JP2018080852A - Exhaust heat recovery boiler and manufacturing method for the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an exhaust heat recovery boiler capable of suppressing self-excited vibration of heat transfer pipes.SOLUTION: An exhaust heat recovery boiler comprises: a heat transfer pipe group consisting of a plurality of fin tubes 3 arranged so as to be orthogonal to exhaust gas flow; a plurality of perforated plates being formed with a plurality of holes into which each of the fin tubes 3 is inserted and provided with predetermined intervals in a longitudinal direction of the fin tubes 3; and support plates 20 being disposed among the plurality of perforated plates and disposed so as to be brought into contact with a part of the plurality of fin tubes 3. The fin tubes 3 are disposed in a zigzag manner in a vertical direction and in a horizontal direction. The support plates 20 are provided so as to obliquely extend in the vertical direction among the fin tubes 3 adjacent to one another.SELECTED DRAWING: Figure 5

Description

  The present invention relates to an exhaust heat recovery boiler having a structure for supporting a plurality of heat transfer tubes and a method for manufacturing the same.

  An exhaust heat recovery boiler (HRSG) is known (Patent Document 1). The exhaust heat recovery boiler includes a large number of heat transfer tubes, and each heat transfer tube is supported by a perforated plate arranged at a predetermined position in the longitudinal direction of the heat transfer tube. The perforated plate has a plurality of holes corresponding to the heat transfer tubes, and supports the heat transfer tubes in place by inserting the heat transfer tubes into the holes.

JP 2003-120901 A

  With the increase in the size of the exhaust heat recovery boiler, the heat transfer tubes become longer, and the distance between the perforated plates (support span) is longer, for example, 3 m to 4 m. Also, each heat transfer tube is often arranged so as to be orthogonal to the exhaust gas flow direction, and self-excited vibration of the heat transfer tube due to Karman vortex generated in the wake of the heat transfer tube due to the exhaust gas flow occurs, and the heat transfer tube is in contact with the porous plate. There is a concern that abrasion may occur between the two and damage.

In addition, a part of the exhaust gas component adheres to the heat transfer tube, and the adhering matter narrows the flow area of the exhaust gas, thereby increasing the flow rate of the exhaust gas. Increasing the flow rate of exhaust gas makes it easier to generate self-excited vibration due to increased excitation force of the heat transfer tube and generation of Karman vortex, which may further increase the vibration amplitude and increase wear damage of the heat transfer tube. is there. For example, sulfur oxide (SOx) exists in the exhaust gas after burning fuel containing sulfur such as blast furnace gas and oil. In this case, SO ₂ in the exhaust gas reacts with ammonia injected for denitration to generate ammonium hydrogen sulfate and the like, and ammonium hydrogen sulfate and the like are deposited on the heat transfer tube depending on conditions such as concentration and exhaust gas temperature. It becomes a deposit and adheres to the heat transfer tube.

  This invention is made | formed in view of such a situation, Comprising: It aims at providing the exhaust heat recovery boiler which can suppress the self-excited vibration of a heat exchanger tube, and its manufacturing method.

In order to solve the above problems, the exhaust heat recovery boiler and the manufacturing method thereof according to the present invention employ the following means.
That is, the exhaust heat recovery boiler according to the present invention is formed with a heat transfer tube group composed of a plurality of heat transfer tubes arranged orthogonal to the flow of the exhaust gas, and a plurality of holes through which the heat transfer tubes are inserted, A plurality of perforated plates provided at predetermined intervals in the longitudinal direction of the heat transfer tube group; and a support plate disposed between the perforated plates and disposed to contact at least a part of the heat transfer tubes. It is characterized by.

The perforated plate has a plurality of holes through which the heat transfer tubes are inserted, and supports the heat transfer tubes. A plurality of perforated plates are provided at predetermined intervals in the longitudinal direction of the heat transfer tube group. Between the perforated plates, a support plate is provided so as to be in contact with the heat transfer tube. Thus, by providing the support plate that supports the heat transfer tube between the perforated plates, the length of the support interval at which the heat transfer tube can freely vibrate can be shortened. By reducing the interval between the perforated plates, it is possible to reduce the possibility that the heat transfer tube will cause self-excited vibration due to the exhaust gas flow.
The support plate only needs to be in contact with the heat transfer tube during operation of the exhaust heat recovery boiler, and may be non-contact in the cold state before the start of operation.

  Furthermore, in the exhaust heat recovery boiler of the present invention, the heat transfer tubes are arranged in a staggered manner in the vertical direction and the horizontal direction, and the support plate extends obliquely between the adjacent heat transfer tubes with respect to the vertical direction. It is characterized by being provided.

  Since the support plate is provided so as to extend obliquely between the adjacent heat transfer tubes with respect to the vertical direction, the efficiency per one support plate is made to contact a plurality of heat transfer tubes from below or above in the vertical direction. Since a plurality of heat transfer tubes can be well supported, the support plate can be easily arranged.

  Furthermore, the exhaust heat recovery boiler according to the present invention is characterized by including a frame body to which both end portions of the support plate are fixed.

  Since the structure for fixing the support plate is provided between the perforated plates, it is not necessary to have a function of inserting each heat transfer tube into each hole and supporting each heat transfer tube at a fixed position like the perforated plate. Then, the structure which hold | maintains a support plate simply can be implement | achieved by providing the frame which fixes the both ends of a support plate so that the circumference | surroundings of the several heat exchanger tube supported by the porous plate may be enclosed.

  Furthermore, in the exhaust heat recovery boiler according to the present invention, the frame body has a rectangular shape in which a horizontal portion and a vertical portion are connected, and the horizontal portion and the vertical portion are connected so as to be relatively movable and rotatable. It is characterized by.

  Since the horizontal portion and the vertical portion of the frame body are connected so as to be relatively movable, the frame body can follow the heat transfer tube group even if the heat transfer tube group is thermally deformed, and the heat transfer tube is not damaged. Further, even if a difference in thermal expansion occurs due to a temperature difference between the horizontal portion and the vertical portion, the frame body does not damage the heat transfer tube because they are not constrained to each other.

  Furthermore, the exhaust heat recovery boiler of the present invention includes a drift prevention plate disposed on one side and the other side of the heat transfer tube group perpendicular to the longitudinal direction of the heat transfer tubes to prevent the exhaust gas flow from drifting. The frame is fixed to the drift prevention plate.

Since the frame body is fixed to the drift prevention plate installed on the side of the heat transfer tube group, the frame body can be fixed at a fixed position with a simple configuration. Thereby, since the movement of the frame body and the support plate in the heat transfer tube longitudinal direction is restricted, the vibration reduction of the heat transfer tube can be more effectively exhibited.
For example, a notch or a slit is provided in the drift prevention plate and the frame body is fixed by inserting the end of the frame.

  Furthermore, in the exhaust heat recovery boiler of the present invention, the support plate is in contact with the heat transfer tube from below in the vertical direction.

  Since the support plate can favorably support the heat transfer tube bent downward in the vertical direction by its own weight while maintaining reliable contact with the heat transfer tube from below, the heat transfer tube is less likely to cause self-excited vibration due to the exhaust gas flow. be able to.

  Furthermore, the exhaust heat recovery boiler of the present invention includes a support beam extending in a horizontal direction so as to connect the upper ends of the perforated plates, and the frame body is supported by being suspended from the support beam. It is characterized by being.

  The upper ends of the perforated plates are connected to each other, and the frame body is fixed so as to be suspended from the support beam extending in the horizontal direction. As described above, since the frame can be fixed without using the drift prevention plate, it is possible to reduce the load (frame body and support plate) applied to the drift prevention plate and eliminate the necessity of reinforcing the drift prevention plate. Can do.

  Furthermore, in the exhaust heat recovery boiler according to the present invention, the end in the width direction of the support plate is formed in an R shape having a roundness in the thickness direction.

  Since the R shape and the taper having the roundness in the thickness direction are provided at the end in the width direction of the support plate, the heat transfer tube is not damaged when the support plate is inserted between the heat transfer tubes.

  Furthermore, in the exhaust heat recovery boiler of the present invention, the support plate is formed with a plurality of holes or notches penetrating in the thickness direction.

  By providing a plurality of holes or notches in the support plate, the exhaust gas flow path was secured. Thereby, it can suppress as much as possible that a support plate inhibits the flow of exhaust gas, the flow resistance at the time of exhaust gas passing through can be reduced, and pressure loss can be reduced.

  Furthermore, in the exhaust heat recovery boiler of the present invention, the support plate has a wave shape in which peaks and valleys are alternately provided in the longitudinal direction.

  By making the support plate corrugated, it is possible to increase the probability of contact while improving the degree of freedom of deformation of the support plate with respect to the heat transfer tube.

  Furthermore, in the exhaust heat recovery boiler of the present invention, the support plate has a shape in which a central portion in the width direction is convex.

  Since the central part in the width direction of the support plate is convex, the distance between the heat transfer tube and the contact part of the support plate is shortened to increase the probability of contact, and the convex part is in close contact with the heat transfer tube by elastic force. Can touch.

  Furthermore, in the exhaust heat recovery boiler according to the present invention, the support plate is disposed in the center between the adjacent porous plates.

By arranging the support plate in the center between adjacent perforated plates, the length of the support interval at which the heat transfer tubes can vibrate freely can be shortened using the minimum number of support plates, and the heat transfer tubes can be self-excited. Vibration can be suppressed.
A plurality of support plates may be provided between the perforated plates. In this case, it is preferable to provide support plates at regular intervals.

  Furthermore, in the exhaust heat recovery boiler of the present invention, the exhaust gas is denitrated with ammonia and contains sulfur oxide, and the support plate has a predetermined temperature between 100 ° C. and 250 ° C. It is provided in the area | region made into the range.

When denitration with ammonia is performed, the exhaust gas contains ammonia that has not been recovered by denitration reaction, reacts with the SOx content contained in the exhaust gas, and in a predetermined temperature range between 100 ° C and 250 ° C. Ammonium hydrogen sulfate may adhere to the heat transfer tube. By providing the support plate in this region, it is possible to suppress the self-excited vibration of the heat transfer tube from being promoted even if the exhaust gas flow path is narrowed by the attached ammonium hydrogen sulfate and the flow rate of the exhaust gas is increased.
In addition, a support plate may be provided only in the area | region where exhaust gas temperature was made into the predetermined temperature between 100 degreeC-250 degreeC, and may be provided so that this area | region may be included.

  Moreover, the manufacturing method of the exhaust heat recovery boiler of the present invention includes a step of installing a heat transfer tube group composed of a plurality of heat transfer tubes arranged orthogonal to the flow of the exhaust gas, and a plurality of the heat transfer tubes inserted therein. A step of installing a plurality of perforated plates in which holes are formed with a predetermined interval in the longitudinal direction of the heat transfer tube group, and a step of installing a support plate between the perforated plates so as to contact the heat transfer tubes It is characterized by having.

  Since the support plate for supporting the heat transfer tube is provided between the perforated plates, the possibility that the heat transfer tube causes self-excited vibration due to the exhaust gas flow can be reduced.

It is the side view showing the schematic structure of the exhaust heat recovery boiler concerning one embodiment of the present invention. It is the perspective view which showed the fin tube. The fin tube arrange | positioned in zigzag form is shown, (a) is a front view which shows the state by which the fin tube was penetrated with respect to the perforated plate, (b) is the cross section which showed the deposit | attachment adhering to the fin tube FIG. It is the side view which showed the support plate provided between the perforated plates. It is the front view which showed the specific structure of the arrangement | sequence of a support plate. It is the front view which showed the connection structure of the frame. It is the side view which showed the shape of the edge part of a support plate. The modification of a support plate is shown, (a) is the top view which formed the several hole, (b) is the top view which formed the some notch. It is the top view which showed the fixation structure of the frame. The contact state of a fin tube and a support plate is shown, (a) is a cross-sectional view showing a state before operation, and (b) is a cross-sectional view showing a state during operation. It is the perspective view which showed the support beam provided in the perforated plate. It is sectional drawing which showed the support plate which contacts from the upper direction of a fin tube. It is the perspective view which showed the 1st modification of the support plate. It is sectional drawing which showed the contact with a fin tube and the support plate of FIG. It is the perspective view which showed the 2nd modification of the support plate. It is sectional drawing which showed the contact with a fin tube and the support plate of FIG. It is the perspective view which showed the frame suspended from the support beam.

Embodiments according to the present invention will be described below with reference to the drawings.
FIG. 1 shows a heat recovery steam generator (HRSG) 1. On the upstream side of the exhaust gas flow of the exhaust heat recovery boiler 1, a gas turbine (not shown) to which combustion gas combusted by a combustor (not shown) is introduced, and nitrogen contained in the exhaust gas discharged from the gas turbine in the exhaust heat recovery boiler A denitration device (not shown) for treating oxide (NOx) is provided. The denitration apparatus employs a method of denitration using ammonia.

  A plurality of fin tubes (heat transfer tubes) 3 are provided in the horizontal direction inside the heat exchange vessel 2 in which the exhaust gas flows in the vertical direction. That is, the fin tube 3 is disposed orthogonal to the flow of exhaust gas. Each fin tube 3 is connected to the outside of the heat exchange vessel 2 via a U-shaped tube 4.

  As shown in FIG. 2, the fin tube 3 stands upright on the outer peripheral surface of a circular tube 5 made of stainless steel, low alloy steel or the like according to the operating temperature with a short interval in the axial direction. This is a fixed structure. For example, water or steam supplied to a boiler or a steam turbine flows through the circular pipe 5. In the present embodiment, the fins 6 are serrated fins having a bowl shape and gear-like irregularities formed on the outer peripheral edge thereof, but are not limited to a disc shape having irregularities. . Further, there may be only the circular pipe 5 without fins.

  An exhaust gas inflow duct 8 and an exhaust gas outflow duct 9 are provided at the bottom and the top of the heat exchange vessel 2, respectively. A high temperature exhaust gas that has finished work in a gas turbine (not shown) flows into the heat exchange vessel 8 from the exhaust gas inflow duct 8. 2 passes from below in the vertical direction to above and flows out from the exhaust gas outflow duct 9. Then, when the high temperature exhaust gas flows around the fin tube 3 whose heat transfer area with the exhaust gas is increased by the fins 6, the fluid (water, steam, etc.) flowing inside the circular tube 5 exchanges heat with the exhaust gas. Heated. Thus, the amount of heat held by the exhaust gas is efficiently recovered and effectively used.

  The length in the longitudinal direction of the straight portion of the fin tube 3 is elongated, and there are some that reach 20 m or more in the long one. For this reason, there exists a possibility that the intermediate part of the heavy fin tube 3 including the fluid which flows through an inside may bend below. Therefore, the load of the fin tube 3 is supported by the plurality of perforated plates 11 installed at predetermined intervals in the longitudinal direction of the fin tube 3. The interval between the perforated plates 11 is, for example, 2 m to 5 m. The perforated plate 11 is a flat plate member having a predetermined thickness, and a plurality of holes 12 (see FIG. 1) through which the fin tubes 3 are inserted are formed. The perforated plate 11 is suspended from a ceiling structural member 13 or the like disposed inside the heat exchange vessel 2 by a hanging tool 14, and when the temperature of each component rises, the respective components due to the difference in thermal expansion are mutually connected. I try not to interfere.

As shown in FIG. 3, the fin tubes 3 are supported at a fixed position with respect to the perforated plate 11 in a state of being densely arranged in a staggered manner in the vertical direction and the horizontal direction. As shown by the arrows in FIG. 3A, the exhaust gas flows upward from the lower side of the perforated plate 11 in the vertical direction.
By supporting the fin tube 3 between the perforated plates 11, the support interval between the adjacent perforated plates 11 becomes a support length at which the fin tube 3 can freely vibrate. The fin tube 3 is vibrated by the fluid force of the exhaust gas flow, but the support length of the fin tube 3 and the flow rate of the exhaust gas around the fin tube 3 are greatly affected. Moreover, as shown in FIG.3 (b), the deposit | attachment 16 may arise in the outer periphery of the fin tube 3 by the driving | operation of the exhaust heat recovery boiler 1 by the property of waste gas.

Typically, the deposit 16 includes acidic ammonium hydrogen sulfate. Acidic ammonium hydrogensulfate is combusted when a denitration device using ammonia is installed upstream of the exhaust heat recovery boiler 1 and the fuel is a fuel containing a relatively large amount of sulfur such as blast furnace gas or oil. Prominently generated in exhaust gas.
Ammonium hydrogen sulfate is a chemical reaction (NH) of ammonia (NH ₃ ) sprayed into exhaust gas as a reducing agent for a denitration catalyst that cannot be recovered without being used in the reductive denitration reaction and SOx in the exhaust gas. ₃ + H ₂ SO ₄ ) generates ammonium hydrogen sulfate (NH ₄ HSO ₄ ). Ammonium hydrogen sulfate begins to precipitate at about 100 ° C. to 250 ° C., depending on the concentration in the exhaust gas. When the deposit 16 is generated in this way, the flow path of the exhaust gas between the fin tubes 3 is narrowed, and the flow velocity of the exhaust gas is increased. As a result, the excitation force of the fin tube 3 and the generation of Karman vortex are increased. The self-excited vibration of the tube 3 is likely to occur. When the self-excited vibration of the fin tube 3 is generated, the amplitude of the vibration is increased. Therefore, the fin tube 3 may increase wear damage at the support portion of the porous plate 11. When wear damage occurs in the support portion of the perforated plate 11, the fin tubes 3 are closely arranged in a staggered manner, so that the wear damaged fin tube 3 near the support portion of the perforated plate 11 is replaced. It is not easy. Therefore, in the present embodiment, as shown in FIG. 4, the support plate 20 is installed between the perforated plates 11.

By providing the support plate 20 that supports the fin tube 3 between the perforated plates 11, the length of the support interval at which the fin tube 3 can freely vibrate can be shortened. Even when the interval between adjacent porous plates 11 is large, the support interval length of the fin tube 3 that affects the generation of self-excited vibration can be shortened by providing the support plate 20. For this reason, the possibility that the fin tube 3 causes self-excited vibration due to the exhaust gas flow can be reduced.
As shown in FIG. 4A, the support plate 20 is preferably disposed in the vicinity of the approximate center between the adjacent porous plates 11. However, as shown in FIG. 4B, a plurality of support plates 20 may be installed between the perforated plates 11. In this case, it is preferable to install the support plates 20 at substantially equal intervals so that no self-excited vibration is generated in some fin tubes 3. The installation position and the number of the support plates 20 are appropriately adjusted according to the conditions under which the self-excited vibration of the fin tube 3 is generated.

  Alternatively, as shown in FIG. 4C, the support plate 20 may be provided in a region where the deposit 16 (see FIG. 3B) is generated and the exhaust gas flow velocity around the fin tube 3 is likely to increase. good. For example, when acidic ammonium hydrogen sulfate is generated as the deposit 16 as described above, the exhaust gas temperature is within a predetermined range where ammonium hydrogen sulfate is likely to be deposited under the operating conditions of the exhaust heat recovery boiler 1 among 150 ° C. to 250 ° C. It is provided in the temperature area. In this case, the support plate 20 may be provided only in a region where the exhaust gas temperature is in a predetermined range of 150 ° C to 250 ° C. That is, it is not necessary to provide the support plate 20 over the entire vertical and vertical direction of the fin tube 3 supported by the porous plate 11. Or you may provide the support plate 20 so that the exhaust gas temperature may include the area | region made into the temperature of the predetermined range among 150 degreeC-250 degreeC.

FIG. 5 shows a specific arrangement of the support plates 20. The support plate 20 has a plate shape having a predetermined thickness t1. In the present embodiment, for example, the support plate 20 has a width of 10 mm to 50 mm and a thickness (t1) of 3 mm to 9 mm. That is, the support plate 20 is disposed so that the wide surface faces the exhaust gas flow.
The material of the support plate 20 varies depending on the gas properties, but can be selected based on the exhaust gas temperature, for example. As an example, when the exhaust gas temperature is 350 ° C. to 400 ° C. or lower, carbon steel is used, and when it is 350 ° C. to 400 ° C. or higher and 550 ° C. to 600 ° C. or lower, 1Cr to 2Cr containing low alloy steel is used. In the case of a temperature of 550 ° C. to 600 ° C. or higher, SUS is used.

Both ends of the support plate 20 are fixed to the frame body 22 by welding. The frame 22 is a long plate-like body, and includes a horizontal portion 22a extending in the horizontal direction and a vertical portion 22b extending in the vertical direction, and is formed in a rectangular shape. The upper and lower ends of the vertical portion 22b are fixed to the left and right ends of the horizontal portion 22a.
The material of the frame 22 is the same as that of the support plate 20 described above. The frame body 22 has a thicker and thicker structure than the support plate 20 in order to hold a large number of support plates 20.

  FIG. 6 shows a specific example in which the horizontal portion 22a and the vertical portion 22b are fixed. As shown in the figure, a hole larger than the shaft diameter of the pin 25 is provided in the connection plate 24, and the horizontal portion 22a and the vertical portion 22b are supported by the pin 25 through this hole. That is, the horizontal portion 22a and the vertical portion 22b are connected to each other so that the position, relative movement, and rotation of the pin 25 can be performed by a large hole of the connection plate 24 (see the arrow in the figure). Thereby, even if the fin tube 3 is thermally deformed, the frame body 22 can follow the fin tube 3, and the fin tube 3 is not damaged by the frame body 22. Further, even if a difference in thermal expansion occurs due to a temperature difference between the horizontal portion 22a and the vertical portion 22b, the frames 22 are not torsionally deformed and the fin tubes 3 are not damaged because they are not strongly restrained from each other.

  As shown in FIG. 5, a plurality of support plates 20 are provided in parallel to each other so as to extend obliquely between the fin tubes 3 arranged in a staggered manner with respect to the vertical direction. . Specifically, each support plate 20 located on the front side of the frame body 22 in the paper surface of the figure is provided to extend obliquely upward to the right, and the back surface side of the frame body 22 in the paper surface of the figure. Each support plate 20 located at is arranged so as to extend obliquely upward to the left. Thus, by arranging the support plate 20 so as to intersect each gap between the fin tubes 3, the support plate 20 can be supported in contact with the plurality of fin tubes 3. Since a plurality of fin tubes 3 can be efficiently contacted and supported per one support plate 20, the arrangement of the support plate 20 is facilitated.

  As shown in FIG. 7, the support plate 20 is formed in an R shape having a taper shape in the thickness direction and a rounded tip. Thereby, when inserting the support plate 20 between the fin tubes 3 at the time of manufacture, the fin tubes 3 are not damaged. Further, when the exhaust gas passes, the wide surface of the support plate 20 faces the exhaust gas flow, so that each side extending in the longitudinal direction at both end portions in the width direction of the support plate 20 generates a vortex perpendicular to the exhaust gas flow. This is a region where fluid energy loss is likely to occur.

  As shown in FIG. 8A, the support plate 20 may be formed with a plurality of holes 20a penetrating in the thickness direction. The shape of the hole 20a may be a circle, an ellipse, an ellipse, or a polygon. Thereby, it can suppress as much as possible that the support plate 20 inhibits an exhaust gas flow by ensuring the flow path through which exhaust gas can pass through the support plate 20. For this reason, the flow resistance at the time of exhaust gas passage can be reduced, and the pressure loss of exhaust gas can be reduced.

Further, as shown in FIG. 8B, a plurality of notches 20b may be provided on the side portion of the support plate 20 for the same purpose. The shape of the cutout 20b may be a semicircular shape as shown in the figure, or may be an ellipse, an ellipse, or a partial shape of a polygon. By securing the flow path through which the exhaust gas can pass through the support plate 20, the flow resistance when the exhaust gas passes can be reduced, and the pressure loss of the exhaust gas can be reduced.
In addition, when the width | variety of the support plate 20 does not have big influence on exhaust gas flow, it is not necessary to provide the hole 20a and the notch 20b.

FIG. 9 shows a fixing structure of the frame body 22. The figure shows a state in which a vertically downward direction is seen from the downstream side of the exhaust gas flow, one side of the heat exchange vessel 2 is shown on the left side of the drawing, and the other side of the heat exchange vessel 2 is omitted. . On one side of the fin tube 3, a drift prevention plate 28 for preventing drift of the exhaust gas flow is provided. Similarly, a drift prevention plate 28 (not shown) is also provided on the other side of the fin tube 3. The drift prevention plate 28 is provided along the vertical direction. The drift prevention plate 28 prevents the exhaust gas from flowing in a region without the fin tube 3 while avoiding a region where the plurality of fin tubes 3 are arranged side by side and the flow resistance is increased.
As shown in the figure, the frame 22 may be fixed to the drift prevention plate 28. Specifically, the drift prevention plate 28 is provided with a notch or a slit, and is fixed by inserting an end portion of the frame body 22. Thereby, not only the vertical position support of the frame body 22 but also the movement of the support plate 20 in the longitudinal direction of the fin tube 3 is restricted, so that the length of the support interval at which the fin tube 3 can freely vibrate is reduced. Since it does not fluctuate, the vibration reduction of the fin tube 3 can be exhibited more effectively.

  FIG. 10 shows a contact state between the fin tube 3 and the support plate 20. The fin tubes 3 are densely arranged by the perforated plate 11, and the interval between the fin tubes 3 is originally narrow, and the interval between the fin tube 3 and the support plate 20 is narrow regardless of contact / non-contact. For this reason, as shown in FIG. 10A, in the cold state before the operation, since fluid (water or steam) is not supplied into the fin tube 3, the amount of deflection due to its own weight is small. The support plate 20 may not be in contact. On the other hand, when the exhaust heat recovery boiler 1 is operated, as shown in FIG. 10B, fluid (water or steam) is supplied into the fin tube 3 to increase the weight of the fin tube 3, so that the amount of deflection increases. Two points on the lower side of the fin tube 3 come into contact with the support plate 20. As shown in the figure, the fin tube 3 and the support plate 20 may not be in contact with each other before the operation, but the fin tube 3 and the support plate 20 must be in contact with each other during the operation. The relative position is determined. Of course, the fin tube 3 and the support plate 20 may be in contact before operation.

The exhaust heat recovery boiler according to the present embodiment is manufactured as follows.
First, the plurality of fin tubes 3 arranged orthogonal to the flow of exhaust gas in the heat exchange vessel 2 in which exhaust gas flows in the vertical direction of the exhaust heat recovery boiler 1 are assembled in the following process.
Then, the plurality of fin tubes 3 are inserted through the plurality of perforated plates 11 with a predetermined interval in the longitudinal direction, and arranged orthogonal to the flow of the exhaust gas. The perforated plates 11 are installed at predetermined intervals in the longitudinal direction of the plurality of fin tubes 3. Each fin tube 3 is connected to the outside of the heat exchange vessel 2 via a U-shaped tube 4.
When the exhaust heat recovery boiler 1 is operated for a long time, deposits 16 such as ammonium hydrogen sulfate are generated on the outer periphery of the fin tube 3, the exhaust gas flow path becomes narrower, and the exhaust gas flow rate increases to increase the fin tube 3. When the self-excited vibration occurs in the fin plate 3 and the fin tube 3 may increase wear damage at the support portion of the perforated plate 11, the support plate 20 is installed so as to contact the fin tube 3 between the perforated plates 11. .

According to this embodiment, there exist the following effects.
Since the support plate 20 that contacts the fin tube 3 is provided between the perforated plates 11, the length of the support interval at which the fin tube 3 can freely vibrate can be shortened even when the interval between the perforated plates 11 is large. For this reason, the possibility that the fin tube 3 may cause self-excited vibration due to the exhaust gas flow can be reduced.

  In addition, since the support plates 20 are provided so as to extend obliquely between the adjacent fin tubes 3 with respect to the vertical direction, each support plate 20 is brought into contact with the plurality of fin tubes 3 from above, A plurality of fin tubes 3 can be supported efficiently.

  Since the support plate 20 is fixed between the perforated plates 11, the structure is such that the fin tubes 3 are inserted into the respective holes as in the perforated plate 11 to support the fin tubes 3 in a fixed position. Is not necessary. Therefore, by providing the frame body 22 that fixes both ends of the support plate 20, a configuration for simply holding the support plate 20 can be realized.

  In the above embodiment, the frame body 22 is fixed using the drift prevention plate 28 as shown in FIG. 9, but the present invention is not limited to this. For example, as shown in FIG. 11, a support beam 30 extending in the horizontal direction is provided so as to connect the upper ends of the perforated plate 11. And as shown in FIG. 17, you may fix the frame 22 so that it may suspend from the support beam 30 using the frame suspension tool 15. FIG. In this case, since the support plate 20 is also suspended along with the frame body 22, the support plate 20 contacts the fin tube 3 from below as shown in FIG. Also, with this configuration, the frame body 22 can be fixed without using the drift prevention plate 28, so the load applied to the drift prevention plate 28 (the frame body 22 and the support plate 20) can be reduced to prevent the drift. The necessity of reinforcing the plate 28 can be omitted.

  In the above-described embodiment, the support plate 20 is described as a flat plate shape. However, the support plate 20 may have a shape as shown in FIG. Specifically, as shown in the figure, the support plate 20 ′ has a wave shape in which peaks and valleys are alternately provided in the longitudinal direction. The corrugated support plate 20 'can be obtained by press-molding a plate material. Thereby, as shown in FIG. 14, while maintaining the rigidity in the longitudinal direction when inserted between the fin tubes 3, the degree of freedom of deformation in the width direction of the support plate 20 ′ relative to the fin tubes 3 is improved, By reducing the distance to the fin tube 3, the probability that the support plate 20 'contacts can be increased.

  Alternatively, as shown in FIG. 15, a support plate 20 ″ having a convex shape at the center in the width direction may be used. For example, the support plate 20 ″ is welded at both ends in the width direction of two curved plates. It can be obtained by connecting with the above. As a result, as shown in FIG. 16, the distance between the fin tube 3 and the contact portion of the support plate 20 ″ is reduced to increase the probability of contact, and the convex portion at the center portion is firmly attached to the fin tube 3 by the elastic force. Can touch.

  Moreover, in the said embodiment, as shown in FIG. 1, although it demonstrated as an exhaust heat recovery boiler made into the vertical type which exhaust gas flow flows upwards from the perpendicular direction downward, this invention is not limited to this, Even if it is a horizontal type in which exhaust gas flows in the horizontal direction, it can be applied as a method of suppressing self-excited vibration by shortening the length of the support interval at which the fin tube can freely vibrate.

1 Exhaust heat recovery boiler 2 Heat exchange vessel 3 Fin tube (heat transfer tube)
4 U-shaped tube 5 Circular tube 6 Fin 11 Perforated plate 12 Hole 13 Ceiling structural material 14 Suspension tool 15 Frame body hanging tool 16 Adhering material 20, 20 ′, 20 ”Support plate 20a Hole 20b Notch 22 Frame body 22a Horizontal portion 22b Portion 24 Connection plate 25 Pin 28 Diffusion prevention plate 30 Support beam

Claims (14)

A heat transfer tube group comprising a plurality of heat transfer tubes arranged orthogonal to the flow of exhaust gas;
A plurality of holes through which the heat transfer tubes are inserted are formed, and a plurality of perforated plates provided at predetermined intervals in the longitudinal direction of the heat transfer tube group;
A support plate disposed between the perforated plates and disposed to contact at least a portion of the heat transfer tube;
An exhaust heat recovery boiler comprising: The heat transfer tubes are arranged in a staggered manner in the vertical and horizontal directions,
The exhaust heat recovery boiler according to claim 1, wherein the support plate is provided so as to extend obliquely between adjacent heat transfer tubes with respect to a vertical direction.   The exhaust heat recovery boiler according to claim 1 or 2, further comprising a frame body to which both end portions of the support plate are fixed. The frame body has a rectangular shape connecting a horizontal portion and a vertical portion,
The exhaust heat recovery boiler according to claim 3, wherein the horizontal portion and the vertical portion are connected so as to be relatively movable. A drift prevention plate arranged on one side and the other side perpendicular to the longitudinal direction of the heat transfer tubes of the heat transfer tube group to prevent drift of the flow of the exhaust gas;
The exhaust heat recovery boiler according to claim 3 or 4, wherein the frame is fixed to the drift prevention plate.   The exhaust heat recovery boiler according to claim 5, wherein the support plate is in contact with the heat transfer tube from below in the vertical direction. Comprising a support beam extending horizontally to connect the upper ends of each of the perforated plates;
The exhaust heat recovery boiler according to claim 3 or 4, wherein the frame is supported by being suspended from the support beam.   The exhaust heat recovery boiler according to any one of claims 1 to 7, wherein an end portion in the width direction of the support plate is formed in an R shape having a roundness in a thickness direction.   The exhaust heat recovery boiler according to any one of claims 1 to 8, wherein the support plate has a plurality of holes or notches penetrating in the thickness direction.   The exhaust heat recovery boiler according to any one of claims 1 to 9, wherein the support plate has a wave shape in which peaks and valleys are alternately provided in a longitudinal direction.   The exhaust heat recovery boiler according to any one of claims 1 to 9, wherein the support plate has a shape with a convex central portion in the width direction.   The exhaust heat recovery boiler according to any one of claims 1 to 11, wherein the support plate is disposed at a center between the adjacent porous plates. The exhaust gas is denitrated with ammonia and contains sulfur oxides,
The exhaust heat recovery boiler according to any one of claims 1 to 12, wherein the support plate is provided in a region where the exhaust gas temperature is in a predetermined temperature range between 100C and 250C. Installing a heat transfer tube group consisting of a plurality of heat transfer tubes arranged orthogonal to the flow of exhaust gas;
Installing a plurality of perforated plates formed with a plurality of holes through which the heat transfer tubes are inserted with a predetermined interval in the longitudinal direction of the heat transfer tube group;
Installing a support plate between the perforated plates so as to contact the heat transfer tube;
The manufacturing method of the waste heat recovery boiler characterized by having.

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