nuclear power unit system

Abstract

This invention provides a nuclear power unit system comprising: a high-pressure cylinder; a deaerator for deoxygenating condensate entering the deaerator using steam output from the high-pressure cylinder; a main steam system for providing first auxiliary steam to the deaerator; an auxiliary steam system for providing second auxiliary steam to the deaerator, enabling the deaerator to operate under no-load constant-pressure conditions; a pressure detection module for acquiring the deaerator pressure; a first-order hysteresis module for issuing a trigger signal when the turbine of the nuclear power unit experiences a load shedding condition based on the deaerator pressure; and a regulating module for maintaining the deaerator pressure at the pre-load shedding pressure for a preset time and then decreasing it at a preset rate upon receiving the trigger signal. This invention introduces a first-order inertial filtering module, which can accurately identify deaerator pressure changes, thereby accurately detecting turbine load shedding conditions, ensuring deaerator pressure stability, and contributing to the long-term stable operation of the nuclear power unit.

Description

Technical Field

[0001] This invention relates to the field of nuclear power units, and more specifically to a nuclear power unit system. Background Technology

[0002] During operation, nuclear power units inevitably experience rapid load shedding, also known as load drop, due to faults in the external power grid, main unit, or auxiliary systems. This rapid load shedding often leads to a rapid drop in deaerator pressure. The drop in deaerator pressure prevents the main feedwater from being heated, and even after the fault is cleared, the unit cannot quickly return to its original load condition for continued operation.

[0003] Currently, a complex combination of multiple signals, such as turbine shutdown signal, reactor shutdown signal, and turbine islanding operation, is commonly used to identify load shedding conditions. This approach can identify large-scale load shedding conditions of certain units, but it cannot accurately detect other rapid load reduction conditions of other units that do not trigger turbine shutdown, reactor shutdown, and turbine islanding operation, which lead to turbine load shedding conditions. Therefore, it cannot guarantee the pressure stability of the deaerator under these conditions, which is not conducive to the long-term stable operation of nuclear power units. Summary of the Invention

[0004] To address the aforementioned technical problems, the present invention aims to provide a nuclear power unit system that can accurately detect the turbine's load shedding condition, ensure stable deaerator pressure, and facilitate the long-term stable operation of the nuclear power unit.

[0005] The technical solution adopted in this invention is as follows:

[0006] An embodiment of the present invention proposes a nuclear power unit system comprising: a high-pressure cylinder; a deaerator connected to the exhaust port of the high-pressure cylinder via a first regulating valve for deoxygenating condensate entering the deaerator using steam output from the high-pressure cylinder; a main steam system connected to the deaerator via a second regulating valve for providing first auxiliary steam to the deaerator to maintain stable deaerator pressure under load shedding conditions; an auxiliary steam system connected to the deaerator via a third regulating valve for providing second auxiliary steam to the deaerator to enable the deaerator to operate under no-load constant pressure conditions; a pressure detection module installed on the deaerator for acquiring the deaerator pressure; a first-order hysteresis module for determining whether the turbine of the nuclear power unit is experiencing load shedding based on the deaerator pressure, and issuing a trigger signal when the turbine is determined to be experiencing load shedding; and a regulating module for controlling the second regulating valve upon receiving the trigger signal to maintain the deaerator pressure at a preset time before load shedding and then decrease it at a preset rate.

[0007] In addition, the nuclear power unit system proposed according to the present invention may also have the following additional technical features:

[0008] According to one embodiment of the present invention, the pressure detection module includes a first pressure transmitter, a second pressure transmitter, and a third pressure transmitter. The pressure detection module is used to: obtain the pressure of the deaerator based on the median pressure detected by the first, second, and third pressure transmitters when all three transmitters are functioning correctly; obtain the pressure of the deaerator based on the average pressure detected by the two transmitters that are functioning correctly when any one of the first, second, and third pressure transmitters fails; obtain the pressure of the deaerator based on the pressure detected by the transmitters that are functioning correctly when any two of the first, second, and third pressure transmitters fail; and obtain the pressure of the deaerator based on the pressure detected by the transmitters that are functioning correctly when all three transmitters fail. By setting up three pressure transmitters, the failure of a single pressure transmitter can prevent the inability to obtain the pressure of the deaerator, thus ensuring a continuous and stable pressure of the deaerator.

[0009] According to an embodiment of the present invention, the transfer function of the first-order hysteresis module is obtained according to the following formula: Where τ is the filtering time and s is a variable. The first-order hysteresis module calculates the deaerator pressure based on the transfer function, which can effectively suppress periodic interference signals in the deaerator pressure signal, and obtain accurate deaerator pressure values. It is suitable for situations where the deaerator pressure fluctuation frequency is high.

[0010] According to one embodiment of the present invention, τ = 10s. When the filtering time is set to 10s, the first-order hysteresis module can adapt to rapid changes in deaerator pressure, and its filtering results can be output in a timely manner with high sensitivity. It can also prevent the occurrence of false identification of load shedding conditions due to excessive sensitivity and inability to effectively filter out interference.

[0011] According to one embodiment of the present invention, the first-order hysteresis module is specifically used to: determine that the turbine is experiencing a load shedding condition when the pressure reduction rate of the deaerator reaches 80 kPa / 10 s or the pressure drops by 80 kPa stepwise.

[0012] According to one embodiment of the present invention, the regulating module specifically includes: a given function generator, used to generate a pressure holding curve based on the pressure of the deaerator before load shedding when the trigger signal is received. The pressure change of the pressure holding curve is as follows: first, the pressure of the deaerator before load shedding is maintained for 300 seconds, and then reduced to 0 at 0.1 MPa / min; and a PID controller (Proportion-Integration-Derivative controller), used to control the second regulating valve according to the pressure holding curve so that the pressure of the deaerator changes according to the pressure holding curve. When the turbine experiences load shedding, controlling the pressure change of the deaerator according to the pressure holding curve by the given function generator and the PID controller can effectively prevent the auxiliary steam system safety valve from opening due to overpressure caused by a sudden decrease in steam consumption, thus ensuring the safe operation of the deaerator.

[0013] The beneficial effects of this invention are:

[0014] According to the nuclear power unit system of the present invention, the pressure change of the deaerator is obtained through the pressure detection module, and a first-order hysteresis module is set to determine whether the turbine is experiencing a load shedding condition based on the pressure change of the deaerator. During the load shedding condition, the pressure of the deaerator is controlled by the adjustment module to maintain the pressure of the deaerator at the pressure before the load shedding for a period of time. Thus, the load shedding condition of the turbine can be accurately detected, ensuring the pressure stability of the deaerator, which is conducive to the long-term stable operation of the nuclear power unit. Attached Figure Description

[0015] Figure 1 This is a block diagram of a nuclear power unit system according to an embodiment of the present invention;

[0016] Figure 2 This is a block diagram of a pressure detection module according to an embodiment of the present invention;

[0017] Figure 3 This is a schematic diagram of the pressure holding curve according to an embodiment of the present invention. Detailed Implementation

[0018] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0019] like Figure 1As shown, the nuclear power unit system of this embodiment includes a high-pressure cylinder 100, a deaerator 200, a main steam system 300, an auxiliary steam system 400, a pressure detection module 500, a first-order hysteresis module 600, a regulating module 700, a first regulating valve 800, a second regulating valve 900, and a third regulating valve 1000. The deaerator 200 is connected to the exhaust port of the high-pressure cylinder 100 via the first regulating valve 800, and is used to deoxygenate the condensate entering the deaerator using steam output from the high-pressure cylinder 100. The main steam system 300 is connected to the deaerator 200 via the second regulating valve 900, and is used to provide first auxiliary steam to the deaerator 200 to maintain stable pressure in the deaerator 200 under load shedding conditions. The auxiliary steam system 400 is connected to the deaerator 200 via the third regulating valve 1000, and is used to provide first auxiliary steam to the deaerator 200 via the third regulating valve 1000. A second auxiliary steam is provided to enable the deaerator 200 to operate under no-load constant pressure conditions. A pressure detection module 500 is installed on the deaerator 200 and is used to acquire the pressure of the deaerator 200. A first-order hysteresis module 600 is used to determine whether the turbine of the nuclear power unit is experiencing a load shedding condition based on the pressure of the deaerator 200, and sends a trigger signal when the turbine is determined to be experiencing a load shedding condition. A regulating module 700 is used to control the second regulating valve 900 when the trigger signal is received, so that the pressure of the deaerator 200 is maintained at the pressure before the load shedding for a preset time and then decreases at a preset rate.

[0020] Specifically, the first regulating valve can be a pneumatic on / off valve. The deaerator 200 uses steam to heat and disperse the condensate entering the deaerator, ultimately removing oxygen from the condensate to achieve deaeration. The steam can come from the high-pressure cylinder 100, the main steam system 300, and the auxiliary steam system 400. The regulating module 700 can control the opening of the second regulating valve 900 and the third regulating valve 1000 to use auxiliary steam to adjust the pressure of the deaerator 200 according to actual needs, maintaining the deaerator pressure at the set pressure. When the deaerator water level is too high, the second regulating valve 900 and the third regulating valve 1000 automatically close to prevent turbine water ingress accidents.

[0021] like Figure 1 As shown, based on the different operating conditions of the turbine in the nuclear power unit system, the operating modes of deaerator 200 can be divided into the following four types:

[0022] The first operating mode: When the turbine of the nuclear power unit is under no-load operation, the deaerator 200 operates at a constant pressure. During the start-up phase, when the turbine is under no-load operation, the auxiliary steam system 400 and the third regulating valve 1000 provide second auxiliary steam to the deaerator 200, maintaining it at a constant pressure below the set pressure. The reference value for this pressure is 0.12 MPa(a), which can be adjusted according to specific circumstances.

[0023] The second operating mode: When the turbine of the nuclear power unit is under low load, the deaerator 200 operates at a constant pressure. When the turbine load is at a low level and gradually increases, the main steam system 300 and the pressure-stabilizing steam regulating valve, i.e., the second regulating valve 900, provide the deaerator 200 with first auxiliary steam, so that the deaerator 200 maintains constant pressure operation at pressure two. The reference value of pressure two is 0.17 MPa(a), which can be adjusted according to specific conditions.

[0024] The third operating mode: During normal operation of the nuclear power unit's turbine, the deaerator 200 operates under sliding pressure. When the turbine is operating normally, if the exhaust pressure from the high-pressure cylinder 100 to the deaerator 200 is greater than pressure two, the deaerator 200 can deoxygenate the steam output from the high-pressure cylinder 100. The deaerator 200 can also supply steam to the high-pressure cylinder 100 through the first regulating valve 800, thus achieving sliding pressure operation of the deaerator 200 based on the exhaust pressure from the high-pressure cylinder 100 to the deaerator 200. The exhaust pressure from the high-pressure cylinder 100 to the deaerator 200 (the deaerator pressure) is a function of the turbine load. The first-order lag module 600 calculates the load change in real time based on the deaerator pressure to determine whether a load shedding condition has occurred.

[0025] The fourth operating mode: When the turbine of the nuclear power unit is in a load shedding condition, the deaerator 200 is pressure controlled. When the turbine experiences load shedding, the second regulating valve 900 is controlled by the regulating module 700 to regulate the pressure of the deaerator 200, thereby controlling the steam output of the deaerator 200, ensuring that the feedwater continues to be heated and that the feedwater pump does not experience cavitation.

[0026] When the first-order lag module 600 tracks the ramp signal in steady state, the rate of change of the input and output signals of the system are exactly equal. However, due to the inertia of the system, when the input signal c(t) rises from 0 to 1, the corresponding output signal lags behind the input signal by a constant T. Therefore, it can also be called a first-order lag element.

[0027] The pressure detection module 500 acquires the pressure of the deaerator 200 in real time, i.e., the exhaust pressure from the high-pressure cylinder 100 to the deaerator 200. The first-order hysteresis module 600 determines whether the turbine is experiencing a load shedding condition based on the pressure of the deaerator 200, and sends a trigger signal to the regulating module 700 when the turbine is determined to be experiencing a load shedding condition. Upon receiving the trigger signal, the regulating module 700 controls the opening of the second regulating valve 900, so that the pressure of the deaerator 200 is maintained at the pressure before the load shedding for a preset time (e.g., 300s) before decreasing at a preset rate. Therefore, by not employing multi-signal combination logic, the logic for determining load shedding conditions is simplified. Only the most direct signal, the deaerator pressure, is used, allowing for accurate identification of deaerator pressure changes. This, in turn, enables precise detection of turbine load shedding conditions. Upon detecting turbine load shedding, the deaerator pressure is maintained at the pre-load shedding pressure for a period before decreasing to meet the main feedwater pump's suction head requirements and ensure continuous heating of condensate. This allows the unit to quickly return to its original load setpoint after troubleshooting, thus maintaining stable unit operation. Figure 2 As shown, in one embodiment of the present invention, the pressure detection module 500 may include a first pressure transmitter 510, a second pressure transmitter 520, and a third pressure transmitter 530. When all three pressure transmitters are functioning correctly, the pressure detection module 500 obtains the pressure of the deaerator 200 based on the median pressure detected by the three transmitters. When any one of the three transmitters fails, the pressure detection module 500 obtains the pressure of the deaerator 200 based on the average pressure detected by the two transmitters that are functioning correctly. When any two of the first pressure transmitter 510, the second pressure transmitter 520, and the third pressure transmitter 530 fail, the pressure detection module 500 obtains the pressure of the deaerator 200 based on the pressure detected by the pressure transmitter that has not failed; when all three pressure transmitters fail, the pressure detection module 500 obtains the pressure of the deaerator 200 based on the last valid value detected by the first pressure transmitter 510, the second pressure transmitter 520, and the third pressure transmitter 530.

[0028] Specifically, the deaerator 200 detects its pressure through the pressure detection module 500, employing a three-out-of-three logic method. The specific processing logic is as follows: when all transmitters are functioning correctly, the output is the median value; when one transmitter fails, the output is the average of the other two normally functioning transmitters; when two transmitters fail, the output is the value of the remaining normally functioning transmitter; when all three transmitters fail, the output retains the last valid value. The pressure detection module 500 outputs both the pressure signal of the deaerator 200 and the transmitter fault signal.

[0029] The pressure signal from the deaerator 200 output by the pressure detection module 500 will be used as the controlled variable during the operation of the deaerator 200. When two of the three pressure transmitters fail, the pressure control of the deaerator 200 switches to manual control. When the pressure value of the deaerator 200 is too high, an alarm will be triggered on the DCS (Distributed Control System) operator station.

[0030] In one embodiment of the present invention, the transfer function of the first-order hysteresis module 600 can be obtained according to the following formula: Where τ is the filtering time, for example, τ = 10s, and s is a variable.

[0031] In one embodiment of the present invention, the first-order hysteresis module 600 can determine that the turbine is experiencing a load shedding condition when the pressure reduction rate of the deaerator 200 reaches 80 kPa / 10 s or the pressure drops by 80 kPa stepwise. The pressure of the deaerator 200 is the exhaust pressure from the high-pressure cylinder 100 to the deaerator 200.

[0032] It should be noted that the first-order hysteresis module 600, based on the direct signal of the exhaust pressure from the high-pressure cylinder 100 to the deaerator 200, determines the occurrence of load shedding conditions by judging the rate of change of the exhaust pressure from the high-pressure cylinder 100 to the deaerator 200. Since the pressure signal detected by the pressure detection module 500 itself has a jittering characteristic, the first-order hysteresis module 600 can suppress the periodic interference of the pressure signal by setting a transfer function, thus obtaining accurate information on the exhaust pressure changes from the high-pressure cylinder 100 to the deaerator 200. The selection of the filtering time τ is crucial to the accuracy of the first-order hysteresis module 600's judgment. The filtering time τ must be able to adapt to the rapid changes in the exhaust pressure from the high-pressure cylinder 100 to the deaerator 200, ensuring that the filtering result keeps up with the changes and obtains sufficient sensitivity, while also preventing overly sensitive filtering that could lead to misidentification of load shedding conditions. Therefore, based on the characteristics of turbine load shedding—that is, the greater the rate of decrease in exhaust pressure from high-pressure cylinder 100 to deaerator 200, the shorter the time required for the exhaust pressure to decrease—a filtering time τ = 10s is selected, and the critical value for the trigger signal, the rate of decrease in exhaust pressure from high-pressure cylinder 100 to deaerator 200, is set to 80 kPa / 10s. When the first-order hysteresis module 600 detects that the rate of decrease in exhaust pressure from high-pressure cylinder 100 to deaerator 200 reaches 80 kPa / 10s or that the pressure drops by 80 kPa, it determines that the turbine is experiencing load shedding.

[0033] In one embodiment of the present invention, the regulating module 700 may include a given function generator and a PID controller. The given function generator is used to generate a pressure holding curve based on the pressure of the deaerator 200 before load shedding upon receiving a trigger signal; the PID controller is used to control the second regulating valve 900 according to the pressure holding curve, so that the pressure of the deaerator 200 changes according to the pressure holding curve. As an example, such as... Figure 3 As shown, the pressure change in the pressure holding curve can be as follows: first, the pressure of the deaerator 200 before load shedding is maintained for 300 seconds, and then reduced to 0 at a rate of 0.1 MPa / min. Figure 3 The horizontal axis represents time, and the vertical axis represents the pressure of the deaerator.

[0034] Specifically, when a unit malfunction causes the turbine to experience load shedding, the first-order lag module 600 determines that the turbine is experiencing load shedding and outputs a trigger signal. Upon receiving the trigger signal, the setpoint function generator of the regulating module 700 generates a pressure-holding curve based on the pressure of the deaerator 200 before load shedding. The regulating module 700, through a PID controller, controls the second regulating valve 900 to open rapidly according to the pressure-holding curve. A large amount of first auxiliary steam from the main steam system 300 is then supplied to the deaerator 200 to maintain the pressure of the deaerator 200 before the turbine experienced load shedding, thus meeting the head requirements of the main feedwater pump and ensuring continuous heating of the condensate. The reference set pressure-holding time is 300 seconds, which can be adjusted according to specific circumstances. If the unit malfunction is resolved within the pressure-holding time, the stable pressure of the deaerator 200 creates conditions for the unit to resume load to its original state, enabling the unit to achieve continuous and stable operation. After a 300-second pressure holding period, the PID controller slowly closes the second regulating valve 900, causing the pressure in the deaerator 200 to drop to 0 at a rate of 0.1 MPa / min. This effectively prevents the second regulating valve 900 from opening due to overpressure caused by a sudden decrease in gas consumption. Subsequently, the setpoint function generator output tracks the deaerator pressure, and the PID controller output is zero.

[0035] According to the nuclear power unit system of the present invention, the pressure change of the deaerator is obtained through the pressure detection module, and a first-order hysteresis module is set to determine whether the turbine is experiencing a load shedding condition based on the pressure change of the deaerator. During the load shedding condition, the pressure of the deaerator is controlled by the adjustment module to maintain the pressure of the deaerator at the pressure before the load shedding for a period of time. Thus, the load shedding condition of the turbine can be accurately detected, ensuring the pressure stability of the deaerator, which is conducive to the long-term stable operation of the nuclear power unit.

[0036] In the description of this invention, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. "A plurality of" means two or more, unless otherwise explicitly specified.

[0037] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Furthermore, those skilled in the art can combine and integrate the different embodiments or examples and features of different embodiments or examples described in this specification without contradiction. Furthermore, those skilled in the art can combine and integrate the different embodiments or examples described herein, as well as the features of the different embodiments or examples, without contradiction.

[0038] It should be understood that various parts of the present invention can be implemented in hardware, software, firmware, or a combination thereof. In the above embodiments, multiple steps or methods can be implemented in software or firmware stored in memory and executed by a suitable instruction execution system. For example, if implemented in hardware as in another embodiment, it can be implemented using any of the following techniques known in the art, or a combination thereof: discrete logic circuits having logic gates for implementing logical functions on data signals, application-specific integrated circuits (ASICs) having suitable combinational logic gates, programmable gate arrays (PGAs), field-programmable gate arrays (FPGAs), etc.

[0039] Those skilled in the art will understand that all or part of the steps of the methods in the above embodiments can be implemented by a program instructing related hardware. The program can be stored in a computer-readable storage medium, and when executed, the program includes one or a combination of the steps of the method embodiments.

[0040] Furthermore, the functional units in the various embodiments of the present invention can be integrated into a processing module, or each unit can exist physically separately, or two or more units can be integrated into a module. The integrated module can be implemented in hardware or as a software functional module. If the integrated module is implemented as a software functional module and sold or used as an independent product, it can also be stored in a computer-readable storage medium.

[0041] The storage medium mentioned above can be a read-only memory, a disk, or an optical disk, etc. Although embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present invention.

[0042] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A nuclear power unit system, characterized in that, include: High-pressure cylinder; A deaerator is connected to the exhaust port of the high-pressure cylinder via a first regulating valve. The deaerator is used to deoxygenate the condensate entering the deaerator using the steam output from the high-pressure cylinder. A main steam system, which is connected to the deaerator via a second regulating valve, is used to provide the deaerator with first auxiliary steam. An auxiliary steam system is connected to the deaerator via a third regulating valve. The auxiliary steam system is used to provide second auxiliary steam to the deaerator through the third regulating valve so that the deaerator operates under no-load constant pressure conditions. A pressure detection module is installed on the deaerator and is used to obtain the pressure of the deaerator. A first-order hysteresis module is used to determine whether the turbine of the nuclear power unit is experiencing a load shedding condition based on the pressure of the deaerator, and to issue a trigger signal when it is determined that the turbine is experiencing a load shedding condition. The regulating module is used to control the second regulating valve when the trigger signal is received, so that the pressure of the deaerator is maintained at the pressure preset time before the load is shed and then decreases at a preset rate.

2. The nuclear power unit system according to claim 1, characterized in that, The pressure detection module includes a first pressure transmitter, a second pressure transmitter, and a third pressure transmitter, and the pressure detection mold body is used for: When the first pressure transmitter, the second pressure transmitter, and the third pressure transmitter are all functioning correctly, the pressure of the deaerator is obtained based on the median of the pressures detected by the first pressure transmitter, the second pressure transmitter, and the third pressure transmitter. When any one of the first pressure transmitter, the second pressure transmitter, and the third pressure transmitter fails, the pressure of the deaerator is obtained based on the average pressure detected by the two pressure transmitters that have not failed. When any two of the first pressure transmitter, the second pressure transmitter, and the third pressure transmitter fail, the pressure of the deaerator is obtained based on the pressure detected by the pressure transmitter that has not failed. When the first pressure transmitter, the second pressure transmitter, and the third pressure transmitter all fail, the pressure of the deaerator is obtained based on the last valid value detected by the first pressure transmitter, the second pressure transmitter, and the third pressure transmitter.

3. The nuclear power unit system according to claim 1, characterized in that, The transfer function of the first-order hysteresis module is obtained according to the following formula: Where τ is the filtering time and s is a variable.

4. The nuclear power unit system according to claim 3, characterized in that, τ = 10s.

5. The nuclear power unit system according to claim 4, characterized in that, The first-order hysteresis module is specifically used for: When the pressure drop rate of the deaerator reaches 80 kPa / 10 s or the pressure drops by 80 kPa step, it is determined that the turbine is in a load shedding condition.

6. The nuclear power unit system according to claim 1, characterized in that, The adjustment module specifically includes: A given function generator is used to generate a pressure holding curve based on the pressure of the deaerator before load shedding when the trigger signal is received. The pressure change of the pressure holding curve is as follows: first, the pressure of the deaerator before load shedding is maintained for 300 seconds, and then reduced to 0 at 0.1 MPa / min. A PID controller is used to control the second regulating valve according to the pressure holding curve, so that the pressure of the deaerator changes according to the pressure holding curve.

Images