Acidic gas adsorbent, structure provided with acidic gas adsorbent, acidic gas adsorption device, acidic gas recovery device, method for producing acidic gas adsorbent, and sheet-like structure

Abstract

The present invention provides a novel acidic gas adsorbent which is suitable for adsorption of an acidic gas. An acidic gas adsorbent 10 according to the present invention is provided with a porous sheet 1 that contains a polymer P. The polymer P has an amino group. The porous sheet 1 has a three-dimensional network skeleton that is configured from the polymer P. A structure 15 according to the present invention is provided with the acidic gas adsorbent 10 and a ventilation path 14. An acidic gas adsorption device 200 according to the present invention is provided with an adsorption unit 221 which has a gas inlet 222 and a gas outlet 223. The acidic gas adsorbent 10 is contained in the adsorption unit 221.

Description

Acidic gas adsorbent, structure with acidic gas adsorbent, acidic gas adsorption device, acidic gas recovery device, method for producing acidic gas adsorbent, and sheet-like structure

[0001] The present invention relates to an acidic gas adsorbent, a structure provided with the acidic gas adsorbent, an acidic gas adsorption device, an acidic gas recovery device, a method for producing an acidic gas adsorbent, and a sheet-like structure.

[0002] In recent years, carbon capture and storage (CCS) and carbon capture and utilization (CCU) have been considered as a way to reduce the amount of carbon dioxide in the atmosphere. In CCS and CCU, carbon dioxide is sometimes captured by separating it from the atmosphere.

[0003] As a method for separating acidic gases such as carbon dioxide from the atmosphere, an adsorption method has been developed in which the acidic gas is adsorbed onto an adsorbent. The adsorbent used in the adsorption method can adsorb the acidic gas by, for example, contacting the atmosphere.

[0004] For example, Patent Document 1 discloses an adsorbent having a substrate coated with an amine compound. Specifically, Patent Document 1 discloses a substrate on which porous alumina particles are supported, and the pores of the porous particles are filled with an amine compound.

[0005] Special Publication No. 2014-533195

[0006] There is a need for new acid gas adsorbents suitable for adsorbing acid gases.

[0007] The present invention provides an acidic gas adsorbent comprising a porous sheet containing a polymer, wherein the polymer has an amino group, and the porous sheet has a three-dimensional network skeleton constituted by the polymer.

[0008] The present invention further provides a structure comprising the above-described acid gas adsorbent and a ventilation path.

[0009] The present invention further provides an acidic gas adsorption device comprising an adsorption section having a gas inlet and a gas outlet, the adsorption section containing the above-mentioned acidic gas adsorbent.

[0010] Furthermore, the present invention provides an acidic gas recovery apparatus comprising the above-mentioned acidic gas adsorbent and a medium path, wherein a heat medium for heating the acidic gas adsorbent passes through the medium path during a desorption operation in which the acidic gas adsorbed by the acidic gas adsorbent is desorbed from the acidic gas adsorbent.

[0011] The present invention further provides a method for producing an acidic gas adsorbent having a porous sheet, comprising: a step (I) of curing a mixed liquid containing a compound group including an amine monomer and a porogen to obtain a cured body; and a step (II) of removing the porogen from the sheet-like cured body to obtain the porous sheet.

[0012] The present invention further provides a sheet-like structure comprising: a porous sheet containing a polymer; and a support supporting the porous sheet, wherein the polymer has an amino group; and the porous sheet has a three-dimensional network skeleton composed of the polymer.

[0013] According to the present invention, a new acidic gas adsorbent suitable for adsorbing acidic gases can be provided.

[0014] 1 is a cross-sectional view schematically showing an acidic gas adsorbent according to one embodiment of the present invention. FIG. 2 is a view for explaining a manufacturing method of an acidic gas adsorbent. FIG. 3 is a view for explaining a manufacturing method of an acidic gas adsorbent. FIG. 4 is a view for explaining a method for measuring the amount of carbon dioxide adsorption by an acidic gas adsorbent. FIG. 5 is a cross-sectional view schematically showing a modified example of an acidic gas adsorbent. FIG. 6 is a perspective view schematically showing an example of a structure provided with an acidic gas adsorbent. FIG. 7 is a perspective view schematically showing a modified example of a structure provided with an acidic gas adsorbent. FIG. 8 is a perspective view schematically showing another modified example of a structure provided with an acidic gas adsorbent. FIG. 9 is a perspective view schematically showing an example of an acidic gas recovery apparatus. FIG. 10 is a cross-sectional view showing the general configuration of a modified example of an acidic gas recovery apparatus. FIG. 11 is a scanning electron microscope (SEM) image of a cross section of a porous sheet produced in Example 1. FIG. 12 is a graph showing the results of measuring the amount of carbon dioxide adsorption for the acidic gas adsorbents of Example 1 and Comparative Examples 1 to 3. FIG. 13 is a graph showing the results of measuring the amount of carbon dioxide adsorption for the acidic gas adsorbents of Example 2 and Comparative Examples 4 to 6.

[0015] An acidic gas adsorbent according to a first aspect of the present invention comprises a porous sheet containing a polymer, the polymer having an amino group, and the porous sheet having a three-dimensional network skeleton composed of the polymer.

[0016] In a second aspect of the present invention, for example, in the acidic gas adsorbent according to the first aspect, the porous sheet includes continuous pores that are formed three-dimensionally and continuously.

[0017] In a third aspect of the present invention, for example, in the acidic gas adsorbent according to the first or second aspect, the porous sheet contains the polymer as a main component.

[0018] In a fourth aspect of the present invention, for example, in the acidic gas adsorbent according to any one of the first to third aspects, the amino group includes a secondary amino group.

[0019] In a fifth aspect of the present invention, for example, in the acidic gas adsorbent according to any one of the first to fourth aspects, the polymer is an epoxy polymer containing constitutional units derived from amine monomers.

[0020] In a sixth aspect of the present invention, for example, in the acidic gas adsorbent according to any one of the first to fifth aspects, the glass transition temperature of the polymer is 40° C. or lower.

[0021] In a seventh aspect of the present invention, for example, in the acidic gas adsorbent according to any one of the first to sixth aspects, the specific surface area of ​​the porous sheet is 1.0 m 2 / g or more.

[0022] In an eighth aspect of the present invention, for example, in the acidic gas adsorbent according to any one of the first to seventh aspects, the porosity of the porous sheet is 20% or more.

[0023] In a ninth aspect of the present invention, for example, the acidic gas adsorbent according to any one of the first to eighth aspects further comprises a support for supporting the porous sheet.

[0024] In a tenth aspect of the present invention, for example, the acidic gas adsorbent according to any one of the first to ninth aspects has an adsorption amount of carbon dioxide of 0.1 mmol / cm when contacted with a mixed gas composed of carbon dioxide, nitrogen, and water vapor for 15 hours. 3 Here, the concentration of the carbon dioxide in the mixed gas is 400 vol ppm, and the mixed gas has a temperature of 20° C. and a humidity of 50% RH.

[0025] In an eleventh aspect of the present invention, for example, the acidic gas adsorbent according to any one of the first to tenth aspects has a flat plate shape or a corrugated shape.

[0026] A structure according to a twelfth aspect of the present invention comprises: an acidic gas adsorbent according to any one of the first to eleventh aspects; and a ventilation path.

[0027] An acidic gas adsorption device according to a thirteenth aspect of the present invention comprises an adsorption section having a gas inlet and a gas outlet, and the adsorption section accommodates the acidic gas adsorbent according to any one of the first to eleventh aspects.

[0028] An acidic gas recovery apparatus according to a fourteenth aspect of the present invention comprises an acidic gas adsorbent according to any one of the first to eleventh aspects; and a medium path, wherein a heat medium for heating the acidic gas adsorbent passes through the medium path during a desorption operation in which the acidic gas adsorbed by the acidic gas adsorbent is desorbed from the acidic gas adsorbent.

[0029] In a fifteenth aspect of the present invention, for example, in the acidic gas recovery apparatus according to the fourteenth aspect, the medium path penetrates the acidic gas adsorbent in a thickness direction of the acidic gas adsorbent.

[0030] In a sixteenth aspect of the present invention, for example, the acidic gas recovery apparatus according to the fourteenth aspect includes two of the acidic gas adsorbents, and the medium path is formed between the two acidic gas adsorbents.

[0031] In a seventeenth aspect of the present invention, for example, in an acidic gas recovery apparatus according to any one of the fourteenth to sixteenth aspects, after the desorption operation, a cooling medium for cooling the acidic gas adsorbent passes through the medium path.

[0032] A method for producing an acidic gas adsorbent according to an eighteenth aspect of the present invention is a method for producing an acidic gas adsorbent provided with a porous sheet, comprising: a step (I) of curing a mixed solution containing a compound group including an amine monomer and a porogen to obtain a cured body; and a step (II) of removing the porogen from the sheet-like cured body to obtain the porous sheet.

[0033] In a nineteenth aspect of the present invention, for example, in the step (I) of the production method according to the eighteenth aspect, the mixed liquid is applied onto a support, and the resulting coating film is cured to obtain the sheet-like cured body.

[0034] A sheet-like structure according to a twentieth aspect of the present invention comprises: a porous sheet containing a polymer; and a support supporting the porous sheet, wherein the polymer has an amino group; and the porous sheet has a three-dimensional network skeleton composed of the polymer.

[0035] An acidic gas adsorbent according to a twenty-first aspect of the present invention comprises a porous resin sheet containing a polymer, wherein the polymer has an amino group.

[0036] A sheet-like structure according to a twenty-second aspect of the present invention comprises: a porous resin sheet containing a polymer; and a support supporting the porous resin sheet, wherein the polymer has an amino group.

[0037] The present invention will be described in detail below, but the following description is not intended to limit the present invention to a specific embodiment.

[0038] <Embodiment of Acidic Gas Adsorbent> As shown in Fig. 1 , an acidic gas adsorbent 10 of this embodiment includes a porous sheet 1 containing a polymer P, and further includes, for example, a support 2. The porous sheet 1 is a porous resin sheet containing a polymer P. The polymer P has amino groups and has the function of adsorbing acidic gases due to the amino groups.

[0039] The porous sheet 1 has a three-dimensional network skeleton composed of polymer P. Specifically, the porous sheet 1 has a porous structure, and the porous structure contains pores derived from the three-dimensional network skeleton. The pores derived from the three-dimensional network skeleton have a size that can be observed, for example, when observed at a magnification of 5000 times using a scanning electron microscope (SEM). The diameter (average pore diameter) of these pores is preferably 0.1 μm or more and 5 μm or less, more preferably 3 μm or less. When the pore diameter is 0.1 μm or more, gas diffusivity within the porous sheet 1 tends to be sufficiently ensured. When the pore diameter is 5 μm or less, even with a moderate porosity, the three-dimensional network skeleton in the porous sheet 1 does not become too thick, making it easy to suppress a decrease in the diffusion rate of acidic gases into the polymer P.

[0040] In another aspect, the present invention provides an acidic gas adsorbent (10) comprising a porous sheet (1) having a porous structure including pores derived from a three-dimensional mesh skeleton, wherein the three-dimensional mesh skeleton contains a polymer (P) having an amino group.

[0041] The support 2 supports the porous sheet 1 and is in direct contact with the porous sheet 1. The acidic gas adsorbent 10 equipped with the support 2 is suitable for use as a component of an acidic gas recovery device, which will be described later. The acidic gas adsorbent 10 may or may not further include a fixing means for fixing the porous sheet 1 and the support 2 together. A specific example of the fixing means is an adhesive, more specifically, an adhesive sheet containing an adhesive. In this specification, the term "adhesive" is used to encompass a pressure-sensitive adhesive.

[0042] The acidic gas adsorbent 10 may not include the support 2 and may be composed of only the porous sheet 1. That is, the acidic gas adsorbent 10 may be a free-standing film (single-layer film) of the porous sheet 1.

[0043] The acidic gas adsorbent 10 is typically a sheet-like structure. The acidic gas adsorbent 10 as a sheet-like structure has, for example, a flat plate shape or a corrugated shape.

[0044] In another aspect, the present invention provides a sheet-like structure comprising: a porous sheet 1 containing a polymer P; and a support 2 supporting the porous sheet 1, wherein the polymer P has an amino group; and the porous sheet 1 has a three-dimensional network skeleton composed of the polymer P.

[0045] Furthermore, from another aspect, the present invention provides a sheet-like structure comprising: a porous sheet 1 having a porous structure including pores derived from a three-dimensional mesh skeleton; and a support 2 supporting the porous sheet 1, wherein the three-dimensional mesh skeleton contains a polymer P having an amino group.

[0046] (Porous Sheet) In the porous sheet 1, the polymer P contains, for example, at least one amino group selected from the group consisting of a primary amino group, a secondary amino group, and a tertiary amino group. From the viewpoint of acidic gas adsorption, the polymer P preferably contains at least one selected from the group consisting of a primary amino group and a secondary amino group, and particularly preferably contains a secondary amino group. In other words, the amino group possessed by the polymer P preferably contains a secondary amino group. The polymer P having a secondary amino group also tends to easily desorb the adsorbed acidic gas. In other words, the polymer P having a secondary amino group allows the regeneration treatment of the acidic gas adsorbent 10 under relatively mild conditions. The polymer P may contain a tertiary amino group, but it does not have to contain a tertiary amino group.

[0047] The weight ratio of nitrogen elements in polymer P is, for example, 5 wt % or more, preferably 10 wt % or more. The higher this weight ratio, the more likely it is that the acidic gas adsorption ability of acidic gas adsorbent 10 will improve. The upper limit of the weight ratio of nitrogen elements in polymer P is not particularly limited, and is, for example, 30 wt %. Note that when all of the nitrogen elements contained in polymer P are derived from amino groups, the weight ratio of nitrogen elements described above can be regarded as the weight ratio of amino groups in polymer P.

[0048] The density of the amino groups in the polymer P is, for example, 1 mmol / g or more, preferably 5 mmol / g or more, and more preferably 10 mmol / g or more. The upper limit of the density of the amino groups is not particularly limited and is, for example, 30 mmol / g. In this specification, the density of the amino groups in the polymer P means the amount of amino groups contained in 1 g of the polymer P.

[0049] The polymer P may contain functional groups other than amino groups, such as hydroxyl groups, ether groups, ester groups, and amide groups.

[0050] The polymer P is, for example, an epoxy polymer containing a structural unit U1 derived from an amine monomer. This epoxy polymer is, for example, at least one selected from the group consisting of a polymer P1 of a monomer group containing an amine monomer and an epoxy monomer, and a reaction product P2 of a compound group containing an amine monomer and an epoxy prepolymer, and is preferably the polymer P1. A specific example of the reaction product P2 is an epoxy prepolymer crosslinked by an amine monomer (crosslinked product).

[0051] As described above, the monomers for forming the polymer P1 include amine monomers and epoxy monomers, and preferably consist only of these monomers. That is, the polymer P1 is preferably a polymer of amine monomers and epoxy monomers.

[0052] The amine monomer is a monomer containing at least one amino group, for example, at least one primary amino group. The number of primary amino groups contained in the amine monomer is preferably 2 or more, may be 3 or more, or may be 4 or more. The upper limit of the number of primary amino groups is not particularly limited, and may be, for example, 30 or 10. The amine monomer may contain a secondary amino group or a tertiary amino group in addition to the primary amino group, but may not contain a tertiary amino group. The molecular weight of the amine monomer is not particularly limited, and is, for example, less than 5,000, preferably 3,000 or less, and may be 1,000 or less, or 500 or less.

[0053] Examples of the amine monomers include ethylamine, ethylenediamine, 1,4-butylenediamine, 1,5-pentanediamine, 1,6-hexanediamine, 1,7-heptanediamine, 1,8-octanediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, iminobispropylamine, bis(hexamethylene)triamine, 1,3,6-trisaminomethylhexane, tris(2-aminoethyl)amine, and N,N'-bis(3-aminopropyl)ethylene. Examples of suitable amine monomers include aliphatic amines such as diamine, polymethylenediamine, trimethylhexamethylenediamine, polyetherdiamine, and polyethyleneimine; and alicyclic amines such as isophoronediamine, menthanediamine, piperazine, N-aminoethylpiperazine, 3,9-bis(3-aminopropyl)2,4,8,10-tetraoxaspiro(5,5)undecane adduct, bis(4-amino-3-methylcyclohexyl)methane, bis(4-aminocyclohexyl)methane, and modified products thereof. In some cases, the amine monomer may be an aliphatic polyamidoamine containing a polyamine and a dimer acid. The amine monomer is preferably an aliphatic amine, particularly triethylenetetramine (TETA). The amine monomers may be used alone or in combination of two or more.

[0054] The epoxy monomer is a monomer containing at least one epoxy group. The number of epoxy groups contained in the epoxy monomer is preferably 2 or more, and may be 3 or more, or 4 or more. The upper limit of the number of epoxy groups contained in the epoxy monomer is not particularly limited, and is, for example, 10. The molecular weight of the epoxy monomer is not particularly limited, and is, for example, less than 1,000, and preferably 500 or less.

[0055] Examples of epoxy monomers include monofunctional epoxy compounds such as n-butyl glycidyl ether, higher alcohol glycidyl ether, allyl glycidyl ether, 2-ethylhexyl glycidyl ether, phenyl glycidyl ether, cresyl glycidyl ether, p-sec-butylphenyl glycidyl ether, and t-butylphenyl glycidyl ether; diepoxy alkanes such as 1,5-hexadiene diepoxide, 1,7-octadiene diepoxide, and 1,9-decadiene diepoxide; (poly)ethylene glycol diglycidyl ether; Examples of suitable epoxy monomers include ether group-containing polyfunctional epoxy compounds such as ethylene glycol diglycidyl ether (EDE), (poly)propylene glycol diglycidyl ether, 1,4-butanediol diglycidyl ether, neopentyl glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, trimethylolpropane polyglycidyl ether, and pentaerythritol polyglycidyl ether; and amino group-containing polyfunctional epoxy compounds such as N,N,N',N'-tetraglycidyl metaxylenediamine and 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane. The epoxy monomer is preferably an ether group-containing polyfunctional epoxy compound such as ethylene glycol diglycidyl ether (EDE) or pentaerythritol tetraglycidyl ether (PETG). The epoxy monomers can be used alone or in combination of two or more. When using a monofunctional epoxy compound, it is preferable to use it in combination with another epoxy monomer containing two or more epoxy groups. The monofunctional epoxy compound can also be used as a reactive diluent to adjust the viscosity of the monomers used to form polymer P1.

[0056] Amine monomers for forming reactant P2 include those described above for polymer P1.

[0057] The epoxy prepolymer contains, for example, at least one epoxy group. The number of epoxy groups contained in the epoxy prepolymer is preferably 2 or more, and may be 3 or more, or 4 or more. The upper limit of the number of epoxy groups contained in the epoxy prepolymer is not particularly limited and is, for example, 100. The weight-average molecular weight of the epoxy prepolymer is not particularly limited and is, for example, 1,000 to 50,000.

[0058] Examples of epoxy prepolymers include aromatic epoxy resins and non-aromatic epoxy resins. Examples of aromatic epoxy resins include polyphenyl-based epoxy resins, epoxy resins containing a fluorene ring, epoxy resins containing triglycidyl isocyanurate, and epoxy resins containing a heteroaromatic ring (e.g., a triazine ring). Examples of polyphenyl-based epoxy resins include bisphenol A-type epoxy resins, brominated bisphenol A-type epoxy resins, bisphenol F-type epoxy resins, bisphenol AD-type epoxy resins, stilbene-type epoxy resins, biphenyl-type epoxy resins, bisphenol A novolac-type epoxy resins, cresol novolac-type epoxy resins, diaminodiphenylmethane-type epoxy resins, and tetrakis(hydroxyphenyl)ethane-based epoxy resins. Examples of non-aromatic epoxy resins include aliphatic glycidyl ether-type epoxy resins, aliphatic glycidyl ester-type epoxy resins, alicyclic glycidyl ether-type epoxy resins, alicyclic glycidyl amine-type epoxy resins, and alicyclic glycidyl ester-type epoxy resins. The epoxy prepolymers can be used alone or in combination of two or more.

[0059] As described above, polymer P as an epoxy polymer contains a structural unit U1 derived from an amine monomer. When polymer P is polymer P1, polymer P further contains a structural unit U2 derived from an epoxy monomer. The content of structural unit U1 in polymer P, particularly polymer P1, is, for example, 30 wt % or more, and preferably 50 wt % or more. There are no particular limitations on the upper limit of the content of structural unit U1, and it is, for example, 80 wt %. The content of structural unit U2 in polymer P, particularly polymer P1, is, for example, 20 wt % to 70 wt %.

[0060] When preparing polymer P, the compounding ratio of the amine monomer to the epoxy monomer or epoxy prepolymer is preferably set so that the ratio of the equivalent of the epoxy group contained in the epoxy monomer or epoxy prepolymer to the equivalent of the active hydrogen of the primary amino group contained in the amine monomer is, for example, 1 or less, preferably 0.9 or less, and more preferably 0.5 or less.

[0061] The glass transition temperature Tg of the polymer P is not particularly limited, and is, for example, 40°C or lower, preferably 30°C or lower, more preferably 20°C or lower, and even more preferably 15°C or lower. When the glass transition temperature Tg of the polymer P is low to this extent, the acidic gas adsorbent 10 can be regenerated under relatively mild conditions, for example, by heat treatment at a low temperature. The lower limit of the glass transition temperature Tg of the polymer P is, from the viewpoint of ensuring sufficient acidic gas adsorption ability in the acidic gas adsorbent 10 and from the viewpoint of heat resistance, for example, -100°C, preferably -50°C, and more preferably -10°C. In this specification, the glass transition temperature Tg is the midpoint glass transition temperature (T mg ) The polymer P generally corresponds to a thermosetting resin. The polymer P is solid at, for example, 25°C, preferably in the range of 25°C to 80°C.

[0062] The weight average molecular weight of the polymer P is not particularly limited and is, for example, 500 or more, preferably 1000 or more, more preferably 10000 or more, and even more preferably 100000 or more. The upper limit of the weight average molecular weight of the polymer P is, for example, 10,000,000.

[0063] The porous sheet 1 contains, for example, polymer P as a main component. In this specification, "main component" means the component that is contained in the porous sheet 1 in the largest amount by weight. The content of polymer P in the porous sheet 1 is, for example, 50 wt% or more, preferably 70 wt% or more, more preferably 90 wt% or more, and may be 95 wt% or more, or may be 99 wt% or more. The porous sheet 1 may be composed essentially of polymer P only. The higher the content of polymer P, the more the acid gas adsorption ability of the acid gas adsorbent 10 tends to improve.

[0064] The porous sheet 1 may be substantially composed of only the polymer P, or may further contain other materials other than the polymer P. Examples of such other materials include reaction accelerators, plasticizers, fillers, pigments, dyes, antioxidants, conductive materials, antistatic agents, UV absorbers, flame retardants, and antioxidants. It is preferable that the porous sheet 1 does not contain, for example, other materials such as porous particles such as alumina or a binder for binding the porous particles together.

[0065] The reaction accelerator is used, for example, when synthesizing the polymer P. Examples of the reaction accelerator include tertiary amines such as triethylamine and tributylamine; and imidazoles such as 2-phenol-4-methylimidazole, 2-ethyl-4-methylimidazole, and 2-phenol-4,5-dihydroxyimidazole. These reaction accelerators can accelerate the reaction for synthesizing the polymer P1, for example.

[0066] Examples of fillers include fibers and fiber structures containing fibers. Examples of fibers include glass fibers; natural fibers such as wood pulp, cotton, and hemp (e.g., Manila hemp); and chemical fibers (synthetic fibers) such as polyester fibers, rayon, vinylon, acetate fibers, polyvinyl alcohol (PVA) fibers, polyamide fibers, polyolefin fibers, and polyurethane fibers. Examples of fiber structures include woven fabrics, nonwoven fabrics, and paper. A specific example of a fiber structure is glass paper. When the porous sheet 1 contains a fiber structure as a filler, dimensional changes of the porous sheet 1 tend to be suppressed during use of the acidic gas adsorbent 10.

[0067] When the porous sheet 1 contains a fibrous structure as a filler, the three-dimensional network skeleton containing the polymer P and the fibrous structure may exist independently in the porous sheet 1. In this case, the porous structure of the porous sheet 1 has, for example, pores derived from the three-dimensional network skeleton containing the polymer P as well as pores derived from the fibrous structure. In this case, the porous sheet 1 can be considered to have a composite of the three-dimensional network skeleton containing the polymer P and the fibrous structure.

[0068] The fibrous structure as the filler preferably has a high tensile strength from the viewpoint of suppressing dimensional changes in the porous sheet 1. As an example, the fibrous structure has a tensile strength S TD Preferably, the tensile strength (S) is 1 MPa or more. Test 1: A fiber structure is cut into a size of 10 mm wide x 100 mm long to prepare a test piece. At this time, the longitudinal direction of the test piece is aligned with the TD (transverse direction) of the fiber structure. The test piece is set in a tensile tester, and a tensile test is carried out under the conditions of a chuck distance of 20 mm and a tensile speed of 100 mm / min. The tensile strength (S) when the test piece is elongated by 3% is TD Identify.

[0069] In the above tensile test, the test force applied to the test piece (the test force when the test piece is elongated by 3%, unit: N / 10 mm) is measured when the distance between the chucks increases by 0.6 mm after the start of the test. Based on the obtained test force value (N / 10 mm) and the thickness (μm) of the fiber structure, the tensile strength S TD The tensile test is carried out in an atmosphere of 25°C. TD (MPa) = test force (N / 10 mm) / (thickness (μm) / 100)

[0070] Tensile strength S of the fiber structure TD is more preferably 2 MPa or more, and may be 3 MPa or more, 4 MPa or more, 5 MPa or more, 6 MPa or more, 7 MPa or more, or even 8 MPa or more. TD The upper limit is not particularly limited and is, for example, 30 MPa.

[0071] Furthermore, the fibrous structure had a tensile strength S measured by the same method as in Test 1 above, except that the longitudinal direction of the test specimen was aligned with the MD (machine direction) of the fibrous structure. MD The tensile strength S is preferably 1 MPa or more. MD is more preferably 2 MPa or more, and may be 5 MPa or more, 8 MPa or more, 10 MPa or more, 11 MPa or more, or even 12 MPa or more. MD The upper limit is not particularly limited and is, for example, 30 MPa.

[0072] The density d of nitrogen elements in the porous sheet 1 is not particularly limited, and is, for example, 1 mmol / g or more, preferably 5 mmol / g or more, and more preferably 10 mmol / g or more. The upper limit of the density d of nitrogen elements is not particularly limited, and is, for example, 30 mmol / g. Note that, when all the nitrogen elements contained in the porous sheet 1 are derived from amino groups, the density d of nitrogen elements can be regarded as the density of the amino groups in the porous sheet 1.

[0073] The density d of the nitrogen element can be measured by the following method. First, the weight ratio w (wt%) of the nitrogen element contained in the porous sheet 1 is measured using a commercially available CHN elemental analyzer. Based on the obtained results, the density d of the nitrogen element can be calculated using the following formula: Density d (mmol / g) = (weight ratio w (wt%) × 1000) / (atomic weight of nitrogen × 100)

[0074] The amount of amino groups per unit volume of the porous sheet 1 is, for example, 4.0 mmol / cm 3 or more, and 3 Above, 4.5 mmol / cm 3 or more, 5.0 mmol / cm 3 or more, 6.0 mmol / cm 3 or more, 7.0 mmol / cm 3 or more, and further 8.0 mmol / cm 3 The upper limit of the amount of amino groups is not particularly limited, and may be, for example, 20 mmol / cm 3 is.

[0075] The weight ratio of nitrogen elements in the porous sheet 1 is, for example, 5 wt % or more, preferably 10 wt % or more. The higher this weight ratio, the more the acidic gas adsorption ability of the acidic gas adsorbent 10 tends to improve. The upper limit of the weight ratio of nitrogen elements in the porous sheet 1 is not particularly limited, and is, for example, 30 wt %. Note that when all of the nitrogen elements contained in the porous sheet 1 are derived from amino groups, the weight ratio of the nitrogen elements can be regarded as the weight ratio of amino groups in the porous sheet 1.

[0076] As described above, the porous sheet 1 has a three-dimensional network skeleton composed of polymer P. The three-dimensional network skeleton may, for example, contain polymer P as a main component and substantially contain only polymer P. The three-dimensional network skeleton may further contain components other than polymer P. In the porous sheet 1, for example, the above-mentioned three-dimensional network skeleton extends continuously. The pores contained in the porous sheet 1 are, for example, continuous pores formed in a three-dimensional continuous manner. In other words, the porous sheet 1 includes, for example, continuous pores formed in a three-dimensional continuous manner. The porous sheet 1 may have closed pores or may have through-holes penetrating the porous sheet 1. Note that the porous sheet 1 preferably does not contain, for example, fibers containing polymer P, and is preferably not a nonwoven fabric containing such fibers. That is, in this embodiment, the porous sheet 1 does not include, for example, a nonwoven fabric having fibers containing polymer P.

[0077] The thickness of the porous sheet 1 is not particularly limited and is, for example, 1000 μm or less, preferably 500 μm or less, and more preferably 300 μm or less. As will be described later, the smaller the thickness of the porous sheet 1, the larger the cross-sectional area of ​​the ventilation path of, for example, a structure, particularly a honeycomb structure, produced using the acidic gas adsorbent 10 can be adjusted. A structure with a large cross-sectional area of ​​the ventilation path is suitable for reducing pressure loss that occurs when contacting an acidic gas. In this embodiment, the porous sheet 1 tends to have a relatively large amount of amino group substance per unit volume. This porous sheet 1 tends to be able to sufficiently adsorb acidic gases even when the thickness of the sheet 1 is small. The lower limit of the thickness of the porous sheet 1 is not particularly limited and is, for example, 10 μm.

[0078] The specific surface area of ​​the porous sheet 1 is not particularly limited, and is, for example, 0.1 m 2 / g or more, preferably 1.0m 2 / g or more, more preferably 2.0m 2 The upper limit of the specific surface area of ​​the porous sheet 1 is not particularly limited, and is, for example, 10 m 2 / g. The specific surface area of ​​the porous sheet 1 means the BET (Brunauer-Emmett-Teller) specific surface area determined by nitrogen gas adsorption. The BET specific surface area can be measured by a method conforming to the provisions of JIS Z8830:2013.

[0079] The porosity of the porous sheet 1 is, for example, 20% or more, preferably 30% or more, and more preferably 40% or more. The upper limit of the porosity of the porous sheet 1 is not particularly limited, and may be, for example, 80% or 60%. The porosity of the porous sheet 1 is determined by the volume V (cm 3 ), weight W (g) and true density D (g / cm 3 The true density D means the specific gravity of the material that constitutes the porous sheet 1. Porosity (%) = 100 × (V - (W / D)) / V

[0080] It is preferable that the porous sheet 1 is suppressed from undergoing dimensional change during use of the acidic gas adsorbent 10, particularly when the acidic gas adsorbent 10 comes into contact with water. A porous sheet 1 with suppressed dimensional change tends to be less likely to fall off the support 2 or an acidic gas recovery device during use of the acidic gas adsorbent 10. Furthermore, this porous sheet 1 is less likely to deform during use of the acidic gas adsorbent 10, and is less likely to experience gas passage obstruction due to deformation. As described above, a porous sheet 1 containing a fibrous structure as a filler tends to be suppressed from undergoing dimensional change during use of the acidic gas adsorbent 10.

[0081] As an example, the porous sheet 1 has a dimensional change rate R TDis preferably 5% or less. Test 2: A test piece is prepared by cutting the porous sheet 1 into a size of 30 mm length x 20 mm width. At this time, the length direction of the test piece is aligned with the MD direction of the porous sheet 1 (if a fiber structure is included, the MD direction of the fiber structure), and the width direction of the test piece is aligned with the TD direction of the porous sheet 1 (if a fiber structure is included, the TD direction of the fiber structure). The test piece is dried for 2 hours in a vacuum atmosphere at 60°C. The test piece is placed in a dry room with a dew point of approximately -60°C. The dimensions of the test piece are measured in the dry room, and the obtained values ​​are considered to be the dimensions of the test piece in a dry state. Next, an immersion test is performed in which the test piece is immersed in pure water at 22°C for 2 hours. The dimensions of the test piece after the immersion test are measured, and the obtained values ​​are considered to be the dimensions of the test piece in a water-absorbed state. The width L of the test piece in a dry state TD1 (mm), and the horizontal length L of the test piece in the water-absorbed state TD2 (mm) to the dimensional change rate R TD Calculate the percentage.

[0082] The dimensional change rate R TD The dimensional change rate R (%) can be calculated by the following formula: TD = 100 × | L TD2 -L TD1 | / L TD1

[0083] Dimensional change rate R of porous sheet 1 TD is more preferably 4% or less, and may be 3% or less, 2% or less, 1% or less, or even 0.5% or less. TD The lower limit of is not particularly limited, and is, for example, 0.01%.

[0084] Furthermore, the porous sheet 1 has a dimensional change rate R MD The dimensional change rate R is preferably 5% or less. MD is the longitudinal length L of the test piece in a dry state MD1 (mm), and the longitudinal length L of the test piece in a water-absorbed state MD2 The dimensional change rate R can be calculated based on the thickness (mm) using the following formula: MD = 100 × | L MD2 -L MD1 | / L MD1

[0085] Dimensional change rate R of porous sheet 1 MD is more preferably 4% or less, and may be 3% or less, 2% or less, or even 1% or less. MD The lower limit of is not particularly limited, and is, for example, 0.01%.

[0086] (Support) The material of the support 2 is not particularly limited, and examples thereof include ceramics such as cordierite, alumina, cordierite-α alumina, silicon nitride, zircon mullite, spodumene, alumina-silica magnesia, zircon silicate ester, sillimanite, magnesium silicate, zircon, petalite, and aluminosilicate; metals such as aluminum, titanium, copper, stainless steel, Fe—Cr alloy, and Cr—Al—Fe alloy; silicone resin, polyolefin, polyester, polyurethane, polycarbonate, and polyether ether ketone; Examples of the material include polyphenylene oxide, polyethersulfone, melamine, polyamide, poly(meth)acrylate, polystyrene, poly(meth)acrylonitrile, polyimide, polyfurfural alcohol, phenol furfuryl alcohol, melamine formaldehyde, resorcinol formaldehyde, cresol formaldehyde, phenol formaldehyde, polyvinyl alcohol dialdehyde, polycyanurate, poly(meth)acrylamide, epoxy resin, agar, agarose, cellulose, and other resins. The material of the support 2 preferably has excellent thermal conductivity and durability, and is resistant to deterioration due to rusting or hydrolysis when it comes into contact with water.

[0087] The support 2 may or may not have a porous structure. Examples of the support 2 having a porous structure include paper, nonwoven fabric, foam, and mesh. Examples of the support 2 not having a porous structure include a non-porous sheet and foil. From the viewpoint of easily producing the acidic gas adsorbent 10 having a corrugated shape, the support 2 is preferably an aluminum sheet, paper, nonwoven fabric, or the like.

[0088] The support 2 may function as a planar heater, and may be a planar thermoelectric heater or a Peltier element.

[0089] The thickness of the support 2 is not particularly limited and is, for example, 1 μm to 100 μm. The support 2 may be thinner than the porous sheet 1.

[0090] (Method for manufacturing acidic gas adsorbent) A method for manufacturing acidic gas adsorbent 10 includes, for example, step (I) of curing a mixed liquid L containing a group of compounds including an amine monomer and a porogen to obtain a cured body B, and step (II) of removing the porogen from the sheet-like cured body B to obtain a porous sheet 1.

[0091] In step (I), the compound group is typically a monomer group containing an amine monomer and an epoxy monomer, although the compound group may contain an epoxy prepolymer instead of or in addition to the epoxy monomer.

[0092] A porogen is a solvent that can dissolve, for example, the monomers and prepolymers contained in the compound group and can also induce reaction-induced phase separation after the compound group has reacted. Specific examples of porogens include cellosolves such as methyl cellosolve and ethyl cellosolve, esters such as ethylene glycol monomethyl ether acetate and propylene glycol monomethyl ether acetate, glycols such as polyethylene glycol, polypropylene glycol, and polyoxyalkylene glycol, and ethers such as polyoxyethylene monomethyl ether and polyoxyethylene dimethyl ether. Specific examples of polyoxyalkylene glycols include poly(1,2-butanediol)-6 propylene glycol and polyoxypropylene diglyceryl ether. The porogen may be a polar solvent such as ethyl acetate, N,N-dimethylformamide (DMF), acetonitrile, ethanol, or isopropanol, a nonpolar solvent such as toluene, or a mixture thereof. Porogens can be used alone or in combination of two or more.

[0093] Components other than the compounds and the porogen may be further added to the mixed solution L. Examples of the other components include the above-mentioned reaction accelerators.

[0094] In step (I), the compounds react to form a polymer P. This cures the mixed liquid L, yielding a cured product B. The reaction of the compounds is typically a polymerization reaction of an amine monomer and an epoxy monomer. However, the reaction of the compounds may also be a crosslinking reaction of an epoxy prepolymer with an amine monomer. In the reaction of the compounds, the amino group of the amine monomer reacts with the epoxy group of the epoxy monomer or the epoxy prepolymer. The reaction of the compounds can be carried out by adding energy to the mixed liquid L. The energy added to the mixed liquid L is preferably thermal energy. As an example, the reaction of the compounds can be promoted by heating the mixed liquid L at a temperature of 40°C to 100°C. However, the energy added to the mixed liquid L may also be light energy.

[0095] The cured product B contains a polymer P and a porogen. In the cured product B, the polymer P and the porogen undergo phase separation to form a co-continuous structure. The cured product B obtained in step (I) is typically in the form of a sheet. The sheet-like cured product B can be produced, for example, by applying the mixed liquid L onto a support 2 (typically a support 2 having no porous structure) and curing the resulting coating film. The method for applying the mixed liquid L is not particularly limited, and methods such as roll coating, spin coating, and dip coating can be used.

[0096] The sheet-like cured body B can also be produced by bringing the mixed liquid L into contact with a sheet-like substrate other than the support 2 described above, and then curing the mixed liquid L. As the substrate, for example, a release liner or a fiber structure can be used. The substrate may be a laminate containing a release liner and a fiber structure. When a fiber structure is used as the substrate, the mixed liquid L tends to penetrate into the fiber structure when brought into contact with the fiber structure. By curing the mixed liquid L in a state in which the mixed liquid L has penetrated into the fiber structure, a cured body containing the fiber structure as a filler can be obtained.

[0097] The shape of the cured body B obtained in step (I) does not have to be sheet-like, and may be, for example, block-like, particularly cylindrical or columnar. A block-like cured body B can be produced, for example, by curing the mixed liquid L filled in a mold in step (I). In this case, the sheet-like cured body B used in step (II) can be obtained by cutting the vicinity of the surface of the block-like cured body B to a predetermined thickness. For example, when the cured body B is cylindrical or columnar, a sheet-like cured body B can be produced by cutting the vicinity of the surface of the cured body B while rotating the cured body B around the cylindrical or columnar axis.

[0098] In step (II), the method for removing the porogen from the sheet-like cured body B is not particularly limited. For example, the porogen may be extracted and removed from the cured body B by immersing the cured body B in a solvent. Examples of solvents that can be used for extracting the porogen include water, aliphatic hydrocarbon solvents, aromatic hydrocarbon solvents, aliphatic alcohol solvents, ether solvents, halogen-containing organic solvents, and ester solvents. Examples of aliphatic hydrocarbon solvents include n-hexane, cyclohexane, methylcyclohexane, n-heptane, n-octane, isooctane, petroleum ether, and benzine. Examples of aromatic hydrocarbon solvents include toluene, xylene, mesitylene, and benzene. Examples of aliphatic alcohol solvents include methanol, ethanol, isopropanol, butanol, cyclohexanol, ethylene glycol, propylene glycol, propylene glycol monomethyl ether, and diethylene glycol. Examples of ether solvents include diethyl ether, diisopropyl ether, dibutyl ether, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, propylene glycol dimethyl ether, propylene glycol diethyl ether, diethylene glycol dimethyl ether, tetrahydrofuran, dioxane, and anisole. Examples of halogen-containing organic solvents include dichloromethane, chloroform, carbon tetrachloride, dichloroethane, and chlorobenzene. Examples of ester solvents include ethyl acetate. These solvents can be used alone or in combination of two or more.

[0099] In step (II), by removing the porogen from the sheet-like cured body B, for example, a porous sheet 1 having a flat plate shape can be obtained. As an example, when the cured body B is produced by applying the mixed liquid L onto the support 2, by removing the porogen from the cured body B, a sheet-like acidic gas adsorbent 10 including the porous sheet 1 and the support 2 can be obtained. Note that a free-standing film of the porous sheet 1 may be produced by a method using a substrate other than the support 2, and the free-standing film may be used as the acidic gas adsorbent 10. A free-standing film of the porous sheet 1 may be produced, and the free-standing film may be fixed to the support 2 using a fixing means such as an adhesive sheet, and the resulting film may be used as the acidic gas adsorbent 10.

[0100] The acidic gas adsorbent 10 produced by the above method usually has a flat plate shape. The acidic gas adsorbent 10 having a flat plate shape may further be subjected to a corrugating process. This allows the acidic gas adsorbent 10 to have a corrugated shape.

[0101] As an example, the acidic gas adsorbent 10 can be manufactured using a manufacturing apparatus 100 shown in FIG. 2A. FIG. 2A shows a schematic configuration of the manufacturing apparatus 100. The manufacturing apparatus 100 includes a feed roll 45 that feeds the support 2, a take-up roll 49 that takes up the manufactured acidic gas adsorbent 10, and a plurality of guide rolls 46, 47, and 48 located between the feed roll 45 and the take-up roll 49. In the manufacturing apparatus 100, the support 2 is transported from the feed roll 45 to the take-up roll 49. The manufacturing apparatus 100 further includes a mixed liquid discharge section 20, a first heating section 30, an extraction section 40, and a second heating section 35, which are arranged in this order in the transport direction of the support 2. Note that in the manufacturing apparatus 100, a substrate other than the support 2 may be used instead of the support 2.

[0102] The mixed liquid discharge unit 20 includes a first supply unit 21, a second supply unit 22, a mixing unit 23, and a discharge port 24. The first supply unit 21 can send a first raw material 5 to the mixing unit 23. The second supply unit 22 can send a second raw material 6 to the mixing unit 23. As an example, the first raw material 5 contains an amine monomer, and the second raw material 6 contains an epoxy monomer and / or an epoxy prepolymer. At least one selected from the group consisting of the first raw material 5 and the second raw material 6 contains a porogen. In the mixing unit 23, the first raw material 5 and the second raw material 6 are mixed to prepare a mixed liquid L.

[0103] The mixed liquid L prepared in the mixing unit 23 is discharged to the outside of the mixed liquid discharge unit 20 through the discharge port 24. For example, the mixed liquid discharge unit 20 is located near the guide roll 46, and can apply the mixed liquid L onto the support 2 transported from the payout roll 45 to the guide roll 46. This allows a coating film 7 to be formed on the support 2. The coating film 7, together with the support 2, passes through the guide roll 47 and is sent to the first heating unit 30.

[0104] The first heating section 30 is equipped with a heater 31 for heating the coating film 7. The coating film 7 is heated by moving through the first heating section 30. This causes the coating film 7 to harden, forming a sheet-like hardened body 8. The hardened body 8 is sent to the extraction section 40 together with the support 2.

[0105] The extraction unit 40 contains a solvent 41 for extracting the porogen from the cured body 8. In the extraction unit 40, the cured body 8 is immersed in the solvent 41. This removes the porogen from the cured body 8, and a porous sheet 1 is formed. The porous sheet 1 is sent to the second heating unit 35 together with the support 2.

[0106] The second heating section 35 is equipped with a heater 36 for drying the porous sheet 1 sent from the extraction section 40. The porous sheet 1 is heated by moving through the second heating section 35. This dries the porous sheet 1, and a sheet-like acidic gas adsorbent 10 comprising the porous sheet 1 and the support 2 is obtained. This acidic gas adsorbent 10 passes through a guide roll 48 and is taken up by a take-up roll 49.

[0107] The manufacturing apparatus 100 for the acidic gas adsorbent 10 is not limited to that shown in FIG. 2A. FIG. 2B shows a schematic configuration of a manufacturing apparatus 110 according to a modified example. As shown in FIG. 2B, the manufacturing apparatus 110 does not include the extraction section 40 and the second heating section 35. Except for the above, the configuration of the manufacturing apparatus 110 is the same as that of the manufacturing apparatus 100. Therefore, elements common to these manufacturing apparatuses 100 and 110 are given the same reference numerals, and their description may be omitted. The following descriptions of each embodiment may be mutually applicable unless technically inconsistent. Furthermore, each embodiment may be mutually combined unless technically inconsistent.

[0108] In the manufacturing apparatus 110, the hardened body 8 formed in the first heating section 30 passes through a guide roll 48 together with the support 2 and is wound up by a winding roll 49. This produces a roll of the hardened body 8 and the support 2. The roll is immersed in a solvent to extract the porogen from the hardened body 8, thereby producing a sheet-like acidic gas adsorbent 10.

[0109] (Amount of Carbon Dioxide Adsorbed by Acidic Gas Adsorbent) The acidic gas adsorbent 10 of this embodiment tends to have high adsorption ability for acidic gases such as carbon dioxide. As an example, when the acidic gas adsorbent 10 is brought into contact with a mixed gas G composed of carbon dioxide, nitrogen, and water vapor for 15 hours, the amount of carbon dioxide adsorbed a is, for example, 0.1 mmol / cm 3 or more, preferably 0.3 mmol / cm 3 More preferably, 0.5 mmol / cm 3 More preferably, it is 0.7 mmol / cm 3 More preferably, 0.8 mmol / cm 3 or more, and particularly preferably 1.0 mmol / cm 3 The upper limit of the amount a of carbon dioxide adsorption is not particularly limited, and may be, for example, 10 mmol / cm 3 is.

[0110] [Method for measuring the amount of adsorption of carbon dioxide] A method for measuring the amount of adsorption a of carbon dioxide will be described below. The amount of adsorption a can be measured using, for example, a measuring device 200 shown in FIG. 3. The measuring device 200 includes a first tank 230 and a second tank 231. As an example, the first tank 230 stores dry nitrogen, and the second tank 231 stores a mixed gas of dry nitrogen and dry carbon dioxide. The concentration of carbon dioxide in the mixed gas in the second tank 231 is, for example, 5 vol %.

[0111] The measuring device 200 further includes a first container 240 containing water 270, and a first path 260 for sending nitrogen from the first tank 230 to the first container 240. The first path 260 has one end connected to a gas outlet of the first tank 230 and the other end disposed in the water 270 of the first container 240. The nitrogen sent from the first tank 230 to the first container 240 is humidified by contact with the water 270. A mass flow controller 235 is disposed in the first path 260 for adjusting the flow rate of nitrogen sent from the first tank 230 to the first container 240.

[0112] The measuring apparatus 200 further includes a second container 241, a second path 262, and a bypass path 261. The second path 262 connects the first container 240 and the second container 241. The humidified nitrogen sent to the first container 240 is sent to the second container 241 via the second path 262. The bypass path 261 branches off from the first path 260 at a position between the first tank 230 and the mass flow controller 235 and connects to the second path 262. A portion of the nitrogen sent from the first tank 230 flows into the bypass path 261 and is sent to the second container 241 via the second path 262. A mass flow controller 236 is disposed in the bypass path 261 to adjust the flow rate of nitrogen sent from the first tank 230 to the bypass path 261.

[0113] The measuring device 200 further includes a third path 263 for sending the mixed gas from the second tank 231 to the second path 262. The third path 263 has one end connected to the gas outlet of the second tank 231 and the other end connected to the second path 262. A mass flow controller 237 is disposed in the third path 263 for adjusting the flow rate of the mixed gas sent from the second tank 231 to the second path 262. The mixed gas sent to the second path 262 is sent to the second container 241 through the second path 262.

[0114] The measuring device 200 further includes a third container 242 and a fourth path 264. The third container 242 contains water 271 and an adsorption unit 221 disposed in the water 271. In the third container 242, the temperature of the water 271 is maintained at 20°C. The adsorption unit 221 has a gas inlet 222 and a gas outlet 223. The adsorption unit 221 contains an acidic gas adsorbent 10 therein. The adsorption unit 221 is configured to prevent the water 271 from penetrating into the interior. The adsorption unit 221 is typically a tube made of a hydrophobic resin, for example, a fluororesin such as tetrafluoroethylene-perfluoroalkoxyethylene copolymer (PFA). As an example, the tube serving as the adsorption unit 221 has an inner diameter of 4 mm and an outer diameter of 6 mm. The adsorption unit 221 is configured to be detachable from the measuring device 200.

[0115] The measuring device 200 can also be used as an acidic gas adsorption device equipped with an adsorption section 221. In another aspect, the present invention provides an acidic gas adsorption device 200 equipped with an adsorption section 221 having a gas inlet 222 and a gas outlet 223, the adsorption section 221 accommodating an acidic gas adsorbent 10. The adsorption section 221 of the acidic gas adsorption device 200 may accommodate a structure, described below, equipped with the acidic gas adsorbent 10.

[0116] The fourth path 264 connects the second container 241 and the third container 242. More specifically, the fourth path 264 is connected to the gas inlet 222 of the adsorption unit 221 in the third container 242. A first concentration meter 250 is disposed in the fourth path 264 to measure the concentration of carbon dioxide in the gas supplied to the adsorption unit 221. As the first concentration meter 250, for example, a CO2 / H2O gas analyzer LI-850-3 manufactured by LI-COR Corporation can be used.

[0117] The measuring device 200 further includes a fifth path 265 connected to the gas outlet 223 of the adsorption unit 221 for discharging gas from the adsorption unit 221 to the outside of the measuring device 200. A back pressure valve 255 and a second concentration meter 251 are disposed in the fifth path 265. The back pressure valve 255 can adjust the pressure inside the adsorption unit 221 to a constant value. The second concentration meter 251 can measure the concentration of carbon dioxide in the gas discharged from the adsorption unit 221. For example, an LI-850-3 CO2 / H2O gas analyzer manufactured by LI-COR can be used as the second concentration meter 251.

[0118] Each path of the measuring device 200 is made up of, for example, a metal or resin pipe.

[0119] [Pretreatment] In the method for measuring the adsorption amount a, first, the acidic gas adsorbent 10 is dried. The drying treatment is performed, for example, by treating the acidic gas adsorbent 10 for two hours or more under conditions of 60°C in a vacuum atmosphere. Next, the dried acidic gas adsorbent 10 is packed into the adsorption section 221 in a dry room with a dew point of approximately -60°C. At this time, the acidic gas adsorbent 10 is measured in advance to specify the volume of the acidic gas adsorbent 10. The weight of the acidic gas adsorbent 10 packed into the adsorption section 221 is, for example, 50 mg. Next, a fourth path 264 and a fifth path 265 are connected to both ends of the adsorption section 221, and the adsorption section 221 is immersed in water 271 in the third container 242.

[0120] Next, nitrogen from the first tank 230 and the mixed gas from the second tank 231 are supplied to the second container 241 via the first path 260, the second path 262, the bypass path 261, and the third path 263 of the measuring device 200. These gases are mixed in the second container 241 to obtain a mixed gas G composed of carbon dioxide, nitrogen, and water vapor. In the second container 241, the carbon dioxide concentration in the mixed gas G is adjusted to 400 vol ppm. The mixed gas G has a temperature of 20°C and a humidity of 50% RH. The mixed gas G is supplied to the adsorption section 221 via the fourth path 264 at a flow rate sufficient for the weight of the acidic gas adsorbent 10, for example, a flow rate of 300 mL / min for 50 mg of acidic gas adsorbent 10. In the adsorption section 221, the pressure of the mixed gas G is adjusted to 107 kPa by the back pressure valve 255.

[0121] Next, while the mixed gas G is being supplied to the adsorption section 221, the adsorption section 221 is removed from the third container 242 and immersed in a water bath (not shown) at 80°C for two hours or more. The adsorption section 221 is immersed in the water bath until the carbon dioxide concentration measured by the first concentration meter 250 and the carbon dioxide concentration measured by the second concentration meter 251 become substantially the same value. This completes the pretreatment of the acidic gas adsorbent 10 in the adsorption section 221.

[0122] [Adsorption Test] Next, while the mixed gas G is being supplied to the adsorption section 221, the adsorption section 221 is removed from the hot water bath and immersed in the water 271 in the third container 242. This starts the adsorption test for the acidic gas adsorbent 10 in the adsorption section 221. The adsorption test is carried out for 15 hours after the start. When the adsorption test is carried out for 15 hours, it can usually be considered that the adsorption of carbon dioxide by the acidic gas adsorbent 10 has reached equilibrium.

[0123] In the adsorption test, the amount of carbon dioxide adsorbed by the acidic gas adsorbent 10 for 15 hours from the start is measured. The amount of carbon dioxide adsorbed by the acidic gas adsorbent 10, M, can be calculated from the results of measuring the difference between the carbon dioxide concentration measured by the first concentration meter 250 and the carbon dioxide concentration measured by the second concentration meter 251 over time. Based on the amount of carbon dioxide, M, the amount of carbon dioxide adsorbed by the acidic gas adsorbent 10 per 1 cm 3The amount of carbon dioxide adsorbed by the acidic gas adsorbent 10 in 15 hours is calculated, and the calculated value is specified as the adsorption amount a.

[0124] As described above, in conventional adsorbents, for example, an amine compound is filled into the pores of porous particles supported on a substrate. Such adsorbents require porous particles and a binder to bind the porous particles together, making it difficult to significantly adjust the amount of amino groups per unit volume of the adsorbent. In conventional adsorbents, increasing the amount of amine compound filled to increase the amount of amino groups per unit volume can clog the pores of the porous particles, resulting in a decrease in the adsorption performance for acidic gases. In contrast, the acidic gas adsorbent 10 of the present embodiment utilizes a porous sheet 1 having a three-dimensional network skeleton composed of polymer P, which allows the amount of amino groups per unit volume to be easily increased while maintaining the pores of the porous sheet 1. The acidic gas adsorbent 10 of the present embodiment tends to have high adsorption performance for acidic gases and can be said to be suitable for adsorbing acidic gases.

[0125] (Uses of Acidic Gas Adsorbent) The acidic gas adsorbent 10 of this embodiment can adsorb acidic gases. Examples of acidic gases include carbon dioxide, hydrogen sulfide, carbonyl sulfide, sulfur oxides (SOx), hydrogen cyanide, and nitrogen oxides (NOx), and carbon dioxide is preferred.

[0126] The acidic gas adsorbent 10 can be used, for example, by the following method. First, a mixed gas containing an acidic gas is brought into contact with the acidic gas adsorbent 10. The mixed gas contains, for example, other gases in addition to the acidic gas. Examples of other gases include non-polar gases such as hydrogen and nitrogen, and inert gases such as helium, with nitrogen being preferred. The mixed gas is typically atmospheric air. The mixed gas may also be off-gas from a chemical plant or thermal power plant.

[0127] The temperature of the mixed gas is, for example, room temperature (23°C). The concentration of the acidic gas in the mixed gas is not particularly limited and, under standard conditions (0°C, 101 kPa), is, for example, 0.01 vol% (100 volppm) or more, preferably 0.04 vol% (400 volppm) or more, and may be 1.0 vol% or more. The upper limit of the carbon dioxide concentration in the mixed gas is not particularly limited and, under standard conditions, is, for example, 10 vol%. The pressure of the mixed gas is typically equal to atmospheric pressure in the environment in which the acidic gas adsorbent 10 is used. However, the mixed gas to be contacted with the acidic gas adsorbent 10 may be pressurized.

[0128] The acidic gas adsorbent 10 that has come into contact with the mixed gas adsorbs the acidic gas contained in the mixed gas. The operation of bringing the mixed gas into contact with the acidic gas adsorbent 10 is continued, for example, until the adsorption of the acidic gas by the acidic gas adsorbent 10 reaches equilibrium.

[0129] Next, the acidic gas adsorbent 10 that has adsorbed the acidic gas is regenerated. The regeneration can be performed, for example, by heating the acidic gas adsorbent 10. The heating temperature of the acidic gas adsorbent 10 is, for example, 50 to 80°C. The acidic gas adsorbent 10 may be heated under a reduced pressure or a vacuum. By heating the acidic gas adsorbent 10, the acidic gas is desorbed from the acidic gas adsorbent 10. This regenerates the acidic gas adsorbent 10, allowing it to be reused. The acidic gases, particularly carbon dioxide, desorbed from the acidic gas adsorbent 10 can be used as raw materials for chemical synthesis or as dry ice. The adsorption of acidic gases by the acidic gas adsorbent 10 and the regeneration of the acidic gas adsorbent 10 can be performed using the measuring device 200 (acidic gas adsorption device) described above or the acidic gas recovery device described below.

[0130] <Modifications of Acidic Gas Adsorbent> The acidic gas adsorbent 10 may include a plurality of porous sheets 1. The acidic gas adsorbent 11 shown in Fig. 4 includes two porous sheets 1A and 1B. Except for this, the structure of the acidic gas adsorbent 11 is the same as the structure of the acidic gas adsorbent 10.

[0131] In the acidic gas adsorbent 11, the support 2 is located between the two porous sheets 1A and 1B and is in direct contact with each of the porous sheets 1A and 1B. The composition and structure of the porous sheet 1A may be the same as or different from those of the porous sheet 1B.

[0132] <Embodiment of Structure> As shown in Fig. 5A , a structure 15 of this embodiment includes the above-described acidic gas adsorbent 10 and a ventilation path 14. Note that the acidic gas adsorbent 11 shown in Fig. 4 can also be used instead of the acidic gas adsorbent 10. The structure 15 is typically a honeycomb structure having a plurality of ventilation paths 14 extending in the same direction.

[0133] In the structure 15, the acidic gas adsorbent 10 preferably includes a support 2 together with a porous sheet 1. In this acidic gas adsorbent 10, the porous sheet 1 may contain a fibrous structure as a filler. However, the acidic gas adsorbent 10 included in the structure 15 may be a free-standing film of the porous sheet 1.

[0134] The structure 15 includes an adsorbent unit U in which, for example, a corrugated acidic gas adsorbent 10A and a flat acidic gas adsorbent 10B are stacked. In the acidic gas adsorbent 10A, a plurality of peaks 12 and a plurality of valleys 13 are alternately arranged. A ventilation path 14 is formed between the peaks 12 or valleys 13 of the acidic gas adsorbent 10A and the acidic gas adsorbent 10B. In this embodiment, the direction x is the direction (wave direction) in which the plurality of peaks 12 and the plurality of valleys 13 of the acidic gas adsorbent 10A are alternately arranged. The direction y is the stacking direction of the acidic gas adsorbents 10A and 10B in the adsorbent unit U. The direction z is perpendicular to the directions x and y, and is the direction in which the ventilation path 14 extends.

[0135] The structure 15 includes, for example, a plurality of adsorbent units U. The number of adsorbent units U in the structure 15 is not particularly limited and may be, for example, 2 to 100. In the structure 15, the plurality of adsorbent units U are stacked in the direction y so that a plurality of acidic gas adsorbents 10A and a plurality of acidic gas adsorbents 10B are arranged alternately. By stacking the plurality of adsorbent units U, the structure 15 has a block shape.

[0136] The ventilation path 14 is a through-hole that penetrates the structure 15 in the direction z. The ventilation path 14 is surrounded by the acidic gas adsorbents 10A and 10B. In the structure 15, the acidic gas moves in the direction z through the ventilation path 14 and is efficiently adsorbed by the acidic gas adsorbents 10A and 10B.

[0137] In the structure 15, the smaller the thickness of the porous sheet 1 in the acidic gas adsorbents 10A and 10B, the larger the cross-sectional area of ​​the ventilation path 14 can be adjusted. A structure 15 with a large cross-sectional area of ​​the ventilation path 14 is suitable for reducing pressure loss that occurs when the structure 15 comes into contact with acidic gas. A structure 15 with reduced pressure loss can reduce the power of a fan used to move acidic gas, for example. Note that the acidic gas adsorbent 10 tends to have a relatively large amount of amino group substance per unit volume, and therefore tends to be able to sufficiently adsorb acidic gases even when the thickness of the porous sheet 1 is small.

[0138] <Modifications of the Structure> The shape of the structure 15 including the acidic gas adsorbent 10 is not limited to that shown in Fig. 5A. The structure 16 shown in Fig. 5B has a shape in which one adsorbent unit U is wound around a central tube 50. Except for this, the configuration of the structure 16 is the same as the configuration of the structure 15.

[0139] The structure 16 has a cylindrical shape. In the structure 16, the multiple peaks 12 and the multiple valleys 13 of the acidic gas adsorbent 10A are alternately arranged in the circumferential direction of the structure 16. The ventilation paths 14 formed between the peaks 12 or valleys 13 of the acidic gas adsorbent 10A and the acidic gas adsorbent 10B penetrate the structure 16 in the extension direction of the central tube 50. In the structure 16, the acidic gas moves through the ventilation paths 14 in the extension direction of the central tube 50 and is efficiently adsorbed by the acidic gas adsorbents 10A and 10B.

[0140] <Another Modified Example of the Structure> The structure does not need to include the corrugated acid gas adsorbent 10A, and does not need to be a honeycomb structure like structures 15 and 16. Structure 17 shown in Fig. 5C includes only a flat acid gas adsorbent 10B as the acid gas adsorbent 10. In detail, structure 17 includes a plurality of acid gas adsorbents 10B, which are arranged with gaps between them. The gap between two acid gas adsorbents 10B functions as an air passage 14.

[0141] The structure 17 may further include a fixing member 55 for fixing the plurality of acidic gas adsorbents 10B to ensure the above-mentioned ventilation path 14. The fixing member 55 is, for example, a rod. As an example, a through-hole penetrating the acidic gas adsorbent 10B in the thickness direction is formed in each of the plurality of acidic gas adsorbents 10B, and a rod serving as the fixing member 55 is inserted into the through-hole of each acidic gas adsorbent 10B to fix the plurality of acidic gas adsorbents 10B. The rod serving as the fixing member 55 may be a bolt having a male thread formed on its side. In this case, the ventilation path 14 can be more reliably ensured by threading a nut onto the bolt at a position between two acidic gas adsorbents 10B. In this example, the nut functions as a spacer.

[0142] In the example of Fig. 5C, each of the plurality of acidic gas adsorbents 10B has a rectangular shape in a plan view, and through-holes are formed near the four corners. Furthermore, the acidic gas adsorbent 10C includes four fixing members 55, which are inserted into the four through-holes formed in the four corners of the acidic gas adsorbent 10B. However, the number and positions of the through-holes formed in the acidic gas adsorbent 10B and the number of fixing members 55 are not limited to the example of Fig. 5C.

[0143] In the structure 17, the acid gas is efficiently adsorbed by the two acid gas adsorbents 10B while moving through the ventilation path 14 between the two acid gas adsorbents 10B.

[0144] 6A , an acidic gas recovery apparatus 300 of the present embodiment includes the above-described acidic gas adsorbent 10 and a medium path 60. Note that the acidic gas adsorbent 11 shown in FIG. 4 can also be used instead of the acidic gas adsorbent 10. In the acidic gas recovery apparatus 300, a heat medium 61 that heats the acidic gas adsorbent 10 passes through the medium path 60 during a desorption operation in which the acidic gases adsorbed by the acidic gas adsorbent 10 are desorbed from the acidic gas adsorbent 10.

[0145] In the acidic gas recovery system 300, the acidic gas adsorbent 10 preferably includes a support 2 together with a porous sheet 1. In this acidic gas adsorbent 10, the porous sheet 1 may contain a fibrous structure as a filler. However, the acidic gas adsorbent 10 included in the acidic gas recovery system 300 may also be a free-standing membrane of the porous sheet 1.

[0146] The acidic gas recovery system 300 includes, for example, a plurality of acidic gas adsorbents 10. The plurality of acidic gas adsorbents 10 may be arranged with a gap therebetween, and the gap between two acidic gas adsorbents 10 may function as the ventilation path 14. In the acidic gas recovery system 300, the configurations of the acidic gas adsorbents 10 and the ventilation path 14 may be the same as those described above for the structures 15 to 17.

[0147] In the acidic gas recovery system 300, the medium path 60 is configured, for example, by piping made of a metal such as copper, more specifically, a heat transfer tube. In the acidic gas recovery system 300, the medium path 60 penetrates, for example, the acidic gas adsorbent 10 in the thickness direction of the acidic gas adsorbent 10. More specifically, through holes that penetrate the acidic gas adsorbent 10 in the thickness direction are formed in the acidic gas adsorbent 10, and the medium path 60 is inserted into the through holes of the acidic gas adsorbent 10. The acidic gas recovery system 300 typically has a structure similar to that of a fin-tube heat exchanger that includes heat transfer fins and heat transfer tubes that penetrate the heat transfer fins.

[0148] The medium path 60 may have a U-shape and be inserted into two through-holes formed in the acidic gas adsorbent 10. The number of through-holes formed in the acidic gas adsorbent 10 and the number of medium paths 60 are not limited to those shown in Figure 6A. For example, four or more through-holes may be formed in the acidic gas adsorbent 10, and two or more U-shaped medium paths 60 may be inserted into the through-holes of the acidic gas adsorbent 10.

[0149] As described above, the medium path 60 functions as a path for the heat medium 61 that heats the acidic gas adsorbent 10 during the desorption operation. However, the medium path 60 can also be used as a path for the cooling medium that cools the acidic gas adsorbent 10 after the desorption operation. In other words, the medium path 60 may serve as both a path for the heat medium 61 and a path for the cooling medium.

[0150] The acidic gas recovery apparatus 300 further includes a casing (not shown) that houses the acidic gas adsorbent 10 and the medium path 60. The casing has, for example, a mixed gas inlet for sending a mixed gas containing acidic gas into the interior of the casing. The casing may further include a desorption gas outlet for discharging the desorbed gas desorbed from the acidic gas adsorbent 10 to the outside of the casing during desorption operation, and a purge gas inlet for sending a purge gas into the interior of the casing. Note that in the casing, the mixed gas inlet may also serve as the purge gas inlet. Furthermore, the casing may have a medium inlet for sending a heat medium 61 or a cooling medium to the medium path 60, and a medium outlet for discharging the heat medium 61 or the cooling medium from the medium path 60.

[0151] [Method of Operating the Acidic Gas Recovery Apparatus] The acidic gas recovery apparatus 300 repeatedly performs, for example, an adsorption operation in which the acidic gas is adsorbed onto the acidic gas adsorbent 10, and a desorption operation in which the acidic gas adsorbed by the acidic gas adsorbent 10 is desorbed from the acidic gas adsorbent 10. By performing the adsorption operation and the desorption operation using the acidic gas recovery apparatus 300, acidic gas can be recovered.

[0152] (Adsorption Operation) The adsorption operation of the acidic gas recovery device 300 is performed, for example, as follows. First, a mixed gas containing acidic gas is sent into the casing through the mixed gas inlet. Examples of the mixed gas include those described above. The mixed gas comes into contact with the acidic gas adsorbent 10 while traveling through the ventilation path 14, for example. This causes the acidic gas adsorbent 10 to adsorb the acidic gas contained in the mixed gas. The adsorption operation is performed, for example, until the adsorption of acidic gas by the acidic gas adsorbent 10 reaches equilibrium.

[0153] (Desorption Operation) The desorption operation of the acidic gas recovery apparatus 300 is performed, for example, as follows. First, purge gas is sent into the interior of the casing through the purge gas inlet, and the purge gas is discharged to the outside of the casing through the desorbed gas outlet. This operation allows the mixed gas remaining inside the casing to be discharged to the outside of the casing, and the inside of the casing can be filled with purge gas. As the purge gas, for example, water vapor gas or a gas containing a high concentration of an acidic gas such as carbon dioxide can be used. Note that instead of or in addition to the operation of sending the purge gas into the casing, an operation of depressurizing the inside of the casing may be performed. This depressurization operation can be performed, for example, by a depressurization device connected to the desorbed gas outlet of the casing.

[0154] Next, while the purge gas is being supplied to the inside of the casing, the heat medium 61 is sent to the medium path 60. Hot water, high-temperature gas, etc. can be used as the heat medium 61. Specific examples of gases contained in the high-temperature gas include chlorofluorocarbons, carbon dioxide, air, and water vapor. The heat medium 61 can be prepared, for example, by using waste heat, a heat pump, or self-heat regeneration.

[0155] By sending the heat medium 61 to the medium path 60, heat exchange occurs between the heat medium 61 and the acidic gas adsorbent 10 via the medium path 60, and the acidic gas adsorbent 10 is heated. The heating temperature of the acidic gas adsorbent 10 is, for example, 50 to 80°C. As a result, the acidic gas is desorbed from the acidic gas adsorbent 10. The desorbed gas desorbed from the acidic gas adsorbent 10 is discharged from a desorbed gas outlet together with a purge gas. This allows the acidic gas to be recovered. Note that if the purge gas contains water vapor, the water vapor can be removed by cooling the purge gas discharged from the desorbed gas outlet and condensing the water vapor. Note that it is not necessarily necessary to use the heat medium 61 to heat the acidic gas adsorbent 10. For example, if the support 2 functions as a planar heater, the acidic gas adsorbent 10 may be heated by passing electricity through the support 2.

[0156] The acidic gas recovery system 300 is configured so that the heat transfer medium 61 does not come into direct contact with the desorbed gas during desorption operation. The acidic gas recovery system 300 can efficiently recover acidic gases. The recovered acidic gases, particularly carbon dioxide, can be used as raw materials for chemical synthesis or as dry ice.

[0157] (Preparatory Operation) After the desorption operation, the acidic gas recovery device 300 may perform a preparatory operation for the adsorption operation. The preparatory operation is performed, for example, as follows. First, the supply of purge gas to the inside of the casing is stopped, and the heat medium 61 is discharged from the medium path 60. Next, a cooling medium is sent to the medium path 60. Antifreeze or the like can be used as the cooling medium. Heat exchange occurs between the cooling medium and the acidic gas adsorbent 10 via the medium path 60, and the acidic gas adsorbent 10 is cooled. The acidic gas adsorbent 10 is cooled to, for example, room temperature (25°C). After the acidic gas adsorbent 10 has cooled, the cooling medium is discharged from the medium path 60, thereby completing preparation for the adsorption operation.

[0158] <Modification of Acidic Gas Recovery Apparatus> The acidic gas recovery apparatus is not limited to the one shown in Fig. 6A . For example, in an acidic gas recovery apparatus 310 shown in Fig. 6B , a medium path 60 is formed between two acidic gas adsorbents 10. In detail, in the acidic gas recovery apparatus 310, of the multiple gaps formed between the multiple acidic gas adsorbents 10, some of the gaps function as the medium path 60, and the remaining gaps function as the ventilation path 14. The medium path 60 and the ventilation path 14 are alternately arranged along the arrangement direction of the multiple acidic gas adsorbents 10. The acidic gas recovery apparatus 310 typically has a structure similar to that of a plate heat exchanger in which multiple heat transfer plates are stacked.

[0159] In the acidic gas recovery apparatus 310, the acidic gas adsorbent 10 preferably includes a support 2 along with a porous sheet 1. In the acidic gas recovery apparatus 310, for example, the porous sheet 1 of the acidic gas adsorbent 10 faces the ventilation path 14, and the support 2 faces the medium path 60. In the acidic gas recovery apparatus 310, a spacer 65 is disposed in the ventilation path 14, and a spacer (not shown) is also disposed in the medium path 60. These spacers are configured to secure the ventilation path 14 and the medium path 60, introduce appropriate fluids into each path, and prevent fluids from leaking into other paths. In FIG. 6B , the ventilation path 14 may be connected to the external space of the acidic gas recovery apparatus 310 at both the back and front of the page, thereby allowing the mixed gas to be introduced into the ventilation path 14 from the external space. Furthermore, during desorption operation of the acidic gas recovery apparatus 310, a member may be disposed between the ventilation path 14 and the external space to block the connection therebetween.

[0160] The acidic gas recovery apparatus 310 further includes a restraining member 70 that restrains the plurality of acidic gas adsorbents 10. The restraining member 70 has, for example, a pair of plate members 71a, 71b, a rod 72, and a fixing member 73. The plate members 71a and 71b are aligned in the arrangement direction of the plurality of acidic gas adsorbents 10, and sandwich the plurality of acidic gas adsorbents 10. The plate members 71a and 71b allow pressure to be applied to the plurality of acidic gas adsorbents 10 in the arrangement direction. The plate members 71a and 71b may be formed with the desorbed gas outlet, purge gas inlet, medium inlet, medium outlet, etc., as described above for the acidic gas recovery apparatus 310.

[0161] A through hole is formed in each of the plate members 71a and 71b, and the rod 72 is inserted into the through hole of the plate members 71a and 71b. The rod 72 may be a bolt with a male thread formed on its side. The fixing member 73, for example, fixes one of the plate members 71a and 71b and the rod 72 to each other. The fixing member 73 is typically a nut with a female thread that can be threaded onto the rod 72. The restraining member 70 has a fixing member 73a that fixes the plate member 71a and the rod 72 to each other, and a fixing member 73b that fixes the plate member 71b and the rod 72 to each other.

[0162] In the example of Fig. 6B, two rods 72 are each fixed by a fixing member 73. However, the number of rods 72 and the like are not limited to the example of Fig. 6B.

[0163] The acidic gas recovery system 310 can be operated in the same manner as the operation method described above for the acidic gas recovery system 300. In the acidic gas recovery system 310, a medium path 60 is formed between two acidic gas adsorbents 10. With this configuration, during desorption operation, the heat transfer medium passes through the medium path 60, thereby allowing the entire acidic gas adsorbent 10 to be uniformly heated.

[0164] Furthermore, unlike the acidic gas recovery system 300, the acidic gas recovery system 310 is configured so that the ventilation path 14 does not interfere with the medium path 60. Therefore, in the acidic gas recovery system 310, the pressure loss caused by the mixed gas passing through the ventilation path 14 during adsorption operation tends to be small.

[0165] The acidic gas recovery system 310 makes it easier to remove components such as the acidic gas adsorbent 10 than the acidic gas recovery system 300. Removing the acidic gas adsorbent 10 from the acidic gas recovery system 310 makes it easier to replace the acidic gas adsorbent 10. Furthermore, removing each component of the acidic gas recovery system 310 makes it easier to perform maintenance such as cleaning on each component.

[0166] The present invention will be described in more detail below with reference to examples and comparative examples, but the present invention is not limited thereto.

[0167] Example 1 First, 5.22 g of poly(1,2-butanediol)-6 propylene glycol (NOF Corporation, Uniol (registered trademark) PB-500) and 5.22 g of polyoxypropylene diglyceryl ether (NOF Corporation, Unilube (registered trademark) DGP-700) were added to a 50 mL Labolan screw cap bottle (AS ONE Corporation). 2.55 g of ethylene glycol diglycidyl ether (Nagase ChemteX Corporation, EX-810) and 3.83 g of pentaerythritol tetraglycidyl ether (Showa Denko K.K., Showfree (registered trademark) PETG) were dissolved in the resulting mixture to prepare a mixture of epoxy monomer and porogen.

[0168] Next, 6.57 g of triethylenetetramine (manufactured by Tosoh Corporation) was added to this mixture to prepare a mixture of epoxy monomer, amine monomer, and porogen. In this mixture, the ratio (E / A) of the equivalent weight (E) of epoxy groups contained in the epoxy monomer to the equivalent weight (A) of active hydrogen of primary amino groups contained in the amine monomer was 0.4.

[0169] Next, the mixture was shaken for 2 minutes using a benchtop shaker (Angel Vibrator Digital 60 Hz) set to intensity 5. Next, using an applicator with a gap of 350 μm, the mixture was applied to a 20 μm-thick aluminum sheet. The resulting coating was cured by leaving it in a dryer at 120°C for 30 minutes. This resulted in a sheet-like cured product containing polymer P having amino groups. This cured product was immersed in ethyl acetate at 60°C for 30 minutes, and this operation was repeated twice with liquid changes. This removed the porogen from the cured product, forming a porous sheet. Next, the product was dried in a dryer at 60°C for 30 minutes, and the aluminum sheet was removed to obtain the acidic gas adsorbent (a free-standing porous sheet) of Example 1. In Example 1, the porous sheet had a three-dimensional network structure composed of polymer P.

[0170] In Example 1, the porous sheet had a thickness of 215 μm and a basis weight of 13.03 mg / cm 2 The porosity calculated from the true density of polymer P was 45%. The density of amino groups in polymer P calculated from the monomer blending ratio was 13.87 mmol / g. The amount of amino groups per unit volume of the porous sheet was 8.39 mmol / cm. 3 It was.

[0171] Example 2 First, a mixed solution of epoxy monomer, amine monomer, and porogen was prepared using the same method as in Example 1, except that the blending amounts were changed as shown in Table 1. Next, the mixed solution was shaken for 2 minutes using a tabletop shaker (Angel Vibrator Digital 60 Hz) set to intensity 5. Next, the mixed solution was applied to a 250 μm-thick glass paper (PHN-50GC, manufactured by Oji F-Tex Co., Ltd.) using an applicator with a 500 μm gap. During this application, the mixed solution penetrated into the glass paper. The glass paper soaked with the mixed solution was left in a dryer at 120°C for 30 minutes to harden the mixed solution. This resulted in a sheet-like cured product containing the amino-containing polymer P and glass paper as a filler. This cured product was immersed in ethyl acetate at 60°C for 30 minutes, and this process was repeated twice, with the solution replaced between applications. This removed the porogen from the cured product, forming a porous sheet. Next, the porous sheet was dried in a dryer at 60° C. for 30 minutes to obtain an acidic gas adsorbent (a free-standing porous sheet) containing glass paper as a filler of Example 2. In Example 2, the porous sheet had a three-dimensional network skeleton composed of polymer P.

[0172] In Example 2, the basis weight of the acidic gas adsorbent (porous sheet) was 15.8 mg / cm 2 The basis weight of the acidic gas adsorbent (15.8 mg / cm 2 ) from the basis weight of the glass paper (5.0 mg / cm 2 ) subtracted (10.8 mg / cm 2 ) can be regarded as the basis weight of the three-dimensional network skeleton composed of polymer P. The true density of polymer P (1.1 g / cm 3 The theoretical thickness of the three-dimensional network skeleton was calculated from the thickness of the polymer P and the porosity (45%) of the three-dimensional network skeleton, and was 179 μm. The density of the amino group in the polymer P calculated from the monomer blending ratio was 12.38 mmol / g. The amount of amino group per unit volume of the three-dimensional network skeleton contained in the porous sheet was 7.49 mmol / cm. 3 Furthermore, the amount of amino groups per unit volume of the porous sheet was 5.27 mmol / cm3 It was.

[0173] (Examples 3 to 6) Except for using the fiber structures shown in Table 1 instead of glass paper, acidic gas adsorbents (free-standing porous sheet membranes) of Examples 3 to 6 were obtained in the same manner as in Example 2. In each of Examples 3 to 6, the porous sheet had a three-dimensional network skeleton composed of polymer P.

[0174] (Comparative Example 1) First, a porous body having a pore volume of 1.5 mL / g and a specific surface area of ​​700 m 2 3.00 g of porous silica (SUNSPERA H-52 manufactured by AGC Si-Tech Co., Ltd.) having a pore diameter of 10 nm and a true density of 2.2 g / mL was prepared and soaked overnight in 60 g of methanol (special grade manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) to produce a dispersion. Next, 0.447 g of triethylenetetramine (TETA, manufactured by Sigma-Aldrich Co.) was prepared as the amine monomer, and 0.174 g of ethylene glycol diglycidyl ether (EX-810, manufactured by Nagase ChemteX Corporation) and 0.261 g of pentaerythritol tetraglycidyl ether (manufactured by Showa Denko K.K., Showfree (registered trademark) PETG) were prepared as the epoxy monomer. The ratio (E / A) of the equivalent (E) of the epoxy group contained in the epoxy monomer to the equivalent (A) of the active hydrogen of the primary amino group contained in the amine monomer was 0.4.

[0175] Next, these monomers were added to the dispersion. As a result, the compounds (TETA, EX-810, and PETG) penetrated into the pores of the porous body, and the compounds came into contact with the surface of the pores of the porous body. Next, using a rotary evaporator, the dispersion was heated at a temperature of 60 ° C. under a reduced pressure atmosphere. As a result, the reaction of the compounds progressed and the solvent contained in the dispersion was distilled off. Next, the porous body was dried by heating it at a temperature of 80 ° C. under a vacuum atmosphere. This resulted in an acidic gas adsorbent of Comparative Example 1 in which polymer P was supported on the porous body. The acidic gas adsorbent of Comparative Example 1 did not have the three-dimensional network skeleton described above in the Examples.

[0176] (Comparative Examples 2 to 6) Acidic gas adsorbents of Comparative Examples 2 to 6 were obtained by the same method as Comparative Example 1, except that the blending amounts of the epoxy monomer and the amine monomer were changed as shown in Table 1. The acidic gas adsorbents of Comparative Examples 2 to 6 did not have the three-dimensional network skeleton described above in the Examples.

[0177] [Cross-section observation of porous sheet] The cross section of the porous sheet produced in Example 1 was observed using a scanning electron microscope (SEM). The obtained SEM image is shown in Figure 7. As can be seen from Figure 7, the porous sheet had a three-dimensional network skeleton composed of polymer P.

[0178] [BET Specific Surface Area] The BET specific surface area by nitrogen gas adsorption was measured for the acidic gas adsorbents prepared in Examples 1 and 2 and Comparative Examples 1 to 6. The BET specific surface area was measured using a specific surface area measuring device (trade name "BELSORP-mini", manufactured by Microtrac-Bell) according to the method specified in JIS Z8830:2013.

[0179] [Glass transition temperature Tg] The glass transition temperature Tg of the polymer P contained in the acidic gas adsorbents prepared in the examples and comparative examples was measured by the following method. First, a polymer having the same composition as the polymer P contained in the acidic gas adsorbent was synthesized. Approximately 5 mg of this polymer was placed in a differential scanning calorimeter (DSC2500 manufactured by TA Instruments). Using this device, the temperature was raised from 30 ° C. to 200 ° C. at a heating rate of 10 ° C. / min under a nitrogen atmosphere and held at that temperature for 1 minute. Next, the sample was cooled to -50 ° C. at a heating rate of 10 ° C. / min, held at that temperature for 1 minute, and then heated to 200 ° C. at a heating rate of 10 ° C. / min. In the DSC curve during the second heating, the first baseline before the specific heat change appeared, the second baseline after the specific heat change appeared, and the tangent passing through the point where the slope of the bending portion due to the specific heat change is greatest were identified. The temperature midway between the intersection of the first baseline and the tangent line and the intersection of the second baseline and the tangent line was identified as the glass transition temperature, Tg.

[0180] [True Density] The true density of the polymer P contained in the acidic gas adsorbents prepared in the Examples and Comparative Examples was determined using the following method. First, a mixed solution containing epoxy monomer and amine monomer was prepared in the same blend amounts as the mixed solution used in the Examples and Comparative Examples. Next, a benchtop shaker (Angel Vibrator Digital 60 Hz) was set to intensity 5 and the mixed solution was shaken for 2 minutes. The mixed solution was poured into a PFA dish with an inner diameter of 75 mm and allowed to harden in a dryer at 120°C for 30 minutes. This resulted in a cured product containing polymer P having amino groups. This cured product was immersed in ethyl acetate at 60°C for 30 minutes, this operation being repeated twice with liquid changes to remove any remaining monomer in the cured product. Next, the product was dried in a dryer at 60°C for 30 minutes to obtain a cured product composed of polymer P. The density of this cured product was measured using an electronic densimeter (EW-300SG, manufactured by Alpha Mirage) in accordance with JIS K7112:1999 (Method for measuring density and specific gravity of non-foamed plastics), and the measured value obtained was considered to be the true density of polymer P.

[0181] [Amount of amino groups per unit volume] For the acidic gas adsorbents of Comparative Examples 1 to 6, the amount of amino groups per unit volume was determined by the following method. First, the acidic gas adsorbent was placed in a simultaneous thermal analysis DSC / TGA device (DSC6500, manufactured by TA Instruments). Using this device, the temperature was increased from 30°C to 100°C at a heating rate of 10°C / min under a nitrogen atmosphere and maintained at that temperature for 40 minutes (Operation 1). This removed water from the acidic gas adsorbent. Next, the temperature was increased from 100°C to 800°C at a heating rate of 10°C / min and maintained at that temperature for 5 minutes (Operation 2). This removed polymer P from the acidic gas adsorbent.

[0182] Next, the ratio of the weight (g) of the acidic gas adsorbent after the above-mentioned operation 1 to the weight (g) of the acidic gas adsorbent before being set in the apparatus (weight retention rate W1 (%)) and the ratio of the weight (g) of the acidic gas adsorbent after the above-mentioned operation 2 to the weight (g) of the acidic gas adsorbent before being set in the apparatus (weight retention rate W2 (%)) were determined. Using the weight retention rates W1 and W2, the ratio F of the weight (g) of the polymer P to the weight (g) of the acidic gas adsorbent was calculated by the following formula: Ratio F = 1 - (1 / W1) × W2

[0183] Next, the volume A (mL) of the porous body per 1 g, the weight B (g) of polymer P relative to 1 g of porous body, the density C (g / mL) of the composite particle composed of the porous body and polymer P, and the density D of the amino groups in the composite particle were calculated using the following formulas: Volume A (mL) = Pore volume (mL) of porous body per 1 g + Weight (g) of porous body / True density of porous body (g / mL) Weight B (g) = Ratio F / (1 - Ratio F) × Weight (g) of porous body Density C of composite particle (g / mL) = (Weight (g) of porous body + Weight B (g)) / Volume A (mL) Density of amino groups D (mmol / g) = Ratio F × Density of amino groups in polymer P (mmol / g)

[0184] Furthermore, the amount of substance E of amino groups per unit volume of the acidic gas adsorbent was calculated using the following formula. In the formula, the filling rate of the composite particles was set to a value (0.74) assuming that the composite particles were most densely packed in the acidic gas adsorbent. The amount of substance E (mmol / cm 3 ) = Density C of composite particle (g / mL) × Packing rate of composite particle × Density D of amino group in composite particle (mmol / g)

[0185]

[0186]

[0187] The abbreviations in Table 1 are as follows: EX-810: Ethylene glycol diglycidyl ether (EX-810, manufactured by Nagase ChemteX Corporation) PETG: Pentaerythritol tetraglycidyl ether (SHOWFREE (registered trademark) PETG, manufactured by Showa Denko K.K.) TETA: Triethylenetetramine (Tosoh Corporation) PB-500: Poly(1,2-butanediol)-6 propylene glycol (UNIOL (registered trademark) PB-500, manufactured by NOF Corporation) DGP-700: Polyoxypropylene diglyceryl ether (UNILUBE (registered trademark) DGP-700, manufactured by NOF Corporation) PHN-50GC: Glass paper (pulp-containing nonwoven fabric) (PHN-50GC, manufactured by Oji F-Tex Co., Ltd.) MP-22: Pulp-containing nonwoven fabric (MP-22, manufactured by Nippon Paper Papylia Co., Ltd.) PY120-01: Synthetic fiber nonwoven fabric (manufactured by Awa Paper Co., Ltd., PY120-01) PY120-32: Synthetic fiber nonwoven fabric (manufactured by Awa Paper Co., Ltd., PY120-32) 120H-PB: Pulp-containing nonwoven fabric (manufactured by Nippon Paper Papylia Co., Ltd., 120H-PB base paper)

[0188] [Amount of carbon dioxide adsorption] The amount of carbon dioxide adsorbed was measured by the method described above for the acidic gas adsorbents of Example 1 and Comparative Examples 1 to 3. In Example 1, the area of ​​the main surface was 4.72 cm 2 The acidic gas adsorbent was cut into pieces and used as measurement samples. In Comparative Examples 1 to 3, measurement samples were used whose weights were adjusted to have approximately the same volume as the measurement sample used in Example 1. The weights of the measurement samples in Comparative Examples 1 to 3 were 49 mg, 64 mg, and 76 mg, respectively. For Comparative Examples 1 to 3, the weights of measurement samples having approximately the same volume as the measurement sample used in Example 1 were calculated by the following formula using the density C (g / mL) of the composite particles composed of the porous body and the polymer P and the packing rate of the composite particles. In the formula below, the packing rate of the composite particles was calculated using a value (0.74) assuming that the composite particles were closest packed in the acidic gas adsorbent. Weight (mg) of measurement sample in Comparative Example = Volume (cm) of measurement sample in Example 1 3 ) × density C (g / mL) × packing rate of composite particles

[0189] The measurement results of the amount of carbon dioxide adsorption for Example 1 and Comparative Examples 1 to 3 are shown in Figure 8. Figure 8 is a graph showing the relationship between the time from the start of the adsorption test and the amount of carbon dioxide adsorbed by the acidic gas adsorbent. It was confirmed from Figure 8 that the amount of carbon dioxide adsorbed saturated and stabilized after a predetermined time. As can be seen from Figure 8, the acidic gas adsorbent of Example 1 had a larger amount of carbon dioxide adsorption per unit volume than Comparative Examples 1 to 3, and was therefore suitable for adsorbing acidic gases. The amount of carbon dioxide adsorbed a when the acidic gas adsorbent of Example 1 was contacted with the above-mentioned mixed gas G for 15 hours was 1.45 mmol / cm 3 It was.

[0190] Furthermore, the carbon dioxide adsorption amount was measured by the above-mentioned method for the acidic gas adsorbents of Example 2 and Comparative Examples 4 to 6. At this time, in Example 2, the area of ​​the main surface was 5.76 cm 2 The acidic gas adsorbent was cut into pieces so as to have a volume similar to that of the measurement sample used in Example 2, and the pieces were used as measurement samples. In Comparative Examples 4 to 6, measurement samples were used whose weights were adjusted to have a volume similar to that of the measurement sample used in Example 2. The weights of the measurement samples in Comparative Examples 4 to 6 were 50 mg, 60 mg, and 72 mg, respectively. For Comparative Examples 4 to 6, the weights of the measurement samples having a volume similar to that of the measurement sample used in Example 2 were calculated by the same method as described above for Comparative Examples 1 to 3.

[0191] The measurement results of the amount of carbon dioxide adsorption for Example 2 and Comparative Examples 4 to 6 are shown in Figure 9. Figure 9 is a graph showing the relationship between the time from the start of the adsorption test and the amount of carbon dioxide adsorbed by the acidic gas adsorbent. It was confirmed from Figure 9 that the amount of carbon dioxide adsorbed saturated and stabilized after a predetermined time. As can be seen from Figure 9, the acidic gas adsorbent of Example 2 had a larger amount of carbon dioxide adsorption per unit volume than Comparative Examples 4 to 6, and was therefore suitable for adsorbing acidic gases. The amount of carbon dioxide adsorbed a when the acidic gas adsorbent of Example 2 was contacted with the above-mentioned mixed gas G for 15 hours was 1.27 mmol / cm 3 It was.

[0192] From the above results, it can be seen that the acidic gas adsorbents of Examples 1 and 2, which are equipped with porous sheets having a three-dimensional network skeleton containing polymer P, have a larger carbon dioxide adsorption capacity than the comparative example, and are suitable for adsorbing acidic gases. The other acidic gas adsorbents of Examples 3 to 6 have the same configuration as Example 2, except for the type of fibrous structure used as the filler. Therefore, it is estimated that the acidic gas adsorbents of Examples 3 to 6 have the same adsorption performance for acidic gases such as carbon dioxide as Example 2.

[0193] The acidic gas adsorbents of the examples have a relatively large amount of amino groups per unit volume, making them suitable for adjusting the thickness of the porous sheet to a small value while maintaining their acidic gas adsorption performance. A porous sheet with a small thickness allows the cross-sectional area of ​​the ventilation channels of structures, particularly honeycomb structures, made using the acidic gas adsorbent to be adjusted to a large value. Structures with a large cross-sectional area of ​​the ventilation channels are suitable for reducing pressure loss that occurs when the structure comes into contact with acidic gases. Thus, the acidic gas adsorbents of the examples can be said to be suitable for reducing pressure loss that occurs in structures equipped with the acidic gas adsorbent.

[0194] (Calculation Example 1) Next, it was assumed that an acidic gas adsorbent was produced using a sheet-like structure formed by agglomerating porous alumina particles. Specifically, it was assumed that the polymer P produced in Example 1 was filled into the pores of the porous particles in the sheet-like structure to produce an acidic gas adsorbent. The amount of amino groups per unit volume of this acidic gas adsorbent was calculated using the following method. Note that the following calculation does not take into account additives such as binders that are normally required in conventional acidic gas adsorbents.

[0195] First, the porous particles have a pore volume of 1.25 mL / g and a specific surface area of ​​175 m 2 The ratio F of the weight of the polymer P to the weight of the acidic gas adsorbent (weight of polymer P (g) / (weight of polymer P (g)+weight of porous particles (g))) was assumed to be 0.39.

[0196] The volume A of the porous particles per 1 g was calculated to be 1.51 mL using the following formula: Volume A (mL) = Pore volume of porous particles per 1 g (mL) + Weight of porous particles (g) / True density of porous particles (g / mL) = 1.25 + 1 / 3.8 = 1.51 (mL).

[0197] In the acidic gas adsorbent, the weight B of polymer P per 1 g of porous particles was calculated to be 0.639 g using the following formula: Weight B (g) = Weight ratio F of polymer P / (1 - Weight ratio F of polymer P) x Weight of porous particles (g) = 0.39 / (1 - 0.39) x 1 = 0.639 (g).

[0198] The density C of the composite particles composed of the porous particles and the polymer P was calculated to be 1.08 g / mL using the following formula: Density C of composite particles (g / mL) = (weight of porous particles (g) + weight B of polymer P (g)) / volume A of porous particles per 1 g (mL) = (1 + 0.639) / 1.51 = 1.08 (g / mL).

[0199] The density D of the amino groups in the composite particles was calculated to be 5.4 mmol / g using the following formula: Density D of amino groups (mmol / g) = Weight ratio F of polymer P × Density of amino groups in polymer P (mmol / g) = 0.39 × 13.87 = 5.4 (mmol / g)

[0200] In Calculation Example 1, the amount of amino groups per unit volume of the acidic gas adsorbent, E, is calculated as 4.34 mmol / cm according to the following formula: 3 In the following formula, the filling rate of the composite particles was calculated as 0.74, assuming that the composite particles were most densely packed in the acidic gas adsorbent. 3 ) = density of composite particle C (g / mL) × filling rate of composite particle × density of amino group in composite particle D (mmol / g) = 1.08 × 0.74 × 5.4 = 4.34 (mmol / cm 3 )

[0201] From the amount of substance E of the amino group, the amount of carbon dioxide that can be adsorbed by the acidic gas adsorbent of Calculation Example 1 is 0.75 mmol / cm at most. 3From this result, it can be seen that the acidic gas adsorbents of Examples 1 and 2 have higher adsorption performance for acidic gases such as carbon dioxide than the acidic gas adsorbent of Calculation Example 1.

[0202] [Tensile Strength of Fiber Structure] The tensile strength S of the fiber structures used in Examples 2 to 6 was measured by the above-mentioned method. TD and S MD The tensile strength S was measured. An autograph device (AGS-50NX, manufactured by Shimadzu Corporation) was used as the tensile tester. TD and S MD Also shown is the test force when the test piece is elongated by 3%.

[0203] [Dimensional Change Rate] The dimensional change rate R TD and R MD was measured.

[0204]

[0205] As can be seen from Table 3, the dimensional change rate of the porous sheet tended to be lower as the tensile strength of the fiber structure used as a filler increased. TD In Examples 2 to 5, the dimensional change rate R of the porous sheet is 2 MPa or more. TD was a sufficiently low value. From the above results, it is presumed that the porous sheets of Examples 2 to 6, particularly Examples 2 to 5, are unlikely to fall off from the support or the acidic gas recovery device during use. Furthermore, it is presumed that these porous sheets are unlikely to deform during use, and that gas passage is unlikely to be hindered due to deformation.

[0206] The acidic gas adsorbent of this embodiment can adsorb, for example, carbon dioxide in the atmosphere.

Claims

1. A porous sheet including a polymer, The polymer has an amino group, The porous sheet has a three-dimensional network structure composed of the polymer, The acidic gas adsorbent, wherein the polymer has a glass transition temperature of 40° C. or lower.

2. A porous sheet including a polymer, The polymer has an amino group, The porous sheet has a three-dimensional network structure composed of the polymer, An acidic gas adsorbent which adsorbs 0.1 mmol / cm 3 or more of carbon dioxide when contacted with a mixed gas composed of carbon dioxide, nitrogen and water vapor for 15 hours. Here, the concentration of the carbon dioxide in the mixed gas is 400 vol ppm, and the mixed gas has a temperature of 20° C. and a humidity of 50% RH.

3. The acidic gas adsorbent according to claim 1 or 2, wherein the porous sheet includes continuous pores that are continuously formed in a three-dimensional shape.

4. The acidic gas adsorbent according to claim 1 or 2, wherein the porous sheet contains the polymer as a main component.

5. The acid gas adsorbent according to claim 1 or 2, wherein the amino group comprises a secondary amino group.

6. 3. The acidic gas adsorbent according to claim 1, wherein the polymer is an epoxy polymer containing structural units derived from amine monomers.

7. The specific surface area of ​​the porous sheet is 1.0 m 2 The acidic gas adsorbent according to claim 1 or 2, wherein the acidic gas adsorbent has a molecular weight of 1 / g or more.

8. 3. The acidic gas adsorbent according to claim 1, wherein the porous sheet has a porosity of 20% or more.

9. The acidic gas adsorbent according to claim 1 or 2, further comprising a support for supporting the porous sheet.

10. 3. The acidic gas adsorbent according to claim 1 or 2, which has a flat plate shape or a corrugated shape.

11. The acidic gas adsorbent according to claim 1 or 2, A ventilation path; A structure comprising:

12. An adsorption section having a gas inlet and a gas outlet, An acidic gas adsorption device, wherein the adsorption section contains the acidic gas adsorbent according to claim 1 or 2.

13. The acidic gas adsorbent according to claim 1 or 2, A media path; Equipped with an acid gas recovery apparatus, wherein during a desorption operation in which the acid gas adsorbed by the acid gas adsorbent is desorbed from the acid gas adsorbent, a heat medium for heating the acid gas adsorbent passes through the medium path.

14. The acid gas recovery apparatus according to claim 13 , wherein the medium path penetrates the acid gas adsorbent in a thickness direction of the acid gas adsorbent.

15. Two of the acid gas adsorbents are provided, The acid gas recovery apparatus of claim 13 , wherein the media path is formed between two of the acid gas adsorbents.

16. The acid gas recovery apparatus according to claim 13 , wherein after the desorption operation, a cooling medium for cooling the acid gas adsorbent passes through the medium path.

17. A method for producing an acidic gas adsorbent according to claim 1 or 2, comprising the steps of: A step (I) of curing a mixed liquid containing a compound group including an amine monomer and a porogen to obtain a cured body; (II) removing the porogen from the sheet-like cured body to obtain the porous sheet; A method for producing an acid gas adsorbent, comprising:

18. The method according to claim 17 , wherein in the step (I), the mixed liquid is applied onto a support, and the resulting coating film is cured to obtain the cured body in a sheet form.