JPH025703A - Boiler/turbine cooperated control device - Google Patents

Abstract

PURPOSE:To make it possible to variably control main steam pressure smoothly and stably by previously adding CV opening signal as a bias signal to a flow control signal for controlling fuel and air quantity supplied to a boiler. CONSTITUTION:MSP deviation signal 29 receives CV opening command signal 23 before CV control unit 9 and it is previously added in an adder 24 as a bias signal 26. Thus, larger deviation volume is added to MSP deviation signal 29 so that it becomes possible to previously detect the change of excessive increase and decrease of MSP corresponding earlier to increase and decrease of CV opening by CV control unit 9. Accordingly, excessive change of MSP can be prevented so that stable changing pressure operation and constant operation can be usually continued.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention relates to a boiler-turbine cooperative control device used in a power generation plant etc. equipped with a boiler-turbine, and in particular,
The present invention relates to a boiler-turbine cooperative control system that allows smooth changes in the pressure of main steam that drives a turbine and stably controls the operation of a plant.

(Prior Art) Steam drive devices equipped with a boiler and a turbine are used in a wide range of fields in combination with water production plants and the like in addition to power plants.

FIG. 2 is a system diagram showing an example of the configuration of a private power generation water desalination plant that combines a steam drive device and a desalination plant. This private power generation desalination plant includes a boiler 1 that generates steam for driving a turbine, a turbine 2 that is driven by the steam supplied from the boiler 1, a power generation n3 that is directly connected to the turbine 2, and a power generation unit that supplies steam to the turbine 2. A regulating valve (hereinafter referred to as Cv) 4 that adjusts the main steam flow rate, a water production plant 5 that produces water using the steam discharged from the turbine 2 as a heat source,
Detects the condenser 6 that condenses steam discharged from the water production plant 5, the boiler feed pump (hereinafter referred to as rBFPJ) 7 that supplies condensed water to the boiler 1 again, and the main steam pressure (hereinafter referred to as rMsPJ). A regulating valve control device (hereinafter referred to as "MSP detector") which adjusts the valve opening of CV4 based on a detection signal from a main steam pressure detector (hereinafter referred to as "MSP detector") 8.
Hereinafter referred to as "CV control device". ) 9 and MSP detector 8
The boiler control device 'a12 controls the fuel adjustment device 10 and the air adjustment device V111 based on detection signals from the boiler control device V111.

Next, the operation of the private power generation water desalination plant having the above configuration will be explained. The steam generated in the boiler 1 is fed to the turbine 2 via CV4, and a part of the thermal energy and pressure energy (proportional to enthalpy i) of the main steam is converted into rotational energy of the turbine 2, and further Directly connected generator 3
is converted into electrical energy by The steam that has done work in the turbine 2 is sent to a downstream water production plant 5, where a certain heat source Q is applied as a heat source for water production, and then it is condensed by a condenser 6. The condensed water is pressurized via the boiler feed water pump 7 and sent to the boiler 1.
is refluxed to. The condensed water that has returned to boiler 1 is
It is heated by the combustion device 13 inside and becomes steam for driving the turbine again.

By the way, in a private power generation and desalination plant that combines a steam drive device and a desalination plant as described above, the output of the generator 3 fluctuates significantly because the heat loss within the plant system generally differs between daytime and nighttime.

On the other hand, in order to ensure operational stability, it is necessary to always supply a constant amount of heat IQ to the water production plant 5.

In order to satisfy the above conditions and operate the entire plant in a stable condition without reducing power generation efficiency,
The enthalpy i input to the turbine 2 is increased or decreased by an amount equivalent to the change in the output of the generator 3, and the steam flow mF fed to the turbine 2 is changed to give a constant thermal slippage Q to the water production plant 5.
Operation control is required to maintain a constant value.

Therefore, the enthalpy i of the steam input to the turbine 2
In order to change the main steam pressure (MSP), it is necessary to adjust the valve opening of CV4 in response to the change in main steam pressure (MSP).

That is, when performing the above-mentioned variable pressure operation, the main steam pressure (MSP) is detected by the MSP detector 8, and the obtained MSP detection signals 14a and 14b are transmitted to the CV control device 9 and the boiler control device 12, respectively. do. The CV control device 9 calculates the MSP detection signal 14a, and when it is lower than a predetermined value, closes the CV 4, and when it is higher than the predetermined value, closes the CV 4, so that the steam flow aF and enthalpy i supplied to the turbine 2 are set to a predetermined value. Control to value.

On the other hand, the boiler control device 12 receives the MSP detection signal 14b and sends a fuel adjustment command signal 1 so that the MSP value becomes a predetermined value.
5 and an air amount adjustment command signal 16. In response to the command signals 15 and 16, the fuel adjustment device 10 and the air amount adjustment device 11 adjust the amount of fuel and air supplied to the combustion device 13, and finally control the combustion heat generation in the boiler 1.

Next, CV4 adjusts the main steam flow rate supplied to the turbine 2.
An example of the configuration and operation of the C2 control device 9 that controls the valve opening degree will be described with reference to FIG.

The Cv control device 9 controls the Cv control device in response to the MSP detection signal 14a.
It has a function calculator 18 that outputs a V opening degree setting signal 17. As shown in FIG. 4, this function calculator 18 calculates the C2 opening degree setting value corresponding to the MSP detection value according to the characteristic curve f(x). The deviation between the Cv opening setting signal 17 outputted from the function calculator 18 and the Cv actual opening detection signal 19 from the regulating valve (CV) 4 is calculated by the calculator 20.
Arithmetic unit 20 +, t Outputs CV opening deviation signal 21.

The CV opening degree deviation signal 21 is input to the CV opening degree control device 22, and the CV degree control device 22 gives the CV opening degree command signal 23 to the CV4 to eliminate the deviation in the CV degree of opening, and controls the valve opening degree. Control.

(Problems to be Solved by the Invention) However, according to the conventional Cv control device 9, when performing so-called variable pressure operation in which the pressure of main steam supplied to the turbine is changed as shown in FIG. The MSP value is decreased from α and the operating point is moved to the β point. At this time, the C■ opening degree setting value should move from B to B'. However, the regulating valve (CV) by the CV opening setting signal 17
An increase in the opening degree of No. 4 leads to an increase in the outflow of main steam flowing into the turbine 2, leading to a sharp decrease in MSP.

As a result, MSP decreases further than the expected MSPltlA', and the operating point shifts to γ.

As described above, when the conventional C① control device 9 attempts to increase or decrease the MSP value, it operates in the direction of increasing or decreasing the Cv opening according to the regulating valve opening setting signal 17. For example, if the opening degree of C is increased in order to reduce MSP, an increase in main steam outflow flowing into the turbine 2 is induced, which further reduces MSP. This reduction in MSP further promotes an increase in the Cv opening degree, which has the drawback of acting in the direction of amplifying the change, which further induces a decrease in MSP.

Therefore, a large disturbance may be given to the boiler control device 12 that controls the heat generation M of the boiler 1 based on the MSP detection value. This disturbance is sometimes M S P 1fl
This may lead to a hunting phenomenon in which the plant cannot continue to operate stably.

The present invention has been made to solve the above problems, and is a boiler-turbine cooperative control device that enables smoother and more stable variable control of main steam pressure during variable pressure operation of main steam. The purpose is to provide

[Structure of the invention]

(Means for Solving the Problems) A boiler-turbine cooperative control device according to the present invention uses a main steam pressure signal xi to adjust a regulating valve opening degree to a regulating valve that regulates a main steam flow m to be fed to a turbine. A regulating valve control device that outputs a signal, a boiler control device that calculates a main steam pressure signal and outputs a flow rate control signal for fuel and steam supplied to the boiler, and controls the flow rate using the regulating valve opening signal as a bias signal. It is characterized by comprising an adder that adds to the signal.

(Function) CV as before! Unlike the system in which the II @ device and the boiler control device are operated individually in parallel to control the Cv and the boiler respectively, the boiler-turbine cooperative control device with the above configuration allows the control device to control the CV interval signal. is sent to the boiler control device in advance, and this Cv opening signal is added as a bias signal to the flow rate control signal that controls the amount of fuel and air supplied to the boiler to control the operation of the boiler.

Therefore, it is possible to control the increase/decrease change in MSP temperature corresponding to the increase/decrease in CV opening by the Cv control device more quickly, making it possible to prevent excessive fluctuations in MSP, and stably operating the plant. Can be continued.

(Example) Next, an example of the present invention will be described with reference to the accompanying drawings.

FIG. 1 is a system diagram showing an embodiment of a boiler-turbine cooperative control device according to the present invention. Note that the same elements as those in the conventional example shown in FIGS. 2 and 3 are designated by the same reference numerals, and detailed explanation thereof will be omitted.

The boiler-turbine cooperative control device according to this embodiment has a first
As shown in the figure, a regulating valve control device 9 that calculates a main steam pressure signal 14a and outputs a regulating valve opening command signal 23 to a regulating valve 4 that adjusts the main steam flow rate fed to the turbine 2; A boiler control device 12a that calculates a steam pressure signal 14b and outputs a flow rate control signal for fuel and steam to be supplied to the boiler 1, and an adder that adds the regulating valve opening command signal 23 as a bias signal to the flow rate control signal. 24.

Here, the regulating valve control device 9 has the same configuration as the conventional example shown in FIG. It is a point.

The boiler control device 12a calculates the C■ opening command signal 23 and outputs the bias signal 26 using the Cv opening signal calculation B2.
5, the bias signal 26, and the MS from the MSP setter 27.
An adder 24 that adds the P setting signal 28 and the MSP detection signal 14b from the MSP detector 8 and outputs an MSPit difference signal 29, and an adder 24 that calculates the fuel flow value necessary to eliminate the MSP deviation and outputs the fuel setting signal. The deviation processing unit σ device 31 which outputs 30 compares the fuel flow detection signal @33 from the fuel flow rate detector 32 with the fuel setting signal 30 and generates a fuel deviation signal @34.
In response to the comparator 35 outputting , and the fuel deviation signal 34,
The fuel control device 36 outputs a fuel adjustment command signal 15 that controls the fuel adjustment device 10.

The boiler control device 12a also includes an air flow rate detector 37 as a control device that adjusts the amount of air corresponding to changes in the fuel flow rate.
The air flow rate setting signal 41 is obtained by multiplying the air flow rate detection signal 38 from the air-fuel ratio setter 39 by the air-fuel ratio setting signal 40 from the air-fuel ratio setting device 39.
A multiplier 42 that outputs the MSPG difference signal 29 and a deviation processing calculator 44 that outputs the air amount command signal 43, compares the air flow rate setting signal 41 and the air amount command signal 43, and generates an air amount deviation signal. and an air amount control device 47 which receives the air amount deviation signal 45 and outputs an air ffi adjustment command signal 16 that drives the air amount adjustment device 11.
and has.

That is, the boiler control device 12a of the boiler-turbine cooperative control device according to this embodiment has almost the same configuration as the conventional boiler control device 12 shown in FIG. The difference is that the vessel is powered by 24 people.

In the conventional boiler control device 12, an adder adds the MSP detection signal 14b and the MSP setting signal 28 in response to changes in MSP, and outputs the deviation as an MSP deviation signal.
Thereafter, the fuel flow rate is adjusted through the deviation processing 8II calculator 31 and the fuel control device 36, while the MSP deviation signal is processed by the deviation processing calculator 44 and the air amount control device 47.
The air flow rate was regulated by the output air flow control command signal 16.

Therefore, when performing variable voltage operation, the CV control device 9
The MSP control loop starts to operate only when the MSP value actually changes significantly due to the change in the CV opening due to the operation of , and the MSP deviation signal fluctuates greatly. Therefore, unless the control gain of each control circuit of the boiler control bag @12 was set large, it was impossible to prevent a large variation in MSP.

However, in this embodiment, the MSP deviation signal 29 receives the CV opening command signal 23 from the C control device 9 in advance, and adds the CV opening command signal 23 in advance in the adder 24 as a bias signal 26 based on the CV opening. MS
This is incorporated into the P deviation signal 29 as a larger deviation amount. Therefore, it becomes possible to detect in advance an excessive increase or decrease in MSP corresponding to an increase or decrease in the Cv degree by the CV control device 9, and it is possible to prevent excessive fluctuations in MSP. Therefore, stable variable pressure operation and constant pressure operation can be maintained at all times.

Further, in this embodiment, the CV opening degree 1d order signal 23 is used as a signal transmitted from the CVII control device 9 to the boiler control device 12a, but the signal is not limited to this signal. For example, if the signal is related to the CV opening degree, such as the Cv opening degree setting signal @17, the Cvv degree deviation signal 21, or the C■ actual degree detection signal 19, the Cvv degree command signal 23 can be changed by performing appropriate signal processing. The same effects can be obtained.

〔Effect of the invention〕

As explained above, according to the boiler-turbine cooperative control device according to the present invention, the Cvv degree signal of the CV control device is sent to the boiler control device in advance, and this Cv intermittent signal is used to control the amount of fuel and air supplied to the boiler. The control signal is added in advance as a bias signal to control the operation of the boiler. Therefore, CvfiIIIi! It becomes possible to control the increase/decrease change in MSP corresponding to the increase/decrease in CV opening by the ll device more quickly, making it possible to prevent excessive fluctuations in MSP, and allowing stable plant operation to continue. .

[Brief explanation of the drawing]

Fig. 1 is a system diagram showing an embodiment of the present invention, Fig. 2 is a system diagram showing an example of the configuration of a conventional private power generation desalination plant, and Fig. 3 is a system diagram showing an example of the configuration of a conventional regulating valve control device. The block diagram, FIG. 4, is a graph showing an example of a characteristic curve of a function calculator built into the regulating valve control device. 1...boiler, 2...turbine, 3...fire? ! f
Machine, 4... Regulating valve (CV), 5... Water production plant,
6... Capacitor, 7... Boiler feed pump, 8...
...Main steam pressure detector (MSP detector), 9...Adjustment valve control device (CVfllllllfili, 10)
...Fuel adjustment device, 11 ...Air amount adjustment device, 1
2.12a... Boiler control device, 73... Combustion device, 14a, 14b... MSP detection signal, 15... Fuel adjustment command signal, 16... Air amount adjustment command signal, 17
...Cv opening setting signal, 18...Function calculator, 19
... C ■ Actual degree detection signal, 20 ... Arithmetic unit, 21.
・・C■Opening degree deviation signal, 22...Cv opening degree control device,
23...CV opening command signal, 24...Adder, 25
...CV degree signal emulator, 26...bias signal,
27...MSP setting device, 28...MSP stage setting signal,
29...MSP@difference signal, 30...fuel setting signal,
31... (deviation processing calculator, 32... fuel flow rate detector, 33... fuel flow rate detection signal, 34... fuel (a
Difference signal, 35... Comparator, 36... Fuel control device,
37... Air flow rate detector, 38... Air flow rate detection signal, three... Air-fuel ratio setter, 40... Air-fuel ratio setting signal, 41... Air flow rate setting signal, 42... riding equipment,
43... Air amount command signal, 44... Deviation processing calculator, 45... Air amount deviation signal, 46... Comparator, 47
...Air opening control device. Figure MSP horizontal value

Claims (1)

[Claims] A regulating valve control device that calculates a main steam pressure signal and outputs a regulating valve opening signal to a regulating valve that adjusts the flow rate of main steam sent to the turbine, and a regulating valve control device that computes a main steam pressure signal and supplies it to the boiler. A boiler-turbine cooperative control device comprising: a boiler control device that outputs fuel and steam flow rate control signals; and an adder that adds the regulating valve opening signal as a bias signal to the flow rate control signal.