JP2014129971A - Heat transfer pipe assembly and heat recovery device having the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heat transfer pipe assembly that prevents self excited vibration of a heat transfer pipe and a heat recovery device having the same by determining progress of abrasion in fins of the heat transfer pipes so that the heat transfer pipes are stably supported.SOLUTION: There are formed a plurality of heat transfer pipes 4 arranged substantially parallel with each other with a predetermined interval, each of which extend in the substantially vertical direction and inside which heat medium flows, a plurality of fins disposed on the outer circumferential part of each heat transfer pipe 4, and penetration parts 6 through which the heat transfer pipes 4 having the fins are inserted. Also, a plurality of perforated plates 1 are arranged in a substantially horizontal direction and one of the plurality of heat transfer pipes 4 is a dummy tube 4a that has a friction part composed of a material which is abraded more easily than the fins.

Description

  The present invention relates to a heat transfer tube assembly suitable for use in, for example, an exhaust heat recovery device of an exhaust gas boiler, and a heat recovery device including the heat transfer tube assembly.

  Conventionally, a combined plant combining a prime mover and an exhaust heat recovery boiler is known for the purpose of heat recovery of high-temperature exhaust gas discharged from a prime mover such as a gas turbine or a diesel engine. Among this type of complex plant, a large number of recently planned and built are exhaust heat recovery combined cycle plants that combine a gas turbine using LNG as a fuel, an exhaust heat recovery boiler, and a steam turbine. . In such a complex plant, high-temperature exhaust gas discharged from a gas turbine or the like is guided to a heat recovery steam generator (HRSG).

  In recent years, an increase in the amount of exhaust gas accompanying an increase in the efficiency of a gas turbine in a combined cycle plant and an increase in exhaust gas temperature require an increase in capacity of the exhaust heat recovery boiler. As the gas turbine becomes larger, the HRSG also becomes larger, so that the conventional vertical HRSG has a limit in the height direction, so the horizontal HRSG has become mainstream.

  The horizontal type HRSG is a suspension type in which the heat transfer tube is suspended from above the duct through which the exhaust gas flows in the horizontal direction. Therefore, the heat transfer tube may vibrate when it receives a gas flow rate faster than a predetermined value. there were. As a document disclosing such a measure, there is the following Patent Document 1.

  In Patent Document 1, a tubular support member in a flat state is inserted into a mutual gap between heat transfer tubes arranged at intervals inside a heat exchanger shell, and the support member is expanded to expand the support member. A support structure for a heat exchanger heat transfer tube is shown in which the surface is pressed against the heat transfer tube to restrain the vibration of the heat transfer tube.

Japanese Utility Model Publication No. 5-96778

  However, in the heat exchanger heat transfer tube support structure disclosed in Patent Document 1, vibration is suppressed by attaching an elastic body between the support structure and the plurality of heat transfer tubes, so that the structure becomes complicated. There was a problem.

  In addition, in the vertical HRSG, the heat transfer tube is inserted laterally like a cantilever from the side wall, so that it can be held in contact with the support point by utilizing the deformation of the heat transfer tube due to its own weight. It was. However, in the horizontal type HRSG, the heat transfer tube is suspended from the upper side to the lower side, and therefore, it cannot be used so that the deformation due to the weight of the heat transfer tube is brought into contact with the support point. For this reason, the horizontal HRSG has a problem that the contact between the heat transfer tube and the porous plate supporting the heat transfer tube becomes unstable.

  As shown in FIG. 5, when the heat transfer tube 101 is not supported by the porous plate 104, a gap 105 is formed between the heat transfer tube 101 and the through portion 103 provided in the porous plate 104 through which the heat transfer tube 101 is inserted. The When this gap 105 is formed, there is a problem that the heat transfer tube 101 vibrates (self-excited vibration) due to poor contact with the porous plate 104. Further, there is a problem that the fin 102 provided on the heat transfer tube 101 is worn like the wear portion 102a by contacting with the through-hole 103 of the perforated plate 104 through which the heat transfer tube 101 is inserted during vibration.

  Further, since the number of contact points between the fins 102 and the perforated plate 104 provided in the heat transfer tube 101 is tens of thousands, it is difficult to inspect the progress of wear of all the fins 102 because it takes time and labor. There was a problem that there was.

  In order to prevent the self-excited vibration of the heat transfer tube, it is necessary to provide support points that support the heat transfer tube at a predetermined interval, but in order to function as a support point, the fin and the porous plate are loaded with a load higher than a predetermined value. There was the problem of having to keep in touch.

  When the perforated plate does not function as a support point for the heat transfer tube, the natural vibration of the heat transfer tube may change. Moreover, since the frequency changes when calculating the natural frequency of the heat transfer tube, the period of vibration changes. As a result, the natural frequency becomes small, and there is a problem that self-excited vibration of the heat transfer tube is likely to occur even at a low flow rate of the exhaust gas.

  This invention is made in view of such a situation, Comprising: By grasping | ascertaining progress of the wear of the fin of a heat exchanger tube, a heat exchanger tube is supported stably and the self-excited vibration of a heat exchanger tube is prevented. An object of the present invention is to provide a heat transfer tube assembly and a heat recovery apparatus including the heat transfer tube assembly.

In order to solve the above problems, the heat transfer tube assembly of the present invention and the heat recovery apparatus including the heat transfer tube assembly employ the following means.
The heat transfer tube assembly of the present invention is arranged substantially in parallel with a predetermined interval, each extending in a substantially vertical direction, and a plurality of heat transfer tubes through which a heat medium flows, and each of the heat transfer tubes A plurality of fins provided on the outer periphery, and a plurality of through-holes through which the heat transfer tubes including the fins are inserted, and a plurality of perforated plates arranged in a substantially horizontal direction. Any one of the heat tubes is a dummy tube having a wear part made of a material that is more easily worn than the fins.

  A plurality of heat transfer tubes are provided that are arranged substantially in parallel with a predetermined interval, each extending in a substantially vertical direction, and in which a heat medium (for example, steam) flows. A plurality of fins for supporting the heat transfer tubes are provided on the outer periphery of each heat transfer tube. Exhaust gas discharged from a boiler or the like comes into contact with each heat transfer tube. Any one of the plurality of heat transfer tubes is provided with a dummy tube having a wear portion made of a material that is more easily worn than fins provided on the heat transfer tubes.

  Thereby, the wear state of other fins can be estimated only by examining the wear of the dummy tube. Therefore, it is not necessary to inspect the wear of the fins provided in all the heat transfer tubes, and only the dummy tube needs to be measured, so that the labor of the inspection work can be reduced. The amount of wear of the dummy tube is, for example, twice that of the fin. When the wear of the dummy tube is 3 mm, it can be estimated that the fin is worn by 6 mm. Further, since the wear state of the fins provided in the plurality of heat transfer tubes can be grasped from the wear value of the dummy tube, it is possible to know the timing of the total inspection of the fins. In addition, by preventing wear of the fins, it is possible to prevent the formation of a gap with the penetrating portion provided in the porous plate, so that the fins of the heat transfer tubes can be reliably supported by the porous plate. Therefore, generation | occurrence | production of the self-excited vibration of a heat exchanger tube can be prevented.

  Furthermore, in the heat transfer tube assembly according to the present invention, the dummy tube is disposed at the fluid flow direction position equivalent to the heat transfer tube located upstream of the fluid flow to exchange heat with the heat medium, or further upstream. It is characterized by being.

  The dummy tube is provided upstream of the position where the fluid (for example, exhaust gas) and the plurality of heat transfer tubes contact. By providing the dummy tube upstream of the contact position between the fluid and the heat transfer tube where the heat transfer tube is most likely to wear, the wear of the plurality of heat transfer tubes positioned downstream of the dummy tube can be grasped. Note that the dummy tube is a test piece that is used only to know the amount of wear of the dummy tube without flowing steam inside.

  A heat recovery apparatus according to the present invention includes the above heat transfer tube assembly.

  By providing the heat transfer tube assembly in a heat recovery device (for example, an exhaust heat recovery device (HRSG) that recovers exhaust heat of the gas turbine and generates steam), poor contact between the heat transfer tube and the porous plate can be prevented. . Therefore, it can be set as the heat recovery apparatus which can prevent the self-excited vibration of a heat exchanger tube.

  Any one of the plurality of heat transfer tubes is provided with a dummy tube having a wear portion made of a material that is more easily worn than fins provided on the heat transfer tubes. Thereby, the wear state of other fins can be estimated only by examining the wear of the dummy tube. Therefore, it is not necessary to inspect the wear of the fins provided in all the heat transfer tubes, and only the dummy tube needs to be measured, so that the labor of the inspection work can be reduced. By preventing the wear of the fins of the heat transfer tube from proceeding, the fins of the heat transfer tube and the penetrating portion provided in the porous plate can be brought into contact with each other. Therefore, generation | occurrence | production of the self-excited vibration of a heat exchanger tube can be prevented.

It is the side view which showed the heat recovery apparatus with which the heat exchanger tube assembly of this invention is applied. It is the partial detail figure which showed the heat exchanger tube assembly of this invention. It is the cross-sectional view which showed 1st Embodiment of the heat exchanger tube assembly of this invention. It is the cross-sectional detail drawing which showed 2nd Embodiment of the heat exchanger tube assembly of this invention. It is the partial detail figure which showed the reference example of the heat exchanger tube assembly of this invention.

Hereinafter, an embodiment of a heat transfer tube assembly and a heat recovery apparatus including the heat transfer tube assembly according to the present invention will be described with reference to the drawings.
The heat recovery apparatus 10 (see FIG. 1) of the present invention is applied to a horizontal HRSG (hereinafter simply referred to as “HRSG”) (not shown). In the HRSG, exhaust gas discharged from a gas turbine (not shown) flows horizontally in a duct (not shown), and steam is generated by the heat transfer tubes 4 (see FIG. 1) arranged vertically. The HRSG that constitutes the combined cycle power plant (not shown) is a facility that generates steam using the exhaust heat of the gas turbine and supplies the steam to the steam turbine (not shown).

  The HRSG is arranged as a group in which a plurality of heat transfer tubes 4 (see FIG. 1) are bundled with a metal band or the like inside a casing (not shown) supported by a steel structure support. Steam or hot water is conducted between a group of heat transfer tubes 4 between a steam drum or a steam turbine (not shown) via a header 5 (see FIG. 1). A plurality of heat transfer tubes 4 are suspended in the casing.

[First Embodiment]
As shown in FIG. 1, the plurality of heat transfer tubes 4 extend in a substantially vertical direction in a casing (not shown), and are arranged substantially in parallel with a predetermined interval. A heat medium (for example, steam) is circulated inside the heat transfer tube 4, and a plurality of fins 3 (see FIG. 2) are joined to the outer peripheral portion of the heat transfer tube 4 by welding.

  Similarly, a plurality of perforated plates 1 are provided in the casing. As shown in FIG. 2, the perforated plate 1 (not shown) has a through portion 6 through which the heat transfer tube 4 including the fins 3 is inserted. The fins 3 provided on the outer peripheral portion of the heat transfer tube 4 are for promoting heat transfer of the heat transfer tube 4. Further, the heat transfer tubes 4 are supported by the fins 3 coming into contact with the through portions 6 of the perforated plate 1.

  As shown in FIG. 3, any one of the plurality of heat transfer tubes 4 is a dummy tube 4 a having a wear portion made of a material that is more easily worn than the fins 3. In other words, a dummy tube 4 a that is more easily worn than the fins 3 whose wear conditions are known is provided in the tube group of the heat transfer tubes 4. Note that the dummy tube 4a is a test piece only for knowing the amount of wear of the dummy tube 4a without flowing steam inside the tube. The number of dummy tubes 4a is, for example, one for the heat transfer tube 4 group.

  For example, 1Cr steel is used as the material of the fin 3. Moreover, carbon steel softer than 1Cr steel is used for the material of the dummy pipe | tube 4a, for example. Further, the porous plate 1 is made of the same material as the fin 3, and the fin 3 side having a small contact area with the porous plate 1 is worn.

The wear conditions of the fins 3 are specific wear amounts [mm / (N / mm ² · m / s · hr)], load surface pressure [N / mm ² ] and wear sliding speed [mm / s]. The estimated wear amount is derived from the following equation.
W = K × P × V × T
W is the estimated wear size (mm), K is the specific wear amount [mm / (N / mm ² · m / s · hr)], P is the load surface pressure (N / mm ² ), V is the wear sliding speed ( mm / s), T represents sliding time (hr).

Next, the operation of the heat transfer tube assembly configured as described above will be described.
Exhaust gas discharged from a gas turbine (not shown) contacts the group of heat transfer tubes 4 shown in FIG. The heat transfer tube 4 generates steam by utilizing exhaust heat from the exhaust gas. The upstream side of the heat transfer tube 4 in contact with the exhaust gas makes contact with the exhaust gas at a high flow rate, and therefore the upstream side of the heat transfer tube 4 in the group has a greater resistance to the exhaust gas. In addition, by installing a dummy tube 4a adjusted in material so as to be more easily worn than the fins 3 of the plurality of heat transfer tubes 4 at locations where the exhaust gas flow rate is high and in contact with the heat transfer tubes 4, the heat transfer tubes 4 First, the dummy tube 4a is worn quickly.

According to this embodiment, there exist the following effects.
Any one of the plurality of heat transfer tubes 4 is provided with a dummy tube 4 a having a wear portion made of a material that is more easily worn than the fins 3 provided on the heat transfer tube 4. Thereby, the wear state of the other fin 3 can be estimated only by examining the wear of the dummy tube 4a.

  Further, it is not necessary to inspect the wear of the fins 3 provided in all the heat transfer tubes 4, and only the dummy tube 4a needs to be measured, so that the labor of the inspection work can be reduced. The amount of wear of the dummy tube 4a is, for example, twice that of the fin 3, and when the wear of the dummy tube 4a is 3 mm, it can be estimated that the fin 3 is worn by 6 mm.

  Furthermore, since the wear state of the fins 3 provided in the plurality of heat transfer tubes 4 can be grasped from the wear value of the dummy tube 4a, the time for the total inspection of the fins 3 can be known. Moreover, by preventing wear of the fins 3, it is possible to prevent a gap from being formed with the through portion 6 provided in the porous plate 1. Thereby, the fin 3 of the heat exchanger tube 4 can be reliably supported by the porous plate 1. Therefore, generation | occurrence | production of the self-excited vibration of the heat exchanger tube 4 can be prevented.

  Since the dummy tube 4a is a test piece that does not flow steam, there is no problem in operation of the heat recovery apparatus 10 even if it is worn. Thereby, even if the dummy tube 4a is damaged, the heat recovery apparatus 10 is not stopped, so that the heat recovery apparatus 10 can be operated stably.

[Second Embodiment]
Next, a second embodiment of the present invention will be described with reference to FIG.
In the present embodiment, the dummy tube 4a shown in the first embodiment is arranged at the fluid flow direction position equivalent to the heat transfer tube 4 located on the upstream side of the fluid flow to exchange heat with the heat medium, or further on the upstream side. It is a thing. Therefore, the same components as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted.
As shown in FIG. 4, the dummy tube 4a is located at the fluid flow direction (direction of arrow a) equivalent to the heat transfer tube 4 located on the upstream side of the fluid flow that exchanges heat with the heat medium, or further upstream. Arranged on the side. The dummy tube 4a is supported by a through portion 6a provided in the porous hole 1a. Moreover, it is provided in the upstream rather than the position where fluid (for example, exhaust gas) and the some heat exchanger tube 4 contact. Since the exhaust gas discharged from the gas turbine flows in the direction of arrow a and the exhaust gas and the heat transfer tube 4 have the largest contact, the dummy tube 4a is worn in an environment where it is most likely to be worn. The installation location of the dummy tube 4a is, for example, the center side of the heat recovery apparatus 10 (see FIG. 1) through which a high exhaust gas flow rate flows.

  According to the present embodiment, by providing the dummy tube 4a on the upstream side of the contact position between the exhaust gas and the heat transfer tube 4 where wear of the heat transfer tube 4 is most likely to occur, a plurality of positions located on the downstream side of the dummy tube 4a are provided. The wear of the heat transfer tube 4 can be grasped. Further, the wear state of the dummy tube 4a can be detected earliest. Thereby, the wear condition of the heat exchanger tube 4 can be quickly grasped from the wear condition of the dummy tube 4a.

1 perforated plate 1a perforated plate 3 fin 4 heat transfer tube 4a dummy tube 5 header 6 penetrating portion 6a penetrating portion 10 heat recovery device

Claims (3)

A plurality of heat transfer tubes that are arranged substantially in parallel with a predetermined interval, each extending in a substantially vertical direction, and in which a heat medium flows, and
A plurality of fins provided on the outer periphery of each of the heat transfer tubes;
A through-hole through which the heat transfer tube including the fin is inserted is formed, and a plurality of perforated plates arranged in a substantially horizontal direction, and
Any one of the plurality of heat transfer tubes is a dummy tube having a wear portion made of a material that is more easily worn than the fins.   The dummy tube is arranged at a fluid flow direction position equivalent to the heat transfer tube located upstream of a fluid flow to exchange heat with the heat medium, or further upstream. The heat transfer tube assembly as described.   A heat recovery apparatus comprising the heat transfer tube assembly according to claim 1.

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