JP2011033287A - Pulverized coal burner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pulverized coal firing burner which prevents the outflow of pulverized coal mixture gas to inside a secondary air supply passage, even when the amount of secondary air is extremely reduced, and responds to increase in the amount of the secondary air. <P>SOLUTION: This pulverized coal burner includes: a burner nozzle provided on the side face of a furnace and injecting mixture gas of pulverized coal and carrying air to form flames; a mixture gas supply passage having a tip mounted with the burner nozzle and supplying the pulverized coal and carrying air; and the secondary air supply passage formed on the outer peripheral side of the mixture gas supply passage. An angle adjusting part for varying the angle of the burner nozzle to the mixture gas supply passage is provided in a mounting part of the burner nozzle to the mixture gas supply passage, and a pressure control flow passage is formed to cover the outer peripheral side of the angle adjusting part. Air having pressure higher than that within the mixture gas supply passage is introduced from an air supply source side to the secondary air supply passage to inside the pressure control flow passage. By the air introduced to inside the pressure control flow passage, the angle adjusting part is sealed. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention includes a burner nozzle that forms a flame by jetting a mixture of pulverized coal and carrier air provided on a side surface of a furnace, and a mixture supply that supplies the pulverized coal and carrier air when the burner nozzle is attached to a tip portion The present invention relates to a pulverized coal burner including a passage and a secondary air supply passage formed on the outer peripheral side of the mixture supply passage.

  Conventionally, a burner shown in FIG. 11 is known as a burner used for a pulverized coal burning boiler. FIG. 11 is a schematic cross-sectional view showing an example of a conventional pulverized coal burning burner. The burner 101 in FIG. 11 is provided on the outer peripheral side of the pulverized coal mixture supply path 102 for supplying the pulverized coal mixture 112 in which the pulverized coal and the carrier air are mixed, and the secondary air 114. Are provided, and an auxiliary air supply passage 106 that is provided on the outer periphery of the secondary air supply passage 104 and supplies auxiliary air 116 is provided. In addition, variable angle nozzles 120 and nozzles 121 for ejecting fluid into the furnace are formed on the tip (furnace) side of the supply paths (102, 104, 106).

  In the burner 101 shown in FIG. 11, the upstream end of the inner wall 122 of the variable angle nozzle 120 and the downstream end of the inner wall 132 of the secondary air supply path 104 are connected with a seal plate 136 interposed therebetween, thereby Forming. In the rotation unit 140, the angle of the angle variable nozzle 120 with respect to the secondary air supply path 104 is variable by rotating the inner wall of the angle variable nozzle 120 with respect to the inner wall 132 of the secondary air supply path 104. At this time, the outer wall 124 of the variable angle nozzle 120 rotates with respect to the outer wall 134 of the secondary air supply path 104 in accordance with the rotation of the inner wall 122 of the variable angle nozzle 120 with respect to the inner wall 132 of the secondary air supply path 104. Is configured to do.

12 is a cross-sectional view taken along line AA in FIG. 11, and FIG. 13 is a cross-sectional view taken along line BB in FIG.
As shown in FIGS. 12 and 13, the secondary air supply path 104 and the auxiliary air supply path 106 are configured by branching a common duct 158. A damper 154 is provided on the inlet side of the secondary air supply path 104, and similarly, a damper 156 is provided on the inlet side of the auxiliary air supply path 106. By adjusting the opening degree of the damper 154 and the damper 156, the inflow amount of air from the common duct 158 to the secondary air supply path 154 and the auxiliary air supply path 156 can be adjusted.
In addition, a damper 152 is also provided in the pulverized coal mixture supply path 102 in order to adjust the supply amount of the pulverized coal mixture 112 into the furnace.

  In such a burner 101 as shown in FIGS. 11, 12, and 13, by adjusting the dampers 152, 154 and 156 according to the properties of the pulverized coal to be used, The pressure is adjusted to 50 to 100 mmAq, and the pressure of the secondary air is adjusted to about 100 to 150 mmAq. That is, the dampers 152, 154, and 156 are adjusted so that the pressure of the secondary air is higher than the pressure of the pulverized coal mixture.

  However, when using coal with extremely poor ignitability, such as anthracite, it may be necessary to reduce the amount of secondary air by reducing the damper 154 in order to improve the ignitability. When such an adjustment in the decreasing direction of the extreme secondary air amount is performed, the pressure of the secondary air may extremely decrease, for example, 10 mmAq. When the amount of secondary air is extremely reduced and, as a result, the pressure of the secondary air 114 is lower than the pressure of the pulverized coal mixture 112, the pulverized coal mixture 112 is moved from the rotating unit 140 to the secondary air flow path 104 side. May flow out into the secondary air supply path 104.

  Therefore, in Patent Document 1, a resistor such as a venturi or a porous body is provided in the secondary air supply path on the downstream side of the rotating portion, and even if the amount of secondary air is extremely reduced, A technique that does not extremely reduce the pressure is disclosed. According to the technique disclosed in Patent Document 1, even if the secondary air amount is extremely decreased, the pressure in the secondary air supply path is not extremely decreased, and the pressure in the secondary air supply path is reduced to pulverized coal. It can be maintained at a pressure higher than the pressure in the mixture supply path. Therefore, it is possible to adjust the amount of secondary air extremely without causing the pulverized coal mixture to flow into the secondary air supply path.

JP 2007-232248 A

  However, in the technique disclosed in Patent Document 1, there is no problem when the adjustment for extremely reducing the secondary air amount is performed. However, when the adjustment for increasing the secondary air is performed, the secondary air supply path is used. Due to the presence of the resistor provided inside, the effect due to the sufficient increase in secondary air could not be obtained. That is, the adjustable range of the secondary air amount was narrow.

  Therefore, in view of the problems of the prior art, the present invention prevents the pulverized coal mixture from flowing out into the secondary air supply path even when the secondary air amount is extremely reduced, and the secondary air. An object of the present invention is to provide a pulverized coal burning burner that can cope with an increase in the amount.

In order to solve the above-described problems, in the present invention, a burner nozzle that forms a flame by jetting a mixture of pulverized coal and carrier air provided on the side of a furnace, and the burner nozzle is attached to a tip portion to convey the pulverized coal. In a pulverized coal burner provided with an air-fuel mixture supply path for supplying air and a secondary air supply path formed on the outer peripheral side of the air-fuel mixture supply path, an attachment portion of the burner nozzle to the air-fuel mixture supply path And providing an angle adjusting unit that makes the angle of the burner nozzle to the mixture supply path variable,
Forming a pressure adjusting flow path covering an outer peripheral side of the angle adjusting section, and supplying a higher pressure air in the pressure adjusting flow path from the air supply source side to the secondary air supply path than in the mixture supply path. The angle adjusting unit is sealed by air introduced and introduced into the pressure adjusting flow path.

As a result, the pressure adjustment flow path is always filled with higher-pressure air than the air-fuel mixture supply path. That is, the angle adjusting unit covers the outer peripheral side with air having a pressure higher than that of the air-fuel mixture supply path regardless of the pressure in the secondary air supply path.
Therefore, regardless of the pressure in the secondary air supply path, the air-fuel mixture in the mixture supply path can be prevented from flowing out into the secondary air supply path through the angle adjusting unit. That is, it is possible to prevent the air-fuel mixture from flowing out through the angle adjusting unit even when the secondary air supply amount is extremely reduced and the pressure in the secondary air supply path is extremely reduced.
Further, since no resistor is provided in the secondary air supply path, there is no obstacle in the flow of secondary air in the secondary air supply path, and it is possible to cope with an increase in the amount of secondary air. . That is, not only can the secondary air be extremely reduced, but also the secondary air can be increased, and the amount of secondary air can be adjusted in a wide range.

  The secondary air supply path has a damper in the flow path, and the air in the upstream flow path of the damper is higher in pressure than in the air-fuel mixture supply path, and in the upstream flow path from the damper. A connection channel that guides air to the pressure adjusting channel may be provided.

  Thereby, it is only necessary to provide one damper for adjusting the amount of secondary air supplied to the secondary air supply path, and it is easy to adjust the pressure of the secondary air.

  In addition, an air supply flow path through which high-pressure air flows than in the air-fuel mixture supply path is connected, and the air supply flow path is connected to the secondary air supply path via a damper without providing a throttle portion. It is preferable to connect to the pressure adjusting flow path.

  Thereby, it is necessary to provide two or more dampers for adjusting the secondary air amount, but the configuration of the pressure adjusting flow path is simplified.

  The damper may have a notch, and the pressure adjusting flow path may pass through the notch and be connected to the air supply flow path.

  Accordingly, it is only necessary to provide one damper for adjusting the amount of secondary air supplied to the secondary air supply path, and it is easy to adjust the pressure of the secondary air, and the configuration of the pressure adjustment flow path is simple. Become.

  As described above, according to the present invention, it is possible to prevent the pulverized coal mixture from flowing out into the secondary air supply passage even when the secondary air amount is extremely decreased, and to increase the secondary air amount. It is possible to provide a pulverized coal burning burner that can cope with the above.

It is a block diagram which shows the whole schematic structure of the pulverized coal burning boiler which concerns on an Example. 1 is a schematic cross-sectional view showing a pulverized coal burning burner in Example 1. FIG. It is AA sectional drawing in FIG. 2 which concerns on Example 1. FIG. It is BB sectional drawing in FIG. It is a fragmentary sectional view of the rotation part periphery of the pulverized coal burning burner in Example 1. FIG. 6 is a cross-sectional view taken along line AA in FIG. 2 according to the second embodiment. It is CC sectional drawing in FIG. It is AA sectional drawing in FIG. 2 which concerns on Example 3. FIG. It is DD sectional drawing in FIG. FIG. 10 is a view in the direction of arrow E in FIG. 9. It is a cross-sectional schematic diagram which shows an example of the conventional pulverized coal burning burner. It is AA sectional drawing in FIG. It is BB sectional drawing in FIG.

  Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the components described in this embodiment are not intended to limit the scope of the present invention unless otherwise specified, but are merely illustrative examples. Not too much.

  First, a pulverized coal burning boiler in which pulverized coal burning burners in Examples 1 to 3 of the present invention described later are used will be described with reference to FIG.

  FIG. 1 is a block diagram showing an overall schematic configuration of a pulverized coal fired boiler according to an embodiment of the present invention. A boiler 61 is installed in a vertical direction and a furnace wall 65 of the furnace 63. The combustion device 67, the flue 69 connected to the outlet of the furnace 63, the superheater 71, the reheater 73 and the economizer 75 provided from the upper part of the furnace 63 to the flue 69, and the furnace 63 A steam drum 77 provided at the top is provided.

  A large number of water pipes (not shown) extend in the vertical direction inside the furnace wall 65. Each water pipe is connected to the steam drum 77 at its upper and lower ends. The combustion device 67 includes a plurality of pulverized coal burning burners 1 (described later) attached to the lower portion of the furnace wall 65, an additional air nozzle 80 attached in the vicinity of the furnace 65 outlet, and pulverized coal burning to the pulverized coal burning burner 1. Pulverized coal supply means 81 for supplying, high temperature gas supply means 83 for supplying high temperature gas to the pulverized coal burning burner 1, and air supply means 85 for supplying combustion air to the pulverized coal burning burner 1 and the additional air nozzle 80. Is provided.

The pulverized coal supply means 81 includes a pulverized coal machine 87 for pulverizing coal supplied via a coal feeder and a meter (not shown) to a size suitable for combustion (for example, several μm to several hundred μm), and a pulverized coal machine. There is provided a coal supply pipe 89 for conveying the pulverized coal generated in 87 to the pulverized coal burning burner 1 as a pulverized coal mixture by pressurized carrier air supplied from an air source (not shown).
The carrier air is set so that the outlet temperature of the pulverized coal machine 87 is about 80 ° C. from the safety aspect of the pulverized coal machine 87.

The air supply means 85 pressurizes and supplies a pressurized ventilator (not shown), a wind box 91 provided on the outer wall of the furnace 63, and air connecting the forced ventilator, the wind box 91, and the additional air nozzle 80. A tube 93 is provided.
The combustion auxiliary air that passes through the air pipe 93 is heat-exchanged with, for example, about 360 ° C. combustion exhaust gas that passes through the flue 69 by the rotary regenerative heat exchanger 95 and is heated to 300 to 350 ° C. Supplied.
The hot gas supply means 83 is provided with an exhaust gas pipe 97 that connects the flue 69 and the coal embracing burner 70. The exhaust gas pipe 97 is connected to the flue 69 position where the temperature of the combustion exhaust gas is 800 ° C. and the oxygen content is 4% or less during rated operation, for example.

  Further, in the embodiment of the present invention, a plurality of sets of burners are combined in the vertical direction and used as an integrated type continuous in the furnace height direction.

  Hereinafter, in Examples 1 to 3, the pulverized coal burning burner of the present invention used in the pulverized coal burning boiler shown in FIG. 1 will be described.

The pulverized coal burning burner according to the first embodiment will be described with reference to FIGS. 2, 3, and 4.
FIG. 2 is a schematic cross-sectional view showing the pulverized coal burning burner in the first embodiment.
The burner 1 in FIG. 2 is provided on the outer periphery of the pulverized coal mixture supply path 2 for supplying the pulverized coal mixture 12 in which the pulverized coal and the carrier air are mixed to the furnace 63 and the outer periphery of the pulverized coal mixture supply path 2. A secondary air supply path 4 that supplies the air 14 to the furnace 63 and an auxiliary air supply path 6 that is provided on the outer periphery of the secondary air supply path 4 and supplies the auxiliary air 16 are provided. In addition, variable angle nozzles 20 and nozzles 21 for ejecting fluid into the furnace are formed on the tip (furnace 63) side of the respective supply paths (2, 4, 6).

In the burner 1 shown in FIG. 2, the upstream end of the inner wall 22 of the variable angle nozzle 20 and the downstream end of the inner wall 32 of the secondary air supply path 4 are connected to each other with the seal plate 36 interposed therebetween, thereby Forming. In the rotating unit 40, the inner wall of the variable angle nozzle 20 rotates with respect to the inner wall 32 of the secondary air supply path 4, whereby the pulverized coal mixture supply path 2 and the secondary air supply path 4 of the variable angle nozzle 20. The angle with respect to is variable. At this time, the outer wall 24 of the variable angle nozzle 20 also rotates relative to the outer wall 34 of the secondary air supply path 4 in accordance with the rotation of the inner wall 22 of the variable angle nozzle 20 relative to the inner wall 32 of the secondary air supply path 4. Is configured to do.
Further, as a characteristic configuration of the present embodiment, a pressure adjusting channel 3 is provided on the outer periphery of the pulverized coal mixture supply channel 2. The pressure adjusting flow path 3 is configured to cover the rotating portion 40 from the outer peripheral side, and has a pressure higher than that of the pulverized coal mixture 12 supplied to the pulverized coal mixture supply path 2 (described later). Is introduced.

3 is a cross-sectional view taken along line AA in FIG. 2, and FIG. 4 is a cross-sectional view taken along line BB in FIG.
As shown in FIGS. 3 and 4, the secondary air supply path 4 and the auxiliary air supply path 6 are configured by branching a common duct 58. A damper 54 is provided on the inlet side of the secondary air supply path 4 (on the common duct 58 side), and similarly, a damper 56 is provided on the inlet side of the auxiliary air supply path 6. By adjusting the opening degree of the damper 54 and the damper 56, the inflow amount of air from the common duct 58 to the secondary air supply path 4 and the auxiliary air supply path 6 can be adjusted.
Also, a damper 52 is provided in the pulverized coal mixture supply path 2 in order to make it possible to adjust the supply amount of the pulverized coal mixture 12 into the furnace.

  Further, the pressure adjusting flow path 3 provided so as to cover the rotating portion 40 on the outer peripheral side of the pulverized coal mixture supply path 2 is opened in the common duct 58 on one end side upstream of the dampers 54 and 56. ing. With such a configuration, the air in the common duct 58 is introduced into the pressure adjusting flow path 3.

Next, the configuration around the rotating portion 40 of the pressure adjusting flow path 3 will be described with reference to FIG.
FIG. 5 is a partial cross-sectional view of the vicinity of the rotating portion 40 of the pulverized coal burning burner in Embodiment 1, and corresponds to an enlarged view of the periphery of the rotating portion 40 in FIG.
As described above, the upstream end of the inner wall 22 of the variable angle nozzle 20 and the downstream end of the inner wall 32 of the secondary air supply path 4 are connected with the seal plate 36 interposed therebetween to form the rotating portion 40. Further, the upstream end of the outer wall 24 of the secondary air supply path 4 and the downstream end of the outer wall 34 of the secondary air supply path 4 are similarly connected to form a rotating portion 42. The rotation unit 42 is configured to rotate in accordance with the rotation of the rotation unit 40.

  Further, the pressure adjusting flow path 3 has an upstream outer wall 13a whose outer wall is connected to the common duct 58 as shown in FIGS. 2, 3, and 4, and a downstream outer wall fixed to the inner wall of the angle variable nozzle 20. 13b. A rotating portion 13c similar to the rotating portion 42 is formed between the upstream outer wall 13a and the downstream outer wall 13b, and the rotating portion 13c rotates in accordance with the rotation of the rotating portion 40. It is configured.

2 to 5 as described above, the pressure adjusting flow path 3 is always filled with air having the same pressure as that in the common duct 58.
The air having the same pressure as that in the common duct 58 filled in the pressure adjusting flow path 3 is higher in pressure than the pulverized coal mixture 12 supplied to the pulverized coal mixture supply path 2. That is, the rotating portion 40 is covered with air having a higher pressure than the pulverized coal mixture supply path 2 on the outer peripheral side regardless of the pressure in the secondary air supply path 4.
Therefore, the pulverized coal mixture 12 in the pulverized coal mixture supply path 2 is prevented from flowing into the secondary air supply path 4 through the rotating portion 40 regardless of the pressure in the secondary air supply path 4. can do. That is, the secondary air supply amount is extremely reduced, and even when the pressure in the secondary air supply path 4 is extremely reduced, the pulverized coal mixture is prevented from flowing out through the rotating portion. Can do.
Furthermore, since no resistor is provided in the secondary air supply path 4, there is no obstacle in the flow of the secondary air in the secondary air supply path 4, and the increase in the secondary air can be handled. Can do. That is, not only can the secondary air be extremely reduced, but also the secondary air can be increased, and the amount of secondary air can be adjusted in a wide range.

  At this time, there is a possibility that the air in the pressure adjusting path 3 flows out into the secondary air supply path 4 through the rotating portion 13c, but this is not a problem.

The pulverized coal burning burner in Example 2 will be described with reference to FIGS. 2, 5, 6, and 7.
2 and 5 are diagrams showing the pulverized coal burning burner in the first embodiment. However, since the same shape is obtained in the second embodiment, the second embodiment is the same as the pulverized coal burning in the second embodiment. It will be described as a schematic sectional view of the burner.
6 is a cross-sectional view taken along the line AA in FIG. 2 and corresponds to FIG. 3 in the first embodiment. 7 is a cross-sectional view taken along the line C-C in FIG. 6, and is a cross-sectional view corresponding to FIG. 4 in the first embodiment.

In the second embodiment, as shown in FIGS. 6 and 7, the secondary air supply path 4, the auxiliary air supply path 6, and the pressure adjustment flow path 3 are configured by branching a common duct 58. Yes. A damper 54 is provided on the inlet side (common duct side) of the secondary air supply path 4, and similarly, a damper 56 is provided on the inlet side of the auxiliary air supply path 6. The pressure adjusting flow path 3 is not provided with a damper.
By adjusting the opening degree of the damper 54 and the damper 56, the inflow amount of air from the common duct 58 to the secondary air supply path 4 and the auxiliary air supply path 6 can be adjusted.
In addition, since the damper is not provided in the pressure adjusting channel 3, the air in the common duct 58 is introduced into the pressure adjusting channel 3 without changing the pressure.
Also, a damper 52 is provided in the pulverized coal mixture supply path 2 in order to make it possible to adjust the supply amount of the pulverized coal mixture 12 into the furnace.

As described above, the pressure adjusting duct configured as shown in FIGS. 6 and 7 has a configuration as shown in FIG.
At this time, the air in the common duct 58 is introduced into the pressure adjusting flow path 3 without changing its pressure as described above. Therefore, regardless of the pressure in the secondary air supply path 4, the rotating part 40 is covered with air having a higher pressure than that of the pulverized coal mixture supply path 2.
Therefore, the pulverized coal mixture 12 in the pulverized coal mixture supply path 2 is prevented from flowing out into the secondary air supply path 4 through the rotating portion 40 regardless of the pressure in the secondary air supply path 4. can do. That is, the secondary air supply amount is extremely reduced, and even when the pressure in the secondary air supply path 4 is extremely reduced, the pulverized coal mixture is prevented from flowing out through the rotating portion. Can do.
Furthermore, since no resistor is provided in the secondary air supply path 4, there is no obstacle in the flow of the secondary air in the secondary air supply path 4, and the increase in the secondary air can be handled. Can do. That is, not only can the secondary air be extremely reduced, but also an increase in secondary air can be accommodated, and the amount of secondary air can be adjusted over a wide range.

In the case of the configuration of the first embodiment described with reference to FIGS. 2, 3, 4, and 5, it is necessary to pass the pressure adjustment flow path 3 further to the outer peripheral side than the auxiliary air supply path 6. Only one damper 54 for adjusting the amount of secondary air supplied to the secondary air supply path 4 may be provided, and it is easy to adjust the pressure of the secondary air.
On the other hand, in the case of the configuration of the second embodiment described with reference to FIGS. 2, 6, 7, and 5, it is not necessary to pass the pressure adjustment flow path 3 further on the outer peripheral side of the auxiliary air supply path 6. Although the structure of the flow path 3 is simple, it is necessary to provide two dampers 43 for adjusting the amount of secondary air supplied to the secondary air supply path 4.
The configuration of Example 1 and Example 2 in consideration of the frequency of secondary air pressure adjustment, the margin of the surrounding space, etc., depending on the shape and usage of the pulverized coal burning boiler using the pulverized coal burning burner of the present invention It is possible to select which of the configurations is used.

The pulverized coal burning burner in Example 3 will be described with reference to FIGS. 2, 5, 8, 9, and 10.
2 and 5 are diagrams showing the pulverized coal burning burner in Example 1 and Example 2. However, since Example 3 has the same shape, FIG. 2 and FIG. Will be described as a schematic cross-sectional view of the pulverized coal burning burner.
FIG. 8 is a cross-sectional view taken along the line AA in FIG. 2 and corresponds to FIG. 3 in the first embodiment. 9 is a cross-sectional view taken along the line DD in FIG. 8, and is a cross-sectional view corresponding to FIG. 4 in the first embodiment. FIG. 10 is a view taken in the direction of arrow E in FIG.

In the third embodiment, as shown in FIGS. 8, 9 and 10, the secondary air supply path 4, the auxiliary air supply path 6, and the pressure adjustment flow path 3 are branched by a common duct 58. It is configured. A damper 54 is provided on the inlet side (common duct side) of the secondary air supply path 4, and similarly, a damper 56 is provided on the inlet side of the auxiliary air supply path 6. The pressure adjusting flow path 3 is not provided with a damper.
The pressure adjusting flow path 3 is disposed through a cutout portion 54 a formed by cutting out a part of the damper 54, and the inlet portion 3 a is a planar semicircle so that the damper 54 can rotate. It has a shape. Further, a small wall 57 is provided in order to prevent air from flowing into the secondary air flow path 4 from the common duct 58 when the damper 56 is fully closed.

  With this configuration, the damper 54 that adjusts the amount of secondary air supplied to the secondary air supply path 4 without the need to pass the pressure adjustment flow path 3 further to the outer peripheral side than the auxiliary air supply path 6 is provided. It is easy to adjust the pressure of the secondary air by providing only one.

  Even when the amount of secondary air is extremely reduced, the pulverized coal mixture can be prevented from flowing out into the secondary air supply passage, and the pulverized coal can cope with an increase in the amount of secondary air. Can be used as a burning burner.

DESCRIPTION OF SYMBOLS 1 Burner 2 Pulverized coal mixture supply path 3 Pressure adjustment flow path 4 Secondary air supply path 6 Auxiliary air supply path 20 Angle variable nozzle 40 Rotation part (angle adjustment part)
54, 56 Damper 54a Notch 58 Common duct

Claims (4)

A burner nozzle that is provided on the side of the furnace to eject a mixture of pulverized coal and carrier air to form a flame, a burner nozzle that is attached to the tip of the burner nozzle and that supplies the pulverized coal and carrier air; and In a pulverized coal burner provided with a secondary air supply path formed on the outer peripheral side of the mixture supply path,
In addition to providing an angle adjusting portion that makes the angle of the burner nozzle with respect to the mixture supply path variable in the attachment portion of the burner nozzle to the mixture supply path,
Forming a pressure adjusting flow path covering the outer peripheral side of the angle adjusting portion;
Introducing high-pressure air into the pressure adjustment flow path from the air supply source side to the secondary air supply path than in the mixture supply path,
The pulverized coal burner characterized in that the angle adjusting portion is sealed by air introduced into the pressure adjusting flow path. The secondary air supply path has a damper in the flow path, and the air in the damper upstream flow path is at a higher pressure than in the mixture supply path,
The pulverized coal burner according to claim 1, further comprising a connection channel that guides air in a channel upstream of the damper to the pressure adjusting channel. An air supply passage through which high-pressure air flows than in the mixture supply passage,
The air supply channel is connected to the secondary air supply channel via a damper,
The pulverized coal burner according to claim 1, wherein the pulverized coal burner is connected to the pressure adjusting flow path without providing a throttle portion. The damper has a notch,
The pulverized coal burner according to claim 3, wherein the pressure adjusting flow path is connected to the air supply flow path through the notch.

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