Two-stage single-screw compressor stable-pressure operation system
The two-stage single-screw compressor pressure stabilization system, which combines a fixed-frequency motor and a variable-frequency motor, utilizes a buffer tank and a multi-way reflux regulating valve design to solve the problem of sudden pressure drop at startup, achieving stable system operation and efficient pressure regulation, and improving equipment reliability and maintenance efficiency.
Patent Information
- Application Number
- CN202520347591.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-03
- Publication Date
- 2026-02-13
- Estimated Expiration
- 2035-03-03
AI Technical Summary
The existing two-stage single-screw compressor experiences a sudden increase in intake volume at startup, which causes a sharp drop in intake pressure, affecting stable operation. Fluctuations in process gas volume exacerbate system instability and may even trigger shutdown protection. In particular, when the second-stage compressor shuts down, the first-stage compressor is also forced to shut down, affecting production continuity and increasing maintenance costs.
By combining fixed-frequency and variable-frequency motors, and through the design of buffer tanks and multi-way reflux regulating valves, low-frequency start-up and bypass pipeline gas filling are achieved, ensuring that the secondary compressor obtains sufficient gas at the moment of start-up. Combined with the PID reflux regulation mechanism, self-circulation operation is achieved, reducing external nitrogen consumption, and excellent pressure regulation capability is provided to ensure system stability.
It achieves a smooth transition during compressor startup, avoids problems with excessively low intake pressure, reduces nitrogen consumption, ensures stable system operation, and improves equipment reliability and maintenance efficiency. In particular, it allows the primary compressor to operate independently when the secondary compressor stops, facilitating maintenance or troubleshooting.
Smart Images
Figure CN223908386U_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The utility model relates to a compressor technical field more specifically, the utility model relates to a two-stage single screw compressor stable operation system. BACKGROUND
[0002] The two-stage single screw compressor stable operation system adopts two-stage compression technology, through the special design in the single screw compressor, preliminary compression is carried out in the first stage, and the gas is further compressed to the required pressure in the second stage. This way effectively reduces the temperature in the compression process, improves the reliability and stability of the compressor. At the same time, the system is equipped with a pressure stabilizing device, which can monitor and control the output pressure to ensure that it fluctuates within the set range, so as to realize stable operation and keep the output pressure constant. The two-stage single screw compressor stable operation system in the prior art has the following problems, especially at the start-up moment of the second-stage compressor, the suction volume increases dramatically, which often leads to a sharp drop in the intake pressure, lower than the normal starting level, affecting stable operation. In addition, the significant fluctuation of process gas volume further aggravates the instability of the system. When the fluctuation is large, the intermediate end pressure between the two-stage compressors is easy to be unbalanced, and even the problem of low first-stage intake pressure may be caused, which in turn triggers the shutdown protection mechanism. More troublesome is that when the second-stage compressor is shut down, due to the insufficient stability of the whole system, the first-stage compressor is often forced to shut down as well, which not only affects the production continuity, but also increases the operation and maintenance cost. SUMMARY
[0003] In order to overcome the shortcomings of the prior art, the utility model provides a two-stage single screw compressor stable operation system, which has the advantages of stability of process gas volume.
[0004] In order to achieve the above-mentioned purpose, the utility model provides the following technical scheme: a two-stage single screw compressor stable operation system, comprising a fixed-frequency motor, a variable-frequency motor, a first-stage compressor and a second-stage compressor, the output of the fixed-frequency motor is fixedly connected with the first-stage compressor, the output end of the variable-frequency motor is fixedly connected with the second-stage compressor, the top of the first-stage compressor is provided with a first-stage compressor inlet, the first-stage compressor inlet is connected with a buffer tank through a backflow regulating valve one, the bottom of the first-stage compressor is provided with a first-stage compressor outlet, the bottom of the first-stage compressor outlet is provided with a check valve one and a minimum pressure valve, one end of the minimum pressure valve is connected with the buffer tank.
[0005] As a preferred technical scheme of the utility model, the second-stage compressor is provided with a second-stage compressor inlet above, the second-stage compressor inlet is provided with a butterfly valve, one end of the butterfly valve is connected with the buffer tank, the butterfly valve and the buffer tank are connected through a bypass pipeline two, the bypass pipeline two comprises a hand valve one and an orifice plate, the second-stage compressor inlet and the second-stage compressor are connected through a pressure transmitter two and a needle valve two.
[0006] As a preferred technical scheme of the utility model, the inside of the buffer tank is provided with bypass pipeline one, bypass pipeline one includes hand valve two and check valve three, one end of hand valve two is connected with reflux regulating valve four, one end of reflux regulating valve four is connected with two-stage compressor outlet.
[0007] As a preferred technical scheme of the utility model, pressure transmitter three and needle valve three are arranged on the inlet of the first-stage compressor, the inlet of the first-stage compressor is connected with reflux regulating valve four through reflux regulating valve three, check valve one is connected with the outlet of the first-stage compressor through pressure transmitter one and needle valve one.
[0008] As a preferred technical scheme of the utility model, the buffer tank is connected with reflux regulating valve four through reflux regulating valve two, the two-stage compressor is connected with reflux regulating valve four through check valve two.
[0009] As a preferred technical scheme of the utility model, the two-stage compressor is connected with reflux regulating valve four through check valve two, check valve two is connected with the two-stage compressor through needle valve four and pressure transmitter four.
[0010] Compared with the prior art, the utility model has the advantages of the following:
[0011] The utility model realizes the low frequency starting and the bypass pipeline inflation function through the cooperation between low frequency starting and bypass pipeline, ensures that the two-stage compressor can obtain sufficient gas in the starting moment, realizes the smooth transition, avoids the problem that the inlet pressure is too low due to the too large instantaneous suction volume, the system pre-charges a certain amount of nitrogen, and realizes the self-circulation operation through the ingenious multi-way reflux regulating mechanism, effectively reduces the continuous consumption of external nitrogen, in addition, the system has excellent pressure regulating capacity, can rapidly and smoothly adjust the pressure fluctuation, ensures the stability of the overall operation, especially important is that when the two-stage compressor stops, the system can keep the independent operation of the first-stage compressor, provides the convenience for the independent maintenance or troubleshooting of the two-stage compressor, greatly improves the reliability and maintenance efficiency of the equipment. BRIEF DESCRIPTION OF DRAWINGS
[0012] Figure 1 It is the whole use flow diagram of the utility model.
[0013] In the diagram: 1. Fixed-frequency motor; 2. Needle valve one; 3. Needle valve two; 4. Needle valve three; 5. Needle valve four; 6. Pressure transmitter one; 7. Pressure transmitter two; 8. Pressure transmitter three; 9. Pressure transmitter four; 10. Reflux regulating valve one; 11. Reflux regulating valve two; 12. Reflux regulating valve three; 13. Reflux regulating valve four; 14. Check valve one; 15. Check valve two; 16. Check valve three; 17. Manual valve one; 18. Manual valve two; 19. Bypass line one; 20. Bypass line two; 21. Minimum pressure valve; 22. Buffer tank; 23. Variable-frequency motor; 24. Primary compressor; 25. Secondary compressor; 26. Primary compressor outlet; 27. Secondary compressor outlet; 28. Primary compressor inlet; 29. Secondary compressor inlet; 30. Butterfly valve; 31. Orifice plate. Detailed Implementation
[0014] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.
[0015] like Figure 1 As shown, this utility model provides a two-stage single-screw compressor pressure stabilization system, including a fixed-frequency motor 1, a variable-frequency motor 23, a first-stage compressor 24, and a second-stage compressor 25. The output of the fixed-frequency motor 1 is fixedly connected to the first-stage compressor 24, and the output of the variable-frequency motor 23 is fixedly connected to the second-stage compressor 25. The top of the first-stage compressor 24 is provided with a first-stage compressor inlet 28, which is connected to the buffer tank 22 through a reflux regulating valve 10. The bottom of the first-stage compressor 24 is provided with a first-stage compressor outlet 26, and the bottom of the first-stage compressor outlet 26 is provided with a check valve 14 and a minimum pressure valve 21. One end of the minimum pressure valve 21 is connected to the buffer tank 22.
[0016] The staff uses a fixed-frequency start method for the fixed-frequency motor 1. The process gas enters the first-stage compressor 24 through the pressure transmitter 38 and needle valve 34. After being pressurized by the first-stage compressor 24, the gas pressure is increased. Subsequently, the pressurized process gas passes through the check valve 14 and minimum pressure valve 21 at the outlet 26 of the first-stage compressor to ensure unidirectional gas flow and maintain the minimum discharge pressure of the first-stage compressor at no less than 0.5MPa. Part of the process gas flows directly to the outlet 27 of the second-stage compressor through the bypass line 19, check valve 316 and normally open hand valve 218 to supply gas to the downstream system. During this process, the return regulating valve 413 is required to remain normally open and not perform the back pressure control function to prevent the first-stage compressor from overloaded due to excessive pressure.
[0017] Since the bypass pipeline 19 and the pipeline of the secondary compressor outlet 27 are of the same specification, the bypass pipeline 19 cannot completely discharge all the process gas, resulting in a continuous rise in the pressure in the buffer tank 22. When the pressure transmitter 1 detects that the pressure in the buffer tank exceeds 0.7 MPaG, the control backflow regulating valve 10 starts the PID backflow regulating function to reduce the pressure in the buffer tank 22 by adjusting the opening of the backflow regulating valve 10. A small amount of process gas in the buffer tank 22 will slowly be compressed to 0.7 MPaG by the secondary compressor 25 system through the bypass pipeline 2, the normally open hand valve 1 and the orifice plate 3, so as to avoid dry grinding caused by the buffer tank 22 idling under strong gas flow;
[0018] Whether the secondary compressor 25 is started or not, the stable operation of the primary compressor 24 is crucial. When the pressure at the primary compressor inlet 28 is too low, the pressure transmitter 3 will timely detect the change and control the backflow regulating valve 3 to perform PID backflow regulation. By accurately adjusting the opening of the backflow regulating valve 3, the pressure at the primary compressor inlet 28 can be effectively stabilized, ensuring that the primary compressor 24 operates under stable conditions.
[0019] Among them, the secondary compressor 25 is provided with a secondary compressor inlet 29, the secondary compressor inlet 29 is provided with a butterfly valve 30, one end of the butterfly valve 30 is connected with the buffer tank 22, the butterfly valve 30 and the buffer tank 22 are connected through the bypass pipeline 2, the bypass pipeline 2 comprises a hand valve 1 and an orifice plate 3, and the secondary compressor inlet 29 and the secondary compressor 25 are provided with a pressure transmitter 2 and a needle valve 3.
[0020] The motor of the secondary compressor 25 is a variable frequency motor 3, and the frequency range is between 20-50 Hz, which is usually manually set to 20 Hz to start. After starting, the secondary compressor 25 starts to operate, and the butterfly valve 30 is opened, so that the process gas in the buffer tank 22 is sucked in and pressurized. In order to ensure stable operation, when the inlet pressure of the secondary compressor 25 is lower than 0.65 MPaG, the pressure transmitter 2 will start the PID backflow regulation to maintain the inlet pressure stable at 0.65 MPaG by controlling the pressure transmitter 2. The pressure transmitter 4 and the needle valve 5 control the backflow regulating valve 4 through PID regulation to ensure that the exhaust pressure of the secondary compressor outlet 27 is stable at 2.2 MPaG. At this time, the entire outlet pipeline of the secondary compressor 25 is full of 2.2 MPaG process gas, so the process gas in the buffer tank no longer flows through the bypass pipeline 1, but is effectively prevented from backflowing to the buffer tank by the check valve 3, ensuring the stable operation of the system.
[0021] The inside of the buffer tank 22 is provided with a bypass pipeline I 19, the bypass pipeline I 19 comprises a hand valve II 18 and a check valve III 16, one end of the hand valve II 18 is connected with a backflow regulating valve IV 13, one end of the backflow regulating valve IV 13 is connected with a secondary compressor outlet 27.
[0022] When part of the gas is discharged through the bypass pipeline I 19, it can ensure that the backflow regulating valve I 10 does not fully 100% backflow, so that when the secondary compressor 25 starts, the backflow regulating valve I can respond quickly, effectively preventing the secondary compressor 25 from stopping due to the excessively low inlet pressure; secondly, since the gas flow of the bypass pipeline I 19 is large, it can preferentially fill the back end of the check valve II 15 with process gas reaching 0.7 MPaG, ensuring that when the process gas enters the secondary compressor 25 through the bypass pipeline II 20, the hand valve I and the orifice plate 31, the secondary compressor 25 will not be in an idle state, avoiding the occurrence of dry grinding.
[0023] The primary compressor inlet 28 is provided with a pressure transmitter III 8 and a needle valve III 4, the primary compressor inlet 28 is connected with the backflow regulating valve IV 13 through the backflow regulating valve III 12, the check valve I 14 is connected with the primary compressor outlet 26 through the pressure transmitter I 6 and the needle valve I 2;
[0024] When the frequency conversion motor 23 is manually adjusted step by step, the gas processing capacity increases, and reaches full load operation at 50 Hz, in this process, the backflow regulating valve I 10 and the backflow regulating valve II 11 gradually tend to be fully closed, while the backflow regulating valve III 12 is PID regulated according to the gas inlet condition of the primary compressor 24, at the same time, the backflow regulating valve IV 13 is gradually opened to an appropriate degree, to ensure that the exhaust pressure of the secondary compressor 25 is stable at 2.2 MPaG, so as to realize the stable operation of the system.
[0025] The buffer tank 22 is connected with the backflow regulating valve IV 13 through the backflow regulating valve II 11, and the secondary compressor 25 is connected with the backflow regulating valve IV 13 through the check valve II 15.
[0026] The frequency of the secondary compressor 25 is adjusted manually to avoid overlapping with the function of the backflow regulating valve II 11, to ensure the stability of the automatic regulation of the gas capacity, if the gas inlet capacity of the primary compressor 24 decreases, the backflow regulating valve III 12 will be opened accordingly, at this time, the frequency of the secondary compressor 25 is manually adjusted to be low, to reduce the gas consumption and achieve the energy saving effect, to ensure the economy and stability of the system operation.
[0027] The secondary compressor 25 is connected with the backflow regulating valve IV 13 through the check valve II 15, and the check valve II 15 is connected with the secondary compressor 25 through the needle valve IV 5 and the pressure transmitter IV 9.
[0028] When the primary compressor 24 and the secondary compressor 25 system is shut down or the secondary compressor is shut down due to failure, the operation sequence is to stop the secondary compressor 25 first, at this time, the needle valve two 3 is closed, the backflow regulating valve four 13 is fully opened to release pressure, the backflow regulating valve two 11 is fully closed to prevent backflow, and the backflow regulating valve three 12 is PID regulated according to the pressure transmitter three 8 of the primary compressor 24 to maintain system stability, at the same time, the backflow regulating valve one 10 is automatically PID regulated according to the feedback of the exhaust pressure transmitter one 6 and the needle valve one 2, so that the gas in the buffer tank 22 continues to supply downstream through the bypass pipeline one 19, ensuring the stable operation of the primary compressor 24, in this state, the primary compressor 24 can be selected to be stopped or the secondary compressor 25 is restarted, if the primary compressor 24 is directly or fails to shut down, the secondary compressor 25 will also stop running. Among them, the check valve one 14 and the check valve two 15 in the system play a key role, which can effectively prevent the backflow of high-pressure gas when the primary compressor 24 and the secondary compressor 25 are shut down, avoid the reverse rotation of the primary compressor 24 and the secondary compressor 25, and thus protect the primary compressor 24 and the secondary compressor 25 from being damaged.
[0029] The working principle and use process of the utility model:
[0030] The staff adopts the fixed-frequency starting mode of the fixed-frequency motor 1, the process gas enters the primary compressor 24 from the pressure transmitter three 8 and the needle valve three 4, after the pressurization of the primary compressor 24, the gas pressure is improved, then the pressurized process gas passes through the check valve one 14 of the primary compressor outlet 26 and the minimum pressure valve 21, ensuring the one-way flow of the gas and maintaining the minimum exhaust pressure of the primary compressor not less than 0.5MPa, part of the process gas directly flows to the secondary compressor outlet 27 through the bypass pipeline one 19, the check valve three 16 and the normally open hand valve two 18, and supplies gas to the downstream system, in this process, it is required that the backflow regulating valve four 13 remains in the normally open state and does not perform the back pressure control function, so as to prevent the primary compressor from being overloaded due to excessive pressure;
[0031] Since the bypass pipeline one 19 and the pipeline of the secondary compressor outlet 27 are of the same specification, the bypass pipeline one 19 cannot completely discharge all the process gas, resulting in the continuous rise of the pressure in the buffer tank 22, when the pressure transmitter one 6 detects that the pressure in the buffer tank exceeds 0.7MPaG, the backflow regulating valve one 10 is controlled to start the PID backflow regulating function, and the pressure in the buffer tank 22 is reduced through the opening of the backflow regulating valve one 10, a small amount of process gas in the buffer tank 22 will pass through the bypass pipeline two 20, the normally open hand valve one 17 and the orifice plate 31, and slowly stamp the secondary compressor 25 system to 0.7MPaG, so as to avoid the dry grinding phenomenon caused by the idling of the buffer tank 22 under the strong gas flow;
[0032] Whether the secondary compressor 25 is started or not, the stable operation of the primary compressor 24 is crucial, when the primary compressor inlet 28 pressure is too low, the pressure transmitter three 8 can detect the change in time and control the backflow regulating valve three 12 to carry out PID backflow regulation, by accurately adjusting the opening of the backflow regulating valve three 12, the pressure of the primary compressor inlet 28 can be effectively stabilized, and the primary compressor 24 can be ensured to operate under stable working conditions.
[0033] It should be noted that, in this paper, relational terms such as first and second and the like are used merely to distinguish one entity or action from another, without necessarily requiring or implying that there is any such actual relationship or order between such entities or actions. Moreover, the terms "comprises", "comprising", or any other variations thereof, are intended to cover a non-exclusive inclusion, so that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but can also include other elements not expressly listed or inherent to such process, method, article, or apparatus.
[0034] Although the embodiments of the present application have been shown and described, it is to be understood that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present application, the scope of which is defined by the appended claims and their equivalents.
Claims
1. A two-stage single-screw compressor steady operation system, comprising a fixed-frequency motor (1), a variable-frequency motor (23), a first-stage compressor (24) and a second-stage compressor (25), characterized in that: The output of the fixed frequency motor (1) is fixedly connected with the primary compressor (24), the output end of the variable frequency motor (23) is fixedly connected with the secondary compressor (25), the top of the primary compressor (24) is provided with a primary compressor inlet (28), the primary compressor inlet (28) and the buffer tank (22) are connected through a reflux regulating valve one (10), the bottom of the primary compressor (24) is provided with a primary compressor outlet (26), the bottom of the primary compressor outlet (26) is provided with a check valve one (14) and a minimum pressure valve (21), one end of the minimum pressure valve (21) is connected with the buffer tank (22).
2. The two-stage single-screw compressor pressure stabilization system of claim 1, wherein: The secondary compressor (25) is provided with a secondary compressor inlet (29) above, the secondary compressor inlet (29) is provided with a butterfly valve (30), one end of the butterfly valve (30) is connected with the buffer tank (22), the butterfly valve (30) and the buffer tank (22) are connected through a bypass pipeline two (20), the bypass pipeline two (20) comprises a hand valve one (17) and an orifice plate (31), the secondary compressor inlet (29) and the secondary compressor (25) are connected through a pressure transmitter two (7) and a needle valve two (3).
3. The two-stage single screw compressor pressure stabilization system of claim 1, wherein: The inside of the buffer tank (22) is provided with a bypass pipeline one (19), the bypass pipeline one (19) comprises a hand valve two (18) and a check valve three (16), one end of the hand valve two (18) is connected with a reflux regulating valve four (13), one end of the reflux regulating valve four (13) is connected with a secondary compressor outlet (27).
4. The two-stage single screw compressor pressure stabilization system of claim 1, wherein: The primary compressor inlet (28) is provided with a pressure transmitter three (8) and a needle valve three (4), the primary compressor inlet (28) and the reflux regulating valve four (13) are connected through a reflux regulating valve three (12), the check valve one (14) and the primary compressor outlet (26) are connected through a pressure transmitter one (6) and a needle valve one (2).
5. The two-stage single screw compressor pressure stabilization system of claim 1, wherein: The buffer tank (22) and the reflux regulating valve four (13) are connected through a reflux regulating valve two (11), the secondary compressor (25) and the reflux regulating valve four (13) are connected through a check valve two (15).
6. The two-stage single screw compressor pressure stabilization system of claim 1, wherein: The secondary compressor (25) and the reflux regulating valve four (13) are connected through a check valve two (15), the check valve two (15) and the secondary compressor (25) are connected through a needle valve four (5) and a pressure transmitter four (9).