High-capacity single-shaft multi-stage supercritical CO2 centrifugal compressor

Abstract

The utility model discloses a high-capacity single-shaft multi-stage supercritical CO2 centrifugal compressor. Design and manufacturing of the compressor and the turbine are key links for realizing circulation of the whole system. However, measurement data of important physical parameters such as working medium viscosity, specific thermal conductivity and thermal coefficient of CO2 near a near-critical point are not perfect. The centrifugal pump comprises a main shaft, a cylinder body and an end cover, the end cover is fixed to the cylinder body through a fastening bolt, the main shaft is provided with multiple stages of impellers and multiple stages of spacer bushes through shrinkage fit, every two adjacent stages of impellers are separated through the corresponding spacer bush, and the main shaft is provided with a balance drum through shrinkage fit and pressed through a locking nut; an air inlet partition plate, an air outlet partition plate and a multi-stage partition plate are installed in the cylinder body, and the multi-stage partition plate is located between every two adjacent stages of impellers. The air outlet partition plate is fastened to the outlet side end cover through a bolt, and a variable cross-section flow channel is arranged between the last-stage partition plate and the air outlet partition plate. The multi-stage supercritical CO2 centrifugal compressor is applied to the multi-stage supercritical CO2 centrifugal compressor.

Description

Technical Field

[0001] The utility model relates to a large-capacity single-shaft multi-stage supercritical CO2 centrifugal compressor. Background Art

[0002] For coal-fired power generation systems, the supercritical carbon dioxide Brayton cycle has the advantages of high power generation efficiency and small system size compared to the traditional steam Rankine cycle. It is considered to be one of the most promising solutions in the future clean energy power generation field and is very suitable as a power system for clean energy such as solar thermal power generation and high-temperature nuclear power.

[0003] The design and manufacture of compressors and turbines are crucial for achieving the entire system cycle. However, due to the incompleteness of measurement data for key physical properties of CO2 near its critical point, such as viscosity, specific thermal conductivity, and thermal coefficient, the design and performance testing of compressors using CO2 as a working fluid are still in the exploratory and developmental stages, both domestically and internationally. Utility Model Content

[0004] The purpose of the utility model is to solve the above-mentioned problems, thereby providing a large-capacity single-shaft multi-stage supercritical CO2 centrifugal compressor.

[0005] The above purpose is achieved through the following technical solutions:

[0006] A large-capacity single-shaft multi-stage supercritical CO2 centrifugal compressor, comprising: a main shaft, a cylinder body, and an end cover, wherein the end cover is fixed to the cylinder body by tightening bolts, the main shaft is mounted with a red sleeve to install multi-stage impellers and multi-stage spacers, and adjacent impellers are separated by spacers, and a balance drum is mounted on the main shaft by a red sleeve and tightened by a lock nut;

[0007] An air inlet baffle, an air outlet baffle and a multi-stage baffle are installed in the cylinder body, and the multi-stage baffle is located between the impellers of two adjacent stages;

[0008] The air outlet baffle is fastened to the outlet side end cover by bolts, and a variable cross-section flow channel is arranged between the baffle of the last stage and the air outlet baffle.

[0009] The large-capacity single-shaft multi-stage supercritical CO2 centrifugal compressor has an air inlet and an air outlet installed on the cylinder body. The air inlet is located at the air inlet baffle, and the air outlet is located at the air outlet baffle.

[0010] In the large-capacity single-shaft multi-stage supercritical CO2 centrifugal compressor, a thrust plate is installed at one end of the main shaft. The thrust plate and the main shaft are matched with each other in a taper and are locked by a nut.

[0011] In the large-capacity single-shaft multi-stage supercritical CO2 centrifugal compressor, the air inlet partition and the multi-stage partitions are respectively inlaid with mouth ring seals, and the mouth ring seals have multiple small air sealing teeth.

[0012] In the large-capacity single-shaft multi-stage supercritical CO2 centrifugal compressor, a balance drum seal is embedded on the gas outlet baffle, and the balance drum seal has multiple atmospheric sealing teeth. Beneficial effects

[0013] 1. The air intake baffle and the 1-3 level baffles of this utility model are tightened by tie rod bolts, and a sealing ring is provided between the mating surfaces of the baffle stoppers to ensure that there is no internal leakage between the baffles.

[0014] 2. The air outlet baffle of the utility model is fastened to the outlet side end cover by bolts, and a variable cross-section flow channel is set between the third-stage baffle and the air outlet baffle. The cross-section of the variable cross-section flow channel gradually increases near the air outlet to prevent the occurrence of surge. In a centrifugal compressor, when the flow rate is reduced to a certain level, the air flow in the flow channel will experience boundary layer separation, causing the compressor outlet pressure to suddenly drop below the pressure in the pipe network, thereby causing the air flow to flow back. This periodic air flow oscillation phenomenon is called surge. In order to prevent surge, a gradual flow channel is usually set at the compressor outlet to gradually expand the air flow and reduce the possibility of boundary layer separation, thereby stabilizing the air flow and preventing the occurrence of surge. In addition, the design of the gradual flow channel can also optimize the flow state of the air flow, reduce flow losses, and improve the efficiency of the compressor. Finally, the air is discharged from the compressor through the air outlet to complete the entire compression process.

[0015] 3. The interstage seal of this utility model adopts a labyrinth seal with gas sealing pieces, and the gas seals at both ends adopt dry gas seals, which can ensure the reliability of the seal under high pressure difference and prevent CO2 leakage. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a structural diagram of the utility model;

[0017] Figure 2 It is a structural diagram of the main shaft;

[0018] Figure 3 yes Figure 1 A magnified view of part A;

[0019] Figure 4 yes Figure 1 A magnified view of part B;

[0020] In the figure: 1. thrust plate; 2. main shaft; 3. spacer; 4. first-stage impeller; 5. second-stage impeller; 6. third-stage impeller; 7. fourth-stage impeller; 8. balance drum; 9. locking nut; 10. thrust bearing; 12. air inlet pipe; 13. air inlet baffle; 14. first-stage baffle; 15. cylinder body; 16. second-stage baffle; 17. third-stage baffle; 18. air outlet pipe; 19. air outlet baffle; 20. end cover; 22. sealing ring; 23. mouth ring seal; 24. small air seal tooth; 25. balance drum seal; 26. large air seal tooth; 27. variable-section flow channel. DETAILED DESCRIPTION

[0021] Reference Figure 1-Figure 4 A large-capacity single-shaft multi-stage supercritical CO2 centrifugal compressor, comprising: a main shaft 2, a cylinder body 15 and an end cover 20. The end cover is fixed to the cylinder body by tightening bolts. The main shaft is equipped with a red sleeve to install multi-stage impellers and multi-stage spacer sleeves 3. As shown in the figure, there are four impellers, a first-stage impeller 4, a second-stage impeller 5, a third-stage impeller 6 and a fourth-stage impeller 7. The impellers of adjacent stages are separated by spacer sleeves 3. A balance drum 8 is installed on the main shaft using a red sleeve and is tightened by a lock nut 9.

[0022] The cylinder body is equipped with an air inlet baffle 13, an air outlet baffle 19 and a multi-stage baffle. There are three levels of baffles, namely, the first-stage baffle 14, the second-stage baffle 16 and the third-stage baffle 17. The multi-stage baffles are located between the impellers of two adjacent stages.

[0023] The air outlet baffle is fastened to the outlet side end cover 20 by bolts, and a variable cross-section flow channel 27 is provided between the baffle of the last stage and the air outlet baffle, and a variable cross-section flow channel is provided between the baffle of the third stage and the air outlet baffle. The cross-section of the variable cross-section flow channel gradually increases near the air outlet duct to prevent the occurrence of surge. In a centrifugal compressor, when the flow rate is reduced to a certain extent, the air flow in the flow channel will experience boundary layer separation, causing the compressor outlet pressure to suddenly drop below the pressure in the pipe network, thereby causing the air flow to flow back. This periodic air flow oscillation phenomenon is called surge. In order to prevent surge, a gradual flow channel is usually provided at the compressor outlet to gradually expand the air flow and reduce the possibility of boundary layer separation, thereby stabilizing the air flow and preventing the occurrence of surge. In addition, the design of the gradual flow channel can also optimize the flow state of the air flow, reduce flow loss, and improve the efficiency of the compressor. The air is finally discharged from the compressor through the air outlet duct to complete the entire compression process.

[0024] An air inlet 12 and an air outlet 18 are mounted on the cylinder body. The air inlet is located at the air inlet baffle, and the air outlet is located at the air outlet baffle.

[0025] A thrust plate 1 is installed at one end of the main shaft. The thrust plate and the main shaft 2 are matched with each other in a taper and are locked by a nut.

[0026] The air intake baffle and the multi-stage baffles are respectively inlaid with a mouth ring seal 23, and the mouth ring seal has a plurality of small air sealing teeth 24.

[0027] The outlet baffle is inlaid with a balance drum seal 25, and the balance drum seal has multiple atmospheric sealing teeth 26. The interstage seal adopts a labyrinth seal inlaid with air sealing plates, and the air seals at both ends adopt dry gas seals, which can ensure the sealing requirements under high pressure difference and ensure that CO2 does not leak.

Claims

1. A large-capacity single-shaft multi-stage supercritical CO2 centrifugal compressor, comprising: The main shaft, cylinder body and end cover are characterized in that: the end cover is fixed to the cylinder body by tightening bolts, the main shaft is equipped with multi-stage impellers and multi-stage spacers using a red sleeve, the adjacent two stages of impellers are separated by spacers, and the main shaft is equipped with a balance drum using a red sleeve and tightened by a lock nut; An air inlet baffle, an air outlet baffle and a multi-stage baffle are installed in the cylinder body, and the multi-stage baffle is located between the impellers of two adjacent stages; The air outlet baffle is fastened to the outlet side end cover by bolts, and a variable cross-section flow channel is arranged between the baffle of the last stage and the air outlet baffle.

2. A large-capacity single-shaft multi-stage supercritical CO2 centrifugal compressor according to claim 1, characterized in that: An air inlet and an air outlet are installed on the cylinder body. The air inlet is located at the air inlet baffle, and the air outlet is located at the air outlet baffle.

3. The large-capacity single-shaft multi-stage supercritical CO2 centrifugal compressor according to claim 2, characterized in that: A thrust plate is installed at one end of the main shaft. The thrust plate and the main shaft are matched with each other in a taper and are locked by a nut.

4. The large-capacity single-shaft multi-stage supercritical CO2 centrifugal compressor according to claim 3 is characterized by: The air inlet partition and the multi-stage partitions are respectively inlaid with a mouth ring seal, and the mouth ring seal has a plurality of small air sealing teeth.

5. The large-capacity single-shaft multi-stage supercritical CO2 centrifugal compressor according to claim 4 is characterized by: The air outlet baffle is inlaid with a balance drum seal, and the balance drum seal is provided with a plurality of atmospheric sealing teeth.

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