JP2001227703A - Blowing device of burner for pulverized coal - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a blowing device of a burner for pulverized coal, in which pulverized coal is prevented from sticking in a form of a layer on the surface of the internal case of the burner, and a possibility for ignition of the pulverized coal layer in restarting a mill is eliminated. SOLUTION: A blow nozzle 24 is provided to a necessary position of the base of the burner external case 10, the blow nozzle blows air 23 against a pulverized coal layer 22 stuck on the surface of an internal case 11 of the burner.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pulverized coal burner blower used for a coal-fired boiler.

[0002]

2. Description of the Related Art FIG. 4 shows an example of a mill and a pulverized coal burner in a general coal-fired boiler.
Among them, 1 is a coal-fired boiler body, 2 is a furnace of the boiler body 1, 3 is a pulverized coal burner for injecting and burning pulverized coal into the boiler body 1, and 4 is pulverized coal to pulverized coal. , A primary air supply pipe for supplying primary air 9 to the mill 4, a primary air shut damper 6 provided in the primary air supply pipe 5, and a pulverized coal pulverized by the mill 4. A pulverized coal pipe 8 leading to the pulverized coal burner 3 is a cut damper provided in the pulverized coal pipe 7.

A plurality of pulverized coal pipes 7 (six, A, B, C, D, E and F in the example of FIG. 4) are provided in one mill 4 and each pulverized coal burner 3 When the mill 4 is operated, the primary air shut damper 6 is opened, the primary air 9 is introduced from the primary air supply pipe 5 into the mill 4, and the coal is removed while the desired cut damper 8 is opened. It is charged into a mill 4 by a coal feeder (not shown), and the mill 4
And pulverized pulverized coal into primary air 9
Thus, the air is conveyed to the pulverized coal burner 3 through the pulverized coal pipe 7 and burned in the furnace 2 of the boiler body 1.

When the mill 4 is stopped, pulverized coal remaining in the mill 4 is purged into the furnace 2 of the boiler body 1, that is, a so-called mill purge is performed.
The pulverized coal pipe 7 and the pulverized coal burner 3 are purged while all the cut dampers 8 (A to F) are opened.

On the other hand, in the pulverized coal burner 3, as shown in FIG. 5, a burner outer cylinder 10 and a burner inner cylinder 11 are arranged concentrically. The pulverized coal inlet 12 is protruded so as to extend in the tangential direction, and the pulverized coal inlet 12 is connected to the pulverized coal pipe 7 extending from the mill 4 (see FIG. 4). Through a wind box 14 provided to cover a throat portion 13 formed on the side wall of the furnace 2, and
Is open to the throat portion 13.

The throat section 13 and the wind box 1
In the space formed between the wind box 14 and the
The air register 16 for adjusting the swirling force of the secondary air 15 for combustion supplied to the furnace 2 from the throat 13
, A plurality of inner vanes 17 for separating the secondary air 15 into the inside and the outside are arranged inside the air register 16 in the circumferential direction. And the base end of the burner inner cylinder 11 are communicated by a tertiary air pipe 18 so that
To the burner inner cylinder 11.

[0007] An oil burner 20 is removably inserted into the axial center of the burner inner cylinder 11.

In the pulverized coal burner 3 shown in FIG. 5, pulverized coal 21 pulverized by the mill 4 (see FIG. 4) is introduced into the burner outer cylinder 10 through the pulverized coal pipe 7 and the pulverized coal inlet 12. Supplied together with the primary air 9, a swirling force is applied at the base end of the burner outer cylinder 10, and flows toward the distal end while rotating in the circumferential direction between the burner outer cylinder 10 and the burner inner cylinder 11. The secondary air 15 is supplied from the wind box 14 through the air register 16 and the inner vane 17 and is supplied from the distal end of the burner inner cylinder 11. The tertiary air 19 is mixed with the tertiary air 19 and burned in the furnace 2.

[0009]

However, in the conventional case, the mill purge when the mill 4 is stopped and the purge of the pulverized coal pipe 7 and the pulverized coal burner 3 after the completion of the mill purge are simply set by a timer regardless of the coal used. Depending on the type of coal used, the pulverized coal remains on the surface of the burner inner cylinder 11 of the pulverized coal burner 3 with the pulverized coal adhered to the pulverized coal layer 22, and the pulverized coal layer 22 is formed when the mill 4 is restarted. 22 was ignited, and the pulverized coal burner 3 could be burned.

In view of such circumstances, the present invention can avoid the formation of the pulverized coal layer due to the adhesion of the pulverized coal to the inner cylinder surface of the burner, eliminate the ignition of the pulverized coal layer at the time of restarting the mill, and eliminate the pulverized coal layer. It is an object of the present invention to provide a pulverized coal burner blowing device capable of preventing burnout.

[0011]

SUMMARY OF THE INVENTION According to the present invention, a burner outer cylinder and a burner inner cylinder are arranged concentrically, and pulverized coal is disposed at a required base end portion of the burner outer cylinder so as to extend in a tangential direction. A pulverized coal burner blow device in which an inlet is protruded and a pulverized coal pipe extending from a mill is connected to the pulverized coal inlet. The present invention relates to a pulverized coal burner blower, which is provided with a blow nozzle that blows air for blowing onto the pulverized coal bed that has adhered thereto.

According to the above means, the following effects can be obtained.

[0013] When the mill is stopped, a mill purge for purging the pulverized coal remaining in the mill into the furnace of the boiler body is performed, and after the completion of the mill purge, the pulverized coal pipe and the pulverized coal burner are purged. After the completion of the mill purge,
When blowing air is blown from a blow nozzle provided on the pulverized coal burner to the pulverized coal layer attached to the burner inner cylinder surface, the pulverized coal layer is removed.

[0014]

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

FIGS. 1 to 3 show an embodiment of the present invention. In the drawings, the portions denoted by the same reference numerals as those in FIGS. 4 and 5 represent the same components. 4 and FIG. 5, but the feature of the illustrated example is that as shown in FIG. 1 to FIG.
A blow nozzle 24 that blows blowing air 23 to the pulverized coal layer 22 attached to the surface of the burner inner cylinder 11 is provided at a required position at the base end of the burner.

In the illustrated example, as shown in FIG. 2, three branch pipes 26 are branched from a supply pipe 25 for supplying the blowing air 23, and an adjusting valve 27 such as a needle valve is provided in the middle of each branch pipe 26. And a shutoff valve 28 such as a solenoid valve (# 1, # 2, # 3)
And four branch pipes 29 are branched from the respective branch pipes 26, blow nozzles 24 are respectively connected to the ends of the respective branch pipes 29, and two each of the pulverized coal burners 3 are provided. A blow nozzle 24 is provided.

Further, the pulverized coal pipe 7 after the mill purge is completed.
In addition, when the pulverized coal burner 3 is purged to some extent and the supply of the pulverized coal 21 into the pulverized coal burner 3 becomes very small, the blowing air 23 is injected from the blow nozzle 24 to enhance the blowing effect, and , Blow air 2
In order to use the pulverized coal burner 3 efficiently, the pulverized coal burners 3 are blown sequentially as pairs A and B, C and D, and E and F, respectively, as shown in FIG. , The mill motor stop signal 30 output after the completion of the mill purge is input, and the mill motor stop signal 30 is set to “0”.
When a change from “1” to “1” occurs, a delay signal that changes to “1” with a predetermined time delay (for example, 6 [min]) is output as the open signal 31 of the shutoff valve 28 of # 1. The open signal 31 of the # 1 shut-off valve 28 output from the delay timer 32 and the on-delay timer 32 is input, and the open signal 31 of the # 1 shut-off valve 28 changes from “0” to “1”. At this time, a delay signal that changes to “1” by causing a preset time delay (for example, 30 [sec]) is output to the close signal 33 of the shutoff valve 28 of # 1 and the open signal 34 of the shutoff valve 28 of # 2. Output from the on-delay timer 35 and # output from the on-delay timer 35
When the open signal 34 of the # 2 shutoff valve 28 is input and the open signal 34 of the # 2 shutoff valve 28 changes from “0” to “1”, a preset time delay (for example, 30 [sec]) )
And the delay signal which changes to "1" is transmitted to the closing signal 36 of the shutoff valve 28 of # 2 and the open signal 37 of the shutoff valve 28 of # 3.
And an open signal 37 of the # 3 shut-off valve 28 output from the on-delay timer 38, and the open signal 37 of the # 3 shut-off valve 28 is changed from "0" to "1". ”, An on-delay timer 40 that causes a preset time delay (for example, 30 [sec]) and outputs a delay signal that changes to“ 1 ”as the closing signal 39 of the shutoff valve 28 of # 3. And shut-off valve 2
8 of the control system.

Next, the operation of the illustrated example will be described.

When the mill 4 is stopped, a mill purge for purging the pulverized coal remaining in the mill 4 into the furnace 2 of the boiler body 1 is performed, and after the completion of the mill purge, the pulverized coal pipe 7 and the pulverized coal burner 3 are removed. Purge is performed, but the mill motor stop signal 30 output after the completion of the mill purge is “0”.
Changes from “1” to “1” and is input to the on-delay timer 32, a predetermined time delay (for example, 6 [mi]
n]) and a delay signal that changes to “1” is output as an open signal 31 of the # 1 shut-off valve 28, and the # 1 shut-off valve 28 is opened to blow air 23 from the supply main pipe 25. ,
Along a branch pipe 26 and a branch pipe 29 provided with a regulating valve 27 and a # 1 shut-off valve 28 on the way, it is led to a blow nozzle 24 provided in the pulverized coal burners 3 of A and B, and the blow nozzle 2
From 4, blowing air 23 is blown onto the pulverized coal layer 22 attached to the surface of the burner inner cylinder 11, and the pulverized coal layer 22 is removed.

When the open signal 31 of the # 1 shut-off valve 28 output from the on-delay timer 32 changes from "0" to "1" and is input to the on-delay timer 35, a predetermined time delay ( For example, 30 [sec]) is generated, and a delay signal that changes to “1” is output as a close signal 33 of the shutoff valve 28 of # 1 and an open signal 34 of the shutoff valve 28 of # 2, whereby the above # The first shutoff valve 28 is closed, and the # 2 shutoff valve 28 is opened instead, and the blow air 23 is supplied from the supply main pipe 25 to the branch pipe 26 provided with the regulating valve 27 and the # 2 shutoff valve 28 on the way. Through the branch pipe 29 to the blow nozzles 24 provided in the C and D pulverized coal burners 3, and blow air 23 is blown from the blow nozzles 24 to the pulverized coal layer 22 adhered to the surface of the burner inner cylinder 11. The pulverized coal layer 22 is removed. That.

When the open signal 34 of the # 2 shut-off valve 28 output from the on-delay timer 35 changes from "0" to "1" and is input to the on-delay timer 38, a predetermined time delay ( For example, 30 [sec]) is generated and the delay signal that changes to “1” is output as the closing signal 36 of the shutoff valve 28 of # 2 and the open signal 37 of the shutoff valve 28 of # 3. The shut-off valve 28 of No. 2 is closed, and the shut-off valve 28 of # 3 is opened instead, and the blowing air 23 is supplied from the supply pipe 25 to the branch pipe 26 provided with the regulating valve 27 and the shut-off valve 28 of # 2 on the way. Through the branch pipe 29 to the blow nozzles 24 provided in the pulverized coal burners 3 of E and F, and blow air 23 is blown from the blow nozzles 24 to the pulverized coal layer 22 attached to the surface of the burner inner cylinder 11. The pulverized coal layer 22 is removed. That.

When the open signal 37 of the # 3 shut-off valve 28 output from the on-delay timer 38 changes from "0" to "1" and is input to the on-delay timer 40, a predetermined time delay ( For example, a delay signal which causes 30 [sec]) and changes to "1" is output as a closing signal 39 of the # 3 shut-off valve 28, whereby the # 3 shut-off valve 28 is closed and all the fine powder Burner inner cylinder 11 of charcoal burner 3
The blow to the surface is completed.

As a result, the pulverized coal layer 22 does not remain on the surface of the burner inner cylinder 11 of the pulverized coal burner 3 regardless of the coal used and the pulverized coal layer 22 is not formed.
There is no fear that the pulverized coal layer 22 will be ignited at the time of restarting, and the pulverized coal burner 3 will not be burned.

In this manner, the formation of the pulverized coal layer 22 due to the adhesion of the pulverized coal to the surface of the burner inner cylinder 11 can be avoided, and the ignition of the pulverized coal layer 22 when the mill 4 is restarted eliminates the burning of the pulverized coal burner 3. I can do it.

The blower for a pulverized coal burner according to the present invention is not limited to the above-described example, and the diameter and the number of the blow nozzles 24 are determined based on the position of the pulverized coal adhering to the surface of the inner cylinder 11 of the burner. Needless to say, various changes can be made within a range not departing from the gist of the present invention, for example, an appropriate selection may be made according to the range.

[0026]

As described above, according to the pulverized coal burner blowing device of the present invention, it is possible to avoid the formation of the pulverized coal layer due to the adhesion of the pulverized coal to the surface of the inner cylinder of the burner, and it is possible to prevent An excellent effect of preventing burning of the pulverized coal burner by eliminating ignition of the pulverized coal layer can be achieved.

[Brief description of the drawings]

FIG. 1 is a side sectional view of an example of an embodiment of the present invention.

FIG. 2 is a view taken in the direction of arrows II-II in FIG.

FIG. 3 is a block diagram illustrating a control system of a shut-off valve according to an example of an embodiment of the present invention.

FIG. 4 is a schematic configuration diagram illustrating an example of a mill and a pulverized coal burner in a coal-fired boiler.

FIG. 5 is a side sectional view showing an example of a conventional pulverized coal burner.

[Explanation of symbols]

 Reference Signs List 3 Pulverized coal burner 4 Mill 7 Pulverized coal pipe 10 Burner outer cylinder 11 Burner inner cylinder 12 Pulverized coal inlet 22 Pulverized coal layer 23 Air for blowing 24 Blow nozzle

Claims (1)

[Claims] 1. A burner outer cylinder and a burner inner cylinder are arranged concentrically, and a pulverized coal introduction port is protruded from a required portion of a base end portion of the burner outer cylinder so as to extend in a tangential direction thereof. A pulverized coal burner blowing device in which a pulverized coal pipe extending from a mill is connected to a pulverized coal inlet, and blow air is applied to a pulverized coal layer attached to a surface of a burner inner cylinder at a required position at a base end portion of a burner outer cylinder. A blow device for a pulverized coal burner, comprising a blow nozzle for blowing air.