JPH08219412A - Discharging device for cyclone ash in pressurized fluidized bed combustion plant - Google Patents

Abstract

PURPOSE: To prevent clogging due to ash in a pipeline or an instrument by a method wherein ash discharging pipes are led out of a pressure vessel individually from a multitude of internal cyclones and are piped independently to a reducer while ash is injected out of independent orifices, mounted in the reducer respectively. CONSTITUTION: Respective ash discharging pipes 4 for internal cyclones 3 are extended independently out of a pressure vessel 1 respectively and are connected to a multitude of respective orifices 11 arranged in a reducer 7. These plurality of orifices 11 are provided by a number corresponding to the number of a multitude of internal cyclones 3 and are arranged on the opposing wall surfaces of the reducer 7 so as to be arrayed in series opposingly to each other. When clogging is caused in the ash discharging pipe 4, a force to release the clogging is increased suddenly.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a cyclone ash discharge device in a pressurized fluidized bed combustion plant.

[0002]

2. Description of the Related Art Conventionally, a pressurized fluidized bed combustion plant of this type is equipped with a fluidized bed boiler 2 and a plurality of internal cyclones 3 in a pressure vessel 1 as shown in FIG. To burn coal and the like, and to introduce combustion gas containing the combustion ash (hereinafter, simply referred to as ash) into the internal cyclone 3 to collect the ash and guide the exhaust gas to a gas turbine (not shown) or the like. It is configured.

The ash collected by the internal cyclone 3 is
A part of the exhaust gas is collected from the ash discharge pipe 4 to the collecting pipe 5, collected into one to three cyclone ash discharge lines 6 (one in FIG. 1), and carried out of the pressure vessel 1. . The collecting pipe 5 may be installed outside the pressure vessel 1. An ash cooler (not shown) is provided between the ash discharge pipe 4 and the collecting pipe 5 as needed.

The ash carried out to the outside of the pressure vessel 1 by the cyclone ash discharge line 6 is jetted from an orifice 8 provided at the inlet of the decompressor 7 to reduce the pressure to near atmospheric pressure, and then the external cyclone. It is collected by the ash hopper 10 of 9.

[0005]

However, the above-mentioned conventional cyclone ash discharging mechanism, as shown in FIG. 5, is one to several of the many ash discharging pipes 4 between the internal cyclone 3 and the collecting pipe 5. When the blockage M caused by ash is generated in the ash discharge pipe 4 of the book, or when the blockage M starts to occur, the gas flowing from the other normally flowing ash discharge pipe 4 into the collecting pipe 5 is indicated by an arrow Y. Then, the backflow is performed from the downstream side of the closed portion M of the discharge pipe 4 in which the above-mentioned blockage has occurred. As a result, the pressure difference for releasing this blockage is not the initial pressure difference P0-P3 (where P0 is the pressure at the outlet of the internal cyclone 3 and P3 is the pressure at the inlet of the orifice 8 of the decompressor 7). The pressure difference is P1-P2 (where P1 is the pressure in the ash discharge pipe 4 and P2 is the pressure in the collecting pipe 5) which is smaller than this.

The pressure P at each part of the plant is
Since there is a relationship of P0>P1>P2>P3> P4 (where P4 is the pressure inside the decompressor 7), the pressure difference P1
-P2 is much smaller than the pressure difference P0-P3, and as a result, the force for releasing the blockage is drastically reduced.

The present invention has been made in order to solve the above-mentioned conventional problems, and an object thereof is to remove ash in an internal cyclone from the pressure vessel to the outside by using ash in piping or equipment. An object of the present invention is to provide a cyclone ash discharging device in a pressurized fluidized bed combustion plant that can reliably and stably prevent the occurrence of blockage.

[0008]

In order to solve the above problems, a cyclone ash discharging device in a pressurized fluidized bed combustion plant of the present invention comprises a fluidized bed boiler and a large number of internal cyclones in a pressure vessel. Then, the combustion gas from the fluidized bed boiler is introduced into a cyclone to collect the ash in the combustion gas, and the collected ash is carried out of the pressure vessel through a decompressor via an external cyclone. In a device for collecting ash, individually pull out the ash discharge pipes from the above-mentioned many internal cyclones to the outside of the pressure vessel, and pipe them individually to the above decompressor,
It is characterized in that it is configured so as to eject from each single orifice provided in the decompressor. In addition, the bypass pipe is branched from the ash discharge pipe, and the bypass pipe is equipped with a shutoff valve and an auxiliary orifice so that the bypass pipe is guided to the decompressor. The plurality of orifices are arranged in series on one wall surface of the pressure reducer, and the plurality of orifices are also arranged in series on the opposite wall surface of the pressure reducer so as to face the plurality of orifices.

[0009]

An embodiment of the present invention will be described below with reference to the drawings. In FIG. 1, the pressure vessel 1, the fluidized bed boiler 2, the internal cyclone 3, the ash discharge pipe 4, the decompressor 7, the external cyclone 9 and the ash hopper 10 are the same as those of the conventional apparatus shown in FIG. The description is omitted.

In FIG. 1, each ash discharge pipe 4 of the internal cyclone 3 is independently extended to the outside of the pressure vessel 1,
Each of the orifices 11 is provided in the decompressor 7 in large numbers.
It is connected to the. These plural orifices 11 are
The orifices 11 are arranged in a number corresponding to the number of the above-mentioned internal cyclones 3, and the orifices 11 are arranged facing each other on the opposite wall surfaces of the decompressor 7, and the orifices 11 on each side are arranged in series. There is.

Therefore, during normal operation, there is a pressure difference between P1 and P3, but when blockage occurs in the ash discharge pipe 4, the pressure difference before and after the block portion N becomes P1 and P4, and the blockage occurs. The force to release is sharply increased.

FIG. 2 shows another embodiment. A bypass pipe 12 is branched from each of the ash discharge pipes 4 and connected to an auxiliary orifice 13, and a cutoff valve 14 is provided in the bypass pipe 12.

Therefore, by providing the bypass pipe 12, the gas flow rate in the ash discharge pipe 4 can be greatly increased, and as a result, the blockage can be easily removed. The gas flow rate and flow velocity in the ash discharge pipe 4 cannot be controlled because they are determined by the diameter of the orifice 11 provided at the inlet of the decompressor 7. Therefore, by providing the bypass pipe 12 and equipping it with the auxiliary orifice 13 and the shutoff valve 14, it becomes possible to remove the blockage by temporarily flowing a large amount of gas.

FIG. 3 shows still another embodiment.
Several bypass pipes 12 are combined into a collecting pipe 15 and connected to an auxiliary orifice 16 arranged at the top of the decompressor 7.

The system of the present invention, when the pressure in the pressure vessel 1 is low at the time of starting and stopping the plant,
Since the gas flow rate in the ash discharge pipe 4 is drastically reduced, clogging is particularly likely to occur. In this case, it is possible to prevent the blockage by opening the shutoff valve 14 in advance.

The structure of the decompressor 7 is as follows in the conventional system.
The number of orifices 8 is the same as the cyclone ash discharge line 1
Since the number of nozzles is about three or three, the jet flow direction can be set to the longitudinal direction (axial direction) of the decompressor 7, but when a large number of orifices 11 are provided as in the present invention, decompression is performed. Since the tank of the container 7 becomes huge and the orifices 11 are arranged radially, it is virtually impossible to install a large number of orifices (several dozens in many cases).

Therefore, as shown in FIG. 1 or 3, the decompressor 7 is regularly arranged in the longitudinal direction of the tank, and is similarly arranged on the opposite side so that the pair of orifices 11, 11 face each other. Attach to. Therefore, the jet flows from the left and right orifices 11 interfere with each other, and the impact force of ash and gas is attenuated, and as a result, the wear in the tank of the decompressor 7 can be reduced. Further, by efficiently arranging the orifices 11 in series, the decompressor 7 can be designed compactly.

[0018]

【The invention's effect】

1) Since the ash discharge pipes are individually led out of the pressure vessel from a large number of internal cyclones and are individually connected to the decompressor, and the individual orifices provided in the decompressor are used for injection, the internal cyclone When the ash is carried out of the pressure vessel to the outside, it is possible to reliably and stably prevent the occurrence of clogging due to the ash in the pipe or the equipment. 2) Since the bypass pipe is branched from the ash discharge pipe, and the bypass pipe is equipped with a shutoff valve and an auxiliary orifice to guide the decompressor, it is possible to prevent clogging in advance. 3) Since a plurality of orifices are arranged in series on one wall surface of the pressure reducer, and a plurality of orifices are also arranged in series on the opposite wall surface of the pressure reducer so as to face the plurality of orifices, It became possible to design the decompressor compactly

[Brief description of drawings]

FIG. 1 is an explanatory view showing an embodiment of a cyclone ash discharging device of the present invention.

FIG. 2 is an explanatory diagram showing another embodiment of the present invention.

FIG. 3 is an explanatory view showing still another embodiment of the present invention.

FIG. 4 is an explanatory view showing a pressurized fluidized bed combustion plant and a conventional cyclone ash discharging device.

FIG. 5 is an explanatory diagram of blockage of an ash discharge pipe.

[Explanation of symbols]

 1 pressure vessel 2 fluidized bed boiler 3 internal cyclone 4 ash discharge pipe 5 collecting pipe 6 cyclone ash discharge line 7 decompressor 8 orifice 9 external cyclone 10 ash hopper 11 orifice 12 bypass pipe 13 auxiliary orifice 14 shutoff valve 15 collecting pipe 16 auxiliary orifice M Blocked part N Blocked part Y Arrow

Claims (3)

[Claims] 1. A pressure vessel equipped with a fluidized-bed boiler and a number of internal cyclones, and the combustion gas from the fluidized-bed boiler is introduced into the cyclone to collect the ash in the combustion gas and to collect the dust. In a device that carries out the ash discharged to the outside of the pressure vessel and collects the ash from the decompressor through an external cyclone, individually removes the ash discharge pipes from the multiple internal cyclones to the outside of the pressure vessel. Piping up to the above pressure reducer,
A cyclone ash discharging device in a pressurized fluidized bed combustion plant, characterized in that each of the depressurizers is configured to inject from a single orifice. 2. The bypass pipe is branched from the ash discharge pipe, and the bypass pipe is equipped with a shutoff valve and an auxiliary orifice so as to guide the bypass pipe to the decompressor. Cyclone ash discharge device in a fluidized bed combustion plant. 3. The plurality of orifices are arranged in series on one wall surface of the pressure reducer, and the plurality of orifices are also arranged in series on the opposite wall surface of the pressure reducer so as to face the plurality of orifices. The cyclone ash discharging device in the pressurized fluidized bed combustion plant according to claim 1 or 2.