JP2001108229A - Unburned component reducing device for furnace - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an unburned component reducing device for a furnace for reducing an unburned component in an ash content or reducing discharge of soot dust. SOLUTION: In a boiler furnace 1 having a furnace wall panel 2 having many furnace wall tubes coupled by fins, an air layer is formed along an inner surface of the panel for cooling a flame to expedite a combustion near the furnace wall. In this case, high temperature air is charged from a gas supply slit 9 of a burner at furnace wall panels 2a and 2c, raised along the panels 2a, 2c to form a high temperature air layer at a part having no upper stage burner 4 and no lower stage burner 5 to expedite a combustion on the surfaces of the panels 2a, 2c.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for reducing the unburned portion of a furnace for reducing the unburned portion in a fossil fuel-fired boiler such as pulverized coal fired, heavy oil fired, oil coke fired or the like, which performs two-stage combustion. Things.

[0002]

2. Description of the Related Art Along with the recent tightening of pollution regulations, there is a demand for a boiler furnace with a lower nitrogen oxide. As a countermeasure against such a demand, a fossil fuel-fired boiler furnace of a two-stage combustion system in which bias combustion is performed in the first stage and combustion is completed in the second stage is employed.

Conventionally, this type of fossil fuel-fired boiler furnace has
For example, it is configured as shown in FIG.

FIG. 4 shows a central portion of a boiler furnace 1. The boiler furnace 1 is formed in a rectangular parallelepiped shape by a furnace wall panel 2 in which a large number of furnace wall tubes are connected in a plane by fins, and a lower portion has a funnel shape. Hopper 3 An upper burner 4 and a lower burner 5 are provided on two opposing surfaces of the furnace wall panel 2, respectively. An over-air port 6 is provided further above the upper burner 4, and the boiler furnace 1 has a two-stage structure. It is a combustion system.

[0005] Fuel is supplied from the upper burner 4 and the lower burner 5 to perform bias combustion in the first stage, and thereafter, combustion in the second stage is performed by air supplied from the over-air port 6.

[0006] The above-described bias combustion is for causing a low air ratio combustion in a region where combustion is performed by the burners 4 and 5. It is to make it.

[0007]

As described above, the bias combustion is a low air ratio combustion. In particular, in the part of the furnace wall panel 2 where there is no burner, the flame is easily cooled and the combustion tends to be incomplete. For this reason, unburned components are generated in the flame. Unburned components cause dust. The ash after coal combustion is used as a cement material. However, if the unburned ash contains a predetermined amount or more, the ash loses its product value. Therefore, it has been necessary to reduce the unburned ash.

The present invention has been made in view of the above circumstances, and provides an apparatus for reducing unburned components of a furnace, which reduces unburned components in ash and reduces dust and dust discharged.

[0009]

SUMMARY OF THE INVENTION The present invention provides a boiler furnace having a furnace wall panel in which a number of furnace wall tubes are connected by fins, wherein an air layer is formed along the inner surface of the furnace wall panel where the flame is cooled. The present invention relates to a device for reducing unburned fuel in a furnace configured to promote combustion in the vicinity of a furnace wall, and further comprises an air port for blowing air along a furnace wall panel, and a furnace wall portion in front of the blown air. The present invention relates to an unburned portion reducing device provided with an air supply slit, and also relates to an unburned portion reducing device of a furnace provided with a corner air supply slit at a corner of a furnace. The present invention relates to a device for reducing the unburned portion of a furnace provided with an air supply slit so as to form an air layer along the furnace wall. As it promotes, the unburned matter is greatly reduced.

[0010]

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

In FIG. 1, the same components as those shown in FIG. 4 are denoted by the same reference numerals.

The boiler furnace 1 has furnace wall panels 2a, 2b, 2c, 2d in which a number of furnace wall tubes are connected in a plane by fins.
To form a rectangular parallelepiped, and the lower part is a funnel-shaped hopper 3. At the lower end of the hopper 3, a horizontal portion 3a extending in the horizontal direction is formed.

[0013] Of the furnace wall panel 2, two opposing surfaces, 2
The upper burner 4 and the lower burner 5 are provided in each of a and 2c, and the upper air burner 4 is further provided with two over-air ports 6 above the upper burner 4. The boiler furnace 1 has incomplete combustion up to the over-air port 6. , Two-stage combustion in which combustion is performed completely downstream of the over-air port 6.

Two upper air ports 7 are provided vertically on both sides of the upper burner 4 provided on the furnace wall panel 2a, and two lower air ports 8 are provided vertically on both sides of the lower burner 5. .

A required number of burner unit air supply slits 9 are provided below the lower burner 5 and between the upper burner 4 and the lower burner 5. Similarly, the furnace wall panel 2c is provided with an upper air port 7, a lower air port 8, and a burner air supply slit 9. The furnace wall panel 2b, the furnace wall panel 2
At the center of d, a required number of furnace wall air supply slits 10 are provided at the heights of the upper air port 7 and the lower air port 8 by the number of burners.

The lower end corners of the boiler furnace 1, that is, the furnace wall panel 2a and the furnace wall panel 2b, the furnace wall panel 2b and the furnace wall panel 2c, the furnace wall panel 2c and the furnace wall panel 2d, the furnace wall panel 2d and the furnace wall A required number of corner air supply slits 11 are provided at a lower end portion adjacent to the panel 2a.

Along the ridge formed by the vertical surface and the inclined surface of the hopper 3, a hopper air supply slit 12 is provided in the vertical surface, and a horizontal air supply slit 13 is provided in the horizontal portion 3a.

FIG. 2 is a partial view of the vicinity including the upper air port 7. The upper air port 7 will be described with reference to FIG.

The furnace wall tube 14 is curved symmetrically about the position where the upper air port 7 is provided. Fins 15 are provided between the furnace wall tubes 14, and an air supply port 16 is formed at the center of a portion where only the fins 15 are formed due to the curvature of the furnace wall tube 14. A tubular air supply nozzle 17 is attached to the port 16. The combustion air heated by a gas air heater (not shown) is guided to the air supply nozzle 17.

The lower air port 8 is also provided in the same manner as the upper air port 7, and combustion air heated by a gas air heater (not shown) is guided to the lower air port 8.

FIG. 3 is a partial view of the vicinity including the burner part air supply slit 9.

The burner air supply slit 9 is formed in a fin 15 provided between the furnace wall pipes 14 so as to be long in the same direction as the axis of the furnace wall pipe 14. An air supply duct (not shown) communicating with the burner unit air supply slit 9 is provided on the outer surface of the wall panel 2, and the air supply duct guides high-temperature air heated by a gas air heater (not shown).

The furnace wall air supply slit 10, the corner air supply slit 11, the hopper air supply slit 12, and the horizontal air supply slit 13 are also provided in the same manner as the burner air supply slit 9, and are not shown. The combustion air heated by the gas air heater is guided.

The operation will be described below.

The fuel is supplied from the upper burner 4 and the lower burner 5 to perform bias combustion in the first stage, and thereafter, combustion in the second stage is performed by air supplied from the over-air port 6.

The upper air port 7 and the lower air port 8
Blow more hot air. The high-temperature air blown from the upper air port 7 and the lower air port 8 is supplied to the furnace wall panel 2b,
It is blown out along the furnace wall panel 2d and further rises. High-temperature air is also injected from the furnace wall air supply slit 10,
It rises along the center part of the furnace wall panel 2b and the furnace wall panel 2d. Thus, both ends of the furnace wall panel 2b and the furnace wall panel 2d are heated by the high-temperature air blown from the upper air port 7 and the lower air port 8, and the upper air port 7,
At the center of the furnace wall panel 2b and the center of the furnace wall panel 2d to which the air blown out from the lower air port 8 does not reach, a layer of high temperature air is formed by the high temperature air injected from the furnace wall air supply slit 10, and the furnace wall panel 2b Thus, combustion on the entire surface of the furnace wall panel 2d is promoted.

The furnace wall panel 2a and the furnace wall panel 2c
Also, hot air is injected from the burner part air supply slit 9 and rises along the furnace wall panel 2a and the furnace wall panel 2c, and a layer of high temperature air is formed in a portion where the upper burner 4 and the lower burner 5 are not provided. The combustion on the surfaces of the furnace wall panels 2a and 2c is promoted.

The high-temperature air injected from the corner air supply slit 11 rises along the corner of the furnace wall panel 2 to promote combustion at the corner, and the hopper air supply slit 12,
By injecting high-temperature air from the horizontal air supply slit 13,
An oxidizing atmosphere is formed along the inner surface of the hopper 3, and combustion is promoted.

Accordingly, a high-temperature air layer is formed on the furnace wall portion where the flame is easily cooled and incomplete combustion is likely to promote combustion, so that the unburned matter is greatly reduced. The unburned content in the ash after combustion is reduced, and in the case of coal burning, the product value of the ash is improved.

In the above embodiment, the upper burner 4,
The case in which the lower burner 5 is provided on two opposing surfaces has been described, but the embodiment can be similarly implemented when provided on only one surface.
When the burner has only one surface, the flame cooling effect on the burner-facing surface is large. Therefore, when the present invention is implemented, there is a further effect of reducing unburned components.

Further, the number and positions of the air ports and the air supply slits are not limited to those in the above embodiment, and an air layer is formed in a portion where the flame is cooled or a portion where the temperature of the inner wall of the furnace is low. You can do it. Furthermore, it goes without saying that the present invention can be applied not only to a coal-fired furnace but also to a heavy oil-fired furnace, and in this case, dust is reduced.

Further, also for the existing furnace, an air supply slit is additionally formed on the fin, and the furnace wall is partially cut off.
The present invention can be implemented by, for example, replacing the port provided with a port as shown in FIG.

[0033]

As described above, according to the present invention, an air layer is formed on the furnace wall portion where the flame is easily cooled and incomplete combustion is likely to occur, and the combustion is promoted. In the case of a coal-fired furnace, the dust and the unburned ash in the burned ash are reduced, the product value of the ash is improved, and in the case of a heavy oil fired furnace, the dust is reduced. I do.

[Brief description of the drawings]

FIG. 1 is a schematic perspective view showing a main part of an embodiment of the present invention.

FIG. 2 is a partial view of the vicinity including an upper air port.

FIG. 3 is a partial view of a vicinity including a burner part air supply slit;

FIG. 4 is a diagram showing a main part of a conventional coal-fired furnace.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Boiler furnace 2 Furnace wall panel 3 Hopper 4 Upper burner 5 Lower burner 7 Upper air port 8 Lower air port 9 Burner part air supply slit 10 Furnace wall air supply slit 11 Corner part air supply slit 12 Hopper part air supply slit 13 Horizontal part air supply Air slit 14 Furnace wall tube 15 Fin

Claims (4)

[Claims] In a boiler furnace having a furnace wall panel in which a number of furnace wall tubes are connected by fins, an air layer is formed along the inner surface of the furnace wall panel where the flame is cooled, and combustion near the furnace wall is performed. An apparatus for reducing unburned components in a furnace, wherein the apparatus is configured to promote the combustion. 2. The apparatus for reducing unburned fuel in a furnace according to claim 1, wherein an air port is provided to blow air along the furnace wall panel, and a furnace wall air supply slit is provided in front of the blown air. 3. The apparatus according to claim 1, wherein a corner air supply slit is provided at a corner of the furnace. 4. The apparatus according to claim 1, further comprising a hopper at a lower portion of the furnace, and an air supply slit formed along an inner surface of the hopper to form an air layer.