JPS59189202A - Furnace wall structure - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] This concerns the furnace wall structure.

As shown in Figures 1 and 2, cooling pipes 1 and flat plates 2 are welded together to form a panel-like wall around a furnace of a power generation boiler, etc., or as shown in Figures 3 and 4, cooling pipes 4 are formed with fins. It is well known that the fin portions 5 and 5' are integrated by welding to form a so-called welted wall to form a casseal wall (3 and 6 indicate welded portions).

However, in boilers and the like, there are some parts where it is impractical to make the entire furnace wall a welted wall structure, so a structure in which intermittent fins are welded is used in some parts, as shown in Figures 5 and 6. .

In this way, the welted wall and the intermittent fin section 12
In the conventional method, as shown in FIG. 6, the welt nose portion and the interrupted fin portion are simply separated in a straight line.

In such a conventionally known structure, at the boundary between the welded wall and the intermittent fin section, at the panel end of the welded wall (section A in Figure 6), the panel becomes stiff due to the change in the rigid cross section of the furnace wall panel. The vertical and horizontal forces due to its own weight and external forces, as well as the thermal stress generated on the panel, are concentrated.

Excessive stress occurs.

For this reason, cracks may occur in the core or may extend to the inner surface of the cooling tube, resulting in the drawback of preventing blowout accidents and gas leak accidents.

In modern power generation boilers, startups and stops and load fluctuations are frequently repeated due to labor-saving measures and changes in main power demand, and the thermal stress generated on the furnace wall is also excessive, increasing the number of repetitions. In many cases, the conditions have become extremely harsh in terms of lifespan, and it is thought that the structure known since 1970 will be in an extremely dangerous condition.

In view of the above, the present invention provides an arrangement in which the end of a welded wall panel is moved in an arcuate or stepwise manner by shifting the position of the fin weld end at the boundary between the welted wall and the intermittent fin pipe or bare pipe. This reduces stress concentration at the edge of the welted wall panel, and when connecting two welted walls of different sizes, the part where the two connecting parts change to a right angle. In this method, the fin welding end position can be shifted in an arc or step shape to alleviate stress concentration at the core. Provided is a furnace wall structure consisting of a welded panel formed using a welded panel, characterized in that the terminal end portions of the fins or the molten metal are arranged in an arc shape or a stepped shape in the tube axis direction at the end portion of the welded panel. do.

According to the present invention, the end portions of the fins or molten metal are arranged in an arc or step shape in the direction of the tube axis at the end of the panel, so that stress concentration at the core is significantly alleviated, making it possible to withstand severe operating conditions. It is possible to obtain a furnace wall structure that can sufficiently withstand the conditions.

An embodiment of the present invention will be described and explained below based on the drawings.

Figure 1 shows a so-called welted panel manufactured by alternately welding cooling pipes and flat plates that form the furnace wall of power generation boilers, etc. Figure 2 is a 1-1 cross-sectional view of Figure 1, and Figure 3 is the same (Fin I τj). Figure 4 shows a lutenod pipe made by welding between the fins of the cooling pipe, and Figure 4 shows the It-
A sectional view of Il is shown. FIG. 5 shows an example of a sketch of a furnace wall of a two-generation boiler or the like. FIG. 6 shows details of part A in FIG. 5 using conventionally known means. FIGS. 7 and 8 are detailed structural diagrams of section A in FIG. 5 when the means of the present invention is used. FIGS. 9 and 10 show one embodiment of the detailed shape of the fin end.

FIG. 11 is a comparative explanatory diagram of the stress distribution situation at the panel boundary between the conventionally known means and the present invention means.

1 is a cooling pipe, 2 is a fin or molten metal, 3 is a cooling pipe (1
) and the fin (2), 4 is the finned cooling pipe 2
5 is the fin part of the fin cooling pipe (4).

6 indicates a welded portion between the fin portion (5) and the fin portion (g).

7 shows the fins or fins of the furnace feed wall; 8, 9.10 also show the side wall panels; 1
1.12. I8 indicates the ceiling cooling wall, 11
12 indicates a fin or a fusion welded panel, and 12 indicates a bare pipe section or an interrupted fin pipe section. 18 is a cooling wall (9
) Indicates a bare or finned tube at the lower end. Part A shows the end of the ceiling cooling panel, and part '11.0 shows the stepped part in the panel plane, which also occurs in the side wall panel due to the difference in the shape of the heat exchanger or the size of the panel.

Recent boilers for power generation, etc., are becoming hotter and more pressurized due to labor-saving measures and changes in electricity demand, and they are also subject to frequent rapid startup/stopping and load fluctuations2.
Thermal stress generated in the cooling tube pipes that form the furnace walls is also excessive. In particular, the conditions at the boundary where the shape of the cooling pipe panel changes are extremely severe, and conventional methods would be extremely dangerous. The present invention was developed to enable safe operation even under such severe conditions.

That is, in the conventionally known means, as shown in FIG. There is.

However, the welted panel section 11 has no cooling pipes (1).
The fins (2) are welded (3) into a single plate, and the stiffness ('1 degree) within the plate lni of the panel (11) is extremely large. The rigidity of the fin tube portion 0 is that of the individual tube i1i, which is extremely fine compared to the rigidity of the panel θl).

Therefore, when thermal stress occurs at the boundary between panels with different degrees of rigidity, the stress will be concentrated at the edge (A) of the two panels, resulting in excessive stress and frequent It is not safe as there is a risk of fatigue due to repeated starting and stopping, which may cause cracks or a blowout accident. Figure 11 shows the stress distribution in this area.

The present invention is characterized in that it has a structure that is sufficiently safe even under such frequent startup and stoppages, load fluctuations, etc.

That is, as shown in Figure S7 or Figure 8, at the boundary between panels of different rigidity, the end of the fin or molten metal is divided into a substantially straight line in the center of the panel.

By sliding the end part (A part) of the panel in a substantially arc shape or step shape, the end part (A part)
By relaxing the stress concentration that had occurred in Figure 11E as shown in Figure 11E and reducing the local stress by one area, it is possible to avoid extremely severe startup.
It can be operated safely even during stoppages and load fluctuations. It is designed to provide a heat exchanger furnace wall.

By using the arcuate or step-like welted panel edges of the present invention in parts B and o/0 in FIG. 3, it becomes completely safe.

In addition, the shape of the end of the fin (2) between each cooling pipe (1) is adapted to its function as shown in Figures 9 and 10. It can be made into a shape.

[Brief explanation of drawings]

Figures 1 and 3 are front views of the welded panel, Figure 2 is I of Figure 1.
-1 arrow view, Figure 4 is a view from 11-■ arrow in Figure 3, Figure 5 is a perspective view of the boiler furnace wall, Figure 6 is an enlarged view of the end of a conventional welded panel, Figures 7 and 8 9 is an enlarged view of the end of a welded panel according to an embodiment of the present invention, FIGS. 9 and 10 are enlarged views of the end of a fin or molten metal, and FIG. 11 is a stress distribution diagram at a boundary 11 of the welded panel. 11... Uyurtenod panel, 12... Intermittent fin pipe section, A... Welded panel end. Figure 8 Eaves/Power □ Figure 11 Figure 9 Figure 10 Figure 11-

Claims (1)

[Claims] In a furnace wall structure consisting of a welded panel formed by welding a plurality of tubes through fins or molten metal, l1ff
13 means that the fins or the terminal ends of the molten metal are arranged in an arc shape or a step shape in the direction of the tube axis at the end of the welding panel.
Characteristic furnace wall structure.