JPH0615922B2 - Boiler furnace wall structure - Google Patents

Description

TECHNICAL FIELD The present invention relates to an improvement in a furnace wall structure of a boiler formed by a cooling pipe.

2. Description of the Related Art A peripheral wall of a furnace such as a boiler for power generation has a wall surface that is gas-sealed by a cooling pipe. As the structure of the wall surface, a fusion welded wall formed in a panel shape by welding adjacent cooling pipes arranged in parallel, or a fin welded wall integrally formed adjacent to each other is used.

And, in case of providing an opening for the insertion hole of the burner or the injection hole of the air in the furnace peripheral wall of such a structure, by bending the panel at the corresponding position in the out-of-plane direction of the furnace wall and projecting it. , To form an open-tube bent panel.

FIG. 1 is a side view showing a schematic shape of a boiler having an opening. Reference numeral 1 is a furnace body in which a peripheral wall is formed by a panel formed by a cooling pipe, and 2 is an opening provided in the peripheral wall of the furnace body 1.

Then, FIG. 2 is a perspective view showing an example of an opening portion of the baila furnace, and two openings 2 are formed. Further, FIG. 3 is a schematic front view of these two opening portions, and FIG. 4 is a sectional view taken along the line AA in FIGS. 2 and 3. In these figures, 3 is a cooling pipe, 4 is a flat plate into which the cooling pipe 3 is inserted, and these form a flat panel 5 of the peripheral wall of the furnace and an opening panel 6 of the opening 2 portion, respectively.

FIG. 5 is a schematic perspective view showing an arrangement example of the opening panel 6 forming the opening portion of the boiler furnace shown in FIG.
The figure is the front view, and the two 19-panel panels 6
Two openings 2 are formed.

In FIG. 5, the target position portion of, the target position portion of, and the target position portion of.

Further, although the number of the openings 2 is two in this example, it is appropriately determined according to the number of burners and the like. Further, the number of the opening panels 6 forming the openings 2 is 19 in this example, but may be appropriately determined according to the number of openings.

However, from the viewpoint of stress relaxation, it is theoretically desirable to make the shape of the upper and lower parts of the opening a polygonal surface that is as circular and spherical as possible, but it is not possible to make it a polygonal surface that approximates a spherical shape. Since it is very difficult, it is practically preferable that the upper and lower portions of the opening each have about 8 faces as shown in FIG.

Problems to be Solved by the Invention However, the conventional boiler furnace wall structure described above has the following problems.

FIG. 7 is an enlarged view of portion B in FIGS. 2 and 3, FIG. 8 is a sectional view taken along line CC of FIG. 7, and FIG. 9 is a view similar to FIG. An example in which a cooling pipe 7'is arranged in the 7th part is shown.

As is clear from these figures, the opening panel 6 is formed so as to protrude from the flat panel 5, and the intersection of the planes, that is, the ridge line 7 is formed with the flat plate 5 as a boundary. In the conventional example, the ridge line 7 at the corner and each panel 5,
Since the cooling tubes 6 are arranged in substantially the same axial direction, the flat plates 4 of the panels 5 and 6 are also arranged in the same direction as the ridge line 7.

By the way, the flat panel 5 on the peripheral wall of the furnace is exposed to the high-temperature gas in the furnace 1 and has a large heat load. On the other hand, since the panel 6 of the opening 2 is projected outward from the flat panel 5 on the peripheral wall of the furnace, the radiant heat from the inside of the furnace is considerably small, and since it is cooled by the seal air, the heat load is small.
Therefore, a temperature difference occurs between the flat panel 5 and the opening panel 6. Therefore, the flat panel 5 and the opening panel 6
Even when thermal stress is concentrated on the ridge line 7, particularly on the corners, and when a force from the outside such as a pipe connected to the opening panel 6 is transmitted, the stress is concentrated on the ridge line 7.

Due to these thermal stresses, the rigidity against bending stress generated in the outer surface direction of the panel becomes the rigidity of the flat plate 4 and the rigidity thereof is extremely small, so cracks occur in the flat plate portion, gas in the furnace leaks, or This crack has a drawback that it may reach the inner surface of the high-temperature / high-pressure cooling pipe 3 and cause a blowout accident.

The present invention has been made in order to solve the problems of the prior art as described above, and an excessive stress does not occur in a ridge portion formed by intersecting the opening panel provided in the furnace peripheral wall and the furnace peripheral wall flat panel. Thus, it is an object to provide a furnace wall structure of a boiler in which stress concentration is alleviated.

Means for Solving the Problems In order to solve the above problems, the present invention, in the furnace wall structure of the boiler, all of the ridge lines formed by intersecting the opening panel and the furnace peripheral wall flat panel provided in the furnace peripheral wall The furnace wall is formed so as to always intersect without being parallel to the axis of the cooling pipe.

Action According to the above means, all the ridge lines formed by intersecting the opening panel provided on the furnace peripheral wall of the boiler and the furnace peripheral wall flat panel are always crossed without the furnace peripheral wall being parallel to the pipe axis of the cooling pipe. Since the cooling pipe having a high rigidity always intersects with the ridge line, the stress on the ridge line portion is reduced and the stress concentration is alleviated.

Example Hereinafter, an example of the present invention will be described in detail with reference to FIGS. 10 to 13.

FIG. 10 is a schematic front view of an opening portion for explaining an embodiment of the furnace wall structure of the boiler according to the present invention, FIG. 11 is a sectional view taken along the line DD of FIG. 10, and FIG. The figure which expanded the E section of the figure, FIG. 13 is the FF sectional view taken on the line of FIG. 12, and FIG.
The same parts as those shown in FIG. 9 are designated by the same reference numerals, and overlapping description will be omitted.

As shown well in these figures, particularly in FIG. 12, the present invention is arranged so that the cooling pipe 3 crosses all the ridge lines 7 of the opening 2 formed in the peripheral wall of the furnace body 1. It was done. That is, in the conventional one, the ridge line 7 and the pipe axis of the cooling pipe 3 were in the same direction, but in the present invention,
Ridge line 7 where the opening panel 6 and the flat panel 5 intersect each other
Are formed so as to intersect with the pipe axis of the cooling pipe 3 forming each panel.

Since the direction of the stress generated on the ridge line 7 tends to be generated in the direction in which the ridge line 7 is rotated, by arranging the direction of the tube axis of the cooling pipe 3 so as to cross the ridge line 7 as described above, The rigidity of the cooling pipe 3 can prevent the force of rotating the axis of the ridge line 7 from acting. Therefore, the displacement is reduced, the stress on the ridge 7 is reduced, and the stress locally concentrated is also relieved.

As described above, according to the present invention, all of the ridge lines formed by intersecting the opening panel and the furnace peripheral wall flat panel provided on the furnace peripheral wall of the boiler are provided on the tube axis of the cooling pipe of the furnace peripheral wall. Since the cooling pipes are formed so as to cross each other without being parallel to each other and the cooling pipe having high rigidity always crosses the ridge line, stress on the ridge line portion is reduced, and stress concentration is relieved.

Therefore, in a recent power generation boiler or the like, start-up and stop are frequently performed at high temperature and high pressure, and thus the repeated stress becomes a problem, but according to the present invention, the stress generated in the ridge portion is extremely reduced. Since the size can be reduced, it is possible to prevent a blowout accident or the like due to thermal stress and provide a boiler with extremely high safety.

[Brief description of drawings]

FIG. 1 is a side view showing a schematic shape of a boiler provided with an opening,
FIG. 2 is a perspective view showing an example of an opening portion of a boiler furnace, FIG. 3 is a schematic front view of the opening portion, FIG. 4 is a sectional view taken along line AA of FIGS. 2 and 3, and FIG. Is a schematic perspective view showing an arrangement example of an opening panel forming the opening portion, FIG. 6 is a schematic front view thereof, FIG. 7 is an enlarged view of portion B in FIGS. 2 and 3, and FIG. 7 is a sectional view taken along the line CC of FIG. 7, and FIG. 9 is a view similar to FIG. 8, but showing an example in which a cooling pipe is arranged at the ridge portion. FIG. 10 is a schematic front view of an opening portion for explaining an embodiment of the furnace wall structure of the boiler according to the present invention, FIG. 11 is a sectional view taken along the line DD of FIG. 10, and FIG. FIG. 13 is an enlarged view of part E in the figure, and FIG. 13 is a sectional view taken along line FF in FIG. 1 ... Furnace body, 2 ... Opening, 3 ... Cooling tube, 4 ... Flat plate, 5 ... Flat panel, 6 ... Opening panel, 7 ... Ridge line.

Claims (1)

[Claims] 1. A ridge line formed by intersecting an opening panel provided on a furnace peripheral wall with a flat panel of the furnace peripheral wall is formed so as to always intersect without being parallel to a pipe axis of a cooling pipe of the furnace peripheral wall. The feature is the boiler wall structure of the boiler.