JPH04297701A - Steam temperature controller for pressurized fluidized bed boiler - Google Patents

Abstract

PURPOSE:To provide a pressurized fluidized bed boiler having generated electric energy having high follow-up properties to an output command. CONSTITUTION:A feed water command 48 obtained by converting an output command 39 by a function generator 47 is transmitted directly over a feed valve 24. The layer height 34 of a bed material in a fluidized bed boiler body is adjusted in place of the transmission of a feed water command 48, thus controlling the steam temperature 38 of the inlet of a steam turbine.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a steam temperature control device for a pressurized fluidized bed boiler.

0002

BACKGROUND OF THE INVENTION Currently, pressurized fluidized bed boilers are being developed which have high thermal efficiency and are less likely to generate environmental pollutants.

[0003] In short, the pressurized fluidized bed boiler is a fluidized bed boiler housed inside a pressure vessel and operated under pressurized conditions, and generates electricity by guiding the generated steam to a steam turbine. In addition, the generated exhaust gas can be used to turn a gas turbine to generate electricity or drive a compressor, so it is expected that high thermal efficiency will be achieved.

[0004] Furthermore, since combustion occurs at a low temperature and the residence time of the exhaust gas is long, it is expected that the amount of nitrogen oxides generated will be reduced by supplying a desulfurizing agent together with the fuel.

Furthermore, since high thermal efficiency can be obtained, it is expected that the device can be made smaller.

[0006] Hereinafter, an outline of a steam temperature control device for a pressurized fluidized bed boiler, which is currently being studied, will be explained using FIGS. 4 and 5.

In FIG. 4, 1 is a pressure vessel, 2 is a fluidized bed boiler body housed inside the pressure vessel 1, and 3 is a bed of silica sand or the like inserted inside the fluidized bed boiler body 2 for forming a fluidized bed. 4 is a bed material storage tank 5 provided outside the fluidized bed boiler body 2 for storing the bed material 3;
7 is a bed material supply path provided between the fluidized bed boiler main body 2 and the bed material storage tank 4; 6 is a bed material discharge path provided between the fluidized bed boiler main body 2 and the bed material storage tank 4; 8 is a bed material supply valve that is connected to the bed material supply path 5 and supplies the bed material 3 from the bed material storage tank 4 to the fluidized bed boiler main body 2 using the air pressure inside the pressure vessel 1; 8 is a bed material storage tank; 4 and releases the pressure inside the bed material storage tank 4 to the atmosphere, thereby transferring the bed material 3 from the fluidized bed boiler main body 2 to the bed material storage tank 4.
This is a bed material discharge valve for discharging to.

Further, reference numeral 9 denotes a fuel supply path for supplying a fuel 10 such as slurry-like pulverized coal containing a desulfurizing agent to the fluidized bed boiler main body 2, 11 a fuel pump provided in the middle of the fuel supply path 9, and 12 is a fuel valve provided on the outlet side of the fuel pump 11.

Reference numeral 13 denotes an exhaust gas passage for discharging the exhaust gas 14 generated in the fluidized bed boiler main body 2 and removed by a dust removing device (not shown); 15 is a gas turbine provided in the middle of the exhaust gas passage 13; and 16 17 is a generator connected to the gas turbine 15; 18 is an air supply path that supplies air 19 to the fluidized bed boiler main body 2; and 20 is an air supply path. This is a compressor installed in the middle of the passage 18 and connected to the gas turbine 15.

Furthermore, 21 is a water supply channel for supplying boiler water 22 to the fluidized bed boiler main body 2, 23 is a water supply pump provided in the middle of the water supply channel 21, and 24 is provided on the outlet side of the water supply pump 23. A water supply valve, 25 is a furnace path connected to the water supply flow path 21 and constitutes the fluidized bed boiler body 2, 26 is a superheater connected to the outlet side of the furnace path 25, and 27 is an inlet side of the furnace path 25 of the water supply flow path 21. 28 is a spray flow rate adjustment valve provided in the middle of the spray channel 27, and 29 is a spray channel for spraying the boiler water 22 to the inlet side of the superheater 26. 31 is a turbine control valve provided in the middle of the steam flow path 29; and 32 is a generator connected to the steam turbine 30.

33 is a level meter for measuring the layer height 34 of the bed material 3 inside the fluidized bed boiler main body 2; 35 is a furnace pass outlet temperature sensor for detecting the furnace pass outlet temperature 36;
37 is a turbine inlet temperature sensor that detects the steam turbine inlet temperature 38.

In FIG. 5, 39 is an output command from the outside, 40 is a function generator that converts the output command 39 into a layer height command 41, and 4
2 is a subtracter that subtracts the bed height command 41 and the actual bed height 34 detected by the level meter 33 to obtain the bed height deviation 43; 44 is a bed material supply valve 7 or bed material based on the bed height deviation 43; This is a high-low monitor that sends open/close commands 45, 46 to one side of the discharge valve 8.

47 is a function generator that converts the output command 39 into a water supply command 48; 49 is the actual furnace pass outlet temperature 36 detected by the furnace pass outlet temperature sensor 35 and the furnace pass outlet set temperature set in the setting device 50; 51, a subtractor for calculating the furnace pass outlet temperature deviation 52; 53, a controller that uses the furnace pass outlet temperature deviation 52 as the water supply control signal 54; 55;
is an adder that adds the water supply command 48 and the water supply control signal 54 to obtain a corrected water supply command 56 to be sent to the water supply valve 24.

A subtractor 57 calculates a steam turbine inlet temperature deviation 60 by subtracting the actual steam turbine inlet temperature 38 detected by the turbine inlet temperature sensor 37 and the steam turbine inlet set temperature 59 set in the setting device 58; Reference numeral 61 is a controller that sends the steam turbine inlet temperature deviation 60 to the spray flow rate regulating valve 28 as a spray flow rate command 62.

To operate the pressurized fluidized bed boiler, first, the air 19 compressed by the compressor 20 is supplied to the inside of the pressure vessel 1 to increase the pressure inside the pressure vessel 1, and the air 19 is pumped to the bottom of the pressure vessel 1. The bed material 3 inside the fluidized bed boiler main body 2 is fluidized by supplying it to the fluidized bed boiler main body 2 from the fluidized bed boiler main body 2.

Next, the fuel pump 11 is driven to supply fuel 10 such as slurry-like pulverized coal containing a desulfurizing agent from the fuel supply path 9 to the fluidized bed boiler main body 2.
The fuel 10 is combusted by the air 19 supplied inside.

The exhaust gas 14 generated inside the fluidized bed boiler main body 2 is removed from dust by a dust removal device (not shown) and then discharged from the exhaust gas passage 13. On the way, the exhaust gas 14 is led to the gas turbine 15 and rotates the gas turbine 15. The generator 17 is driven to generate electricity, and the compressor 20 is driven to generate air 1.
It is used to compress 9.

On the other hand, boiler water 22 is supplied from a water supply passage 21 by a water supply pump 23 to the inside of the fluidized bed boiler main body 2 whose temperature has been increased by the combustion of the fuel 10, and the boiler water 22 is supplied from a water supply passage 21 to the inside of the fluidized bed boiler main body 2 whose temperature has been increased by the combustion of the fuel 10. 25, the boiler water 22 is heated and evaporated.

Water is separated from the evaporated boiler water 22 in a steam/water separator (not shown), and only the steam is led to a superheater 26 where it is further superheated and turned into high-temperature steam.

At this time, the boiler water 2 flowing through the water supply channel 21
The temperature of the steam introduced into the superheater 26 is adjusted by spraying a portion of the steam into the superheater 26 through the spray channel 27.

The high-temperature steam superheated by the superheater 26 is led to the steam turbine 30 through the steam flow path 29, rotates the steam turbine 30, and drives the generator 32 to generate electricity.

By opening the bed material supply valve 7 connected to the bed material supply path 5, the bed material 3 is transferred from the bed material storage tank 4 to the inside of the fluidized bed boiler main body 2 by the air pressure inside the pressure vessel 1. Supplied and bed material storage tank 4
By opening the bed material discharge valve 8 connected to the bed material storage tank 4 and releasing the pressure inside the bed material storage tank 4 to the atmosphere, the bed material 3 is discharged from the fluidized bed boiler main body 2 to the bed material storage tank 4.
It is designed to be discharged to

The pressurized fluidized bed boiler is controlled as follows.

That is, regarding the amount of water supplied to the boiler water 22,
The function generator 47 converts the output command 39 from the outside into a water supply command 4.
At the same time, the actual furnace pass outlet temperature 36 detected by the furnace pass outlet temperature sensor 35 and the furnace pass outlet set temperature 51 set in the setting device 50 are subtracted by the subtractor 49 to obtain the furnace pass outlet temperature deviation. 52 is determined, the furnace pass outlet temperature deviation 52 is set as the water supply control signal 54 by the controller 53, and the adder 55 adds the water supply command 48 and the water supply control signal 54 to obtain the corrected water supply command 56. Accordingly, the opening degree of the water supply valve 24 is controlled so that the furnace pass outlet temperature 36 becomes a constant value equal to the furnace pass outlet set temperature 51.

Regarding the spray amount to the inlet of the superheater 26, the actual steam turbine inlet temperature 38 detected by the turbine inlet temperature sensor 37 and the steam turbine inlet set temperature 59 set in the setting device 58 are subtracted by the subtractor 57. The steam turbine inlet temperature deviation 60 is determined by the controller 61 as the spray flow rate command 62, and based on the spray flow rate command 62, the steam turbine inlet temperature 38 is set to the steam turbine inlet set temperature 59. The opening degree of the spray flow rate adjustment valve 28 is controlled so that the spray flow rate adjustment valve 28 has an equal constant value.

The reason why the water supply amount is controlled so that the furnace pass outlet temperature 36 is a constant value is because the ability to adjust the steam turbine inlet temperature 38 by spraying is low. By keeping the furnace pass outlet temperature 36 at the outlet 25 at a constant value by controlling the amount of water supplied, the steam turbine inlet temperature 38 is roughly adjusted by the amount of water supplied, and the spray is adjusted to the temperature 38 at the steam turbine inlet.
This is for fine adjustment of 8.

Regarding the bed height of the bed material 3 inside the fluidized bed boiler main body 2, the output command 39 is converted into a bed height command 41 by a function generator 40, and the bed height command 41 and the actual bed height detected by the level meter 33 are converted into a bed height command 41. The height 34 is subtracted by the subtractor 42 to obtain the layer height deviation 4.
3 and high/low monitor 4 based on the layer height deviation 43.
4 to find the opening/closing command 45 or 46, and the opening/closing command 45 or 4
6, either the bed material supply valve 7 or the bed material discharge valve 8 is opened or closed so that the bed height 34 of the bed material 3 inside the fluidized bed boiler main body 2 is at a level corresponding to the output command 39.

[0028]

[Problems to be Solved by the Invention] However, the steam temperature control device for the pressurized fluidized bed boiler has the following problems.

That is, when the output command 39 changes, in order to secure the amount of power generated according to the output command 39, it is necessary to change the amount of steam generated and also the amount of water supply. Since the outlet temperature 36 is used for control to keep it constant, the control over the furnace path outlet temperature 36 is hindered, and the water supply amount cannot follow the change in the output command 39 (the control shown in FIG. 5). According to the circuit,
When the output command 39 changes, the subtractor 49 and controller 53
(The system functions to keep the furnace pass outlet temperature 36 constant and prevents the water supply amount from changing even if the output command 39 changes), so the follow-up of the amount of power generation to the output command 39 is poor. Become.

In view of the above-mentioned circumstances, the present invention provides an output command 3
It is an object of the present invention to provide a steam temperature control device for a pressurized fluidized bed boiler that is capable of improving followability of the amount of power generation relative to No. 9.

[0031]

[Means for Solving the Problems] The present invention provides a fluidized bed boiler main body 2 housed in a pressure vessel 1, and a fluidized bed boiler main body 2 housed in a pressure vessel 1.
A bed material supply valve 7 and a bed material discharge valve 8 for supplying and discharging bed material 3 from a bed material storage tank 4 attached to the fluidized bed boiler main body 2 to the fluidized bed boiler main body 2.
A superheater connected to the outlet side of the furnace path 25, which is equipped with a level meter 33 that detects the bed height 34 of the bed material 3 inside, and a water supply valve 24 that supplies boiler water 22 to the furnace path 25 of the fluidized bed boiler body 2. A turbine inlet temperature sensor 37 is provided between the steam turbine 26 and the external steam turbine 30 to detect the steam turbine inlet temperature 38.
and a function generator 47 for determining a water supply command 48 to be sent directly to the water supply valve 24 from the turbine inlet temperature sensor 37.
The actual steam turbine inlet temperature 38 detected by the setting device 5
A subtractor 57 that obtains a steam turbine inlet temperature deviation 60 by subtracting the steam turbine inlet temperature deviation 60 from the steam turbine inlet set temperature 59 set to 8.
, the steam turbine inlet temperature deviation 60 is determined by the layer height control signal 63.
a controller 64 that converts the output command 39 into a bed height command 41, an adder 66 that adds the bed height command 41 and the bed height control signal 63 to obtain a corrected bed height command 65.
A subtractor 42 subtracts the corrected layer height command 65 from the actual layer height 34 detected by the level meter 33 to obtain the layer height deviation 43.
and an opening/closing command 45 or 4 to open or close one of the bed material supply valve 7 or the bed material discharge valve 8 based on the bed height deviation 43.
This invention relates to a steam temperature control device for a pressurized fluidized bed boiler, characterized in that it is equipped with a high/low monitor 44 for determining the temperature of 6.

[0032]

[Action] The action of the present invention is as follows.

Regarding the amount of water supplied to the boiler water 22, the output command 39 from the outside is converted into a water supply command 48 by a function generator 47, and the water supply command 48 is sent directly to the water supply valve 24, so that the amount of water supplied to the boiler water 22 is determined according to the output command 39. to control the opening degree of the water supply valve 24.

[0034] Thereby, the amount of water supply and thus the amount of steam can be immediately changed in response to a change in the water supply command 48, so that the amount of power generation can follow the output command 39 well.

The steam temperature on the inlet side of the steam turbine 30 is controlled by the height of the bed material 3 inside the fluidized bed boiler main body 2. That is, the output command 39 is converted into a layer height command 41 by the function generator 40, and the actual steam turbine inlet temperature 38 detected by the turbine inlet temperature sensor 37 and the setting device 58 are
A steam turbine inlet temperature deviation 60 is obtained by subtracting the steam turbine inlet set temperature 59 set at a subtracter 57,
The steam turbine inlet temperature deviation 60 is set as a bed height control signal 63 by the controller 64, and the bed height command 41 and the bed height control signal 63 are added by an adder 66 to obtain a corrected bed height command 65, which is sent to the subtractor 4.
2, the corrected layer height command 65 and the actual layer height 34 detected by the level meter 33 are subtracted by the subtractor 42 to obtain the layer height deviation 43.
is determined, and the high-low monitor 44 is calculated based on the layer height deviation 43.
Find the opening/closing command 45 or 46 with
Based on this, the bed height 34 of the bed material 3 inside the fluidized bed boiler main body 2 is set to a level corresponding to the output command 39 by the bed height control signal 63.
Either the bed material supply valve 7 or the bed material discharge valve 8 is opened or closed so that the corrected level is achieved.

[0036]

Embodiments Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIGS. 1 to 3 show one embodiment of the present invention.

In addition, in the figure, the basic configuration and details of each component of the steam temperature control device for a pressurized fluidized bed boiler are shown in FIG.
Since the same components as those shown in FIG. 5 are included, the same components will be given the same reference numerals and the explanation will be omitted.Hereinafter, only the configuration unique to the present invention will be explained. .

Water supply command 48 generated by function generator 47
is sent directly to the water supply valve 24.

Further, a controller 64 is provided which uses the steam turbine inlet temperature deviation 60 as a layer height control signal 63, and the function generator 40
An adder 6 adds the floor height command 41 generated in and the floor height control signal 63 to obtain a corrected floor height command 65 and sends it to the subtracter 42.
6 will be provided.

Next, the operation will be explained.

The process of operating the pressurized fluidized bed boiler is the same as that shown in FIG. 4, so the explanation will be omitted.

In the present invention, the pressurized fluidized bed boiler is controlled as follows.

That is, regarding the amount of water supplied to the boiler water 22,
The function generator 47 converts the output command 39 from the outside into a water supply command 4.
8 and sends the water supply command 48 directly to the water supply valve 24, thereby controlling the opening degree of the water supply valve 24 according to the output command 39.

[0045] As a result, the amount of water supply and thus the amount of steam can be immediately changed in response to a change in the water supply command 48, so that the amount of power generation can follow the output command 39 well.

The steam temperature on the inlet side of the steam turbine 30 is controlled by the bed height of the bed material 3 inside the fluidized bed boiler main body 2. That is, the output command 39 is converted into a layer height command 41 by the function generator 40, and the actual steam turbine inlet temperature 38 detected by the turbine inlet temperature sensor 37 and the setting device 58 are
A steam turbine inlet temperature deviation 60 is obtained by subtracting the steam turbine inlet set temperature 59 set to by a subtractor 57,
The steam turbine inlet temperature deviation 60 is set as the bed height control signal 63 by the controller 64, and the bed height command 41 and the bed height control signal 63 are added by the adder 66 to obtain the corrected bed height command 65, which is sent to the subtracter 4.
2, the corrected layer height command 65 and the actual layer height 34 detected by the level meter 33 are subtracted by the subtractor 42 to obtain the layer height deviation 43.
is determined, and the high-low monitor 44 is calculated based on the layer height deviation 43.
Find the opening/closing command 45 or 46 with
Based on this, the bed height 34 of the bed material 3 inside the fluidized bed boiler main body 2 is set to a level corresponding to the output command 39 by the bed height control signal 63.
Either the bed material supply valve 7 or the bed material discharge valve 8 is opened or closed so that the corrected level is achieved.

FIG. 3 is a graph showing the relationship between the steam turbine inlet temperature and the layer height. According to the graph, it can be seen that there is a proportional relationship between the two, so that the steam turbine inlet temperature 3
8, the bed height 34 of the bed material 3 inside the fluidized bed boiler main body 2 is increased, and conversely, when the steam turbine inlet temperature 38 is desired to be lowered, the bed height 34 of the bed material 3 inside the fluidized bed boiler main body 2 is increased. It can be seen that by lowering the temperature, the steam turbine inlet temperature 38 can be controlled.

Incidentally, the combustion temperature inside the boiler main body 2 is controlled to be constant by a control device (not shown). Furthermore, the amount of spray to the inlet of the superheater 26 is controlled in the same manner as shown in FIG. The need for the controller 61 is reduced, and the controller 61 can be replaced with a proportional controller instead of a general proportional-integral controller, making it possible to use an auxiliary configuration that sprays only a certain amount when a temperature deviation occurs. .

It should be noted that the present invention is not limited to the above-described embodiments, and it goes without saying that various changes can be made without departing from the gist of the present invention.

[0050]

[Effects of the Invention] As explained above, according to the present invention,
In a pressurized fluidized bed boiler, an excellent effect can be achieved in that the followability of the amount of power generation to the output command can be improved.

[Brief explanation of drawings]

FIG. 1 is a schematic overall view of a pressurized fluidized bed boiler in one embodiment of the present invention.

FIG. 2 is a control circuit diagram of a steam temperature control device for the pressurized fluidized bed boiler in FIG. 1;

FIG. 3 is a graph showing the relationship between steam turbine inlet temperature and layer height.

FIG. 4 is a schematic overall view of a pressurized fluidized bed boiler currently under consideration.

FIG. 5 is a control circuit diagram of the steam temperature control device of the pressurized fluidized bed boiler in FIG. 4;

[Explanation of symbols]

1 Pressure vessel 2 Fluidized bed boiler main body 3
Bed material 4 Bed material storage tank 7
Bed material supply valve 8
Bed material discharge valve 22 Boiler water 24 Water supply valve 25 Furnace path 26 Superheater 30 Steam turbine 33 Level meter 34 Bed height 37 Turbine inlet temperature sensor 38
Steam turbine inlet temperature 39
Output command 40 Function generator 41 Layer height command 42 Subtractor 43 Layer height deviation 44 Hi-low monitor 45, 46
Function generator 48 Water supply command 57 Subtractor 58 Setter 59 Steam turbine inlet set temperature 60
Steam turbine inlet temperature deviation 63
Layer height control signal 64 Controller 65 Correction layer height command 66 Adder

Claims (1)

[Claims] 1. A fluidized bed boiler main body 2 housed in a pressure vessel 1 and a bed material 3 from a bed material storage tank 4 attached to the fluidized bed boiler main body 2 to the fluidized bed boiler main body 2.
a bed material supply valve 7 and a bed material discharge valve 8 for supplying and discharging bed material, a level meter 33 for detecting the bed height 34 of the bed material 3 inside the fluidized bed boiler main body 2, and a furnace of the fluidized bed boiler main body 2. A turbine that is equipped with a water supply valve 24 that supplies boiler water 22 to a path 25, and is provided between a superheater 26 connected to the outlet side of the furnace path 25 and an external steam turbine 30 to detect a steam turbine inlet temperature 38. It also includes a function generator 47 that determines a water supply command 48 to be sent directly to the water supply valve 24 from an external output command 39, and further comprises a function generator 47 that calculates a water supply command 48 to be sent directly to the water supply valve 24 from an external output command 39. a subtractor 57 that obtains a steam turbine inlet temperature deviation 60 by subtracting the temperature 38 and a steam turbine inlet set temperature 59 set in a setting device 58; and a controller that uses the steam turbine inlet temperature deviation 60 as a layer height control signal 63. 64, a function generator 40 for converting the output command 39 into a bed height command 41, an adder 66 for adding the bed height command 41 and the bed height control signal 63 to obtain a corrected bed height command 65, and a correction bed height command 64; A subtractor 42 that calculates a bed height deviation 43 by subtracting the command 65 and the actual bed height 34 detected by the level meter 33, and a bed material supply valve 7 or a bed material discharge valve 8 based on the bed height deviation 43. 1. A steam temperature control device for a pressurized fluidized bed boiler, comprising: a high-low monitor 44 that obtains an opening/closing command 45 or 46 to open or close one of the boilers.