JPS5827213Y2 - Heat exchanger - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a heat exchanger having a double tube wall, which can be applied to land and marine boilers, etc.

A conventional heat exchanger having a double-walled plate-shaped heat exchange tube on the combustion gas passage side of the combustion chamber peripheral wall formed as a water-cooled wall tube will be explained using a boiler's radiant reheater as an example. Figure 1 shows a typical power generation boiler, and Figure 10 shows the conventional structure.
In the figure and FIG. 1/1, the peripheral wall of the boiler combustion chamber 1 is formed into a plate shape with a water-cooled pipe 2, and a radiant reheater wall pipe 4 is provided on the combustion gas passage 3 side of the water-cooled wall pipe 2. It is located.

7 is a seal plate and a molten metal part for gas-sealing between the water-cooled wall tubes 2, 2.

The radiant reheater wall tube 4 is supported by a supporting alloy 17 over the water-cooled wall tube 2.

The support alloy 17 is welded and fixed to the water-cooled wall tube 2, and the support plate 18 is welded and fixed to the radiant reheater wall tube 4.

Reheating steam is flowing inside the reheater wall tube 4, and cooling water is flowing inside the water-cooled wall tube 2.

In this case, since a metal temperature difference occurs between the water-cooled wall tube 2 and the reheater wall tube 4 during operation of the boiler, the amount of thermal expansion differs.

Therefore, the engagement portion between the support engagement alloy 17 and the support plate 18 is
In order to absorb the difference in thermal expansion in the tube axis direction due to the metal temperature difference between the water-cooled wall tube 2 and the radiant reheater wall tube 4, it has a slidable structure.

, e * e' is the elongation margin for absorbing the difference in thermal expansion in the tube axis direction due to the metal temperature difference between the water-cooled wall tube 2 and the reheater wall tube 4, and 22 is the expansion margin for connecting the reheater wall tube 4 to the rod 21. The welded parts for connection are shown.

However, the conventional device has the following drawbacks.

That is, although the structure is such that the difference in thermal expansion between the water-cooled wall tube 2 and the radiant reheater wall tube 4 can be absorbed to some extent, in this reheater wall tube 4, the difference in thermal expansion between the water-cooled wall tube 2 and the radiant reheater wall tube 4 is A temperature difference also occurs between and 4 during operation of the boiler.

Especially when starting up the boiler, the flow rate of reheated steam flowing inside the reheater wall tube 4 is extremely small, so that the amount of reheated steam flowing inside the tube between adjacent wall tubes 4 of the same wall tube is extremely small. The reheat steam flow rates are different, which causes differences in metal temperatures.

However, as described above, since the radiant reheating wall tube 4 is connected to the support plate 18 by welding, it has a structure in which the difference in thermal expansion due to metal thermal deposition cannot be absorbed.

Therefore, an excessive force is applied to the welded portion between the reheater wall tube 4 and the support plate 18 due to the difference in thermal expansion.

Furthermore, if the metal temperature difference is large, there is a risk that the welded part may be damaged or cracks may occur in the reheat wall tube 4 in the casing, resulting in a blowout accident, which is a disadvantage that hinders the safe operation of the boiler. However, it was also difficult to manufacture and had the drawback of lacking reliability.

That is, as shown in FIG. 12, the assembly method is as follows: First, some of the tubes 4 of the radiant reheater wall tubes 4 are connected to the support plate 18, and a support plate is attached to the 2 panels of water-cooled wall tubes formed in a plate shape. The alloy 11 is fixed by welding.

At this time, the welded portion 19 of the supporting alloy 11 is connected to the reheater wall tube 4.
The remaining radiant reheat wall tube 4' is shown in the figure. Insert in the direction of the arrow as shown, and then insert the reheater wall tube 4 with
' is welded and fixed to the adjacent radiant reheater wall tube 4 with a rod 21.

In this case, the support plate 18 is not welded to all of the reheater wall tubes 4', but is connected to the support plate 18 via the adjacent wall tubes 4 as described above, so that the welded portion 20 of the support plate 18 An excessive force will be generated.

Furthermore, once all the radiant reheater wall tubes 4, 4' have been assembled, the condition of the supporting hardware etc. cannot be checked, resulting in a loss of reliability of the product.

If a part of the water-cooled wall tube 2 or the radiant reheater wall tube 4 is damaged, it is not possible to repair only the damaged portion of the water-cooled wall tube 2 and the reheater wall tube 4 by removing the damaged part. If this is not possible, it is necessary to cut the rod 21 of the sound pipe or the welded part 20 of the support plate 8, which is completely unrelated to the damaged part, by reversing the assembly procedure described above, but in this case, the sound pipe There were many undesirable drawbacks, such as damage and breakage of pressure-resistant pipes such as pipes, etc., and the need for extensive repair and inspection.

The present invention was proposed in order to eliminate the above-mentioned conventional drawbacks, and the present invention was proposed on the combustion gas passage side of the combustion chamber peripheral wall or gas passage peripheral wall formed by connecting water-cooled wall tubes or steam-cooled wall tubes with each other with a seal plate. In a heat exchanger having a double-walled plate-shaped heat exchange tube panel, each of the heat exchange tubes is engaged with a support plate by an engagement alloy having an expansion allowance for absorbing a difference in thermal expansion in the upper and lower sides. 1, a penetration support hardware welded to the support plate passes through a hole provided in the seal plate, and the penetration support hardware is fixed by a fixing alloy outside the combustion chamber peripheral wall or the gas passage peripheral wall, and the seal The present invention aims to provide a heat exchanger that is easy to manufacture and has high reliability by attaching a gas seal metal fitting that covers the hole in the plate to the outside of the peripheral wall of the combustion chamber or the peripheral wall of the gas passage.

The embodiment of the present invention will be explained below with reference to the drawings (Figs. 1 to 9). Fig. 1 shows one of the power generation boilers equipped with a double wall structure in the heat exchanger showing the embodiment of the present invention. For example, 1 is the combustion chamber of the boiler, 2 is a water-cooled wall tube forming the combustion chamber 1 and the combustion gas passage peripheral wall, 3 is the combustion gas passage, and 4 is a double-walled pipe on the combustion gas passage side above the combustion chamber 1. Arranged heat exchange tubes (radiant reheater wall tubes), 5 and 6 are combustion gas passages 3
A superheater and a reheater are installed inside.

7 or T indicates a seal plate and a molten metal part for gas sealing between the water-cooled wall tubes 2.

Reference numeral 8 designates a penetrating support metal fitting, 9 a metal alloy for fixing the penetrating support metal fitting 8, and 10 a support plate for arranging the radiant reheater wall tubes 4 in a panel shape and attaching the penetrating support metal fitting 8 by welding. .

Reference numeral 11 indicates a supporting alloy for engaging the reheater wall tube 4 with the support plate 10, and reference numeral 12 indicates a groove provided in the support plate 10.
' In order to absorb the difference in thermal expansion in the tube axis direction due to the metal temperature difference between the water-cooled wall tube 2 and the reheater wall tube 4, and the thermal expansion of each of the reheater wall tubes 4, the support plate 10 and the supporting metal This is the extension provided in the object 11.

Reference numeral 13 indicates a welded fixation portion between the supporting alloy 11 and the reheater wall tube 4, 14 indicates a through hole in the penetrating support metal fitting 8 provided in the seal plate and the molten metal portion 1, and b and b' indicate the through hole 14. The gap between the penetrating support hardware 8 is shown.

Reference numeral 15 shown in FIGS. 7 and 8 denotes a support plate 1 for fixedly supporting the reheater wall tube 4 and the water cooling wall tube 2 in the double wall.
0 is an auxiliary plate for attaching the reheater wall tube 4 by welding.

The housing 16 is a gas seal metal fitting for the through hole 14 portion of the penetrating support metal fitting 8.

Hereinafter, the present invention will be described in more detail with reference to an embodiment. As shown in FIG. The reheater wall tube 4 is fixed to the water-cooled wall tube 2 at a portion A as shown in FIGS. 1 and 8.

The Bl'' 84 portion is supported in a sliding manner as shown in FIGS. 3 to 6.

By the way, a superheater and a reheater wall tube panel are generally arranged in the reheater wall tube 4 section, but especially in the case of a reheater wall tube panel, the reheater wall tube 4 is Since the flow rate of reheated steam flowing inside the pipe is extremely small, the flow rate of reheated steam inside the pipe is different between adjacent pipes, and this causes a difference in thermal expansion due to the difference in metal temperature. Sometimes,
The double wall support device of the embodiment described above is shown in FIGS. 3 to 5.
As shown in the figure, since a support alloy 11 is attached to each of the reheater wall tubes 4, the support device can sufficiently absorb even if a considerably large difference in thermal expansion occurs in practical use.

That is, in general, the metal temperature of the reheater wall tube 4 is higher than that of the water-cooled wall tube 2, and the amount of thermal expansion is greater.

In this case, the reheater wall tube 4 is installed in the section A as shown in FIGS. 7 and 8.
As shown in the figure, the penetrating support hardware 8 is passed through the seal plate of the water-cooled wall tube 2 and the through hole 14 provided in the molten metal part 1, and is fixedly supported.

This penetrating support metal fitting 8 is welded and fixed to a support plate 10 which is welded via an auxiliary plate 15 attached to the reheater wall tube 4.

Therefore, the reheater wall tube 4 is fixedly supported by the water-cooled wall tube 2 at the section A, and the reheater wall tube 4 is vertically positioned relative to the water-cooled wall tube 2 from the section A as a base point. This results in a difference in thermal expansion.

In this case, as a support mechanism for the other support points B1 to B4 of the reheater wall tube 4, it is necessary to absorb the relative thermal expansion difference with the water cooling wall tube 2. As shown, the support point portions B1 to B4 depend on the size of the reheater wall tube 4 and the water cooling wall tube 2.
(with appropriate spacing) supported by a multi-stage support device.

In addition, the penetrating support metal fitting 8 passes through the sealing plate of the water-cooled wall tube 2 and the through hole 14 provided in the molten metal part 7, and the reheater wall tube 4 is extended to the combustion gas passage 3 side by means of a fixing metal fitting 9. I support them so that they don't come out.

Furthermore, as shown in FIG. 6, the through hole 14 through which the penetrating support metal fitting 8 is penetrated is designed to prevent manufacturing errors between the water cooling wall tube 2 panel and the reheater wall tube 4 panel so that the penetrating support metal fitting 8 can be inserted easily. With this in mind, gaps s and b' are provided.

Further, as shown in FIGS. 5 and 6, the reheater wall tube 4 is engaged with the support plate 10 by a supporting alloy 11 at each front end.
The support plate 10 and the support alloy 11 are provided with elongation allowances a and a' as shown in FIG.

These elongation allowances a and a' can not only absorb the difference in thermal expansion caused by the metal temperature difference between the water-cooled wall tube 2 and the reheater wall tube 4, but also allow the reheater wall tube 4 to absorb the difference in thermal expansion that could not be solved by conventionally known means. The difference in thermal expansion due to the difference in metal temperature between the supporting alloys 11
It can be absorbed into the welded portion 13 of the reheater wall tube 4 without any difficulty.

Further, as shown in FIGS. 4 and 5, support alloys 11 are individually attached to the reheater wall tubes 4, and a large force is biased toward the welded portions 13 of the support alloys 11. There is no such thing.

Furthermore, at the engagement portion between the support plate 10 and the support engagement alloy 11,
A groove 12 is provided on the side of the support plate 10 to prevent disturbance of the reheater wall tube 4 in the width direction of the boiler (FIG. 4).

Further, the production and assembly of the double wall is as shown in FIG.
By engaging the welded support plate 10, the reheater wall tube 4 is integrated as a panel.

In this case, the 4 panels of reheater wall tubes can be completed as a single panel completely independent of the 2 panels of water cooling wall tubes,
The fixed welded portion 13 between the wall tube 4 and the support alloy 11, the gap b' between the support alloy 11 and the support plate 10, etc. ensure that the product can be inspected after assembly.

Furthermore, the heat treatment of the four panels of reheater wall tubes can be carried out separately from the two panels of water-cooled wall tubes.

On the other hand, the water-cooled wall tube panel is manufactured in the form of a seal plate and molten metal part 1 on the water-cooled wall tube 2, and then a through hole 14 for penetrating the penetrating support hardware 8 is formed, and other necessary panels are attached. After the kimono and other items are all attached, heat treatment and other processes are completed, and the panel can be completed as an independent two-panel water-cooled wall tube.

After assembling the four panels of reheater wall tubes and the two panels of water cooling wall tubes, each completed individually in this way, in the direction of the arrow as shown in FIG. By welding and fixing the parts, it is easy to assemble, and a highly reliable product with sufficient quality control can be obtained.

If the reheater wall tube 4 or the water cooling wall tube 2 is damaged due to an accident or the like and a correction inspection becomes necessary, simply remove the fixing alloy 9 and the pressure tube can be removed without cutting the pressure tube. It is possible to easily separate the water-cooled wall tube panel and the reheater wall tube panel, allowing for easy and reliable repair and inspection.

Therefore, according to the present invention, it is possible to provide a highly reliable product that eliminates the above-mentioned conventional drawbacks and has new functions.

[Brief explanation of the drawing]

Figure 1 is a front cross-sectional view showing an example of a boiler equipped with a double-walled heat exchanger according to an embodiment of the present invention;
1-1 sectional view in the figure, Figure 3 is a detailed sectional view of parts 81 to 84 in Figure 1, Figure 4 is a sectional view from 6 is a sectional view showing different embodiments; FIG. 6 is a sectional view from ■ to ■ in FIG. 3; FIG. 7 is a detailed sectional view of section A in FIG. 1; and FIG. 8 is a sectional view from IV to ■ in FIG. , FIG. 9 is an explanatory diagram showing the assembly procedure of a water cooling wall tube panel and a reheater wall tube panel showing an embodiment of the present invention, FIG. 10 is a front sectional view showing a conventional heat exchange tube support structure, and FIG. FIG. 11 is a sectional view taken along the line v-■ in FIG. 10, and FIG. 12 is an explanatory diagram showing the procedure for assembling a conventional water-cooled wall tube panel and a reheater wall tube panel. Explanation of the main parts of the diagram, 1... Combustion chamber, 2...
...Water-cooled wall pipe, 3...Combustion gas passage, 4...
... Reheater wall tube (heat exchange tube), 7 ... Seal plate, 8 ... Penetration support hardware, 9 ... Fixing metal alloy, 10. ...-Support plate, 11...
・Supporting alloy material, 14... Through hole, 16...
...gas seal hardware, ata'...extension.

Claims (1)

[Scope of utility model registration request] A heat exchanger having a double-walled plate-shaped heat exchange tube panel on the combustion gas passage side of the combustion chamber peripheral wall or gas passage peripheral wall formed by connecting water-cooled wall tubes or steam-cooled wall tubes with a seal plate. In this case, each of the heat exchange tubes is engaged with a support plate such as an engagement alloy having an expansion margin to absorb the difference in thermal expansion between the upper and lower sides, and a penetrating support metal member welded to the support plate is connected to the seal plate. the penetrating support metal fitting is fixed by a fixing metal fitting outside the combustion chamber peripheral wall or the gas passage peripheral wall;
A heat exchanger characterized in that a gas seal metal fitting that covers the hole in the seal plate is attached to the outer side of the peripheral wall of the combustion chamber or the peripheral wall of the gas passage.