KR840000688B1 - Revision method of caloty - Google Patents

Abstract

The device is comprised of a water-fuel ratio controller (M1), an oxygen controller (M2), a fuel flux controller (M3), and an air flux controller (M4). The controllers have an integral function, a manual/auto switching function, and an output tracking function. The water-fuel ratio controller(M1) generates a water-fuel ratio revision signal (K1) according to the difference between a steam temperature-detecting signal and a predetermined value.

Description

Calorie Correction Method

1 is a conceptual diagram of a thermal power plant control device using a supercritical pressure boiler.

2 is an apparatus diagram to which the method of the present invention is applied.

3 is a block diagram of a sequence control circuit combined with the apparatus of FIG.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a calorie correction method at the time of fuel change in an automatic plant control apparatus (A. P. C) of a supercritical pressure boiler.

Supercritical boilers do not have a drum, so the processor responds faster than a drum boiler.

Therefore, in the case of controlling a thermal power plant using a supercritical pressure boiler, an automatic plant control unit (A. P. C) combining a turbine control unit and a boiler control unit (A. B. C) is used.

The conceptual configuration of A. P. C is shown in Figure 1, and the generator output command receives a number of corrections and sends a master signal to all control loops.

In drum type boilers, the water supply control loop can be treated as an independent roof because it has little interference with steam pressure or steam temperature. However, in supercritical boilers, the interference between water supply, steam pressure and steam temperature is strong, and water supply control It cannot be separated from the loop and the fuel control loop.

The relationship between the water supply control loop and the fuel control loop is made through a water fuel ratio controller for correcting the water fuel ratio, and when the processor is constant, the ratio of the water supply amount and the fuel flow rate, that is, the fuel consumption ratio is always constant.

And the plant is designed so that the fuel consumption ratio at this time will be one. When coal is used as the fuel, the fuel flow signal is a value obtained by multiplying the amount of coal supplied by the calorie value of coal.

If the quality of coal changes during the operation of the plant, the calorie value is different from the original setting value, so the operating point of the fuel consumption controller is inclined to absorb the error, which causes problems in maintaining the AP C in good controllability. .

To avoid tilting the operating point of the fuel efficiency controller, you can correct the calorie value according to the change in coal, but if you change the calorie value suddenly, the output of the fuel control loop can change suddenly, which can cause external factors to the processor. It takes a long time to change calories slowly so as not to cause a factor.

It is an object of the present invention to provide a method for quickly correcting calorie values without giving external factors to the processor.

The present invention allows to change the output of the fuel consumption controller and the oxygen amount controller in accordance with the calorie value correction.

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

2 is a block diagram of an apparatus to which the method of the present invention is applied.

In FIG. 2, M ₁ is a fuel consumption controller, M ₂ is an oxygen amount controller, M ₃ is a fuel flow controller, and M ₄ is an air flow controller.

These controllers have proportional, integral, manual / automatic switching, and output tracking. M ₅ is a calorie setting device, for example, analog and memory, and its contents change depending on the increase and decrease command signals A and B. FIG. M ₆ -M ₈ is an operator.

The fuel efficiency controller M ₁ outputs the fuel temperature correction signal K ₁ according to the steam temperature detection signal and the set value and difference.

The fuel efficiency adjustment signal K ₁ is calculated with the master signal Z given at the front end in the calculator M ₆ .

The master signal Z is the same as the master signal given to the feedwater flow control loop at the front end, that is, the feedwater command.

The output signal K ₁ Z of the calculator M ₆ is given to the fuel flow controller M ₃ as the fuel command signal FFD.

The fuel flow controller M ₃ is given as the fuel flow signal FF by the coal quantity X and the enemy K ₂ X of the calorie set value K ₂ in the calculator M ₇ .

The fuel flow controller M ₃ outputs a fuel flow operation signal in accordance with the difference between these two signals.

The fuel command signal FFD and the fuel flow signal FF are given as correction signals to the fuel efficiency controller M ₁ .

The fuel consumption controller M ₁ matches the fuel command signal FFD with the fuel flow signal FF when the tracking function is activated, and sets the difference between the two input signals of the fuel flow controller M ₃ to zero.

_One of the features of the present invention is that the fuel command signal FFD and the fuel flow rate signal FF are applied to the fuel efficiency controller M ₁ as a correction signal, and both signals are matched by the tracking function.

The oxygen amount controller M ₂ outputs an oxygen amount correction signal K ₃ in accordance with the difference between the signal detecting the oxygen amount in the fuel gas and the set value.

The calculator M ₈ supplies the oxygen amount correction signal K ₃ to the fuel command signal FFD, obtains the air command signal AFD (K ₁ K ₃ Z), and gives it to the air flow controller M ₄ as a master signal.

The air flow rate detection signal Y is given to the air flow rate controller M _{4 as} the air flow rate signal AF.

The air flow controller M ₄ outputs an air flow manipulation signal in accordance with the difference between these two signals.

The air command signal AFD and the air flow signal AF are also given to the oxygen amount controller M ₂ as a correction signal.

The oxygen amount controller M ₂ matches the air command signal AFD with the air signal AF when the tracking function is activated to zero the difference between the two input signals of the air flow controller M ₄ .

It is another feature of the present invention that the air command signal AFD and the air flow rate signal AF are given to the oxygen amount controller M ₂ as a correction signal and the two signals are matched by the tracking function.

The operation of the device configured as described above is as follows.

Normally, each controller is in an automatic state, performs a proportional integrator, and performs fuel flow control and air flow control in accordance with the master signal.

If the coal with the same calories as set in the calorie set M ₅ is supplied to the boiler and the processor is in a constant state, the water fuel ratio is _{1, and} the output signal of the water fuel ratio controller M ₁ is correspondingly rated. 50% of the output.

When the quality of coal changes and the calorie changes in the set value K ₂ , the energy applied to the water changes and thus the steam temperature changes, so that the output signal of the fuel efficiency controller M ₁ changes, and accordingly the output signal of the fuel flow controller M ₃ changes to supply coal. The amount is changed so that there is no energy change due to calorie change.

When the processor is made constant again by this operation, the output signal of the fuel efficiency controller M ₁ is changed in a predetermined state (50%) as much as the calorie of coal has changed.

The output signal of the fuel efficiency controller M ₁ is less than 50% when the calories are increased and more than 50% when the calories are reduced.

In addition, the output signals of the oxygen flow controller M ₂ and the air flow controller M ₄ have new values.

At this time, the following relationship is established at the input side of the fuel flow controller M _{3 and} the input side of the air flow controller M ₄ , respectively.

K ₁ Z = K ₂ X... … … … (One)

K ₁ K ₃ Z = Y... … … … (2)

In this state, the set value K ₂ of the calorie setter M ₅ is corrected according to the quality of the coal.

Then, according to the method of the present invention, the output signal of the fuel consumption controller M ₁ is corrected by the ratio of the correction rate of the calorie setting value K _{2 to} the inverse ratio.

That is, when K ₂ is K ' ₂ , K _{1 is set} to K ₁ · K' ₂ / K ₂ , and K _{3 is set} to K ₃ · K ₂ / K ' ₂ .

This way,

It becomes

The fuel flow controller M ₃ operates according to the difference between FFD and FF, and the air flow controller M ₄ operates according to the difference between AFD and Y.

These cars are

It becomes

That is, the deviation input signals of both controllers are zero.

Therefore, the output signal of both controllers does not change, and no external influence is given to the processor. In other words, even if calorie correction is performed quickly, it does not affect the outside of the processor.

The output signal of the fuel efficiency controller M ₁ increases or decreases in response to the increase or decrease of the calorie setting value, but this is smaller than 50% when the calories are high and greater than 50% when the calories are low before correction. The output signal of the fuel efficiency controller M ₁ returns to 50%.

Therefore, returning the operating point of the fuel consumption controller M ₁ to the origin brings about good controllability.

Correction of the output signals of the water-fuel ratio controller M ₁ and the oxygen amount controller M ₂ can be easily performed by using the tracking function.

That is, the number of fuel controller when in the tracking mode Eau (tracking mode) of M _1, when an output signal when the match fuel command signal FFD is so matched to be the output signal K ₁ is changed to the fuel flow rate signal FF to K _'1,

K ' ₁ Z = K' ₂ X... … … … … (8)

In the formula (1),

If the output signal at the completion of tracking in the oxygen controller M ₂ is set to K ' ₃ ,

K ' ₁ K' ₃ Z = Y... … … … … (11)

In the formulas (2), (9) and (10),

It becomes

Such correction can be automated by the following means.

3 shows an example of a sequence control circuit for automatically performing calorie correction.

In FIG. 3, R _O , R ₂ and R ₅ are OR circuits, R ₁ , R ₃ and R ₄ are AND circuits, and T is an off relay timer.

The calorie correction command is given to the end circuit R _{1 due} to the water fuel ratio, that is, the output signal of the water fuel ratio controller M ₁ has exceeded a predetermined upper and lower limit, or the manipulator is operated.

The AND circuit R ₁ is opened when the calorie correction permission condition is established, that is, when the processor is in a constant state, and the calorie correction command is given to the AND circuits R ₃ and R ₄ through the OR circuit R ₂ .

Since either of the end circuits R ₃ and R ₄ is open depending on whether the fuel consumption ratio is greater than or less than 1, the calorie increase command A or the calorie decrease command B is output through the open end circuit.

The output signal of the AND circuit R ₃ or R ₄ is output as the tracking command CD and the manual switching command EF via the OR circuit R ₅ and the off relay timer T and fed back to the OR circuit R ₂ .

This feedback holds the output signal of the OR circuit R ₂ .

The calorie increase command A and the calorie decrease command B are given to the calorie setter M ₅ and change the set value.

As a result, the output signal of the calorie setter M ₅ changes, so that the output signal FF of the calculator M ₇ changes.

The tracking commands C and D are given to the fuel consumption controller M ₁ and the oxygen amount controller M ₂ , respectively, and they are the tracking mode.

Accordingly, the fuel consumption controller M ₁ changes the output signal K _{1 such} that the fuel command signal FFD matches the fuel flow signal FF, and the oxygen amount controller M ₂ outputs the output signal K _{3 such} that the air command signal AFD matches the air flow signal AF. Change.

Manual switching commands E and F are given to the fuel flow controller M ₃ and the air flow controller M ₄ , respectively, and they are the manual control mode.

In the manual control mode at this time, since the operator does not perform an output adjustment operation, the output signals of both controllers remain unchanged.

Accordingly, both controllers do not operate due to the deviation of the input signal generated during tracking.

By tracking number fuel controller output signal, that is the fuel economy of the M ₁ is passed close to 1, 1 ± Δ of, the calories between not fit (sense) within the command A (B) is continued, so we generated, values calorie setting Calibration continues.

As a result, the output signal of the fuel consumption controller M ₁ was closer to 1, finally within 1 ± Δ, while the calorific command (A) was extinguished, and the change in the calorie setting value was stopped.

When the caloric symptom (decrease) command A (B) is extinguished, the tracking command C.D and the manual switching command E.F are extinguished after a certain time by the action of the off-relay timer T, and each controller is returned to the automatic control state.

The time limit of the off relay timer T is determined to be sufficient to complete tracking, but may be omitted if the tracking speed is fast.

By combining the apparatus of FIG. 3 with the apparatus of FIG. 2 in this manner, calorie correction is automatically and quickly performed without affecting the processor externally.

Another phosphate group M ₆ . M ₇ . M ₈ may be substituted with an adder.

The sequence control can be implemented in various ways, such as by a program.

In addition, although the manual control mode was used to invariably hold the output signals of the fuel flow controller M ₃ and the air flow controller M ₄ during tracking, the output monitoring function may be used.

Thus, according to this invention, the method which can perform calorie correction quickly can be performed, without affecting the exterior to a processor.

Using the method of the present invention, it is possible to effectively control a thermal power plant using a supercritical pressure boiler for coal.

Claims (1)

A fuel consumption controller that provides fuel command signals by correcting the fuel consumption signal by outputting the master signal of the water supply flow control loop by the output signal, and a fuel directing signal including the fuel command signal and a calorie set point term are provided based on the difference between the two signals. A fuel flow controller for controlling the fuel flow rate, an air amount controller for correcting the oxygen amount based on an output signal and adjusting the amount of oxygen as an air command signal, and air based on the difference between the signal corresponding to the air command signal and the air flow rate signal. In the calorie correction method by an automatic plant control apparatus of a supercritical pressure boiler having an air flow rate controller for controlling the flow rate, when the calorie setting value of the fuel is corrected, the output signal of the water fuel ratio controller and the calorie setting value Fill in fuel flow controller by calibrating at the same rate A calorie correction method in which an output signal of an oxygen amount controller is corrected by a calorie set value correction rate and an inverse ratio, and the difference between the two input signals of the air flow controller is zero.

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