JPH10169912A - Bed ash extracting device of pressurized fluidized boiler - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the weight and the construction cost of a pressure vessel by lowering the height of steel frames which supports the pressure vessel and recycle a bed ash by charging the bed ash into a bed material storage vessel from a lock hopper again, wherein a part of the bed ash which is produced as a result of combustion in a body of a fluidized bed boiler is introduced to the lock hopper which is disposed above the pressure vessel without making use of gravity and it is no more necessary to dispose the lock hopper below the pressure vessel. SOLUTION: A lock hopper 30 is disposed outside of and above a pressure vessel 1. The lock hopper 30 is connected with an ash feed pipe 11 of an ash extracting hopper 10 of a fluidized bed boiler body 2 by means of an extracting pipe 39. A closure valve 40 for reducing an inner pressure is mounted on the lock hopper 30. The lock hopper 30 is also connected with a bed material storage vessel 24 which is disposed in the pressure vessel 1 by means of a charging pipe 41.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a bed ash extraction device for a pressurized fluidized-bed boiler.

[0002]

2. Description of the Related Art An example of a pressurized fluidized-bed boiler will be described with reference to FIG.
Is provided with a fluidized-bed boiler main body 2, and a plurality of diffuser tubes 3 are disposed in a lower portion of the fluidized-bed boiler main body 2. The diffuser tubes 3 are pressurized in the pressure vessel 1. The air 4 is taken into a wind box 37 from an intake pipe 36 provided with an ash cooler 19 described later on the way, and is blown upward.

A fuel supply pipe 5 for supplying a fuel such as coal slurry is disposed above the air diffuser 3.
A bed material 7 mixed with a desulfurizing material such as limestone and coal ash for forming the fluidized bed 6 is supplied from a bed material storage container 24, and supplied from the compressor 8 into the pressure container 1. The pressurized air 4 is supplied from the intake pipe 36 to the diffuser pipe 3 via the wind box 37 and is jetted upward to form a fluidized bed 6, and the fuel supplied from the fuel supply pipe 5 is supplied to the fluidized bed 6. The water is heated by the heat transfer tube 9 disposed in the formation part of the fluidized bed 6 to generate steam by being stirred and efficiently burned.

[0004] The bed height of the fluidized bed 6 is controlled according to a boiler load command. When the bed height of the fluidized bed 6 is increased with an increase in load, a bed material storage container is required. L-shaped bed material injection pipe 25 connected to the bottom of
By supplying the pressurized air 4 in the pressure vessel 1 by adjusting the opening of the injection valve 26, the bed material storage vessel 2
When the bed material 7 in the bed 4 is injected into the fluidized-bed boiler main body 2 through the bed material injection pipe 25, and when the bed height of the fluidized bed 6 is lowered with a decrease in load, the bed material storage container 2
The bed material 7 in the fluidized-bed boiler main body 2 is reduced by reducing the internal pressure of the bed 4 by adjusting the opening degree of the extraction valve 27, so that the bed-material extracting pipe 2 protruding from the side of the fluidized-bed boiler main body 2.
8 to a bed material storage container 24.

If the bed material 7 in the fluidized-bed boiler body 2 increases due to ash or the like generated by combustion and the bed height of the fluidized bed 6 increases with respect to the current load, the ash and bed Part of the material 7 (hereinafter referred to as bed ash) falls as a total surplus from the space between the air diffusers 3 to the ash hopper 10 provided on the lower side, and the lower ash slasher From the outlet pipe 11 via the ash transfer nozzle 29, the lock hopper 3
After being extracted to zero, the rotary valve 31 cuts out a required amount into a discharge line 32, and is introduced into the bed material silo 33 from the discharge line 32 by suction by the operation of the blower 23. The bed ash stored in the silo 33 is appropriately cut out from the rotary valve 34 and carried out by a truck 35 or the like.

In the upper part of the fluidized bed boiler main body 2, a plurality (for example, six) of cyclones 14 through which a high-temperature and high-pressure exhaust gas 12 after heating water in the heat transfer tube 9 is guided through a branch duct 13. The ash in the exhaust gas 12 is disposed to separate the ash from the exhaust gas 12, and the exhaust gas 12 from which the ash has been separated by the cyclone 14 is sent to a gas turbine 16 provided outside the pressure vessel 1 via an exhaust gas pipe 15. The gas turbine 16 is supplied to drive the gas turbine 16. The gas turbine 16 drives the above-described compressor 8 and also drives the gas turbine generator 17 with excess power.

The separated ash 1 separated by the cyclone 14
8 is the ash cooler 19 from the intake pipe 36 to the wind box 3
After being cooled by the pressurized air 4 supplied to the diffuser 3 via 7, the ash is transported to an ash treatment device (not shown) outside the pressure vessel 1 by an ash transport pipe 20. The pressurized air 4 supplied from the intake pipe 36 to the air diffuser 3 via the wind box 37 is supplied to the
Is heated by depriving the fluid of the fluidized bed 6
Is formed.

Incidentally, the bed material storage container 24 is usually
Plural pieces are provided, and the total capacity is set to a capacity enough to store the bed material 7 required when the operation is performed with a load of 100% in the fluidized-bed boiler main body 2. In the drawing, reference numeral 38 denotes a start-up burner for heating the pressurized air 4 supplied from the intake pipe 36 to the air diffuser 3 via the wind box 37 at the time of start-up.

[0009]

However, in the conventional pressurized fluidized-bed boiler as described above, part of the bed ash generated by combustion in the fluidized-bed boiler body 2 is transferred to the lock hopper 30 by utilizing gravity. It is supposed to drop,
Since the lock hopper 30 needs to be installed below the pressure vessel 1, the pressure vessel 1 must be installed at a high position or the ground below the pressure vessel 1 must be dug. There is a disadvantage that the height of the supporting steel frame is increased, leading to an increase in the weight of the supporting steel frame and an increase in cost.

Further, in the case of the conventional pressurized fluidized bed boiler, it is impossible to directly re-use the bed ash dropped into the lock hopper 30 during operation by re-introducing the bed ash into the bed material storage container 24. When the bed ash is to be re-introduced into the bed material storage container 24, a dedicated lock hopper needs to be installed above the pressure vessel 1 separately from the lock hopper 30 installed below the pressure vessel 1. was there.

In view of such circumstances, the present invention introduces a part of bed ash generated by combustion in a fluidized-bed boiler main body without using gravity into a lock hopper installed above a pressure vessel. It is possible to eliminate the need for installing a lock hopper below the pressure vessel, reduce the height of the steel frame supporting the pressure vessel, reduce the weight and reduce the cost, and operate the bed during operation. An object of the present invention is to provide a bed ash extraction device for a pressurized fluidized-bed boiler in which ash can be re-input from a lock hopper into a bed material storage container and reused.

[0012]

SUMMARY OF THE INVENTION According to the present invention, a lock hopper is provided outside and above a pressure vessel, and the ash is removed from an ash removal hopper of a fluidized bed boiler body provided in the lock hopper and the pressure vessel. The pipes are connected by an extraction pipe, a lock hopper is provided with an on-off valve for reducing the internal pressure, and the lock hopper is connected to a bed material storage container disposed in the pressure vessel by a charging pipe. The present invention relates to a bed ash extraction device for a pressurized fluidized bed boiler.

[0013] In the bed ash extracting device of the pressurized fluidized bed boiler, pressurized air in a pressure vessel or compressed air by a compressor is supplied to an extraction pipe as transfer air when the bed ash is extracted to the lock hopper. Can be connected.

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

If the amount of bed material in the fluidized bed boiler body increases due to ash or the like generated by combustion and the bed height of the fluidized bed rises with respect to the current load, the internal pressure reducing on-off valve is opened and locked. When the internal pressure of the hopper is reduced, the bed ash is transferred from the ash extraction pipe of the ash extraction hopper of the fluidized bed boiler to the lock hopper through the extraction pipe due to the pressure difference, and the bed ash extracted by the lock hopper is removed. Part of the bed material is re-input to the bed material storage container via the input pipe as needed, and is reused.

In the above-mentioned bed ash extracting device for a pressurized fluidized bed boiler, pressurized air in a pressure vessel or compressed air by a compressor is supplied to an extraction pipe as transfer air when extracting bed ash to a lock hopper. When the supply pipe is connected, pressurized air in the pressure vessel is supplied to the extraction pipe from the pipe as transfer air when the bed ash is extracted to the lock hopper, or compressed by a compressor as transfer air. When air is supplied from the pipe to the extraction pipe, the transport ratio of bed ash (the ratio of solid bed ash to air as the transport medium) can be adjusted appropriately, and the extraction of the bed ash to the lock hopper is more stable. Will be done.

Further, when the pressurized air remaining in the pressure vessel is used for transferring bed ash to the lock hopper when the gas turbine driven by the pressurized fluidized bed boiler trips,
Immediately after the trip of the gas turbine, the bed ash is rapidly transferred from the fluidized-bed boiler main body to the bed material storage container in the pressure vessel, and it becomes possible to prepare for restart, which is also effective for shortening the restart time. .

[0018]

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

FIG. 1 is an example of an embodiment of the present invention. In the figure, the portions denoted by the same reference numerals as those in FIG. 2 represent the same components, and the basic configuration is the same as that of the conventional device shown in FIG. This is the same as that of the first embodiment, except that a lock hopper 30 is disposed outside and above the pressure vessel 1 as shown in FIG. Ash extraction pipe 11 of ash extraction hopper 10 of fluidized bed boiler body 2
Are connected by an extraction pipe 39, and an open / close valve 40 for reducing the internal pressure is provided in the lock hopper 30, and the lock hopper 30
And the bed material storage container 24 disposed in the pressure container 1 is connected by a charging pipe 41.

In the illustrated example, an ash transfer nozzle 29 connected to the ash extraction pipe 11 is provided at the upstream end of the extraction pipe 39, and the ash transfer nozzle 29 is provided with a lock hopper 3
A pipe 44 for supplying the pressurized air 4 in the pressure vessel 1 or the compressed air 43 by the compressor 42 as a transfer air when the bed ash is extracted to 0 is connected, and the bed ash is extracted to the lock hopper 30. When the pressurized air 4 in the pressure vessel 1 is supplied to the extraction pipe 39 through the ash transfer nozzle 29 as the transfer air at the time of discharge, the pressurized air valve 45 is used.
Is opened, the compressed air valve 46 is closed, and the transfer air valve 4 is closed.
7, the compressed air 43 from the compressor 42 is supplied to the extraction pipe 39 through the ash transfer nozzle 29 as the transfer air when the bed ash is extracted to the lock hopper 30. The valve 45 is closed, the compressed air valve 46 is opened to drive the compressor 42, and the transfer air valve 47 is opened.

An orifice 48 and a bag filter 49 are provided downstream of the internal pressure reducing on-off valve 40 provided in the lock hopper 30. When the internal pressure of the lock hopper 30 is reduced, The air containing the dust discharged from the filter 30 is discharged to the atmosphere after the dust is removed by the bag filter 49. Note that the lock hopper 30 is provided without the bag filter 49.
It is needless to say that the air containing dust discharged from the apparatus may be introduced into a flue or ash treatment device (not shown).

Further, a required amount of bed ash may be added to the bed material storage container 24 as needed in the middle of the input pipe 41 connecting the lock hopper 30 and the bed material storage container 24 disposed in the pressure vessel 1. Rotary valve 3 for cutting into
1 'is provided, and a part of the bed ash extracted into the lock hopper 30 is cut into a discharge line 32 by a required amount by a rotary valve 31 as necessary, as in the conventional case, and The suction by the operation is introduced from the discharge line 32 to the bed material silo 33.

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

When the bed material 7 in the fluidized-bed boiler body 2 increases due to ash or the like generated by combustion and the bed height of the fluidized bed 6 rises with respect to the current load, the internal pressure reducing on-off valve 40 To reduce the internal pressure of the lock hopper 30, open the pressurized air valve 45, close the compressed air valve 46, and open the transfer air valve 47 to apply pressure in the pressure vessel 1 as transfer air. The compressed air 4 is supplied from the pipe 44 to the extraction pipe 39 via the ash transfer nozzle 29, or the compressed air valve 45 is closed and the compressed air valve 46 is opened to drive the compressor 42 and transfer the compressed air. The air in the pressure vessel 1 is opened as the transfer air by opening the air valve 47 for transfer.
When the pressurized compressed air 43 is supplied from the pipe 44 to the extraction pipe 39 via the ash transfer nozzle 29, bed ash is discharged from the ash extraction pipe 11 of the ash extraction hopper 10 of the fluidized-bed boiler body 2 to the extraction pipe 39. It is transferred to the lock hopper 30 through.

A part of the bed ash extracted into the lock hopper 30 is re-charged into the bed material storage container 24 via the charging pipe 41 by driving the rotary valve 31 'as needed, and is reused. On the other hand, a part of the bed ash extracted into the lock hopper 30 is cut out into a discharge line 32 by a required amount by driving a rotary valve 31 as necessary, as in the conventional case, and is sucked by the operation of the blower 23. Thereby, it is introduced into the bed material silo 33 from the discharge line 32.

The transfer ratio of the bed ash (the ratio between the solid bed ash and the air as the transfer medium) can be appropriately adjusted by adjusting the transfer air amount by adjusting the opening of the transfer air valve 47. Thus, the extraction of the bed ash into the lock hopper 30 is further stabilized. Further, by using the pressurized air 4 in the pressure vessel 1, the size of the compressor 42 can be reduced, and the motive power of auxiliary equipment can be reduced.

Further, when the gas turbine 16 trips, the pressurized air 4 remaining in the pressure vessel 1 is removed by the lock hopper 3.
When the bed ash is used to transfer the bed ash to the bed material storage container 24 in the pressure vessel 1 immediately after the trip of the gas turbine 16, the bed ash is quickly transferred from the inside of the fluidized bed boiler main body 2 to restart. It is possible to prepare for this, and it is also effective for shortening the restart time.

In this way, a part of the bed ash generated by the combustion in the fluidized bed boiler body 2 can be introduced into the lock hopper 30 installed above the pressure vessel 1 without using gravity, and A lock hopper 30 is provided below the container 1.
Can be eliminated, the height of the steel frame supporting the pressure vessel 1 can be reduced to reduce the weight and cost, and the bed ash can be removed during operation by the lock hopper 3.
From 0 to the bed material storage container 24 for re-use,
Further, when the gas turbine 16 driven by the pressurized fluidized bed boiler is tripped, the pressurized air 4 remaining in the pressure vessel 1 is used for transferring the bed ash to the lock hopper 30, so that the gas turbine 16 Immediately after the trip, the bed ash is rapidly discharged from the fluidized-bed boiler body 2 into the pressure vessel 1.
It can be transferred to the bed material storage container 24 inside and prepared for restart, and the restart time can be shortened.

The bed ash extraction device of the pressurized fluidized-bed boiler of the present invention is not limited to the above-described example, but may be variously modified without departing from the gist of the present invention. Of course.

[0030]

As described above, according to the bed ash extracting device of the pressurized fluidized-bed boiler of the present invention, the lock hopper installed above the pressure vessel is burned in the fluidized-bed boiler main body. Part of the generated bed ash can be introduced without using gravity, which eliminates the need to install a lock hopper below the pressure vessel, and reduces the height of the steel frame supporting the pressure vessel to reduce weight. Bed ash can be reused by re-injecting bed ash from the lock hopper into the bed material storage vessel during operation, and further, tripping of the gas turbine driven by the pressurized fluidized bed boiler. At times, the pressurized air remaining in the pressure vessel is used to transfer the bed ash to the lock hopper, so that the bed ash is rapidly absorbed from inside the fluidized bed boiler immediately after the gas turbine trip. It can be transported to the timber reservoir,
An excellent effect that the restart time can be shortened can be obtained.

[Brief description of the drawings]

FIG. 1 is an overall schematic configuration diagram of an example of an embodiment of the present invention.

FIG. 2 is an overall schematic configuration diagram of a conventional example.

[Explanation of symbols]

 Reference Signs List 1 pressure vessel 2 fluidized bed boiler main body 4 pressurized air 10 ash extraction hopper 11 ash extraction pipe 24 bed material storage vessel 30 lock hopper 39 extraction pipe 40 internal pressure reducing open / close valve 41 input pipe 42 compressor 43 compressed air 44 pipe

Claims (2)

[Claims] 1. A lock hopper is disposed outside and above a pressure vessel, and the lock hopper is connected to an ash extraction pipe of an ash extraction hopper of a fluidized bed boiler main body disposed in the pressure vessel by an extraction pipe. And a lock hopper is provided with an on-off valve for reducing the internal pressure, and the lock hopper and a bed material storage container disposed in the pressure container are connected by an input pipe. Output device. 2. The pump according to claim 1, wherein a pipe for supplying pressurized air in a pressure vessel or compressed air by a compressor as a transfer air when the bed ash is extracted to the lock hopper is connected to the extraction pipe. Bed ash extraction device for pressure fluidized bed boiler.