Passive oxygen supplement device and control method thereof

Abstract

The application discloses a passive oxygen supplement device and a control method thereof. The device comprises a demineralized water source, a condensate pump, a venturi, the condensate pump, a supplement air filter screen, a low-pressure heater, an oxygen remover, a high-pressure heater and a steam generator. The outlet of the demineralized water source is divided into two paths, one of which is communicated with the inlet of the condensate pump, and the other is communicated with the inlet of the condensate pump through the venturi, and the supplement air filter screen is communicated with the inlet of the venturi. The outlet of the condensate pump is communicated with the inlet of the steam generator in sequence through the low-pressure heater, the oxygen remover and the high-pressure heater. The device and the control method thereof can realize safe and reliable oxygen supplement.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of water supply oxygenation, and relates to a passive oxygen supplement device and a control method thereof. BACKGROUND

[0002] As one of the advanced water supply treatment processes for current direct-current units, water supply oxygenation can form a dense oxide protective layer on the inner wall of the pipeline, thereby effectively reducing the corrosion and fouling rate of thermal equipment, reducing the frequency of chemical cleaning, prolonging the operation cycle of polishing treatment, saving the operation and maintenance cost of the power plant, and improving the economy of the power plant.

[0003] The most commonly used oxygenation methods for water supply oxygenation include pure oxygen, air and oxygen-rich water. In the case of system pressure fluctuation, gaseous oxygenation such as pure oxygen or air is compressed in the oxygenation pipeline, and the oxygen injection amount also fluctuates, making it difficult to accurately control the oxygenation amount, resulting in unstable control of the oxygenation amount of the water supply, which may cause the oxygen content of the water supply to exceed the standard. The liquid oxygen-rich water oxygenation medium has the characteristic of being incompressible, and when the system pressure fluctuation changes cause the pressure at the oxygenation point to change, the liquid is almost incompressible, so the oxygenation amount at the oxygenation point is relatively stable compared to gaseous oxygenation, but there is a high concentration of dissolved oxygen in the oxygen-rich water, and when the unit needs to control the oxygen content in a lower range, a small fluctuation in the flow of oxygen-rich water may cause the oxygen content in the water to fluctuate beyond the allowed range.

[0004] The scheme of patent (CN210979797 U) is to add condensate water to the water supply, so that the dissolved oxygen in the condensate water is brought into the water supply system, so that the oxygen concentration in the water supply meets the standard requirements. The problem with this method is that the unit needs more oxygen during the oxygenation conversion stage, which means that more water needs to be added to the water supply or the oxygenation conversion time needs to be extended.

[0005] The scheme of patent (CN202220260482.4) is to use an automatic adjusting closed-loop control system to solve the problem of oxygenation adjustment accuracy, but due to the system capacity inertia, there is a time difference of about 10-30 minutes between the oxygenation point and the sampling point, and each unit is different, and the system capacity is also different under different loads of the same unit. The above scheme cannot solve the control overshoot problem under closed-loop control, which may cause large fluctuations in the oxygen content of the water supply or even exceed the upper limit, and the oxygenation mode of the above scheme has a lag.

[0006] In fact, the current pure oxygen or oxygen-rich water oxygenation method has the problem that the unit load changes or the operation control stability of the system itself causes the unit water supply oxygen to exceed the standard, especially in low-oxygen operation conditions, unexpected fluctuations may cause the water supply oxygen to exceed the standard by dozens of times, and the excess oxygen entering the system may bring unexpected risks, which are incompatible with the safety concept of nuclear power units, so a relatively safer oxygenation method is needed. SUMMARY

[0007] The present application aims to overcome the above-mentioned drawbacks of the prior art, and provides a passive oxygen supplement device and a control method thereof, which can achieve safe and reliable oxygen supplement.

[0008] To achieve the above-mentioned purpose, the present application discloses a passive oxygen supplement device, comprising a demineralized water source, a condensate pump, a Venturi tube, a condensate pump, an air supplement filter screen, a low-pressure heater, an oxygen remover, a high-pressure heater, and a steam generator.

[0009] The outlet of the demineralized water source is divided into two paths, one of which is connected to the inlet of the condensate pump, and the other is connected to the inlet of the condensate pump through the Venturi tube, and the air supplement filter screen is connected to the inlet of the Venturi tube.

[0010] The outlet of the condensate pump is connected to the inlet of the steam generator in sequence through the low-pressure heater, the oxygen remover, and the high-pressure heater.

[0011] Further, the outlet of the demineralized water source is connected to the inlet of the condensate pump in sequence through the condenser water supply valve and the condenser.

[0012] Further, the outlet of the demineralized water source is connected to the inlet of the condensate pump in sequence through the oxygen supplement main pipe pressure sensor, the oxygen supplement automatic regulating valve, the condensate oxygen supplement flowmeter, the Venturi tube, the oxygen supplement check valve, and the oxygen supplement manual valve.

[0013] Further, the air supplement filter screen is connected to the inlet of the Venturi tube in sequence through the air supplement automatic regulating valve and the air supplement manual regulating valve.

[0014] Further, the outlet of the condensate pump is connected to the inlet of the steam generator in sequence through the fine treatment outlet oxygen meter, the condensate flowmeter, the low-pressure heater, the oxygen remover inlet hydrogen conductivity meter, the oxygen remover inlet oxygen meter, the oxygen remover, the feedwater pump, the feedwater flowmeter, the high-pressure heater, the steam generator inlet hydrogen conductivity meter, and the steam generator inlet oxygen meter.

[0015] Further, the oxygen remover is connected to the oxygen remover operation exhaust valve and the oxygen remover start-up exhaust valve.

[0016] Further, it further comprises a control module, which is connected to the oxygen supplement main pipe pressure sensor, the oxygen supplement automatic regulating valve, the condensate oxygen supplement flowmeter, the air supplement automatic regulating valve, the fine treatment outlet oxygen meter, the condensate flowmeter, the oxygen remover inlet hydrogen conductivity meter, the oxygen remover inlet oxygen meter, the feedwater flowmeter, the steam generator inlet hydrogen conductivity meter, the steam generator inlet oxygen meter, the condensate pump, and the feedwater pump.

[0017] Further, the control module is a PLC or a power plant DCS.

[0018] The application discloses a control method of a passive oxygen supplement device.

[0019] 11) open the oxygen supplement total valve and the oxygen supplement manual valve, close the air supplement automatic regulating valve and the air supplement manual regulating valve, and the oxygen supplement automatic regulating valve is in a regulating state;

[0020] 12) because of the negative pressure at the inlet of the condensate pump, oxygen-containing desalted water in the desalted water source is sucked into the condensate pump;

[0021] 13) the opening degree of the oxygen supplement automatic regulating valve is adjusted to improve the desalted water flow in the system oxygenation conversion process, and then the oxygen content of the condensate water system is improved;

[0022] 14) when the flow measured by the condensate oxygen supplement flowmeter exceeds the water supplement of the system, the air supplement manual regulating valve is opened, the opening degree of the air supplement automatic regulating valve is adjusted, the air supplement oxygenation mode of the Venturi tube is adopted to improve the oxygenation of the system, and the oxygen content measured by the oxygen table at the outlet of the polishing treatment is close to the upper limit of the oxygen content, so that the oxygenation conversion efficiency of the system is improved;

[0023] 15) after the system oxygenation conversion is completed, the air supplement manual regulating valve and the air supplement automatic regulating valve are closed, and the oxygen supplement automatic regulating valve is controlled to be in an automatic regulating mode.

[0024] Further, the method further comprises:

[0025] 21) during the system oxidation operation, the air supplement manual regulating valve and the air supplement automatic regulating valve are in a closed state, and the oxygen supplement automatic regulating valve is in an automatic regulating mode;

[0026] 22) the deaerator operation exhaust valve and the deaerator start exhaust valve are in a normal closed state;

[0027] 23) the water supplement demand of the unit is firstly supplemented by the oxygen supplement circuit, and the insufficient water amount is further supplemented by the condenser water valve;

[0028] 24) the system flow signal Q is calculated according to the data Q1 measured by the condensate flowmeter and the data Q2 measured by the feedwater flowmeter, Q=K1Q1+(1-K1)Q2, and K1 is an oxygen supplement flow coefficient;

[0029] 25) the oxygen supplement automatic regulating valve is adjusted until the actual oxygen supplement flow Q0 measured by the condensate oxygen supplement flowmeter is consistent with the system flow signal Q; the oxygen supplement automatic regulating valve transiently responds while the condensate water or the feedwater flow changes;

[0030] 26) the oxygen-containing desalted water added by the oxygen supplement automatic regulating valve is regulated according to the proportional feedforward of the condensate water and the main feedwater flow.

[0031] The application has the following beneficial effects:

[0032] The passive oxygen supplement device and the control method thereof described in the application adopt the Venturi self-suction air oxygen supplement mode to improve the content of dissolved oxygen in water in the oxygenation conversion process, ensure the oxygenation conversion speed of the unit, and realize safe and reliable oxygenation.

[0033] Further, to avoid the problem that the feedwater oxygen content appears large fluctuation or even exceeds the upper limit due to the overshoot of the closed-loop control under different units and different load levels, the application adopts a feedforward proportional control mode, that is, the oxygenation flow rate and the condensate flow rate maintain a certain proportion, which can be synchronized with the change of the condensate flow rate, to avoid the hysteresis of the control. BRIEF DESCRIPTION OF DRAWINGS

[0034] The accompanying drawings, which form a part of this application, are included to provide a further understanding of the application and are incorporated in and constitute a part of this application. The embodiments of the application illustrated in the drawings are presented to explain and not to limit the present application. In the drawings:

[0035] Figure 1 The accompanying drawings, which form a part of this application, are included to provide a further understanding of the application and are incorporated in and constitute a part of this application. The embodiments of the application illustrated in the drawings are presented to explain and not to limit the present application. In the drawings:

[0036] In the drawings, 1 is a desalted water source, 2 is a condenser water supply valve, 3 is a condenser, 4 is a condensate pump, 5 is an oxygen supplement master valve, 6 is an oxygen supplement main pipe pressure sensor, 7 is an oxygen supplement automatic regulating valve, 8 is a condensate oxygenation flowmeter, 9 is a Venturi tube, 10 is an oxygen supplement check valve, 11 is an oxygen supplement manual valve, 12 is an air supplement filter screen, 13 is an air supplement automatic regulating valve, 14 is an air supplement manual regulating valve, 15 is a fine treatment outlet oxygen meter, 16 is a condensate flowmeter, 17 is a low-pressure heater, 18 is a deaerator inlet hydrogen conductivity meter, 19 is a deaerator inlet oxygen meter, 20 is a deaerator, 20-1 is a deaerator operation exhaust valve, 20-2 is a deaerator start exhaust valve, 21 is a feedwater pump, 22 is a feedwater flowmeter, 23 is a high-pressure heater, 24 is a steam generator inlet hydrogen conductivity meter, 25 is a steam generator inlet oxygen meter, 26 is a steam generator, and 27 is a control module. DETAILED DESCRIPTION

[0037] The technical solutions in the embodiments of the application will be clearly and completely described below with reference to the drawings in the embodiments of the application. Obviously, the described embodiments are only a part of the embodiments of the application, rather than all the embodiments of the application. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative work fall within the protection scope of the application.

[0038] In the description of the application, it should be understood that the terms "include" and "contain" indicate the presence of described features, whole, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, whole, steps, operations, elements, components and / or sets thereof.

[0039] It should also be understood that the terms used in the specification of the present application are used for the purpose of describing particular embodiments only and are not intended to limit the present application. As used in the specification and the appended claims of the present application, the singular forms "a," "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise.

[0040] It should be further understood that the term "and / or" used in the specification of the present application and the appended claims means one or more of the associated listed items as well as all possible combinations of the items and includes these combinations, for example, A and / or B can mean the three cases of A alone, A and B together, and B alone. In addition, the character " / " in the present application generally represents an "or" relationship between the objects before and after it.

[0041] It should be understood that, although the terms first, second, third, etc. can be employed in the embodiments of the present application to describe a certain range, etc., these ranges should not be limited to these terms. These terms are only used to distinguish the ranges from each other. For example, the first range can also be referred to as the second range, and similarly, the second range can also be referred to as the first range, without departing from the scope of the embodiments of the present application.

[0042] Depending on the context, the word "if" as used herein can be interpreted to mean "when" or "while" or "in response to determining" or "in response to detecting." Similarly, the phrase "if determined" or "if detecting (a stated condition or event)" can be interpreted to mean "when determined" or "in response to determining" or "when detecting (a stated condition or event)" or "in response to detecting (a stated condition or event)", depending on the context.

[0043] In order to make the purposes, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are some of the embodiments of the present application, rather than all the embodiments of the present application. The components of the embodiments of the present application described and shown in the drawings herein can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the claimed present application, but only represents selected embodiments of the present application. All other embodiments obtained by those of ordinary skill in the art without creative efforts based on the embodiments in the present application belong to the scope of protection of the present application.

[0044] Various structural diagrams according to the disclosed embodiments of the present application are shown in the accompanying drawings. These diagrams are not drawn to scale, in which certain details are exaggerated for clarity and others omitted. The shapes and relative sizes of the various regions, layers, and the relative positions of these regions / layers shown in the drawings are merely examples, and in actuality, they can be different due to manufacturing tolerances or technical limitations, and regions / layers with different shapes, sizes, and relative positions can be additionally designed according to actual needs by those skilled in the art.

[0045] Reference Figure 1 The passive oxygen supplement device includes a desalted water source 1, a condenser water supplement valve 2, a condenser 3, a condensate pump 4, an oxygen supplement total valve 5, an oxygen supplement main pipe pressure sensor 6, an oxygen supplement automatic regulating valve 7, a condensate oxygen supplement flowmeter 8, a Venturi tube 9, an oxygen supplement check valve 10, an oxygen supplement manual valve 11, an oxygen supplement air filter screen 12, an oxygen supplement air automatic regulating valve 13, an oxygen supplement air manual regulating valve 14, a polishing treatment outlet oxygen meter 15, a condensate flowmeter 16, a low-pressure heater 17, a deaerator inlet hydrogen conductivity meter 18, a deaerator inlet oxygen meter 19, a deaerator 20, a deaerator operation exhaust valve 20-1, a deaerator start exhaust valve 20-2, a feedwater pump 21, a feedwater flowmeter 22, a high-pressure heater 23, a steam generator inlet hydrogen conductivity meter 24, a steam generator inlet oxygen meter 25, a steam generator 26, and a control module 27.

[0046] The outlet of the desalted water source 1 is divided into two paths, one of which is connected to the inlet of the condensate pump 4 in sequence through the condenser water supplement valve 2 and the condenser 3, and the other of which is connected to the inlet of the condensate pump 4 in sequence through the oxygen supplement total valve 5, the oxygen supplement main pipe pressure sensor 6, the oxygen supplement automatic regulating valve 7, the condensate oxygen supplement flowmeter 8, the Venturi tube 9, the oxygen supplement check valve 10, the oxygen supplement manual valve 11, the oxygen supplement air filter screen 12, the oxygen supplement air automatic regulating valve 13, and the oxygen supplement air manual regulating valve 14.

[0047] The outlet of the condensate pump 4 is connected to the inlet of the steam generator 26 in sequence through the polishing treatment outlet oxygen meter 15, the condensate flowmeter 16, the low-pressure heater 17, the deaerator inlet hydrogen conductivity meter 18, the deaerator inlet oxygen meter 19, the deaerator 20, the feedwater pump 21, the feedwater flowmeter 22, the high-pressure heater 23, the steam generator inlet hydrogen conductivity meter 24, and the steam generator inlet oxygen meter 25.

[0048] The deaerator 20 is connected to the deaerator operation exhaust valve 20-1 and the deaerator start exhaust valve 20-2.

[0049] The dissolved oxygen in the desalted water used by the condensate water supplement of the unit per day is used as the oxygen source, the supplement of the unit per day is 0.5%-1.5%, the actual dissolved oxygen in the desalted water is more than 8000ppb, the dissolved oxygen in the system water can be increased by 40-120ppb, and the requirement of the oxidation operation condition of the unit is fully met. Based on the above actual situation, the supplement of the unit is used as the oxygen carrier, and the desalted water containing dissolved oxygen is added to the condensate water pump 4, which meets the supplement demand of the system and the requirement of the oxidation operation of the unit.

[0050] The condensate water pump 4 inlet mother pipe is in a negative pressure state, therefore, only needs to be connected to the condensate water pump 4 inlet from the desalted water through the adjusting valve, and the controllable oxygen supplement of the condensate water system can be realized by using the passive mode.

[0051] The oxygen conversion process adopts the self-suction air oxygen supplement mode of the Venturi tube 9 to increase the dissolved oxygen content in the water, and ensures the oxygen conversion speed of the unit.

[0052] In order to avoid the problem that the feedwater oxygen content appears large fluctuation or even exceeds the upper limit due to the overshoot of the closed-loop control under different units and different load levels, the present scheme adopts a feedforward proportional control mode, that is, the oxygen supplement flow and the condensate water flow maintain a certain proportion, which can be synchronized with the change of the condensate water flow, and the hysteresis of the control is avoided.

[0053] The control module 27 is a PLC or a power plant DCS. The control module 27 is connected with the oxygen supplement mother pipe pressure sensor 6, the oxygen supplement automatic adjusting valve, the condensate water oxygen supplement flowmeter 8, the air supplement automatic adjusting valve 13, the outlet oxygen table 15 of the polishing treatment, the condensate water flowmeter 16, the inlet hydrogen conductivity table 18 of the deaerator, the inlet oxygen table 19 of the deaerator, the feedwater flowmeter 22, the inlet hydrogen conductivity table 24 of the steam generator, the inlet oxygen table 25 of the steam generator, the condensate water pump 4 and the feedwater pump 21.

[0054] The control method of the passive oxygen supplement device comprises the following steps:

[0055] 1) System oxygen conversion process:

[0056] 11) In the system oxygen conversion process, the oxygen supplement total valve 5 and the oxygen supplement manual valve 11 are opened, the air supplement automatic adjusting valve 13 and the air supplement manual adjusting valve 14 are closed, and the oxygen supplement automatic adjusting valve 7 is in the adjusting state.

[0057] 12) Because of the negative pressure at the inlet of the condensate water pump 4, the oxygen-containing desalted water in the desalted water source 1 is sucked into the condensate water pump 4.

[0058] 13) The opening degree of the oxygen supplement automatic adjusting valve 7 is adjusted to increase the desalted water flow in the system oxygen conversion process, so as to increase the oxygen content of the condensate water system.

[0059] 14) When the flow measured by the condensate oxygen supplement flow meter 8 exceeds the water supplement of the system, open the air supplement manual regulating valve 14, adjust the opening of the air supplement automatic regulating valve 13, use the Venturi tube 9 to self-suck air to supplement oxygen, increase the oxygen supplement of the system, and ensure that the oxygen measured by the fine treatment outlet oxygen meter 15 is close to the upper limit of the oxygen, so as to improve the oxygen conversion efficiency of the system.

[0060] 15) After the oxygen conversion of the system is completed, close the air supplement manual regulating valve 14 and the air supplement automatic regulating valve 13, and control the oxygen supplement automatic regulating valve 7 to be in the automatic regulating mode.

[0061] 2) System normal oxidation operation:

[0062] 21) During the oxidation operation of the system, the air supplement manual regulating valve 14 and the air supplement automatic regulating valve 13 are in the closed state, and the oxygen supplement automatic regulating valve 7 is in the automatic regulating mode.

[0063] 22) The deaerator operation exhaust valve 20-1 and the deaerator start exhaust valve 20-2 are in the normal closed state, and the operation mode of being opened for 1-2 hours per week is adopted.

[0064] 23) The water supplement demand of the unit is first supplemented by the oxygen supplement circuit, and the insufficient water is further supplemented by the condenser water valve 2.

[0065] 24) The system flow signal Q is calculated according to the data Q1 measured by the condensate flow meter 16 and the data Q2 measured by the feedwater flow meter 22, Q=K1Q1+(1-K1)Q2, K1 is the oxygen supplement flow coefficient.

[0066] 25) Adjust the oxygen supplement automatic regulating valve 7 until the actual oxygen supplement flow Q0 measured by the condensate oxygen supplement flow meter 8 is consistent with the system flow signal Q, that is, the oxygen supplement flow Q0 measured by the condensate oxygen supplement flow meter 8 is proportional to the system flow signal Q; while the condensate or feedwater flow changes, the oxygen supplement automatic regulating valve 7 responds instantaneously.

[0067] 26) Because the oxygen concentration of the desalted water of the oxygen supplement device is much lower than that of the pure oxygen or the oxygen-rich water, the oxygen-containing desalted water added by the oxygen supplement automatic regulating valve 7 according to the proportional feedforward of the condensate and the main feedwater flow, the system oxygen concentration fluctuation is very low, generally 3-5pp.

[0068] 27) The above control processes are realized by the internal logic of the control module 27.

[0069] 3) System protection mode:

[0070] 31) When the air supplement automatic regulating valve 13 fails, manually open the air supplement automatic regulating valve 13 to full opening, and complete the oxygen conversion by manually adjusting the opening of the air supplement manual regulating valve 14.

[0071] 32) Alarm signal: when the pressure of the make-up oxygen main pressure sensor 6 is abnormal; the flow of the condensate make-up oxygen flow meter 8 is abnormal; the data of the purified water outlet oxygen meter 15, the deaerator inlet oxygen meter 19 and the steam generator inlet oxygen meter 25 is abnormal; the data of the deaerator inlet hydrogen conductivity meter 18 and the steam generator inlet hydrogen conductivity meter 24 is abnormal, an alarm signal is generated.

[0072] 33) Make-up oxygen automatic regulating valve 7 protection closing signal: when the pressure of the make-up oxygen main pressure sensor 6 is lower than the preset lower limit of pressure; the flow of the condensate make-up oxygen flow meter 8 is lower than the preset lower limit of flow; the data of the purified water outlet oxygen meter 15, the deaerator inlet oxygen meter 19 and the steam generator inlet oxygen meter 25 is abnormal; the data of the deaerator inlet hydrogen conductivity meter 18 and the steam generator inlet hydrogen conductivity meter 24 is abnormal, a make-up oxygen automatic regulating valve 7 protection closing signal is generated.

[0073] 34) Make-up oxygen automatic regulating valve 7 automatic closing signal: when the data of the condensate make-up oxygen flow meter 8 or the feed water flow meter 22 is lower than the preset lower limit of flow; the condensate and feed water pumps 21 are all shut down; the unit is shut down, a make-up oxygen automatic regulating valve 7 automatic closing signal is generated.

[0074] 35) The above control processes are realized by the internal logic of the control module 27.

[0075] Other embodiments of the application will be apparent to those skilled in the art from consideration of the specification and practice of the application disclosed herein. It is intended that the specification and examples be considered as exemplary only, with the true scope and spirit of the application being indicated by the following claims.

[0076] It is to be understood that the application is not limited to the precise construction here described and as shown in the attached drawings, and that various modifications and changes can be made by those skilled in the art without departing from the scope of the application. The scope of the application is to be interpreted only by the appended claims.

[0077] The above description is only the preferred embodiment of the present application, not any limitation to the present application, any simple modification, change and equivalent structure change according to the technical essence of the present application to the above embodiment, still belongs to the protection scope of the present application technical solution.

Claims

1. A passive oxygen supplementing device, characterized in that, The device comprises a demineralized water source (1), a condensate pump (4), a venturi (9), a condensate pump (4), an air supplement filter (12), a low-pressure heater (17), a deaerator (20), a high-pressure heater (23) and a steam generator (26); The outlet of the demineralized water source (1) is connected to the inlet of the condensate pump (4) through one path and connected to the inlet of the condensate pump (4) through the venturi (9) through another path, and the air supplement filter (12) is connected to the inlet of the venturi (9); The outlet of the condensate pump (4) is connected to the inlet of the steam generator (26) through the low-pressure heater (17), the deaerator (20) and the high-pressure heater (23) in sequence.

2. The passive oxygen supplementing device of claim 1, wherein, The outlet of the demineralized water source (1) is connected to the inlet of the condensate pump (4) through the condenser water supply valve (2) and the condenser (3) in sequence.

3. The passive oxygen supplementing device of claim 2, wherein, The outlet of the demineralized water source (1) is connected to the inlet of the condensate pump (4) through the oxygen supplement master valve (5), the oxygen supplement main pipe pressure sensor (6), the oxygen supplement automatic regulating valve (7), the condensate oxygen supplement flowmeter (8), the venturi (9), the oxygen supplement check valve (10) and the oxygen supplement manual valve (11) in sequence.

4. The passive oxygen supplementing device of claim 3, wherein, The air supplement filter (12) is connected to the inlet of the venturi (9) through the air supplement automatic regulating valve (13) and the air supplement manual regulating valve (14) in sequence.

5. The passive oxygen supplementing device of claim 4, wherein, The outlet of the condensate pump (4) is connected to the inlet of the steam generator (26) through the fine treatment outlet oxygen meter (15), the condensate flowmeter (16), the low-pressure heater (17), the deaerator inlet hydrogen conductivity meter (18), the deaerator inlet oxygen meter (19), the deaerator (20), the feedwater pump (21), the feedwater flowmeter (22), the high-pressure heater (23), the steam generator inlet hydrogen conductivity meter (24) and the steam generator inlet oxygen meter (25) in sequence.

6. The passive oxygen supplementing device of claim 5, wherein, The deaerator (20) is connected with a deaerator operation exhaust valve (20-1) and a deaerator start-up exhaust valve (20-2).

7. The passive oxygen supplementing device of claim 6, wherein, The device further comprises a control module (27) connected with the oxygen supplement main pipe pressure sensor (6), the oxygen supplement automatic regulating valve, the condensate oxygen supplement flowmeter (8), the air supplement automatic regulating valve (13), the fine treatment outlet oxygen meter (15), the condensate flowmeter (16), the deaerator inlet hydrogen conductivity meter (18), the deaerator inlet oxygen meter (19), the feedwater flowmeter (22), the steam generator inlet hydrogen conductivity meter (24), the steam generator inlet oxygen meter (25), the condensate pump (4) and the feedwater pump (21).

8. The passive oxygen supplementing device of claim 7, wherein, The control module (27) is a PLC or a power plant DCS.

9. A method for controlling the passive oxygen supplement device of claim 6, wherein, The device comprises the following steps: 11) opening the oxygen supplement master valve (5) and the oxygen supplement manual valve (11), closing the air supplement automatic regulating valve (13) and the air supplement manual regulating valve (14), and the oxygen supplement automatic regulating valve (7) is in a regulating state; 12) due to the negative pressure at the inlet of the condensate pump (4), the oxygen-containing demineralized water in the demineralized water source (1) is sucked into the condensate pump (4); 13) adjusting the opening degree of the oxygen supplement automatic regulating valve (7) to increase the flow of the demineralized water in the oxygen conversion process of the system, thereby increasing the oxygen content of the condensate water system; 14) When the flow measured by the condensate water oxygen supplement flowmeter (8) exceeds the water supplement of the system, open the air supplement manual regulating valve (14) and adjust the opening of the air supplement automatic regulating valve (13) to increase the oxygen supplement of the system by using the Venturi tube (9) to suck air and supplement oxygen, so as to ensure that the oxygen content measured by the outlet oxygen meter (15) is close to the upper limit of the oxygen content, thereby improving the oxygen conversion efficiency of the system; 15) After the oxygen conversion of the system is completed, close the air supplement manual regulating valve (14) and the air supplement automatic regulating valve (13), and control the oxygen supplement automatic regulating valve (7) to be in the automatic regulating mode.

10. The control method of the passive oxygen supplement device according to claim 9, wherein Also including: 21) During the oxidation operation of the system, the air supplement manual regulating valve (14) and the air supplement automatic regulating valve (13) are in the closed state, and the oxygen supplement automatic regulating valve (7) is in the automatic regulating mode; 22) The deaerator operation exhaust valve (20-1) and the deaerator start exhaust valve (20-2) are in the normal closed state; 23) The water supplement demand of the unit is first supplemented by the branch where the oxygen supplement total valve (5) is located, and the insufficient water is further supplemented by the condenser water valve (2); 24) The system flow signal Q is calculated according to the data Q1 measured by the condensate water flowmeter (16) and the data Q2 measured by the feedwater flowmeter (22), Q=K1Q1+(1-K1)Q2, K1 is the oxygen supplement flow coefficient; 25) Adjust the oxygen supplement automatic regulating valve (7) until the actual oxygen supplement flow Q0 measured by the condensate water oxygen supplement flowmeter (8) is consistent with the system flow signal Q; when the condensate water or feedwater flow changes, the oxygen supplement automatic regulating valve (7) responds instantaneously; 26) The oxygen-containing desalted water added by the oxygen supplement automatic regulating valve (7) is regulated according to the proportional feedforward of the condensate water and the main feedwater flow.

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