JPH09280546A - Ash deposition preventing structure of damper blade - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a damper blade from being fixed and hence easily and rapidly open the damper blade even when a boiler is operated in the state where the damper blade is closed over a long period of time. SOLUTION: An economizer bypass duct 9 is adapted such that part of combustion gas fed toward and economizer side in a rear heat transfer part is capable of being bypassed upstream the economizer. A damper blade 13 is provided in the economizer bypass duct 9 such that it is free to open and close by a fluid pressure cylinder 19. Blade receptors 20, 21, 22 for receiving the tip end of the damper blade 13 are provided, and many air jet holes 20a, 21b, 22a are provided in the damper blade 13 such that pressurized air A introduced from an air supply pipe 23 to the blade receptors 20, 21, 22 is jetted toward an abutment part of the damper blade 13 and the blade receptors 20, 21, 22 and toward the neighbourhood of the same.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ash adhesion preventing structure for a damper blade provided in a bypass duct for a economizer.

[0002]

2. Description of the Related Art An example of a conventional boiler is shown in FIG. 6, in which 1 is a boiler body. The boiler body 1 includes a furnace 3 having a burner 2 at a lower portion thereof, a secondary side wall 4 integrally connected to a rear portion of an upper portion of the furnace 3, a rear side wall of the secondary side wall 4 extending downward, and an internal lower portion. It consists of a rear heat transfer section 6 that houses a economizer 5.

An exhaust gas duct 7 for guiding the combustion gas GB passing through the economizer 5 as boiler exhaust gas GE is connected to the lower part of the rear heat transfer section 6 so as to be located below the economizer 5. A denitration device 8 is provided in the middle of the exhaust gas duct 7.

Boiler exhaust gas GE of the denitration device 8 at a position above the economizer 5 of the rear heat transfer part 6 and in the exhaust gas duct 7.
The upstream required position in the flow direction means the economizer bypass duct 9
And a damper device 10 is installed in the middle of the economizer bypass duct 9.

Such a damper device 10 is shown in FIGS. 7 and 8, and in the economizer bypass duct 9, two damper shafts extending horizontally in the width direction at predetermined intervals in the vertical direction. 1
1 is stored. Thus, both ends of each damper shaft 11 are bearings 12 installed outside the economizer bypass duct 9.
Is rotatably fitted to

Two damper blades 13 located in the bypass duct 9 of the economizer are provided on the outer circumference of each damper shaft 11 so as to extend in directions opposite to each other with respect to the damper shaft 11.
The damper blades 13 are fixedly installed with a phase shift of 0 degrees, and the damper blades 13 stand substantially vertically to close the economizer bypass duct 9, and to make the damper blades 13 substantially horizontal, so that the economizer bypass duct 9 is installed.
Can be fully opened.

One end of each damper shaft 11 horizontally projects outward from the bearing 12, and the levers 15 are vertically projected through the boss 14 in the same direction so as to be parallel to each other. The upper and lower levers 15 are attached to each other, and the tips of the upper and lower levers 15 are connected to each other via a pin 17 by a link 16 extending substantially vertically. Thus, the center of the upper damper shaft 11, the center of the lower damper shaft 11, the center of the pin 17 that pivotally attaches the tip of the lower lever 15 and the lower end of the link 16, the upper end of the link 16 and the upper lever 15. A parallelogram link is formed by a line connecting the center of the pin 17 pivotally attached to the tip and the center of the upper damper shaft 11.

An operating arm 18 is fixed to the upper boss 14 so as to extend in the direction opposite to the lever 15 with a phase shift of approximately 180 degrees.
The tip of a piston rod 19a of the fluid pressure cylinder 19 is pivotally attached.

At the upper end of the economizer bypass duct 9,
When the upper damper shaft 11 is rotated and the damper blade 13 is closed, the tubular blade receiver 20 is arranged so that the upper end of the upper damper blade 13 can come into contact with the upper damper shaft 11. They are arranged in parallel.

Further, in the middle portion in the height direction inside the economizer bypass duct 9, when the upper and lower damper shafts 11 are rotated and the damper blades 13 are fully closed, the upper damper shafts are closed. A tubular blade receiver 21 configured such that the lower end of the damper blade 13 located at the lower part of 11 and the upper end of the damper blade 13 located at the upper part of the lower damper shaft 11 can contact each other.
Are arranged in parallel with the upper and lower damper shafts 11.

Further, the lower end of the damper blade 13 on the lower side abuts on the lower end of the bypass duct 9 when the lower damper shaft 11 is rotated to close the damper blade 13. The tubular blade support 22 thus obtained is arranged parallel to the lower damper shaft 11.

When the above-mentioned boiler is operated under a high load, the piston rod 19a of the fluid pressure cylinder 19 moves to the position shown in FIG.
As shown by the solid line, the damper blades 13 are in the fully retracted position.

On the other hand, the combustion gas GB produced by the combustion of the fuel injected from the burner 2 rises in the furnace 3, passes through the auxiliary side wall 4, and descends in the rear heat transfer section 6. Thus, the total amount of the combustion gas GB in the rear heat transfer portion 6 passes through the economizer 5, is discharged to the exhaust gas duct 7 as the boiler exhaust gas GE, is introduced into the denitration device 8 through the exhaust gas duct 7, After being denitrated, it passes through the exhaust gas duct 7 further downstream and is sent to the subsequent process. A heat transfer tube wall forming the furnace 3, a heat transfer tube wall forming the auxiliary side wall 4, a heat transfer tube wall forming the rear heat transfer section 6,
The unheated superheater, reheater, water, steam and the like flowing in the economizer 5 receive heat from the combustion gas GB to generate steam having a predetermined temperature and pressure.

At this time, when the boiler has a high load, the boiler exhaust gas GE is at a high temperature, and the temperature required for efficient denitration in the denitration device 8 is sufficiently secured.

On the other hand, when the boiler has a low load, the burner 2
Since the amount of fuel injected from the boiler is also small, the temperature of the combustion gas GB does not become as high as when the boiler has a high load. Therefore, the temperature of the boiler exhaust gas GE discharged to the exhaust gas duct 7 through the economizer 5 is lower than that when the boiler is under high load, and therefore, denitration in the denitration device 8 can be performed sufficiently efficiently. However, the denitration performance will be reduced.

Therefore, when the boiler has a low load, the fluid pressure cylinder 19 shown in FIG. 8 is operated to operate the piston rod 19a.
8, the operation arm 18 is rotated in the clockwise direction in FIG. 8, and the upper and lower levers 15 are rotated using the parallelogram link to open the damper blade 13 to a predetermined opening.

Therefore, a part of the combustion gas GB descending in the rear heat transfer section 6 flows into the economizer bypass duct 9 as the boiler exhaust gas GE, passes through the economizer bypass duct 9 and reaches the middle of the exhaust gas duct 7. And the remaining combustion gas GB is discharged to the exhaust gas duct 7 through the economizer 5.
The boiler exhaust gas GE flows through the exhaust gas duct 7 and joins the boiler exhaust gas GE from the economizer bypass duct 9 at the confluence with the economizer bypass duct 9.

In this way, a part of the combustion gas GB is introduced as the boiler exhaust gas GE from the economizer bypass duct 9 into the boiler exhaust gas GE in the exhaust gas duct 7 to be introduced into the denitration device 8. The temperature of the boiler exhaust gas GE can be maintained at a temperature at which denitration can be performed efficiently,
Therefore, the denitration of the boiler exhaust gas GE can be satisfactorily performed even when the boiler has a low load.

[0019]

The damper device 10 described above is used.
In this case, when the damper blade 13 is operated in a fully closed state for a long period of time, ash in the combustion gas GB adheres between the tip of each damper blade 13 and the blade receivers 20, 21, 22 or both ends of the damper blade 13 are in contact. Is attached to the gap G between the inner surface of the economizer bypass duct 9 and the damper blades 13 are in a fixed state. Therefore, when the boiler has a low load, the damper blades are pressed by the fluid pressure cylinder 19. There was a problem that there is a risk that even if it tries to open 13, it may not open.

In view of the above situation, the present invention has an object to make it possible to easily open the damper blade even after the damper blade is operated in a fully closed state for a long period of time.

[0021]

The present invention is directed to a economizer in which a part of the combustion gas fed to the economizer side in the boiler body can be bypassed on the upstream side of the economizer. Inside the bypass duct, a damper blade is installed so that it can be opened and closed by an actuator, and a tubular blade receiver that receives the tip of the damper blade is installed substantially parallel to the damper blade, and the pressurized air introduced into the blade receiver is received by the damper blade and the blade receiver. The blade receiver is provided with a large number of air ejection holes so that the air is ejected to the contact portion and its vicinity.

Further, in the present invention, the damper blades can be multistage and the blade receivers can be multistage.

In the present invention, when the damper blade is closed and the boiler is operated, pressurized air is ejected from the air ejection holes and is blown to the contact portion between the damper blade and the blade receiver and the vicinity thereof. Ashes are not attached to these portions, and therefore the damper blades are prevented from sticking, so that the damper blades can be opened easily and quickly.

[0024]

1 to 5 show an example of an embodiment of the present invention. In FIGS. 1 and 2, the same parts as those in FIGS. 7 and 8 are designated by the same reference numerals.

In the embodiment of the present invention, the air supply pipes 23, 2 respectively connected to the air supply sources on the outer ends of the economizer bypass duct 9 of the blade receivers 20, 21, 22 respectively.
4, 25 are connected so that the pressurized air A from the air supply source can be supplied into the tubular blade receivers 20, 21, 22. A large number of air ejection holes 20a, 2 are provided so that the pressurized air A introduced into 20, 21, 22 can be ejected to the contact portions of the blade receivers 20, 21, 22 and the damper blade 13 and their vicinity, respectively.
1a and 22a are provided. Air ejection holes 20a, 21a, 2
The direction of 2a is set to a position where ash can be effectively blown off (see FIGS. 3, 4, and 5).

In FIGS. 1 and 2, reference numerals 26, 27 and 28 block the other ends of the blade receivers 20, 21 and 22 so that the pressurized air A introduced into the blade receivers 20, 21 and 22 does not leak. It is a plate.

Further, the damper device 1 in the present embodiment example
0 is the air supply pipes 23, 24, 25 and the air ejection hole 20.
The configuration is substantially the same as the conventional one except that the closing plates 26, 27, and 28 are provided in parallel with a, 21a, and 22a, and thus the description thereof is omitted.

Next, the operation of the embodiment of the present invention will be described.

In the embodiment of the present invention, in order to operate the boiler under high load, when the damper blades 13 are closed for a long period of time to operate, the pressurized air A from the air supply source is used. Blade support 2 from the air supply pipes 23, 24, 25
0, 21, 22 to feed air into the air ejection holes 20a, 21
Pressurized air A from a and 22a, respectively, blade receivers 20 and 2
Injection is performed to the contact portions between the blades 1 and 22 and the damper blade 13 and the vicinity thereof. Therefore, the ash does not adhere to these parts, passes through the gap G between the damper blade 13 and the economizer bypass duct 9, and is slightly discharged through the economizer bypass duct 9 by the boiler exhaust gas GE. 7 is transported.

Therefore, ash adheres to or blocks the gap G between the blade receivers 20, 21, 22 and the tip of the damper blade 13 or between the both sides of the damper blade 13 and the inner surface of the economizer bypass duct 9. Therefore, even when it is necessary to open each damper blade 13 due to a low load of the boiler, the damper blade 13 can be opened easily and quickly by operating the fluid pressure cylinder 19. In addition,
The present invention is not limited to the above-described embodiments, and it goes without saying that various modifications can be made without departing from the scope of the present invention.

[0031]

According to the structure for preventing ash adhesion of the damper blade of the present invention, even when the damper blade is closed for a long period of time,
Since the damper blade does not stick to the blade receiver or the inner surface of the economizer bypass duct, the damper blade can be opened easily and quickly even when the damper blade is opened.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view of an example of an embodiment of an ash adhesion preventing structure for a damper blade of the present invention.

FIG. 2 is a view taken along the line II-II in FIG.

FIG. 3 is a sectional view of the upper blade receiver.

FIG. 4 is a cross-sectional view of a blade receiver in the middle stage.

FIG. 5 is a cross-sectional view of a lower blade receiver.

FIG. 6 is a side view showing an outline of boiler equipment.

FIG. 7 is a vertical cross-sectional view of an example of a conventional damper device.

8 is a VIII-VIII direction arrow view of FIG. 7. FIG.

[Explanation of symbols]

 1 Boiler main body 5 Carbon economizer 9 Carbon economizer bypass duct 13 Damper blade 19 Fluid pressure cylinder (actuator) 20, 21, 22 Blade receiver 20a, 21a, 22a Air ejection hole GB Combustion gas A Pressurized air

Claims (2)

[Claims] 1. An actuator opens and closes in a economizer bypass duct configured so that a part of the combustion gas fed to the economizer side in the boiler body can be bypassed upstream of the economizer. The damper blade is installed so that a tubular blade receiver for receiving the tip of the damper blade is installed substantially parallel to the damper blade, and the pressurized air introduced into the blade receiver is ejected to the damper blade and the blade receiver contact portion and its vicinity. To let
An ash adhesion prevention structure for damper blades, characterized in that a large number of air ejection holes are provided in the blade receiver. 2. The ash adhesion preventing structure for a damper blade according to claim 1, wherein the damper blade has multiple stages and the blade receiver also has multiple stages.