WO2011093163A1

WO2011093163A1 - Waste heat boiler

Info

Publication number: WO2011093163A1
Application number: PCT/JP2011/050690
Authority: WO
Inventors: 昌計山田; 宏坪根; 満喜一石原
Original assignee: 三菱重工業株式会社
Priority date: 2010-01-26
Filing date: 2011-01-18
Publication date: 2011-08-04
Also published as: JP2013092260A

Abstract

Provided is a waste heat boiler which enables the prevention of the biased flow of process gas and a local temperature difference caused thereby, the prevention of the deformation and damage of a component disposed in a shell, and the reduction of cost by a simple structure. Specifically provided is a waste heat boiler (1) provided with: a cylindrically formed outer shell (2) which extends in a vertical direction; a water chamber (17) provided with a first chamber (19) to which water is supplied and a second chamber (20) into which heated water and water vapor flow; a plurality of heat transfer tubes (24); a plurality of plate-shaped members (31) which extend in the direction orthogonal to the plurality of heat transfer tubes (24) and are arranged along the vertical direction of the outer shell (2), and a bypass tube (37) which extends from the upper portion of the outer shell (2) to the lower portion of the outer shell (2) along the vertical direction of the outer shell (2) and through which the process gas that has flowed into the outer shell (2) is discharged.

Description

Waste heat boiler

The present invention relates to a waste heat boiler, and more particularly to a waste heat boiler that recovers waste heat from a chemical plant such as an ammonia plant and generates steam using the waste heat.

Conventionally, two types of waste heat boilers, a vertical water tube type and a horizontal smoke tube type, have been proposed as waste heat boilers that generate steam using waste heat (process gas) discharged from plant equipment.

FIG. 15 shows an example of a conventional vertical water tube waste heat boiler.
A conventional waste heat boiler 61 shown in FIG. 15 includes a cylindrical shell 62 extending in the vertical direction and a water chamber 63 provided on the upper portion of the shell 62.
Inside the shell 62, a tube bundle (tube bundle) 65 composed of a plurality of heat transfer tubes 64 and a plurality of baffle plates 66 extending in a direction orthogonal to the plurality of heat transfer tubes 64 are arranged.

As shown in FIG. 15, the shell 62 includes a cylindrical shroud 67 extending in the vertical direction and a fireproof heat insulating material 68 arranged so as to cover the periphery of the shroud 67. A gas inlet 69 is provided at the lower end of the shell 62. A process gas flows into the gas inlet 69 from a plant facility (not shown) via a gas pipe 70. On the other hand, a gas outlet 71 is provided in the upper part of the shell 62, and the process gas after flowing into the shell 62 and completing the heat exchange is discharged from the gas outlet 71.

As shown in FIG. 15, a bypass nozzle 72 is provided below the shell 62. The bypass nozzle 72 discharges the process gas flowing into the shell 62 in a high temperature state, and controls the temperature of the process gas discharged from the gas outlet 71 and supplied to the downstream equipment.
Further, the water chamber 63 disposed on the upper side of the tube plate 73 is divided into two rooms by a partition plate 74. The water chamber 63 includes a first chamber 76 into which water supplied from a steam drum (not shown) flows, and a second chamber 78 into which water and steam heated in the shell 62 flow. . The first chamber 76 is provided with a feed water inlet nozzle 75 connected to the steam drum, while the second chamber 78 is provided with a steam outlet nozzle 77 for discharging the mixed water and steam mixed phase fluid after heating. Is provided.

As shown in FIG. 15, each heat transfer tube 64 has one end 64 a connected to the first chamber 76 of the water chamber 63 and the other end 64 b connected to the second chamber 78 of the water chamber 63. Each of the heat transfer tubes 64 is formed in a U-shape, extends downward from the first chamber 76 of the water chamber 63, is folded at the lower portion of the shell 62, and other than the second chamber 78 of the water chamber 63. The connection is made at the end 64b.

As shown in FIG. 16, the plurality of baffle plates 66 includes a substantially rectangular first plate member 79 and a pair of second plate members 80 disposed so as to sandwich the first plate member 79. Has been. In the conventional example, as shown in FIG. 15, the first plate member 79 and the second plate member 80 are alternately arranged in parallel along the vertical direction of the shell 62. Further, each heat transfer tube 64 is disposed so as to pass through holes (not shown) provided in the plurality of baffle plates 66. As a support structure for the baffle plates 66, cylindrical spacers 81 and tie rods 82 are arranged at appropriate locations in the tube group of the heat transfer tubes 64 as shown in FIG. I am doing so.

Further, as shown in FIG. 16, skis 83 are attached to the outer circumferences of the plurality of baffle plates 66 so as to connect the baffle plates 66. The ski 83 has a function of facilitating insertion into a temporary cylinder (not shown) when transporting the tube bundle 65 and sliding the tube bundle 65 when inserting the tube bundle 65 into the shroud 67 to facilitate insertion. It comes to play a role.

As described above, in the conventional vertical water pipe waste heat boiler 61, the shroud 67 and the plurality of baffle plates 66 constitute a process gas flow path. The process gas rises while changing the flow direction along the flow path, and performs heat exchange with water in the heat transfer pipe 64. On the other hand, the water that has flowed into the first chamber 76 of the water chamber 63 flows through the heat transfer pipe 64 to exchange heat with the process gas, and becomes a mixed phase fluid of water and water vapor. This mixed phase of water and water vapor flows into the second chamber 78 of the water chamber 63 from the heat transfer tube 64 and is discharged from the steam outlet nozzle 77.

FIG. 18 shows an example of a conventional horizontal smoke tube waste heat boiler. FIG. 19 is an arrow view from the direction A in FIG.
The conventional waste heat boiler 91 of FIG. 18 includes an inlet gas chamber 92 into which process gas flows from a upstream device (not shown), an outlet gas chamber 93 into which process gas after heat exchange flows, and an inlet gas chamber 92. And an outlet gas chamber 93 are provided with a water chamber 94 extending in the horizontal direction.

As shown in FIG. 18, the inlet gas chamber 92 and the outlet gas chamber 93 are composed of a shroud 95 and a refractory heat insulating material 96 disposed so as to cover the periphery of the shroud 95. An inlet tube plate 97 is disposed between the inlet gas chamber 92 and the water chamber 94, and an outlet tube plate 98 is disposed between the outlet gas chamber 93 and the water chamber 94. In this conventional example, a plurality of heat transfer tubes 99 are arranged so as to pass through the water chamber 94, and one end 99a of each heat transfer tube 99 is connected to an inlet tube plate 97, and the other end 99b is an outlet tube. It is connected to the plate 98. Further, the bypass pipe 100 is disposed so as to pass through the center of the water chamber 94 in the axial direction. Similarly, the bypass pipe 100 has one end 100a connected to the inlet tube plate 97 and the other end 100b connected to the outlet pipe. It is connected to the plate 98.

As shown in FIG. 19, a steam drum 101 is provided above the water chamber 94. The steam drum 101 is provided with a downcomer (downcomer) 102, which extends along the outer periphery of the water chamber 94 and is connected to the lower portion of the water chamber 94. The steam drum 101 includes a riser (rising pipe) 103, and the riser 103 is connected to an upper nozzle 94 a provided at the upper part of the water chamber 64.

Further, as shown in FIG. 19, a pedestal 104 having a U-shaped cross section is provided below the water chamber 94. The water chamber 94 is supported by a support member 105 extending in the horizontal direction from the water chamber 94. Further, a shock absorber 106 is disposed between the support member 105 and the pedestal 104 in order to buffer the force in the vertical direction. The shock absorber 106 is composed of, for example, a spring. Thereby, even when the L-shaped connecting pipe 107 connected to the upstream device is thermally expanded in the arrow X direction (see FIG. 18), the vertical force applied to the support member 105 can be suppressed.
Furthermore, a sliding device 108 for sliding the support member 105 in the horizontal direction is disposed between the support member 105 and the pedestal 104. Thereby, even when the water chamber 94 is thermally expanded in the arrow Y direction (see FIG. 18), the horizontal force applied to the support member 105 can be released.

20 is an enlarged cross-sectional view of a portion B in FIG.
As shown in FIG. 20, the end 99 c of the heat transfer tube 99 is attached to the side surface 97 a of the inlet tube plate 97 on the water chamber side by strength welding 109. Further, a ferrule (joint pipe) 110 made of high alloy steel is inserted into the end portion 99c of the heat transfer pipe 99 through the shroud 95 and the refractory heat insulating material 96, whereby the heat transfer pipe 99 and the inlet gas are inserted. The chamber 92 is connected.

With the above configuration, in the conventional horizontal-type smoke tube waste heat boiler 91, as shown in FIG. 18, the process gas flowing into the inlet gas chamber 92 exchanges heat with water in the water chamber 94 through the heat transfer tube 99. The exhaust gas chamber 93 is discharged. On the other hand, as shown in FIG. 19, the water in the steam drum 101 flows into the water chamber 94 through the downcomer 102 and exchanges heat with the heat transfer pipe 99 to become a mixed phase fluid of water and water vapor. Thereafter, this mixed phase of water and water vapor returns to the steam drum 101 through the riser 103.

As another conventional example, Patent Document 1 discloses a waste heat recovery boiler device that cools combustion gas generated in a chemical plant or the like. The waste heat recovery boiler apparatus of Patent Document 1 includes a gas chamber to which combustion gas is supplied, a cooling chamber in which can water for cooling the combustion gas is stored, and a cooling chamber disposed in the cooling chamber. It consists of a heat transfer tube that is introduced to exchange heat with canned water.

JP 2004-92980 A

Hereinafter, problems of the conventional vertical water tube waste heat boiler 61 will be described with reference to the drawings.
In the waste heat boiler 61 of FIG. 15, when the operation starts, water flows in the heat transfer pipe 64, so that the temperature of the tube wall of the heat transfer pipe 64 does not rise so much. However, the spacer 81, the tie rod 82, and the ski 83 that directly contact the high temperature process gas become high temperature, and the temperature difference from the heat transfer tube 64 increases. As a result, the spacer 81, the tie rod 82, and the ski 83 extend downward due to heat, and push down the baffle plate 66.

On the other hand, when the baffle plate 66 comes into contact with the high-temperature process gas, the baffle plate 66 expands toward the outside of the shell 62, so that a compression surface pressure is generated between the hole provided in the baffle plate 66 and the heat transfer tube 64. As a result, the baffle plate 66 cannot move downward, and as shown in FIG. 17, the spacer 81, the tie rod 82, and the ski 83 are greatly buckled. At this time, these bucklings deform the baffle plate 66 and the shroud 67. Eventually, a gap is created between the baffle plate 66 and the shroud 67, and the amount of process gas passing through this gap increases. When the amount of the non-regular process gas increases at a high temperature passing through the gap as described above, a temperature difference is locally generated in the shroud 67, and the drift of the process gas flowing bypassing the bypass nozzle 72 is increased. Will be transformed.

Furthermore, as shown in FIG. 17, when the shroud 67 is deformed, the connecting portion between the shroud 67 and the bypass nozzle 72 is deformed, and as a result, a further gap is generated in this portion. When a gap is generated in the connecting portion between the shroud 67 and the bypass nozzle 72, a high-temperature process gas that does not flow in the tube bundle 65 directly bypasses between the shroud 67 and the refractory heat insulating material 68, thereby bypassing the bypass nozzle 72. Will flow into. As described above, when the bypass nozzle 72 is provided on the side surface of the shell 62, a high-temperature process gas drift and a bypass flow are generated, thereby causing a temperature difference in the shroud 67 and the like. As a result, the shroud 67 is deformed and damaged. Will be invited.

Further, since the ski 83 creeps in a buckled state, when the operation stops, the ski 83 contracts while maintaining the buckled shape, and the baffle plate 66 is pulled up. At this time, the welded portion between the baffle plate 66 and the ski 83 is broken, and the heat transfer tube 64 passing through the tube hole of the baffle plate 66 is in contact with the corner of the tube hole to damage the heat transfer tube 64. become.
Further, when the tube bundle 65 of the heat transfer tube 64 is pulled out from the shell 62 for maintenance, the shroud 67 and the baffle plate 66 are deformed and cannot be pulled out easily. Therefore, periodic maintenance is also affected.

Next, problems of the conventional horizontal smoke tube type waste heat boiler 91 will be described with reference to the drawings.
In the waste heat boiler 91 of FIG. 18, since the high-temperature process gas flows into the inlet gas chamber 92, the inlet tube plate 97 and the heat transfer tube 99 become high temperature. Therefore, the inlet tube plate 97 is covered with a refractory heat insulating material 96, and the strength weld 109 between the heat transfer tube 99 and the inlet tube plate 97 is disposed on the surface 97a of the inlet tube plate 97 on the water chamber 94 side in order to prevent damage. Yes. In addition, since the thickness of the inlet tube plate 97 cannot be increased in order to prevent the temperature of the gas side surface 97b (see FIG. 20) from increasing, the surface 97a of the inlet tube plate 97 on the water chamber 94 side is complicatedly reinforced. The structure was more complicated, such as requiring (not shown).
Further, if the process gas flows into the heat transfer tube 99 in a high temperature state, the heat transfer tube 99 and the tube plate 97 may be damaged by metal dusting or the like. Therefore, in the waste heat boiler 91, the ferrule 110 made of a high alloy has to be inserted into each heat transfer tube 99, which has also caused an increase in cost.

Further, as a countermeasure when the connecting pipe 107 is thermally expanded in the arrow X direction (see FIG. 18), the force in the vertical direction is buffered between the support member 105 and the pedestal 104 as shown in FIG. It was necessary to arrange a shock absorber 106 for the purpose. In addition, in the waste heat boiler 91, the structure in which the water chamber 94 and the steam drum 101 are connected by the downcomer 102 and the riser 103 and the steam drum 101 is supported by the several risers 103 also complicates the structure and reduces the cost. Was the cause of the increase.

The present invention has been made in view of such circumstances, and its purpose is to prevent process gas drift and local temperature differences resulting therefrom, as well as deformation and damage of parts disposed in the shell. Is to provide a waste heat boiler that can reduce costs with a simple structure.

In order to solve the above-described problems of the prior art, according to an embodiment of the present invention, a waste heat boiler that generates water vapor using waste heat discharged from plant equipment, and has a cylindrical shape extending in the vertical direction. An outer shell formed so that process gas discharged from the plant equipment flows into the lower end, a first chamber provided at the upper portion of the outer shell and supplied with water, and after heating A water chamber having a second chamber into which water and water vapor flow in, and extending downward from the first chamber of the water chamber, folded back at a lower portion of the outer shell, and the second of the water chamber. A plurality of heat transfer tubes connected to the chamber, a plurality of plate-like members extending in a direction orthogonal to the plurality of heat transfer tubes and arranged in parallel along the vertical direction of the outer shell, Extends from the upper part of the outer shell to the lower part of the outer shell along the vertical direction of the shell Both waste heat boiler and a bypass pipe for discharging the process gas that has flowed into the outer shell is provided.

Further, according to another embodiment of the present invention, the bypass pipe penetrates the water chamber and extends through the axial center of the outer shell to the lower portion of the outer shell.

Moreover, according to another embodiment of the present invention, it has an inner tube and an outer tube extending downward from the water chamber, the outer tube is connected to the first chamber of the water chamber and the inner tube Comprises a plurality of double tubes connected to the second chamber of the water chamber, and each heat transfer tube is disposed so as to pass through holes provided in the plurality of plate-like members, A double tube passes through holes provided in the plurality of plate-like members and supports the plurality of plate-like members.

According to another embodiment of the present invention, the second chamber of the water chamber is provided with a first screw hole at a connection portion between the double tube and the inner tube, A cylindrical first tube holding member having a thread groove formed on the outer peripheral surface thereof is screwed into the screw hole, and the terminal portion of the inner tube of the double tube is connected to the first tube holding member. And is attached to the second chamber.

According to another embodiment of the present invention, a step portion is formed at a position on the outer shell side on the inner peripheral surface of the first tube holding member, and the double tube is formed on the step portion. The end portion of the inner tube is fitted, and the first tube holding member presses the end portion of the inner tube of the double tube with the stepped portion, while the first chamber of the second chamber is The screw hole is configured to be screwed.

According to another embodiment of the present invention, the second chamber of the water chamber is provided with a second screw hole at the position of the heat transfer tube, and the second screw hole has an outer periphery. A cylindrical second tube holding member having a thread groove formed on the surface is screwed together, a ferrule is inserted into the heat transfer tube, and a ferrule end portion inserted into the heat transfer tube is It is attached to the second chamber via the second tube holding member.

According to another embodiment of the present invention, a stepped portion is formed at a position on the outer shell side on the inner peripheral surface of the second tube holding member, and the end of the ferrule is formed on the stepped portion. And the second tube holding member is configured to be screwed into the second screw hole of the second chamber while pressing the end portion of the ferrule with the stepped portion. Yes.

According to another embodiment of the present invention, a plurality of rod-shaped members that extend in the vertical direction of the outer shell and support the plate-shaped member disposed on the upper portion of the outer shell, A spacer disposed around the rod-shaped member and configured to maintain a space between the plate-shaped members, and the hole of the plate-shaped member disposed at the lower portion of the outer shell has a first screw portion. Each of the double pipes is formed with a second screw part at a position corresponding to the first screw part, and the first screw part of the plate-like member and the second screw part of the double pipe are formed. When the two screw portions are screwed together, the plate-like member disposed at the lower portion of the outer shell is supported.

According to another embodiment of the present invention, a cylindrical member is disposed around the outer tube at a connection portion between the outer tube of the double tube and the first chamber of the water chamber. The outer diameter of the cylindrical member is larger than the outer diameter of the portion of the double pipe provided with the second threaded portion.

According to the waste heat boiler according to the present invention, an outer shell that is formed in a cylindrical shape extending in the vertical direction and configured so that process gas discharged from the plant equipment flows into a lower end portion, and an upper portion of the outer shell. A water chamber comprising a first chamber to which water is supplied, a second chamber into which heated water and water vapor flows, and extends downward from the first chamber of the water chamber. A plurality of heat transfer tubes that are folded back at a lower portion of the outer shell and connected to the second chamber of the water chamber, and extend in a direction orthogonal to the plurality of heat transfer tubes, A plurality of plate-like members arranged in parallel in the vertical direction, and the process gas that extends from the upper part of the outer shell to the lower part of the outer shell along the vertical direction of the outer shell and flows into the outer shell And a bypass pipe that discharges Is harvested by bypass pipe in the lower part of the shell can be discharged from the top of the shell.
Conventionally, a drift that causes a high-temperature process gas to flow toward the side surface of the outer shell has occurred. However, according to the present invention, the drift of the process gas is prevented and a temperature difference caused locally due to this is prevented. Can also prevent. Thereby, it is possible to prevent deformation of components in the shell, for example, baffle plates (plate-like members), inner cylinders, and the like.

Further, according to the waste heat boiler according to the present invention, the bypass pipe extends through the water chamber and passes through the axial center of the outer shell to the lower portion of the outer shell. The process gas flowing into the shell is collected axisymmetrically around the bypass pipe and discharged from the upper part of the outer shell. Thereby, the drift of process gas can be prevented more effectively, and the temperature difference which arises locally by this can also be prevented.

The waste heat boiler according to the present invention further includes an inner pipe and an outer pipe extending downward from the water chamber, the outer pipe being connected to the first chamber of the water chamber and the inner pipe. Comprises a plurality of double tubes connected to the second chamber of the water chamber, and each heat transfer tube is disposed so as to pass through holes provided in the plurality of plate-like members, A double tube passes through holes provided in the plurality of plate-like members and supports the plurality of plate-like members.
Conventionally, the plate-like member is supported by the tie rod and the spacer. However, according to the present invention, the plate-like member is supported only by the double pipe, so when the waste heat boiler is operated, the double pipe is used. And a heat exchanger tube and a plate-shaped member will move similarly to an up-down direction, and can prevent a deformation | transformation and damage of a plate-shaped member.

Further, according to the waste heat boiler according to the present invention, a step portion is formed at a position on the outer shell side on the inner peripheral surface of the first tube holding member, and the double pipe is formed on the step portion. The end portion of the inner tube is fitted, and the first tube holding member presses the end portion of the inner tube of the double tube with the stepped portion, while the first chamber of the second chamber is The inner pipe of the double pipe is securely held by the first pipe holding member and the non-rotating nut so that the waste heat boiler can be operated for a long time. The structure is not loosened.

Further, according to the waste heat boiler according to the present invention, a stepped portion is formed at a position on the outer shell side on the inner peripheral surface of the second tube holding member, and the stepped portion is formed on the heat transfer tube. The end portion of the inserted ferrule is fitted, and the second tube holding member is screwed into the second screw hole of the second chamber while pressing the end portion of the ferrule with the stepped portion. Further, since the rotation is stopped by the rotation stop nut, the ferrule is securely held by the second tube holding member, and the structure is such that it does not loosen even during long-time operation of the waste heat boiler.

Further, according to the waste heat boiler according to the present invention, the plurality of rod-shaped members that extend along the vertical direction of the outer shell and support the plate-shaped member disposed on the upper portion of the outer shell, A spacer disposed around the rod-shaped member and configured to maintain a space between the plate-shaped members, and the hole of the plate-shaped member disposed at the lower portion of the outer shell has a first screw portion. Each of the double pipes is formed with a second screw part at a position corresponding to the first screw part, and the first screw part of the plate-like member and the second screw part of the double pipe are formed. Since the plate-like member arranged at the lower part of the outer shell is supported by being screwed with the screw part 2, the plate-like member arranged at the upper part of the outer shell is supported by the rod-like member The plate-like member disposed at the lower part of the outer shell is supported by the double pipe. .
Conventionally, the lower plate member of the outer shell was supported by a rod member (tie rod) and a spacer, but according to the present invention, the lower plate member of the outer shell is not a rod member or a spacer, Supported only by double tubes. Therefore, problems such as buckling of the rod-shaped member and the spacer due to the high-temperature process gas do not occur in the lower part of the outer shell. Moreover, since the rod-shaped member and the spacer are not arranged in the lower part of the outer shell, when the waste heat boiler is operated, the double tube, the heat transfer tube, and the plate-like member move in the same manner in the vertical direction. Also, deformation and damage of the plate-like member can be prevented.
On the other hand, since the temperature of the process gas is low at the upper part of the outer shell, even if the plate member is supported by the rod member and the spacer, the rod member and the spacer do not buckle.

Further, according to the waste heat boiler according to the present invention, a cylindrical member is disposed around the outer pipe at a connection portion between the outer pipe of the double pipe and the first chamber of the water chamber. The outer diameter of the cylindrical member is larger than the outer diameter of the portion of the double pipe provided with the second threaded portion. According to this configuration, by removing the cylindrical member first at the connection portion between the outer tube of the double tube and the first chamber of the water chamber, a space for passing the outer tube of the double tube through the connection portion is provided. Can be made. Therefore, even when the outer pipe of the double pipe leaks, the double pipe can be pulled up to the water chamber above the outer shell, and the double pipe can be removed.

It is a sectional view of the whole waste heat boiler concerning a 1st embodiment. FIG. 2 is a cross-sectional view taken along line AA in FIG. FIG. 3 is a sectional view taken along line BB in FIG. It is sectional drawing which showed the support structure of the double pipe which concerns on 1st Embodiment. It is sectional drawing which showed the support structure of the heat exchanger tube which concerns on 1st Embodiment. It is sectional drawing to which the part of C in FIG. 5 was expanded. It is the figure which showed the installation level of the waste heat boiler which concerns on 1st Embodiment, and the upstream apparatus arrange | positioned upstream of a waste heat boiler. It is sectional drawing of the whole waste heat boiler which concerns on 2nd Embodiment. It is sectional drawing which showed the double pipe and tie rod which concern on 2nd Embodiment. It is sectional drawing to which the 2nd thread part of the outer tube of the double tube which concerns on 2nd Embodiment was expanded, and is the figure which showed the outer tube formed by the vacuum diffusion welding method. It is sectional drawing to which the 2nd thread part of the outer tube of the double tube which concerns on 2nd Embodiment was expanded, and is the figure which showed the outer tube formed by the extrusion molding method. It is sectional drawing to which the part of D in FIG. 9 was expanded. It is sectional drawing of the whole waste heat boiler which concerns on 2nd Embodiment, and is the figure which showed the process of taking out the leaked double pipe. It is sectional drawing to which the D section in Drawing 9 was expanded, and is a figure showing the composition after removing a double pipe. It is sectional drawing of the whole conventional vertical water pipe | tube type waste heat boiler. FIG. 16 is a cross-sectional view taken along line AA in FIG. It is the figure which showed the state after driving | running the conventional vertical water pipe | tube-type waste heat boiler, and is the figure which showed the components in the shell deform | transformed by the drift of the process gas. It is sectional drawing of the whole conventional horizontal-type smoke pipe type waste heat boiler. It is an arrow view from the A direction of FIG. It is sectional drawing which expanded the part of B in FIG.

[First Embodiment]
Hereinafter, a waste heat boiler according to a first embodiment of the present invention will be described with reference to the drawings. FIG. 1 is an overall cross-sectional view of a waste heat boiler according to the present embodiment. 2 is a cross-sectional view taken along the line AA in FIG. 1, and FIG. 3 is a cross-sectional view taken along the line BB in FIG.

The waste heat boiler 1 according to the present embodiment generates steam by using waste heat discharged from plant equipment. In this embodiment, waste heat discharged from a chemical plant such as an ammonia plant is used as an example of plant equipment.

As shown in FIG. 1, the waste heat boiler 1 includes a shell (outer shell) 2 formed in a cylindrical shape extending in the vertical direction. The shell 2 includes a cylindrical shroud 3 extending in the vertical direction and a refractory heat insulating material 4 arranged so as to cover the periphery of the shroud 3. A flange portion 2 a extending outward in the circumferential direction is provided at the upper end portion of the shell 2, and the flange portion 2 a is fixed to a tube plate 5 provided above the shell 2 by bolts 6. ing.

Also, a cylindrical inner cylinder 7 extending in the vertical direction is disposed inside the shroud 3. A flange portion 7 a extending toward the outer side in the circumferential direction is provided at the upper end portion of the inner cylinder 7, and the flange portion 7 a is fixed to the tube plate 5 with bolts 8.

As shown in FIG. 1, a gas inlet 9 is provided at the lower end of the shell 2. The gas inlet 9 is connected to the upstream device 54 (see FIG. 7) via the gas pipe 10, so that the high-temperature process gas discharged from the upstream device 54 flows into the gas inlet 9. It has become. Further, a refractory brick 11 is laid around the gas inlet 9, and the refractory brick 11 rectifies the flow of the process gas flowing from the gas inlet 9.

As shown in FIG. 1, a gas collecting chamber 12 is provided in the upper part of the shell 2 along the circumferential direction of the shell 2. The gas collecting chamber 12 is connected to a gas outlet nozzle 13 provided in the horizontal direction at the top of the shell 2. Here, the gas collecting chamber 12 and the gas outlet nozzle 13 are joined by an expansion joint 14.
As shown in FIG. 2, the gas collecting chamber 12 includes an inner cylinder 7 disposed inside the shell 2 and an outer diameter portion 15 provided along the outer diameter of the shell 2. The inner cylinder 7 is provided with a gas through hole 16 at a position corresponding to the gas collecting chamber 12, and the process gas flowing into the shell 2 enters the gas collecting chamber 12 through the gas through hole 16, and then It flows from the gas collecting chamber 12 to the gas outlet nozzle 13.

As shown in FIG. 1, a water chamber 17 is provided on the upper side of the tube plate 5. The water chamber 17 is divided into two upper and lower rooms by a partition plate 18 extending in the horizontal direction. The water chamber 17 includes a first chamber 19 provided below the partition plate 18 and a second chamber 20 provided above the partition plate 18. A water supply inlet nozzle 21 is provided in the first chamber 19 so that water supplied from a steam drum (not shown) flows in. On the other hand, a steam outlet nozzle 22 is provided in the second chamber 20, and water and steam heated in the shell 2 are discharged from the steam outlet nozzle 22. The second chamber 20 is provided with a manhole 23 for the purpose of internal inspection.

As shown in FIG. 1, the waste heat boiler 1 further includes a plurality of heat transfer tubes 24. The plurality of heat transfer tubes 24 bundles several heat transfer tubes 24 as one tube bundle (tube bundle). In the present embodiment, the plurality of heat transfer tubes 24 are divided into three tube groups of a first tube bundle 24A, a second tube bundle 24B, and a third tube bundle (not shown).
As shown in FIG. 1, each heat transfer tube 24 has both ends 25 connected to the first chamber 19 of the water chamber 17. Each heat transfer tube 24 is formed in a U shape, extends downward from the first chamber 19 of the water chamber 17, is folded at the lower portion of the shell 2, and is connected to the first chamber 19 of the water chamber 17. is doing. As shown in FIG. 6, a ferrule 50 is inserted into one end 25 of the heat transfer tube 24, and the upper end of the ferrule 50 is connected to the second chamber 20 of the water chamber 17.

Furthermore, as shown in FIG. 1, the waste heat boiler 1 includes a plurality of double tubes (bionette heat transfer tubes) 27. As shown in FIG. 4, each double pipe 27 has an outer pipe 28 and an inner pipe 29 that extend downward from the water chamber 17. The outer tube 28 is connected to the first chamber 19 of the water chamber 17, and the inner tube 29 is connected to the second chamber 20 of the water chamber 17.
In the present embodiment, the double tube 27 is mixed in the heat

transfer tube bundles

24A and 24B described above, and the heat transfer tube 24 and the double tube 27 constitute one

tube bundle

24A and 24B. In the present embodiment, a plurality of dummy pipes 30 are also arranged in the first tube bundle 24A. The dummy pipe 30 is disposed under the first tube bundle 24A and serves to rectify the process gas flowing into the shell 2.

As shown in FIG. 1, the waste heat boiler 1 includes a plurality of baffle plates (plate members) 31 extending in a direction orthogonal to the plurality of heat transfer tubes 24 and the double tubes 27.
As shown in FIG. 3, the plurality of baffle plates 31 includes a first plate member 32 formed in a circular shape and a second plate member 33 formed concentrically with the first plate member 32 and formed in a donut shape. Has been. In the present embodiment, as shown in FIG. 1, the first plate material 32 and the second plate material 33 are alternately arranged in parallel along the vertical direction of the shell 2.

In the present embodiment, each heat transfer tube 24 is disposed so as to pass through holes (not shown) provided in the first and

second plate members

32 and 33. As shown in FIG. 3, each double tube 27 penetrates through a hole 34 provided in the first and

second plate members

32 and 33 and supports the first and

second plate members

32 and 33. ing. That is, in the present embodiment, a plurality of baffle plates 31 are supported not by the U-shaped heat transfer tube 24 but by the double tube 27.
As shown in FIG. 4, the support structure of the baffle plate 31 includes a cylindrical spacer 35 disposed around the double pipe 27 in the upper part of the shell 2, and the gap between the tube plate 5 and the baffle plate 31. It is designed to hold the interval. In the lower part of the shell 2, the baffle plate 31 is attached to the double pipe 27 via a stopper 36.

In the present embodiment, as shown in FIG. 1, the waste heat boiler 1 includes a bypass pipe 37 that extends along the vertical direction of the shell 2 and discharges the process gas flowing into the shell 2. . The bypass pipe 37 extends from a bypass nozzle 38 provided in the upper part of the water chamber 17, passes through the first and

second chambers

19 and 20 of the water chamber 17, and further passes through the tube plate 5 to pass through the shell 2. It extends to the bottom of the. Further, as shown in FIG. 3, the bypass pipe 37 extends to the lower part of the shell 2 through the center in the axial direction of the shell 2, and collects and discharges the high-temperature process gas in an axisymmetric manner. It has become.

Further, as shown in FIG. 1, the bypass nozzle 38 is provided with a process gas damper 39. The process gas damper 39 is a ball valve, and includes a ball-shaped valve body 40 and a valve chamber 41 in which the valve body 40 is disposed. The valve body 40 is provided with a through hole (not shown), and the valve body 40 rotates in the valve chamber 41 to open and close the flow path of the bypass pipe 37.

Next, the mounting structure of the double tube 27 and the heat transfer tube 24 will be described in detail with reference to the drawings. FIG. 4 is a cross-sectional view showing a double tube support structure according to the present embodiment, and FIG. 5 is a cross-sectional view showing a heat transfer tube support structure according to the present embodiment. FIG. 6 is an enlarged cross-sectional view of a portion C in FIG.

As shown in FIG. 4, the upper surface 5 a of the tube plate 5 is overlaid with a high alloy containing nickel or the like, and the end portion 28 a of the outer tube 28 of the double tube 27 is attached to the overlay portion 42 by strength welding 43. It has been. On the other hand, the inner pipe 29 of the double pipe 27 is attached to the partition plate 18 of the water chamber 17 via the first pipe holding member 44. The partition plate 18 of the water chamber 17 is provided with a first screw hole 45 at a position corresponding to the inner tube 29 of the double tube 27. Here, the first screw hole 45 is formed by a female screw. The first tube holding member 44 is a cylindrical member, and a thread groove 46 is formed on the outer peripheral surface of the first tube holding member 44. Here, the screw groove 46 is formed by a male screw, and the outer peripheral surface of the first tube holding member 44 is screwed into the first screw hole 45.

As shown in FIG. 4, the first tube holding member 44 has two holes with different inner diameters, and a step 47 is formed at a position on the shell 2 side of the first tube holding member 44. Has been. The end portion 29 a of the inner tube 29 of the double tube 27 is fitted to the stepped portion 47, and the first tube holding member 44 connects the end portion 29 a of the inner tube 29 of the double tube 27 to the stepped portion 47. The first screw hole 45 of the partitioning plate 18 is screwed into the separator plate 18 while being pressed.

Further, a gap 48 is provided between the inner peripheral surface of the first tube holding member 44 and the outer peripheral surface of the inner tube 29 of the double tube 27. The gap 48 functions as an adjustment portion when there is a manufacturing error. For example, even if there is a manufacturing error in the pitch of the inner tube 29 of the double tube 27, the end portion 29a of the inner tube 29 is fitted to the stepped portion 47 of the first tube holding member 44.
Further, a locking nut 49 is screwed into the first tube holding member 44 from the partition plate 18 side. As a result, the first tube holding member 44 is configured not to loosen even when there is vibration or the like.

As shown in FIG. 6, both ends 25 of the heat transfer tube 24 connected to the first chamber 19 of the water chamber 17 are attached to the overlay portion 42 on the tube plate 5 by strength welding 43 as described above. .
One end of the heat transfer tube 24 is connected to the first chamber 19, while the other end of the heat transfer tube 24 is connected to the second chamber 20 via a ferrule (joint tube) 50 as shown in FIG. It is connected. As shown in FIG. 6, the end portion 25 of the heat transfer tube 24 is attached to the overlay portion 42 on the tube sheet 5 by strength welding 43. Further, the outer diameter of the end portion 50 a on the heat transfer tube side of the ferrule 50 is formed to a size corresponding to the inner diameter of the end portion 25 of the heat transfer tube 24, and the end portion 50 a of the ferrule 50 is the end portion of the heat transfer tube 24. It is attached so as to be inserted into the portion 25.

Further, as shown in FIG. 5, the end portion 50 b of the ferrule 50 on the side of the partition plate 18 is attached to the partition plate 18 of the water chamber 17 via the second tube holding member 51. The partition plate 18 of the water chamber 17 is provided with a second screw hole 52 at a position corresponding to the ferrule 50. Here, the second screw hole 52 is formed by a female screw. The second tube holding member 51 is a cylindrical member, and a screw groove 53 is formed on the outer peripheral surface of the second tube holding member 51. Here, the screw groove 53 is formed of a male screw, and the outer peripheral surface of the second tube holding member 51 is screwed into the second screw hole 52. In addition, about the other structure of the 2nd pipe | tube holding member 51, since it is the same structure as the 1st pipe | tube holding member 44 mentioned above, description is abbreviate | omitted.

Next, the relationship between the waste heat boiler 1 according to the present embodiment and the upstream apparatus disposed on the upstream side of the waste heat boiler will be described. FIG. 7 is a diagram showing the installation level of the waste heat boiler according to the present embodiment and the upstream apparatus disposed on the upstream side of the waste heat boiler.

As shown in FIG. 7, the installation level 55 is the same between the waste heat boiler 1 and the upstream apparatus 54 that supplies the process gas. In the present embodiment, since the waste heat boiler 1 and the upstream device 54 are similarly heated in the vertical direction, if the installation level 55 is the same, a shock absorber as in the prior art is not necessary.

Next, the flow of process gas and water in the waste heat boiler 1 according to this embodiment will be described with reference to the drawings.

As shown in FIG. 1, the process gas is supplied from the upstream device 54 (see FIG. 7) to the gas inlet 9 through the gas pipe 10. Thereafter, the process gas flowing in from the gas inlet 9 is rectified by the refractory brick 11, and then rises while meandering the flow path formed by the inner cylinder 7 and the baffle plate 31.
In the lower part of the shell 2, the high-temperature process gas is collected in an axisymmetric manner in the bypass pipe 37 and is discharged to the outside of the shell 2 by the bypass pipe 37. On the other hand, the process gas that has not flowed into the bypass pipe 37 exchanges heat with water in the outer pipe 28 (see FIG. 4) of the heat transfer pipe 24 and the double pipe 27 while rising in the shell 2.
Then, as shown in FIG. 2, the process gas after the heat exchange enters the gas collecting chamber 12 through the gas through hole 16 at the upper portion of the shell 2, and then the gas outlet nozzle from the gas collecting chamber 12. It flows to 13.

As shown in FIG. 1, the water supplied from the steam drum to the water chamber 17 flows into the heat transfer tube 24 and the double tube 27 through the first chamber 19.
In the heat transfer tube 24, the inflowing water exchanges heat with the process gas to become a mixed phase of water and water vapor, and flows into the second chamber 20 of the water chamber 17.
On the other hand, in the double pipe 27, the inflowing water exchanges heat with the process gas while passing through the outer pipe 28 to become a mixed phase of water and water vapor. Thereafter, a mixed phase fluid of water and water vapor flows into the second chamber 20 of the water chamber 17 through the inner pipe 29. Finally, the mixed phase fluid of water and steam flowing into the second chamber 20 is discharged from the steam outlet nozzle 22.

As described above, according to the waste heat boiler 1 according to the present embodiment, the shell 2 is formed in a cylindrical shape extending in the vertical direction, and is configured so that the process gas discharged from the upstream device 54 flows into the lower end portion. A water chamber 17 provided in the upper part of the shell 2 and provided with a first chamber 19 to which water is supplied and a second chamber 20 into which water and water vapor after heating flow, and a first of the water chamber 17. A plurality of heat transfer tubes 24 extending downward from the chamber 19, folded back at the bottom of the shell 2 and connected to the second chamber 20 of the water chamber 17 via the ferrule 50, and the plurality of heat transfer tubes 24 A plurality of baffle plates 31 that extend in a direction perpendicular to each other and are arranged in parallel along the vertical direction of the shell 2, pass through the water chamber 17, and extend to the lower portion of the shell 2 through the axial center of the shell 2. The inside of the shell 2. Inflowing process gas, the central axis symmetrically gathered in the bypass pipe 37 and is discharged from the top of the shell 2.
Conventionally, a drift has occurred in which a high-temperature process gas flows toward the side surface of the shell. However, according to the present invention, the process gas is prevented from drifting, and a temperature difference caused locally is also caused. Can be prevented. Thereby, it can prevent that the components in the shell 2, for example, a baffle plate (plate-shaped member) 31, the shroud 3, the inner cylinder 7, etc., are deformed.

According to the waste heat boiler 1 according to the present embodiment, the plurality of baffle plates 31 include a first plate member 32 formed in a circular shape and a second plate formed in a donut shape concentrically with the first plate member 32. Since the plate material 33 is used, the process gas flowing in the shell 2 can flow axisymmetrically around the bypass pipe 37. Thereby, the drift of process gas can be prevented effectively.

Moreover, according to the waste heat boiler 1 which concerns on this embodiment, while having the inner tube | pipe 29 and the outer tube | pipe 28 which extend below from the water chamber 17, the outer tube | pipe 28 is connected to the 1st chamber 19 of the water chamber 17, and The inner tube 29 includes a plurality of double tubes 27 connected to the second chamber 20 of the water chamber 17, and each heat transfer tube 24 is disposed so as to penetrate through holes provided in the plurality of baffle plates 31. Each double tube 27 passes through holes 34 provided in the plurality of baffle plates 31 and supports the plurality of baffle plates 31.
Conventionally, since the baffle plate is supported by the tie rod 82 and the spacer 81 (see FIG. 15), there is a problem that the tie rod and the spacer are buckled by a high-temperature process gas. Since the baffle plate 31 is supported only by 27, when the waste heat boiler 1 is operated, the double tube 27 and the heat transfer tube 24 move in the same manner as the baffle plate 31 in the vertical direction. The deformation and damage of 31 can be prevented.
In the present embodiment, unlike the conventional case, no spacers or tie rods are used in the lower part of the shell 2, so that problems such as deformation of the spacers and tie rods due to high-temperature process gas do not occur.

Moreover, according to the waste heat boiler 1 which concerns on this embodiment, the 1st screw hole 45 is provided in the connection part with the inner tube | pipe 29 of the double pipe 27 in the partition plate 18 of the water chamber 17, and 1st A cylindrical first tube holding member 44 having a screw groove 46 formed on the outer peripheral surface is screwed into the screw hole 45, and a stepped portion 47 is formed on the inner peripheral surface of the first tube holding member 44. The end portion 29a of the inner tube 29 of the double tube 27 is fitted to the step portion 47, and the first tube holding member 44 connects the end portion 29a of the inner tube 29 of the double tube 27 to the step portion 47. It is configured to be screwed into the first screw hole 45 of the partition plate 18 while being pressed.
Therefore, in the past, for example, the inner pipe was attached to the partition plate by welding, but according to the present invention, the first pipe holding member 44 is configured to be removable, so that the maintenance of the double pipe 27 is performed. Sometimes the inner tube 29 or the like can be easily removed.
Moreover, according to the waste heat boiler 1 which concerns on this embodiment, the inner pipe | tube 29 of the double pipe 27 will be reliably hold | maintained with the 1st pipe | tube holding member 44, and in the long-time driving | operation of the waste heat boiler 1. The structure is not loosened. In particular, since the locking nut 49 is screwed into the first tube holding member 44 from the partition plate 18 side, the first tube holding member 44 is not loosened even when there is vibration. It has become.

Moreover, according to the waste heat boiler 1 which concerns on this embodiment, the 2nd screw hole 52 is provided in the connection part with the ferrule 50 in the partition plate 18 of the water chamber 17, and in the 2nd screw hole 52, A cylindrical second tube holding member 51 having a thread groove 53 formed on the outer peripheral surface is screwed together. A stepped portion 47 is formed on the inner peripheral surface of the second tube holding member 51. The end portion 50b of the ferrule 50 is fitted, and the second tube holding member 51 is screwed into the second screw hole 52 of the partition plate 18 while pressing the end portion 50b of the ferrule 50 with the stepped portion 47. It is configured as follows.
According to the present invention, since the second tube holding member 51 is configured to be removable, the ferrule 50 can be easily taken out during maintenance of the heat transfer tube 24.
Moreover, according to the waste heat boiler 1 which concerns on this embodiment, the ferrule 50 connected to the heat exchanger tube 24 is reliably hold | maintained by the 2nd tube holding member 51, and the non-rotating nut 49 is screwed together. The structure is such that the waste heat boiler 1 does not loosen even during long-time operation.

Further, according to the waste heat boiler 1 according to the present embodiment, the plurality of heat transfer tubes 24 are divided into three tube groups of the first tube bundle 24A, the second tube bundle 24B, and the third tube bundle. The U-shaped maximum bending radius of the heat transfer tube 24 can be reduced. Thereby, the vibration of the U-shaped portion of the heat transfer tube 24 due to the flow of the process gas can be prevented without attaching a special vibration-proofing fitting or the like. Moreover, this structure can respond also to the enlargement of the waste heat boiler 1. FIG.

Further, according to the waste heat boiler 1 according to the present embodiment, the gap 48 is provided between the inner peripheral surface of the first tube holding member 44 and the outer peripheral surface of the inner tube 29 of the double tube 27. Therefore, for example, even when there is a manufacturing error in the inner tube 29 of the double tube 27 or the pitch of the ferrule 50, the end portion 29 a of the inner tube 29 is fitted into the stepped portion 47 of the first tube holding member 44. be able to.

Further, according to the waste heat boiler 1 according to the present embodiment, the installation level 55 is the same between the waste heat boiler 1 and the upstream apparatus 54 that supplies process gas. In the present embodiment, since the waste heat boiler 1 and the upstream apparatus 54 are similarly heated in the vertical direction, if the installation level 55 is the same, a shock absorber as in the prior art is not necessary and simple. The cost can be reduced with a simple structure.

[Second Embodiment]
Hereinafter, the waste heat boiler which concerns on 2nd Embodiment of this invention is demonstrated, referring drawings. FIG. 8 is an overall cross-sectional view of the waste heat boiler according to the present embodiment. FIG. 9 is a view showing a double tube and a tie rod according to the present embodiment. In addition, about the part similar to what was demonstrated by embodiment mentioned above, the same code | symbol is attached | subjected and the overlapping description is abbreviate | omitted.

In the second embodiment, unlike the first embodiment, the support structure of the baffle plate 31 is different between the upper part and the lower part of the shell 2.
As shown in FIG. 8, the waste heat boiler 201 of this embodiment is arranged around a plurality of tie rods (bar-shaped members) 202 extending along the vertical direction of the shell 2 and the tie rods 202, And a spacer 203 for maintaining a gap therebetween. As shown in FIG. 8, the tie rod 202 and the spacer 203 are disposed only on the upper portion of the shell 2 and support the baffle plate 31 disposed on the upper portion of the shell 2.

As shown in FIG. 9, the tie rod 202 includes a main body portion 204 having a thread groove formed on the outer peripheral surface of the lower end portion 204b, and an insertion portion 205 having a screw groove formed on the outer peripheral surface of the upper end portion. . The body portion 204 of the tie rod 202 is disposed so as to penetrate the hole 31 a provided in the baffle plate 31. The insertion portion 205 of the tie rod 202 is screwed into a screw groove 5 b provided in the tube plate 5. On the other hand, a nut 206 is screwed into the lower end portion 204 b of the main body portion 204 of the tie rod 202.

As shown in FIG. 9, the spacer 203 is formed in a cylindrical shape and is disposed around the main body portion 204 of the tie rod 202. The tie rod 202 is disposed between the two baffle plates 31 disposed above and below, and maintains a distance between the baffle plates 31.

As shown in FIG. 8, in the present embodiment, the tie rod 202 and the spacer 203 are disposed at approximately the upper half position in the shell 2. However, the present invention is not limited to this arrangement, and the arrangement positions of the tie rod 202 and the spacer 203 can be changed.
Inside the shell 2, the temperature is higher in the lower part where the process gas flows. In view of this, the tie rod 202 and the spacer 203 can be extended from the position of the tube plate 5 to a temperature at which the tie rod 202 and the spacer 203 are not buckled.

Next, the support structure of the baffle plate 31 in the lower part of the shell 2 will be described.
As shown in FIG. 9, a first screw portion 207 is formed in the hole 34 of the baffle plate 31 arranged at the lower part of the shell 2. The first screw portion 207 is a female screw. Further, a second screw portion 208 is formed in the outer tube 28 of the double tube 27 at a position corresponding to the first screw portion 207. The second screw portion 208 is a male screw and is screwed with the first screw portion 207. Therefore, the first screw portion 207 of the baffle plate 31 and the second screw portion 208 of the outer tube 28 of the double tube 27 are screwed together, so that the baffle plate 31 disposed at the lower portion of the shell 2 is supported. It has become so.

As a method for forming the second threaded portion 208 of the outer tube 28, there is a vacuum diffusion welding method. The vacuum diffusion welding method is a method in which a base material is brought into close contact, pressure is applied under a temperature condition equal to or lower than the melting point of the base material, and joining is performed using diffusion of atoms generated on a joint surface. In this method, the welding atmosphere is performed under vacuum. As shown in FIG. 10, when this method is used, a base material for welding is separately welded to the outer periphery of the outer tube 28 of the double tube 27, and then a screw is cut to the base material to form a second screw. A portion 208 is formed.

Further, as another method for forming the second screw portion 208 of the outer tube 28, there is an extrusion molding method. The extrusion molding method is a method of forming a cross section of a pipe by extruding a raw material from a mold. When this method is used, a groove is previously formed in a mold for forming the outer tube 28 of the double tube 27, and the second screw portion is formed in the outer tube 28 by this groove as shown in FIG. 208 will be formed.

In addition, as shown in FIG. 12, in the tube plate 5 (the connection portion between the outer tube 28 of the double tube 27 and the first chamber 19 of the water chamber 17), a sleeve (tubular shape) is provided around the outer tube 28. Member) 209 is inserted. An upper end portion 209 a of the sleeve 209 is attached to the overlay portion 42 by strength welding 210. Further, the end portion 28 a of the outer tube 28 of the double tube 27 is attached to the upper end portion 209 a of the sleeve 209 by strength welding 211.

As shown in FIG. 12, the outer tube 28 of the double tube 27 and the sleeve 209 are fitted so that there is no gap between them, and the sleeve 209 and the tube plate 5 are fitted so that there is no gap between them. Match. Therefore, even if the double pipe 27 in the shell 2 is vibrated by the flow of the process gas, the influence is not exerted on the strength welds 210 and 211.

Also, the outer diameter of the sleeve 209 is larger than the outer diameter of the portion of the outer tube 28 of the double tube 27 where the second screw portion 208 is provided. Therefore, when the outer pipe 28 of the double pipe 27 leaks and the double pipe 27 is removed, the sleeve 209 is removed first, whereby the outer pipe 28 of the double pipe 27 passes through the pipe plate 5 and the tube plate 5 is removed. It is possible to pull up to the upper water chamber 17.

Next, when the double pipe leaks in the waste heat boiler 201 according to this embodiment, a procedure for taking out the double pipe will be described with reference to the drawings.
FIG. 13 is a cross-sectional view of the entire waste heat boiler according to the second embodiment, showing a process of taking out a leaked double pipe. In FIG. 13, illustration of tie rods and spacers is omitted for explanation.

As shown in FIG. 13, when the outer pipe 28 of the double pipe 27 leaks, the operation of the plant is first stopped. Thereafter, an operator enters the water chamber 17 and performs the following operations.
First, the locking nut 49 (see FIG. 9) screwed into the first tube holding member 44 (see FIG. 9) is removed, and the first tube holding member 44 is removed from the partition plate 18 (see FIG. 9).
Next, the partition plate 18 in the water chamber 17 is removed. Thereafter, the inner pipe 29 (see FIG. 9) of the double pipe 27 is pulled up. At this time, as shown in FIG. 13, the worker takes out the inner tube 29 from the water vapor outlet nozzle 22 or the manhole 23 while cutting the inner tube 29 at an appropriate position.

Next, the strength weld 210 (see FIG. 12) between the sleeve 209 and the tube plate 5 is removed, and the strength weld 211 between the outer tube 28 and the sleeve 209 is removed. Thereafter, the sleeve 209 is pulled out from the tube plate 5.
After pulling out the sleeve 209, the outer tube 28 of the double tube 27 is pulled up. At this time, since the first screw portion 207 of the baffle plate 31 and the second screw portion 208 of the outer tube 28 are screwed together, the outer tube 28 is turned to remove all screwed portions and then The tube 28 is pulled up. Here, the worker takes out the outer tube 28 from the water vapor outlet nozzle 22 or the manhole 23 while cutting the outer tube 28 at an appropriate position.

Next, as shown in FIG. 14, the plug 212 is disposed at the place where the double tube 27 is removed. The plug 212 has the same outer diameter as the sleeve 209, and the plug 212 and the tube plate 5 are fitted so that there is no gap between them. Finally, the upper end portion 212 a of the plug 212 is attached to the overlay portion 42 by strength welding 213.
With the above procedure, the removal of the leaked double tube 27 is completed.

According to the waste heat boiler 201 according to the present embodiment, a plurality of tie rods 202 that extend along the vertical direction of the shell 2 and support the baffle plate 31 disposed on the upper portion of the shell 2, and around the tie rods 202. The first screw portion 207 is formed in the hole 34 of the baffle plate 31 disposed at the lower part of the shell 2 and is provided with a spacer 203 for holding the gap between the baffle plates 31. A second screw portion 208 is formed at a position corresponding to the first screw portion 207 in the outer tube 28 of the tube 27, and the first screw portion 207 of the baffle plate 31 and the outer tube 28 of the double tube 27 are formed. Since the baffle plate 31 arranged at the lower part of the shell 2 is supported by screwing with the second screw part 208, the baffle plate 31 arranged at the upper part of the shell 2 is supported by the tie rod 202. Supported by Baffles 31 arranged in the lower part of the E le 2 is supported by the double pipe 27.
Conventionally, the baffle plate 66 at the bottom of the shell 62 is supported by the tie rod 82 and the spacer 81 (see FIG. 15). However, according to the present invention, the baffle plate 31 at the bottom of the shell 2 is a bar-like member and spacer. Instead, it is supported only by the double pipe 27. Therefore, there is no problem that the tie rod 82 and the spacer 81 are buckled by the high temperature process gas in the lower part of the shell 66 as in the prior art. In this embodiment, since the tie rod 202 and the spacer 203 are not arranged in the lower part of the shell 2, when the waste heat boiler 201 is operated, the double tube 27 and the heat transfer tube 24 and the baffle plate 31 are the same in the vertical direction. Therefore, deformation and damage of the baffle plate 31 can also be prevented.
On the other hand, since the temperature of the process gas is low at the upper part of the shell 2 of this embodiment, even if the baffle plate 31 is supported by the tie rod 202 and the spacer 203, the tie rod 202 and the spacer 203 will not buckle.

According to the waste heat boiler 201 according to the present embodiment, the sleeve 209 is fitted around the outer tube 28 of the double tube 27 in the tube plate 5, and the outer diameter of the sleeve 209 is the second diameter of the outer tube 28. This is larger than the outer diameter of the portion where the screw portion 208 is provided. According to this configuration, by removing the sleeve 209 first from the tube plate 5, a space for allowing the outer tube 28 of the double tube 27 to pass through the tube plate 5 can be created. Therefore, in the configuration in which the second screw portion 208 is provided on the outer tube 28 of the double tube 27, the double tube 27 is connected to the water chamber 17 on the upper side of the shell 2 even when the outer tube 28 of the double tube 27 leaks. The double pipe 27 can be removed.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications and changes can be made based on the technical idea of the present invention.

DESCRIPTION OF SYMBOLS 1 Waste heat boiler 2 Shell 3 Shroud 4 Refractory heat insulating material 5 Tube plate 17 Water chamber 18 Partition plate 19 First chamber 20 Second chamber 24 Heat transfer tube 27 Double tube 28 Double tube outer tube 29 Double tube Inner tube 31 Baffle plate 32 Baffle plate first plate member 33 Baffle plate second plate member 37

Bypass pipes

44 and 51

Tube holding members

45 and 52 Screw holes 46 and 53 Screw grooves 47 of the tube holding member Stepped portion 202 Tie rod 203 Spacer 207 First screw portion 208 of baffle plate Second screw portion 209 of outer tube Sleeve 212 Plug

Claims

A waste heat boiler that generates steam using waste heat discharged from plant equipment,
An outer shell formed in a cylindrical shape extending in the up-down direction, and configured so that process gas discharged from the plant equipment flows into a lower end portion;
A water chamber provided at an upper part of the outer shell and provided with a first chamber into which water is supplied; and a second chamber into which water and water vapor after heating flow in;
A plurality of heat transfer tubes extending downward from the first chamber of the water chamber, folded back at a lower portion of the outer shell, and connected to the second chamber of the water chamber;
A plurality of plate-like members extending in a direction orthogonal to the plurality of heat transfer tubes and arranged in parallel along the vertical direction of the outer shell;
A waste heat boiler, comprising: a bypass pipe extending from an upper part of the outer shell along a vertical direction of the outer shell to a lower part of the outer shell and discharging the process gas flowing into the outer shell.
The waste heat boiler according to claim 1, wherein the bypass pipe passes through the water chamber and extends through the axial center of the outer shell to a lower portion of the outer shell.
An inner tube and an outer tube extending downward from the water chamber; the outer tube is connected to the first chamber of the water chamber; and the inner tube is connected to the second chamber of the water chamber. With multiple double tubes
Each of the heat transfer tubes is disposed so as to pass through the holes provided in the plurality of plate-like members, and each of the double tubes passes through the holes provided in the plurality of plate-like members and the plurality of the plurality of plate-like members. The waste heat boiler according to claim 1 or 2, wherein a plate-like member is supported.
In the second chamber of the water chamber, a first screw hole is provided at a connection portion of the double pipe with the inner pipe, and a screw groove is formed on an outer peripheral surface of the first screw hole. The cylindrical first pipe holding member is screwed, and the end portion of the inner pipe of the double pipe is attached to the second chamber via the first pipe holding member. A waste heat boiler according to claim 3.
On the inner peripheral surface of the first tube holding member, a step portion is formed at a position on the outer shell side, and the end portion of the inner tube of the double tube is fitted to the step portion, The first tube holding member is configured to be screwed into the first screw hole of the second chamber while pressing the end portion of the inner tube of the double tube with the stepped portion. The waste heat boiler according to claim 4 characterized by things.
The second chamber of the water chamber is provided with a second screw hole at the position of the heat transfer tube, and the second screw hole has a cylindrical second shape in which a screw groove is formed on the outer peripheral surface. The ferrule is inserted into the heat transfer tube, and the end portion of the ferrule inserted into the heat transfer tube is inserted into the heat transfer tube via the second tube holding member. The waste heat boiler according to any one of claims 1 to 5, wherein the waste heat boiler is attached to the second chamber.
On the inner peripheral surface of the second tube holding member, a step portion is formed at a position on the outer shell side, and the end portion of the ferrule is fitted to the step portion, and the second tube holding member 7. The waste according to claim 6, wherein the ferrule is configured to be screwed into the second screw hole of the second chamber while pressing the end portion of the ferrule with the stepped portion. Thermal boiler.
A plurality of bar-shaped members extending along the vertical direction of the outer shell and supporting the plate-shaped member disposed on the upper portion of the outer shell;
A spacer disposed around the rod-shaped member, and for maintaining a gap between the plate-shaped members;
A first screw portion is formed in the hole of the plate-like member arranged at the lower portion of the outer shell, and each double pipe has a second screw at a position corresponding to the first screw portion. Part is formed,
As the first screw portion of the plate-like member and the second screw portion of the double pipe are screwed together, the plate-like member disposed at the lower portion of the outer shell is supported. The waste heat boiler according to any one of claims 3 to 5, wherein the waste heat boiler is configured.
A cylindrical member is disposed around the outer tube at a connection portion between the outer tube of the double tube and the first chamber of the water chamber, and the outer diameter of the cylindrical member is The waste heat boiler according to claim 8, wherein the waste heat boiler is larger than an outer diameter of a portion of the double pipe where the second screw portion is provided.