JPH08320101A - Fuel feeder for fluidized bed boiler - Google Patents

Abstract

PURPOSE: To prevent the penetration of a bed material into an ejection opening at the tip of a fuel nozzle when the flowing of the bed material is stopped. CONSTITUTION: In a fluidized bed boiler which forms a fluidized bed by fluidizing a bed material 6 by a combustion air in a boiler main body, and ejects fuel 20 from a fuel nozzle 3 into a fluidized bed, thereby burning the fuel 20, a space formation board 21 is horizontally laid out at a position directly above an ejection opening 16 and arranged so that a space 24 which surrounds the ejection opening 16 of the fuel nozzle 3 may be formed in a conical shape below the space formation board 21 by an angle of repose of the bed material 6 when the flowing of the bed material 6 is stopped. When stopping the flowing of the bed material 6, it is so arranged that no bed material 6 may penetrate the ejection opening 16 of the fuel nozzle 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel supply system for a fluidized bed boiler.

[0002]

2. Description of the Related Art There is a fluidized bed boiler as a boiler that efficiently burns solid fuel. In recent years, as a fluidized bed boiler of this type, it is possible to burn fuel with high combustion efficiency and to achieve compactness, high desulfurization rate and plant thermal efficiency. Research and development of a pressurized fluidized bed boiler that can be improved is underway.

FIG. 4 shows an example of the pressurized fluidized bed boiler. In the figure, reference numeral 1 shows a boiler main body housed in a pressure vessel 2, and below the boiler main body 1, coal water slurry or the like. A plurality of fuel nozzles 3 for ejecting the above fuel are provided (the number is one in the illustrated example for convenience of description).

An air supply pipe 4 is connected to the pressure container 2, and high-pressure air is supplied from the air supply pipe 4 to the pressure container 2 to increase the pressure in the pressure container 2 and then through an air conduit 5. The bed material 6 such as ash is fluidized by the air injected into the boiler body 1 from the air conduit 5 to form a fluidized bed, and high-pressure air (for example, about 15 The fuel is configured to burn under ˜16 Kg / cm ² ).

An exhaust gas pipe 8 having a cyclone 7 in the pressure vessel 2 is connected to the upper portion of the boiler body 1 so that the exhaust gas flowing into the exhaust gas pipe 8 via the cyclone 7 is guided to a gas turbine or the like (not shown). There is.

Further, a heat transfer tube 9 for heating water by the heat of combustion in the fluidized bed to form steam is provided in the boiler body 1, and the steam from the heat transfer tube 9 is guided to a steam turbine or the like (not shown). It is like this.

Further, a fuel tank 13 inserted into the lower portion of the boiler body 1 is connected to a fuel tank 13 via a fuel pipe 10 having a fuel pump 11, and the fuel tank 13 is connected to the fuel tank 13. A fuel supply pipe 14 to which a fuel such as coal water slurry (CWM) is supplied is connected, and the coal water slurry manufactured by a coal water slurry manufacturing device or the like is used as a fuel tank 13.
It is designed to be supplied and stored in.

A three-way valve 12 is arranged between the fuel pump 11 and the fuel nozzle 3 in the fuel pipe 10.
The three-way valve 12 and the fuel tank 13 are connected via a circulation pipe 15, and the three-way valve 12 is a fuel pump that prevents the fuel pipe 10 from being clogged with coal water slurry at the time of start-up or boiler operation interruption. Circulation pipe for coal water slurry from 11
It is returned to the fuel tank 13 via 5, and the opening and closing is adjusted so as to supply the coal water slurry to the fuel nozzle 3 during the boiler operation.

Further, as shown in FIG. 5, the fuel nozzle 3
Is formed in a cylindrical shape, and fuel 20 such as coal water slurry (CWM) is ejected from a jet port 16 opened at the tip into a fluidized bed formed by a bed material 6 in the lower part of the boiler body 1. It is supposed to be done.

A fuel dispersion air supply pipe 17 is provided at the center of the fuel nozzle 3, and a part of the air in the pressure vessel 2 shown in FIG. 4 is provided in the fuel dispersion air supply pipe 17. An air pipe 19 that is pressurized and guided via an air pump 18 is connected, and a part of the air in the pressure vessel 2 is pressurized by the air pump 18 and ejected from the tip of the fuel dispersion air supply pipe 17 into the fluidized bed. Then, the fuel 2 ejected from the ejection port 16
0 is dispersed in the fluidized bed.

In FIGS. 4 and 5, the fuel nozzle 3
Although a vertical type is shown as, the horizontal fuel nozzle 3 shown in FIG. 6 inserted into the boiler main body 1 from the lower side surface of the boiler main body 1 is also used, and such a horizontal fuel nozzle 3 is also used. A fuel dispersion air supply pipe 17 is provided in the center of the fuel nozzle 3 so that the fuel 20 ejected from the ejection port 16 at the tip of the fuel nozzle 3 is dispersed in the fluidized bed.

In such a pressurized fluidized bed boiler, fuel 20 such as coal water slurry (CWM) in the fuel nozzle 3 must be extracted when the operation of the boiler body 1 is stopped, and the coal water in the fuel nozzle 3 must be removed. Since the slurry is solidified, the three-way valve 12 connected to the fuel pipe 10 in FIG. 4 is switched, and the coal water slurry in the fuel nozzle 3 is recovered in the fuel tank 13 by the air pressure in the boiler body 1, The inside of 3 is empty.

[0013]

However, when the fluidization of the bed material 6 is stopped when the operation of the boiler body 1 is stopped, when the fuel 20 such as coal water slurry (CWM) in the fuel nozzle 3 is drained, There has been a problem that the bed material 6 whose fluidization has been stopped enters the fuel nozzle 3 through the ejection port 16 at the tip of the fuel nozzle 3 and the fuel nozzle 3 is clogged with the bed material 6 of the fluidized bed.

The present invention solves such a problem, and provides a fuel supply device for a fluidized bed boiler which prevents the bed material from entering the jet nozzle at the tip of the fuel nozzle when the fluidization of the bed material is stopped. The purpose is to do.

[0015]

According to the present invention, a bed material is fluidized by combustion air in a boiler body to form a fluidized bed, and fuel is jetted into the fluidized bed from a fuel nozzle to burn the fluidized bed. In the multi-layer boiler, a space forming plate is horizontally arranged at a position directly above the ejection port at the tip of the fuel nozzle, and when the fluidization of the bed material is stopped, the ejection port of the fuel nozzle is controlled by the repose angle of the bed material. It is characterized in that the surrounding space is formed in a mortar shape below the space forming plate.

Further, the space forming plate may be formed in a pyramid shape which is tapered upward.

[0017]

Therefore, in the present invention, when the fluidization of the bed material is stopped, a space like a mortar is formed below the space forming plate due to the angle of repose of the bed material, and the ejection port of the fuel nozzle is surrounded by the space. Therefore, the bed material is prevented from entering the ejection port of the fuel nozzle.

Further, in the case where the space forming plate is formed in the shape of a cone which tapers upward, the load of the bed member applied to the upper side of the space forming plate is reduced when the fluidization of the bed member is stopped. .

[0019]

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

FIG. 1 shows an embodiment of the present invention, in which a disk-shaped space is formed at a position just above an ejection port 16 at the tip of a fuel nozzle 3 having the same structure as the fuel nozzle 3 shown in FIG. The plate 21 is arranged horizontally, and the bed material 6
When the fluidization is stopped, the space 24 surrounding the ejection port 16 of the fuel nozzle 3 is formed below the space forming plate 21 in a mortar shape due to the angle of repose of the bed material 6. .

The space forming plate 21 is suspended and supported by the stay 22 and the like from the heat transfer tube 9 and the like shown in FIG.

In the fluidized bed provided with the space forming plate 21 as described above, the fuel 20 ejected from the tip of the fuel nozzle 3 and the air ejected from the tip of the fuel-dispersed air supply pipe 17 are stopped to form the bed material 6 of the fluidized bed. In the stationary state, the weight of the bed material 6 above the space forming plate 21 is equal to the weight of the space forming plate 21.
And a mortar-shaped space 24 is formed below the space forming plate 21 at an inclination 23 according to the angle of repose determined by the type of the bed material 6.

If the position of the ejection port 16 of the fuel nozzle 3 is arranged in this space 24, the operation of the boiler is stopped and the fuel 20 in the fuel nozzle 3 is recovered to recover the fuel. When the inside of the nozzle 3 is emptied, the bed material 6 does not fall down and does not enter the fuel nozzle 3 from the ejection port 16, so that the fuel nozzle 3 is not clogged with the bed material 6 of the fluidized bed.

Therefore, according to the above embodiment, the bed material 6
Even if the fluidization of No. 2 is stopped, the angle of repose of the bed material 6 forms a mortar-shaped space 24 below the space forming plate 21,
Since the ejection port 16 of the fuel nozzle 3 is surrounded by the space 24, the bed material 6 for the ejection port 16 of the fuel nozzle 3 is surrounded.
Can be prevented, and the fuel nozzle 3 can be reliably prevented from being clogged with the bed material 6.

As an additional effect, if the space forming plate 21 is arranged at a position just above the jet port 16 at the tip of the fuel nozzle 3 as described above, it is jetted from the tip of the fuel nozzle 3 during operation of the boiler body 1. Since the fuel 20 is well diffused to the surroundings by the space forming plate 21, the dispersibility of the fuel 20 is also improved.

FIG. 2 is a cross-sectional view of another embodiment of the present invention, which is an example in which the fuel nozzle 3 is arranged laterally.
Also in this case, when the fuel 20 ejected from the tip of the fuel nozzle 3 and the air ejected from the tip of the fuel dispersion air supply pipe 17 are stopped and the fluidization of the bed material 6 is stopped, the bed above the space forming plate 21 is stopped. The weight of the material 6 is supported by the space forming plate 21, and below the space forming plate 21, a mortar-shaped space 24 is formed with an inclination 23 according to the angle of repose determined by the type of the bed material 6, so that fluidization is achieved. The bed material 6 that has stopped does not enter the fuel nozzle 3 from the ejection port 16 and the fuel nozzle 3 is prevented from being clogged with the bed material 6 of the fluidized bed.

FIG. 3 shows still another embodiment of the present invention, in which the space forming plate 21 is formed in the shape of a cone that tapers upward, and in this way, the bed material 6 is fluidized. It is possible to reduce the load of the bed material 6 applied to the upper side of the space forming plate 21 when stopping.

The fuel supply device for a fluidized bed boiler of the present invention is not limited to the above-mentioned embodiment, but can be applied to fluidized bed boilers other than the pressurized fluidized bed boiler.
Of course, various changes can be made without departing from the scope of the present invention.

[0029]

According to the fuel supply device for a fluidized bed boiler of the present invention described above, various excellent effects as described below can be obtained.

(I) Even when the fluidization of the bed material is stopped, the angle of repose of the bed material forms a mortar-like space below the space forming plate, and the space surrounds the jet nozzle of the fuel nozzle. Therefore, it is possible to prevent the bed material from entering the ejection port of the fuel nozzle, and to reliably prevent the fuel nozzle from being clogged with the bed material.

(II) When the space forming plate is formed in the shape of a cone that tapers upward, the load of the bed member applied to the upper side of the space forming plate is reduced when the fluidization of the bed member is stopped. You can

[Brief description of drawings]

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

FIG. 2 is a sectional view showing another embodiment of the present invention.

FIG. 3 is a sectional view showing still another embodiment of the present invention.

FIG. 4 is a sectional view showing an example of a pressurized fluidized bed boiler.

FIG. 5 is a cross-sectional view showing a conventional example.

FIG. 6 is a cross-sectional view showing another conventional example.

[Explanation of symbols]

 1 Boiler Main Body 3 Fuel Nozzle 6 Bed Material 16 Jet Port 21 Space Forming Plate 24 Space

Claims (2)

[Claims] 1. A fluidized bed boiler in which a bed material is fluidized by combustion air in a boiler main body to form a fluidized bed, and fuel is jetted from a fuel nozzle into the fluidized bed to burn the fluidized bed boiler. The space forming plate is horizontally arranged at a position directly above the jet port, and the space surrounding the jet port of the fuel nozzle is defined by the angle of repose of the bed material when the fluidization of the bed material is stopped. A fuel supply device for a fluidized bed boiler, wherein the fuel supply device is configured to be formed in a mortar shape below the nozzle. 2. The fuel supply device for a fluidized bed boiler according to claim 1, wherein the space forming plate is formed in a cone shape that is tapered upward.