Multi-stage throttling propane centrifugal refrigeration system

Abstract

The utility model relates to the technical field of refrigeration, and discloses a multistage throttling propane centrifugal refrigeration system which comprises a low-pressure propane suction tank, a medium-pressure propane suction tank, a high-pressure propane suction tank, a propane centrifugal compressor, a propane condenser, a propane condensate collecting tank, a user I, a user II, a user III, a propane medium-pressure circulation tank and a propane low-pressure circulation tank. The propane low-pressure circulating tank, the low-pressure propane suction tank, the propane centrifugal compressor, the propane condenser and the propane condensate collecting tank are sequentially connected, the high-pressure propane suction tank is respectively connected with a user I, a user II and a user III, and the medium-pressure propane suction tank is respectively connected with the propane medium-pressure circulating tank and the propane low-pressure circulating tank. The utility model solves the problems of poor refrigeration effect, poor stability and the like in the prior art.

Description

Technical Field

[0001] The utility model relates to the technical field of refrigeration, in particular to a multi-stage throttling propane centrifugal refrigeration system. Background Art

[0002] The commonly used refrigerants in natural gas ground processing projects are hydrocarbons, such as propane, propylene, ethane, ethylene, etc. Propane has many advantages as a refrigerant. In recent years, my country's newly built natural gas processing plants mostly use propane centrifugal refrigeration and mixed refrigerant refrigeration. Generally, propane centrifugal refrigeration can cool the raw natural gas to -38℃, achieving the purpose of low-temperature dehydrogenation of natural gas.

[0003] However, the overall processing flow of natural gas processing plants with many products is relatively long, the cooling demand is large and the temperature is inconsistent. If low temperature is used for cooling, the economic efficiency is poor. In addition, the fluctuation is large due to external factors, which is not conducive to the stable operation of the system. Utility Model Content

[0004] In order to overcome the deficiencies of the prior art, the utility model provides a multi-stage throttling propane centrifugal refrigeration system to solve the problems of poor refrigeration effect and poor stability in the prior art.

[0005] The technical solution adopted by the utility model to solve the above problems is:

[0006] A multi-stage throttling propane centrifugal refrigeration system comprises a low-pressure propane suction tank, a medium-pressure propane suction tank, a high-pressure propane suction tank, a propane centrifugal compressor, a propane condenser, a propane condensate collecting tank, a user I, a user II, a user III, a propane medium-pressure circulation tank, and a propane low-pressure circulation tank. The propane low-pressure circulation tank, the low-pressure propane suction tank, the propane centrifugal compressor, the propane condenser, and the propane condensate collecting tank are connected in sequence, the high-pressure propane suction tank is connected to the user I, the user II, and the user III respectively, and the medium-pressure propane suction tank is connected to the propane medium-pressure circulation tank and the propane low-pressure circulation tank respectively.

[0007] As a preferred technical solution, the medium-pressure propane suction tank is connected to user II and user III respectively.

[0008] As a preferred technical solution, a propane condensate collection tank, a high-pressure propane suction tank, and a propane centrifugal compressor are connected in sequence.

[0009] As a preferred technical solution, a propane condensate collection tank, user I, a high-pressure propane suction tank, and a propane centrifugal compressor are connected in sequence.

[0010] As a preferred technical solution, the high-pressure section, the propane condensate collection tank, the user I, the bottom of the high-pressure propane suction tank, and the propane centrifugal compressor are connected in sequence.

[0011] As a preferred technical solution, the high-pressure propane suction tank, user II, user III, and medium-pressure propane suction tank are connected in sequence, and the high-pressure propane suction tank is connected to the propane medium-pressure circulation tank.

[0012] As a preferred technical solution, it also includes user IV, a propane medium-pressure circulation tank, user IV, a medium-pressure propane suction tank, and a propane centrifugal compressor connected in sequence.

[0013] As a preferred technical solution, a high-pressure propane suction tank, user II, user III, a medium-pressure propane suction tank, and a propane medium-pressure circulation tank are connected in sequence.

[0014] As a preferred technical solution, it also includes user IV, the liquid phase outlet of the propane low-pressure circulation tank is connected to the inlet of user IV, and the outlet of user IV is connected to the inlet of the propane low-pressure circulation tank.

[0015] As a preferred technical solution, it also includes user IV, the liquid phase outlet of the propane medium-pressure circulation tank is connected to the inlet of user IV, and the outlet of user IV is connected to the inlet of the propane medium-pressure circulation tank.

[0016] Compared with the prior art, the utility model has the following beneficial effects:

[0017] (1) The utility model uses multi-stage throttling refrigeration to accurately match the temperature requirements of the user end, and can provide cooling capacity at multiple temperature levels, including (15-22°C, -13--18°C, -36--38°C), while reducing the energy consumption of the compressor under the premise of meeting the cooling capacity and temperature;

[0018] (2) The propane condensate collection tank, high-pressure propane suction tank, medium-pressure propane suction tank, propane medium-pressure circulation tank, and propane low-pressure circulation tank of the utility model can all store propane, and the system has strong anti-fluctuation capability. The liquid propane in the propane low-pressure circulation tank can be supplied by the propane medium-pressure circulation tank, and the operation is flexible;

[0019] (3) In the present utility model, users I, II and III can all be used as subcooling economizers, thereby improving the adaptability of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a schematic diagram of the system structure of the utility model in which users II and III are the cooling demand ends;

[0021] Figure 2 This is a schematic diagram of the system structure in which users I, II and III of the utility model serve as subcoolers.

[0022] Marks and their corresponding names in the attached drawings: 1. Low-pressure propane suction tank, 2. Medium-pressure propane suction tank, 3. High-pressure propane suction tank, 4. Propane centrifugal compressor, 5. Propane condenser, 6. Propane condensate collection tank, 7. User I, 8. User II, 9. User III, 10. Propane medium-pressure circulation tank, 11. Propane low-pressure circulation tank, 12. Propane recovery pump, 13. User IV. DETAILED DESCRIPTION

[0023] The present invention will be further described in detail below in conjunction with the embodiments and drawings, but the implementation manner of the present invention is not limited thereto.

[0024] It is worth explaining that: in the present utility model, the low pressure, medium pressure and high pressure in the low-pressure propane suction tank 1, the medium-pressure propane suction tank 2 and the high-pressure propane suction tank 3 are merely the pressures compared among the three (i.e. the operating pressures of the propane suction tanks are in the following relationship: low-pressure propane suction tank 1 < medium-pressure propane suction tank 2 < high-pressure propane suction tank 3), and are not limited to a certain range; in the present utility model, the low pressure and medium pressure in the propane medium-pressure circulation tank 10 and the propane low-pressure circulation tank 11 are merely the pressures compared among the two (i.e. the operating pressures of the circulation tanks are in the following relationship: propane low-pressure circulation tank 11 < propane medium-pressure circulation tank 10), and are not limited to a certain range.

[0025] Example 1

[0026] like Figure 1 to Figure 2 As shown, the utility model relates to a multi-stage throttling propane centrifugal refrigeration system. The system includes a propane centrifugal compressor, a propane condenser, a propane condensate collection tank, user I, user II, user III, user IV, a propane medium-pressure circulation tank, a propane low-pressure circulation tank, a high-pressure propane suction tank, a medium-pressure propane suction tank, a low-pressure propane suction tank and a propane recovery pump. The utility model can provide cooling capacity at multiple temperature levels (including 15 to 22°C, -13 to -18°C, and -36 to -38°C). The utility model is aimed at refrigeration systems with complex working conditions and frequent fluctuations. It adopts multi-stage centrifugal pressurization, multi-stage throttling refrigeration, and multiple liquid storage modules. Under the premise of meeting the needs of users at each temperature level, the system operates stably. At the same time, users I, users II, and users III can generate supercooled propane liquid for downstream use through propane self-heat exchange, thereby improving system flexibility and reducing compressor power.

[0027] A multi-stage throttling propane centrifugal refrigeration system comprises a propane centrifugal compressor 4, a propane condenser 5, a propane condensate collecting tank 6, a user I7, a user II8, a user III9, a propane medium-pressure circulation tank 10, a propane low-pressure circulation tank 11, a high-pressure propane suction tank 3, a medium-pressure propane suction tank 2, a low-pressure propane suction tank 1, and a user IV13; the outlet of the compressor 4 is connected to the propane condenser 5, the outlet of the propane condenser 5 is connected to the propane condensate collecting tank 6, the outlet of the propane condensate collecting tank 6 is connected to the user I7, and the outlet of the user I7 is connected to the high-pressure propane suction tank 3; the outlet of the propane condensate collecting tank 6 is connected to the high-pressure propane suction tank 3, the outlet of the high-pressure propane suction tank 3 is connected to the user II8, and the outlet of the user II8 is connected to the high-pressure propane suction tank 3. It is connected to the medium-pressure propane suction tank 2; the outlet of the high-pressure propane suction tank 3 is connected to the user III 9, and the outlet of the user III 9 is connected to the medium-pressure propane suction tank 2; the outlet of the high-pressure propane suction tank 3 is connected to the propane medium-pressure circulation tank 10, and the outlet of the propane medium-pressure circulation tank 10 is connected to the propane low-pressure circulation tank 11; the outlet of the propane medium-pressure circulation tank 10 is connected to the medium-pressure propane suction tank 2, and the outlet of the medium-pressure propane suction tank 2 is connected to the propane low-pressure circulation tank 11; the outlet of the propane low-pressure circulation tank 11 is connected to the low-pressure propane suction tank 1, and the outlet of the low-pressure propane suction tank 1 is connected to the propane centrifugal compressor 4; the outlet of the medium-pressure propane suction tank 2 is connected to the propane centrifugal compressor 4; the outlet of the high-pressure propane suction tank 3 is connected to the propane centrifugal compressor 4.

[0028] Preferably, the outlet of the propane centrifugal compressor 4 is connected to the propane condensate collection tank 6 through a pipeline.

[0029] Preferably, the gaseous propane at the outlet of the propane centrifugal compressor 4 is first condensed into liquid propane through a propane condenser 5 and enters a propane condensate collection tank 6 .

[0030] Preferably, part of the propane in the propane condensate collection tank 6 is throttled into the user I7, and the other part is throttled into the high-pressure propane suction tank 3.

[0031] Preferably, the liquid propane in the high-pressure propane suction tank 3 enters user II 8 , user III 9 , and propane medium-pressure circulation tank 10 after throttling, and the gaseous propane in the high-pressure propane suction tank 3 enters the third-stage suction of the propane centrifugal compressor 4 .

[0032] Preferably, the gas phase outlet of the propane medium-pressure circulation tank 10, the gas phase outlet of user II 8, and the gas phase outlet of user III 9 are connected to the inlet of the medium-pressure propane suction tank 2, the liquid phase outlet of the medium-pressure propane suction tank 2 is connected to the propane low-pressure circulation tank 11, and the gas phase outlet of the medium-pressure propane suction tank 2 enters the secondary suction of the propane centrifugal compressor 4.

[0033] Preferably, the liquid phase outlet of the propane medium-pressure circulation tank 10 is connected to the propane low-pressure circulation tank 11 after throttling.

[0034] Preferably, the gas phase outlet of the propane low-pressure circulation tank 11 is connected to the inlet of the low-pressure propane suction tank 1 , and the gas phase outlet of the low-pressure propane suction tank 1 enters the first-stage suction of the propane centrifugal compressor 4 .

[0035] Preferably, the liquid phase outlet of the propane low-pressure circulation tank 11 is connected to the inlet of the user IV 13 , and the outlet of the user IV 13 is connected to the inlet of the propane low-pressure circulation tank 11 .

[0036] Preferably, the liquid phase outlet of the propane medium-pressure circulation tank 10 is connected to the inlet of the user IV 13 , and the outlet of the user IV 13 is connected to the inlet of the propane medium-pressure circulation tank 10 .

[0037] Example 2

[0038] Combination Figure 1 As shown, the utility model is a multi-stage throttling propane centrifugal refrigeration system, including a propane centrifugal compressor 4, a propane condenser 5, a propane condensate collection tank 6, a user I7, a user II8, a user III9, a propane medium-pressure circulation tank 10, a propane low-pressure circulation tank 11, a high-pressure propane suction tank 3, a medium-pressure propane suction tank 2, a low-pressure propane suction tank 1, and a user IV13. A multi-stage throttling propane centrifugal refrigeration system is mainly divided into four parts, including a compressor exhaust part, a high-pressure section part, a medium-pressure section part and a low-pressure section part.

[0039] The exhaust part of the compressor is pressurized to 1500kPa-1800kPa by the propane centrifugal compressor 4, and the propane at 60℃-75℃ enters the propane condenser 5 to be cooled to (40℃-50℃), and then enters the propane condensate collection tank 6.

[0040] In the high-pressure section, a part of the propane at 1450 kPa to 1750 kPa (40°C to 50°C) in the propane condensate collecting tank 6 is throttled to 730 kPa to 900 kPa (15°C to 22°C) and enters the user I7 to provide cooling capacity, and returns to the high-pressure propane suction tank 3 after gasification, and another part of the propane is directly throttled to 730 kPa to 900 kPa (15°C to 22°C) and enters the bottom of the high-pressure propane suction tank 3. Further, the gaseous propane at 730 kPa to 900 kPa (15°C to 22°C) in the high-pressure propane suction tank 3 enters the propane centrifugal compressor 4 as the third-stage suction of the compressor.

[0041] In the medium-pressure section, the liquid phase of the high-pressure propane suction tank 3 passes through the throttle valve, is throttled to 260-310 kPa (-18°C to -13°C) and enters the shell side of user II8 and user III9, and returns to the inlet of the medium-pressure propane suction tank 2 after heat exchange in the reboiler and vaporization. The remaining liquid phase of the high-pressure propane suction tank 3 is throttled to 260-310 kPa (-18°C to -13°C) and enters the propane medium-pressure circulation tank 10. Further, the propane in the propane medium-pressure circulation tank 10 enters the user IV13 circulation gasification to provide cooling capacity, and the vaporized propane enters the inlet of the medium-pressure propane suction tank 2. The gaseous propane 260-310 kPa (-18°C to -13°C) of the medium-pressure propane suction tank 2 enters the propane centrifugal compressor 4 as the secondary suction of the compressor.

[0042] In the low-pressure section, the liquid propane in the medium-pressure propane suction tank 2 and the propane medium-pressure circulation tank 10 is throttled to 121Kpa~132Kpa (-38℃~-36℃) through the throttle valve and enters the propane low-pressure circulation tank 11. Further, the propane in the propane low-pressure circulation tank 11 enters the user IV13 circulation gasification to provide cold capacity, and the gasified propane enters the inlet of the low-pressure propane suction tank 1. The gaseous propane 121Kpa~132Kpa (-38℃~-36℃) in the low-pressure propane suction tank 1 enters the propane centrifugal compressor 4 as the first-stage suction of the compressor. The propane centrifugal refrigeration cycle is completed.

[0043] Example 3

[0044] This embodiment provides a more detailed implementation method based on Embodiment 2.

[0045] Combination Figure 2 , the utility model is further explained.

[0046] In the high-pressure section, a part of the propane at 1450kPa to 1750kPa (40°C to 50°C) in the propane condensate collecting tank 6 is throttled to 730kPa to 900kPa (15°C to 22°C) and enters the user I7 shell side to provide cooling capacity, and returns to the high-pressure propane suction tank 3 after being vaporized. Another part is drawn into the user I7 pipe side and is cooled, then merged with the other part of the propane, and is directly throttled to 730kPa to 900kPa and enters the bottom of the high-pressure propane suction tank 3.

[0047] In the medium-pressure section, part of the liquid phase of the high-pressure propane suction tank 3 passes through the throttle valve, is throttled to 260-310 kPa (-18°C--13°C), enters the shell side of user II8 and user III9, and is returned to the inlet of the medium-pressure propane suction tank 2 after heat exchange in the reboiler and gasification. Another part of the liquid phase propane of the high-pressure propane suction tank 3 directly enters the tube side of user II8 and user III9 after supercooling, and then merges with the remaining liquid phase of the high-pressure propane suction tank 3 and is throttled to 260-310 kPa to enter the propane medium-pressure circulation tank 10.

[0048] As described above, the utility model can be implemented well.

[0049] The above is only a preferred embodiment of the utility model and does not limit the utility model in any form. According to the technical essence of the utility model, within the spirit and principles of the utility model, any simple modification, equivalent replacement and improvement made to the above embodiment still falls within the protection scope of the technical solution of the utility model.

Claims

1. A multi-stage throttling propane centrifugal refrigeration system, characterized in that: The invention comprises a low-pressure propane suction tank (1), a medium-pressure propane suction tank (2), a high-pressure propane suction tank (3), a propane centrifugal compressor (4), a propane condenser (5), a propane condensate collecting tank (6), a user I (7), a user II (8), a user III (9), a propane medium-pressure circulation tank (10), and a propane low-pressure circulation tank (11). The propane low-pressure circulation tank (11), the low-pressure propane suction tank (1), the propane centrifugal compressor (4), the propane condenser (5), and the propane condensate collecting tank (6) are connected in sequence, the high-pressure propane suction tank (3) is connected to the user I (7), the user II (8), and the user III (9) respectively, and the medium-pressure propane suction tank (2) is connected to the propane medium-pressure circulation tank (10) and the propane low-pressure circulation tank (11) respectively.

2. A multi-stage throttling propane centrifugal refrigeration system according to claim 1, characterized in that: The medium-pressure propane suction tank (2) is connected to user II (8) and user III (9) respectively.

3. A multi-stage throttling propane centrifugal refrigeration system according to claim 1 or 2, characterized in that: The propane condensate collecting tank (6), the high-pressure propane suction tank (3) and the propane centrifugal compressor (4) are connected in sequence.

4. A multi-stage throttling propane centrifugal refrigeration system according to claim 1 or 2, characterized in that: The propane condensate collecting tank (6), the user I (7), the high-pressure propane suction tank (3), and the propane centrifugal compressor (4) are connected in sequence.

5. A multi-stage throttling propane centrifugal refrigeration system according to claim 4, characterized in that: The propane condensate collecting tank (6), the user I (7), the bottom of the high-pressure propane suction tank (3), and the propane centrifugal compressor (4) are connected in sequence.

6. A multi-stage throttling propane centrifugal refrigeration system according to claim 1 or 2, characterized in that: The high-pressure propane suction tank (3), user II (8), user III (9), and medium-pressure propane suction tank (2) are connected in sequence, and the high-pressure propane suction tank (3) is connected to the propane medium-pressure circulation tank (10).

7. A multi-stage throttling propane centrifugal refrigeration system according to claim 6, characterized in that: It also includes a user IV (13), a propane medium-pressure circulation tank (10), a user IV (13), a medium-pressure propane suction tank (2), and a propane centrifugal compressor (4), which are connected in sequence.

8. A multi-stage throttling propane centrifugal refrigeration system according to claim 1 or 2, characterized in that: The high-pressure propane suction tank (3), user II (8), user III (9), medium-pressure propane suction tank (2), and propane medium-pressure circulation tank (10) are connected in sequence.

9. A multi-stage throttling propane centrifugal refrigeration system according to claim 1 or 2, characterized in that: It also includes a user IV (13), the liquid phase outlet of the propane low-pressure circulation tank (11) is connected to the inlet of the user IV (13), and the outlet of the user IV (13) is connected to the inlet of the propane low-pressure circulation tank (11).

10. A multi-stage throttling propane centrifugal refrigeration system according to claim 1 or 2, characterized in that: It also includes a user IV (13), the liquid phase outlet of the propane medium-pressure circulation tank (10) is connected to the inlet of the user IV (13), and the outlet of the user IV (13) is connected to the inlet of the propane medium-pressure circulation tank (10).

Images