JPH0828815A - Diffuser device for fluidized bed boilder - Google Patents

Abstract

PURPOSE:To simply remove a bed material in a diffuser pipe without the need of hands and without stoppage of a fluidized bed boiler. CONSTITUTION:This diffuser device for fluidized bed boilers comprises a recess 22 formed on a bottom portion of a diffuser body 21 of a pressurized fluidized bed boiler 2, a dual pipe 25 composed of an inner pipe 23 and an outer pipe 24, of which tip ends are situated in the recess 22, a discharge pipe 26 connected to a base end of the inner pipe 23, and a gas conducting pipe 28 connected to a base end of the outer pipe 24 for permitting an air 6a' in a pressure vessel to be conducted therethrough. A bed material 5 falling on the diffuser body 21 is collected in the recess 22, and is fluidized by the air 6a' in the pressure vessel to be sucked and discharged by the inner pipe 23.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air diffuser for supplying air to a fluidized bed in a fluidized bed boiler.

[0002]

2. Description of the Related Art As an example of a fluidized bed boiler, an example in which a pressure type fluidized bed boiler is used in a power generation system will be described with reference to FIG. A bed boiler 2 is provided, and a plurality of air diffusers 3a are arranged below the fluidized bed boiler 2 at a required interval in a direction perpendicular to the plane of the drawing to form an air diffuser body 3.

Coal 4, desulfurization material such as limestone, or sand is supplied to the upper part of the air diffuser body 3, and bed material 5 in which combustion ash from combustion of the coal 4, limestone, sand or the like is mixed.
To form a fluidized bed. Pressurized air 6a from the compressor 6 is supplied into the pressure vessel 1, and further air 6a 'in the pressure vessel is supplied from below to each air diffusing pipe 3a of the air diffusing body 3 and jetted upward, so that coal 4 is in a fluidized bed. It is agitated with air in the interior of the heat exchanger and efficiently burns to heat the water in the heat transfer tube 7 to generate steam. Further, the ash generated by the combustion and a part of the bed material 5 are adapted to fall downward from between the air diffusers 3a and be taken out.

The steam generated in the heat transfer tube 7 drives the steam turbine 8 to generate power by the steam turbine generator 9, and the steam driving the steam turbine 8 is condensed by the condenser 10.
The heat is transferred to the heat transfer tube 7 again via the heat exchanger 11.

The combustion exhaust gas obtained by heating the water in the heat transfer tube 7 is dust-removed by the dust collector 12 and then drives the gas turbine 13. The gas turbine 13 drives the above-described compressor 6 and also drives the gas turbine generator 14 with surplus power to be discharged from the stack 16 through the denitration device 15 and the heat exchanger 11.

The load of the fluidized bed boiler 2 is adjusted by changing the bed height of the fluidized bed and changing the amount (heat transfer area) of the heat transfer tubes 7 in the fluidized bed.

That is, when the load of the fluidized bed boiler 2 is reduced, the pressure of the bed material storage tank 17 is reduced and the bed material 5 is transferred from the fluidized bed boiler 2 to the bed material storage tank 17.
Is sucked out to lower the bed height of the fluidized bed, and the amount of heat exchange is reduced together with the heat transfer area in the fluidized bed to reduce the amount of steam generated.

On the contrary, when the load of the fluidized bed boiler 2 is increased, the opening degree of the high pressure air valve 18 is increased and the amount of the bed material 5 which is air-conveyed from the bed material storage tank 17 to the fluidized bed boiler 2 is increased. Increase the height of the fluidized bed to increase the amount of heat exchange along with the heat transfer area in the fluidized bed to increase the amount of steam generated.

Air diffuser 3a constituting the air diffuser body 3 described above.
5 is a hollow cavity that extends horizontally as shown in FIG. 5. A large number of air diffuser nozzles 19 are provided on the upper surface of the air diffuser pipe 3a so as to project upward. The aeration nozzle 19 has a cylindrical shape,
As shown in FIG. 6, a large number of air diffusion holes 20 for uniformly dispersing air in the layer are formed on the cylindrical side surface of the air diffusion nozzle 19. Then, the air 6a 'in the pressure vessel supplied to the air diffusing pipe 3a is ejected from the air diffusing holes 20 of the air diffusing nozzle 19 into the fluidized bed.

Further, in FIGS. 7 and 8, not the air diffuser 3a,
An example of a normal pressure fluidized bed boiler 30 including an air diffuser main body 31 including an air diffuser plate 31a is shown.
An air diffuser plate 31 having an air introducing chamber 31b is provided in the lower portion of the air introducing chamber 31b. The combustion air 32a pressurized from a combustion air pipe 32 connected to the side of the air diffuser plate 31a is supplied to the air introducing chamber 31.
b, the combustion air 32a is jetted into the fluidized bed from the diffuser nozzle 19 provided on the upper side of the diffuser plate 31a, as shown in FIGS. Reference numeral 5a is a bed material withdrawal pipe provided at some places of the air diffuser plate 31a.

Further, in the pressurized fluidized bed boiler 2 shown in FIG. 4, a diffuser plate 31a shown in FIGS. 7 and 8 is provided in addition to the system having the diffuser body 3 consisting of the diffuser pipe 3a as shown in the figure. There is also an air diffuser body 31 composed of the above, and the fluidized bed boiler 30 shown in FIGS.
Also, in the air diffuser main body 3 including the illustrated air diffuser plate 31a
In addition to the system including 1, the air diffuser main body 3 including the air diffuser 3a shown in FIG. 4 is provided.

[0012]

However, when the operation of the fluidized bed boilers 2 and 30 is stopped, the inside of the pressure vessel ejected from the air diffuser holes 20 of the air diffuser nozzles 19 provided in the air diffuser bodies 3 and 31. The ejection of the air 6a 'and the combustion air 32a is stopped. Since the bed material 5 has a particle size of about 1 mm or less, when the jetting of the pressure vessel air 6a ′ and the combustion air 32a from the diffuser holes 20 is stopped by stopping the operation of the fluidized bed boilers 2 and 30 as described above, the fluidized bed is 6 through the air diffuser holes 20 in FIG. 6 into the air diffuser 3a in FIGS. 4 and 5 and the air introducing chamber 31a below the diffuser plate 31a in FIG.
The bed material 5 may accumulate in the air diffuser bodies 3 and 31. When the bed material 5 accumulates and accumulates in the air diffuser bodies 3 and 31, the uniform air flow in the air diffuser pipe 3a and the air introducing chamber 31b cannot be performed, so that the bed material 5 accumulates in the air diffuser pipe 3a and the air introducing chamber 31b. It is necessary to remove the remaining bed material 5.

Conventionally, the bed material 5 stored in the air diffuser 3a and in the air introducing chamber 31b below the air diffuser plate 31a is manually removed. Therefore, first, the bed material in the fluidized bed boilers 2, 30 is to be removed. After extracting 5 into the bed material storage tank 17, the operation of the fluidized bed boilers 2 and 30 is stopped and the fluidized bed boiler 2 and 30 are stopped.
After cooling 30, in the case of the pressurized fluidized bed boiler 2, an operator enters the pressure vessel 1 to remove the bed material 5 from inside the air diffuser bodies 3 and 31.

Therefore, in the conventional bed material removing work from the air diffuser bodies 3 and 31, it is necessary to first remove the bed material 5 from the fluidized bed boilers 2 and 30, and the operation of the fluidized bed boilers 2 and 30 is performed. It took time to stop and cool, and the work itself of removing the bed material 5 from the air diffuser bodies 3 and 31 was also a difficult work because the environment was bad.

The present invention solves these conventional problems,
An object of the present invention is to provide an air diffuser for a fluidized bed boiler that can easily remove the bed material that has entered the air diffuser main body without stopping the operation of the fluidized bed boiler without requiring any manpower. To do.

[0016]

The invention of claim 1 comprises a recess formed in the bottom of the diffuser body of a pressurization type fluidized bed boiler, and an inner pipe and an outer pipe having their ends facing the recess. A diffuser for a fluidized bed boiler, comprising a double pipe, a discharge pipe connected to the base end of the inner pipe, and an air guide pipe connected to the base end of the outer pipe to guide air in the pressure vessel. Qi device.

According to a second aspect of the present invention, a recess is formed in the bottom of the air diffuser body of the fluidized bed boiler at normal pressure, a double pipe composed of an inner pipe and an outer pipe whose front ends face the recess, and An air diffuser for a fluidized bed boiler, comprising an exhaust pipe connected to the base end of an inner pipe, and a pressurized air supply pipe connected to the outer pipe base end for introducing pressurized air. It is related to.

[0018]

According to the invention of claim 1, the bed material that has entered the diffuser body flows into the recess formed in the bottom of the diffuser body, and the bed material stored in the recess has a pressure difference between the inside of the diffuser body and the atmosphere. Is sucked and discharged to the outside through the inner pipe and the discharge pipe of the double pipe. Also, since the bed material in the recess is fluidized by the air inside the pressure vessel that is guided from the inside of the pressure vessel and jetted from the tip of the outer tube of the double pipe, the bed material is easily sucked from the outer tube, and the bed material is Bed material does not accumulate.

According to the second aspect of the invention, the bed material that has entered the air diffuser body flows into the recess formed in the bottom of the air diffuser body,
The bed material stored in the recess is sucked and discharged to the outside through the inner pipe and the discharge pipe of the double pipe due to the pressure difference between the inside of the diffuser body and the atmosphere. Further, since the bed material in the recess is fluidized by the pressurized air ejected from the tip of the outer tube of the double tube, the bed material is likely to be sucked from the outer tube and the bed material may accumulate in the air diffuser body. Absent.

[0020]

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

FIG. 1 is a vertical cross-sectional view showing an essential part of an embodiment of the invention of claim 1, in which a fluidized bed boiler 2 is provided in a pressure vessel 1 having a pressurized atmosphere inside. An air diffuser body 21 including an air diffuser 21a is attached to the lower part of the fluidized bed boiler 2. On the upper surface of the air diffusing body 21, the air diffusing nozzle 1 similar to the conventional one described with reference to FIGS.
9 is projected upward, and air 6a 'in the pressure vessel is jetted into the fluidized bed.

At the bottom near the tip of the air diffuser 21a, a recess 22 is formed which is recessed downward. In this recess 22, a double pipe 25 consisting of an inner pipe 23 and an outer pipe 24 is formed. The tip is facing.

The tip of the inner pipe 23 projects slightly toward the recess 22 than the tip of the outer pipe 24, and the base end of the inner pipe 23 is connected to the tip of the discharge pipe 26. A discharge valve 27 is attached to the discharge pipe 26, and the base end side of the discharge pipe 26 is guided to the atmosphere or the exhaust gas duct via a cyclone, a filter, etc. not shown.

The base end of the outer pipe 24 is connected to the tip of the air guiding pipe 28, and the base end side of the air guiding pipe 28 is connected to the inside of the pressure vessel 1 via the air guiding valve 29.

Pressurized air 6a from the compressor 6 of FIG.
Is first supplied into the pressure vessel 1, and then the air 6a 'in the pressure vessel is introduced into the air diffusing tube 3a and ejected from the air diffusing nozzle 19, so that the pressure of the air in the air diffusing tube 3a is increased. Is lower than the pressure of the air in the pressure vessel 1 due to the draft loss. Therefore, when the air guiding valve 29 of the air guiding tube 28 in FIG. 1 is opened, the air 6a ′ in the pressure vessel is discharged from the outer tube 24 of the double tube 25. It is designed to be ejected into the recess 22.

Next, the operation of the apparatus shown in FIG. 1 will be described.

By operating the fluidized bed boiler 2, the diffuser nozzle 1
The bed material 5 that has entered the diffuser pipe 21a through the diffuser holes 20 of 9 drops to the bottom of the diffuser pipe 21a and receives the force of the flow of the air 6a 'in the pressure vessel inside the diffuser pipe 21a to receive the diffuser pipe 21a.
It moves to the tip side of a and enters the recess 22.

When the discharge valve 27 of the discharge pipe 26 is opened and the discharge pipe 26 is communicated with the atmosphere, the bed material 5 stored in the recess 22 is caused by the pressure difference between the diffuser pipe 21a and the atmosphere to cause the inner pipe 2
3 is sucked inside, and is discharged to the outside through the discharge pipe 26. At this time, when the air guide valve 29 of the air guide pipe 28 is opened, the air 6a ′ in the pressure vessel comes to be blown into the recess 22 from the outer pipe 24 of the double pipe 25. Are diffused without being accumulated and are effectively sucked into the inner tube 23.

Therefore, according to the above, it is possible to discharge the bed material 5 contained in the air diffusing pipe 21a without stopping the operation of the fluidized bed boiler 2 and requiring no manpower. The bed material 5 stored in the recess 22 may be discharged constantly or as needed. The recess 22 formed at the bottom of the air diffusing tube 21a is not limited to the location near the tip of the air diffusing tube 21a, but may be formed at the bottom of the middle portion of the air diffusing tube 21a.

FIG. 2 is a vertical cross-sectional view showing the main part of another embodiment of the invention of claim 1, in which a diffuser plate 34a is provided at the bottom of the fluidized bed boiler 2 shown in the drawing. Below the air diffuser plate 34a, there is provided an air diffuser main body 34 in which an air introduction chamber 34b having a pressurized air introduction port 36 communicating with the inside of the pressure vessel 1 is formed in the lower central portion.

At the left and right lower positions of the air introducing chamber 34b of the air diffuser body 31, there are formed recesses 22 which are recessed downward, and the recesses 22 are formed by an inner pipe 23 and an outer pipe 24. The leading end of the double tube 25 is exposed. The tip of the inner pipe 23 slightly projects toward the recess 22 than the tip of the outer pipe 24, and the base end of the inner pipe 23 is connected to the tip of the discharge pipe 26. The base end of the outer pipe 24 is connected to the tip of the air guide pipe 28, and the base end side of the air guide pipe 28 is connected to the inside of the pressure vessel 1 via the air guide valve 29.

The embodiment shown in FIG. 2 differs from that shown in FIG. 1 in that the air diffuser 34a is used as the air diffuser body 34, but the bed material 5 stored in the recess 22 is discharged to the outside. Since the operation is exactly the same as that of the embodiment shown in FIG.
A duplicate description will be omitted.

FIG. 3 is a vertical cross-sectional view showing an essential part of an embodiment of the invention of claim 2, wherein the fluidized bed boiler 30 shown is a normal pressure boiler without a pressure vessel, and the normal pressure fluidized bed is shown. An air diffuser 35a is provided in the lower portion of the boiler 30, and an air introducing chamber 35b for supplying the combustion air 32a from the combustion air pipe 32 is formed below the air diffuser 35a. A body 35 is provided. On the upper surface of the air diffuser plate 35a, the air diffuser nozzle 19 similar to the conventional one described with reference to FIGS.
Are projected upward, and high-pressure air is jetted into the fluidized bed.

A concave portion 22 is formed in the bottom of the air diffuser body 35 at a substantially central portion thereof. The concave portion 22 is formed in the concave portion 22. The concave portion 22 has an inner pipe 23 and an outer pipe 24. Is facing the tip.

The tip of the inner pipe 23 projects slightly toward the recess 22 than the tip of the outer pipe 24, and the base end of the inner pipe 23 is connected to the tip of the discharge pipe 26. A discharge valve 27 is attached to the discharge pipe 26, and the base end side of the discharge pipe 26 is guided to the atmosphere or the exhaust gas duct via a cyclone, a filter, etc. not shown.

The base end of the outer pipe 24 is connected to the tip of the pressurized air supply pipe 33, and the base end side of the pressurized air supply pipe 33 is provided with a combustion air pressure source or the like via an air guide valve 29. Compressed air 3
3a is connected to an air source. At this time, the pressure of the compressed air 33a supplied to the outer pipe 24 of the double pipe 25 is set to be higher than the pressure of the combustion air 32a supplied to the diffuser plate 31.

Next, the operation of the apparatus shown in FIG. 3 will be described.

The bed material 5 that has fallen from the diffuser holes 20 of the diffuser nozzle 19 into the diffuser plate 35a by the operation of the fluidized bed boiler 30 is collected in the recess 22, so that when the discharge valve 27 of the discharge pipe 26 is opened, Due to the pressure difference between the air diffuser body 35 and the atmosphere, the bed material 5 in the recess 22 is sucked into the inner pipe 23 and discharged to the outside through the discharge pipe 26.
At this time, if the air guiding valve 29 of the pressurized air supply pipe 33 is opened, the pressurized air 33a will be blown into the recess 22 from the outer pipe 24 of the double pipe 25. 5 is fluidized without being accumulated and is effectively sucked into the inner pipe 23.

Therefore, according to the above, the bed material 5 contained in the air diffuser body 35 can be discharged without stopping the operation of the fluidized bed boiler 30 and without requiring any manpower. In this case as well, the bed material 5 in the recess 22 may be discharged constantly or if necessary.

Further, in the normal pressure fluidized bed boiler 30 of FIG. 3, instead of the method of providing the diffuser body 35 by the diffuser plate 35a shown in the figure, the diffuser body consisting of the diffuser pipe 3a as shown in FIG. 3 may be provided, and in this case as well, the bed material 5 that has entered the air diffuser main body 3 and is stored in the concave portion 22 is made to flow while the pressurized air 33a from the pressurized air supply pipe 33 is caused to flow. As a matter of course, it is possible to easily suck and discharge to the outside by 26.

[0041]

According to the first aspect of the present invention, the bed material that has entered the diffuser body is collected in the concave portion without stopping the operation of the fluidized bed boiler and without requiring manpower. There is an effect that it can be easily and surely discharged to the outside in a short time while being fluidized and sucked from the discharge pipe.

According to the second aspect of the invention, the discharge pipe is fluidized by the pressurized air while the bed material contained in the diffusing pipe is fluidized without stopping the operation of the fluidized bed boiler and requiring no manpower. There is an effect that it can be sucked from and discharged to the outside easily and reliably in a short time.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view of a main part showing an embodiment of the invention of claim 1;

FIG. 2 is a vertical sectional view showing another embodiment of the invention of claim 1;

FIG. 3 is a vertical sectional view showing an embodiment of the invention of claim 2;

FIG. 4 is a system diagram of a power generation system using a conventional pressurized fluidized bed boiler.

5 is a front view showing an example of the air diffusing tube of FIG. 4. FIG.

FIG. 6 is a front view of an air diffusing nozzle.

FIG. 7 is a vertical cross-sectional view showing an example of a conventional fluidized bed boiler at normal pressure.

FIG. 8 is a view on arrow VIII-VIII in FIG. 7.

[Explanation of symbols]

 1 Pressure Vessel 2 Pressurized Fluidized Bed Boiler 6a 'Pressure Vessel Inner Air 21 Diffuser Main Body 22 Recessed portion 23 Inner Tube 24 Outer Tube 25 Double Pipe 26 Discharge Pipe 28 Air Conductor 30 Normal Pressure Fluidized Bed Boiler 33 Pressurized Air Supply Tube 33a Pressurized air 34 Air diffuser body 35 Air diffuser body

Claims (2)

[Claims] 1. A recess formed in the bottom of an air diffuser body of a pressurized fluidized bed boiler, a double pipe composed of an inner pipe and an outer pipe whose front ends face the recess, and a base end of the inner pipe. An air diffuser for a fluidized bed boiler, comprising: a discharge pipe connected to the outer pipe; and an air guide pipe connected to the base end of the outer pipe to guide air in the pressure vessel. 2. A recess formed in the bottom of the air diffusing body of a fluidized bed boiler at normal pressure, a double pipe composed of an inner pipe and an outer pipe whose front ends face the recess, and a base end of the inner pipe. An air diffuser for a fluidized bed boiler, comprising: a discharge pipe connected to the outer pipe; and a pressurized air supply pipe connected to the proximal end of the outer pipe to introduce pressurized air.