Double-working-condition semi-falling-film low-temperature refrigerating unit

Abstract

The utility model discloses a double-working-condition semi-falling-film low-temperature refrigerating unit, and belongs to the technical field of refrigeration. Comprising a compressor, an oil separator, a condenser, an expansion valve and a semi-falling film heat exchanger which are sequentially connected, an oil cooler is arranged between the oil separator and the compressor, the oil separator is further connected with the semi-falling film heat exchanger, and the semi-falling film heat exchanger comprises a heat exchanger shell and a heat exchanger heat exchange pipe arranged in the heat exchanger shell. An oil heat exchange pipe is arranged in the bath type heat exchange area, one end of the oil heat exchange pipe is connected with an oil outlet of the oil separator, and the other end of the oil heat exchange pipe supplies oil to the compressor. Under the low-load working condition, the amount of gas to be treated is small, the temperature of a liquid refrigerant in the semi-falling film heat exchanger is still low, oil is directly cooled through the low-temperature refrigerant in the bath type heat exchange area, and the cooled oil returns to the compressor, so that the oil cooler can work intermittently, energy consumption is reduced, and the service life of the oil cooler is prolonged. And the service life of the oil cooler is prolonged.

Description

Technical Field

[0001] A dual-condition semi-falling film cryogenic refrigeration unit belongs to the field of refrigeration technology. Background Technology

[0002] Organic waste gases generated during chemical processes need to be treated with activated carbon or combusted before being emitted. Typically, before activated carbon treatment and combustion, at least two stages of precooling and deep cooling are required. Currently, direct cooling is commonly used to condense waste gases. For example, CN114279102A discloses a falling film evaporative cooling system and its operating method, including a compressor, an oil separator connected to the compressor's exhaust port, an evaporative condenser connected to the oil separator's outlet, a liquid storage tank connected to the evaporative condenser's outlet, a throttling device connected to the liquid storage tank's outlet, and a falling film evaporator connected to the throttling device's outlet. The gaseous refrigerant outlet of the falling film evaporator is connected to the compressor's return port. The high-temperature, high-pressure refrigerant gas compressed by the screw compressor enters the oil separator, which separates the refrigeration oil from the high-pressure refrigerant vapor discharged from the screw compressor. The refrigerant gas from the oil separator is condensed into high-pressure refrigerant liquid by the evaporative condenser. After being throttled and depressurized by the throttling device, it enters the falling film evaporator. In the falling film evaporator, the refrigerant evaporates and exchanges heat with the waste gas and other media, and then the refrigerant gas returns to the compressor.

[0003] However, because the emission of organic exhaust gas is not stable over a long period and its output pressure is uncertain, while the compressor must always be running, insufficient exhaust gas emission (low load condition) can easily lead to frost formation and damage to the heat exchanger and refrigeration system. CN221802220U discloses a VOC deep-cooling device that, when exhaust gas is insufficient, mixes a portion of the refrigerant output from the compressor with the refrigerant output from the expansion valve via a pressure regulating valve and sends it into the heat exchanger, preventing excessively low temperatures within the heat exchanger. However, this device regulates the heat exchanger temperature by adjusting the refrigerant temperature. Since the compressor operates continuously, the oil always needs to be cooled before returning to the compressor to lower its temperature. This results in the oil cooler continuing to operate under low load conditions, wasting energy. If the oil separated by the oil separator returns directly to the compressor, the high oil temperature can prevent the compressor from functioning properly. Utility Model Content

[0004] The technical problem to be solved by this utility model is to overcome the shortcomings of the prior art and provide a dual-condition semi-falling film low-temperature refrigeration unit, in which the oil cooler can work intermittently when working under low load, thus saving energy.

[0005] The technical solution adopted by this utility model to solve its technical problem is as follows: The dual-condition semi-falling film low-temperature refrigeration unit includes a compressor, an oil separator, a condenser, an expansion valve and a semi-falling film heat exchanger connected in sequence. An oil cooler is provided between the oil separator and the compressor. The oil separator is also connected to the semi-falling film heat exchanger. The semi-falling film heat exchanger includes a heat exchanger shell and heat exchanger tubes arranged in the heat exchanger shell. The upper part of the heat exchanger shell is a falling film heat exchange zone and the lower part is a bath heat exchange zone. The lower part of the heat exchanger shell is connected to the refrigerant inlet of the compressor. The upper part of the heat exchanger shell is provided with a falling film refrigerant nozzle for spraying refrigerant into the heat exchanger tubes in the falling film heat exchange zone.

[0006] The bath-type heat exchange zone is also equipped with oil heat exchange tubes. One end of the oil heat exchange tube is connected to the oil outlet of the oil separator, and the other end supplies oil to the compressor. The oil heat exchange tubes directly exchange heat with the refrigerant in the bath-type heat exchange zone. Under low-load conditions, the oil cooler does not need to work continuously, thus extending the service life of the oil cooler.

[0007] Preferably, the other end of the oil heat exchanger tube is connected to the compressor via an auxiliary oil supply line, and an oil supply solenoid valve is provided on the auxiliary oil supply line.

[0008] Preferably, the other end of the oil heat exchange tube is connected to the inlet of the oil cooler via an auxiliary oil supply pipeline.

[0009] Preferably, the heat exchanger shell is provided with multiple bath heat exchange zones arranged sequentially from top to bottom, each bath heat exchange zone is provided with a refrigerant baffle, adjacent bath heat exchange zones are connected by a refrigerant overflow pipe, and the oil heat exchange pipe is located in the uppermost bath heat exchange zone.

[0010] Preferably, the bath heat exchange zone includes a first bath heat exchange zone, a second bath heat exchange zone, and a third bath heat exchange zone arranged sequentially from top to bottom, with the third bath heat exchange zone connected to the condenser.

[0011] Preferably, the oil heat exchange tube is a coil, and the oil heat exchange tube is fitted to the inner wall of the heat exchanger shell.

[0012] Preferably, the condenser includes a first condenser and a second condenser arranged in parallel. Both the first condenser and the second condenser are provided with refrigerant cooling pipes. The refrigerant outlet of the oil separator is connected to the refrigerant cooling pipe inlets of the first condenser and the second condenser, respectively. The semi-falling film heat exchanger is connected to the refrigerant cooling pipe outlets of the first condenser and the second condenser, respectively.

[0013] Preferably, the first condenser and the second condenser are arranged side by side and fixed above the compressor. A liquid storage tank is also provided on one side of the compressor, and the liquid storage tank is connected to a semi-falling film heat exchanger.

[0014] Compared with existing technologies, the beneficial effects of the above-mentioned technical solution of the dual-condition semi-falling film cryogenic refrigeration unit are as follows:

[0015] Under low-load conditions, the volume of gas to be processed is small, and the temperature of the liquid refrigerant in the semi-falling film heat exchanger is still low. The low-temperature refrigerant in the bath heat exchange zone is used to directly cool the oil, and the cooled oil is returned to the compressor. This allows the oil cooler to work intermittently, reducing energy consumption and extending the service life of the oil cooler. Attached Figure Description

[0016] Figure 1 This is a three-dimensional structural diagram of Example 1 of the dual-condition semi-falling film cryogenic refrigeration unit.

[0017] Figure 2 This is a schematic diagram of the dual-condition semi-falling film cryogenic refrigeration unit in Example 1.

[0018] Figure 3 This is a schematic diagram of the semi-falling film heat exchanger in Example 1.

[0019] Figure 4 This is a schematic diagram of the dual-condition semi-falling film cryogenic refrigeration unit in Example 2.

[0020] The components are as follows: 1. Frame; 2. Compressor; 3. Oil separator; 4. First condenser; 5. Second condenser; 6. Semi-falling film heat exchanger; 7. Gas-liquid separator; 8. Pre-heat exchanger; 9. Oil cooler; 10. Liquid storage tank; 11. Oil heat exchange tube; 12. Auxiliary oil supply pipeline; 13. Oil supply solenoid valve; 601. Heat exchanger shell; 602. Heat exchanger tube; 603. Falling film heat exchange zone; 604. First bath heat exchange zone; 605. Second bath heat exchange zone; 606. Third bath heat exchange zone; 607. Baffle; 608. Refrigerant overflow pipe. Detailed Implementation

[0021] Figures 1-3 This is the optimal embodiment of the dual-condition semi-falling film cryogenic refrigeration unit, as detailed below in conjunction with the attached diagram. Figures 1-4 The present invention will be further described below.

[0022] Example 1

[0023] Reference Figure 1-2This dual-condition semi-falling film cryogenic refrigeration unit includes a compressor 2, an oil separator 3, a condenser, an expansion valve, and a semi-falling film heat exchanger 6 connected in sequence. An oil cooler 9 is installed between the oil separator 3 and the compressor 2. The oil separator 3 is also connected to the semi-falling film heat exchanger 6. An oil heat exchange tube 11 is installed inside the semi-falling film heat exchanger 6. One end of the oil heat exchange tube 11 is connected to the oil outlet of the oil separator 3, and the other end supplies oil to the compressor 2. Under low-load conditions, the oil heat exchange tube 11 can directly exchange heat with the refrigerant in the semi-falling film heat exchanger 6 to cool it down, and then directly send the low-temperature oil into the compressor 2 without having to be cooled by the oil cooler 9 before returning to the compressor 2.

[0024] The present invention will be further described below with reference to specific embodiments. However, those skilled in the art should understand that the detailed description given here with reference to the accompanying drawings is for better explanation. The structure of the present invention may exceed the limited embodiments described herein. Some equivalent alternatives or common means will not be described in detail here, but they still fall within the protection scope of this application.

[0025] The compressor 2 is fixed to the lower middle part of the frame 1. A preheater 8 is also provided on one side of the semi-falling film heat exchanger 6. The lower end of the preheater 8 is the exhaust gas inlet, and the exhaust gas outlet at the upper end of the preheater 8 is connected to the upper part of the semi-falling film heat exchanger 6. The refrigerant that has been heat-exchanged in the semi-falling film heat exchanger 6 enters the preheater 8 to pre-cool the exhaust gas. Then the refrigerant returns to the compressor 2 to further improve the refrigeration efficiency.

[0026] The condenser includes a first condenser 4 and a second condenser 5 connected in parallel. The first condenser 4 and the second condenser 5 are mounted side-by-side on a frame 1 above the compressor 2. Both the first condenser 4 and the second condenser 5 are equipped with refrigerant cooling pipes. The refrigerant outlet of the oil separator 3 is connected to the inlets of the refrigerant cooling pipes of the first condenser 4 and the second condenser 5, respectively. The semi-falling film heat exchanger 6 is connected to the outlets of the refrigerant cooling pipes of the first condenser 4 and the second condenser 5, respectively. Under low-load conditions, only one of the first condenser 4 or the second condenser 5 can operate, further reducing energy consumption.

[0027] A liquid storage tank 10 is also provided on one side of the compressor 2. The liquid storage tank 10 is connected to the semi-falling film heat exchanger 6. The liquid generated by the condensation of the exhaust gas in the semi-falling film heat exchanger 6 is stored in the liquid storage tank 10. The semi-falling film heat exchanger 6 is fixed on the other side of the compressor 2, and the oil cooler 9 is fixed on the upper side of the compressor 2.

[0028] See Figure 3The semi-falling film heat exchanger 6 in this embodiment includes a heat exchanger housing 601 and heat exchanger tubes 602 disposed in the heat exchanger housing 601. The upper part of the heat exchanger housing 601 is a falling film heat exchange zone 603, and the lower part is a bath heat exchange zone. The lower part of the heat exchanger housing 601 is connected to the refrigerant inlet of the compressor 2, and the upper part of the heat exchanger housing 601 is provided with a falling film refrigerant nozzle for spraying refrigerant into the heat exchanger tubes in the falling film heat exchange zone 603.

[0029] In this embodiment, a first bath heat exchange zone 604, a second bath heat exchange zone 605, and a third bath heat exchange zone 606 are arranged sequentially from top to bottom inside the heat exchanger housing 601. A refrigerant baffle 607 is provided between each bath heat exchange zone, and adjacent bath heat exchange zones are connected by a refrigerant overflow pipe 608. The third bath heat exchange zone 606 is connected to the condenser, and the oil heat exchange pipe 11 is arranged in the first bath heat exchange zone 604.

[0030] The other end of the oil heat exchanger tube 11 is connected to the compressor 2 via an auxiliary oil supply line 12, and an oil supply solenoid valve 13 is provided on the auxiliary oil supply line 12. In this embodiment, the oil heat exchanger tube 11 is a coil, and the oil heat exchanger tube 11 is fitted to the inner wall of the heat exchanger shell 601. Under low load conditions, the temperature of the semi-falling film heat exchanger 6 is low, and some of the cold energy is absorbed by the oil heat exchanger tube 11, which can prevent frost from forming on the outer wall of the heat exchanger shell 601.

[0031] Working process: Compressor 2 compresses the refrigerant, which becomes a high-temperature, high-pressure gaseous state. This gaseous refrigerant undergoes oil-gas separation in oil separator 3 before entering the first condenser 4 and the second condenser 5. The high-temperature, high-pressure gaseous refrigerant is condensed in the first condenser 4 and the second condenser 5 into a medium-temperature, high-pressure liquid refrigerant. This medium-temperature, high-pressure liquid refrigerant then passes through an expansion valve and becomes a low-temperature liquid refrigerant. Part of this low-temperature liquid refrigerant is sprayed into the falling film heat exchange zone 603, forming a film on the outer wall of the heat exchange tubes 602, cooling the material inside the heat exchange tubes 602. The other part of the refrigerant is sent to the third bath heat exchange zone 606 and gradually flows upwards along the refrigerant overflow pipe 608 into the second bath heat exchange zone 605 and the first bath heat exchange zone 604. The material is cooled, with part condensing into a liquid and being sent to the liquid storage tank 10, while the other part of the gaseous material is sent to the next processing stage. After heat exchange, the refrigerant becomes gaseous. After passing through the gas-liquid separator 7, the gaseous refrigerant returns to the compressor 2 and is compressed again, forming a refrigerant cycle.

[0032] Under full load conditions, the oil after oil-gas separation by oil separator 3 is cooled by oil cooler 9 and then returns to compressor 2. When low load conditions occur, oil supply solenoid valve 13 opens, and the oil after oil-gas separation by oil separator 3 enters oil heat exchange tube 11. After exchanging heat with the refrigerant in the first bath heat exchange zone 604 and cooling down, it directly enters compressor 2 under pressure difference or pumping. The oil cooler 9 no longer needs to work continuously, which allows the oil cooler 9 to work intermittently, reducing energy consumption and increasing the service life of the oil cooler 9.

[0033] Example 2

[0034] See Figure 4 In this embodiment, the other end of the oil heat exchanger tube 11 is directly connected to the oil inlet of the compressor 2 via an auxiliary oil supply line 12, and an oil supply solenoid valve 13 is provided on the auxiliary oil supply line 12. When a low-load condition occurs, the oil supply solenoid valve 13 opens, and the oil after oil-gas separation by the oil separator 3 enters the oil heat exchanger tube 11. After exchanging heat with the refrigerant in the first bath heat exchange zone 604 and cooling down, it is sent to the oil cooler 9, and then enters the compressor 2 through the oil cooler 9 under pressure difference or pumping. Since the oil already has a low temperature at this time, the oil cooler 9 does not need to work continuously. This allows the oil cooler 9 to work intermittently, reducing energy consumption and improving the service life of the oil cooler 9.

[0035] The above description is merely a preferred embodiment of this utility model and is not intended to limit the utility model in any other way. Any person skilled in the art may make changes or modifications to the above-disclosed technical content to create equivalent embodiments. However, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of this utility model without departing from its technical solution shall still fall within the protection scope of this utility model.

Claims

1. A dual-condition semi-falling film cryogenic refrigeration unit, comprising a compressor (2), an oil separator (3), a condenser, an expansion valve, and a semi-falling film heat exchanger (6) connected in sequence, wherein an oil cooler (9) is provided between the oil separator (3) and the compressor (2), and the oil separator (3) is also connected to the semi-falling film heat exchanger (6), characterized in that: The semi-falling film heat exchanger (6) includes a heat exchanger shell (601) and heat exchanger tubes (602) disposed in the heat exchanger shell (601). The upper part of the heat exchanger shell (601) is a falling film heat exchange zone (603), and the lower part is a bath heat exchange zone. The lower part of the heat exchanger shell (601) is connected to the refrigerant inlet of the compressor (2). The upper part of the heat exchanger shell (601) is provided with a falling film refrigerant nozzle for spraying refrigerant into the heat exchange tubes in the falling film heat exchange zone (603). The bath heat exchange zone is also equipped with an oil heat exchange tube (11). One end of the oil heat exchange tube (11) is connected to the oil outlet of the oil separator (3), and the other end supplies oil to the compressor (2).

2. The dual-condition semi-falling film cryogenic refrigeration unit according to claim 1, characterized in that: The other end of the oil heat exchange tube (11) is connected to the compressor (2) through an auxiliary oil supply line (12), and an oil supply solenoid valve (13) is provided on the auxiliary oil supply line (12).

3. The dual-condition semi-falling film cryogenic refrigeration unit according to claim 1, characterized in that: The other end of the oil heat exchange tube (11) is connected to the inlet of the oil cooler (9) via an auxiliary oil supply line (12).

4. The dual-condition semi-falling film cryogenic refrigeration unit according to claim 1, characterized in that: The heat exchanger shell (601) is provided with multiple bath heat exchange zones arranged sequentially from top to bottom. Each bath heat exchange zone is provided with a refrigerant baffle (607). Adjacent bath heat exchange zones are connected by a refrigerant overflow pipe (608). The oil heat exchange pipe (11) is located in the uppermost bath heat exchange zone.

5. The dual-condition semi-falling film cryogenic refrigeration unit according to claim 4, characterized in that: The bath heat exchange zone includes a first bath heat exchange zone (604), a second bath heat exchange zone (605) and a third bath heat exchange zone (606) arranged sequentially from top to bottom, with the third bath heat exchange zone (606) connected to the condenser.

6. The dual-condition semi-falling film cryogenic refrigeration unit according to claim 1 or 4, characterized in that: The oil heat exchange tube (11) is a coil, and the oil heat exchange tube (11) is fitted to the inner wall of the heat exchanger shell (601).

7. The dual-condition semi-falling film cryogenic refrigeration unit according to claim 1, characterized in that: The condenser includes a first condenser (4) and a second condenser (5) arranged in parallel. Both the first condenser (4) and the second condenser (5) are equipped with refrigerant cooling pipes. The refrigerant outlet of the oil separator (3) is connected to the inlet of the refrigerant cooling pipe of the first condenser (4) and the second condenser (5) respectively. The semi-falling film heat exchanger (6) is connected to the outlet of the refrigerant cooling pipe of the first condenser (4) and the second condenser (5) respectively.

8. The dual-condition semi-falling film cryogenic refrigeration unit according to claim 7, characterized in that: The first condenser (4) and the second condenser (5) are arranged side by side. The first condenser (4) and the second condenser (5) are fixed above the compressor (2). A liquid storage tank (10) is also provided on one side of the compressor (2). The liquid storage tank (10) is connected to the semi-falling film heat exchanger (6).

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