JPH06137515A - Pressure fluidized bed boiler - Google Patents

Abstract

PURPOSE:To uniformly cool ash and to simplify a structure of an ash discharging system by providing a fluidized bed type ash cooler for containing ash in collected exhaust gas. CONSTITUTION:Ash in exhaust gas collected by a cyclone 4 and a high temperature dust removing unit is supplied directly to a fluidized bed type two-stage ash cooler 20. The cooler 20 has air chambers 23a, 23b having many nozzles for fluidizing the ash stepwisely in a lower part to receive the ash while fluidizing the ash by the chamber 23a of an inlet side to uniformly disperse to cool it. The ash is further fluidized in the chamber 23b of an outlet side and cooled. Thus, a heat transfer efficiency is improved to uniformly cool the ash, and a structure of the ash discharge system can be simplified.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pressurized fluidized bed boiler applied to thermal power generation and the like.

[0002]

2. Description of the Related Art FIG. 3 is an explanatory diagram of an ash discharging system in a conventional pressurized fluidized bed boiler used for thermal power generation and the like. In the figure, the ash contained in the high-temperature and high-pressure exhaust gas discharged from the pressurized fluidized bed boiler (not shown) is collected by the cyclone 4 and cooled by the water-cooled ash cooler 8 by the screw feeder, and then the ash storage hopper 9 ,
The ash lock hopper system including the decompression hopper 10 and the like sends the ash to a silo. In the figure, reference numeral 6 is a high temperature and high pressure exhaust gas pipe, 14 is a pressure equalizing line,
Reference numeral 15 is an airtight valve, 16 is a rotary valve, and 17 is an injector.

A certain amount of ash collected by the cyclone 4 is sent to an ash storage hopper 9 while being cooled by a water-cooled ash cooler 8. Since the pressure in the ash storage hopper 9 is the same as that of the cyclone 4, it is necessary to reduce the pressure in order to send it to the ash silo in a pressure state of about atmospheric pressure. Therefore, the ash storage hopper 9 and the decompression hopper 1
A state in which a predetermined amount of ash is contained in the decompression hopper 10 by supplying a certain amount of ash to the decompression hopper 10 by the rotary valve 16 while opening the airtight valve 15 located between 0 and 0 to equalize the pressure of both. Then, the rotary valve 16 is closed and the airtight valve 15 is also closed. At this stage, the pressure in the decompression hopper 10 is almost equal to that in the cyclone 4. Therefore, after the pressure in the decompression hopper 10 is reduced to the pressure level on the ash silo side by using the pressure equalizing line 14, the pressure in the lower part of the decompression hopper 10 is reduced. The airtight valve 15 is opened, and a fixed amount of ash is supplied to the injector 17 by the rotary valve 16 and transferred to the ash silo by carrier air.

[0004]

In the conventional pressurized fluidized bed boiler as described above, as the capacity increases, the amount of ash discharged increases, but the ash cooler 8 which has been frequently used conventionally is cooled. Since the ash is cooled through the screw and the casing, its heat transfer efficiency is poor and therefore the structure becomes large. In addition, the ash is not cooled uniformly, and the length of the ash cooler 8 has to be sufficiently long to protect the equipment on the downstream side, particularly the rotary valve 16 and the like. There are problems in terms of cost and reliability.

[0005]

A pressurized fluidized bed boiler according to the present invention is intended to solve the above-mentioned problems. A cooler for exchanging heat with ash through a cooling pipe and a gas are jetted to remove the ash. A fluidized-bed ash cooler having a fluidized air chamber inside and containing the ash in the collected exhaust gas is characterized.

[0006]

That is, in the pressurized fluidized bed boiler according to the present invention, a flow having a cooler for exchanging heat with the ash via a cooling pipe and a wind chamber for jetting gas to fluidize the ash is provided. A fluidized bed ash cooler is provided to contain the ash contained in the exhaust gas collected in the fluidized bed ash cooler. Instead of the conventional ash cooler and ash storage hopper, the fluidized bed ash cooler is used. Since the ash is provided, the heat transfer efficiency is improved, the ash is uniformly cooled, and the structure of the ash discharge system is simplified.

[0007]

1 and 2 are explanatory views of an ash discharging system in a pressurized fluidized bed boiler according to an embodiment of the present invention. In the figure, the pressurized fluidized bed boiler according to the present embodiment is used for thermal power generation, etc., and the ash contained in the high temperature and high pressure exhaust gas discharged from the pressurized fluidized bed boiler 1 is cyclone 4 and high temperature dedusting. It is collected by the device 5, cooled by an ash lock hopper system 7 including a fluidized bed type two-stage ash cooler 20, a fluidized bed type decompression hopper 21 and the like, and is sent to an ash silo. In the figure, reference numeral 2 is a pressure vessel, 3 is a heat transfer pipe, 6 is a high temperature and high pressure exhaust gas pipe, 14 is a pressure equalizing line, 15 is an airtight valve, 16 is a rotary valve, 17 is an injector, 18 is an ash discharge pipe, 2
2 is a foreign matter discharge hopper, 23 is a wind chamber, 24 is a cooler, 25
Is a decompression line.

The ash collected by the cyclone 4 is directly supplied to the fluidized bed type two-stage ash cooler 20. Similarly, the ash collected by the high-temperature dedusting device 5 is also directly supplied to the fluidized bed type two-stage ash cooler 20. In this two-stage ash cooler 20, at least two air chambers 23 equipped with a large number of air nozzles for fluidizing the ash are provided stepwise in the lower part of the inside, and the ash is fluidized by the air chamber 23a on the inlet side. It has both of the effect of receiving it inside while making it uniform and of uniformly dispersing it, and the effect of cooling. Further, a cooler 24 is incorporated above the air chamber 23a in order to increase the effect of cooling the ash. Further, an air chamber 23b is provided on the outlet side and a cooler 24 is provided above the air chamber 23b so that the ash cooled in the inlet air chamber 23a is further fluidized and sufficiently cooled. Further, the fluidized bed type two-stage ash cooler 20 is provided with a decompression line 25 between it and the exhaust gas pipe 6 of high temperature and high pressure so that the ash can be smoothly received inside.

In order to put the ash cooled by the fluidized bed type two-stage ash cooler 20 into the fluidized bed type decompression hopper 21 on the downstream side,
The outlet of the fluidized bed type two-stage ash cooler 20 is equipped with a rotary valve 16 and an airtight valve 15, and the fluidized bed type decompression hopper 2 is provided.
It is connected with 1 entrance. The fluidized bed type decompression hopper 21 has a built-in cooler 24, an air nozzle for fluidization, etc., and decompresses the ash that has been pressurized inside to a normal pressure using a pressure equalizing line 14, an airtight valve 15, etc. While being cooled by the cooler 24, it is caused to flow downward by the action of the air nozzle, is guided to the injector 17 by the ash discharge pipe 18, and is transferred to the ash silo by the carrier air. In addition, the fluidized bed type two-stage ash cooler 2
The cooling effect can be further enhanced by covering the outer circumference of the body portion of No. 0 with a water cooling jacket.

As described above, the present pressurized fluidized bed boiler uses the fluidized bed type two-stage ash cooler 20 for ash storage, which also serves as ash cooling, in place of the conventional ash cooler and ash storage hopper. Cooler 24 instead of the reduced pressure hopper
By using the fluidized bed type decompression hopper 21 with
The structure of the ash processing system is simplified and the reliability is improved at the same time. That is, with the ash completely cooled by the fluidized bed type two-stage ash cooler 20, a downstream fluidized bed type decompression hopper 21 is provided.
Therefore, the rotary valve 16 installed between them is sufficiently protected and reliability is improved. Further, since the ash discharge system has a simple structure, the total installation height can be reduced, the amount of materials such as steel frames is reduced, and the cost is reduced. Further, by using the fluidized bed type two-stage ash cooler 20, a water-cooled ash cooler using a conventional screw feeder is not required, power for auxiliary machinery such as a drive motor is reduced, and ash is fluidized. Are sequentially performed in the inlet side air chamber 23a and the outlet side air chamber 23b,
The amount of air used for fluidization is reduced.

[0011]

EFFECTS OF THE INVENTION The pressurized fluidized bed boiler according to the present invention is constructed as described above, and since the structure of the ash discharging system is simplified, the cost can be reduced and the heat transfer efficiency can be improved. Since it is cooled uniformly and sent from the fluidized bed ash cooler to the downstream decompression hopper, the rotary valve installed between the two is sufficiently protected and reliability is improved.

[Brief description of drawings]

FIG. 1 is a flow diagram of an ash discharge system in a pressurized fluidized bed boiler according to an embodiment of the present invention.

FIG. 2 is a sectional view thereof.

FIG. 3 is a flow diagram of an ash discharge system in a conventional pressurized fluidized bed boiler.

[Explanation of symbols]

 1 Pressurized Fluidized Bed Boiler 2 Pressurized Container 3 Heat Transfer Tube 4 Cyclone 5 High Temperature Dust Removal Device 6 High Temperature and High Pressure Exhaust Gas Pipe 7 Ash Lock Hopper System 14 Pressure Equalizing Line 15 Airtight Valve 16 Rotary Valve 17 Injector 18 Ash Discharge Pipe 20 Fluid Bed Type two-stage ash cooler 21 fluidized bed type decompression hopper 22 foreign matter discharge hopper 23 wind chamber 24 cooler 25 decompression line

Claims (1)

[Claims] 1. A flow for containing ash in the collected exhaust gas having a cooler for exchanging heat with ash through a cooling pipe and a wind chamber for jetting gas to fluidize the ash. A pressurized fluidized bed boiler equipped with a floor ash cooler.