JPH11351504A - Boiler controlling device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve responsiveness of the amount of fuel and the amount of generated steam to a boiler and conduct operation in a stable manner by providing a path for adding a suction pressure control signal of a compressor as a lead signal, in addition to a main steam pressure control system for detecting variation of a main steam pressure and controlling the flow rate of fuel. SOLUTION: A control signal from a controller 13 in a suction pressure control system is inputted to a function generator 21. The function generator 21 calculates a main steam pressure and fuel amount on the basis of a revolution number signal from the controller 13 and a main steam function with the resultant being transmitted to an adder 22. The adder 22 then adds an output signal from a controller 8 to an output signal from the function generator 21. Thus, by providing a path for the function generator 21 and the adder 22, a control signal from a suction pressure of a compressor 3 is added thereto as a lead signal, thereby improving responsiveness of the amount of fuel and the amount of generated steam to a boiler 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for a boiler for supplying steam to a steam turbine for driving a compressor, and more particularly to a compressor connected to a steam turbine driven by main steam of a boiler. The invention relates to a boiler control device having a suction pressure control system for controlling the amount of main steam flowing into a steam turbine by the suction pressure of the boiler and a main steam pressure control system for controlling the amount of fuel to the boiler by the main steam pressure at the boiler outlet .

[0002]

2. Description of the Related Art Conventionally, with respect to a change in load of a compressor driven by a steam turbine, a main steam pressure at a boiler outlet is detected, and a fuel supply to the boiler is performed in response to the change in the main steam pressure. A control method for adjusting the amount is generally performed. FIG. 5 shows an example of a control system diagram of such a conventional steam turbine for driving a compressor and a boiler. In the figure, when high-temperature steam generated in a boiler 01 is supplied to a steam turbine 02 for driving a compressor through a main steam pipe 04, a compressor 03 connected to the steam turbine 02 is supplied.
Is driven to rotate.

Here, when the suction pressure of the compressor 03 fluctuates, the detection value from the suction pressure detector 010 and the setting device 012
Are compared by the deviation calculator 011, and the controller 013 outputs an operation signal to the governor 014 according to the signal from the deviation calculator 011. The governor 014 adjusts the rotation speed of the steam turbine 02.
Sends a valve opening signal (0 to 100%) to the steam control valve 015, adjusts the flow rate of main steam to the steam turbine 02, and controls the rotation speed of the steam turbine 02 to a target value.

On the other hand, when the amount of main steam flowing into the steam turbine 02 fluctuates, a main steam pressure detector 05 detects a change in the main steam pressure at the boiler outlet accompanying the flow rate fluctuation, and the detected value from the detector 05 is detected. And the set value from the setter 07 are compared and calculated by the deviation calculator 06, and the controller 08 sends a valve opening signal (0 to 100%) to the fuel adjustment valve 09 in accordance with the operation signal from the deviation calculator 06. The amount of steam generated in the boiler 01 is adjusted by adjusting the amount of fuel supplied to the boiler 01, and the main steam pressure at the boiler outlet is controlled to a target value.

Next, the operation will be described with reference to the time chart of FIG. 6. As shown in FIG.
When the suction pressure of No. 3 decreases, the rotation speed of the steam turbine 02 is reduced in order to reduce the suction flow rate of the compressor and recover the suction pressure. Therefore, the suction pressure of the compressor 03 is
10, the deviation calculator 011 and the controller 013
The governor 014 that adjusts the rotation speed of the steam turbine 02 in the direction of closing the steam control valve 15 according to the operation signal of.

As a result, as shown in (b), the main steam flow rate at the inlet of the steam bin bin 02 decreases, and a little later, as shown in (c), the boiler outlet main steam pressure increases. At this time, the fluctuation of the main steam pressure at the boiler outlet is detected by the main steam pressure detector 05, and as shown in (d), the fuel is adjusted by the valve opening degree to the fuel adjusting valve 09 in accordance with the operation signal from the deviation calculator 06. When the flow rate is reduced to reduce the amount of steam generated by the boiler, the boiler outlet main steam pressure recovers to the target value as shown in (c).

On the contrary, when the suction pressure of the compressor 03 increases as shown in FIG.
In order to increase the suction flow rate and lower the suction pressure, the rotation speed of the steam turbine 01 is increased. Then, as shown in (b), the flow rate of the main steam at the inlet of the steam turbine increases, and thereafter, as shown in (c), the main steam pressure at the boiler outlet decreases slightly later. At this time, the fluctuation of the main steam pressure at the boiler outlet is detected by the main steam pressure detector 05, and as shown in (d), the fuel flow rate is increased to increase the amount of steam generated in the boiler 01. As shown, the boiler outlet main steam pressure is controlled to recover to the target value.

[0008]

As described above, in the conventional boiler control system, the fluctuation of the suction pressure of the compressor 03 is directly detected, and the fuel flow rate is adjusted so that the boiler outlet main steam pressure recovers to the target value. Instead of adjusting the suction pressure of the compressor 03 → adjusting the rotation speed of the steam turbine 02 → detecting the fluctuation of the main steam pressure at the boiler outlet which appears for the first time after the fluctuation of the main steam flow rate at the inlet of the steam turbine to the boiler 01. However, since the main steam pressure is controlled by adjusting the fuel flow rate, the response to the fluctuation of the suction pressure of the compressor is slow (delayed by α in FIG. 6).

According to the present invention, in addition to a main steam pressure control system for detecting a fluctuation in the main steam pressure and adjusting a fuel flow rate, a load of the compressor is added by adding a suction pressure control signal of the compressor as a preceding signal. It is an object of the present invention to provide a control device that improves responsiveness to fluctuations and can stably operate a boiler.

[0010]

SUMMARY OF THE INVENTION The present invention provides a main steam pressure control system which detects fluctuations in main steam pressure at a boiler outlet and adjusts a fuel flow rate to a boiler, and a control signal from a suction pressure of a compressor. Is added to the main steam pressure control system as an advance signal to improve the responsiveness of the fuel amount and steam generation amount to the boiler.

That is, the present invention provides a suction pressure control system for controlling the amount of main steam flowing into a steam turbine by the suction pressure of a compressor connected to a steam turbine driven by the main steam of a boiler, and a boiler. In a boiler control device having a main steam pressure control system for controlling the amount of fuel to the boiler according to the main steam pressure at the outlet, the main steam pressure is converted into a main steam pressure by a rotation speed signal calculated from an increase or decrease in the suction pressure of the compressor. A function generator is provided, and an operation signal from the function generator is added to the main steam pressure control system as a preceding signal to control the fuel amount to the boiler.

A second aspect of the present invention effectively embodies the first aspect of the present invention, wherein a suction pressure for detecting a suction pressure of a compressor connected to a steam turbine driven by main steam of a boiler is provided. A detector, a deviation calculator for comparing a detection value from the suction pressure detector with a set value, and a controller for outputting an operation signal of a steam turbine speed controller in accordance with an output signal from the deviation calculator A suction pressure control system for controlling the amount of main steam flowing into the steam turbine by the suction pressure, a main steam pressure detector for detecting main steam pressure at the boiler outlet, and a detection from the main steam pressure detector A deviation calculator for comparing and calculating a value and a set value; and a controller for outputting an operation signal of a fuel regulating valve in accordance with a signal from the deviation calculator, and controlling a fuel amount of the boiler by the main steam pressure. Main steam pressure control And a function generator for converting the operation signal from the function generator into a main steam pressure by a rotation speed signal from a controller of a suction pressure control system. An adder is provided to add to the pressure, and the opening degree of the fuel valve is adjusted by the addition operation signal added by the adder to control the main steam pressure.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to an embodiment shown in the drawings. However, unless otherwise specified, dimensions, shapes, relative arrangements, and the like of the components described in this embodiment are not intended to limit the scope of the invention, but are merely illustrative examples.

1 to 4 show a control device for a boiler according to an embodiment of the present invention. FIG. 1 is a system diagram of the control device, FIG. 2 is a functional block diagram thereof, and FIG. FIG. 4 is a time chart showing the effect. FIG. 1 shows an embodiment of the present invention.
This will be described with reference to FIGS. The same members as those in FIG. 5 of the related art are denoted by the same reference numerals except for the leading “0”, and overlapping detailed description will be omitted.

In FIG. 1, reference numeral 1 denotes a boiler for generating steam, a combustion burner 19 into which fuel regulated by a fuel regulating valve 9 is supplied from below, and a superheater 18 above the combustion burner 18 and an evaporator. The evaporator 17 is provided.
Boiler water is supplied through a steam drum 16 and evaporated by an evaporator 17, the boiler steam is superheated by a superheater 18, and the main steam from the boiler 1 is supplied to a main steam pipe 4 and a steam control valve 15. The steam is supplied to the steam turbine 2 for driving the compressor. Reference numeral 3 denotes a compressor connected to and driven by the steam turbine 2.

Reference numeral 5 denotes a main steam pressure detector interposed on the main steam pipe 4 for detecting the main steam pressure, 6 a deviation calculator for comparing the detected value of the main steam pressure with a set value, and 7 a main steam pressure detector. A pressure setter 8 is a controller that outputs an operation signal to the fuel adjustment valve 9 in accordance with a signal from the deviation calculator 6, and 9 is an adder 2
2 is a fuel regulating valve which is operated by a valve degree signal from the fuel injection valve 2. The main steam pressure control system is composed of the main steam pressure detector 5, the deviation calculator 6, the setting unit 7, the controller 8, the fuel regulating valve 9, and the like.

On the other hand, on the suction side of the compressor 3, reference numeral 10 denotes a suction pressure detector of the compressor 3, reference numeral 11 denotes a deviation calculator for comparing the detected suction pressure value with a set value, and reference numeral 12 denotes a setting of the suction pressure of the compressor 3. 13 is a controller for outputting an operation signal to the governor 14 in accordance with a signal from the deviation calculator 11, 14 is a governor for adjusting the rotation speed of the steam turbine 2, and 15 is a governor 1.
4 is a steam control valve operated by a valve degree signal from the control valve 4. The suction pressure detector 10, the deviation calculator 11, the setting unit 12, the controller 13, the governor 14, the steam control valve 15, etc. constitute a suction pressure control system. The configuration up to this point is the same as that of the above-described conventional technology.

The controller 13 of the suction pressure control system
The control signal is also taken into the function generator 21, which calculates the main steam pressure / fuel amount from the rotation speed signal from the controller 13 and the main steam function and sends it to the adder 22. I do. The adder 22 adds the output signal from the controller 8 and the output signal from the function generator 21. In the present invention, a path for the function generator 21 and the adder 22 is provided, and the compressor 3
The gist of the present invention is that the control signal from the suction pressure is added as a preceding signal to improve the responsiveness of the fuel amount and the steam generation amount to the boiler 1.

FIG. 2 shows a functional block diagram of the above, and FIG. 3 shows a control flowchart thereof. The operation of the present embodiment will be described based on these drawings. First, according to the boiler control device configured as shown in FIG. 1 as described above, the boiler water supplied to the steam drum 16 of the boiler 1 passes through the evaporator 17 and the superheater 18 while passing through the combustion burner 19. Heat is exchanged by the combustion gas from the steam generator to generate high-temperature steam. The steam is supplied to the steam turbine 2 for driving the compressor through the main steam pipe 4, so that the compressor 3 connected to the steam turbine 2 is rotationally driven.

Here, in the suction pressure control system, if the suction pressure of the compressor 3 fluctuates due to some disturbance or a pressure change from a process to which the compressor 3 is connected, as shown in FIGS. After the suction pressure of the compressor 3 is detected by the suction pressure detector 10 (S11), the detected value from the suction pressure detector 10 is compared with the set value from the setting unit 12 by the deviation calculator 11 (S12). If there is a deviation between the two values, the deviation calculator 11 calculates an operation signal of the rotation speed according to the deviation (S13), and the deviation calculator 1
The controller 13 outputs an operation signal to the governor 14 in response to the signal from the controller 1.

The governor 14 for adjusting the rotation speed of the steam turbine 2 sends a valve opening signal (0 to 1) to the steam control valve 15.
00%) and controlling the opening (S15).
The main steam inflow into the steam turbine 2 is adjusted (S16),
The rotation speed of the steam turbine 2 is controlled to the target value (S1
7). On the other hand, the operation signal branched from the controller 13 is used to calculate the main steam pressure and fuel amount by the function generator 21 and sent to the adder 22 as a preceding signal (S14).

Simultaneously with the above operation, in the main steam pressure control system, after the main steam pressure detector 5 detects a change in the main steam pressure at the boiler outlet (S1), the detected value from the pressure detector 5 and the setting device 7 are set. Are compared by the deviation calculator 6 (S2). If both values have a deviation, the deviation calculator 6
After calculating the deviation, the controller 8 calculates the operation signal of the fuel regulating valve 9 corresponding to the fuel amount according to the deviation by the deviation signal from the computing unit 6 (S3), and outputs it to the adder 22. A signal is sent.

The adder 22 adds a function generator 21 to an operation signal of the fuel regulating valve 9 corresponding to the fuel amount corresponding to the deviation.
(S4), and sends a valve opening signal (0 to 100%) to the fuel control valve 9 to operate the fuel control valve 9 (S5) to increase or decrease the amount of fuel to the boiler 1. Boiler 1
Is adjusted, and the main steam pressure at the boiler outlet is controlled to the target value (S6).

The effect of the above operation will be described with reference to the timing chart of FIG. 4. When the suction pressure of the compressor 3 decreases in the line A (a), the suction flow of the compressor 3 is reduced to recover the suction pressure. The rotation speed of the steam turbine 2 decreases, and in (b), the main steam flow rate at the steam turbine inlet decreases. Therefore, the reduction signal of the rotation speed is converted into the main steam pressure, and the fuel flow rate is reduced in (d) to reduce the steam generation amount of the boiler. However, since the main steam flow rate at the inlet of the steam turbine has decreased in (b), the main steam pressure at the boiler outlet quickly recovers to the target value as shown in (c).

Conversely, when the compressor suction pressure increases in (a) of line B, the rotational speed of the steam turbine 2 increases to increase the suction flow rate of the compressor and recover the suction pressure, and (b) In), the steam turbine inlet main steam flow increases. Then, the increase signal of the rotation speed is converted into the main steam pressure, and the fuel flow rate is increased in (d) to increase the steam generation amount of the boiler. Although the pressure rises, (c) since the main steam flow rate at the steam turbine inlet is increased in (b).
As shown in the above, the boiler outlet main steam pressure is controlled so as to quickly recover to the target value. In this way, the response delay of the fuel flow rate of (d) is eliminated and the fluctuation of the main steam pressure at the boiler outlet is reduced as shown in (c) of FIG. 4, as compared with the time chart of the prior art of FIG. It is shown that the response is improved.

[0026]

As described above, according to the present invention, in addition to the main steam pressure control system for detecting the fluctuation of the main steam pressure and adjusting the fuel flow rate, a control signal from the suction pressure of the compressor is added as a preceding signal. Therefore, the fuel flow rate can be quickly adjusted before the main steam pressure fluctuates with respect to the suction pressure fluctuation (load fluctuation) of the compressor, and the fluctuation of the main steam pressure can be reduced.

Further, as the adjustment of the fuel flow rate is performed in advance, the response of the steam generation amount of the boiler becomes faster, and there is an effect that the pressure fluctuation of the boiler outlet main steam pressure can be suppressed. Therefore, the boiler can be operated stably with respect to the suction pressure fluctuation of the compressor.

[Brief description of the drawings]

FIG. 1 is a system diagram showing a boiler control device according to an embodiment of the present invention.

FIG. 2 is a functional block diagram of the control device of FIG.

FIG. 3 is a flowchart illustrating a control operation of the control device in FIG. 1;

FIG. 4 is a time chart illustrating various pressure / flow rate changes of the control device of FIG. 1;

FIG. 5 is a system diagram showing a control device for a boiler according to the related art.

6 is a time chart showing various pressure / flow rate changes of the control device of FIG. 5;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Boiler 2 Steam turbine 3 Compressor 4 Main steam pipe 5 Main steam pressure detector 6, 11 Deviation calculator 7, 12 Setting device 8, 13 Controller 9 Fuel adjustment valve 10 Suction pressure detector 14 Governor 15 Steam control valve 21 Function generator 22 Adder

Claims (2)

[Claims] 1. A suction pressure control system for controlling an amount of main steam flowing into a steam turbine by a suction pressure of a compressor connected to a steam turbine driven by a main steam of a boiler, and a boiler by a main steam pressure at a boiler outlet. A boiler control device comprising a main steam pressure control system for controlling the amount of fuel to the boiler, a function generator for converting the main steam pressure into a main steam pressure by a rotation speed signal calculated from an increase or a decrease in the suction pressure of the compressor, A control device for a boiler, wherein an operation signal from the function generator is added as a preceding signal to a main steam pressure control system to control a fuel amount to the boiler. 2. A suction pressure detector for detecting a suction pressure of a compressor connected to a steam turbine driven by main steam of a boiler, and a detection value from the suction pressure detector is compared with a set value. Suction pressure control, comprising: a deviation calculator; and a controller for outputting an operation signal of a steam turbine speed controller in accordance with an output signal from the deviation calculator, and controlling an amount of main steam flowing into the steam turbine by a suction pressure. System, a main steam pressure detector for detecting a main steam pressure at the boiler outlet, a deviation calculator for comparing a detection value from the main steam pressure detector with a set value, and a signal from the deviation calculator. A controller that outputs an operation signal of the fuel adjustment valve according to the
A boiler control device comprising a main steam pressure control system for controlling a fuel amount of the boiler by the main steam pressure, wherein a function generator for converting into a main steam pressure by a rotation speed signal from a controller of the suction pressure control system; An adder for adding the operation signal from the function generator to the operation signal of the main steam pressure control system, and adjusting the opening of the fuel valve by the addition operation signal added by the adder; A boiler control device characterized by controlling the following.