exhaust heat recovery boiler 10, combustion exhaust gas is supplied into the flue 60, and along the flow of the exhaust gas, the superheater 40, the high-pressure side evaporator 31, the high-pressure side economizer 30, the low-pressure side evaporator 21, and the low-pressure side node. They are arranged in the order of the charcoal units 20. The heat of the high-temperature exhaust gas discharged from the gas turbine is exchanged with water flowing in the superheater 40, the high-pressure side evaporator 31, the high-pressure side economizer 30, the low-pressure side evaporator 21, and the low-pressure side economizer 20. Heat exchange takes place between them. The detailed configuration of the low-pressure side economizer 20 will be described in detail later.

  The water pumped from the low-pressure side pump 50 is heated by the exhaust gas in the low-pressure side economizer 20 and sent to the low-pressure side evaporator 21, and is heated by the exhaust gas in the low-pressure side evaporator 21 to generate water vapor. Then, the water vapor generated in the low-pressure side evaporator 21 is sent to the low-pressure side drum 22, the water vapor is separated in the low-pressure side drum 22, and the separated water vapor is sent to the turbine.

  The water pumped from the high-pressure side pump 51 is heated by the exhaust gas in the high-pressure side economizer 30 and sent to the high-pressure side evaporator 31, and is heated by the exhaust gas in the high-pressure side evaporator 31 to generate water vapor. . The water vapor generated in the high pressure side evaporator 31 is sent to the high pressure side drum 32, the water vapor is separated in the high pressure side drum 32, and the separated water vapor is superheated by the superheater 40 and sent to the turbine.

  2A and 2B are diagrams showing a detailed structure of a low-pressure side economizer 20 that has been conventionally used. FIG. 2A is a front view, FIG. 2B is a cross-sectional view taken along line II in FIG. These are II-II sectional drawings in (A). FIG. 3 is a configuration diagram showing a configuration of the low-pressure side economizer 20, and FIG. 4 is an enlarged cross-sectional view of a piping panel structure 100A that constitutes the low-pressure economizer 20. As shown in FIG. 3, the first to fourth panel structures 100A to 100D are arranged in two rows on the left and right, but only one is shown in FIGS. Moreover, since the high-pressure side economizer 30 has the same configuration as the low-pressure side economizer 20, the description thereof is omitted.

As shown in FIGS. 2 and 3, the low-pressure side economizer 20 is formed by laminating first to fourth panel structures 100 </ b> A to 100 </ b> D.
The first to third panel structures 100A to 100C include first and second pipe groups 114 and 115 including a plurality of pipes 104 and 105, an upper pipe 101, and first and second lower pipes 102 and 103. It consists of. As shown in FIG. 4, the pipes 104 constituting the pipe groups 114 and 115 are arranged in a plurality of rows in the depth direction (three rows in the present embodiment) and a plurality of rows in the horizontal direction. The upper ends of the plurality of pipes 104 and 105 constituting the pipe groups 114 and 115 are connected to the upper pipe 101. The lower ends of the plurality of pipes 104 constituting the first pipe group 114 are connected to the first lower pipe 102, and the lower ends of the plurality of pipes 105 constituting the second pipe group 115 are the second lower pipe 103. It is connected to the. With this configuration, the water supplied to the first lower pipe 102 flows through the pipe 104 of the first pipe group 114 from the lower side to the upper side, passes through the upper pipe 101, and passes through the pipe 105 of the second pipe group 115. It flows from above to below and is discharged from the second lower pipe 103.

  The fourth panel structure 100 </ b> D includes a pipe group 123 including a plurality of pipes 124, an upper pipe 122 to which the upper end and the lower end of the pipe 124 of the pipe group 123 are connected, and a lower pipe 121. With this configuration, the water supplied to the lower pipe 121 flows through the pipe 124 of the pipe group 123 from below to the upper pipe 122.

  As shown in FIG. 3, the first panel structure 100 </ b> A and the third panel structure 100 </ b> C are provided such that the first piping group 114 is positioned on the outer side and the second piping group 115 is positioned on the center side. In the panel structure 100B, the second pipe group 115 is provided on the outer side, and the first pipe group 114 is provided on the center side. As shown in FIG. 3, the second (center side) lower pipe 103 of the first panel structure 100A is connected to the first (center side) lower pipe 102 of the second panel structure 100B. 130 is connected. The second (outer) lower pipe 103 of the second panel structure 100B is connected to the first (outer) lower pipe 102 of the third panel structure 100C via a connection pipe 130. The first (center side) lower pipe 103 of the third panel structure 100C is connected to the lower pipe 121 of the fourth panel structure 100D via a connection pipe 130. For this reason, on the outer side and the center side of the economizer 20, the first pipe group 114 in which water flows from the lower side to the upper side in the pipe 104 and the water flows from the upper side to the lower side in the pipe 105. The second pipe groups 115 are alternately arranged in the front-rear direction.

  With this configuration, the water supplied to the first lower pipe 102 of the first panel structure 100A flows through the pipe groups 114, 115, and 123 of the first to fourth panel structures 100A to 100D, and the fourth panel. It is discharged from the upper pipe 112 of the structure 100D. At this time, the exhaust gas circulates between the piping groups 114, 115, and 123 constituting the first to fourth panel structures 100A to 100D, and between the exhaust gas and the water that circulates inside the pipings 104, 105, and 124. Heat exchange takes place and the water is heated.

  Here, the water flowing through the lower pipes 102 and 121 is sent to the lower part of the pipes 104 and 124 constituting the pipe groups 114 and 123 to which the first lower pipe 102 and the lower pipe 121 are connected. A strong pressure is applied and the flow is disturbed. In such a place where the flow is disturbed, for example, Hiromi Shiihara and four others, “About erosion / corrosion thinning due to flow accelerated corrosion of marine steam plant piping”, “2. Mechanism of accelerated flow corrosion”, [ online], Japan Maritime Association, [March 30, 2009 search], Internet <URL: http://www.classnk.or.jp/hp/ja/activities/rd/H17_05.pdf> As shown, flow corrosion acceleration is likely to occur. For this reason, flow corrosion acceleration tends to occur in the lower part of the pipes 104 and 124 constituting the pipe groups 114 and 123 to which the lower pipes 102 and 121 are connected.

  Here, in the conventional economizer 20 as described above, the first pipe group 114 in which water flows in the pipe 104 from below to above and the water in which the water flows in the pipe 105 from above to below. The two pipe groups 115 are alternately arranged in the front-rear direction. For this reason, a sound pipe 105 that is not corroded is positioned on the front side of the corroded pipe 104, and the sound pipe 105 must be cut when repairing the corroded portion of the pipe 104. There were many cases.

In view of the above points, the inventors of the present application set the configuration of the economizer as described below.
FIG. 5 is a diagram illustrating a configuration of the economizer 220 of the present embodiment. As shown in the figure, in the economizer 220 of the present embodiment, all of the first to third panel structures 200A, 200B, and 200C have a first pipe group in which water flows from the bottom upward. 114 is provided on the outer side, and the second piping group 115 is provided on the center side. The water supplied to the economizer 220 is supplied to the first (outside) lower pipe 102 of the first panel structure 200A. The second (center side) lower pipe 103 of the first panel structure 200A and the first (outside) lower pipe 102 of the second panel structure 200B are connected by a pipe, and the second panel structure 200B Two (center side) lower pipes 103 are connected to the first (outside) lower pipes 102 of the third panel structure 200C by pipes. Further, the second (center side) lower pipe 103 of the third panel structure 200C and the lower pipe 121 of the fourth panel structure 200D are connected by a pipe.

  With this configuration, the first pipe group 114 composed of a plurality of pipes 104 through which water flows from below to above is arranged in the front-rear direction, and a plurality of water flows from the top to the bottom in the interior. The second piping group 115 including the piping 105 is arranged in the front-rear direction on the center side.

  Hereinafter, the repair method of the economizer 220 of this embodiment is demonstrated. In addition, although the following description demonstrates the case where the low voltage | pressure side economizer 20 is repaired, the high voltage | pressure side economizer 30 can also be repaired similarly.

  First, a fiberscope is inserted into the pipes 104, 105, and 124 of the pipe groups 114, 115, and 123 of the panel structures 200A to 200D, and the presence or absence of corrosion inside the pipes 104, 105, and 124 is confirmed. Here, as described above, since the first pipe group 114 that is likely to be corroded is arranged side by side on the outside, the first pipe group 114 arranged on the outside causes many corrosions, Corrosion hardly occurs in the second piping group arranged inside. Therefore, in the following description, a case where corrosion is confirmed in the pipe 104 on the back side of the pipe group 114 of the second panel structure 200B will be described.

When corrosion is confirmed in the pipe 104 as described above, repair work is performed.
In performing the repair work, first, the pipe 104 in which the occurrence of corrosion has been confirmed and the cutting position of the pipe 104 that becomes an obstacle to the cutting work of the pipe 104 are determined. FIG. 6 is a diagram for explaining a method for determining the cutting position of the pipes 104 and 105. As shown in FIG. 6, when corrosion occurs in the back side pipe 104, the pipe 104 on the near side of the pipe 104 in which corrosion has occurred must be cut. However, in this embodiment, the panel structures 200 </ b> A to 200 </ b> D are arranged so that the first pipe group 114 that is likely to be corroded is arranged in the front-rear direction, and thus the second pipe group 115 that is not corroded. There is no need to cut off. In addition, when corrosion occurs in the plurality of pipes 104, the pipes 104 in which corrosion has occurred are located in the vicinity, so that the number of pipes to be cut can be reduced.

  As shown by broken lines in FIG. 6, the cutting position of the pipe 104 where corrosion has occurred is set above and below the corroded portion, and the cutting position below each pipe 104 that is symmetrical to the cutting is the pipe 104 where corrosion has occurred. The upper cutting position is set to the same height as the cutting position, and the upper cutting position is gradually increased from the back toward the front. Then, each pipe 104 is cut at the determined position. At this time, the upper cut surface of each pipe 104 is horizontally cut so as to be stepped.

  Next, a healthy pipe is connected to the portion where the pipe 104 is cut. Here, among the cut pipes 104, pipes cut in order to secure work spaces other than the pipes 104 where corrosion has occurred are sound and can be reused, so work spaces are secured in the cut parts. Therefore, the cut pipe 104 can be used as a healthy pipe.

FIG. 7 is a diagram for explaining a method of reusing and connecting the cut pipe 300. When the cut pipe 300 is reused, the length is somewhat shortened because finishing is performed so that the upper end and the lower end can be connected. Therefore, as shown in FIG. 7, a cut pipe 300 in the front row is used as the pipe 310 connected to the cut portion. And the pipe | tube 310 which cut | disconnected the row | line | column ahead one row | line | column is processed to the length which fits the cut | disconnected part, and the processed piping 300 is connected. At this time, the lower cutting position of each pipe 104 is set to a certain height, and the upper cutting position is determined so as to gradually increase from the back toward the front, so that the work space expands toward the front side. Therefore, connection work can be easily performed.
By the above process, the economizer 220 can be repaired.

According to the present embodiment, the following effects can be obtained.
In the first to third panel structures 200A, 200B, and 200C, the first pipe group 114 that easily corrodes is arranged in the front-rear direction, and the second pipe group 115 that hardly corrodes is arranged in the front-rear direction. Therefore, when the pipe 104 of the first pipe group 114 is repaired, the repair work can be performed without cutting the pipe 105 of the second pipe group 115 that is unlikely to cause corrosion.

  Even when the plurality of pipes 104 are corroded, the corroded pipes 104 are located near the first pipe group 114 that is likely to be corroded. Thus, the number of pipes 104 that need to be cut in one repair operation can be reduced.

  In the present embodiment, all of the first to third panel structures 200A, 200B, and 200C are previously provided with the first piping group 114 that is likely to be corroded outside and the second piping that is unlikely to corrode. Although the economizer 220 provided so that the group 115 is located on the center side has been described, the present invention is not limited to this, and the conventional economizer 20 described with reference to FIG. A configuration of the economizer 220 may be used.

  That is, the pipe connecting the second (center side in the figure) lower pipe 103 of the first panel structure 100A and the first (center side in the figure) lower pipe 102 of the second panel structure is removed. The lower piping 103 on the center side in the drawing of the first panel structure 100A and the lower piping 102 on the outer side in the drawing of the second panel structure 100B are connected by piping. Further, the pipe connecting the second (outside in the figure) lower pipe 103 of the second panel structure 100B and the first (outside in the figure) lower pipe 102 of the third panel structure 100C is removed, A lower pipe 102 on the center side in the drawing of the second panel structure 100B is connected to a lower pipe 102 on the outer side in the drawing of the third panel structure 100C. Thereby, it becomes the structure similar to the economizer 20 with reference to FIG. 5, and the inspection and repair after the next time can be performed easily.

  In the present embodiment, as shown in FIG. 5, the first piping group 114 that is likely to corrode water from the bottom to the top is disposed on the outside, and the second piping group 115 is disposed on the inside. However, the present invention is not limited to this, and the second piping group 115 may be arranged outside and the first piping group arranged inside.

  Moreover, although this embodiment demonstrated the case where the 1st-4th panel structure 200A-200D was located in a line on the left and right, it is not restricted to this. The present invention can be applied even when only one row or three or more rows are arranged.

  Moreover, although this embodiment demonstrated the case where the four panel structures 200A-200D were arrange | positioned so that it might rank with the front-back direction, it is not restricted to this, The heat | fever which two or more panel structures line up with the front-back direction. The present invention can be applied to any exchanger.

10 boiler 20 (low pressure side) economizer 21 low pressure evaporator 22 low pressure drum 30 high pressure economizer 31 high pressure evaporator 32 high pressure drum 40 superheater 50 low pressure pump 51 high pressure pump 60 flue 100A, 100B, 100C, 100D Panel structure 101, 112, 122 Upper piping 102 First lower piping 103 Second lower piping 104, 105 Piping 114, 115, 123 Piping group 121 Lower piping 122 Upper piping 124 Piping 130 Connection piping 200A, 200B, 200C, 200D Panel structure 220

Claims (2)

A first refrigerant group composed of a plurality of heat exchange pipes, in which the supplied refrigerant is arranged in the lateral direction and flows from the lower side to the upper side, is discharged from the first pipe group. A heat exchanger in which a plurality of pipe panels configured by a plurality of pipes for heat exchange, in which a refrigerant flows from the upper side to the lower side, are arranged in parallel in the front-rear direction. ,
The heat exchanger according to claim 1, wherein the plurality of piping panels are provided so that the first piping group is arranged in the front-rear direction. A pipe group consisting of a plurality of heat exchange pipes through which refrigerant flows inside is arranged on the left and right, and a plurality of pipe panels are stacked in the front-rear direction. The pipe panels positioned in the front and rear are repair methods for a heat exchanger in which the lower part of either the left or right pipe group of the front and rear pipe panels is connected by a connection pipe,
Removing the connecting pipe,
The heat exchange characterized by connecting the lower part of either the left or right piping group of the front piping panel and the other piping group of the rear piping panel with a new connecting pipe in the piping panel positioned at the front and rear. How to repair the vessel.