A multi-stage membrane separation carbon dioxide capture device

Abstract

The utility model belongs to environmental engineering technical field especially is a kind of multistage membrane separation carbon dioxide capture device, including base, the surface of base is sequentially provided with pretreatment tank, first membrane separation unit, second membrane separation unit, third membrane separation unit and storage tank, the pretreatment tank the first membrane separation unit the second membrane separation unit the third membrane separation unit and the storage tank are communicated by connecting assembly between two, the surface of pretreatment tank is fixedly connected with raw material gas input interface, the connecting assembly is by first connecting pipe, second connecting pipe, connecting flange, fastening bolt, fastening nut and sealing washer is formed;The utility model integrates pretreatment and multistage membrane separation unit in unified base by modularization design, realizes the compact layout and quick installation of equipment, three-stage membrane separation and circulating pipeline design synergistic effect, significantly improves the capture purity and recovery efficiency of carbon dioxide.

Description

Technical Field

[0001] This utility model belongs to the field of environmental engineering technology, specifically relating to a multi-stage membrane separation carbon dioxide capture device. Background Technology

[0002] Carbon dioxide is a key component of Earth's natural carbon cycle and is essential for maintaining ecosystems and surface temperatures. However, since the Industrial Revolution, human activities have led to a sharp increase in atmospheric carbon dioxide concentration, disrupting the natural carbon balance. Excessive carbon dioxide is like a thick blanket covering the Earth, producing a strong "greenhouse effect" and triggering a series of severe ecological and environmental crises such as global warming, frequent extreme weather events, and rising sea levels. Therefore, in order to mitigate climate change, we not only need to reduce carbon emissions, but also actively remove excess carbon dioxide from emission sources or the air. Carbon dioxide capture devices are the core technological tools for achieving this goal. They can efficiently separate and capture carbon dioxide from the flue gas of emission sources such as power plants and factories, or directly from the ambient air. The captured carbon dioxide can be used for resource utilization, such as producing fertilizers, carbonated beverages or synthetic fuels, or it can be safely stored deep underground, thereby directly reducing the net carbon dioxide content in the atmosphere and providing a key technological path for addressing climate change. In this existing design, the functional units of the traditional capture device are usually arranged in a discrete layout and connected by on-site pipeline welding. This mode results in a large footprint and loose structure of the entire device. Not only is the on-site installation cycle long and highly dependent on professional workers, but subsequent maintenance or replacement of core components often requires major changes, resulting in high maintenance costs and long system downtime. Secondly, single-stage or simple membrane separation processes have inherent limitations and often face the dilemma of sacrificing recovery rate to maintain purity, or reducing purity to maintain recovery rate. The residual gas that does not meet the standards is usually directly discharged, which not only wastes carbon resources but also reduces the economics of the entire capture project. Therefore, a multi-stage membrane separation carbon dioxide capture device was designed to solve the above problems. Utility Model Content

[0003] To address the problems mentioned in the background section, this invention provides a multi-stage membrane separation carbon dioxide capture device. This device integrates pretreatment and multi-stage membrane separation units onto a unified base through a modular design, achieving a compact layout and rapid installation. The synergistic effect of the three-stage membrane separation and circulation pipeline design significantly improves the purity and recovery efficiency of carbon dioxide capture.

[0004] To achieve the above objectives, this utility model provides the following technical solution: A multi-stage membrane separation carbon dioxide capture device includes a base, on the surface of which a pretreatment tank, a first membrane separation unit, a second membrane separation unit, a third membrane separation unit, and a storage tank are sequentially arranged. The pretreatment tank, the first membrane separation unit, the second membrane separation unit, the third membrane separation unit, and the storage tank are connected to each other by connecting components. A raw material gas input interface is fixedly connected to the surface of the pretreatment tank. The pretreatment tank, the first membrane separation unit, the second membrane separation unit, the third membrane separation unit, and the storage tank are all symmetrically fixedly connected to mounting bases. The surface of each mounting base is provided with mounting holes. The surface of the base is provided with positioning posts that cooperate with the mounting holes. The bottom end of each positioning post is fixedly connected to a positioning seat. The surface of the base is provided with positioning grooves that cooperate with the positioning seats. The positioning base has symmetrical sliding blocks on its surface, and the interior of the positioning base has guide grooves that cooperate with the blocks. The inner surface of the positioning base is symmetrically fixed with clamping springs. Both sets of blocks have clearance grooves on opposite sides, and the inner surface of the base has slots that cooperate with the blocks.

[0005] In a preferred embodiment of the multi-stage membrane separation carbon dioxide capture device of this utility model, the connecting assembly consists of a first connecting pipe, a second connecting pipe, a connecting flange, fastening bolts, fastening nuts, and a sealing gasket. The connecting flange is fixedly connected to one end of each of the first and second connecting pipes. Four sets of fastening bolts are evenly distributed on the surface of the connecting flange, and the fastening bolts are slidably connected to the connecting flange. The fastening nut is threaded to the tail end of each fastening bolt.

[0006] In a preferred embodiment of the multi-stage membrane separation carbon dioxide capture device of this utility model, the sealing gaskets are fixedly connected to the opposite sides of the connecting flanges.

[0007] In a preferred embodiment of the multi-stage membrane separation carbon dioxide capture device of this utility model, the top end of the third membrane separation unit is fixedly connected to a first return gas pipe, the other end of the first return gas pipe is fixedly connected to the pretreatment tank, the top end of the second membrane separation unit is fixedly connected to a second return gas pipe, and the other end of the second return gas pipe is fixedly connected to the first return gas pipe.

[0008] In a preferred embodiment of the multi-stage membrane separation carbon dioxide capture device of this utility model, the bottom ends of the pretreatment tank, the first membrane separation unit, the second membrane separation unit, the third membrane separation unit, and the storage tank are all fixedly connected to a support base, and the bottom end of the support base is uniformly fixedly connected to four sets of moving wheels.

[0009] In a preferred embodiment of the multi-stage membrane separation carbon dioxide capture device of this utility model, a locking block is fixedly connected to the end of the pretreatment tank away from the first connecting pipe, a locking pin is slidably connected to the surface of the locking block, and a locking threaded hole that cooperates with the locking pin is opened on the surface of the base.

[0010] As a preferred embodiment of the multi-stage membrane separation carbon dioxide capture device of this utility model, a triangular block is fixedly connected to one side of the two sets of card blocks facing away from each other.

[0011] Compared with existing technologies, the advantages of this utility model are as follows: through an innovative modular structure and a precise positioning and locking system, the pretreatment, multi-stage membrane separation and storage units are integrated into one unit. The moving wheels at the bottom of each module make it easy and convenient to move and position, which greatly simplifies the installation and subsequent maintenance of large-scale devices. The design of combining three-stage membrane separation and circulating return gas pipelines purifies carbon dioxide gas step by step and recovers and reprocesses gases that do not meet the standards, thereby significantly improving the overall gas recovery rate while ensuring high purity. Attached Figure Description

[0012] The accompanying drawings are provided to further illustrate the present invention and form part of the specification. They are used together with the embodiments of the present invention to explain the present invention, but do not constitute a limitation thereof. In the drawings: Figure 1 This is a schematic diagram of the overall design of this utility model; Figure 2 This is a schematic diagram of the mounting base in this utility model; Figure 3 In this utility model Figure 2 Enlarged structural diagram at point A; Figure 4 This is a schematic diagram of the locking block in this utility model; Figure 5 This is a schematic diagram of the card block structure in this utility model; In the picture: 1. Base; 2. Pretreatment tank; 201. Raw material gas input interface; 3. First membrane separation unit; 4. Second membrane separation unit; 5. Third membrane separation unit; 6. Storage tank; 7. Connecting assembly; 71. First connecting pipe; 72. Second connecting pipe; 73. Connecting flange; 74. Fastening bolt; 75. Fastening nut; 76. Sealing gasket; 8. First return gas pipe; 9. Second return gas pipe; 10. Mounting base; 11. Mounting hole; 12. Positioning pin; 13. Positioning seat; 14. Positioning groove; 15. Support base; 16. Moving wheel; 17. Locking block; 18. Locking pin; 19. Locking threaded hole; 20. Clamping block; 21. Guide groove; 22. Clamping spring; 23. Clearance groove; 24. Clamping slot; 25. Triangular block. Detailed Implementation

[0013] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model. Example 1

[0014] like Figure 1 As shown; A multi-stage membrane separation carbon dioxide capture device includes a base 1.

[0015] In this implementation plan: In the existing design, the functional units of the traditional capture device are usually connected by discrete layout and on-site pipeline welding. This mode results in a large footprint and loose structure of the entire device. Not only is the on-site installation cycle long and highly dependent on professional workers, but subsequent maintenance or replacement of core components often requires major changes, resulting in high maintenance costs and long system downtime. Secondly, single-stage or simple membrane separation processes have inherent limitations, often facing the dilemma of sacrificing recovery rate to maintain purity, or reducing purity to maintain recovery rate. Substandard permeate gas is usually directly discharged, which not only wastes carbon resources but also reduces the economics of the entire capture project. In combination, this problem is obviously a real and difficult problem to solve.

[0016] Furthermore: This application incorporates the aforementioned prior art, such as Figures 1 to 5 As shown: Based on the above: A multi-stage membrane separation carbon dioxide capture device, wherein a pretreatment tank 2, a first membrane separation unit 3, a second membrane separation unit 4, a third membrane separation unit 5, and a storage tank 6 are sequentially arranged on the surface of a base 1. The pretreatment tank 2, the first membrane separation unit 3, the second membrane separation unit 4, the third membrane separation unit 5, and the storage tank 6 are connected in pairs through a connecting assembly 7. A raw material gas input interface 201 is fixedly connected to the surface of the pretreatment tank 2. The connecting assembly 7 consists of a first connecting pipe 71, a second connecting pipe 72, a connecting flange 73, fastening bolts 74, fastening nuts 75, and a sealing gasket 76. A connecting flange 73 is fixedly connected to one end of the first connecting pipe 71 and the second connecting pipe 72. Four sets of fastening bolts 74 are evenly distributed on the surface of the connecting flange 73, and the fastening bolts 74 are slidably connected to the connecting flange 73. A fastening nut 75 is threaded to the tail end of the fastening bolt 74. A sealing gasket 76 is fixedly connected to one side of the connecting flange 73.

[0017] In this implementation scheme: the raw gas enters the pretreatment tank 2 through the raw gas input interface 201. After pretreatment such as dust removal, cooling, and desulfurization, it flows sequentially through the connecting assembly 7 into the first membrane separation unit 3, the second membrane separation unit 4, and the third membrane separation unit 5 for graded separation and purification. Finally, high-purity CO2 is sent to the storage tank 6 through the connecting assembly 7. The first connecting pipe 71 and the second connecting pipe 72 are connected by the connecting flange 73. After four sets of fastening bolts 74 are inserted into the connecting flange 73, they are tightened by the fastening nut 75 to achieve a sealed connection. The sealing gasket 76 further enhances the airtightness of the connection and ensures stable gas transmission between units. At the same time, the structural design of the first connecting pipe 71 and the second connecting pipe 72 realizes the flow channel layout of lower side outlet and upper side inlet, ensuring orderly gas transmission between units. The modular series unit layout makes the pretreatment, separation, and storage functions clearly divided, which is convenient for later maintenance and upgrades.

[0018] Furthermore: In an optional embodiment, the top end of the third membrane separation unit 5 is fixedly connected to a first return gas pipe 8, and the other end of the first return gas pipe 8 is fixedly connected to the pretreatment tank 2. The top end of the second membrane separation unit 4 is fixedly connected to a second return gas pipe 9, and the other end of the second return gas pipe 9 is fixedly connected to the first return gas pipe 8.

[0019] In this embodiment: the gas that does not meet the purity requirements after separation by the second membrane separation unit 4 is transported to the first return gas pipe 8 through the second return gas pipe 9 fixed at its top. The gas that does not meet the purity requirements after separation by the third membrane separation unit 5 is directly transported through the first return gas pipe 8 fixed at its top. Finally, the two types of gas return to the pretreatment tank 2 through the first return gas pipe 8 and re-participate in the pretreatment and subsequent separation process to form a gas cycle. The cycle pipeline design can recover and reuse the gas that is not completely separated, reduce the loss of effective gas, and improve the overall CO2 recovery rate.

[0020] Furthermore: In an optional embodiment, mounting bases 10 are symmetrically fixedly connected to the surfaces of the pretreatment tank 2, the first membrane separation unit 3, the second membrane separation unit 4, the third membrane separation unit 5, and the storage tank 6. Mounting holes 11 are opened on the surface of each mounting base 10, and positioning posts 12 that cooperate with the mounting holes 11 are provided on the surface of the base 1.

[0021] In this embodiment: when installing the pretreatment tank 2, the first membrane separation unit 3, the second membrane separation unit 4, the third membrane separation unit 5, and the storage tank 6, the mounting holes 11 on the mounting base 10, which are symmetrically fixed on the surface of each unit, are aligned with the positioning posts 12 on the surface of the base 1 and inserted. Through the cooperation between the mounting holes 11 and the positioning posts 12, the horizontal displacement of each unit on the base 1 is restricted, and the initial positioning is completed. The cooperation between the positioning posts 12 and the mounting holes 11 ensures that the installation position of each unit on the base 1 is accurate, avoids misalignment of the connecting components 7 due to installation deviation, ensures smooth gas transmission channels, and at the same time provides a foundation for subsequent fixing steps, improving the overall assembly efficiency of the device.

[0022] Furthermore: In an optional embodiment, a positioning seat 13 is fixedly connected to the bottom end of the positioning column 12, and a positioning groove 14 that cooperates with the positioning seat 13 is opened on the surface of the base 1. The bottom ends of the pretreatment tank 2, the first membrane separation unit 3, the second membrane separation unit 4, the third membrane separation unit 5 and the storage tank 6 are all fixedly connected to a support seat 15, and four sets of moving wheels 16 are evenly fixedly connected to the bottom end of the support seat 15.

[0023] In this embodiment: When installing modules such as the pretreatment tank 2 and the first membrane separation unit 3, the operator pushes the module, causing the moving wheels 16 of the support base 15 at the bottom of the module to roll, moving the module on the surface of the base 1. During the movement, the mounting holes 11 of the mounting base 10 on the module surface move synchronously with the module, gradually approaching the base 1. When it is necessary to install the module with the base 1, the positioning pin 12 on the surface of the base 1 is first passed through the mounting holes 11 of the mounting base 10, so that the positioning pin 12 and the mounting holes 11 are initially engaged. Then, the positioning seat 13 at the bottom of the positioning pin 12 is embedded into the positioning groove 14 opened on the surface of the base 1. The module is then pushed further, and the positioning seat... The positioning seat 13 slides along the positioning groove 14 on the surface of the base 1. The positioning groove 14 restricts the trajectory of the positioning seat 13, preventing the positioning seat 13 from deviating from the preset path. In turn, through the linkage between the positioning seat 13 and the positioning column 12, the overall movement trajectory of the module is ensured to be stable, ensuring the accuracy of the docking of the connecting components 7 between the module and other units. The moving wheel 16 converts the sliding friction between the module and the base 1 into rolling friction, reducing the difficulty of moving the module. The positioning seat 13 and the positioning groove 14 form an automatic guide. No additional positioning tools are needed. The module can be accurately aligned by sliding cooperation alone, reducing the dependence on the professionalism of the operator and greatly shortening the installation time.

[0024] Furthermore: In an optional embodiment, a locking block 17 is fixedly connected to the end of the pretreatment tank 2 away from the first connecting pipe 71, a locking pin 18 is slidably connected to the surface of the locking block 17, and a locking threaded hole 19 that mates with the locking pin 18 is opened on the surface of the base 1.

[0025] In this embodiment: when the pretreatment tank 2 moves to the designated position of the base 1 via the moving wheel 16, the locking pin 18, which is slidably connected to the surface of the locking block 17, is pushed so that the locking pin 18 is inserted into the locking threaded hole 19 on the surface of the base 1. Through the cooperation between the locking pin 18 and the locking threaded hole 19, the movement of the pretreatment tank 2 on the base 1 is restricted, preventing the pretreatment tank 2 from shifting due to vibration during device operation, ensuring the docking stability of the connecting component 7. At the same time, the cooperation between the locking pin 18 and the locking threaded hole 19 is convenient for disassembly and assembly, facilitating the later maintenance or replacement of the pretreatment tank 2.

[0026] Furthermore: In an optional embodiment, the positioning base 13 is symmetrically slidably connected with a locking block 20, the positioning base 13 has a guide groove 21 that cooperates with the locking block 20 inside, the inner surface of the positioning base 13 is symmetrically fixedly connected with a locking spring 22, the two sets of locking blocks 20 are provided with a clearance groove 23 on opposite sides, and the inner surface of the base 1 is provided with a locking groove 24 that cooperates with the locking block 20.

[0027] In this embodiment: when installing modules such as the pretreatment tank 2 and the first membrane separation unit 3, the symmetrically slidably connected locking blocks 20 on the surface of the positioning seat 13 move synchronously with the positioning seat 13. The locking spring 22 inside the positioning seat 13 always applies an outward elastic force to the locking blocks 20. When the positioning seat 13 slides to the preset installation position, the locking blocks 20 align with the locking groove 24 on the inner surface of the base 1. The locking spring 22 pushes the locking blocks 20 to slide along the guide groove 21, so that the locking blocks 20 are embedded in the locking groove 24, thus completing the fixation of the positioning seat 13 and the base 1. If disassembly is required, an opposite force is applied to the module, causing the locking blocks 20 to slide inward, compressing the locking spring 22. The locking blocks 20 exit the locking groove 24 along the guide groove 21. The clearance groove 23 on the opposite side of the locking blocks 20 provides space for the compression of the locking spring 22.

[0028] Furthermore: In an optional embodiment, a triangular block 25 is fixedly connected to the opposite side of the two sets of card blocks 20.

[0029] In this embodiment, the inclined structure of the triangular block 25 allows the positioning seat 13 to slide into the positioning groove 14 without the need for manual squeezing of the locking block 20. The locking block 20 can automatically retract by squeezing the edge of the positioning groove 14. Furthermore, the triangular block 25 can serve as a force point during disassembly, making the disassembly operation more convenient.

[0030] Working principle: When the push module is operated, its bottom support 15 drives four sets of moving wheels 16 to roll, causing the module to move. During the movement, the mounting base 10 on the module surface moves synchronously with the module. When the module approaches the preset position of the base 1, the positioning post 12 on the surface of the base 1 is aligned with the mounting hole 11 of the mounting base 10 and inserted. After the positioning post 12 is inserted into the mounting hole 11, the positioning seat 13 at its bottom end is embedded in the positioning groove 14 on the surface of the base 1. As the module continues to be pushed, the positioning seat 13 slides along the positioning groove 14. The positioning groove 14 restricts the trajectory of the positioning seat 13, ensuring the stability of the module's movement trajectory. During the movement, the locking block 20 on the surface of the positioning seat 13 moves synchronously with the positioning seat 13. When the triangular block 25 on the opposite side of the locking block 20 contacts the edge of the positioning groove 14... The edge of the positioning groove 14 presses against the triangular block 25, causing the locking block 20 to slide along the guide groove 21 into the positioning seat 13. Simultaneously, it compresses the clamping spring 22 on the inner surface of the positioning seat 13. When the module moves to the preset installation position, the locking block 20 aligns with the slot 24 on the inner surface of the base 1. The triangular block 25 disengages from the edge of the positioning groove 14, the clamping spring 22 recovers its deformation, and pushes the locking block 20 along the guide groove 21 into the slot 24, completing the fixation of the positioning seat 13 to the base 1. Using this method, the pretreatment tank 2, the first membrane separation unit 3, the second membrane separation unit 4, the third membrane separation unit 5, and the storage tank 6 are installed sequentially. Finally, the locking pin 18 on the surface of the locking block 17 on the pretreatment tank 2 is pushed, causing the locking pin 18 to insert into the locking threaded hole 19 of the base 1, fixing the pretreatment... Position the pretreatment tank 2, then attach the connecting flanges 73 at opposite ends of the first connecting pipe 71 and the second connecting pipe 72 between each pair of pretreatment tank 2, first membrane separation unit 3, second membrane separation unit 4, third membrane separation unit 5, and storage tank 6. The sealing gasket 76 on the opposite side of the connecting flange 73 should be in close contact with the flange. Then, insert four sets of fastening bolts 74 into the holes of the connecting flange 73 for sliding positioning. Next, screw the fastening nuts 75 into the ends of the fastening bolts 74 and tighten them. Through the threaded transmission of the fastening bolts 74 and the fastening nuts 75, the connecting flange 73 is compressed, causing the sealing gasket 76 to deform and fill the flange gap, achieving a sealed connection and completing the pipeline assembly. The raw material gas first enters the pretreatment tank 2 through the raw material gas input interface 201 on the surface of the pretreatment tank 2. After pretreatment operations such as dust removal, cooling, and desulfurization are completed inside the tank to remove impurities from the raw gas, the pretreated gas flows into the first membrane separation unit 3 through the connecting component 7. After primary separation, CO2-deficient gas is discharged from the permeate side, while CO2-rich gas from the permeate side flows into the second membrane separation unit 4 through the connecting component 7. After secondary separation in the second membrane separation unit 4, the permeate gas flows into the third membrane separation unit 5 through the connecting component 7. Gas from the permeate side that does not meet the purity requirements is transported to the first return gas pipe 8 through the second return gas pipe 9. After tertiary separation in the third membrane separation unit 5, high-purity CO2 gas is output from the permeate side, while gas from the permeate side that does not meet the purity requirements is directly transmitted through the first return gas pipe 8. Both types of circulating gas return to the pretreatment tank 2 through the first return gas pipe 8.The high-purity CO2 gas output from the third membrane separation unit 5, re-entering the pretreatment and separation process, is transported to storage tank 6 via connecting component 7. It is temporarily stored in storage tank 6 for later compression, liquefaction, or direct utilization as needed.

[0031] Finally, it should be noted that the above description is merely a preferred embodiment of this utility model and is not intended to limit the utility model. Although the utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. A multi-stage membrane separation carbon dioxide capture device comprising a base (1), characterised in that: The surface of the base (1) is sequentially provided with a pretreatment tank (2), a first membrane separation unit (3), a second membrane separation unit (4), a third membrane separation unit (5), and a storage tank (6). The pretreatment tank (2), the first membrane separation unit (3), the second membrane separation unit (4), the third membrane separation unit (5), and the storage tank (6) are connected to each other through a connecting component (7). The surface of the pretreatment tank (2) is fixedly connected with a raw material gas input interface (201). The surfaces of the pretreatment tank (2), the first membrane separation unit (3), the second membrane separation unit (4), the third membrane separation unit (5), and the storage tank (6) are all symmetrically fixedly connected with mounting bases (10). The surfaces of the mounting bases (10) are all provided with mounting holes (11). The surfaces of the base (1) are provided with positioning posts (12) that cooperate with the mounting holes (11). The bottom end of the positioning posts (12) is fixedly connected with a positioning seat (13). The surfaces of the base (1) are provided with positioning grooves (14) that cooperate with the positioning seats (13). The positioning seat (13) has a symmetrical sliding connection of a locking block (20) on its surface. The positioning seat (13) has a guide groove (21) that cooperates with the locking block (20) inside. The positioning seat (13) has a locking spring (22) that is symmetrically fixedly connected to its inner surface. Both sets of locking blocks (20) have a clearance groove (23) on their opposite sides. The base (1) has a locking groove (24) that cooperates with the locking block (20) on its inner surface.

2. A multi-stage membrane separation carbon dioxide capture device according to claim 1, wherein: The connecting assembly (7) consists of a first connecting pipe (71), a second connecting pipe (72), a connecting flange (73), fastening bolts (74), fastening nuts (75), and a sealing gasket (76). The connecting flange (73) is fixedly connected to one end of the first connecting pipe (71) and the second connecting pipe (72). Four sets of fastening bolts (74) are evenly distributed on the surface of the connecting flange (73), and the fastening bolts (74) are slidably connected to the connecting flange (73). The fastening nut (75) is threaded to the tail end of the fastening bolt (74).

3. A multi-stage membrane separation carbon dioxide capture device according to claim 2, wherein: The sealing gaskets (76) are fixedly connected to the opposite side of the connecting flange (73).

4. The multi-stage membrane separation carbon dioxide capture device of claim 1, wherein: The top end of the third membrane separation unit (5) is fixedly connected to a first return gas pipe (8), and the other end of the first return gas pipe (8) is fixedly connected to the pretreatment tank (2). The top end of the second membrane separation unit (4) is fixedly connected to a second return gas pipe (9), and the other end of the second return gas pipe (9) is fixedly connected to the first return gas pipe (8).

5. The multi-stage membrane separation carbon dioxide capture device of claim 1, wherein: The bottom ends of the pretreatment tank (2), the first membrane separation unit (3), the second membrane separation unit (4), the third membrane separation unit (5) and the storage tank (6) are all fixedly connected to a support base (15), and the bottom end of the support base (15) is evenly fixedly connected to four sets of moving wheels (16).

6. The multi-stage membrane separation carbon dioxide capture device of claim 2, wherein: The pretreatment tank (2) is fixedly connected to a locking block (17) at one end away from the first connecting pipe (71). A locking pin (18) is slidably connected to the surface of the locking block (17). A locking threaded hole (19) that cooperates with the locking pin (18) is opened on the surface of the base (1).

7. The multi-stage membrane separation carbon dioxide capture device of claim 1, wherein: Triangular blocks (25) are fixedly connected to the opposite sides of the two sets of card blocks (20).

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