JPH06257717A - Method and device for controlling height of fluidized bed/of pressurized fluidized bed type boiler - Google Patents

Abstract

PURPOSE:To provide a pressurized fluidized bed type boiler in which a trouble caused when BM (bed material) is fed into a furnace. CONSTITUTION:An inner side of a BM tank 15 is pressurized with a BM tank pressurized air adjusting valve 7 in response to a difference between a fluidized bed height set value of a furnace 10 and an actual fluidized bed height, thereby a pressure difference between the BM tank 15 and the furnace 10 is adjusted, a force for pushing the material from the BM tank 15 to the furnace 10 is increased to improve a flow of BM from the BM tank 15 to the furnace 10.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pressurized fluidized bed boiler, and more particularly to control of the fluidized bed height of a pressurized fluidized bed boiler which performs load adjustment by increasing or decreasing the fluidized bed height.

[0002]

2. Description of the Related Art FIG. 3 is a block diagram of a conventional pressurized fluidized bed boiler.
Shown in. Furnace 10 housed in a pressure vessel (not shown)
The bed material (hereinafter sometimes referred to as BM), which is a fluid medium, is kept in a fluid state by compressed air,
The fluidized bed 11 is formed. Combustion of the fuel in the fluidized bed 11 heats the feed water in the heat transfer tubes 12 arranged in the furnace 10 to generate steam. Further, the exhaust gas generated in the furnace 10 is introduced into a gas turbine (not shown) or the like through the exhaust gas pipe 13. In addition to the furnace 2, a BM tank 15 is also stored in the pressure vessel, and the furnace 10 and the BM are
With respect to the tank 15, the BM supply line 14 and the BM extraction line 16 supply and extract the BM into the furnace 10, respectively. When the load is increased, the bed height of the fluidized bed 11 is increased, and when the load is decreased, the bed height of the fluidized bed 11 is lowered.

When the bed height of the fluidized bed 11 is increased, the BM is charged into the furnace 10 as follows. That is, the furnace 1
The BM tank pressure equalizing valve 17 provided in the pipe 18 connecting the empty column section of 0 and the empty column section of the BM tank 15 is fully closed, and the BM tank 15 is pressurized by the pressurized air supplied from the pressurized air control valve 7 to the BM. The inside of the BM tank 15 is pressurized so that the pressure difference between the tank 15 and the furnace 10 becomes a constant value, and the BM generated by this pressure is generated.
The force of pushing the BM into the furnace 10 by the pressure difference between the tank 15 and the furnace 10, and the L valve air flow rate control valve 2 provided in the L valve 20 connected to the vertical pipe 19 at the outlet of the BM tank 15.
The BM in the BM tank 15 is pushed into the furnace 10 by both the force of pushing the BM into the furnace 10 with the air from 1.
A furnace-BM tank differential pressure transmitter 22 is provided between the empty tower section of the furnace 10 and the empty tower section of the BM tank 15.
The pressure difference between 0 and the BM tank 15 can be measured.

The set value of the differential pressure between the furnace 10 and the BM tank 15 is as follows: the pipe diameter of the BM supply line 14, the BM particle size, and the air from the L valve air flow rate control valve 21 to the furnace 10.
Force to push M and B by BM tank 15 and furnace 10
The design pressure difference is calculated from the balance of the force that pushes in M. If the pressure difference between the BM tank 15 and the furnace 10 exceeds the set value, the BM flows too much, and if it falls below the set value, the flow of the BM changes. It gets worse.

The conventional method of controlling the differential pressure between the BM tank 15 and the furnace 10 is as shown in FIG. 4, and the differential pressure detection signal 25 of the furnace-BM tank differential pressure from the furnace-BM tank differential pressure transmitter 22 and the furnace-BM are shown. The deviation from the tank differential pressure setting signal 1 is calculated by the subtractor 6, and the furnace-BM tank differential pressure deviation signal 26 is obtained via the PI controller 2 and the automatic / manual switch 27. This furnace-
The opening degree of the BM tank pressurized air control valve 7 is adjusted by the BM tank differential pressure deviation signal 26. However, since the particle size of BM is not constant and changes over time, B
BM tank 1 of BM supply line 14 due to change in M particle size
5 Blockage of the vertical pipe 19 connected to the outlet, BM
Backflow of BM to the vertical pipe 19 of the BM supply line 14 due to insufficient differential pressure between the tank 15 and the air injection portion of the L valve air flow rate control valve 21, or the flow of BM due to a trouble of the L valve air flow rate control valve 21. No consideration was given to the difficulty of supplying BM to the furnace 10 due to the shortage of air for transportation.

[0006]

In the above-mentioned conventional technique, the vertical pipe 19 of the BM supply line 14 is clogged and the differential pressure between the BM tank 15 and the air injection portion of the L valve air flow rate control valve 21 is insufficient. BM to BM tank 15 by BM from BM supply line 14 to vertical pipe 19
No consideration has been given to the fact that it becomes difficult to supply BM to the furnace 10 due to various causes such as an increase in the temperature of the L valve, a trouble of the L valve air flow rate control valve 21, and a shortage of air for carrying the air flow of the BM. In this case, BM may not be supplied to the furnace 10 and the bed height of the fluidized bed 11 may not be increased. An object of the present invention is to provide a pressurized fluidized bed boiler that eliminates the trouble at the time of charging BM (bed material) into a furnace.

[0007]

The above object of the present invention can be achieved by the following constitutions. That is, by adjusting the differential pressure between the furnace and the fluidized medium tank and adjusting the amount of pressurized air for transportation, the fluidized medium is extracted into the fluidized medium tank and returned to the fluidized medium tank, and the height of the fluidized bed of the furnace is increased. In a pressurized fluidized bed boiler in which the load is changed and controlled, when the load increase is requested, the amount of pressurized air in the fluidized medium tank is increased in accordance with the deviation between the fluidized bed height in the furnace and its set value. The fluidized bed height control method of the pressurized fluidized bed boiler that adjusts the fluidized medium height within the set range, or the flow to the fluidized medium tank by adjusting the differential pressure between the furnace and the fluidized medium tank and the amount of pressurized air for transportation In a pressurized fluidized bed boiler that extracts the medium and returns the fluidized medium from the fluidized medium tank, and controls the load by changing the height of the fluidized bed of the furnace,
A fluid medium tank that adjusts the fluid medium height in the furnace within a set range according to the deviation between the fluid bed height detector in the furnace and the detection signal of the fluid bed height detector in the furnace and its set value signal. Is a fluidized bed height control device for a pressurized fluidized bed boiler, comprising:

[0008]

When a problem occurs in the BM supply line that supplies BM from the BM tank to the furnace when a load increase of the pressurized fluidized bed boiler is requested (when the vertical portion of the BM supply line is clogged, the vertical direction of the BM supply line B due to air from the air input part due to insufficient differential pressure between the air input part of the L-shaped valve part consisting of the partial pipe and the horizontal part pipe and the BM tank
When the M is pushed up to the BM tank, when the air for carrying the air flow of the BM is insufficient due to a trouble of the air injection part of the L-shaped valve part), the BM is not injected into the furnace and Since the fluidized bed height is less likely to rise, a deviation occurs between the measured value and the set value of the fluidized bed height. By adjusting the pressure difference between the BM tank and the furnace by increasing the amount of pressurization of the BM tank according to the magnitude of the bed height deviation, the force for pushing the BM into the furnace from the BM tank increases and the BM tank moves into the furnace. BM flow is improved.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to the drawings. The configuration of the BM supply / extraction system of the pressurized fluidized bed boiler of this embodiment is shown in FIG. 2, and the fluidized bed high transmitter 30 is added to the pressurized fluidized bed boiler of the conventional technique described in FIG. It is a thing. The control method of the differential pressure between the BM tank 15 and the furnace 10 of this embodiment is as shown in FIG. 1, and the difference from the conventional technology shown in FIG. 4 is the fluidized bed height in the furnace 10 by the fluidized bed height transmitter 30. This is the addition of a control method based on detection signals. Explaining the differential pressure control method shown in FIG. 1, the furnace-B
Based on the furnace-BM tank differential pressure deviation signal 26 of the furnace-BM tank differential pressure detection signal 25 and the furnace-BM tank differential pressure setting signal 1 from the M tank differential pressure transmitter 22, the subtractor 6, PI control The furnace-BM tank differential pressure correction signal 8 is added through the adder 3 and corrected. This furnace-
The BM tank differential pressure correction signal 8 is obtained by calculating the deviation between the fluidized bed height detection signal 31 from the fluidized bed height transmitter 30 and the fluidized bed height setting signal 9 by the subtractor 6, and the obtained fluidized bed height deviation signal 32. Is set by the function transmitter 5 according to
The opening degree of the M tank pressurized air control valve 7 is adjusted. The opening degree of the BM tank pressurized air control valve 7 is controlled by the automatic / manual switch 27.
You can switch to automatic or manual with.

Thus, when the BM is not charged into the furnace 10 and the height of the fluidized bed in the furnace 10 becomes difficult to rise, a deviation occurs between the measured value and the set value of the fluidized bed height. Since the opening degree of the BM tank pressurized air control valve 7 is adjusted according to the size of the BM tank 15, the force for pushing the BM tank 15 and pushing the BM from the BM tank 15 into the furnace 10 is increased, and the flow of the BM is improved. Become. Therefore, even if the vertical pipe 19 of the BM supply line 14 is clogged,
The L valve air flow rate control valve 21 due to the lack of the differential pressure between the tank 15 and the air injection section near the L valve air flow rate control valve 21
Even if the BM is pushed up to the BM tank 15 by the air from the BM, or if the air flow carrier air of the BM is insufficient due to a trouble of the L valve air flow rate control valve 21,
The pressure difference between the tank 15 and the furnace 10 is adjusted appropriately.

[0011]

As described in detail above, according to the present invention, troubles at the time of supplying BM to a furnace due to clogging of the BM supply line at the time of increasing the load can be eliminated, and the flow of BM in the BM supply line can be eliminated. You can get better.

[Brief description of drawings]

FIG. 1 is a diagram showing a furnace-BM tank differential pressure control system according to an embodiment of the present invention.

FIG. 2 is a BM of a pressurized fluidized bed boiler according to an embodiment of the present invention.
Configuration diagram of supply and extraction system.

FIG. 3 is a configuration diagram of a BM supply / extraction system of a conventional pressurized fluidized bed boiler.

FIG. 4 is a diagram showing a conventional furnace-BM tank differential pressure control system.

[Explanation of symbols]

1 ... Furnace-BM tank differential pressure setting signal, 7 ... BM tank pressurized air control valve, 8 ... Furnace-BM tank differential pressure correction signal, 9
... fluidized bed height setting signal, 10 ... furnace, 11 ... fluidized bed, 14
... BM supply line, 15 ... BM tank, 16 ... BM extraction line, 19 ... Vertical pipe, 20 ... L valve, 21
... L valve air flow control valve, 22 ... Furnace-BM tank differential pressure transmitter, 25 ... Furnace-BM tank differential pressure detection signal, 26
... Furnace-BM tank differential pressure deviation signal, 27 ... Automatic / manual switcher, 30 ... Fluidized bed level transmitter, 31 ... Fluidized bed height detection signal, 32 ... Fluidized bed height deviation signal

Claims (2)

[Claims] 1. A fluid medium is withdrawn from the fluid medium tank and returned from the fluid medium tank by adjusting the differential pressure between the furnace and the fluid medium tank and the amount of pressurized air for transportation, and the fluid bed of the furnace is In a pressurized fluidized bed boiler in which the load is controlled by changing the height, when the load increase is requested, the amount of pressurized air in the fluidized medium tank is increased according to the deviation between the fluidized bed height in the furnace and its set value. A method for controlling a fluidized bed height of a pressurized fluidized bed boiler, which comprises adjusting a height of a fluidized medium in a furnace within a set range. 2. A fluidized medium is withdrawn from the fluidized medium tank and returned from the fluidized medium tank by adjusting the differential pressure between the furnace and the fluidized medium tank and the amount of pressurized air for transportation, and the fluidized bed of the furnace is In a pressurized fluidized bed boiler in which the load is controlled by changing the height, the furnace is selected according to the difference between the fluidized bed height detector in the furnace and the detection signal of the fluidized bed height detector in the furnace and its set value signal. A fluidized bed height control device for a pressurized fluidized bed boiler, comprising: a pressurized air amount adjusting means of a fluidized medium tank for adjusting the height of the fluidized medium within the set range.