JPH05264001A - Method for starting pressurized fluid bed boiler - Google Patents

Abstract

PURPOSE:To prevent the gas contact parts of all the apparatus arranged from a boiler to a gas turbine from contamination with water. CONSTITUTION:A hot air AH is produced by hot blast H from an air-heating furnace 14 and is sent from a duct 26 through a duct 5 connected to a boiler 2, a cyclone dust collector 4, a duct 7, a ceramic filter 6, and a duct 9 to a gas turbine 8 in that order, whereby the gas contact parts of all the aforesaid apparatus thus arranged therebetween are heated to a prescribed temperature. When these gas contact parts reach the prescribed temperature, the air blast H is delivered the boiler 2 to fluidize and heat bed materials 3. After heating the fluid bed, the air blast H is sent from the boiler 2 through the duct 5, the cyclone dust collector 4, the dust 7, the ceramic filter 6 and the duct 9 to the gas turbine 8 in that order. During this time, although the hot blast H contains a large amount of water, since the gas contact parts of the aforesaid apparatus are preheated to the prescribed temperature by the hot air, vapor in the air blast is condensed and, therefore, dusts will not adhere to the gas contact parts.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for starting a pressurized fluidized bed boiler.

[0002]

2. Description of the Related Art FIG. 2 shows a system diagram of a system of a pressurized fluidized bed boiler used in a pressurized fluidized bed combined cycle power generation system, in which 1 is a pressure vessel and 2 is the pressure vessel 1. The boiler main body 4, which is housed inside and the bed material 3 is housed inside, is housed inside the pressure vessel 1 and is for removing dust in the exhaust gas G sent from the boiler main body 2 through the duct 5. The cyclone type dust collector, 6 is installed outside the pressure vessel 1, and a ceramic filter for removing fine dust in the exhaust gas G fed from the cyclone type dust collector 4 through the duct 7 is provided. A gas turbine for driving the electric motor / generator 10 and the compressor 11, which is driven by the exhaust gas G from which fine dust has been removed by the ceramic filter 6 and which has been fed through the duct 9, and 12 inside the boiler main body 2. Installed at the bottom of , The compressor 11 boiler discharged by compressed air A which came is fed through a duct 13 from the main body 2
Is a dispersion plate to be blown into the bed material 3, and the bed material 3 is caused to flow by the compressed air A blown from the dispersion plate 12 to form a fluidized bed.

Reference numeral 14 denotes a compressed air A introduced from the compressor 11 through a duct 13 and a duct 16 connected upstream of a valve 15 connection portion of the duct 13 by burning heavy oil or gas fuel. A hot air generating furnace for obtaining hot air H by mixing with the generated combustion gas and heating, 17 is a duct connecting the outlet side of the hot air generating furnace 14 and the downstream side of the valve 15 connection part of the duct 13, 18, 19 Is a valve installed in the middle of the ducts 16 and 17, 20 is a dust discharge pipe connected to the lower end of the boiler main body 2 for discharging ash from the boiler main body 2, and 21 is a lower end of the cyclone type dust collector 4. Dust discharge pipes connected to discharge dust from the cyclone type dust collector 4, 2
Reference numeral 2 is a dust discharge pipe connected to the lower end of the ceramic filter 6 for discharging dust from the ceramic filter 6.

When the pressurized fluidized bed boiler is started, the valve 15 is closed and the valves 18 and 19 are opened, and the motor / generator 10 is used as an electric motor to drive the compressor 11 and compressed air. A is sent from the ducts 13 and 16 to the hot air generating furnace 14 and mixed with combustion gas obtained by burning heavy oil or gas fuel to produce hot air H,
The hot air H is sent from the ducts 17 and 13 to the dispersion plate 12, and blown into the boiler body 2 from the dispersion plate 12. Therefore, the bed material 3 is fluidized by the hot air H to form a fluidized bed, and the temperature of the fluidized bed is raised. The hot air H rises in the boiler main body 2 and is then discharged to the duct 5, introduced from the duct 5 to the cyclone type dust collector 4, and after the dust is removed, discharged to the duct 7 and then from the duct 7 to the ceramic filter 6. The fine dust is removed by the ceramic filter 6 and is discharged from the duct 9 through the gas turbine 8 to the outside of the gas turbine 8.

When the fluidized bed in the boiler body 2 is heated to a predetermined temperature by the hot air H from the hot air generating furnace 14, fuel such as coal is fed into the fluidized bed from a fuel supply port (not shown). After the combustion is stabilized, the hot air generating furnace 14 is stopped, the valve 15 is opened, and the valves 18 and 19 are closed. Then, the generated combustion gas rises in the boiler main body 2 to heat the water cooling wall, and is discharged to the duct 5 as the exhaust gas G, introduced from the duct 5 to the cyclone type dust collector 4, and the cyclone type dust collector. After the dust is removed at 4, the dust is discharged to the duct 7, is introduced from the duct 7 to the ceramic filter 6, the fine dust is removed at the ceramic filter 6, and is discharged from the duct 9 to the outside of the gas turbine 8 via the gas turbine 8. To be done.

Thus, the rotation speed of the compressor 11 is gradually increased to increase the pressure of the compressed air A sent from the compressor 11 to the boiler body 2 as combustion air to increase the pressure and temperature of the exhaust gas G. Along with this, the output of the gas turbine 8 increases, and when the driving force of the electric motor becomes unnecessary as a result, the supply of electric power is stopped, and electric power generation is started using the electric motor / generator 10 as a generator. This completes the startup of the pressurized fluidized bed boiler.

[0007]

However, in the above-mentioned method for starting the pressurized fluidized bed boiler, the hot air H contains a larger amount of water than the normal air, so that the hot air H becomes a cold state at the start of starting. When contacting each device such as a certain duct 5, cyclone type dust collector 4, duct 7, ceramic filter 6, duct 9, etc., the water vapor contained in the hot air H condenses and adheres to the gas contact part of each device. In winter, the attached water flows down and a large amount of condensed water accumulates at the bottom of each device.

Further, since the fluidized bed is made to flow by the hot air H at the time of startup, the hot air H exiting the fluidized bed and passing through the duct 5, cyclone type dust collector 4, duct 7, ceramic filter 6, duct 9 and other equipment. Contains a large amount of dust. For this reason, dust adheres to the gas contact part of each device to which water adheres, and as a result, the ceramic filter 6 causes an initial rise of pressure loss and the clogging of the filter itself, and the ash and dust discharge system adheres and dries. However, there is a possibility that troubles such as solidified dust or flakes of the dust that fall off and block the dust discharge pipes 20, 21, 22 may occur.

In view of the above situation, the present invention is directed to the duct 5,
The purpose is to prevent moisture from adhering to the gas contact parts of the cyclone dust collector 4, the duct 7, the ceramic filter 6, the duct 9, and the like.

[0010]

According to the present invention, hot air, which is a mixture of combustion gas and air, is blown into a boiler body, and the bed material in the boiler body is caused to flow by the hot air to form a fluidized bed and the fluidized bed is formed. The bed is heated, hot air discharged from the boiler main body is discharged to the outside through a gas turbine, and when the fluidized bed reaches a predetermined temperature, fuel is injected into the fluidized bed and burned to generate combustion gas. Is sent from the boiler body to the gas turbine to start the gas turbine, and the compressor is driven by the gas turbine, and compressed air from the compressor is sent to the fluidized bed to start the pressurized fluidized bed boiler. In a method for starting a pressurized fluidized bed boiler, each machine disposed between the boiler body and the gas turbine by hot air containing no combustion gas before blowing the hot air into the boiler body. A gas contacting portion, water vapor in the hot air is to preheat to a temperature which does not condense.

[0011]

The gas contacting portion of each device disposed between the boiler main body and the gas turbine has steam generated by hot air containing no combustion gas before blowing hot air, which is a mixture of combustion gas and air, into the boiler main body. Is preheated to a temperature at which
Even if the hot gas is sent to each device, it is possible to prevent water from adhering to the gas contacting part of each device.

[0012]

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

FIG. 1 shows an embodiment of the present invention.
The parts denoted by the same reference numerals as those in FIG. 2 represent the same parts. Although the basic structure is substantially the same as that of the conventional one shown in FIG. 2, the feature of the present embodiment is that the duct 5 and the cyclone are provided prior to the temperature rise of the fluidized bed in the boiler body 2. The gas contacting parts of each device such as the dust collector 4, the duct 7, the ceramic filter 6 and the duct 9 are preheated with hot air containing no combustion gas, and the steam in the hot air H is condensed when the pressurized fluidized bed boiler is started. The point is that I didn't do it.

That is, an air heating device 24 is connected via a duct 23 to the hot air generating furnace 14 upstream side of the duct 16 and to the downstream side of the valve 18, and is connected to the outlet side of the air heating device 24 and halfway. The tip of a duct 26 having a valve 25 in its part is connected to the middle of the duct 5. Further, a duct 28 having a valve 27 in the middle is connected to the upstream side of the valve 19 of the duct 17, and the tip of the duct 28 is connected to the air heating device 24. The compressed air A containing no combustion gas is heated by the indirect heat exchange by the hot air H generated in 1., so that the hot air A _H having a low water content can be obtained.

When the pressurized fluidized bed boiler is started, the valve 18,
25, 27 are opened, valves 15, 18, 19 are closed, and the compressor 11 is started by the electric motor of the electric motor / generator 10.
Therefore, the compressed air A is compressed by the compressor 11 into the ducts 13, 1
6 to the hot air generator 14 and the duct 1
3, 16 and 23 are fed to the air heating device 24, and in the hot air generating furnace 14, the air is mixed with the combustion gas generated by burning heavy oil or gas fuel and heated to obtain hot air H,
The hot air H is sent from the ducts 17 and 28 to the air heating device 24.

In the air heating device 24, the compressor 11
Is heated by the hot air H from the hot air generating furnace 14 to become hot air A _H , enters the duct 5 through the duct 26, and enters from the duct 5 to the cyclone dust collector 4, the duct 7, the ceramic filter 6, and the duct 9. , The gas turbine 8 and the like, and the gas contact parts of these devices are heated to about 150 ° C. Further, the hot air H after heating the air by the air heating device 24 is discharged from the air heating device 24 to the outside, and the hot air A _H after heating each device is discharged from the gas turbine 8 to the outside. When heating each device with hot air A _H , the hot air A _H is not introduced into the boiler main body 2 because the bed material absorbs moisture especially at the start-up after a long stoppage or after a new bed material is charged. This is to prevent the retained water from being released by heating and condensing and adhering to the gas contacting portion which is still in a cold state.

When the temperature of each device from the duct 5 to the gas turbine 8 rises to a predetermined temperature, the valve 15 is closed and the valve 18 is kept open, while the valve 19 is opened and the valve 27 is opened.
Close. Therefore, the entire amount of the compressed air A from the compressor 11 is sent to the hot air generating furnace 14, and is mixed with the combustion gas obtained by burning heavy oil or gas fuel in the hot air generating furnace 14 and heated to obtain the hot air H. The obtained hot air H is sent from the hot air generating furnace 14 to the dispersion plate 12 through the ducts 17 and 13, and is blown from the dispersion plate 12 into the bed material 3 housed in the boiler body 2. Therefore, the bed material 3 is fluidized to form a fluidized bed, and the fluidized bed is heated and heated.

The bed material 3 is fluidized to form a fluidized bed.
Hot air H after heating and heating the fluidized bed
The inside of the ira body 2 is raised and introduced into the duct 5,
From cyclone type dust collector 4, duct 7, ceramic filter
Through each device such as the filter 6, the duct 9, the gas turbine 8,
It is discharged to the outside of the gas turbine 8. At this time, a large amount of hot air H
It contains a certain amount of water vapor, but duct 5, cyclone type
Dust collector 4, duct 7, ceramic filter 6, duct
9, each equipment such as gas turbine 8 is already hot air A _HBy
Since it is preheated to a temperature at which steam does not condense
The water vapor contained in the wind H does not condense
Duct 5, cyclone type dust collector 4, duct 7, ceramic
Each equipment such as an exhaust filter 6, a duct 9 and a gas turbine 8
Moisture does not adhere to the gas contact part of. In addition to hot air H
Is accompanied by dust as the bed material 3 is fluidized.
However, there was no water on the gas contact parts of the above equipment.
Therefore, dust may not adhere to the gas contact part of each device.
Yes.

When the fluidized bed in the boiler body 2 reaches a predetermined temperature, a fuel such as coal is injected into the fluidized bed from a fuel supply port (not shown) and burned to generate combustion gas, which stabilizes combustion. After that, the hot air generating furnace 14 is stopped, the valve 15 is opened, and the valves 18 and 19 are closed. The combustion gas thus generated heats the water cooling wall while rising in the boiler main body 2, is discharged to the duct 5 as exhaust gas, is introduced from the duct 5 to the cyclone type dust collector 4, and is discharged to the cyclone type dust collector 4
After the dust is removed by the
Is introduced into the ceramic filter 6 from which the fine dust is removed by the ceramic filter 6 and discharged from the duct 9 to the outside of the gas turbine 8 via the gas turbine 8. The rotational speed of the compressor 11 is gradually increased to increase the pressure of the compressed air A sent from the compressor 11 to the boiler body 2 as combustion air, and the pressure and temperature of the exhaust gas G are increased to increase the temperature of the gas turbine 8. When the output increases and as a result, the driving force of the electric motor becomes unnecessary, the supply of electric power is stopped and the generator of the electric motor / generator 10 is driven to start power generation. This completes the startup of the pressurized fluidized bed boiler.

In the embodiment of the present invention, the case where the hot air for preheating the gas contact portion is obtained by indirectly exchanging the compressed air with the combustion gas for heating the fluidized bed has been described.
You may provide a dedicated hot air generation furnace, etc.,
It goes without saying that various changes can be made without departing from the scope of the present invention.

[0021]

As described above, according to the method for starting the pressurized fluidized bed boiler of the present invention, moisture does not adhere to the gas contacting parts of each equipment from the boiler body to the gas turbine at the time of starting. Therefore, the excellent effect that dust does not adhere to the gas contacting portion can be obtained.

[Brief description of drawings]

FIG. 1 is a system diagram of an embodiment of a method for starting a pressurized fluidized bed boiler according to the present invention.

FIG. 2 is a system diagram of an embodiment of a conventional method for starting a pressurized fluidized bed boiler.

[Explanation of symbols]

2 Boiler body 3 Bed material 4 Cyclone dust collector (equipment) 5 Duct (equipment) 6 Ceramic filter (equipment) 7 Duct (equipment) 8 Gas turbine (equipment) 11 Compressor H Hot air A _H Heat / air

Claims (1)

[Claims] 1. A hot air mixed with combustion gas and air is blown into a boiler main body, the bed material in the boiler main body is caused to flow by the hot air to form a fluidized bed, and the fluidized bed is heated. The discharged hot air is discharged to the outside through a gas turbine, and when the fluidized bed reaches a predetermined temperature, fuel is injected into the fluidized bed and burned to generate combustion gas,
The combustion gas is sent from the boiler body to the gas turbine to start the gas turbine, the compressor is driven by the gas turbine, and compressed air from the compressor is sent to the fluidized bed to start the pressurized fluidized bed boiler. In the method for starting a pressurized fluidized bed boiler as described above, before the hot air is blown into the boiler main body, contact of each device arranged between the boiler main body and the gas turbine with hot air containing no combustion gas is performed. A method for starting a pressurized fluidized bed boiler, comprising preheating the gas part to a temperature at which the steam in the hot air does not condense.