JPH07119923A - Burner for pulverized coal firing boiler - Google Patents

Abstract

PURPOSE:To prevent generation of slagging at a periphery of a burner for a pulverized coal firing boiler having a burner for generating swirl flames at the center of a furnace wall. CONSTITUTION:A pulverized coal firing boiler has a furnace of a horizontal section of a square shape or a rectangular shape similar to a square shape and burners 1-4 so disposed at substantially the same level as to swirl the flames in a range from the centers of four surfaces constituting the furnace and point away from the centers by 1/4 of the horizontal length of the surfaces constituting the furnace, and comprises nozzles 5-8 provided between the adjacent burners to cast either combustion air or at least part of combustion gas. The flames of the burners on the upstream side are blown to the peripheries of the burners of the downstream side with cast gas from the nozzles 5-8 to prevent slagging.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a combustion apparatus for a pulverized coal burning boiler in which a burner is arranged in addition to a corner portion and swirl combustion is applied.

[0002]

2. Description of the Related Art FIG. 3 shows a horizontal cross-sectional view of a burner of a conventional pulverized coal burning boiler combustor. This conventional pulverized coal-fired boiler has burners 33 to 36 at the same level on the four surfaces that make up a furnace having a square-shaped horizontal cross-section, and flames 37 to 39 from the respective burners constitute the furnace. It adopts a method in which the flame itself is given a swirling force to cause swirling combustion by inclining with respect to a line orthogonal to the plane.

In this pulverized coal burning boiler, as shown by 41 to 44 in FIG. 4, the center of the wall surface of the furnace where the heat radiation is larger than that of the corner portion of the furnace and a quarter of the horizontal length of the wall surface of the furnace from the center. Burner 33-
To are arranged 36, has improved ignitability of the burner portion than when placing the burner in the furnace corners, it is possible to reduce the NO _X operation has low air ratio of the burner zone.

[0004]

DISCLOSURE OF INVENTION Problems to be Solved by the Invention Burners are arranged at the same level within the range of the center of each furnace wall surface and a point separated from the center by about a quarter of the horizontal length of the furnace wall surface to perform swirl combustion. In the conventional pulverized coal burning boiler adopted, since the flame from the swirling direction upstream side burner easily blows the downstream side burner, the ash contained in the unburned component or pulverized coal in the vicinity of the upstream part in the flame swirling direction of the burner and its Slag due to molten ash tended to be generated. Therefore, in this combustion method, the following measures had to be taken. (1) Install more desluggers in the furnace than if a burner is installed in the corner of the furnace. (2) Considering the length of the flame from the burner, the furnace cross-sectional area is made larger than when the burner is arranged at the corner of the furnace. (3) Refrain from using highly slagging coal.

The present invention solves the above-mentioned problems, and the range between the center of the four surfaces forming the furnace and the point separated from the center by about a quarter of the horizontal length of the surface forming the furnace In a pulverized coal burning boiler in which burners are arranged at approximately the same level so that the flame swirls inside, the same number of desluggers, furnace cross-sectional area, and high sluggability as those of a boiler in which burners are arranged in the furnace corners. Even if you use coal,
An object of the present invention is to provide a combustion device that can obtain stable operation without causing slugging around the burner.

[0006]

DISCLOSURE OF THE INVENTION The present invention has a furnace having a horizontal cross-sectional shape of a square or a rectangle close to a square, and the center of each of the four surfaces forming the furnace and the horizontal direction of the surface forming the furnace from the center. In a combustor of a pulverized coal burning boiler in which burners are arranged at approximately the same level so that the flame swirls within the range of a point that is about a quarter of the length of It is characterized in that a nozzle capable of introducing at least one of combustion air and a part of combustion gas is installed therebetween.

[0007]

In the present invention, at least one of combustion air (hereinafter referred to as curtain air) and a part of combustion gas of the boiler (hereinafter referred to as curtain exhaust gas) is injected between adjacent burners forming a swirling flame. To be done. By this injection, curtain air, curtain exhaust gas, or both act as curtain-shaped partitions for the upstream flame and the downstream burner, so even if the upstream flame is blown out in the downstream burner direction, it interferes with the downstream burner. Before contact with curtain air, curtain exhaust gas or both, flame and curtain air,
The curtain exhaust gas or both of them are mixed with each other, and the flame can turn its course toward the center of the furnace, which prevents the pulverized coal from being directly sprayed to the burner on the downstream side. This prevents the generation of slag around the burner.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described with reference to FIG. The furnace of the pulverized coal burning boiler has a substantially square horizontal sectional shape, and the burners 1 to 4 are arranged at the same level on each furnace wall surface. Each of the burners 1 to 4 is arranged within a range between a horizontal center of each furnace wall surface and a point separated by about a quarter of the horizontal length of each wall surface, as shown in FIG. Similar to the boiler, it produces a rotating flame in the furnace. Further, nozzles 5 to 8 for curtain air or curtain exhaust gas are provided on the wall surface of each furnace so as to be paired with each burner at the same level as the burners 1 to 4. The nozzles 5 to 8 are arranged upstream of the burners 1 to 4 in the flame swirling direction.

In this embodiment having the above construction,
The flames 9 to 12 from the burners 1 to 4 have a sufficient flame length and width that directly blow the downstream burner in the swirling combustion direction. However, the curtain air or the curtain exhaust gas 13 to 16 is introduced from the nozzles 5 to 8 for the curtain air or the curtain exhaust gas. As a result, the flame 9 from the burner 1 is partitioned by the curtain air or the curtain exhaust gas 13 injected from the nozzle 5 from the burner 2 on the downstream side in the swirling direction, and the course thereof is bent toward the furnace center. Is prevented from being directly blown onto the burner 2. Similarly, flame 1 from burners 2-4
0 to 12 are also cut off from the burner on the downstream side by the curtain air or curtain exhaust gas 14 to 16 injected from the nozzles 6 to 8 to bend the course toward the furnace center,
These flames 10 to 12 are prevented from directly spraying on the downstream burner.

Therefore, in this embodiment, stable operation can be obtained without causing slugging around each burner.

A second embodiment of the present invention will be described with reference to FIG. In this embodiment, burners 17 to 20 which generate swirling flames are provided at the same level of each furnace wall surface in the range indicated by reference numerals 41 to 44 in FIG. 4 apart from the horizontal center of each furnace wall surface. Nozzles 21 to 24 for curtain air or curtain exhaust gas are provided on the downstream side of the nozzle burner in the direction of flame rotation. 2 in FIG.
5 to 28 are flames from the burners 17 to 20,
9 to 32 are curtain air or curtain exhaust gas injected from the nozzles 21 to 24.

Also in this embodiment, curtain air or curtain exhaust gas 29 to 3 introduced from the nozzles 21 to 24.
2 acts as a partition between the flame from the upstream that swirls and the downstream burner, and the same action and effect as those of the first embodiment can be achieved.

In the first and second embodiments, the curtain air or the curtain exhaust gas is injected from each nozzle, but both nozzles may be injected from each nozzle.

[0014]

As described above, according to the present invention, the center of each of the four faces forming the furnace having a square or a horizontal cross-sectional shape close to the square and the horizontal length of the face forming the furnace from the center. In a pulverized coal-fired boiler in which the burners are arranged at approximately the same level so that the flames swirl within a range of about 1/4 of the distance, it is possible to prevent the generation of slag around the burners. It is possible to carry out stable operation without slagging around the burner even if coal with a high slugging property is used, with the same number of deslaggers and furnace cross-sectional area as those of a boiler with a burner arranged in the corner section.

[Brief description of drawings]

FIG. 1 is a horizontal sectional view of a level at which a burner according to a first embodiment of the present invention is installed.

FIG. 2 is a horizontal sectional view of a level at which a burner according to a second embodiment of the present invention is installed.

FIG. 3 is a horizontal cross-sectional view of a level in which a burner of a conventional combustion apparatus for a pulverized coal burning boiler is installed.

FIG. 4 is an installation range when a burner is installed in the center of four surfaces forming a furnace in a conventional pulverized coal burning boiler or in a position within a range of about a quarter of the horizontal length of the surface forming the furnace. It is a horizontal cross-sectional view of the boiler showing.

[Explanation of symbols]

1-4 burner 5-8 nozzle 9-12 flame from burner 13-16 curtain air or curtain exhaust gas from nozzle 17-20 burner 21-24 nozzle 25-28 flame from burner 29-32 curtain air from nozzle or Curtain exhaust gas

Claims (1)

[Claims] 1. A furnace having a square or nearly square rectangular horizontal cross-section, and the center of each of the four faces forming the furnace and a quarter of the horizontal length of the face forming the furnace from the center. In a combustor of a pulverized coal burning boiler in which burners are arranged at almost the same level so that the flame swirls within a range of a distance, combustion air and combustion gas are formed between adjacent burners forming a swirl flame. A combustor for a pulverized coal-fired boiler, which is equipped with a nozzle capable of charging at least one of a part of the above.