Shaft end seal structure and supercritical carbon dioxide power generation system

Abstract

This application discloses a shaft end sealing structure and a supercritical carbon dioxide power generation system, belonging to the technical field of supercritical carbon dioxide power generation systems. Its main purpose is to create effective isolation between the system's interior and the atmosphere, preventing external environmental pollution of the system's interior. The main technical solution of this application is as follows: The shaft end sealing structure includes a dry gas sealing chamber, a leakage recovery chamber, and an isolation gas chamber, sequentially arranged at both ends of the main shaft extension along the direction from the medium side to the atmosphere side. The dry gas sealing chamber is used to install a dry gas seal to prevent medium leakage; the leakage recovery chamber is used to collect and recover leaked medium; and the isolation gas chamber is used to introduce isolation gas to prevent external gases from entering.

Description

Technical Field

[0001] This application belongs to the technical field of supercritical carbon dioxide power generation systems, specifically relating to a shaft end sealing structure and a supercritical carbon dioxide power generation system. Background Technology

[0002] Supercritical carbon dioxide power generation systems employ closed-loop Brayton cycles, requiring extremely high cleanliness of the internal working fluid during operation. Air, moisture, dust, and other impurities from the external environment are strictly prohibited from entering the working fluid circuit. However, in the main shaft extension sections of core rotating machinery such as turbines and compressors, traditional shaft end sealing structures only include a main seal and a simple gas seal. External gas can easily enter the sealing cavity and the system interior in reverse along the shaft end gap. Summary of the Invention

[0003] In view of this, this application provides a shaft end sealing structure and a supercritical carbon dioxide power generation system, which aims to form an effective isolation between the system interior and the atmosphere, and avoid external environmental pollution to the system interior.

[0004] To achieve the above objectives, this application mainly provides the following technical solutions: One aspect of this application provides a shaft end sealing structure, characterized in that it includes a dry gas sealing cavity, a leakage recovery cavity, and an isolation gas cavity sequentially arranged at both ends of the shaft extension along the direction from the medium side to the atmosphere side; The dry gas sealing cavity is used to install a dry gas seal to prevent media leakage; The leakage recovery chamber is used to collect and recover leaked media; The isolation chamber is used to introduce isolation gas to prevent external gas from entering.

[0005] Optionally, the shaft end sealing structure further includes: Internal compensation system; The internal replenishment system is connected to the dry gas sealing cavity, and the internal replenishment system includes a first replenishment branch and a second replenishment branch. The first gas replenishment branch is connected to the gas injection system and is used to draw gas from the gas injection system and supply gas to the dry gas sealing cavity in order to establish and maintain the internal pressure of the dry gas sealing cavity higher than the pressure on the medium side, so as to prevent the medium on the medium side from entering the dry gas sealing cavity. The second gas supply branch is connected to the inside of the system and is used to draw gas from the inside of the system and supply gas to the dry gas sealing cavity, so as to establish and maintain the pressure inside the dry gas sealing cavity higher than the pressure on the medium side, and prevent the medium on the medium side from entering the dry gas sealing cavity.

[0006] Optionally, the shaft end sealing structure further includes: Pressurization system; The pressurization system is connected to the internal compensation system and the dry gas sealing cavity respectively. The pressurization system is used to increase the gas pressure when the output gas pressure of the internal compensation system is insufficient, and to establish a positive pressure difference between the internal pressure of the dry gas sealing cavity and the medium side pressure, so as to prevent the medium on the medium side from entering the dry gas sealing cavity.

[0007] Optionally, the first gas supply branch and the second gas supply branch are independent of each other. The first gas supply branch and the second gas supply branch can be selected to directly supply gas to the dry gas sealing cavity, or to supply gas to the dry gas sealing cavity after being pressurized by the pressurization system.

[0008] Optionally, the pressurization system includes a pressurizing component, a pressure regulating device, and a gas supply pipeline; the gas supply pipeline is used to connect the pressurization system with the internal compensation system and the dry gas sealing cavity; the pressurizing component is disposed on the gas supply pipeline to increase the gas pressure entering the dry gas sealing cavity; the pressure regulating device is disposed on the gas supply pipeline to regulate and stabilize the gas pressure input to the dry gas sealing cavity after being boosted by the pressurizing component, ensuring that the internal pressure of the dry gas sealing cavity is higher than the medium side pressure.

[0009] Optionally, the shaft end sealing structure further includes: Leakage recovery system; The leakage recovery system is connected to the leakage recovery chamber, and the leakage recovery system includes a recovery pipeline and a filtration device; The filtration device is installed on the recovery pipeline to filter out isolation gas and impurities, and the leakage recovery system is used to recover the filtered leakage medium to the working fluid system.

[0010] Optionally, the shaft end sealing structure further includes: Isolation gas system; The isolation gas system is connected to the isolation gas cavity. The isolation gas system includes a first isolation gas branch and a second isolation gas branch, with the first isolation gas branch and the second isolation gas branch being used and the other being a backup. The isolation gas system is used to introduce isolation gas into the isolation gas chamber, so that the pressure inside the isolation gas chamber is higher than the atmospheric pressure and higher than the pressure inside the leakage recovery chamber.

[0011] Optionally, the first isolation gas branch is used to introduce nitrogen, and the second isolation gas branch is used to introduce compressed air.

[0012] Optionally, the isolation gas system further includes an isolation gas recovery hood; The isolation gas recovery hood is located at one end of the isolation gas cavity near the atmosphere and is used to recover the isolation gas that leaks from the isolation gas cavity to the atmosphere.

[0013] Another aspect of this application provides a supercritical carbon dioxide power generation system, including the shaft end sealing structure described in any one of the above claims.

[0014] By employing the above technical solution, this application has at least the following beneficial effects: The shaft end sealing structure and supercritical carbon dioxide power generation system provided in this application, by sequentially setting a dry gas sealing chamber, a leakage recovery chamber, and an isolation gas chamber at both ends of the main shaft extension from the medium side to the atmosphere side, can effectively prevent the medium from leaking outward by using the dry gas seal installed in the dry gas sealing chamber, collect and recover the leaked medium through the leakage recovery chamber, and prevent external gas from entering by the isolation gas introduced into the isolation gas chamber, thereby forming a multi-stage sealing protection at the main shaft extension, realizing reliable sealing and leakage recovery of the medium, effectively isolating external gas intrusion, and improving the overall reliability and safety of the shaft end seal. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the shaft end sealing structure of an optional embodiment of this application; Figure 2 This is a gas flow diagram of an optional embodiment of the shaft end sealing structure of this application.

[0016] The reference numerals in the attached figures are as follows: 1. Dry gas sealing chamber; 2. Leakage recovery chamber; 3. Isolation gas chamber; 100. Internal replenishment system; 200. Pressurization system; 300. Leakage recovery system; 400. Isolation gas system; 401. Isolation gas recovery hood. Detailed Implementation

[0017] 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.

[0018] 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.

[0019] 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.

[0020] 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.

[0021] See Figure 1 and Figure 2 As shown, an embodiment of the first aspect of this application provides a shaft end sealing structure, and an embodiment of the second aspect of this application provides a supercritical carbon dioxide power generation system.

[0022] Among them, the shaft end sealing structure is used in supercritical carbon dioxide power generation systems.

[0023] Specifically, supercritical carbon dioxide power generation systems include, but are not limited to, rotating machinery such as turbines and compressors, and shaft end sealing structures are used in the main shaft extension parts of rotating machinery such as turbines and compressors.

[0024] Furthermore, the shaft end sealing structure provided in the embodiment of the first aspect of this application includes a dry gas sealing chamber 1, a leakage recovery chamber 2, and an isolation gas chamber 3 arranged sequentially at the shaft extensions at both ends of the main shaft along the direction from the medium side to the atmosphere side; the dry gas sealing chamber 1 is used to install a dry gas seal to prevent medium leakage; the leakage recovery chamber 2 is used to collect and recover the leaked medium; and the isolation gas chamber 3 is used to introduce isolation gas to prevent external gas from entering.

[0025] The shaft end sealing structure provided in this embodiment of the application, by sequentially arranging a dry gas sealing chamber 1, a leakage recovery chamber 2, and an isolation gas chamber 3 from the medium side to the atmosphere side at both ends of the main shaft extension, can effectively prevent the medium from leaking outward by using the dry gas seal installed in the dry gas sealing chamber 1, collect and recover the leaked medium through the leakage recovery chamber 2, and prevent external gas from entering by using the isolation gas introduced into the isolation gas chamber 3, thereby forming a multi-level sealing protection at the main shaft extension, realizing reliable sealing and leakage recovery of the medium, effectively isolating external gas intrusion, and improving the overall reliability and safety of the shaft end seal.

[0026] It is understood that the dry gas sealing chamber 1, the leakage recovery chamber 2, and the isolation chamber 3 are sequentially separated at the shaft extensions at both ends of the main shaft along the direction from the medium side to the atmosphere side, forming a continuous and independent cavity structure. Adjacent cavities are connected by a radial gap between the main shaft and the sealing seat, thus sequentially constituting the dry gas sealing chamber 1 near the medium side, the leakage recovery chamber 2 in the middle region, and the isolation chamber 3 near the atmosphere side. Here, the sealing seat refers to the stationary shell that surrounds the main shaft and forms the dry gas sealing chamber 1, the leakage recovery chamber 2, and the isolation chamber 3.

[0027] It is understandable that the dry gas seal installed in the dry gas sealing chamber 1 can be a multi-stage dry gas seal. The multi-stage dry gas seal uses a gas with the same composition as the working gas on the medium side as the sealing gas source, so that the sealing gas leaking into the leakage recovery chamber 2 can be recovered and reused as the system medium. Similarly, the sealing gas source can directly use the internal medium of the system or the medium gas source that supplies gas to the system, without the need to set up an additional independent sealing gas supply system.

[0028] It is understood that a sealing gas with a preset pressure is introduced into the dry gas sealing cavity 1, so that the internal pressure of the dry gas sealing cavity 1 is higher than the pressure on the medium side. Here, the preset pressure refers to a stable pressure value that is set and maintained in advance. This pressure value is higher than the pressure on the medium side, which can ensure that the internal pressure of the dry gas sealing cavity 1 is always greater than the pressure on the medium side, and ensure that the dry gas seal can work stably and reliably. This application does not limit its specific value.

[0029] It can be understood that the leakage recovery chamber 2 is located between the dry gas sealing chamber 1 and the isolation gas chamber 3, which can centrally collect the small amount of leaked medium, i.e., the aforementioned sealing gas, after the dry gas seal, to prevent the leaked medium from directly entering the atmosphere or polluting the internal environment of the isolation gas chamber 3. At the same time, it facilitates the unified recycling and treatment of the collected leaked medium, thereby improving the medium utilization rate, reducing the medium loss, and ensuring the economy and cleanliness of the supercritical carbon dioxide power generation system.

[0030] Understandably, the isolation chamber 3 is located closest to the atmosphere. Isolation gas, such as nitrogen or compressed air, is introduced into the isolation chamber 3 to make the internal pressure of the isolation chamber 3 higher than the atmospheric pressure. By continuously introducing isolation gas, a positive pressure barrier is formed inside the isolation chamber 3, which can effectively prevent impurities such as air, moisture and dust from the external environment from entering the sealed structure, avoid contaminating the working fluid inside the system, and ensure the cleanliness and safety of the supercritical carbon dioxide power generation system.

[0031] In some possible implementations disclosed in this application, see [link to relevant documentation]. Figure 2As shown, the shaft end sealing structure also includes an internal replenishment system 100; the internal replenishment system 100 is connected to the dry gas sealing cavity 1, and the internal replenishment system 100 includes a first replenishment branch and a second replenishment branch; the first replenishment branch is connected to the injection replenishment system and is used to draw gas from the injection replenishment system and supply gas to the dry gas sealing cavity 1 to establish and maintain the internal pressure of the dry gas sealing cavity 1 higher than the pressure on the medium side, so as to prevent the medium on the medium side from entering the dry gas sealing cavity 1; the second replenishment branch is connected to the system interior and is used to draw gas from the system interior and supply gas to the dry gas sealing cavity 1 to establish and maintain the internal pressure of the dry gas sealing cavity 1 higher than the pressure on the medium side, so as to prevent the medium on the medium side from entering the dry gas sealing cavity 1.

[0032] In this embodiment, by coordinating the two air supply branches, the internal pressure of the dry gas sealing cavity 1 can be flexibly and stably established and maintained to be higher than the pressure on the medium side, effectively preventing the medium on the medium side from entering the dry gas sealing cavity 1, ensuring the continuous and reliable operation of the dry gas seal, and improving the working stability and applicability of the shaft end sealing structure.

[0033] It is understood that two gas supply channels are respectively opened on the aforementioned sealing seat at the position relative to the dry gas sealing cavity 1, to connect the first gas supply branch and the second gas supply branch respectively. During the initial start-up and normal operation of the shaft end sealing structure, the internal replenishment system 100, through its included first and second gas supply branches, works together to continuously provide a stable gas supply to the dry gas sealing cavity 1, so as to establish a positive pressure difference between the dry gas sealing cavity 1 and the medium side. During the actual operation of the system, when the pressure difference between the dry gas sealing cavity 1 and the medium side fluctuates or is insufficient, either the first or second gas supply branch can be flexibly selected to be activated, or both gas supply branches can be activated simultaneously for gas supply and pressure replenishment, depending on the actual operating conditions of the system. The first gas supply branch draws gas from the gas injection system, while the second gas supply branch draws gas from the supercritical carbon dioxide power generation system. The gas from both branches is continuously supplied to the dry gas sealing chamber 1 through corresponding gas supply channels. Through the synergistic pressure replenishment effect of the two gas supply lines, a positive pressure differential is stably maintained, ensuring that the internal pressure of the dry gas sealing chamber 1 is higher than the pressure on the medium side. This dual-branch pressure replenishment effectively establishes and maintains a pressure barrier that prevents the medium from intruding into the dry gas sealing chamber 1, avoiding failure of the dry gas seal due to medium intrusion. Simultaneously, it ensures the stability of the internal pressure of the dry gas sealing chamber 1, thereby further improving the overall sealing reliability and operational stability of the shaft end sealing structure. Here, the gas injection system refers to the medium gas source system that supplies gas to the system, i.e., the working fluid system.

[0034] In some possible implementations disclosed in this application, see [link to relevant documentation]. Figure 2As shown, the shaft end sealing structure also includes a pressurizing system 200; the pressurizing system 200 is connected to the internal compensation system 100 and the dry gas sealing cavity 1 respectively. The pressurizing system 200 is used to increase the gas pressure when the output gas pressure of the internal compensation system 100 is insufficient, and to establish a positive pressure difference between the internal pressure of the dry gas sealing cavity 1 and the medium side pressure, so as to prevent the medium on the medium side from entering the dry gas sealing cavity 1.

[0035] In this embodiment, the pressurization system 200 can effectively compensate for the insufficient gas supply pressure of the internal compensation system 100. When the output gas pressure of the internal compensation system 100 is insufficient and cannot stably establish and maintain the internal pressure of the dry gas sealing cavity 1 higher than the medium side pressure, the pressurization system 200 can intervene in time and increase the gas pressure to ensure that a positive pressure difference can be stably established between the internal pressure of the dry gas sealing cavity 1 and the medium side pressure. This effectively prevents the medium from entering the dry gas sealing cavity 1, ensuring that the dry gas seal is always in a stable and reliable working state. It further enhances the gas supply effect of the internal compensation system 100, avoids the failure of the shaft end sealing structure due to insufficient gas supply pressure of the internal compensation system 100, improves the overall working stability, reliability and anti-interference ability of the shaft end sealing structure, and ensures that the main shaft extension of the rotating machinery in the supercritical carbon dioxide power generation system can achieve continuous and effective sealing protection.

[0036] In the above embodiments, see Figure 2 As shown, the first air supply branch and the second air supply branch are independent of each other. The first air supply branch and the second air supply branch can be selected to supply air directly to the dry gas sealing chamber 1, or to supply air to the dry gas sealing chamber 1 after being pressurized by the pressurization system 200.

[0037] It is understandable that the first and second air supply branches are set up independently. Both air supply branches have two air supply modes: one is to supply air directly to the dry gas sealing chamber 1, and the other is to supply air to the dry gas sealing chamber 1 after being pressurized by the pressurization system 200. The two air supply modes form a bypass pipeline cooperation relationship.

[0038] Understandably, when the gas pressure output by the internal replenishment system 100 meets the usage requirements, the first and second replenishment gas branches can directly supply gas to the dry gas sealing chamber 1. When the gas pressure output by the internal replenishment system 100 is insufficient, the two replenishment gas branches can be switched to supply gas to the dry gas sealing chamber 1 after being pressurized by the pressurization system 200. This effectively compensates for the insufficient gas supply pressure of the internal replenishment system 100, ensures the stable establishment and maintenance of a positive pressure difference between the internal pressure of the dry gas sealing chamber 1 and the medium side pressure, prevents the medium from entering the dry gas sealing chamber 1, ensures that the dry gas seal is always in a stable and reliable working state, further enhances the replenishment effect of the internal replenishment system 100, avoids the failure of the shaft end sealing structure due to insufficient gas supply pressure of the internal replenishment system 100, improves the overall working stability, reliability and anti-interference ability of the shaft end sealing structure, and ensures that the main shaft extension of the rotating machinery in the supercritical carbon dioxide power generation system can achieve continuous and effective sealing protection.

[0039] In the above embodiments, the pressurization system 200 includes a pressurization component, a pressure regulating device, and a gas supply pipeline; the gas supply pipeline is used to connect the pressurization system 200 with the internal compensation system 100 and the dry gas sealing chamber 1; the pressurization component is installed on the gas supply pipeline to increase the gas pressure entering the dry gas sealing chamber 1; the pressure regulating device is installed on the gas supply pipeline to regulate and stabilize the gas pressure input to the dry gas sealing chamber 1 after being boosted by the pressurization component, ensuring that the internal pressure of the dry gas sealing chamber 1 is higher than the medium side pressure.

[0040] Understandably, the gas supply pipeline is used to connect the pressurization system 200 with the internal compensation system 100 and the dry gas sealing chamber 1, providing a channel for gas flow; the pressurization component is installed on the gas supply pipeline to increase the gas pressure entering the dry gas sealing chamber 1, and it is preferably selected as a diaphragm-type micro booster pump or a piston-type micro booster pump; the pressure regulating device is also installed on the gas supply pipeline to regulate and stabilize the gas pressure input to the dry gas sealing chamber 1 after being boosted by the pressurization component, ensuring that the internal pressure of the dry gas sealing chamber 1 is always higher than the medium side pressure, and it is selected as a self-operated pressure regulating valve or an electrically controlled pressure regulating device. The electrically controlled pressure regulating device consists of a pressure sensor, an electric regulating valve, and a controller.

[0041] Understandably, the pressurization system 200 operates as follows: the gas supply pipeline first connects the pressurization system 200 with the internal compensation system 100 and the dry gas sealing chamber 1, ensuring that the gas output from the internal compensation system 100 can smoothly enter the pressurization system 200 and ultimately be delivered to the dry gas sealing chamber 1. When the gas pressure output by the internal compensation system 100 is insufficient and cannot stably establish and maintain the internal pressure of the dry gas sealing chamber 1 above the medium side pressure, the pressurization system 200 intervenes in time. The pressurization component installed on the gas supply pipeline is activated to pressurize the gas from the internal compensation system 100, raising the gas pressure to the preset requirement. Subsequently, the pressure regulating device installed on the gas supply pipeline starts working to regulate and stabilize the gas pressure after it has been boosted by the pressurizing component, avoiding pressure fluctuations and ensuring that the gas pressure input to the dry gas sealing chamber 1 is stable and higher than the medium side pressure. This effectively compensates for the gas supply pressure deficiency of the internal compensation system 100, prevents the medium side from entering the dry gas sealing chamber 1, ensures that the dry gas seal is always in a stable and reliable working state, further enhances the gas replenishment effect of the internal compensation system 100, avoids the failure of the shaft end sealing structure due to insufficient gas supply pressure of the internal compensation system 100, improves the overall working stability, reliability and anti-interference ability of the shaft end sealing structure, and ensures that the main shaft extension of the rotating machinery in the supercritical carbon dioxide power generation system can achieve continuous and effective sealing protection.

[0042] In some possible implementations disclosed in this application, see [link to relevant documentation]. Figure 2 As shown, the shaft end sealing structure also includes a leakage recovery system 300; the leakage recovery system 300 is connected to the leakage recovery chamber 2, and the leakage recovery system 300 includes a recovery pipe and a filter device; the filter device is installed on the recovery pipe and is used to filter the isolation gas and impurities, and the leakage recovery system 300 is used to recover the filtered leakage medium to the working medium system.

[0043] In this embodiment, by setting up a leakage recovery system 300 connected to the leakage recovery chamber 2, the leakage medium can be directionally transported through the recovery pipeline. With the help of the filter device set on the recovery pipeline, the isolation gas and various impurities mixed in the leakage medium are effectively filtered, and useless impurities and excess gas in the leakage medium are removed to ensure the cleanliness of the recovered medium. Then, the qualified leakage medium after filtration is uniformly recovered to the working medium system to realize the closed-loop reuse of the leakage medium, further reducing the medium loss of the supercritical carbon dioxide power generation system, improving the overall medium utilization rate of the system, avoiding environmental pollution caused by direct discharge of leakage medium, ensuring the cleanliness and economy of system operation, and preventing impurities from flowing back with the leakage medium and affecting the normal operation of the working medium system. This strengthens the leakage recovery reliability of the entire shaft end sealing structure and further improves the overall operational stability of the supercritical carbon dioxide power generation system.

[0044] It is understood that a recovery channel penetrating the aforementioned sealing seat is provided at a position relative to the leakage recovery chamber 2 to connect to the recovery pipeline of the leakage recovery system 300. The recovery pipeline serves as the carrier for the leakage medium, enabling the directional transport of the leakage medium from the leakage recovery chamber 2 to the working fluid system. The filtration device employs a gas filter, which contains a filter element to purify the leakage medium flowing through the recovery pipeline, removing impurities, particulate matter, and excess isolation gas. This ensures that the filtered medium fully meets the requirements for recovery and reuse by the working fluid system, thereby guaranteeing the safe and stable operation of the system. Here, the working fluid system refers to the aforementioned gas injection system.

[0045] Understandably, during the operation of the shaft end sealing structure, the medium that leaks slightly through the dry gas seal and the isolation gas that leaks a small amount from the isolation gas chamber 3 to the leakage recovery chamber 2 will both collect inside the leakage recovery chamber 2 and then be transported outward through the recovery pipeline connected to it. As it flows through the recovery pipeline, the gas filter installed on the pipeline works simultaneously, using its internal filter element to complete the purification process, thoroughly filtering out impurities, particulate matter, and excess isolation gas mixed in the leaked medium, eliminating useless components that affect the operation of the working fluid system, and ensuring that the cleanliness of the leaked medium meets the standards. The purified, qualified medium will continuously flow back to the working fluid system through the recovery pipeline, completing a closed-loop recycling and reuse process. This process avoids the direct discharge of the leaked medium into the external environment and prevents impurities from flowing back and interfering with the normal operation of the working fluid system, thus steadily improving the medium utilization rate and the overall operational stability of the sealing structure.

[0046] In some possible implementations disclosed in this application, see [link to relevant documentation]. Figure 2 As shown, the shaft end sealing structure also includes an isolation gas system 400; the isolation gas system 400 is connected to the isolation gas chamber 3, and the isolation gas system 400 includes a first isolation gas branch and a second isolation gas branch, with one of the first isolation gas branch being used and the other being a backup; the isolation gas system 400 is used to introduce isolation gas into the isolation gas chamber 3, so that the internal pressure of the isolation gas chamber 3 is higher than the atmospheric pressure and higher than the internal pressure of the leakage recovery chamber 2.

[0047] In this embodiment, an isolation gas system 400 connected to the isolation gas chamber 3 is provided. By coordinating the first isolation gas branch and the second isolation gas branch, which are used and standby respectively, a continuous and stable supply of isolation gas can be achieved. This avoids the interruption of the isolation gas supply due to the failure of a single branch, ensuring that the isolation gas chamber 3 always receives sufficient isolation gas replenishment. This keeps the internal pressure of the isolation gas chamber 3 stable above the atmospheric pressure and above the internal pressure of the leakage recovery chamber 2. This effectively blocks impurities such as air, moisture, and dust from the external environment from entering the sealing structure, and also prevents the medium in the leakage recovery chamber 2 from seeping back into the isolation gas chamber 3. This avoids the medium contaminating the isolation gas chamber 3 or interfering with the normal operation of the isolation gas, further strengthening the external protection capability of the sealing structure, improving the continuity, stability, and reliability of the overall operation of the shaft end sealing structure, and ensuring the continuous and safe operation of the supercritical carbon dioxide power generation system.

[0048] It is understood that two isolation gas channels are respectively opened on the aforementioned sealing seat at positions relative to the isolation gas cavity 3, connecting the first isolation gas branch and the second isolation gas branch respectively. The isolation gas system 400 maintains direct communication with the isolation gas cavity 3 and is composed of the first and second isolation gas branches, operating in a one-in-use, one-out-of-use mode. The first isolation gas branch is used to introduce nitrogen into the isolation gas cavity 3, and the second isolation gas branch is used to introduce compressed air into the isolation gas cavity 3. The operating objective of the isolation gas system 400 is to continuously supply the corresponding isolation gas into the isolation gas cavity 3, regulating the internal pressure of the isolation gas cavity 3 to maintain it above atmospheric pressure and above the internal pressure of the leakage recovery chamber 2, thus strengthening the protective barrier outside the sealing structure.

[0049] Understandably, during the operation of the shaft end sealing structure, the isolation gas system 400 is activated and supplies isolation gas through two branches. During normal operation, one branch is used to stably supply gas, while the other branch is in standby mode. If the branch in use fails or the gas supply is abnormal, the standby branch can be switched on immediately, ensuring that the supply of isolation gas is uninterrupted throughout the process. The continuously supplied isolation gas will form a stable positive pressure inside the isolation gas chamber 3. The pressure difference, which is higher than the atmospheric pressure, will prevent external air, moisture, dust, and other impurities from entering. At the same time, the pressure difference, which is higher than the internal pressure of the leakage recovery chamber 2, will prevent the medium in the leakage recovery chamber 2 from seeping back into the isolation gas chamber 3. This avoids the medium contaminating the internal environment of the isolation gas chamber 3 or interfering with the normal operation of the isolation gas, ensuring that the isolation gas chamber 3 continues to perform its sealing and protective function, and improving the continuity and reliability of the shaft end sealing structure operation.

[0050] Further, see Figure 1 As shown, the isolation gas system 400 also includes an isolation gas recovery hood 401; the isolation gas recovery hood 401 is disposed at one end of the isolation gas chamber 3 near the atmosphere and is used to recover the isolation gas that leaks from the isolation gas chamber 3 to the atmosphere.

[0051] In this embodiment, by setting an isolation gas recovery cover 401 at the end of the isolation gas chamber 3 near the atmosphere, the isolation gas leaking from the isolation gas chamber 3 to the atmosphere can be specifically recovered, avoiding the isolation gas from directly escaping into the external environment and causing resource waste. At the same time, it prevents the escaped isolation gas from affecting the surrounding environment, further improving the overall airtightness of the shaft end sealing structure. Combined with the stable gas supply and positive pressure protection of the isolation gas system 400, a multi-layer protection system is built on the outside of the sealing structure. This not only ensures that the isolation gas chamber 3 can continuously and stably play its core role in blocking external impurities and preventing the reverse infiltration of the medium, but also improves the environmental friendliness and resource utilization rate of the entire shaft end sealing structure, further enhancing the cleanliness and stability of the supercritical carbon dioxide power generation system.

[0052] Understandably, the isolation gas recovery hood 401 is located at the end of the isolation gas chamber 3 closest to the atmosphere, that is, the outermost part of the shaft end sealing structure, adjacent to the atmospheric environment. It wraps around the outermost end of the main shaft and the sealing seat, covering the outlet area of ​​the isolation gas chamber 3 that leaks to the atmosphere, and is used to collect the isolation gas that dissipates from the isolation gas chamber 3 to the atmosphere. Specifically, the isolation gas that leaks into the isolation gas recovery hood 401 can be transported to the isolation gas system 400 for reuse through a pipeline connected to the isolation gas recovery hood 401. Specifically, depending on the system operating conditions, the recovered isolation gas can be directly returned to the isolation gas chamber 3 for use as isolation gas in a cycle, thereby achieving closed-loop recovery and efficient utilization of the isolation gas, further reducing resource consumption and environmental pollution, and improving the resource utilization rate and operating economy of the shaft end sealing structure.

[0053] It will be readily understood by those skilled in the art that the aforementioned advantageous methods can be freely combined and superimposed without conflict.

[0054] 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 shaft end sealing structure, characterized in that, It includes a dry gas sealing chamber, a leakage recovery chamber, and an isolation gas chamber, which are sequentially arranged at both ends of the shaft extension along the direction from the medium side to the atmosphere side; The dry gas sealing cavity is used to install a dry gas seal to prevent media leakage; The leakage recovery chamber is used to collect and recover leaked media; The isolation chamber is used to introduce isolation gas to prevent external gas from entering.

2. The shaft end sealing structure according to claim 1, characterized in that, Also includes: Internal compensation system; The internal replenishment system is connected to the dry gas sealing cavity, and the internal replenishment system includes a first replenishment branch and a second replenishment branch. The first gas replenishment branch is connected to the gas injection system and is used to draw gas from the gas injection system and supply gas to the dry gas sealing cavity in order to establish and maintain the internal pressure of the dry gas sealing cavity higher than the pressure on the medium side, so as to prevent the medium on the medium side from entering the dry gas sealing cavity. The second gas supply branch is connected to the inside of the system and is used to draw gas from the inside of the system and supply gas to the dry gas sealing cavity, so as to establish and maintain the pressure inside the dry gas sealing cavity higher than the pressure on the medium side, and prevent the medium on the medium side from entering the dry gas sealing cavity.

3. The shaft end sealing structure according to claim 2, characterized in that, Also includes: Pressurization system; The pressurization system is connected to the internal compensation system and the dry gas sealing cavity respectively. The pressurization system is used to increase the gas pressure when the output gas pressure of the internal compensation system is insufficient, and to establish a positive pressure difference between the internal pressure of the dry gas sealing cavity and the medium side pressure, so as to prevent the medium on the medium side from entering the dry gas sealing cavity.

4. The shaft end sealing structure according to claim 3, characterized in that, The first and second air supply branches are independent of each other. The first and second air supply branches can be selected to supply air directly to the dry gas sealing cavity, or to supply air to the dry gas sealing cavity after being pressurized by the pressurization system.

5. The shaft end sealing structure according to claim 3, characterized in that, The pressurization system includes a pressurization component, a pressure regulating device, and a gas supply pipeline. The gas supply pipeline connects the pressurization system with the internal compensation system and the dry gas sealing cavity. The pressurization component is installed on the gas supply pipeline to increase the gas pressure entering the dry gas sealing cavity. The pressure regulating device is installed on the gas supply pipeline to regulate and stabilize the gas pressure input to the dry gas sealing cavity after being boosted by the pressurization component, ensuring that the internal pressure of the dry gas sealing cavity is higher than the medium side pressure.

6. The shaft end sealing structure according to claim 1, characterized in that, Also includes: Leakage recovery system; The leakage recovery system is connected to the leakage recovery chamber, and the leakage recovery system includes a recovery pipeline and a filtration device; The filtration device is installed on the recovery pipeline to filter out isolation gas and impurities, and the leakage recovery system is used to recover the filtered leakage medium to the working fluid system.

7. The shaft end sealing structure according to claim 1, characterized in that, Also includes: Isolation gas system; The isolation gas system is connected to the isolation gas cavity. The isolation gas system includes a first isolation gas branch and a second isolation gas branch, with the first isolation gas branch and the second isolation gas branch being used and the other being a backup. The isolation gas system is used to introduce isolation gas into the isolation gas chamber, so that the pressure inside the isolation gas chamber is higher than the atmospheric pressure and higher than the pressure inside the leakage recovery chamber.

8. The shaft end sealing structure according to claim 7, characterized in that, The first isolation gas branch is used to introduce nitrogen, and the second isolation gas branch is used to introduce compressed air.

9. The shaft end sealing structure according to claim 7, characterized in that, The isolation gas system also includes an isolation gas recovery hood; The isolation gas recovery hood is located at one end of the isolation gas cavity near the atmosphere and is used to recover the isolation gas that leaks from the isolation gas cavity to the atmosphere.

10. A supercritical carbon dioxide power generation system, characterized in that, Includes the shaft end sealing structure as described in any one of claims 1-9.

Images