JP2000088236A - Method and system for supplying fuel slurry and fuel slurry purging method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a duct from being choked with slurry in the vicinity of forward end of a slurry ejection nozzle by opening a delivery purge valve, a piping purge valve and a fuel shut off valve sequentially and then closing the fuel shut off valve and the piping purge valve before a wetting valve and a drain valve are opened. SOLUTION: Purge air is supplied by opening a delivery purge valve 12b and fuel slurry sealed in an upstream slurry supply section 3a is pushed out to a slurry circulation passage 4. A piping purge valve 14b is then opened and fuel slurry in a middle stream slurry supply section 3b is pressurized by process air. Subsequently, a fuel shut off valve is opened and fuel slurry remaining in the middle stream slurry supply section 3b is pressure fed at a breath into a furnace by process air. Thereafter, the fuel shut off valve 6 is closed followed by closing of a high pressure purge main valve 18b and the piping purge valve 14b. Finally, a wetting valve 8b and a drain valve 9b are opened and the duct at the middle stream slurry supply section 3b is filled with water.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel slurry supply apparatus for supplying a fuel slurry to a pressurized fluidized bed boiler, a purge method thereof, and a fuel slurry supply method.

[0002]

2. Description of the Related Art In recent years, a pressurized fluidized bed boiler capable of burning fuel with high combustion efficiency, desulfurization in a furnace, and downsizing of the boiler has been researched and developed.

FIG. 8 is a configuration diagram showing an example of a pressurized fluidized bed boiler. In FIG. 8, reference numeral 30 denotes a furnace of a pressurized fluidized-bed boiler, 31 denotes a dust collecting device for collecting waste gas generated in the furnace 30, and 32 denotes a furnace surrounding the furnace 30 and the dust collecting device 31 and being pressurized. A pressure vessel for holding; 33, a dust remover for removing dust from the waste gas passing through the dust collector 31; 34, a dust remover 3;
A gas turbine driven by waste gas passing through 3,
4 b is a compressor disposed coaxially with the gas turbine 34. The air pressurized by the compressor 34b is sent from the floor of the furnace 30 into the furnace 30 as flowing air. Reference numeral 35 denotes a heat exchanger disposed in the furnace 30, and reference numeral 36 denotes a steam turbine driven by steam from the heat exchanger 35. Water is supplied from the outside to the heat exchanger 35, and the water is vaporized by the heat of the furnace 30 in the heat exchanger 35,
The steam is sent to the steam turbine 36. 1 is a slurry tank for storing fuel slurry, 3 is a slurry supply path for supplying fuel slurry from the slurry tank 1 to the furnace 30, and 7 is a slurry supply path 3.
It is a slurry pump arranged in.

In such a pressurized fluidized-bed boiler, the fuel is a slurry-like (for example, coal-water slurry (CWM)) which is a slurry obtained by mixing pulverized coal (which may include limestone) with water. Is supplied to the furnace 30 as a fuel slurry. Fuel slurries have the property that water and solid particles are easily separated and are muddy, so they have strong tackiness and easily adhere to pipes. Therefore, the furnace 30
At the start of the operation, the fuel slurry is filled in the pipeline of the slurry supply path 3 or when the operation of the furnace 30 is stopped, the slurry supply path 3
However, there is a problem that the fuel slurry remains in the pipeline and is dried and fixed in the pipeline of the slurry supply passage 3 to block the pipeline.

As a fuel slurry purging method for a pressurized fluidized-bed boiler which solves the above-mentioned problems, Japanese Patent Laid-Open Publication No. Hei.
No. 8 (hereinafter referred to as “A”) discloses a “fuel purging method for a pressurized fluidized-bed boiler”.

FIG. 9 is a block diagram showing an example of a fuel slurry supply device for carrying out the fuel slurry purging method disclosed in Japanese Patent Application Laid-Open Publication No. Hei. In FIG. 9, 1 is a slurry tank for storing a fuel slurry, and 2 is a furnace 30 of a pressurized fluidized-bed boiler in which a fuel slurry is fed from a tapered tip portion 2b.
A tubular air jet nozzle 2a is provided concentrically in the pipeline of the slurry jet nozzle 2 and is provided with a dispersing air pipe 2c having a tip opening near the tip 2b of the slurry jet nozzle 2. Dispersed air pipe insertion sections 3a, 3b, 3c into which the dispersed air pipes 2a are inserted into the slurry injection nozzle 2 are upstream, middle, and downstream parts of the slurry supply path 3, respectively. A slurry supply path and a downstream slurry supply path. The fuel slurry stored in the slurry tank 1 is supplied to the upstream slurry supply passage 3a and the middle slurry supply passage 3
b, The slurry is supplied to the slurry injection nozzle 2 through the downstream slurry supply path 3c and is injected into the furnace 30. Reference numeral 4 denotes a slurry circulation path having one end communicating with a connecting portion between the upstream slurry supply path 3a and the middle flow slurry supply path 3b and the other end communicating with the upper part of the slurry tank 1. Reference numeral 5 denotes an upstream slurry supply path 3a and the middle flow part. A discharge three-way valve 6 provided at a connection between the slurry supply path 3b and the slurry circulation path 4; a fuel cutoff valve 6 provided at a connection between the middle flow slurry supply path 3b and the downstream slurry supply path 3c; 2
1 is a pressure gauge that detects a pressure difference between a downstream end of the middle slurry supply passage 3b and an upstream end of the downstream slurry supply passage 3c.
Reference numeral 7 denotes a slurry pump provided in the upstream slurry supply passage 3a. The discharge three-way valve 5 switches the upstream part slurry supply path 3a to the middle part slurry supply path 3b or the slurry circulation path 4. The slurry pump 7 pumps the fuel slurry from the upstream to the downstream of the upstream slurry supply passage 3a. 8 is a water supply channel communicating with the vicinity of the downstream end of the middle part slurry supply channel 3b;
Reference numeral 8b denotes a water wetting valve provided in the water supply passage 8, reference numeral 9 denotes a drainage passage communicating with the vicinity of the upstream end of the slurry supply passage 3b in the middle part and the upper part of the slurry tank 1, and reference numeral 9b denotes a drainage passage. Drain valve. Reference numeral 10 denotes an upstream purge air supply path for supplying purge air, 11 denotes a circulation purge air supply path communicating with the vicinity of the junction of the slurry circulation path 4 with the discharge three-way valve 5 and the upstream purge air supply path 10, and 11b denotes a circulation purge air supply path. A circulation purge valve 11 is disposed at a discharge purge air supply passage 12 communicating with the upstream purge air supply passage 10 and the vicinity of the discharge port of the slurry pump 7 in the upstream slurry supply passage 3a.
2b is a discharge purge valve provided in the discharge purge air supply path 12. 13 is a process air supply path for supplying process air, 13b is a fuel dispersed air source valve disposed in the process air supply path 13, and 14 is near the upstream end of the process air supply path 13 and the middle part slurry supply path 3b. Is a pipe purge valve disposed near a junction with the middle slurry supply path 3b, and 15 is a process air supply path.
And a downstream purge air supply passage 15b communicating with the downstream slurry supply passage 3c near the upstream end of the downstream slurry supply passage 3c, and a backflow prevention purge disposed near the junction of the downstream purge air supply passage 15 with the downstream slurry supply passage 3c. A valve, 16 is a fuel dispersing air supply path communicating with the process air supply path 13 and the dispersing air pipe 2a, 16b is a fuel dispersing air regulating valve, which is a flow regulating valve disposed in the fuel dispersing air supply path 16, and 16d is a fuel dispersing air regulating valve. A flow meter 17 is disposed downstream of the fuel-dispersed air control valve 16b of the fuel-dispersed air supply passage 16, and a flow meter 17 is disposed downstream of the fuel-dispersed air supply passage 16d of the fuel-dispersed air supply passage 16 and the process air supply passage 1.
A nozzle purge air supply passage 17 b communicating with the nozzle purge air supply passage 3 is a nozzle purge valve provided in the nozzle purge air supply passage 17. Reference numeral 18 denotes a high-pressure purge air supply path for supplying high-pressure purge air, 18b denotes a high-pressure purge source valve provided in the high-pressure air supply path 18, and 18 'denotes an upstream side of the high-pressure purge source valve 18b of the high-pressure air supply path 18 and circulation purge air supply. A circulating high-pressure purge air supply path communicating with the upstream end of the passage 11, and a middle flow section 19 communicating with the upstream end of the pipe purge valve 14 b of the middle flow purge air supply path 14 and the downstream end of the high-pressure air supply path 18. The high-pressure purge air supply path 20 is a nozzle high-pressure purge air supply path that communicates with the nozzle purge air supply path 17 on the upstream side of the nozzle purge valve 17 b and the downstream end of the high-pressure air supply path 18.

In the fuel slurry supply apparatus having the above-described structure, a conventional fuel slurry purging method disclosed in Japanese Patent Application Laid-Open Publication No. H06-27205 will be described below. FIG. 10 is a flowchart showing a conventional fuel slurry purging method when the operation of the pressurized fluidized-bed boiler is stopped, FIG. 11 is a flowchart showing a shut-off purge step, and FIG. 12 is a flowchart showing a fuel nozzle purging step. During the steady operation of the furnace 30, the discharge three-way valve 5 is connected to the middle part slurry supply passage 3 b, the fuel cutoff valve 6 is opened, the fuel slurry is pressure-fed by the slurry pump 7, and the slurry supply passage from the slurry tank 1. The fuel is supplied to the furnace 30 through the slurry injection nozzle 3 and the slurry injection nozzle 2. At this time, the fuel-dispersed air control valve 16b and the fuel-dispersed air main valve 13b are also opened, and process air is supplied from the dispersed air pipe 2a to the tip 2b of the slurry injection nozzle 2, and the furnace 30 and the fuel slurry are fed together. Has been injected into. Other valves are closed. When the operation of the furnace 30 is stopped, first, as shown in FIG.
1) Subsequently, a fuel nozzle purging step is performed (S2), a bed height lowering operation (S3) is performed until the bed height of the fluidized bed of the furnace 30 becomes 0.2 m, and a fuel nozzle purging step is performed again (S4). Then, the gas turbine 34 is stopped (S5). Here, in the shutoff purge master step (S1), FIG.
As shown in FIG. 1, first, the slurry pump 7 is stopped (S
10), the fuel cutoff valve 6 is closed, and the discharge three-way valve 5 is switched to the slurry circulation path 4 (S11). Next, the discharge purge valve 12b is opened, and the fuel slurry remaining in the pipe on the downstream side of the slurry pump 7 of the upstream slurry supply path 3a is pressure-fed to the slurry tank 1 through the slurry circulation path 4 by process air or high-pressure purge air, The upstream slurry supply passage 3a is purged (S12). At this time, the nozzle purge valve 17b is opened, and the fuel slurry remaining in the pipe at the tip 2b of the slurry injection nozzle 2 is fed under pressure into the furnace 30 by process air to purge the tip 2b of the slurry injection nozzle 2. Thereafter, the discharge purge valve 12b is closed (S13). When purging of the upstream slurry supply passage 3a is completed, the discharge three-way valve 5
Is switched to the middle-stream slurry supply passage 3b and the fuel shut-off valve 6 is opened, and the fuel slurry remaining in the middle-stream slurry supply passage 3b and the slurry injection nozzle 2 is transferred to the upstream slurry supply passage 3a by the furnace pressure in the furnace 30. It moves (S14). After the movement, the discharge three-way valve 5 is switched to the slurry circulation path 4, the pipe purge valve 14b is opened, and the inside of the middle part slurry supply path 3b through the slurry injection nozzle 2 is purged by, for example, high-pressure purge air (S15). Next, the discharge purge valve 1 again
The valve 2b is opened, and the inside of the upstream slurry supply passage 3a on the downstream side of the slurry pump 7 is purged (S16). When the purging of the slurry from the midstream part slurry supply passage 3b to the slurry injection nozzle 2 is completed, the pipe purge valve 14b is closed, and the fuel cutoff valve 6 is closed.
Is closed (S17). Next, the water wetting valve 8b and the drain valve 9b are opened, and the inside of the middle flow part slurry supply passage 3b is washed by flowing water through the middle flow part slurry supply passage 3b (S18). Finally, the discharge purge valve 12b, the nozzle purge valve 17b, the water wetting valve 8b, and the drain valve 9b are closed, and the shutoff purge master process ends (S19). In the fuel nozzle purging step, as shown in FIG. 12, first, the drain valve 9b is opened, the water wetting valve 8b is opened for 10 seconds, and the inside of the middle part slurry supply passage 3b is washed (S2).
1). Next, the water wetting valve 8b and the drain valve 9b are closed, and water is sealed in the pipe of the middle part slurry supply passage 3b (S2).
2). Subsequently, after the pipe purge valve 14b is opened and the backflow prevention purge valve 15b is closed, the fuel shut-off valve 6 is opened for 30 seconds to remove the water sealed in the pipe of the middle part slurry supply passage 3b. Furnace 3 with air from pipe purge valve 14b
0, and the inside of the slurry injection nozzle 2 is washed with water from the downstream slurry supply passage 3c (S23). When the cleaning is completed, the fuel cutoff valve 6 and the pipe purge valve 14b are closed,
The backflow prevention purge valve 15b is opened (S24). next,
The drain valve 9b is opened, and the water wetting valve 8b is opened for 10 seconds to clean the middle part slurry supply passage 3b (S25). Finally, the water wetting valve 8b and the drain valve 9b are closed, and the fuel nozzle purging step is completed (S26).

[0008]

However, the conventional fuel slurry purging method has the following problems. (1) In the shut-off purge step, the fuel slurry remaining in the pipe extending from the middle part slurry supply path 3b to the slurry injection nozzle 2 in the step S14 is fed to the upstream part slurry supply path 3a by the furnace pressure in the furnace 30. Since the fuel slurry has a high viscosity, the middle part slurry supply path 3
A space is formed in the upper part of the pipe, which spreads to the bottom of the pipe from b to the slurry injection nozzle 2 and does not completely move to the upstream slurry supply path 3a, but the bottom part of the pipe from the middle flow part slurry supply path 3b to the slurry injection nozzle 2 And remains.
In such a state, even if air is supplied from the pipe purge valve 14b in the step S15, the air passes through the space formed in the upper part of the pipe from the middle part slurry supply passage 3b to the slurry injection nozzle 2 and passes through the space formed in the upper part of the pipe. The remaining fuel slurry is not purged because it escapes into the furnace. Middle-stream slurry supply path 3
The fuel slurry remaining in b is cleaned in the subsequent step S18, but the slurry remaining in the pipe bottom from the downstream slurry supply passage 3c to the slurry injection nozzle 2 remains as it is. As described above, the downstream slurry supply path 3
The fuel slurry remaining from c to the slurry injection nozzle 2 evaporates moisture due to the heat of the furnace 30 and solidifies. Once consolidated, it is not purged even in the fuel nozzle purging step, which causes a problem that the downstream slurry supply passage 3c and the slurry injection nozzle 2 are filled with fuel slurry.

(2) The fuel slurry has a property that a water component and a solid particle component are easily separated. Therefore, when feeding the fuel slurry into the air-filled pipeline, if the flow velocity of the fuel slurry is low, at the tip of the flow of the fuel slurry,
A solid-liquid separation phenomenon occurs in which the water component of the fuel slurry is separated from the solid particle component. When the solid-liquid separation phenomenon occurs, the fuel slurry that has been concentrated and has a high concentration flows following the water component that flows ahead. As described above, the fuel slurry in which the concentration of the solid particle component is high tends to be filled in the narrow portion of the pipeline. In the conventional fuel slurry purging method, when the fuel slurry first flows into the slurry supply passage 3 at the start of operation, the fuel slurry flows at the input flow rate at the time of initial combustion. However, since the input flow rate at the time of the initial combustion is low, the flow rate of the fuel slurry flowing through the slurry supply path 3 and the slurry injection nozzle 2 becomes slow, so that the solid-liquid separation phenomenon easily occurs.
There has been a problem that the fuel slurry is frequently filled and filled in portions where the pipeline is narrow, such as the b and the dispersion air pipe insertion portion 2c. As described above, when the slurry is filled at the tip 2b of the slurry injection nozzle 2 when the furnace 30 is started, not only does this hinder the automation of the furnace 30 start-up process, but also the tip of the slurry injection nozzle 2 in the furnace 30 can be prevented. There is a problem that the start-up schedule of the furnace 30 is greatly delayed for cleaning to clear the clogging of the portion 2b, and a countermeasure method has been desired.

The fuel slurry supply apparatus according to the present invention solves the above-mentioned conventional problems. When the furnace 30 starts operating, the slurry is not blocked in the pipeline near the tip of the slurry injection nozzle 2 and the furnace When the operation of 30 is stopped,
An object of the present invention is to provide a fuel slurry supply device that can completely purge the fuel slurry in the slurry injection nozzle 2 from the slurry supply passage 3 and does not block the fuel slurry.

The fuel slurry purging method of the present invention solves the above-mentioned conventional problem. When the operation of the furnace 30 is stopped, the fuel slurry in the slurry injection nozzle 2 can be completely purged from the slurry supply passage 3. It is an object of the present invention to provide a method of purging a fuel slurry that is possible and does not block the fuel slurry.

A method of supplying a fuel slurry according to the present invention solves the above-mentioned conventional problem. When the furnace 30 starts operating, the fuel slurry does not block in a pipe near the tip of the slurry injection nozzle 2. It is intended to provide a supply method.

[0013]

In order to solve the above-mentioned problems, a fuel slurry supply device according to the present invention comprises a slurry tank for storing a fuel slurry, a slurry injection nozzle for injecting the fuel slurry into a furnace, and a slurry tank. A slurry supply path communicating with the slurry injection nozzle, a slurry pump disposed in the slurry supply path, a slurry circulation path communicating with the slurry pump downstream of the slurry supply path and the upper part of the slurry tank, a slurry supply path and the slurry; A discharge three-way valve interposed at the connection with the circulation path, a fuel cutoff valve disposed on a slurry supply path downstream of the discharge three-way valve, and a slurry supply passage near a discharge port of the slurry pump; A discharge purge air supply path for supplying purge air to the supply path, a discharge purge valve disposed in the discharge purge air supply path, and a slurry supply path near a downstream opening of the discharge three-way valve. A pipe purge valve provided in a flow-section purge air supply path, a pipe purge valve provided in a middle-stream section purge air supply path, a water supply path communicating with a slurry supply path near an upstream opening of a fuel cutoff valve, and water provided in a water supply path. A fuel slurry supply device comprising: a wetting valve; a drainage passage communicating with a slurry supply passage near a downstream opening of a discharge three-way valve; and a drainage valve disposed in the drainage passage. At the time of stop, the slurry pump is stopped, the fuel cutoff valve is closed, the discharge three-way valve is operated so that the slurry supply path upstream of the discharge three-way valve communicates with the slurry circulation path, and then the discharge purge valve is opened. The fuel slurry remaining in the slurry supply path on the upstream side of the valve discharge three-way valve is purged with purge air, the pipe purge valve is opened, and the slurry supply path between the discharge three-way valve and the fuel cutoff valve is pressurized with purge air, Open the fuel cutoff valve and discharge The fuel slurry remaining in the slurry supply path downstream of the three-way valve is pushed into the furnace, purged, the fuel cutoff valve is closed, the pipe purge valve is closed, the water wetting valve and the drain valve are opened, and the discharge three-way valve and the fuel are discharged. Water is passed through the slurry supply path between the shut-off valve, the water wetting valve and the drain valve are closed, and water is sealed in the slurry supply path between the discharge three-way valve and the fuel cut-off valve. It comprises a control means for controlling the opening of the shut-off valve. With this configuration, at the start of the operation of the furnace 30, the slurry is not blocked in the pipeline near the tip of the slurry injection nozzle 2,
When the operation of the furnace 30 is stopped, the fuel slurry in the slurry injection nozzle 2 can be completely purged from the slurry supply path 3 and a fuel slurry supply device that does not block the fuel slurry can be provided.

According to another aspect of the present invention, there is provided a fuel slurry purging method, comprising: a slurry tank for storing a fuel slurry; a slurry injection nozzle for injecting the fuel slurry into a furnace; a slurry tank and a slurry injection nozzle; A slurry supply path communicating with the slurry supply path, a slurry pump disposed in the slurry supply path, a slurry circulation path communicating with the slurry pump downstream of the slurry supply path and the upper part of the slurry tank, a slurry supply path and a slurry circulation path. A fuel slurry purging method in a fuel slurry supply device, comprising: a discharge three-way valve interposed at a connection portion of the fuel supply device; and a fuel cutoff valve disposed in a slurry supply passage downstream of the discharge three-way valve. When the supply of the fuel slurry is stopped, the slurry pump is stopped, the fuel cutoff valve is closed, and the discharge three-way valve communicates with the slurry supply passage upstream of the discharge three-way valve and the slurry circulation passage. After the operation, the fuel slurry remaining in the slurry supply path on the upstream side of the discharge three-way valve is purged by purge air, and the fuel is supplied while the slurry supply path between the discharge three-way valve and the fuel cutoff valve is pressurized by the purge air. By opening the shut-off valve, the fuel slurry remaining in the slurry supply path on the downstream side of the discharge three-way valve is pushed into the furnace and purged, and thereafter, from the slurry supply path on the downstream side of the discharge three-way valve to the tip of the slurry injection nozzle. Is washed. Thus, when the operation of the furnace 30 is stopped, it is possible to completely purge the fuel slurry in the slurry injection nozzle 2 from the slurry supply path 3 and to provide a fuel slurry purging method without blocking the fuel slurry. Can be.

According to another aspect of the present invention, there is provided a fuel slurry supply method comprising: a slurry tank for storing a fuel slurry; a slurry injection nozzle for injecting the fuel slurry into a furnace; a slurry tank and a slurry injection nozzle; A fuel slurry supply method in a fuel slurry supply device comprising: a slurry supply passage communicating with the fuel supply passage; and a slurry pump disposed in the slurry supply passage. Until the fuel passes through the tip of the slurry injection nozzle, the flow rate of the fuel slurry is larger than the initial input amount of the fuel slurry, and is smaller than the flow rate at which the properties of the fuel slurry in the slurry injection nozzle change. After the tip of the fuel slurry flows through the tip of the slurry injection nozzle, the flow rate of the fuel And wherein reducing the output of the slurry pump until the input amount. Thereby, the furnace 3
At the start of operation 0, a fuel slurry supply method can be provided that does not block the slurry in the pipeline near the tip of the slurry injection nozzle 2.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In order to achieve this object, a fuel slurry supply apparatus according to a first aspect of the present invention comprises a slurry tank for storing a fuel slurry, a slurry injection nozzle for injecting the fuel slurry into a furnace, and a fuel tank. A slurry supply path communicating with the slurry tank and the slurry injection nozzle, a slurry pump disposed in the slurry supply path, and a slurry circulation path communicating with the slurry pump downstream of the slurry supply path and the upper part of the slurry tank;
A discharge three-way valve interposed at the connection between the slurry supply path and the slurry circulation path, a fuel cutoff valve disposed in a slurry supply path downstream of the discharge three-way valve, and a slurry supply near the discharge port of the slurry pump. A discharge purge air supply path for supplying purge air to the slurry supply path in communication with the flow path, a discharge purge valve disposed in the discharge purge air supply path, and a middle part communicating with a slurry supply path near a downstream opening of the discharge three-way valve. A purge air supply path,
A pipe purge valve disposed in the midstream purge air supply path,
A water supply passage communicating with a slurry supply passage near the upstream opening of the fuel cutoff valve, a water wetting valve disposed in the water supply passage, and a drainage passage communicating with the slurry supply passage near the downstream opening of the discharge three-way valve. And a drain valve disposed in a drain passage, wherein when the supply of the fuel slurry is stopped, the slurry pump is stopped, the fuel cutoff valve is closed, and the discharge three-way valve is discharged. After operating so that the slurry supply path on the upstream side of the three-way valve communicates with the slurry circulation path, the discharge purge valve is opened and the fuel slurry remaining in the slurry supply path on the upstream side of the discharge three-way valve is purged with purge air. The piping purge valve is opened, the slurry supply passage between the discharge three-way valve and the fuel cutoff valve is pressurized by purge air, the fuel cutoff valve is opened, and the fuel slurry remaining in the slurry supply passage downstream of the discharge three-way valve is opened. Into the furnace and purge. Close the shutoff valve, close the pipe purge valve, open the water wetting valve and drain valve, pass water through the slurry supply path between the discharge three-way valve and the fuel shutoff valve, and close the water wetting valve and drain valve. And a control means for controlling the opening of the pipe purge valve and the fuel cutoff valve by sealing water in the slurry supply passage between the three-way discharge valve and the fuel cutoff valve. Thus, after the supply of the fuel slurry is stopped, the slurry remaining in the slurry supply path can be completely purged. The fuel slurry is prevented from remaining in the slurry supply path and solidifying to block the slurry supply path. Is obtained.

Here, when a plurality of sets of the slurry injection nozzle and the slurry supply system for supplying the fuel slurry to the slurry injection nozzle are provided, the control performed by the control unit is to stop the slurry pump, and then perform the control on the downstream side of the discharge three-way valve. Steps until the fuel slurry remaining in the slurry supply path is pushed into the furnace and purged (hereinafter, referred to as a first step) are sequentially performed for all the slurry injection nozzles, and then the subsequent steps (hereinafter, referred to as a second step). ) In order for all the slurry injection nozzles. A control in which the first step and the second step are sequentially performed for all the slurry injection nozzles. A control in which the pre-stage and post-stage processes are simultaneously performed for all the slurry injection nozzles. And so on.

A fuel slurry supply device according to a second aspect of the present invention communicates with a slurry tank for storing a fuel slurry, a slurry injection nozzle for injecting the fuel slurry into a furnace, and a slurry tank and a slurry injection nozzle. A slurry supply channel,
And a slurry pump provided in the slurry supply path, wherein at the start of fuel slurry supply, until the leading end of the fuel slurry flow passes through the leading end of the slurry injection nozzle, The output of the slurry pump is controlled so that the flow rate of the fuel slurry is larger than the initial input amount of the fuel slurry and smaller than the flow rate at which the properties of the fuel slurry in the slurry injection nozzle change, and the tip of the flow of the fuel slurry flows. After passing through the tip of the slurry injection nozzle, the configuration is provided with control means for performing control to reduce the output of the slurry pump until the flow rate of the fuel slurry becomes the initial input amount of the fuel slurry. When the supply of the fuel slurry is started, the fuel slurry does not separate into the water component and the particle component, and the fuel slurry fills the tip of the slurry injection nozzle. Effect of but is prevented is obtained.

As the flow rate of the fuel slurry in the slurry supply pipe increases, the liquid component filled between the solid particles of the fuel slurry is extruded and separated, and the liquid component flows before the solid particle component. Since the water running phenomenon occurs, the solid particle components are concentrated, and the properties of the fuel slurry change.
"The flow rate at which the properties of the fuel slurry in the slurry injection nozzle changes" refers to the flow rate at which the properties of the fuel slurry change due to the water running phenomenon described above. It is an amount that depends on it.

According to a third aspect of the present invention, there is provided a fuel slurry purging method, wherein the slurry tank stores the fuel slurry, the slurry injection nozzle injects the fuel slurry into the furnace, and the slurry tank and the slurry injection nozzle communicate with each other. Slurry supply path, a slurry pump disposed in the slurry supply path, a slurry circulation path communicating with the slurry pump downstream of the slurry supply path and the upper part of the slurry tank, and a connecting portion between the slurry supply path and the slurry circulation path. And a fuel shut-off valve disposed in a slurry supply passage downstream of the discharge three-way valve. When the supply was stopped, the slurry pump was stopped, the fuel cutoff valve was closed, and the discharge three-way valve was operated so that the slurry supply path on the upstream side of the discharge three-way valve and the slurry circulation path were connected. The fuel slurry remaining on the upstream side slurry supply passage of the discharge three-way valve is purged with purge air,
By opening the fuel cutoff valve in a state where the slurry supply passage between the discharge three-way valve and the fuel cutoff valve is pressurized by the purge air, fuel slurry remaining in the slurry supply passage downstream of the discharge three-way valve is removed from the furnace. After that, after the supply of the fuel slurry is stopped, the slurry is cleaned by cleaning from the slurry supply path on the downstream side of the discharge three-way valve to the tip of the slurry injection nozzle. The slurry remaining in the supply path can be completely purged. The fuel slurry is prevented from remaining in the slurry supply path and solidifying to block the slurry supply path. Is obtained.

According to a fourth aspect of the present invention, there is provided a fuel slurry supply method, wherein a slurry tank for storing a fuel slurry, a slurry injection nozzle for injecting the fuel slurry into a furnace, and a slurry tank and a slurry injection nozzle are communicated. A slurry supply channel,
A slurry pump provided in a slurry supply path, and a fuel slurry supply method in a fuel slurry supply device, comprising: Until the fuel slurry passes, the output of the slurry pump is controlled so that the flow rate of the fuel slurry is higher than the initial input amount of the fuel slurry and lower than the flow rate at which the property of the fuel slurry in the slurry injection nozzle changes. After the tip of the flow of the fuel has passed through the tip of the slurry injection nozzle, the output of the slurry pump is reduced until the flow rate of the fuel slurry becomes equal to the initial input amount of the fuel slurry. At the start of slurry supply, the fuel slurry does not separate into water and particle components, and the fuel slurry fills the tip of the slurry injection nozzle. Effect of but is prevented is obtained.

An embodiment of the present invention will be described below with reference to the drawings. (Embodiment 1) FIG. 1 is a configuration diagram showing a fuel slurry supply apparatus according to Embodiment 1 of the present invention. In FIG. 1, reference numeral 1 denotes a slurry tank for storing a fuel slurry, 2 denotes a tubular slurry injection nozzle which supplies a fuel slurry from a tapered tip 2b into a furnace 30 of a pressurized fluidized-bed boiler, and 2a denotes a tubular slurry injection nozzle. Dispersed air pipe 2a is disposed concentrically in the pipeline of the slurry injection nozzle 2 and has a tip 2b opening near the tip 2b of the slurry injection nozzle 2; Dispersed air insertion part, 3
a is an upstream slurry supply passage whose upstream end communicates with the lower portion of the slurry tank 1; 3b is a middle flow slurry supply passage whose upstream end communicates with the downstream end of the upstream slurry supply passage 3a;
Reference numeral c denotes a downstream slurry supply passage whose upstream end communicates with the downstream end of the middle flow slurry supply passage 3b and whose downstream end communicates with the slurry injection nozzle 2. The fuel slurry stored in the slurry tank 1 is supplied to the slurry injection nozzle 2 through the upstream slurry supply passage 3a, the middle slurry supply passage 3b, and the downstream slurry supply passage 3c, and is injected into the furnace 30. . 4
Is a slurry circulation path having one end communicating with a connection between the upstream slurry supply path 3a and the middle flow slurry supply path 3b and the other end communicating with the upper part of the slurry tank 1. Reference numeral 5 denotes an upstream slurry supply path 3a and the middle slurry. A three-way discharge valve interposed at the junction between the supply path 3b and the slurry circulation path 4, and a fuel 6 composed of an on-off valve interposed at the junction between the midstream slurry supply path 3b and the downstream slurry supply path 3c The shut-off valve 7 is a slurry pump provided in the upstream slurry supply passage 3a. The discharge three-way valve 5 connects the upstream slurry supply passage 3a to the middle flow slurry supply passage 3b or the slurry circulation passage 4 so as to be freely switchable. Reference numeral 8 denotes a water supply passage which communicates with the vicinity of the downstream end of the midstream slurry supply passage 3b to supply water to the midstream slurry supply passage 3b, reference numeral 8b denotes a water wetting valve comprising an open / close valve provided in the water supply passage 8, Reference numeral 9 denotes a drainage passage communicating with the vicinity of the upstream end of the middle-stream slurry supply passage 3b, and reference numeral 9b denotes a drainage valve including an open / close valve disposed in the drainage passage 9. Reference numeral 10 denotes an upstream purge air supply path for supplying purge air for purging the inside of the upstream slurry supply path 3 a and the slurry circulation path 4, and reference numeral 11 denotes a connection between the upstream purge air supply path 10 and the discharge three-way valve 5 of the slurry circulation path 4. A circulation purge air supply passage communicating with the vicinity of the joining portion; 11b, a circulation purge valve including an open / close valve disposed on the circulation purge air supply passage 11; 12: a slurry pump for the upstream purge air supply passage 10 and the upstream slurry supply passage 3a A discharge purge air supply passage 12b communicating with the vicinity of the discharge port 7 is a discharge purge valve including an open / close valve disposed in the discharge purge air supply passage 12. 13 is a process air supply passage for supplying process air, 14 is a middle flow purge air supply passage communicating with the process air supply passage 13 and near the upstream end of the middle flow slurry supply passage 3b, and 14b is a middle flow purge air supply passage 14. A pipe purge valve composed of an on-off valve disposed near the junction with the slurry supply passage 3b in the middle stream, 14
c is a pipe purge valve 14b of the midstream purge air supply path 14.
A check valve 15 disposed upstream of the downstream purge air supply passage 15 communicates with the process air supply passage 13 near the upstream end of the downstream slurry supply passage 3c. A backflow prevention purge valve 15 comprising an on-off valve disposed near the junction with the downstream slurry supply passage 3c;
c is a backflow prevention purge valve 1 of the downstream purge air supply passage 15.
A check valve arranged upstream of 5b, a fuel dispersion air supply path 16 communicating with the process air supply path 13 and the dispersion air pipe 2a, and a fuel dispersion air supply path 16b arranged in the fuel dispersion air supply path 16 The air control valve 16c is a fuel distribution air supply passage 16
A check valve 17 disposed downstream of the fuel-dispersed air control valve 16b; a nozzle purge air supply 17 communicating with the downstream of the fuel-dispersed air supply passage 16c of the fuel-dispersed air supply passage 16 and the process air supply passage 13; A passage 17b is a nozzle purge valve composed of an open / close valve disposed in the nozzle purge air supply passage 17, and a reference numeral 17c is a check valve disposed upstream of the nozzle purge valve 17b in the nozzle purge air supply passage 17. Reference numeral 18 denotes a high-pressure purge air supply path for supplying high-pressure purge air.
b is a high-pressure purge source valve arranged in the high-pressure air supply path 18,
Reference numeral 19 denotes a pipe purge valve 14 of the midstream purge air supply passage 14.
b, a middle-stream high-pressure purge air supply passage communicating with an intermediate portion between the b and the middle-stream purge air supply passage 14c and a downstream end of the high-pressure air supply passage 18;
A check valve 20 provided at 9 is a nozzle high-pressure purge air supply communicating with an intermediate portion between the nozzle purge valve 17b and the nozzle purge air supply passage 17c of the nozzle purge air supply passage 17 and a downstream end of the high-pressure air supply passage 18. The passage 20 c is a check valve disposed in the nozzle high-pressure purge air supply passage 20.

The operation of the fuel slurry supply apparatus having the above-described configuration when the fuel slurry is supplied and started in the fuel slurry supply method according to the first embodiment will be described below with reference to the drawings. FIG. 2 is a flowchart showing the operation of the fuel slurry supply method according to Embodiment 1 at the time of starting the pressurized fluidized-bed boiler, FIG. 3 is a flowchart of the high-pressure purge step, and FIG. 4 is a flowchart of the fuel slurry charging step. FIG. 5 is a diagram showing the flow control of the fuel slurry in the fuel slurry charging step. As an initial state, in an operation stop state of the fluidized bed boiler, the discharge three-way valve 5 is connected to the slurry circulation path 4, the fuel cutoff valve 6 is closed, and the pipe purge valve 14b is closed. The water wetting valve 8b and the drain valve 9b are closed, the circulation purge valve 11b and the discharge purge valve 12b are closed, and the high-pressure purge source valve 18b is closed. The backflow prevention purge valve 15b and the fuel dispersion air control valve 16b are opened, and process air flows into the furnace 30 from the downstream purge air supply passage 15 and the fuel dispersion air supply passage 16. When the operation is started, first, the slurry pump 7 is started, and the slurry is supplied from the slurry tank 1 to the upstream slurry supply path 3.
a, Circulate through the slurry circulation path 4 to the slurry tank 1 (S30). Thereby, the slurry in the slurry tank 1 is stirred, and the particles in the slurry and water are mixed. Further, the discharge flow rate of the slurry pump 7 at this time is Q _2.
Next, the gas turbine 34 is started (S31), and a high-pressure purge step is performed to check whether the slurry injection nozzle 2 is clogged (S32). Next, light oil is burned in the furnace 30 to raise the temperature inside the furnace 30 (S33), and the fuel nozzle purge step is performed twice (S34). Next, after waiting until the furnace temperature of the furnace 30 becomes 600 ° C. or higher (S3
5) A fuel slurry charging step is performed (S36), and the furnace 30
Startup is completed.

Here, the high pressure purging step is performed according to the flowchart of FIG. First, the high pressure purge source valve 18
b, the nozzle purge valve 17b is opened, and the pipe purge valve 14b is opened. Then, the fuel cutoff valve 6 is opened for 30 seconds, and the tip 2b of the slurry injection nozzle 2 from the middle flow slurry supply passage 3b. High-pressure purge air is supplied during (S3
7). This purges from the middle-stream slurry supply passage 3b to the tip 2b of the slurry injection nozzle 2 with high-pressure purge air, and measures a pressure difference between the pressure in the furnace 30 and the middle-stream slurry supply passage 3b with a pressure gauge (FIG. (Not shown), the clogging of the fuel slurry between the slurry supply nozzle 3 from the middle-stream slurry supply passage 3b and the slurry injection nozzle 2 is detected. next,
After closing the fuel cutoff valve 6, closing the pipe purge valve 14b, the nozzle purge valve 17b, and the high pressure purge source valve 18b to stop the supply of the high pressure purge air into the slurry supply pipe 3,
The residual pressure is released by opening and closing the drain valve 9b (S38).
Complete the high pressure purge step.

The fuel slurry charging step is performed according to the flowchart of FIG. In the initial state of the fuel slurry charging step, the slurry supply path 3
a, The fuel slurry is circulated through the slurry circulation path 4 at a flow rate Q ₂ and is stirred. In this state, first,
The water wetting valve 8b and the drain valve 9b are opened, water is supplied from the water supply channel 8 to the drain channel 9 through the middle flow slurry supply channel 3b, and water is filled in the pipe of the middle flow slurry supply channel 3b (S4).
1). Thereafter, the water wetting valve 8b and the drain valve 9b are closed, and the water is sealed in the middle part slurry supply passage 3b (S4).
2). Next, the backflow prevention purge valve 15b is closed, the process air flowing to the downstream slurry supply passage 3c and the slurry injection nozzle 2 is stopped, and then the fuel cutoff valve 6 is opened to seal the middle flow slurry supply passage 3b. The discharged water flows out into the downstream part slurry supply path 3c and the slurry injection nozzle 2, and flows from the middle part slurry supply path 3b to the tip part 2 of the slurry injection nozzle 2.
b) (S43), the fuel shut-off valve 6
Is closed (S44). Thereby, the middle part slurry supply path 3b, the downstream part slurry supply path 3c, the slurry injection nozzle 2
A lubricating film of water is formed on the inner wall surface of the pipe to reduce friction when passing through the fuel slurry, and the solid-liquid separation phenomenon hardly occurs. Further, the steps from S41 to S44 may be repeated a plurality of times until the part from the middle-stream slurry supply passage 3b to the tip 2b of the slurry injection nozzle 2 is completely wetted. Next, the water wetting valve 8b and the drain valve 9b are opened again, and water is passed from the water supply channel 8 to the drain channel 9 through the middle-stream slurry supply channel 3b (S45). Thereafter, the water wetting valve 8b and the drain valve 9b are closed again, and water is sealed in the middle part slurry supply passage 3b (S46). Next, the discharge three-way valve 5 is switched to the middle part slurry supply path 3b, and immediately after that, the fuel cutoff valve 6 is opened, and the fuel slurry is transferred from the slurry tank 1 to the upstream part slurry supply path 3a, the middle part slurry supply path 3b, The slurry flows to the slurry injection nozzle 2 through the downstream slurry supply passage 3 c, and the fuel slurry is injected into the furnace 30 from the tip of the slurry injection nozzle 2.
At this time, in the water filling process, the middle part slurry supply passage 3b
The water sealed in the pipe flows ahead of the fuel slurry and flows through the pipeline of the middle-stream slurry supply passage 3b, the downstream slurry supply passage 3c, and the slurry injection nozzle 2, whereby the surface of the pipeline inner wall is lubricated with water again. This reduces friction in the pipeline when passing through the fuel slurry. At this time, the circulation purge valve 11b is opened, purge air is supplied to the slurry circulation path 4, and the fuel slurry in the slurry circulation path 4 is purged to the slurry tank 1 (S
47). Tip 2b of slurry injection nozzle 2 for fuel slurry
From immediately after the injection into the furnace 30 is started, reducing the discharge flow rate of the slurry pump 7 to put the flow rate to Q ₁ during initial combustion.

At this time, the discharge flow rate of the slurry pump 7 is
As shown in FIG. 5, in steps S40 to S47,
Is constant flow Q_TwoAnd the start time of the step S47
t₁38-44 seconds after, in step S48, slurry injection
Fuel slurry is injected into the furnace 30 from the tip of the nozzle 2.
Time t_TwoImmediately thereafter, the output of the slurry pump 7 is reduced.
Then, time t_Three, The discharge flow rate of the slurry pump 7
Is the input flow rate Q during initial combustion₁, And then the next operation
Until is performed, a constant value is taken. Flow Q_Twoof
The value should be more than the initial amount of fuel slurry.
From the flow rate at which the properties of the fuel slurry in the injection nozzle 2 change
Is low, but the initial flow rate of the fuel slurry
The flow rate is preferably 2 to 10 times the flow rate. Flow
The speed is more than twice the speed at which the solid-liquid separation of the fuel slurry occurs.
As the size becomes smaller, the solid-liquid separation phenomenon easily occurs.
More than two times, the space between the solid particles of the fuel slurry
Filled liquid components are extruded by external pressure and separated,
A water running phenomenon occurs where the component flows before the solid particle component.
And the solid particles are concentrated, changing the properties of the fuel slurry
Because you do. A specific example is a fuel slurry.
The CWM concentration is 65-75 w% and the particle size is less than 45 μm.
When the solid particle component of the fuel slurry is 17 to 23 w%, Q
_Two= 4t / h, Q₁= 1 t / h is preferred. Ma
At this time, t _Two~ T_ThreeDischarge with a time constant of 7 seconds
Decrease flow rate. Thereby, in step S47,
The solid-liquid separation phenomenon is prevented, and the fuel slurry
The tip 2b of the injection nozzle 2, the dispersing air pipe insertion part 2c, etc.
Of the pipe is blocked in the narrow part of the pipe, and the pipe is blocked
Is prevented. Finally, the fuel switch in the slurry circulation path 4
When the slurry is completely purged into the slurry tank 1, the circulation
The purge valve 11b is closed and the purge air flowing through the slurry circulation path 4 is closed.
And the operation at the start of fuel slurry injection is completed (S
49).

Next, the operation of the fuel slurry purging method according to Embodiment 1 when the operation is stopped will be described with reference to the drawings.

FIG. 6 is a flowchart showing the operation of the fuel slurry purging method according to the first embodiment when the operation is stopped.
FIG. 7 is a flowchart showing the pushing purge process. In the normal operation state, the discharge three-way valve 5 is connected to the middle part slurry supply passage 3.
b, the fuel cutoff valve 6 is opened,
The fuel slurry is supplied from the slurry tank 1 by the slurry pump 7 to the upstream slurry supply passage 3a, the middle slurry supply passage 3b,
The slurry is supplied to the furnace 30 from the tip of the slurry injection nozzle 2 through the downstream slurry supply path 3c and the slurry injection nozzle 2. Further, a pipe purge valve 14b, a backflow prevention purge valve 15b, a nozzle purge valve 17b, a high pressure purge source valve 18b
Is closed, the fuel distribution air control valve 16b is opened, and the process air is supplied to the fuel distribution air supply passage 16,
The tip 2 of the slurry injection nozzle 2 through the dispersion air pipe 2a
b and is injected into the furnace 30 together with the fuel slurry. The water wetting valve 8b, the drain valve 9b, the circulation purge valve 11b, and the discharge purge valve 12b are closed.
When stopping the operation, as shown in FIG. 6, first, a push-in purging step is executed (S50). After the completion of the indentation purge step, a fuel nozzle purge step is performed, the fuel cutoff valve 6 and the pipe purge valve 14b are opened, and high-pressure purge air or process air and water are used to feed the middle part slurry supply passage 3b to the pipeline of the slurry injection nozzle 2. The residual fuel slurry is purged into the furnace 30 (S51). Here, the fuel nozzle purging step is the same as that in FIG. Next, the bed height is lowered until the bed height of the fluidized bed in the furnace 30 becomes 0.2 m or less (S52), and finally, the gas turbine 34 is stopped (S53).

Here, the pushing purge process shown in FIG. 7 is executed as follows. First, the slurry pump 7 is stopped to stop the flow of the fuel slurry (S60), the three-way discharge valve 5 is switched to the slurry circulation path 4, and the fuel cutoff valve 6 is closed (S60).
61). Next, by opening the discharge purge valve 12b and feeding the purge air into the upstream slurry supply passage 3a, the fuel slurry sealed in the upstream slurry supply passage 3a is pushed out to the slurry circulation passage 4, and extended. Purge into slurry tank 1. At this time, the nozzle purge valve 17b is opened to purge the tip 2b of the slurry injection nozzle 2 (S62). Next, the pipe purge valve 14b is opened, and process air is fed into the middle part slurry supply passage 3b.
The fuel slurry inside is pressurized (S63). Next, the fuel cutoff valve 6 is opened for 10 seconds, and process air is fed from the middle-stream purge air supply passage 14 to the middle-stream slurry supply passage 3b.
The fuel slurry remaining in the middle-stream slurry supply passage 3b pressurized in the 63 step is pressure-fed into the furnace 30 at a stretch by process air. At this time, the downstream slurry supply path 3c
The remaining fuel slurry from the nozzle to the slurry injection nozzle 2 is also pumped into the furnace 30 (S64). When the fuel slurry remaining in the middle part slurry supply path 3b in the step S64 is pressure-fed to near the tip of the slurry injection nozzle 2, the high pressure purge source valve 18b is opened for three seconds, and the middle part slurry supply path 3b and the dispersion are dispersed. The high-pressure purge air is fed into the air pipe 2a, and the fuel slurry that has not been completely purged in the pushing purge step and has remained in the middle-stream slurry supply path 3b and the pipeline of the slurry injection nozzle 2 is blown into the furnace 30 by the high-pressure purge air. (S65). At this time, in step S64, a method of purging by supplying high-pressure purge air from the beginning is also conceivable. In this case, the fuel slurry is pressure-fed into the furnace 30 at high speed, and the fuel slurry is supplied to the inner wall of the furnace 30 facing the slurry injection nozzle 2. It is not preferable because it may collide and damage the inner wall of the furnace 30. Next, the fuel cutoff valve 6 is closed, and the flow of the high-pressure air from the slurry supply passage 3b in the middle part to the slurry injection nozzle 2 is stopped. Further, the high pressure purge source valve 18b is closed, the flow of the high pressure purge air flowing to the distribution air pipe 2a is stopped, and the pipe purge valve 14b is closed. At this time, the pressure of the high-pressure purge air remains in the pipeline of the middle-stream slurry supply passage 3b (S6).
6). Next, the drain valve 9b is opened, and the residual pressure in the pipeline of the middle part slurry supply passage 3b is released through the drain passage 9. Thereafter, the backflow prevention purge valve 15b is opened, and process air is fed into the downstream slurry supply passage 3c (S67). next,
Discharge purge valve 12b, nozzle purge valve 17b, drain valve 9
b is closed (S68), and the pushing purge process is completed.

[0030]

As described above, according to the fuel slurry supply device of the first aspect, a slurry tank for storing the fuel slurry, a slurry injection nozzle for injecting the fuel slurry into the furnace, a slurry tank and the slurry injection. A slurry supply path communicating with the nozzle, a slurry pump disposed in the slurry supply path, a slurry circulation path communicating with the slurry pump downstream of the slurry supply path and the upper part of the slurry tank, a slurry supply path and a slurry circulation path A three-way discharge valve interposed at the connection with the fuel supply valve, a fuel cutoff valve disposed in a slurry supply path downstream of the three-way discharge valve, and a slurry supply path communicating with a slurry supply path near the discharge port of the slurry pump. Purge air supply passage for supplying purge air to the discharge passage, a discharge purge valve disposed in the discharge purge air supply passage, and a middle flow purge communicating with a slurry supply passage near the downstream opening of the discharge three-way valve. (A) a supply path, a pipe purge valve disposed in a middle-stream purge air supply path, a water supply path communicating with a slurry supply path near an upstream opening of the fuel cutoff valve, and a water wetting valve disposed in the water supply path. And a drainage passage communicating with the slurry supply passage near the downstream opening of the discharge three-way valve, and a drainage valve disposed in the drainage passage, wherein when the supply of the fuel slurry is stopped, In, the slurry pump is stopped, the fuel cutoff valve is closed, and the discharge three-way valve is operated so that the slurry supply path on the upstream side of the discharge three-way valve communicates with the slurry circulation path, and then the discharge purge valve is opened. The fuel slurry remaining in the slurry supply path on the upstream side of the discharge three-way valve is purged with purge air, the pipe purge valve is opened, and the slurry supply path between the discharge three-way valve and the fuel cutoff valve is pressurized with purge air to shut off the fuel. Open the valve and under the three-way discharge valve The fuel slurry remaining in the slurry supply passage on the side is pushed into the furnace, purged, the fuel shutoff valve is closed, the pipe purge valve is closed, the water wetting valve and the drain valve are opened, and the discharge three-way valve and the fuel shutoff valve are closed. Water is passed through the slurry supply path, the water wetting valve and the drain valve are closed, water is sealed in the slurry supply path between the discharge three-way valve and the fuel cutoff valve, and the pipe purge valve and the fuel cutoff valve are opened. The provision of the control means for performing valve control makes it possible to provide a fuel slurry supply device in which the slurry supply path is not blocked by the fuel slurry remaining in the slurry supply path after the supply of the fuel slurry is stopped. . Since the fuel slurry is not blocked, the operation of removing the slurry in the slurry injection nozzle becomes unnecessary, and it is possible to provide a fuel slurry supply device capable of remarkably reducing the number of man-hours and the number of working days in operation and maintenance. It becomes possible. No nozzle cleaning is required, and a quick restart operation (for example, DSS, WES) of the plant becomes possible, and the operability of the plant is improved. The advantageous effect described above can be obtained.

According to the fuel slurry supply device of the present invention, a slurry tank for storing the fuel slurry, a slurry injection nozzle for injecting the fuel slurry into the furnace, and a slurry communicating with the slurry tank and the slurry injection nozzle. A fuel slurry supply device including a supply path and a slurry pump disposed in the slurry supply path, wherein at the start of supply of the fuel slurry, the leading end of the fuel slurry flow passes through the leading end of the slurry injection nozzle. Until that time, the output of the slurry pump is controlled so that the flow rate of the fuel slurry is lower than the flow rate at which the properties of the fuel slurry in the slurry injection nozzle are larger than the initial input amount of the fuel slurry. After the end of the flow passes through the tip of the slurry injection nozzle, reduce the output of the slurry pump until the fuel slurry flow rate reaches the initial amount of fuel slurry By having a control unit that performs control to, at the start the supply of the fuel slurry, the fuel slurry is prevented from Hama塞 the slurry injection nozzle tip. Since the fuel slurry is not blocked, the operation of removing the slurry in the slurry injection nozzle becomes unnecessary, and it is possible to provide a fuel slurry supply device capable of remarkably reducing the number of man-hours and the number of working days in operation and maintenance. It becomes possible. The advantageous effect described above can be obtained.

According to the fuel slurry purging method of the third aspect, the slurry tank for storing the fuel slurry, the slurry injection nozzle for injecting the fuel slurry into the furnace, and the slurry tank and the slurry injection nozzle are communicated. A slurry supply path, a slurry pump disposed in the slurry supply path, a slurry circulation path communicating with the slurry pump downstream of the slurry supply path and the upper part of the slurry tank, and a connecting portion between the slurry supply path and the slurry circulation path. A method for purging a fuel slurry in a fuel slurry supply device comprising: an interposed discharge three-way valve; and a fuel cut-off valve disposed in a slurry supply passage downstream of the discharge three-way valve, comprising: After stopping, the slurry pump is stopped, the fuel cutoff valve is closed, and the discharge three-way valve is operated so that the slurry supply path on the upstream side of the discharge three-way valve communicates with the slurry circulation path. Fuel slurry remaining on the upstream side slurry supply passage of the discharge three-way valve is purged with purge air,
By opening the fuel cutoff valve in a state where the slurry supply passage between the discharge three-way valve and the fuel cutoff valve is pressurized by the purge air, fuel slurry remaining in the slurry supply passage downstream of the discharge three-way valve is removed from the furnace. Then, the slurry from the slurry supply path on the downstream side of the discharge three-way valve to the tip of the slurry injection nozzle is washed, so that the slurry supply path is blocked by the fuel slurry remaining in the slurry supply path after the supply of the fuel slurry is stopped. Thus, it is possible to provide a method of purging a fuel slurry that does not occur. Since the fuel slurry is not blocked, the number of man-hours and the number of working days in operation and maintenance are significantly reduced. The advantageous effect described above can be obtained.

According to the fuel slurry supply method of the fourth aspect, a slurry tank for storing the fuel slurry, a slurry injection nozzle for injecting the fuel slurry into the furnace, and a slurry communicating with the slurry tank and the slurry injection nozzle. A fuel slurry supply method in a fuel slurry supply device including a supply path and a slurry pump disposed in the slurry supply path,
At the start of the supply of the fuel slurry, the flow rate of the fuel slurry is larger than the initial amount of the fuel slurry until the leading end of the fuel slurry flow passes through the leading end of the slurry injection nozzle. Control the output of the slurry pump so that the flow rate is smaller than the flow rate at which the fuel slurry changes, and after the tip of the fuel slurry flow passes through the tip of the slurry injection nozzle, the flow rate of the fuel By reducing the output of the slurry pump to the extent possible, it is possible to provide a fuel slurry supply method in which the fuel slurry does not block the tip of the slurry injection nozzle at the start of fuel slurry supply. Since the fuel slurry does not block the tip of the slurry injection nozzle, the operation at the start of the supply of the fuel slurry can be automated. Since the fuel slurry is not blocked, the number of man-hours and the number of working days in operation and maintenance are significantly reduced. The advantageous effect described above can be obtained.

[Brief description of the drawings]

FIG. 1 is a configuration diagram illustrating a fuel slurry supply device according to a first embodiment of the present invention.

FIG. 2 is a flowchart showing the operation of the fuel slurry supply method according to the first embodiment when the pressurized fluidized-bed boiler is started.

FIG. 3 is a flowchart of a high-pressure purge step.

FIG. 4 is a flowchart of a fuel slurry charging step.

FIG. 5 is a diagram showing flow control of a fuel slurry in a fuel slurry charging step.

FIG. 6 is a flowchart illustrating an operation of the fuel slurry purging method according to the first embodiment when operation is stopped.

FIG. 7 is a flowchart showing a pushing purge process.

FIG. 8 is a configuration diagram showing an example of a pressurized fluidized-bed boiler.

FIG. 9 is a configuration diagram showing an example of a fuel slurry supply device for performing the fuel slurry purging method disclosed in Japanese Patent Publication No.

FIG. 10 is a flowchart showing a conventional fuel slurry purging method when the operation of a pressurized fluidized bed boiler is stopped.

FIG. 11 is a flowchart showing a shut-off purge process.

FIG. 12 is a flowchart showing a fuel nozzle purging process.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Slurry tank 2 Slurry injection nozzle 2a Dispersed air pipe 2b Tip 2c Dispersed air pipe insertion part 3 Slurry supply path 3a Upstream part slurry supply path 3b Midstream part slurry supply path 3c Downstream part slurry supply path 4 Slurry circulation path 5 Discharge three-way valve Reference Signs List 6 fuel cutoff valve 7 slurry pump 8 water supply path 8b water wetting valve 8c check valve 9 drainage path 9b drainage valve 10 upstream purge air supply path 11 circulation purge air supply path 11b circulation purge valve 12 discharge purge air supply path 12b discharge purge valve 13 process Air supply path 13b Fuel supply air source valve 14 Midstream purge air supply path 14b Pipe purge valve 14c Check valve 15 Downstream purge air supply path 15b Backflow prevention purge valve 15c Check valve 16 Fuel dispersion air supply path 16b Fuel dispersion air control valve 16c Check valve 17 Nozzle purge air supply path 17b Spill purge valve 17c Check valve 18 High pressure air supply path 18 'Circulating high pressure purge air supply path 18b High pressure purge source valve 19 Midstream high pressure purge air supply path 19c Check valve 20 Nozzle high pressure purge air supply path 20c Check valve 21 Pressure gauge 30 Furnace 31 Dust collector 32 Pressure vessel 33 Dust remover 34 Gas turbine 34b Compressor 35 Heat exchanger 36 Steam turbine

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Seiji Roof 1 Yanagizaki-cho, Wakamatsu-ku, Kitakyushu-shi, Fukuoka Power Supply Development Co., Ltd. Power Development Co., Ltd.Wakamatsu Sogo Works (72) Inventor Yasunori Uchino 1 Power Development Co., Ltd.Wakamatsu Sogo Works (72) Inventor Hideharu Handa Hideharu Handa Yanagizaki-cho, Wakamatsu-ku, Kitakyushu-shi, Fukuoka No. 1 Power supply development Wakamatsu General Office F-term (reference) 3K064 AA11 AA12 AB01 AC05 AD03 BA24 3K068 AA11 CA24 EA03 EA07

Claims (4)

[Claims] 1. A slurry tank for storing a fuel slurry,
A slurry injection nozzle for injecting the fuel slurry into the furnace, a slurry supply path communicating with the slurry tank and the slurry injection nozzle, a slurry pump disposed in the slurry supply path, and a slurry supply path. A slurry circulation passage communicating with a slurry pump downstream and the upper part of the slurry tank, a discharge three-way valve interposed at a connection between the slurry supply passage and the slurry circulation passage, and a discharge passage downstream of the discharge three-way valve. A fuel cutoff valve disposed in the slurry supply path, a discharge purge air supply path communicating with the slurry supply path near the discharge port of the slurry pump, and supplying purge air to the slurry supply path; A discharge purge valve provided, a midstream purge air supply passage communicating with the slurry supply passage near a downstream opening of the discharge three-way valve, and the midstream purge air supply. A pipe purge valve, a water supply path communicating with the slurry supply path near an upstream opening of the fuel cutoff valve, a water wetting valve disposed in the water supply path, and a discharge three-way valve. A drainage passage communicating with the slurry supply passage near the downstream opening, and a drainage valve disposed in the drainage passage, a fuel slurry supply device, wherein when the supply of the fuel slurry is stopped, Stopping the slurry pump, closing the fuel cutoff valve, and operating the discharge three-way valve so that the slurry supply path on the upstream side of the discharge three-way valve communicates with the slurry circulation path. And purge the fuel slurry remaining in the slurry supply passage upstream of the discharge three-way valve with purge air, open the pipe purge valve, and supply the slurry between the discharge three-way valve and the fuel cutoff valve. Road with purge air Pressurize, open the fuel cutoff valve, push the fuel slurry remaining in the slurry supply passage downstream of the discharge three-way valve into the furnace, purge it, close the fuel cutoff valve, and close the pipe purge valve The water wetting valve and the drain valve are opened, water flows through the slurry supply passage between the discharge three-way valve and the fuel cutoff valve, and the water wetting valve and the drain valve are closed to discharge the water. A fuel slurry, comprising: control means for sealing water in the slurry supply passage between the three-way valve and the fuel cutoff valve, and controlling to open the pipe purge valve and the fuel cutoff valve. Feeding device. 2. A slurry tank for storing a fuel slurry,
A fuel slurry supply comprising: a slurry injection nozzle for injecting the fuel slurry into a furnace; a slurry supply path communicating with the slurry tank and the slurry injection nozzle; and a slurry pump disposed in the slurry supply path. A device,
At the start of the supply of the fuel slurry, the flow rate of the fuel slurry is larger than the initial injection amount of the fuel slurry until the front end of the flow of the fuel slurry passes through the front end of the slurry injection nozzle. Controlling the output of the slurry pump so that the flow rate is smaller than the flow rate at which the properties of the fuel slurry in the fuel slurry change, and after the front end of the flow of the fuel slurry passes through the front end portion of the slurry injection nozzle, A fuel slurry supply device, comprising: control means for performing control to reduce the output of the slurry pump until the flow rate of the slurry reaches the initial amount of the fuel slurry. 3. A slurry tank for storing a fuel slurry,
A slurry injection nozzle for injecting the fuel slurry into the furnace, a slurry supply path communicating with the slurry tank and the slurry injection nozzle, a slurry pump disposed in the slurry supply path, and a slurry supply path. A slurry circulation passage communicating with a slurry pump downstream and the upper part of the slurry tank, a discharge three-way valve interposed at a connection between the slurry supply passage and the slurry circulation passage, and a discharge passage downstream of the discharge three-way valve. A fuel slurry purging method in a fuel slurry supply device, comprising: a fuel cutoff valve disposed in a slurry supply passage, wherein when the supply of the fuel slurry is stopped, the slurry pump is stopped, and the fuel cutoff valve is stopped. And operating the discharge three-way valve so that the slurry supply path and the slurry circulation path on the upstream side of the discharge three-way valve communicate with each other, and then on the upstream side of the discharge three-way valve. Purging the fuel slurry remaining in the slurry supply path with purge air, and opening the fuel cutoff valve in a state where the slurry supply path between the discharge three-way valve and the fuel cutoff valve is pressurized with purge air. Thereby, the fuel slurry remaining in the slurry supply path on the downstream side of the discharge three-way valve is pushed into the furnace and purged, and then, from the slurry supply path on the downstream side of the discharge three-way valve to the tip of the slurry injection nozzle. A method for purging a fuel slurry, comprising washing. 4. A slurry tank for storing a fuel slurry,
A fuel slurry supply comprising: a slurry injection nozzle for injecting the fuel slurry into a furnace; a slurry supply path communicating with the slurry tank and the slurry injection nozzle; and a slurry pump disposed in the slurry supply path. A fuel slurry supply method in an apparatus, wherein at the start of the supply of the fuel slurry, the flow rate of the fuel slurry is reduced until the leading end of the flow of the fuel slurry passes through the leading end of the slurry injection nozzle. The output of the slurry pump is controlled so that the flow rate is larger than the initial input amount and smaller than the flow rate at which the property of the fuel slurry changes in the slurry injection nozzle in the slurry injection nozzle. After passing through the tip of the fuel slurry, the output of the slurry pump is reduced until the flow rate of the fuel slurry reaches the initial input amount of the fuel slurry. Fuel slurry supply wherein the to.