JPH1089620A - Bed material treating device in pressurized fluidized bed type boiler - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent powdered bed material from being returned back to a bed material storing container when the bed material is extracted from a main body of a boiler during a tripping of a gas turbine. SOLUTION: A pressurized fluidized bed boiler 1 is constructed such that bed material 10 extracted from a main body 3 of a boiler is fed to a lock hopper 42 installed above a bed material storing container 5 through an ash discharging pipe 28, a bed material extracting pipe 33, a bed material feeding pipe 38 and bed material returning pipes 41, 47 and further the material can be returned from the lock hopper 42 to the bed material storing container 5. In this boiler 1, a dust collecting hopper 45 is installed above the lock hopper 42, the end part of the bed material returning pipe 41 at the inlet side of the dust collecting hopper 45 is connected to an outer circumference of the dust collecting hopper 45 in a tangential direction there to, the lower end of the dust collecting hopper 45 and the upper end of the lock hopper 42 are connected by the bed material returning pipe 47, and the lower end of the lock hopper 42 and the upper end of the bed material storing container 5 are connected by the bed material returning pipe 44.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bed material treatment apparatus for a pressurized fluidized bed boiler, and more particularly to a bed material treatment for a pressurized fluidized bed boiler in which powdered bed material is not returned to a bed material storage container. It concerns the device.

[0002]

2. Description of the Related Art In recent years, pressurized fluidized bed boilers have been developed for effective use of energy.

[0003] An example of a conventional pressurized fluidized-bed boiler is shown in Fig. 3, in which 1 is a pressurized fluidized-bed boiler. The pressurized fluidized bed boiler 1 includes a pressure vessel 2,
The boiler body 3, the cyclone 4, and the bed material storage container 5 are stored in the pressure container 2.

[0004] The boiler body 3 is surrounded by a furnace wall formed by connecting heat transfer tubes and fins, and a furnace 6 is formed inside the furnace. A heat transfer device such as an evaporator and a superheater is provided in the furnace 6. Section 7 is housed, and the pressure vessel 2
Further, a fuel injection nozzle 8 that injects fuel into the furnace 6 through the furnace wall of the boiler body 3 is provided.

[0005] In the vicinity of the upper end of the ash extraction hopper 9 provided at the lower part of the furnace 6, the bed material 1 housed in the furnace 6 is provided.
Compressed air AC fluidizing the pressure 0 from the pressure vessel 2 to the furnace 6
In order to blow air into the inside, a plurality of sets of diffuser tubes 11 having a large number of ejection holes are arranged at a predetermined pitch in a direction orthogonal to the paper surface of FIG. The bed material 10 is a mixture of a desulfurizing agent, sand and the like.

At the upper end of the boiler body 3, a bed material 10 is provided.
The manifold 12 for introducing the combustion gas GB generated by the combustion of the fuel in the furnace 6 by the heat of the exhaust gas as the exhaust gas GE is provided so as to extend upward.

An exhaust pipe 13 extending in the horizontal direction is connected near the upper end of the manifold 12.
Is connected to the outer periphery of the cyclone 4 in the tangential direction of the outer periphery of the cyclone 4.

An exhaust gas pipe 14 is connected to the top of the cyclone 4. The exhaust gas pipe 14 extends through the pressure vessel 2 to the outside, and its tip is connected to a gas turbine 15. Thus, the gas turbine 15 is connected to the manifold 12.
It can be driven by exhaust gas GE supplied from the exhaust gas pipe 13, the cyclone 4, and the exhaust gas pipe 14.

The gas turbine 15 can drive a generator 16 and a compressor 17 connected to the gas turbine 15, and the compressed air AC1 generated by the compressor 17 is compressed air. It can be introduced into the pressure vessel 2 via a feed pipe 18.

An L valve 20 is connected to a lower part of the bed material storage container 5 via a bed material take-out pipe 19.
At the rear end of the L valve 20, a rear end is connected to the pressure vessel 2 and a compressed air injection pipe 22 provided with an injection valve 21 in the middle.

A bed member 1 is provided at the front end of the L valve 20.
Bed material injection pipe 23 for introducing 0 into the boiler body 3
Is connected to the bottom end of the boiler main body 3.

The lower end of the bed material extraction pipe 24 is connected to the lower side of the boiler main body 3, and the tip of the bed material extraction pipe 24 is connected to the upper end of the bed material storage container 5.
An internal pressure discharge pipe 27 provided with an internal pressure discharge valve 26 in the middle is connected near the upper part of the bed material storage container 5.

An L valve 29 is connected to the lower end of the ash pipe 28 connected to the lower part of the ash hopper 9, and the L valve 2
9 is provided with an injection valve 30 in the middle of the compressed air A
A compressed air injection pipe 31 for feeding C2 is connected.

An upper end of a lock hopper 34 is connected to an end of the L valve 29 via a bed material extraction pipe 33 provided with an extraction valve 32 in the middle, and an extraction valve 35 is connected to a lower end of the lock hopper 34. The provided bed material extraction pipe 36 is connected.

At the lower end of the bed material extraction pipe 36, the bed material 10 descending from the lock hopper 34 through the bed material extraction pipe 36 is supplied with compressed air AC3 from a blower 37.
A bed material feed pipe 38 for feeding is connected,
The bed material supply pipe 38 is connected to a bed material hopper (not shown).

A return valve 40 is provided in the middle of the bed material feeding pipe 38 at a position upstream of the connection portion of the discharge valve 39 in the bed material transport direction.
Is connected to the upper end of a lock hopper 42 disposed above the pressure vessel 2.

The lower end of the lock hopper 42 is connected to a bed material return pipe 44 provided with a return valve 43 in the middle thereof. It is connected to the upper end of the bed material storage container 5.

When the pressurized fluidized bed boiler 1 is operated, a predetermined amount of bed material 10 is stored in the boiler body 3 and the compressed air AC supplied to the pressure vessel 2 is supplied.
1 is introduced into the boiler main body 3 through the air diffuser 11, and the bed material 10 is fluidized in the boiler main body 3.

The fuel such as coal slurry injected into the boiler main body 3 from the fuel injection nozzle 8 is burned by the heat of the bed material 10 or the like to generate a combustion gas GB.
B heats the fluid in the heat transfer section 7 and the heat transfer tube in the furnace wall of the furnace 6 while ascending in the furnace 6 to generate steam, and passes through the furnace 6 as manifold GE as exhaust gas GE from the boiler body 3. It is discharged to 12.

Exhaust gas GE discharged to the manifold 12
Is introduced into the cyclone 4 from the manifold 12 through the exhaust gas pipe 13, the coal combustion ash and unburned coal particles are separated by the cyclone 4, introduced into the gas turbine 15 through the exhaust gas pipe 13, and discharged by the exhaust gas GE. Turbine 15
Is driven.

When the gas turbine 15 is driven, the generator 16 is driven to generate electric power, and the compressor 17 is driven.
Is driven, and the compressed air AC1 generated by the compressor 17 is
It is introduced into the pressure vessel 2 via the compressed air supply pipe 18.

The steam generated by the boiler body 3 is used to drive a steam turbine (not shown).

When the boiler load fluctuates, it is necessary to change the layer height of the bed material 10 in the boiler main body 3.

That is, when the boiler load increases, the injection valve 21 is opened. Then, the compressed air AC1 in the pressure vessel 2 passes through the compressed air injection pipe 22 and the L valve 2
0, and is introduced into the boiler main body 3 from the L valve 20 through the bed material injection pipe 23. Therefore, the bed material 10 in the bed material storage container 5 is
, And is introduced into the boiler main body 3 through the L valve 20 and the bed material injection pipe 23. As a result, the layer height of the bed material 10 in the boiler main body 3 increases.

When the boiler load is reduced, the internal pressure discharge valve 26 is opened to reduce the pressure of the bed material storage container 5. Then, due to the pressure difference between the inside of the boiler body 3 and the inside of the bed material storage container 5, the bed material 10 in the boiler body 3 is withdrawn from the bed material extraction pipe 24 into the bed material storage container 5, and the boiler body 3 The bed height of the bed material 10 in the interior is reduced.

In the pressurized fluidized-bed boiler described above, when the gas turbine 15 trips for any reason, the supply of the fuel and the compressed air AC1 is stopped, and the fluidized bed is not formed. Large amount of bed material 10
Will accumulate. Therefore, when the operation is restarted after the trip occurs, it is necessary to extract the bed material 10 deposited on the bottom inside the boiler main body 3 and return it to the bed material storage container 5 once.

That is, when the gas turbine 15 trips, the injection valve 30 and the extraction valve 32 are opened. Then, the compressed air AC2 that has passed through the compressed air injection pipe 31 is
The bed material is fed from the L valve 29 to the bed material extraction pipe 33 side.

For this reason, the bed material 10 in the boiler main body 3
Is dropped from between the air diffusers 11 and stored in the lock hopper 34 through the ash hopper 9, the ash pipe 28, the L valve 29, and the bed material extraction pipe 33.

A predetermined amount of the bed material 10 is
Then, the valves 30 and 32 are closed, the discharge valve 39 is kept closed, the extraction valve 35 and the return valve 40 are opened, and the blower 37 is driven. Therefore, the bed material 10 in the lock hopper 34 is moved from the lock hopper 34 to the bed material feeding pipe 38.
The bed material is fed into the bed material feed pipe 38 by the compressed air AC3 from the blower 37, and the bed material return pipe 41
Is fed into the lock hopper 42 through

When the bed material 10 is fed from the lock hopper 34 to the lock hopper 42, the valves 35 and 40 are closed, and the return valve 43 is opened. Therefore, the bed material 10 in the lock hopper 42 is returned to the bed material storage container 5 through the bed material return pipe 44.

The opening and closing of each valve during operation is closed except for those specifically described.

[0032]

In the pressurized fluidized bed boiler 1 described above, when the bed material 10 is pressure-fed from the bed material feed pipe 38 to the lock hopper 42 via the bed material return pipe 41, the bed material 10 Part of the powder is powdered by friction
μm or less), and powdered particles increase in the bed material 10 supplied to the boiler body 3 at the next startup of the pressurized fluidized-bed boiler 1. Therefore, when the pressurized fluidized-bed boiler 1 is started or the boiler load changes, the powdered particles of the bed material 10 are accompanied by the exhaust gas GE as fly ash and are carried out of the boiler main body 3, and as a result, the cyclone 4 Clogging or dust concentration increases at the inlet of the gas turbine 15.

Therefore, when the pressurized fluidized bed boiler 1 is operated, the load change rate of the boiler is made as small as possible so that fine particles are not entrained outside the boiler body 3 as fly ash.
Operational restrictions will also be required.

Further, since a part of the bed material 10 is carried out of the boiler main body 3 as fly ash, the amount of the bed material 10 that can be used is reduced, and as a result, a necessary amount of the bed material 10 is stored. Needs to increase the capacity of the bed material storage container 5.

In view of the above-mentioned circumstances, the present invention prevents the powdered bed material from being mixed as much as possible into the bed material which is extracted from the boiler body and returned to the bed material storage tank through the lock hopper when the gas turbine trips. The purpose is to make it.

[0036]

SUMMARY OF THE INVENTION According to the present invention, there is provided a pressurizing apparatus wherein a bed material injected into a boiler main body from a bed material storage container is extracted from a lower portion of the boiler main body and returned to the bed material storage container via a pipe. A fluidized-bed boiler, wherein a dust collection hopper is provided in a middle part of the pipeline so as to be located above the bed material storage container, and a dust collection hopper inlet side end of the pipeline is provided with a dust collection hopper. A lock hopper is disposed near the upper end of the dust collecting hopper so as to face tangentially to the outer periphery of the dust collecting hopper, and a lock hopper is disposed below the dust collecting hopper so as to be located above the bed material storage container. The vicinity of the lower portion of the dust hopper, the vicinity of the upper portion of the lock hopper, the vicinity of the lower portion of the lock hopper, and the vicinity of the upper portion of the bed material storage container are respectively connected.

Further, in the present invention, a line for supplying compressed air may be connected to the upstream side of the dust collecting hopper inlet side of the pipeline in the bed material feeding direction.

According to the present invention, by introducing the bed material in the tangential direction of the dust collecting hopper, the powdered bed material does not return into the boiler main body when the pressurized fluidized bed boiler is restarted. As a result, fly ash discharged from the boiler body is reduced, and as a result, clogging of the cyclone and an increase in dust concentration at the inlet of the gas turbine can be prevented.

Further, since it is not necessary to reduce the load change rate of the boiler, there is no need to limit the operation, and furthermore, it is possible to prevent the bed material from being powdered when introduced into the dust collecting hopper. Further, the capacity of the bed material storage container can be reduced.

Further, a line for supplying compressed air is connected upstream of the dust collection hopper inlet side connection portion of the pipe in the bed material feeding direction, so that the degree of powdering of the bed material can be reduced. Optimum dust collection efficiency can be obtained.

[0041]

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

FIGS. 1 and 2 show an embodiment of the present invention. In FIG. 1, the same components as those shown in FIG. 3 are denoted by the same reference numerals.

In this embodiment, a cyclone type dust collecting hopper 45 is disposed above the lock hopper 42, and the lower end of the dust collecting hopper 45 and the upper end of the lock hopper 42 are halfway. The section is connected by a bed material return pipe 47 having a return valve 46.

Further, the dust collecting hopper 45 of the bed material return pipe 41
As shown in FIG. 2, the inlet-side tip is connected so as to be tangential to the outer periphery of the dust-collecting hopper 45, and near the inlet-side end of the dust-collecting hopper 45 of the bed material return pipe 41, in the middle. A compressed air supply pipe 49 provided with a supply valve 48 is connected so that compressed air AC4 can be supplied to the bed material return pipe 41. Further, at the top of the dust collection hopper 45, an exhaust valve 50 is provided halfway. The exhaust pipe 51 provided with is connected.

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

The bed material 10 in the boiler body 3 due to the normal operation of the pressurized fluidized-bed boiler 1 and a change in the boiler load.
The adjustment of the layer height is the same as in the conventional case shown in FIG.

When the gas turbine 15 trips, the bed material 10 in the boiler main body 3 is fed through the bed material feed pipe 38 and the bed material return pipe 41 in the same manner as in the conventional case shown in FIG. Is done.

The bed material 10 that has been pressure-fed through the bed material feed pipe 38 and the bed material return pipe 41 is introduced into the dust collecting hopper 45 in the present embodiment. in this case,
By reducing the amount of the compressed air AC3 sent by the blower 37 and introduced into the dust collection hopper 45, the dust collection hopper 45 acts as a cyclone with low dust removal efficiency,
The fine particles of the bed material 10 powdered during the pressure feeding are sent from the dust collecting hopper 45 to the subsequent process through the exhaust pipe 51 together with the air, and the bed material 10 in a relatively large particle state is separated into the dust collecting hopper 45. And is introduced into the lock hopper 42 through the bed material return pipe 47. At this time, the valves 50 and 46 are open near the dust collection hopper 45, and the valves 48 and 46 are open.
43 is closed.

A predetermined amount of the bed material 10 is supplied to the lock hopper 42.
Is stored, the valves 46 and 50 are closed, and the return valve 43 is opened. Then, the bed material 10 in the lock hopper 42 is
Is returned from the bed material return pipe 44 to the bed material storage container 5 in the same manner as in the conventional case shown in FIG.

When collecting the bed material 10 in the dust collecting hopper 45 when the bed material 10 is not powdered much, the return valve 46 is closed, and the supply valve 48 and the exhaust valve 50 are opened. Therefore, the bed material return pipe 4 is inserted into the dust collection hopper 45.
In addition to the compressed air AC3 accompanied by the bed material 10 from 1, compressed air AC4 from a compressed air supply pipe 49 is introduced into the dust collection hopper 45 from the hopper tangential direction. And the dust collection efficiency increases. Therefore, the amount of the bed material 10 sent to the subsequent process through the exhaust pipe 51 together with the air is reduced, and most of the bed material 10 can be collected by the dust collection hopper 45.

The compressed air AC accompanying the bed material 10
Since 3 and the like are introduced into the dust collecting hopper 45 from the hopper tangential direction, powdering of the bed material 10 is prevented.

According to the embodiment of the present invention, when the pressurized fluidized bed boiler 1 is restarted, the amount of the bed material 10 powdered to a size of 300 μm or less entering the boiler main body 3 is reduced. Reduced fly ash and, consequently,
There is no clogging of the cyclone 4 and no increase in the dust concentration at the inlet of the gas turbine 15.

Further, it is not necessary to reduce the load change rate of the boiler so that the bed material 10 is not entrained outside the boiler body 3 as fly ash when the load of the pressurized fluidized bed boiler 1 rises. No restriction is required, and the powdered bed material 10 does not return to the bed material storage container 5, so that the capacity of the bed material storage container 5 can be reduced.

Further, by appropriately adjusting the opening degree of the supply valve 48 to adjust the flow rate of the compressed air AC4 introduced into the dust collecting hopper 45, the dust collecting hopper can be adjusted according to the degree of powdering of the bed material 10. The dust collection efficiency of 45 can be appropriately adjusted.

It should be noted that the embodiment of the present invention is not limited to the above-described embodiment, and it goes without saying that various changes can be made without departing from the spirit of the present invention.

[0056]

According to the bed material treatment apparatus for a pressurized fluidized-bed boiler of the present invention, in the case of the first aspect, i) the powder is pulverized when the pressurized fluidized-bed boiler is restarted or when the load is increased. Since the bed material is not introduced into the boiler main body, fly ash discharged from the boiler main body is reduced, and as a result, it is possible to prevent clogging of the cyclone and increase of dust concentration at the inlet of the gas turbine. .

Ii) It is not necessary to reduce the load change rate of the boiler so that the bed material is not entrained outside the boiler as fly ash during operation of the pressurized fluidized-bed boiler, so that there is no need to limit the operation. .

Iii) Since the powdered bed material does not return to the bed material storage container, the capacity of the container can be reduced as a whole.

Iv) Powdering of the bed material when introduced into the dust collecting hopper can be prevented. In the case of the second aspect, by adjusting the flow rate of the compressed air in addition to the effect of the first aspect, the optimal dust collection efficiency corresponding to the degree of powdering of the bed material is obtained. Can be obtained.

[Brief description of the drawings]

FIG. 1 is an overall schematic diagram showing an example of an embodiment of a bed material processing apparatus in a pressurized fluidized-bed boiler of the present invention.

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

FIG. 3 is an overall schematic diagram showing an example of a bed material processing apparatus in a conventional pressurized fluidized bed boiler.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Pressurized fluidized-bed boiler 3 Boiler main body 5 Bed material storage container 10 Bed material 28 Ash ash pipe (pipe) 33 Bed bleed pipe (pipe) 36 Bed bleed pipe (pipe) 38 Bed material feed pipe ( 41) Bed material return pipe (pipe) 42 Lock hopper 44 Bed material return pipe (pipe) 45 Dust collection hopper 47 Bed material return pipe (pipe) 49 Compressed air supply pipe (line)

Claims (2)

[Claims] 1. A pressurized fluidized-bed boiler capable of extracting bed material injected from a bed material storage container into a boiler main body from a lower portion of the boiler main body and returning the bed material to the bed material storage container via a pipeline, A dust collection hopper is provided in the middle of the pipe so as to be located above the bed material storage container, and a dust collection hopper inlet end of the pipe is disposed near the upper end of the dust collection hopper. A lock hopper is disposed below the dust collecting hopper so as to be located above the bed material storage container, and a lock hopper near the lower portion of the dust collecting hopper is provided by the conduit. A bed material processing apparatus for a pressurized fluidized-bed boiler, wherein the vicinity of the upper portion of the bed and the vicinity of the lower portion of the lock hopper and the vicinity of the upper portion of the bed material storage container are respectively connected. 2. A bed material processing apparatus in a pressurized fluidized bed boiler, characterized in that a line for supplying compressed air is connected upstream of a dust collection hopper inlet side connection portion of a pipeline in a bed material feeding direction. .