JP7220992B2 - Heat transfer tube support structure and heat transfer tube support method - Google Patents

Description

TECHNICAL FIELD The present invention relates to a support structure for heat transfer tubes arranged in a staggered manner in a heat transfer tube panel provided in an exhaust heat recovery boiler or the like, and a support method for such heat transfer tubes.

Combined cycle power plants, which are attracting attention as part of high-efficiency power generation, first generate power with a gas turbine, and recover the heat in the exhaust gas emitted from the gas turbine in a heat recovery steam generator (HRSG). The steam generated by the recovery boiler drives a steam turbine to generate electricity. This combined power plant can simultaneously generate power with gas turbines and steam turbines, so power generation efficiency is high and gas turbines have excellent load responsiveness. There is also the advantage of being able to

In this type of combined cycle power plant, heat exchangers such as a superheater, an evaporator, and an economizer are generally arranged in the heat recovery boiler for recovering the heat of exhaust gas from the gas turbine. A denitration device is arranged to denitrate the exhaust gas. The heat exchanger consists of heat transfer tube panels in which a large number of heat transfer tubes are arranged in a zigzag pattern. Hot tubes are widely used.

In the so-called horizontal heat recovery boiler, which is configured so that the exhaust gas flows horizontally through the heat transfer tube panel, the duct height is 20m or more due to the increase in size of the boiler due to the increase in size of the gas turbine. The length of the internal finned heat transfer tubes is correspondingly long.

Finned heat transfer tubes are known to vibrate due to fluid force of exhaust gas, Karman vortices generated in the wake of the finned heat transfer tubes, and the like. The fins of the heat transfer tubes are easily damaged by vibration. Therefore, conventionally, heat transfer tubes with fins arranged in a staggered manner are bundled in the horizontal direction by support members, and these support members are provided in a plurality of stages at predetermined intervals in the vertical direction of the heat transfer tube panel, thereby suppressing the vibration of the heat transfer tubes with fins. Techniques for suppressing this have been proposed.

For example, in Patent Document 1, heat transfer tubes with fins arranged in a staggered manner are supported by a plate-like support member inserted between the fins, and a connecting plate is inserted into a gap between the heat transfer tubes with fins in an oblique direction. , a heat transfer tube support structure in which the rigidity of the entire plurality of heat transfer tube panels is increased by fixing both ends of the connecting plate to the support members of the heat transfer tube panels adjacent in the front-rear direction along the flow direction of the exhaust gas. is described.

In addition, in Patent Document 2, heat transfer tubes with fins arranged in a staggered manner are supported by honeycomb-shaped support members, and several heat transfer tubes with fins located at both ends in the horizontal direction are supported by short reinforcing support members. A heat transfer tube support that reduces the vibration displacement of the heat transfer tube panel by connecting the support member and the reinforcing support member with a gate-shaped anti-opening plate that is supported and inserted into the diagonal gap of the heat transfer tube with fins. structure is described.

Japanese Patent No. 2857440 JP 2013-57468 A

By the way, in recent gas turbine specifications, the exhaust gas that reaches the heat recovery steam generator is hot, has a high flow velocity, and is accompanied by swirling. There is an increased possibility of damage to the support members that bundle the heat tubes in the horizontal direction and damage to the heat transfer tube fins.

However, in the heat transfer tube support structure described in Patent Document 1, a connecting plate is inserted into a diagonal gap between heat transfer tubes with fins positioned at both ends in the horizontal direction, and both ends of the connecting plate are attached to each heat transfer tube panel. It is a technique to increase the rigidity of the panel by fixing it to the support members. Although the connecting plate increases the rigidity of both ends of the support member to some extent, it does not increase the rigidity of the support member as a whole. And it was difficult to suppress damage to the heat transfer tube fins over the entire range.

Further, in the heat transfer tube support structure described in Patent Document 2, by adding a reinforcing support member and making the width of both end sides of the support member wider than the central portion, three vibration systems (panel left end vibration system, It is a technology to reduce the vibration displacement of the heat transfer tube panel by using the phase difference between the vibration system at the center of the panel and the vibration system at the right end of the panel. This is to prevent the separation of the reinforcing support member and the support member, and the opening prevention plate does not increase the rigidity of the support member as a whole. It has been difficult to suppress over time.

SUMMARY OF THE INVENTION The present invention has been made in view of the actual situation of the prior art, and an object thereof is to be able to suppress damage to support members and damage to heat-conducting tube fins caused by vibration of heat-conducting tube panels over the entire range. Another object of the present invention is to provide a heat transfer tube support structure, and to provide a method for supporting such a heat transfer tube support structure.

In order to achieve the above object, a typical present invention comprises a heat transfer tube panel in which a plurality of heat transfer tubes extending in the vertical direction are arranged in a zigzag pattern, and a support member for bundling the heat transfer tubes in the horizontal direction, and the support In a heat transfer tube support structure in which members are provided in a plurality of stages at predetermined intervals in the vertical direction of the heat transfer tube panel , a first reinforcing plate obliquely arranged in a gap between the plurality of heat transfer tubes; A second reinforcing plate obliquely arranged in the gap so as to cross the first reinforcing plate, and one end sides of each of the first reinforcing plate and the second reinforcing plate are fixed to the support member. and a connecting member, wherein the heat transfer tube is a finned heat transfer tube having fins attached to the outer peripheral portion, and a cylindrical protective member surrounding the finned heat transfer tube, wherein the protective member is the support member. and the protective member is divided into upper and lower parts with the support member interposed therebetween, and the mounting pieces form a pair of upper and lower structures.

According to the present invention, damage to the support member and damage to the heat transfer tube fins due to vibration of the heat transfer tube panel can be suppressed over the entire range. Problems, configurations, and effects other than those described above will be clarified by the following description of the embodiments.

1 is an explanatory diagram showing a schematic system of a combined cycle power plant; FIG. 1 is an external perspective view of an exhaust heat recovery boiler; FIG. FIG. 3 is a side view showing the internal structure of the inlet portion of the heat recovery boiler; FIG. 3 is a perspective view of a heat transfer tube panel provided in the heat recovery boiler. FIG. 4 is a cross-sectional view of a heat transfer tube panel; 1 is a perspective view of a heat transfer tube support structure according to an embodiment of the present invention; FIG. It is a front view of the heat transfer tube support structure. It is a top view of this heat-transfer-tube support structure. FIG. 4 is an explanatory diagram of the main part of the heat transfer tube support structure; It is explanatory drawing which shows the assembly procedure of this heat-transfer-tube support structure. FIG. 5 is a perspective view of a heat transfer tube support structure according to another embodiment of the present invention; FIG. 5 is a perspective view of a heat transfer tube support structure according to another embodiment of the present invention;

Embodiments of the present invention will be described below with reference to FIGS. 1 to 12. FIG.

FIG. 1 is an explanatory diagram showing a schematic system of a combined cycle power plant. As shown in FIG. 1, a high-temperature, high-speed exhaust gas 11 from a gas turbine 1 passes through a superheater 3, a first evaporator 4, a denitrification device 5, and a superheater 3 installed in a duct 12 of a heat recovery steam generator (HRSG) 2. The second evaporator 6 and the economizer 7 are brought into contact with each other in order for heat exchange. Further, water containing steam from the first evaporator 4 and the second evaporator 6 is sent to the steam separation drum 8 from the pipeline 9a and the pipeline 9b, respectively, and the steam separated from the steam separation drum 8 is , and after being further superheated by the superheater 3 via the saturated steam pipe 10 , it is utilized as superheated steam that drives the steam turbine 14 via the main steam pipe 13 .

The steam used in the steam turbine 14 is returned to water W in the condenser 15, circulated to the economizer 7 by the feedwater pump 17 arranged in the feedwater pipeline 16, and discharged from the gas turbine 1 in the economizer 7. is preheated from exhaust gas 11 and supplied to steam separation drum 8 . The water in the steam separation drum 8 descends through the downcomer 18 and is introduced via lines 19a, 19b into the evaporators 4, 6 and then back into the steam separation drum 8 via lines 9a, 9b. . A turbine bypass pipe 20 connected to the main steam pipe 13 may bypass the steam turbine 14 and guide the steam directly to the condenser 15 . Also provided are a steam turbine control valve 21 for adjusting the flow rate of steam to the steam turbine 14, a turbine bypass valve 22 for adjusting the steam bypass amount by supplying steam to the steam turbine 14, and a damper 23 for the duct 12. there is

The above description is an overview of the flow of the high-temperature and high-speed exhaust gas 11, feed water, and steam in the combined power plant. Heat exchangers such as the vessels 4 and 6 and the economizer 7 are incorporated, and a denitrification device 5 is arranged to recover exhaust heat of the exhaust gas 11 and denitrify the exhaust gas 11 .

FIG. 2 is an external perspective view of the heat recovery boiler 2, with a part of the duct 12 cut away so that the internal structure can be seen. FIG. 3 is a side view showing the internal structure of the inlet portion of the heat recovery boiler 2. As shown in FIG.

As shown in FIGS. 2 and 3, the duct 12 of the heat recovery boiler 2 is supported on the ground 25 via a frame 24, and the high-temperature, high-speed exhaust gas 11 from the gas turbine 1 flows into the duct 12. do. The exhaust gas 11 that has flowed into the duct 12 is heat-absorbed by the heat transfer tube panel 30 , and the relatively low-temperature gas is discharged from the chimney 26 to the outside of the duct 12 . The heat transfer tube panel 30 is a heat exchanger constituting a heat transfer surface of the superheater 3, the first evaporator 4, the second evaporator 6, the economizer 7, etc. shown in FIG. supported downwards. Since the high-temperature and high-speed exhaust gas 11 acts on the heat transfer tube panel 30, the heat transfer tube panel 30 vibrates in the longitudinal direction and the lateral direction with respect to the gas flow.

4 is a perspective view of the heat transfer tube panel 30, and FIG. 5 is a cross-sectional view of the heat transfer tube panel 30. As shown in FIG. As shown in FIGS. 4 and 5, the heat transfer tube panel 30 has a large number of heat transfer tubes 31 connected between the upper and lower headers 27, and the heat from the exhaust gas 11 is absorbed by the outer peripheral surface of the heat transfer tubes 31. A fin 32 is helically wrapped to facilitate In this embodiment, three heat transfer tube panels 30 are formed as one unit with the panel surface facing the direction orthogonal to the gas flow, and a plurality of such units are arranged side by side.

Heat transfer tubes 31 with fins 32 (hereinafter referred to as finned heat transfer tubes) are arranged in three rows in a staggered manner, and each finned heat transfer tube 31 is horizontally bundled using a honeycomb support 33 and a horizontal support 34. there is The honeycomb support 33 is formed by combining corrugated plates arranged so as to sandwich the fins 32 and integrating them into a honeycomb shape. It is The horizontal support 34 is welded to the periphery of the honeycomb support 33 , and the honeycomb support 33 and the horizontal support 34 constitute one support member 35 . The support members 35 are provided in a plurality of stages (for example, 9 stages) at predetermined intervals in the vertical direction of the heat transfer tube panel 30, and these support members 35 allow the heat transfer tubes 31 with fins of, for example, 33 x 3 rows to be vertically arranged. are bundled horizontally.

The heat transfer tube panels 30 bundled by the support member 35 in this manner are installed in the duct 12 of the heat recovery steam generator 2. As described above, the heat transfer tube panels 30 are exposed to the high-temperature, high-speed exhaust gas 11. Therefore, the heat transfer tube panel 30 vibrates violently in the front-rear direction and the left-right direction with respect to the gas flow, which may damage the support members 35 and the fins 32 . As a countermeasure structure, the present invention employs a heat transfer tube support structure as described below.

6 is a perspective view of the heat transfer tube support structure according to the embodiment of the present invention, FIG. 7 is a front view of the heat transfer tube support structure, FIG. 8 is a plan view of the heat transfer tube support structure, and FIG. 9 is the heat transfer tube support structure. 1 is an explanatory diagram of a main part of FIG. 6 and 7, the finned heat transfer tube 31 is schematically shown with the fins 32 omitted.

As shown in FIGS. 6 to 9, among the finned heat transfer tubes 31 arranged in three staggered rows, the finned heat transfer tube arranged on the front side facing the inlet of the duct 12 (the most upstream side of the gas flow) Cylindrical protective members 36 are attached to 31 at two upper and lower positions with a support member 35 interposed therebetween. The protective member 36 is formed by arranging a plurality of split pieces around the fins 32 and welding them into a cylindrical shape. The mounting piece 37 forms a pair of upper and lower parts. By attaching such a protective member 36 to the existing heat transfer tube panel 30, even if the fins 32 are lost due to the vibration of the honeycomb support 33, the heat transfer tubes 31 are protected from coming into contact with the honeycomb support 33. .

A first reinforcing plate 38 is inserted obliquely to the left into the gaps between the finned heat transfer tubes 31 arranged in a staggered manner, and a second reinforcing plate 39 is inserted obliquely to the right so as to cross the first reinforcing plate 38 . inserted in the direction A first reinforcing plate 38 is supported on the honeycomb support 33 and a second reinforcing plate 39 is supported on the first reinforcing plate 38 in a crossed manner.

As shown in FIG. 9, the first reinforcing plate 38 is formed in a T shape having a pair of cutouts 38a. Since the first reinforcing plate 38 is placed on the honeycomb support 33, the first reinforcing plate 38 can be stably supported on the honeycomb support 33. The first reinforcing plate 38 may have a shape having only one notch 38a. Even when the protective member 36 is inserted from the front, the protective member 36 can always be accommodated in one of the cutouts 38a, so that the assembling workability can be improved.

The second reinforcing plate 39 is formed in an I-shape with a uniform width, and the length of the second reinforcing plate 39 is substantially the same as that of the first reinforcing plate 38 . In the case of this embodiment, since the first reinforcing plate 38 and the second reinforcing plate 39 are inserted in all the gaps of the finned heat transfer tubes 31 arranged in three rows in a staggered manner, one first reinforcing plate 38 and the second reinforcing plate 39 are inserted in a crossed state. The reinforcing plate 38 crosses three second reinforcing plates 39 and one second reinforcing plate 39 crosses three first reinforcing plates 38 .

One end sides of the first reinforcing plate 38 and the second reinforcing plate 39 protrude outward from the horizontal support 34 in a crossed state, and a flat plate is provided between the first reinforcing plate 38 and the second reinforcing plate 39 . shaped connecting member 40 is inserted. The first reinforcing plate 38 and the second reinforcing plate 39 are welded to both sides of the connecting member 40, and the connecting member 40 is welded to the horizontal support 34 so that the adjacent first reinforcing plate 38 and the second reinforcing plate 39 are fixed to the support member 35 (horizontal support 34) through a common connecting member 40. As shown in FIG.

As described above, in the heat transfer tube support structure according to the present embodiment, the structure in which the first reinforcing plate 38, the second reinforcing plate 39, and the connecting member 40 are joined in a triangular shape extends over the entire range of the support member 35. Therefore, all the finned heat transfer tubes 31 in each row can be made rigid, and even if the heat transfer tube panel 30 vibrates violently in the front-back direction and the left-right direction, the support member 35 and the fins 32 are damaged. can be suppressed. It should be noted that such a heat transfer tube support structure is preferably applied to all the support members 35 provided in a plurality of stages in the vertical direction of the heat transfer tube panel 30. The support members 35 on both ends may be omitted. Moreover, it is possible to omit the protective member 36, in which case both the first reinforcing plate 38 and the second reinforcing plate 39 may be I-shaped.

Next, the procedure for assembling the heat transfer tube support structure configured as described above will be described with reference to FIG.

In the existing heat transfer tube panel 30 arranged in the duct 12, the finned heat transfer tubes 31 staggered in three rows are bundled in the horizontal direction by a support member 35 consisting of a honeycomb support 33 and a horizontal support 34, A plurality of such support members 35 are provided in the vertical direction of the heat transfer tube panel 30 .

In the heat transfer tube support method according to the present embodiment, as shown in FIG. 10( a ), first, the first row of finned heat transfer tubes 31 arranged on the front side of the heat transfer tube panel 30 (the most upstream side of the gas flow) On the other hand, after the protective members 36 are attached to the two upper and lower positions with the support member 35 interposed therebetween, the portions where the protective members 36 are in contact with the honeycomb support 33 are welded to form a pair of upper and lower mounting pieces 37 .

Next, as shown in FIG. 10(b), the first reinforcing plate 38 is inserted into the gaps between the finned heat transfer tubes 31 from the front side of the heat transfer tube panel 30, and the first reinforcing plate 38 is arranged in a zigzag manner. It is arranged obliquely to the left in the gap between the finned heat transfer tubes 31 . Since a pair of notches 38a are formed in the first reinforcing plate 38, the first reinforcing plate 38 can be stably placed on the honeycomb support 33 by accommodating the protective member 36 in one of the notches 38a. can be placed. In addition, since the insertion amount of the first reinforcing plate 38 is defined by the notch 38a and the protective member 36, one end side of the first reinforcing plate 38 can be protruded from the outside of the horizontal support 34 by a predetermined amount. .

Next, as shown in FIG. 10(c), a second reinforcing plate 39 is inserted into the gap between the finned heat transfer tubes 31 so as to cross the first reinforcing plate 38, and this second reinforcing plate 39 is It is laid on the first reinforcing plate 38 and arranged obliquely to the right in the gap between the finned heat transfer tubes 31 . At that time, one end side of the second reinforcing plate 39 is projected outward of the horizontal support 34 by the same amount as the first reinforcing plate 38 .

Next, the connecting member 40 is fitted between the first reinforcing plate 38 and the second reinforcing plate 39 projecting from the horizontal support 34, and the first reinforcing plate 38 and the second reinforcing plate 39 are attached to the connecting member 40. By welding and joining the connecting member 40 to the horizontal support 34, one end sides of the first reinforcing plate 38 and the second reinforcing plate 39 are supported via the connecting member 40 as shown in FIG. It is fixed to member 35 .

As described above, according to the heat transfer tube support method according to the present embodiment, the existing heat transfer tube panels 30 bundled in the horizontal direction by the support members 35 are installed with the fins from the panel front side where the work space is secured. A structure in which the first reinforcing plate 38 and the second reinforcing plate 39 are inserted into the gap between the attached heat transfer tubes 31 to connect the first reinforcing plate 38, the second reinforcing plate 39 and the connecting member 40 in a triangular shape. can be easily formed over the entire range of the support member 35 . As a result, all the finned heat transfer tubes 31 in each row can be made rigid, so even if the heat transfer tube panel 30 vibrates violently in the front-back direction and in the left-right direction, damage to the support member 35 and damage to the fins 32 can be suppressed. can do.

In the above embodiment, the heat transfer tube panel 30 in which the heat transfer tubes 31 with fins are staggered in three rows has been described, but the heat transfer tubes 31 with fins may be staggered in two rows or four or more rows. In addition, the shape and fixing method of the first reinforcing plate 38 and the second reinforcing plate 39 are not limited to the above-described embodiment, and may be appropriately adjusted according to the staggered arrangement of the finned heat transfer tubes 31, the presence or absence of the protective member 36, and the like. It is possible to change.

FIG. 11 is a perspective view of a heat transfer tube support structure according to another embodiment of the present invention. An application example is shown.

As shown in FIG. 11, a first reinforcing plate 41 having a curved front side is obliquely inserted into a gap below the honeycomb support 33 of the heat transfer tubes 31 with fins arranged in two staggered rows. The front side of the first reinforcing plate 41 is fixed to the honeycomb support 33 via a connecting member 42 . In addition, a second reinforcing plate 43 having a curved back side is inserted obliquely into the gap above the honeycomb support 33 in the finned heat transfer tube 31 so as to intersect with the first reinforcing plate 41 . , the front side of the second reinforcing plate 43 is fixed to the honeycomb support 33 via another connecting member 44 .

FIG. 12 is a perspective view of a heat transfer tube support structure according to still another embodiment of the present invention. shows an example of the application of

As shown in FIG. 12 , the finned heat transfer tubes 31 arranged in two rows in a staggered manner are fitted with a cylindrical protective member 36 , which is welded to the honeycomb support 33 . A first reinforcing plate 41 having a curved front side is inserted obliquely into the gap below the honeycomb support 33 in the heat transfer tube 31 with fins. is fixed to the outer peripheral surface of the protection member 36 via the connecting member 42 . In addition, a second reinforcing plate 43 having a curved back side is inserted obliquely into the gap above the honeycomb support 33 in the finned heat transfer tube 31 so as to intersect with the first reinforcing plate 41 . , the front side of the second reinforcing plate 43 is fixed to the outer peripheral surface of the protective member 36 via another connecting member 44 .

In addition, the present invention is not limited to each embodiment described above, and includes various modifications. For example, each of the above-described embodiments has been described in detail in order to explain the present invention in an easy-to-understand manner, and is not necessarily limited to those having all the described configurations.

REFERENCE SIGNS LIST 1 gas turbine 2 heat recovery boiler 11 exhaust gas 12 duct 27 header 30 heat transfer tube panel 31 heat transfer tube (finned heat transfer tube)
32 Fin 33 Honeycomb support (support member)
34 horizontal support (support member)
35 Support member 36 Protection member 37 Mounting piece 38, 41 First reinforcing plate 38a Notch 39, 43 Second reinforcing plate 40, 42, 44 Connecting member

Claims (4)

A heat transfer tube panel in which a plurality of heat transfer tubes extending in the vertical direction are arranged in a zigzag pattern, and a support member for bundling the heat transfer tubes in the horizontal direction, wherein the support members are spaced apart in the vertical direction of the heat transfer tube panel. In the heat transfer tube support structure provided in a plurality of stages, a first reinforcing plate arranged in a diagonal direction in a gap between the plurality of heat transfer tubes, and a diagonal direction in the gap so as to intersect the first reinforcing plate and a connecting member that fixes one end side of each of the first reinforcing plate and the second reinforcing plate to the support member, and the heat transfer tube is provided with fins on the outer peripheral portion A cylindrical protective member surrounding the finned heat transfer tube is provided, the protective member is fixed to the support member , and the protective member sandwiches the support member 1. A heat transfer tube support structure, characterized in that it is divided into upper and lower parts and has a pair of upper and lower structure with attachment pieces . 2. The heat transfer tube support structure according to claim 1 , wherein the first reinforcing plate and the second reinforcing plate are fixed to the support member via the common connecting member. structure. 2. The heat transfer tube support structure according to claim 1 , wherein one of the first reinforcing plate and the second reinforcing plate is formed with a notch for avoiding contact with the protective member. A heat transfer tube support structure. A heat transfer tube panel in which a plurality of vertically extending heat transfer tubes are arranged in a zigzag pattern is arranged in a duct into which exhaust gas from a gas turbine flows, and the heat transfer tubes are horizontally bundled with support members. In addition, a heat transfer tube supporting method for a heat recovery boiler in which the support members are provided in a plurality of stages at predetermined intervals in the vertical direction of the heat transfer tube panels, wherein the gaps between the plurality of heat transfer tubes obliquely inserting a first reinforcing plate into the gap; obliquely inserting a second reinforcing plate into the gap so as to intersect with the first reinforcing plate; a step of fixing one end side of each of the second reinforcing plates to the support member via a connecting member;
including
The heat transfer tube is a finned heat transfer tube with fins attached to the outer peripheral portion, and is provided with a cylindrical protective member surrounding the finned heat transfer tube, the protective member is fixed to the support member ,
The heat transfer tube support method , wherein the protective member is provided by being divided into upper and lower parts with the support member interposed therebetween, and is formed into a pair of upper and lower structures by a mounting piece.

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