Direct air capture module for carbon dioxide and direct air capture device for carbon dioxide

Abstract

Provided is a direct air capture module for carbon dioxide comprising a bag portion formed of two sheets each of which is made of a thermally weldable material, wherein the bag portion is formed by thermally welding a periphery of the bag portion, and wherein at least one of the two sheets is a microporous film. The microporous film comprises a thermoplastic polymer and has a gas permeability by having pores communicating with each other in the thickness direction so as to connect both main surfaces. The microporous film has a maximum pore diameter, measured in accordance with ASTM F316-03 (2019 re-approved version), ranging from 0.05 µm or more and less than 10 µm.

Description

DIRECT AIR CAPTURE MODULE FOR CARBON DIOXIDE AND DIRECT AIR CAPTUREDEVICE FOR CARBON DIOXIDETechnical Field

[0001] The present invention relates to a direct air capture module for carbon dioxide and a direct air capture apparatus for carbon dioxide.Background

[0002] In an effort to reduce global warming effects, there is significant effort underway to reduce carbon dioxide output, particularly with respect to exhaust gases from the energy and industrial sectors. Removal of carbon dioxide can take place at point sources (e.g., smokestacks) or in the atmosphere. Removal of carbon dioxide in the atmosphere is typically referred to as direct air capture (herein abbreviated “DAC”). A conventional carbon capture method can be found, for example, in Patent Document 1 (Japanese PCT Application Publication No. 2010-532710) which describes, as a technique for collecting carbon dioxide from combustion exhaust gas, “a sorbent fiber, comprising: a hollow fiber comprising a sorbent material; a lumen disposed within the hollow fiber; and a barrier layer lining the lumen to prevent fluid communication between the lumen and the sorbent material.”Summary

[0003] As compared to the capturing of carbon dioxide from the exhaust gas at the point source, DAC is characterized by: less restriction on the site of its implementation; ability to treat gas with a lower concentration of carbon dioxide (e.g., lower than 500 ppm); and, a low operating temperature (e.g., less than 110°C.).

[0004] In DAC, carbon dioxide is typically absorbed by a carbon dioxide absorbent (CO2 absorbent) under a relatively low temperature environment and released under a relatively high temperature environment. The absorbent can be in solid or liquid form. In one conventional DAC technique (see for example, Kikkawa et al., ACS Environ., Au 2022, 2, pp. 354 to 362) the absorbent is in solvent form and the solvent must be heated to release the absorbed carbon dioxide. Hence, there is room for improvement in the energy efficiency of these DAC devices and methods.

[0005] It is also conceivable to support the CO2 absorbent on a porous member. However, in such a configuration, diffusion is the rate-determining step in bringing the carrier gas of carbon dioxide and the CO2 absorbent into contact with each other. There is room for improvement in the rate of gas exchange (absorption and release of carbon dioxide) in these devices and methods.

[0006] Therefore, there is a need for development and improvement of DAC technology that addresses the unique environmental factors associated with capturing carbon dioxide from the atmosphere and improves upon the shortfalls of conventional DAC devices and methods.

[0007] The present disclosure provides a DAC module that includes a bag portion formed of two sheets each of which is made of a thermally weldable material, wherein the bag portion is formed by thermally welding a periphery of the bag portion. At least one of the two sheets comprises a microporous film. The microporous film comprises a thermoplastic polymer and has gas permeability by having poresthat communicate with each other in the thickness direction so as to connect both main surfaces. The microporous film has a maximum pore diameter, measured in accordance with ASTM F316-03 (2019 reapproved version), ranging from 0.05 pm or more and less than 10 pm.

[0008] The microporous film is a film that does not allow liquid to permeate therethrough but allows gas to permeate therethrough. A CO2 absorbent can be supported by the microporous film. In such a module, by allowing a gas to flow across the microporous film from one surface to the other, contact between the CO2 absorbent and the gas can be promoted so as to achieve an efficient gas exchange (absorption and release of carbon dioxide). Since the microporous film has pores substantially uniformly over the entire surface, the total surface area including the porous wall surfaces of the film is larger than that of a general nonwoven fabric or the like. A microporous film that supports substantially uniformly the CO2 absorbent can achieve extremely efficient and effective gas exchange (absorption and release of carbon dioxide). Since the module does not contain a large amount of solvent, the amount of heat required to release carbon dioxide can be reduced, and more energy efficient direct air capture of carbon dioxide can also be achieved. In addition, since the microporous film is inexpensive and can be thermally welded, there is also an advantage that the bag-shaped module can be easily manufactured at low cost.

[0009] In the bag-shaped module using the microporous film, it is not essential to make the module support the CO2 absorbent. The microporous film is impermeable to liquids but permeable to gases. By utilizing such characteristics, the microporous film can be used in combination with a CO2 absorbent that is in a solution state for the purpose of the direct air capture of carbon dioxide. Even in such a configuration, there are advantages that efficient contact between the gas and the CO2 absorbent can be realized and that a bag-shaped module can be easily manufactured at low cost.

[0010] In one embodiment, the present disclosure provides a direct air capture module for carbon dioxide comprising a bag portion formed of two sheets each of which is made of a thermally weldable material, wherein the bag portion is formed by thermally welding a periphery of the bag portion, wherein at least one of the two sheets is a microporous film, wherein the microporous film comprises a thermoplastic polymer and has gas permeability by having pores communicating with each other in the thickness direction so as to connect both main surfaces, and wherein the maximum pore diameter measured in accordance with ASTM F316-03 (2019 re-approved version) is 0.05 pm or more and less than 10 pm.

[0011] In another embodiment, the present disclosure provides a direct air capture apparatus for carbon dioxide comprising: the direct air capture module wherein a fluid inlet / outlet is disposed in the bag portion; and a housing for accommodating the direct air capture module for carbon dioxide, wherein the direct air capture module for carbon dioxide has a bag portion having a belt-like shape, wherein the fluid inlet / outlet extends perpendicularly to or parallel to the longitudinal direction of the belt-like shape, and wherein the direct air capture module for carbon dioxide is wound around an axis extending perpendicularly to or parallel to the longitudinal direction.

[0012] In a further embodiment, the present disclosure provides a direct air capture apparatus for carbon dioxide comprising: a heat exchanger having a plurality of fins; and a direct air capture modulefor carbon dioxide disposed on at least a portion of the plurality of fins, wherein one of the two sheets in the air capture module is a thermoplastic polymer film having an aluminum layer.

[0013] In yet a further embodiment, the present disclosure provides a method comprising: using one of the aforementioned direct air capture apparatus for carbon dioxide; supplying a gas to the bag portion or extracting a gas from the bag portion to cause the gas to flow across the microporous film; absorbing carbon dioxide from the gas at relatively low temperature using a carbon dioxide absorbent; and releasing carbon dioxide from the carbon dioxide absorbent and into the gas at a relatively high temperature.

[0014] The above summary of the present disclosure is not intended to describe each disclosed embodiment or every implementation of the present disclosure. The description that follows more particularly exemplifies illustrative embodiments.Brief Description of Drawings

[0015] FIG. 1 is a perspective cross-sectional view of an exemplary DAC module according to Embodiment 1 of the present disclosure;

[0016] FIG. 2 is a schematic plan view of the exemplary DAC module according to Embodiment 1 of the present disclosure;

[0017] FIG. 3 is a schematic cross-sectional view of an exemplary DAC module according to Modification 1 of Embodiment 1 of the present disclosure;

[0018] FIG. 4 is a schematic plan view of the exemplary DAC module according to Modification 1 of Embodiment 1 of the present disclosure;

[0019] FIG. 5 is a schematic cross-sectional view of an exemplary DAC module according to Modification 2 of Embodiment 1 of the present disclosure;

[0020] FIG. 6 is a schematic cross-sectional view of an exemplary DAC module according to Modification 3 of Embodiment 1 of the present disclosure;

[0021] FIG. 7 is a schematic cross-sectional view of an exemplary DAC module according to Modification 4 of Embodiment 1 of the present disclosure;

[0022] FIG. 8 is a schematic cross-sectional view taken along the x-y plane of an exemplary DAC module according to Embodiment 2 of the present disclosure;

[0023] FIG. 9 is a schematic cross-sectional view taken along the y-z plane of the exemplary DAC module according to Embodiment 2 of the present disclosure;

[0024] FIG. 10 is a schematic cross-sectional view taken along the x-y plane of an exemplary DAC apparatus according to Embodiment 2 of the present disclosure;

[0025] FIG. 11 is a schematic cross-sectional view taken along the y-z plane of an exemplary DAC apparatus according to Modification 1 of Embodiment 2 of the present disclosure;

[0026] FIG. 12 is a schematic cross-sectional view taken along the x-y plane of an exemplary DAC module according to Embodiment 3 of the present disclosure;

[0027] FIG. 13 is a schematic cross-sectional view taken along the y-z plane of the exemplary DAC module according to Embodiment 3 of the present disclosure;

[0028] FIG. 14 is a schematic cross-sectional view taken along the x-y plane of an exemplary DAC apparatus according to Embodiment 3 of the present disclosure;

[0029] FIG. 15 is a schematic cross-sectional view taken along the x-y plane of an exemplary DAC apparatus according to Modification 1 of Embodiment 3 of the present disclosure;

[0030] FIG. 16 is a schematic cross-sectional view taken along the x-y plane of an exemplary DAC apparatus according to Embodiment 4 of the present disclosure;

[0031] FIG. 17 is a schematic cross-sectional view taken along the y-z plane of the exemplary DAC apparatus according to Embodiment 4 of the present disclosure;

[0032] FIG. 18 is a schematic cross-sectional view of an exemplary DAC apparatus according to Embodiment 5 of the present disclosure;

[0033] FIG. 19 is a breakthrough curve obtained in a test example; and

[0034] FIG. 20 is a release curve obtained in a test example.

[0035] Unless otherwise indicated, all figures and drawings in this document are not to scale and are chosen for the purpose of illustrating different embodiments of the invention. In particular, the dimensions of the various components are depicted in illustrative terms only, and no relationship between the dimensions of the various components should be inferred from the drawings, unless so indicated.Detailed Description

[0036] In the following description of illustrative embodiments, reference is made to the accompanying figures of the drawing which form a part hereof, and in which are shown, by way of illustration, specific embodiments. It is to be understood that other embodiments may be utilized and structural changes may be made without departing from the scope of the present invention.

[0037] As used herein:

[0038] The term “comprises” and variations thereof do not have a limiting meaning where these terms appear in the description and claims. Such terms will be understood to imply the inclusion of a stated step or element or group of steps or elements but not the exclusion of any other step or element or group of steps or elements. By “consisting of’ is meant including, and limited to, whatever follows the phrase “consisting of.” Thus, the phrase “consisting of’ indicates that the listed elements are required or mandatory, and that no other elements may be present. By “consisting essentially of’ is meant including any elements listed after the phrase, and limited to other elements that do not interfere with or contribute to the activity or action specified in the disclosure for the listed elements. Thus, the phrase “consisting essentially of’ indicates that the listed elements are required or mandatory, but that other elements are optional and may or may not be present depending upon whether or not they materially affect the activity or action of the listed elements.

[0039] The terms “a,” “an,” and “the” are used interchangeably with “at least one” to mean one or more of the components being described.

[0040] The term “and / or” means one or all of the listed elements or a combination of any two or more of the listed elements.

[0041] The term “some embodiments” means that a particular feature, configuration, composition, or characteristic described in connection with the embodiment is included in at least one embodiment of the disclosure. Thus, the appearances of such phrases in various places throughout this specification are not necessarily referring to the same embodiment of the disclosure. Furthermore, the particular features, configurations, compositions, or characteristics may be combined in any suitable manner in one or more embodiments.

[0042] The terms “preferred” and “preferably” refer to embodiments of the disclosure that may afford certain benefits, under certain circumstances; however, other embodiments may also be preferred, under the same or other circumstances. Furthermore, the recitation of one or more preferred embodiments does not imply that other embodiments are not useful and is not intended to exclude other embodiments from the scope of the disclosure.

[0043] The term “thermal welding” refers to a technique to bond two objects made of resin or the like, including melting at least a part of the surface of each of the two objects by heating; and applying pressure to the objects. For the thermal welding, bonding by heat sealing, bonding by ultrasonic waves, bonding by high frequency waves, bonding by impulse sealer, or bonding by laser may be used. Depending on the location of the site to be welded, a gas-tight (no gas leakage through the joint) thermal welding may be selected.

[0044] The term “thermally weldable” means that the bonding can be achieved using the thermal welding technique, and specifically, for example, means that thermal welding can be achieved at a temperature ranging from 120°C to 300°C. The temperature used for the thermal welding varies depending on the materials to be bonded. The term “thermally weldable” may be used when thermal welding is possible at a temperature ranging from 120°C to 250°C, or ranging from 130°C to 200°C.

[0045] The term “sheet” and the term “film” are substantially synonymous and refer to a thin, flat, flexible member. The thickness of the “sheet” and the “film” may be more than 1 pm and less than 1000 pm, more than 5 pm and less than 800 pm, more than 10 pm and less than 600 pm, more than 15 pm and less than 400 pm, more than 20 pm and less than 200 pm, or more than 25 pm and less than 150 pm.

[0046] The term “gas permeability” means that the air permeability measured in accordance with ISO 5636-5:2003 (Gurley test method) is less than 500 seconds / 100 cc.

[0047] The term “direct air capture module for carbon dioxide” means a module that is suitable for use in direct air capture of carbon dioxide (DAC). Thus, even if a module is used for other carbon dioxide capture applications (e.g., capture at a source), the module is still a “direct air capture module for carbon dioxide” if the module is suitable for use in DAC.

[0048] FIG. 1 is a perspective cross-sectional view of an exemplary DAC module according to Embodiment 1 of the present disclosure. FIG. 2 is a schematic plan view of the exemplary DAC module according to Embodiment 1 of the present disclosure.

[0049] As shown in FIGS. 1 and 2, a DAC module 100 includes a first sheet 11 and a second sheet12, each of which is made of a thermally weldable material. A bag portion 13 is formed by thermally welding the first sheet 11 and the second sheet 12 around the bag portion 13. The portion where the firstsheet 11 and the second sheet 12 are thermally welded together constitutes a welded portion 14. In FIG. 1, the first sheet 11 and the second sheet 12 are each shown as a single sheet (a single-layer sheet) but may include two or more sheets (multiple-layer sheet). The first sheet 11 and the second sheet 12 are preferably airtight thermally welded, and the welded portion 14 is preferably an air-tight welded portion.

[0050] The bag portion 13 has a structure in which at least three sides are sealed by welding, and thus a fluid such as a gas supplied to the inside of the bag portion can be held therein to a certain extent. The shape of the bag portion 13 is not particularly limited, and may be rectangular, polygonal, elliptical, circular, indefinite, or the like. The bag portion 13 may be an envelope portion having an envelope-like shape (shape like a mailing envelope).

[0051] As shown in FIG. 2, the bag portion 13 may be sealed along the entire circumference. In this case, when the DAC module 100 is used, a fluid inlet / outlet (not shown) may be provided in the bag portion 13, and, for example, gas supply to the bag portion 13 or gas extraction from the bag portion 13 may be performed therethrough. One fluid inlet / outlet may be provided for one DAC module 100, or a plurality of fluid inlets / outlets may be provided therefor. In the latter case, the flow of the fluid within the bag portion 13 is easily made uniform.

[0052] A fluid flow pipe may be attached to an end portion of the DAC module 100, and a fluid inlet / outlet is provided in the fluid flow pipe and opens to the inside of the bag portion 13. A fluid may be supplied to the inside of the bag portion 13 or a fluid may be extracted therefrom through the fluid inlet / outlet. A single fluid flow pipe may be shared by multiple DAC modules. Such a configuration reduces the pressure loss inside the bag portion 13.

[0053] At least one of the first sheet 11 and the second sheet 12 is a microporous film (hereinafter referred to as “MPF”). The MPF is a film that is formed of a thermoplastic polymer, which has gas permeability because of the pores included therein and communicating with each other in a thickness direction so as to connect main surfaces on both sides. The maximum pore diameter of the pores ranges from 0.05 pm to 10 pm measured in accordance with ASTM F316-03 (2019 re-approved version).

[0054] Thermoplastic polymers include polyolefins, condensation polymers, and oxidation polymers. Polyolefins include, for example, polypropylene, high density polyethylene, low density polyethylene, polyvinyl-containing polymer, butadiene-containing polymer, acrylate-containing polymer, and the like. Condensation polymers include, for example, polyester, polyamide, polycarbonate, polysulfone, and the like. The oxidation polymer includes, for example, polyphenylene oxide and the like. Thermoplastic polymers also include polyvinyl chloride, nylon, polyester, PVDF (polyvinylidene fluoride), and the like.

[0055] In one embodiment, the MPF comprises polypropylene and an organic filler, and has a microsponge structure formed by micropores of 0.3 pm or less communicating with each other, which imparts to the microporous film both waterproofhess and moisture permeability. The MPF can have a thickness of 30 to 50 pm, a tensile strength in accordance with JIS P8113 of 5 to 10 N / cm in the longitudinal direction of the original film and 5 to 10 N / cm in the width direction of the original film, a tensile elongation in accordance with JIS P8113 of 200 to 400% in the longitudinal direction of theoriginal film and 200 to 400% in the width direction of the film, an air permeability in accordance with JIS P8117 of 20 to 400 seconds / 100 cc, and a moisture permeability in accordance with JIS L1099 of 5,000 to 20,000 g / m2-24 hours.

[0056] Other suitable MPFs and the methods for producing the same are described in detail, for example, in Japanese Patent Application Laid-Open No. Hl-101340 (corresponding to U.S. Patent No. 4,867,881), the content of which is incorporated herein by reference. The MPF disclosed in the document is a microporous article comprising a thermoplastic polymer structure having a multiplicity of cells. Channels are provided to connect adjacent cells in the structure so as to provide a network of interconnected pores. The cells consist of void spaces surrounded by fibrous, lacey, or semi-continuous boundaries and are ellipsoidal in shape. The structure is oriented (stretched) in at least one direction.

[0057] A MPF may be a microporous article comprising a thermoplastic polymer structure formed by thermally inducing liquid-liquid phase separation from a homogeneous solution comprising a thermoplastic polymer and a compatible liquid. The structure has a multiplicity of cells of which adjacent ones are connected by channels to provide a network of interconnected pores. The cells comprise void spaces contained by fibrous, lacey, or semi-continuous boundaries and may be ellipsoidal in shape. The structure may be oriented (stretched) in at least one direction. Orienting (stretching) may be carried out before or after the removal of at least a substantial portion of the compatible liquid.

[0058] A compatible liquid is a material that can form a solution with a thermoplastic polymer when heated to a temperature above the melting temperature of the thermoplastic polymer and, in addition, that when cooled, will phase separate from the polymer by liquid-liquid phase separation, rather than liquidsolid phase separation. The compatibility of the liquid with the polymer can be measured by heating the polymer and the liquid so as to form a clear homogeneous solution. If such a solution containing the polymer and the liquid cannot be formed at any liquid concentration, the liquid is unsuitable for use with the polymer. In fact, the liquid used for this purpose may be a compound which is solid at room temperature but liquid at the melting temperature of the polymer. The operability of a specific liquid for a given polymer cannot be predicted with absolute certainty. However, certain guidelines may be provided. For non-polar polymers, non-polar organic liquids having similar solubility parameters at room temperature are generally effective at the solution temperatures. Similarly, polar organic liquids are generally effective for polar polymers. When using a blend of a plurality of polymers, the effective liquid should be one that is a compatible liquid for each of the polymers used in the blend. If the polymer is a block copolymer such as styrene-butadiene block copolymer, the liquid to be selected must be compatible with each type of the polymer block. A blend of two or more different liquids can also be used as the compatible liquid, as long as the selected polymer is soluble in the liquid blend at the polymer melt temperature and the resulting solution separates by liquid-liquid phase separation upon cooling.

[0059] Various types of organic compounds have been found to be effective as the compatible liquids, including aliphatic and aromatic acids; aliphatic, aromatic, and cyclic alcohols; aldehydes; primary and secondary amines; aromatic and ethoxylated amines; diamines; amides; esters and diesters; ethers; ketones; and various hydrocarbons and heterocycles. When the polymer selected is polypropylene,esters such as dibutyl phthalate and ethers such as dibenzyl ether are useful as the compatible liquids. When high density polyethylene is the polymer, aliphatic ketones such as methyl nonyl ketone and esters such as dioctyl phthalate are useful as the compatible liquids. Some compatible liquids for use with low density polyethylene include aliphatic acids such as decanoic acid and oleic acid, and primary alcohols such as decyl alcohol. When the polymer selected is nylon 11, esters such as propylene carbonate, ethylene carbonate, and tetramethylene sulfone are useful as the compatible liquids. When the polymer selected is polymethylmethacrylate, some useful compatible liquids are 1,4-butanediol, lauric acid, and the like. A compatible liquid for use with polymeric polyphenylene oxide is, for example, tallowamine.

[0060] The MPF may have a density of 10 to 90% of the true density of the polymer of which it is made (i.e., without the micropores).

[0061] The maximum pore diameter of the MPF measured in accordance with ASTM F316-03 (2019 re-approved version) may be 0.05 pm or more and less than 10 pm, may be 0. 1 pm or more and less than 5 pm, may be 0.15 pm or more and less than 2 pm, or may be 0.2 pm or more and less than 1 pm.

[0062] The fact that the MPF has gas permeability by including pores communicating with each other in the thickness direction so as to connect the main surfaces on both sides can be confirmed by the fact that the maximum pore diameter measured in accordance with ASTM F316-03 (2019 re-approved version) is 0.05 pm or more. To put it differently, a maximum pore diameter, measured in accordance with ASTM F316-03 (2019 re-approved version), of 0.05 pm or more can be interpreted as the film including pores communicating with each other in the thickness direction so as to connect the main surfaces on both sides, which gives the gas permeability to the film.

[0063] The MPF does not include a nonwoven fabric. Nonwoven fabrics generally have a maximum pore diameter of 10 pm or more as measured in accordance with ASTM F316-03 (2019 re-approved version).

[0064] The gas permeability of the MPF is, for example, such that the air resistance measured in accordance with ISO 5636-5:2003 (Gurley test method) is more than 20 seconds / 100 mb and less than 500 seconds / 100 mb. The air permeability may be more than 50 seconds / 100 mb and less than 450 seconds / 100 mb, more than 80 seconds / 100 mb and less than 400 seconds / 100 mb, or more than 90 seconds / 100 mb and less than 300 seconds / 100 mb.

[0065] The MPF may be modified by application (deposition), absorption, impregnation, etc. of other materials. Such modification may be performed before or after the removal of the compatible liquid. The removal of the compatible liquid may be performed by a known method such as solvent extraction or volatilization. The carbon dioxide absorbent may be dissolved or dispersed in the compatible liquid remaining inside the pores, or may be attached as a liquid to the inner walls of the pores from which the compatible liquid has been removed.

[0066] The MPF may have the carbon dioxide absorbent by modification such as application (deposition), absorption, or impregnation, and may have the carbon dioxide absorbent inside the pores of the MPF. The MPF may have the carbon dioxide absorbent over its entire surface.

[0067] In some embodiments, the carbon dioxide absorbent is an amine-based absorbent. In the direct air capture of carbon dioxide, an operation is performed that absorbs carbon dioxide under a relatively low temperature environment and releases carbon dioxide under a high temperature environment. Hence, an amine-based absorbent that releases carbon dioxide at a temperature as low as possible and that has a small volatilized amount at that temperature, that is, having a low vapor pressure, can be suitably used. Specific examples thereof include monoethanol amine, l-(2-hydroxyethyl) piperazine, polyfunctional amines (e.g., hexamethylene diamine, dihexylamine, dioctylamine, trihexylamine, pentaethylene hexamine (PEHA), hexaethylene heptamine (HEHA), tetraethylene pentamine (TEPA), polyethylene imines (EPOMIN SP-003, SP-006, SP-012, SP-018, SP-200, HM-2000, P-1000, P-3000, all manufactured by Nippon Shokubai Co., Ltd.)), alkylamines having hydrophobic phenyl groups (e.g., benzyl amine, phenethyl amine, 4-methoxybenzylamine, 4- methoxytrifluorobenzylamine), diamines having aminocyclohexyl groups (specifically, for example, isophorone diamine [IPDA: 3-(aminomethyl)-3,5,5-trimethylcyclohexylamine], 4,4'-methylene bis(2- methylcyclohexylamine) (MBMCHA), trans- 1,2-diaminocyclohexane, 1,3-cyclohexanediamine, trans- 1,4-diaminocyclohexane), and the like.

[0068] An auxiliary agent for enhancing the carbon dioxide absorption performance of the amine or an additive for reducing oxidative deterioration may be blended. Examples of such an auxiliary agent include polyethylene glycol, diethanolamine, triethanolamine, 2-(2 -aminoethylamino) ethanol, and aminomethylpropanol, and examples of the anti-deterioration agent include 3,3'-dithiodipropionic acid.

[0069] In some embodiments, the carbon dioxide absorbent is a metal organic framework (MOF). In this case, the MOF may be added to the material (the solution containing the thermoplastic polymer and the compatible liquid) when the MPF is produced.

[0070] In the case where the MPF has a carbon dioxide absorbent, the method for supporting the carbon dioxide absorbent on the MPF is not particularly limited, and includes, as described above, modification of the MPF by application (deposition), absorption, impregnation, or the like, and addition of the carbon dioxide absorbent to the material during production of the MPF.

[0071] In a case where a certain substance chemically changes to a different substance by absorbing carbon dioxide and the different substance returns to the original substance by releasing carbon dioxide, the substances before and after the change are collectively referred to as a “carbon dioxide absorbent.”

[0072] The carbon dioxide absorbent used for modifying the MPF can be distributed on the wall surfaces of the pores of the MPF that communicate with each other in the thickness direction so as to connect the main surfaces on both sides. In this case, by passing the gas containing carbon dioxide through the MPF from one main surface to the other main surface, the gas containing carbon dioxide can be efficiently brought into contact with the carbon dioxide absorbent to make the carbon dioxide absorbent absorb carbon dioxide. In addition, by increasing the temperature while passing the carrier gas through the MPF from one main surface to the other main surface, fresh carrier gas having a low carbon dioxide concentration can be efficiently brought into contact with the carbon dioxide absorbent, and carbon dioxide can be efficiently extracted and released into the carrier gas.

[0073] At least one of the sheets 11, 12 is an MPF as described above. The other sheet may also be an MPF described above. Alternatively, the other sheet may be a thermo-plastic polymer fdm that is different from the above-described MPF, for example, a thermo-plastic polymer fdm having no gas permeability (e.g., a polyolefin film FLJ 386 (manufactured by 3M Japan Products), DIFARENB 1 BOTA (manufactured by DIC Corporation), Pylene film CT series (manufactured by Toyobo Co., Ltd.), a nonstretched polypropylene film FCMN (manufactured by Furamura Chemical Co., Ltd.), a non-stretched propylene film CP-GLC (manufactured by RM Tohcello Co., Ltd.)), or a thermoplastic polymer film having an aluminum layer (for example, Torayfan NO series (manufactured by Toray Advanced Film Co., Ltd.), PTP packaging material childproof and TOY AL LOTUS (both manufactured by Toyo Aluminium K. K.), ALT-PP (manufactured by Kanae Co., Ltd.), and the like).

[0074] When the gas is supplied to the bag portion 13, the inside of the bag portion 13 has a positive pressure, and the gas supplied to the inside of the bag portion 13 through a fluid inlet / outlet (not shown) provided in the bag portion 13 passes through (crosses) the MPF and flows out to the outside of the bag portion 13. When gas is extracted from the bag portion 13 through the fluid inlet / outlet, the inside of the bag portion 13 has a negative pressure, and the gas outside the bag portion 13 passes through (crosses) the MPF and flows into the inside of the bag portion 13.

[0075] As in a modification described later, the DAC module may include a spacer layer for facilitating the flow of the fluid inside and outside the bag portion 13. The spacer layer may be formed as a single member integrally with one of the first sheet 11 and the second sheet 12, or may be a separate member separated from the first sheet 11 and the second sheet 12.

[0076] In the present embodiment, the DAC module can be easily manufactured at low cost. By passing the gas through the MPF in a planar manner, the carbon dioxide absorbent and the gas can be efficiently brought into contact with each other, and thus the carbon dioxide can be efficiently absorbed and released.

[0077] In the present embodiment, when the MPF contains the carbon dioxide absorbent, the energy required for heating the solvent (water or the like) is further reduced. In addition, as the gas passes through the MPF, the carbon dioxide absorbent and the gas can be efficiently brought into contact with each other, and the carbon dioxide can be efficiently absorbed and released.

[0078] FIG. 3 is a schematic cross-sectional view of an exemplary DAC module according to a first modification of Embodiment 1 of the present disclosure. FIG. 4 is a schematic plan view of the exemplary DAC module according to the first modification of Embodiment 1 of the present disclosure.

[0079] As shown in FIG. 4, the DAC module 100A of Modification 2 is configured such that, in the DAC module 100 of Embodiment 1, a fluid inlet / outlet 17 is disposed in the bag portion 13, and a fluid flow pipe 18 is inserted into the fluid inlet / outlet 17. Since the configuration other than the fluid inlet / outlet 17 and the fluid flow pipe 18 is the same as that of the DAC module 100 of Embodiment 1, the same names and reference numerals as those used in Embodiment 1 are given to the common elements, and the detailed description thereof will be omitted.

[0080] The fluid inlet / outlet 17 is configured to supply a fluid from the outside to the inside of the bag portion 13 or to extract a fluid from the inside to the outside of the bag portion 13. More specifically, for example, the fluid inlet / outlet 17 may be an opening disposed in the welded portion 14. The fluid inlet / outlet 17 may be an opening disposed so as to pass from the first sheet 11 to the second sheet 12 in the cross-sectional direction within the bag portion 13.

[0081] The fluid flow pipe 18 may be, for example, a tube constructed of a thermally weldable material (e.g., a thermoplastic polymer). When the fluid flow pipe 18 is made of a material that can be thermally welded, the fluid flow pipe 18 can be fixed to the bag portion 13 easily and at low cost by thermal welding. The fluid flow pipe 18 and the bag portion 13 (the first sheet 11 and the second sheet 12) are preferably air-tightly thermally welded.

[0082] The fluid flow pipe 18 is open at both ends, with one end 19 disposed inside the bag portion 13 and the other end disposed outside the bag portion 13. In such a configuration, the fluid can be supplied from the outside to the inside of the bag portion 13 through the fluid flow pipe 18, or the fluid can be extracted from the inside to the outside of the bag portion 13 through the fluid flow pipe 18.

[0083] For example, in the case where the bag portion and the fluid flow pipe are integrated together, the opening of the fluid flow pipe may be used as the fluid inlet / outlet.

[0084] In the example shown in FIGS. 3 and 4, the fluid flow pipe 18 is inserted into the fluid inlet / outlet 17, but the fluid flow pipe 18 is not essential. A plurality of fluid inlet / outlets 17 (or a plurality of fluid flow pipes 18 inserted into the fluid inlet / outlets 17) may be provided. The fluid flow pipe 18 may have a plurality of openings located in the inside of the bag portion 13.

[0085] FIG. 5 is a schematic cross-sectional view of an exemplary DAC module according to Modification 2 of Embodiment 1 of the present disclosure.

[0086] As shown in FIG. 5, a DAC module 200 of Modification 2 is the DAC module 100 of Embodiment 1 further including a first spacer layer 15 between the first sheet 11 and the second sheet 12 and inside the bag portion 13. Since the configuration other than the first spacer layer 15 is the same as that of the DAC module 100 of Embodiment 1, the same names and reference numerals as those used in Embodiment 1 are given to the common elements, and the detailed description thereof will be omitted.

[0087] The first spacer layer 15 is disposed inside the bag portion 13 so as to be parallel to the first sheet 11 and the second sheet 12 and adjacent to the first sheet 11 and the second sheet 12. The first spacer layer 15 separates the first sheet 11 and the second sheet 12 from each other, forms a flow path of a fluid, and reduces resistance caused by the inner wall of the bag portion 13, thereby facilitating the flow of the fluid inside the bag portion 13. The first spacer layer 15 and at least one of the first sheet 11 and the second sheet 12 may be formed integrally together to be a single member.

[0088] The first spacer layer 15 may be made of a thermoplastic resin and fixed to at least one of the first sheet 11 and the second sheet 12 by thermal welding.

[0089] The first spacer layer 15 may be formed of a mechanical fastener (hook-and-loop fastener), a nonwoven fabric, a net (net-like member), or the like. The thickness of the spacer layer may be, forexample, greater than 0.01 mm and less than 5 mm, greater than 0.1 mm and less than 3 mm, greater than 0.2 mm and less than 2 mm, or the like.

[0090] Any known or unknown configuration can be adopted as the mechanical fastener. The mechanical fastener may be a dual hook type mechanical fastener formed by combining a hook material and a hook material, or may be a hook and loop type mechanical fastener formed by combining a hook material and a loop material, or may use only a single hook material (mechanical hook) or a single loop material (mechanical loop). In the present embodiment, the mechanical fastener is used also as a spacer layer for reducing the frictional resistance against the fluid inside the bag portion 13, and the function as a mechanical fastener for joining two members is not substantially used.

[0091] A part or the whole of the mechanical fastener may be made of a thermoplastic resin. Suitable thermoplastic resin include, but are not limited to, polyolefins, polyisoprenes, polybutadienes, fluorinated polymers, chlorinated polymers, polyamides, polyimides, polyethers, polyethersulfones, polysulfones, copolymers of polyvinyl acetate and vinyl acetate, such as polyethylene-co-polyvinyl alcohols, polyphosphazenes, polyvinyl esters, polyvinyl ethers, polyvinyl alcohols, and polycarbonates.

[0092] The mechanical fastener layer may be configured as a “fastening tape” in which a hook material or a loop material is provided on a substrate. The substrate may have a configuration having no gas permeability or may have a configuration having gas permeability.

[0093] Suitable materials for the substrate include, but are not limited to, polypropylenes, polyethylenes, polypropylene-polyethylene block copolymers, polyesters, vinyl chlorides, polyacetates, polyamides, cotton, and the like. These materials may be used alone or in combination of two or more kinds, and may be in the form of a sheet- or film-like shaped body, or may be in the form of a woven fabric, a nonwoven fabric, a knitted fabric, or the like. In particular, polypropylenes, polyethylenes, polypropylene-polyethylene copolymers, or a mixture thereof is suitable for use in disposable diapers because of its moderate flexibility and low cost. It is most preferable that the substrate is constituted of a shaped body comprising a mixture of a polypropylene resin and a polyethylene resin which is the same as or similar to the hook material so as to match the hook material.

[0094] Suitable materials for forming the hook material include, but are not limited to, resinous materials such as polypropylenes, polyethylenes, polypropylene-polyethylene block copolymers, polyesters, vinyl chlorides, polyacetates, polyamides, elastomers, and the like. In particular, polypropylenes, polyethylenes, polypropylene-polyethylene copolymers, polyesters, elastomers, or mixtures thereof are suitable for the implementation of the present invention.

[0095] The hook material usually has a structure in which a large number of hooks are integrally bonded to a support. The hooks may be arranged in an ordered manner or in a disordered manner on the support. The integral bonding of the hooks to the support may be achieved in various forms, for example, by simultaneous forming with the support, embedding or planting in the support, or bonding with an adhesive. Most preferred is integration by co-forming with the support. The shape of the hook is not particularly limited as long as it is entangled with the hook of the hook material or the loop of the loop material paired therewith to enable the desired fastening. As frequently used in this technical field,however, it is preferably a mushroom shape, a hook shape, a pin shape, or a shape of a protrusion similar thereto. The hook material can be produced by the method described in, for example, Japanese PCT Application Publication No. H6-500486, Japanese Patent Application Publication No. H8-508910, and the like.

[0096] In the hook material, the thickness of the support that supports the hooks may be in the range of 0.02 to 0.5 mm, or 0.04 to 0. 13 mm. The hook height can vary widely depending on the type of hook material desired, the thickness of the substrate, and other factors. The heights of the hooks (in other words, the sum of the height of the stems and the thickness of the heads formed at the tips of the stems, if any) are usually preferably adjusted to be as small and uniform as possible. The heights of the hooks are usually preferably in the range of about 0.1 to 1.3 mm, more preferably in the range of about 0.2 to 0.5 mm, as measured from its base.

[0097] The hooks are usually arranged on the support preferably at a population density of about 60 to 1,600 hooks / cm2, more preferably at a population density of about 125 to 700 hooks / cm2. The stem of each of the hooks has a base adjacent to the support, and the base preferably has a diameter ranging from about 0.1 to 0.6 mm, more preferably from about 0. 1 to 0.3 mm. The head of the hook may be of any shape and size.

[0098] When the hook material is used by being fastened to a substrate, a variety of fixing means can be used to fasten the hook material. Suitable means for fixing include adhesion by means of, for example, gluing, thermal fusion, or ultrasonic heating; integral forming, mechanical fastenings such as sewing and stapling, and the like.

[0099] The loop material is usually composed of a substrate and a loop provided on at least one surface of the substrate. The loop is not particularly limited as long as it has a function of engaging with the hook material, and therefore may be a loop body itself, or may be a loop-holding material such as a woven fabric or a nonwoven fabric. If desired, these loops may be used in combination or in the form of a laminate. The laminate can be formed by, for example, laminating the above-described loop onto a plastic fdm or the like. The loop material may be appropriately processed by raising, embossing, printing, dyeing, or the like.

[0100] The loop may be constructed of a variety of materials in a conventional manner. The fibrous material may be used in the form of, for example, a woven fabric, a non-woven fabric, a knitted fabric, or the like, depending on the desired shape of the loop. In addition, a film having fibers partially bonded thereon to form a bundle of fibers in a loop shape can be advantageously used as the loop.

[0101] Any of the loop engaging materials, apparatuses, devices, methods of manufacture, methods of use described in any of the following references (all of which are incorporated herein) can be used in any of the embodiments described herein: U.S. Pat. Nos. 8,777,919; 4,699,622; 4,894,060; 5,077,870; 5,312,387; 5,344,691; 5,399,219; 5,487,809; 5,537,722; 5,554,146; 5,705,013; 5,759,317; 5,851,205; 5,957,908; 5,985,081; 6,030,373; 6,051,094; 6,075,179; 6,190,758; 6,406,468; 6,544,245; 6,575,953; 7,032,278; 7,125,400; 7,361,246; 7,371,302; 7,517,572; 7,578,812; 7,658,813; 3,471,903; 4,120,718; 4,223,067; 4,216,257; 4,391,687; 4,322,875; 4,415,615; 4,454,183; 4,563,388; 3,353,663; 3,408,705;4,977,003; 4,679,851; 4,819,309; 4,776,636; 5,308,428; 5,135,598; 4,910,062; 4,887,339; 4,985,488; 5,679,302; 4,894,060; 5,145,929; 5,908,695; 5,024,880; 5,852,855; 5,040,275; 5,149,573;4,290,832; 5,453,319; 5,614,232; 5,691,027; 5,713,111; 5,671,512; 5,625,929; 5,671,511; 5,851,663; 5,654,487; 5,602,221; 5,598,610; 5,691,021; 7,879,441; 8,277,922; 6,470,540; 6,076,238; 6,592,800; 6,630,239;6,588,074; 7,217,455; 7,703,179; 6,874,777; 7,140,774; and United States Patent Application Publication No. 2004 / 0,010,217.

[0102] Any known or unknown configuration can be adopted as the nonwoven fabric. The nonwoven fabric may be made of thermoplastic fibers and fixed to at least one of the first sheet 11 and the second sheet 12 by thermal welding.

[0103] The nonwoven may have a basis weight of about 12 g / m2or greater. In one embodiment, the basis weight of the nonwoven layer is from about 15 g / m2to about 260 g / m2, from about 20 g / m2to about 230 g / m2, from about 25 g / m2to about 200 g / m2, from about 30 g / m2to about 150 g / m2, from about 35 g / m2to about 130 g / m2, from about 40 g / m2to about 130 g / m2, from about 50 g / m2to about 130 g / m2, from about 55 g / m2to about 130 g / m2, from about 60 g / m2to about 130 g / m2or from about 70 g / m2to about 130g / m2. The basis weight is calculated from the weight of a 10 cm x 10 cm sample.

[0104] In some embodiments, the nonwoven layer includes a nonwoven substrate. The nonwoven substrate may be a nonwoven fabric or nonwoven web manufactured by any of commonly known processes for manufacturing a nonwoven fabric or a nonwoven web. In the present disclosure, the term “nonwoven fabric (or nonwoven)” refers to a fabric having a structure of individual fibers or filaments, which is randomly and / or unidirectionally incorporated in a matte form but does not have an identifiable nature like a knitted fabric.

[0105] The nonwoven fabric or the nonwoven fabric web can be formed in a variety of processes, such as a meltblowing process, a spunbonding process, a spunlacing process, a bonded carded web process, an air laying process, and a wet laying process. In some embodiments, the nonwoven layer contains a multilayer nonwoven material, for example, having at least one layer of a meltblown nonwoven fabric and at least one layer of a spunbond nonwoven fabric, or any other suitable combination of nonwoven materials.

[0106] The fibrous materials providing useful nonwoven layers can be made of natural fibers (e.g., wood or cotton fibers), synthetic fibers (e.g., thermoplastic fibers), or a combination of natural and synthetic fibers.

[0107] Exemplary materials for forming thermoplastic fibers include polyolefins (e.g., polyethylenes, polypropylenes, polybutylenes, ethylene copolymers, propylene copolymers, butylene copolymers, and copolymers and blends of these polymers), polyesters, and polyamides.

[0108] The nonwoven substrate constituting the nonwoven layer may be formed from fibers or filaments made of any suitable thermoplastic polymer material. Suitable polymeric materials include, but are not limited to, polyolefins, polyisoprenes, polybutadienes, fluorinated polymers, chlorinated polymers, polyamides, polyimides, polyethers, polyethersulfones, polysulfones, copolymers of polyvinylacetate and vinyl acetate, such as polyethylene-co-polyvinyl alcohols, polyphosphazenes, polyvinyl esters, polyvinyl ethers, polyvinyl alcohols, and polycarbonates.

[0109] Suitable polyolefins include, but are not limited to, polyethylenes, polypropylenes, poly 1- butenes, copolymers of ethylene and propylene, alpha olefin copolymers (e.g., copolymers of ethylene or propylene with 1-butene, 1-hexene, 1-octene, and 1-decene), polyethylene-co-1 -butene, and polyethylene-co- 1 -butene-co- 1 -hexene.

[0110] The fibers may be, for example, multi-component fibers having a core of a thermoplastic material and a sheath of another thermoplastic material. The sheath may be melted at a lower temperature than the core. In such a case, exposing a mat of fibers to a sheath melt leaves a partial and random bonded portions among the fibers. A combination of different mono-component fibers having different melting points may also be useful for this purpose.

[0111] In some embodiments, a nonwoven fabric or nonwoven web useful in the nonwoven layer according to the present disclosure is at least partially elastic. Examples of polymers for making elastic fibers include thermoplastic elastomers such as ABA block copolymers, polyurethane elastomers, polyolefin elastomers (e.g., metallocene polyolefin elastomers), olefin block copolymers, polyamide elastomers, ethylene vinyl acetate elastomers, and polyester elastomers. ABA block copolymer elastomers are elastomers in which, generally, the A blocks are polystyrenic and the B block is prepared from a conjugated diene (e.g., lower alkylene diene). The A blocks are generally formed mainly from substituted (e.g., alkylated) or unsubstituted styrenic moieties (e.g., polystyrene, poly (alphamethylstyrene), or poly (t-butylstyrene)) and have a number average molecular weight from approximately 4,000 to 50,000 grams / mol. The B block is generally formed mainly from a conjugated diene (e.g., isoprene, 1,3 -butadiene, or ethylene -butylene monomer) that may be substituted or unsubstituted, and has a number average molecular weight from approximately 5,000 to 500,000 grams / mol. The A blocks and the B block may be configured in a linear, radial, or star-shaped configuration, for example. The ABA block copolymer may contain a plurality of A blocks and / or B blocks, and such blocks may be manufactured from the same monomer or different monomers. Typical block copolymers are linear ABA block copolymers in which the A blocks may be the same as or different from one another, or block copolymers having four or more blocks that predominantly stop with an A block. A multi-block copolymer may contain a certain proportion of an AB diblock copolymer that tends to form, for example, a more adhesive elastomer film segment. Other elastic polymers can be blended with block copolymer elastomers, and various elastic polymers may be blended to provide various degrees of elastic properties. A number of types of thermoplastic elastomers are commercially available, and examples thereof can include those commercially available from BASF (Florham Park, N.J.) under the trade name “STYROFLEX (™),” those commercially available from Kraton (™) Polymers (Houston, Tex.) under the trade name “KRATON (™),” those commercially available from Dow Chemical (Midland, Mich.) under the trade names “PELLETHANE (™),” “INFUSE (™),”“VERSIFY (™),” and “NORDEL (™),” those commercially available from DSM (Heerlen, Netherlands) under the trade name “ARNITEL (™),” those commercially available from E.I. DuPont de Nemours andCompany under the trade name “HYTREL (™),” and those commercially available from ExxonMobil (Irving, Tex.) under the trade name “VISTAMAXX (™)”, and others.

[0112] For example, the nonwoven web can be manufactured by carding, air laying, wet laying, spunlacing, spunbonding, electrospinning, or a melt blowing process such as meltspinning or meltblowing, or a combination thereof. Any of the nonwoven webs may be made from a single type of fiber or from two or more types of fibers different in thermoplastic polymer type, shape, and / or thickness, and the single fiber type or at least one of the plurality of fiber types may be a multicomponent fiber as described above.

[0113] Short fibers may also be present in the web. The presence of short fibers generally results in higher-loft (bulk) and lower-density webs than webs formed only from meltblown microfibers. Higher loft webs may have less cohesive force because of the interface present in the nonwoven layer or because of the bulk of the nonwoven layer itself. The less cohesive force allows the web to more easily be separated from one or more adhesive layers.

[0114] Optionally, the nonwoven layer may further include one or more layers of scrim. For example, though optionally, either or both of major surfaces of the nonwoven layer may further include a scrim layer. Scrims are typically reinforcements of woven or nonwoven fabrics made from fibers and are included in nonwoven articles to enhance their strength. Suitable scrim materials include, but are not limited to, nylon, polyester, fiberglass, polyethylene, polypropylene. Various average thicknesses are allowed for the scrim. The layer of scrim may optionally be bonded to the nonwoven substrate. Various adhesives can be used to bond the scrim to the nonwoven substrate. Alternatively, the scrim may be thermally bonded to the nonwoven fabric.

[0115] Each of useful nonwoven layers may have a suitable effective fiber diameter (EFD) desired for a particular application. In the present disclosure, the term “effective fiber diameter” is the diameter of fibers in a fibrous web, measured in accordance with an air permeation test where air at 1 atm and at room temperature is passed through a web sample of a specified thickness at a specified surface velocity (5.3 cm / sec), and the corresponding pressure drop is measured. Based on the pressure drop, the effective fiber diameter is calculated as described in Davies, C. N., The Separation of Airborne Dust and Particulates, Institution of Mechanical Engineers, London Proceedings, IB (1952). In some embodiments, the fibers of the nonwoven substrate have an effective fiber diameter from about 0. 1 pm to about 125 pm, from about 1 pm to about 75 pm, from about 2 pm to about 50 pm, from about 4 pm to about 35 pm, from about 4 pm to about 25 pm, from about 4 pm to about 20 pm, from about 4 pm to about 15 pm, from about 4 pm to about 10 pm, from about 4 pm to about 8 pm, or of about 6 pm. For example, the spunbond nonwoven layer typically has an effective fiber diameter of approximately 35 pm or less, while the air laid nonwoven layer may have a larger effective fiber diameter of approximately 100 pm.

[0116] The loft (bulk) of the nonwoven layer can be assessed in solidity. The solidity is determined by dividing the measured value of the bulk density of the nonwoven fibrous web by the density of the material constituting the solid portion of the web. The bulk density of the web can be determined by firstmeasuring the weight of the web (e.g., the weight of a 10 cm x 10 cm piece of the web). A measured value of the weight of the web is divided by an area of the web to obtain a basic weight of the web, which is expressed in the unit of g / m2. The thickness of the web can be measured by taking (e.g., by die cutting) a disc of a web having a diameter of 135 mm and then by measuring the web thickness in a state where a 230-g weight having a diameter of 100 mm is placed at the center of the web. The bulk density of the web is determined by dividing the basic weight of the web by the thickness of the web and is expressed in g / m3. The solidity is then determined by dividing the bulk density of the nonwoven fibrous web by the density of the material (e.g., polymer) containing solid filaments of the web. The bulk polymer density can be measured by standard means if the supplier does not identify the material density.

[0117] The loft is reported as 100% minus solidity (e.g., 7% solidity equals 93% loft). Higher loft is particularly advantageous for nonwoven layers that are pattern embossed. This is because the adhesive can flow infiltratively throughout the entire void volume relatively easily during application of thermal energy and / or pressure. In some embodiments, a high loft nonwoven layer can be bonded in an emboss- patteming process to make an array of required recessed portions.

[0118] The solidity of the nonwoven layer can be approximately from greater than 2.0% to less than 12.0% (i.e., the loft is approximately from less than 98.0% to greater than 88.0%). In some embodiments, the solidity of the nonwoven layer can be from approximately 5.0% to approximately 7.5%, from approximately 5.5% to approximately 7.0%, or from approximately 6% to approximately 6.5%.

[0119] As the net, for example, a net-shaped support selected from a resin net and a monofilament mesh (a monofilament knitted into a net shape) having a mesh size of 30 pm or more and 2,000 pm or less can be used. Since the flow path of the fluid changes depending on the shape of the net, the shape of the unit lattice of the net is selected from, for example, a square, a rectangle, a rhombus, a parallelogram, and the like depending on the purpose. A nonwoven fabric, a woven fabric, a knitted fabric, or the like can also be used as long as it has sufficient air permeability and stretch resistance against tensile stress.

[0120] Examples of the material of the net include resins such as polyethylenes, polyesters, polypropylenes, polyamides, polyphenylene sulfides, polystyrenes, PPS, PES, PEEK, PI, polycyclohexylenedimethylene terephthalate (PCT), polytetrafluoroethylene, polyether ether ketone, and polyvinylidene chloride, and inorganic materials such as ceramics, metals, and glass may be used. A nonwoven fabric, a woven fabric, a knitted fabric, or the like formed by using a fiber, a monofilament, a cord, or the like made of a resin or an inorganic material may also be used. A plurality of materials may be used in combination.

[0121] The net may be formed by any method, but a resin net obtained by extrusion forming is preferably used from the viewpoint of simplicity of the production method and uniformity of the mesh size. The extrusion-formed molded net is also available as a commercial product, and examples thereof include general-purpose commercially-available nets such as Naltex and Netron nets manufactured by Delstar Co., Ltd.

[0122] The net may have a single layer structure or a laminate structure of two or more layers. For example, the structure may be a laminate of a plurality of layers each of which is made of a nonwoven fabric, a woven fabric, or a net.

[0123] The shape and size of the first spacer layer 15 may be substantially the same as the shape and size of the bag portion 13. To be specific, for example, the first spacer layer 15 may have the same or substantially the same shape as the bag portion 13 in a state where the first sheet 11 and the second sheet 12 are in close contact with each other, but may be smaller than the size of the bag portion 13 in that state by more than 1 mm and less than 10 mm, more than 2 mm and less than 8 mm, or more than 3 mm and less than 7 mm in the vertical and horizontal directions in a plan view. In such a configuration, the region of the MPF that is in contact with the inside of the bag portion 13 can be effectively utilized to the maximum.

[0124] Modification 2 can reduce the frictional resistance to the fluid inside the bag portion 13. For example, the DAC module is particularly suitable when the inside of the bag portion 13 has a negative pressure, more specifically, when the DAC module is used in an aspect in which the gas that has passed through the MPF flows through the inside of the bag portion 13. Specifically, for example, the DAC module of Modification 2 can be suitably used in a basic operation 3, which is to be described later.

[0125] In this modification, the fluid inlet / outlet 17 (or the fluid flow pipe 18 inserted into the fluid inlet / outlet 17) can be disposed as described in Modification 1.

[0126] FIG. 6 is a schematic cross-sectional view of an exemplary DAC module according to Modification 3 of Embodiment 1 of the present disclosure. As shown in FIG. 6, a DAC module 300 of Modification 3 is the DAC module 100 of Embodiment 1 but further includes a second spacer layer 16 outside the bag portion 13. In FIG. 6, second spacer layer 16 is disposed so as to be adjacent to the first sheet 11, but the second spacer layer 16 may be disposed so as to be adjacent to the second sheet 12, or a plurality of second spacer layers 16 may be disposed so as to be adjacent to both the first sheet 11 and the second sheet 12. Since the configuration other than the second spacer layer 16 is the same as that of the DAC module 100 of Embodiment 1, the same names and reference numerals as those used in Embodiment 1 are given to the common elements, and the detailed description thereof will be omitted.

[0127] The second spacer layer 16 is disposed outside the bag portion 13 so as to be parallel to the first sheet 11 and the second sheet 12. The first sheet 11 (or the second sheet 12) adjacent to the second spacer layer 16 and the surface facing the first sheet 11 (or the second sheet 12) via the outside of the bag portion 13 (the second sheet 12 (or the first sheet 11) facing the second sheet 12 via the outside of the bag portion 13 when the DAC module 200 is wound) are separated from each other. The resistance caused by the outer wall of the bag portion 13 (and the surface facing the outer wall) is thus reduced, thereby facilitating the flow of the fluid outside the bag portion 13. The second spacer layer 16 and at least one of the first sheet 11 and the second sheet 12 adjacent thereto may be formed integrally to be a single member.

[0128] The shape and size of the second spacer layer 16 may be substantially the same as the shape and size of the first sheet 11, the second sheet 12, or the bag portion 13. In such a configuration, theregion of the MPF that is in contact with the inside of the bag portion 13 can be effectively utilized to the maximum.

[0129] In addition to the above-described configuration, the rest of the configuration of the second spacer layer 16 can be the same as that of the first spacer layer 15, and thus, detailed description thereof will be omitted.

[0130] Modification 3 can reduce the frictional resistance to the fluid outside the bag portion 13. For example, the DAC module is particularly suitable when the inside of the bag portion 13 has a positive pressure, more specifically, when the DAC module is used in an aspect in which the gas that has passed through the MPF flows through the outside of the bag portion 13. Specifically, for example, the DAC module 300 of Modification 3 can be suitably used in any one of basic operations 1 and 2, which are to be described later.

[0131] In this modification, the fluid inlet / outlet 17 (or the fluid flow pipe 18 inserted into the fluid inlet / outlet 17) can be disposed as described in Modification 1.

[0132] FIG. 7 is a schematic cross-sectional view of an exemplary DAC module according to Modification 4 of Embodiment 1 of the present disclosure.

[0133] As shown in FIG. 7, a DAC module 400 of Modification 4 is the DAC module 100 of Embodiment 1 further including: a first spacer layer 15 between the first sheet 11 and the second sheet 12 and inside the bag portion 13; and a second spacer layer 16 outside of the bag portion 13. Since the configuration other than the first spacer layer 15 and the second spacer layer 16 is the same as that of the DAC module 100 of Embodiment 1, the same names and reference numerals as those used in Embodiment 1 are given to the common elements, and the detailed description thereof will be omitted. The first spacer layer 15 may have the same configuration as that of Modification 2, and thus, detailed description thereof will be omitted. The second spacer layer 16 may have the same configuration as that of Modification 3, and thus the detailed description thereof will be omitted.

[0134] Modification 4 can reduce the frictional resistance to the fluid both inside and outside the bag portion 13. For example, the DAC module is suitable for a case where the inside of the bag portion 13 has a negative pressure, for a case where the inside of the bag portion 13 has a positive pressure, or for a case where the DAC module is used in a mode in which the negative pressure case and the positive pressure case are repeated. Specifically, for example, the DAC module 400 of Modification 4 can be suitably used in any of basic operations 1 to 3, which are to be described later.

[0135] In this modification, the fluid inlet / outlet 17 (or the fluid flow pipe 18 inserted into the fluid inlet / outlet 17) can be disposed as described in Modification 1.

[0136] Basic Operation 1 : Case of Using Liquid Carbon Dioxide Absorbent

[0137] As the liquid carbon dioxide absorbent, for example, a potassium hydroxide (KOH) aqueous solution is used.

[0138] In the case of removing carbon dioxide from the gas, for example, the gas (gas containing carbon dioxide at a relatively high concentration) is supplied into the bag portion 13 of the DAC module 100 and the KOH aqueous solution is caused to flow to the outside of the bag portion 13 under atemperature condition suitable for the KOH aqueous solution to absorb carbon dioxide. The gas passes through the MPF, flows out of the bag portion 13, and comes into contact with the KOH aqueous solution, whereby carbon dioxide in the gas is absorbed by the KOH aqueous solution. As a result, a gas containing a relatively low concentration of carbon dioxide is discharged from the apparatus. In the absorption of carbon dioxide, K2CO3 is generated by the reaction of the aqueous KOH solution with CO2. K2CO3 is reacted with Ca(OH)2 to generate CaCCh and KOH, so that CO2 can be fixed as CaC O ,.

[0139] In the case of releasing carbon dioxide, CO2 may be released by thermal decomposition of CaCO3.

[0140] For details of the DAC of carbon dioxide using a potassium hydroxide (KOH) aqueous solution, for example, see “Cost and Evaluation of Direct Air Capture (DAC) Method for Carbon Dioxide” (February 2020) edited by Center for Low Carbon Society Strategy of National Research and Development Agency, Japan Science and Technology Agency.

[0141] Since the MPF does not substantially allow liquid water to permeate therethrough, the KOH aqueous solution does not pass through the MPF and does not enter the inside of the bag portion 13. When used in Basic Operation 1, the MPF is preferably impermeable to water. If the moisture permeability is measured to be in the range of 10,000 to 40,000 g / m2-24 hours in accordance with the method of ISO 15496, the measured sample is determined to be water impermeable.

[0142] Basic Operation 2: Case 1 of Supporting Carbon Dioxide Absorbent on MPF (Inside of Bag Portion Having Positive Pressure)

[0143] As described above, the carbon dioxide absorbent such as IPDA is supported on the MPF by a known method such as coating or impregnation.

[0144] In the case of removing carbon dioxide from the gas, for example, the gas (the gas containing carbon dioxide at a relatively high concentration) is supplied to the inside of the bag portion 13 of the DAC module 100 under a temperature condition suitable for the carbon dioxide absorbent to absorb carbon dioxide (for example, a relatively low temperature). As the gas passes through the MPF and flows out to the outside of the bag portion 13, the gas comes into contact with the carbon dioxide absorbent supported on the MPF, whereby the carbon dioxide in the gas is absorbed by the carbon dioxide absorbent. As a result, the gas containing carbon dioxide at a relatively low concentration is extracted to the outside of the bag portion 13.

[0145] Conversely, in a case of releasing the carbon dioxide having been absorbed by the carbon dioxide absorbent, for example, under a temperature condition suitable for the carbon dioxide absorbent to release the carbon dioxide (for example, a relatively high temperature), a gas (a gas containing a relatively low concentration of carbon dioxide) is supplied to the inside of the bag portion 13 of the DAC module 100 via an inlet / outlet (not shown) for the fluid provided in the bag portion 13. As the gas passes through the MPF and flows out to the outside of the bag portion 13, the gas comes into contact with the carbon dioxide absorbent supported on the MPF, whereby carbon dioxide in the carbon dioxide absorbent is released into the gas. As a result, the gas containing the relatively high concentration of carbon dioxide is extracted to the outside of the bag portion 13.

[0146] Basic Operation 3: Case 2 of Supporting Carbon Dioxide Absorbent onMPF (Inside of Bag Portion Having Negative Pressure)

[0147] In the case where the carbon dioxide absorbent is supported on the MPF, the direction of gas flow may be opposite to that in the above-described Basic Operation 2. Specifically, in the case of removing carbon dioxide from the gas, for example, the gas (gas containing carbon dioxide at a relatively high concentration) is supplied to the outside of the bag portion 13 of the DAC module 100 under a temperature condition suitable for the carbon dioxide absorbent to absorb carbon dioxide (for example, a relatively low temperature), and the gas is sucked out of the inside of the bag portion 13 via an inlet / outlet (not shown) for the fluid provided in the bag portion 13. As the gas existing outside the bag portion 13 passes through the MPF and flows into the inside of the bag portion 13, and the gas comes into contact with the carbon dioxide absorbent supported on the MPF, whereby carbon dioxide in the gas is absorbed by the carbon dioxide absorbent. As a result, the gas containing carbon dioxide at a relatively low concentration can be extracted from the inside of the bag portion 13 through the inlet / outlet for the fluid.

[0148] In a case where the carbon dioxide having been absorbed by the carbon dioxide absorbent is released, a gas (a gas containing carbon dioxide at a relatively low concentration) is supplied to the outside of the bag portion 13 of the DAC module 100, for example, under a temperature condition suitable for the carbon dioxide absorbent to release carbon dioxide (for example, a relatively high temperature). The gas is sucked out from the inside of the bag portion 13 via an inlet / outlet (not shown) for a fluid provided in the bag portion 13. As the gas passes through the MPF and flows into the inside of the bag portion 13, the gas comes into contact with the carbon dioxide absorbent supported on the MPF, whereby carbon dioxide in the carbon dioxide absorbent is released into the gas. As a result, the gas containing carbon dioxide at a relatively high concentration can be extracted from the inside of the bag portion 13 through the inlet / outlet for the fluid.

[0149] Modifications of Basic Operations: Case 3 of Supporting Carbon Dioxide Absorbent on MPF

[0150] In Modifications of the basic operations, the direction of the gas flow can be reversed in the case of removing carbon dioxide from the gas and in the case of releasing carbon dioxide absorbed in the carbon dioxide absorbent. Specifically, for example, in the case of removing carbon dioxide from the gas, the operation can be performed in the same manner as in the Basic Operation 2, whereas in the case of releasing carbon dioxide absorbed by the carbon dioxide absorbent, the operation can be performed in the same manner as in the Basic Operation 3. Alternatively, for example, in the case of removing carbon dioxide from the gas, the operation may be performed in the same manner as in the Basic Operation 3, and in the case of releasing carbon dioxide absorbed by the carbon dioxide absorbent, the operation may be performed in the same manner as in the Basic Operation 2.

[0151] Configuration of Apparatus

[0152] FIG. 8 is a schematic cross-sectional view taken along the x-y plane of an exemplary DAC module according to Embodiment 2 of the present disclosure. FIG. 9 is a schematic cross-sectional view taken along the y-z plane of the exemplary DAC module according to Embodiment 2 of the presentdisclosure. FIG. 10 is a schematic cross-sectional view taken along the x-y plane of an exemplary DAC apparatus according to Embodiment 2 of the present disclosure.

[0153] As shown in FIGS. 8 and 9, a DAC module 500 of Embodiment 2 includes a first sheet 21 and a second sheet 22, each of which is made of a thermally weldable material. A bag portion 23 is formed by thermally welding the first sheet 21 and the second sheet 22 around the bag portion 23. The portion where the first sheet 21 and the second sheet 22 are thermally welded together constitutes a welded portion 24.

[0154] The first sheet 21, the second sheet 22, the bag portion 23, and the welded portion 24 can have the same configurations as the first sheet 11, the second sheet 12, the bag portion 13, and the welded portion 14 of Embodiment 1, and thus, detailed description thereof will be omitted. In the present embodiment, the MPF constituting at least one of the first sheet 21 and the second sheet 22 contains a carbon dioxide absorbent.

[0155] The DAC module 500 of Embodiment 2 has a belt-like shape (substantially rectangular parallelepiped shape) extending in the x-axis direction (longitudinal direction) when viewed from the y- axis direction. The fluid flow path 28 is attached to one end in the x-axis direction. The internal space of the bag portion 23 and the fluid flow path 28 communicate with each other through the fluid inlet / outlet 27. The shape of the fluid inlet / outlet 27 is not particularly limited. For example, the fluid flow path 28 may be formed in a tubular shape, and holes may be formed at predetermined intervals in the wall surface of the fluid flow path 28. The holes may be used as the fluid inlet / outlet 27. The fluid flow path 28 may be formed of a thermally weldable material, such as a thermoplastic polymer, and the first sheet 21 and the second sheet 22 may be thermally welded to the fluid flow path 28 in an airtight manner. As in Modification 1 of Embodiment 1, a tubular fluid flow pipe may be inserted into the bag portion 23 from the fluid inlet / outlet.

[0156] The DAC module 500 further includes, outside the bag portion 23, a spacer layer 26 for improving air permeability. The spacer layer 26 may have the same configuration as the second spacer layer 16 in Modifications 1 to 3 of Embodiment 1, and thus the detailed description thereof will be omitted.

[0157] As shown in FIG. 10, the DAC apparatus 550 of Embodiment 2 includes a cylindrical housing 30 extending in the z-axis direction, and a DAC module 500 disposed inside the housing 30 and wound around the fluid flow path 28 as a central axis parallel to the z-axis direction. To put it differently, in the example shown in FIG. 10, the fluid flow path 28 and the inlet / outlet 27 are formed so as to extend in a direction (z-axis direction) perpendicular to the longitudinal direction (x-axis direction) of the DAC module 500. The winding axis (z-axis direction) of the DAC module 500 extends perpendicular to the longitudinal direction (x-axis direction) of the DAC module 500.

[0158] In the x-y cross section, the bag portions 23 and the spacer layers 26 are alternately arranged in the radial direction from the central axis of the housing 30. As a result, the gas supplied to the bag portion 23 passes across (the MPF(s) constituting) the first sheet 21 and / or the second sheet 22, enters the external space of the bag portion 23 (the space where the spacer layer 26 is disposed), and is dischargedto the outside of the housing 30 through the fluid inlet / outlet (not shown) of the housing 30. Alternatively, the gas supplied to the internal space of the housing 30 through the fluid inlet / outlet (not shown) of the housing 30 passes through the spacer layer, passes across (the MPF(s) constituting) the first sheet 21 and / or the second sheet 22, enters the internal space of the bag portion 23, and flows into the fluid flow path 28 through the fluid inlet / outlet 27. The fluid flow path 28 penetrates through the wall of the housing 30, and the gas that has been flowed into the fluid flow path 28 may be discharged to the outside of the housing 30 through the fluid flow path 28.

[0159] In the present embodiment, the aspect ratio of the DAC module may be determined such that the longitudinal direction is the z-axis direction instead of the x-axis direction.

[0160] The operation method in Embodiment 2 can be the same as the above-described basic operation 2 (Case 1 of supporting the carbon dioxide absorbent on the MPF), the basic operation 3 (Case 2 of supporting the carbon dioxide absorbent on the MPF), and / or Modifications thereof.

[0161] Also in the present embodiment, the DAC module can be easily manufactured at low cost. The spacer layer reduces the frictional resistance of the fluid outside the bag portion and can suppress the pressure loss. Since the MPF contains the carbon dioxide absorbent, the energy required for heating the solvent (water or the like) is reduced. Furthermore, the gas passing through the MPF enables efficient contact between the carbon dioxide absorbent and the gas. As a result, efficient absorption and release of carbon dioxide are made possible.

[0162] FIG. 11 is a schematic cross-sectional view taken along the y-z plane of an exemplary DAC apparatus according to Modification 1 of Embodiment 2 of the present disclosure. Also in Modification 1, the configuration of the DAC module 500 may be the same as the configuration described above with reference to FIGS. 8 and 9 except that the longitudinal direction is the z-axis direction.

[0163] In a DAC apparatus 550A of Modification 1, the direction in which the cylindrical housing 30 extends is the x-axis direction. The DAC module 500 is wound around the welded portion 24 extending in the x-axis direction and located at the end portion of the DAC module 500 in the y-axis direction and is stored inside the housing 30. To put it differently, in the example shown in FIG. 11, the fluid flow path 28 and the inlet / outlet 27 are formed so as to extend in a direction parallel to the longitudinal direction (z-axis direction) of the DAC module 500. The winding axis (x-axis direction) of the DAC module 500 extends perpendicular to the longitudinal direction (z-axis direction) of the DAC module 500. When the x-axis direction is the vertical direction, the fluid flow path 28 and the inlet / outlet 27 may be disposed vertically below the DAC module 500 or vertically above the DAC module 500.

[0164] In the y-z cross section, the bag portions 23 and the spacer layers 26 are alternately arranged in the radial direction from the central axis of the housing 30. As a result, the gas supplied to the bag portion 23 passes across (the MPF(s) constituting) the first sheet 21 and / or the second sheet 22, enters the external space of the bag portion 23 (the space where the spacer layer is disposed), and is discharged to the outside of the housing 30 through the fluid inlet / outlet (not shown) of the housing 30. Alternatively, the gas supplied to the internal space of the housing 30 through the fluid inlet / outlet (not shown) of the housing 30 passes through the spacer layer, passes across (the MPF(s) constituting) the first sheet 21and / or the second sheet 22, enters the internal space of the bag portion 23, and flows into the fluid flow path 28 through the fluid inlet / outlet 27. The fluid flow path 28 penetrates through the wall of the housing 30, and the gas that has been flowed into the fluid flow path 28 may be discharged to the outside of the housing 30 through the fluid flow path 28.

[0165] The operation method in Modification 1 of Embodiment 2 can be the same as the abovedescribed Basic Operation 2 (Case 1 of supporting the carbon dioxide absorbent on the MPF), the Basic Operation 3 (Case 2 of supporting the carbon dioxide absorbent on the MPF), and / or Modifications thereof.

[0166] In the present modification, the aspect ratio of the DAC module may be determined such that the longitudinal direction is the x-axis direction instead of the z-axis direction.

[0167] In Embodiment 2 and in the modification thereof, the spacer layer 26 may be omitted. The fluid flow paths 28 and ports 27 may be located at the outermost portions of the wound DAC module.

[0168] The present modification also achieves the same effects as those described above in Embodiment 2. Further, in the present modification, the distance from the fluid inlet / outlet to the end portion on the opposite side thereof can be shortened in the bag portion, and the pressure loss inside the bag portion can be reduced.

[0169] FIG. 12 is a schematic cross-sectional view taken along the x-y plane of an exemplary DAC module according to Embodiment 3 of the present disclosure. FIG. 13 is a schematic cross-sectional view taken along the y-z plane of the exemplary DAC module according to Embodiment 3 of the present disclosure. FIG. 14 is a schematic cross-sectional view taken along the x-y plane of an exemplary DAC apparatus according to Embodiment 3 of the present disclosure.

[0170] As shown in FIGS. 12 and 13, the DAC module 600 of Embodiment 3 can have the same configuration as the DAC module of Embodiment 2 except that a spacer layer 25 for improving air permeability is provided inside the bag portion 23. Therefore, the same names and reference numerals are given to the corresponding components, and detailed description thereof will be omitted. In the present embodiment, the longitudinal direction of the DAC module 600 is the x-axis direction. The spacer layer 25 may have the same configuration as the first spacer layer 15 in Modifications 1 to 3 of Embodiment 1, and thus the detailed description thereof will be omitted. Also in the present embodiment, the MPF constituting at least one of the first sheet 21 and the second sheet 22 contains a carbon dioxide absorbent.

[0171] As shown in FIG. 14, the DAC apparatus 650 of Embodiment 3 includes a cylindrical housing 30 extending in the z-axis direction, and a DAC module 600 disposed inside the housing 30 and wound around the fluid flow path 28 as a central axis parallel to the z-axis direction. To put it differently, in the example shown in FIG. 14, the fluid flow path 28 and the inlet / outlet 27 are formed so as to extend in a direction (z-axis direction) perpendicular to the longitudinal direction (x-axis direction) of the DAC module 600. The winding axis (z-axis direction) of the DAC module 600 extends perpendicular to the longitudinal direction (x-axis direction) of the DAC module 600.

[0172] In the x-y cross-section, the bag portions 23 (and the spacer layers 25 inside the bag portions 23) and the spacer layers 26 are alternately arranged in the radial direction from the central axis of thehousing 30. As a result, the gas supplied to the bag portion 23 passes across (the MPF(s) constituting) the first sheet 21 and / or the second sheet 22, enters the external space of the bag portion 23 (the space where the spacer layer 26 is disposed), and is discharged to the outside of the housing 30 through the fluid inlet / outlet (not shown) of the housing 30. Alternatively, the gas supplied to the internal space of the housing 30 through the fluid inlet / outlet (not shown) of the housing 30 passes through the spacer layer 26, passes across (the MPF(s) constituting) the first sheet 21 and / or the second sheet 22, enters the internal space (i.e., the space where the spacer layer 26 is disposed) of the bag portion 23, and flows into the fluid flow path 28 through the spacer layer 25 and the fluid inlet / outlet 27. The fluid flow path 28 penetrates through the wall of the housing 30, and the gas that has been flowed into the fluid flow path 28 may be extracted to the outside of the housing 30 through the fluid flow path 28.

[0173] The operation method in Embodiment 3 can be the same as the above-described Basic Operation 2 (Case 1 of supporting the carbon dioxide absorbent on the MPF), the Basic Operation 3 (Case 2 of supporting the carbon dioxide absorbent on the MPF), and / or Modifications thereof.

[0174] In the present embodiment, the aspect ratio of the DAC module may be determined such that the longitudinal direction is the z-axis direction instead of the x-axis direction.

[0175] Also in the present embodiment, the DAC module can be easily manufactured at low cost. The spacer layer reduces the frictional resistance of the fluid both inside and outside the bag portion and can suppress the pressure loss. Since the MPF contains the carbon dioxide absorbent, the energy required for heating the solvent (water or the like) is reduced. Furthermore, the gas passing through the MPF enables efficient contact between the carbon dioxide absorbent and the gas. As a result, efficient absorption and release of carbon dioxide are made possible.

[0176] FIG. 15 is a schematic cross-sectional view taken along the x-y plane of an exemplary DAC apparatus according to Modification 1 of Embodiment 3 of the present disclosure. Also in Modification 1, the configuration of the DAC module 600 may be the same as the configuration described above with reference to FIGS. 12 and 13 except that the longitudinal direction is the z-axis direction. In a DAC apparatus 650A of Modification 1, the direction in which the cylindrical housing 30 extends is the x-axis direction. The DAC module 600 is wound around the welded portion 24 extending in the x-axis direction and located at the end portion of the DAC module 600 in the y-axis direction and is stored inside the housing 30. To put it differently, in the example shown in FIG. 15, the fluid flow path 28 and the inlet / outlet 27 are formed so as to extend in a direction parallel to the longitudinal direction (z-axis direction) of the DAC module 600. The winding axis (x-axis direction) of the DAC module 600 extends perpendicular to the longitudinal direction (z-axis direction) of the DAC module 600. When the x-axis direction is the vertical direction, the fluid flow path 28 and the inlet / outlet 27 may be disposed vertically below the DAC module 600 or vertically above the DAC module 600.

[0177] In the y-z cross-section, the bag portions 23 (and the spacer layers 25 inside the bag portions 23) and the spacer layers 26 are alternately arranged in the radial direction from the central axis of the housing 30. As a result, the gas supplied to the bag portion 23 (and to the spacer layer 25 located therein) passes across (the MPF(s) constituting) the first sheet 21 and / or the second sheet 22, enters the externalspace of the bag portion 23 (the space where the spacer layer 26 is disposed), and is discharged to the outside of the housing 30 through the fluid inlet / outlet (not shown) of the housing 30. Alternatively, the gas supplied to the internal space of the housing 30 through the fluid inlet / outlet (not shown) of the housing 30 passes through the spacer layer 26, passes across (the MPF(s) constituting) the first sheet 21 and / or the second sheet 22, enters the internal space (spacer layer 25) of the bag portion 23, and flows into the fluid flow path 28 through the fluid inlet / outlet 27. The fluid flow path 28 penetrates through the wall of the housing 30, and the gas that has been flowed into the fluid flow path 28 may be discharged to the outside of the housing 30 through the fluid flow path 28.

[0178] The operation method in Modification 1 of Embodiment 3 can be the same as the abovedescribed Basic Operation 2 (Case 1 of supporting the carbon dioxide absorbent on the MPF), the Basic Operation 3 (Case 2 of supporting the carbon dioxide absorbent on the MPF), and / or Modifications thereof.

[0179] In the present modification, the aspect ratio of the DAC module may be determined such that the longitudinal direction is the x-axis direction instead of the z-axis direction.

[0180] The present modification also achieves the same effects as those described above in Embodiment 3. Further, in the present modification, the distance from the fluid inlet / outlet to the end portion on the opposite side thereof can be shortened in the bag portion, and the pressure loss inside the bag portion can be reduced.

[0181] In Embodiment 3 and in the modification thereof, the spacer layer 26 may be omitted. The fluid flow paths 28 and ports 27 may be located at the outermost portions of the wound DAC module.

[0182] FIG. 16 is a schematic cross-sectional view taken along the x-y plane of an exemplary DAC apparatus according to Embodiment 4 of the present disclosure. FIG. 17 is a schematic cross-sectional view taken along the y-z plane of the exemplary DAC apparatus according to Embodiment 4 of the present disclosure.

[0183] The DAC module 700 in Embodiment 4 can have the same configuration as the DAC module 500 in Embodiment 2 except for the points that are to be described later. Therefore, similar names and reference numerals are given to the corresponding components, and detailed description thereof will be omitted.

[0184] As shown in FIGS. 16 and 17, the DAC apparatus 750 of Embodiment 4 includes a cylindrical housing 40 extending in the z-axis direction, and a DAC module 700 disposed inside the housing 40 and wound around the welded portion 14 formed on the opposite side of the fluid flow path 28 as a central axis parallel to the z-axis direction. In FIG. 16, three DAC modules 700 are disposed inside the single housing 40, but either a single DAC module 700 or a plurality of (i.e., two or more) DAC modules 700 may be disposed inside the single housing 40.

[0185] In the example shown in FIG. 16, the fluid flow path 28 and the inlet / outlet 27 are formed so as to extend in a direction (z-axis direction) perpendicular to the longitudinal direction (x-axis direction) of the DAC module 700. The winding axis (z-axis direction) of the DAC module 700 extends perpendicular to the longitudinal direction (x-axis direction) of the DAC module 700. The fluid flowpaths 28 of the plurality of DAC modules 700 disposed inside one housing 40 communicate with each other.

[0186] In the x-y cross section, the bag portions 23 and the spacer layers 26 are alternately arranged in the radial direction from the central axis of the housing 30. As a result, the gas supplied to the bag portion 23 passes across (the MPF(s) constituting) the first sheet 21 and / or the second sheet 22, enters the external space of the bag portion 23 (the space where the spacer layer 26 is disposed), and is discharged to the outside of the housing 30 through the fluid inlet / outlet (not shown) of the housing 30. In this embodiment, the MPF itself may not have a carbon dioxide absorbent.

[0187] The operation method in Embodiment 3 can be the same as the basic operation 1 (Case of using a liquid carbon dioxide absorbent). This will be described in more detail below with reference to FIG. 17.

[0188] In FIG. 17, the flow of the gas is indicated by the dashed-line arrows, and the flow of the liquid carbon dioxide absorbent is indicated by the solid-line arrows. Gas is supplied to the fluid flow path 28 through a gas port 41 located on the underside of the housing 40. The gas is further supplied to the internal space of the bag portion 23 through the inlet / outlet 27. Thereafter, the gas passes across (the MPF(s) constituting) the first sheet 21 and / or the second sheet 22 and flows out to the external space of the bag portion 23 (the space where the spacer layer 26 is disposed). The gas that has flowed out stays in the upper portion of the DAC module 700, passes, in the form of bubbles or the like, through the liquid carbon dioxide absorbent flowing down outside the bag portion of the DAC module 700. Then, the gas is discharged to the outside of the housing 40 through the gas inlet / outlet 42 disposed on the upper surface of the housing 40.

[0189] The liquid carbon dioxide absorbent is supplied into the inside of the housing 40 through a liquid inlet / outlet 43 disposed on the upper surface of the housing 40. The liquid carbon dioxide absorbent first stays on the uppermost DAC module 700, gradually flows down while passing through the spacer layer 26. Then, the liquid carbon dioxide absorbent stays on the middle and lower DAC modules 700, and flows down into the lowermost internal space of the housing 40 while passing through their respective spacer layers 26. Thereafter, the liquid carbon dioxide absorbent is discharged to the outside of the housing 40 through the liquid inlet / outlet 44 disposed on the lower surface of the housing 40.

[0190] In a case of absorbing carbon dioxide in a gas, the carbon dioxide is absorbed by the absorbent mainly while the gas is passing through the liquid. Since the pores of each MPF are distributed substantially uniformly over the entire main surfaces of the MPF, the gas also flows out substantially uniformly from the entire surfaces of the MPF(s) constituting the bag portion, to enable an efficient contact between the carbon dioxide absorbent and the gas.

[0191] In the present embodiment, the fluid flow path 28 may be used as the winding axis. The aspect ratio of the DAC module may be determined such that the longitudinal direction is the z-axis direction instead of the x-axis direction.

[0192] In the present embodiment, the DAC module can be easily manufactured at low cost. By passing the gas through the MPF in a planar manner, the carbon dioxide absorbent and the gas can beefficiently brought into contact with each other, and thus the carbon dioxide can be efficiently absorbed and released.

[0193] FIG. 18 is a schematic cross-sectional view of an exemplary DAC apparatus according to Embodiment 5 of the present disclosure.

[0194] As shown in FIG. 18, the DAC apparatus 800 includes a heat exchanger 50 having a plurality of fins 51, and a DAC module 200 disposed on at least a part of the fins 51. The DAC module 200 can have the same configuration as the DAC module 200 in Modification 1 of Embodiment 1 except for the points that are to be described later. Therefore, similar names and reference numerals are given to the corresponding components, and detailed description thereof will be omitted.

[0195] The DAC module 200 may be disposed on a part of the plurality of fins 51, or the DAC module 200 may be disposed on each of the plurality of fins 51.

[0196] In the DAC module 200, the first sheet 11 is an MPF and the second sheet 12 is a thermoplastic polymer film with an aluminum layer. The MPF has a carbon dioxide absorbent. In the DAC module 200, the aluminum layer side may be arranged to face the fins. The aluminum layer facilitates heat exchange between the DAC module 200 (and the gas therein) and the heat exchanger 50.

[0197] The heat exchanger 50 may have a known configuration, and thus a detailed description thereof is omitted. For example, a flow path through which a fluid heat medium flows may be formed on the inner side the wall portion 52 (on the left side thereof in FIG. 18) provided with the fins 51. The fins and the wall portion 52 can be typically made of a metal having a high thermal conductivity.

[0198] A gas containing carbon dioxide or a gas for receiving carbon dioxide can be supplied to the bag portion 13 through a fluid flow path (not shown) and a fluid inlet / outlet (not shown). The gas containing carbon dioxide or the gas for receiving carbon dioxide may be supplied to the outside of the bag portion 13 and may flow into the inside of the bag portion 13 through the MPF(s). In particular, in the latter case, it is preferable that a spacer layer be disposed in the inside of the bag portion 13. The heat exchanger 50 can be used to control the temperature of the DAC module 200, thereby controlling the absorption and release of carbon dioxide in the DAC module 200.

[0199] In the present embodiment, the spacer layer 15 may be omitted.

[0200] Also in the present embodiment, the DAC module can be easily manufactured at low cost. Since the MPF contains the carbon dioxide absorbent, the energy required for heating the solvent (water or the like) is reduced. The gas passing through the MPF enables efficient contact between the carbon dioxide absorbent and the gas. Furthermore, the radiator allows for efficient heating and cooling of the DAC module. As a result, efficient absorption and release of carbon dioxide are made possible.

[0201] Exemplary embodiments of the present disclosure will be described below.

[0202] [Clause 1]A direct air capture module for carbon dioxide comprising a bag portion formed of two sheets each of which is made of a thermally weldable material, wherein the bag portion is formed by thermally welding a periphery of the bag portion, wherein at least one of the two sheets is a microporous film,wherein the microporous film comprises a thermoplastic polymer and has gas permeability by having pores communicating with each other in the thickness direction so as to connect both main surfaces, and wherein the maximum pore diameter measured in accordance with ASTM F316-03 (2019 re-approved version) is 0.05 pm or more and less than 10 pm.

[0203] [Clause 2]The direct air capture module for carbon dioxide according to Clause 1, further comprising a spacer layer disposed adjacent to the sheets inside and / or outside the bag portion.

[0204] [Clause 3]The direct air capture module for carbon dioxide according to Clause 1, wherein a fluid inlet / outlet is disposed in the bag portion.

[0205] [Clause 4]The direct air capture module for carbon dioxide according to Clause 1, wherein the microporous film has a carbon dioxide absorbent.

[0206] [Clause 5]The direct air capture module for carbon dioxide according to Clause 1, wherein both of the two sheets are the microporous films.

[0207] [Clause 6]The direct air capture module for carbon dioxide according to Clause 1, wherein one of the two sheets is a thermoplastic polymer film having no gas permeability.

[0208] [Clause 7]The direct air capture module for carbon dioxide according to Clause 1, wherein one of the two sheets is a thermoplastic polymer film having an aluminum layer.

[0209] [Clause 8]The direct air capture module for carbon dioxide according to Clause 1, wherein the spacer layer comprises a mechanical fastener.

[0210] [Clause 9]The direct air capture module for carbon dioxide according to Clause 1, wherein the spacer layer comprises a nonwoven fabric.

[0211] [Clause 10]The direct air capture module for carbon dioxide according to Clause 1, wherein the spacer layer comprises a net.

[0212] [Clause 11]A direct air capture apparatus for carbon dioxide comprising the direct air capture module for carbon dioxide according to Clause 3; and a housing for accommodating the direct air capture module for carbon dioxide, wherein the direct air capture module for carbon dioxide has a bag portion having a belt-like shape,wherein the fluid inlet / outlet extends perpendicularly to or parallel to the longitudinal direction of the belt-like shape, wherein the direct air capture module for carbon dioxide is wound around an axis extending perpendicularly to or parallel to the longitudinal direction.

[0213] [Clause 12]A direct air capture apparatus for carbon dioxide comprising: a heat exchanger having a plurality of fins; and a direct air capture module for carbon dioxide according to Clause 7 disposed on at least a portion of the plurality of fins.

[0214] [Clause 13]A method comprising; using the direct air capture apparatus for carbon dioxide according to Clause 11 or Clause 12; supplying the gas to the bag portion or extracting a gas from the bag portion to cause the gas to flow across the microporous film; absorbing carbon dioxide from the gas at relatively low temperature using a carbon dioxide absorbent; and releasing carbon dioxide from the carbon dioxide absorbent and into the gas at a relatively high temperature.

[0215] [Clause 14]The method according to Clause 13, wherein the microporous film further comprises a carbon dioxide absorbent inside pores.

[0216] EXAMPLES

[0217] Preparation Example 1: Preparation of MPF Impregnated with Carbon Dioxide Absorbent

[0218] 15.0 g of isophorone diamine (IPDA) (manufactured by FUJIFILM Wako Pure ChemicalCorporation (Chuo-ku, Osaka)) were weighed out in a 225 mb glass bottle. Then 85.0g of isopropanol were added to the glass bottle and the resultant mixture was stirred with a stirrer for 5 minutes to obtain a clear IPDA liquid having a concentration of 15 wt.%.

[0219] A microporous film WHJ EX3697-3 (manufactured by 3M Japan Products, having a film thickness of 38 pm and an air permeability of 28 seconds / 100 cc measured in accordance with JIS P8117) was cut into pieces, each piece having an 18-cm width and a 70-cm length. A polyester film having a thickness of 50 pm, a length of 30 cm and a width of 100 cm was laid on a glass plate as a backing sheet for preventing contamination, and the cut-out MPF piece was placed thereon so as not to be wrinkled and fixed with an adhesive tape. The IPDA solution was dropped onto the MPF using a dropper, and the IPDA solution was applied using a #8 Meyer bar. The IPDA solution was absorbed into the MPF immediately after coating and penetrated to the opposite side of the film, resulting in a so-called impregnated state. The MPF impregnated with the IPDA solution was immediately peeled off from the polyester film backing, and suspended with its end fixed so that the MPF surface did not contact the wall surface, and air-dried for about 3 minutes. Thereafter, the resulting product was fixed to a corrugatedcardboard plate having a 20-cm width and a 70-cm length with an adhesive tape, and the corrugated cardboard plate was left to stand in an oven set at 65°C for 3 minutes to completely dry the isopropanol. The coated amount of the carbon dioxide absorber (IPDA) was 4.1 g / m2.

[0220] Preparation Example 2: Preparation of DAC Module

[0221] The DAC module is composed of a plurality of components, and four sides thereof were heat-sealed to form a bag portion.

[0222] From the MPF impregnated with a carbon dioxide absorbing agent (IPDA), which was prepared by the method of Preparation Example 1, three pieces were cut out, each of which has a rectangular shape having a 15-cm vertical side and a 28-cm horizontal side. In addition, a film with an aluminum layer (three-layer structure of PET [16 pm] / aluminum [7 pm] / PP [40 pm], manufactured by Kanae Co., Ltd., (Chuo-ku, Osaka city)) that can be heat-sealed to the MPF was cut into a rectangle having the same size as the MPF (i.e., having a vertical side of 15 cm and a horizontal side of 28 cm).

[0223] A polypropylene nonwoven fabric (Eltas P03020, manufactured by M. A. Life Materials (Chuo-ku, Tokyo)) having a thickness of 105 pm was cut into a rectangular shape having a vertical side of 12 cm and a horizontal side of 24 cm, and used as a spacer to be disposed inside the bag portion. A mechanical hook (1600DH manufactured by 3M Japan Products Co., Ltd.,(Shinagawa-ku, Tokyo)) having a thickness of 370 pm (a pin height of 275 pm and a base film thickness of 85 pm) was cut into a rectangle having a vertical side of 14 cm and a horizontal side of 20 cm, and used as a spacer to be disposed outside the bag portion.

[0224] A polypropylene tube (UP tube UPP-4 x 3. manufactured by Ushio Lighting (Chuo-ku, Tokyo)) having an outer diameter of 4 mm cp was cut to a length of 15 cm to be used as a fluid flow pipe. A polypropylene tube (manufactured by Alam Co., Ltd., (Kita-ku, Osaka)) having an outer diameter of 15 mm cp was cut to a length of the 15 cm to be used as a core around which the bag portion was wound.

[0225] For the heat-sealing, an impulse sealer Fa-300-10 (manufactured by Fuji Impulse Co., Ltd., (Toyonaka-City, Osaka)) having a seal width of 10 mm was used. The heat-sealing conditions (temperature, sealing time, etc.) were set to optimum conditions in accordance with the thickness of the film to be heat-sealed, the number of sheets to be heat-sealed, etc. For the preparation of bags using MPF, usually, the conditions of vol. 6 (sealing time: 0.6 seconds) were used, and when heat sealing was insufficient, the conditions of vol. 7 (sealing time: 0.7 seconds) or vol. 8 (sealing time: 0.8 seconds) were used.

[0226] The fluid flow pipe was temporarily fixed with an adhesive tape at a position approximately 3 cm inside from the lateral end of the film with an aluminum layer, in parallel with the lateral end of the film, so that the end of the tube was located at the center of the film (at a position approximately 7 cm from the upper side). The end of the tube and the upper side of the heat seal film were heat-sealed to fix the tube to the film with an aluminum layer.

[0227] The polypropylene nonwoven fabric was placed on the film with an aluminum layer so that the entire polypropylene nonwoven fabric was placed on the film and the end portion of thepolypropylene nonwoven fabric was positioned immediately inside the tube. Then, the end portion was fixed to the film with an aluminum layer by heat-sealing.

[0228] Three MPFs were stacked one upon the other so that the outer peripheries thereof coincided with those of the film with an aluminum layer, and the left side, the lower side, and the right side were bonded by heat-sealing. Finally, the upper side was heat-sealed to complete the sealing of the bag portion, and then each of the heat-sealed portions was cut off by about 3 to 5 mm.

[0229] The bag was immersed in water and air was supplied to visually check that gas flowed out in a foam-like form from the entire main surfaces of the bag, thereby confirming that there was no substantial leakage in the heat sealed portions including the surrounding portions of the fluid flow pipe.

[0230] The mechanical hook was placed on the bag portion so that the pin faced the MPF side, and the left end of the mechanical hook was fixed to the left end of the bag portion with an adhesive tape. After the left end was fixed to the core with an adhesive tape, the bag was wound around the core, and the end of the bag portion at the outermost periphery was fixed with a rubber band so as not to be unwound.

[0231] The roll-shaped module was housed in a housing made of a stainless steel pipe having a 38 mm cp to complete a DAC apparatus.

[0232] Preparation Example 3: Preparation of Nonwoven Fabric Coated with Carbon Dioxide Absorbent (Comparative Example)

[0233] As a comparative example, a spunbond nonwoven fabric PMA020 having a 20-g / m2 basis weight manufactured by MA Life Materials, Co., Ltd. (Chuo-ku, Tokyo, Japan) was used. The IPDA solution was applied to the nonwoven fabric and dried in the same manner as in Example 1.

[0234] Test Example 1 : Absorption of Carbon Dioxide (by DAC)

[0235] The performance of the prepared direct air capture module for capturing carbon dioxide was evaluated by passing pure nitrogen gas or a blended gas of carbon dioxide and nitrogen having a specified concentration through the module at a constant flow rate and then by measuring the concentration of carbon dioxide contained in the gas that was discharged. The carbon dioxide concentration was measured using an FT-IR spectrophotometer (iS50, manufactured by Thermo Fisher Scientific Inc. (Minato-ku, Tokyo)). A gas cell for measuring gas samples was installed, and the gas to be measured was introduced into the cell at a flow of 150 mL / min. The carbon dioxide concentration was calculated using a calibration curve prepared in advance using a blend gas of carbon dioxide and nitrogen having known concentrations.

[0236] The absorption of carbon dioxide was carried out by passing a blend gas of carbon dioxide and nitrogen (with a carbon dioxide concentration of 1.0%) at room temperature through the module. The prepared roll-shaped module was introduced into a stainless-steel housing, caps were attached to both ends, and the roll-shaped module was connected to a nylon tube pipe having a diameter of 6 mm cp. For the first three minutes, pure nitrogen was introduced to replace the air in the housing and the pipe with nitrogen. The gas introduced into the housing was then switched to a blend gas of carbon dioxide and nitrogen gas, and the gas was passed through the module at a flow rate of 150 mL / min. Then, the carbondioxide concentration was measured of the gas that had passed through the module. The resulting breakthrough curve is shown in FIG. 19 (IPDA).

[0237] Test Example 2 : Release of Carbon Dioxide

[0238] The prepared roll-shaped module was introduced into a stainless-steel housing, caps were attached to both ends, and the roll-shaped module was connected to a nylon tube pipe having a diameter of 6 mm cp. The module was saturated with carbon dioxide by passing air through the module overnight. Thereafter, pure nitrogen was introduced for the first 3 minutes to replace the air in the pipe with nitrogen. The stainless-steel housing was immersed in warm water set to a temperature ranging from 70°C to 75°C while the flow amount of pure nitrogen was kept at 150 mL / min. Thus, the temperature of the entire module was raised, and the measurement of the carbon dioxide concentration was started for the gas that had passed through the module. The measurement was performed at intervals of 20 seconds and 4 scans were performed, and this was continued for 3 hours. Measurement results are shown in FIG. 20 (IPDA).

[0239] Test Example 3 : Case of Using MBMCHA as Carbon Dioxide Absorbing Agent

[0240] A MBMCHA liquid having a concentration of 15% was prepared using 4,4’ -methylene bis(2-methylcyclohexylamine) [MBMCHA] (manufactured by Tokyo Kasei Kogyo Co., Ltd. (Chuo-ku, Tokyo)) as a carbon dioxide absorber, and the carbon dioxide absorber was applied to MPF in the same manner as in Preparation Example 1. The coating weight of the carbon dioxide absorber after drying with isopropanol was 4.6 g / m2. Using the film, a roll-shaped module was prepared in the same manner as in Preparation Example 2.

[0241] The performance of the roll-shaped direct air capture module for carbon dioxide was evaluated in the same manner as in Test Examples 1 and 2. FIGS. 19 (MBMCHA) and 20 (MBMCHA) show the results.

[0242] Test Example 4 : Case of Using TEPA as Carbon Dioxide Absorbing Agent

[0243] A TEPA solution having a concentration of 15% was prepared using tetraethylenepentamine[TEPA] (manufactured by FUJIFILM Wako Pure Chemical Corporation (Chuo-ku, Osaka)) as a carbon dioxide absorbent. The carbon dioxide absorbent was then applied to the MPF in the same manner as in Preparation Example 1. The coating weight of the carbon dioxide absorber after drying with isopropanol was 6.7g / m2. Using the film, a roll-shaped module was prepared in the same manner as in Preparation Example 2.

[0244] The performance of the roll-shaped direct air capture module for carbon dioxide was evaluated in the same manner as in Test Examples 1 and 2. FIGS. 19 (TEPA) and 20 (TEPA) show the results.

[0245] Test Example 5: Performance of Retaining Carbon Dioxide Absorbent

[0246] The MPF impregnated with IPDA prepared in Preparation Example 1 and a 100 pm -thick polyester film (Lumirror #100-S10 manufactured by Toray Industries, Inc. (Chuo-ku, Tokyo)) were cut into a piece of 10 cm * 10 cm size and a piece of 11 cm x 11cm size, respectively. A laminate in which six polyester films and 5 MPF films were alternately laid one upon the other was placed on a flataluminum plate having a thickness of 5 mm (manufactured by Misumi Co., Ltd. (Chiyoda-ku, Tokyo)). A glass plate was placed on the uppermost polyester film, and a 1,000-g weight was placed thereon to apply pressure, and the laminate was allowed to stand in an oven set at 80°C for 24 hours. Thereafter, the laminate was cooled at room temperature for 1 hour to visually check the degree of transfer of the carbon dioxide absorbent to the polyester film. Few foreign matters were found on the surface of the polyester film, and almost all the carbon dioxide absorbent was retained by the MPF.

[0247] The nonwoven fabric coated with IPDA prepared in Preparation Example 3 and a 100 pm- thick polyester film (Lumirror #100-S10, manufactured by Toray Industries, Inc. (Chuo-ku, Tokyo)) were cut into a piece of 10 cm x 10 cm size and a piece of 11 cm x 11cm size, respectively. A laminate in which six polyester films and 5 MPF films were alternately laid one upon the other was placed on a flat aluminum plate having a thickness of 5 mm (manufactured by Misumi Co., Ltd. (Chiyoda-ku, Tokyo)). A glass plate was placed on the uppermost polyester film, and a 1,000-g weight was placed thereon to apply pressure, and the laminate was allowed to stand in an oven set at 80°C for 24 hours. Thereafter, the laminate was cooled at room temperature for 1 hour to visually check the degree of transfer of the carbon dioxide absorbent to the polyester film. A white transferred object was observed on the surface of the polyester film. The white transferred object was thought to be carbamate generated by the reaction of IPDA with carbon dioxide in the air.

[0248] Results

[0249] In the cases where any of IPDA, MBMCHA, and TEPA was used as the carbon dioxide absorbent, the obtained modules were able to absorb carbon dioxide at room temperatures and release carbon dioxide at a temperature ranging from 70°C to 75°C. To put it differently, it was confirmed that the obtained modules had characteristics suitable as DAC modules.

[0250] It was also confirmed that the MPF had a higher retention performance of the carbon dioxide absorbent (that is, the absorbent was less likely to exude) than the nonwoven fabric. In this respect, it was understood that the modules using the MPF had a characteristic suitable for the DAC modules. However, in the working examples, the high retention performance of the carbon dioxide absorbent is not an essential effect.

[0251] Remarks

[0252] The entire disclosures of all patents, patent applications and publications, other kinds of publications, and electronically available materials cited herein are incorporated by reference. In the event of any inconsistencies between the disclosure content of the present application and the disclosure content of any document incorporated herein by reference, the disclosure content of the present application has a higher priority. The above embodiments and examples are only illustrated for clarity of understanding. No unnecessary limitation should be understood from the above embodiments and examples. The present disclosure is not limited to the exact details illustrated and described, but variations which are obvious to one skilled in the art are included within the scope defined by the claims and the doctrine of equivalents.

[0253] All item names are for the convenience of the reader and should not be used to limit the meaning of the text following the item name, unless so identified.

[0254] Various modifications can be made without departing from the spirit and scope of the present invention. These and other embodiments are intended to be included within the scope defined by the following claims and the doctrine of equivalents.

Claims

What is claimed is:

1. A direct air capture module for carbon dioxide comprising a bag portion formed of two sheets each of which is made of a thermally weldable material, wherein the bag portion is formed by thermally welding a periphery of the bag portion, wherein at least one of the two sheets is a microporous fdm, wherein the microporous fdm comprisesa thermoplastic polymer and has gas permeability by having pores communicating with each other in the thickness direction so as to connect both main surfaces, and wherein the maximum pore diameter measured in accordance with ASTM F316-03 (2019 re-approved version) is 0.05 pm or more and less than 10 pm.

2. The direct air capture module for carbon dioxide according to Claim 1, further comprising a spacer layer disposed adjacent to the sheets inside and / or outside the bag portion.

3. The direct air capture module for carbon dioxide according to Claim 1, wherein a fluid inlet / outlet is disposed in the bag portion.

4. The direct air capture module for carbon dioxide according to Claim 1, wherein the microporous fdm has a carbon dioxide absorbent.

5. The direct air capture module for carbon dioxide according to Claim 1, wherein both of the two sheets are the microporous fdms.

6. The direct air capture module for carbon dioxide according to Claim 1, wherein one of the two sheets is a thermoplastic polymer fdm having no gas permeability.

7. The direct air capture module for carbon dioxide according to Claim 1, wherein one of the two sheets is a thermoplastic polymer fdm having an aluminum layer.

8. The direct air capture module for carbon dioxide according to Claim 1, wherein the spacer layer comprises a mechanical fastener.

9. The direct air capture module for carbon dioxide according to Claim 1, wherein the spacer layer comprises a nonwoven fabric.

10. The direct air capture module for carbon dioxide according to Claim 1, wherein the spacer layer comprises a net.

11. A direct air capture apparatus for carbon dioxide comprising: the direct air capture module for carbon dioxide according to Claim 3; and a housing for accommodating the direct air capture module for carbon dioxide, wherein the direct air capture module for carbon dioxide has a bag portion having a belt-like shape, wherein the fluid inlet / outlet extends perpendicularly to or parallel to the longitudinal direction of the belt-like shape, wherein the direct air capture module for carbon dioxide is wound around an axis extending perpendicularly to or parallel to the longitudinal direction.

12. A direct air capture apparatus for carbon dioxide comprising: a heat exchanger having a plurality of fins; and a direct air capture module for carbon dioxide according to Claim 7 disposed on at least a portion of the plurality of fins.

13. A method comprising; using the direct air capture apparatus for carbon dioxide according to Claim 11 or Claim 12; supplying a gas to the bag portion or extracting a gas from the bag portion to cause the gas to flow across the microporous film; absorbing carbon dioxide from the gas at relatively low temperature using a carbon dioxide absorbent; and releasing carbon dioxide from the carbon dioxide absorbent and into the gas at a relatively high temperature.

14. The method according to Claim 13, wherein the microporous film further comprises a carbon dioxide absorbent inside pores.

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