JP2010255925A - Cleaning device for exhaust gas heat recovery device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cleaning device for an exhaust gas heat recovery device capable of cleaning dust adhered and deposited on a heat transfer tube surface of an interior of the exhaust gas heat recovery device without leaving any uncleaned portions. <P>SOLUTION: The cleaning device is a device cleaning outer surfaces of a plurality of vertically arranged heat transfer tubes 2 in the exhaust gas heat recovery device 200, it is equipped with a vibration preventing plate provided in a direction orthogonal to the heat transfer tubes and suppressing vibration of the heat transfer tubes, a cleaning water supply pipe, a flexible tube connected to the cleaning water supply pipe, arranged between the heat transfer tubes in an orthogonal direction to a length direction of the heat transfer tubes and in a parallel direction with an exhaust gas flow, and equipped with a plurality of cleaning water jet holes, and a support tube arranged along a length direction of the flexible tube, the flexible tube is heat resistant and corrosion resistant, and cleaning water is jetted obliquely upward toward the vibration preventing plate from the cleaning water jet holes. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an exhaust gas heat recovery device cleaning device.

  In recent years, there has been an urgent need to reduce carbon dioxide emissions to prevent global warming. In order to reduce carbon dioxide emissions, it is important to improve the use of thermal energy in combustion. In particular, if the thermal energy of the combustion exhaust gas is recovered and reused, the use combustion can be reduced, and the carbon dioxide emission can be reduced.

  In the heat recovery device, heat energy is recovered by passing fluids through the shell and the heat transfer tube and exchanging heat between them. In the heat recovery unit, the heat transfer area is secured by arranging the heat transfer tubes densely. For this reason, when the heat recovery device is applied to the exhaust gas, there is a problem that dust contained in the exhaust gas adheres to and accumulates on the surface of the heat transfer tube, and clogging occurs between the tube groups of the heat transfer tube. As dust adheres and accumulates, the amount of heat recovered decreases as the heat transfer performance decreases, and the pressure loss on the gas side increases, which may make it impossible to operate the heat recovery unit.

  Conventionally, cleaning water has been sprayed from a spray pipe installed on the upstream side of a tube group of heat transfer tubes in order to remove dust adhered to and accumulated on the heat transfer tubes. However, simply spraying the cleaning water from the outside of the heat transfer tube does not spread the cleaning water to the heat transfer tube inside the tube group, making it difficult to perform sufficient cleaning.

  As an apparatus for cleaning the heat exchanger, an apparatus for cleaning the inside of the heat exchanger by spraying a cleaning liquid from a nozzle head installed on a support plate that supports a heat transfer tube is known (for example, Patent Document 1). However, such an apparatus is applied for cleaning sludge inside an evaporator having a shell-and-tube structure and cannot be applied to cleaning an exhaust gas heat recovery device.

  A cleaning device that cleans the heat exchanger tube group by spraying cleaning water from a lance movable along the tube group of the heat exchanger is also known (for example, Patent Document 2). However, in order to apply such an apparatus, it is necessary to secure a space for inserting a lance between the tube groups, and there is a problem that it cannot be applied to an existing heat exchanger as it is.

Japanese Patent Laid-Open No. 10-265982 JP 2001-12894 A

  The present invention has been made in view of the above problems, and it is possible to clean dust that adheres to and accumulates on the surface of a heat transfer tube inside an exhaust gas heat recovery device, and a cleaning device for an exhaust gas heat recovery device that does not have an unwashed portion. The purpose is to provide.

  The present invention has been made to solve the above problems. That is, the present invention is a cleaning device for cleaning the outer surfaces of a plurality of heat transfer tubes arranged vertically in an exhaust gas heat recovery device, provided in a direction orthogonal to the heat transfer tubes, and vibrations of the heat transfer tubes An anti-vibration plate, a cleaning water supply pipe, and a pipe connected to the cleaning water supply pipe, arranged between the heat transfer pipes in a direction perpendicular to the length direction of the heat transfer pipes and parallel to the exhaust gas flow, A flexible tube provided with a washing water injection hole, and a support tube disposed along a length direction of the flexible tube, the flexible tube being heat resistant and corrosion resistant, The washing water is jetted obliquely upward from the washing water jet hole toward the vibration preventing plate. Here, in the present specification, the orthogonal direction includes not only exactly the orthogonal direction but also includes substantially the orthogonal direction as long as there is no trouble in operation of the apparatus, and includes the substantially orthogonal direction. The parallel direction includes not only the exact parallel direction but also the substantially parallel direction, and includes the substantially parallel direction.

  In one embodiment of the exhaust gas heat recovery device cleaning device of the present invention, it is preferable that the flexible tube is a fluororesin tube.

  In one form of the cleaning apparatus for an exhaust gas heat recovery device of the present invention, the cleaning water supply pipe is arranged in parallel to the length direction of the heat transfer tube, and the cleaning water is injected from the upstream side of the exhaust gas flow into the heat transfer tube. It is preferable to have an injection nozzle that performs this.

  ADVANTAGE OF THE INVENTION According to this invention, the washing | cleaning apparatus of the waste gas heat recovery device which makes it possible to wash | clean the dust adhering to and depositing on the heat exchanger tube surface inside the exhaust gas heat recovery device, and has no unwashed part can be provided.

It is a conceptual diagram explaining the washing | cleaning apparatus of the waste gas heat recovery device which concerns on this invention. It is a conceptual diagram explaining the cross section by II-II of FIG. It is a conceptual diagram explaining the cross section of a flexible tube. It is the perspective view which expands and demonstrates the state which the washing | cleaning apparatus based on this invention decomposed | disassembled, and the assembled state (dashed-dot chain line). It is a conceptual diagram explaining the effect | action of the washing | cleaning apparatus which concerns on this invention.

  Hereinafter, the cleaning apparatus for an exhaust gas heat recovery device according to the present invention will be described in more detail. The present invention is not limited to the following embodiments.

  1 and 2 show one embodiment of a cleaning apparatus for an exhaust gas heat recovery device according to the present invention. The cleaning apparatus 1 shown in FIGS. 1 and 2 is installed in the exhaust gas heat recovery unit 200, and includes cleaning water supply pipe 10, flexible tube 11, support tube 12, and vibration prevention plate as main components. 13.

  The exhaust gas 100 flows into the exhaust gas heat recovery device 200 to which the cleaning device 1 according to the present invention is applied. A plurality of heat transfer tubes 2 are arranged in the exhaust gas heat recovery device 200 in the vertical direction, and the upper end of each heat transfer tube 2 is connected to the upper header 16. Although not shown in detail, the upper header 16 is a hollow plate-like body and is provided with an inlet for introducing cooling water. After the cooling water is introduced into the upper header 16, it flows down inside each heat transfer tube 2. The cooling water flowing from above to below and the exhaust gas 100 flowing from upstream to downstream perform heat exchange via the wall surface of the heat transfer tube 2. Through this heat exchange, the thermal energy of the exhaust gas 100 is taken into the cooling water in the heat transfer tube and recovered. The cooling water that has passed through each heat transfer tube 2 is collected in one tube and supplied to boiler feed water or the like (not shown).

The exhaust gas 100 is a combustion exhaust gas containing a corrosive gas such as SO ₃ discharged from a boiler or the like. The temperature of the exhaust gas 100 at the inlet of the heat recovery device is 130 to 250 ° C., and the flow rate is 8 to 15 m / s. The exhaust gas 100 contains components such as SO _x , CO ₂ , CO, and dust. In particular, SO ₃ is highly corrosive and has the property of causing dew condensation below the acid dew point and causing severe corrosion of the heat transfer surface. Further, dust contained in the exhaust gas 100 adheres to and accumulates on the outer surface of the heat transfer tube. Inside the heat recovery unit, 20 to 900 heat transfer tubes 2 are arranged in the vertical direction, and the interval between the heat transfer tubes is about 8 to 10 mm. Inside the heat recovery unit, a plurality of rows of heat transfer tubes 2 are arranged in a direction parallel to the flow of the exhaust gas 100. Preferably, the heat transfer tubes 2 are arranged as 20 to 300 columns and 20 to 30 rows. The flow of the exhaust gas 100 in the heat recovery device is in a horizontal direction and is a direction orthogonal to the length direction of the heat transfer tube 2.

  The vibration prevention plate 13 prevents vibration by supporting the heat transfer tube 2 and prevents damage to the heat transfer tube 2. The vibration preventing plates 13 are arranged in parallel with a distance from each other in the direction perpendicular to the length direction of the heat transfer tube 2. The interval between the vibration preventing plates 13 is preferably 1000 to 2000 mm. In addition, the vibration preventing plate 13 is formed with a through hole for allowing the heat transfer tube 2 to pass therethrough. The number of through holes is the same as the number of heat transfer tubes 2. The vibration preventing plate 13 has a length of 900 to 1400 mm, a width of 800 to 2000 mm, and a plate thickness of 10 to 20 mm, but is not limited thereto as long as vibration of the heat transfer tube 2 can be suppressed. Further, the upper header 16 provided in the exhaust gas heat recovery device 200 is used in the same manner as the vibration preventing plate 13.

  The cleaning water supply pipe 10 is a tube that supplies the cleaning water 101 to the flexible tube 11 from the outside of the heat recovery unit 200. The cleaning water supply pipe 10 is arranged in parallel to the length direction of the heat transfer tube 2. The cleaning water supply pipe 10 is installed on the upstream side of the exhaust gas flow of the heat transfer tube group composed of the plurality of heat transfer tubes 2. The cleaning water supply pipe 10 is connected to an external cleaning water supply source (not shown) via a valve 20. The cleaning water 101 supplied from the cleaning water supply source is normal water or an alkaline aqueous solution. Examples of the alkaline aqueous solution include aqueous solutions of sodium hydroxide, potassium hydroxide, calcium carbonate, and potassium carbonate. The pH and concentration of the alkaline aqueous solution are adjusted as appropriate. A pump 21 is connected to the cleaning water supply pipe 10 via a pipeline. The other end of the cleaning water supply pipe 10 is attached to a duct in order to prevent vibration during spraying of cleaning water. As the cleaning water supply pipe 10, a heat-resistant and corrosion-resistant alloy such as SUS316L or Hastelloy (registered trademark) C22 can be used. The diameter of the cleaning water supply pipe 10 is 60 to 120 mm. A plurality of branch pipes 23 are provided at intervals on the outer wall surface of the cleaning water supply pipe 10 on the heat transfer tube 2 side. One end of a plurality of flexible tubes 11 is connected to the branch pipe 23. The branch pipe 23 preferably has a diameter of 8 to 30 mm and a length of 40 to 100 mm. The connection between the cleaning water supply pipe 10 and the flexible tube 11 does not have to be performed via the branch pipe 23 and can be performed by other general means as long as the object of the present invention is achieved. it can.

  The cleaning water supply pipe 10 also includes an injection nozzle 17 that injects the cleaning water 101 from the upstream side of the exhaust gas flow to the heat transfer pipe 2. The injection nozzle 17 is arranged in alignment on the heat transfer tube group side of the outer wall surface of the cleaning water supply pipe 10. The injection nozzles 17 are preferably arranged at an interval of 750 to 1000 mm. As the injection nozzle 17, a general liquid injection nozzle for water, an alkaline aqueous solution or the like can be used. The spray nozzle 17 sprays the cleaning water 101 in a conical shape having an angle of 30 to 45 ° from the central axis, and the spray water amount is 10 to 35 L / min. Since the cleaning water supply pipe 10 includes the injection nozzle 17, the cleaning water 101 can be sprayed from the outside of the heat transfer tube group toward the heat transfer tube group, and the heat transfer tube 2 positioned on the exhaust gas upstream side is cleaned. can do.

  The flexible tube 11 includes a plurality of washing water injection holes 15, and the washing water 101 supplied from the washing water supply pipe 10 is obliquely upward toward the vibration preventing plate 13 through the washing water spray holes 15. To spray. One end of the flexible tube 11 is connected to the cleaning water supply pipe 10 via a branch pipe 23. The other end side of the flexible tube 11 is passed between the heat transfer tubes 2 so as to escape from the upstream side to the downstream side of the exhaust gas 100. The flexible tube 11 is disposed between the heat transfer tubes 2 in a direction orthogonal to the length direction of the heat transfer tubes 2 and in a direction parallel to the flow of the exhaust gas 100. The flexible tube 11 is supported between the heat transfer tubes 2 by the support 14 together with the support tube 12, but may be supported between the heat transfer tubes 2 by other general means.

  Each flexible tube 11 is also arranged below the vibration preventing plate 13 at a predetermined interval in the length direction of the heat transfer tube 2. The distance between the upper end of the flexible tube 11 and the lower surface of the vibration preventing plate 13 is preferably 30 to 50 mm, and more preferably 35 to 40 mm. Between the heat transfer tubes 2, the flexible tube 11 may or may not be in contact with the heat transfer tube 2. The flexible tube 11 has a diameter of 8 to 10 mm and a length of 900 to 140 mm. However, the flexible tube 11 is not limited to this as long as there is no problem in operation of the cleaning device 1 according to the present invention. The flexible tube 11 is disposed with 3 to 6 rows of heat transfer tubes 2, preferably 4 rows of heat transfer tubes 2 interposed therebetween.

  The washing water injection holes 15 are drilled in the side wall of the flexible tube 11 at intervals of 30 to 40 mm. The washing water injection hole 15 is disposed between the heat transfer tubes 2 on the side wall of the flexible tube 11. The diameter of the washing water injection hole 15 is preferably 1.5 to 3 mm, more preferably 1.8 to 2.2 mm. The cleaning water injection holes 15 are not arranged in a concentrated manner in one direction, but are alternately arranged on the left and right with respect to the central axis of the flexible tube 11 when the cleaning water proceeds on the flexible tube 11 in the flow direction of the cleaning water. Is done. Further, since the cleaning water injection holes 15 are arranged between the heat transfer tubes 2, the cleaning water can be injected into the gaps between the rows of the heat transfer tubes 2, and one of the cleaning water is also applied to the heat transfer tubes 2 on the downstream side of the gas flow. There is an effect of cleaning the heat transfer tube 2 by colliding with each other.

  As shown in FIG. 3, the cleaning water injection hole 15 is provided in a direction that forms an angle of θ with the center line l in the vertical direction. The angle θ at which the cleaning water injection hole 15 is provided is preferably 30 to 60 ° C, and more preferably 45 ° C. Accordingly, the cleaning water can be jetted obliquely upward from the cleaning water injection hole 15 toward the vibration preventing plate 13 provided on the upper side of the flexible tube 11, and the cleaning water 101 collides with the vibration preventing plate 13. And can be dispersed over a wide range.

The flexible tube 11 is made of a heat resistant and corrosion resistant material. By configuring the flexible tube 11 with a heat-resistant and corrosion-resistant material, it is possible to prevent damage due to contact with high-temperature exhaust gas at 200 ° C. and to prevent corrosion due to corrosive substances such as SO _3. .

  The flexible tube 11 is also preferably a fluororesin tube. A fluororesin tube is a tube formed using only a fluororesin. As described above, the exhaust gas heat recovery device has a high temperature and an acid corrosion environment because the exhaust gas from the boiler flows in. Accordingly, the heat transfer tube 2 may be coated or lined with a fluororesin or may be a fluororesin tube in order to have a heat resistance function and acid corrosion resistance. In such a case, if a metal tube such as SUS316L or Hastelloy (registered trademark) C22 is inserted between the heat transfer tubes 2, the fluororesin constituting the heat transfer tube 2 may be damaged by friction. When the heat transfer tube 2 and the flexible tube 11 are formed of the same material at least on the outer surface, there is an effect that they are not worn or damaged even if they are in contact with each other.

  As the fluororesin, PTFE and PFA having heat resistance of about 250 ° C. or higher are suitable. According to the cleaning apparatus 1 of the present invention, the heat transfer tube 2 can be efficiently cleaned by spraying the cleaning water inside the heat transfer tube group, so that dust accumulates and clogging between the heat transfer tubes 2 occurs. Can be prevented.

  The support tube 12 has a function of preventing the flexible tube 11 from being bent. The support tube 12 is disposed along the flexible tube 11 between the heat transfer tubes 2. As the support tube 12, SUS316L, Hastelloy (registered trademark) C22, a steel bar having a fluororesin lining applied to the entire surface, or the like can be used. The diameter of the support tube 12 is 8 to 10 mm and the length is 900 to 1400 mm, but is not limited to this as long as the benefits of the present invention are not impaired. The support tube 12 is preferably made of a heat-resistant and corrosion-resistant material made of the same material as the flexible tube 11, and more preferably made of a fluororesin made of the same material as the flexible tube 11. By forming the support tube 12 and the flexible tube 11 from the same material, there is an effect that they are not worn or damaged even if they are in contact with each other. By supporting the support tube 12 in contact with the flexible tube 11, it is possible to prevent the flexible tube 11 from being bent and prevent the spray angle of the cleaning water from deviating.

  Next, the exhaust gas heat recovery device cleaning device 1 of the present embodiment will be described in more detail with reference to FIG. In the cleaning device 1 of the present embodiment, the flexible tube 11 and the support tube 12 are supported between the heat transfer tubes 2 by the support 14. In FIG. 4, the flexible tube 11 and the support tube 12 are removed from the support 14, and the support 14 is removed from the vibration preventing plate 13. A state in which the flexible tube 11 and the support tube 12 are attached to the support 14 and the support 14 is attached to the vibration preventing plate 13 is indicated by a one-dot chain line. In FIG. 4, only one flexible tube 11 connected to the cleaning water supply pipe 10 is shown, but actually, a plurality of flexible tubes 11 are connected to the cleaning water supply pipe 10. Has been. FIG. 4 is an enlarged view of a part of the cleaning device 1 of the present embodiment. The cleaning device 1 of the present embodiment includes a heat transfer tube 2, a flexible tube 11, a support tube 12, and a support (not shown). A body 14 is further provided.

  A plurality of holes 27 are perforated in the support 14, and holes 26 corresponding to the holes 27 are provided on the side surface of the vibration preventing plate 13. The support body 14 is attached to each of both side surfaces of the vibration preventing plate 13 by inserting and fixing the set screws 25 into the holes 26 and 27. The support plate 14 may be attached to the vibration preventing plate 13 by other general means besides the set screw 25. A through hole 28 is provided in the support 14, and a through hole 29 is provided adjacent to the through hole 28. The flexible tube 11 is passed through the through holes 28 of the two supports 14 fixed to both side surfaces of the vibration preventing plate 13. Similarly, the support tube 12 is passed through and supported by the through holes 29 of the two supports 14. The through hole 28 and the flexible tube 11, and the through hole 29 and the support tube 12 may be fixed by means such as welding.

  Next, the operation of the cleaning apparatus 1 according to the present invention will be described with reference to FIG. In FIG. 5, the exhaust gas 100 flows in the front direction from the back of the figure. The washing water 103 injected obliquely upward from the washing water injection hole 15 and into the gaps between the rows of the heat transfer tubes 2 collides with the vibration prevention plate 13, and travels along the vibration prevention plate 13 by the spray pressure and the flow of the exhaust gas 100. Furthermore, it is widely dispersed. Moreover, since the washing water 103 flows down along the outer surface of the heat transfer tube 2 by gravity, dust adhering to the outer surface can be removed. Here, referring to FIG. 2, the cleaning water sprayed from α in the cleaning water spray hole 15 is dispersed in a wide range and can reach the cleaning range indicated by A in the tube group. The cleaning range A is, for example, an area of approximately 140 mm × 70 mm when the exhaust gas flow rate is 10 m / s and the amount of water injected per cleaning water injection hole is about 1 L / min. The cleaning range A corresponding to each cleaning water injection hole 15 is combined, and the flexible tube 11 and the cleaning water injection hole 15 are arranged so that there is no portion where the cleaning water does not reach. Thereby, it becomes possible to wash | clean enough even to the inside of a heat exchanger tube group, and an unwashed part can be eliminated.

  The water pressure of the washing water that passes through the flexible tube 11 is preferably 0.15 to 0.25 MPa. This is because the water pressure is less than the permissible pressure of the fluororesin tube and the water pressure is such that the cleaning water can be effectively injected from the cleaning water injection hole 15. Moreover, it is preferable that the amount of jet water per one wash water jet hole 15 is 0.8 to 1.2 L / min.

  The cleaning device 1 according to the present invention is used for cleaning the heat transfer tube 2 during operation of the exhaust gas heat recovery device. Washing is performed intermittently, preferably 2-3 times a day. By performing the cleaning during the operation of the heat recovery device, the cleaning water can be diffused over a wide range using the exhaust gas flow, and the heat transfer tube group can be cleaned efficiently.

  According to the cleaning device of the present invention, dust adhering to the outer surface of the heat transfer tube can be efficiently cleaned by spraying the cleaning water from the inside of the heat transfer tube group. For this reason, an unwashed part does not occur and the heat recovery efficiency of the heat recovery device can be increased. Further, even when the interval between the heat transfer tubes is narrow, clogging due to dust accumulation can be prevented, and gas side pressure loss can be reduced. In the cleaning apparatus according to the present invention, since the tube inserted between the heat transfer tubes is flexible, the heat transfer tubes are not damaged even if the interval between the heat transfer tubes is narrow. Furthermore, since the flexible tube is heat resistant and corrosion resistant, the cleaning device according to the present invention also has an effect that it can be applied to a heat recovery device into which high temperature corrosive exhaust gas flows.

  ADVANTAGE OF THE INVENTION According to this invention, the washing | cleaning apparatus of the waste gas heat recovery device which enables washing | cleaning of the dust adhering to and depositing on the surface of a heat exchanger tube, and having no unwashed part can be provided.

DESCRIPTION OF SYMBOLS 1 Washing apparatus 2 Heat transfer tube 10 Pipe for washing water supply 11 Flexible tube 12 Support tube 13 Vibration prevention plate 14 Support body 15 Washing water injection hole 16 Upper header 17 Injection nozzle 20 Valve 21 Pump 23 Branch pipe 25 Stop screw 26 Hole 27 Hole 28 Through hole 29 Through hole 100 Exhaust gas 101 Washing water 102 Washing water injection direction 103 Washing water 200 Heat recovery device α Washing water injection hole A Washing range l Vertical centerline θ Angle formed with the centerline

Claims (3)

A cleaning device for cleaning the outer surfaces of a plurality of heat transfer tubes arranged vertically in an exhaust gas heat recovery device,
An anti-vibration plate that is provided in a direction orthogonal to the heat transfer tube and suppresses vibration of the heat transfer tube;
A pipe for supplying cleaning water;
A flexible tube connected to the cleaning water supply pipe, arranged between the heat transfer tubes in a direction orthogonal to the length direction of the heat transfer tubes and in a direction parallel to the exhaust gas flow, and having a plurality of cleaning water injection holes;
A support tube disposed along the length direction of the flexible tube, the flexible tube being heat-resistant and corrosion-resistant, obliquely from the washing water injection hole toward the vibration preventing plate Cleaning device for exhaust gas heat recovery device that injects cleaning water upward.   The exhaust gas heat recovery device cleaning device according to claim 1, wherein the flexible tube is a fluororesin tube. 2. The exhaust gas heat recovery according to claim 1, wherein the cleaning water supply pipe is disposed in parallel with a length direction of the heat transfer tube, and includes an injection nozzle that injects cleaning water from the exhaust gas flow upstream side to the heat transfer tube. Cleaning equipment.

Images