Dual-adsorption refrigerant pressure-reducing gas holder

Abstract

This invention belongs to the field of mixed working fluid cryogenic refrigeration technology, and particularly relates to a dual-adsorption refrigerant pressure-reducing gas storage tank, including a vertical cylindrical main body tank, a top flange cover, a filter assembly, and an internal adsorption assembly. The adsorption assembly includes a three-stage gradient pore size adsorption layer and a surrounding stainless steel mesh grid, which are used to intercept large molecules, medium molecules, and deeply adsorb small molecules of refrigerant, respectively. The outer wall fins of the main body tank dissipate heat, and the bottom exhaust pipe is heated to achieve bidirectional temperature control. The top flange cover integrates a multi-functional interface and is sealed to the tank body. The filter assembly pre-treats the incoming gas. The entire structure realizes the staged adsorption, temperature control optimization, shutdown pressure reduction, and desorption reuse of mixed working fluid gas, significantly reducing the system static pressure, reducing the compressor startup load, and improving operational stability.

Description

Technical Field

[0001] This invention belongs to the field of mixed working fluid cryogenic refrigeration technology, and particularly relates to a double-adsorption refrigerant depressurization storage tank. Specifically, it relates to a compact storage tank that uses MOFs materials and other materials to achieve refrigerant depressurization storage, and is particularly suitable for storing mixed refrigerants in refrigeration cycle systems using methane mixed working fluid. Background Technology

[0002] In cryogenic refrigeration and mixed-refrigerant refrigeration systems, refrigerant storage and system pressure regulation are critical factors affecting system operational stability, compressor start-up reliability, and overall safety. Especially in fields such as natural gas liquefaction, cryogenic treatment, cryogenic cold chain, and aerospace, mixed-refrigerant refrigeration systems using light hydrocarbons such as methane and ethane are widely used due to their high refrigeration efficiency and wide temperature range adaptability. These systems typically use a compressor to drive refrigerant circulation for heat exchange. When the compressor stops, the system circulation is interrupted, and the refrigerant, originally in a liquid or gas-liquid mixture state, gradually vaporizes under the influence of ambient temperature, causing a rapid increase in the system's internal static pressure. This significantly increases the starting load and starting current of the compressor upon restart, and in severe cases, may even prevent the compressor from starting normally or cause mechanical damage. Therefore, existing refrigeration systems are usually equipped with gas storage devices to temporarily store and buffer the gaseous refrigerant during shutdown, reducing the system static pressure and improving the compressor's restart performance.

[0003] Existing refrigerant storage devices mostly adopt metal pressure vessel structures, which mainly rely on the internal space of the tank to accommodate and buffer refrigerant gas. This type of storage tank has a relatively simple structure, usually consisting of a cylindrical tank, flange interface, and connecting pipelines. Under normal operating conditions, it can meet basic gas storage requirements. However, since it is essentially a passive volumetric storage method, its actual storage capacity for gaseous refrigerant under standard STP conditions (temperature 0℃ (273.15K), pressure 1 standard atmosphere 101.325kPa) is limited. When the refrigerant charge in the system is large or the vaporization rate is high after shutdown, it is often necessary to increase the volume of the storage tank to meet the pressure buffering requirements. This not only increases the overall system volume and manufacturing cost but also limits the application of the equipment in space-constrained environments. At the same time, traditional cavity-type storage structures lack the ability to actively adsorb refrigerant gas, and cannot effectively reduce the static pressure of the mixed working fluid system after shutdown, causing the compressor to be in a high-load start-up state for a long time, which in turn affects the system's operational stability and the compressor's service life.

[0004] With the development of adsorption gas storage technology, porous adsorption materials have been gradually applied in the field of gas storage. Among them, materials such as activated carbon and molecular sieves, due to their certain pore structure and specific surface area, have been tried to enhance the gas storage capacity of refrigerants. By filling the inside of the gas storage tank with porous materials, the adsorption capacity of gaseous refrigerants is increased, thereby reducing the system pressure after shutdown. However, the pore size distribution of traditional adsorption materials is relatively simple, and the adsorption capacity is limited. They are not good at adsorbing light small molecule refrigerants. Moreover, during long-term operation, the adsorption efficiency is prone to decline due to impurity deposition, pore blockage, or adsorption heat accumulation, making it difficult to meet the application requirements of cryogenic mixed working fluid refrigeration systems for high-capacity, high-selectivity, and high-stability gas storage.

[0005] In recent years, metal-organic frameworks (MOFs) have attracted widespread attention in the field of gas adsorption and storage due to their ultra-high specific surface area, regular pore structure, and tunable pore size. They exhibit high adsorption capacity for small molecule gases such as methane. Some studies have begun to explore the use of MOFs in refrigerant storage devices to improve gas storage density and system depressurization capacity. However, the application of MOFs in gas storage devices in current technologies is mostly limited to single-layer filling structures, lacking adaptive designs for the differences in mixed working fluid components. Especially for mixed working fluids such as methane and ethane, which have large differences in molecular size, boiling point, and adsorption characteristics, a single adsorbent material cannot simultaneously meet the adsorption needs of different components. Heavy components tend to preferentially occupy the adsorption channels and cause blockage, making it difficult for light components to continue to enter the material for effective adsorption. This leads to a decrease in overall adsorption efficiency, and the static pressure after system shutdown is still difficult to reduce to the ideal range.

[0006] In methane-ethane mixed refrigerant refrigeration systems, methane, as a light component, has characteristics such as small molecular size, fast diffusion rate, and difficulty in liquefaction at room temperature. After shutdown, it easily forms a high-pressure gas phase environment. Meanwhile, heavy components such as ethane are more easily preferentially adsorbed by traditional adsorption materials. Due to the significant differences in molecular dynamic diameters and adsorption competition effects between different components, existing gas storage devices generally lack structural designs for graded adsorption and selective capture of different components. It is difficult to achieve synergistic and efficient adsorption of multi-component mixed refrigerants within a limited volume. Although some existing technologies increase the gas storage capacity by increasing the amount of adsorption material, this leads to problems such as increased gas flow resistance, decreased heat transfer efficiency, and uneven adsorbent utilization, making it impossible to balance adsorption efficiency and system operational stability.

[0007] Furthermore, refrigerant gas adsorption is usually accompanied by significant heat release, while the desorption stage requires external heat to promote the release of refrigerant gas from the adsorbent. Temperature changes in the adsorbent material directly affect its adsorption equilibrium and gas storage performance. However, existing gas storage devices generally lack targeted design in terms of thermal management. Traditional tanks mostly adopt ordinary smooth cylindrical structures with weak overall heat exchange capacity, making it difficult to dissipate adsorption heat to the outside in time. This can easily cause excessive local temperature rise, which inhibits adsorption capacity. At the same time, the contact thermal resistance between the internal support structure and the tank body of some gas storage devices is large, further affecting heat transfer efficiency. In the desorption stage, it is difficult to achieve rapid and effective heat input, resulting in reduced utilization of adsorbent material and slower cycle response speed.

[0008] Therefore, there is an urgent need for a refrigerant depressurization and storage device that can adapt to the characteristics of mixed working fluid components, has graded selective adsorption capabilities, and takes into account thermal management performance, in order to meet the application requirements of modern cryogenic refrigeration systems for efficient, safe, and stable operation. Summary of the Invention

[0009] This invention aims to solve at least one of the above-mentioned technical problems by disclosing a dual-adsorption refrigerant pressure-reducing gas storage tank, including a three-stage gradient pore size adsorption layer, finned heat dissipation and bottom exhaust pipe heating structure, to achieve graded selective adsorption and deep storage of components with different molecular sizes, reduce shutdown pressure, improve compressor restart reliability, and at the same time ensure temperature balance under adsorption and desorption conditions through thermal management structure, thereby improving overall gas storage efficiency and system operation stability.

[0010] The technical solution of the present invention is as follows:

[0011] A dual-adsorption refrigerant pressure-reducing gas storage tank, comprising:

[0012] The main tank body is a pressure vessel structure with an internal gas storage chamber;

[0013] A top flange cover is disposed on the top of the main tank body and is sealed to the main tank body.

[0014] A filter assembly, located above the top flange cover and communicating with the interior of the main tank, is used to filter the refrigerant gas entering the main tank.

[0015] An adsorption component is disposed inside the main tank and connected to the filter component, and is used to perform gradient adsorption of different components in the mixed working fluid.

[0016] The adsorption assembly includes an adsorption tube extending axially along the main tank and a stainless steel mesh grid surrounding the outside of the adsorption tube. The adsorption tube is provided with a porous partition, which divides the internal space of the adsorption tube into a first adsorption layer and a second adsorption layer arranged sequentially along the airflow direction. A third adsorption layer is formed between the stainless steel mesh grid and the inner wall of the main tank. The adsorption pore sizes of the first adsorption layer, the second adsorption layer and the third adsorption layer decrease sequentially along the airflow direction, and the third adsorption layer is filled with a metal-organic framework material.

[0017] Furthermore, the filter assembly includes a filter housing, a filter element, and a fixing spring for pressing the filter element. The filter housing is wrapped around the outside of the filter element and the fixing spring, and has adapters at its upper and lower ends. The upper adapter is connected to the air inlet pipe of the refrigeration system, and the lower adapter is connected to the adsorption assembly.

[0018] Furthermore, the inner bottom surface and the top flange cover of the main tank are respectively provided with connecting parts, and the upper and lower ends of the stainless steel mesh grid are respectively fixed to the corresponding connecting parts.

[0019] Furthermore, the connecting part includes a slot, and the upper and lower ends of the stainless steel mesh grid are respectively inserted into the corresponding slots and can be detachably fixed by the second connecting screw, and a metal contact interface is formed between the outer wall of the end of the stainless steel mesh grid and the inner wall of the slot of the connecting part.

[0020] Furthermore, the top flange cover is provided with multiple external interfaces, including a central external interface and an inner ring external interface located at the center. The central external interface is located at the center of the top flange cover. The adapter at the lower end of the filter assembly is connected to the adsorption assembly at the central external interface. The inner ring external interface includes at least an exhaust interface, a safety interface, and a pressure and temperature measurement interface, which are used for gas discharge, overpressure protection, and status monitoring, respectively.

[0021] Furthermore, the main tank body is a vertical cylindrical structure, and the top flange cover is sealed and fixedly connected to the main tank body by a plurality of first connecting screws.

[0022] Furthermore, the plurality of first connecting screws are evenly distributed along the circumference of the top flange cover, and the top flange cover is provided with an outer ring outer interface corresponding to each of the plurality of first connecting screws. The outer ring outer interface and the inner ring outer interface for installing the exhaust interface, safety interface and pressure and temperature measurement interface are arranged in concentric circles on the top flange cover.

[0023] Furthermore, the outer wall of the main tank is provided with a rib structure.

[0024] Furthermore, a compressor exhaust pipe is wound around the bottom outer side of the main tank body. The exhaust pipe has a first air inlet and a first air outlet, which are used to heat the tank body using the heat from the compressor exhaust.

[0025] Further, the first adsorption layer is filled with one or more of SBA-15 mesoporous molecular sieve, NU-1000 or MIL-101 metal-organic framework materials, the second adsorption layer is filled with one or more of activated carbon, 13X molecular sieve, Mn-PNMI or ZIF-7 metal-organic framework materials, and the third adsorption layer is filled with one or more of MOF-5, CD-MOF-S1, ZIF-8, MOF-700, MIL-53, MOF-702, MOF-703, MOF-701, PCN-14, HKUST-1, Mg-MOF-74, Co-MOF-74 or Ni-MOF-74 materials.

[0026] Compared with existing technologies, the dual-adsorption refrigerant pressure-reducing gas storage tank of the present invention has the following advantages:

[0027] 1. This application constructs a three-level gradient adsorption layer from macropores to micropores on the inner and outer sides of the adsorption tube, enabling components of different molecular sizes in the mixed working fluid to enter the adsorption region with matching pore sizes respectively. This achieves preferential interception of large molecular weight components, selective adsorption of medium molecules, and deep capture of small molecules, avoiding pore blockage and adsorption competition, ensuring that the adsorption efficiency of each component is maximized and a complete gradient adsorption chain is formed, thereby reducing the static pressure inside the gas storage tank and the system during shutdown.

[0028] 2. This application combines the outer wall ribs of the main tank body with the bottom exhaust pipe to form a two-way temperature control system that combines heat dissipation during the adsorption stage and heating during the desorption stage. This system enables the rapid dissipation of adsorption heat during the adsorption process, prevents local overheating from inhibiting the adsorption capacity, and utilizes the waste heat of the compressor to heat the adsorbent material during the desorption stage, so that the adsorbed refrigerant molecules can be desorbed smoothly. This ensures that the adsorption and desorption cycles are fast, efficient, and uniform, thereby improving the overall response speed and long-term cycle stability of the gas storage tank.

[0029] 3. The dual-adsorption refrigerant pressure-reducing gas storage tank described in this application has a compact structure. The top flange cover is sealed to the tank body and integrates a multi-functional interface. The filter component effectively removes gas impurities, and the stainless steel mesh grid stabilizes the MOFs material and creates physical interception, allowing each adsorption layer to fully contact the gas. The overall design achieves smooth airflow, reasonable temperature control, high adsorption capacity, good maintainability, and improved reliability of compressor restart. It is suitable for high-efficiency pressure-reducing gas storage applications in methane-ethane mixed working fluid cryogenic refrigeration systems. Attached Figure Description

[0030] Figure 1 This is a side view of the dual-adsorption refrigerant pressure-reducing gas storage tank described in an embodiment of the present invention;

[0031] Figure 2 This is a front view of the dual-adsorption refrigerant pressure-reducing gas storage tank described in an embodiment of the present invention;

[0032] Figure 3 This is a side sectional view of the dual-adsorption refrigerant pressure-reducing gas storage tank described in an embodiment of the present invention;

[0033] Figure 4 This is a side top sectional view of the dual-adsorption refrigerant pressure-reducing gas storage tank described in an embodiment of the present invention;

[0034] Figure 5 This is a top view of the dual-adsorption refrigerant pressure-reducing storage tank described in an embodiment of the present invention;

[0035] Figure 6 This is a schematic diagram of the adsorption layers in the upper and lower inner cavities of the adsorption tube in the dual adsorption refrigerant pressure-reducing storage tank described in this embodiment of the invention;

[0036] Figure 7 This is a schematic diagram of the stepwise adsorption process during the flow of the mixed refrigerant in an embodiment of the present invention;

[0037] Figure 8 This is a cross-sectional schematic diagram of the gradient interception and staged adsorption of the dual adsorption refrigerant depressurization storage tank in an embodiment of the present invention;

[0038] Figure 9 This is a schematic diagram of the compressor exhaust pipe disc at the bottom of the main tank in an embodiment of the present invention;

[0039] Figure 10 This is a bottom view of the compressor exhaust pipe disc at the bottom of the main tank in an embodiment of the present invention;

[0040] Figure 11 This is a flowchart of a small refrigeration system in an embodiment of the present invention;

[0041] Figure 12 This is a comparison table of the total number of gas moles and static pressure between the control group and the experimental group in this embodiment of the invention;

[0042] The markings in the diagram are as follows:

[0043] 1. Adapter; 2. Filter housing; 3. External interface; 4. First connecting screw; 5. Top flange cover; 6. Main tank; 7. Stainless steel mesh grille; 8. Connecting part; 9. Fixing spring; 10. Filter element; 11. Adsorption tube; 12. Second connecting screw; 13. Porous partition; 14. Filter assembly; 15. Adsorption assembly; 30. Mixed working fluid; 31. Upper inner cavity adsorption layer; 32. Lower inner cavity adsorption layer; 33. Suction layer; 34. First adsorption layer; 35. Second adsorption layer; 36. Third adsorption layer; 50. Exhaust pipe; 51. First air inlet; 52. First air outlet; 100. Compressor; 101. Condenser; 102. Throttling valve; 103. Evaporator; 104. Gas storage tank. Detailed Implementation

[0044] The technical solutions of the embodiments of this application will be clearly described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application are within the scope of protection of this application.

[0045] It should be noted that all directional and positional terms used in this invention, such as "up," "down," "left," "right," "front," "back," "vertical," "horizontal," "inner," "outer," "top," "lower," "lateral," "longitudinal," and "center," are only used to explain the relative positional relationships and connections between components in a specific state (as shown in the accompanying drawings). They are merely for the convenience of describing the invention and do not require the invention to be constructed and operated in a specific orientation; therefore, they should not be construed as limitations on the invention. Furthermore, descriptions involving "first," "second," etc., are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated.

[0046] In the description of this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0047] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0048] like Figures 1-10 As shown, this application discloses a dual-adsorption refrigerant pressure-reducing gas storage tank, comprising:

[0049] The main tank 6 is a pressure vessel structure with an internal gas storage chamber, which is used to provide space for the storage and adsorption of refrigerant gas;

[0050] The top flange cover 5 is located on the top of the main tank 6 and is sealed to the main tank 6 to form a closed gas storage structure and to serve as the installation connection part of the filter assembly 14 and the adsorption assembly 15.

[0051] The filter assembly 14 is disposed above the top flange cover 5 and communicates with the interior of the main tank 6, and is used to filter the refrigerant gas entering the main tank 6.

[0052] Adsorption component 15 is disposed inside the main tank 6 and communicates with the filter component 14, and is used to perform gradient adsorption of different components in the mixed working medium 30.

[0053] The adsorption assembly 15 includes an adsorption tube 11 extending axially along the main tank 6 and a stainless steel mesh 7 surrounding the outside of the adsorption tube 11. The adsorption tube 11 is provided with a porous partition 13, which divides the internal space of the adsorption tube 11 into an upper inner cavity adsorption layer 31 and a lower inner cavity adsorption layer 32. The upper inner cavity adsorption layer 31 is a first adsorption layer 34, and the lower inner cavity adsorption layer 32 is a second adsorption layer 35. A third adsorption layer 36 is formed between the stainless steel mesh 7 and the inner wall of the main tank 6. The adsorption molecule size of the multiple adsorption layers decreases sequentially along the airflow direction. The third adsorption layer 36 is filled with MOF material to form a hierarchical adsorption structure for different molecular size components of the mixed working fluid 30.

[0054] The dual-adsorption refrigerant pressure-reducing gas storage tank disclosed in this application constructs a layered mixed working fluid adsorption and storage structure within a limited volume through the synergistic structural combination of the main tank body 6, top flange cover 5, filter assembly 14, and adsorption assembly 15. The main tank body 6 serves as the overall pressure-bearing and gas storage foundation structure, providing stable installation space for the internal multi-stage adsorption zones. The top flange cover 5 is sealed to the main tank body 6, maintaining a stable and airtight state of the overall gas storage space, thereby ensuring that the refrigerant gas is not easily leaked during adsorption and storage. Simultaneously, the top flange cover 5 serves as a safety feature for both the filter assembly 14 and the adsorption assembly 15. The supporting structure makes the overall layout more concentrated and compact. The filter component 14 is located at the front end of the gas inlet path, allowing the refrigerant gas to undergo pretreatment of oil mist, particulate matter, and other impurities before entering the adsorption area. This effectively avoids the problems of pore blockage, decreased adsorption efficiency, and shortened material life caused by impurities directly entering the adsorption layer, thus ensuring the long-term stable operation of the subsequent adsorption structure. The adsorption component 15 adopts a layout combining the central adsorption tube 11 with the peripheral small-diameter adsorption area. The porous partition 13 divides the interior of the adsorption tube 11 into two independent yet interconnected adsorption areas. The first adsorption layer 34 preferentially intercepts heavy components with larger molecular sizes, while the lower second adsorption layer 35 continues to adsorb medium-sized components. The small-pore adsorption region enclosed by the stainless steel mesh 7 is used to adsorb light components such as methane. Through this gradient pore size layout from macropores to mesopores to micropores, refrigerant components of different molecular sizes entering the adsorption tube 11 and the getter layer 33 can all enter the adsorption region matching their size and be selectively captured. This avoids the problem of large molecules preferentially blocking the pores and small molecules being unable to enter the internal adsorption area, which is common in traditional single-pore adsorption structures. The stainless steel mesh grid 7 not only stabilizes and limits the outer MOFs material, preventing it from shifting, accumulating, or collapsing during airflow impact, but also maintains a relatively uniform diffusion state of airflow in the outer adsorption area. This allows light component gases to fully contact the MOFs material and improves the overall adsorption utilization rate. The overall structure adopts a longitudinal series and surrounding combination layout, which ensures smooth airflow while enabling multiple adsorption areas to be efficiently integrated in a limited space. This balances adsorption capacity, gas flow efficiency, and structural compactness, meeting the requirements for rapid depressurization and stable storage of methane and ethane mixed working fluids during shutdown.

[0055] In the operation of the dual-adsorption refrigerant pressure-reducing gas storage tank disclosed in this application, the refrigerant gas first enters the filter assembly 14 from the top. In the filter assembly 14, the filter element structure filters out lubricating oil mist, dust particles, and other impurities entrained in the gas, thus keeping the gas entering the subsequent adsorption zone relatively clean. The filtered refrigerant gas continues to flow downwards along the connecting path into the adsorption assembly 15 inside the main tank 6. The gas first enters the adsorption tube 11 arranged axially along the main tank 6. During its downward flow within the adsorption tube 11, the gas first passes through the upper first adsorption layer 34. Due to the large pore size of the material in this region, it can preferentially adsorb and retain the largest molecular components in the mixed working fluid 30, confining the large molecules within the corresponding area. The remaining gas then continues downwards to the second adsorption layer 35. The adsorption material in the second adsorption layer 35 further selectively adsorbs the medium-sized components, thus completing the second stage of graded adsorption treatment. After the two adsorption treatments, the gas is completely purified. Unadsorbed small-molecule light components continue to diffuse outwards, entering the third adsorption layer 36 formed between the inner wall of the main tank 6 and the stainless steel mesh 7 through the stainless steel mesh 7 surrounding the adsorption tube 11. The MOFs material filled in this area has a uniform microporous structure with small pore size, which can further deeply adsorb small-molecule gases such as methane. This allows different components in the mixed working fluid 30 to be adsorbed and stored in stages according to molecular size. During the compressor shutdown stage, a large amount of vaporized refrigerant gas is gradually adsorbed and fixed, thereby reducing the static pressure inside the gas storage tank and the entire refrigeration system, and avoiding the continuous increase in internal system pressure that would affect subsequent startup. When the system restarts, external heat or system heat is gradually transferred to the inside of the gas storage tank, causing the temperature of the adsorption material to rise. The refrigerant molecules adsorbed in different pore size areas are gradually desorbed and released, and re-enter the refrigeration cycle system to participate in the cycle operation. Through the continuous process of filtration, gradient adsorption, pressure reduction, and thermal desorption and reuse, the mixed working fluid 30 refrigerant is stably switched and recycled between the shutdown and startup stages.

[0056] The dual-adsorption refrigerant pressure-reducing gas storage tank disclosed in this application combines a filtration structure with a gradient adsorption structure, enabling the refrigerant gas to undergo impurity purification before entering the adsorption zone. The overall structure is compact, with clear layers and well-defined functional zones. It can effectively reduce the static pressure of the mixed refrigerant refrigeration system after shutdown, reduce the starting load when the compressor restarts, and enable repeated desorption and reuse of refrigerant gas, thereby improving refrigerant utilization efficiency. It is particularly suitable for pressure-reducing gas storage applications in low-temperature refrigeration systems with mixed refrigerants such as methane and ethane.

[0057] In some examples of this application, the filter assembly 14 includes a filter housing 2, a filter element 10, and a fixing spring 9 for pressing and fixing the filter element 10. The filter housing 2 is wrapped around the outside of the filter element 10 and the fixing spring 9. A connector 1 is provided at each of the upper and lower ends of the filter housing 2. The upper connector 1 is connected to the air inlet pipe of the refrigeration system, and the lower connector 1 is connected to the inlet of the adsorption assembly 15. This application employs a wrap-around structure in the filter housing 2 to integrate the filter element 10 and the fixing spring 9, forming a fully enclosed filter assembly 14. The specific fixing structure is a relatively conventional technique and will not be elaborated upon further. The filter housing 2 not only houses and positions the filter element 10 and the fixing spring 9 but also forms a completely closed flow channel, guiding gas along a predetermined path through the filter element 10. The filter element 10 physically traps oil mist, fine particles, and impurities in the gas on its surface. The fixing spring 9 continuously applies pressure to ensure tight contact between the filter element 10 and the filter housing 2, preventing gas from flowing around the filter element through gaps. Furthermore, the filter assembly 14 connects to the air intake pipe of the refrigeration system via two adapters 1. The filter element 10 is reliably connected to the adsorption assembly 15. The upper adapter 1 serves as the refrigerant gas inlet, ensuring smooth gas entry into the filter assembly 14. The lower adapter 1 serves as the outlet, directly connected to the adsorption assembly 15, ensuring the filtered gas can smoothly enter the subsequent adsorption area. The filter element 10 is continuously subjected to uniform pressure by the fixing spring 9, maintaining a stable and tightly fitted state under airflow impact. This prevents local bypass leakage or decreased filtration efficiency due to loosening or wrinkles. The overall structure is simple and compact, facilitating pre-assembly, installation, disassembly, and filter element maintenance or replacement. It provides a stable and clean gas environment for the adsorption assembly without adding complex structures, effectively extending the lifespan of the adsorption material and maintaining the long-term stable operation of the gas storage tank. In some examples of this application, the filter element 10 uses metal or polymer porous materials, with a flow rate ≥ 50 L / min, pressure drop ≤ 50 kPa, and lifespan ≥ 3000 hours.

[0058] In some examples of this application, the inner bottom surface of the main tank 6 and the bottom surface of the top flange cover 5 are both provided with connecting parts 8, and the upper and lower ends of the stainless steel mesh grating 7 are respectively fixed to the corresponding connecting parts 8. This application provides connecting parts 8 as corresponding installation points on the inner bottom surface of the main tank 6 and the bottom surface of the top flange cover 5, so that the upper end of the stainless steel mesh grating 7 cooperates with the connecting part 8 on the bottom surface of the top flange cover 5, and the lower end cooperates with the connecting part 8 on the inner bottom surface of the main tank 6. Through the double-end positioning, the stainless steel mesh grating 7 is accurately positioned and stably fixed in the tank. The entire mesh grating forms a stable ring structure inside the tank, avoiding shaking, displacement or falling off during airflow impact, refrigeration system pressure fluctuations and gas storage tank transportation. The connecting parts 8 can be in the form of recessed grooves, raised positioning steps or threaded fixing seats, etc., to provide stable support and precise positioning.

[0059] Preferably, the connecting part 8 includes a slot, and the upper and lower ends of the stainless steel mesh grid 7 are respectively inserted into the slot of the connecting part 8 and then detachably fixed by the second connecting screw 12. This application uses a combination of slots and second connecting screws 12 for fixing, allowing the stainless steel mesh grid 7 to be quickly positioned and radially constrained during installation by first inserting into the slot, and then firmly fixed by tightening the screws. This ensures that the mesh grid remains vertically centered and stable under gas flow, pressure fluctuations, and handling vibrations. The MOFs material in the annular small-aperture adsorption area can thus be uniformly filled and maintain a stable distribution. The slot provides a large area of ​​contact and constraint, while the screws provide axial locking force. Together, they achieve a stable and detachable fixing effect. This structure does not require additional gas storage or adsorption space, does not affect gas flow or adsorption efficiency, and is easy to install and disassemble with intuitive operation. Simultaneously, it maintains the integrity and stability of the staged adsorption system during long-term operation, providing a reliable structural guarantee for the efficient and safe operation of the gas storage tank. Preferably, the slot of the connecting part 8 is provided with four second connecting screws 12, which are cross screws. The cross screws are evenly distributed along the circumference of the slot and are used to lock and fix the end of the stainless steel mesh grid 7 inserted into the slot. By tightening the cross screws, a tight metal contact interface can be formed between the outer wall of the end of the stainless steel mesh grid 7 and the inner wall of the slot of the connecting part 8, thereby effectively eliminating the additional contact thermal resistance caused by the fit gap or loose assembly. When it is necessary to remove the additional heat from the gas storage tank, the heat can be quickly transferred to the stainless steel mesh grid 7 through the connecting part 8 and the cross screws, and then evenly conducted by the stainless steel mesh grid 7 to the MOFs material filled between it and the inner wall of the main tank 6, which improves the overall heat transfer efficiency and ensures the heating uniformity and response speed of the desorption process.

[0060] In some examples of this application, the top flange cover 5 is provided with multiple external interfaces 3, and the multiple external interfaces 3 include at least a central external interface and an inner ring external interface. The central external interface is located at the center of the top flange cover 5. The adapter 1 at the lower end of the filter assembly 14 is connected to the adsorption assembly 15 at the central external interface. The inner ring external interface includes at least an exhaust interface, a safety interface, and a pressure and temperature measurement interface, which are used to realize the orderly discharge of refrigerant gas, overpressure protection of the tank, and real-time pressure and temperature status monitoring, respectively. This application provides a central external interface at the center of the top flange cover 5, which is connected and fixed to the adapter 1 at the lower end of the filter assembly 14. This allows the refrigerant gas flowing from the filter assembly 14 to enter the adsorption tube 11 of the adsorption assembly 15 vertically downwards along the axis of the gas storage tank, reducing gas flow resistance. The inner ring external interface is used to realize the orderly discharge of refrigerant gas, overpressure protection of the tank, and real-time pressure and temperature status monitoring, respectively. This integrates the gas output, safety protection, and status monitoring functions of the gas storage tank onto the top flange cover 5. The exhaust interface ensures smooth output of refrigerant during desorption and reflux. The safety interface, connected to a safety valve or rupture disc, automatically releases pressure to prevent tank damage when the tank pressure rises abnormally. The pressure and temperature measurement interface is used to install sensors to collect real-time pressure and temperature data inside the tank. The three interfaces are compactly arranged and independent of each other. The compact layout and clear functions of each interface allow them to work independently without interference, facilitating standardized connection with external pipelines, safety devices, and monitoring instruments.

[0061] In some examples of this application, the exhaust port, safety port, and pressure and temperature measurement port are arranged on a concentric circle at the center of the top flange cover 5. Preferably, the exhaust port, safety port, and pressure and temperature measurement port are evenly arranged along the center point of the top flange cover 5, serving as the outer interface of the inner ring on the top flange cover 5. This makes the pipeline connection more regular and orderly, the pressure and temperature measurement point closer to the center area of ​​the tank, resulting in more accurate data collection, the safety port responding quickly in case of pressure abnormalities, and the exhaust port outputting smoothly during the desorption and reflux stage. This application, through the structural design of central air intake combined with the inner ring annular interface distribution, enables the orderly realization of gas flow, exhaust, safety protection, and pressure and temperature measurement functions without interference. The overall structure is compact and reliable, easy to assemble, and improves the operational stability and control accuracy of the gas storage tank.

[0062] In some examples of this application, the main tank 6 is an overall vertical cylindrical structure, and the top flange cover 5 is sealed and fixedly connected to the main tank 6 by multiple first connecting screws 4. By designing the main tank 6 as a vertical cylindrical structure, this application allows the gas inside the gas storage tank to flow axially from top to bottom, avoiding the formation of local dead zones and eddies. This allows the adsorbent material to be neatly filled in each layered area, ensuring the uniformity and adsorption efficiency of each pore size adsorption layer. At the same time, the cylindrical tank is subjected to balanced forces, and can withstand higher pressures without local stress concentration under alternating high and low pressure operation, improving the overall stability and service life of the tank. The top flange cover 5 is sealed and fixed to the tank by multiple first connecting screws 4, and a high-reliability seal is achieved through sealing gaskets or precision metal fittings. At the same time, the top flange cover 5 can be easily disassembled when needed to achieve maintenance of the internal adsorption component 15 and replacement of the adsorbent material. The screw connection structure is simple and robust, with low processing and manufacturing difficulty, and quick assembly and disassembly. The overall structure takes into account pressure bearing capacity, sealing performance, practicality, and economy, and can stably adapt to the pressure reduction and gas storage requirements of various mixed working fluid refrigeration systems. In the example of this application, the top flange cover 5 is sealed and fixed to the main tank body 6 by six first connecting screws 4.

[0063] Preferably, the plurality of first connecting screws 4 are evenly distributed along the circumference of the top flange cover 5. The top flange cover 5 is provided with an outer ring interface that corresponds one-to-one with the plurality of first connecting screws 4 to achieve uniform locking and sealing with the main tank body 6. At the same time, the outer ring interface and the inner ring interface for installing the exhaust interface, safety interface and pressure and temperature measurement interface form a concentric circle layout on the top flange cover 5, so that the top flange cover 5 is subjected to balanced force when bearing the screw preload and the load of each interface pipeline, ensuring the reliability of the seal. In some examples of this application, the material of each outer interface of the top flange cover 5 is stainless steel or copper alloy, the sealing pressure rating is ≥25 bar, and the interface is connected to the gas storage pipeline using standard flanges or threads to ensure smooth gas flow and safety and reliability.

[0064] In some examples of this application, the outer wall of the main tank 6 is provided with a rib structure. This application adds a rib structure to the outer wall of the main tank 6. The ribs can be strip-shaped or wing-shaped protrusions, uniformly arranged along the axial direction, circumferential direction, or a combination of both, forming a continuous or stably welded integrated structure. Preferably, the ribs are made of copper or aluminum alloy with a thermal conductivity ≥150 W / m·K and a rib spacing of 10~20 mm. This increases the outer surface area of ​​the tank, enhances heat conduction and heat dissipation efficiency, and allows the heat released during adsorption to be quickly transferred from the inner wall of the tank to the outer wall. Then, the heat is dissipated through natural convection and radiation with the surrounding air via the rib surface, achieving passive and efficient thermal management. The presence of the ribs keeps the tank at a uniform low temperature, avoiding local overheating that could reduce adsorption capacity. At the same time, the rib structure does not occupy the internal adsorption space or affect the pressure-bearing capacity of the tank. Instead, it enhances the rigidity and pressure resistance of the tank. The entire design requires no additional power drive, is simple and reliable in structure, and is easy to process and assemble. It provides a stable and ideal working temperature environment for MOFs materials and other adsorption materials, ensuring high efficiency and long-term operational stability of the gas storage tank during the depressurization adsorption process.

[0065] In some examples of this application, a smooth surface area is reserved at the bottom of the main tank 6, and a compressor exhaust pipe 50 is wound around the outside of the smooth surface area. The exhaust pipe 50 is provided with a first air inlet 51 and a first air outlet 52, which are used to heat the tank and the internal adsorbent material by using the heat from the compressor exhaust. This application further specifies that the rib structure on the outer wall of the main tank 6 is a non-full-height structure, that is, the ribs do not extend from the top to the bottom of the tank, but a smooth cylindrical surface is reserved at the bottom. This smooth surface is used to tightly wrap the exhaust pipe 50 of the compressor, so that the exhaust pipe 50 makes full contact with the outer wall of the tank. The exhaust pipe 50 is provided with a first air inlet 51 and a first air outlet 52 for connecting with the compressor exhaust circuit. The high-temperature exhaust of the compressor itself provides the heat energy required for desorption. The non-full-height ribs continue to maintain efficient heat dissipation function at the top, realizing bidirectional temperature control of heat dissipation in the adsorption stage and heating in the desorption stage. The exhaust pipe 50 can be extended by single-layer or multi-layer winding to improve the uniform distribution of heat. The entire design does not occupy the internal space of the tank, and temperature control management can be achieved without additional heating devices. The structure is compact and reliable, and the processing and assembly are simple. It ensures that the gas storage tank can maintain a suitable temperature under both adsorption and desorption conditions, thereby improving the overall efficiency and operational stability of the gas storage tank.

[0066] In some examples of this application, the first adsorption layer 34 is filled with one or more of SBA-15 mesoporous molecular sieve, NU-1000 or MIL-101 MOFs materials for preferential adsorption of heavy components with the largest molecular diameter; the second adsorption layer 35 is filled with one or more of activated carbon, 13X molecular sieve, Mn-PNMI or ZIF-7 MOFs materials for selective adsorption of medium molecular diameter components; and the third adsorption layer 36 is filled with one or more of MOF-5, CD-MOF-S1, ZIF-8, MOF-700, MIL-53, MOF-702, MOF-703, MOF-701, PCN-14, HKUST-1, Mg-MOF-74, Co-MOF-74 or Ni-MOF-74 for deep adsorption of light components. This application employs precise selection and layered arrangement of materials in a three-stage gradient adsorption layer. The first adsorption layer utilizes SBA-15 mesoporous molecular sieves, NU-1000, or MIL-101 MOFs, which have large pore sizes and regular structures, enabling them to preferentially capture large molecular weight components such as isobutane and prevent them from entering the lower layers and causing blockage. The second adsorption layer utilizes activated carbon, 13X molecular sieves, Mn-PNMI, or ZIF-7. MOF materials with moderate pore size are specifically designed for the efficient adsorption of medium-molecular-weight components such as ethane, ensuring further purification of residual gases. The third adsorption layer consists of a stainless steel mesh cavity surrounding the adsorption tube, filled with small-pore MOF materials, including MOF-5, CD-MOF-S1, ZIF-8, MOF-700, MIL-53, MOF-702, MOF-703, MOF-701, PCN-14, HKUST-1, Mg-MOF-74, Co-MOF-74, or Ni-MOF-74. Their pore sizes are highly matched to the smallest molecules such as methane, enabling efficient adsorption. The system achieves deep adsorption and high-capacity capture of light components. The stainless steel mesh grid 7 not only fixes the material to prevent displacement but also physically intercepts the airflow. The three layers of material form a complete gradient adsorption chain according to molecular size, from largest to smallest. Each layer possesses excellent structural stability, specific surface area, and thermal conductivity. Heat released during adsorption is rapidly dissipated through the tank's ribs. During desorption, the bottom heating structure provides heat, and the increased temperature of each adsorption layer allows the component molecules to gain energy for desorption and return to the circulation system. The three layers achieve gradient adsorption and stepwise desorption of the gas according to molecular size, ensuring sufficient adsorption and efficient recovery of different molecules. It should be noted that the specific pore size selection of the three adsorption layers and their matching relationship with the molecular diameters of the components in the mixed working fluid 30, as well as the specific parameters such as the adsorption capacity of each adsorption material under different temperature and pressure conditions, are all matters that a person skilled in the art can determine based on practical application needs through conventional experiments or experience after reading the disclosure of this application. For example, the pore size range of the material filling the first adsorption layer 34 is approximately 2~10 nm, and the specific surface area is ≥1000 m². 2 / g, adsorption capacity ≥0.005~0.006 mol / g; the second adsorption layer has a pore size range of approximately 0.4~2nm and a specific surface area ≥800 m² / g. 2 / g, adsorption capacity ≥0.004~0.005 mol / g; the third adsorption layer 36 has a pore size range of approximately 0.3~1.5nm and a specific surface area ≥1500 m² / g. 2 / g, with an adsorption capacity ≥0.015~0.02 mol / g, can effectively match the kinetic diameters of methane, ethane and isobutane, ensuring the fractional adsorption effect, which will not be elaborated here.

[0067] The working process of this embodiment is as follows:

[0068] When the compressor stops and the system stops running, the mixed refrigerant gas from the evaporator enters the gas storage tank through the upper adapter 1. The gas first flows into the filter assembly 14 located above the top flange cover 5 and undergoes preliminary filtration through the filter element 10 to effectively remove lubricating oil mist and large particulate impurities entrained in the gas.

[0069] After filtration, the gas flows downwards through the lower connector 1 into the adsorption assembly 15 inside the main tank 6. The gas first flows through the adsorption tube 11 vertically positioned in the center of the tank, passing sequentially through the upper inner cavity adsorption layer 31, the porous partition 13, and the lower inner cavity adsorption layer 32. Utilizing the pore size difference between the upper and lower adsorption materials, the upper first adsorption layer 34 preferentially captures the largest molecular diameter heavy components, while the lower second adsorption layer 35 captures the medium-sized components with the next largest molecular diameter. This achieves stratified gradient interception and preliminary adsorption and depressurization of the heavy components in the mixed working fluid 30. Subsequently, the preliminarily purified light component gas passes through the stainless steel mesh 7 and enters the annular filling area between the inner wall of the main tank 6 and the stainless steel mesh 7, making full contact with the MOFs material with a small pore size structure, i.e., the third adsorption layer 36. The pore size of this MOFs material is highly matched to the molecular dynamics diameter of light components such as methane, enabling it to leverage its high specific surface area advantage for deep adsorption of light components such as methane in the refrigerant. The above-mentioned gradient interception and stratified adsorption process is as follows: Figure 7 , Figure 8 As shown.

[0070] In the above adsorption process, the adsorption reaction is an exothermic process. This application significantly increases the heat dissipation surface area of ​​the tank by setting a rib structure on the outside of the main tank 6. The rib structure effectively dissipates the heat generated by adsorption and the ambient heat by utilizing air convection, thereby achieving passive heat dissipation and cooling. According to the principle of adsorption thermodynamics, a lower temperature is conducive to the adsorption process. This heat dissipation design enhances the adsorption capacity and efficiency of MOFs materials and adsorption materials at all levels, ultimately achieving deep adsorption and depressurized storage of refrigerant gas.

[0071] Once the compressor starts and the system is running normally, the gas storage tank enters the exhaust and desorption phase. At this time, the high-temperature gas discharged by the compressor flows in through the first inlet 51 of the compressor exhaust pipe, passes through the exhaust pipe 50 wrapped around the smooth bottom surface of the main tank 6, and flows out through the first outlet 52. During the flow, the bottom of the main tank 6 is heated. As the temperature inside the tank rises, the MOFs material in the third adsorption layer 36 and the refrigerant molecules adsorbed in each level of the adsorption layer in the adsorption tube 11 gain energy and change from the adsorbed state to the free state to achieve desorption. The desorbed refrigerant gas is discharged through the exhaust valve connected to the external interface 3 under the system pressure difference or the suction action of the compressor, and re-enters the refrigeration cycle system or is collected and utilized.

[0072] The dual-adsorption refrigerant depressurization storage tank disclosed in this application employs a synergistic process combining filters and multiple adsorption. By constructing a three-level gradient pore size adsorption structure within a limited volume, components of different molecular sizes in the mixed working fluid 30 can sequentially enter adsorption regions matching their pore sizes, achieving hierarchical adsorption and storage from macromolecules to small molecules. This avoids macromolecules clogging the pores of small molecules, improving the adsorption efficiency of light components. Simultaneously, the external rib structure of the main tank 6 provides heat dissipation, and the bottom exhaust pipe 50 provides heating, achieving bidirectional temperature control under adsorption and desorption conditions. This ensures the adsorbent material is within the ideal operating temperature range, guaranteeing adsorption efficiency and cycle response speed. This structure utilizes a top flange... The cover 5 is sealed to the tank body and integrates a multi-functional interface, realizing orderly gas flow, smooth exhaust, and centralized layout of safety protection and real-time monitoring functions. It is convenient for installation, maintenance and system connection. The overall structure is compact, pressure-bearing and reliable, and can effectively reduce the static pressure of the system during shutdown, reduce the compressor starting load and prevent mechanical damage. The staged adsorption design of this gas storage tank, combined with the thermal management structure, takes into account the adsorption selectivity, adsorption capacity, temperature control efficiency and long-term stability of multi-component adsorption. It enables mixed working fluids such as methane, ethane and isobutane to operate efficiently, stably and safely during shutdown and startup, improving the operational reliability and gas storage performance of the mixed working fluid cryogenic refrigeration system.

[0073] Example 1

[0074] To further illustrate the effectiveness of this invention in reducing system static pressure, this embodiment uses a small refrigeration system employing a mixture of R50 (methane), R170 (ethane), and R600a (isobutane) as an example. Figure 11As shown, the refrigeration system consists of a compressor 100, a condenser 101, a throttling valve 102, an evaporator 103, and a gas storage tank 104. The gas storage tank 104 is used for depressurizing and storing the dual-adsorption refrigerant described in this invention. Its working process is as follows: the refrigerant is compressed by the compressor 100 and enters the condenser 101 to release heat; then, after being depressurized by the throttling valve 102, it enters the evaporator 103 to absorb heat; finally, it returns to the compressor 100 to complete the cycle. The gas storage tank 104 is connected between the evaporator 103 and the compressor 100 and is used to store the refrigerant when the system is shut down. The molar ratio of the mixed working fluid is 0.39:0.2:0.41, and the total charge is 28 mol. Assuming that after the system stops, the refrigerant is redistributed between the gas receiver 104 and the rest of the system components (condenser 101, evaporator 103 and connecting pipes), the volume of the rest of the refrigeration system except for the gas receiver 104 is 32L, and the total volume of the refrigeration system is 40L. The initial state of the gas receiver 104 is a temperature of 300K (27℃) and a pressure of 15bar.

[0075] To quantify the effect of the present invention, two control groups and an experimental group were set up: control group 1 had no adsorbent material in the gas storage tank 104 (i.e., a traditional empty tank); control group 2 had 400g of a single MOF adsorbent material in the gas storage tank; the experimental group used the dual adsorption refrigerant pressure reduction gas storage tank of the present invention, which was filled with adsorption tubes 11 with graded pore size adaptation structure and MOF material. To address the differences in molecular dynamic diameters among the three components in the mixed working fluid (isobutane > ethane > methane), a gradient pore size stepped interception scheme was designed: the adsorption tube is divided into upper and lower parts. The upper part is filled with 100g of macroporous adsorbent material, which preferentially intercepts isobutane, the component with the largest molecular diameter and the easiest to condense, by utilizing the size sieving effect. The adsorption capacity for isobutane at 300K and 15bar is calculated as 0.006mol / g. The lower part is filled with 100g of mesoporous adsorbent material, which selectively adsorbs ethane, the component with the second largest molecular diameter. The adsorption capacity for ethane at the same conditions is calculated as 0.005mol / g. The outermost part is filled with 200g of small-pore MOF adsorbent material, which is specifically used to adsorb methane, the component with the smallest molecular diameter. The adsorption capacity for methane at 300K and 15bar is 0.02mol / g. To simplify calculations, this embodiment does not consider the competitive adsorption of MOFs on ethane and other substances, but focuses on their adsorption of methane. It also does not consider the competitive adsorption of methane and other substances by the material inside the adsorption tube, but focuses on their stepwise interception of isobutane and ethane.

[0076] Based on the above parameters, calculate the total residual moles in the gas phase.

[0077] In control group 2, considering that without staged pre-adsorption, heavy components such as isobutane and ethane in the mixed working fluid would clog the micropores of MOFs, leading to a reduction in effective methane adsorption sites, it is assumed that the effective adsorption capacity of MOFs for methane in control group 2 is 0.01 mol / g. The total amount of methane in the mixed working fluid is 10.92 mol (28 mol × 0.39), and the total adsorption capacity of the MOF material is 4 mol (400 g × 0.01 mol / g). Therefore, the remaining methane in the gas phase is 6.92 mol. The total residual moles of methane in the gas phase in the gas storage tank of control group 2 are approximately 24 mol.

[0078] In the experimental group, the total amount of isobutane in the mixed working medium was 11.48 mol (28 mol × 0.41), and the total adsorption capacity of the macroporous material at the top of the adsorption tube was 0.6 mol (100 g × 0.006 mol / g), therefore the remaining isobutane in the gas phase was 10.88 mol. The total amount of ethane in the mixed working medium was 5.6 mol (28 mol × 0.2), and the total adsorption capacity of the mesoporous material at the bottom was 0.5 mol (100 g × 0.005 mol / g), therefore the remaining ethane in the gas phase was 5.1 mol. The total amount of methane in the mixed working medium was 10.92 mol (28 mol × 0.39), and the total adsorption capacity of the MOFs material was 4 mol (200 g × 0.02 mol / g), therefore the remaining methane in the gas phase was 6.92 mol. Based on comprehensive calculations, the total residual moles of the gas phase in the gas storage tank of the experimental group are approximately 22.9 mol (10.88 mol isobutane + 6.92 mol methane + 5.1 mol ethane).

[0079] The static pressure was calculated using NIST's REFPROP 10.0 software. The molar density of control group 1 was 28 / 40 = 0.7 mol / L, with a static pressure of 12.9 bar; the molar density of control group 2 was 24 / 40 = 0.6 mol / L, with a static pressure of approximately 10.7 bar; the molar density of the experimental group (this invention) was 22.9 / 40 = 0.5725 mol / L, with a static pressure of 10.4 bar. Compared to control group 1, the pressure reduction in the experimental group was 20%; compared to control group 2, the pressure reduction was 3%, indicating that the hierarchical adsorption structure of this invention is superior to that of a single adsorbent material. The results are as follows. Figure 12 As shown above, the results demonstrate that by precisely matching the pore size distribution of the adsorbent material with the molecular size of each component in the mixed working fluid, a stepwise and efficient interception of isobutane, ethane, and methane is achieved. This significantly reduces the load during compressor restart, avoids current surges caused by high-pressure startup, and effectively improves the safety and reliability of the system.

[0080] The embodiments of this application have been described above with reference to the accompanying drawings. Unless otherwise specified, the embodiments and features in the embodiments of this application can be combined with each other. This application is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of this application without departing from the spirit and scope of the claims, and all of these forms are within the protection scope of this application.

Claims

1. A dual-adsorption refrigerant pressure-reducing gas storage tank, characterized in that, include: The main tank (6) is a pressure vessel structure with an internal gas storage chamber; A top flange cover (5) is provided on the top of the main tank body (6) and is sealed to the main tank body (6). A filter assembly (14) is disposed above the top flange cover (5) and communicates with the interior of the main tank (6) for filtering the refrigerant gas entering the main tank (6); An adsorption component (15) is disposed inside the main tank (6) and communicates with the filter component (14) for gradient adsorption of different components in the mixed working fluid (30); The adsorption assembly (15) includes an adsorption tube (11) extending axially along the main tank (6) and a stainless steel mesh grid (7) surrounding the outside of the adsorption tube (11). The adsorption tube (11) is provided with a porous partition (13), which divides the internal space of the adsorption tube (11) into a first adsorption layer (34) and a second adsorption layer (35) arranged sequentially along the airflow direction. A third adsorption layer (36) is formed between the stainless steel mesh grid (7) and the inner wall of the main tank (6). The adsorption pore sizes of the first adsorption layer (34), the second adsorption layer (35) and the third adsorption layer (36) decrease sequentially along the airflow direction, and the third adsorption layer (36) is filled with a metal-organic framework material.

2. The dual-adsorption refrigerant pressure-reducing gas storage tank according to claim 1, characterized in that, The filter assembly (14) includes a filter housing (2), a filter element (10), and a fixing spring (9) that presses the filter element (10). The filter housing (2) is wrapped around the outside of the filter element (10) and the fixing spring (9). It has an adapter (1) at its upper and lower ends. The upper adapter (1) is connected to the air inlet pipe of the refrigeration system, and the lower adapter (1) is connected to the adsorption assembly (15).

3. The dual-adsorption refrigerant pressure-reducing gas storage tank according to claim 1, characterized in that, The inner bottom surface of the main tank (6) and the top flange cover (5) are respectively provided with connecting parts (8), and the upper and lower ends of the stainless steel mesh grid (7) are respectively fixed to the corresponding connecting parts (8).

4. The dual-adsorption refrigerant pressure-reducing gas storage tank according to claim 3, characterized in that, The connecting part (8) includes a slot. The upper and lower ends of the stainless steel mesh grid (7) are respectively inserted into the corresponding slots and can be detachably fixed by the second connecting screw (12). A metal contact interface is formed between the outer wall of the end of the stainless steel mesh grid (7) and the inner wall of the slot of the connecting part (8).

5. The dual-adsorption refrigerant pressure-reducing gas storage tank according to claim 2, characterized in that, The top flange cover (5) is provided with multiple external interfaces (3), including a central external interface and an inner ring external interface. The central external interface is located at the center of the top flange cover (5). The adapter (1) at the lower end of the filter assembly (14) is connected to the adsorption assembly (15) at the central external interface. The inner ring external interface includes at least an exhaust interface, a safety interface, and a pressure and temperature measurement interface, which are used for gas discharge, overpressure protection, and status monitoring, respectively.

6. The dual-adsorption refrigerant pressure-reducing gas storage tank according to claim 1, characterized in that, The main tank (6) is a vertical cylindrical structure, and the top flange cover (5) is sealed and fixedly connected to the main tank (6) by a plurality of first connecting screws (4).

7. The dual-adsorption refrigerant pressure-reducing gas storage tank according to claim 6, characterized in that, Multiple first connecting screws (4) are evenly distributed along the circumference of the top flange cover (5). The top flange cover (5) is provided with an outer ring interface corresponding to each of the multiple first connecting screws (4). The outer ring interface and the inner ring interface for installing the exhaust interface, safety interface and pressure and temperature measurement interface are arranged in concentric circles on the top flange cover (5).

8. The dual-adsorption refrigerant pressure-reducing gas storage tank according to claim 1, characterized in that, The outer wall of the main tank (6) is provided with a rib structure.

9. The dual-adsorption refrigerant pressure-reducing gas storage tank according to claim 1, characterized in that, The bottom outer side of the main tank (6) is wrapped with a compressor exhaust pipe (50), which is provided with a first air inlet (51) and a first air outlet (52) for heating the tank by using the heat from the compressor exhaust.

10. The dual-adsorption refrigerant pressure-reducing gas storage tank according to claim 1, characterized in that, The first adsorption layer (34) is filled with one or more of SBA-15 mesoporous molecular sieve, NU-1000 or MIL-101 metal-organic framework materials, the second adsorption layer (35) is filled with one or more of activated carbon, 13X molecular sieve, Mn-PNMI or ZIF-7 metal-organic framework materials, and the third adsorption layer (36) is filled with one or more of MOF-5, CD-MOF-S1, ZIF-8, MOF-700, MIL-53, MOF-702, MOF-703, MOF-701, PCN-14, HKUST-1, Mg-MOF-74, Co-MOF-74 or Ni-MOF-74 materials.

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