CO2 separation element and CO2 separation system

Abstract

The objective is to provide a smaller CO2 separation element. [Solution] A CO2 separation layer 22 is placed between an internal ventilation layer 23 that forms a first air passage and an external ventilation layer 24 that forms a second air passage. The internal ventilation layer 23 and the external ventilation layer 24 are provided with flow straightening walls 25 on their sides. By stacking the CO2 separation layer 22, the internal ventilation layer 23, and the external ventilation layer 24 vertically, the CO2 separation element 20 is formed. This configuration allows the CO2 separation layer 22 to be supported by the internal ventilation layer 23 and the external ventilation layer 24, preventing the CO2 separation layer 22 from sagging and blocking the air passage, and as a result, the CO2 separation element 20 can be miniaturized.

Description

Technical Field

[0001] The present invention relates to a CO2 separation element and a CO2 separation system.

Background Art

[0002] In recent years, the development of technologies for selectively separating carbon dioxide (CO2) from mixed gases or the atmosphere has been progressing. These are used for recovering CO2 from exhaust gases or reducing the concentration of CO2 contained in the air of a closed target space, etc.

[0003] For example, a CO2 separation system for reducing the concentration of CO2 contained in the air of a closed target space is known (Patent Document 1). The CO2 separation system has a module (CO2 separation element) that preferentially separates CO2. When air from the target space is supplied to the CO2 separation system, the CO2 contained in the air is preferentially separated and released in the module, so that air with reduced CO2 remains. The CO2 separation system can reduce the concentration of CO2 in the target space by returning this remaining air to the target space.

[0004] Also, conventionally, a hollow fiber type CO2 separation element has been known (for example, Patent Document 2).

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0006] In conventional hollow fiber type CO2 separation elements, the amount of air that can flow through the CO2 separation element is relatively small due to reasons such as high pressure loss in the airflow path, resulting in a small amount of CO2 separation per unit area of ​​the CO2 separation element.

[0007] On the other hand, stacked CO2 separation elements have lower pressure loss in the airflow path compared to other methods, allowing them to be used with relatively high airflow rates. In other words, stacked CO2 separation elements have a high CO2 separation rate per unit area.

[0008] However, in stacked CO2 separation elements, the CO2 separation layers, which are stacked with a predetermined gap (airflow channel), flex, blocking the airflow channel and increasing pressure loss. High pressure loss makes it difficult for air to flow through the CO2 separation element, making it difficult to reduce the stacking gap. In other words, miniaturizing the CO2 separation element by reducing the stacking gap of the CO2 separation layers becomes difficult.

[0009] The present invention aims to solve the above-mentioned conventional problems and to provide a smaller CO2 separation element by providing a configuration in which the air passage is less likely to be blocked even when the stacking spacing is reduced. [Means for solving the problem]

[0010] To achieve this objective, the CO2 separation element according to the present invention comprises a CO2 separation layer that separates a first air passage and a second air passage, a ventilation layer that forms the first and second air passages, and a flow straightening wall provided on the side surface of the ventilation layer that determines the direction of airflow in the first and second air passages. Furthermore, it is formed by alternately stacking the CO2 separation layer and the ventilation layer. This achieves the intended objective. It is something that can be accomplished. [Effects of the Invention]

[0011] According to the present invention, it is possible to further miniaturize the CO2 separation element. [Brief explanation of the drawing]

[0012] [Figure 1] A schematic diagram showing an example of the installation of a CO2 separation system equipped with a CO2 separation element according to Embodiment 1 of the present invention. [Figure 2] (a) and (b) Cross-sectional diagrams showing a simplified configuration of the CO2 separation element installed in the CO2 separation system. [Figure 3] A perspective view showing a laminated structure used as a CO2 separation element according to Embodiment 1 of the present invention. [Figure 4] Exploded perspective view of a CO2 separation element according to Embodiment 1 of the present invention [Figure 5] Exploded perspective view of a CO2 separation element according to Embodiment 2 of the present invention [Figure 6] Exploded perspective view of a CO2 separation element according to Embodiment 3 of the present invention [Figure 7] Exploded perspective view of a CO2 separation element according to Embodiment 4 of the present invention. [Modes for carrying out the invention]

[0013] The embodiments for carrying out the present invention will be described below with reference to the attached drawings. The embodiments described below are all preferred specific examples of the present invention. Therefore, the numerical values, shapes, materials, and components shown in the following embodiments, as well as the arrangement and connection configurations of the components, are examples only and are not intended to limit the present invention. Accordingly, among the components in the following embodiments, those not described in the independent claim representing the highest-level concept of the present invention will be described as optional components. Furthermore, in each figure, substantially identical components are denoted by the same reference numerals, and redundant explanations are omitted or simplified.

[0014] (Embodiment 1) First, the schematic configuration of the CO₂ separation system 1 including the CO₂ separation element 20 according to Embodiment 1 of the present invention will be described with reference to FIG. 1. FIG. 1 is a schematic diagram showing an installation example of the CO₂ separation system 1. The CO₂ separation system 1 is a system that is installed indoors in a building such as a house and separates a target gas (for example, carbon dioxide (CO₂) etc.) from the air 39a in the target space 2 indoors and discharges it outdoors.

[0015] The CO₂ separation system 1 includes a housing 10, a CO₂ separation element 20, an indoor air duct 16, an outdoor air duct 17, an indoor air fan 31, an indoor air filter 37, an outdoor air fan 41, an outdoor air filter 47, a control unit 5, and a CO₂ detection unit 8.

[0016] The housing 10 is a substantially box-shaped member that forms the outer shell of the CO₂ separation system 1. The indoor air duct 16 and the outdoor air duct 17 are independently formed in a manner that divides the internal space formed inside this housing 10. Further, an indoor air inlet 33, an air supply port 35, an outdoor air inlet 43, and an exhaust port 45 are arranged on the outer periphery of the housing 10.

[0017] The indoor air duct 16 is an air duct formed inside the housing 10. The indoor air duct 16 is an air duct through which the air 39a in the target space 2, which is the object of CO₂ removal indoors, is introduced and circulated, and the air 39b with the CO₂ concentration reduced by the CO₂ separation element 20 from the air 39a is refluxed to the target space 2. In the following description, the air 39a and the air 39b are collectively referred to as "indoor air".

[0018] The indoor air inlet 33 is a suction port that sucks the air 39a in the target space​​​​​​​​​The indoor air intake duct 52 is a duct that guides the air 39a from the target space 2, which is drawn in from the indoor intake port 51, to the indoor air outlet 33. One end of the indoor air intake duct 52 is connected to the indoor intake port 51, and the air 39a from the target space 2 flows into the indoor air intake duct 52 as RA. The other end of the indoor air intake duct 52 is connected to the indoor air outlet 33, and the RA flows into the indoor air passage 16. In other words, the indoor air intake duct 52 introduces the air 39a from the target space 2 indoors into the indoor air passage 16 as indoor air and circulates it.

[0021] The air intake port 35 is an outlet that discharges air 39b, which is indoor air with reduced CO2 concentration by the CO2 separation element 20, from the CO2 separation system 1. In other words, the indoor air passage 16 and the indoor air discharge duct 54 are connected in communication via the air intake port 35.

[0022] The indoor air outlet 53 is an opening provided in the indoor target space 2, and supplies air 39b with reduced CO2 concentration to the target space 2 as SA (Supply Air).

[0023] The internal air discharge duct 54 is a duct that guides the air 39b discharged from the CO2 separation system 1 to the indoor air outlet 53. One end of the internal air discharge duct 54 is connected to the air supply port 35, and the air 39b, whose CO2 concentration has been reduced by the CO2 separation element 20, flows into the internal air discharge duct 54. The other end of the internal air discharge duct 54 is connected to the indoor air outlet 53, and the air 39b inside the internal air discharge duct 54 is supplied to the target space 2 as SA. In other words, the internal air discharge duct 54 recirculates the air 39b back into the target space 2.

[0024] The outside air passage 17 is an air passage through which outdoor air 49a is introduced and circulated, and which releases air 49b with increased CO2 concentration to the outside due to the CO2 separation function of the CO2 separation element 20. In the following explanation, air 49a and air 49b will be collectively referred to as "outside air".

[0025] The outside air inlet 43 is an intake port that draws in outdoor air 49a as outside air into the outside air passage 17 of the CO2 separation system 1. The outside air passage 17 and the outside air intake duct 56 are connected via the outside air inlet 43.

[0026] The outdoor intake port 55 is an opening in the exterior wall of the building, and draws in outdoor air 49a as OA (Outside Air) into the outdoor air intake duct 56.

[0027] The outside air intake duct 56 is a duct that guides the air 49a drawn in from the outdoor intake port 55 to the outside air port 43. One end of the outside air intake duct 56 is connected to the outdoor intake port 55, and the air 49a from outside flows into the outside air intake duct 56 as outside air (OA). The other end of the outside air intake duct 56 is connected to the outside air port 43, and the OA flows into the outside air passage 17. In other words, the outside air intake duct 56 introduces the outdoor air 49a as outside air into the outside air passage 17 and circulates it.

[0028] The exhaust port 45 is a discharge port from the CO2 separation system 1 that releases outside air 49b, whose CO2 concentration has increased due to the CO2 being absorbed from the inside air by the CO2 separation element 20. The outside air passage 17 and the outside air discharge duct 58 are connected in communication via the exhaust port 45.

[0029] The outdoor outlet 57 is an opening in the exterior wall of the building, and it discharges the air 49b with increased CO2 concentration to the outside as EA (Exhaust Air).

[0030] The outdoor air discharge duct 58 is a duct that guides the air 49b discharged from the CO2 separation system 1 to the outdoor outlet 57. One end of the outdoor air discharge duct 58 is connected to the exhaust port 45, and the air 49b, whose CO2 concentration has increased due to the CO2 separation element 20, flows into the outdoor air discharge duct 58. The other end of the outdoor air discharge duct 58 is connected to the outdoor outlet 57, and the air 49b inside the outdoor air discharge duct 58 is discharged outdoors as EA. In other words, the outdoor air discharge duct 58 releases the air 49b outdoors.

[0031] Furthermore, the internal air intake duct 52 and the internal air outlet duct 54 may be grouped together with the internal air passage 16 as an "internal air passage," and the external air intake duct 56 and the external air outlet duct 58 may be grouped together with the external air passage 17 as an "external air passage."

[0032] The CO2 separation element 20 is installed inside the housing 10, spanning both the internal air passage 16 and the external air passage 17. It separates CO2 from the air 39a flowing through the internal air passage 16 and releases the separated CO2 into the air 49a flowing through the external air passage 17. Details of the CO2 separation element 20 will be described later.

[0033] The internal fan 31 is installed in the internal air passage 16, for example, downstream of the CO2 separation element 20, and is a blower that blows internal air in the internal air passage 16 by drawing in internal air from the target space 2 through the internal air port 33 and discharging it back into the target space 2 through the air supply port 35.

[0034] By driving the internal fan 31, the internal air drawn in from the target space 2 through the internal air inlet 33 is blown to the CO2 separation element 20 via the internal air filter 37, and then discharged back into the target space 2 through the air intake 35.

[0035] Furthermore, the internal fan 31 may be installed upstream of the CO2 separation element 20, or it may be installed downstream of the internal filter 37 and upstream of the CO2 separation element 20.

[0036] The internal air filter 37 is a filter that removes dust and dirt from the internal air flowing into the housing 10 and supplies the purified air 39a to the CO2 separation element 20. For example, a HEPA (High Efficiency Particulate Air) filter may be used for the internal air filter 37.

[0037] The outside air fan 41 is attached to the outside air passage 17 and is a fan that blows outside air in the outside air passage 17 by drawing in outside air from outdoors through the outside air port 43 and discharging it outdoors through the exhaust port 45.

[0038] By driving the outside air fan 41, outside air drawn in from outside through the outside air inlet 43 is blown to the CO2 separation element 20 via the outside air filter 47, and then discharged to the outside via the exhaust port 45.

[0039] The outside air fan 41 is installed, for example, upstream of the CO2 separation element 20, preferably downstream of the outside air filter 47 and upstream of the CO2 separation element 20. With this arrangement, the outside air can be heated by the heat generated by the operation of the outside air fan 41, and when the outside air is colder than the inside air, the heat loss due to heat exchange between the outside air and the inside air is reduced. However, the outside air fan 41 may also be installed downstream of the CO2 separation element 20.

[0040] The outside air filter 47 is a filter that removes dust and dirt from the outside air that flows into the housing 10 and supplies the purified air 49a to the CO2 separation element 20. For example, a HEPA filter is used.

[0041] The CO2 detection unit 8 is attached to the indoor air intake duct 52 and detects the CO2 concentration in the air 39a flowing through the indoor air intake duct 52. The air 39a flowing through the indoor air intake duct 52 is air taken in from the target space 2. Therefore, the CO2 concentration detected by the CO2 detection unit 8 corresponds to the CO2 concentration in the target space 2.

[0042] Information regarding the CO2 concentration in the target space 2 detected by the CO2 detection unit 8 is transmitted to the control unit 5. Alternatively, the CO2 detection unit 8 may be directly attached to the target space 2 to detect the CO2 concentration within the target space 2 and transmit the detected CO2 concentration to the control unit 5.

[0043] The control unit 5 controls the internal fan 31 and the external fan 41. Specifically, based on the CO2 concentration in the target space 2 detected by the CO2 detection unit 8, the control unit 5 determines the CO2 separation efficiency of the CO2 separation element 20 to reduce the CO2 concentration of the air in the target space 2 that has that CO2 concentration. The control unit 5 determines the airflow rate of the internal fan 31 (internal airflow rate) and the airflow rate of the external fan 41 (external airflow rate) to achieve the determined CO2 separation efficiency. Then, the control unit 5 controls the internal fan 31 to achieve the determined internal airflow rate and the external fan 41 to achieve the determined external airflow rate.

[0044] Next, an overview of CO2 separation by the CO2 separation element 20 will be explained using Figure 2. First, Figure 2(a) is a simplified cross-sectional view showing the configuration of the CO2 separation element 20. In Figure 2(a), an internal air ventilation layer 23 through which internal air flows from left to right and an external air ventilation layer 24 through which external air flows from left to right are shown stacked vertically. Note that the labels "upper" and "lower" in Figures 2(a) and 2(b) are merely for explanatory purposes and do not intend to limit the orientation of the CO2 separation element 20.

[0045] The internal air introduced into the internal ventilation layer 23 is a mixture of carbon dioxide 18 (CO2) and nitrogen 19 (N2). Actual air also contains oxygen (O2), etc., but for the sake of clarity in this explanation, O2, etc. will be omitted. The air circulating in the external ventilation layer 24 also contains at least arbitrary gas molecules, but for the sake of clarity in this explanation, the diagram will be omitted. If the air circulating in the external ventilation layer 24 is outdoor air, then arbitrary gas molecules include, for example, oxygen, carbon dioxide, nitrogen, etc. The "internal ventilation layer 23" and the "external ventilation layer 24" are collectively referred to as the "ventilation layer."

[0046] The CO2 separation element 20 has a CO2 separation layer 22 positioned between the internal air ventilation layer 23 that forms the first air passage 80 and the external air ventilation layer 24 that forms the second air passage 90.

[0047] The CO2 separation layer 22 has the function of selectively permeating CO2 from the air, and its form is not limited to a gel or thin film, for example.

[0048] The first air passage 80 is located below the CO2 separation layer 22 in Figure 2(a) and is formed by the internal air ventilation layer 23. In this embodiment, internal air flows through the first air passage 80.

[0049] The second air passage 90 is located above the CO2 separation layer 22 in Figure 2(a) and is formed by the outside air ventilation layer 24. In this embodiment, outside air flows through the second air passage 90.

[0050] The internal ventilation layer 23 is composed of a porous material such as a nonwoven fabric or a mesh-like spacer. In other words, the internal ventilation layer 23 supports the CO2 separation layer 22. Thus, the CO2 separation layer 22 is configured to allow air to circulate while suppressing bending. In this embodiment, as an example, the width of the internal air ventilation layer 23 in the vertical direction is, for example, about 1 mm, which is wider than the width of the CO2 separation layer 22. The internal air ventilation layer 23 is an air passage within the CO2 separation element 20, and air 39a from the target space 2 that has passed through the indoor intake port 51, the internal air introduction duct 52, and the internal air outlet 33 is introduced into the internal air ventilation layer 23 (see Figure 1). The air 39b, whose CO2 concentration has been reduced after passing through the internal air ventilation layer 23, passes through the air supply port 35 and the internal air discharge duct 54, and is returned to the target space 2 from the indoor outlet port 53.

[0051] The outside air ventilation layer 24 is made of a porous material such as a nonwoven fabric or a mesh-like spacer. In other words, the outside air ventilation layer 24 supports the CO2 separation layer 22, thereby suppressing the bending of the CO2 separation layer 22 while allowing outside air to ventilate (not shown in Figure 2(a)). In this embodiment, as an example, the width of the outside air ventilation layer 24 in the vertical direction is, for example, about 1 mm, which is wider than the width of the CO2 separation layer 22. The outside air ventilation layer 24 is an air passage within the CO2 separation element 20, and outside air 49a that has passed through the outdoor intake port 55, the outside air introduction duct 56, and the outside air port 43 is introduced into the outside air ventilation layer 24 (see Figure 1). The air 49b, whose CO2 concentration has increased after passing through the outside air ventilation layer 24, passes through the exhaust port 45 and the outside air discharge duct 58, and is exhausted to the outside from the outdoor outlet port 57.

[0052] Furthermore, in order for the CO2 separation element 20 to permeate more CO2 from the indoor air to the outdoor air, the airflow rate of the indoor air needs to be greater than, for example, the airflow rate of the outdoor air. For this reason, it is desirable that the airflow rate of the indoor air flowing through the indoor ventilation layer 23 be about the same as, or greater than, the airflow rate of the outdoor air flowing through the outdoor ventilation layer 24.

[0053] Therefore, it is preferable to design the system so that the pressure loss generated by the porous material constituting the internal ventilation layer 23 is equal to or smaller than the pressure loss generated by the porous material constituting the external ventilation layer 24. In other words, it is desirable to determine the combination of porous materials used in the internal ventilation layer 23 and the external ventilation layer 24 so that the pressure loss relationship described above is met. Specifically, it is preferable that the fiber density of the porous material used in the internal ventilation layer 23 is lower than the fiber density of the porous material used in the external ventilation layer 24. Here, fiber density refers to the ratio of voids per unit volume of the porous material used in the internal ventilation layer 23 or the external ventilation layer 24. In other words, a high void ratio per unit volume is considered to be low fiber density, and a low void ratio per unit volume is considered to be high fiber density.

[0054] As the internal air flows through the internal ventilation layer 23 along the CO2 separation layer 22, the CO2 separation layer 22 selectively separates (permeates) carbon dioxide 18 (CO2) from the internal air and releases the carbon dioxide 18 into the outside air through the external ventilation layer 24. As a result, the concentration of carbon dioxide 18 in the internal air decreases, while the concentration of carbon dioxide 18 in the outside air increases.

[0055] Figure 2(b) is a simplified cross-sectional view showing the configuration of the CO2 separation element 20 for more efficient separation of carbon dioxide 18 than that shown in Figure 2(a). The CO2 separation element 20 shown in Figure 2(b) includes the first to third internal ventilation layers 23a to 23c, collectively referred to as the internal ventilation layer 23; the first to third external ventilation layers 24a to 24c, collectively referred to as the external ventilation layer 24; and the first to fifth CO2 separation layers 22a to 22e, collectively referred to as the CO2 separation layer 22. Note that the number of internal ventilation layers 23 and external ventilation layers 24 is not limited to "3".

[0056] In Figure 2(b), the first outside ventilation layer 24a, the first inside ventilation layer 23a, the second outside ventilation layer 24b, the second inside ventilation layer 23b, the third outside ventilation layer 24c, and the third inside ventilation layer 23c are arranged in order from top to bottom.

[0057] Furthermore, between the first outside air ventilation layer 24a and the first inside air ventilation layer 23a, there is a first CO2 separation layer 22 Layer a is placed. A second CO2 separation layer 22b is placed between the first internal ventilation layer 23a and the second external ventilation layer 24b. A third CO2 separation layer 22c is placed between the second external ventilation layer 24b and the second internal ventilation layer 23b. A fourth CO2 separation layer 22d is placed between the second internal ventilation layer 23b and the third external ventilation layer 24c. A fifth CO2 separation layer 22e is placed between the third external ventilation layer 24c and the third internal ventilation layer 23c.

[0058] Similar to Figure 2(a), carbon dioxide 18 in the internal air circulating within the internal air ventilation layer 23 is selectively separated (permeated) in the CO2 separation layer 22 and released into the outside air in the external air ventilation layer 24.

[0059] Next, the structure of the CO2 separation element 20 will be explained using Figures 3 and 4.

[0060] Figure 3 is a perspective view showing a laminated structure 6 used as a CO2 separation element 20 mounted in the CO2 separation system 1. For the sake of explanation, the stacking direction of the laminated structure 6 will be described as the vertical up-and-down direction below, but this does not necessarily represent the direction when the laminated structure 6 is mounted in the CO2 separation system 1.

[0061] The laminated structure 6 is constructed by stacking a CO2 separation layer 22, an internal ventilation layer 23, and an external ventilation layer 24 in the vertical direction. The internal ventilation layer 23 or the external ventilation layer 24 is positioned on either the upper or lower surface, sandwiching the CO2 separation layer 22. The CO2 separation layer 22 is stacked alternately in layers, one layer at a time, so as to be in contact with the internal ventilation layer 23 and the external ventilation layer 24. In other words, the laminated structure 6 consists of alternating stacks of CO2 separation layers 22 and porous materials (internal ventilation layer 23 or external ventilation layer 24). More specifically, along the stacking direction, the CO2 separation layer 22, internal ventilation layer 23, CO2 separation layer 22, and external ventilation layer 24 are repeatedly stacked in that order.

[0062] The internal air (air 39a) flowing through the internal ventilation layer 23 and the external air (air 49a) flowing through the external ventilation layer 24 flow in directions perpendicular to each other. This allows the CO2 separation element 20 to selectively permeate CO2 from the internal air side to the external air side via the CO2 separation layer 22.

[0063] Furthermore, in order to miniaturize the CO2 separation element 20, it is desirable that the vertical length (height) of the CO2 separation layer 22 be smaller than the height of the internal air ventilation layer 23 and the external air ventilation layer 24.

[0064] Furthermore, if the pressure loss of the porous material constituting the internal ventilation layer 23 and the external ventilation layer 24 increases, more energy will be required to secure the desired airflow rates for the internal and external air. For this reason, in order to reduce the pressure loss of the internal ventilation layer 23 and the external ventilation layer 24, it is desirable to make the height of the laminated structure 6 greater than the length of the laminated structure 6 in the direction of internal air flow and the direction of external air flow.

[0065] Furthermore, the structure of the CO2 separation element 20 will be described in more detail with reference to Figure 4. Figure 4 is an exploded perspective view of the CO2 separation element 20 according to Embodiment 1 of the present invention.

[0066] The internal ventilation layer 23 and the external ventilation layer 24, which are located above and below the CO2 separation layer 22, have a flow-straightening wall portion 25.

[0067] The rectifying wall portion 25 is installed to block the pores of the porous material constituting the internal air ventilation layer 23 and the external air ventilation layer 24, sealing the outer periphery of the internal air ventilation layer 23 and the outer periphery of the external air ventilation layer 24 to prevent internal and external air from passing through. In other words, the rectifying wall portion 25 is provided on the side surface of the laminated structure 6 (CO2 separation element 20). More specifically, the rectifying wall portion 25 is provided on the side surface of the internal air ventilation layer 23 or the external air ventilation layer 24.

[0068] The rectifying walls 25 in the internal ventilation layer 23 are installed on two opposing sides that are parallel to the direction of airflow of the internal air introduced into the internal ventilation layer 23. More specifically, the rectifying walls 25 in the internal ventilation layer 23 are provided on two sides of the internal ventilation layer 23, which is roughly rectangular in shape when viewed in a plan view in the stacking direction, that are approximately parallel to the direction of airflow. In other words, the rectifying walls 25 provided in the internal ventilation layer 23 determine the direction of airflow.

[0069] This configuration prevents the internal air introduced into the internal ventilation layer 23 from flowing out of the internal ventilation layer 23 through unintended paths.

[0070] The flow-straightening walls 25 in the outside air ventilation layer 24 are installed on two sides that are parallel to and opposite the direction of the flow of outside air introduced into the outside air ventilation layer 24. More specifically, the flow-straightening walls 25 in the outside air ventilation layer 24 are provided on two sides of the outside air ventilation layer 24, which is roughly rectangular in shape when viewed in a plan view in the stacking direction, that are approximately parallel to the direction of outside air ventilation. In other words, the flow-straightening walls 25 provided in the outside air ventilation layer 24 determine the direction of outside air flow.

[0071] This configuration prevents outside air introduced into the outside air ventilation layer 24 from flowing out of the outside air ventilation layer 24 through unintended paths.

[0072] In this embodiment, the rectifying wall portion 25 provided in the outside air ventilation layer 24 is provided approximately perpendicular to the rectifying wall portion 25 provided in the inside air ventilation layer 23 when viewed in a plan view in the stacking direction. The rectifying wall portion 25 is constructed, for example, by adhesive or heat sealing.

[0073] In this embodiment, the CO2 separation element 20 is formed by stacking single structures made of an internal ventilation layer 23 (or external ventilation layer 24) and a CO2 separation layer 22. More specifically, the CO2 separation element 20 is formed by alternately stacking single structures 110 made of the internal ventilation layer 23 and the CO2 separation layer 22, and single structures 120 made of the external ventilation layer 24 and the CO2 separation layer 22. In this embodiment, as an example, the CO2 separation layer 22 is formed without any gaps between the CO2 separation layer 22 and the internal ventilation layer 23 or the external ventilation layer 24.

[0074] Furthermore, since the internal ventilation layer 23 or the external ventilation layer 24 is a porous material, it has numerous pores on one surface. However, "without gaps" means that one surface of the CO2 separation layer 22 and one surface of the internal ventilation layer 23 (external ventilation layer 24) are arranged to overlap so as to cover these pores. In other words, "without gaps" means that one surface of the CO2 separation layer 22 and one surface of the internal ventilation layer 23 (external ventilation layer 24) are formed on approximately the same plane. Moreover, "without gaps" has a design meaning and includes cases where voids occur during the manufacturing process, for example.

[0075] The CO2 separation system 1 equipped with the CO2 separation element 20 according to Embodiment 1 of the present invention, as described above, separates CO2 from the air 39a in the target space 2 using the CO2 separation element 20 and releases it outdoors, thereby reducing the CO2 concentration in the target space 2.

[0076] Furthermore, the CO2 separation element 20 according to Embodiment 1 is constructed by stacking a CO2 separation layer 22, an internal ventilation layer 23, and an external ventilation layer 24 in the vertical direction. The CO2 separation layer 22 is a structure in which layers are alternately stacked one by one so as to be in contact with the internal ventilation layer 23 and the external ventilation layer 24, and the internal ventilation layer 23 and the external ventilation layer 24 are provided with a flow straightening wall portion 25.

[0077] With this configuration, the CO2 separation layer 22 is supported by the internal air ventilation layer 23 or the external air ventilation layer 24, so the CO2 separation layer 22 flexes, and the internal air inside the CO2 separation element 20 This prevents the blockage of the outside airflow path.

[0078] As a result, the height of each air passage in the stacking direction can be designed to be lower, making it possible to miniaturize the CO2 separation element 20.

[0079] In other words, even if the airflow path is made thinner, it becomes less likely to collapse, allowing for a more multilayer structure in the CO2 separation element compared to a CO2 separation element of the same height. As a result, the CO2 separation performance can be improved.

[0080] (Embodiment 2) First, Embodiment 2 will be described using Figure 5. In Figure 5, components similar to those in Figures 1 to 4 are denoted by the same reference numerals, and their detailed descriptions may be omitted or simplified.

[0081] Figure 5 is an exploded perspective view of the CO2 separation element 20a according to Embodiment 2 of the present invention. Embodiment 2 differs from Embodiment 1 in the configuration of the CO2 separation element 20a.

[0082] The CO2 separation element 20a according to Embodiment 2 of the present invention has a structure in which a first CO2 separation membrane 60a and a second CO2 separation membrane 60b are alternately stacked in the vertical direction. The first CO2 separation membrane 60a is also referred to as the "first membrane," and the second CO2 separation membrane 60b is also referred to as the "second membrane."

[0083] The first CO2 separation membrane 60a is composed of a CO2 separation layer 22, a first front ventilation layer 61a, and a first back ventilation layer 62a. The first front ventilation layer 61a is positioned above the CO2 separation layer 22, and the first back ventilation layer 62a is positioned below it.

[0084] The first front-side ventilation layer 61a is an air passage within the CO2 separation element 20a, which is made of a porous material, and outdoor air 49a is introduced through it. The first front-side ventilation layer 61a is equipped with a front-side rectifying wall portion 25a.

[0085] The front-side rectifying wall portion 25a in the first front-side ventilation layer 61a is provided on two sides of the first front-side ventilation layer 61a, which has a roughly rectangular shape when viewed in plan in the stacking direction, that are approximately parallel to the direction of outside air ventilation. In other words, the front-side rectifying wall portion 25a provided in the first front-side ventilation layer 61a determines the direction of outside air flow. Furthermore, the first front-side ventilation layer 61a is provided such that the front-side rectifying wall portion 25a provided in the first front-side ventilation layer 61a overlaps with the back-side rectifying wall portion 25b provided in the second back-side ventilation layer 62b. In other words, the first front-side ventilation layer 61a is provided overlapping with the second back-side ventilation layer 62b to form the outside air ventilation layer 24.

[0086] The first rear ventilation layer 62a is an air passage within the CO2 separation element 20a, which is made of a porous material, and air 39a from the target space 2 is introduced through it. The first rear ventilation layer 62a is equipped with a rear rectifying wall portion 25b.

[0087] The back-side rectifying wall portion 25b in the first back-side ventilation layer 62a is provided on two sides of the first back-side ventilation layer 62a, which has a roughly rectangular shape when viewed in plan in the stacking direction, that are approximately parallel to the direction of ventilation of the interior air. In other words, the back-side rectifying wall portion 25b provided in the first back-side ventilation layer 62a determines the direction of airflow. Furthermore, the back-side rectifying wall portion 25b provided in the first back-side ventilation layer 62a is provided so as to overlap with the front-side rectifying wall portion 25a provided in the second front-side ventilation layer 61b (not shown). In other words, the first back-side ventilation layer 62a is provided overlapping with the second front-side ventilation layer 61b to form the interior ventilation layer 23.

[0088] Furthermore, in the first CO2 separation membrane 60a, the two sides on which the front-side rectifying wall 25a is installed and the two sides on which the back-side rectifying wall 25b is installed are arranged to be perpendicular to each other. In other words, the outside air flowing through the first front-side ventilation layer 61a and the inside air flowing through the first back-side ventilation layer 62a and 61b are arranged to be perpendicular to each other.

[0089] The second CO2 separation membrane 60b is composed of a CO2 separation layer 22, a second front-side ventilation layer 61b, and a second back-side ventilation layer 62b. The second front-side ventilation layer 61b is positioned above the CO2 separation layer 22, and the second back-side ventilation layer 62b is positioned below it.

[0090] The second front-side ventilation layer 61b is an air passage within the CO2 separation element 20a, which is made of a porous material, and indoor air 39a is introduced through it. The "first front-side ventilation layer 61a" and the "second front-side ventilation layer 61b" are collectively referred to as the "front-side ventilation layer." The second front-side ventilation layer 61b includes a front-side flow straightening wall portion 25a.

[0091] The front-side rectifying wall portion 25a in the second front-side ventilation layer 61b is provided on two sides of the second front-side ventilation layer 61b, which has a roughly rectangular shape when viewed in plan in the stacking direction, that are approximately parallel to the direction of ventilation of the interior air. In other words, the front-side rectifying wall portion 25a provided in the second front-side ventilation layer 61b determines the direction of airflow for the interior air. Furthermore, the second front-side ventilation layer 61b is provided such that the front-side rectifying wall portion 25a provided in the second front-side ventilation layer 61b overlaps with the back-side rectifying wall portion 25b provided in the first back-side ventilation layer 62a. In other words, the second front-side ventilation layer 61b is provided overlapping with the first back-side ventilation layer 62a to form the interior air ventilation layer 23.

[0092] The second rear ventilation layer 62b is an air passage within the CO2 separation element 20a, composed of a porous material, through which outdoor air 49a is introduced. The first rear ventilation layer 62a and the second rear ventilation layer 62b are collectively referred to as the "rear ventilation layer." The second rear ventilation layer 62b includes a rear flow straightening wall portion 25b.

[0093] The back-side rectifying wall portion 25b in the second back-side ventilation layer 62b is provided on two sides of the second back-side ventilation layer 62b, which has a roughly rectangular shape when viewed in plan in the stacking direction, that are approximately parallel to the direction of outside air ventilation. In other words, the back-side rectifying wall portion 25b provided in the second back-side ventilation layer 62b determines the direction of outside air flow. Furthermore, the second back-side ventilation layer 62b is provided such that the back-side rectifying wall portion 25b provided in the second back-side ventilation layer 62b overlaps with the front-side rectifying wall portion 25a provided in the first front-side ventilation layer 61a. In other words, the second back-side ventilation layer 62b is provided overlapping with the first front-side ventilation layer 61a to form the outside air ventilation layer 24.

[0094] Furthermore, in the second CO2 separation membrane 60b, the two sides on which the front-side rectifying wall 25a is installed and the two sides on which the back-side rectifying wall 25b is installed are arranged to be perpendicular to each other. In other words, the internal air flowing through the second front-side ventilation layer 61b and the external air flowing through the second back-side ventilation layer 62b are arranged to be perpendicular to each other.

[0095] The front-side rectifying wall 25a and the back-side rectifying wall 25b are installed to block the pores of the porous material that constitutes the first front-side ventilation layer 61a, the first back-side ventilation layer 62a, the second front-side ventilation layer 61b, and the second back-side ventilation layer 62b. The front-side rectifying wall 25a and the back-side rectifying wall 25b seal two opposing sides of each layer to suppress unintended inflow and outflow of internal and external air. The front-side rectifying wall 25a and the back-side rectifying wall 25b are constructed, for example, by adhesive or heat sealing.

[0096] Furthermore, the porous material constituting the first front-side ventilation layer 61a, the first back-side ventilation layer 62a, the second front-side ventilation layer 61b, and the second back-side ventilation layer 62b can be, for example, a nonwoven fabric or a mesh-like spacer.

[0097] Furthermore, in order to miniaturize the CO2 separation element 20a, it is desirable that the vertical length (height) of the CO2 separation layer 22 be lower than the heights of the first front ventilation layer 61a, the first back ventilation layer 62a, the second front ventilation layer 61b, and the second back ventilation layer 62b.

[0098] Furthermore, if the pressure loss in the internal and external air passages within the CO2 separation element 20a increases, more energy will be required to ensure the desired flow rates of the internal and external air. For this reason, in order to reduce the pressure loss in the internal and external air passages within the CO2 separation element 20a, it is desirable to make the height of the CO2 separation element 20a greater than the length of the internal and external air passages within the CO2 separation element 20a.

[0099] The CO2 separation element 20a according to Embodiment 2 of the present invention, as described above, has a structure in which a first CO2 separation membrane 60a and a second CO2 separation membrane 60b are alternately stacked in the vertical direction. The first CO2 separation membrane 60a consists of a CO2 separation layer 22, a first front-side ventilation layer 61a, and a first back-side ventilation layer 62a, while the second CO2 separation membrane 60b consists of a CO2 separation layer 22, a second front-side ventilation layer 61b, and a second back-side ventilation layer 62b.

[0100] With this configuration, the CO2 separation layer 22 is supported by two layers: the first back-side ventilation layer 62a and the second front-side ventilation layer 61b, or the first front-side ventilation layer 61a and the second back-side ventilation layer 62b.

[0101] Therefore, compared to the CO2 separation element 20 of Embodiment 1, the CO2 separation layer 22 is supported more reliably, making it possible to achieve the same effects as the CO2 separation element 20 of Embodiment 1 more efficiently.

[0102] (Embodiment 3) Next, Embodiment 3 will be described with reference to Figure 6. In Figure 6, components similar to those in Figures 1 to 5 are denoted by the same reference numerals, and their detailed descriptions may be omitted or simplified.

[0103] Figure 6 is an exploded perspective view of a CO2 separation element 20b according to Embodiment 3 of the present invention. Embodiment 3 differs from Embodiment 2 in that it includes a coarse porous layer between the first front ventilation layer 61a and the second back ventilation layer 62b, or between the second front ventilation layer 61b and the first back ventilation layer 62a. In this embodiment, the coarse porous layer is composed of a first coarse porous layer 63a and a second coarse porous layer 63b.

[0104] The CO2 separation element 20b according to Embodiment 3 of the present invention has a structure in which a first CO2 separation membrane 60a, a first coarse porous layer 63a, a second CO2 separation membrane 60b, and a second coarse porous layer 63b are stacked in the vertical direction.

[0105] The first coarse porous layer 63a is a porous material installed between the first front ventilation layer 61a and the second back ventilation layer 62b. The fiber density of the first coarse porous layer 63a is lower than that of the first front ventilation layer 61a or the second back ventilation layer 62b. In other words, the first coarse porous layer 63a has better air permeability than the first front ventilation layer 61a or the second back ventilation layer 62b, and is less prone to pressure loss. The first coarse porous layer 63a is equipped with a coarse flow straightening wall portion 25c.

[0106] The coarse flow straightening wall portion 25c is provided on two of the four sides of the roughly rectangular first coarse porous layer 63a, when viewed in a plan view in the stacking direction, that are parallel to the direction of air flow (ventilation direction) of the air 49a. In other words, the coarse flow straightening wall portion 25c overlaps with the front flow straightening wall portion 25a of the first membrane (first CO2 separation membrane 60a) and the back flow straightening wall portion 25b of the second membrane (second CO2 separation membrane 60b). It is provided in such a manner. More specifically, the coarse flow straightening wall portion 25c is overlapped with the front flow straightening wall portion 25a of the first membrane and the back flow straightening wall portion 25b of the second membrane to form an outside air ventilation layer 24.

[0107] The second coarse porous layer 63b is a porous material installed between the second front ventilation layer 61b and the first back ventilation layer 62a. The fiber density of the second coarse porous layer 63b is lower than that of the second front ventilation layer 61b or the first back ventilation layer 62a. In other words, the second coarse porous layer 63b has better air permeability than the second front ventilation layer 61b and the first back ventilation layer 62a, and is less prone to pressure loss. The second coarse porous layer 63b is provided with a coarse flow straightening wall portion 25d.

[0108] The coarse flow-straightening wall portion 25d is provided on two of the four sides of the roughly rectangular second coarse porous layer 63b, when viewed in a plan view in the stacking direction, that are parallel to the direction of air flow (ventilation direction) of the air 39a. In other words, the coarse flow-straightening wall portion 25d is provided so as to overlap with the front flow-straightening wall portion 25a of the second membrane and the back flow-straightening wall portion 25b of the first membrane. More specifically, the coarse flow-straightening wall portion 25d overlaps with the front flow-straightening wall portion 25a of the second membrane and the back flow-straightening wall portion 25b of the first membrane to form an internal ventilation layer 23.

[0109] The porous material constituting the first coarse porous layer 63a and the second coarse porous layer 63b can be, for example, a nonwoven fabric or a mesh-like spacer.

[0110] Furthermore, as described above, in order to efficiently suppress the pressure loss in the air passages through which the internal and external air flow within the CO2 separation element 20b, it is desirable to determine the combination of porous materials used in each layer such that the pressure loss generated by the first coarse porous layer 63a is equal to or smaller than the pressure loss generated by the first front ventilation layer 61a and the second back ventilation layer 62b.

[0111] Similarly, in order to efficiently suppress pressure loss in the air passages through which internal and external air flow within the CO2 separation element 20b, it is desirable to determine the combination of porous materials used in each layer such that the pressure loss generated by the second coarse porous layer 63b is equal to or smaller than the pressure loss generated by the second front ventilation layer 61b and the first back ventilation layer 62a.

[0112] Furthermore, in order to miniaturize the CO2 separation element 20b, it is desirable that the vertical length (height) of the CO2 separation layer 22 be lower than the heights of the first front ventilation layer 61a, the first back ventilation layer 62a, the second front ventilation layer 61b, the second back ventilation layer 62b, the first coarse porous layer 63a, and the second coarse porous layer 63b.

[0113] Furthermore, if the pressure loss in the internal and external air passages within the CO2 separation element 20b increases, more energy will be required to secure the desired flow rates of the internal and external air. Therefore, in order to reduce the pressure loss in the internal and external air passages within the CO2 separation element 20b, it is desirable to make the height of the CO2 separation element 20b greater than the length of the internal and external air flow directions within the CO2 separation element 20b.

[0114] The CO2 separation element 20b according to Embodiment 3 of the present invention, as described above, has a structure in which a first CO2 separation membrane 60a, a first coarse porous layer 63a, a second CO2 separation membrane 60b, and a second coarse porous layer 63b are stacked in the vertical direction. As a result, the CO2 separation element 20b in this embodiment provides the same effects as the CO2 separation element 20a of Embodiment 2. In addition, the coarse porous layer is provided between the first CO2 separation membrane 60a and the second CO2 separation membrane 60b, which suppresses pressure loss in the air passages for the internal and external air. This allows internal and external air to circulate within the CO2 separation element 20b with less energy.

[0115] (Embodiment 4) Next, Embodiment 4 will be described with reference to Figure 7. Figure 7 shows an embodiment of the present invention. This is an exploded perspective view of the CO2 separation element related to 4. While the CO2 separation elements of Embodiments 1 to 3 are rectangular (square-shaped), the CO2 separation element in Embodiment 4 differs from Embodiments 1 to 3 in that it has a hexagonal shape. In the following description, components that are substantially the same as those in Embodiment 1 are denoted by the same reference numerals, and redundant explanations may be omitted or simplified. Also, the labels "up," "down," "left," and "right" in Figure 7 are included for the sake of explanation and are not intended to limit the actual orientation of the CO2 separation element 20c.

[0116] The CO2 separation element 20c is a laminated structure formed by stacking a CO2 separation layer 220, an internal air ventilation layer 230, and an external air ventilation layer 240. Although Figure 7 shows each layer individually for illustrative purposes, in reality, the CO2 separation element 20c is formed by stacking these layers multiple times, similar to embodiments 1 to 3.

[0117] The internal ventilation layer 230 has a hexagonal shape when viewed in a plan view in the stacking direction. The internal ventilation layer 230 is formed of a porous material such as a nonwoven fabric, and in this embodiment, it is an air passage through which air drawn in from the target space 2 (see Figure 1), i.e., internal air, flows. The internal ventilation layer 230 is equipped with a flow-straightening wall portion 250.

[0118] The rectifying wall portion 250 is provided on the side surfaces 203, 204, 205, and 206 of the internal ventilation layer 230, and suppresses the inflow and outflow of air through the side surfaces having the rectifying wall portion 250. In other words, the rectifying wall portion 250 determines the direction of airflow of the air 39a within the internal ventilation layer 230.

[0119] Air 39a flows into the CO2 separation element 20c from the side surface 201, separates the CO2 to the air 49a (outside air) side via the CO2 separation layer 220, and then blows out from the side surface 202, which is the surface opposite to the side surface 201.

[0120] The outside air ventilation layer 240 has a hexagonal shape when viewed in a plan view in the stacking direction. The outside air ventilation layer 240 is formed of a porous material such as a nonwoven fabric, and in this embodiment, it is an air passage through which air drawn in from outside, i.e., outside air, circulates. The outside air ventilation layer 240 is equipped with a flow straightening wall portion 260.

[0121] The rectifying wall portion 260 is provided on the side surfaces 303, 304, 305, and 306 of the outside air ventilation layer 240, and suppresses the inflow and outflow of air through the side surfaces having the rectifying wall portion 260. In other words, the rectifying wall portion 260 determines the direction of airflow of the air 49a within the outside air ventilation layer 240.

[0122] Air 49a flows into the CO2 separation element 20c from the side surface 301, receives CO2 from the air 39a (internal air) side via the CO2 separation layer 220, and then blows out from the side surface 302, which is the surface opposite to the side surface 301.

[0123] With this configuration, air 39a flows from left to right above the CO2 separation layer 220, and air 49a flows from right to left below the CO2 separation layer 220. In other words, the airflow directions of air 39a and air 49a are opposite each other, creating a counter-flow. This counter-flow between air 39a and air 49a across the CO2 separation layer 220 activates the separation of CO2 in the CO2 separation layer 22. As a result, it becomes possible to separate CO2 more efficiently.

[0124] Although the present invention has been described above based on embodiments, it can be easily inferred that the present invention is not limited in any way to the above embodiments, and that various improvements and modifications are possible without departing from the spirit of the present invention. For example, each embodiment, including the modifications described below, Each embodiment may be modified by adding or replacing some or more parts of the configuration of other embodiments with those of other embodiments. Furthermore, the numerical values ​​given in each embodiment are merely examples, and it is naturally possible to use other numerical values.

[0125] In the embodiments described above, the air 49a is configured to be outdoor (outside the building) air, but the system is not limited to this. For example, the air 49a may be configured to be air introduced from the ceiling inside the building, or indoor air from an adjacent room where no people are present may be introduced. In this way, air with a lower CO2 concentration than the air 39a in the target space 2 where people are present and the CO2 concentration has risen can be introduced into the CO2 separation element 20 as air 49a. Therefore, the same effect can be enjoyed in which CO2 moves from the air 39a with a high CO2 concentration to the air 49a with a relatively low CO2 concentration, thereby suppressing the rise in CO2 concentration in the target space 2. [Industrial applicability]

[0126] This invention is useful as a CO2 separation system and a CO2 separation element that can efficiently remove CO2 from a space with a large number of people. [Explanation of symbols]

[0127] 1 CO2 separation system 2. Target space 5. Control Unit 6. Laminated Structure 8. CO2 detection unit 10 cabinets 16 Internal air channel 17 Outside air passage 18 Carbon dioxide 19 Nitrogen 20, 20a, 20b, 20c CO2 separation elements 22, 220 CO2 separation layer 22a First CO2 separation layer 22b Second CO2 separation layer 22c Third CO2 separation layer 22d Fourth CO2 separation layer 22e Fifth CO2 separation layer 23, 230 Indoor ventilation layer 23a First Indoor Ventilation Layer 23b Second Indoor Ventilation Layer 23c Third Indoor Ventilation Layer 24, 240 Outdoor ventilation layer 24a First outdoor ventilation layer 24b Second outdoor ventilation layer 24c Third outside air ventilation layer 25, 250, 260 Rectification wall section 25a Front rectification wall 25b Back side rectification wall 25c, 25d Coarse flow straightening wall section 31 Internal fan 33 Indoor vent 35 Air supply port 37 Interior air filter 39a Air 39b Air 41 Outdoor fan 43. Outdoor air vent 45 Exhaust vent 47. Outdoor air filter 49a Air 49b Air 51 Indoor intake 52 Interior air intake duct 53 Indoor air outlet 54 Interior air outlet duct 55 Outdoor intake port 56. Outdoor air intake duct 57 Outdoor outlet 58. Outdoor air outlet duct 60a First CO2 separation membrane 60b Second CO2 separation membrane 61a First outer ventilation layer 61b Second outer ventilation layer 62a First back ventilation layer 62b Second back ventilation layer 63a First coarse porous layer 63b Second coarse porous layer 80 First Wind Route 90 Second wind path

Claims

1. CO installed between the first air passage and the second air passage ２ Separation layer, A ventilation layer forming the first air passage and the second air passage, It comprises a straightening wall section that determines the direction of airflow in the first air passage and the second air passage, The aforementioned ventilation layer is the CO ２ Supporting the separation layer, CO ２ Separation element.

2. The aforementioned CO ２ The separation layer and the ventilation layer are stacked alternately without gaps, forming CO ２ Separation element.

3. CO is a single structure ２ Formed by stacking separation membranes, The aforementioned CO ２ The separation membrane is The aforementioned CO ２ Separation layer, The CO ２ the ventilation layer formed on one side of the separation layer, and CO as described in claim 1 ２ Separation element.

4. CO is a single structure ２ Formed by stacking separation membranes, The aforementioned CO ２ The separation membrane is The aforementioned CO ２ Separation layer, The aforementioned CO ２ Formed on the surface of the separation layer, and the surface ventilation layer included in the ventilation layer, The aforementioned CO ２ The CO2 according to claim 1, comprising a back-side ventilation layer formed on the back surface of the separation layer and included in the ventilation layer. ２ Separation element.

5. The front ventilation layer and the back ventilation layer are rectangular in shape. The aforementioned outer ventilation layer is The two opposing sides of the rectangular shape are provided with front-side rectifying wall portions included in the rectifying wall portion, The aforementioned back ventilation layer is, The two sides, which are different from the aforementioned two sides, are provided with a rear side rectifying wall portion that is included in the rectifying wall portion. CO as described in claim 4 ２ Separation element.

6. The aforementioned CO ２ The separation membrane comprises a first membrane and a second membrane, The front-side rectifying wall portion in the first film is The second film is provided overlapping with the back-side rectifying wall portion, CO as described in claim 5 ２ Separation element.

7. CO in the stacking direction ２ The thickness of the separation layer is thinner than that of the ventilation layer, as described in claim 1. ２ Separation element.

8. A coarse ventilation layer is provided between the front ventilation layer of the first membrane and the back ventilation layer of the second membrane. The air permeability of the aforementioned coarse ventilated layer is Higher than the air permeability of the front ventilation layer and the back ventilation layer, CO as described in claim 6 ２ Separation element.

9. CO according to claims 1 to 8 ２ Separation SECWACO ２ Separation system.

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