JP2525783B2 - Boiler equipment - Google Patents

Description

TECHNICAL FIELD The present invention relates to a joint structure of a boiler furnace wall corner portion, and particularly to a boiler furnace wall corner portion suitable for reducing thermal stress due to a temperature difference exerted on the corner portion. Regarding the joint structure of.

[Conventional technology]

In thermal power generation and the like, a system is used in which energy from a heat source is introduced into a boiler, heat is exchanged by a heat transfer tube provided on a side wall of the boiler, and the resulting steam drives a turbine.

Generally, the boiler wall is formed by a membrane wall in which pipes and bars are continuously welded, and the joint portion of the furnace wall and the rear heat transfer wall has a complicated three-dimensional structure with the membrane walls.

That is, as shown in FIG. 4, the furnace 1 to which the heat source is supplied
A sub-side wall 2 is connected to the outlet side of the above, and a rear heat transfer wall 3 is connected adjacent to the side wall 2 to form a boiler. The boiler wall is composed of a membrane wall in which a pipe through which water or steam flows and a bar are continuously welded.

Further, the joint portion of the rear heat transfer wall 3 of the sub side wall 2 is constituted by a sub side wall bottom wall 4, a sub side wall side wall 5, a rear heat transfer wall front wall 6 and a rear heat transfer wall side wall 7, and a joint corner 8 To form. The connecting section 8 is
The structure is such that they are welded to each other to seal the gas in the furnace. In this structure, in the joining corner 8, the above-mentioned walls intersect at one point. On the other hand, the fluid in the pipe rises in the furnace 1, the front and side walls enter the ceiling wall, the rear wall rises from the sub side wall bottom wall 4 to the sub side wall 5 and flows into the separator 15 together with the ceiling fluid. The separator 15 separates steam and water, and only the separated steam is supplied to a pipe arranged on the peripheral wall of the rear heat transfer wall 3.

By the way, the temperature of the fluid in the pipe is not uniform and has a gradient along the fluid path (in particular, the side wall 2 and the rear heat transfer wall 3),
The temperature between the walls is different.

In particular, in a transient state such as the start / stop of the boiler (there are many cases of starting / stopping the boiler according to the power demand in thermal power generation), the only fluid in the pipe is water, and the furnace 1 in front of the separator 15 Since the fluid flows only through the side walls 4 and 5, the rear heat transfer wall 3 is in an empty state. Therefore, the temperature difference between the walls becomes large, and the thermal expansion difference becomes large. For this reason, the joining corner 8 needs to use a material and a construction method that are not easily affected by the temperature difference.

[Problems to be solved by the invention]

By the way, in the conventional structure as described above, since the walls having the temperature difference in the joining corner 8 are welded and joined so as to intersect at one point, the thermal expansion of the walls is mutually restrained and the structural rigidity is increased. Strain concentration due to discontinuity also overlaps, and a large thermal stress is generated in the vicinity of the joining corner 8. In a high-frequency start / stop and load change operation boiler, this thermal stress is repeated, and a fatigue crack may occur and progress, and fluid in the pipe may leak.

It is difficult to eliminate the temperature difference between the walls due to the configuration of the fluid path in the pipe, and a structure that can reduce the thermal stress even if there is a temperature difference and that can seal the gas in the furnace is required.

An object of the present invention is to provide an attachment structure of a boiler furnace wall corner portion that can reduce thermal stress due to a temperature difference between the walls with respect to the attachment corner portion.

[Means for solving problems]

MEANS TO SOLVE THE PROBLEM In order to solve the said problem, this invention forms the membrane wall by arranging the pipelines through which a fluid circulates inside, and comprises a side wall bottom wall, a side wall side wall, and a rear heat transfer wall by this membrane wall. Then, the side wall side wall and the rear heat transfer wall side wall are arranged on substantially the same plane, and the side wall bottom wall is arranged in a direction substantially perpendicular to the side wall bottom wall and the rear heat transfer wall side wall, The present invention is intended for a boiler device that has a three-dimensional structure by joining the side wall bottom wall, the side wall side wall, and the rear heat transfer wall side wall, respectively.

The connecting side wall formed by joining the side wall side wall and the rear heat transfer wall side wall is joined to the connecting side wall, and the end portion of the side wall bottom wall is joined to the connecting side wall. To do.

[Action]

As compared with the conventional case where the end portion of the sub-sidewall bottom wall is joined at the joining portion of the sub-sidewall side wall through which water flows and the rear heat transfer wall side wall through which steam flows, the present invention provides the sub-sidewall of the connecting side wall as described above. At the place where the joint between the side wall and the rear heat transfer wall side wall is removed, the end of the sub side wall bottom wall is joined to the connecting side wall, so the thermal stress due to the temperature difference between the walls is greatly reduced. be able to.

〔Example〕

 An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a perspective view showing an embodiment of the present invention.
The figure is a perspective view showing the fluid path.

As shown in FIG. 1, the auxiliary side wall bottom wall 4 arranged horizontally.
On the other hand, the side wall 5 is disposed vertically on the side of the side wall 5,
A rear heat transfer wall side wall 7 is arranged adjacent to and on the same plane as the side wall 5. At the lower end of the sub-side wall 5 is connected a part of the side wall 7 to the inlet port 9 and the remaining part to the inlet port 12.

Further, a rear heat transfer wall front wall 6 is provided so as to be orthogonal to each of the auxiliary side wall bottom wall 4 and the auxiliary side wall bottom wall 5. The lower end of the front wall 6 is connected to the inlet header 13 (see FIG. 2).

Each of the bottom wall 4, the side wall 5, and the side wall 7 is configured by integrally forming a straight pipe through which water or steam flows and a plate-shaped body that fixes and heat-transfers each straight pipe on the same plane. It forms a passage for the hot gas introduced into.

For the side wall 5 and the side wall, steam is supplied to the pipe in the wall through the inlet header 9. Between the inlet header 9 and the rear heat transfer wall inlet header 13 It is connected. The inlet header 13 is connected to a separator 15 as shown in FIG.

In addition, some of the inner wall pipes which are connected to the rear heat transfer wall side wall 7 of the sub-sidewall 5 connected to the inlet header 9 are moved to the inlet header 9 by moving in the opposite direction (closer to the center of the sidewall 5). Be combined. As shown in FIG. 1, the terminating end 4a of the side wall bottom wall 4 is joined to the plurality of tubes near the side wall of the rear side heat transfer wall of the side side wall 5 at the side wall 7 of the rear side heat transfer wall.

In the above configuration, the fitting position of the sub-side wall 5 and the rear heat transfer wall 7 having a temperature difference in the axial direction of the wall tube can be separated from the three-dimensional fitting corner portion 8 having a complicated shape. The number of attachment points between the respective walls of the compound corner portion 8 can be reduced to three locations of the sub-side wall bottom wall 5, the rear heat transfer wall front wall 6 and the rear heat transfer wall side wall 7. That is, since the temperature generation positions between the walls can be dispersed, the thermal stress due to the temperature difference between the walls of the joining corner 8 can be significantly reduced.

As described above, according to the present embodiment, it is possible to significantly reduce the thermal stress in the sub-side wall and the lower heat transfer wall lower joining portion, and it is possible to prevent the occurrence of fatigue cracks due to repeated thermal stress associated with start / stop operation. The life of the boiler can be greatly improved. As a result, high-frequency start / stop operation becomes possible.
Furthermore, since it is possible to significantly reduce the thermal stress in the joining corner portion, a complete membrane wall structure of the gas seal can be obtained without using a gas seal casing.

FIG. 3 is a perspective view showing another embodiment of the present invention. In contrast to the embodiment shown in FIG. 1, in the present embodiment, the lower portions of some of the tubes adjacent to the side wall 5 of the rear heat transfer wall 7 are moved toward the center of the side wall 7 to move the sub side wall 5. A predetermined distance is provided between the end and the end.

That is, the above-mentioned several tubes are arranged so that their upper portions are brought closer to the sub-side wall position from below the position where the sub-side wall bottom wall 4 is joined. With such a configuration, the same effect as that of the above-described embodiment can be obtained by joining the terminal end portions 4a of the sub-side wall bottom wall 4 on the plurality of tubes near the sub-side wall side wall of the rear heat transfer wall side wall 7. .

According to one implementation result of the inventors, the thermal stress in the three-dimensional joints such as the boiler side wall and the rear heat transfer wall having a temperature difference is reduced to, for example, several tens of percent, and the repetition due to the start / stop of the boiler is repeated. It was confirmed that the fatigue life with respect to thermal stress could be increased several tens of times. Moreover, it has been confirmed that the connection has a simple structure that does not require disconnection, and that it can be started and stopped frequently, for example, 50,000 times.

〔The invention's effect〕

ADVANTAGE OF THE INVENTION According to this invention, the thermal stress of the joining part resulting from the temperature difference between each wall can be reduced, without impairing the gas sealing function in a furnace.

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment of the present invention, and FIG.
FIG. 3 is a perspective view showing the connection of fluid paths in the embodiment shown in FIG. 3, FIG. 3 is a perspective view showing another embodiment of the present invention, and FIG. 4 is a perspective view showing a structural example of a boiler. 1 ... Furnace, 2 ... Secondary side wall, 3 ... Rear heat transfer wall, 4 ...
Side wall bottom wall, 5 ... Side wall side wall, 6 ... Rear heat transfer wall front wall, 7 ... Rear heat transfer wall side wall, 8 ... Connecting corner, 9,12,1
3 …… Inlet heading, 10 …… Inlet connecting tube, 11 …… Outlet heading.

Front Page Continuation (72) Inventor Taro Sakata 6-9 Takaracho, Kure City Bab Kotsk Hitachi K.K. Co., Ltd. (56) Bibliography Sho 61-141508 (JP, U)

Claims (1)

(57) [Claims] 1. A membrane wall is formed by arranging pipelines through which a fluid flows inside, and the membrane wall constitutes a side wall bottom wall, a side wall side wall and a rear heat transfer wall, and the side wall side wall is formed. And the rear heat transfer wall side wall are arranged substantially on the same plane, and the sub side wall bottom wall is arranged in a direction substantially perpendicular to the sub side wall side wall and the rear heat transfer wall side wall. And a rear heat transfer wall side wall are joined together, wherein a sub-side wall bottom wall is formed by removing the joint part of the connecting side wall formed by joining the sub-side wall side wall and the rear heat transfer wall side wall. Boiler apparatus, wherein the terminal end of the is joined to the connecting side wall.