Zero-leakage magnetic suspension motor direct-driven supercritical carbon dioxide compressor

Abstract

The invention relates to the technical field of compressors, in particular to a zero-leakage magnetic suspension motor direct-driven supercritical carbon dioxide compressor which comprises a motor shell, a first-stage compressor shell, a first-stage impeller, a second-stage compressor shell, a second-stage impeller, a stator, a main shaft, a sealing assembly and a cooling assembly. The stator is arranged in the motor shell, the main shaft is driven by electromagnetic torque generated by the stator to rotate, the first-stage compressor shell and the second-stage compressor shell are installed at the two ends of the motor shell in a suspended mode, the first-stage impeller and the second-stage impeller are arranged at the two ends of the main shaft respectively, and a first magnetic suspension radial bearing is arranged on the side, close to the first-stage impeller, of the stator. And a first protection bearing is arranged on the side, away from the stator, of the first magnetic suspension radial bearing. In this way, the technical problems that in the prior art, a supercritical carbon dioxide compressor uses multiple dry gas sealing accessory devices, the size is large, the operation difficulty is large, and zero leakage cannot be achieved are solved.

Description

Technical Field

[0001] The present invention relates to the technical field of compressors, and in particular to a zero-leakage magnetic levitation motor directly driven supercritical carbon dioxide compressor. Background Art

[0002] At present, small and medium power supercritical carbon dioxide impeller compressors (usually refers to power less than 1 , speed less than 20000 ) typically utilizes a high-speed oil-bearing direct-drive motor, with the compressor impeller directly connected to the motor shaft, and the compressor casing suspended from the motor housing. Due to the high internal pressures (8-20 MPa) within supercritical CO2 compressors, dry gas seals are often used as shaft end seals to minimize leakage of the high-pressure refrigerant within the compressor. However, dry gas seals require a complex control system, including a booster compressor unit (to provide the high-pressure seal gas source), an electric heater unit (to increase the seal gas temperature), a filter unit (to enhance seal gas cleanliness), a regulating valve and flowmeter (to regulate the seal gas flow), and piping. This control system constitutes a bulky control station, occupying a large footprint. The dry gas seal body installed in the compressor is a precision component, requiring strict control of parameters such as starting pressure, starting speed, and seal gas flow. During installation, if seal gas is not added, jogging the motor to check the rotation direction risks accelerated wear of the dry gas seal body. Due to the nature of dry gas seals, zero external leakage is not possible, increasing the risk of asphyxiation and the difficulty of refrigerant filling in certain confined environments where the compressor is used.

[0003] In summary, the supercritical carbon dioxide compressor in the prior art has the problems of using many dry gas sealing accessories, being bulky, difficult to operate, and being unable to achieve zero leakage. Summary of the Invention

[0004] The purpose of the present invention is to provide a zero-leakage magnetic levitation motor directly driven supercritical carbon dioxide compressor, aiming to solve the technical problems of the supercritical carbon dioxide compressor in the prior art, such as the use of many dry gas sealing accessories, large size, high difficulty in operation, and inability to achieve zero leakage.

[0005] To achieve the above-mentioned object, the present invention adopts a zero-leakage magnetic levitation motor directly driven supercritical carbon dioxide compressor, comprising a motor housing, a first-stage compressor housing, a first-stage impeller, a second-stage compressor housing, a second-stage impeller, a stator, a main shaft, a sealing assembly and a cooling assembly; The stator is arranged in the motor housing, and the main shaft is driven to rotate by the electromagnetic torque generated by the stator. The first-stage compressor housing and the second-stage compressor housing are suspended and installed at both ends of the motor housing. The first-stage impeller and the second-stage impeller are respectively arranged at both ends of the main shaft. A first magnetic levitation radial bearing is provided on the side of the stator close to the first-stage impeller, and a first protective bearing is provided on the side of the first magnetic levitation radial bearing away from the stator. Two magnetic levitation thrust bearings, a second magnetic levitation radial bearing and a second protective bearing are sequentially provided on the side of the stator close to the second-stage impeller. The sealing assembly is arranged in the motor housing; the cooling assemblies are both connected to the first-stage compressor housing and the second-stage compressor housing, and a compressor interstage pipeline is provided between the first-stage compressor housing and the second-stage compressor housing.

[0006] In which, the cooling assembly includes a cooling air pipeline, a water cooler, a temperature sensor, a cooling water regulating valve, a first cooling air regulating valve, a second cooling air regulating valve, a first flow meter, a second flow meter and a recovery pipeline. The cooling air pipeline is connected to the outlet pipeline of the secondary compressor housing, the first cooling air regulating valve and the second cooling air regulating valve are both connected to the cooling air pipeline, the water cooler and the temperature sensor are both arranged on the cooling air pipeline, the cooling water regulating valve is connected to the water cooler and the temperature sensor, the first flow meter and the second flow meter are respectively connected to the first cooling air regulating valve and the second cooling air regulating valve, the first flow meter and the second flow meter are both connected to the motor housing, and the recovery pipeline is connected to the motor housing and the inlet of the first-stage compressor housing.

[0007] The sealing assembly includes a first sealing unit and a second sealing unit, and the first sealing unit and the second sealing unit are both arranged in the motor housing.

[0008] The first sealing unit includes a first carbon ring seal and a first labyrinth seal, and both the first carbon ring seal and the first labyrinth seal are arranged between the first-stage impeller and the first protective bearing.

[0009] The second sealing unit includes two second carbon ring seals and a second labyrinth seal, and the two second carbon ring seals and the second labyrinth seal are both arranged between the secondary impeller and the second protective bearing.

[0010] The zero-leakage magnetic levitation motor directly driven supercritical carbon dioxide compressor further includes a balance air pipe, one end of which is placed between the two second carbon ring seals, and the other end of which is connected to the first-stage compressor housing.

[0011] The present invention discloses a zero-leakage magnetic levitation motor directly driven supercritical carbon dioxide compressor. In specific use, the present invention balances thrust, and the compressor adopts two-stage compression. The first-stage impeller and the second-stage impeller are directly connected to both ends of the main shaft. The first-stage compressor housing and the second-stage compressor housing are suspended at both ends of the motor housing. The stator is installed inside the motor housing for generating electromagnetic torque, thereby driving the main shaft to rotate. Two magnetic levitation thrust bearings, a second magnetic levitation radial bearing, and a second protective bearing are sequentially provided on the side of the stator close to the second-stage impeller. The sealing assembly is provided in the motor housing and is respectively used to support the suspension of the main shaft during operation, withstand bidirectional thrust, and support the rotation of the main shaft in the event of magnetic levitation bearing failure in unexpected working conditions. The sealing assembly can reduce the leakage of high-pressure gas from the back of the first-stage impeller and the second-stage impeller into the interior of the motor housing. The cooling assembly is used to cool the interior of the motor. In this way, the technical problems of supercritical carbon dioxide compressors in the prior art, such as the use of multiple dry gas sealing accessories, large size, high operation difficulty, and inability to achieve zero leakage, are solved. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0013] Figure 1 It is a structural schematic diagram of a zero-leakage magnetic levitation motor directly driving a supercritical carbon dioxide compressor according to the present invention.

[0014] 1-motor housing, 2-first-stage compressor housing, 3-first-stage impeller, 4-second-stage compressor housing, 5-second-stage impeller, 6-stator, 7-main shaft, 8-cooling air pipeline, 9-water cooler, 10-temperature sensor, 11-cooling water regulating valve, 12-first cooling air regulating valve, 13-second cooling air regulating valve, 14-first flow meter, 15-second flow meter, 16-recovery pipeline, 17-first carbon ring seal, 18-first labyrinth seal, 19-second carbon ring seal, 20-second labyrinth seal, 21-balance air pipe, 22-first magnetic levitation radial bearing, 23-first protection bearing, 24-magnetic levitation thrust bearing, 25-second magnetic levitation radial bearing, 26-second protection bearing, 27-compressor interstage pipeline, 28-first-stage compressor inlet pipeline, 29-outlet pipeline, 30-motor stator temperature sensor. DETAILED DESCRIPTION

[0015] The embodiments of the present invention are described in detail below. Examples of the embodiments are shown in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, but should not be understood as limiting the present invention.

[0016] See also Figure 1 , Figure 1 It is a structural schematic diagram of a zero-leakage magnetic levitation motor directly driving a supercritical carbon dioxide compressor according to the present invention.

[0017] The present invention provides a zero-leakage magnetic levitation motor directly driven supercritical carbon dioxide compressor, comprising a motor housing 1, a first-stage compressor housing 2, a first-stage impeller 3, a second-stage compressor housing 4, a second-stage impeller 5, a stator 6, a main shaft 7, a sealing assembly and a cooling assembly; The stator 6 is arranged in the motor housing 1, and the main shaft 7 is driven to rotate by the electromagnetic torque generated by the stator 6. The first-stage compressor housing 2 and the second-stage compressor housing 4 are suspended and installed at both ends of the motor housing 1. The first-stage impeller 3 and the second-stage impeller 5 are respectively arranged at both ends of the main shaft 7. A first magnetic levitation radial bearing 22 is provided on the side of the stator 6 close to the first-stage impeller 3, and a first protective bearing 23 is provided on the side of the first magnetic levitation radial bearing 22 away from the stator 6. Two magnetic levitation thrust bearings 24, a second magnetic levitation radial bearing 25 and a second protective bearing 26 are sequentially provided on the side of the stator 6 close to the second-stage impeller 5. The sealing assembly is arranged in the motor housing 1; the cooling assemblies are all connected to the first-stage compressor housing 2 and the second-stage compressor housing 4, and a compressor interstage pipeline 27 is provided between the first-stage compressor housing 2 and the second-stage compressor housing 4; The zero-leakage magnetic levitation motor directly driven supercritical carbon dioxide compressor further includes a motor stator temperature sensor 30, which is connected to the stator 6. With respect to this specific embodiment, in specific use, the present invention balances thrust, and the compressor adopts two-stage compression. The first-stage impeller 3 and the second-stage impeller 5 are directly connected to both ends of the main shaft 7. The first-stage compressor housing 2 and the second-stage compressor housing 4 are suspended and mounted at both ends of the motor housing 1. The stator 6 is installed inside the motor housing 1 for generating electromagnetic torque, thereby driving the main shaft 7 to rotate. Two magnetic levitation thrust bearings 24, a second magnetic levitation radial bearing 25, and a second protective bearing 26 are sequentially provided on the side of the stator 6 close to the second-stage impeller 5. The sealing assembly is provided in the motor housing 1, and is respectively used to support the suspension of the main shaft 7 during operation, withstand bidirectional thrust, and support the rotation of the main shaft 7 in the event of magnetic bearing failure in unexpected working conditions. The sealing assembly can reduce the leakage of high-pressure gas from the back of the first-stage impeller 3 and the second-stage impeller 5 into the interior of the motor housing 1. The cooling assembly is used to cool the interior of the motor. In this way, the technical problems of the supercritical carbon dioxide compressor in the prior art, such as the use of many dry gas sealing accessories, large size, high operation difficulty, and inability to achieve zero leakage, are solved.

[0018] Among them, the cooling component includes a cooling air pipeline 8, a water cooler 9, a temperature sensor 10, a cooling water regulating valve 11, a first cooling air regulating valve 12, a second cooling air regulating valve 13, a first flow meter 14, a second flow meter 15 and a recovery pipeline 16. The cooling air pipeline 8 is connected to the outlet pipeline 29 of the secondary compressor housing 4, the first cooling air regulating valve 12 and the second cooling air regulating valve 13 are both connected to the cooling air pipeline 8, the water cooler 9 and the temperature sensor 10 are both arranged on the cooling air pipeline 8, the cooling water regulating valve 11 is connected to the water cooler 9 and the temperature sensor 10, the first flow meter 14 and the second flow meter 15 are respectively connected to the first cooling air regulating valve 12 and the second cooling air regulating valve 13, the first flow meter 14 and the second flow meter 15 are both connected to the motor housing 1, and the recovery pipeline 16 is connected to the motor housing 1 and the inlet of the first-stage compressor housing 2.

[0019] For this specific embodiment, the cooling air pipeline 8 is connected to the water cooler 9 and the temperature sensor 10, and the cooling air temperature is adjusted by the cooling water regulating valve 11. The cooling pipeline is divided into two routes to enter the two-stage compressor, and the cooling flow is adjusted by the first cooler regulating valve and the second cooling air. The cooling flow is measured by the first flowmeter 14 and the second flowmeter 15. The cooling air on the side of the first compressor casing 2 passes through the first labyrinth seal 18, the first protective bearing 23, the first magnetic levitation radial bearing 22, the stator 6, the two second magnetic levitation thrust bearings 24, the second magnetic levitation radial bearing 25, and the second protective bearing 26 in sequence. The cooling air on the side of the secondary compressor casing 4 passes through the second labyrinth seal 20. After the cooling air on both sides merges, it flows into the inlet pipeline of the first compressor casing 2 through the recovery pipeline 16 to complete the cooling of the inside of the motor.

[0020] Secondly, the sealing assembly includes a first sealing unit and a second sealing unit, and the first sealing unit and the second sealing unit are both arranged in the motor housing 1.

[0021] According to this specific embodiment, the first sealing unit and the second sealing unit cooperate to reduce the leakage of the high-pressure gas on the back of the first-stage impeller 3 and the second-stage impeller 5 to the inside of the motor housing 1.

[0022] Meanwhile, the first sealing unit includes a first carbon ring seal 17 and a first labyrinth seal 18 . Both the first carbon ring seal 17 and the first labyrinth seal 18 are disposed between the first-stage impeller 3 and the first protective bearing 23 .

[0023] The second sealing unit includes two second carbon ring seals 19 and a second labyrinth seal 20 . Both the two second carbon ring seals 19 and the second labyrinth seal 20 are disposed between the secondary impeller 5 and the second protective bearing 26 .

[0024] According to this specific embodiment, the first carbon ring seal 17 and the first labyrinth seal 18 are installed between the first-stage impeller 3 and the first protective bearing 23, and the second carbon ring seal 19 and the second labyrinth seal 20 are installed between the second-stage impeller 5 and the second protective bearing 26, so as to reduce the leakage of the high-pressure gas on the back of the first-stage impeller 3 and the second-stage impeller 5 to the inside of the motor housing 1.

[0025] Again, the zero-leakage magnetic levitation motor directly driven supercritical carbon dioxide compressor further includes a balance air pipe 21 , one end of the balance air pipe 21 is placed between the two second carbon ring seals 19 , and the other end of the balance air pipe 21 is connected to the first-stage compressor housing 2 .

[0026] According to this specific embodiment, the balancing air pipe 21 is provided to reduce the back pressure of the secondary impeller 5 .

[0027] A zero-leakage magnetic levitation motor directly drives a supercritical carbon dioxide compressor using this embodiment. In specific use, the present invention balances thrust, and the compressor adopts two-stage compression. The first-stage impeller 3 and the second-stage impeller 5 are directly connected to the two ends of the main shaft 7, and the first-stage compressor housing 2 and the second-stage compressor housing 4 are suspended and installed at both ends of the motor housing 1. The stator 6 is installed inside the motor housing 1 to generate electromagnetic torque, thereby driving the main shaft 7 to rotate. The stator 6 is close to the side of the second-stage impeller 5 and is sequentially provided with two magnetic levitation thrust bearings 24, a second magnetic levitation radial bearing 25 and The second protective bearing 26, the sealing component is arranged in the motor housing 1, and is respectively used to support the suspension of the main shaft 7 during operation, to withstand bidirectional thrust, and to support the rotation of the main shaft 7 when the magnetic bearing fails in an unexpected working condition. Through the provided sealing component, the leakage of the high-pressure gas on the back of the first-stage impeller 3 and the second-stage impeller 5 to the inside of the motor housing 1 can be reduced. The cooling component is used for cooling the inside of the motor, thereby solving the technical problems of the supercritical carbon dioxide compressor in the prior art, such as the use of many dry gas sealing accessories, large size, high difficulty in operation, and inability to achieve zero leakage.

[0028] The above disclosure is only a preferred embodiment of the present invention, and certainly cannot be used to limit the scope of the rights of the present invention. Ordinary technicians in this field can understand that all or part of the processes of the above embodiment and equivalent changes made in accordance with the claims of the present invention are still within the scope of the invention.

Claims

1. A zero-leakage magnetic levitation motor directly drives a supercritical carbon dioxide compressor, characterized in that: It includes a motor housing, a first-stage compressor housing, a first-stage impeller, a second-stage compressor housing, a second-stage impeller, a stator, a main shaft, a sealing assembly and a cooling assembly; The stator is arranged in the motor housing, and the main shaft is driven to rotate by the electromagnetic torque generated by the stator. The first-stage compressor housing and the second-stage compressor housing are suspended and installed at both ends of the motor housing. The first-stage impeller and the second-stage impeller are respectively arranged at both ends of the main shaft. A first magnetic levitation radial bearing is provided on the side of the stator close to the first-stage impeller, and a first protective bearing is provided on the side of the first magnetic levitation radial bearing away from the stator. Two magnetic levitation thrust bearings, a second magnetic levitation radial bearing and a second protective bearing are sequentially provided on the side of the stator close to the second-stage impeller. The sealing assembly is arranged in the motor housing; the cooling assemblies are both connected to the first-stage compressor housing and the second-stage compressor housing, and a compressor interstage pipeline is provided between the first-stage compressor housing and the second-stage compressor housing.

2. The zero-leakage magnetic levitation motor directly driven supercritical carbon dioxide compressor according to claim 1, characterized in that: The cooling assembly includes a cooling air pipeline, a water cooler, a temperature sensor, a cooling water regulating valve, a first cooling air regulating valve, a second cooling air regulating valve, a first flow meter, a second flow meter and a recovery pipeline. The cooling air pipeline is connected to the outlet pipeline of the secondary compressor housing, the first cooling air regulating valve and the second cooling air regulating valve are both connected to the cooling air pipeline, the water cooler and the temperature sensor are both arranged on the cooling air pipeline, the cooling water regulating valve is connected to the water cooler and the temperature sensor, the first flow meter and the second flow meter are respectively connected to the first cooling air regulating valve and the second cooling air regulating valve, the first flow meter and the second flow meter are both connected to the motor housing, and the recovery pipeline is connected to the motor housing and the inlet of the first-stage compressor housing.

3. The zero-leakage magnetic levitation motor directly driven supercritical carbon dioxide compressor according to claim 2, characterized in that: The sealing assembly includes a first sealing unit and a second sealing unit, and the first sealing unit and the second sealing unit are both disposed in the motor housing.

4. The zero-leakage magnetic levitation motor directly driven supercritical carbon dioxide compressor according to claim 3, characterized in that: The first sealing unit includes a first carbon ring seal and a first labyrinth seal, and both the first carbon ring seal and the first labyrinth seal are arranged between the first-stage impeller and the first protection bearing.

5. The zero-leakage magnetic levitation motor directly driven supercritical carbon dioxide compressor according to claim 4, characterized in that: The second sealing unit includes two second carbon ring seals and a second labyrinth seal. The two second carbon ring seals and the second labyrinth seal are both arranged between the secondary impeller and the second protective bearing.

6. The zero-leakage magnetic levitation motor directly driven supercritical carbon dioxide compressor according to claim 5, characterized in that: The zero-leakage magnetic levitation motor directly driven supercritical carbon dioxide compressor further includes a balance air pipe, one end of which is placed between the two second carbon ring seals, and the other end of which is connected to the first-stage compressor housing.

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