Magnetic suspension air separation expansion machine system and operation method

Abstract

The invention relates to a magnetic suspension air separation expansion machine system and an operation method thereof. The system comprises a base, a magnetic suspension bearing assembly, a rotor assembly and a control module. The magnetic suspension bearing assembly is arranged on the base, comprises an expansion end radial magnetic suspension bearing, a brake end radial magnetic suspension bearing and an axial thrust magnetic suspension bearing, and is used for supporting radial and axial forces of the rotor assembly; the rotor assembly is arranged in the machine body and connected with the machine body through the magnetic suspension bearing assembly, and non-contact suspension is achieved. The control module is electrically connected with the magnetic suspension bearing assembly and used for controlling the magnetic suspension bearing assembly to suspend the rotor. The operation method comprises the steps of self-checking before starting, electrifying to suspend the rotor, starting the air compressor to pressurize, adjusting flow to drive the expansion impeller, carrying out split-flow cooling on gas, and collecting data in real time to maintain stable suspension of the rotor. The device has the advantages of high efficiency, stability, energy conservation and the like and is suitable for the field of air separation.

Description

Technical Field

[0001] The present invention relates to the field of air separation, and particularly to a magnetic levitation air separation expander system and an operation method thereof. Background Art

[0002] At present, most expanders used in domestic and foreign air separation systems and units are mainly hydrodynamic sliding oil film bearings, which belong to high-speed and light-load oil bearings and require complex oil circuit systems and cooling systems. This not only makes the entire air separation system process complex, the pipeline structure cumbersome, and requires the addition of multiple control valves, but also is not conducive to maintenance. During the later maintenance process, the seals at the joints of multiple pipeline flanges will gradually age, causing oil and water leakage and resulting in waste of resources. For air separation units using oil systems, on the one hand, it will cause too high upfront investment costs and increased later maintenance costs, and it is difficult to recover the cost in a short time; on the other hand, the use of oil systems also causes a certain degree of waste of resources. Summary of the Invention

[0003] The purpose of the present invention is to provide a magnetic levitation air separation expander system and an operation method thereof, so as to solve the foregoing problems existing in the prior art.

[0004] In order to achieve the above purpose, the technical solution adopted by the present invention is as follows: A magnetic levitation air separation expander system includes a base; A magnetic levitation bearing assembly is arranged on the base and includes a radial magnetic levitation bearing at the expansion end, a radial magnetic levitation bearing at the braking end, and an axial thrust magnetic levitation bearing. The radial magnetic levitation bearing at the expansion end and the axial thrust magnetic levitation bearing are fixed on the fuselage and correspond to the expansion end AMB rotor assembly and the thrust disc on the rotor assembly respectively, and are used to support the radial and axial forces of the rotor assembly at the expansion end; the radial magnetic levitation bearing at the braking end is fixed on the fuselage and corresponds to the braking end AMB rotor assembly on the rotor assembly, and is used to support the radial force of the rotor assembly at the braking end; A rotor assembly is arranged inside the fuselage and is connected to the fuselage through the magnetic levitation bearing assembly to achieve non-contact suspension; A control module is electrically connected to the magnetic levitation bearing assembly and is used to control the magnetic levitation bearing assembly to make the rotor levitate.

[0005] Further, the rotor assembly includes a main shaft, and an expansion impeller and a braking impeller are respectively connected to both ends thereof; The braking end AMB rotor assembly and the expansion end AMB rotor assembly; are symmetrically arranged at both ends of the main shaft and correspond to the magnetic levitation bearing assembly; The thrust disc is integrally formed with the main shaft and is located in the middle of the main shaft and cooperates with the axial thrust magnetic levitation bearing to balance the axial force of the rotor assembly.

[0006] Further, it further includes: a shaft sealing device which is arranged around the main shaft to form a gas film seal by injecting helium or nitrogen into a sealing gas passage.

[0007] Further, it further includes a heat insulation structure which is arranged between the expansion end and the braking end and is connected to the fuselage and the base; it is used to block the heat conduction between the expansion end and the braking end.

[0008] Further, the rotor assembly further includes auxiliary bearings which are arranged at both ends of the main shaft and are arranged side by side with the magnetic levitation bearing assembly, and are used to provide mechanical support when the magnetic levitation fails or power is cut off.

[0009] Further, both the expansion impeller and the braking impeller adopt a closed three-dimensional impeller structure, and the expansion-end volute and the braking-end volute are physically isolated by the heat insulation structure. The expansion-end volute is connected to a nozzle adjustable mechanism, which is used to adjust the gas flow rate and expansion efficiency according to the real-time gas pressure of the fractionating tower.

[0010] Further, the control module further includes a cooling system which includes a gas shunt pipeline and a liquid nitrogen injection device, and is respectively connected to the expansion-end volute and the braking-end volute, and is used to shunt and cool the expanded low-temperature gas and the pressurized high-temperature gas.

[0011] An operating method of a magnetic levitation air separation expander system based on the same concept includes the following steps: S100. Before starting, the controller performs a self-check on the magnetic levitation bearing assembly to confirm that the sensors and power amplifiers are in normal state; S200. Energize the iron core coil, monitor the rotor suspension position through the displacement sensor, and adjust the current to make the rotor suspend at the set balance point; S300. Start the air compressor, after purifying the compressed air through the molecular sieve, input it into the braking impeller for pressurization through the bellows at the pressurization end inlet; S400. After the pressurized gas is cooled by the cooler, it enters the expansion-end volute, adjusts the flow rate through the nozzle adjustable mechanism, and drives the expansion impeller to output mechanical work externally; S500. The expanded low-temperature gas enters the fractionating tower for rectification, and at the same time, the high-temperature pressurized gas is shunted and cooled through the cooling system; S600. Real-time collect the rotor vibration, temperature and position data, and dynamically adjust the electromagnetic force through the PID closed-loop control algorithm to maintain the stable suspension of the rotor.

[0012] Further, in step S100, the self-check process of the magnetic levitation bearing includes: Execute the zero calibration of the sensor and the gain test of the power amplifier; Generate a self-check report and mark the abnormal channels; Perform no-load current tests on the axial / radial electromagnets to verify the insulation performance of the coils; If the displacement sensor is detected to fail, automatically switch to the standby measurement mode of the eddy current probe; In step S500, the cooling system includes a gas shunt pipeline and a liquid nitrogen injection device, which are respectively connected to the expansion end volute and the braking end volute, and the liquid nitrogen injection volume is controlled in a gradient of 0.1 - 0.3 L / s.

[0013] Furthermore, in step S600, the PID closed-loop control algorithm further includes the following steps: S610. When the pressure fluctuation of the fractionating tower exceeds ±5%, adaptively adjust the proportional coefficient to 1.2 - 1.8; S620. When the rotor vibration frequency exceeds 150 Hz, preferentially reduce the integral time constant to 0.2 seconds; S630. When the cooling efficiency of the liquid nitrogen injection device decreases, trigger the fuzzy control mode to compensate for the electromagnetic force deviation.

[0014] In step S600, the controller adjusts the liquid nitrogen injection volume in real time according to the feedback data of the temperature sensor, and synchronizes with the change of the fractionating tower pressure to ensure the stability of the rectification process.

[0015] The beneficial effects of the present invention are as follows: The present invention relates to a magnetic levitation air separation expansion machine system and its operation method. The present invention adopts a magnetic levitation bearing assembly to achieve non-contact suspension of the rotor, eliminate mechanical friction, improve the operation efficiency and service life of the equipment, and reduce the maintenance cost. An axial seal device and a heat insulation structure are designed to effectively prevent gas leakage and heat conduction, and ensure the stability and safety of the equipment operation. An auxiliary bearing is equipped to provide mechanical support in case of magnetic levitation failure or power failure, enhancing the reliability of the equipment. The expansion impeller and the braking impeller adopt a closed three-dimensional impeller structure, and a nozzle adjustable mechanism is set to adjust the gas flow rate and expansion efficiency according to the working conditions, improving the adaptability and flexibility of the equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 is a schematic structural diagram of the air separation booster expansion machine unit of the magnetic levitation air separation expansion machine system of the present invention; Figure 2 is a schematic structural diagram of the operation of the air separation system of the magnetic levitation air separation expansion machine system of the present invention; Figure 3 is a schematic structural diagram of the air separation magnetic levitation bearing rotor of the magnetic levitation air separation expansion machine system of the present invention.

[0017] In the figure: 1. Expansion impeller; 2. Shaft seal device; 3. Auxiliary bearing; 4. Expansion end radial magnetic levitation bearing; 5. Axial thrust magnetic levitation bearing; 6. Main shaft; 7. Brake end radial magnetic levitation bearing; 8. Brake impeller; 9. Brake end AMB rotor assembly; 10. Expansion end AMB rotor assembly; 101. Expansion end volute; 102. Diffuser; 103. Nozzle adjustment mechanism; 104. Front partition; 105. First heat insulation plate; 106. Base; 107. Second heat insulation plate; 108. Third heat insulation plate; 109. Magnetic levitation bearing rotor; 110. Expansion end shaft seal; 111. Body; 112. Booster end outlet bellows; 113. Booster end shaft seal; 114. Rear partition; 115. Booster end volute; 116. Booster end inlet pipe; 117. Booster end inlet bellows; 201. Suction filter; 202. Air compressor; 203. Cooling tower; 204. Molecular sieve; 205. Fractionating tower; 206. Cooler; 207. Magnetic levitation air separation expansion integrated machine; 208. Magnetic bearing control cabinet. Detailed implementation manners

[0018] In order to make the objectives, technical solutions and advantages of the present invention clearer and more understandable, the present invention will be further described in detail below with reference to the accompanying drawings. It should be understood that the specific implementation manners described herein are only used to explain the present invention and are not used to limit the present invention.

[0019] Refer to Figure 1 、 Figure 2 and Figure 3 A magnetic levitation air separation expander system shown in the figures, comprising a base 106; a magnetic levitation bearing assembly arranged on the base 106, including an expansion end radial magnetic levitation bearing 4, a brake end radial magnetic levitation bearing 7 and an axial thrust magnetic levitation bearing 5, the expansion end radial magnetic levitation bearing 4 and the axial thrust magnetic levitation bearing 5 are fixed on the body 111, corresponding to the expansion end AMB rotor assembly 10 and the thrust disc on the rotor assembly respectively, and are used for supporting the radial and axial forces of the rotor assembly at the expansion end; the brake end radial magnetic levitation bearing 7 is fixed on the body 111, corresponding to the brake end AMB rotor assembly 9 on the rotor assembly, and is used for supporting the radial force of the rotor assembly at the brake end; a rotor assembly arranged inside the body 111, connected to the body 111 through the magnetic levitation bearing assembly to achieve non-contact suspension; a control module electrically connected to the magnetic levitation bearing assembly and used for controlling the magnetic levitation bearing assembly to suspend the rotor.

[0020] In this embodiment, the base 106 serves as the bottom support structure of the entire magnetic levitation air separation expander system, located at the bottom of the entire device, directly in contact with the ground for installation, providing a stable bearing foundation for the device and ensuring the stability of the device during operation.

[0021] The base is the installation carrier of the magnetic levitation bearing assembly. Each bearing in the magnetic levitation bearing assembly is fixed on the base 106 through the fuselage 111. At the same time, the fuselage 111 is connected to the base 106, and the bearing assembly is fixed at the corresponding position of the fuselage; the base 106 plays a role in supporting and fixing the fuselage 111 to ensure the stability and reliability of the fuselage 111.

[0022] The base bears the weights of all components of the entire magnetic levitation air separation expander system and various acting forces generated during operation, such as the centrifugal force of the rotor assembly, gas pressure, etc., to ensure the stability and vibration resistance of the overall structure of the equipment, prevent unstable phenomena such as displacement, tilt or vibration of the equipment during operation, and provide a solid foundation for the long-term stable operation of the equipment.

[0023] The magnetic levitation bearing assembly is arranged on the base 106, distributed at the corresponding positions of the fuselage 111, corresponding to the rotor assembly, and is used to support the rotor assembly and achieve its non-contact suspension. The fuselage 111 is fixedly connected to the base 106. The magnetic levitation bearing assembly interacts with the corresponding components on the rotor assembly through electromagnetic force, so that the rotor assembly realizes non-contact suspension under the support of the magnetic levitation bearing assembly. At the same time, the magnetic levitation bearing assembly is electrically connected to the control module and receives the electrical signals of the control module to adjust the magnitude and direction of the electromagnetic force, so as to accurately control the suspension position and state of the rotor assembly. The magnetic levitation bearing assembly accurately controls the electromagnetic force to enable the rotor assembly to operate stably in the suspended state, avoiding direct contact friction between the traditional mechanical bearing and the rotor, thereby greatly reducing energy loss and component wear, and improving the operation efficiency and service life of the equipment. The expansion end radial magnetic levitation bearing 4 is mainly used to support the radial force of the rotor assembly at the expansion end to ensure the radial stability of the expansion impeller 1 during high-speed rotation; the brake end radial magnetic levitation bearing 7 is used to support the radial force of the rotor assembly at the brake end to ensure the radial balance of the brake impeller 8 during operation; the axial thrust magnetic levitation bearing 5 cooperates with the thrust disk and is used to balance the axial force of the rotor assembly to prevent the rotor assembly from displacing in the axial direction and ensure the axial stability of the rotor assembly, so that the rotor assembly can achieve high-speed, stable and frictionless suspended operation under the precise control of the magnetic levitation bearing assembly.

[0024] The rotor assembly is located inside the fuselage 111 and is the core rotating component of the magnetic levitation air separation expander system, running through the internal space of the entire fuselage 111. The rotor assembly includes a main shaft 6, with an expansion impeller 1 and a braking impeller 8 connected to its two ends respectively. The braking-end AMB rotor assembly 9 and the expansion-end AMB rotor assembly 10 are symmetrically arranged at the two ends of the main shaft 6 and correspond to the braking-end radial magnetic levitation bearing 7, the expansion-end radial magnetic levitation bearing 4, and the axial thrust magnetic levitation bearing 5 in the magnetic levitation bearing assembly respectively, forming a magnetic levitation support structure. The thrust disk is integrally formed with the main shaft 6, located at the middle position of the main shaft 6, and cooperates with the axial thrust magnetic levitation bearing 5. In addition, the shaft sealing device 2 is arranged around the corresponding position of the main shaft 6 to form a sealed gas passage; the heat insulation structure is arranged between the expansion end and the braking end and is connected to the fuselage 111 and the base 106; the auxiliary bearings 3 are arranged at both ends of the main shaft 6 and are arranged side by side with the magnetic levitation bearing assembly to provide mechanical support for the main shaft 6 when magnetic levitation fails or power is cut off. Under the action of the magnetic levitation bearing assembly, non-contact suspension is achieved. When the air compressor 202 sends compressed air into the system, the braking impeller 8 pressurizes the air. The pressurized air enters the expansion-end volute 101 after being cooled by the cooler 206, pushing the expansion impeller 1 to rotate, causing the rotor assembly to start rotating and output mechanical work externally, thereby realizing the expansion and refrigeration process of the air. The main shaft 6, as the main body of the rotor assembly, connects the expansion impeller 1 and the braking impeller 8, transmits the mechanical power between the two, and ensures the coaxiality and balance of the two during operation. The braking-end AMB rotor assembly 9 and the expansion-end AMB rotor assembly 10 interact with the magnetic levitation bearing assembly respectively to provide radial and axial magnetic levitation support forces for the rotor assembly, ensuring the stability and precision of the rotor assembly during high-speed rotation. The thrust disk cooperates with the axial thrust magnetic levitation bearing 5 to balance the axial force generated during the operation of the rotor assembly, prevent the rotor assembly from moving axially, ensure the axial positioning and stable operation of the rotor assembly. The shaft sealing device 2 forms a gas film seal by injecting nitrogen or air, effectively preventing gas leakage inside the fuselage 111, improving the sealing performance of the equipment, reducing cold loss, and at the same time preventing external impurities from entering the inside of the fuselage 111, ensuring internal cleanliness and extending the service life of the equipment. The heat insulation structure blocks the heat conduction between the expansion end and the braking end, prevents unnecessary heat exchange between the low-temperature gas at the expansion end and the high-temperature gas at the braking end, ensures the working temperature environment of the expansion end and the braking end respectively, and improves the thermal efficiency and operation stability of the equipment. The auxiliary bearings 3 can quickly bear the weight of the main shaft 6 in case of emergencies such as the failure of the magnetic levitation system or power cut-off, provide mechanical support for the main shaft 6, avoid collision or damage between the rotor assembly and the fuselage 111, protect the safety of the equipment, and improve the reliability of equipment operation.

[0025] The control module is usually installed outside the fuselage 111 or near the base 106 and is connected to the magnetic levitation bearing assembly through cables or wires to perform real-time control and monitoring of the magnetic levitation bearing assembly. The control module is electrically connected to the magnetic levitation bearing assembly and monitors and controls the working state of the magnetic levitation bearing assembly through components such as sensors and power amplifiers. The control module receives signals from detection elements such as displacement sensors and adjusts the current supplied to the magnetic levitation bearing assembly in real time according to these signals, thereby precisely controlling the electromagnetic force generated by the magnetic levitation bearing assembly and keeping the rotor assembly at the set suspension position and operating state. At the same time, the control module is also connected to other auxiliary systems such as the cooling system to comprehensively control and coordinate the operation of the entire system. The control module is the nerve center of the magnetic levitation air separation expander system, responsible for precisely controlling the magnetic levitation bearing assembly to ensure the stable suspension and reliable operation of the rotor assembly. It dynamically adjusts the magnitude and direction of the electromagnetic force by real-time monitoring parameters such as the position, speed, and vibration of the rotor assembly, using advanced control algorithms such as the PID closed-loop control algorithm, so that the rotor assembly always maintains the best suspension position during operation, avoiding contact or collision between the rotor assembly and the fuselage 111, and ensuring the operation safety and stability of the equipment. In addition, the control module also has a self-check function, which can comprehensively check components such as sensors and power amplifiers of the magnetic levitation bearing assembly before the equipment starts, timely detect and report potential faults or abnormal conditions, and ensure the normal start and operation of the equipment. During operation, the control module can also automatically adjust control parameters according to the actual operating conditions of the system, such as the pressure change of the fractionating column 205 and the rotor vibration frequency, optimize the operating performance of the equipment, and improve the adaptability and flexibility of the equipment.

[0026] Further, the rotor assembly includes a main shaft 6, with an expansion impeller 1 and a braking impeller 8 connected to both ends thereof respectively; a braking-end AMB rotor assembly 9 and an expansion-end AMB rotor assembly 10; symmetrically arranged at both ends of the main shaft 6 and corresponding to the magnetic levitation bearing assembly; a thrust disk integrally formed with the main shaft 6, located in the middle of the main shaft 6, and cooperating with the axial thrust magnetic levitation bearing 5 to balance the axial force of the rotor assembly. It should be noted that the main shaft 6 runs through the inside of the entire fuselage 111 and is the main structural body of the rotor assembly. The main shaft 6 is used to transmit mechanical power between the expansion impeller 1 and the braking impeller 8 and ensure the coaxiality and balance of the two during operation. The strength and rigidity of the main shaft 6 are crucial for the stability and reliability of the rotor assembly.

[0027] The expansion impeller 1 is installed at one end of the main shaft 6 and is located at the expansion end of the fuselage 111. The expansion impeller 1 is connected to the main shaft 6 through a key or bolt to ensure firmness during high-speed rotation. The expansion impeller 1 rotates under the drive of high-pressure gas, converting the internal energy of the gas into mechanical energy to achieve the expansion and refrigeration process of the gas. The blade profile design of the expansion impeller 1 directly affects the gas expansion efficiency and equipment performance.

[0028] The braking impeller 8 is installed at the other end of the main shaft 6, located at the braking end of the fuselage 111. The braking impeller 8 is also connected to the main shaft 6 by a key or bolts to ensure firmness during high-speed rotation. The braking impeller 8 is driven to rotate by pressurized gas, providing the necessary braking and balancing forces for the rotor assembly to ensure the stability of the rotor assembly during operation. The blade profile design of the braking impeller 8 directly affects the gas pressurization efficiency and equipment performance.

[0029] The braking-end AMB rotor assembly 9 and the expansion-end AMB rotor assembly 10 are symmetrically arranged at both ends of the main shaft 6, located at the braking end and the expansion end of the fuselage 111 respectively.

[0030] The braking-end AMB rotor assembly 9 and the expansion-end AMB rotor assembly 10 are fixed on the main shaft 6 through special brackets or connectors, and correspond to the braking-end radial magnetic suspension bearing 7, the expansion-end radial magnetic suspension bearing 4 and the axial thrust magnetic suspension bearing 5 in the magnetic suspension bearing assembly. The braking-end AMB rotor assembly 9 and the expansion-end AMB rotor assembly 10 interact with the magnetic suspension bearing assembly respectively, providing radial and axial magnetic suspension supporting forces for the rotor assembly to ensure the stability and accuracy of the rotor assembly during high-speed rotation.

[0031] The thrust disk is integrally formed with the main shaft 6 and is located at the middle position of the main shaft 6. The thrust disk cooperates with the axial thrust magnetic suspension bearing 5 to form an axial magnetic suspension support. The thrust disk is used to balance the axial force generated during the operation of the rotor assembly, prevent the rotor assembly from moving axially, and ensure the axial stability of the rotor assembly. The surface flatness and accuracy of the thrust disk have an important impact on the performance of the axial thrust magnetic suspension bearing 5.

[0032] The rotor assembly realizes non-contact suspension through the magnetic suspension bearing assembly, and its working principle is as follows: Magnetic suspension support principle: The magnetic suspension bearing assembly suspends the rotor assembly through electromagnetic force, avoiding direct contact friction between the traditional mechanical bearing and the rotor. The expansion-end radial magnetic suspension bearing 4, the braking-end radial magnetic suspension bearing 7 and the axial thrust magnetic suspension bearing 5 respectively provide radial and axial electromagnetic forces to offset the gravity and gas acting forces of the rotor assembly, enabling the rotor assembly to operate stably in a suspended state.

[0033] The control module real-time monitors parameters such as the position, speed and vibration of the rotor assembly, and dynamically adjusts the magnitude and direction of the electromagnetic force through the PID closed-loop control algorithm to ensure that the rotor assembly always maintains at the set suspension position.

[0034] Principle of gas expansion and pressurization: When the air compressor 202 sends compressed air into the system, the compressed air first enters the braking impeller 8 and is further pressurized under the action of the braking impeller 8. The pressurized gas enters the expansion end volute 101 after being cooled by the cooler 206, and then the flow rate and velocity are adjusted through the nozzle adjustable mechanism 103 to impact the expansion impeller 1, driving the expansion impeller 1 to rotate and output mechanical work externally.

[0035] The expansion impeller 1 converts the internal energy of the gas into mechanical energy, realizing the expansion and refrigeration process of the gas. The expanded low-temperature gas enters the fractionating tower 205 for rectification separation to obtain gas products with different purities.

[0036] Principle of axial force balance: During the gas expansion and pressurization process, the rotor assembly is subjected to axial force. The thrust disk cooperates with the axial thrust magnetic suspension bearing 5 to balance the axial force of the rotor assembly through electromagnetic force, preventing the rotor assembly from moving axially.

[0037] The control module dynamically adjusts the electromagnetic force of the axial thrust magnetic suspension bearing 5 by real-time monitoring of the axial position of the rotor assembly to ensure the axial stability of the rotor assembly.

[0038] Furthermore, it also includes: a shaft sealing device 2, which is provided with a sealed gas channel surrounding the main shaft 6 and forms a gas film seal by injecting helium or nitrogen.

[0039] In this embodiment, the shaft sealing device 2 surrounds the sealed gas channel of the main shaft 6, is located inside the fuselage 111 and closely cooperates with the main shaft 6. The sealed gas channel of the shaft sealing device 2 is connected to an external helium or nitrogen supply system, and helium or nitrogen is introduced into the sealed gas channel through special pipelines and valves. When helium or nitrogen is injected into the sealed gas channel, a gas film will be formed at the gap between the main shaft 6 and the fuselage 111. This gas film can effectively prevent the gas inside the fuselage 111 from leaking to the external environment, and at the same time prevent external air, impurities, etc. from entering the inside of the fuselage 111, ensuring the purity and cleanliness of the internal gas, improving the sealing performance of the equipment, reducing cold loss, and extending the service life of the equipment.

[0040] Furthermore, it also includes a heat insulation structure, which is arranged between the expansion end and the braking end and is connected to the fuselage 111 and the base 106; it is used to block the heat conduction between the expansion end and the braking end.

[0041] The heat insulation structure is arranged between the expansion end and the braking end, connected to the fuselage 111 and the base 106, and surrounds the corresponding part of the fuselage 111. The heat insulation structure is connected to the fuselage 111 and the base 106 through special connecting parts or fixing devices, forming a relatively closed heat insulation layer, which isolates the expansion end and the braking end to a certain extent. The expansion end generates low temperature during the gas expansion process, while the braking end generates high temperature during the gas pressurization process. The heat insulation structure can effectively block the heat conduction between the expansion end and the braking end, prevent the high-temperature gas from conducting heat to the low-temperature area, avoid unnecessary heat exchange between the low-temperature gas and the high-temperature gas, ensure the working temperature environment of the expansion end and the braking end respectively, improve the thermal efficiency and operation stability of the equipment, reduce energy loss, and ensure the normal operation of the equipment.

[0042] It should be further noted that the heat insulation structure mainly includes the following parts: the first heat insulation plate 105, the second heat insulation plate 107, the third heat insulation plate 108 and the heat insulation cover. The following is a detailed description of each structure: The first heat insulation plate 105 is installed between the expansion end volute 101 and the fuselage 111, close to the expansion end. The first heat insulation plate 105 is fixed on the inner wall of the fuselage 111 through connecting parts such as bolts, located at the outlet of the expansion end volute 101, and is in close contact with the expansion end volute 101.

[0043] The second heat insulation plate 107 is installed inside the fuselage 111, between the expansion end and the braking end. The second heat insulation plate 107 is fixed on the inner wall of the fuselage 111 through special brackets or connecting parts, forming a heat insulation barrier, which isolates the expansion end and the braking end to a certain extent.

[0044] The third heat insulation plate 108 is installed between the braking end volute and the fuselage 111, close to the braking end. The third heat insulation plate 108 is fixed on the inner wall of the fuselage 111 through connecting parts such as bolts, located at the inlet of the braking end volute, and is in close contact with the braking end volute.

[0045] The heat insulation cover is arranged outside the fuselage 111, covering the corresponding part of the fuselage 111. The heat insulation cover is fixed on the outer wall of the fuselage 111 through connecting parts such as buckles or bolts, forming an external heat insulation layer, which further reduces the heat dissipation and the intrusion of external heat. These heat insulation structures cooperate with each other, effectively blocking the heat conduction between the expansion end and the braking end, preventing the high-temperature gas from conducting heat to the low-temperature area, avoiding unnecessary heat exchange between the low-temperature gas and the high-temperature gas, and ensuring the normal operation and thermal efficiency of the equipment.

[0046] Furthermore, the rotor assembly further includes auxiliary bearings 3, which are arranged at both ends of the main shaft 6 and arranged side by side with the magnetic levitation bearing assembly, and are used to provide mechanical support when the magnetic levitation fails or the power is cut off.

[0047] The auxiliary bearings 3 are arranged at both ends of the main shaft 6, arranged side by side with the magnetic levitation bearing assembly, located inside the fuselage 111 and close to both ends of the main shaft 6. The auxiliary bearings 3 are installed on the fuselage 111 through special brackets or fixing parts. Both ends of the main shaft 6 are respectively inserted into the bearing holes of the auxiliary bearings 3, and a certain fitting clearance is maintained between them.

[0048] During normal operation, the rotor assembly realizes contactless suspension under the action of the magnetic levitation bearing assembly, and the auxiliary bearings 3 do not participate in the support. However, when the magnetic levitation system fails or loses power, the auxiliary bearings 3 can quickly support the main shaft 6, provide mechanical support for the main shaft 6, prevent the rotor assembly from colliding with or damaging the fuselage 111, protect the safety of the equipment, and improve the reliability of the equipment operation.

[0049] Furthermore, both the expansion impeller 1 and the braking impeller 8 adopt a closed three-dimensional impeller structure, and the expansion-end volute 101 and the braking-end volute are physically isolated by a heat insulation structure. The expansion-end volute 101 is connected to the nozzle adjustable mechanism 103, which is used to adjust the gas flow rate and expansion efficiency according to the real-time gas pressure of the fractionating tower 205.

[0050] The expansion impeller 1 is located at the expansion end of the fuselage 111, and the braking impeller 8 is located at the braking end of the fuselage 111. They are respectively installed at both ends of the main shaft 6.

[0051] The expansion impeller 1 and the braking impeller 8 are respectively connected to the main shaft 6 through keys or bolts to form a whole, ensuring firmness and synchronism during high-speed rotation. The expansion-end volute 101 cooperates with the expansion impeller 1, and the braking-end volute cooperates with the braking impeller 8. The expansion-end volute 101 and the braking-end volute are physically isolated by a heat insulation structure. The expansion-end volute 101 is also connected to the nozzle adjustable mechanism 103, and the nozzle adjustable mechanism 103 is connected to the external gas supply system through pipelines and valves.

[0052] The closed three-dimensional impeller structure has high aerodynamic performance and efficiency. The expansion impeller 1 rotates under the impact of high-pressure gas, converting the internal energy of the gas into mechanical energy to realize the expansion and refrigeration process of the gas. The braking impeller 8 rotates by the push of the pressurized gas, providing the necessary braking and balance force for the rotor assembly. The expansion-end volute 101 and the braking-end volute respectively collect and guide the gas flow, ensuring reasonable gas flow velocity and pressure distribution in the impeller. The physical isolation of the heat insulation structure prevents thermal interference between the expansion end and the braking end, ensuring their respective aerodynamic performance. The nozzle adjustable mechanism 103 can adjust the gas flow rate and expansion efficiency according to the real-time gas pressure of the fractionating tower 205, adjust the gas flow velocity and flow rate by changing the opening of the nozzle, thereby optimizing the working state of the expansion impeller 1 and improving the adaptability and flexibility of the equipment.

[0053] Further, the control module further includes a cooling system, which comprises a gas shunt pipeline and a liquid nitrogen injection device, respectively connected to the expansion end volute 101 and the brake end volute, for shunt-cooling the expanded low-temperature gas and the pressurized high-temperature gas.

[0054] The cooling system comprises a gas shunt pipeline and a liquid nitrogen injection device. The gas shunt pipeline is respectively connected to the expansion end volute 101 and the brake end volute. The liquid nitrogen injection device is installed at corresponding positions for injecting liquid nitrogen into the high-temperature area. The gas shunt pipeline is connected to the expansion end volute 101 and the brake end volute, guiding the expanded low-temperature gas and the pressurized high-temperature gas to different cooling paths respectively. The liquid nitrogen injection device is connected to the liquid nitrogen supply source through a pipeline and injects liquid nitrogen into the high-temperature area according to the set control signal.

[0055] The cooling system shunt-cools the expanded low-temperature gas and the pressurized high-temperature gas. For the low-temperature gas, it is guided to subsequent processing links through the gas shunt pipeline to avoid adverse effects of supercooled gas on the equipment. For the high-temperature gas, the liquid nitrogen injection device controls the injection volume of liquid nitrogen in a graded manner according to the set flow rate gradient of 0.1 - 0.3 L / s, quickly cools the high-temperature gas, prevents the gas temperature from being too high and having adverse effects on the equipment and subsequent processes, ensures the safe operation of the equipment, and also helps to improve the thermal efficiency and stability of the entire system.

[0056] Furthermore, the system further includes: a diffuser 102, a front partition 104, a magnetic suspension bearing rotor 109, an expansion end shaft seal 110, a booster end outlet bellows 112, a booster end shaft seal 113, a rear partition 114, a booster end volute 115, a booster end inlet pipe 116, a booster end inlet bellows 117, a suction filter 201, a cooling tower 203, a magnetic suspension air separation expansion integrated machine 207, and a magnetic bearing control cabinet 208; The diffuser 102 is installed at the outlet of the brake impeller 8 and is located at the brake end of the fuselage 111. It is in the fluid passage between the brake impeller 8 and the fuselage 111, surrounding the brake impeller 8, and is the next component that the gas enters after flowing out of the brake impeller 8.

[0057] The diffuser 102 is respectively connected to the outlet of the brake impeller 8 and the subsequent cooler 206 through its inlet and outlet pipelines to form a gas flow channel. The outer shell of the diffuser 102 is fixedly connected to the fuselage 111, and its internal structures such as blades correspond to those of the brake impeller 8 to guide and regulate the gas flow.

[0058] After the gas flows out of the braking impeller 8 at a high speed, it enters the diffuser 102. The channel of the diffuser 102 is designed to be divergent, so that the flow velocity of the gas gradually decreases when flowing through it, thereby converting part of the kinetic energy of the gas into pressure energy and increasing the pressure of the gas. By reasonably designing the blade shape and arrangement of the diffuser 102, the vortex and separation phenomena of the gas during the flow process can be effectively reduced, the total pressure loss can be reduced, and the gas transportation efficiency can be improved. The structure of the diffuser 102 can rectify the high-speed and uneven air flow coming out of the braking impeller 8, making it a relatively stable and uniform air flow, providing good intake conditions for subsequent equipment such as the cooler 206, and ensuring the stable operation of the entire system.

[0059] The front partition 104 belongs to a part of the expansion end volute 101 and is a separating component in the volute structure. It is located at the front end of the expansion end volute 101, near the inlet of the expansion impeller 1, and is installed inside the fuselage 111. The front partition 104 is fixed to the front end of the expansion end volute 101 through connecting parts such as bolts, forms an integral body with the expansion end volute 101, and jointly constitutes the gas flow channel. It is mainly used to guide the gas at the outlet of the expansion impeller 1 into the main channel of the expansion end volute 101, ensure that the gas can flow into the subsequent flow channels evenly and smoothly, reduce the loss of gas flow, improve the gas collection efficiency, and optimize the aerodynamic performance of the expansion end volute 101.

[0060] The magnetic suspension bearing rotor 109 belongs to a part of the magnetic suspension bearing assembly and is the rotor component corresponding to the magnetic suspension bearing. It is located at both ends of the main shaft 6, corresponding to the positions of the magnetic suspension bearings at the expansion end and the braking end respectively, and is installed on the main shaft 6. The magnetic suspension bearing rotor 109 and the main shaft 6 are fixed together by connection methods such as keys or bolts and rotate together with the main shaft 6. At the same time, the magnetic suspension bearing rotor 109 corresponds to the magnetic suspension bearing assembly (such as the expansion end radial magnetic suspension bearing 4, the braking end radial magnetic suspension bearing 7, etc.) to form a magnetic suspension support structure.

[0061] Under the action of the electromagnetic force generated by the magnetic suspension bearing assembly, the magnetic suspension bearing rotor 109 enables the main shaft 6 and the rotor assembly to achieve non-contact suspension, avoiding the direct contact friction between the traditional mechanical bearing and the rotor, thereby reducing energy loss and component wear, improving the operation efficiency and service life of the equipment, and ensuring the stable suspension and reliable operation of the rotor assembly.

[0062] The expansion end shaft seal 110 belongs to a part of the shaft sealing device 2 and is used to seal the shaft part at the expansion end. It is installed at the connection between the main shaft 6 at the expansion end and the fuselage 111, located at the expansion end of the fuselage 111. The expansion end shaft seal 110 is closely fitted with the fuselage 111 and the main shaft 6 through sealing elements such as sealing rings or gaskets to form a sealed chamber.

[0063] Effectively prevent the low-temperature gas at the expansion end from leaking along the main shaft 6 to the external environment, and at the same time prevent external air and impurities from entering the interior of the fuselage 111, ensure the purity and pressure stability of the gas inside the expansion end, reduce cold loss, and maintain the normal operation and efficiency of the equipment.

[0064] The bellows 112 at the outlet of the supercharging end is part of the outlet pipeline of the supercharging end and has the functions of compensating for the thermal expansion of the pipeline and absorbing vibration. It is installed on the outlet pipeline of the supercharging end, in the pipeline system after the outlet of the braking impeller 8, and near the outlet of the supercharging end of the fuselage 111. The bellows 112 at the outlet of the supercharging end is connected to the outlet pipeline of the supercharging end through connectors such as flanges to form a telescopic connection section. Since the temperature change during the gas supercharging process may cause the thermal expansion of the pipeline, the elastic structure of the bellows can compensate for this thermal expansion and prevent the pipeline from being damaged due to thermal stress. At the same time, the bellows can also absorb the vibration and noise in the pipeline system, reduce the impact on the equipment and buildings, and improve the stability and reliability of the system.

[0065] The shaft seal 113 at the supercharging end is part of the shaft sealing device 2 and is used to seal the shaft part of the supercharging end. It is installed at the connection between the main shaft 6 of the supercharging end and the fuselage 111, at the supercharging end of the fuselage 111. The shaft seal 113 at the supercharging end is closely fitted with the fuselage 111 and the main shaft 6 through sealing elements such as sealing rings or gaskets to form a sealed chamber. Prevent the high-temperature gas after supercharging from leaking along the main shaft 6 to the outside, avoid energy loss and thermal pollution to the environment, and at the same time prevent external air and impurities from entering the interior of the fuselage 111, ensure the pressure and temperature stability of the gas inside the supercharging end, and ensure the normal operation and performance of the equipment.

[0066] The rear baffle 114 is a separating component in the volute structure. It is located at the rear end of the volute at the braking end, near the outlet of the braking impeller 8, and is installed inside the fuselage 111. The rear baffle 114 is fixed to the rear end of the volute at the braking end through connectors such as bolts to form an integral body with the volute at the braking end, and together they form the gas flow channel. It is mainly used to guide the gas at the outlet of the braking impeller 8 into the main channel of the volute at the braking end, so that the gas can flow out of the volute evenly and stably, reduce the loss of gas flow and the eddy current phenomenon, and improve the aerodynamic performance and gas collection efficiency of the volute at the braking end.

[0067] The supercharging end volute 115 belongs to the braking end component of the magnetic levitation air separation expander and is an important part of the gas supercharging system. It is installed at the braking end of the fuselage 111, surrounds the periphery of the braking impeller 8, and forms a gas collection and export channel. The supercharging end volute 115 is fixedly connected to the fuselage 111 through connectors such as flanges, corresponds to the outlet of the braking impeller 8, and constitutes a gas flow channel. At the same time, the outlet of the supercharging end volute 115 is connected to subsequent equipment such as the cooler 206 through a pipeline. It collects the supercharged gas discharged from the braking impeller 8 and guides it to the subsequent cooling system for cooling. The special shape of the supercharging end volute 115 can gradually reduce the speed of the gas after it flows out of the braking impeller 8, convert part of the kinetic energy into pressure energy, increase the pressure of the gas, and at the same time reduce the loss of gas flow, ensuring the stable transmission of the gas.

[0068] The supercharging end inlet pipe 116 belongs to the air intake system of the magnetic levitation air separation expander and is a channel for introducing the purified compressed air into the braking impeller 8. It is installed at the braking end of the fuselage 111, one end is connected to the outlet of the molecular sieve 204, and the other end is connected to the supercharging end inlet bellows 117 and is located outside the fuselage 111. The supercharging end inlet pipe 116 is connected to the outlet of the molecular sieve 204 and the supercharging end inlet bellows 117 through connectors such as flanges to form a complete air intake pipeline. It stably and evenly transports the compressed air purified by the molecular sieve 204 to the supercharging end inlet bellows 117, and then introduces it into the braking impeller 8 for supercharging. The design of the supercharging end inlet pipe 116 should ensure smooth gas flow, reduce pressure loss, and ensure that the braking impeller 8 can obtain sufficient and stable air intake.

[0069] The supercharging end inlet bellows 117 belongs to the air intake system of the magnetic levitation air separation expander and is a flexible pipeline connecting the supercharging end inlet pipe 116 and the braking impeller 8. It is installed at the braking end of the fuselage 111, one end is connected to the supercharging end inlet pipe 116, and the other end extends into the interior of the fuselage 111 and is connected to the inlet of the braking impeller 8. The supercharging end inlet bellows 117 is connected to the supercharging end inlet pipe 116 through connectors such as flanges, and the other end is connected to the inlet of the braking impeller 8 inside the fuselage 111 through a sealing device to form a displacement-compensating air intake channel. Due to displacements caused by reasons such as thermal expansion and vibration of the fuselage 111 and the pipeline system, the flexible structure of the supercharging end inlet bellows 117 can compensate for these displacements, ensuring the airtightness and stability of the air intake. At the same time, it can also absorb part of the pipeline vibration, reduce the impact on the equipment and the building, ensure that the gas can stably and evenly enter the braking impeller 8, and provide reliable air intake conditions for the supercharging process.

[0070] The intake filter 201 is a filtering device for air before it enters the compressor. It is installed at the air inlet of the air compressor 202, usually at the front end or the top of the air compressor 202, and is at the very front end of the entire magnetic levitation air separation expander system. The intake filter 201 is connected to the air inlet of the air compressor 202 by means such as flange or threaded connection to form a passage for air to enter the compressor. It filters the air entering the air compressor 202, removing pollutants such as dust, impurities, and oil mist in the air, and ensuring the air quality entering the compressor. Clean air helps improve the compression efficiency of the air compressor 202, reduce the wear inside the compressor, extend the service life of the equipment, and is also beneficial to the subsequent air separation process, avoiding adverse effects of impurities on the entire system.

[0071] The cooling tower 203 belongs to the cooling system of the magnetic levitation air separation expander and is a device for cooling high-temperature gases. It is usually installed outside the magnetic levitation air separation expander system, close to the equipment or pipelines that need to be cooled, such as the position of the outlet pipeline of the boosting end or the cooler 206, etc., to facilitate the circulation and heat dissipation of the cooling medium. The cooling tower 203 is connected to the cooler 206 or the outlet pipeline of the boosting end through pipelines to form a circulating cooling system. The cooling medium such as water circulates between the cooling tower 203 and the cooler 206, taking away the heat of the high-temperature gas. After the high-temperature gas is discharged from the volute 115 of the boosting end, it enters the cooler 206 for preliminary cooling. The cooling medium in the cooler 206 absorbs the heat of the gas and its temperature rises. Subsequently, these high-temperature cooling media are pumped to the cooling tower 203. In the cooling tower 203, the cooling medium exchanges heat with the outside air and dissipates the heat into the atmosphere, thereby reducing the temperature of the cooling medium. The cooled medium then circulates back to the cooler 206 to continue cooling the high-temperature gas. This cycle repeats to ensure that the gas can be fully cooled, meet the temperature requirements of the subsequent expansion process and rectification process, and ensure the stable operation of the entire system.

[0072] The magnetic levitation air separation and expansion integrated machine 207 is an integrated device of the entire magnetic levitation air separation expander system, which includes the above-mentioned magnetic levitation air separation expander unit and related auxiliary systems.

[0073] As the main equipment of the entire system, the magnetic levitation air separation and expansion integrated machine 207 is usually installed in the air separation workshop or the designated process area, placed on a solid and flat foundation, with sufficient space for operation and maintenance around it. The magnetic levitation air separation and expansion integrated machine 207 internally integrates components such as the fuselage 111, rotor assembly, magnetic levitation bearing assembly, control module, shaft seal device 2, heat insulation structure, auxiliary bearing 3, expansion end volute 101, boosting end volute 115, and various pipelines and valves. Its inlet and outlet pipelines are respectively connected to external equipment such as the air compressor 202, molecular sieve 204, and fractionating tower 205 to form a complete air separation process flow.

[0074] The magnetic levitation air separation expansion integrated machine 207 is the core equipment for realizing air separation. Through magnetic levitation technology, the rotor assembly is suspended without contact and rotates at high speed. The expansion impeller 1 and the braking impeller 8 are used to expand and refrigerate air and pressurize air respectively, providing a low-temperature environment for the fractionating tower 205 to realize the rectification separation of air and produce high-purity gas products such as oxygen and nitrogen. It integrates the magnetic levitation air separation expansion machine unit and its auxiliary systems to form a compact, efficient and stable operating system, which is convenient for installation, operation and maintenance, and improves the efficiency and reliability of the entire air separation process.

[0075] The magnetic bearing control cabinet 208 belongs to the electrical control system of the magnetic levitation air separation expansion machine system and is the core component for controlling the magnetic levitation bearing assembly and other related equipment. It is usually installed near the magnetic levitation air separation expansion integrated machine 207, placed on the special control cabinet foundation in the control room or equipment room, and is connected to each component in the magnetic levitation air separation expansion integrated machine 207 through cables. The magnetic bearing control cabinet 208 is connected to the magnetic levitation bearing assembly (including the expansion end radial magnetic levitation bearing 4, the braking end radial magnetic levitation bearing 7, the axial thrust magnetic levitation bearing 5, etc.), sensors, power amplifiers, cooling systems, shaft seal devices 2 and other components in the magnetic levitation air separation expansion integrated machine 207 through power cables and signal cables to form a complete control system network. The magnetic bearing control cabinet 208 is the nerve center of the entire magnetic levitation air separation expansion machine system, responsible for precisely controlling and monitoring the magnetic levitation bearing assembly to ensure the stable suspension and reliable operation of the rotor assembly. It calculates and outputs control signals by using advanced control algorithms (such as the PID closed-loop control algorithm) through real-time acquisition of various parameters fed back by sensors (such as displacement sensors, temperature sensors, vibration sensors, etc.) to adjust the magnitude and direction of the electromagnetic force in the magnetic levitation bearing assembly, so that the rotor assembly always maintains the best suspension position. At the same time, the magnetic bearing control cabinet 208 also has self-checking functions, fault diagnosis functions and protection functions. It can comprehensively check the system before the equipment starts, detect and report faults in time, monitor the equipment status in real time during operation, and immediately take corresponding protection measures such as emergency stop and switching to the standby system once an abnormal situation occurs to ensure the safety of the equipment and personnel and guarantee the stable and efficient operation of the magnetic levitation air separation expansion machine system.

[0076] An operating method for a magnetic levitation air separation expansion machine system based on the same concept includes the following steps: S100. Before starting, the controller performs self-checking on the magnetic levitation bearing assembly to confirm that the sensors and power amplifiers are in normal states.

[0077] Specifically in this step: Controller initialization: Start the control system, power on the controller and perform initialization configuration, and load the preset control parameters and self-checking programs.

[0078] Magnetic levitation bearing assembly inspection: The controller sends a self-check command to the magnetic levitation bearing assembly to activate the self-check functions of the expansion-end radial magnetic levitation bearing 4, the braking-end radial magnetic levitation bearing 7, and the axial thrust magnetic levitation bearing 5.

[0079] Sensor calibration and testing: The system automatically calibrates the displacement sensor to ensure that it can accurately measure the position changes of the rotor assembly. At the same time, the sensitivity and response speed of the sensor are tested to verify whether it is within the normal operating range.

[0080] Power amplifier gain testing: The controller adjusts the output signal of the power amplifier to test its amplification ability and stability for the input control signal, ensuring that the power amplifier can provide precise current control for the electromagnetic coils.

[0081] Self-check report generation and anomaly marking: Based on the test results of each item, the controller generates a self-check report, detailing the self-check status of each component. The detected abnormal channels are marked to remind the maintenance personnel to conduct inspections and repairs.

[0082] No-load current testing of the electromagnet: Conduct no-load current testing on the axial / radial electromagnets. By detecting the current value of the electromagnet under no-load conditions, verify the insulation performance of the coil and whether there are faults such as short circuits in the winding.

[0083] Preparation for switching to the standby measurement mode: If the displacement sensor is detected to be faulty, the controller automatically switches to the eddy current probe standby measurement mode to ensure that the system can still obtain the rotor position information and maintain the basic levitation control function in case of sensor failure.

[0084] S200. Energize the iron core coil, monitor the rotor levitation position through the displacement sensor, and adjust the current to make the rotor levitate at the set balance point.

[0085] Specifically in this step: During the startup process of the magnetic levitation air separation expansion machine system, the controller first calculates the initial current value based on the self-check results and the preset levitation position parameters, energizes the iron core coil of the magnetic levitation bearing assembly to generate an initial electromagnetic force. The displacement sensor continuously monitors the position of the rotor assembly and feeds the data back to the controller. The controller uses the PID control algorithm to accurately adjust the electromagnet current according to the comparison result between the feedback data and the set balance point position, making the rotor assembly gradually approach and finally stably levitate at the set balance point, ensuring that the levitation position deviation is extremely small and guaranteeing the stability and operation accuracy of the rotor assembly.

[0086] S300. Start the air compressor 202. After purifying the compressed air through the molecular sieve 204, input it through the booster-end inlet bellows 117 to boost the braking impeller 8.

[0087] The specific operations in this step are as follows: During the operation of the magnetic levitation air separation expander system, after starting the air compressor 202, the motor drives the compressor rotor to rotate, sucking air from the suction filter 201, and gradually compressing it in the compression chamber to increase the pressure and density of the air. At the same time, the air temperature will also rise. Subsequently, the compressed air enters the molecular sieve 204 through the pipeline, and uses its pore structure to adsorb and separate impurities such as moisture, carbon dioxide, and hydrocarbons, realizing the drying and purification of the air. Finally, the purified compressed air is input into the braking impeller 8 through the bellows 117 at the booster end. The flexible structure of the bellows can compensate for the small displacements and vibrations of the pipeline, ensuring that the gas enters the braking impeller 8 stably and evenly for the next stage of boosting.

[0088] S400. After the boosting gas is cooled by the cooler 206, it enters the volute 101 at the expansion end, and the flow rate is adjusted by the nozzle adjustable mechanism 103 to drive the expansion impeller 1 to output mechanical work externally.

[0089] The specific operations in this step are as follows: During the operation of the magnetic levitation air separation expander system, the braking impeller 8 rotates at high speed to generate centrifugal force, further accelerating and compressing the incoming compressed air, significantly increasing its pressure and temperature and then discharging it evenly. Subsequently, the high-temperature gas enters the cooler 206 and exchanges heat with the cooling medium. The heat is absorbed and carried away, the gas temperature decreases, and part of the moisture may condense and be discharged. The cooled gas flows into the volute 101 at the expansion end, and its geometric shape guides the gas to the inlet of the expansion impeller 1. While the flow rate decreases, part of the pressure energy is converted into kinetic energy, providing power for the rotation of the expansion impeller 1. The nozzle adjustable mechanism 103 automatically adjusts the nozzle opening according to the real-time pressure of the fractionating tower 205 and the system operating conditions, controlling the gas flow rate and velocity to ensure the stable output of mechanical work by the expansion impeller 1.

[0090] S500. The expanded low-temperature gas enters the fractionating tower 205 for rectification, and at the same time, the high-temperature boosting gas is shunted and cooled through the cooling system.

[0091] The specific operations in this step are as follows: The expanded low-temperature gas enters the fractionating tower 205, exchanges heat and mass transfer with the rising steam to achieve rectification separation, producing high-purity oxygen, nitrogen, etc. At the same time, the high-temperature boosting gas enters the cooler 206 and the liquid nitrogen injection device through the shunt pipeline for cooling. The liquid nitrogen injection device controls the liquid nitrogen injection volume according to the flow rate gradient of 0.1 - 0.3 L / s, quickly vaporizing and absorbing heat to reduce the gas temperature. The cooling system coordinates the work of each device according to the gas temperature and flow rate to ensure sufficient cooling and avoid energy waste and equipment icing.

[0092] S600. Real-time collect the rotor vibration, temperature, and position data, and dynamically adjust the electromagnetic force through the PID closed-loop control algorithm to maintain the stable suspension of the rotor.

[0093] The specific operations in this step are as follows: The vibration sensor, temperature sensor, and displacement sensor installed on the rotor assembly collect the vibration amplitude, frequency, temperature, and position data of the rotor in real time, and transmit the data to the controller through wired or wireless communication methods. After receiving the sensor data, the controller immediately compares the rotor position data with the set equilibrium position, calculates the current change amount through the PID closed-loop control algorithm, quickly adjusts the electromagnet current, precisely changes the electromagnetic force, corrects the position deviation, and ensures the stable suspension of the rotor. When the pressure fluctuation of the fractionating tower 205 exceeds ±5% or the rotor vibration frequency exceeds 150 Hz, the controller adaptively adjusts the proportional coefficient or reduces the integral time constant to enhance the system stability. If the cooling efficiency of the liquid nitrogen injection device decreases, the fuzzy control mode is triggered to compensate for the deviation. At the same time, the controller adjusts the liquid nitrogen injection amount according to the feedback of the temperature sensor, synchronously with the pressure change of the fractionating tower, to ensure the stability of the rectification process.

[0094] Further, in step S100, the self-check process of the magnetic levitation bearing includes: performing zero calibration of the sensor and gain test of the power amplifier.

[0095] The system first performs zero calibration on the displacement sensor. Through specific algorithms and operation procedures, the output signal of the sensor is adjusted to the reference value corresponding to the actual zero position of the rotor assembly to ensure its accurate measurement of the rotor position. At the same time, the system performs a gain test on the power amplifier. A control signal with a known amplitude is input, and its output current or voltage is measured to verify whether the amplification factor meets the design requirements to ensure accurate current control for the electromagnet.

[0096] Generate a self-check report and mark the abnormal channels; After completing all tests, the controller generates a detailed self-check report according to the test results. The report records the test data of each tested component, whether it passes the test, and other information. For the channels that fail the test, the system will automatically mark them as abnormal so that maintenance personnel can quickly locate the problem and conduct inspections and repairs in a timely manner.

[0097] Conduct no-load current tests on the axial / radial electromagnets to verify the insulation performance of the coils; The system conducts no-load current tests on the axial and radial electromagnets respectively. Under no-load conditions, a certain current is passed through the electromagnet coil, and the current value at this time is measured. By comparing with the design value or historical data, it is judged whether there are problems such as short circuit, open circuit, or decreased insulation performance in the electromagnet coil. If the current value exceeds the allowable range, it indicates that the electromagnet may have a fault and further troubleshooting and handling are required.

[0098] If it is detected that the displacement sensor fails, automatically switch to the eddy current probe standby measurement mode.

[0099] During the self-check process, if the displacement sensor is detected to fail, the system will automatically switch to the eddy current probe backup measurement mode. The eddy current probe is a non-contact sensor based on the principle of electromagnetic induction. It can measure the distance between the rotor assembly and the sensor, thereby indirectly measuring the position of the rotor. Although this backup mode may be slightly inferior to the displacement sensor in terms of accuracy and stability, when the displacement sensor fails, it can still provide the necessary position information for the system, maintain the basic suspension control function, and ensure the safety and reliability of the system.

[0100] In step S500, the cooling system includes a gas shunt pipeline and a liquid nitrogen injection device, which are respectively connected to the expansion end volute 101 and the braking end volute, and the liquid nitrogen injection volume is controlled in a gradient of 0.1 - 0.3 L / s.

[0101] In step S500, the cooling system is an important part to ensure the stable operation of the magnetic levitation air separation expansion machine system. The cooling system includes a gas shunt pipeline and a liquid nitrogen injection device. The gas shunt pipeline and the liquid nitrogen injection device are respectively connected to the expansion end volute and the braking end volute. The function of the gas shunt pipeline is to shunt the high-temperature gas so that it flows in different paths, thereby increasing the contact area and time between the gas and the cooling medium and improving the cooling efficiency. The liquid nitrogen injection device uses the low-temperature characteristics of liquid nitrogen to quickly cool the high-temperature gas. The liquid nitrogen injection volume is controlled in a gradient of 0.1 - 0.3 L / s, and the system will adjust the liquid nitrogen injection volume in real time according to parameters such as the temperature, pressure, and flow rate of the gas. This gradient control method can optimize the use of liquid nitrogen while ensuring the cooling effect, avoiding unnecessary energy waste. By effectively cooling the high-temperature gas through the cooling system, it can ensure that the gas is at an appropriate working temperature during the subsequent expansion process, improving the operating efficiency and stability of the entire system.

[0102] Furthermore, in step S600, the PID closed-loop control algorithm further includes the following steps: S610. When the pressure fluctuation of the fractionating tower 205 exceeds ±5%, adaptively adjust the proportional coefficient to 1.2 - 1.8. When the pressure fluctuation of the fractionating tower exceeds ±5%, the system automatically adjusts the proportional coefficient to 1.2 - 1.8. The appropriate increase in the proportional coefficient enables the system to respond more quickly to pressure changes. By quickly adjusting the electromagnetic force, the position of the rotor assembly can be corrected in a timely manner, reducing the impact of pressure fluctuations on the rotor suspension stability and ensuring that the system can still operate stably under changing working conditions.

[0103] S620. When the rotor vibration frequency exceeds 150 Hz, the integral time constant is preferentially reduced to 0.2 seconds. Reducing the integral time constant: If the rotor vibration frequency exceeds 150 Hz, the system will preferentially reduce the integral time constant to 0.2 seconds. Shortening the integral time constant can accelerate the system's response speed to vibration, enabling the integral action to more promptly eliminate the accumulation of rotor position deviation, suppressing the continuous development of vibration, quickly restoring the stable suspension state of the rotor, and ensuring the reliable operation of the equipment.

[0104] S630. When the cooling efficiency of the liquid nitrogen injection device decreases, the fuzzy control mode is triggered to compensate for the electromagnetic force deviation. Triggering the fuzzy control mode: Once the cooling efficiency of the liquid nitrogen injection device decreases, the system immediately triggers the fuzzy control mode. The fuzzy control mode can, according to the fuzzy rules of the system, flexibly and accurately compensate for the electromagnetic force deviation when the cooling efficiency is insufficient. By comprehensively considering various relevant factors, it automatically adjusts the electromagnetic force to ensure that the rotor assembly always maintains a stable suspension state and maintains the normal operation of the system.

[0105] In step S600, the controller adjusts the liquid nitrogen injection amount in real time according to the feedback data of the temperature sensor and synchronizes it with the pressure change of the fractionating tower 205 to ensure the stability of the rectification process.

[0106] The controller accurately adjusts the liquid nitrogen injection amount based on the real-time feedback data of the temperature sensor. At the same time, the controller synchronizes and coordinates the adjustment of the liquid nitrogen injection amount with the pressure change of the fractionating tower. When the pressure of the fractionating tower changes, it promptly adjusts the liquid nitrogen injection amount to make the cooling effect adapt to the system working conditions and ensure the stable progress of the rectification process.

[0107] The working principle of the present invention is as follows: Magnetic levitation support principle: The magnetic levitation bearing assembly makes the rotor assembly levitate without contact through electromagnetic force, ensuring that the rotor assembly avoids contact with the fuselage during operation and guaranteeing the safety and stability of the equipment.

[0108] Gas expansion and pressurization principle: The air compressor compresses air and sends it into the system. After being pressurized by the braking impeller and cooled by the cooler, the gas enters the expansion end volute. By adjusting the flow rate and velocity through the nozzle adjustable mechanism, it drives the expansion impeller to rotate, realizing the gas expansion and refrigeration process.

[0109] Axial force balance principle: During the gas expansion and pressurization process, through the cooperation of the thrust disc and the axial thrust magnetic levitation bearing, the axial force of the rotor assembly is balanced to ensure the axial stability of the rotor assembly.

[0110] Sealing and heat insulation principle: The shaft seal device forms a gas film seal by injecting nitrogen or air to prevent gas leakage and impurity entry. The heat insulation structure blocks the heat conduction between the expansion end and the braking end, ensuring their respective working temperature environments, improving the thermal efficiency and operation stability of the equipment.

[0111] Principle of the cooling system: The cooling system includes a gas diversion pipeline and a liquid nitrogen injection device. The gas is guided to different cooling paths through the diversion pipeline, and the high-temperature gas is rapidly cooled by injecting liquid nitrogen to ensure the safe operation and thermal efficiency of the equipment.

[0112] In summary, the beneficial effects of the present invention are as follows: High efficiency and energy saving: The magnetic levitation bearing assembly realizes non-contact suspension of the rotor, eliminates mechanical friction, reduces energy loss, and significantly improves the operating efficiency and energy saving effect compared with the traditional oil film bearing system, effectively reducing the energy consumption during the air separation process.

[0113] Stable and reliable: The magnetic levitation bearing and the control module work together to accurately adjust the electromagnetic force through the PID closed-loop control algorithm to ensure the stable suspension of the rotor, avoid vibration and mechanical wear, greatly improve the operating stability and reliability of the equipment, reduce the risk of failure, and ensure the continuity of air separation production.

[0114] Long service life and low maintenance: The magnetic levitation design without mechanical contact significantly reduces component wear, extends the service life of the equipment, simplifies the maintenance process, reduces the maintenance cost and downtime, and improves the equipment utilization rate and economic benefits.

[0115] Precise control and strong adaptability: The nozzle adjustable mechanism automatically adjusts the gas flow rate and expansion efficiency according to the pressure of the fractionating tower. Combined with the intelligent control algorithm, the system can maintain optimal operation under different working conditions, has excellent load adaptability and working condition adjustment ability, and meets diverse production requirements.

Claims

1. A magnetic levitation air separation expander system, characterized in that, Comprising: A base (106); A magnetic levitation bearing assembly disposed on the base (106), including a radial magnetic levitation bearing at the expansion end (4), a radial magnetic levitation bearing at the braking end (7), and an axial thrust magnetic levitation bearing (5). The radial magnetic levitation bearing at the expansion end (4) and the axial thrust magnetic levitation bearing (5) are fixed on the fuselage (111), corresponding to the expansion end AMB rotor assembly (10) and the thrust disk on the rotor assembly respectively, for supporting the radial and axial forces of the rotor assembly at the expansion end; the radial magnetic levitation bearing at the braking end (7) is fixed on the fuselage (111), corresponding to the braking end AMB rotor assembly (9) on the rotor assembly, for supporting the radial force of the rotor assembly at the braking end; A rotor assembly disposed inside the fuselage (111), connected to the fuselage (111) through the magnetic levitation bearing assembly to achieve contactless suspension; A control module electrically connected to the magnetic levitation bearing assembly, for controlling the magnetic levitation bearing assembly to suspend the rotor.

2. The magnetic levitation air separation expander system according to claim 1, wherein The rotor assembly includes a main shaft (6), with an expansion impeller (1) and a braking impeller (8) connected to both ends thereof respectively; The braking end AMB rotor assembly (9) and the expansion end AMB rotor assembly (10); symmetrically disposed at both ends of the main shaft (6) and corresponding to the magnetic levitation bearing assembly; The thrust disk is integrally formed with the main shaft (6), located at the middle position of the main shaft (6), and cooperates with the axial thrust magnetic levitation bearing (5) for balancing the axial force of the rotor assembly.

3. The magnetic levitation air separation expansion machine system according to claim 2, wherein Further comprising: A shaft seal device (2) which is provided with a sealed gas channel surrounding the main shaft (6), and forms a gas film seal by injecting nitrogen or air.

4. The magnetic levitation air separation expansion machine system according to claim 3, characterized in that, Further comprising a heat insulation structure, which is disposed between the expansion end and the braking end, connected to the fuselage (111) and the base (106); for blocking the heat conduction between the expansion end and the braking end.

5. The magnetic levitation air separation expansion machine system according to claim 4, wherein, The rotor assembly further includes auxiliary bearings (3), disposed at both ends of the main shaft (6) and arranged side by side with the magnetic levitation bearing assembly, for providing mechanical support when magnetic levitation fails or power is cut off.

6. The magnetic levitation air separation expansion machine system according to claim 5, characterized in that, Both the expansion impeller (1) and the braking impeller (8) adopt a closed three-dimensional impeller structure, and the expansion end volute (101) and the braking end volute are physically isolated by the heat insulation structure. The expansion end volute (101) is connected to a nozzle adjustable mechanism (103) for adjusting the gas flow rate and expansion efficiency according to the real-time gas pressure of the fractionating tower (205).

7. The magnetic levitation air separation expansion machine system according to claim 6, characterized in that The control module further includes a cooling system, which includes a gas diversion pipeline and a liquid nitrogen injection device, respectively connected to the expansion end volute (101) and the braking end volute, for diverting and cooling the expanded low-temperature gas and the pressurized high-temperature gas.

8. A method for operating a magnetic levitation air separation expansion machine system according to any one of claims 1-7, characterized in that Including the following steps: S100. Before startup, perform self-check on the magnetic levitation bearing assembly through the controller to confirm that the sensors and power amplifiers are in normal state; S200. Energize the iron core coil, monitor the rotor suspension position through the displacement sensor, and adjust the current to make the rotor suspend at the set equilibrium point; S300. Start the air compressor (202). After purifying the compressed air through the molecular sieve (204), input it into the brake impeller (8) for pressurization through the bellows at the pressurization end inlet (117). S400. After the pressurized gas is cooled by the cooler (206), it enters the volute at the expansion end (101). Adjust the flow rate through the nozzle adjustment mechanism (103) to drive the expansion impeller (1) to output mechanical work externally. S500. The expanded low-temperature gas enters the fractionating tower (205) for rectification. At the same time, the high-temperature pressurized gas is shunted and cooled through the cooling system. S600. Collect the rotor vibration, temperature, and position data in real time. Dynamically adjust the electromagnetic force through the PID closed-loop control algorithm to maintain the stable suspension of the rotor.

9. The operating method of the magnetic levitation air separation expansion machine system according to claim 8, characterized in that, In step S100, the self-check process of the magnetic suspension bearing includes: Perform sensor zero calibration and power amplifier gain test; Generate a self-check report and mark the abnormal channels; Conduct no-load current tests on the axial / radial electromagnets to verify the insulation performance of the coils; If it is detected that the displacement sensor fails, automatically switch to the eddy current probe standby measurement mode; In step S500, the cooling system includes a gas shunt pipeline and a liquid nitrogen injection device, which are respectively connected to the volute at the expansion end (101) and the volute at the brake end. The liquid nitrogen injection volume is controlled in a gradient of 0.1 - 0.3 L / s.

10. The operating method of the magnetic levitation air separation expansion machine system according to claim 8, characterized in that In step S600, the PID closed-loop control algorithm further includes the following steps: S610. When the pressure fluctuation of the fractionating tower (205) exceeds ±5%, adaptively adjust the proportional coefficient to 1.2 - 1.8; S620. When the rotor vibration frequency exceeds 150 Hz, preferentially reduce the integral time constant to 0.2 seconds; S630. When the cooling efficiency of the liquid nitrogen injection device decreases, trigger the fuzzy control mode to compensate for the electromagnetic force deviation; In step S600, the controller adjusts the liquid nitrogen injection volume in real time according to the feedback data of the temperature sensor, and synchronizes with the pressure change of the fractionating tower (205) to ensure the stability of the rectification process.

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