JPH1033946A - Method and apparatus for control of injection amount of ammonia or denitration unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ammonia injection control method of a denitration unit capable of equalizing actual outlet NOx of the denitration apparatus in a duct by simple constitution and capable of holding the value of outlet NOx to outlet NOx set value or less and an apparatus therefor. SOLUTION: Valve travel commands 14a, 14b are outputted to flow rate adjusting valves 10a, 10b from a controller 13 on the basis of the exhaust gas flow rates 4a, 4b detected by flowmeters 3a, 3b, the inlet NOx valves 6a, 6b detected by outlet NOx meters 7a, 7b and the actual ammonia injection amt. 12 detected by an ammonia meter 11 to adjust the value travel of the flow rate adjusting valves 10a, 10b and a required amt. of ammonia is injected into a duct 1 from ammonia injection pipes 9a, 9b.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for controlling an amount of injected ammonia in a denitration apparatus.

[0002]

2. Description of the Related Art Generally, nitrogen oxides (NOx) are contained in exhaust gas discharged from a steam boiler, a gas turbine, or the like. Therefore, such NOx must be removed by a denitration device.

FIG. 6 shows an example of a conventional denitration apparatus, in which a duct 1a through which exhaust gas discharged from a gas turbine flows is connected to a duct 1b through which exhaust gas discharged from a steam boiler flows. A duct 2 through which both exhaust gases merge and flows is provided, a denitration device 2 is provided in the middle of the duct 1 and is filled with a catalyst therein, and 3a is an exhaust gas flow rate 4a flowing through the duct 1a (unit: [Nm ³ /
h]), 3b is a flow meter for detecting the flow rate 4b of exhaust gas flowing in the duct 1b (unit: [Nm ³ / h]), 5a is an inlet contained in the exhaust gas flowing in the duct 1a Inlet NOx meter for detecting NOx 6a (unit: [ppm]); 5b, inlet NOx meter for detecting inlet NOx 6b (unit: [ppm]) contained in exhaust gas flowing through the duct 1b; NOx8 contained in exhaust gas that passed through (unit: [ppm])
9 is an ammonia injection pipe for injecting ammonia (NH ₃ ) into the inlet side of the denitration device 2, 10 is a flow control valve provided in the middle of the ammonia injection pipe 9, and 11 is ammonia injection The actual ammonia injection amount 12 (unit is [kg /
h]), 13 is a flow meter 3a, 3
Exhaust gas flow rates 4a and 4b detected in b and inlet NOx total 5
Inlet NOx 6a, 6b and outlet NOx detected at a, 5b
The controller outputs an opening command 14 to the flow control valve 10 based on the outlet NOx 8 detected by the total 7 and the actual ammonia injection amount 12 detected by the ammonia meter 11.

[0004] As shown in FIG.
An adder 27 that calculates the sum of the exhaust gas flow rates 4a and 4b detected by the flow meters 3a and 3b and outputs a total exhaust gas flow rate 28;
Inlet NOx 6a, 6 detected by inlet NOx total 5a, 5b
adder 29 that calculates the sum of b and outputs total entrance NOx 30
And the total exhaust gas flow rate 28 output from the adder 27 and the total inlet NOx 30 output from the adder 29,

From the required ammonia injection amount [kg / h] = κ × total exhaust gas flow rate [Nm ³ / h] × total inlet NOx [ppm] × molar ratio (where κ is a proportional constant), the necessary ammonia injection amount 16 is calculated. An arithmetic unit 15 for obtaining and outputting the difference; a subtractor 18 for obtaining a difference between an outlet NOx 8 detected by the outlet NOx meter 7 and a preset outlet NOx set value 17 and outputting an outlet NOx deviation 19; Container 18
An integration controller 20 that integrates the outlet NOx deviation 19 output from the controller and outputs a signal 21, and converts the signal 21 output from the integration controller 20 into the required ammonia injection amount 16 output from the calculator 15. In addition, an adder 22 that outputs a corrected ammonia injection amount 23, a corrected ammonia injection amount 23 output from the adder 22,
Find the difference from the actual ammonia injection amount 12 detected in
A subtractor 24 for outputting an ammonia injection amount deviation 25; a proportional integration controller 26 for performing a proportional integration process on the ammonia injection amount deviation 25 output from the subtracter 24 and outputting an opening degree command 14 to the flow control valve 10; Is provided.

In the denitration apparatus 2 shown in FIGS. 6 and 7, ammonia is injected into the duct 1 from the ammonia injection pipe 9 and the catalyst in the denitration apparatus 2 reduces NOx contained in the exhaust gas. NOx emitted
At this time, the injection amount of ammonia is controlled in the following procedure.

That is, the exhaust gas flow rates 4a and 4b detected by the flow meters 3a and 3b are input to the controller 13, and the adder 27 of the controller 13 calculates the sum of the exhaust gas flow rates 4a and 4b. The exhaust gas flow rate 28 is output to the arithmetic unit 15 and the inlet NOx 6 detected by the inlet NOx meters 5a and 5b.
a, 6b are obtained in the adder 29, and the total entrance N
Ox 30 is output to the arithmetic unit 15, the required ammonia injection amount 16 is obtained from the equation (1) and output to the adder 22, the outlet NOx 8 detected by the outlet NOx meter 7, The difference from the preset outlet NOx set value 17 is obtained in the subtractor 18 and the outlet NOx
The deviation 19 is output to the integration controller 20, and the integration controller 2
The signal 21 output from 0 is added to the required ammonia injection amount 16 output from the arithmetic unit 15 in the adder 22, and the corrected ammonia injection amount 23 is output to the subtractor 24. The difference between the corrected ammonia injection amount 23 output from 22 and the actual ammonia injection amount 12 detected by the ammonia meter 11 is obtained,
The ammonia injection amount deviation 25 is output to the proportional integration controller 26. In the proportional integration controller 26, the ammonia injection amount deviation 25 output from the subtractor 24 is proportionally integrated, and the opening command 14 is sent to the flow rate regulating valve 10. A required amount of ammonia is injected from the ammonia injection pipe 9 into the duct 1 so that the opening degree of the flow control valve 10 is adjusted based on the opening degree command 14 and the outlet NOx 8 becomes equal to or less than the outlet NOx set value 17. Is done.

[0007]

However, as described above, the duct 1a through which the exhaust gas discharged from the gas turbine flows is connected to the duct 1b through which the exhaust gas discharged from the steam boiler flows. When merging with the duct 1 and introducing it into the denitration device 2, the state of the exhaust gas flowing into the denitration device 2 (the concentration of NOx in the exhaust gas and the flow rate of the exhaust gas) becomes difficult to be uniform particularly in the upper portion and the lower portion of the duct 1. Even if the outlet NOx 8 is equal to or less than the outlet NOx set value 17, the actual outlet NOx of the denitration device 2 may not be uniform in the duct 1, and there may be a portion partially exceeding the outlet NOx set value 17. Was.

The present invention has been made in view of the above circumstances, and has a simple structure, in which the actual outlet NOx of a denitration device can be equalized in a duct, and the ammonia injection amount control method of the denitration device can be maintained at or below an outlet NOx set value. And a device.

[0009]

According to the present invention, a duct 1a through which exhaust gas from a gas turbine flows is connected to a duct 1b through which exhaust gas from a steam boiler flows, and both exhaust gases are joined to the duct 1. A method for controlling the amount of ammonia injected into a denitration device to be introduced into a denitration device 2, comprising:
Exhaust gas flow rates 4a, 4b flowing through the insides a, 1b and the inlet NOx
6a and 6b, and the outlet NOx 8a and 8b at the upper and lower portions in the depth direction of the duct 1 on the outlet side of the denitration device 2.
And the actual ammonia injection amount 12 injected from the ammonia injection pipes 9a and 9b at the upper and lower portions in the depth direction of the duct 1 on the inlet side of the denitration device 2, and the exhaust gas flow rates 4a and 4b and the inlet NOx 6a and 6b are detected. And exit NOx8
a, 8b and the actual ammonia injection amount 12, the ammonia injection pipe 9a, the ammonia injection amount deviation 32 between the corrected ammonia injection amount 23 and the actual ammonia injection amount 12.
The basic opening command 34 for the flow control valves 10a and 10b of the gas turbine 9b is obtained, and the opening correction gains 36 and 3 for the flow control valves 10a and 10b obtained from the exhaust gas flow rate 4a of the gas turbine.
8 and the opening correction gain 44 of the flow control valves 10a and 10b determined from the outlet NOx difference correction value 42 based on the outlet NOx difference 40 between the outlet NOx 8a and 8b so that the outlet NOx difference 40 disappears. , 48 are obtained, and the opening of the flow control valves 10a, 10b is adjusted according to the opening commands 14a, 14b obtained by multiplying the basic opening command 34 by the final opening correction gains 46, 48. The present invention relates to a method for controlling the amount of ammonia injected into a denitration apparatus, which controls the amount of ammonia injected into upper and lower portions of a duct 1 in the depth direction.

Further, according to the present invention, a duct 1a through which exhaust gas from a gas turbine flows is connected to a duct 1b through which exhaust gas from a steam boiler flows, and both exhaust gases are merged into the duct 1 to the denitration device 2. A flow rate meter 3a, 3b for detecting an amount of exhaust gas 4a, 4b flowing through ducts 1a, 1b, which is an ammonia injection amount control device of a denitration device to be introduced.
And inlet NOx meters 5a and 5b for detecting inlet NOx 6a and 6b in ducts 1a and 1b, and outlet NOx 8 at the upper and lower portions in the depth direction of duct 1 on the outlet side of denitration device 2.
outlet NOx meters 7a, 7b for detecting a, 8b, and ammonia injection pipes 9a, 9a for injecting ammonia into the upper and lower portions in the depth direction of the duct 1 on the inlet side of the denitration device 2.
9b, flow control valves 10a, 10b provided in the middle of each of the ammonia injection pipes 9a, 9b,
a, an ammonia meter 11 for detecting the actual amount 12 of ammonia injected into the duct 1 from the 9b;
Exhaust gas flow rates 4a, 4b detected at a, 3b and inlet NO
x The inlet NOx 6a, 6b detected by the total 5a, 5b, the outlet NOx 8a, 8b detected by the outlet NOx total 7a, 7b, and the actual ammonia injection amount 1 detected by the ammonia meter 11.
2, the basic opening command 34 for the flow control valves 10a and 10b is obtained from the ammonia injection amount deviation 32 between the corrected ammonia injection amount 23 and the actual ammonia injection amount 12, and the flow rate obtained from the exhaust gas flow rate 4a of the gas turbine. The outlet NOx based on the opening correction gains 36, 38 of the regulating valves 10a, 10b and the outlet NOx difference 40 between the outlet NOx 8a, 8b.
Final opening correction gains 46 and 48 are obtained from the opening correction gains 44 of the flow control valves 10a and 10b obtained from the difference correction value 42 so as to eliminate the outlet NOx difference 40, and the final opening correction 34 is added to the basic opening command 34. The opening degree commands 14a and 14b obtained by multiplying the gains 46 and 48 are supplied to the flow control valves 10a and 10b.
b, and a controller 13 for output to the b.

According to the above means, the following effects can be obtained.

In the method for controlling the amount of injected ammonia in the denitration apparatus of the present invention, the exhaust gas flow rates 4a and 4b flowing through the ducts 1a and 1b and the inlet NOx 6a and 6b are detected, and the depth of the duct 1 at the exit side of the denitration apparatus 2 is detected. The outlet NOx 8a, 8b at the upper and lower portions in the vertical direction is detected, and the actual ammonia injection amount 12 injected from the ammonia injection pipes 9a, 9b at the upper and lower portions in the depth direction of the duct 1 on the inlet side of the denitration device 2 is detected. Based on the flow rates 4a, 4b, the inlet NOx 6a, 6b, the outlet NOx 8a, 8b, and the actual ammonia injection amount 12, the corrected ammonia injection amount 23
From the deviation 32 of the ammonia injection amount between the actual ammonia injection amount 12 and the flow rate adjusting valve 10 of the ammonia injection pipes 9a and 9b.
a, 10b, and the flow control valve 10 determined from the exhaust gas flow rate 4a of the gas turbine.
a, 10b, the opening correction gains 36, 38 and the outlet NOx
The final opening correction gains 46 and 48 are obtained from the opening correction gains 44 of the flow control valves 10a and 10b obtained from the outlet NOx difference correction value 42 based on the outlet NOx differences 40 of 8a and 8b so as to eliminate the outlet NOx difference 40. The flow control valves 10a, 14b are provided in accordance with the opening commands 14a, 14b obtained by multiplying the basic opening command 34 by the final opening correction gains 46, 48.
By adjusting the opening of 10b, the injection amount of ammonia in the upper and lower portions in the depth direction of the duct 1 is controlled.

In the control apparatus for controlling the amount of injected ammonia in the denitration apparatus of the present invention, the exhaust gas flow rates 4a and 4b detected by the flow meters 3a and 3b, the inlet NOx 6a and 6b detected by the inlet NOx meters 5a and 5b, and the outlet On the basis of the outlet NOx 8a, 8b detected by the NOx meters 7a, 7b and the actual ammonia injection amount 12 detected by the ammonia meter 11, the controller 13 injects ammonia into the corrected ammonia injection amount 23 and the actual ammonia injection amount 12. A basic opening command 34 for the flow control valves 10a and 10b is obtained from the amount deviation 32, and the opening correction gains 36 and 38 for the flow control valves 10a and 10b obtained from the exhaust gas flow rate 4a of the gas turbine.
Exit N based on exit NOx difference 40 between exit NOx 8a and 8b
The final opening correction gains 46 and 48 are obtained from the opening correction gains 44 of the flow control valves 10a and 10b obtained from the Ox difference correction value 42 so that the outlet NOx difference 40 is eliminated. The opening degree commands 14a and 14b obtained by multiplying the degree correction gains 46 and 48 are
a, 10b, the opening of the flow control valves 10a, 10b is adjusted based on the opening commands 14a, 14b, and a required amount of ammonia is injected into the duct 1 from the ammonia injection pipes 9a, 9b.

As a result, the duct 1a through which the exhaust gas discharged from the gas turbine flows is connected to the duct 1b through which the exhaust gas discharged from the steam boiler flows. When the exhaust gas flowing into the denitration device 2 is difficult to be uniformly distributed particularly in the upper part and the lower part in the duct 1, the actual outlet NOx 8 a, 8 b of the denitration device 2 is evenly distributed in the duct 1. That is, the output NOx setting value does not partially exceed the set value.

[0015]

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

FIGS. 1 to 5 show an embodiment of the present invention. In the drawings, the portions denoted by the same reference numerals as those in FIGS. 6 and 7 represent the same components. NOx meter 7a for detecting the outlet NOx 8a (unit: [ppm]) contained in the exhaust gas passing through the denitration device 2 at the upper and lower portions in the depth direction of the duct 1 on the side, and the exhaust gas passing through the denitration device 2 arranged an outlet NOx meter 7b outlet NOx8b (units of [ppm]) for detecting a contained, improve towards the depth of the duct 1 at the inlet side of the denitration apparatus 2, respectively the lower, ammonia (NH ₃₎ Ammonia injection pipes 9a and 9b branched from the ammonia injection pipe 9 for injection are provided.
b, flow control valves 10a, 10b are provided in the middle, and exhaust gas flow rates 4a, 4b detected by the flow meters 3a, 3b.
And the inlet NOx 6a detected by the inlet NOx meters 5a and 5b.
6b and outlet NOx 8 detected by outlet NOx meters 7a and 7b
A controller 13 is provided for outputting the opening degree commands 14a, 14b to the flow control valves 10a, 10b based on the values a, 8b and the actual ammonia injection amount 12 detected by the ammonia meter 11.

As shown in FIG. 2, the controller 13 calculates the sum of the exhaust gas flow rates 4a and 4b detected by the flow meters 3a and 3b, and outputs a total exhaust gas flow rate 28, and an inlet NOx meter 5a. , 5b to determine the sum of the inlet NOx 6a, 6b and output the total inlet NOx 30;
Based on the total exhaust gas flow rate 28 output from the adder 27 and the total inlet NOx 30 output from the adder 29,
An arithmetic unit 15 for obtaining and outputting the required ammonia injection amount 16 from the expression of [Equation 1], and an arithmetic unit 51 for obtaining and outputting the average value 52 of the outlet NOx 8a, 8b detected by the outlet NOx meters 7a, 7b. Average value 52 obtained by the arithmetic unit 51
And a preset exit NOx set value 17, and a subtractor 18 that outputs an exit NOx deviation 19, and outputs a signal 21 by integrating the exit NOx deviation 19 output from the subtracter 18. An adder 22 for adding a signal 21 output from the integral adjuster 20 to the required ammonia injection quantity 16 output from the arithmetic unit 15 and outputting a corrected ammonia injection quantity 23; Vessel 22
Subtractor 3 which calculates the difference between the corrected ammonia injection amount 23 output from the controller and the actual ammonia injection amount 12 detected by the ammonia meter 11 and outputs the ammonia injection amount deviation 32
1, a proportional-integral controller 33 for proportionally integrating the ammonia injection amount deviation 32 output from the subtractor 31 and outputting a basic opening command 34 for the flow control valves 10a and 10b, and detection by the flow meter 3a. Gas turbine exhaust gas flow 4
a function generator 35 for outputting the opening correction gain 36 of the flow control valve 10a based on the flow rate control valve 10a, and the flow control valve 10 based on the exhaust gas flow rate 4a of the gas turbine detected by the flow meter 3a.
a function generator 37 for outputting an opening correction gain 38 for b;
Exit NOx 8a, 8 detected by exit NOx total 7a, 7b
subtracter 39 for calculating the difference between the values b and outputting the exit NOx difference 40
And a function generator 41 that outputs an outlet NOx difference correction value 42 based on the outlet NOx difference 40 output from the subtractor 39.
An integration adjuster 43 that integrates the outlet NOx difference correction value 42 output from the function generator 41 and outputs an opening correction gain 44 of the flow control valves 10a and 10b so that the outlet NOx difference 40 disappears; The opening correction gain 36 of the flow control valves 10a and 10b output from the integration controller 43 is added to the opening correction gain 36 output from the function generator 35.
Adder 45 that outputs the final opening correction gain 46
And an opening correction gain 38 output from the function generator 37 to a flow control valve 1 output from the integration adjuster 43.
An adder 47 for adding the opening correction gains 44 of 0a and 10b with their signs inverted and outputting a final opening correction gain 48
And the basic opening command 34 output from the proportional-integral controller 33 and the final opening correction gain 46 output from the adder 45, and the opening command 14a is multiplied by the opening command 14a.
multiplied by the final opening correction gain 48 output from the adder 47 to the basic opening command 34 output from the proportional-integral adjuster 33, and the opening command 14b is flow-adjusted. And a multiplier 50 for outputting to the valve 10b.

The function generator 35 receives a function F ₁ (x) as shown in FIG.
₁ (x) is an opening correction gain 36 of the flow control valve 10a which is substantially proportional to an increase or decrease of the exhaust gas flow rate 4a of the gas turbine.
Represents the increasing or decreasing the, also, wherein the function generator 37 are inputted function F ₂ (x) as shown in FIG. 4, the number of F ₂ (x) is the function of the gas turbine exhaust gas This indicates that the opening correction gain 38 of the flow control valve 10b is increased or decreased in inverse proportion to the increase or decrease in the flow rate 4a.
That is, the duct 1a through which the exhaust gas discharged from the gas turbine flows is connected to the duct 1b through which the exhaust gas discharged from the steam boiler flows, and both exhaust gases are connected to the duct 1b.
When the exhaust gas from the gas turbine flows into the lower part of the duct 1 as shown in FIG. 1 when the exhaust gas flows from the gas turbine to the lower part of the duct 1 as shown in FIG. This is because the experimental results revealed that the opening degree of the regulating valve 10a should be increased and the opening degree of the flow regulating valve 10b should be decreased.

[0019] Furthermore, the function generator 41 is input function F ₃ (x), as shown in FIG. 5, the function number F ₃
(X), when the outlet NOx difference 40 is within a certain range, the outlet NOx difference correction value 42 is set to zero, the opening correction gain 44 of the flow control valves 10a and 10b is held, and the outlet NOx difference If the difference 40 exceeds a certain range,
The exit NOx difference correction value 42
The upper limit and the lower limit are determined and the output is increased and decreased within the range, and the output correction gain 44 of the flow rate regulating valves 10a and 10b is defined by the upper limit and the lower limit and is output within the range. I have.

Next, the operation of the illustrated example will be described.

The exhaust gas flow rates 4a and 4b detected by the flow meters 3a and 3b are input to a controller 13, and the adder 27 of the controller 13 calculates the sum of the exhaust gas flow rates 4a and 4b, 28 is output to the arithmetic unit 15, and the entrance NOx 6a, 6b detected by the entrance NOx total 5a, 5b.
Is obtained in the adder 29, and the total entrance NOx 30
Is output to the arithmetic unit 15, the required ammonia injection amount 16 is calculated from the equation (1), and the calculated ammonia injection amount 16 is output to the adder 22. The outlet NOx meters 7 a and 7 b detect the outlet NOx 8 a, Average value 52 of 8b is arithmetic unit 5
1 and output to the subtractor 18, where the average value 52 obtained by the arithmetic unit 51 is obtained.
And a preset exit NOx set value 17 is obtained, an exit NOx deviation 19 is output to an integration controller 20, and a signal 21 output from the integration controller 20 is added to an arithmetic unit in an adder 22. The corrected ammonia injection amount 23 is added to the required ammonia injection amount 16 output from
Is output to the subtractor 31, and the corrected ammonia injection amount 23 output from the adder 22 in the subtractor 31;
Actual ammonia injection amount 1 detected by ammonia meter 11
2 is obtained, and the ammonia injection amount deviation 32 is output to the proportional-integral controller 33, and the ammonia injection amount deviation 32 output from the subtractor 31 is proportional-integrated in the proportional-integral controller 33 to obtain the flow rate. Adjusting valves 10a, 10b
Is output to the multiplier 49 and the multiplier 50.

In the function generator 35, the flow meter 3
a, the opening correction gain 36 of the flow control valve 10a is output to an adder 45 on the basis of the exhaust gas flow rate 4a of the gas turbine detected at a.
Is output to the adder 47 based on the exhaust gas flow rate 4a of the gas turbine detected at step S4, and the difference between the outlet NOx 8a and 8b detected by the outlet NOx meters 7a and 7b is subtracted. The exit NOx difference 40 is output to the function generator 41, and the exit NOx difference correction value 42 is calculated by the integration controller 43 based on the exit NOx difference 40 output from the subtractor 39 in the function generator 41. Output NOx difference correction value 42 output from the function generator 41 in the integration controller 43.
Is integrated and the opening correction gain 44 of the flow control valves 10a and 10b is output to the adder 45 and the adder 47 so that the outlet NOx difference 40 disappears, and the output from the function generator 35 in the adder 45. Opening correction gain 3
6 is a flow control valve 10 output from the integration controller 43.
a and 10b are added to the opening correction gain 44, and the final opening correction gain 46 is output to the multiplier 49.
In the adder 47, the opening correction gain 38 output from the function generator 37 is added to the opening correction gain 44 of the flow control valves 10a and 10b output from the integration controller 43.
Is added with the sign inverted, and the final opening correction gain 48
Is output to the multiplier 50, and the basic opening degree command 3 output from the proportional-integral adjuster 33 in the multiplier 49.
4 is multiplied by the final opening correction gain 46 output from the adder 45, and the opening command 14a is
a, the opening of the flow control valve 10a is adjusted based on the opening command 14a, a required amount of ammonia is injected into the duct 1 from the ammonia injection pipe 9a, and the proportional integration is performed by the multiplier 50. The basic opening command 34 output from the adjuster 33 is multiplied by the final opening correction gain 48 output from the adder 47 to obtain the opening command 14b.
Is output to the flow control valve 10b, the opening of the flow control valve 10b is adjusted based on the opening command 14b, and a required amount of ammonia is injected into the duct 1 from the ammonia injection pipe 9a.

As a result, the duct 1b through which the exhaust gas discharged from the gas turbine flows is connected to the duct 1b through which the exhaust gas discharged from the steam boiler flows. When the gas is introduced into the denitration apparatus 2, the state of the exhaust gas flowing into the denitration device 2 (N in the exhaust gas)
Even if the concentration of Ox or the flow rate of the exhaust gas is difficult to be uniform in the duct 1, especially in the upper part and the lower part, the denitration device 2
The actual outlet NOx 8a, 8b becomes uniform in the duct 1 and does not partially exceed the outlet NOx set value.

As described above, the denitration apparatus 2 has a simple configuration.
The actual outlet NOx 8a, 8b can be equalized in the duct 1 and kept below the outlet NOx set value.

It should be noted that the method and apparatus for controlling the amount of injected ammonia in the denitration apparatus of the present invention are not limited to the above-described illustrated examples, and that various modifications can be made without departing from the gist of the present invention. Of course.

[0026]

As described above, according to the method and apparatus for controlling the amount of injected ammonia in the denitration apparatus of the present invention, the actual outlet NOx 8a, 8b of the denitration apparatus 2 can be configured with a simple configuration.
Can be equalized in the duct 1 and can be maintained at the outlet NOx set value or less.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of an example of an embodiment of the present invention.

FIG. 2 is a block diagram illustrating details of a controller according to an example of an embodiment of the present invention.

FIG. 3 is a diagram showing a function F ₁ (x) set in a function generator 35 shown in FIG. 2;

FIG. 4 is a diagram showing a function F ₂ (x) set in a function generator 37 shown in FIG. 2;

FIG. 5 is a diagram showing a function F ₃ (x) set in a function generator 41 shown in FIG. 2;

FIG. 6 is a schematic configuration diagram of a conventional example.

FIG. 7 is a block diagram showing details of a controller in a conventional example.

[Explanation of symbols]

 1 Duct 1a Duct 1b Duct 2 Denitrator 3a Flow meter 3b Flow meter 4a Exhaust gas flow 4b Exhaust gas flow 5a Inlet NOx meter 5b Inlet NOx meter 6a Inlet NOx 6b Inlet NOx 7a Outlet NOx meter 7b Outlet NOx meter 8a Outlet NOx 8a Out NOx meter Ammonia injection pipe 9b Ammonia injection pipe 10a Flow control valve 10b Flow control valve 11 Ammonia meter 12 Actual ammonia injection amount 13 Controller 14a Opening command 14b Opening command 16 Required ammonia injection quantity 32 Ammonia injection quantity deviation 34 Basic opening command 36 Opening correction gain 38 Opening correction gain 40 Exit NOx difference 42 Exit NOx difference correction value 44 Opening correction gain 46 Final opening correction gain 48 Final opening correction gain

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code Agency reference number FI Technical indication F23J 15/00

Claims (2)

[Claims] 1. A denitration apparatus in which a duct (1a) through which exhaust gas from a gas turbine flows is connected to a duct (1b) through which exhaust gas from a steam boiler flows, and both exhaust gases join the duct (1). A method for controlling the amount of ammonia injected into a denitration apparatus to be introduced into (2), wherein the flow rate of exhaust gas flowing through ducts (1a) and (1b) (4a)
(4b) and the inlet NOx (6a) (6b) are detected, and the outlet NOx (8a) (8b) at the upper and lower portions in the depth direction of the duct (1) on the outlet side of the denitration device (2) are detected.
Detecting the actual ammonia injection amount (12) injected from the ammonia injection pipes (9a) and (9b) at the upper and lower portions in the depth direction of the duct (1) on the inlet side of the denitration device (2);
Exhaust gas flow rate (4a) (4b) and inlet NOx (6a)
Based on (6b), the outlet NOx (8a) (8b) and the actual ammonia injection amount (12), the ammonia injection amount deviation (32) between the corrected ammonia injection amount (23) and the actual ammonia injection amount (12) is used Injection tube (9a)
The flow rate control valves (10a) (10b) obtained from the flow rate control valves (10a) and (10b) of (9b) and the exhaust gas flow rate (4a) of the gas turbine are obtained.
Opening correction gains (36) and (38) and the outlet NOx (8
a) Exit NOx based on exit NOx difference (40) of (8b)
The final opening correction gains (46) and (4) are obtained from the opening correction gains (44) of the flow control valves (10a) and (10b) obtained from the difference correction value (42) so as to eliminate the outlet NOx difference (40).
8), and the opening command (1) obtained by multiplying the basic opening command (34) by the final opening correction gains (46) and (48).
4a) and (14b), the flow control valves (10a) (10
A method for controlling the amount of ammonia injected into a denitration apparatus, wherein the amount of ammonia injected into the upper and lower portions of the duct (1) in the depth direction is controlled by adjusting the opening degree of b). 2. A denitration apparatus in which a duct (1a) through which exhaust gas from a gas turbine flows is connected to a duct (1b) through which exhaust gas from a steam boiler flows, and both exhaust gases join the duct (1). An ammonia injection amount control device for a denitration device to be introduced into (2), wherein an exhaust gas flow rate flowing through ducts (1a) and (1b) (4a)
Flowmeters (3a) and (3b) for detecting (4b), and NOx inlets (6a) and (6) in ducts (1a) and (1b)
Inlet NOx meters (5a) and (5b) for detecting b) and outlet NOx meters (8a) and (8b) for detecting the outlet NOx (8a) and (8b) at the upper and lower portions in the depth direction of the duct (1) on the outlet side of the denitration device (2). (7a) and (7b), ammonia injection pipes (9a) and (9b) for injecting ammonia at the upper and lower portions in the depth direction of the duct (1) on the inlet side of the denitration device (2), and each ammonia injection pipe ( 9a) (9b) A flow control valve (10a) (10b) provided in the middle, and a duct (1) from each ammonia injection pipe (9a) (9b).
An ammonia meter (11) for detecting the actual ammonia injection amount (12) injected into the inside, an exhaust gas flow rate (4a) (4b) detected by the flow meter (3a) (3b), and an inlet NOx meter (5a) The inlet NOx (6a) (6b) detected at (5b) and the outlet NOx meter (7
a) Outlet NOx detected in (7b) (8a) (8b)
And the actual ammonia injection amount (12) detected by the ammonia meter (11).
From the deviation (32) of the ammonia injection amount between 3) and the actual ammonia injection amount (12), the flow control valves (10a) (10b)
And the flow control valve (10a) obtained from the exhaust gas flow rate (4a) of the gas turbine.
The exit NOx difference (40) disappears from the exit NOx difference correction value (42) based on the opening correction gains (36) and (38) of (10b) and the exit NOx difference (40) of the exit NOx (8a) and (8b). The final opening correction gain (4) is obtained from the opening correction gain (44) of the flow control valves (10a) (10b) obtained as described above.
6) (48) is obtained, and the opening commands (14a) (14b) obtained by multiplying the basic opening command (34) by the final opening correction gains (46) (48) are used as the flow control valves (10a) ( 1
And a controller (13) for outputting the ammonia injection amount to the denitration apparatus.