Novel refrigerating machine oil recovery system

Abstract

A novel refrigerating machine oil recovery system comprises a refrigeration compressor and a horizontal oil separator which are combined together, an air outlet of the horizontal oil separator is sequentially connected with a condenser, an ammonia circulation tank, an evaporator and an ammonia separator through pipelines, and a refrigerant outlet of the ammonia separator is connected with an air inlet of the refrigeration compressor through a pipeline; an oil cooler and a secondary oil separator are arranged between the horizontal oil separator and the condenser; an oil recovery pipe is arranged between the secondary oil separator and an air inlet of the refrigeration compressor, one end of the oil recovery pipe is connected with an oil drain valve of the secondary oil separator, and the other end of the oil recovery pipe is connected with the air inlet of the refrigeration compressor; pressure difference exists between the inlet and the outlet of the two ends of the oil recovery pipe. The device has the advantages of energy conservation, consumption reduction and yield increase.

Description

Technical Field

[0001] The utility model relates to the technical field of refrigeration systems, in particular to a novel refrigeration oil recovery system. Background Art

[0002] As the most basic unit of chemical industry, the refrigeration system is of self-evident importance in chemical production. The continuous, safe and stable operation of the refrigeration compressor, which is the heart of the refrigeration system, is very critical and related to the normal and economical operation of the refrigeration system.

[0003] The single-stage vapor compression refrigeration system consists of four basic components: refrigeration compressor, condenser, evaporator and throttle valve. They are connected in sequence by pipes to form a closed system. The refrigerant circulates continuously in the system, changes state and exchanges heat with the outside world. Its working process is as follows Figure 4 As shown. Liquid refrigerant (ammonia, Freon, etc.) absorbs the heat of the material being cooled in the evaporator and then vaporizes into low-temperature and low-pressure steam. It is sucked in by the compressor, compressed into high-pressure, high-temperature superheated steam, and then discharged into the condenser. In the condenser, it releases heat to the cooling medium (water or air) and condenses into high-pressure liquid. It is throttled by the throttle valve to become a low-pressure and low-temperature refrigerant, and enters the evaporator again to absorb heat and vaporize to achieve the purpose of circulating refrigeration. In this way, the refrigerant completes a refrigeration cycle through four basic processes in the system: evaporation, compression, condensation, and throttling. In the refrigeration system, the evaporator, condenser, compressor, and throttle valve are the four essential parts of the refrigeration system. Among them, the evaporator is a device that exchanges cold with the material, and the refrigerant absorbs the heat of the cooled object in it to achieve the refrigeration of the material. The compressor is the heart, which plays the role of inhaling, compressing, and transporting refrigerant vapor. The condenser is a device that releases heat, and transfers the heat absorbed in the evaporator together with the heat converted by the compressor work to the cooling medium.

[0004] As a running equipment, the lubrication of the refrigerator is extremely important. Now the new compressor has its own oil separator and also serves as an oil storage tank. The oil pipe is led out from the bottom of the oil separator and enters the compressor air inlet, and is sprayed into the unit together with the refrigerant gas to lubricate the compressor and effectively reduce the noise of the compressor; the refrigerator oil and the refrigerant are compressed together and enter the oil separator at the bottom of the unit for the initial separation of the refrigerant and the oil. There are three levels of separation in the oil separator, namely collision inertia separation, gravity sedimentation separation and polymer filter element separation. Among them, the separation with the highest separation efficiency is the polymer filter element separation. After being compressed by the compressor, the superheated refrigerant gas decreases in volume, and its pressure and temperature both increase. The polymer material of the filter element is subjected to thermal condensation under high temperature conditions for a long time, causing larger and larger pores in the middle of the filter element. The oil mist and refrigerant gas that are not effectively intercepted pass through the pores and enter the condenser and refrigerant storage tank behind, and are then sent from the refrigerant storage tank to the evaporator and then back to the compressor. As a result, the refrigeration oil is spread throughout the entire refrigeration system along with the refrigerant. Due to the poor thermal conductivity of the refrigeration oil, the oil film on the wall of the heat exchange tube of the condenser increases the heat exchange resistance, and cannot effectively reduce the temperature of the gas refrigerant and condense it into liquid, so the condenser is forced to be added; after the liquid refrigerant in the refrigerant storage tank mixes with the oil and enters the evaporator, a layer of oil film will also be evenly distributed on the heat exchange tube of the evaporator, making it impossible for the refrigerant and the frozen material to exchange heat efficiently, so the evaporator is forced to be added. Therefore, the additional condensers and evaporators need to be equipped with matching pumps, which increases power consumption; the oil entering the refrigeration system cannot be effectively utilized. After oil separation, it is discharged into the oil boiler to evaporate ammonia and then discharged into the waste oil pool, which also causes a great waste of refrigeration oil; in many factories, because the system equipment is matched with the production capacity, there are no extra evaporators and condensers to add, and they are forced to reduce production. In a chemical plant, in the process of using ammonia as a refrigerant, because the horizontal oil separator filter element of the ice machine is frequently damaged, a total of 16,320 kg of new refrigeration oil needs to be added per year, 36 filter elements need to be replaced per year, and 20,340 kg of refrigeration oil discharged into the waste oil pool (including wastewater) needs to be processed. The refrigeration system has been running with problems for a long time, and the exhaust pressure of the refrigeration compressor has been greater than 1.5 MPa for a long time, and it is frequently damaged. The annual maintenance cost reaches 338,700 yuan.

[0005] In the utility model patent with authorization announcement number CN206683287U, a refrigeration oil recovery system is disclosed, including a condensing device, a separating device, a filtering device and a recovering device, the condensing device is provided with a first air inlet pipe, a first air outlet pipe and a first oil outlet, the separating device is provided with a second air inlet pipe, a second air outlet pipe and a first oil outlet, the filtering device is provided with a third air inlet pipe, a third air outlet pipe and a third oil outlet, the first air inlet pipe is used to be connected to the exhaust port of the refrigeration system, the first air outlet pipe is connected to the second air inlet pipe, the second air outlet pipe is connected to the third air inlet pipe, the first oil outlet, the second oil outlet and the third oil outlet are respectively connected to the recovering device, the third air outlet pipe is used to be connected to the condenser of the refrigeration system, and the condensing device is used to condense the refrigeration oil discharged from the refrigeration system. After three times of gas and oil separation, the refrigeration oil can be completely separated to the recovery device, which effectively improves the recovery rate of the refrigeration oil. This patent adopts the method of using an oil pump to extract and recover the refrigeration oil to the oil storage tank or the compressor inlet. This increases the inconvenience of operation, increases the labor intensity of workers, fails to achieve dynamic balance of the refrigeration oil, wastes the pressure difference between the compressor exhaust port and the air inlet, and increases unnecessary power consumption. Utility Model Content

[0006] The utility model aims to overcome the deficiencies of the prior art and provide a novel refrigeration oil recovery system, which improves the separation and recovery of refrigeration oil in refrigeration exhaust gas, thereby achieving the effects of energy saving, consumption reduction and increased production.

[0007] The purpose of this utility model is achieved through the following technical solutions:

[0008] A novel refrigeration oil recovery system comprises a refrigeration compressor and a horizontal oil separator combined together, wherein the air outlet of the horizontal oil separator is connected to a condenser 7, an ammonia circulation tank, an evaporator and an ammonia separator in sequence through a pipeline, and the refrigerant outlet of the ammonia separator is connected to the air inlet of the refrigeration compressor through a pipeline;

[0009] An oil cooler and a secondary oil separator are provided between the horizontal oil separator and the condenser 7; an oil recovery pipe is provided between the secondary oil separator and the air inlet of the refrigeration compressor, one end of the oil recovery pipe is connected to the oil drain valve of the secondary oil separator, and the other end of the oil recovery pipe is connected to the air inlet of the refrigeration compressor;

[0010] There is a pressure difference between the inlet and outlet at both ends of the oil recovery pipe.

[0011] In one or more embodiments of the present invention, the pressure difference between the inlet and outlet at both ends of the oil recovery pipe is 0.6 MPa~1.2 MPa.

[0012] In one or more embodiments of the utility model, the oil cooler includes a shell arranged horizontally, in which heat exchange tubes are installed through a plurality of baffles, a notch is left between one end of the baffle and the shell, and adjacent notches are staggered up and down; a temperature difference compensator with an outward annular protrusion is provided in the middle of the shell; a first air inlet, an air outlet, a safety valve interface and a cooling water outlet are also provided on the upper side of the shell; a drain port, a first air outlet, a sewage outlet, a cooling water inlet and a support are also provided on the lower side of the shell; the air outlet of the oil cooler is connected to the air inlet of the secondary oil separator through a first pipe.

[0013] In one or more embodiments of the present invention, the air inlet of the oil cooler is connected to the air outlet of the horizontal oil separator through a second pipeline.

[0014] In one or more embodiments of the utility model, the secondary oil separator includes a vertically arranged cylinder, on which a number of polymer filter cartridges are vertically installed, and the outer wall of the cylinder is also provided with an air inlet, an oil drain valve, a liquid level gauge, a second air outlet, an inspection hole, a safety valve and a glass sight glass; the polymer filter cartridge and the air outlet are located on the upper side of the second air inlet, and a collision baffle is also fixed to the inner end of the air inlet; the air outlet of the secondary oil separator is connected to the condenser through a pipe.

[0015] In one or more embodiments of the utility model, the oil drain valve is also connected to the oil boiler through a third pipe, and the third pipe is connected to the oil recovery pipe; the bottom of the condenser, ammonia circulation tank and evaporator are connected to the oil boiler through a pipe for regularly discharging the refrigeration oil remaining at the bottom of each.

[0016] Beneficial effects of the utility model:

[0017] 1. Commonly used oil filter element fibers are mostly chemical fibers such as polyester, and their long-term use temperature is generally 60~70℃. If they are used for a long time at a temperature higher than this range, the chemical fibers will shrink and deform, resulting in large or small holes in the part where the chemical fibers and the filter element housing are connected. The high-temperature gas of 70~110℃ discharged by the refrigeration compressor will carry oil mist and oil vapor through these holes and enter the subsequent heat exchanger; therefore, the gas discharged from the refrigeration compressor passes through the refrigeration unit's own horizontal oil separator for simple sedimentation and separation, and then enters the oil cooler to drop below 60℃, protecting the chemical fibers in the subsequent secondary oil separator, preventing high-temperature shrinkage and deformation, and extending the service life of its filter element;

[0018] 2. Normal refrigeration oil has a boiling point of 150℃~170℃ and a bubble point of about 100℃. However, after long-term use in the unit, the long carbon chain of the refrigeration oil is mechanically sheared to a certain extent and becomes a short carbon chain. The boiling point of the short carbon chain will be much lower than 100℃. Therefore, lowering the exhaust temperature of the refrigeration compressor will help the gaseous refrigeration oil condense into liquid droplets, which can be intercepted by the secondary oil separator for reuse, thereby improving the recovery rate of the refrigeration oil.

[0019] 3. The reduction of exhaust temperature also reduces the gas volume. When the flow area remains unchanged, it is also related to reducing the gas flow rate, which will help the subsequent separation of oil and gas;

[0020] 4. By using the pressure difference between the compressor exhaust port and the air inlet to return oil to the refrigeration compressor, power consumption is reduced;

[0021] 5. Through the method of oil cooling + secondary oil separation + automatic oil return, the efficient recovery of refrigeration oil is improved, and recycling is achieved, saving a large amount of refrigeration oil purchase costs, while reducing waste oil emissions and reducing the pressure of waste oil treatment procedures; because the introduction of refrigeration oil into the refrigeration system is greatly reduced, the energy consumption of the condenser and evaporator is greatly reduced, the production capacity of the equipment has been improved, and greater economic benefits have been achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a structural flow chart of the utility model;

[0023] Figure 2 It is a schematic diagram of the structure of the oil cooler;

[0024] Figure 3 It is a structural schematic diagram of the secondary oil separator;

[0025] Figure 4 It is a structural flow chart of a conventional refrigeration system. DETAILED DESCRIPTION

[0026] In order to make the purpose, technical scheme and advantages of the embodiment of the utility model clearer, the technical scheme in the embodiment of the utility model will be clearly and completely described below in conjunction with the drawings in the embodiment of the utility model. Obviously, the described embodiment is a part of the embodiment of the utility model, not all of the embodiments. The components of the embodiment of the utility model generally described and shown in the drawings here can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiment of the utility model provided in the drawings is not intended to limit the scope of the utility model claimed for protection, but merely represents the selected embodiment of the utility model. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without making creative work belong to the scope of protection of the utility model.

[0027] Embodiment 1: In this embodiment, Figures 1 to 3 As shown, a novel refrigeration oil recovery system comprises a refrigeration compressor 1 and a horizontal oil separator 2 which are combined together, wherein the air outlet of the horizontal oil separator 2 is sequentially connected to a condenser 7, an ammonia circulation tank 5, an evaporator 8 and an ammonia separator 9 through a pipeline, and the refrigerant outlet of the ammonia separator 9 is connected to the air inlet of the refrigeration compressor 1 through a pipeline;

[0028] An oil cooler 3 and a secondary oil separator 4 are provided between the horizontal oil separator 2 and the condenser 7; an oil recovery pipe 10 is provided between the secondary oil separator 4 and the air inlet of the refrigeration compressor 1, one end of the oil recovery pipe 10 is connected to the oil drain valve 13 of the secondary oil separator 4, and the other end of the oil recovery pipe 10 is connected to the air inlet of the refrigeration compressor 1;

[0029] There is a pressure difference between the inlet and outlet at both ends of the oil recovery pipe 10 .

[0030] In this embodiment, by adding an oil cooler 3 and a secondary oil separator 4 to the original system, after the system runs smoothly, first slowly open the valve on the cooling water outlet 35, and then open the valve on the cooling water inlet 34. When opening the valve, open it once, and slowly fill the oil cooler 3 with water. At the same time, observe the outlet gas temperature of the oil cooler 3, adjust the cooling water volume, keep the outlet gas temperature higher than the refrigerant condensation temperature corresponding to the outlet gas pressure by 3-10°C (generally controlled temperature is 45-60°C), and prevent gaseous ammonia from condensing into liquid ammonia. If too much liquid ammonia enters the oil separator and then returns to the compressor, it will cause liquid hammer in the compressor and damage the compressor; but the outlet temperature of the oil cooler should not be controlled too high. Too high a temperature will make some small molecules with short carbon chains in the condensing oil unable to be completely condensed into liquid. The gaseous refrigeration oil passes through the secondary oil separator with the gaseous refrigerant and enters the subsequent equipment, which reduces the recovery rate of the refrigeration oil. At the same time, too high ammonia temperature will cause the polymer filter element in the secondary oil separator to shrink and fail.

[0031] The refrigeration oil cooled into liquid state is intercepted in the secondary oil separator 4 and temporarily stored in the lower part of the secondary oil separator 4. When the secondary oil liquid level rises to 1 / 3, the drain valve 13 at the lower part of the secondary oil separator 4 and the valve on the oil recovery pipe 10 are opened, and the pressure difference (0.6MPa~1.2MPa) between the exhaust port and the air inlet of the compressor is used to return oil to the refrigeration compressor. The drain valve 13 and the valve on the oil recovery pipe 10 automatically adjust the opening according to the oil level in the secondary oil separator 4 to keep the refrigeration oil automatically circulated.

[0032] In one or more embodiments of the present invention, the pressure difference between the inlet and outlet at both ends of the oil recovery pipe 10 is 0.6 MPa-1.2 MPa.

[0033] In one or more embodiments of the utility model, the oil cooler 3 includes a shell 24 arranged horizontally, and a heat exchange tube 23 is installed in the shell 24 through a plurality of baffles 25, and a gap is left between one end of the baffle 25 and the shell 24, and the adjacent gaps are staggered up and down; the middle part of the shell 24 has a temperature difference compensator 26 that protrudes outward in an annular shape; the upper side of the shell 24 is also provided with a first air inlet 22, an air outlet 29, a safety valve interface 27 and a cooling water outlet 35; the lower side of the shell 24 is also provided with a drain port 30, a first air outlet 31, a sewage outlet 33, a cooling water inlet 34 and a support 32; the air outlet of the oil cooler 3 is connected to the air inlet of the secondary oil separator 4 through a first pipeline.

[0034] In this embodiment, the heat exchange tube 23 of the oil cooler 3 adopts a straight tube or a corrugated tube, wherein cooling water flows through the tube side and refrigerant flows through the shell 24. When the equipment is installed, the refrigerant inlet maintains an inclination of 1-3% toward the outlet direction, and a small gap is left between the lower part of the baffle 25 and the shell to ensure that the condensed refrigeration oil flows smoothly to the outlet; at the same time, the shell 23 adopts a temperature difference compensator to prevent the heat exchange tube weld from being torn due to the large temperature difference between the shell side and the tube side and the inconsistent expansion length of the shell and the tube side.

[0035] In one or more embodiments of the present invention, the first air inlet 22 of the oil cooler 3 is connected to the air outlet of the horizontal oil separator 2 via a second pipeline.

[0036] In one or more embodiments of the utility model, the secondary oil separator 4 includes a vertically arranged cylinder 19, on which a plurality of polymer filter cartridges 15 are vertically installed, and the outer wall of the cylinder 19 is also provided with a second air inlet 11, an oil drain valve 13, a liquid level gauge 14, a second air outlet 16, an inspection hole 17, a safety valve 18 and a glass sight glass 20; the polymer filter cartridge 15 and the second air outlet 16 are located on the upper side of the second air inlet 11, and a collision baffle 12 is also fixed to the inner end of the second air inlet 11; the second air outlet 16 of the secondary oil separator 4 is connected to the condenser 7 through a pipe.

[0037] In this embodiment, the secondary oil separator adopts a combination of three gas-liquid separation methods to effectively improve the separation efficiency of the oil separator: a collision baffle 12 is set at the inlet of the secondary oil separator, and when the gaseous refrigerant entrains oil mist and collides with the collision baffle 12 at a high speed, a collision occurs, so that the refrigeration oil dispersed in the gas in a mist form agglomerates into larger oil droplets and adheres to the collision baffle 12, and the gas with lower viscosity turns to quickly leave the collision baffle 12, so as to achieve the effect of oil-gas separation, that is, collision separation; after the gas entrained with a small amount of oil mist leaves the collision baffle 12 and enters the cylinder 19, because the cylinder 19 is enlarged, the gas speed is reduced from 20m / s to 0.3m / s, and the sudden reduction in speed utilizes the density difference between oil and gas and the principle of different gravitational forces under the same conditions for separation, that is, sedimentation separation; the gas after sedimentation separation still entrains a very small amount of oil mist, which is intercepted by the polymer filter cartridge 15 and gathered inside the filter cartridge to form larger oil droplets, and oil-gas separation is performed again, that is, filtration separation, which is also the most efficient and precise gas-liquid separation method.

[0038] In one or more embodiments of the utility model, the oil drain valve 13 is also connected to the oil boiler 6 through a third pipe, and the third pipe is connected to the oil recovery pipe 10; the bottom of the condenser 7, the ammonia circulation tank 5 and the evaporator 8 are connected to the oil boiler through a pipe for regularly discharging the refrigeration oil remaining at the bottom of each.

[0039] The refrigeration oil remaining in the bottom of the secondary oil separator 4, evaporator 8, condenser 7 and ammonia circulation tank 5 is regularly discharged to the oil boiler to prevent the refrigeration oil from being retained in the refrigeration system for a long time and affecting the heat exchange efficiency.

[0040] According to statistics from a chemical plant one year after the above-mentioned technical transformation, compared with before the transformation, less equipment was used to save electricity, less refrigeration oil, oil filter purchase costs, refrigeration system maintenance costs and other direct costs were 1.2719 million yuan per year, as shown in the following table:

[0041]

[0042] In the description of the present utility model, it should be noted that the terms "upper", "lower", "inner", "outer", "left", "right" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship in which the utility model product is usually placed when in use, or the orientation or positional relationship commonly understood by those skilled in the art, which is only for the convenience of describing the present utility model and simplifying the description, rather than indicating or implying that the equipment or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation of the present utility model. In addition, the terms "first", "second" and the like are only used to distinguish the description, and cannot be understood as indicating or implying relative importance. In the description of the present utility model, it should also be noted that, unless otherwise clearly specified and limited, the terms "set", "connection" and the like should be understood in a broad sense, for example, "connection" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be the internal connection of two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present utility model can be understood according to the specific circumstances.

Claims

1. A novel refrigeration oil recovery system, comprising a refrigeration compressor (1) and a horizontal oil separator (2) combined together, wherein the air outlet of the horizontal oil separator (2) is connected to a condenser (7), an ammonia circulation tank (5), an evaporator (8) and an ammonia separator (9) in sequence through a pipeline, and the refrigerant outlet of the ammonia separator (9) is connected to the air inlet of the refrigeration compressor (1) through a pipeline; characterized in that: An oil cooler (3) and a secondary oil separator (4) are provided between the horizontal oil separator (2) and the condenser (7); an oil recovery pipe (10) is provided between the secondary oil separator (4) and the air inlet of the refrigeration compressor (1); one end of the oil recovery pipe (10) is connected to an oil drain valve (13) of the secondary oil separator (4), and the other end of the oil recovery pipe (10) is connected to the air inlet of the refrigeration compressor (1); There is a pressure difference between the inlet and outlet at both ends of the oil recovery pipe (10).

2. A novel refrigeration oil recovery system according to claim 1, characterized in that: The pressure difference between the inlet and outlet at both ends of the oil recovery pipe (10) is 0.6 MPa-1.2 MPa.

3. A novel refrigeration oil recovery system according to claim 1, characterized in that: The oil cooler (3) comprises a shell (24) arranged transversely, a heat exchange tube (23) being installed in the shell (24) via a plurality of baffles (25), a notch being left between one end of the baffle (25) and the shell (24), and adjacent notches being arranged in an up-and-down staggered manner; a temperature difference compensator (26) protruding outward in an annular shape is provided in the middle of the shell (24); a first air inlet (22), an air outlet (29), a safety valve interface (27) and a cooling water outlet (35) are also provided on the upper side of the shell (24); a drain port (30), a first air outlet (31), a sewage outlet (33), a cooling water inlet (34) and a support (32) are also provided on the lower side of the shell (24); the air outlet of the oil cooler (3) is connected to the air inlet of the secondary oil separator (4) via a first pipeline.

4. A novel refrigeration oil recovery system according to claim 3, characterized in that: The air inlet (22) of the oil cooler (3) is connected to the air outlet of the horizontal oil separator (2) via a second pipeline.

5. A novel refrigeration oil recovery system according to claim 1, characterized in that: The secondary oil separator (4) comprises a vertically arranged cylinder (19), on which a plurality of polymer filter cartridges (15) are vertically mounted, and the outer wall of the cylinder (19) is also provided with a second air inlet (11), an oil drain valve (13), a liquid level gauge (14), a second air outlet (16), a maintenance hole (17), a safety valve (18) and a glass sight glass (20); the polymer filter cartridge (15) and the air outlet (16) are located on the upper side of the second air inlet (11), and a collision baffle (12) is also fixed to the inner end of the second air inlet (11); the second air outlet (16) of the secondary oil separator (4) is connected to a condenser (7) via a pipeline.

6. A novel refrigeration oil recovery system according to claim 5, characterized in that: The oil drain valve (13) is also connected to the oil boiler (6) via a third pipe, and the third pipe is connected to the oil recovery pipe (10); the bottoms of the condenser (7), the ammonia circulation tank (5) and the evaporator (8) are connected to the oil boiler via pipes for regularly draining the refrigeration oil remaining at the bottoms of the respective condensers (7).

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