JP2000121001A - Deaerator water level controller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To constantly keep the water level of a deaerator stably at a desirable water level even when the water level fluctuates excessively to a high level side, and lower the temperature of condensate to the deaerator to a desirable temperature even when temperature of the condensate at an outlet of a gas feed water heater. SOLUTION: A condensate temperature regulating valve control circuit 35 is provided with a control loop 16, a control loop 37 and a low value selector circuit 38. Among condensate demand signals from the control circuits 16, 37, a low value is selected and outputted as a valve travel command to a gas feed water heater outlet condensate temperature regulating valve 8. A condensate relief regulating valve control circuit 36 is provided with a control loop 39, a control loop 40 and a high value selector circuit 41. Among condensate relief flow rate demand signals from the loops 39, 40, a high value is selected and outputted as a valve travel signal to a condensate water relief regulating valve 11.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a deaerator water level control device for a combined cycle power plant, and more particularly to a deaerator water level control at a high water level of a deaerator or at a high condensing temperature at a gas feed water heater outlet. The present invention relates to a deaerator water level control device suitable for maintaining stable control.

[0002]

2. Description of the Related Art A combined cycle is a power generation system in which different prime movers are combined to increase the thermal efficiency as compared with a single prime mover. In this combined cycle power plant, there is a power generation system called an exhaust reburn cycle in which exhaust gas from a gas turbine is guided to a boiler with a burner and used as combustion air. The temperature of the exhaust gas generated by the boiler in this manner is high, and the exhaust gas is used to heat the condensate and the feed water of the steam cycle to improve the thermal efficiency of the plant. That is, in a combined cycle power plant of the exhaust gas recirculation cycle type, a gas feedwater heater is incorporated in a condensing system and a feedwater system together with a feedwater heater inherent in a steam cycle for heat recovery of exhaust gas.

In a condensing system having a feed water heater and a gas feed water heater, it is necessary to maintain a proper amount of condensate to the deaerator in each system to stably maintain the water level. In other words, careful consideration is required for the distribution of condensed water between the systems. This distribution is realized by calculating the heat balance in the specified load zone and cooperatively controlling the amount of condensate using the deaerator water level control valve, gas feed water heater outlet condensate temperature control valve, and condensate release control valve respectively. are doing.

More specifically, as shown in FIG. 6, the condensate is heated by steam from a bleed air system (not shown) while passing through a low-pressure feed water heater 2 of a first condensate pipe 1 and degassed. It flows into the vessel 3. Separately, the condensate is supplied to the second condensate pipe 4
Is heated by the exhaust gas flowing through the exhaust gas system 6 while passing through the gas feed water heater 5, and flows into the deaerator 3. First
A deaerator water level control valve 7 and a gas supply water heater outlet condensate temperature control valve 8 are provided in the second condenser pipes 1 and 4.

[0005] Further, a condensate discharge pipe 10 for communicating the first and second condensate pipes 1 and 4 with the condenser 9 is provided.
A condensate release control valve 11 is interposed in this path.
During operation of the plant, a control signal is given from the deaerator water level control device 12 to the water level control valve 7, the gas feed water heater outlet temperature control valve 8, and the condensate release control valve 11, and the opening degree changes. Thus, the amount of water condensed to the deaerator 3 is adjusted.

FIGS. 7 and 8 show a deaerator water level controller 12.
The details are shown. FIG. 7 shows the control means used at the stage when the specified load is reached from the start. The deaerator water level control valve 7 is controlled by the control loop 14 of the deaerator water level control valve control circuit 13 based on the load signal a based on the load signal a. It is controlled to keep the opening. In addition, the deaerator water level is set to the standard water level (NW.
L) In order to keep the gas feed water heater outlet condensate temperature control valve 8
Is controlled by the control loop 16 of the condensate temperature control valve control circuit 15 so that the deviation between the deaerator water level signal b and the set value based on the standard water level is made zero.

Further, the condensate release control valve 11 is controlled by a control loop 18 of the condensate release control valve control circuit 17 to maintain the condensate temperature at the gas feed water heater outlet at a desired temperature. And a deviation from a set value based on a temperature lower by a certain value (β) than the deaerator water tank temperature signal d is controlled to be zero. As a result, the deaerator water level can be operated with a stable water level until it rises to the specified load without greatly changing. In the drawing, reference numeral 19 denotes a function generator for setting the lower limit opening, and reference numeral 20 denotes a high value selection circuit.

On the other hand, FIG. 8 shows control means used at a stage after the load reaches the specified load. In order to keep the deaerator water level at the standard level, the deaerator water level control 7 includes a water level control valve control circuit 13.
Is controlled so that the deviation between the deaerator water level signal b and the set value based on the standard water level is made zero. The gas feed water heater outlet condensing temperature signal c is controlled by the control loop 21 of the condensing water temperature control valve control circuit 15 to maintain the gas feed water heater outlet condensing temperature at a desired temperature. And the deaerator water tank temperature signal d
Is controlled so that a deviation from a set value based on a temperature lower by a certain value (ε) than the reference value is zero.

Further, the condensate temperature control valve control circuit 15 controls the control loop 22 when the deaerator water level is lower than the standard water level.
Outputs a command to keep the water level higher than the standard water level by a certain value (μ). At this time, condensate is additionally supplied to the condensate system.

The condensate release control valve 11 is controlled by the control loop 23 of the condensate release control valve control circuit 17 to maintain the condensate temperature at the gas feed water heater outlet at a desired temperature. And the deaerator water tank temperature signal d
Is controlled so that a deviation from a set value based on a temperature lower by a certain value (λ) than the reference value is zero. Note that the relationship between ε and λ is ε> λ. In the drawing, reference numeral 24 indicates a high value selection circuit.

[0011]

However, in actual plant operation, the heat balance under a specified load is not always constant depending on the operating conditions. Therefore, the amount of condensate flowing into the deaerator 3 does not become the calculated flow rate, and as a result, the deaerator water level control falls into an unstable state.

Further, the exhaust gas which heats the condensate flowing in the gas feed water heater 5 has a low temperature and is discharged into the atmosphere from the chimney. When provided at the inlet of the gas feed water heater 5,
If the deaerator water level control is performed by the gas feed water heater outlet condensate temperature control valve 8 until the specified load is reached, the return to the deaerator 3 is performed when the deaerator water level becomes higher than the set value described above. Water is not required. For this reason, the condensed water does not flow into the gas feed water heater 5, and at this time, the cooling of the exhaust gas does not proceed, so that there is a possibility that the high-temperature exhaust gas cannot be discharged into the atmosphere from the chimney as it is.

Accordingly, an object of the present invention is to keep the deaerator water level at a standard level constantly and stably even when the deaerator water level fluctuates to an excessively high water level. An object of the present invention is to provide a deaerator water level control device capable of reducing the condensate temperature to the deaerator to a desired temperature even when the temperature becomes high.

[0014]

According to a first aspect of the present invention, there is provided a condensate temperature control valve control circuit, wherein a condensate temperature difference between a detected deaerator water level signal and a predetermined set value is determined. A first control loop for outputting a condensate flow rate request signal in response to a condensate flow rate request signal, and outputting a condensate flow rate request signal in accordance with a deviation between a detected gas supply water heating outlet condensate temperature signal and a predetermined set value. A second control loop, having a low value selection circuit for outputting any one of these condensate flow rate request signals as a command for determining an opening degree of the condensate temperature control valve at the gas feed water heater outlet; A relief control valve control circuit configured to output a condensate relief flow rate request signal in accordance with a deviation between the detected deaerator water level signal and a predetermined set value;
A fourth control loop for outputting a condensate escape flow rate request signal in accordance with a deviation between the detected condensate outlet temperature signal of the gas feed water heater and a predetermined set value; A first high value selection circuit is provided which outputs one of them as a command for determining the degree of opening of the condensate release control valve.

In the deaerator water level control device having the above configuration, even if the deaerator water level fluctuates excessively high until the plant reaches the specified load, the opening of the condensate relief control valve is controlled. By adjusting, it is possible to always maintain the deaerator water level stably at the standard water level.

Further, even when the condensate temperature at the outlet of the gas feed water heater becomes high, the condensate temperature flowing into the deaerator can be lowered to a desired temperature by adjusting the opening of the condensate release control valve.

According to a second aspect of the present invention, the condensate temperature control valve control circuit outputs a condensate flow rate request signal in accordance with a deviation between the detected deaerator water level signal and a predetermined set value. A fifth control loop, a sixth control loop for outputting a condensate flow rate request signal in accordance with a deviation between a detected condensate temperature signal at the gas feed water heater outlet and a predetermined set value, A second high value selection circuit for outputting one of the flow rate request signals as a command for determining the opening degree of the gas condensate heater outlet condensate temperature control valve, and the condensate release control valve control circuit is detected A seventh control loop for outputting a condensate release flow rate request signal according to a deviation between the deaerator water level signal and a predetermined set value, a detected gas feed water heater outlet condensate temperature signal, Depending on the deviation from the set value. Eighth control loop for outputting a signal,
A third high value selection circuit is provided which outputs any one of the condensate release flow rate request signals as a command for determining the opening degree of the condensate release control valve.

In the deaerator water level control device having the above configuration, the opening of the condensate relief control valve can be controlled even when the deaerator water level fluctuates to an excessively high water level while the plant is operating at a specified load. By adjusting the, the deaerator water level can always be stably maintained at the standard water level.

Further, according to a third aspect of the present invention, a condensate release flow rate request signal is output according to a deviation between a deaerator water level signal detected by a condensate release control valve control circuit and a predetermined set value. A third control loop for outputting a condensate release flow rate request signal in accordance with a deviation between a detected gas feed water heater outlet condensate temperature signal and a predetermined set value; A first high value selection circuit that outputs one of the condensate release flow rate request signals as a command for determining the degree of opening of the condensate release control valve, a detected deaerator water level signal, and a predetermined set value A seventh control loop for outputting a condensate release flow rate request signal in accordance with the deviation from the above, and a condensate release according to a deviation between the detected condensate temperature signal at the gas feed water heater outlet and a predetermined set value. Eighth control for outputting flow rate request signal And a third high value selection circuit that outputs one of these condensate release flow rate request signals as a command to determine the degree of opening of the condensate release control valve, to the condensate release control valve according to the load signal Means for switching and outputting one of the opening degree commands, and outputting a condensate release flow rate request signal according to a deviation between a detected gas feed water heater outlet exhaust gas temperature signal and a predetermined set value. Ninth control loop, the opening degree command to the condensate relief valve based on the condensate release flow request signal from the ninth control loop, and the return based on the condensate release flow request signal from the third, fourth, seventh, and eighth control loops. A fourth high value selection circuit that outputs one of the opening degree commands to the water relief valve is provided.

In the deaerator water level control device having the above configuration, the gas feed water heater can be operated while maintaining a predetermined condensate flow rate under a predetermined gas feed water heater outlet exhaust gas temperature. This makes it possible to stably maintain the deaerator water level at the standard water level while maintaining good thermal efficiency of the plant. Further, the exhaust gas temperature can be reduced to a temperature at which the exhaust gas can be released into the atmosphere.

[0021]

Embodiments of the present invention will be described below with reference to the drawings. In FIG. 3, a deaerator water level control device 31 includes a water level detector 32 and a temperature detector 33 in a water tank of the deaerator 3, and detects a deaerator water level signal b and a deaerator water tank temperature signal, respectively. d is input to a control loop described later. In addition, gas feed water heater 5
Is provided with a temperature detector 34 for detecting a condensate temperature, and a condensate temperature signal c at the outlet of the gas feed water heater is input to a control loop described later.

FIGS. 1 and 2 show a deaerator water level control device 31.
The details are shown. In FIG. 1, the deaerator water level control device 31 includes a deaerator water level control valve control circuit 13, a condensate temperature control valve control circuit 35, and a condensate release control valve control circuit 36.
It has. The deaerator water level control valve control circuit 13 is the same as that according to the prior art.

The condensate temperature control valve control circuit 35 outputs a condensate flow rate request signal corresponding to a deviation between the detected deaerator water level signal b and a set value based on the standard water level.
6 and detected gas feed water heater outlet condensate temperature signal c
And a control loop 37 for outputting a condensate flow rate request signal according to a deviation from a set value based on a temperature lower by a certain value (β) than the deaerator water tank temperature signal d. Also,
A low value selection circuit 38 for selecting a low value from the condensate flow rate request signal and outputting an opening command to the gas feed water heater outlet condensate temperature control valve 8 is provided.

Further, the condensate release control valve control circuit 36 provides a decondenser corresponding to a deviation between the detected deaerator water level signal b and a set value based on a water level higher by a certain value (γ) than the standard water level. Control loop 39 that outputs a water release flow request signal
And the condensate release flow rate according to the deviation between the detected gas feed water heating outlet condensate temperature signal c and a set value based on a temperature lower by a certain value (α) than the deaerator water tank temperature signal d. And a control loop 40 for outputting a request signal. Further, a high value selection circuit 41 for selecting a high value from the condensate release flow rate request signal and outputting an opening command to the condensate release control valve 11 is provided.

On the other hand, in FIG. 2, the deaerator water level control device 31 includes a deaerator water level control valve control circuit 13, a condensate temperature control valve control circuit 15, and a condensate release control valve control circuit 42. The deaerator water level control valve control circuit 13 and the condensate temperature control valve control circuit 15 are the same as those according to the prior art.

The condensate release control valve control circuit 42 performs condensate release according to a deviation between the detected deaerator water level signal b and a set value based on a water level higher by a certain value (σ) than the standard water level. A control loop 13 for outputting a flow rate request signal, a detected gas feed water heater outlet condensate temperature signal c, and a set value based on a temperature lower by a certain value (λ) than the deaerator tank temperature signal d. And a control loop 23 for outputting a condensate release flow rate request signal according to the deviation from the control loop 23. Further, a high value selection circuit 44 for selecting a high value from the condensate release amount request signal and outputting an opening command to the condensate release control valve 11 is provided.

In the present embodiment, the deaerator water level is low during the rise from the start-up of the plant to the specified load, and the deaerator water level signal b from the water level detector 32 and the standard water level are compared. A condensate flow rate request signal that keeps the opening larger due to a deviation from the reference set value is output from the control loop 16 to the gas feed water heater outlet condensate temperature control valve 8 via the low value selection circuit 38. As a result, the condensate temperature control valve 8 at the outlet of the gas feed water heater opens, and the condensate flows into the deaerator 3. When the inflow of condensate continues thereafter, the deaerator water level gradually rises, approaches the deviation between the deaerator water level signal b and the set value, and the deaerator water level settles to the standard water level.

On the other hand, when the deaerator water level becomes higher than the standard water level for some reason, the deaerator water level signal b is supplied from the water level detector 32 to the control loop 39. At this time, a condensate release flow demand signal for keeping the opening larger is output to the condensate release control valve 11 via the high value selection circuit 41, whereby the condensate release control valve 11 is opened and the deaerator 3
Part of the condensate flowing to the condenser 9 passes through the condensate discharge pipe 10
As a result, the deaerator water level stops rising due to a decrease in the inflow condensate. Thus, the deaerator water level can be stably maintained at the standard water level until the specified load is reached.

Further, while the load is raised to the prescribed load, the condensate temperature at the outlet of the gas feed water heater is maintained at a desired temperature by the condensate temperature control valve control circuit 35 and the condensate release control valve control circuit 36. When a certain time has elapsed since the start of the plant, the temperature of the exhaust gas passing through the gas feed water heater 5 becomes high. When the heating by the high-temperature exhaust gas continues, the temperature of the condensate flowing to the outlet of the gas feedwater heater 5 increases, and the temperature detector 34 sends a gas feedwater outlet condensate temperature signal c to the control loop 40.

At this time, the deviation between the condensate temperature signal c and a set value based on a temperature lower by α than the deaerator water tank temperature d becomes large, and the condensate release flow rate demand for keeping the opening larger. A signal is output from the control loop 40 to the condensate relief control valve 11 via the high value selection circuit 41. Thereby, the condensate release control valve 11 is opened, and a part of the condensate flowing toward the deaerator 3 flows out to the condenser 9 through the condensate discharge pipe 10. Thus, a certain amount of condensate is continuously returned to the condenser 9, so that the amount of high-temperature condensate flowing into the deaerator 3 is reduced. As a result, the condensate temperature becomes unfavorable in terms of heat balance. It is possible to avoid rising.

If the rise in the condensate temperature at the outlet of the gas feedwater heater cannot be suppressed, an opening command from the control loop 37 is output to the condensate temperature control valve 8 at the outlet of the gas feedwater heater, and the condensate temperature is controlled. The opening degree of the control valve 8 is further increased. For this reason, the condensate flow rate increases, the condensate temperature flowing to the outlet of the gas feed water heater 5 gradually decreases, and the condensate temperature flowing into the deaerator 3 decreases to an appropriate temperature on the heat balance.

Thus, while maintaining the deaerator water level at the standard water level until the plant reaches the specified load, during this time, when the condensing temperature at the gas feed water heater outlet becomes high,
Condensate to the deaerator 3 can be reduced to a desired temperature.

On the other hand, after reaching the specified load, in the deaerator water level control, an opening command from the control loop 14 is given to the deaerator water level control valve 7, and the deaerator water level is maintained at the standard water level. . The control of the condensate temperature at the outlet of the gas feed water heater is performed by the control loop
Opening degree command from gas feed water heater outlet condensate temperature control valve 8
And the condensate temperature is maintained at the desired temperature.

During this control, if the deaerator water level greatly exceeds the standard water level for some reason, the detected deaerator water level signal b is supplied to the control loop 43. A control loop 43 in which a set value is a value higher than the standard water level by σ.
The deaerator water level signal b is compared with a set value, and when the deaerator water level signal b exceeds the set value, a condensate release flow request signal corresponding to the deviation is condensed and released via the high value selection circuit 44. Output to the control valve 11. As a result, the condensate release control valve 11 opens and a part of the condensate flowing toward the deaerator 3 flows out to the condenser 9 through the condensate discharge pipe 10. As a result, the amount of condensate flowing into the deaerator 3 decreases, and the rise in the deaerator water level stops.

Thus, even when the deaerator water level rises excessively during operation at the specified load, the deaerator water level is stably maintained at the standard water level by maintaining the opening of the condensate release control valve 11 corresponding to the water level fluctuation. Can be held.

As described above, according to the present embodiment, even when the deaerator water level fluctuates to an excessively high water level, the opening of the condensate release control valve 11 is adjusted to match the change.
The deaerator water level can always be stably maintained at the standard water level. Also, when the condensate temperature at the outlet of the gas feed water heater becomes high, it is possible to lower the condensate temperature to the deaerator to a desired temperature by adjusting the degree of opening of the condensate release control valve 11 so as to match it. Will be possible.

Next, another embodiment of the present invention will be described. In FIG. 4, a temperature detector 45 is provided in an exhaust gas system 6 connected to a gas feed water heater 5. A gas feed water heater outlet exhaust gas temperature signal e is supplied from the temperature detector 45 to a control loop described later provided in the deaerator water level control device 31.

FIG. 5 shows the details of the deaerator water level control device 31. The deaerator water level control device 31 includes a deaerator water level control valve control circuit, a condensate temperature control valve control circuit (both not shown), and a condensate release control valve control circuit 46. The condensate release control valve control circuit 46 controls the control loop 31,
40 and control loops 43 and 23. Also,
A switch 48 is provided for switching the condensate release flow rate request signal from these control loops 31, 40, 43, 23 with a signal provided from the switch 47 and outputting the signal.

Further, the condensate release control valve control circuit 46 provides a return corresponding to a deviation between the detected exhaust gas temperature signal e at the gas feed water heater outlet and a set value based on a predetermined exhaust gas temperature (π). A control loop 49 for outputting a water release flow rate request signal is provided. Further, a high value selection circuit 50 for selecting a high value from the condensate release flow rate request signal and outputting an opening command to the condensate release control valve 11 is provided.

The present embodiment has the above-described structure, and the gas feed water heater outlet condensate temperature control valve is mainly controlled by a gas feed water heater outlet condensate temperature control valve control circuit (not shown) while the plant reaches a specified load from the start of the plant. 8 is adjusted,
The deaerator water level is kept constant. When the deaerator water level exceeds the standard water level, a condensate release flow request signal from the control loop 39 is given to the condensate release control valve 11 via the high value selection circuit 41, the switch 48 and the high value selection circuit 50. . As a result, it is possible to prevent the deaerator water level from rising above the standard water level.

On the other hand, when the load reaches the specified load, a signal is output from the switch 47 to the switch 48, and a command from the control loop 43 is output to the condensate relief control valve 11.
As a result, it is possible to suppress the deaerator water level from rising significantly from the standard water level.

Further, during operation at the specified load, the temperature of the exhaust gas passing through the gas feed water heater 5 gradually increases. This exhaust gas temperature is detected by the temperature detector 45, and an exhaust gas temperature signal e at the gas feed water heater outlet is supplied to the control loop 49. In a control loop 49 in which a predetermined exhaust gas temperature is set as a set value, the exhaust gas temperature signal e at the gas feed water heater outlet is compared with the set value, and when the exhaust gas temperature signal e exceeds the set value, condensing according to the deviation is performed. The release flow request signal is output to the condensate release control valve 11 via the high value selection circuit 50.
Thereby, the condensate release control valve 11 is opened, and a part of the condensate flowing toward the deaerator 3 flows through the condensate discharge pipe 10 to the condenser 9. By maintaining the flow of the condensate water, the amount of condensate flowing into the deaerator 3 is reduced, and the deaerator water level is maintained at the standard water level.

On the other hand, in the gas feed water heater 5 using the exhaust gas as the heating medium, the flow of the condensate as the medium to be heated is maintained.
Heat exchange is performed between the exhaust gas and the exhaust gas that is continuously sent. At this time, the exhaust gas loses sensible heat and the temperature decreases. For this reason, the exhaust gas temperature becomes a low temperature that can be released into the atmosphere.

Thus, even when the exhaust gas temperature becomes high,
The operation of the gas feed water heater 5 can be continued while the condensate is returned to the condenser 9 while maintaining the opening of the condensate release control valve 11 corresponding to the temperature change.

According to the present embodiment, the gas feed water heater 5 can be operated while maintaining a predetermined condensate flow rate at a predetermined exhaust gas temperature at the gas feed water heater outlet, and the thermal efficiency of the plant can be reduced. It is possible to stably maintain the deaerator water level at the standard water level while maintaining good conditions. Further, the exhaust gas temperature can be reduced to a temperature at which the exhaust gas can be released into the atmosphere.

[0046]

According to the present invention, even when the deaerator water level fluctuates excessively, the deaerator water level can be stably maintained at the standard water level by adjusting the opening of the condensate release control valve. it can. Also, when the condensate temperature at the outlet of the gas feed water heater becomes high, the condensate temperature flowing into the deaerator can be reduced to a desired temperature by adjusting the opening of the condensate release control valve.

Further, according to the present invention, it is possible to stably maintain the deaerator water level at the standard water level while maintaining good thermal efficiency of the plant.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of a deaerator water level control device (until a specified load is reached) according to the present invention.

FIG. 2 is a block diagram showing an embodiment of a deaerator water level control device (after reaching a specified load) according to the present invention.

FIG. 3 is a configuration diagram of a combined cycle power plant including a deaerator water level control device according to the present invention.

FIG. 4 is a configuration diagram of a combined cycle power plant including the deaerator water level control device according to the present invention.

FIG. 5 is a block diagram showing another embodiment of the present invention.

FIG. 6 is a configuration diagram of a combined cycle power plant including a conventional deaerator water level control device.

FIG. 7 is a block diagram showing an example of a conventional deaerator water level control device (until a specified load is reached).

FIG. 8 is a block diagram showing an example of a conventional deaerator water level control device (after reaching a specified load).

[Description of Signs] 3 Deaerator 5 Gas feed water heater 8 Gas feed water heater outlet condensate temperature control valve 11 Condensate release control valve 16, 21, 22, 23, 37, 39, 40, 43, 4
9 Control loop 20, 24, 41, 44, 50 High value selection circuit 38 Low value selection circuit

Claims (3)

[Claims] 1. A deaerator water level control valve control circuit for adjusting an opening degree of a deaerator water level control valve, and a condensate temperature control valve control circuit for adjusting an opening degree of a gas feed water heater outlet condensate temperature control valve. And a condensate release control valve control circuit for adjusting the degree of opening of the condensate release control valve, wherein the condensate temperature control valve control circuit controls the detected deaerator water level signal and a predetermined set value. A first control loop that outputs a condensate flow rate request signal in accordance with the deviation, and outputs a condensate flow rate request signal in accordance with a deviation between a detected gas supply water heating outlet condensate temperature signal and a predetermined set value; A second control loop, of these condensate flow rate request signals,
It has a low value selection circuit that outputs either one as a command to determine the opening degree of the gas feed water heater outlet condensate temperature control valve, the condensate release control valve control circuit detects the deaerator water level signal and A third control loop for outputting a condensate release amount request signal in accordance with a deviation from a predetermined set value, the detected condensate temperature signal of the gas feed water heater outlet and the predetermined set value A fourth control loop that outputs a condensate release flow rate request signal in accordance with the deviation; and a fourth control loop that outputs one of these condensate release flow rate request signals as a command to determine the opening degree of the condensate release control valve. A deaerator water level control device comprising the high value selection circuit of 1. 2. A deaerator water level control valve control circuit for adjusting an opening degree of a deaerator water level control valve, and a condensate temperature control valve control circuit for adjusting an opening degree of a gas feed water heater outlet condensate temperature control valve. And a condensate release control valve control circuit for adjusting the opening of the condensate release control valve, wherein the condensate temperature control valve control circuit detects a deaerator water level signal to be detected, and a predetermined set value. A fifth control loop that outputs a condensate flow rate request signal in accordance with the deviation of
A sixth control loop that outputs a condensate flow rate request signal in accordance with a deviation between the detected gas feed water heater outlet condensate temperature signal and a predetermined set value, among these condensate flow rate request signals, A second high value selection circuit that outputs one of them as a command for determining an opening degree of the condensate temperature control valve at the gas feed water heater outlet, wherein the condensate release control valve control circuit is configured to detect a deaerator water level to be detected. A seventh control loop for outputting a condensate escape flow rate request signal in accordance with a deviation between the signal and a predetermined set value, a detected gas feed water heater outlet condensate temperature signal, and a predetermined set value An eighth control loop for outputting a condensate release flow rate request signal in accordance with the deviation from the above, and outputting any one of these condensate release flow rate request signals as a command for determining the opening degree of the condensate release control valve. A third high value selection circuit Deaerator water level control device comprising Te. 3. A deaerator water level control valve control circuit for adjusting an opening of a deaerator water level control valve, and a condensate temperature control valve control circuit for adjusting an opening of a gas feed water heater outlet condensate temperature control valve. And a condensate release control valve control circuit for adjusting the degree of opening of the condensate release control valve, the deaerator water level signal detected by the condensate release control valve control circuit, and a predetermined set value. A third control loop for outputting a condensate release flow rate request signal in accordance with the deviation of the condensate release flow rate signal, and a condensate release flow rate in accordance with a deviation between the detected gas feed water heater outlet condensate temperature signal and a predetermined set value. A fourth control loop that outputs a request signal, a first high value selection circuit that outputs one of these condensate release flow rate request signals as a command to determine the opening of the condensate release control valve, Between the deaerator water level signal and a predetermined set value. A seventh control loop for outputting a condensate escape amount request signal in response to the condensate escape flow rate request signal in accordance with a deviation between the detected gas feed water heater outlet condensate temperature signal and a predetermined set value. An eighth control loop to be output, a third high value selection circuit that outputs one of these condensate release flow rate request signals as a command to determine the opening of the condensate release control valve, and a load signal. A means for switching and outputting the opening degree command to the condensate release control valve to any one, a condensate release according to a deviation between a detected gas feed water heater outlet exhaust gas temperature signal and a predetermined set value. A ninth control loop for outputting a flow rate request signal, an opening command to the condensate relief valve based on the condensate release flow rate request signal from the ninth control loop, and a third control loop;
Deaerator water level control including a fourth high value selection circuit that outputs one of the opening degree commands to the condensate relief valve based on the condensate release flow rate request signal from 4, 7, 8 apparatus.