Refrigerant recovery system and control method

Abstract

The present application relates to the first compressor field, specifically to a kind of refrigerant recovery system and control method, mixed tank, for storing refrigerant to be recycled;First heat exchanger, with first passage and second passage are coupled with each other;The inlet of first passage is communicated with the outlet of mixed tank;First compressor, its inlet is communicated with the outlet of first passage;Separation device, its inlet is communicated with the outlet of first compressor;Separation device includes first outlet and second outlet, second passage is easy adsorption component from first outlet discharge, difficult adsorption component is discharged from second outlet, part of heat of difficult adsorption component discharged from second outlet is used to make the refrigerant flowing through first passage temperature rise;First storage device, for storing easy adsorption component from first outlet discharge;Second storage device, for storing difficult adsorption component from second outlet discharge, to effectively utilize the heat generated in the process of adsorption separation, improve separation efficiency.

Description

Technical Field

[0001] This invention relates to the field of first compressors, and more specifically to a refrigerant recovery system and control method. Background Technology

[0002] Hydrofluorocarbon (HFC) refrigerants have a high global warming potential (GWP) and will be phased out in the coming decades. Recycling and reusing high-GWP refrigerants can minimize their environmental impact and help prevent ozone depletion and global warming. The separation and purification of mixed refrigerants is one of the main challenges in refrigerant recycling and purification systems, especially the separation and purification of azeotropic or near-azeotropic refrigerants. Due to their similar boiling points, conventional separation methods such as distillation are not feasible. Various technologies have been developed for separating mixed refrigerants, including extractive distillation using ionic liquids, membrane separation, and adsorption. However, extractive distillation requires the introduction of additional organic entrainers, and membrane separation has high requirements for membrane materials, which may further complicate the separation process. Adsorption separation technology has lower costs, higher separation purity, and greater application prospects.

[0003] Industrially used adsorption separation processes include temperature swing adsorption (TSA), pressure swing adsorption (PSA), rinsing adsorption (RIA), and displacement adsorption. PSA processes adsorb at higher pressures and desorb at lower pressures, utilizing the difference in partial pressure of the adsorbate to complete the cycle. Because pressure changes are much faster than changes in other parameters, and the process does not require the introduction of additional desorbents or rinsing agents, the equipment is relatively simple and energy-efficient.

[0004] The adsorption separation process involves both endothermic and exothermic reactions; specifically, adsorption is exothermic and desorption is endothermic. In the gas adsorption separation process, the heat of adsorption is relatively large, and the adsorption process will cause the temperature of the unadsorbed gas to rise. The heat of adsorption is not effectively utilized, which is not conducive to energy conservation.

[0005] There is currently no good solution to the above-mentioned technical problems. Summary of the Invention

[0006] To effectively utilize the heat generated during the adsorption separation process and improve separation efficiency, a refrigerant recovery system and control method are proposed.

[0007] This invention provides a refrigerant recovery system for separating easily adsorbed and difficult-to-adsorb components in a refrigerant, comprising:

[0008] A mixing tank is used to store refrigerant to be recovered;

[0009] A first heat exchanger has a first passage and a second passage coupled to each other; the inlet of the first passage is connected to the outlet of the mixing tank.

[0010] The first compressor has its inlet connected to the outlet of the first passage;

[0011] A separation device, the inlet of which is connected to the outlet of the first compressor; the separation device includes a first outlet and a second outlet, the easily adsorbed component is discharged from the first outlet and the difficult-to-adsorbed component is discharged from the second outlet, and part of the heat of the difficult-to-adsorbed component discharged from the second outlet is used to raise the temperature of the refrigerant flowing through the first passage.

[0012] A first storage device is used to store easily adsorbed components discharged from the first outlet;

[0013] The second storage device is used to store the recalcitrant components discharged from the second outlet.

[0014] Preferably, the separation device includes a first separation tank and a second separation tank;

[0015] The first separation tank and the second separation tank have a double-layer shell structure;

[0016] The cavity between the two shells of the first separator is a first interlayer, and the inner cavity of the first separator is a first inner cavity; the cavity between the two shells of the second separator is a second interlayer, and the inner cavity of the second separator is a second inner cavity.

[0017] The outlet of the first compressor can be selectively connected to the first interlayer and the second interlayer, and both the first inner cavity and the second inner cavity are provided with adsorbent.

[0018] Preferably, a first control valve is provided on the pipe connecting the outlet of the first compressor and the inlet of the first interlayer, a second control valve is provided on the pipe connecting the outlet of the first compressor and the inlet of the second interlayer, a third control valve is provided on the pipe connecting the outlet of the first interlayer and the inlet of the second inner cavity, and a fourth control valve is provided on the pipe connecting the outlet of the second interlayer and the inlet of the first inner cavity.

[0019] Preferably, the first storage device includes a vacuum pump, a tenth control valve is provided on the pipe between the air inlet of the vacuum pump and the air inlet of the first inner cavity, and an eleventh control valve is provided on the pipe between the air inlet of the vacuum pump and the air inlet of the second inner cavity.

[0020] The separation device includes an outlet valve assembly, through which the difficult-to-adsorb components discharged from the first separation tank and the second separation tank are discharged to the second storage device.

[0021] Preferably, a fifth control valve is provided on the pipe between the outlet of the first inner cavity and the inlet of the second passage, and a sixth control valve is provided on the pipe between the outlet of the second inner cavity and the inlet of the second passage.

[0022] Preferably, the refrigerant recovery system is further provided with a second heat exchanger, which includes a third passage and a fourth passage;

[0023] An eighth control valve is installed on the pipe between the outlet of the first inner cavity and the inlet of the third passage, and a ninth control valve is installed on the pipe between the outlet of the second inner cavity and the inlet of the third passage.

[0024] The fourth passage is connected to the second passage via a refrigerant circulation pipeline. A second compressor is installed on the refrigerant circulation pipeline. The outlet of the second compressor is connected to the inlet of the second passage, and the inlet of the second compressor is connected to the outlet of the fourth passage.

[0025] Preferably, an expansion valve is provided on the refrigerant circulation pipeline between the outlet of the second passage and the inlet of the fourth passage.

[0026] Preferably, a seventh control valve is provided on the pipe between the outlet of the first inner cavity and the outlet of the second inner cavity.

[0027] The present invention also provides a control method for the aforementioned refrigerant recovery system, comprising the following steps:

[0028] Step 1: Control the second control valve, the fourth control valve, and the eleventh control valve to open, control the outlet valve group to close, and control the vacuum pump to start;

[0029] The first step is maintained for a first preset duration, and then the next step is executed.

[0030] Step 2: Control the outlet valve group to the first mode, close all other control valves, and stop the vacuum pump; when the outlet valve group is in the first mode, the difficult-to-adsorb components in the first inner cavity are discharged from the first inner cavity; control Step 2 to be maintained for a second preset time, and then execute the next step;

[0031] Step 3: Control the outlet valve group to the second mode, close all other control valves, and stop the vacuum pump; when the outlet valve group is in the first mode, the first inner cavity and the second inner cavity are connected;

[0032] The third step is maintained for a third preset duration, and then the next step is executed.

[0033] Step 4: Control the first control valve, the third control valve, and the tenth control valve to open, control the outlet valve group to close, and control the vacuum pump to open;

[0034] The fourth step is maintained for a fourth preset duration, and then the next step is executed.

[0035] Step 5: Control the outlet valve assembly to the third mode, and close all other control valves; when the outlet valve assembly is in the third mode, the difficult-to-adsorb components in the second inner cavity are discharged from the second inner cavity;

[0036] The fifth step is maintained for a preset duration, and then the next step is executed.

[0037] Step Six: Control the outlet valve assembly to the second mode, and close all other control valves;

[0038] The sixth step is maintained for a preset duration, and then the first step is executed.

[0039] And so it goes.

[0040] Preferred:

[0041] When the refrigerant recovery system is equipped with a second compressor, when the refrigerant recovery system is in step one, the second compressor is also controlled to start and continue for the first preset duration; when the refrigerant recovery system is in step four, the second compressor is also controlled to start and continue for the fourth preset duration.

[0042] This invention heats the refrigerant entering the first compressor by removing the difficult-to-adsorb components discharged from the separation device, thereby increasing the temperature and pressure of the refrigerant discharged from the first compressor. On the one hand, heating the easily adsorbed components at high temperature improves desorption efficiency; on the other hand, the high-pressure refrigerant facilitates the adsorption of easily adsorbed components by the adsorbent, thus improving the recovery rate of the mixed refrigerant and the energy utilization rate of the process. Attached Figure Description

[0043] To more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings in the following description are merely exemplary, and those skilled in the art can derive other embodiments based on the provided drawings without creative effort.

[0044] The structures, proportions, sizes, etc. illustrated in this specification are only for the purpose of assisting those skilled in the art in understanding and reading the content disclosed herein, and are not intended to limit the conditions under which the present invention can be implemented. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in the proportions, or adjustments to the size, without affecting the effects and objectives that the present invention can produce, should still fall within the scope of the technical content disclosed in the present invention.

[0045] Figure 1 This is a schematic diagram of the refrigerant recovery system of the present invention, in Embodiment 1.

[0046] Figure 2 This is a schematic diagram of the refrigerant recovery system in Embodiment 2 of the present invention.

[0047] The reference numerals in the attached figures are as follows:

[0048] 1. First separating tank; 101. First jacket; 102. First inner cavity; 2. Second separating tank; 201. Second jacket; 202. Second inner cavity; 3. Mixing tank; 401. First heat exchanger; 402. Second heat exchanger; 4011. First passage; 4012. Second passage; 4021. Third passage; 4022. Fourth passage; 501. First compressor; 502. Second compressor; 601. First control valve; 602. Second control valve; 603. Third control valve; 604. Fourth control valve; 605. Fifth control valve; 606. Sixth control valve; 607. Seventh control valve; 608. Eighth control valve; 609. Ninth control valve; 6 10. Tenth control valve; 611. Eleventh control valve; 7. Refrigerant circulation pipeline; 701. Expansion valve; 8. Vacuum pump; 901. Flash tank; 902. Oil separator; 903. First impurity storage tank; 904. Second impurity storage tank; 905. First shut-off valve; 906. Second shut-off valve; 907. First buffer tank; 908. Second buffer tank; 909. Gas-liquid separator; 910. Solenoid valve; 911. First check valve; 912. Second check valve; 913. First recovery container; 914. First condenser; 915. Second condenser; 916. First fan; 917. Second fan; 918. Second recovery container; 919. Dryer filter. Detailed Implementation

[0049] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present invention or its application or use. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0050] It should be noted that the terminology used herein is for the purpose of describing particular implementations only and is not intended to limit the exemplary implementations according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise.

[0051] Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or their components; the terms "comprising," "including," or any other variations thereof are intended to cover a non-exclusive inclusion, such that an article or system comprising a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such an article or system. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the article or system that includes said element.

[0052] It should be understood that the term "and / or" used in this article is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this article generally indicates that the preceding and following related objects have an "or" relationship.

[0053] Unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps set forth in these embodiments do not limit the scope of the invention. It should also be understood that, for ease of description, the dimensions of the various parts shown in the drawings are not drawn to actual scale. Techniques, methods, and devices known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters in the following figures denote similar items; therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0054] In the description of this invention, it should be understood that the orientation or positional relationship indicated by directional terms such as "front, back, up, down, left, right", "horizontal, vertical, horizontal" and "top, bottom" is generally based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing this invention and simplifying the description. Unless otherwise stated, these directional terms do not indicate or imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on the scope of protection of this invention; the directional terms "inner" and "outer" refer to the inner and outer contours relative to the outline of each component itself.

[0055] For ease of description, spatial relative terms such as "above," "on top of," "on the upper surface of," "above," etc., are used herein to describe the spatial positional relationship of a device or feature as shown in the figures to other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation beyond the orientation of the device as described in the figures. For example, if the device in the figures were inverted, a device described as "above" or "on top of" other devices or structures would subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein will be interpreted accordingly.

[0056] Furthermore, it should be noted that the use of terms such as "first" and "second" to define components is merely for the purpose of distinguishing the corresponding components, and does not imply any sequential order; unless otherwise stated, the above terms have no special meaning and therefore should not be construed as limiting the scope of protection of this invention.

[0057] This invention relates to the field of first compressors, and more specifically to a refrigerant recovery system and control method.

[0058] Hydrofluorocarbon (HFC) refrigerants have a high global warming potential (GWP) and will be phased out in the coming decades. Recycling and reusing high-GWP refrigerants can minimize their environmental impact and help prevent ozone depletion and global warming. The separation and purification of mixed refrigerants is one of the main challenges in refrigerant recycling and purification systems, especially the separation and purification of azeotropic or near-azeotropic refrigerants. Due to their similar boiling points, conventional separation methods such as distillation are not feasible. Various technologies have been developed for separating mixed refrigerants, including extractive distillation using ionic liquids, membrane separation, and adsorption. However, extractive distillation requires the introduction of additional organic entrainers, and membrane separation has high requirements for membrane materials, which may further complicate the separation process. Adsorption separation technology has lower costs, higher separation purity, and greater application prospects.

[0059] Industrially used adsorption separation processes include temperature swing adsorption (TSA), pressure swing adsorption (PSA), rinsing adsorption (RIA), and displacement adsorption. PSA processes adsorb at higher pressures and desorb at lower pressures, utilizing the difference in partial pressure of the adsorbate to complete the cycle. Because pressure changes are much faster than changes in other parameters, and the process does not require the introduction of additional desorbents or rinsing agents, the equipment is relatively simple and energy-efficient.

[0060] The adsorption separation process involves both endothermic and exothermic reactions; specifically, adsorption is exothermic and desorption is endothermic. In the gas adsorption separation process, the heat of adsorption is relatively large, and the adsorption process will cause the temperature of the unadsorbed gas to rise. The heat of adsorption is not effectively utilized, which is not conducive to energy conservation.

[0061] To address the aforementioned technical problems, a refrigerant recovery system and control method are proposed. This aims to effectively utilize the heat generated during the adsorption separation process and improve separation efficiency.

[0062] This invention provides a refrigerant recovery system for separating easily adsorbed and difficult-to-adsorb components in a refrigerant, such as... Figure 1-2 As shown, it includes:

[0063] Mixing tank 3 is used to store refrigerant to be recycled;

[0064] The first heat exchanger 401 has a first passage 4011 and a second passage 4012 coupled to each other; the inlet of the first passage 4011 is connected to the outlet of the mixing tank 3.

[0065] The inlet of the first compressor 501 is connected to the outlet of the first passage 4011;

[0066] The separation device has its inlet connected to the outlet of the first compressor 501; the separation device includes a first outlet and a second outlet, the easily adsorbed component is discharged from the first outlet and the difficult-to-adsorb component is discharged from the second outlet through the second passage 4012, and part of the heat of the difficult-to-adsorb component discharged from the second outlet is used to raise the temperature of the refrigerant flowing through the first passage 4011.

[0067] A first storage device is used to store easily adsorbed components discharged from the first outlet;

[0068] The second storage device is used to store the recalcitrant components discharged from the second outlet.

[0069] The terms "difficult-to-adsorb components" and "easily-adsorbed components" used in the claims and specification are relative. Different adsorbents are required for different refrigerants to adsorb the "easily-adsorbed components" in the refrigerant. Correspondingly, gases that are more difficult to adsorb by an adsorbent are called "difficult-to-adsorb components." Different adsorbents correspond to different "easily-adsorbed components," and the adsorbent needs to be determined based on the refrigerant to be separated.

[0070] Separation is achieved by using an adsorbent with different adsorption affinities for different components of a mixed refrigerant. The adsorbent in the inner cavity can be activated carbon, zeolite, or metal-organic framework materials. For azeotropic / near-azeotropic refrigerants, the adsorbent has a strong adsorption capacity for one component of the azeotropic / near-azeotropic refrigerant, which is the easily adsorbed component, and is obtained by desorption during vacuuming of the separation tank.

[0071] In this application, "inner cavity" includes "first inner cavity 102 and second inner cavity 202"; "separation tank" includes "first separation tank and second separation tank"; "interlayer" includes "first interlayer 101 and second interlayer 201"; "mutual coupling" in this application refers to a connection method that can "exchange heat".

[0072] "Part of the heat from the difficult-to-adsorb component discharged from the second outlet is used to heat the refrigerant flowing through the first heat exchanger 401" includes the difficult-to-adsorb component flowing directly through the first heat exchanger 401 and heating the refrigerant flowing through the first heat exchanger 401 through coupling; it also includes the difficult-to-adsorb component first heating a medium, which then heats the refrigerant flowing through the first heat exchanger 401.

[0073] Furthermore, adsorbents can adsorb easily adsorbed components from refrigerants. By adsorbing these easily adsorbed components, the difficult-to-adsorb components cannot be adsorbed and are expelled, thus completing the separation of easily and difficult-to-adsorbed components. This process is existing technology. When the concentration of the refrigerant to be adsorbed is constant, the lower the temperature and the higher the pressure, the greater the adsorption capacity of the adsorbent (faster adsorption time, greater adsorption amount); conversely, the higher the temperature and the lower the pressure, the smaller the adsorption capacity of the adsorbent (slower adsorption time, less adsorption amount). That is, cooling and pressurizing are beneficial to the adsorption process, while heating and depressurizing are beneficial to the desorption process. Also, because the components have a large heat of adsorption and a small specific heat capacity, the adsorbent releases heat when adsorbing easily adsorbed components, causing the temperature of the difficult-to-adsorbed components to rise.

[0074] The higher the temperature of the refrigerant gas entering the first compressor 501, the higher the temperature and pressure of the discharged refrigerant gas. Therefore, when this refrigerant recovery system is working, the high-temperature, high-pressure refrigerant compressed by the first compressor 501 comes into contact with the adsorbent in the separation device. Easily adsorbed components are adsorbed by the adsorbent and release heat to the difficult-to-adsorb components. The difficult-to-adsorb components are discharged from the second outlet, while the easily adsorbed components detach from the adsorbent and are discharged from the first outlet. Because the easily adsorbed components release heat during adsorption, the temperature of the difficult-to-adsorb components rises. The increased temperature of the difficult-to-adsorb components, through the second passage 4012 of the first heat exchanger 401, raises the temperature of the refrigerant flowing through the first passage 4011, thus increasing the temperature of the refrigerant before entering the first compressor 501. This improves the working efficiency of the first compressor 501 and increases the temperature and pressure of the gas discharged from the first compressor 501. This is equivalent to recovering heat from the difficult-to-adsorb components, reducing heat waste, lowering refrigerant separation costs, reducing energy consumption, improving refrigerant separation efficiency, and increasing energy utilization.

[0075] The recovered refrigerant is a single-function refrigerant, which can be reused, improving the refrigerant reuse rate and reducing costs.

[0076] The first compressor 501 is preferably an oil-free compressor to avoid the oil in the first compressor 501 causing re-contamination of the refrigerant to be separated.

[0077] A second buffer tank 908 is added after the first compressor 501 to reduce pressure fluctuations in the system and allow the refrigerant gas discharged from the first compressor 501 to smoothly enter the next device.

[0078] Preferably, the separation device includes a first separation tank and a second separation tank;

[0079] The first separation tank 1 and the second separation tank 2 have a double-layer shell structure;

[0080] The cavity between the two shells of the first separation tank 1 is the first interlayer 101, and the inner cavity of the first separation tank 1 is the first inner cavity 102; the cavity between the two shells of the second separation tank 2 is the second interlayer 201, and the inner cavity of the second separation tank 2 is the second inner cavity 202.

[0081] The outlet of the first compressor 501 can be selectively connected to the first interlayer 101 and the second interlayer 201, and an adsorbent is provided in both the first inner cavity 102 and the second inner cavity 202.

[0082] By designing the separator as a double-shell structure, the high-temperature and high-pressure gas discharged from the first compressor 501 first enters the first interlayer 101 or the second interlayer 201 to heat the refrigerant in the first inner cavity 102 and the second inner cavity 202. Compared with the existing method of setting heat exchange tubes inside the inner cavity, where the high-temperature and high-pressure gas discharged from the first compressor 501 first enters the heat exchange tubes, this application uses a double-shell structure. The high-temperature and high-pressure gas entering the interlayer can heat the inner cavity more evenly. Since the inner cavity is wrapped by the outer interlayer, the structure of the interlayer itself also constitutes a heat insulation layer, thereby ensuring the stability of the refrigerant temperature in the inner cavity and effectively improving the desorption efficiency of easily adsorbed components from the adsorbent.

[0083] In addition, the sandwich structure does not occupy the internal space of the separator, ensuring that enough adsorbent can be placed inside the internal cavity, and a large amount of refrigerant can be charged into the internal cavity at one time, thereby improving the refrigerant separation efficiency.

[0084] Moreover, the double-shell structure is simple, easy to manufacture, inexpensive, and easy to clean and maintain.

[0085] Preferably, a first control valve 601 is provided on the pipe connecting the outlet of the first compressor 501 and the inlet of the first interlayer 101, a second control valve 602 is provided on the pipe connecting the outlet of the first compressor 501 and the inlet of the second interlayer 201, a third control valve 603 is provided on the pipe connecting the outlet of the first interlayer 101 and the inlet of the second inner cavity 202, and a fourth control valve 604 is provided on the pipe connecting the outlet of the second interlayer 201 and the inlet of the first inner cavity 102.

[0086] By setting the first control valve 601, the second control valve 602, the third control valve 603 and the fourth control valve 604 mentioned above, the first separation tank and the second separation tank 2 can alternately perform adsorption and desorption of easily adsorbed components, thereby improving the separation efficiency of the refrigerant.

[0087] The working relationship between the first separation tank and the second separation tank 2 is as follows:

[0088] In the first stage: the first inner cavity 102 of the first separation tank 1 is used for adsorption, and the second inner cavity 202 of the second separation tank 2 is used for desorption. The second control valve 602 and the fourth control valve 604 are open, while the first control valve 601 and the third control valve 603 are closed. The high-temperature, high-pressure gas discharged from the first compressor 501 enters the second jacket 201 to heat the second inner cavity 202. The adsorbent that has completed adsorption in the second inner cavity 202 undergoes desorption after heating, and the easily adsorbed components are discharged. The refrigerant heated in the second inner cavity 202 becomes a low-temperature, high-pressure refrigerant. This low-temperature, high-pressure refrigerant enters the first inner cavity 102 through the fourth control valve 604. The easily adsorbed components in the low-temperature, high-pressure refrigerant entering the first inner cavity 102 are adsorbed by the adsorbent in the first inner cavity 102. Because the low temperature and high pressure are favorable for the adsorption process, this improves the adsorption efficiency of the easily adsorbed components in the first inner cavity 102, thus improving the separation efficiency between the easily adsorbed and difficult-to-adsorb components. After the easily adsorbed components are adsorbed, the difficult-to-adsorbed components are enriched in the gas phase and then discharged.

[0089] Second stage: The second inner cavity 202 of the second separator 2 is used for adsorption, and the first inner cavity 102 of the first separator 1 is used for desorption. The second control valve 602 and the fourth control valve 604 are closed, and the first control valve 601 and the third control valve 603 are opened. The high-temperature and high-pressure gas discharged from the first compressor 501 enters the first jacket 101 to heat the first inner cavity 102. The adsorbent that has completed the adsorption work in the first inner cavity 102 is desorbed after being heated, and the easily adsorbed components are discharged. The refrigerant after heating the first inner cavity 102 becomes a low-temperature and high-pressure refrigerant. The low-temperature and high-pressure refrigerant enters the second inner cavity 202 through the third control valve 603. The easily adsorbed components in the low-temperature and high-pressure refrigerant entering the second inner cavity 202 are adsorbed by the adsorbent in the second inner cavity 202, and the difficult-to-adsorb components are enriched in the gas phase. The enriched difficult-to-adsorb components are discharged.

[0090] Then, the first stage of work is carried out again, and so on in a cycle. That is, the first separation tank 1 and the second separation tank 2 alternately perform adsorption and desorption, which improves the gas separation efficiency.

[0091] Preferably, the first storage device includes a vacuum pump 8, a tenth control valve 610 is provided on the pipe between the air inlet of the vacuum pump 8 and the air inlet of the first inner cavity 102, and an eleventh control valve 611 is provided on the pipe between the air inlet of the vacuum pump 8 and the air inlet of the second inner cavity 202.

[0092] The separation device includes an outlet valve assembly, through which the difficult-to-adsorb components discharged from the first separation tank 1 and the second separation tank 2 are discharged to the second storage device.

[0093] Since high temperature and low pressure are conducive to desorption, when desorption is carried out, in addition to injecting high temperature and high pressure gas compressed by the first compressor 501 into the first interlayer 101 or the second interlayer 201, the vacuum pump 8 is set to evacuate the first inner cavity 102 or the second inner cavity 202 to reduce the pressure of the inner cavity and improve the efficiency of desorption of easily adsorbed components from the adsorbent; moreover, the vacuum pump 8 also plays a driving role in the airflow, which accelerates the speed at which the desorbed gas flows out of the inner cavity, which is conducive to improving the recovery and storage efficiency of easily adsorbed components after desorption.

[0094] When the easily adsorbed component in the first inner cavity 102 desorbs from the adsorbent, the tenth control valve 610 opens and the eleventh control valve 611 closes, and the vacuum pump 8 draws a vacuum from the first inner cavity 102; when the easily adsorbed component in the second inner cavity 202 desorbs from the adsorbent, the tenth control valve 610 closes and the eleventh control valve 611 opens, and the vacuum pump 8 draws a vacuum from the second inner cavity 202.

[0095] Preferred, such as Figure 2 As shown, a fifth control valve 605 is provided on the pipe between the outlet of the first inner cavity 102 and the inlet of the second passage 4012, and a sixth control valve 606 is provided on the pipe between the outlet of the second inner cavity 202 and the inlet of the second passage 4012.

[0096] Example 1: Heating the gas before it enters the first compressor 501:

[0097] At this time, the outlet valve assembly includes a fifth control valve 605 and a sixth control valve 606. When the first inner cavity 102 discharges the refrigerant-difficult-to-adsorb component, the fifth control valve 605 opens and the sixth control valve 606 closes; when the second inner cavity 202 discharges the refrigerant-difficult-to-adsorb component, the fifth control valve 605 closes and the sixth control valve 606 opens, thereby realizing the alternating discharge of the refrigerant-difficult-to-adsorb component from the first inner cavity 102 and the second inner cavity 202. This allows the first inner cavity 102 and the second inner cavity 202 to prepare space for the next refrigerant adsorption and separation, which is beneficial to improving the working efficiency of the first separation tank 1 and the second separation tank 2.

[0098] The high-temperature, difficult-to-adsorb components discharged from the first inner cavity 102 and the second inner cavity 202 directly flow through the first heat exchanger 401 to heat the refrigerant flowing into the first compressor 501, thus avoiding heat loss of the difficult-to-adsorb components during the flow process and improving the heat utilization rate of the difficult-to-adsorb components.

[0099] Preferred, such as Figure 1 As shown, the refrigerant recovery system is also provided with a second heat exchanger 402, which includes a third passage 4021 and a fourth passage 4022.

[0100] An eighth control valve 608 is provided on the pipe between the outlet of the first inner cavity 102 and the inlet of the third passage 4021, and a ninth control valve 609 is provided on the pipe between the outlet of the second inner cavity 202 and the inlet of the third passage 4021.

[0101] The fourth passage 4022 is connected to the second passage 4012 via a refrigerant circulation pipe 7. A second compressor 502 is installed on the refrigerant circulation pipe 7. The outlet of the second compressor 502 is connected to the inlet of the second passage 4012, and the inlet of the second compressor 502 is connected to the outlet of the fourth passage 4022.

[0102] A second embodiment for heating the gas before it enters the first compressor 501:

[0103] At this time, the outlet valve assembly includes an eighth control valve 608 and a ninth control valve 609. When the first inner cavity 102 discharges the difficult-to-adsorb component, the eighth control valve 608 opens and the ninth control valve 609 closes; when the second inner cavity 202 discharges the difficult-to-adsorb component, the eighth control valve 608 closes and the ninth control valve 609 opens. Compared with Example 1, in Example 2, the high-temperature difficult-to-adsorb component discharged from the first inner cavity 102 and the second inner cavity 202 does not flow directly through the first heat exchanger 401, but flows through the second heat exchanger 402. A refrigerant circulation pipeline 7 is provided between the second heat exchanger 402 and the first heat exchanger 401. The high-temperature difficult-to-adsorb component heats the refrigerant in the refrigerant circulation pipeline 7, and the heated refrigerant is then set... In the circulation pipeline, the second compressor 502 pressurizes and heats the refrigerant. The high-temperature refrigerant, after being pressurized and heated by the second compressor 502, flows through the first heat exchanger 401 and is heated before entering the first compressor 501. This effectively increases the temperature of the refrigerant entering the first compressor 501. After being heated by the first heat exchanger 401, the refrigerant temperature decreases. The cooled refrigerant then passes through the second heat exchanger 402 again, absorbing heat from the poorly adsorbed components to raise its temperature. After absorbing heat from the poorly adsorbed components, the refrigerant temperature rises even further after passing through the second compressor 502, thereby improving the compression efficiency of the first compressor 501. This cycle continues, with the refrigerant temperature increased by heating the refrigerant through the poorly adsorbed components, thus increasing the compression efficiency of the second compressor 502 and further increasing the temperature of the refrigerant discharged from the second compressor 502. The refrigerant discharged from the second compressor 502 then reheats the refrigerant before the first compressor 501 through the first heat exchanger 401, and so on. Compared to the first embodiment, the refrigerant temperature before the first compressor 501 in the second embodiment is higher.

[0104] Using the second heat exchanger 402 allows for heat exchange with the refrigerant within the circulation pipe 7, facilitating more precise temperature control. Thus, by fully utilizing the compressor's work, the increased temperature of the refrigerant in the first passage 4011 can be regulated. Furthermore, the increased pressure of the refrigerant discharged from the first compressor 501 helps reduce the energy required for pressurization during the system's adsorption process.

[0105] Preferably, an expansion valve 701 is provided on the refrigerant circulation pipeline 7 between the outlet of the second passage 4012 and the inlet of the fourth passage 4022.

[0106] After the refrigerant is heated by the first heat exchanger 401, the temperature of the refrigerant decreases. The temperature of the refrigerant then decreases further after passing through the expansion valve 701. At this point, the temperature of the refrigerant is low, even below zero degrees Celsius.

[0107] The temperature difference between the refrigerant and the poorly adsorbed component is greater after passing through the expansion valve 701. The refrigerant absorbs more heat from the poorly adsorbed component, and some of the component condenses after heat exchange with the refrigerant. In other words, the refrigerant passing through the expansion valve 701 condenses the poorly adsorbed component, making it easier to recover and store. Therefore, by setting up a refrigerant recovery pipeline, a second compressor 502, and an expansion valve 701, not only is the heat from the poorly adsorbed component recovered to improve the compression efficiency of the first compressor 501 and increase the pressure and temperature of the gas discharged from the first compressor 501, but the refrigerant also causes the poorly adsorbed component to condense, improving the recovery efficiency of the poorly adsorbed component.

[0108] Preferably, a seventh control valve 607 is provided on the pipe between the outlet of the first inner cavity 102 and the outlet of the second inner cavity 202.

[0109] The control valve assembly also includes a seventh control valve 607. Embodiment 1 includes: a seventh control valve 607, a fifth control valve 605, and a sixth control valve 606; Embodiment 2 includes: a seventh control valve 607, an eighth control valve 608, and a ninth control valve 609.

[0110] When one of the difficult-to-adsorb components in the first inner cavity 102 or the second inner cavity 202 is discharged, the other completes vacuum desorption. At this time, the pressure difference between the two inner cavities is large, and the next step for the inner cavity that has completed vacuum desorption is to inject refrigerant to carry out the adsorption of easily adsorbed components, but low pressure is not conducive to adsorption. When one of the difficult-to-adsorbed components in the first inner cavity 102 or the second inner cavity 202 is discharged and the other completes vacuum desorption, the seventh control valve 607 is opened to balance the pressure of the two inner cavities. That is, the pressure of the inner cavity that discharged the difficult-to-adsorbed component is transferred to the inner cavity that completed the vacuum desorption work to relieve pressure, increase the pressure of the inner cavity that completed the vacuum desorption work, prepare for the subsequent adsorption of easily adsorbed components, and thus improve the adsorption efficiency of easily adsorbed components.

[0111] The contaminated refrigerant mixture contains water, oil, acid, non-condensable gases, and solid particulate impurities. When the refrigerant recovery system is used to recover the mixed refrigerant, a flash tank 901 and an oil separator are sequentially installed between the mixing tank 3 and the first heat exchanger 401. A pressure reducing valve is installed between the mixing tank 3 and the flash tank 901. A dryer filter 919 is installed between the flash tank 901 and the oil separator. The bottom of the flash tank 901 is connected to a first impurity storage tank 903 via a first shut-off valve 905, and the bottom of the oil separator is connected to a second impurity storage tank 904 via a second shut-off valve 906.

[0112] Thus, the mixed refrigerant discharged from mixing tank 3 enters flash tank 901 through pressure reducing valve, where it undergoes coarse separation. The mixed refrigerant after pressure reducing valve rapidly vaporizes within flash tank 901, changing from a liquid to a gaseous state. The bottom of flash tank 901 contains impurities such as oil and water. The separated oil and water are stored in the first impurity tank via the first shut-off valve 905. The gaseous refrigerant in flash tank 901 enters the dryer filter 919 from the top outlet. This dryer filter 919 further separates water, acid, and small solid particles from the gaseous refrigerant. The separated mixed refrigerant then enters oil separator 902 for oil removal. The removed oil is recovered to the second impurity storage tank 904 via the second shut-off valve 906. The mixed refrigerant discharged from the oil separator flows through the first heat exchanger 401. The dryer filter 919 can be made of zeolite, activated carbon, silica gel, alumina, or metal-organic framework materials.

[0113] The second storage device includes a first buffer tank 907, a gas-liquid separator 909, a first condenser 914, and a first recovery container 913. Before being stored, the difficult-to-adsorb components after passing through the first heat exchanger 401 or the second heat exchanger 402 enter the first buffer tank 907. The first buffer tank 907 can balance the pressure and purity of the difficult-to-adsorb components separated from the two separators.

[0114] The difficult-to-adsorb components flow smoothly out of the first buffer tank 907 and enter the first condenser 914 to condense into liquid. Since the mixed refrigerant contains non-condensable gases, the refrigerant flowing out of the first condenser 914 enters the gas-liquid separator 909. The top of the gas-liquid separator 909 is equipped with a solenoid valve 910. In the gas-liquid separator 909, the non-condensable gases are discharged through the solenoid valve 910, and the mixed refrigerant is discharged from the gas-liquid separator 909 and enters the first recovery container 913 through the first check valve 911.

[0115] The first storage device includes a second condenser 915 and a second recovery container 918; the gaseous refrigerant discharged by the vacuum pump 8 is condensed into a liquid by the second condenser 915 and then flows into the second recovery container 918 through the second check valve 912.

[0116] To improve the condensing efficiency of the first condenser 914 and the second condenser 915, a first fan 916 is provided to accelerate the heat exchange of the first condenser 914; and a second fan 917 is provided to accelerate the heat exchange of the second condenser 915.

[0117] The present invention also provides a control method for the aforementioned refrigerant recovery system, the control method comprising the following steps:

[0118] Step 1: Control the second control valve 602, the fourth control valve 604 and the eleventh control valve 611 to open, control the outlet valve group to close, and control the vacuum pump 8 to start;

[0119] The first step is maintained for a first preset duration, and then the next step is executed.

[0120] Step 2: Control the outlet valve group to the first mode, close all other control valves, and stop the vacuum pump 8; when the outlet valve group is in the first mode, the difficult-to-adsorb components in the first inner cavity 102 are discharged from the first inner cavity 102; control Step 2 to be maintained for a second preset time, and then execute the next step;

[0121] Step 3: Control the outlet valve group to the second mode, close all other control valves, and stop the vacuum pump 8; when the outlet valve group is in the first mode, the first inner cavity 102 and the second inner cavity 202 are connected;

[0122] The third step is maintained for a third preset duration, and then the next step is executed.

[0123] Step 4: Control the first control valve 601, the third control valve 603 and the tenth control valve 610 to open, control the outlet valve group to close, and control the vacuum pump 8 to open;

[0124] The fourth step is maintained for a fourth preset duration, and then the next step is executed.

[0125] Step 5: Control the outlet valve group to the third mode, and close all other control valves; when the outlet valve group is in the third mode, the difficult-to-adsorb components in the second inner cavity 202 are discharged from the second inner cavity 202;

[0126] The fifth step is maintained for a preset duration, and then the next step is executed.

[0127] Step Six: Control the outlet valve assembly to the second mode, and close all other control valves;

[0128] The sixth step is maintained for a preset duration, and then the first step is executed.

[0129] And so it goes.

[0130] Step 1: The second control valve 602, the fourth control valve 604, and the eleventh control valve 611 are opened, the outlet valve group is closed, and the vacuum pump 8 is started and maintained for a first preset time.

[0131] Within a first preset time period, the mixed refrigerant enters the second interlayer 201 through the second control valve 602 to heat the second inner cavity 202, causing the temperature inside the second inner cavity 202 to rise. At the same time, the vacuum pump 8 starts to evacuate the second inner cavity 202, reducing the pressure inside the second inner cavity 202. The easily adsorbed components adsorbed by the adsorbent in the second inner cavity 202 are desorbed and flow out through the eleventh control valve 611 and the vacuum pump 8 driven by the vacuum pump 8, completing the desorption. Meanwhile, the refrigerant in the second interlayer 201 continues to flow into the first inner cavity 102 through the fourth control valve 604. The easily adsorbed components contained in the refrigerant are adsorbed by the adsorbent in the first inner cavity 102 and release heat to the difficult-to-adsorb components, thus enriching the difficult-to-adsorb components in the first inner cavity 102.

[0132] Step 2: The outlet valve group is in the first mode, all other control valves are closed, the vacuum pump 8 stops, and the second preset time is maintained;

[0133] During the second preset time period, the outlet valve group is in the first mode, and the difficult-to-adsorb components in the first inner cavity 102 flow out through the outlet valve group, and the concentration of the difficult-to-adsorb components in the first inner cavity 102 decreases.

[0134] Step 3: The outlet valve group is in the second mode, all other control valves are closed, the vacuum pump 8 stops, and the cycle remains in the third preset time.

[0135] During the third preset time period, the outlet valve assembly is in the second mode. In this mode, the first inner cavity 102 and the second inner cavity 202 are connected. Since the pressure in the second inner cavity 202 is low due to the suction effect of the vacuum pump 8 in step one, when the first inner cavity 102 and the second inner cavity 202 are connected, some of the difficult-to-adsorb components in the first inner cavity 102 flow to the second inner cavity 202, causing the pressure inside the second inner cavity 202 to increase. This prepares the second inner cavity 202 for the adsorbent to adsorb easily adsorbed components in the next cycle. To explain, higher pressure is more conducive to adsorption. When a certain amount of refrigerant is charged into the inner cavity, the initial pressure of the inner cavity is higher, and the pressure after the refrigerant is charged is also higher, thereby improving the adsorption effect of the adsorbent on easily adsorbed components.

[0136] Step 4: The first control valve 601, the third control valve 603 and the tenth control valve 610 are opened, the outlet valve group is closed, and the vacuum pump 8 is turned on, and the operation is maintained for a fourth preset time.

[0137] Within the fourth preset time period, the mixed refrigerant enters the first interlayer 101 through the first control valve 601 to heat the first inner cavity 102, causing the temperature inside the first inner cavity 102 to rise. At the same time, the vacuum pump 8 starts to evacuate the first inner cavity 102, reducing the pressure inside the first inner cavity 102. The easily adsorbed components adsorbed by the adsorbent in the first inner cavity 102 are desorbed and flow out through the tenth control valve 610 and the vacuum pump 8 driven by the vacuum pump 8, completing the desorption. Meanwhile, the refrigerant in the first interlayer 101 continues to flow into the second inner cavity 202 through the third control valve 603. The easily adsorbed components contained in the refrigerant are adsorbed by the adsorbent in the second inner cavity 202 and release heat to the difficult-to-adsorb components, thus enriching the difficult-to-adsorb components in the second inner cavity 202.

[0138] Step 5: The outlet valve group is in the third mode, all other control valves are closed, and this is maintained for the fifth preset time.

[0139] Within the fifth preset time period, the outlet valve group is in the third mode, and the difficult-to-adsorb components in the second inner cavity 202 flow out through the outlet valve group, and the concentration of the difficult-to-adsorb components in the second inner cavity 202 decreases.

[0140] Step Six: The outlet valve group is in the second mode, and all other control valves are closed for a preset duration.

[0141] Within the sixth preset time period, the outlet valve assembly is in the second mode. In this mode, the first inner cavity 102 and the second inner cavity 202 are connected. Since the pressure of the first inner cavity 102 is low due to the suction effect of the vacuum pump 8 in step four, when the second inner cavity 202 and the first inner cavity 102 are connected, some of the difficult-to-adsorb components in the second inner cavity 202 flow to the first inner cavity 102, which increases the pressure in the first inner cavity 102, so that the first inner cavity 102 is ready for the adsorbent to adsorb the easily adsorbed components in the next adsorbent.

[0142] Preferred:

[0143] When the refrigerant recovery system is equipped with a second compressor 502, when the refrigerant recovery system is in step one, the second compressor 502 is also controlled to start and continue for the first preset duration; when the refrigerant recovery system is in step four, the second compressor 502 is also controlled to start and continue for the fourth preset duration.

[0144] In step one, the refrigerant continuously flows through the first heat exchanger 401. During this time, the second compressor 502 continuously heats the refrigerant flowing through the first heat exchanger 401 for the same duration as in step one. Similarly, in step four, the refrigerant continuously flows through the first heat exchanger 401, and the second compressor 502 continuously heats the refrigerant flowing through the first heat exchanger 401 for the same duration as in step four. This not only heats the refrigerant flowing through the first heat exchanger 401 but also avoids the second compressor 502 continuously heating the refrigerant that is not flowing in the first heat exchanger 401, which would reduce the temperature difference between the first passage 4011 and the second passage 4012, thus decreasing the heating efficiency. This improves the heating efficiency of the refrigerant.

[0145] When the refrigerant recovery system is working:

[0146] The second control valve 602, the fourth control valve 604, and the eleventh control valve 611 are open, while all other control valves are closed. At this time, the refrigerant discharged from the compressor has a high temperature and pressure. This refrigerant enters the second jacket 201 and heats the adsorbent in the second inner cavity 202, where the easily adsorbed components have already been adsorbed. Simultaneously, the vacuum pump 8 starts to evacuate the second inner cavity 202. Under the high temperature and low pressure environment, the easily adsorbed components in the second inner cavity 202 are quickly desorbed from the adsorbent (this process can be called high temperature vacuum desorption). The desorbed easily adsorbed components are then pumped out by the vacuum pump. After being driven by 8, the refrigerant is discharged from the outlet of vacuum pump 8 and collected; at the same time, the temperature of the refrigerant after being heated by the second inner cavity 202 in the second interlayer 201 decreases, but the pressure is still very high. The refrigerant with the reduced temperature is discharged from the second interlayer 201 and enters the first inner cavity 102 through the fourth control valve 604; in the first inner cavity 102, the refrigerant comes into contact with the adsorbent, wherein the easily adsorbed components in the refrigerant are adsorbed by the adsorbent; since the refrigerant entering the first inner cavity 102 has a high pressure and low temperature, the adsorption efficiency of the easily adsorbed components in the first inner cavity 102 is high.

[0147] After the easily adsorbed component in the first inner cavity 102 is adsorbed, the difficult-to-adsorb component needs to be discharged; the fifth control valve 605 is opened, and all other control valves are closed; since the adsorption process is an exothermic process, the difficult-to-adsorb component stores the heat released during the adsorption process of the easily adsorbed component, the temperature of the difficult-to-adsorb component rises and it is discharged through the fifth control valve 605.

[0148] After the difficult-to-adsorb components in the first inner cavity 102 are discharged, on the one hand, it is necessary to desorb the easily adsorbed components in the first inner cavity 102 and discharge them; on the other hand, the adsorption pressure in the second inner cavity 202 is low due to the vacuum pump 8, so it is necessary to increase the pressure in the second inner cavity 202 to prepare for the next adsorption operation. The seventh control valve 607 is opened, and all other control valves are closed. The difficult-to-adsorbed components remaining in the first inner cavity 102 flow to the second inner cavity 202 through the seventh control valve 607, which increases the pressure in the second inner cavity 202 and reduces the concentration of the difficult-to-adsorbed components in the first inner cavity 102, which is beneficial to the recovery purity of the easily adsorbed components in the first inner cavity 102.

[0149] After the pressure in the first inner cavity 102 and the second inner cavity 202 is equalized, the easily adsorbed components in the first inner cavity 102 undergo desorption, while the easily adsorbed components in the second inner cavity 202 undergo adsorption. At this time, the first control valve 601, the third control valve 603, and the tenth control valve 610 are open, while all other control valves are closed. The refrigerant discharged from the compressor has a high temperature and pressure. This refrigerant enters the first interlayer 101 and heats the adsorbent in the first inner cavity 102 that has already completed the adsorption of easily adsorbed components. At the same time, the vacuum pump 8 starts to evacuate the first inner cavity 102. Under the high temperature and low pressure environment, the easily adsorbed components in the first inner cavity 102 quickly desorb from the first inner cavity 102. Desorption occurs on the adsorbent, and the desorbed easily adsorbed components are discharged from the outlet of the vacuum pump 8 and collected after being driven by the vacuum pump 8. At the same time, the refrigerant temperature decreases after being heated by the first inner cavity 102 in the first interlayer 101, but the pressure remains high. The refrigerant with the reduced temperature is discharged from the first interlayer 101 and enters the second inner cavity 202 through the third control valve 603. In the second inner cavity 202, the refrigerant comes into contact with the adsorbent, and the easily adsorbed components in the refrigerant are adsorbed by the adsorbent. Because the refrigerant entering the second inner cavity 202 has a higher pressure and lower temperature, the adsorption efficiency of the easily adsorbed components in the second inner cavity 202 is higher.

[0150] After the easily adsorbed component in the second inner cavity 202 is adsorbed, the difficult-to-adsorb component needs to be discharged; the sixth control valve 606 is opened, and all other control valves are closed; since the adsorption process is an exothermic process, the difficult-to-adsorb component stores the heat released during the adsorption process of the easily adsorbed component, the temperature of the difficult-to-adsorb component rises and it is discharged through the sixth control valve 606.

[0151] After the difficult-to-adsorb components in the second inner cavity 202 are discharged, on the one hand, it is necessary to desorb the easily adsorbed components in the second inner cavity 202 and discharge them; on the other hand, the adsorption pressure of the first inner cavity 102 through the vacuum pump 8 is low, and it is necessary to increase the pressure of the first inner cavity 102 to prepare for the next adsorption operation in the first inner cavity 102. The seventh control valve 607 is opened, and all other control valves are closed. The difficult-to-adsorbed components remaining in the second inner cavity 202 flow to the first inner cavity 102 through the seventh control valve 607, which increases the pressure of the first inner cavity 102 and at the same time reduces the concentration of the difficult-to-adsorbed components in the second inner cavity 202, which is beneficial to the recovery purity of the easily adsorbed components in the second inner cavity 202.

[0152] The first separation tank 1 and the second separation tank 2 alternately perform the above steps to separate the refrigerant to be separated, which effectively improves the efficiency of recovering, purifying and separating azeotropic or near-azeotropic refrigerants.

[0153] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention. The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the protection scope of the present invention.

Claims

1. A refrigerant recovery system for separating easily adsorbed components and difficult-to-adsorb components in a refrigerant, characterized in that, include: Mixing tank (3) is used to store refrigerant to be recycled; The first heat exchanger (401) has a first passage (4011) and a second passage (4012) coupled to each other; the inlet of the first passage (4011) is connected to the outlet of the mixing tank (3); The inlet of the first compressor (501) is connected to the outlet of the first passage (4011); The separation device has its inlet connected to the outlet of the first compressor (501); the separation device includes a first outlet and a second outlet, the easily adsorbed component is discharged from the first outlet, the difficult-to-adsorb component is discharged from the second outlet, and part of the heat of the difficult-to-adsorbed component discharged from the second outlet is used to heat up the refrigerant flowing through the first passage (4011). A first storage device is used to store easily adsorbed components discharged from the first outlet; A second storage device is used to store the recalcitrant components discharged from the second outlet; The separation device includes a first separation tank (1) and a second separation tank (2). The inner cavity of the first separation tank (1) is a first inner cavity (102), and the inner cavity of the second separation tank (2) is a second inner cavity (202). Adsorbent is provided in both the first inner cavity (102) and the second inner cavity (202). The first storage device includes a vacuum pump (8).

2. The refrigerant recovery system according to claim 1, characterized in that, The first separation tank (1) and the second separation tank (2) are double-shell structures; The cavity between the two shells of the first separation tank (1) is a first interlayer (101); the cavity between the two shells of the second separation tank (2) is a second interlayer (201). The outlet of the first compressor (501) may be selectively connected to the first interlayer (101) and the second interlayer (201).

3. The refrigerant recovery system according to claim 2, characterized in that, A first control valve (601) is provided on the pipe connecting the outlet of the first compressor (501) and the inlet of the first interlayer (101). A second control valve (602) is provided on the pipe connecting the outlet of the first compressor (501) and the inlet of the second interlayer (201). A third control valve (603) is provided on the pipe connecting the outlet of the first interlayer (101) and the inlet of the second inner cavity (202). A fourth control valve (604) is provided on the pipe connecting the outlet of the second interlayer (201) and the inlet of the first inner cavity (102).

4. The refrigerant recovery system according to claim 3, characterized in that, A tenth control valve (610) is provided on the pipe between the air inlet of the vacuum pump (8) and the air inlet of the first inner cavity (102), and an eleventh control valve (611) is provided on the pipe between the air inlet of the vacuum pump (8) and the air inlet of the second inner cavity (202). The separation device includes an outlet valve group, through which the difficult-to-adsorb components discharged from the first separation tank (1) and the second separation tank (2) are discharged to the second storage device.

5. The refrigerant recovery system according to claim 4, characterized in that, A fifth control valve (605) is provided on the pipe between the outlet of the first inner cavity (102) and the inlet of the second passage (4012), and a sixth control valve (606) is provided on the pipe between the outlet of the second inner cavity (202) and the inlet of the second passage (4012).

6. The refrigerant recovery system according to claim 4, characterized in that, The refrigerant recovery system is also provided with a second heat exchanger (402), which includes a third passage (4021) and a fourth passage (4022). An eighth control valve (608) is provided on the pipe between the outlet of the first inner cavity (102) and the inlet of the third passage (4021), and a ninth control valve (609) is provided on the pipe between the outlet of the second inner cavity (202) and the inlet of the third passage (4021). The fourth passage (4022) is connected to the second passage (4012) via a refrigerant circulation pipe (7). A second compressor (502) is installed on the refrigerant circulation pipe (7). The outlet of the second compressor (502) is connected to the inlet of the second passage (4012), and the inlet of the second compressor (502) is connected to the outlet of the fourth passage (4022).

7. The refrigerant recovery system according to claim 6, characterized in that, An expansion valve (701) is provided on the refrigerant circulation pipeline (7) between the outlet of the second passage (4012) and the inlet of the fourth passage (4022).

8. The refrigerant recovery system according to claim 5 or 6, characterized in that, A seventh control valve (607) is provided on the pipe between the outlet of the first inner cavity (102) and the outlet of the second inner cavity (202).

9. A control method for a refrigerant recovery system according to claim 5 or 6, characterized in that, Includes the following steps: Step 1: Control the second control valve (602), the fourth control valve (604) and the eleventh control valve (611) to open, control the outlet valve group to close, and control the vacuum pump (8) to start; The first step is maintained for a first preset duration, and then the next step is executed. Step 2: Control the outlet valve group to be in the first mode, close all other control valves, and stop the vacuum pump (8); when the outlet valve group is in the first mode, the difficult-to-adsorb components in the first inner cavity (102) are discharged from the first inner cavity (102); control the second step to be maintained for a second preset time, and then execute the next step, the first mode being the mode in which the difficult-to-adsorb components in the first inner cavity (102) flow out through the outlet valve group; Step 3: Control the outlet valve group to the second mode, close all other control valves, and control the vacuum pump (8) to stop; When the outlet valve assembly is in the first mode, the first inner cavity (102) and the second inner cavity (202) are connected, and the second mode is the mode in which the first inner cavity (102) and the second inner cavity (202) are connected; The third step is maintained for a third preset duration, and then the next step is executed. Step 4: Control the first control valve (601), the third control valve (603) and the tenth control valve (610) to open, control the outlet valve group to close, and control the vacuum pump (8) to open; The fourth step is maintained for a fourth preset duration, and then the next step is executed. Step 5: Control the outlet valve group to the third mode, and close all other control valves; when the outlet valve group is in the third mode, the difficult-to-adsorb components in the second inner cavity (202) are discharged from the second inner cavity (202), and the third mode is the mode in which the difficult-to-adsorb components in the second inner cavity (202) flow out through the outlet valve group; The fifth step is maintained for a preset duration, and then the next step is executed. Step Six: Control the outlet valve assembly to the second mode, and close all other control valves; The sixth step is maintained for a preset duration, and then the first step is executed. And so it goes.

10. The control method according to claim 9, characterized in that: When the refrigerant recovery system is equipped with a second compressor (502), when the refrigerant recovery system is in step one, the second compressor (502) is also controlled to start and continue for the first preset duration; when the refrigerant recovery system is in step four, the second compressor (502) is also controlled to start and continue for the fourth preset duration.

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