A cleaning method for a supercritical carbon dioxide power generation system

Abstract

The application discloses a cleaning method for a supercritical carbon dioxide power generation system, and belongs to the technical field of power generation system cleaning processes.The whole system is first divided into multiple independent loops, and a cleaning auxiliary system is built, then the pipeline is subjected to water pressure testing, and after passing the test, the pipeline is subjected to alkaline cleaning and acid cleaning in sequence, then a passivation agent is added to form a passivation film, finally, a pressurized gas is introduced to empty the residual liquid in the system, and then the pipeline is subjected to pressurized water flushing and emptying.The system is divided into multiple independent cleaning loops, fine cleaning is realized, various pollutants are effectively removed, and sensitive equipment is protected.The alkaline cleaning, acid cleaning and passivation process are performed in steps, not only the pipeline is thoroughly cleaned, but also a uniform and dense passivation film is formed, secondary corrosion can be prevented for a long time, and the cleanliness, corrosion resistance and long-term operation stability of the system are significantly improved.

Description

Technical Field

[0001] This invention relates to the field of power generation system cleaning technology, and more specifically to a cleaning method for supercritical carbon dioxide power generation systems. Background Technology

[0002] The steel industry is a key high-energy-consuming and high-emission industry, and its production process generates a large amount of medium-temperature waste heat. Supercritical carbon dioxide power generation technology, also known as supercarbon power generation, is an innovative thermoelectric conversion solution specifically designed for steel plants and similar industries that have abundant total heat sources, wide temperature ranges, and strong temperature fluctuations, thus utilizing waste heat. The advantage of this technology lies in its significantly improved efficiency in utilizing medium-temperature waste heat, effectively compensating for the shortcomings of traditional power generation methods, such as limited power generation efficiency and insufficient equipment flexibility under conditions of large temperature ranges and flow fluctuations.

[0003] However, this technology has extremely stringent requirements for system cleanliness, explicitly stipulating that no impurities larger than 1 micrometer can exist in the system. Existing conventional cleaning methods are unable to meet this ultra-high requirement. Residual oxides, welding slag, and other contaminants in the system pipelines can lead to decreased system efficiency or even equipment damage, seriously affecting the system's safety and economy. This invention proposes a new solution to address these problems. Summary of the Invention

[0004] To overcome at least one of the aforementioned drawbacks, this invention provides a cleaning method for supercritical carbon dioxide power generation systems. The objective of this invention can be achieved by employing the following technical solution: This application provides a cleaning method for a supercritical carbon dioxide power generation system, the steps of which include: The supercritical carbon dioxide power generation system is divided and isolated into multiple independent cleaning loops, and a demineralized water supply system, a steam supply system, a power supply system and a wastewater discharge system are established. Pressure tests were conducted on the high-temperature and high-pressure pipelines within the system. After passing the pressure test, the heated and pressurized alkaline cleaning solution is pumped into the pipeline to be cleaned for circulation cleaning to remove grease, oil stains, organic contaminants and some acidic precipitates from the pipeline to be cleaned. After completing the alkaline washing step, the pickling solution is pumped into the pipeline to be cleaned for circulation cleaning to remove metal oxides and welding slag contaminants in the pipeline to be cleaned. Then, a passivating agent is added for passivation treatment to form a passivation film on the metal surface. After the pickling and passivation steps are completed, pressurized gas is introduced to purge the liquid in the system, followed by pressurized rinsing with water, and finally the water in the system is drained.

[0005] In one possible implementation, the number of independent loops formed by the segmentation is not less than 100.

[0006] In one possible implementation, the brine supply system is used for continuous water supply and ensures that the water flow rate of the demineralized water pump can reach the preset pressure and requirements.

[0007] In one possible implementation, the steam supply system is used to provide steam at a preset pressure and a preset temperature.

[0008] In one possible implementation, the wastewater discharge system is used to promptly discharge wastewater generated during the cleaning process.

[0009] In one possible implementation, after the alkaline washing step is completed, the rinsing drainage needs to be sampled and tested. Once the test is passed, the alkaline washing cleaning of that circuit is stopped.

[0010] In one possible implementation, during the pickling and passivation step, a specific passivating agent needs to be added to the system after pickling for passivation treatment.

[0011] In one possible implementation, during the pickling and passivation step, the passivation effect needs to be tested after the passivation treatment is completed, and the passivation solution is discharged after passing the test.

[0012] In one possible implementation, in both the alkaline washing step and the acid washing and passivation step, the cleaning solution must be filtered by a filtration device before entering the pipeline to be cleaned for circulation.

[0013] In one possible implementation, the cleaning method is applicable to supercritical carbon dioxide power generation systems with medium-temperature waste heat recovery in the steel industry. After cleaning, there are no impurities larger than 1μm in the pipe, no secondary corrosion or pitting, and the passivation film is uniform and intact.

[0014] The beneficial technical effects of this invention are as follows: According to this disclosure, the cleaning method for a supercritical carbon dioxide power generation system successfully overcomes the problem that overall system cleaning is difficult to cover all pipelines and easily damages precision equipment by effectively dividing and isolating the large supercritical carbon dioxide power generation system into multiple independent cleaning loops. The loop-by-loop and step-by-step cleaning method not only ensures sufficient circulation and contact of the cleaning agent, but also thoroughly removes grease, oil stains, organic pollutants, metal oxides, welding slag, and other impurities from each pipeline. It also effectively isolates and protects sensitive equipment in the system that should not come into contact with the cleaning solution, avoiding damage or contamination risks to critical equipment during the cleaning process, and ensuring the safety of the system's core components. After system isolation, alkaline washing, acid washing, and passivation treatment are performed sequentially. The alkaline washing step effectively removes grease and organic deposits that affect heat exchange efficiency. The subsequent pickling step effectively removed hard contaminants such as metal oxides and welding slag. The final passivation treatment generated a uniform, dense, and complete passivation film in situ on the thoroughly cleaned metal surface. This passivation film can effectively prevent secondary corrosion and pitting of the metal substrate in subsequent operation, improving the system's corrosion resistance and long-term operational stability. After cleaning, the inner surface of the metal reaches a highly clean state with virtually no residual contaminants, meeting the requirements of supercritical carbon dioxide power generation technology for pipeline cleanliness. This solves the core technical bottleneck of extremely high cleanliness treatment inside the pipeline, which restricts the performance, efficiency, and reliability of supercritical carbon dioxide power generation systems. It ensures that the system has optimal thermal performance and transmission efficiency from the initial stage of commissioning, and the stable passivation film provides continuous protection for the long-term, safe, and stable operation of the system. Attached Figure Description

[0015] The following are given by way of example and without limitation in the accompanying drawings: Figure 1 The main process flow diagram of the cleaning method of the present invention is shown; Figure 2 A process flow diagram of the alkaline washing step in the cleaning method of the present invention is shown; Figure 3 A process flow diagram of the acid washing step in the cleaning method of the present invention is shown. Detailed Implementation

[0016] In the following detailed disclosure, these embodiments are fully described with reference to the accompanying drawings. In order to enable those skilled in the art to understand and clarify the technical solution of the present invention more clearly, the embodiments described below are not limited thereto. The present invention will be further described in detail below with reference to the embodiments and the accompanying drawings.

[0017] In this invention, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance; the term "multiple" refers to two or more unless otherwise explicitly defined. The terms "install," "connect," "link," and "fix" should be interpreted broadly. For example, "connect" can be a fixed connection, a detachable connection, or an integral connection; "link" can be a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0018] In the description of this invention, it should be understood that the terms "upper," "lower," "left," "right," "front," "rear," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or unit referred to must have a specific orientation or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0019] This application provides a cleaning method for supercritical carbon dioxide power generation systems, such as... Figures 1-3 As shown, the steps include: dividing and isolating the supercritical carbon dioxide power generation system into multiple independent cleaning loops, establishing a demineralized water supply system, a steam supply system, a power supply system, and a wastewater discharge system; conducting pressure tests on the high-temperature and high-pressure pipelines within the system; after passing the pressure test, pumping the heated and pressurized alkaline cleaning solution into the pipelines to be cleaned for circulation cleaning to remove grease, oil stains, organic contaminants, and some acidic precipitates from the pipelines to be cleaned; after completing the alkaline cleaning step, pumping the acid cleaning solution into the pipelines to be cleaned for circulation cleaning to remove metal oxides and welding slag contaminants from the pipelines to be cleaned, then adding a passivating agent for passivation treatment to form a passivation film on the metal surface; after completing the acid cleaning and passivation step, introducing pressurized gas to drain the liquid from the system, then introducing water for pressurized flushing, and finally draining the water from the system.

[0020] The cleaning method for a supercritical carbon dioxide power generation system provided in this embodiment overcomes the difficulty of covering all pipelines and the risk of damaging precision equipment when cleaning the entire system, by effectively dividing and isolating the large supercritical carbon dioxide power generation system into multiple independent cleaning loops. The loop-by-loop, step-by-step cleaning method not only ensures sufficient circulation and contact of the cleaning agent, thoroughly removing grease, oil, organic contaminants, metal oxides, welding slag, and other impurities from each pipeline, but also effectively isolates and protects sensitive equipment in the system that should not come into contact with the cleaning solution, avoiding damage or contamination risks to critical equipment during the cleaning process and ensuring the safety of the system's core components. After system isolation, alkaline washing, acid washing, and passivation treatment are performed sequentially. The alkaline washing step effectively removes grease and organic deposits that affect heat exchange efficiency, followed by acid washing... The process effectively removes hard contaminants such as metal oxides and welding slag. The final passivation treatment generates a uniform, dense, and complete passivation film in situ on the thoroughly cleaned metal surface. This passivation film can effectively prevent secondary corrosion and pitting of the metal substrate during subsequent operation, improving the system's corrosion resistance and long-term operational stability. After cleaning, the inner surface of the metal reaches a highly clean state with virtually no residual contaminants, meeting the requirements of supercritical carbon dioxide power generation technology for pipeline cleanliness. This solves the core technical bottleneck of extremely high cleanliness treatment inside the pipeline, which restricts the performance, efficiency, and reliability of supercritical carbon dioxide power generation systems. It ensures that the system has optimal thermal performance and transmission efficiency from the initial stage of commissioning, and the stable passivation film provides continuous protection for the long-term, safe, and stable operation of the system.

[0021] In one possible implementation, the number of independent loops formed by the segmentation is not less than 100.

[0022] Dividing the system into a sufficient number of independent loops enables precise and comprehensive cleaning of the supercritical carbon dioxide power generation system. Each independent loop can be cleaned specifically to ensure that the cleaning agent fully contacts the inner wall of the pipeline, thoroughly removing various pollutants. At the same time, it avoids cross-contamination between different loops, greatly improving cleaning efficiency and cleanliness. The loop-based cleaning mode can also accurately protect sensitive equipment in the system and reduce the risk of damage to core components during cleaning operations.

[0023] In one possible implementation, the brine supply system is used for continuous water supply and ensures that the water flow rate of the demineralized water pump can reach the preset pressure and requirements.

[0024] The brine supply system continuously provides sufficient water for the cleaning process, ensuring that the demineralized water pump always maintains the preset pressure and flow requirements, providing sufficient power for each stage such as alkaline washing, acid washing, passivation and rinsing, and ensuring that the cleaning agent circulates efficiently in the pipeline and fully contacts the pipe wall to thoroughly remove various pollutants.

[0025] Understandably, stable pressure and flow output can avoid problems such as incomplete cleaning and chemical residues caused by insufficient water supply or pressure fluctuations, effectively improving cleaning efficiency and cleanliness, and laying a solid foundation for the stable operation of the system in the future.

[0026] In one possible implementation, the steam supply system is used to provide steam at a preset pressure and a preset temperature.

[0027] The steam supply system continuously provides steam that meets preset parameters, ensuring stable heat and pressure for the cleaning process. This ensures that the cleaning solutions in alkaline washing, acid washing, and other processes are always maintained within a suitable temperature range, enhancing the chemical reaction efficiency between the cleaning agents and contaminants on the pipe wall, and accelerating the removal and dissolution of impurities such as grease and oxides.

[0028] Understandably, precise and controllable steam parameters can avoid the problem of unstable cleaning results caused by temperature or pressure fluctuations, ensure the consistency of cleaning quality in each loop, and greatly improve cleaning efficiency.

[0029] In one possible implementation, the wastewater discharge system is used to promptly discharge wastewater generated during the cleaning process.

[0030] The wastewater discharge system promptly discharges the wastewater generated during the cleaning process, preventing the accumulation and backflow of pollutant-containing cleaning waste liquid within the system, preventing the removed impurities from re-adhering to the pipe wall and causing secondary pollution, and ensuring the stability of the cleaning effect.

[0031] Understandably, continuous wastewater discharge can maintain the continuity of the cleaning process, without interrupting operations due to waste liquid accumulation, effectively improving overall cleaning efficiency. Standardized wastewater discharge avoids pollution of the environment and meets environmental protection requirements.

[0032] In one possible implementation, such as Figure 2 As shown, after the alkaline washing step is completed, the rinsing drainage needs to be sampled and tested. Once the test is passed, the alkaline washing cleaning of this circuit will be stopped.

[0033] After the alkaline washing step is completed, the flushing drainage is sampled and tested. The sampling and testing can accurately determine whether the grease, organic pollutants and acidic deposits in the pipeline have been completely removed. This avoids the pipeline from directly entering the subsequent process due to substandard cleaning, which would cause residual pollutants to affect the pickling and passivation effect or even damage the system equipment. The alkaline washing of the circuit is stopped only after the test is qualified, which can ensure that each cleaning circuit meets the preset cleanliness standard.

[0034] In one possible implementation, such as Figure 3 As shown, in the pickling and passivation step, after pickling, a specific passivating agent needs to be added to the system for passivation treatment.

[0035] After pickling, the oxides, rust, and other dirt on the metal surface are removed, exposing a fresh metal substrate with high activity. If directly exposed to air, it is very easy for secondary oxidation and corrosion to occur quickly, affecting the service life and operating performance of the equipment. At this time, adding a specific passivating agent for passivation treatment can generate a thin and dense passivation film on the metal surface, effectively isolating the metal substrate from the external corrosive medium, greatly improving its corrosion resistance, and providing a reliable guarantee for the long-term stable operation of the equipment.

[0036] The selection of passivation agents must be precisely matched according to the metal material, equipment operating conditions, and corrosion prevention requirements. Common passivation agents include those containing chromates, nitrates, phosphates, hydrogen peroxide, and acetone oxime. For example, stainless steel is usually passivated using passivation solutions containing chromic acid or nitric acid, which can form a highly stable passivation film; equipment such as boilers can be passivated using hydrogen peroxide or acetone oxime, which is not only environmentally friendly and pollution-free, but also generates a uniform and dense protective film on the metal surface.

[0037] After pickling, the pickling solution in the system must be completely drained, and the metal surface must be repeatedly rinsed with clean water to ensure no acidic residue remains. Then, according to process requirements, a specific passivating agent is added to the system to prepare a passivating solution of appropriate concentration. The circulation pump is started to ensure continuous circulation of the passivating solution within the system, guaranteeing that all metal surfaces are fully in contact with the passivating agent. Simultaneously, parameters such as passivation temperature, time, and pH value are strictly controlled to ensure the quality of the passivation film formation. After passivation is complete, the passivating solution is drained promptly, and the system is rinsed with plenty of clean water to remove any residual passivating agent. Finally, the metal surface is thoroughly dried using compressed air or a drying device to prevent moisture residue from causing corrosion.

[0038] In one possible implementation, such as Figure 3 As shown, in the pickling and passivation step, the passivation effect needs to be tested after the passivation treatment is completed, and the passivation solution is discharged after passing the test.

[0039] The passivation process involves an effectiveness test before the passivation solution is drained. This test accurately determines whether a uniform and dense passivation film has formed on the metal surface, preventing substandard passivation from directly entering subsequent processes and causing secondary corrosion, pitting, and other problems during operation, which could affect the system's lifespan and operational stability. Draining the passivation solution only after passing the test ensures that each cleaning loop meets the preset corrosion prevention standards, effectively reducing later maintenance costs and the risk of failure.

[0040] In one possible implementation, such as Figure 3 As shown, in both the alkaline washing and acid pickling passivation steps, the cleaning solution must be filtered by a filtration device before entering the pipeline to be cleaned for circulation.

[0041] In the alkaline washing and acid pickling passivation steps of the supercritical carbon dioxide power generation system, the cleaning solution is filtered by a filter device before entering the pipeline to be cleaned for circulation. The filter device can effectively intercept impurities such as grease, oxides, and welding slag that are peeled off from the pipe wall during the cleaning process, preventing these impurities from flowing back into the pipeline with the cleaning solution, causing secondary pollution or clogging of the flow channel. This ensures that the cleaning solution always remains clean, enabling it to continuously and efficiently react with contaminants on the pipe wall, greatly improving the thoroughness and uniformity of the cleaning, and creating good surface conditions for the subsequent formation of the passivation film.

[0042] The filtration device not only improves the cleaning effect but also plays an important role in protecting the system equipment. If no filtration device is installed during the cleaning process, the stripped impurities may enter precision components such as pumps and valves with the cleaning solution, causing wear, jamming and other malfunctions, affecting the service life and operating performance of the equipment. By intercepting the impurities, the damage to the equipment is effectively reduced, and the risk of equipment failure during the cleaning process is lowered.

[0043] The inclusion of a filtration device further enhances cleaning efficiency. The clean cleaning solution dissolves and removes contaminants more quickly, shortening cleaning time and preventing repeated cleaning due to impurity backflow. This reduces the consumption of cleaning agents and wastewater generation, lowering cleaning costs. Simultaneously, the real-time filtration function of the device ensures the cleaning solution maintains a stable concentration and performance, guaranteeing consistent cleaning results across all cleaning loops and improving the standardization of the overall cleaning operation.

[0044] In one possible implementation, the cleaning method is applicable to supercritical carbon dioxide power generation systems with medium-temperature waste heat recovery in the steel industry. After cleaning, there are no impurities larger than 1μm in the pipe, no secondary corrosion or pitting, and the passivation film is uniform and intact.

[0045] The cleaning method provided in this embodiment is applicable to supercritical carbon dioxide power generation systems with waste heat recovery in the steel industry. Through refined cleaning in separate loops and multi-stage filtration, it achieves ultimate cleanliness of the inner surface of the pipeline. The synergistic effect of alkaline washing and acid passivation removes contaminants such as grease, organic matter, metal oxides, and welding slag. In conjunction with passivation agents, a continuous, dense, and defect-free protective film is formed in situ on the metal substrate, effectively preventing the intrusion of corrosive media. After cleaning, there are no particles larger than 1μm remaining in the pipeline, eliminating the risk of secondary rust and pitting corrosion. This ensures that the system can operate stably for a long time under high purity and high pressure conditions, meeting the dual requirements of extreme cleanliness and corrosion resistance.

[0046] The cleaning method of this application mainly includes steps such as system preparation, water pressure test, alkaline washing, acid pickling and passivation.

[0047] The purpose of system preparation is primarily to prepare for the cleaning of the supercritical carbon dioxide power generation system. System isolation is a key focus, effectively dividing the entire system into multiple parts. These mainly include demineralized water supply, steam supply, power supply, wastewater discharge, and system isolation. This cleaning method establishes a demineralized water system, ensuring a continuous water supply during the cleaning process and guaranteeing that the demineralized water pump flow rate meets the required pressure and operating conditions. A steam system is also established, ensuring that the steam system reaches a fixed pressure and temperature to meet system requirements during cleaning. A wastewater system is also established, allowing for timely discharge of wastewater during the cleaning process. The most important aspect of this cleaning method is system isolation, dividing the system into hundreds of individual small loops for separate cleaning, which also provides protection for precision equipment.

[0048] The main purpose of water pressure testing is to conduct pipeline pressure tests on certain high-temperature and high-pressure pipelines in supercritical carbon dioxide power generation systems. Only after the pressure test is completed can specific cleaning work be carried out.

[0049] The purpose of alkaline washing is to remove grease, oil, organic contaminants, and some acidic precipitates from the system's pipelines. Temporary pipelines and corresponding filtration devices are installed before the water enters the system. The alkaline washing process mainly includes the following steps: First, the cleaning solution enters the temporary pipelines and containers. After being heated and pressurized to a certain pressure and temperature by pumps and other devices in the temporary pipelines, it enters the filtration device, then enters the specific pipeline to be cleaned, and finally exits through the corresponding temporary pipes to a specific wastewater collection device. This completes the first flush of the system. After the flushing drainage sample passes inspection, the alkaline washing cleaning of this loop is complete.

[0050] The purpose of pickling and passivation is to remove metal oxides, welding slag, and other substances from the system pipelines and form an effective passivation film. This step is similar to alkaline cleaning, but the chemicals used are significantly different. After pickling, the system is passivated. After chemical cleaning, a specific chemical is added for further passivation. Once the passivation test is passed, the passivation solution is drained. Subsequently, gas at a specific temperature and pressure is introduced into the system to purge the passivation liquid. Then, water at a specific pressure is introduced for pressurized flushing, finally draining the water from the system.

[0051] After cleaning, the metal surface is clean, with virtually no residual oxides or welding slag, and there should be no secondary corrosion or pitting. The passivation film is uniform and intact. The implementation of this invention patent not only greatly solves the problem of high cleanliness requirements in pipelines of supercritical carbon dioxide power generation systems or similar systems, but also avoids the hidden dangers of cleaning damage and impurity contamination to critical equipment within the system.

[0052] In the description of this specification, the terms "one embodiment," "some embodiments," "specific embodiment," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which 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. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0053] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

[0054] In view of the detailed description above, these and other changes can be made to these embodiments, and this written description includes embodiments of the best mode that disclose the invention. The patent scope of the invention is defined by the claims, which are not limited by this disclosure. The scope of protection of the invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the invention disclosed herein, based on the technical solutions and concepts of the invention, are within the scope of protection of the invention.

Claims

1. A cleaning method for a supercritical carbon dioxide power generation system, characterized in that the steps include... include: The supercritical carbon dioxide power generation system is divided and isolated into multiple independent cleaning loops, and a demineralized water supply system, a steam supply system, a power supply system and a wastewater discharge system are established. Pressure tests were conducted on the high-temperature and high-pressure pipelines within the system. After passing the pressure test, the heated and pressurized alkaline cleaning solution is pumped into the pipeline to be cleaned for circulation cleaning to remove grease, oil stains, organic contaminants and some acidic precipitates from the pipeline to be cleaned. After completing the alkaline washing step, the pickling solution is pumped into the pipeline to be cleaned for circulation cleaning to remove metal oxides and welding slag contaminants in the pipeline to be cleaned. Then, a passivating agent is added for passivation treatment to form a passivation film on the metal surface. After the pickling and passivation steps are completed, pressurized gas is introduced to purge the liquid in the system, followed by pressurized rinsing with water, and finally the water in the system is drained.

2. The cleaning method for a supercritical carbon dioxide power generation system according to claim 1, characterized in that, The number of independent loops formed by the segmentation shall not be less than 100.

3. The cleaning method for a supercritical carbon dioxide power generation system according to claim 1, characterized in that, The brine supply system is used for continuous water supply and ensures that the water flow rate of the demineralized water pump can reach the preset pressure and requirements.

4. The cleaning method for a supercritical carbon dioxide power generation system according to claim 1, characterized in that, The steam supply system is used to provide steam at a preset pressure and preset temperature.

5. The cleaning method for a supercritical carbon dioxide power generation system according to claim 1, characterized in that, The wastewater discharge system is used to promptly discharge wastewater generated during the cleaning process.

6. The cleaning method for a supercritical carbon dioxide power generation system according to claim 1, characterized in that, After the alkaline washing step is completed, the rinsing drainage needs to be sampled and tested. Once the test is passed, the alkaline washing cleaning of this circuit will be stopped.

7. The cleaning method for a supercritical carbon dioxide power generation system according to claim 1, characterized in that, In the pickling and passivation step, after pickling, a specific passivating agent needs to be added to the system for passivation treatment.

8. The cleaning method for a supercritical carbon dioxide power generation system according to claim 1, characterized in that, In the pickling and passivation step, the passivation effect needs to be tested after the passivation treatment is completed, and the passivation solution is discharged after passing the test.

9. The cleaning method for a supercritical carbon dioxide power generation system according to claim 1, characterized in that, In both the alkaline washing and acid pickling passivation steps, the cleaning solution must be filtered by a filtration device before entering the pipeline to be cleaned for circulation.

10. The cleaning method for a supercritical carbon dioxide power generation system according to claim 1, characterized in that, The cleaning method described herein is applicable to supercritical carbon dioxide power generation systems with medium-temperature waste heat recovery in the steel industry. After cleaning, there are no impurities larger than 1μm in the pipe, no secondary corrosion or pitting, and the passivation film is uniform and intact.

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