Passive oxygenating device and control method thereof

Abstract

The invention discloses a passive oxygen supplementation device and a control method thereof. The passive oxygen supplementation device comprises a desalting water source, a condensate pump, a Venturi tube, a condensate pump, an air supplementation filter screen, a low-pressure heater, a deaerator, a high-pressure heater and a steam generator. The outlet of the desalted water source is divided into two paths, one path is communicated with the inlet of the condensate pump, the other path is communicated with the inlet of the condensate pump through the Venturi tube, and the air supplementing filter screen is communicated with the inlet of the Venturi tube; and an outlet of the condensate pump is communicated with an inlet of the steam generator through the low-pressure heater, the deaerator and the high-pressure heater in sequence. By means of the device and the control method thereof, safe and reliable oxygen adding can be achieved.

Description

Technical Field

[0001] The invention belongs to the technical field of water supply oxygenation and relates to a passive oxygen supplementation device and a control method thereof. Background Art

[0002] As one of the most advanced feed water treatment processes for DC units, feed water oxygenation can form a dense oxide protective layer on the inner wall of the pipeline, thereby effectively reducing the corrosion and scaling rate of thermal equipment and the frequency of chemical cleaning, while extending the fine treatment operation cycle, saving power plant operation and maintenance costs and improving the economy of the power plant.

[0003] The most commonly used oxygenation methods for feed water are pure oxygen, air and oxygen-enriched water. In the case of system pressure fluctuations, gaseous oxygen such as pure oxygen or air is compressed in the oxygenation pipeline, and the oxygen injection volume will also fluctuate, making it difficult to achieve precise regulation of the oxygenation volume, resulting in unstable control of the feed water oxygenation volume, which may cause the feed water oxygen content to exceed the standard. The liquid oxygen-enriched water oxygenation medium has the characteristic of being incompressible. When the system pressure fluctuation changes and causes the pressure change at the oxygenation point, the liquid is almost incompressible, so the oxygenation volume at the oxygenation point is relatively stable relative to the gaseous state. However, there is a high concentration of dissolved oxygen in the oxygen-enriched water. When the unit needs to control the oxygen content in a low range, a slight fluctuation in the oxygen-enriched water flow rate may cause the oxygen content in the water to fluctuate beyond the allowable range.

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

[0005] The solution described in the patent (CN202220260482.4) is to use an automatically adjusted closed-loop control system to solve the problem of oxygen addition adjustment accuracy. However, due to the system capacity inertia, there is a time difference of about 10-30 minutes between the oxygen addition point and the sampling point. The situation of each unit is different, and the system capacity of the same unit is different under different loads. The above solution cannot solve the control overshoot problem under closed-loop control, which can easily lead to large fluctuations in the oxygen content of the water supply or even exceed the upper limit. At the same time, the oxygen addition mode of the above solution has a lag.

[0006] In fact, the current pure oxygen or oxygen-enriched water oxygenation methods all have the problem of excessive oxygen in the unit feed water due to changes in unit load or the system's own operating control stability. Especially under low-oxygen operating conditions, unexpected fluctuations can cause the feed water oxygen to exceed the standard by dozens of times. Excess oxygen entering the system may bring unexpected risks. This risk is incompatible with the safety concept of nuclear power units. Therefore, a relatively safer and more reliable oxygenation method is needed. Summary of the invention

[0007] The purpose of the present invention is to overcome the above-mentioned shortcomings of the prior art and provide a passive oxygen supplementation device and a control method thereof, wherein the device and the control method thereof can achieve safe and reliable oxygenation.

[0008] To achieve the above object, the present invention discloses a passive oxygen supply device, comprising a desalted water source, a condensate pump, a venturi tube, a condensate pump, an air supply filter, a low-pressure heater, a deaerator, a high-pressure heater and a steam generator;

[0009] The outlet of the desalted water source is divided into two routes, 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 filter 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 via the low-pressure heater, the deaerator and the high-pressure heater in sequence.

[0011] Furthermore, the outlet of the desalted water source is connected to the inlet of the condensate pump via the condenser water supply valve and the condenser in sequence.

[0012] Furthermore, the outlet of the desalted water source is connected to the inlet of the condensate pump via the oxygen supply main valve, the oxygen supply main pipe pressure sensor, the oxygen supply automatic regulating valve, the condensate oxygen supply flow meter, the Venturi tube, the oxygen supply check valve and the oxygen supply manual valve.

[0013] Furthermore, the air supply filter is connected to the inlet of the venturi tube via the air supply automatic regulating valve and the air supply manual regulating valve in sequence.

[0014] Furthermore, the outlet of the condensate pump is connected to the inlet of the steam generator via the fine treatment outlet oxygen meter, the condensate flow meter, the low-pressure heater, the deaerator inlet hydrogen conductivity meter, the deaerator inlet oxygen meter, the deaerator, the feed water pump, the feed water flow meter, the high-pressure heater, the steam generator inlet hydrogen conductivity meter and the steam generator inlet oxygen meter in sequence.

[0015] Furthermore, the deaerator is connected to a deaerator operation exhaust valve and a deaerator startup exhaust valve.

[0016] Furthermore, it also includes a control module, which is connected to the oxygen supply main pipe pressure sensor, the oxygen supply automatic regulating valve, the condensate oxygen supply flow meter, the air supply automatic regulating valve, the fine treatment outlet oxygen meter, the condensate flow meter, the deaerator inlet hydrogen conductivity meter, the deaerator inlet oxygen meter, the feed water flow meter, the steam generator inlet hydrogen conductivity meter, the steam generator inlet oxygen meter, the condensate pump and the feed water pump.

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

[0018] The present invention discloses a control method for a passive oxygen supplementation device, comprising the following steps:

[0019] 11) Open the oxygen supply main valve and oxygen supply manual valve, close the air supply automatic regulating valve and air supply manual regulating valve, and the oxygen supply automatic regulating valve is in the regulating state;

[0020] 12) Due to the negative pressure at the inlet of the condensate pump, the oxygenated desalted water in the desalted water source is sucked into the condensate pump;

[0021] 13) Adjust the opening of the oxygen supply automatic regulating valve to increase the flow rate of desalted water during the system's oxygenation conversion process, thereby increasing the oxygen content of the condensate system;

[0022] 14) When the flow rate measured by the condensate oxygen supply flowmeter exceeds the water supply of the system, open the manual air supply regulating valve, adjust the opening of the automatic air supply regulating valve, and use the Venturi tube self-priming air oxygen supply method to increase the oxygen supply of the system, ensuring that the oxygen content measured by the oxygen meter at the fine treatment outlet is close to the upper limit of oxygen content, so as to improve the oxygenation conversion efficiency of the system;

[0023] 15) After the system oxygenation conversion is completed, close the manual air supply regulating valve and the automatic air supply regulating valve, and control the oxygen supply automatic regulating valve to be in automatic regulation mode.

[0024] Furthermore, it also includes:

[0025] 21) During the oxidation operation of the system, the manual air supply regulating valve and the automatic air supply regulating valve are in the closed state, and the automatic oxygen supply regulating valve is in the automatic regulation mode;

[0026] 22) Keep the deaerator operation exhaust valve and the deaerator startup exhaust valve in the normal closed state;

[0027] 23) The water supply demand of the unit is first supplemented by the oxygen supply circuit, and the insufficient water is further supplemented by the condenser water supply valve;

[0028] 24) The system flow signal Q is calculated based on the data Q1 measured by the condensate flow meter and the data Q2 measured by the water supply flow meter, Q = K1Q1 + (1-K1)Q2, K1 is the oxygen supplement flow coefficient;

[0029] 25) Adjust the oxygen supply automatic regulating valve until the actual oxygen supply flow Q0 measured by the condensate water oxygen supply flow meter is consistent with the system flow signal Q; when the condensate water or feed water flow changes, the oxygen supply automatic regulating valve responds transiently;

[0030] 26) The oxygen-containing desalted water added by the oxygen supply automatic regulating valve is feed-forward regulated in proportion to the condensate and main feed water flow rates.

[0031] The present invention has the following beneficial effects:

[0032] During specific operation of the passive oxygen supply device and control method thereof described in the present invention, the oxygenation conversion process uses a Venturi self-priming air oxygenation method to increase the dissolved oxygen content in water, thereby ensuring the oxygenation conversion speed of the unit and achieving safe and reliable oxygenation.

[0033] Furthermore, in order to avoid the problem that the oxygen content in the feed water may fluctuate greatly or even exceed the upper limit due to overshoot of closed-loop control under different units and different load levels, the present invention adopts a feedforward proportional control mode, that is, the oxygen addition flow rate and the condensate flow rate maintain a certain ratio, which can respond synchronously with the changes in the condensate flow rate to avoid the lag of control. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] The accompanying drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the accompanying drawings:

[0035] Figure 1 It is a structural diagram of the present invention.

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

[0037] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0038] In the description of the present invention, it should be understood that the terms “include” and “comprises” indicate the presence of described features, wholes, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, wholes, steps, operations, elements, components and / or collections thereof.

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

[0040] It should be further understood that the term "and / or" used in the present specification and the appended claims refers to any combination of one or more of the associated listed items and all possible combinations, and includes these combinations. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in the present invention generally indicates that the associated objects are in an "or" relationship.

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

[0042] The word "if" as used herein may be interpreted as "at the time of" or "when" or "in response to determining" or "in response to detecting", depending on the context. Similarly, the phrases "if it is determined" or "if (stated condition or event) is detected" may be interpreted as "when it is determined" or "in response to determining" or "when detecting (stated condition or event)" or "in response to detecting (stated condition or event)", depending on the context.

[0043] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. The components of the embodiments of the present invention described and shown in the drawings here can usually be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0044] Various structural schematic diagrams of the embodiments disclosed in the present invention are shown in the accompanying drawings. These figures are not drawn to scale, and some details are magnified and some details may be omitted for the purpose of clear expression. The shapes of various regions and layers shown in the figures and the relative sizes and positional relationships therebetween are only exemplary, and may deviate in practice due to manufacturing tolerances or technical limitations, and those skilled in the art may additionally design regions / layers with different shapes, sizes, and relative positions according to actual needs.

[0045] refer to Figure 1 The passive oxygen supply device of the present invention comprises a desalted water source 1, a condenser water supply valve 2, a condenser 3, a condensate pump 4, an oxygen supply main valve 5, an oxygen supply main pipe pressure sensor 6, an oxygen supply automatic regulating valve 7, a condensate oxygen supply flowmeter 8, a venturi tube 9, an oxygen supply check valve 10, an oxygen supply manual valve 11, an air supply filter 12, an air supply automatic regulating valve 13, an air supply manual regulating valve 14, a fine 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 feed water pump 21, a feed water 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 routes, one of which is connected to the inlet of the condensate pump 4 via the condenser water supply valve 2 and the condenser 3 in sequence, and the other is connected to the inlet of the condensate pump 4 via the oxygen supply main valve 5, the oxygen supply main pipe pressure sensor 6, the oxygen supply automatic regulating valve 7, the condensate oxygen supply flowmeter 8, the Venturi tube 9, the oxygen supply check valve 10 and the oxygen supply manual valve 11 in sequence, and the air supply filter 12 is connected to the inlet of the Venturi tube 9 via the air supply automatic regulating valve 13 and the air supply manual regulating valve 14 in sequence.

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

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

[0049] The dissolved oxygen in the desalted water used for the daily condensate replenishment of the unit is used as the oxygen source. The daily replenishment of the unit is 0.5%-1.5%, and the actual dissolved oxygen in the desalted water exceeds 8000ppb, that is, the dissolved oxygen in the system water can be increased by 40-120ppb, which fully meets the requirements of the unit's oxidation operation conditions. Based on the above reality, the unit's replenishment water is used as an oxygen carrier, and desalted water containing dissolved oxygen is added to the condensate pump 4, which not only meets the system replenishment requirements, but also meets the unit's oxidation operation requirements.

[0050] The inlet main pipe of the condensate pump 4 is in a negative pressure state, so it is only necessary to connect the demineralized water to the inlet of the condensate pump 4 through a regulating valve to controllably supplement oxygen to the condensate system in a passive manner.

[0051] The oxygenation conversion process uses the Venturi tube 9 to self-absorb air to supplement oxygen to increase the dissolved oxygen content in the water and ensure the oxygenation conversion speed of the unit.

[0052] In order to avoid the problem of large fluctuations in feed water oxygen content or even exceeding the upper limit due to overshoot of closed-loop control under different units and different load levels, this scheme adopts a feedforward proportional control mode, that is, the oxygen addition flow and the condensate flow maintain a certain ratio, which can respond synchronously with the changes in the condensate flow to avoid control lag.

[0053] The control module 27 is a PLC or a power plant DCS. The control module 27 is connected to the oxygen supply main pipe pressure sensor 6, the oxygen supply automatic regulating valve, the condensate oxygen supply flowmeter 8, the air supply 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 feed water flowmeter 2, the steam generator inlet hydrogen conductivity meter 24, the steam generator inlet oxygen meter 25, the condensate pump 4 and the feed water pump 21.

[0054] The control method of the passive oxygen supplementation device of the present invention comprises the following steps:

[0055] 1) System oxygenation conversion process:

[0056] 11) During the oxygenation conversion process of the system, the oxygen supply main valve 5 and the oxygen supply manual valve 11 are opened, the air supply automatic regulating valve 13 and the air supply manual regulating valve 14 are closed, and the oxygen supply automatic regulating valve 7 is in the regulating state.

[0057] 12) Due to the negative pressure at the inlet of the condensate pump 4 , the oxygenated desalted water in the desalted water source 1 is sucked into the condensate pump 4 .

[0058] 13) Adjust the opening of the oxygen supply automatic regulating valve 7 to increase the flow rate of desalted water during the system's oxygenation conversion process, thereby increasing the oxygen content of the condensate system.

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

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

[0061] 2) Normal oxidation operation of the system:

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

[0063] 22) The deaerator operation exhaust valve 20-1 and the deaerator startup exhaust valve 20-2 are placed in a normally closed state, and are operated in a slightly open mode of 1-2 hours per week.

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

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

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

[0067] 26) Since the oxygen concentration of the desalted water in the oxygen supply device is much lower than that of pure oxygen or oxygen-enriched water, the oxygen-containing desalted water added by the oxygen supply automatic regulating valve 7 is feedforward-regulated in proportion to the condensate and main feed water flows, and the fluctuation of the system oxygen concentration is very low, generally 3-5pp.

[0068] 27) The above control processes are all implemented in the internal logic of the control module 27.

[0069] 3) System protection method:

[0070] 31) When the automatic air supply regulating valve 13 fails, the automatic air supply regulating valve 13 is manually opened to full open, and the oxygenation conversion is completed by manually adjusting the opening of the manual air supply regulating valve 14.

[0071] 32) Alarm signal: close the oxygen supply automatic regulating valve 7; when the pressure measured by the oxygen supply main pipe pressure sensor 6 is abnormal; the flow measured by the condensate oxygen supply flowmeter 8 is abnormal; the data measured by the fine treatment outlet oxygen meter 15, the deaerator inlet oxygen meter 19 and the steam generator inlet oxygen meter 25 are abnormal; the data measured by the deaerator inlet hydrogen conductivity meter 18 and the steam generator inlet hydrogen conductivity meter 24 are abnormal, an alarm signal is generated.

[0072] 33) Protection closing signal of oxygen supply automatic regulating valve 7: When the pressure measured by oxygen supply main pipe pressure sensor 6 is lower than the preset pressure lower limit; the flow rate measured by condensate oxygen supply flowmeter 8 is lower than the preset flow lower limit; the data measured by fine treatment outlet oxygen meter 15, deaerator inlet oxygen meter 19 and steam generator inlet oxygen meter 25 are abnormal; the data measured by deaerator inlet hydrogen conductivity meter 18 and steam generator inlet hydrogen conductivity meter 24 are abnormal, then the protection closing signal of oxygen supply automatic regulating valve 7 is generated.

[0073] 34) Automatic closing signal of the oxygen supply automatic regulating valve 7: When the data measured by the condensate oxygen supply flow meter 8 or the feed water flow meter 22 is lower than the preset flow lower limit; the condensate and feed water pumps 21 are all stopped; the unit shutdown signal is generated, the automatic closing signal of the oxygen supply automatic regulating valve 7 is generated.

[0074] 35) The above control processes are all implemented in the internal logic of the control module 27.

[0075] Those skilled in the art will readily appreciate other embodiments of the present invention after considering the specification and disclosure of the invention. This application is intended to cover any variations, uses or adaptations of the present invention that follow the general principles of the present invention and include common knowledge or customary techniques in the art that are not disclosed by the present invention. The specification and examples are to be considered exemplary only, and the true scope and spirit of the present invention are indicated by the following claims.

[0076] It should be understood that the present invention is not limited to the exact construction that has been described above and shown in the drawings and that various modifications and changes may be made without departing from the scope thereof. The scope of the present invention is limited only by the appended claims.

[0077] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any way. Any simple modification, change and equivalent structural change made to the above embodiment based on the technical essence of the present invention still falls within the protection scope of the technical solution of the present invention.

Claims

1. A passive oxygen supplementation device, characterized in that: It comprises a desalted water source (1), a condensate pump (4), a venturi tube (9), a condensate pump (4), an air supply filter (12), a low-pressure heater (17), a deaerator (20), a high-pressure heater (23) and a steam generator (26); 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), and the other is connected to the inlet of the condensate pump (4) via the venturi tube (9), and the air supply filter (12) is connected to the inlet of the venturi tube (9); The outlet of the condensate pump (4) is connected to the inlet of the steam generator (26) via the low-pressure heater (17), the deaerator (20) and the high-pressure heater (23) in sequence.

2. The passive oxygen supplementation device according to claim 1, characterized in that: The outlet of the desalted water source (1) is connected to the inlet of the condensate pump (4) via the condenser water supply valve (2) and the condenser (3) in sequence.

3. The passive oxygen supplementation device according to claim 2, characterized in that: The outlet of the desalted water source (1) is connected to the inlet of the condensate pump (4) via an oxygen supply main valve (5), an oxygen supply main pipe pressure sensor (6), an oxygen supply automatic regulating valve (7), a condensate oxygen supply flow meter (8), a venturi tube (9), an oxygen supply check valve (10) and an oxygen supply manual valve (11) in sequence.

4. The passive oxygen supplementation device according to claim 3, characterized in that: The air supply filter (12) is connected to the inlet of the venturi tube (9) via the air supply automatic regulating valve (13) and the air supply manual regulating valve (14) in sequence.

5. The passive oxygen supplementation device according to claim 4, characterized in that: The outlet of the condensate pump (4) is connected to the inlet of the steam generator (26) via the fine treatment outlet oxygen meter (15), the condensate flow meter (16), the low-pressure heater (17), the deaerator inlet hydrogen conductivity meter (18), the deaerator inlet oxygen meter (19), the deaerator (20), the feed water pump (21), the feed water flow meter (22), the high-pressure heater (23), the steam generator inlet hydrogen conductivity meter (24) and the steam generator inlet oxygen meter (25).

6. The passive oxygen supplementation device according to claim 5, characterized in that: The deaerator (20) is connected to a deaerator operation exhaust valve (20-1) and a deaerator startup exhaust valve (20-2).

7. The passive oxygen supplementation device according to claim 7, characterized in that: The invention also comprises a control module (27), wherein the control module (27) is connected to an oxygen supply main pipe pressure sensor (6), an oxygen supply automatic regulating valve, a condensate oxygen supply flow meter (8), an air supply automatic regulating valve (13), an oxygen meter at a fine treatment outlet (15), a condensate flow meter (16), a deaerator inlet hydrogen conductivity meter (18), a deaerator inlet oxygen meter (19), a feed water flow meter (2), a steam generator inlet hydrogen conductivity meter (24), a steam generator inlet oxygen meter (25), a condensate pump (4) and a feed water pump (21).

8. The passive oxygen supplementation device according to claim 7, characterized in that: The control module (27) is a PLC or a power plant DCS.

9. A control method for the passive oxygen supplementation device according to claim 6, characterized in that: The following steps are involved: 11) Open the oxygen supply main valve (5) and the oxygen supply manual valve (11), close the air supply automatic regulating valve (13) and the air supply manual regulating valve (14), and the oxygen supply automatic regulating valve (7) is in the regulating state; 12) Due to the negative pressure at the inlet of the condensate pump (4), the oxygenated desalted water in the desalted water source (1) is sucked into the condensate pump (4); 13) adjusting the opening of the oxygen supply automatic regulating valve (7) to increase the flow rate of desalted water during the system oxygenation conversion process, thereby increasing the oxygen content of the condensate system; 14) When the flow rate measured by the condensate oxygen supply flowmeter (8) exceeds the water supply amount of the system, the air supply manual regulating valve (14) is opened, the opening of the air supply automatic regulating valve (13) is adjusted, and the oxygen supply amount of the system is increased by using the venturi tube (9) to self-absorb air for oxygen supply, ensuring that the oxygen amount measured by the fine treatment outlet oxygen meter (15) is close to the upper limit of the oxygen amount, so as to improve the oxygenation conversion efficiency of the system; 15) After the oxygenation conversion of the system is completed, the manual air supply regulating valve (14) and the automatic air supply regulating valve (13) are closed, and the automatic oxygen supply regulating valve (7) is controlled to be in the automatic regulation mode.

10. The control method of the passive oxygen supplementation device according to claim 9, characterized in that: Also includes: 21) During the oxidation operation of the system, the air supply manual regulating valve (14) and the air supply automatic regulating valve (13) are in a closed state, and the oxygen supply automatic regulating valve (7) is in an automatic regulating mode; 22) The deaerator operation exhaust valve (20-1) and the deaerator startup exhaust valve (20-2) are in a normally closed state; 23) The water supply demand of the unit is first supplemented by the oxygen supply circuit, and the insufficient water is further supplemented by the condenser water supply valve (2); 24) The system flow signal Q is calculated based on the data Q1 measured by the condensate flow meter (16) and the data Q2 measured by the water supply flow meter (22), Q=K1Q1+(1-K1)Q2, K1 is the oxygen supplement flow coefficient; 25) adjusting the oxygen supply automatic regulating valve (7) until the actual oxygen supply flow Q0 measured by the condensate water oxygen supply flow meter (8) is consistent with the system flow signal Q; when the condensate water or feed water flow changes, the oxygen supply automatic regulating valve (7) responds transiently; 26) The oxygen-containing desalted water added by the oxygen supply automatic regulating valve (7) is feedforward regulated in proportion to the condensate and main feed water flows.

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