KR20100063387A - Automatic control device for nox concentration and method thereof - Google Patents

Abstract

PURPOSE: A device and a method for automatically controlling the concentration of NOx(Nitrogen Oxide) of a gas, capable of automatically reducing the concentration of NOx are provided to prevent unstable combustion as integral action logic suppresses the rapid operation of a valve during an auto correction process. CONSTITUTION: A device for automatically controlling the concentration of NOx of a gas comprises a controller(20) and a fuel distributing valve unit(30). The controller comprises a comparing and computing unit, an integral controller, and a protector. The comparing and computing unit comprises a set concentration value and a present value of the NOx. The integral controller corrects relative output for controlling the fuel distributing valve according to comparison deviation. The protector senses NOx density decrease degree and unstable combustion and stops correction. The fuel distributing valve unit is controlled by the controller.

Description

Automatic control device for NOx concentration and method according to gas turbine

The present invention relates to the field of gas turbines, and more specifically, to calculate the deviation between the nitrogen oxide emission concentration and the set nitrogen oxide concentration, and to adjust the opening degree of the fuel distribution valve by correcting the relative output signal when the emission concentration is higher than the set value. It automatically reduces the concentration of NOx produced during combustion during gas turbine operation.In the process of automatic compensation, the valve is not operated suddenly through the integral operation logic so that the flame state changes suddenly during combustion. Automatic control device and method for nitrogen oxide concentration of gas turbine, which can prevent the occurrence of instability in advance and operate only within the range that does not impair combustion stability by detecting the abnormality of combustion condition and adding the logic stop condition. It is about.

The gas turbine power generation system is mainly composed of a compressor, a combustion chamber, a gas turbine, and a generator. Among them, the compressor, the gas turbine, and the generator are connected to the same shaft and rotate at the same speed during operation.

When the gas turbine is operated for power generation, a large amount of air flows from the outside of the gas turbine into the combustion chamber in the gas turbine and is burned at high temperature together with natural gas as a fuel. Reacts at high temperatures to form nitrogen oxides.

The nitrogen oxides produced in this way are polluted with the atmosphere while being discharged into the atmosphere. In Korea, nitrogen oxide concentration has been regulated by law.

Under the nitrogen oxide concentration regulation before July 1, 2007, it was possible to cope with the current technology according to the three-hour grace clause and the use of more relaxed data after the start of operation. Measures such as manual adjustments and deratings were able to comply with regulatory values.

However, under the nitrogen oxide concentration and total regulation, which came into effect on July 1, 2007, the provision of the post-employment deferral criteria clause has been removed, and the necessity of further strengthening the concentration and total amount of nitrogen oxide has emerged.

As one of the techniques for suppressing the production of such nitrogen oxides, a dry low nitrogen oxide gas turbine combustor of a lean premixed combustion method is often used.

However, the above-mentioned dry lean mixed nitrogen gas turbine of the lean mixed combustion method is controlled only by the mechanical mechanism, and thus is influenced by many factors such as air temperature, atmospheric humidity, compressor performance, combustion chamber state, fuel burner state, and the like. There is a problem that does not respond properly to the environment of the gas turbine combustor.

An object of the present invention is to solve the conventional problems as described above, by calculating the deviation between the nitrogen oxide emission concentration and the set nitrogen oxide concentration, and correcting the relative output signal when the emission concentration higher than the set value to distribute the fuel The present invention provides an apparatus and a method for automatically controlling nitrogen oxide concentration of a gas turbine, by automatically reducing the concentration of nitrogen oxides (NOx) generated during combustion during gas turbine operation by adjusting the opening degree of a valve.

Another object of the present invention is to configure the valve so that it does not operate suddenly through the integral operation logic during the automatic calibration process, so that the flame state changes suddenly during operation to prevent the occurrence of combustion instability. To provide a control apparatus and method.

It is yet another object of the present invention to provide an apparatus and method for automatically controlling the nitrogen oxide concentration of a gas turbine, which detects abnormality of the combustion state in advance and also adds a logic-correction stop condition so that it operates only within a range that does not impair combustion stability. There is.

As a means for achieving the above object, the configuration of the apparatus of the present invention reads the combustion chamber fuel injection differential pressure signal using a signal input from the sensor unit to determine whether the differential pressure is less than a certain value (2 bar), and emergency control. It is determined whether the operation signal is a logic '1', it is determined whether the PLS signal is a logic '1', and it is determined whether the concentration value of the nitrogen oxide is above a predetermined value (200 ppm) by reading the concentration value of the nitrogen oxide, and the nitrogen It is judged whether the fall trend of the oxide concentration value is more than a certain value (10 ppm) per minute, the combustion chamber fuel injection differential pressure is less than a certain value (2 bar), the emergency control operation signal is logic '1' and the PLS signal is logic '1'. If the concentration of nitrogen oxide is more than a certain value (200ppm) or if the concentration of nitrogen oxide is more than a certain value (10ppm) per minute, the correction value is set to '0' and the concentration of nitrogen oxide is decreased. Trend per minute If it is not more than 10ppm, calculate the target value-current value, output the correction value using the integral calculation logic, read the generator output, add the correction value, and adjust the fuel distribution valve opening reference value according to the corrected value. And a control unit for setting and controlling the fuel distribution valve, and a fuel distribution valve unit controlled by the control unit.

In the configuration of the apparatus of the present invention, the control unit may control the reduction of nitrogen oxides by inducing combustion of fuel relative to the amount of air by adding the correction value to the existing fuel distribution valve opening reference value to open the fuel distribution valve further. desirable.

As a means for achieving the above object, the configuration of the method of the present invention comprises the steps of: reading a combustion fuel injection differential pressure signal to determine whether the differential pressure is less than a constant value (2 bar); Determining whether the emergency control operation signal is logic '1' when less than (2bar), and determining whether the PLS signal is logic '1' when the emergency control operation signal is logic '1', and nitrogen oxide Determining whether or not the concentration value of nitrogen oxide is more than a certain value (200ppm) by reading the concentration value of, and if the concentration value of nitrogen oxide is not more than a certain value (200ppm) Determining whether or not a constant value (10ppm) or more per minute, the combustion chamber fuel injection differential pressure is less than a certain value (2bar), the emergency control operation signal is a logic '1' and the PLS signal is a logic '1' or the concentration of nitrogen oxides This constant (200 ppm) or when the concentration of nitrogen oxide is lower than the constant value per minute (10ppm), the correction value is set to '0', and the concentration of nitrogen oxide is lowered by the constant value per minute (10 ppm). Calculating the deviation between the target value and the present value (target value-present value) and outputting the correction value using the integral calculation logic, reading the generator output and summing up the correction value, if not abnormal; And setting the fuel distribution valve opening reference value according to the corrected value and controlling the fuel distribution valve.

In the configuration of the method of the present invention, the above-described correction value summing step adds the correction value to the existing fuel distribution valve opening reference value to open the fuel distribution valve further, thereby inducing the burning of the fuel relative to the amount of air and reducing the nitrogen oxides. It is preferable if possible.

The present invention calculates the deviation between the nitrogen oxide emission concentration and the set nitrogen oxide concentration, and corrects the relative output signal when the emission concentration is higher than the set value, thereby generating the fuel during the combustion process by adjusting the opening of the fuel distribution valve. It automatically reduces the concentration of NOx, and the valve is not operated suddenly through the integral operation logic during the automatic calibration process, so that the flame state changes suddenly during operation, preventing the occurrence of combustion instability in advance. By detecting the abnormality of the combustion condition in advance and adding a logic correction stop condition, it has the effect of operating only within the range that does not impair the combustion stability.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the accompanying drawings in order to describe in detail enough to enable those skilled in the art to easily carry out the present invention. . Other objects, features, and operational advantages, including the purpose, operation, and effect of the present invention will become more apparent from the description of the preferred embodiments.

For reference, the embodiments disclosed herein are only presented by selecting the most preferred embodiment in order to help those skilled in the art from the various possible examples, the technical spirit of the present invention is not necessarily limited or limited only by this embodiment Rather, various changes, additions, and changes are possible within the scope without departing from the spirit of the present invention, as well as other equivalent embodiments.

1 is a block diagram of an apparatus for automatically controlling the nitrogen oxide concentration of a gas turbine according to an embodiment of the present invention.

As shown in Figure 1, the configuration of the automatic control apparatus for nitrogen oxide concentration of the gas turbine according to an embodiment of the present invention, the control unit (10), the control unit connected to the sensor unit (20) ( 20) and the fuel distribution valve unit 3 connected to the control unit 20.

The configuration of the control unit 20 includes a comparison operation unit for receiving and comparing a concentration value and a current value of nitrogen oxide, an integral controller for correcting a relative output used for fuel distribution valve control according to the deviation, and nitrogen oxide. It includes a protector that stops calibration by detecting the trend of concentration drop and instability of combustion in advance.

2 is an operation flowchart of a method for automatically controlling the nitrogen oxide concentration of a gas turbine according to an embodiment of the present invention.

As shown in FIG. 2, the method for automatically controlling the nitrogen oxide concentration of a gas turbine according to an embodiment of the present invention includes reading a combustion chamber fuel injection differential pressure signal (S10) and a differential pressure from the combustion chamber fuel injection differential pressure signal. Determining whether it is less than 2 bar (S20), and when the differential pressure is less than a predetermined value (2 bar) from the combustion chamber fuel injection differential pressure signal, determining whether the emergency control operation signal is a logic '1' (S30), Determining whether the PLS signal is a logic '1' when the emergency control operation signal is a logic '1', reading a concentration value of nitrogen oxides (S50), and a concentration value of the nitrogen oxides; The step (S60) of determining whether or not the predetermined value (200ppm) or more, and when the concentration value of the nitrogen oxide is not more than the predetermined value (200ppm) the fall trend of the nitrogen oxide concentration value is more than a predetermined value (10ppm) per minute Step S70 of determining whether the combustion chamber fuel injection difference It is less than this value (2bar), emergency control operation signal is logic '1', PLS signal is logic '1', nitrogen oxide concentration value is more than certain value (200ppm) or nitrogen oxide concentration value is falling per minute. When the correction value is set to '0' when the value is more than a predetermined value (10 ppm) (S120), and when the falling trend of the concentration value of the nitrogen oxide is not more than the predetermined value (10 ppm) per minute, the target value and the present value Calculating a deviation (target value-present value) (S80), outputting a correction value using integration calculation logic according to the target value-present value (S90), and reading a generator output (S150). ), Adding the correction value to the generator output value (S140), setting the fuel distribution valve opening reference value according to the corrected value (S160), and adjusting the fuel distribution valve according to the fuel distribution valve opening reference value. Control step S70 is made.

By the above configuration, the operation of the nitrogen oxide concentration automatic control apparatus and method of the gas turbine according to an embodiment of the present invention is as follows.

In order to reduce the nitrogen oxides by properly adjusting the pressure in the combustion chamber of the gas turbine, the pressure of the natural gas, which is the fuel and the air flowing into the combustion chamber of the gas turbine, must be properly adjusted. Since the inflow of air cannot be artificially adjusted, the inflow of natural gas, which is a fuel, must be artificially adjusted. In other words, since it is impossible to control the amount of air, it is necessary to appropriately distribute the pressure and adjust the pressure of natural gas, which is a fuel supplied to the combustion chamber, in order to suppress the generation of nitrogen oxides through optimum combustion. .

The pressure of natural gas varies according to weather (moisture, atmospheric pressure), compressor performance, combustion chamber conditions, etc., and it is most important to control the opening of the fuel distribution valve so that the flame can be formed as short and wide as possible to reduce nitrogen oxides.

First, the control unit 20 reads the combustion chamber fuel injection differential pressure signal from the sensor unit 10 (S10), and determines whether the differential pressure is less than a predetermined value (2 bar) from the combustion chamber fuel injection differential pressure signal (S20).

When the combustion chamber fuel injection differential pressure is less than a predetermined value (2 bar), the control unit 20 determines whether the emergency control operation signal is a logic '1' by using the signal input from the sensor unit 10 (S30).

When the emergency control operation signal is a logic '1', the controller 20 determines whether the PLS signal is a logic '1' (S40).

Then, the control unit 20 reads the concentration value of the nitrogen oxide from the sensor unit 10 (S50), and determines whether the concentration value of the nitrogen oxide is equal to or more than a predetermined value (200 ppm) (S60).

If the concentration value of the nitrogen oxide is not more than a predetermined value (200ppm), the control unit 20 determines whether the falling trend of the nitrogen oxide concentration value is more than a predetermined value (10ppm) per minute (S70).

In the above process, the combustion chamber fuel injection differential pressure is less than a certain value (2bar), the emergency control operation signal is logic '1' and the PLS signal is logic '1', or the concentration value of the nitrogen oxide is more than a certain value (200ppm), When the falling trend of the concentration value of the nitrogen oxide is more than a predetermined value (10 ppm) per minute, the control unit 20 sets the correction value to '0' (S120).

If the decrease in the concentration value of the nitrogen oxide is not more than a certain value (10 ppm) per minute, the control unit 20 calculates the deviation (target value-present value) of the target value and the present value (S80) The correction value is output by using the integral operation according to the deviation between the value and the present value (target value-present value) (S90).

In addition, the control unit 20 reads the generator output from the sensor unit 10 (S150).

Next, the controller 20 adds the correction value to the generator output value (S140), sets the fuel distribution valve opening reference value according to the corrected value (S160), and adjusts the fuel distribution valve according to the fuel distribution valve opening reference value. Control (S70). In this case, the correction value is added to the existing fuel distribution valve opening reference value to open the fuel distribution valve further, thereby inducing burned combustion of the fuel relative to the amount of air and reducing the nitrogen oxides.

1 is a block diagram of an apparatus for automatically controlling the nitrogen oxide concentration of a gas turbine according to an embodiment of the present invention.

2 is an operation flowchart of a method for automatically controlling nitrogen oxide concentration of a gas turbine according to an embodiment of the present invention.

Explanation of symbols on the main parts of the drawings

10: sensor unit 20: control unit

30: fuel distribution valve

Claims (4)

By reading the fuel injection differential pressure signal from the combustion chamber, it is determined whether the differential pressure is less than a certain value (2 bar) by using the signal input from the sensor unit, it is determined whether the emergency control operation signal is a logic '1', and the PLS signal is a logic ' 1 ', determine whether the concentration of nitrogen oxide is above a certain value (200ppm) by reading the concentration of nitrogen oxide, and whether the decrease in the concentration of nitrogen oxide is above a certain value (10ppm) per minute. The combustion chamber fuel injection differential pressure is below a certain value (2bar), the emergency control operation signal is logic '1', the PLS signal is logic '1', the concentration value of the nitrogen oxide is above the certain value (200ppm) or The correction value is set to '0' when the decrease in concentration value is above a certain value (10ppm) per minute, and the target value when the decrease in concentration of nitrogen oxide is not above a certain value (10 ppm) per minute. Calculate current value and integrate calculation logic And using the output of the correction value, and reads the generator output summing the correction value, and sets the fuel distribution valve opening reference value based on the correction value, and controlling fuel distribution valve control unit, An apparatus for automatically controlling nitrogen oxide concentration of a gas turbine, comprising a fuel distribution valve part controlled by the control unit. The method of claim 1, The control unit, by adding the correction value to the existing fuel distribution valve opening reference value to open the fuel distribution valve further by inducing the burning of the fuel relative to the amount of air to reduce the nitrogen oxides of the gas turbine characterized in that the control Nitrogen oxide concentration automatic control device. Reading the combustion chamber fuel injection differential pressure signal to determine whether the combustion chamber fuel injection differential pressure is less than a predetermined value (2 bar); Determining whether the emergency control operation signal is a logic '1'; Determining whether the PLS signal is a logic '1'; Reading the concentration value of the nitrogen oxides and determining whether the concentration value of the nitrogen oxides is above a predetermined value (200 ppm); Determining whether the concentration of nitrogen oxide is less than a predetermined value (10 ppm) per minute when the concentration of the nitrogen oxide is not more than a predetermined value (200 ppm); Combustion chamber fuel injection differential pressure is below 2 bar, emergency control operation signal is logic '1', PLS signal is logic '1', nitrogen oxide concentration is above certain value (200ppm) or nitrogen oxide concentration is falling Setting the correction value to '0' when the trend is more than a certain value (10 ppm) per minute, Calculating a target value-present value and outputting an integral calculation value according to the target value-present value when the decreasing trend of the nitrogen oxide concentration value is not more than a predetermined value (10 ppm) per minute; Summing the integral calculation output values when the combustion chamber fuel injection differential pressure is not less than a predetermined value (2 bar); Reading the generator output, Setting a fuel distribution valve opening reference value when the correction value is set to '0', the integral calculation output value is summed, or the generator output is read; And controlling the fuel distribution valve according to the fuel distribution valve opening degree reference value. The method of claim 3, wherein In the step of adding the correction value, the gas turbine is characterized in that nitrogen oxide is reduced by inducing combustion of fuel relative to the amount of air by adding the correction value to the existing fuel distribution valve opening reference value to open the fuel distribution valve further. Automatic control method of nitrogen oxide concentration of

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