JPS616503A - Steam generator - 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 Field of the Invention The present invention relates to a steam generator suitable for generating a large amount of steam for business or industrial use.

Conventional Technology A steam generator that generates a large amount of steam charges fuel and combustion air through a burner into a combustion chamber surrounded by a water-cooled wall and burns it. The boiler circulating water flowing through the boiler is evaporated.

This steam generator has a combustion chamber of the size necessary to burn the fuel in a completely stable state, and the heat flux of the water-cooled wall is uniform, so that the heat transfer to the evaporator tube is stable. It is required that high reliability of the steam pipes be ensured.

By the way, conventional steam generators employ various types of combustion chambers as shown in FIGS. 8 and 12. In other words, FIG. 2 is provided in the combustion chamber 10, as shown in FIG. What was established, the first
Figure 1 shows the burner 2 installed in the corner of the combustion chamber L, the 12th
The figure shows a combustion chamber 1 in which a dividing wall 3 is provided in the center, and burners 2 are provided in each corner.

The heat load distribution in the furnace width direction in each of these types of combustion chambers is as shown in FIGS. 13 to 1, respectively. That is, Fig. 13 shows the combustion chamber in Fig. 8, and Fig. 14 shows the combustion chamber in Fig. 9.
Similarly, Fig. 15 is shown in Fig. 10, and Fig. 16 is shown in Fig. 15.
The diagrams are shown in FIG. 11 and FIG. 17 shows the heat load distribution in the furnace width direction in the combustion chamber of FIG. 12. As is clear from these figures, no matter how the burners 2 are arranged, the heat flux distribution to the water-cooled wall is not uniform, and therefore,
In order to ensure the reliability of the evaporator tube, it was necessary to design the size of the combustion chamber 1 for the maximum heat flux, or to increase the amount of circulating water in the boiler.

Problems with the Prior Art As mentioned above, in the conventional steam generator, the heat flux to the water-cooled wall of the combustion chamber is not uniform, which causes the following problems.

■ In order to ensure that the maximum heat flux does not impair the safety of the evaporation tube that forms the water-cooled wall, the combustion chamber must have a wide space, making it large.

■ The fluid weight velocity in the evaporator tube in the eastern part of the maximum heat flow must be higher than that of the evaporator tube, which has a lower heat flux, from the viewpoint of maintaining the safety of the evaporator tube. This increases the resistance of the grid, leading to increased energy consumption and increased equipment costs.

■ In equipment that uses coal as fuel, a large amount of molten coal adheres to areas of high heat flux (so-called slacking occurs, making stable operation of the equipment difficult).

In addition, the combustion chamber 1 as shown in FIG. 10 and FIG.
In the case where the entire width in the depth direction is partitioned by the dividing wall 3, the dividing wall 3 becomes a water-cooled wall or a steam-cooled wall where the internal fluid is steam, so that the combustion gas in the combustion chamber is excessively cooled.

Therefore, especially when coal or the like having poor combustibility is used as fuel, unburned matter is generated. In addition, the gas temperature at the exit of the combustion chamber will also drop, which will reduce the efficiency of the superheater and reheater placed after the exit of the combustion chamber. Lena had to make it bigger.

OBJECTS OF THE INVENTION The present invention has been made with the aim of eliminating the problems of the prior art as described above.

Means for Solving the Problems The present invention provides a heat flux equalization wall consisting of a plurality of cooling pipes extending vertically so as to pass through at least the burner installation portion of the cooling wall constituting the combustion chamber. This solves the conventional problems.

Embodiments Hereinafter, embodiments of the present invention will be described in detail with reference to FIGS. 1 to 7.

Fig. 1 shows an example of a combustion chamber in the steam generator of the present invention, which is a horizontal type combustion chamber 10 with a burner 2 provided on a water-cooled wall on one side, and heat flow through the water-cooled wall on the side where the burner 2 is provided. A bundle equalizing wall 11 is provided. Fig. 2 shows a type in which a burner 2 is provided in the tangential direction of an imaginary circle in the combustion chamber 1, and fuel and combustion air are injected in the tangential direction of the imaginary circle, so that combustion progresses in a spiral shape. A heat flux equalizing wall 11 is provided on the water cooling wall in the middle portion of the two virtual circles.

These heat flux equalization walls 11 are formed by a plurality of cooling pipes extending in the vertical direction of the combustion chamber 1 .

The combustion chamber shown in FIG. 1 is shown in more detail in FIGS. 3 to 5. Figure 3 is an overall perspective view, Figure 4 is a front view,
FIG. 5 is a side view.

That is, the combustion chamber 1 has a water-cooled peripheral wall composed of evaporation tubes, 12 is a front wall, 13 is a rear wall, 14 is a side wall, 15 is a ceiling wall, and 16 is a furnace bottom wall. A burner 2 is provided in the front wall 12 so as to penetrate into the combustion chamber 1 .

In this example, four burners 2 are provided, and a heat flux equalizing wall 11 for equalizing the heat flux is installed inside the front wall 12 in the vertical direction so as to pass through the middle part of these burners. It extends to and is provided parallel to the side wall 14. The upper and lower ends of this heat flux equalizing wall 11 are a ceiling wall 15 and a furnace bottom wall 16, respectively.
It penetrates through and is drawn out of the combustion chamber l. 17 is an outlet header, and 18 is an inlet header.

FIG. 6 shows the heat flux distribution in the furnace width direction of the front wall of the combustion chamber 1 shown in FIG.
When the heat flux equalization wall 11 is provided, the diagram A shown by the broken line
is the case where no heat flux equalizing wall 11 is provided (the conventional eighth
Diagram C shown by a dashed-dotted line shows a case where a wall corresponding to the heat flux equalizing wall 11 is provided throughout the depth direction of the combustion chamber 1 (corresponding to the conventional Fig. 10). It is a diagram.

As is clear from Fig. 6, if the heat flux equalizing wall l] is not provided, the heat flux will be maximum at the center of the front wall as shown in the diagram, and if it is provided throughout the depth direction, the heat flux will be the maximum as shown in the diagram C. The heat flux becomes minimal at the center of the front wall. However, if the heat flux equalizing wall 11 is set to an appropriate size, the heat flux can be substantially equalized across the width direction of the front wall as shown in diagram B, and the maximum heat flux can also be reduced.

Note that even in the case of the type shown in FIG. 2, if the heat flux equalizing wall 11 is not provided, as shown in FIG. 7 by diagrams A, B, and C similar to FIG. In No. 5, the maximum heat flux is created at the center of the front wall, and if a wall corresponding to the heat flux equalization wall 11 is provided throughout the depth direction, the minimum is achieved at the center as shown in diagram C. By providing the heat flux equalizing wall 11 with the same dimensions as shown in diagram B, the heat flow rate is approximately equalized across the width of the front wall, and the maximum heat flux is also reduced.

In this way, when a heat flux distribution exists in the width direction of the combustion chamber 10, the width of the water cooling wall can be adjusted by partially installing a heat flux equalizing wall in accordance with the degree of heat flux in the high heat flow eastern part. It is possible to substantially equalize the heat flux distribution in the directions.

Effects of the Invention As detailed above, according to the present invention, the following effects are achieved by lowering the maximum heat flux of the water-cooled wall forming the combustion chamber and substantially equalizing the distribution in the radial direction. can get.

■ Reducing the local maximum heat flux improves the reliability of the evaporator tube and, by extension, the water cooling wall.

- By reducing the maximum flux, it becomes possible to increase the average heat flux, and the combustion chamber can be made smaller.

■ The heat flux equalization wall is not installed across the entire depth of the combustion chamber, but has the minimum necessary dimensions, so it will not lower the combustion temperature more than necessary and inhibit combustion. Therefore, no unburned matter is generated, and the temperature of the outlet gas of the combustion chamber is not lowered.

[Brief explanation of the drawing]

Fig. 1 is a schematic cross-sectional view showing one embodiment of a combustion chamber of a steam generator according to the present invention, Fig. 2 is a schematic cross-sectional view showing another embodiment of the present invention, and Fig. 3 is similar to Fig. 1. The perspective view of the combustion chamber shown in Figure 4 is the same (the front view, Figure 5 is the same side view, and Figure 6 is the same).
The figure is an unlined diagram explaining the effect of the embodiment of FIG. 1, FIG. 7 is a line diagram explaining the effect of the embodiment f11 of FIG. 2, and FIGS. FIGS. 13 to 17 are diagrams showing heat flux distributions on the front wall of the combustion chamber corresponding to FIGS. 8 to 12, respectively; FIGS. l... Combustion chamber, 2... Burner, 11... Heat flux (other 2
Fig. 1 Fig. 2 Fig. 3 Fig. 6 Fig. 9 Fig. 13 Fig. 14 Fig. 14 Front wall of combustion chamber Fig. 10 Fig. 11 Fig. 1z Fig. 15 Fig. 16 Fig. 47

Claims (1)

[Claims] 1. A steam generator comprising a heat flux equalizing wall made up of a plurality of cooling pipes extending vertically so as to pass through at least the burner installation portion of the cooling wall constituting a combustion chamber.