Supercritical carbon dioxide brayton cycle working fluid purification system

Abstract

The application discloses a supercritical carbon dioxide Brayton cycle working medium purification system, which comprises a first filtering unit, a catalytic conversion unit and a parallel adsorption unit group; the inlet end of the first filtering unit is connected with the high-temperature side inlet front pipeline of a regenerator in a supercritical carbon dioxide Brayton cycle system in communication and is configured to intercept solid particle impurities in the cycle working medium; the inlet end of the catalytic conversion unit is connected with the outlet end of the first filtering unit in communication and is configured to catalytically convert carbon monoxide contained in the cycle working medium treated by the first filtering unit into carbon dioxide; the parallel adsorption unit group comprises at least two parallel arranged adsorption units, the inlet end of each adsorption unit is connected with the outlet end of the catalytic conversion unit in communication, the outlet end of each adsorption unit is connected with the rear pipeline of a cooler in the supercritical carbon dioxide Brayton cycle system in communication, and each adsorption unit is configured to remove residual oxygen, water vapor and carbon monoxide in the cycle working medium treated by the catalytic conversion unit.

Description

Technical Field

[0001] This application belongs to the technical field of working fluid purification systems, specifically relating to a supercritical carbon dioxide Brayton cycle working fluid purification system. Background Technology

[0002] Supercritical carbon dioxide Brayton cycle, as a new generation of high-efficiency thermodynamic cycle technology, has shown broad application prospects in nuclear energy, solar thermal power generation, and industrial waste heat recovery due to its advantages such as high cycle efficiency, compact equipment structure, and low environmental impact. This cycle uses supercritical carbon dioxide as the working fluid and achieves energy conversion through turbine expansion. However, the purity of the working fluid directly affects the long-term stability, equipment lifespan, and safety of the system.

[0003] In supercritical carbon dioxide Brayton cycle systems, long-term flow of the working fluid can lead to wear on the inner walls of equipment and the shedding of corrosion products, forming solid impurities such as metal particles and oxide debris. If these particles enter critical components such as turbines and regenerators, they can cause flow channel blockage, impeller wear, or even system leaks, significantly reducing equipment reliability. Simultaneously, the working fluid may undergo thermal decomposition or chemical reactions under high temperatures and the action of catalysts to generate carbon monoxide. Carbon monoxide not only acts as an "inert diluent" for the circulating working fluid, reducing circulation efficiency, but it can also accumulate in dead zones of the equipment, mixing with oxygen to form explosive gas mixtures, posing safety hazards. Furthermore, inadequate sealing of the circulation system or the introduction of oxygen and water vapor during the preparation of the working fluid can exacerbate the oxidation and corrosion of metal components, while water vapor can form acidic substances (such as carbonic acid), further accelerating equipment corrosion and reducing the chemical stability of the working fluid. Summary of the Invention

[0004] In view of this, this application provides a supercritical carbon dioxide Brayton cycle working fluid purification system, the main purpose of which is to purify carbon monoxide, oxygen, water vapor and solid particulate impurities in the circulating working fluid.

[0005] To achieve the above objectives, this application mainly provides the following technical solutions:

[0006] This application provides a supercritical carbon dioxide Brayton cycle working fluid purification system, comprising:

[0007] The first filtration unit is connected to the high-temperature side inlet front pipeline of the regenerator in the supercritical carbon dioxide Brayton cycle system, and is configured to intercept solid particulate impurities in the circulating working fluid.

[0008] A catalytic conversion unit, wherein the inlet end of the catalytic conversion unit is connected to the outlet end of the first filtration unit, and the catalytic conversion unit is provided with a catalyst bed, configured to catalytically convert carbon monoxide contained in the circulating working fluid after being treated by the first filtration unit into carbon dioxide;

[0009] The parallel adsorption unit group includes at least two adsorption units arranged in parallel. The inlet end of each adsorption unit is connected to the outlet end of the catalytic conversion unit, and the outlet end of each adsorption unit is connected to the rear end pipeline of the cooler in the supercritical carbon dioxide Brayton cycle system. The adsorption unit is provided with an adsorbent bed, configured to remove residual oxygen, water vapor and carbon monoxide in the circulating working fluid after being treated by the catalytic conversion unit.

[0010] Optionally, a flow regulating valve is provided on the connecting pipeline between the outlet end of the first filter unit and the high-temperature side inlet of the regenerator. The flow regulating valve is configured to adjust the flow rate of the purification branch to 5% of the main circuit gas filling amount.

[0011] The main loop gas loading amount is the total mass flow rate of the circulating working fluid when the supercritical carbon dioxide Brayton cycle system is running stably.

[0012] Optionally, a second filter unit is provided on the connecting pipe between the outlet end of the parallel adsorption unit group and the rear end pipe of the cooler. The second filter unit is configured to intercept adsorbent particles or catalytic reaction byproducts remaining in the circulating working fluid after being treated by the parallel adsorption unit group.

[0013] Optionally, the supercritical carbon dioxide Brayton cycle working fluid purification system further includes:

[0014] The heat exchange unit includes a first flow channel and a second flow channel. The inlet end of the first flow channel is connected to the outlet end of the first filter unit, and the outlet end of the first flow channel is connected to the inlet end of the catalytic conversion unit. The heat exchange unit is configured to allow the circulating working fluid in the first flow channel to exchange heat with the fluid in the second flow channel in order to cool the circulating working fluid after it has been treated by the first filter unit.

[0015] Optionally, the outlet end of the catalytic conversion unit is connected to the inlet end of the second flow channel of the heat exchange unit, and the outlet end of the second flow channel is connected to the inlet end of the parallel adsorption unit group. The heat exchange unit is configured to allow the circulating working fluid in the second flow channel, which has been treated by the catalytic conversion unit, to perform countercurrent heat exchange with the circulating working fluid in the first flow channel, so as to reduce the temperature of the circulating working fluid in the first flow channel to the threshold temperature of the carbon monoxide conversion reaction in the catalytic conversion unit.

[0016] Optionally, a cooling unit is provided on the connecting pipe between the outlet end of the second flow channel and the inlet end of the parallel adsorption unit group. The cooling unit is configured to cool the circulating working fluid after heat exchange by the heat exchange unit.

[0017] Optionally, at least two adsorption units arranged in parallel include a first adsorption unit and a second adsorption unit. The first adsorption unit is equipped with a first regeneration heating unit, and the second adsorption unit is equipped with a second regeneration heating unit. The first regeneration heating unit and the second regeneration heating unit are used to regenerate and heat the first adsorption unit and the second adsorption unit, respectively.

[0018] Optionally, the supercritical carbon dioxide Brayton cycle working fluid purification system further includes:

[0019] The control system, configured to execute adsorption-regeneration switching logic, includes:

[0020] When the first adsorption unit is in the adsorption state, the second adsorption unit simultaneously enters the regeneration state, the second regeneration heating unit starts and supplies regeneration gas to the second adsorption unit;

[0021] When the second adsorption unit reaches the preset regeneration level, the control system switches the first adsorption unit into the regeneration state and simultaneously switches the second adsorption unit into the adsorption state, thereby achieving continuous purification of the circulating working fluid through alternating cycles.

[0022] Optionally, the adsorption-regeneration switching logic further includes:

[0023] The circulating working fluid after being processed by the parallel adsorption unit group is sampled and analyzed, and the corresponding adsorption unit is determined to have reached the preset regeneration degree based on the sampling and analysis results, so as to trigger the switching of adsorption-regeneration state.

[0024] Optionally, the catalytic conversion unit and at least two adsorption units constituting the parallel adsorption unit group are all pressure vessels, and each is equipped with a safety valve.

[0025] By employing the above technical solution, this application has at least the following beneficial effects:

[0026] The supercritical carbon dioxide Brayton cycle working fluid purification system provided in the embodiments of this application forms a multi-stage purification process by setting up a first filtration unit, a catalytic conversion unit and a parallel adsorption unit. It systematically solves the pollution problems of solid particulate impurities, corrosive gases (such as oxygen and water vapor) and harmful components (such as carbon monoxide) in the circulating working fluid, and achieves multiple goals of equipment protection, safety improvement and efficiency optimization, thereby ensuring that the supercritical carbon dioxide Brayton cycle system can operate safely and stably. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the structure of a supercritical carbon dioxide Brayton cycle working fluid purification system according to an optional embodiment of this application;

[0028] Figure 2 This is a schematic diagram of the structure of a supercritical carbon dioxide Brayton cycle system according to an optional embodiment of this application.

[0029] The reference numerals in the attached figures are as follows:

[0030] 1. First filtration unit; 2. Catalytic conversion unit; 3. Heat exchange end unit; 4. Cooling unit; 5. First adsorption unit; 6. Second adsorption unit; 7. First regeneration and reheating unit; 8. Second regeneration and heating unit; 9. Second filtration unit; 10. Purification branch; 11. Flow regulating valve; 12. Main circuit; 13. Regenerator; 14. Cooler. Detailed Implementation

[0031] In the description of this application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element 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 application.

[0032] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0033] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0034] The preferred embodiments of this application are described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are for illustration and explanation only and are not intended to limit this application.

[0035] See Figure 1 and Figure 2 As shown in the embodiments of this application, a supercritical carbon dioxide Brayton cycle working fluid purification system is provided, including a first filtration unit 1, a catalytic conversion unit 2, and a parallel adsorption unit group; the inlet end of the first filtration unit 1 is connected to the front end pipeline of the high-temperature side inlet of the regenerator 13 in the supercritical carbon dioxide Brayton cycle system, and is configured to intercept solid particulate impurities in the circulating working fluid; the inlet end of the catalytic conversion unit 2 is connected to the outlet end of the first filtration unit 1, and the catalytic conversion unit 2 is provided with a catalyst bed, and is configured to catalytically convert carbon monoxide contained in the circulating working fluid after treatment by the first filtration unit 1 into carbon dioxide; the parallel adsorption unit group includes at least two adsorption units arranged in parallel, the inlet end of each adsorption unit is connected to the outlet end of the catalytic conversion unit 2, and the outlet end of each adsorption unit is connected to the rear end pipeline of the cooler 14 in the supercritical carbon dioxide Brayton cycle system, and the adsorption unit is provided with an adsorbent bed, and is configured to remove residual oxygen, water vapor, and carbon monoxide in the circulating working fluid after treatment by the catalytic conversion unit 2.

[0036] The supercritical carbon dioxide Brayton cycle working fluid purification system provided in this embodiment has a first filtration unit 1 as a primary purification stage, which is responsible for intercepting mechanical impurities (such as solid particulate impurities) in the circulating working fluid; a catalytic conversion unit 2 as an intermediate treatment stage, which eliminates harmful gas components (such as carbon monoxide) through chemical reactions; and a parallel adsorption unit group as a deep purification stage, which removes residual impurities (such as oxygen, water vapor and carbon monoxide) through physical adsorption, thereby achieving fine purification of the circulating working fluid.

[0037] The supercritical carbon dioxide Brayton cycle working fluid purification system provided in this embodiment forms a multi-stage purification process by setting up a first filtration unit 1, a catalytic conversion unit 2, and a parallel adsorption unit. It systematically solves the pollution problems of solid particulate impurities, corrosive gases (such as oxygen and water vapor), and harmful components (such as carbon monoxide) in the circulating working fluid, and achieves multiple goals of equipment protection, safety improvement, and efficiency optimization, thereby ensuring that the supercritical carbon dioxide Brayton cycle system can operate safely and stably.

[0038] The supercritical carbon dioxide Brayton cycle working fluid purification system provided in this embodiment draws the working fluid from the high-temperature side inlet front pipe of the regenerator 13 in the supercritical carbon dioxide Brayton cycle system, so that the working fluid does not need to be reheated before entering the catalytic conversion unit 2. Its own temperature can meet the reaction requirements for catalytic conversion of carbon monoxide into carbon dioxide, thereby reducing energy consumption.

[0039] The inlet of the first filter unit 1 is connected to the front end of the high-temperature side inlet pipe of the regenerator 13 in the supercritical carbon dioxide Brayton cycle system. It can be understood that in the supercritical carbon dioxide Brayton cycle system, the regenerator 13 is used to recover the heat of the turbine exhaust and heat the circulating working fluid entering the combustion chamber. The working fluid in the front end of its high-temperature side inlet pipe is in a high-temperature and high-pressure state.

[0040] Specifically, the first filtration unit 1 can use filter elements (such as metal wire mesh, ceramic filter element, etc.) to trap mechanical impurities such as metal particles, oxide debris, and welding residue in the circulating working fluid, preventing them from entering the subsequent catalytic conversion unit 2 and key circulating equipment (such as turbine, regenerator 13), and avoiding wear or blockage of the flow channel by solid particulate impurities.

[0041] The inlet of the catalytic conversion unit 2 is connected to the outlet of the first filtration unit 1, and the outlet of the catalytic conversion unit 2 is connected to the inlet of the parallel adsorption unit group.

[0042] Specifically, the catalytic conversion unit 2 includes a catalyst bed filled with a catalyst suitable for high-temperature environments (such as noble metal catalysts like platinum and palladium, or metal oxide catalysts like copper oxide / zinc oxide). In this embodiment, the catalytic conversion unit 2 can utilize the high temperature of the circulating working fluid itself (heat from the front-end pipe of the regenerator 13) to convert carbon monoxide in the circulating working fluid into carbon dioxide through a catalytic oxidation reaction. Therefore, no additional heating device is needed; the reaction is directly driven by the heat within the circulating system, reducing energy consumption.

[0043] The inlet end of the parallel adsorption unit group is connected to the outlet end of the catalytic conversion unit 2, and the outlet end of the parallel adsorption unit group is connected to the rear pipeline of the cooler 14 in the circulation system, so that the purified circulating working fluid returns to the low temperature section of the circulation system.

[0044] Specifically, the parallel adsorption unit group includes at least two adsorption units arranged in parallel. Each adsorption unit contains an adsorbent bed filled with a multifunctional adsorbent, which may include molecular sieves, activated alumina, and activated carbon. Molecular sieves are mainly used to remove water vapor; activated alumina is mainly used to remove moisture and oxygen; and activated carbon is mainly used to adsorb organic matter or residual carbon monoxide. This configuration achieves the following: inhibiting oxidative corrosion by removing residual oxygen, reducing oxidative corrosion caused by contact between metal parts and oxygen; avoiding acid corrosion by removing water vapor, preventing it from reacting with carbon dioxide to form carbonic acid, thus reducing the risk of equipment corrosion; and ensuring the purity of the circulating working fluid by secondary removal of carbon monoxide, ensuring that residual carbon monoxide after catalytic conversion is completely removed, so that the purity of the circulating working fluid meets the ppm level standard requirements.

[0045] Furthermore, in this embodiment, the catalytic conversion unit 2 and at least two adsorption units constituting the parallel adsorption unit group are embedded in the purification branch 10 in an equal-diameter side-line structure. Therefore, the flow rate can be adjusted arbitrarily within the range of 0-100%, allowing for switching into or out of the purification system as needed, thereby achieving safe and efficient purification of the circulating working fluid. Here, the purification branch 10 refers to a parallel branch pipe drawn from the main circulation pipeline of the supercritical carbon dioxide Brayton cycle system. Its function is to introduce part or all of the circulating working fluid into the purification system for purification, and then return the purified circulating working fluid to the main circulation pipeline.

[0046] In some possible implementations disclosed in this application, see [link to relevant documentation]. Figure 1 and Figure 2 As shown, a flow regulating valve 11 is installed on the connecting pipeline between the outlet end of the first filter unit 1 and the high-temperature side inlet of the regenerator 13. The flow regulating valve 11 is configured to adjust the flow rate of the purification branch 10 to 5% of the gas filling amount of the main circuit 12. The gas filling amount of the main circuit 12 is the total mass flow rate of the circulating working fluid when the supercritical carbon dioxide Brayton cycle system is running stably.

[0047] In this embodiment, only 125% of the working fluid in the main loop is extracted for purification, which significantly reduces the volume of circulating working fluid to be processed compared to full-flow purification. Since the circulating working fluid in the purification branch 10 needs to pass through the catalytic conversion and adsorption units sequentially (which may involve pressure loss and process delay), the smaller flow rate can reduce the overall energy consumption of the purification system and avoid affecting the efficiency of the Brayton cycle due to excessive energy consumption in the purification process itself.

[0048] Here, main loop 12 refers to the main circulation pipeline of the supercritical carbon dioxide Brayton cycle system.

[0049] In this embodiment, the flow rate of the purification branch 10 is specifically 5% per hour of the total mass flow rate of the circulating working fluid in the main circulation pipeline when the supercritical carbon dioxide Brayton cycle system is running stably.

[0050] In some possible implementations disclosed in this application, see [link to relevant documentation]. Figure 1 As shown, a second filter unit 9 is provided on the connecting pipe between the outlet end of the parallel adsorption unit group and the rear end pipe of the cooler 14. The second filter unit 9 is configured to intercept the adsorbent particles or catalytic reaction byproducts remaining in the circulating working fluid after being treated by the parallel adsorption unit group.

[0051] It is understandable that the adsorbent bed (such as molecular sieve, activated alumina, activated carbon) of the parallel adsorption unit group may experience fine particle shedding due to vibration, airflow erosion, etc. during long-term operation; the catalytic reaction of catalytic conversion unit 2 may also generate a small amount of byproducts (such as metal oxide debris or reaction polymerization products). Here, the second filtration unit 9 uses filtration elements (such as precision metal filter screen, porous ceramic filter element, etc.) to trap these particulate impurities, which can prevent them from returning to the main circulation pipeline with the purified circulating working fluid, further ensuring the purity of the circulating working fluid.

[0052] In some possible implementations disclosed in this application, see [link to relevant documentation]. Figure 1 As shown, the supercritical carbon dioxide Brayton cycle working fluid purification system also includes a heat exchange unit; the heat exchange unit includes a first flow channel and a second flow channel, the inlet end of the first flow channel is connected to the outlet end of the first filter unit 1, and the outlet end of the first flow channel is connected to the inlet end of the catalytic conversion unit 2. The heat exchange unit is configured to allow the circulating working fluid in the first flow channel to exchange heat with the fluid in the second flow channel in order to cool down the circulating working fluid after it has been treated by the first filter unit 1.

[0053] It is understandable that the catalysts in catalytic conversion unit 2 (such as platinum, palladium, or other precious metals or metal oxides) typically have a specific optimal activity temperature range. If the temperature of the circulating working fluid is too high, it may lead to catalyst deactivation or accelerate its aging. In this scenario, the circulating working fluid introduced by the purification branch 10 is taken from the front end of the high-temperature side inlet pipe of the regenerator 13 and is under high temperature and high pressure, which may easily exceed the optimal activity temperature range of the catalyst. By setting up a heat exchange unit to cool the circulating working fluid, its temperature can be adjusted to the appropriate operating range of the catalyst, avoiding catalyst performance degradation or shortened lifespan due to high temperature.

[0054] Here, the heat exchange unit can adopt a counter-current or parallel flow dual-channel structure, including a first channel and a second channel; the first channel serves as the main path, with its inlet connected to the outlet of the first filter unit 1 and its outlet connected to the inlet of the catalytic conversion unit 2, for conveying the high-temperature circulating working fluid to be cooled; the second channel serves as the heat exchange medium channel, with low-temperature fluid (such as cooling water, low-temperature working fluid in the circulating system, etc.) flowing inside, exchanging heat with the working fluid in the first channel through the pipe wall.

[0055] In the above embodiments, see Figure 1 As shown, the outlet end of the catalytic conversion unit 2 is connected to the inlet end of the second flow channel of the heat exchange unit, and the outlet end of the second flow channel is connected to the inlet end of the parallel adsorption unit group. The heat exchange unit is configured to allow the circulating working medium in the second flow channel, which has been treated by the catalytic conversion unit 2, to perform countercurrent heat exchange with the circulating working medium in the first flow channel, so as to reduce the temperature of the circulating working medium in the first flow channel to the threshold temperature of the carbon monoxide conversion reaction in the catalytic conversion unit 2.

[0056] It is understandable that the circulating working fluid, under high temperature and pressure, will experience a temperature drop as it radiates heat to the surrounding environment when flowing through the catalytic conversion unit 2 and its connecting pipes. Therefore, the temperature of the circulating working fluid entering the second flow channel after passing through the catalytic conversion unit 2 is lower than the temperature of the circulating working fluid that does not enter the catalytic conversion unit 2 (i.e., the first flow channel). In this embodiment, the heat exchange unit utilizes the waste heat of the low-temperature circulating working fluid in the second flow channel to cool the high-temperature circulating working fluid in the first flow channel, saving the additional cooling energy consumed in traditional cooling methods. This also avoids the equipment investment required for separately installing a cooler 14 and a preheater, achieving the recycling of heat and improving system energy efficiency.

[0057] Here, the high-temperature circulating working medium in the first flow channel is approximately 500–600°C, while the low-temperature circulating working medium entering the second flow channel after cooling due to heat dissipation at the outlet of catalytic conversion unit 2 is approximately 350–400°C, forming a stable temperature difference. The threshold temperature is the highest effective temperature for the carbon monoxide conversion reaction within catalytic conversion unit 2 (typically 400–500°C, depending on the catalyst type).

[0058] In the above embodiments, see Figure 1 As shown, a cooling unit 4 is provided on the connecting pipe between the outlet end of the second flow channel and the inlet end of the parallel adsorption unit group. The cooling unit 4 is configured to cool the circulating working fluid after heat exchange by the heat exchange unit.

[0059] Understandably, adsorbents in the adsorption unit (such as molecular sieves, activated alumina, activated carbon, etc.) are usually quite sensitive to temperature and have their optimal operating temperature range. The temperature of the circulating working fluid after heat exchange in the heat exchange unit may still be higher than the optimal operating temperature of the adsorbent. By further cooling through the cooling unit 4, the temperature of the circulating working fluid can be adjusted to the suitable operating range of the adsorbent, ensuring that the adsorbent can efficiently remove residual oxygen, water vapor, carbon monoxide, and other impurities from the circulating working fluid, thereby improving the purification effect of the adsorption unit.

[0060] If the temperature of the circulating medium is too high, it may affect the adsorption performance of the adsorbent, or even cause the adsorbent to deactivate or accelerate its aging. Lowering the temperature of the circulating medium to the suitable operating temperature of the adsorbent can reduce the damage to the adsorbent caused by high temperature, extend the service life of the adsorbent, and reduce the frequency and cost of adsorbent replacement.

[0061] In this embodiment, the cooling unit 4 ensures that the circulating working fluid is at a suitable temperature when it enters the adsorption unit, so that the adsorption unit can play its full role and remove impurities from the circulating working fluid more thoroughly. This ensures that the purity of the circulating working fluid meets the ppm level standard requirements, further improves the purification effect of the entire supercritical carbon dioxide Brayton circulating working fluid purification system, and ensures that the supercritical carbon dioxide Brayton circulating system can operate safely and stably.

[0062] In some possible implementations disclosed in this application, see [link to relevant documentation]. Figure 1 As shown, at least two adsorption units arranged in parallel include a first adsorption unit 5 and a second adsorption unit 6. The first adsorption unit 5 is equipped with a first regeneration heating unit, and the second adsorption unit 6 is equipped with a second regeneration heating unit 8. The first regeneration heating unit and the second regeneration heating unit 8 are used to regenerate and heat the first adsorption unit 5 and the second adsorption unit 6, respectively.

[0063] In this embodiment, each adsorption unit can be regenerated and heated independently without needing to synchronize with other units. For example, when the first adsorption unit 5 becomes saturated and needs regeneration, the second adsorption unit 6 can continue to run the adsorption process, avoiding a complete shutdown of the purification system and improving the continuous operation capability of the purification system.

[0064] In this purification system, when the system includes a cooling unit 4, the inlet ends of both the first adsorption unit 5 and the second adsorption unit 6 are connected to the outlet pipe of the cooling unit 4, and their outlet ends are connected to the main circulation pipe of the circulating working medium returning to the circulation system, thus forming two parallel processing channels. The circulating working medium can flow into these two adsorption units for purification, and the two units work together to perform the purification task of the circulating working medium.

[0065] The purification system also includes a regenerated gas inlet pipe, to which the inlets of the first regeneration heating unit and the second regeneration heating unit 8 are connected. The outlet of the first regeneration heating unit is connected to the pipe containing the first adsorption unit 5 and is in communication with the first adsorption unit 5 during operation; the outlet of the second regeneration heating unit 8 is connected to the pipe containing the second adsorption unit 6 and is in communication with the second adsorption unit 6 during operation.

[0066] The purification system also includes a regenerated gas outlet pipeline. The regenerated gas generated by the first adsorption unit 5 and the second adsorption unit 6 during the regeneration process is collected in the regenerated gas outlet pipeline through their respective pipelines and discharged from the purification system through this pipeline for subsequent treatment or discharge.

[0067] It is understood that valves are installed on the following pipelines to control the flow path and flow rate of the circulating working fluid and regenerated gas: the corresponding pipelines connecting the first adsorption unit 5 and the second adsorption unit 6 to the outlet pipeline of the cooling unit 4; the corresponding pipelines connecting the first adsorption unit 5 and the second adsorption unit 6 to the main circulation pipeline of the circulating working fluid returning to the circulation system; the corresponding pipelines connecting the first adsorption unit 5 and the second adsorption unit 6 to the regenerated gas outlet pipeline; and the corresponding pipelines connecting the regenerated gas inlet pipeline to the first regeneration heating unit and the second regeneration heating unit 8.

[0068] Specifically, taking the first adsorption unit 5 in adsorption state and the second adsorption unit 6 in regeneration state as an example, the valve states and the directions of the circulating working medium and regeneration gas flow are explained as follows: The valve from the outlet of the cooling unit 4 to the first adsorption unit 5 is open, allowing the circulating working medium to flow from the cooling unit 4 into the first adsorption unit 5; the valve from the first adsorption unit 5 to the return pipeline of the circulation system is open, allowing the purified circulating working medium to return to the main circulation pipeline of the circulation system; the valve from the regeneration gas inlet pipeline to the first regeneration heating unit is closed to prevent the regeneration gas from mixing into the purified circulating working medium; the valve from the first adsorption unit 5 to the regeneration gas outlet pipeline is closed to prevent the circulating working medium from being accidentally discharged through the regeneration gas outlet pipeline. The valve from the outlet of cooling unit 4 to the second adsorption unit 6 is closed, suspending the adsorption process of the second adsorption unit 6 to prevent unregenerated adsorbent from contacting the circulating working fluid; the valve from the second adsorption unit 6 to the return pipeline of the circulation system is closed to prevent regeneration gas and impurities in the regeneration process from entering the main circulation pipeline of the circulation system; the valve from the regeneration gas inlet pipeline to the second regeneration heating unit 8 is opened, and the regeneration gas flows into the second regeneration heating unit 8 through the regeneration gas inlet pipeline, is heated to the temperature required for regeneration, and then enters the second adsorption unit 6 for regeneration treatment; the valve from the second adsorption unit 6 to the regeneration gas outlet pipeline is opened to discharge the impurities and regeneration gas desorbed during the regeneration process of the second adsorption unit 6.

[0069] Furthermore, to achieve automated control of the purification system, all of the above valves are solenoid valves.

[0070] In the above embodiments, the supercritical carbon dioxide Brayton cycle working fluid purification system further includes a control system; the control system is configured to execute adsorption-regeneration switching logic, including: when the first adsorption unit 5 is in the adsorption state, the second adsorption unit 6 simultaneously enters the regeneration state, the second regeneration heating unit 8 is started and delivers regeneration gas to the second adsorption unit 6; when the second adsorption unit 6 reaches a preset regeneration degree, the control system switches the first adsorption unit 5 to enter the regeneration state, and at the same time switches the second adsorption unit 6 to the adsorption state, so as to achieve continuous purification of the circulating working fluid through alternating cycles.

[0071] In this embodiment, when one adsorption unit becomes saturated and requires regeneration, the other adsorption unit can still maintain the adsorption process, ensuring that the purification process of the circulating working fluid is uninterrupted and guaranteeing the continuous and stable operation of the supercritical carbon dioxide Brayton cycle system. This avoids a decrease in the efficiency or failure of the main system due to the shutdown of the purification system. Simultaneously, the two adsorption units achieve continuous purification of the circulating working fluid through an alternating "adsorption-regeneration" mode. Compared to the design where a single adsorption unit needs to be shut down for regeneration, this significantly improves the purification capacity per unit time, ensuring that the purity of the working fluid always meets the ppm level standard requirements. Furthermore, the regeneration heating unit only starts when the corresponding adsorption unit needs regeneration, avoiding the energy waste caused by frequent start-stop operations or long-term heating during the regeneration process in traditional single adsorption unit systems, thus reducing the overall energy consumption of the system.

[0072] Here, the control system, based on a preset adsorption-regeneration switching logic, precisely controls the opening and closing states of the solenoid valves and the regeneration heating unit to achieve the switching of the flow direction and flow distribution of the circulating working fluid and regeneration gas, thereby ensuring the automated and coordinated operation of the two adsorption units. Specifically, when the first adsorption unit 5 is in the adsorption state, the control system opens the solenoid valves of its inlet and outlet pipelines, allowing the circulating working fluid to flow in and complete the purification; simultaneously, it controls the corresponding solenoid valve of the second adsorption unit 6 to close the adsorption passage and open the regeneration heating and regeneration gas passages, initiating the regeneration process. Once the second adsorption unit 6 reaches the preset regeneration conditions, the control system immediately executes the valve state switching, causing the two adsorption units to interchange their working states, forming an alternating cycle. The specific logic and parameter settings for valve state control have been explained in detail above in conjunction with different adsorption and regeneration conditions and switching processes, and will not be repeated here.

[0073] In the above embodiments, see Figure 1 As shown, the adsorption-regeneration switching logic also includes: sampling and analyzing the circulating working fluid after it has been processed by the parallel adsorption unit group, and determining whether the corresponding adsorption unit has reached the preset regeneration degree based on the sampling and analysis results, so as to trigger the switching of the adsorption-regeneration state.

[0074] In this embodiment, through the feedback mechanism of sampling analysis, the purification system can adapt to circulating working fluids from different sources and with different levels of pollution, achieving effective control over the purification level. Simultaneously, the sampling analysis results can serve as monitoring parameters for the purification system's operating status, enabling early detection of potential problems such as performance degradation of the adsorption unit and malfunctions of the regeneration heating unit, providing data support for preventative maintenance.

[0075] Here, if the concentration of impurities in the circulating working fluid after adsorption is detected to be lower than the first preset concentration threshold, it indicates that the adsorbent in the corresponding adsorption unit still has adsorption capacity, and the current state is maintained. If the concentration reaches or exceeds the first preset concentration threshold, the following logic is triggered: the corresponding adsorption unit stops working and enters the regeneration state, while another adsorption unit connected in parallel switches to the adsorption state. For example, if the moisture content is >50ppm, the adsorbent is determined to be ineffective.

[0076] Furthermore, the exhaust gas discharged during the regeneration process can be sampled and analyzed. By detecting the concentration of desorbed impurities and the regeneration efficiency, the adsorption-regeneration switching logic can be further optimized. Specifically: if the impurity concentration in the regenerated exhaust gas is higher than the second preset concentration threshold, it indicates that the adsorption unit is not regenerated sufficiently. At this time, the system automatically extends the regeneration time or increases the regeneration heating power to ensure that the adsorbent fully recovers its activity. If the impurity concentration is lower than the second concentration threshold, the regeneration is determined to be complete, triggering the switching logic. The adsorption unit switches to the adsorption state and takes over from another adsorption unit that has reached adsorption saturation, thus forming a dynamically balanced purification cycle. This mechanism achieves precise control of the working state of the adsorption unit by monitoring the regeneration effect in real time, ensuring the continuity and efficiency of the circulating working fluid purification process.

[0077] It should be noted that the adsorption-regeneration switching logic can also be combined with the two sampling and analysis mechanisms mentioned above to achieve precise control of the entire process of the adsorption unit's operating status. In this control logic, the sampling and analysis of the recirculated working fluid after adsorption has a higher priority than the sampling and analysis of the regenerated waste gas.

[0078] In some possible embodiments disclosed in this application, the control system is further configured to execute a pre-adjustment program for the purification strategy. The pre-adjustment program includes: based on the sampling and analysis data of the circulating working fluid at the inlet of the purification branch 10 (such as impurity type, concentration, and parameters such as working fluid temperature and pressure), combined with historical operating data and preset models, dynamically adjusting the operating parameters of each purification unit (such as the first filtration unit 1, catalytic conversion unit 2, and adsorption unit group) in advance to adapt to changes in the pollution status of the circulating working fluid in the circulation system; and based on the sampling and analysis data of the circulating working fluid after treatment by the catalytic conversion unit 2 (such as carbon monoxide conversion rate, catalyst activity decay trend, and circulating working fluid temperature fluctuation), evaluating the catalytic reaction efficiency in real time and fine-tuning the reaction conditions of the catalytic conversion unit 2 (such as increasing the catalyst bed residence time and optimizing the airflow distribution).

[0079] Here, to monitor the initial contamination status of the circulating working fluid in the circulation system in real time and dynamically optimize the purification strategy, the purification device also includes sampling and analyzing the circulating working fluid at the inlet of purification branch 10. Specifically, it detects the types and concentrations of impurities (such as solid particle content, carbon monoxide, oxygen, water vapor, etc.) in the circulating working fluid at the inlet of purification branch 10 to determine whether the contamination level of the circulation system exceeds design expectations. Based on the contamination concentration of the inlet circulating working fluid, it automatically adjusts the flow rate of purification branch 10 (e.g., increasing it from 5% to 10% of the flow rate of main loop 12), or switches the number of parallel adsorption units in operation (e.g., increasing it from 2 units to 3 units) to ensure that the purification capacity matches the contamination load.

[0080] Here, to monitor the reaction efficiency of catalytic conversion unit 2 in real time and ensure the treatment effect of subsequent adsorption units, the purification device also includes sampling and analyzing the circulating working fluid after treatment by catalytic conversion unit 2. Specifically, the concentration of carbon monoxide in the circulating working fluid after catalytic conversion is detected to confirm whether it has been fully converted into carbon dioxide through catalytic oxidation, thus preventing unreacted carbon monoxide from entering the adsorption unit and increasing its treatment load. In this case, the trend of carbon monoxide concentration change after catalysis is continuously monitored. If a decrease in carbon monoxide conversion rate is found under the same operating conditions (e.g., from 90% to 70%), early warning of problems such as catalyst aging, poisoning, or bed blockage can be provided, facilitating timely replacement or regeneration of the catalyst and preventing a sudden drop in system purification efficiency.

[0081] In some possible implementations disclosed in this application, see [link to relevant documentation]. Figure 1 As shown, the catalytic conversion unit 2 and at least two adsorption units constituting the parallel adsorption unit group are all pressure vessels, and each is equipped with a safety valve.

[0082] In this embodiment, the pressure vessel structure of the catalytic conversion unit 2 and the adsorption unit can withstand the high temperature and high pressure environment of the supercritical carbon dioxide working fluid, and is fully compatible with the operating pressure of the circulation system. Therefore, the circulating working fluid does not need to be depressurized when flowing in the purification branch 10, and always maintains a supercritical state, avoiding energy loss and working fluid performance fluctuations caused by phase change. At the same time, since the purification unit maintains the same pressure as the main circulation system, the purified working fluid can be directly returned to the rear pipeline of the cooler 14 through the pipeline, without the need for additional pressurization equipment (such as a compressor). This design simplifies the system process, reduces energy consumption, and avoids the risk of secondary pollution that may be introduced by pressurization.

[0083] Here, the safety valves configured in each unit can automatically release pressure when the internal pressure exceeds the design threshold (such as 1.1 times the working pressure), preventing overpressure risks caused by valve malfunction, pipeline blockage, or uncontrolled exothermic reaction, and providing safety redundancy for long-term stable operation under high temperature and high pressure environments.

[0084] It will be readily understood by those skilled in the art that the aforementioned advantageous methods can be freely combined and superimposed without conflict.

[0085] The above are merely preferred embodiments of this application and are not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the protection scope of this application. The above are merely preferred embodiments of this application. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of this application, and these improvements and modifications should also be considered within the protection scope of this application.

Claims

1. A supercritical carbon dioxide Brayton cycle working fluid purification system, characterized in that, include: The first filtration unit is connected to the high-temperature side inlet front pipeline of the regenerator in the supercritical carbon dioxide Brayton cycle system, and is configured to intercept solid particulate impurities in the circulating working fluid. A catalytic conversion unit, wherein the inlet end of the catalytic conversion unit is connected to the outlet end of the first filtration unit, and the catalytic conversion unit is provided with a catalyst bed, configured to catalytically convert carbon monoxide contained in the circulating working fluid after being treated by the first filtration unit into carbon dioxide; The parallel adsorption unit group includes at least two adsorption units arranged in parallel. The inlet end of each adsorption unit is connected to the outlet end of the catalytic conversion unit, and the outlet end of each adsorption unit is connected to the rear end pipeline of the cooler in the supercritical carbon dioxide Brayton cycle system. The adsorption unit is provided with an adsorbent bed, configured to remove residual oxygen, water vapor and carbon monoxide in the circulating working fluid after being treated by the catalytic conversion unit.

2. The supercritical carbon dioxide Brayton cycle working fluid purification system according to claim 1, characterized in that, A flow regulating valve is provided on the connecting pipeline between the outlet end of the first filter unit and the high-temperature side inlet of the regenerator. The flow regulating valve is configured to adjust the flow rate of the purification branch to 5% of the gas filling amount of the main circuit. The main loop gas loading amount is the total mass flow rate of the circulating working fluid when the supercritical carbon dioxide Brayton cycle system is running stably.

3. The supercritical carbon dioxide Brayton cycle working fluid purification system according to claim 1, characterized in that, A second filter unit is provided on the connecting pipe between the outlet end of the parallel adsorption unit group and the rear end pipe of the cooler. The second filter unit is configured to intercept the adsorbent particles or catalytic reaction byproducts remaining in the circulating working fluid after being treated by the parallel adsorption unit group.

4. The supercritical carbon dioxide Brayton cycle working fluid purification system according to claim 1, characterized in that, Also includes: The heat exchange unit includes a first flow channel and a second flow channel. The inlet end of the first flow channel is connected to the outlet end of the first filter unit, and the outlet end of the first flow channel is connected to the inlet end of the catalytic conversion unit. The heat exchange unit is configured to allow the circulating working fluid in the first flow channel to exchange heat with the fluid in the second flow channel in order to cool the circulating working fluid after it has been treated by the first filter unit.

5. The supercritical carbon dioxide Brayton cycle working fluid purification system according to claim 4, characterized in that, The outlet end of the catalytic conversion unit is connected to the inlet end of the second flow channel of the heat exchange unit, and the outlet end of the second flow channel is connected to the inlet end of the parallel adsorption unit group. The heat exchange unit is configured to allow the circulating working fluid in the second flow channel, which has been treated by the catalytic conversion unit, to perform countercurrent heat exchange with the circulating working fluid in the first flow channel, so as to reduce the temperature of the circulating working fluid in the first flow channel to the threshold temperature of the carbon monoxide conversion reaction in the catalytic conversion unit.

6. The supercritical carbon dioxide Brayton cycle working fluid purification system according to claim 5, characterized in that, A cooling unit is provided on the connecting pipe between the outlet end of the second flow channel and the inlet end of the parallel adsorption unit group. The cooling unit is configured to cool the circulating working fluid after heat exchange by the heat exchange unit.

7. The supercritical carbon dioxide Brayton cycle working fluid purification system according to claim 1, characterized in that, The adsorption unit, which is arranged in at least two parallel configurations, includes a first adsorption unit and a second adsorption unit. The first adsorption unit is equipped with a first regeneration heating unit, and the second adsorption unit is equipped with a second regeneration heating unit. The first regeneration heating unit and the second regeneration heating unit are used to regenerate and heat the first adsorption unit and the second adsorption unit, respectively.

8. The supercritical carbon dioxide Brayton cycle working fluid purification system according to claim 7, characterized in that, Also includes: The control system, configured to execute adsorption-regeneration switching logic, includes: When the first adsorption unit is in the adsorption state, the second adsorption unit simultaneously enters the regeneration state, the second regeneration heating unit starts and supplies regeneration gas to the second adsorption unit; When the second adsorption unit reaches the preset regeneration level, the control system switches the first adsorption unit into the regeneration state and simultaneously switches the second adsorption unit into the adsorption state, thereby achieving continuous purification of the circulating working fluid through alternating cycles.

9. The supercritical carbon dioxide Brayton cycle working fluid purification system according to claim 8, characterized in that, The adsorption-regeneration switching logic also includes: The circulating working fluid after being processed by the parallel adsorption unit group is sampled and analyzed, and the corresponding adsorption unit is determined to have reached the preset regeneration degree based on the sampling and analysis results, so as to trigger the switching of adsorption-regeneration state.

10. The supercritical carbon dioxide Brayton cycle working fluid purification system according to claim 1, characterized in that, The catalytic conversion unit and at least two adsorption units constituting the parallel adsorption unit group are all pressure vessels and are equipped with safety valves.

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