JP2006029652A - Vibration prevention structure of bank of heat transfer tubes and boiler equipped with vibration prevention structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vibration prevention structure of a bank of heat transfer tubes capable of preventing increase of facility cost by preventing vibration of the heat transfer tubes securely for a long time by a simple method and having excellent efficiency of heat transfer and to provide a boiler provided with the vibration prevention structure of the bank of the heat transfer tubes. <P>SOLUTION: In this vibration prevention structure of a plurality of banks 1 of the heat transfer tubes provided in the vertical direction in the boiler, adjacent heat transfer tubes 10 are mutually joined in at least one section or more except a top end part and a bottom end part. In a heat transfer tube 10a to which other heat transfer tubes are adjacent on both sides, a join part of the heat transfer tube 10a with a heat transfer tube 10b adjacent to it on one side and a join part with a heat transfer tube 10c on the other side are provided at positions where directions of height of the heat transfer tubes are different. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a vibration preventing structure for a heat transfer tube array in a boiler and a boiler having the vibration preventing structure for the heat transfer tube array.

  Waste treatment furnaces that treat municipal waste, sewage sludge, human waste sludge, flammable industrial waste, etc. (hereinafter simply referred to as “waste”) include gases discharged from the waste treatment furnace, such as incinerators. In general, a waste heat recovery boiler is provided in order to recover and effectively use waste heat in exhaust gas such as combustion exhaust gas discharged or product gas discharged from a gasification melting furnace. In such a waste heat recovery boiler, a heat transfer tube array is provided in the exhaust gas flow path, where waste heat recovery of the exhaust gas is performed, and power is generated by driving a steam turbine with the generated steam. .

  If fly ash in the exhaust gas adheres to the surface of the heat transfer tube in the waste heat recovery boiler (hereinafter referred to as “adhesion ash”), the efficiency of heat recovery is impaired. Ashes are removed. One method for removing the adhering ash is a method for removing adhering dust using a hammering device. The method for removing adhering dust using a hammering device is to apply an impact to the heat transfer tube array from the outside of the boiler with a rotary hammer or the like, and to remove the dust adhering to the surface of the heat transfer tube by the impact.

  Adhesive ash removal by the hammering device has a dust removal effect when the heat transfer tube row is arranged in the vertical direction and is suspended. Therefore, waste heat recovery boilers, for example, tail end type boilers, are often used that have a structure in which heat transfer tubes are arranged in the vertical direction. In addition, the attachment pipe which comprises a header is welded to the upper end part and lower end part of the said heat exchanger tube.

  However, in a waste heat recovery boiler having a structure in which a large number of heat transfer tube rows are provided in the vertical direction, the heat transfer tubes provided in the vertical direction are suspended without support in consideration of the effect of dust removal. However, in such a structure, the heat transfer tubes may vibrate due to the exhaust gas flowing between the heat transfer tube rows, and the boiler may generate noise or adversely affect other equipment.

  This is particularly a problem in large tail end boilers. In a large tail end type boiler, the length of the heat transfer tube provided in the vertical direction becomes long, so that its natural frequency decreases in inverse proportion to the square of the length. When the exhaust gas flows between the heat transfer tubes provided in the vertical direction and performs heat exchange, the gas generates vortices (Karman vortices) and turbulence, which vibrates the subsequent heat transfer tubes. When the generation frequency of the Karman vortex or the like is close to the natural frequency of the heat transfer tube, vibration of the tube occurs due to resonance.

  In conventional tail-end boilers, vibration prevention of the heat transfer tube rows has been performed by preventing the flow velocity of the passing gas from increasing above the limit value. In other words, the gas flow velocity is determined by selecting the pipe diameter and length so that the natural frequency of the heat transfer pipe is higher than the Karman vortex generation frequency even at the maximum gas volume at the boiler capacity at the time of planning. . However, since the natural frequency decreases as the capacity of the boiler increases and the length of the heat transfer tube increases, the gas flow rate must be kept low, and therefore the size of the tail end must be increased. It was a situation that I did not get.

  From the viewpoint of preventing vibration of the heat transfer tube array, for example, Japanese Patent Application Laid-Open No. 11-237001 (Patent Document 1) and Japanese Patent Application Laid-Open No. 2000-18501 (Patent Document 2) are provided for preventing vibration of the heat transfer tube. A heat transfer tube structure is disclosed.

In Patent Document 1, a plurality of heat transfer tubes are attached in the tube axis direction of the heat transfer tube, and at least one of the heat transfer tubes has a vibration isolation support that is divided and attached in a direction perpendicular to the tube axis. A thermal tube structure is disclosed. Further, Patent Document 2 relates to a heat transfer tube of an exhaust heat recovery boiler in which a large number of heat transfer tubes are arranged, and covers both sides of the casing width direction perpendicular to the exhaust gas flow direction with vibration isolation plates, A tube bundle support member for connecting the heat transfer tubes in the horizontal direction at a required position in the vertical direction of the heat transfer tubes of the respective blocks is connected to each other by a connecting member disposed at a predetermined interval in the vertical direction. An arranged heat transfer tube structure is disclosed.
JP-A-11-237001 JP 2000-18501 A

  However, the method described in Patent Document 1 has a problem that vibration cannot be suppressed when the vibration modes of the heat transfer tubes are aligned in parallel tubes. Moreover, although the method of the said patent document 1 and the patent document 2 uses the anti-vibration support, the anti-vibration board, the connection member, etc. in order to bundle a heat exchanger tube, the gas which flows between heat exchanger tubes is waste combustion. In the case of exhaust gas, the corrosion components in the exhaust gas and the temperature rise due to heating by the exhaust gas, the anti-vibration support, anti-vibration plates, connecting members, etc. can be corroded in a short period of time or damaged and prevented from vibration. There is a problem that it can not be done.

  The present invention has been made to solve the above-mentioned problems, and it is possible to prevent an increase in equipment cost and excellent heat transfer efficiency by reliably preventing vibration of the heat transfer tube over a long period of time by a simple method. It aims at providing the vibration prevention structure of a heat exchanger tube row | line | column, and the boiler provided with the vibration prevention structure of this heat exchanger tube row | line | column.

The above problems are solved by the following invention.
[1] A vibration preventing structure for a plurality of heat transfer tube rows provided in a vertical direction in a boiler,
Adjacent heat transfer tubes are joined at at least one location other than the upper end and the lower end,
In a heat transfer tube in which other heat transfer tubes are adjacent to both sides, the junction between the heat transfer tube and one of the adjacent heat transfer tubes and the junction between the other heat transfer tube are different in the heat transfer tube height direction. A vibration preventing structure for a heat transfer tube array, characterized by being provided at a position.
[2] The vibration preventing structure of a heat transfer tube array according to [1], wherein adjacent heat transfer tubes are joined together through a member having corrosion resistance.
[3] The vibration preventing structure of a heat transfer tube array according to [1], wherein adjacent heat transfer tubes are joined to each other through a pipe through which a fluid can pass.
[4] In the above [1], a bent portion is provided in one or both of the adjacent heat transfer tubes, and the adjacent heat transfer tubes are joined directly or via a member having corrosion resistance at the bent portion. A vibration-preventing structure for heat transfer tube arrays.
[5] A vibration preventing structure of a plurality of heat transfer tube rows provided in the vertical direction in the boiler,
The vibration of the heat transfer tube row, characterized in that an intermediate mounting tube is provided at least at one location between the upper mounting tube provided at the upper end portion of the heat transfer tube row and the lower mounting tube provided at the lower end portion. Prevention structure.
[6] A boiler comprising the heat transfer tube row vibration preventing structure according to any one of [1] to [5].

  According to the present invention, it is possible to prevent vibration of the heat transfer tube reliably and simply over a long period of time by using a simple method, thereby preventing an increase in equipment cost and a heat transfer tube row vibration prevention structure excellent in heat transfer efficiency. A boiler having a structure for preventing vibration of a heat tube array is provided.

  Hereinafter, an example of the best mode for carrying out the present invention will be described.

  One embodiment of the vibration preventing structure of a heat transfer tube row according to the present invention relates to a plurality of heat transfer tube rows provided in a vertical direction in a boiler, and at least one place where adjacent heat transfer tubes are other than an upper end portion and a lower end portion. In the heat transfer tube which is joined as described above and has other heat transfer tubes adjacent to both sides, the joint between the heat transfer tube and one of the heat transfer tubes adjacent thereto and the joint between the other heat transfer tube are connected to the heat transfer tube. They are provided at different positions in the height direction.

  By adopting such a structure, it is possible to restrain the vibration of the heat transfer tube at the joint between adjacent heat transfer tubes and increase the natural frequency of the heat transfer tube array. Furthermore, regarding the heat transfer tube in which other heat transfer tubes are adjacent on both sides, the junction between the heat transfer tube and one of the heat transfer tubes adjacent to the heat transfer tube and the other heat transfer tube are connected to the heat transfer tube height. By providing at different positions, it is possible to make a difference in the natural frequency of each heat transfer tube constituting the heat transfer tube row, and it is possible to further enhance the vibration prevention effect of the heat transfer tube row.

  Hereinafter, a method of joining adjacent heat transfer tubes at at least one place other than the upper end and the lower end will be described.

  FIG. 1 is a schematic configuration diagram showing an example of a method of joining adjacent heat transfer tubes at at least one place other than the upper end and the lower end. Here, the adjacent heat transfer tubes are joined together via the member 5 having corrosion resistance.

  As the member 5 having corrosion resistance, a material having high corrosion resistance and high thermal conductivity is preferably used. As such a thing, it is preferable to use the same material as the material of the heat exchanger tube 10, for example, SUS310, Alloy625, Alloy825, etc. can be used.

  Corrosive components such as chlorides are contained in the exhaust gas discharged from the incinerator or the gasification and melting furnace for treating garbage. Therefore, like the heat transfer tube, the member 5 is required to have high corrosion resistance. However, even if the material has high corrosion resistance, the corrosion is accelerated when the temperature becomes high. That is, it is necessary to prevent the member 5 from having a high temperature at which corrosion is accelerated.

  Therefore, with respect to the member 5, by using a material having high thermal conductivity, a cooling effect from the heat transfer tube can be expected, and promotion of corrosion due to high temperature can be prevented. In addition, it is preferable to join the said member 5 by methods, such as welding, so that the contact area with the heat exchanger tube 10 may be enlarged so that the heat conduction to the heat exchanger tube 10 can be performed efficiently.

  In the example shown in FIG. 1, the heat transfer tubes adjacent to each other are joined so that the joining positions are on a substantially diagonal line of the heat transfer tube row. Thereby, regarding the heat transfer tube 10a in which the other heat transfer tubes are adjacent to each other, the joint portion between the heat transfer tube 10a, one heat transfer tube 10b adjacent to the heat transfer tube 10a, and the other heat transfer tube 10c. Thus, the heat transfer tube is provided at a different position in the height direction, and the natural frequency of the adjacent heat transfer tube can be made different, thereby improving the vibration preventing effect.

  Moreover, in FIG.2 and FIG.3, an example of the other pattern about the joining position of adjacent heat exchanger tubes is shown.

  In the example shown in FIG. 2, in addition to the joining position shown in FIG. 1, the adjacent heat transfer tubes are further joined at one place via the member 5 so as to be substantially parallel to the joining position. . As a result, the natural frequency of each heat transfer tube can be further increased, and the vibration preventing effect can be further improved.

  In the example shown in FIG. 3, in addition to the joining position shown in FIG. 1, the joining is performed via the member 5 so that the joining position is on the other substantially diagonal line. Thereby, like the case of FIG. 2, the natural frequency of each heat exchanger tube can be further raised, and the vibration preventing effect can be further improved.

  In addition, it cannot be overemphasized that it is not limited to said example regarding the joining position of adjacent heat exchanger tubes, It is adjacent to this heat exchanger tube and this regarding the heat exchanger tube which the other heat exchanger tube adjoins on both sides. The object of the present invention can be achieved by a method in which the joint between one heat transfer tube and the joint between the other heat transfer tube are provided at different positions in the heat transfer tube height direction.

  FIG. 4 shows another example of a method of joining adjacent heat transfer tubes at at least one place other than the upper end and the lower end. Here, adjacent heat transfer tubes are joined together via a pipe 6 through which fluid can pass.

  As the pipe 6, it is not always necessary to use the same material as that of the heat transfer tube 10 in consideration of corrosion resistance and the like, and for example, STB, STP, STPT, SUS material or the like can be used. Moreover, joining of the said piping 6 and the heat exchanger tube 10 can use methods, such as welding and fitting, for example.

  As the pipe 6, for example, an evaporation pipe, a superheater pipe, a economizer pipe, a reheater pipe, a pipe independent of a boiler, or the like can be used. Moreover, as a fluid which lets the inside of the said piping 6 pass, boiler water, boiler feed water, a vapor | steam, etc. can be used, for example. By allowing the fluid to pass through the inside of the pipe 6, it is possible to prevent high temperature corrosion of the joint portion between the pipe 6 and the heat transfer pipe due to the cooling effect of the pipe 6 by the fluid.

  Note that the joining of the pipe 6 and the heat transfer tube 10 is not limited to the example shown in FIG. 4 (examples indicated by solid lines and dotted lines), but relates to heat transfer tubes in which other heat transfer tubes are adjacent on both sides. The present invention achieves the object of the present invention as long as it is a method in which the joint between the heat transfer tube and one of the heat transfer tubes adjacent thereto and the joint between the other heat transfer tube are provided at different positions in the heat transfer tube height direction. it can.

  FIG. 5 shows another example of a method of joining adjacent heat transfer tubes at at least one place other than the upper end and the lower end. Here, a bent portion 7 is provided in one or both of the adjacent heat transfer tubes, and the adjacent heat transfer tubes are joined at the bent portion directly or via the member 5 having corrosion resistance.

  As the joining method, for example, methods such as welding and fitting can be used.

  By providing a bent portion 7 in the heat transfer tube, shortening the distance from the adjacent heat transfer tube, and joining the heat transfer tube to the adjacent heat transfer tube directly or via the member 5 having corrosion resistance, The cooling effect of the heat transfer tube on the joint is improved, and high temperature corrosion at the joint can be prevented.

  The joining position of the bent portion 7 and the heat transfer tube 10 is not limited to the example shown in FIG. 5, and can be provided at the same position as the member 5 of FIG. 2 or FIG. Further, regarding a heat transfer tube in which other heat transfer tubes are adjacent on both sides, a joint portion between the heat transfer tube and one heat transfer tube adjacent to the heat transfer tube is connected to a heat transfer tube height. The object of the present invention can be achieved as long as it is a method provided at different positions.

  FIG. 6 is a schematic configuration diagram showing another embodiment of the vibration preventing structure for a heat transfer tube array according to the present invention.

  The vibration prevention structure of the heat transfer tube row shown in FIG. 6 is at least one place between the upper attachment tube 2 provided at the upper end portion of the heat transfer tube row 1 and the lower attachment tube 3 provided at the lower end portion. An intermediate mounting tube 4 is provided. In the boiler, a plurality of heat transfer tube rows 1 provided in the vertical direction are provided in the gas flow direction, and heat exchange is performed there.

  The upper mounting tube 2, the lower mounting tube 3, and the intermediate mounting tube 4 constitute a header, and water and / or water vapor flowing in each heat transfer tube of the heat transfer tube row 1 is contained in each mounting tube. Will be joined.

  As shown in FIG. 6, by providing an intermediate mounting tube 4 between the upper mounting tube 2 and the lower mounting tube 3, the vibration of the heat transfer tube is restrained and the natural frequency of the heat transfer tube array 1 is increased. As a result, the vibration preventing effect of the heat transfer tube array 1 can be enhanced. Here, by adjusting the attachment position and the number of attachments of the intermediate attachment tube 4, the natural frequency of the heat transfer tube row 1 can be adjusted, and the size and operating conditions of the boiler to which the heat transfer tube row 1 is attached, etc. In consideration of the above, the attachment position and the number of attachments of the intermediate attachment pipe 4 are adjusted.

  The intermediate mounting tube 4 is overheated by the cooling effect of water and / or steam flowing in the intermediate mounting tube 4 by forming a header like the upper mounting tube 2 and the lower mounting tube 3. It is possible to prevent corrosion and promote corrosion.

  In the configuration shown in FIG. 6, a hammering device is attached to the intermediate mounting pipe 4 and the intermediate mounting pipe 4 is hit to effectively remove the attached ash adhering to the heat transfer pipe surface of the heat transfer pipe array 1. It can be removed.

  As described above, when the vibration prevention structure of the heat transfer tube array according to the present invention is adopted, the natural frequency of the heat transfer tube array 1 is increased, and the passage speed of the exhaust gas passing through the boiler section is increased. However, the vibration of the heat transfer tube can be suppressed. As a result, it is possible to increase the passage speed of the exhaust gas that passes through the boiler section, so that the heat transfer efficiency to the heat transfer tubes is increased and the size of the heat transfer tube row 1 can be reduced. Thereby, it becomes possible to reduce a boiler part and to prevent an increase in equipment cost.

  The boiler to which the vibration preventing structure of the heat transfer tube row according to the present invention described above is applied is not particularly limited. For example, waste such as municipal waste, sewage sludge, human waste sludge, and flammable industrial waste is treated. The present invention can be applied to a waste heat recovery boiler for recovering waste heat from exhaust gas such as combustion exhaust gas discharged from an incinerator or product gas discharged from a gasification melting furnace.

  The following table shows the results of measurement of the natural frequency of the heat transfer tube and the flow rate of the passing gas at which vibration occurs with respect to the heat transfer tube row to which the heat transfer tube row vibration preventing structure according to the present invention (Invention Examples 1 and 2) is applied. It is shown in 1.

  Here, Example 1 of the present invention is measured when bonded at the bonding position shown in FIG. 2 in the above-described embodiment, and Example 2 of the present invention is measured when bonded at the bonding position shown in FIG. 6 in the above-described embodiment. It was.

  Further, the length of the heat transfer tube was measured by using about 7 m of both the inventive examples 1 and 2 and the comparative example.

  As shown in Table 1 above, with respect to the heat transfer tube row to which the vibration prevention structure of the heat transfer tube row according to the present invention is applied, the joint portion other than the upper end portion and the lower end portion of the heat transfer tube row which is the prior art (comparative example) Compared to the case where there is no gas, the natural frequency is about twice, and the gas flow rate until the vibration occurs is about twice to three times or more, and the effect of the present invention can be confirmed.

It is a schematic block diagram which shows an example of the method which joins the adjacent heat exchanger tubes based on this invention in at least 1 place other than an upper end part and a lower end part, and adjoins through the member which has corrosion resistance It is the figure which showed the case where joining is performed. It is a figure which shows an example of the other pattern about the joining position of the adjacent heat exchanger tubes based on this invention. It is a figure which shows an example of the other pattern about the joining position of the adjacent heat exchanger tubes based on this invention. It is a schematic block diagram which shows an example of the method which joins the adjacent heat exchanger tubes based on this invention in at least 1 or more places other than an upper end part and a lower end part, and it adjoins through the piping which a fluid can pass inside. It is the figure which showed the case where a heat exchanger tube is joined. It is a schematic block diagram which shows an example of the method of joining the adjacent heat exchanger tubes based on this invention in at least 1 place other than an upper end part and a lower end part, and bend | folds to one or both part of an adjacent heat exchanger tube It is the figure which showed the case where a part was provided and the adjacent heat exchanger tube was joined in the said bending part directly or via the member which has corrosion resistance. It is a schematic block diagram which shows other embodiment of the vibration prevention structure of the heat exchanger tube line which concerns on this invention.

Explanation of symbols

1 Heat Transfer Tube Row 2 Upper Mounting Tube 3 Lower Mounting Tube 4 Intermediate Mounting Tube 5 Member 6 Piping 7 Bent 10 Heat Transfer Tube

Claims (6)

In the boiler, the vibration prevention structure of a plurality of heat transfer tube rows provided in the vertical direction,
Adjacent heat transfer tubes are joined at at least one location other than the upper end and the lower end,
In a heat transfer tube in which other heat transfer tubes are adjacent to both sides, the junction between the heat transfer tube and one of the adjacent heat transfer tubes and the junction between the other heat transfer tube are different in the heat transfer tube height direction. A vibration preventing structure for a heat transfer tube array, characterized by being provided at a position.   The heat transfer tube row vibration preventing structure according to claim 1, wherein adjacent heat transfer tubes are joined together through a member having corrosion resistance.   2. The vibration preventing structure for a heat transfer tube array according to claim 1, wherein adjacent heat transfer tubes are joined to each other through a pipe through which a fluid can pass.   The bent portion is provided in one or both of the adjacent heat transfer tubes, and the adjacent heat transfer tubes are joined at the bent portion directly or through a member having corrosion resistance. Anti-vibration structure for heat transfer tube rows. In the boiler, the vibration prevention structure of a plurality of heat transfer tube rows provided in the vertical direction,
The vibration of the heat transfer tube row, characterized in that an intermediate mounting tube is provided at least at one place between the upper mounting tube provided at the upper end portion of the heat transfer tube row and the lower mounting tube provided at the lower end portion. Prevention structure.   The boiler provided with the vibration prevention structure of the heat exchanger tube row in any one of Claims 1 thru | or 5.

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