Device for recovering carbon dioxide

Abstract

To provide a device for efficiently recovering carbon dioxides.SOLUTION: A processed gas is introduced to a first gas absorption material to absorb carbon dioxides. Then, heat is added to the first gas absorption material to discharge the carbon dioxides, and the processed gas is introduced to a second gas absorption material to absorb the carbon dioxides. Then, heat is added to the second gas absorption material to discharge the carbon dioxides, and the processed gas is introduced to the first gas absorption material to absorb the carbon dioxides.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a gas absorption material capable of reversibly absorbing acid gas and the like, a gas absorber, and an acid gas absorption device, an acid gas recovery device, a water vapor absorption device, a water vapor recovery device, a heat exchanger, and a heat recovery device using the gas absorber.

Background Art

[0002] In recent years, global warming caused by carbon dioxide and water vapor and environmental pollution caused by hydrogen sulfide and the like discharged from large-scale facilities such as thermal power plants, steel mills, and cement factories have become problems. In order to suppress such climate change and environmental pollution and realize a low-carbon society, research has been underway on a method (CCS; Carbon dioxide Capture and Storage) of separating and recovering acid gases such as carbon dioxide and hydrogen sulfide and water vapor discharged from these large-scale facilities and confining them underground or under the seabed. However, with the current technology, the energy cost for CCS is extremely high, and a significant reduction in energy cost is required. In particular, since the carbon dioxide separation and recovery process accounts for about 60% of the energy cost in CCS, in order to reduce the energy cost in CCS, it is essential to improve the efficiency and significantly reduce the energy consumption of the carbon dioxide separation and recovery process. Also, in the field of energy supply, processes for separating and recovering acid gases such as carbon dioxide and hydrogen sulfide and water vapor from fuel gases such as natural gas with a high carbon dioxide concentration, coal gas generated by integrated gasification combined cycle power generation (IGCC), and hydrogen used in fuel cells are being carried out. Improving the efficiency and energy saving of the separation and recovery process of carbon dioxide and the like is also important for reducing the energy cost in these fields.

[0003] As a method for separating carbon dioxide from exhaust gas, a chemical absorption method using an aqueous amine solution is known. The chemical absorption method is a method in which, in an absorption tower, a low-temperature absorbent (aqueous amine solution) is brought into contact with exhaust gas to selectively absorb carbon dioxide into the absorbent, and then the absorbent is transported to a stripping tower and heated to strip carbon dioxide. This chemical absorption method is actually applied to the treatment of exhaust gas from large-scale facilities. However, there is a problem that it is necessary to heat the absorbent to 130°C or higher to strip carbon dioxide, and the required amount of energy is large. On the other hand, Patent Document 1 and Non-Patent Documents 1 and 2 propose using a temperature-responsive electrolyte whose basicity changes around the phase transition temperature for the separation and recovery of carbon dioxide. Patent Document 1 describes an example in which carbon dioxide is absorbed by a temperature-responsive electrolyte under the condition of 30°C and then stripped from the temperature-responsive electrolyte by heating to 75°C.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Non-Patent Documents

[0005]

Non-Patent Document 1

Non-Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0006] As described above, the temperature-responsive electrolytes described in Patent Document 1 and Non-Patent Documents 1 and 2 were able to absorb carbon dioxide at 30°C and release the absorbed carbon dioxide at 75°C. Therefore, compared with the conventional chemical absorption method, the heating temperature during carbon dioxide recovery can be significantly reduced. However, when the present inventors examined this temperature-responsive electrolyte, it was found that the reversible absorption amount of acidic gas per unit volume was small, and the absorption and release rates of acidic gas were also small, making it insufficient for use in treating exhaust gases from large-scale facilities and various fuel gases.

[0007] Therefore, in order to solve the problems of such conventional technologies, the present inventors aimed to provide a gas absorption material and a gas absorber that can realize a gas absorber with a large reversible absorption amount of gas per unit volume, capable of absorbing and releasing gas at high speeds, and with the heat required for gas release being kept small. Further, by using such a gas absorber, an acidic gas absorption device and an acidic gas recovery device capable of efficiently absorbing and / or recovering acidic gas were provided, and further, a water vapor absorption device, a water vapor recovery device, a heat exchanger, and a heat recovery device were provided through further investigation.

Means for Solving the Problems

[0008] As a result of intensive studies to solve the above problems, the present inventors found that by using polymer compound particles having an amino group as a gas absorption material, a gas absorber can be realized with a large reversible absorption amount of gas per unit volume, capable of absorbing and releasing gas at high speeds, and with the heat required for gas release being kept small. In particular, it was found that the absorption and release performance of the gas absorber can be further improved by having the following configuration. (1) A gel particle film is supported on a carrier such as a thin plate, film, or fiber made of a metal, carbon material, or polymer compound. (2) The carriers supporting the gel particle films are laminated and integrated. (3) The gel particle film is stabilized and fixed by adding a stabilizer. (4) To accelerate the absorption amount and absorption rate of the acidic gas, an absorption promoter is added to the gel particle film.

[0009] Specifically, the present invention has the following configurations. [1] A gas absorption material characterized by containing polymer compound particles having an amino group. [2] The gas absorption material according to [1], wherein the polymer compound particles are hydrogel particles. [3] The gas absorption material according to [2], wherein the polymer compound particles have a water content of 0.1 mL or more per 1 g of solid content. [4] The gas absorption material according to any one of [1] to [3] for absorbing an acidic gas from a gas containing water vapor and an acidic gas. [5] The gas absorption material according to any one of [1] to [4], wherein the polymer compound constituting the polymer compound particles is a polymer of a monomer component containing a monomer having an amino group. [6] The gas absorption material according to [5], wherein the monomer contained in the monomer component is a substituted acrylamide monomer. [7] The gas absorption material according to [5] or [6], wherein the monomer having an amino group is N-(aminoalkyl)acrylamide. [8] The gas absorption material according to any one of [5] to [7], wherein the monomer having an amino group is a monomer having a tertiary amino group. [9] The gas absorption material according to any one of [5] to [8], wherein the proportion of the monomer having an amino group in the monomer component is 5 to 95 mol%.

[10] The monomer component includes a monomer having an amino group and a monomer having a hydrophobic group, The gas absorption material according to any one of [5] to [9], wherein the molar ratio of the monomer having an amino group to the monomer having a hydrophobic group is 5:95 to 95:5.

[11] The gas absorption material according to

[10] , wherein the monomer having an amino group is N-(aminoalkyl)acrylamide and the monomer having a hydrophobic group is N-alkylacrylamide.

[12] The gas absorption material according to any one of [1] to

[11] , wherein the polymer density inside the particles in the dispersed state after swelling the polymer compound particles in water is 0.3 to 80%.

[13] The gas absorption material according to any one of [1] to

[12] , wherein the particle size of the polymer compound particles in the dry state is 5 nm to 10 μm.

[14] The polymer compound particles are those that undergo a phase transition due to a change in temperature, The gas absorption material according to any one of [1] to

[13] , wherein the phase transition temperature of the polymer compound particles is in the range of 10 to 95 °C.

[15] The gas absorption material according to any one of [1] to

[14] , wherein a crosslinked structure is formed between at least some of the polymer compound particles.

[16] The gas absorption material according to any one of [1] to

[15] , wherein the hydrodynamic particle size after swelling and dispersing the polymer compound particles in water is 10 nm to 50 μm.

[17] The gas absorption material according to any one of [1] to

[16] for absorbing and releasing gas.

[18] The gas absorption material according to

[17] for repeating the cycle of gas absorption and release.

[19] The gas absorption material according to any one of [1] to

[16] for absorbing carbon dioxide gas.

[0010]

[20] Use of polymer compound particles having an amino group for gas absorption.

[21] Use of polymer compound particles having an amino group for absorbing acidic gas from a gas containing water vapor and acidic gas.

[0011]

[22] A gas absorber comprising a gel particle film of a polymer compound having an amino group and a carrier carrying the gel particle film.

[23] The gas absorber according to

[22] , wherein the gel particle film contains the gas absorption material according to any one of [1] to

[19] .

[24] The gel particle film is a hydrogel particle film containing 10% by mass or more of water with respect to the total amount of the gel particle film, which is the gas absorber described in

[22] or

[23] .

[25] The gas absorber according to any one of

[22] to

[24] , wherein the diffusion rate of carbon dioxide gas is 0.1 mmol / m 2 / sec or more.

[26] The gas absorption material according to any one of

[22] to

[25] , wherein the absorption rate of carbon dioxide gas is 0.05 mmol / m 2 / sec or more.

[27] The gas absorber according to any one of

[22] to

[26] , wherein the carrier is in the form of a thin plate or a cylinder.

[28] The gas absorber according to any one of

[22] to

[26] , wherein the carrier is a laminate obtained by laminating a plurality of thin plates.

[29] The gas absorber according to

[27] or

[28] , wherein the thin plate is a metal foil.

[30] The gas absorber according to

[27] or

[28] , wherein the thin plate is a carbon material.

[31] The gas absorber according to

[27] or

[28] , wherein the thin plate is a resin film.

[32] The gas absorber according to any one of

[22] to

[26] , wherein the carrier is a fiber aggregate.

[33] The gas absorber according to any one of

[22] to

[26] , wherein the carrier is an integrated body obtained by laminating a plurality of fiber aggregates.

[34] The gas absorber according to

[32] or

[33] , wherein the fiber aggregate contains inorganic fibers.

[35] The gas absorber according to

[34] , wherein the inorganic fiber is a metal fiber.

[36] The gas absorber according to

[35] , wherein the metal fiber contains at least one of stainless steel fiber and aluminum fiber.

[37] The gas absorber according to

[35] , wherein the metal fiber contains nickel fiber.

[38] The gas absorber according to any one of

[35] to

[37] , wherein the metal fiber is a sintered metal fiber.

[39] The gas absorber according to

[34] , wherein the inorganic fiber is a carbon fiber.

[40] The fiber assembly is the gas absorber according to any one of

[32] to

[39] containing organic fibers.

[41] The fiber assembly is the gas absorber according to

[40] which is paper.

[42] The carrier is the gas absorber according to any one of

[22] to

[26] which is a porous body.

[43] The gas absorber according to

[42] , wherein the porous body is a foamed metal.

[44] The carrier is made of a material having a specific heat at constant pressure of 2500 KJ / (m 3 K) or less, which is the gas absorber according to any one of

[22] to

[43] .

[45] The carrier is made of a material having a thermal conductivity of 10 W / (mK) or more, which is the gas absorber according to any one of

[22] to

[44] .

[46] The carrier is the gas absorber according to any one of

[22] to

[45] , wherein its surface functions as a heat transfer surface of a heat exchanger.

[47] The carrier is the gas absorber according to any one of

[22] to

[46] , which functions as a heat exchanger.

[48] The gas absorber according to any one of

[22] to

[47] , wherein the filling rate of the gel particle film is 20% or more.

[49] The gel particle film is the gas absorber according to any one of

[22] to

[48] , which further contains a film stabilizer.

[50] The film stabilizer is the gas absorber according to

[49] , which contains a polymer compound.

[51] The film stabilizer is the gas absorber according to

[49] , which contains a polymer compound having at least one of a primary amino group, a secondary amino group, and a tertiary amino group.

[52] The film stabilizer is the gas absorber according to

[51] , which contains polyvinylamine or a derivative of polyvinylamine.

[53] The film stabilizer is the gas absorber according to any one of

[49] to

[52] , which contains a polymerizable compound.

[54] The film stabilizer is the gas absorber according to any one of

[49] to

[53] , which contains a polymer compound formed by a polymerization reaction of a polymerizable compound in the gel particle film.

[55] The gas absorber according to

[53] or

[54] , wherein the polymerizable compound is acrylamide or an acrylamide derivative.

[56] The gas absorber according to

[55] , which contains a substituted aminoalkyl acrylamide and an acrylamide derivative having two polymerizable groups as the polymerizable compound.

[57] The gas absorber according to any one of

[49] to

[56] , wherein the film stabilizer contains a crosslinking agent.

[58] The gas absorber according to

[57] , wherein the crosslinking agent is a titanium crosslinking agent.

[59] The gas absorber according to any one of

[49] to

[58] , wherein the content of the film stabilizer in the gel particle film is 1 to 89% by mass based on the total amount of the gel particle film.

[60] The gas absorber according to any one of

[22] to

[59] , wherein the gel particle film contains an absorption promoter.

[61] The gas absorber according to any one of

[22] to

[60] , wherein the gel particle film contains an amine-containing compound having a molecular weight of 61 to 10,000.

[62] The gas absorber according to

[61] , wherein the gel particle film contains at least one of an amine having an amino group and a hydroxyl group or an amine having three amino groups.

[63] The gel particle film is Isopropylaminoethanol, N,N,N’,N’-Tetramethyl-1,6-hexanediamine, Imino-bis(N,N-dimethylpropylamine) and N,N ’ ,N ” -pentamethyldiethylenetriamine, and the gas absorber according to

[61] containing at least any one of them.

[64] The gas absorber according to any one of

[22] to

[63] , wherein the surface of the gel particle film is supported on the heat transfer surface of a heat exchanger.

[65] The gas absorber according to any one of

[22] to

[64] , wherein the gel particle film can reversibly absorb at least an acidic gas.

[66] The gas absorber according to

[65] , wherein the acidic gas is carbon dioxide.

[67] The gas absorber according to

[65] , wherein the acid gas is hydrogen sulfide.

[68] The gas absorber according to any one of

[22] to

[67] , wherein the gel particle film can reversibly absorb at least water vapor.

[0012]

[69] A gas absorption method characterized by absorbing a gas into a gel particle film of a polymer compound having an amino group.

[70] The gas absorption method according to

[69] , wherein after absorbing the gas, the absorbed gas is dissipated from the gel particle film by raising the temperature of the gel particle film.

[71] The gas absorption method according to

[70] , wherein the temperature is raised until a volume phase transition of the polymer compound occurs.

[72] The gas absorption method according to

[70] or

[71] , wherein after dissipating the gas, the temperature of the gel particle film is lowered and the gel particle film is caused to absorb the gas again.

[73] The gas absorption method according to any one of

[70] to

[72] , wherein a cycle consisting of the absorption and the dissipation is repeated a plurality of times.

[0013]

[74] An acid gas absorption apparatus characterized by having the gas absorber according to any one of

[22] to

[68] .

[75] An acid gas recovery apparatus characterized by having the gas absorber according to any one of

[22] to

[68] .

[76] A water vapor absorption apparatus characterized by having the gas absorber according to any one of

[22] to

[68] .

[77] A water vapor recovery apparatus characterized by having the gas absorber according to any one of

[22] to

[68] .

[78] A heat exchanger characterized by having the gas absorber according to any one of

[22] to

[68] .

[79] A heat recovery apparatus characterized by having the gas absorber according to any one of

[22] to

[68] . [Advantages of the Invention]

[0014] According to the gas absorption material of the present invention, it is possible to realize a gas absorber that has a large reversible gas absorption amount per unit volume, can absorb and desorb gas at a high speed, and has a small amount of heat required for gas desorption. In addition, the gas absorber of the present invention has a large reversible gas absorption amount per unit volume, can absorb and desorb gas at a high speed, has high stability of its gel particle film, and can surely maintain its initial performance even when gas absorption and desorption are repeated. The acid gas absorber, acid gas recovery device, water vapor absorber, water vapor recovery device, heat exchanger, and heat recovery device of the present invention can efficiently absorb and recover acid gas and water vapor gas by having such a gas absorber, and can greatly contribute to the realization of a low-carbon society.

Brief Description of Drawings

[0015]

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Figure 39

Figure 40

Figure 41

Figure 42

Figure 43

Figure 44

Mode for Carrying Out the Invention

[0016] Hereinafter, the present invention will be described in detail. The description of the constituent elements described below may be made based on typical embodiments or specific examples, but the present invention is not limited to such embodiments. In this specification, the numerical range represented by "~" means a range including the numerical values described before and after "~" as the lower limit value and the upper limit value. Also, in this specification, "(meth)acrylamide" shall mean "acrylamide" and "methacrylamide".

[0017] <Gas Absorbing Material> The gas absorbing material of the present invention contains polymer compound particles having an amino group. When the polymer compound particles having an amino group are given a small temperature change, the degree of swelling, internal structure of the particles, or acid dissociation constant of the amino group, etc. change, and due to this change, the gas absorption capacity changes. As a result, this gas absorption material can switch between a state of absorbing gas and a state of dissipating gas. It is presumed that the switching between these two states is achieved by the following mechanism. In the following description, when absorbing and dissipating a specific gas contained in the gas to be treated, the specific gas may be referred to as the "target gas". First, when a gas is brought into contact with the polymer compound particles having an amino group at a specific temperature, an anion derived from the gas and the amino group of the polymer compound particles form a salt, and the gas is reversibly absorbed by the polymer compound particles. When the polymer compound particles are heated from this state, a slight temperature increase causes changes in the degree of swelling, internal structure of the particles, or acid dissociation constant of the amino group, etc., and due to this change, the polymer compound particles become a state where they easily dissipate gas. As a result, the gas is dissipated from the polymer compound particles, and at the same time, the amino group is regenerated in the polymer compound. When the cooling and heating to a specific temperature are repeatedly continued for the polymer compound particles in which the amino group has been regenerated, the cycle of the state of absorbing gas and the state of dissipating gas is repeated by the same mechanism as above. Due to the fact that the polymer compound particles having an amino group of the gas absorption material of the present invention have such a function, it can be effectively used as a material for a gas absorber that absorbs and dissipates gas, and also the amount of heat required for gas dissipation can be reduced. In addition, in the gas absorption material of the present invention, since the polymer compound having an amino group is in the form of particles, when the deposited film formed by depositing the particles is exposed to the gas to be treated, the gas to be treated is absorbed on the surface of the deposited film and then the absorbed carbon dioxide molecules or bicarbonate ions rapidly diffuse into the interior of the film through the gaps between the particles. Further, when the absorbed target gas is released, the carbon dioxide molecules or bicarbonate ions rapidly diffuse through the gaps between the particles, and the target gas is released from the surface of the deposited film and also from the interior of the deposited film with the formation of a gas phase in the gaps between the particles. Therefore, compared with a homogeneous gas absorber without gaps, the gas absorber formed using this gas absorption material has a larger reversible gas absorption amount per unit volume and can perform gas absorption and release at high speeds.

[0018] In the gas absorption material of the present invention, the gas to be absorbed and released is not particularly limited. However, since it forms a salt with the amino group of the polymer compound particles and is easily absorbed by the particles, it is preferably an acidic gas such as carbon dioxide or hydrogen sulfide, and more preferably carbon dioxide. Since the gas absorption material of the present invention can efficiently perform reversible absorption and release of gas by the above mechanism, it can be effectively used for the separation and recovery of acidic gases such as carbon dioxide and hydrogen sulfide, and in particular, it can be suitably used for the separation and recovery of carbon dioxide with a large emission amount. In addition, different from an adsorbent, the gas absorption material of the present invention can absorb a large amount of acidic gas even when a high concentration of water vapor is present in the gas. Therefore, for example, when treating a gas to be treated containing water vapor and carbon dioxide, carbon dioxide can be directly separated and recovered without previously removing the water vapor, and the process required for treating the gas to be treated can be simplified. Hereinafter, the polymer compound particles having an amino group used in the gas absorption material of the present invention will be described in detail.

[0019] (Chemical Structure and Preparation of Polymer Compound Particles Having an Amino Group) The polymer compound particles having an amino group are particles composed of a polymer compound having an amino group, and it is preferably composed only of the polymer compound having an amino group, but may contain materials used when preparing the particles, such as particle size adjusting components such as surfactants, crosslinking agents, unreacted monomers, and the like.

[0020] The polymer compound having an amino group is not particularly limited, and examples thereof include (meth)acrylamide-based polymers and their derivatives, polyethyleneimine and its derivatives, polyvinyl alcohol and its derivatives, polyallylamine and its derivatives, and the like. Specific constituent monomers include N,N-dimethylaminopropylmethacrylamide, N,N-diethylaminopropylmethacrylamide, N,N-dimethylaminoethylmethacrylamide, N,N-diethylaminoethylmethacrylamide, N,N-dimethylaminopropylmethacrylate, N,N-diethylaminopropylmethacrylate, N,N-dimethylaminoethylmethacrylate, N,N-diethylaminoethylmethacrylate, N,N-dimethylaminopropylacrylamide, N,N-diethylaminopropylacrylamide, N,N-dimethylaminoethylacrylamide, N,N-diethylaminoethylacrylamide, 3-aminopropylmethacrylamide hydrochloride, 3-aminopropylacrylamide hydrochloride, N,N-dimethylaminopropylacrylate, N,N-diethylaminopropylacrylate, N,N-dimethylaminoethylacrylate, N,N-diethylaminoethylacrylate, 3-aminopropylmethacrylate hydrochloride, 3-aminopropylacrylate hydrochloride, etc., and it is preferably an acrylamide-based polymer. The amino group of the polymer compound having an amino group may be any of a primary amino group, a secondary amino group, and a tertiary amino group, but it is preferable that the acid dissociation constant of their conjugate acid changes in response to stimuli such as temperature change. In particular, it is preferable that the acid dissociation constant when absorbing carbon dioxide is equal to or greater than the acid dissociation constant of carbonic acid, and the acid dissociation constant when releasing carbon dioxide is equal to or smaller than the acid dissociation constant of carbonic acid. Among them, since the release efficiency of the acidic gas can be increased, a tertiary amino group is preferable, and a dialkylamino group such as a dimethylamino group is more preferable. Further, the amino group of the polymer compound may be bonded to the main chain or the side chain, but it is preferably bonded to the side chain.

[0021] In addition, the polymer compound having an amino group preferably has a hydrophobic group. As a result, the degree of swelling and the internal structure of the polymer compound particles change significantly (phase transition) in response to temperature changes, and gases such as carbon dioxide gas can be efficiently absorbed and released in response to temperature changes. Hereinafter, the phase transition of the polymer compound particles having this amino group and hydrophobic group will be described by taking the case of absorbing and releasing carbon dioxide as the target gas as an example. FIG. 1 is a schematic diagram showing the absorption and release cycle of carbon dioxide gas when the polymer compound particles having an amino group and a hydrophobic group are hydrogel particles. As shown in the upper left of FIG. 1, at low temperatures, there is no steric hindrance around the amino group in this gel particle, and the amino group is in a state where it easily absorbs acidic gas (has high basicity). When the gas to be treated containing carbon dioxide gas is brought into contact with this gel particle, bicarbonate anions are generated by the nucleophilic attack of hydroxyanions on carbon dioxide, and one molecule of this bicarbonate anion forms a salt with one amino group. As a result, the gel particle is in a state of absorbing carbon dioxide gas. At the same time, the pH of water decreases and the gel particle swells. When the gel particle is heated from this state, the intramolecular hydrophobic interaction increases and the gel particle contracts (phase transition). As a result, the area around the amino group is covered with a polymer chain with low polarity, the steric hindrance increases, and the amino group is in a state where it easily dissipates acidic gas (has low basicity). Thereby, carbon dioxide gas is dissipated, and at the same time the pH of water rises. Next, when the gel particle is cooled, the pH of water further rises and the gel particle swells, returning to the initial state. As described above, the gel particles of the polymer compound having an amino group and a hydrophobic group can be switched from a state of absorbing acidic gas to a state of dissipating it with a slight temperature difference that causes a phase transition. Therefore, by using a gas absorption material containing such gel particles, the amount of energy required for the separation and recovery process of acidic gas can be reduced. Examples of the hydrophobic group introduced into the polymer compound include X C 2X or C X H 2X+1 represented hydrocarbon groups, and a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a tert-butyl group, a pentyl group, a cyclopentyl group, an isopentyl group, a hexyl group, a cyclohexyl group, etc. are preferable. Among them, an isobutyl group and a tert-butyl group are more preferable. Alternatively, it may be one in which a hydroxyl group is bonded to the above hydrophobic group, such as a hydroxyethyl group, a hydroxypropyl group, or a hydroxybutyl group.

[0022] The polymer compound having an amino group preferably has a polymer density in the particles in a dispersed state after swelling the polymer compound particles in water of 0.3 to 80%, more preferably 1 to 60%.

[0023] The polymer compound particles having an amino group can be prepared using a solution containing a monomer component (hereinafter, these are referred to as "particle preparation liquid"). In this specification, the "monomer component" refers to all monomers used for the synthesis of the polymer of the polymer compound particles having an amino group. The method for producing the polymer compound particles is not particularly limited, and conventionally known methods such as emulsion polymerization method, dispersion polymerization method, suspension polymerization method, and seed polymerization method can be used.

[0024] The monomer component used for the preparation of the particles contains at least a monomer having an amino group, and preferably contains a monomer having an amino group and a monomer having no amino group. That is, the polymer compound having an amino group may be a homopolymer or copolymer of a monomer having an amino group, or may be a copolymer of a monomer having an amino group and a monomer having no amino group. Thereby, by controlling the ratio of these monomers, the density of the amino group of the polymer compound particles can be adjusted to an appropriate range. The monomer having an amino group and the monomer having no amino group used as necessary are preferably substituted (meth)acrylamide monomers, and more preferably substituted acrylamide monomers.

[0025] Regarding the description and preferred range of the amino group of the monomer having an amino group, the description and preferred range of the amino group of the polymer compound having an amino group can be referred to. The number of amino groups of the monomer is not particularly limited, and may be one or two or more. When the monomer has two or more amino groups, each amino group may be the same or different. The monomer having an amino group is not particularly limited, and examples thereof include N-(aminoalkyl)acrylamide, N-(aminoalkyl)methacrylamide, etc., and N-(aminoalkyl)acrylamide is preferred.

[0026] The monomer component preferably includes a monomer having a hydrophobic group together with the monomer having an amino group. For the description and preferred range of the hydrophobic group of the monomer having a hydrophobic group, reference can be made to the description and preferred range of the hydrophobic group that can be employed in the polymer compound having an amino group. The hydrophobic group is preferably present at the terminal. The monomer having a hydrophobic group may or may not further have an amino group. The monomer having a hydrophobic group is not particularly limited, and examples thereof include N-alkylacrylamide, N-alkylmethacrylamide, N-alkylacrylate, N-alkylmethacrylate, N,N-dialkylacrylamide, N-(hydroxyalkyl)methacrylamide, N,N-dialkylacrylate, N-(hydroxyalkyl)methacrylate, N,N-dialkylmethacrylamide, N-(hydroxyalkyl)acrylamide, N,N-dialkylmethacrylate, N-(hydroxyalkyl)acrylate, etc., and N-alkylacrylamide is preferred.

[0027] As a preferable combination of a monomer having an amino group and a monomer having a hydrophobic group, a combination of N-(aminoalkyl)(meth)acrylamide and N-alkyl(meth)acrylamide can be mentioned, and a combination of N-(aminoalkyl)methacrylamide and N-alkylacrylamide is preferable. Particles composed of a copolymer of N-(aminoalkyl)(meth)acrylamide and N-alkyl(meth)acrylamide have a hydrophobic alkyl group and a hydrogen-bonding amide evenly distributed in a well-balanced manner within the molecule. For this reason, at low temperatures, they easily dissolve in water and form swollen gel particles, efficiently absorbing the gas contained in the gas to be treated. Then, when heated from the state of having absorbed the gas, with a slight temperature increase, the gel particles shrink and the absorption capacity for the gas significantly decreases, efficiently dissipating the gas. Therefore, by using the particles composed of this copolymer as a gas absorption material, gas absorption and dissipation can be performed at high speed, and the amount of heat required for gas dissipation can be kept small. In addition, the gel particles of this copolymer are less likely to precipitate even when heated above the phase transition temperature and can maintain very stable solution characteristics.

[0028] The proportion of the monomer having an amino group in the monomer component is preferably 5 to 95 mol%, more preferably 30 to 70 mol%, and even more preferably 50 to 65 mol% with respect to the total number of moles of the monomer component. Further, when the monomer component contains a monomer having a hydrophobic group, the molar ratio of the monomer having an amino group to the monomer having a hydrophobic group is preferably 95:5 to 5:95, and more preferably 2:1 to 1:2. Note that a monomer having both an amino group and a hydrophobic group is classified as a monomer having an amino group. The acid gas absorption capacity of the polymer compound tends to increase as the number of amino groups increases. However, if the number of amino groups becomes too large, due to the electrical repulsion between the amino groups, the shrinkage of the particles and the dissipation of the acid gas due to the above high temperature are less likely to occur. By setting the proportion of the monomer having an amino group and the molar ratio of the monomer having an amino group to the monomer having a hydrophobic group within the above ranges, polymer compound particles in which a phase transition easily occurs upon heating and the acid gas is efficiently dissipated can be obtained.

[0029] The particle preparation liquid may contain only the monomer component or may contain other components. Examples of other components include surfactants, crosslinking agents, polymerization initiators, etc. By using a surfactant, the concentration in the particle preparation liquid can be changed to control the particle size of the resulting polymer compound particles. Also, by using a crosslinking agent, the swelling property of the particles can be controlled so that a crosslinked structure is formed in the polymer compound within the particles and they do not swell excessively. Further, when a relatively large amount of crosslinking agent is used or when the monomer concentration during polymerization is set relatively high, a crosslinked structure can also be formed between the particles. Thereby, a relatively large continuous void structure is formed between the composite particles linked by the crosslinked structure, and the absorption and dissipation of gas can be promoted. As the surfactant, a cationic surfactant such as cetyltrimethylammonium bromide can be used. The crosslinking agent only needs to be able to form a crosslinked structure between the monomers to be used, and N,N'-alkylenebisacrylamide can preferably be used. The number of carbon atoms in the alkylene group of N,N'-alkylenebisacrylamide is not particularly limited, but is preferably 1 to 12, more preferably 1 to 4, and even more preferably 1 to 2. Instead of the alkylene group, a crosslinking agent in which oligoethyleneimine or oligoethylene glycol functions as a crosslinking agent chain may also be used.

[0030] The solvent of the particle preparation liquid is not particularly limited, and examples include polar solvents such as water, methanol, ethanol, isopropanol, acetonitrile, N,N-dimethylformamide, and dimethyl sulfoxide, and a mixed solvent in which two or more of these polar solvents are combined may also be used. Among them, it is preferable to use water or a mixed solvent of water and another polar solvent.

[0031] (Properties of Polymer Compound Particles Having Amino Groups) The polymer compound particles having an amino group may be gel particles swollen with a liquid or dry particles (solid particles), but gel particles are preferred. In the gel particles, since gas dissolves in the liquid contained in the gel particles, the amino groups inside the gel particles can also contribute to the absorption of gas. Thereby, a large reversible absorption amount of gas can be obtained.

[0032] The polymer compound particles preferably have a particle size in the range of 5 nm to 10 μm in the dry state. The hydrodynamic particle size after swelling the polymer compound particles in water is preferably from ten nm to several tens of μm, more preferably from 10 nm to 50 μm, and even more preferably from 20 nm to 10 μm, specifically the hydrodynamic diameter in water measured by dynamic light scattering method. The "particle size after swelling in water" of the polymer compound particles refers to the particle size after immersing the dried polymer compound particles in water for 24 hours and is the average particle size measured by dynamic light scattering method. When the particle size of the polymer compound particles during drying and after swelling is within the above range, the reversible absorption amount of gas per unit volume, the absorption rate and the desorption rate of gas can be sufficiently increased.

[0033] The liquid contained in the gel particles is not particularly limited, and examples thereof include polar solvents such as water, methanol, ethanol, isopropanol, acetonitrile, N,N-dimethylformamide, and dimethyl sulfoxide, and a mixed solvent in which two or more of these polar solvents are combined may also be used. Among them, it is preferable to use water or a mixed solvent of water and another polar solvent. That is, the gel particles are preferably hydrogel particles. When the gel particles are hydrogel particles, gas can be efficiently dissolved in the particles, and a larger volume of gas can be reversibly absorbed. The water content in the gel particles is preferably 0.1 mL or more, more preferably 0.5 mL or more, and even more preferably 1 mL or more per 1 g of the solid content. Also, the water content in the gel particles is preferably 20 mL or less, more preferably 10 mL or less, and even more preferably 8 mL or less. By setting the water content of the gel particles within the above range, it is possible to suppress excessive swelling of the gel particles, sufficiently dissolve the gas in the gel particles, and increase the absorption amount and the dissipation amount of the gas.

[0034] The polymer compound particles having an amino group used in the present invention preferably have a gas absorption ability that changes in response to stimuli such as temperature changes. Examples of factors that change the gas absorption ability include changes in the acid dissociation constant of the functional group, changes in the three-dimensional structure, changes in the degree of swelling, changes in hydrophilicity, changes in water content, changes in the amount of dissolved bicarbonate ions, changes in the amount of dissolved hydrogen sulfide ions, and the like. The polymer compound particles having an amino group may have a gas absorption ability that changes due to any factor, but preferably, at least the acid dissociation constant of ammonium ions, which are the conjugate acids of amino groups, changes in response to temperature changes, thereby changing the gas absorption ability. In particular, it is preferable that the change in the acid dissociation constant is caused by the swelling and shrinkage (volume phase transition) of the gel in response to temperature changes, the coil-globule structure transition of the polymer in response to temperature changes, or the change in the hydrophilicity and hydrophobicity of the molecule. Thereby, according to the mechanism shown in FIG. 1, the gas absorption ability of the polymer compound particles can be greatly changed by a small temperature change, and the amount of energy required for gas absorption and dissipation can be reduced.

[0035] The phase transition temperature of the polymer compound particles is preferably from 10 to 95°C, more preferably from 20 to 90°C, and even more preferably from 30 to 80°C. In the present specification, the "phase transition temperature" means the temperature at which the acid dissociation constant of the ammonium ion, which is the conjugate acid of the amino group, is equal to or smaller than the acid dissociation constant of carbonic acid, or the temperature at which the particle size of the polymer compound particles in water becomes 30% or more smaller than the particle size at 5°C. This phase transition temperature can be determined by immersing the polymer compound particles in water at 5°C and gradually measuring the pH or particle size of the polymer compound particle aqueous solution at regular temperature intervals or continuously while raising the water temperature from 15°C. The particle size of the polymer compound particles can be measured by the dynamic light scattering method.

[0036] <Gas absorber> The gas absorber of the present invention has a gel particle film of a polymer compound having an amino group and a carrier carrying the gel particle film. The gel particle film used in the present invention is a film containing gel particles obtained by swelling solid particles of a polymer compound having an amino group with water. Confirmation that it is a gel particle film can be carried out by visualizing the gel particle film by adding fluorescently modified gel particles and observing this with a confocal laser microscope. Fluorescent modification of the gel particles can be carried out by introduction of 4-Acrylamidofluorescein or the like. The gel particle film may be a particle deposition film in which the gel particles are deposited so as to form a layer on the carrier, or may be one in which the gel particles enter between the fibers or pores constituting the carrier and form a layer. Regarding the description and preferred range of the polymer compound having an amino group and its gel particles, reference can be made to the description and preferred range of the polymer compound having an amino group and its gel particles in the gas absorption material.

[0037] This gel particle film can be formed, for example, by applying a particle solution in which polymer compound particles having amino groups are dissolved in a polar solvent onto a carrier, drying to form a film of solid polymer compound particles, and adding water to the film of the polymer compound particles to swell it. At this time, a polymerizable compound and a polymerization initiator may be added to the particle solution, and after coating and drying, the polymerizable compound may be polymerized, and then water may be added to swell it. Regarding the polymerizable compound to be added, reference can be made to the description of the stabilizer described later. The polymerization initiator may be any one that can initiate the polymerization of the polymerizable compound, and may be a photoinitiator or a thermal polymerization initiator. A photoinitiator is preferred. When a photoinitiator is used, polymerization is initiated by irradiating active energy rays such as ultraviolet rays. By performing such polymerization, a gel particle film with high stability and not overly swelling can be produced. As the polar solvent of the particle solution, any of the polar solvents exemplified as those to be contained in the above gel particles can be used, and among them, it is preferable to use water or a mixed solvent of water and other polar solvents. The water content in the gel particle film is preferably 10% by mass or more, more preferably 50 - 2000% by mass, based on the total amount of the gel particle film. The thickness of the gel particle film is not particularly limited, but is preferably 1 - 1000 μm, more preferably 10 - 600 μm, and even more preferably 20 - 400 μm. By setting the thickness of the gel particle film within the above range, the reversible absorption amount of gas per unit volume can be made sufficient, and the absorption and desorption of gas can be performed at a high speed. In addition, when the gel particles form a layer in a state of entering between the fibers or pores constituting the carrier, the thickness of the gel particle layer on the fiber surface or pore surface corresponds to the thickness of the above gel particle film.

[0038] The gel particle film preferably has a carbon dioxide gas diffusion rate of 0.1 mmol / m 2 / sec or more, more preferably 0.15 mmol / m 2 / sec or more, and even more preferably 0.2 mmol / m 2More preferably, it is at least / sec. Further, the absorption rate is preferably at least 0.05 mmol / m 2 / sec, more preferably at least 0.1 mmol / m 2 / sec, and even more preferably at least 0.2 mmol / m 2 / sec. In this specification, the "carbon dioxide gas absorption rate of the gel particle film" is determined by measuring the amount of carbon dioxide in the outlet gas using gas chromatography or an infrared carbon dioxide concentration meter when a nitrogen gas (mixed gas) containing 10% carbon dioxide is humidified and passed through at 60°C on the surface of the gel particle film. Further, the above-mentioned diffusion rate and absorption rate are the results for the gel particle film when 5 mol% of DMAPM is introduced, and they will be even greater when the amount of DMAPM is large or when an accelerator is added.

[0039] [Components other than polymer compound particles having an amino group] The gel particle film may contain a polymer compound other than the polymer compound having an amino group and an additive. The polymer compound other than the polymer compound having an amino group is not particularly limited, but is preferably a polymer compound that reacts to stimuli such as temperature changes. Examples of the reaction to stimuli include changes in the acid dissociation constant of a functional group, changes in the three-dimensional structure, changes in the degree of swelling, changes in hydrophilicity, changes in water content, changes in the amount of bicarbonate ion dissolved, and changes in the amount of hydrogen sulfide ion dissolved.

[0040] Examples of the additive include a film stabilizer, an absorption promoter, and a diffusion promoter. Examples of the film stabilizer include a polymer compound, a polymerizable molecule (polymerizable compound), a cross-linking agent such as a titanium cross-linking agent, a primary amine, and a secondary amine. Among these, as the polymer compound, a polymer compound having a primary amino group such as polyvinylamine, a polymer compound having a secondary amino group, a polymer compound having a tertiary amino group, a polymer compound having a plurality of types of primary, secondary, and tertiary amino groups, polyvinyl alcohol, polyethylene, a polyvinyl alcohol / polyethylene copolymer, etc. can be preferably used. Also, when a polymerizable molecule is used as the membrane stabilizer, the polymer compound generated by the polymerization reaction of this molecule within the gel particle membrane also functions as a membrane stabilizer. As a result, even after water addition or gas absorption / dissipation after membrane formation, it becomes easier to maintain a uniform membrane shape without excessive swelling. Examples of the polymerizable molecule include monomers having a polymerizable group, and for example, acrylic monomers can be exemplified. Among them, acrylamide or acrylamide derivatives can preferably be used. For example, alkyl acrylamide, substituted or unsubstituted aminoalkyl acrylamide, acrylamide derivatives having two polymerizable groups, etc. can be mentioned. Among these, substituted aminoalkyl acrylamide and acrylamide derivatives having two polymerizable groups can preferably be used. It is preferable to use a substituted aminoalkyl acrylamide and an acrylamide derivative having two polymerizable groups in combination, and the molar fraction thereof is preferably 60 - 99:40 - 1, more preferably 80 - 99:20 - 1, and even more preferably 90 - 99:10 - 1. Specific examples of the monomer having a polymerizable group include N-isopropylacrylamide (NIPAM), tert-butylacrylamide (TBAM), N,N-dimethylaminopropylmethacrylamide (DMAPM), N,N'-methylenebisacrylamide (BIS), acrylamide, etc. These polymerizable compounds may be used alone or in combination of two or more. When using two or more in combination, for example, a combination of N,N-dimethylaminopropylmethacrylamide (DMAPM) and N,N'-methylenebisacrylamide (BIS) can be cited as a preferred example. The content of the membrane stabilizer in the gel particle membrane is preferably 1 - 89% by mass based on the total amount of the gel particle membrane.

[0041] The absorption promoter is a compound having a function of promoting the absorption of acidic gas into the gel particle film. The dissipation promoter is a compound having a function of promoting the dissipation of acidic gas from the polymer compound particles. In the present invention, it is preferable to use an absorption-dissipation promoter having both the functions of an absorption promoter and a dissipation promoter. These absorption promoters, dissipation promoters, and absorption-dissipation promoters may each also have a function as a film stabilizer. The total content of the absorption promoter, dissipation promoter, and absorption-dissipation promoter in the gel particle film is preferably 1 to 20% by mass based on the total amount of the gel particle film. The content of the absorption promoter in the gel particle film is preferably 0.1 to 12 N in terms of amine concentration, more preferably 1 to 10 N, and even more preferably 3 to 9 N. As the absorption promoter, dissipation promoter, and absorption-dissipation promoter, low-molecular-weight amines can preferably be used. The molecular weight of the low-molecular-weight amine is preferably 61 to 10,000, more preferably 75 to 1,000, and even more preferably 90 to 500. The boiling point of the low-molecular-weight amine is preferably 80°C or higher, more preferably 120°C or higher, and even more preferably 150°C or higher because it can be repeatedly used and is practical.

[0042] The low-molecular-weight amine may contain any of a primary amino group, secondary amino group, and tertiary amino group, and may contain a plurality of amino groups, preferably 1 to 3. Also, the secondary amino group or tertiary amino group may be a cyclic amino group. Furthermore, the low-molecular-weight amine may contain a functional group other than an amino group, for example, a hydroxyl group. The number of hydroxyl groups contained in the low-molecular-weight amine is preferably 0 to 2. Preferred low-molecular-weight amines can include amines having an amino group and a hydroxyl group, amines having three amino groups, etc. More preferred low-molecular-weight amines can include amines having a secondary amino group and a hydroxyl group, etc. Amines having a secondary amino group and a hydroxyl group with a boiling point of 150°C or higher are particularly preferred because they can particularly significantly increase the dissipation amount of acidic gas in a high concentration region and are suitable for repeated use. Examples of the low-molecular-weight amine include specific compounds represented by the following formula. In addition, the absorption and dissipation promoter used in Example (9) can also be preferably used.

[0043] [Chemical formula]

[0044] Among these, in particular, since the emission amount of the acidic gas can be increased, it is preferable to use DMAE, IPAE, Bis(2DMAE)ER, 1-2HE-PRLD, 1-2HE-PP, TM-1,4-DAB, TMHAD, PMDETA. Among them, since the boiling point is relatively high and it is difficult to evaporate, it is more preferable to use IPAE, Bis(2DMAE)ER, 1-2HE-PP, TM-1,4-DAB, TMHAD, PMDETA. Since the emission amount of the acidic gas can be significantly increased by increasing its concentration, it is even more preferable to use IPAE, TM-1,4-DAB, TMHAD, PMDETA. Since they are easily available, it is particularly preferable to use IPAE, TMHAD, PMDETA. Furthermore, in a high-concentration region, the emission amount of the acidic gas can be particularly dramatically increased, and the emission amount of the acidic gas can be increased even in a situation where the amount of water relative to the amine is small. In this regard, it is most preferable to use IPAE. The additives described above may be used alone or in combination of two or more.

[0045] The gel particle film configured as described above reversibly absorbs gas under certain conditions, dissipates gas in response to stimuli such as temperature changes, and further returns to the above certain conditions or reversibly absorbs gas by applying other stimuli. Examples of the gas reversibly absorbed by the gel particle film include acidic gases such as carbon dioxide and hydrogen sulfide, and water vapor.

[0046] [Carrier] The gas absorber of the present invention is also characterized in that the gel particle film is held on the carrier. The gel-like membrane has lower fluidity compared to liquids and is less prone to convection. Therefore, in the process of absorbing acidic gas in the gel-like membrane, the diffusion process of its ions becomes the rate-determining step, and the diffusion of ions from the membrane surface to a depth of several hundred micrometers or more is restricted. As a result, the amount of acidic gas that the gel-like membrane can absorb is also limited. On the other hand, when the gel particle membrane is supported on a suitable carrier, as described above, the diffusion of the gas to be treated into the membrane through the voids between the particles and the diffusion of the acidic gas from inside the membrane are realized. Moreover, since heat is efficiently transferred to the gel particle membrane through this carrier, the temperature of the entire gel particle membrane changes responsively to external temperature changes. Also, by laminating the carriers, a large amount of gel particle membranes with a membrane thickness of several hundred micrometers or less can be filled into a reactor of a certain volume. As a result, the absorption rate and desorption rate of acidic gas and water vapor gas increase, and the acidic gas diffuses to the deep part of the membrane, enabling a large gas absorption amount to be obtained. Further, being supported on the carrier makes the gel particle membrane less likely to collapse, and the shape of the gel particle membrane can be stably maintained. Additionally, a large amount of gas can be reversibly absorbed in a reactor of a certain volume.

[0047] As the carrier, thin plates or fiber aggregates can be used. In the present invention, the "thin plate" refers to a flat plate, sheet, or foil with a thickness of 2 mm or less and 5 μm or more. The material of the thin plate preferably has a specific heat at constant pressure of 2500 KJ / (m 3 K) or less, and also preferably has a thermal conductivity of 10 W / (mK) or more. A thin plate having such thermal properties changes its temperature responsively to external temperature changes and can efficiently transfer the temperature change to the entire gel particle membrane. Here, in this specification, the "specific heat at constant pressure" is a value measured by a calorimeter such as a water calorimeter or a differential scanning calorimeter. Also, the "thermal conductivity" is a value measured by a laser flash method or a steady-state heat flow method.

[0048] As the thin plate, a metal thin plate (metal foil), a sheet made of a carbon material, a carbon sheet, a resin film (polymer compound film), etc. can be used. Examples of the sheet made of a carbon material include a graphite sheet, etc., and examples of the resin film include polyethylene, polypropylene, PET, polyimide, etc. Since it has a high thermal conductivity, it is preferable to use an aluminum thin plate, an iron thin plate, or a graphite sheet as the thin plate. Alternatively, since it has a low specific heat, it is preferable to use an aluminum thin plate, a graphite sheet, or a resin film. Examples of the metal thin plate include a stainless steel thin plate, an iron thin plate, an aluminum thin plate, or a nickel thin plate, etc. Among these, since it has a relatively high thermal conductivity, it is preferable to use an iron thin plate, an aluminum thin plate, or a nickel thin plate, and it is more preferable to use a nickel thin plate.

[0049] The thin plate may be a plate body with a homogeneous internal structure, or may be a porous body or a honeycomb structure body. In the case of a porous body or a honeycomb structure body, since the pores can be filled with a gel particle film, the heat of the thin plate can be easily transferred to the gel particle film, and the responsiveness of the gas absorber to temperature changes can be enhanced. In particular, the porous bodies of foamed metal, foamed nickel, and porous carbon have high heat transfer properties to the gel particle film, and by using this as a carrier, the responsiveness of the gas absorber to temperature changes can be greatly enhanced. The pore diameter of the porous body such as foamed metal is preferably 0.1 to 10 mm, and more preferably 0.4 to 4 mm. Also, the specific surface area is preferably 100 to 10000 m 2 / m 3 and more preferably 200 to 6000 m 2 / m 3 . Also, when using a carrier made of a porous resin or a porous carbon as the porous carrier, the heat capacity is small, so the thermal efficiency of the absorber can be improved. The porosity of the porous body used as the carrier is preferably 1 to 99%, more preferably 10 to 99%, and even more preferably 20 to 95%. In this specification, the "porosity of the thin plate" means the porosity measured by the apparent volume, mass of the thin plate, and the density of the material. Further, the carrier may be a laminate in which a plurality of these thin plates are laminated. In the laminate, all the thin plates may be the same, or a plurality of thin plates having different materials and thicknesses may be combined.

[0050] The fiber aggregate is obtained by processing a large number of fibers into a thin and wide plate shape. Examples of the fiber aggregate include cloth, paper, etc., and among them, a porous material such as a filter is preferably used. The cloth may be any of woven fabric, felt, non-woven fabric, etc. Further, a sintered metal fiber felt can also be preferably used as the carrier. This is a shape in which fibers, which are fiber sintered bodies, are densely aggregated, and high heat conductivity can be obtained. For example, a sintered felt made of stainless steel fibers or a sintered felt made of nickel fibers can be preferably used, and among them, a sintered felt made of nickel fibers can be particularly preferably used. The fibers used for the fiber aggregate preferably have a specific heat capacity at constant pressure of 2500 KJ / (m 3 K) or less, and also preferably have a thermal conductivity of 10 W / (mK) or more. A fiber aggregate having such thermal properties changes its temperature responsively according to an external temperature change, and can efficiently transmit the temperature change to the entire gel-like film.

[0051] The fibers used for the fiber aggregate may be inorganic fibers, organic fibers, or composite fibers combining inorganic fibers and organic fibers. Examples of the inorganic fibers include metal fibers such as stainless steel fibers, aluminum fibers, and nickel fibers, and carbon fibers, etc., and nickel fibers are preferred because high heat conductivity can be obtained. As the organic fibers, natural fibers such as cotton and hemp, and synthetic fibers such as rayon and polyester can all be used. The diameter of the fiber is not particularly limited, but is preferably 8 to 100 μm. Thereby, a gel particle film excellent in gas absorption performance and dissipation performance can be obtained. Further, the carrier may be an assembly in which a plurality of these fiber assemblies are laminated. In the assembly, all of the fiber assemblies may be the same, or a plurality of fiber assemblies having different fiber types, fiber diameters, fiber densities, etc. may be combined. Further, the carrier may be a laminate in which a thin plate and a fiber assembly are laminated.

[0052] When using a fiber assembly as the carrier, the filling rate of the gel particle film is preferably 10 to 100%, more preferably 15 to 80%, and even more preferably 20 to 70%. The filling rate of the gel particle film here refers to the occupancy rate of the gel particle film with respect to the total volume of the gas absorber. Thereby, the gel particle film can efficiently absorb and dissipate gas. In particular, when using a sintered body, even with a high filling rate, it is possible to maintain a high gas absorption and dissipation ability of the gel particle film. For example, even when the filling rate is 60% or more, it is possible to maintain a high gas absorption and dissipation ability.

[0053] The shape of the carrier is not particularly limited and can be appropriately selected according to the application. Specific examples of the shape of the carrier include plate shape, cylindrical shape, etc. The planar shape of the plate and the cross-sectional shape of the cylinder may be any of polygonal shapes such as square shape, rectangular shape, circular shape, elliptical shape, etc.

[0054] <Gas absorption method> The gas absorption method of the present invention is a method of absorbing gas into the amino groups in the gel particle film. For the description of the gel particle film of the polymer compound having an amino group, reference can be made to the description of the gel particle film in the above <Gas absorber>. When the amino groups inside the gel particle film come into contact with the gas at a specific temperature, an acid derived from the gas reacts with a base derived from the amino group of each gel particle to form a salt, thereby efficiently absorbing the gas. In addition, the gas emission from this gel particle film can be achieved by raising the temperature of the gel particle film. When the temperature of the gel particle film is raised, the basicity inside the gel particle film decreases. Also, the pKa of the conjugate acid of the amine in the gel particle film decreases. Furthermore, the hydrophobic interaction of each gel particle increases, each gel particle shrinks, that is, a volume phase transition occurs in the gel particle, and the steric hindrance around the amino group increases. As a result of the above, gas is emitted from the gel particle film. After that, when the temperature of the gel particle film is lowered, the basicity inside the gel particle film increases. Also, the pKa of the conjugate acid of the amine in the gel particle film increases. Furthermore, the particles swell again, and the gel particle film returns to the state before the phase transition. The gel particle film that has returned to the state with increased basicity can absorb gas again. Then, when the temperature is raised, the absorbed gas is emitted by the same mechanism as above. After that, subsequently, by repeatedly lowering and raising the temperature, a cycle of gas absorption and emission is synchronously repeated. By repeatedly performing such gas absorption and emission, it becomes possible to separate and recover a specific gas even from, for example, a large volume of exhaust gas. For the detailed mechanism of the phase transition of the gel particle and the absorption and emission of gas, reference can be made to FIG. 1 and the description of FIG. 1 in the column of <Gas Absorbing Material>. In order to perform gas absorption and emission by such a mechanism, it is important to raise the temperature of the gel particle film that has absorbed gas until the basicity decreases. In particular, it is important to raise the temperature until the basicity becomes equal to or lower than the pKa of carbonic acid. If this temperature increase is insufficient, the gas absorbed by the gel particle film cannot be sufficiently emitted, and the subsequent gas absorption rate, emission rate, and reversible absorption amount will become small. For example, when the gel particle is a gel particle of a (meth)acrylamide-based polymer, the temperature of the gel particle film during gas absorption is preferably 1 to 60°C, and the temperature of the gel particle film during gas emission is preferably 40 to 200°C.

[0055] <Application of Gas Absorbent> As described above, the gas absorber of the present invention can absorb and release gases such as carbon dioxide at high speed and has a large gas absorption capacity. Therefore, it can be suitably used as a gas absorber for an acid gas absorption device, an acid gas recovery device, a water vapor absorption device, a water vapor recovery device, and the like. Further, the gas absorber of the present invention can also function as a heat transfer surface of a heat exchanger or the heat exchanger itself for the carrier, and can also be effectively applied to a heat exchanger or a heat recovery device. In this case, for example, a gel-like film is provided on the surface of the carrier (the surface of the heat transfer surface) that functions as a heat transfer surface.

[0056] Hereinafter, as an example of an acid gas recovery device to which the gas absorber of the present invention is applied, a first embodiment and a second embodiment of a carbon dioxide gas recovery device will be described. FIG. 2 is a schematic diagram showing the carbon dioxide gas recovery device of the first embodiment, and FIG. 3 is a schematic diagram showing the carbon dioxide gas recovery device of the second embodiment.

[0057] As shown in FIG. 2, the carbon dioxide gas recovery device of the first embodiment includes a heat exchanger 21, a desulfurizer 22, a columnar gas absorber 23, and first to third pipes 24, 25, 26 connected to each of these parts. One end of the first pipe 24 is a gas inlet for introducing exhaust gas (gas to be treated), and the other end is connected to the desulfurizer 22. One end of the second pipe 25 is connected to the desulfurizer 22, and the other end is connected to one side surface of the gas absorber 23. The third pipe 26 has a circulation path 26a connected to one side surface and the other side surface of the gas absorber 23, and a branch path 26b branching from the circulation path 26a on one side surface side of the gas absorber 23. One end of the branch path 26b is a gas outlet for discharging the recovered carbon dioxide gas. In addition, the connection portions of the second pipe 25 and the third pipe 26 on one side surface of the gas absorber 23 are provided so as to sandwich the central portion on substantially the same diameter of the circular side surface. The heat exchanger 21 is connected to an intermediate portion of the first pipe 24 and an intermediate portion of the circulation path 26a, respectively. The gas absorber 23 is constituted by the gas absorber of the present invention. In the present embodiment, the gas absorber 23 includes a carrier formed of a columnar honeycomb rotor obtained by processing a fiber assembly into a honeycomb shape, and a gel particle film supported on the carrier, and is configured to be continuously rotationally driven about the center of the disk as a rotation axis. The gas absorber 23 has a temperature approximately the same as the ambient temperature when the operation of the carbon dioxide gas device is OFF.

[0058] To recover carbon dioxide gas from the exhaust gas using this acid gas recovery device, the operations of each part are turned ON, and the high-temperature exhaust gas after dust collection is introduced from one end of the first pipe 24. The introduced exhaust gas passes through the first pipe 24 and is introduced into the desulfurizer 22 having a cooling capacity up to about 30°C. Here, the desulfurizer and the cooler may be separate devices. When passing through the first pipe 24, part of the heat of the exhaust gas is transmitted to the circulation path 26a of the third pipe 26 via the heat exchanger 21, and the gas in the circulation path 26a is heated to about 75°C. The exhaust gas introduced into the desulfurizer 22 is subjected to a desulfurization treatment in the desulfurizer 22 and then flows into the second pipe 25. The mixed gas flowing into the second pipe 25 has a temperature of about 30°C, and is introduced into the gas absorber 23 near this temperature. In the gas absorber 23, since the temperature of the mixed gas is about 30°C, carbon dioxide is efficiently absorbed by the gel particle film in the region where the mixed gas contacts, and the gas other than the carbon dioxide gas is discharged to the outside of the gas absorber 23. On the other hand, the region of the gas absorber 23 that has absorbed carbon dioxide moves to the vicinity of the connection part of the third pipe 26 due to the rotation of the gas absorber 23 and contacts the gas introduced from the circulation path 26a of the third pipe 26. Since the gas introduced from the circulation path 26a is heated to about 75°C by heat exchange with the exhaust gas, in the gas absorber 23 in the region where the gas contacts, the gel particle film undergoes a phase transition and the carbon dioxide gas is dissipated. A part of the dissipated carbon dioxide gas flows into the branch path 26b of the third pipe 26 and is discharged to the outside from the gas discharge port of the branch path 26b and recovered. Another part of the dissipated carbon dioxide gas flows into the circulation path 26a of the third pipe 26. The carbon dioxide flowing into the circulation path 26a is heated by the heat exchanger 21 in the middle of the circulation path 25a and then re-introduced into the gas absorber 23, and the heat is used for heating the gel particle film.

[0059] As described above, in the carbon dioxide gas recovery apparatus of this first embodiment, the heat of the exhaust gas is reused to heat the gas absorber, and switching is performed from the state of absorbing the acid gas to the state of releasing it. In this embodiment, in order to effectively utilize the heat of the exhaust gas, the energy consumption in the separation and recovery process of carbon dioxide gas can be significantly reduced. When the temperatures of the exhaust gas and the absorber cannot be controlled to temperatures suitable for the absorption and release of carbon dioxide in the first embodiment, temperature control can be improved by adding a heat exchange mechanism with the outside or an additional heating mechanism to the piping and the absorber.

[0060] Next, a second embodiment of the carbon dioxide gas recovery apparatus will be described. As shown in FIG. 3, the acid gas recovery apparatus of the second embodiment includes a first heat exchanger 31, a second heat exchanger 32, a desulfurizer 33, a first tank 34 and a second tank 35, and a first pipe 36 and a second pipe 37 connected to each of these parts. One end of the first pipe 36 is a gas inlet for introducing exhaust gas (gas to be treated), and the other end is connected to a desulfurizer 33 having a cooling function. Here, the desulfurizer and the cooler may be separate devices. The second pipe 37 has a main path 37a connected to one end thereof, and a first path 37b and a second path 37c branching at the other end of the main path 37a. One end of the first path 37b communicates with the main path 37a, and the other end is connected to the first tank 34. One end of the second path 37c communicates with the main path 37a, and the other end is connected to the second tank 35. Valves (not shown) for opening and closing the respective paths 37b and 37c are provided near the other ends of the first path 37b and the second path 37c. The first heat exchanger 31 is connected to a first intermediate portion of the first pipe 36 and the first tank 34, respectively, and the second heat exchanger 32 is connected to a second intermediate portion of the first pipe 36 and the second tank 35, respectively. In the carbon dioxide gas recovery device of the second embodiment, gel particle films 38 and 39 are respectively coated on the heat exchange surfaces of the first heat exchanger 31 in the first tank 34 and the heat exchange surfaces of the second heat exchanger 32 in the second tank 35. In this embodiment, the first heat exchanger 31 in the first tank 34, the second heat exchanger 32 in the second tank 35, and the gel particle films 38 and 39 loaded in these tanks constitute the gas absorber of the present invention, and function as an absorption tower and a desorption tower for carbon dioxide gas respectively. The gel particle films 38 and 39 in each of the tanks 34 and 35 are at a temperature approximately the same as the ambient temperature (about 30°C) when the operation of the carbon dioxide gas device is OFF.

[0061] To recover carbon dioxide gas from the exhaust gas using this carbon dioxide gas recovery device, first, the valve of the first path 37b of the second pipe 37 is opened, the valve of the second path 37c of the second pipe 37 is closed, the first heat exchanger 31 is in the OFF state, and the second heat exchanger 32 is in the ON state. In this state, the first tank 34 functions as an absorption tower. That is, in this state, when the high-temperature dust-removed exhaust gas is introduced from one end of the first pipe 36, the introduced exhaust gas passes through the first pipe 36 and is introduced into the desulfurizer 33. When passing through the first pipe 36, part of the heat of the exhaust gas is transferred to the second tank 35 through the second heat exchanger 32, and the exhaust gas is cooled. The exhaust gas introduced into the desulfurizer 33 is subjected to desulfurization treatment in the desulfurizer 33 having a cooling capacity, and after being further cooled, it flows into the main path 37a of the second pipe 37. The mixed gas flowing into the main path 37a is at about 30°C, and at this temperature range, it is introduced into the first tank 34 through the main path 37a and the first path 37b. In the first tank 34, due to the temperature of the mixed gas being about 30°C, carbon dioxide is efficiently absorbed by the gel particle film 38, and the gas other than carbon dioxide is discharged to the outside through the gas discharge port provided in the first tank 34.

[0062] After allowing the gel particle film 38 to sufficiently absorb carbon dioxide, the valve of the first path 37b of the second pipe 37 is closed, the valve of the second path 37c of the second pipe 37 is opened, the first heat exchanger 31 is switched to the ON state, and the second exchanger 32 is switched to the OFF state. As a result, the heat of the exhaust gas passing through the first pipe 36 is transferred to the first tank 34 and the gel particle film 38 via the first heat exchanger 31. The gel particle film 38 in the first tank 34 is heated to about 75°C by the heat from the first heat exchanger 31 and dissipates carbon dioxide gas. The dissipated carbon dioxide gas is discharged from the gas outlet provided in the first tank 34 and recovered. On the other hand, into the second tank 35, a mixed gas at about 30°C that has flowed into the second pipe 37 through the same path as above is introduced through the second path 37c, and carbon dioxide is absorbed by the gel particle film 39 loaded in the tank 35. That is, in this state, the first tank 34 functions as a stripping tower and the second tank 35 functions as an absorption tower, and the absorption and dissipation of carbon dioxide gas are performed in parallel.

[0063] After sufficiently dissipating the carbon dioxide gas from the gel particle film 38 and absorbing the carbon dioxide gas into the gel particle film 39, as shown in FIG. 3, the valve of the first path 37b of the second pipe 37 is opened, the valve of the second path 37c of the second pipe 37 is closed, the first heat exchanger 31 is switched to the OFF state, and the second heat exchanger 32 is switched to the ON state, so that the first tank functions as an absorption tower and the second tank functions as a stripping tower. As a result, in the towers opposite to those before the switching, the absorption and dissipation of carbon dioxide gas are performed in parallel, respectively. Further, by repeating the switching operation as described above, the absorption and dissipation of carbon dioxide gas in the exhaust gas can be continuously performed, and carbon dioxide gas can be efficiently separated and recovered from a large amount of exhaust gas.

[0064] As described above, also in the carbon dioxide gas recovery apparatus of this second embodiment, the heat of the exhaust gas is reused to cause a phase transition of the gas absorber, and switching is performed from a state in which the acid gas is absorbed to a state in which it is dissipated. Therefore, the energy utilization efficiency can be greatly improved as compared with the case of using a conventional carbon dioxide gas separation and recovery process. When the temperatures of the exhaust gas and the absorber in the second embodiment cannot be controlled to temperatures suitable for the absorption and dissipation of carbon dioxide, temperature control is improved by adding a heat exchange mechanism with the outside or an additional heating mechanism to the piping and the absorber.

Example

[0065] The features of the present invention will be described more specifically below with reference to examples and comparative examples. The materials, amounts used, ratios, treatment contents, treatment procedures, etc. shown in the following examples can be appropriately changed without departing from the spirit of the present invention. Therefore, the scope of the present invention should not be construed as being limited by the specific examples shown below.

[0066] [I] Synthesis of amine-containing gel particles Polymer compound particles containing amino groups were synthesized as follows. In the following description, the gel of the polymer compound particles containing amino groups may be referred to as "amine-containing gel particles", and the particles obtained by drying the "amine-containing gel particles" may be referred to as "amine-containing dried gel particles".

[0067] (Synthesis Example 1) Add 1 liter of pure water to a 2-liter three-necked flask, heat it to 70 °C, and then dissolve 2 mM of a surfactant (cetyltrimethylammonium bromide) and three types of monomers so that the total monomer concentration becomes 312 mM. The composition of the three types of monomers is 55 mol% of N-(dimethylaminopropyl)methacrylamide, 43 mol% of N-tert-butylacrylamide, and 2 mol% of N,N'-methylenebisacrylamide. For N-(dimethylaminopropyl)methacrylamide, the one from which the polymerization inhibitor was removed using an alumina column was used. N-tert-butylacrylamide was previously dissolved in a small amount of methanol to make a 0.68 g / mL solution and then added. While maintaining this mixture at 70 °C, stir it with a mechanical stirrer and bubble nitrogen gas for 1 hour to remove the oxygen in the system. To the monomer solution thus obtained, add a solution prepared by dissolving 700 mg of 2,2'-azobis(2-methylpropionamidine)dihydrochloride in 5 mL of pure water, and react it at 70 °C for 3 hours under a nitrogen atmosphere. After the reaction, filter the precipitate and perform dialysis for 3 days using a dialysis membrane (MWCO 12 - 14,000, width: 75 mm, vol / length: 18 mL / mL) [manufactured by Spectrum Laboratories] to remove unreacted monomers and surfactants. Remove the counteranion from the precipitate after dialysis using a strongly basic ion exchange resin to obtain amine-containing gel particles. Similar experiments were also conducted on materials without performing dialysis or ion exchange, and it was confirmed that they had almost the same functions. The particle size of the obtained amine-containing gel particles was 800 nm.

[0068] (Synthesis Example 2) Using N-isopropylacrylamide instead of N-tert-butylacrylamide, amine-containing gel particles were obtained in the same manner as in Synthesis Example 1, except that the composition of the three monomers was changed to 5 mol% of N-(dimethylaminopropyl)methacrylamide, 93 mol% of N-isopropylacrylamide, and 2 mol% of N,N'-methylenebisacrylamide. The hydrodynamic particle diameter of the obtained amine-containing gel particles in a 30°C aqueous dispersion was about 200 nm under a nitrogen atmosphere and about 400 nm in the presence of 10% CO2.

[0069] (Synthesis Example 3) Amine-containing gel particles were obtained in the same manner as in Synthesis Example 2, except that the concentration of the surfactant was changed to 0.16 mM. The hydrodynamic particle diameter of the obtained amine-containing gel particles in a 30°C aqueous dispersion was 600 nm.

[0070] (Synthesis Example 4) The composition of the three types of monomers was changed such that N-[(3-dimethylamino)propyl]methacrylamide was 5 mol%, N-isopropylacrylamide was 93 mol%, and N,N'-methylenebisacrylamide was 2 mol%, and a monomer solution was obtained in the same manner as in Synthesis Example 2 except that the total monomer concentration was 1040 mM. After nitrogen gas was passed through 2.4 mL of this solution for 10 minutes, an aqueous solution of the initiator 2,2'-azobis(2-methylpropionamidine)dihydrochloride was mixed and introduced onto the bottom surface of a stainless steel reactor for carbon dioxide absorption. A silicon rubber spacer (thickness: 100 μm) and mold in the shape of a frame were placed in the reactor, and a glass plate was placed on top of the spacer so as to sandwich the monomer solution, such that the monomer solution formed a liquid film with a thickness of 100 μm. In this state, the mixture was heated to 70°C and subjected to a polymerization reaction for 2 hours. After 2 hours, when the glass plate and spacer were removed, a hydrogel film in which amine-containing gel particles were crosslinked was obtained adhered to the bottom surface of the stainless steel reactor. When the primary diameter of the gel particles in the obtained hydrogel film was observed with a scanning electron microscope after drying the film, it was confirmed that the primary particle diameter of the particles was several tens to several micrometers and that a crosslinked structure was formed between the particles.

[0071] [II] Synthesis of stabilizer A polymer compound having an amino group as a stabilizer was synthesized as follows.

[0072] (Synthesis Example 5) Synthesis of polyvinylamine 5.0 g of N-vinylformamide (NVF) purified by distillation was added to 44 mL of pure water, and nitrogen was bubbled for 30 minutes while stirring in an oil bath at 60 °C. Then, 1.0 mL of an aqueous solution (19 mg / mL) of the initiator 2,2'-azobis[2-(2-imidazolin-2-yl)propane] dihydrochloride (VA-044) [manufactured by Wako Pure Chemical Industries, Ltd.] was added to this solution, and the reaction was carried out for 24 hours under a nitrogen atmosphere. Acetone was added to the solution after the reaction to precipitate the polymer, and the supernatant was removed. The obtained precipitate was dissolved in a solvent obtained by mixing pure water and ethanol at a volume ratio of 3:1. Furthermore, the operations of precipitating the polymer with acetone, removing the supernatant, and dissolving in an aqueous solvent were repeated several times to remove unreacted monomers. The solution of the obtained precipitate was concentrated under reduced pressure with an evaporator and then vacuum-dried to obtain solid poly(NVF). The dried solid was dissolved in a 2N aqueous sodium hydroxide solution so that the polymer concentration became 2 mass%, and a transparent and viscous liquid was obtained by stirring in an oil bath at 80 °C for 24 hours. Hydrochloric acid was added to this liquid to form a hydrochloride, and excess hydrochloric acid was removed with an evaporator. The liquid was dialyzed for 3 days using a dialysis membrane (MWCO 12 - 14,000, width: 75 mm, vol / length: 18 mL / mL) [manufactured by Spectrum Laboratories], and the amount of solution inside the dialysis membrane was measured. Then, the whole amount was freeze-dried to obtain poly(vinylamine) hydrochloride (PVAm·HCl). The progress of the reaction at each stage was 1 confirmed by 1H NMR (D2O). The counter anion was removed from this PVAm·HCl with a strongly basic ion exchange resin to obtain polyvinylamine.

[0073] (Synthesis Example 6) Synthesis of Hydrophobized Polyvinylamine In order to impart temperature responsiveness to the PVAm·HCl synthesized in Synthesis Example 5, a carboxylic acid having a bulky hydrophobic moiety was condensed. As the carboxylic acids, two types were used: isobutyric acid [manufactured by Sigma-Aldrich] having an isopropyl group or a tert-butyl group, respectively, and pivalic acid [manufactured by Wako Pure Chemical Industries, Ltd.]. The product obtained by condensing isobutyric acid is denoted as Isobutyl PVAm, and the product obtained by condensing pivalic acid is denoted as PivalPVAm. Specifically, hydrophobized polyvinylamine was obtained through the following steps. 100 mg (1.25 mmol-amine) of PVAm·HCl was dissolved in 20 mL of MilliQ water. Triethylamine (TEA) and isobutyric acid or pivalic acid were added to this aqueous solution. At this time, since pivalic acid is a solid at room temperature, it was dissolved in 100 L of methanol and added. After stirring for 10 minutes, the condensing agent 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride (EDC) [TCI] or 4-(4,6-dimethoxy-1,3,5-triazin-2-yl)-4-methylmorpholinium Chloride n-Hydrate (DMT-MM) [manufactured by Wako Pure Chemical Industries, Ltd.] was added, and the mixture was stirred for 6 hours. After completion of the reaction, the reaction solution was dialyzed for 3 days using a dialysis membrane (MWCO 12-14,000, width: 45 mL, vol / length: 6.42 mL / cm) [manufactured by Thermo Fisher Scientific]. The condensation rate was 1 calculated by HNMR (D2O). The counter anion was removed from the reaction solution after dialysis using a strongly basic ion exchange resin to obtain hydrophobized polyvinylamine.

[0074] [Evaluation of Gas Absorption Materials] Here, the amine-containing gel particles synthesized in Synthesis Examples 2 to 4 were used as the gel particles. (1) Examination of the Phase Transition of Amine-Containing Gel Particles The amine-containing gel particles synthesized in Synthesis Example 2 were dissolved in water to prepare a particle solution (4 mg / mL). The results of examining the temperature-dependent particle size change of amine-containing gel particles by heating the particle solution under conditions where carbon dioxide is present or absent are shown in Fig. 4. Fig. 5 shows the change in the solution pH when carbon dioxide was absorbed into the particle solution at 20°C, heated to around 60°C to dissipate carbon dioxide, and then the particle solution was cooled back to 20°C. Fig. 6 shows the results of titration tests performed on the particle solution held at 30°C, 45°C, 60°C, and 75°C with hydrochloric acid. Fig. 7 shows the change over time in the amount of carbon dioxide dissipated when carbon dioxide gas was absorbed into the particle solution at 30°C and then heated to around 75°C to dissipate carbon dioxide. Here, when measuring Figs. 5 and 7, the absorption of carbon dioxide gas into the particle solution was carried out by immersing a stainless steel reactor into which the particle solution was injected into a water bath at 20°C or 30°C and passing a mixed gas of carbon dioxide gas and nitrogen gas (10:90) through the container for 240 minutes. The dissipation of carbon dioxide gas was carried out by immersing this stainless steel reactor into a water bath at 60°C or 75°C. Also, the amount of carbon dioxide dissipated was determined by measuring the increase or decrease in the amount of carbon dioxide in the gas passing through the reactor during the dissipation process. Fig. 7 also shows the results of examining the amount of carbon dioxide gas dissipated under the same conditions for the homopolymers of N-[(3-dimethylamino)propyl]methacrylamide (low molecular weight amine) and N-(dimethylaminopropyl)acrylamide.

[0075] As shown in FIGS. 4 and 5, the particle size and pH of these amine-containing gel particles change depending on the temperature. Also, from FIG. 6, the apparent pKa of this particle solution was about 8 at 30° C. and about 5.5 at 75° C. From these facts, it was confirmed that these amine-containing gel particles are temperature-responsive particles that undergo a phase transition in response to a temperature change. Further, from FIG. 7, it was confirmed that these amine-containing gel particles efficiently dissipate the absorbed carbon dioxide gas by heating to 75° C. In addition, in an aqueous solution of a low molecular weight amine having a similar structure or a homopolymer of N-(dithylaminopropyl)acrylamide that does not form particles, hardly any dissipation of carbon dioxide was observed. Therefore, it was suggested that in the amine-containing gel particles, the phase transition of the particles triggered the efficient dissipation of carbon dioxide.

[0076] (2) Comparison of Gas Absorption and Dissipation Characteristics between Gel Particle Membranes and Gel Homogeneous Membranes (Example 1) The aqueous solution of amine-containing gel particles obtained in Synthesis Examples 2 to 4 was dried by freeze-drying to prepare a methanol solution (10 mg / mL). This methanol solution was poured into a stainless steel container, dried at 80° C., and then various gel particle membranes with different thicknesses were prepared by adding water and swelling. The thickness of the gel particle membrane was adjusted by changing the amount of the methanol solution poured into the container.

[0077] (Comparative Example 1) An ethanol solution of a monomer having the same composition as that prepared in Synthesis Example 2 was poured into a stainless steel container, degassed under a nitrogen atmosphere for 30 minutes, and then a DMF solution of benzoyl peroxide was added. A polymer membrane was prepared by reacting at room temperature for 6 hours or more under a nitrogen atmosphere. After washing this polymer membrane with water and drying at 80° C., various gel homogeneous membranes with different thicknesses were obtained by injecting water and swelling. The thickness of the gel homogeneous membrane was adjusted by changing the amount of the monomer solution poured into the container. Here, the "gel homogeneous membrane" refers to a dense film-like membrane that does not contain particles.

[0078] The reactor in which the gel particle film was formed in Example 1 and the reactor in which the gel homogeneous film was formed in Comparative Example 1 were immersed in a water bath at 30°C. A mixed gas of carbon dioxide gas and nitrogen gas (10:90), which was humidified with a humidifier at 60°C, was introduced into these containers at a rate of 300 mL / min for about 10 minutes. After confirming that the absorption of carbon dioxide into the film had ended with an infrared carbon dioxide concentration meter, the containers were transferred to a water bath at 75°C and held for 3 minutes. During this period, the amount of carbon dioxide in the gas passing through the containers was quantified with an infrared carbon dioxide concentration meter, and the dissipation rate and absorption rate of carbon dioxide were calculated from the increase and decrease. Regarding the gel particle film of Example 1 and the gel homogeneous film of Comparative Example 1, the results of measuring the dissipation rate of carbon dioxide gas are shown in Figs. 8 and 9, and the results of measuring the absorption rate of carbon dioxide are shown in Fig. 10. The numerical values in "nm" shown in Figs. 8 to 10 are the particle diameters of the gel particles. "300 nm gel particle film" represents the film of the gel particles synthesized in Synthesis Example 2, "1 μm gel particle film" represents the film of the gel particles synthesized in Synthesis Example 3, and "crosslinked gel particle film" represents the film of the gel particles synthesized in Synthesis Example 4. As shown in Figs. 8 to 10, the absorption and dissipation amounts of carbon dioxide in any of the gel particle films are larger than those in the gel homogeneous film. It was confirmed that by making the polymer compound having an amino group into particles, the absorption and dissipation abilities of carbon dioxide are improved. The dissipation rate of carbon dioxide in the gel particle film is particularly improved compared to the absorption rate because the swelling of the gel particles is large in the carbon dioxide absorption process and the voids between the particles are small, while the gel particles shrink in the dissipation process and the voids contributing to gas diffusion are large.

[0079] [Evaluation of Gas Absorbent] In the evaluation of the gas absorbent, the amine-containing gel particles synthesized in Synthesis Example 1 were used as the gel particles. (3) Effect of Supporting Gel Particle Film on Various Thin Plates as Carriers As carriers, stainless steel thin plates with a thickness of 0.1 mm or 0.3 mm (thermal conductivity is about 16 W / (m·K)), iron thin plates with a thickness of 0.1 mm (thermal conductivity is about 80 W / (m·K)), and graphite sheets with a thickness of 0.1 mm (Panasonic, PGS graphite sheet EYGS182310, thermal conductivity is 600 - 800 W / (mK)) were prepared. A silicone rubber sheet with holes as a mold was adhered to these carriers. On the other hand, the amine-containing dry gel particles synthesized in Synthesis Example 1 were dissolved in methanol to prepare a particle solution (50 mg / 3 mL). This particle solution was applied into the mold of the above carrier, placed in an incubator at 40 °C, and dried under reduced pressure. The particle solution was similarly applied to the back surface of the carrier and dried in a dryer at 80 °C for 30 minutes to obtain a laminate composed of the carrier and the dry particle film. However, for the graphite sheet, since the silicone rubber sheet of the mold did not adhere, the silicone rubber sheet was fixed with clips and used. While heating on a hot plate at 80 °C, the particle solution was spread using a pen and supported on the carrier. Thereafter, similar to the other carriers, the carrier coated with the particle solution was dried in a dryer at 80 °C to obtain a laminate. After measuring the weight of the dried laminate and quantifying the weight of the supported amine-containing dry gel particles, 4 equivalents (4 mL / g) of water was added to gelate the amine-containing dry gel particles. Through the above steps, a gas absorber with a gel particle film supported on the carrier was obtained. The thickness of the gel particle film of each obtained gas absorber was 37 μm.

[0080] Next, a reactor shown in Fig. 11 was prepared. This reactor has a pair of acrylic plates 1, butyl rubber gaskets 2 respectively arranged on the opposing surfaces of the pair of acrylic plates 1, and a plurality of screws 4 for fixing the pair of acrylic plates 1 to each other, and is configured such that a gas absorber 3 is sandwiched between the pair of butyl rubber gaskets 2. In addition, a gas inlet 5 and a gas outlet 6 are provided on the upper acrylic plate 1 of this reactor, and the gas from a gas supply means (not shown) is supplied to the gas absorber 3 through the gas inlet 5 and then discharged to the outside through the gas outlet 6. In this experimental example, the gas absorber was fixed to the reactor shown in Fig. 11, and an absorption and desorption experiment of carbon dioxide was carried out by flowing a carbon dioxide-containing gas (10 mL / min). As the carbon dioxide-containing gas, a gas at 60 °C obtained by humidifying nitrogen gas containing 10% carbon dioxide with a humidifier at 60 °C was used. The absorption of carbon dioxide was carried out by placing the reactor in a water bath at 30 °C, and the desorption of carbon dioxide was carried out by placing the reactor in a water bath at 75 °C. The desorption amount and absorption amount of carbon dioxide of the gas absorber were calculated from the increase and decrease in the amount of carbon dioxide in the gas passing through the reactor. The time-dependent changes in the absorption amount and desorption amount of carbon dioxide in each gas absorber are shown in Figs. 12 and 13. In Figs. 12 and 13, "sus" represents the case where the carrier is a stainless steel thin plate, "Fe" represents the case where the carrier is an iron thin plate, and "C" represents the case where the carrier is a graphite sheet. In Fig. 12, the desorption amount of carbon dioxide was measured by placing the reactor in a water bath at 75 °C at 0 minutes and 75 minutes from the start of the experiment, and the absorption amount of carbon dioxide was measured by placing the reactor in a water bath at 30 °C at 25 minutes and 100 minutes from the start of the experiment. In Fig. 12, the desorption amount and absorption amount of the gas absorber at the time points of 0 minutes, 25 minutes, 75 minutes, and 100 minutes are graphed. In Fig. 13, the desorption amount was measured by placing the reactor in a water bath at 75 °C at 0 minutes, 75 minutes, and 140 minutes from the start of the experiment, and the absorption amount was measured by placing the reactor in a water bath at 30 °C at 30 minutes, 100 minutes, and 170 minutes from the start of the experiment. In Fig. 13, the desorption amount and absorption amount of the gas absorber at the time points of 0 minutes, 30 minutes, 75 minutes, 100 minutes, 140 minutes, and 170 minutes are graphed. The vertical axis of the graphs in Figs. 12 and 13 represents the desorption amount of carbon dioxide per mass of amine-containing dry gel particles of the gas absorber, and a negative desorption amount indicates that carbon dioxide is being absorbed.

[0081] When a stainless steel thin plate with a thickness of 0.1 mm (thermal conductivity: about 16 W / (m·K)) was used as a carrier, it took about 14 minutes to release 25 mL of carbon dioxide per 1 g of amine-containing dry gel particles, about 26 minutes to absorb 25 mL of carbon dioxide, and the maximum reversible carbon dioxide release / absorption amount per 1 g of amine-containing dry gel particles was 31 - 38 mL (Figs. 12 and 13). On the other hand, when the thickness of the stainless steel thin plate was changed to 0.3 mm, the release rate was accelerated by about 1.5 times and the absorption rate was accelerated by about 2 times compared to the case of the stainless steel thin plate with a thickness of 0.1 mm. It only took about 10 minutes to release 25 mL of carbon dioxide per 1 g of amine-containing dry gel particles and about 13 minutes to absorb 25 mL of carbon dioxide (Fig. 12). Similarly, the reversible carbon dioxide release / absorption amount per 1 g of amine-containing dry gel particles was improved to 42 - 48 mL (Fig. 12). On the other hand, when a thin plate of iron with a relatively high thermal conductivity (thermal conductivity: about 80 W / (m·K)) was used as a carrier, despite the same thickness of 0.1 mm of the thin plate, the release rate was accelerated by about 1.8 times and the absorption rate was accelerated by about 2.2 times. It only took about 8 minutes to release 25 mL of carbon dioxide per 1 g of amine-containing dry gel particles and about 12 minutes to absorb 25 mL of carbon dioxide. Similarly, the reversible carbon dioxide release / absorption amount per 1 g of amine-containing dry gel particles was 33 - 42 mL (Fig. 13). Further, when a graphite sheet with a thickness of 0.1 mm (Panasonic, PGS graphite sheet EYGS182310, thermal conductivity: 600 - 800 W / (mK)) was used, both the release rate and the absorption rate were accelerated by about 2.3 times compared to the case of the stainless steel thin plate with a thickness of 0.1 mm. It only took about 6 minutes to release 25 mL of carbon dioxide per 1 g of amine-containing dry gel particles and about 10 minutes to absorb 25 mL of carbon dioxide. Similarly, the reversible carbon dioxide release / absorption amount per 1 g of amine-containing dry gel particles was improved to 60 mL (Fig. 13). Similarly, when an aluminum thin plate with a thickness of 0.1 mm was used, the release rate was accelerated by about 1.8 times and the absorption rate was accelerated by about 1.5 times compared to the case of the stainless steel thin plate with a thickness of 0.1 mm.

[0082] (4) Effect of Supporting Amine-Containing Gel Particle Films in Various Amounts A graphite sheet with a thickness of 0.1 mm (Panasonic, PGS graphite sheet EYGS182310, thermal conductivity of 600 - 800 W / (mK)) was used as a carrier, and when the thickness of the supported amine-containing gel particle film was changed from 37 μm to 230 μm, the reversible carbon dioxide absorption per unit volume of the reactor improved from 208 mL / L to 1160 mL / L (Figure 14). In Figure 14, carbon dioxide was sufficiently absorbed at 30 °C to reach an equilibrium state, and then the temperature was raised to 75 °C to release carbon dioxide. Carbon dioxide was released with the start of release set as 0 minutes, and then the reactor was placed in a 30 °C water bath 30 minutes after the start of the experiment to measure the carbon dioxide absorption. Also, Figure 14 is a graph showing the release and absorption amounts of the gas absorber from the 0-minute and 30-minute time points. The vertical axis of the graph represents the carbon dioxide release amount per unit volume of the reactor. Negative absorption amounts indicate that carbon dioxide is being absorbed.

[0083] (5) Effect of Supporting an Accelerator-Containing Amine-Containing Gel Particle Film Using a graphite sheet with a thickness of 0.1 mm (Panasonic, PGS graphite sheet EYGS182310, thermal conductivity of 600 - 800 W / (mK)) as a carrier, a 230-μm amine-containing gel particle film was supported, and 1 M of N,N’,N”-pentamethyldiethylenetriamines was added as an accelerator. As a result, the reversible carbon dioxide absorption per unit volume of the reactor improved from 1160 mL / L to 4000 mL / L.

[0084] (6) Effect of Supporting a Gel Thin Film with Various Fibers as Carriers Figure 15 shows the stainless-steel reactor used in this experimental example. This reactor has a space part 11 with a volume of 60000 mm 3 (length 80 mm, width 150 mm, depth 5 mm), and 13 rectifying plates 12 are arranged in the space part 11 at 10-mm intervals. Also, this reactor is provided with a gas inlet 13 for introducing gas from a gas supply means (not shown) into the space part 11 and a gas outlet 14 for discharging the gas in the space part 11.

[0085] A quantitatively determined amount of amine-containing dry gel particles was dissolved in methanol and stirred overnight. The concentration of the solution was adjusted to be about 17 mg / mL. Next, as a carrier, a stainless-steel fiber felt cut into 80 mm × 8 mm × 5 mm (Nippon Seisen Co., Ltd., Naslon felt 12-5-1500 and 8-5-1500, fiber diameter 12 μm and 8 μm, thickness 5 mm, basis weight 1500 g / m 2) and an aluminum fiber felt (fiber diameter: 100 μm) were prepared. These carriers were fixed in the space part 11 of the reactor shown in Fig. 15 and placed on a hot plate at 80 °C for heating. A methanol solution of amine-containing dry gel particles was evenly applied to the heated carriers with a syringe. When the evaporation of methanol was slow due to heating from below, heat was applied from above using a dryer to evaporate the methanol so that the amine-containing dry gel particles could be uniformly supported. A predetermined amount of water was added to the amine-containing dry gel particles supported on the carrier to cause gelation, thereby obtaining an amine-containing gel-supported material (gas absorber). This gas absorber was installed inside the reactor of Fig. 15, and an absorption and desorption experiment of carbon dioxide was conducted by flowing a carbon dioxide-containing gas (10 mL / min). As the carbon dioxide-containing gas, nitrogen gas containing 10% carbon dioxide and humidified at 60 °C with a humidifier at 60 °C was used. The absorption of carbon dioxide was carried out by placing the reactor in a water bath at 30 °C, and the desorption of carbon dioxide was carried out by placing the reactor in a water bath at 75 °C. The gas passing through the reactor was passed through a condenser at 5 °C to remove the moisture in the gas, and the amount of carbon dioxide in the gas was quantified at regular intervals using gas chromatography (manufactured by Shimadzu Corporation, product name GC-TCD). From the increase and decrease of carbon dioxide in the gas, the desorption amount and absorption amount of carbon dioxide of the gas absorber were calculated. The time-dependent changes in the absorption amount and desorption amount of carbon dioxide in each gas absorber are shown in Figs. 16 to 23. Figs. 16 to 19 are graphs of the gas absorber in which the carrier is Nylon felt 12-5-1500. In Figs. 20 to 23, "AlΦ100" represents the one in which the carrier is an aluminum fiber felt, "susΦ12" or "12-5-1500" represents the one in which the carrier is Nylon felt 12-5-1500, and "8-5-1500" represents the one in which the carrier is Nylon felt 8-5-1500. Also, in Figs. 16 to 23, the numerical values with the unit of "mg / ml" represent the coating amount of the amine-containing dry gel particles on the carrier. In Figs. 16 to 23, the desorption amount of carbon dioxide was measured by placing the reactor in a water bath at 75 °C at 0 minutes, 71 minutes, and 142 minutes from the start of the experiment, and the absorption amount of carbon dioxide was measured by placing the reactor in a water bath at 30 °C at 25 minutes and 96 minutes from the start of the experiment. In Figs. 16 to 23, the desorption amount or absorption amount of the gas absorber at the time points of 0 minutes, 25 minutes, 71 minutes, 96 minutes, and 142 minutes is graphed.Of FIGS. 16 to 23, the vertical axis of the graphs in FIGS. 16, 18, 20, and 22 represents the amount of carbon dioxide emitted per unit volume of the fiber assembly, and the numerical values represented by the vertical axes of the other graphs are the same as those represented by the vertical axis of FIG. 12.

[0086] When fibers were used as the carrier, it was found that the thickness of the fibers and the amount of gel supported affected the reversible absorption amount and absorption rate. That is, when various amounts of amine-containing gel particles (water addition amount: 4 mL / g) were applied to a stainless steel fiber felt (Nippon Seisen Co., Ltd., Naslon felt 12-5-1500, fiber diameter: 12 μm, thickness: 5 mm, basis weight: 1500 g / m 2 ), when the application amount of the amine-containing dry gel particles was increased from 100 mg to 200 mg, the reversible carbon dioxide absorption amount improved by about two-fold. However, when the application amount was increased from 200 mg to 400 mg, the reversible carbon dioxide absorption amount decreased dramatically (FIGS. 16 and 17). Also, when the amount of water added was changed while keeping the amount of amine-containing dry gel particles constant, even when the amount of amine-containing dry gel particles was large, the reversible carbon dioxide absorption amount improved slightly when the water addition amount was reduced from 4 mL / g to 2 mL / g (FIGS. 18 and 19). From the above results, it was found that it is necessary to limit the filling rate of the gel including water to about 15 to 40% for efficient reversible absorption of carbon dioxide. When the fiber diameter was changed from 12 μm to 100 μm (aluminum fiber) at the optimized filling rate, the reversible carbon dioxide absorption performance decreased despite the high thermal conductivity of the material (aluminum) (FIGS. 20 and 21). This is presumably because the surface area of the fibers decreased and the thickness of the gel particle film increased as the fiber diameter increased. On the other hand, when the fiber diameter was changed from 12 μm to 8 μm, it was found that the emission / absorption behavior hardly changed (FIGS. 22 and 23). This indicates that when fibers thinner than 100 μm are used, the absorption / emission performance does not strongly depend on the fiber diameter and high performance can be achieved.

[0087] (7) Comparison of the results with and without supporting the gel particle film on the carrier (Preparation example and evaluation of the gel particle film not supported on the carrier) 2.4 g of amine-containing dry gel particles were dissolved in methanol and stirred overnight to obtain a methanol solution of amine-containing dry gel particles (particle solution). The above-mentioned stainless steel reactor (Figure 15) was placed on a hot plate at 80 °C and heated, and the prepared particle solution was applied to the inner surface of this reactor while evaporating methanol. Specifically, one-third of the total solution volume was applied to the lower part of the stainless steel reactor, one-third of the total solution volume was applied to the upper lid part, and one-third of the total solution was applied to the comb part of the lid. After drying the particle solution, 4.8 mL of water was added to gelate the membrane, and an amine-containing gel particle membrane was formed on the inner surface of the reactor. A carbon dioxide absorption and desorption experiment was carried out by flowing a carbon dioxide-containing gas (50 mL / min) through this reactor. As the carbon dioxide-containing gas, a gas at 60 °C humidified with a nitrogen gas containing 10% carbon dioxide in a humidifier at 60 °C was used. The absorption of carbon dioxide was carried out by placing the reactor in a water bath at 30 °C, and the desorption of carbon dioxide was carried out by placing the reactor in a water bath at 75 °C. The gas passing through the reactor was passed through a condenser at 5 °C to remove the moisture in the gas, and the amount of carbon dioxide in the gas was quantified at regular intervals by gas chromatography (manufactured by Shimadzu Corporation, trade name GC-TCD). The desorption amount and absorption amount of carbon dioxide of the gel particle membrane were calculated from the increase and decrease amount of carbon dioxide in the gas. The time-dependent changes in the absorption amount and desorption amount of carbon dioxide in the gel particle membrane are shown in Figure 24.

[0088] (Preparation example and evaluation of gel particle membrane supported on carrier) 2.4 g of amine-containing dry gel particles were dissolved in methanol and stirred overnight to obtain a methanol solution of amine-containing gel particles (particle solution). Inside the stainless steel reactor (Figure 15), a stainless steel fiber felt (Naslon felt, 12 - 5 - 1500 / m 2) Twelve of them were filled and the reactor was placed on a hot plate at 80 °C and heated. Using a syringe, the particle solution was evenly applied so that 200 mg of amine-containing dry gel particles were supported on each felt in the reactor, and the methanol in the particle solution was evaporated by leaving it in this state. When the evaporation of methanol was slow, heat was applied from above using a dryer to evaporate the methanol so that the amine-containing dry gel particles could be uniformly supported. To each of the twelve carriers on which the amine-containing dry gel particles were supported, 400 μL (4.8 mL in total) of water was added to gel the particles, and a gas absorber with an amine-containing gel particle film supported on the carrier was obtained. An absorption and desorption experiment of carbon dioxide was carried out by flowing a carbon dioxide-containing gas (50 mL / min) into the container in which the gas absorber was formed. As the carbon dioxide-containing gas, a gas at 60 °C humidified with a nitrogen gas containing 10% carbon dioxide in a humidifier at 60 °C was used. The absorption of carbon dioxide was carried out by placing the reactor in a water bath at 30 °C, and the desorption of carbon dioxide was carried out by placing the reactor in a water bath at 75 °C. The gas passing through the reactor was passed through a condenser at 5 °C to remove the moisture in the gas, and the amount of carbon dioxide in the gas was quantified at regular intervals by gas chromatography (manufactured by Shimadzu Corporation, product name GC-TCD). From the increase and decrease of carbon dioxide in the gas, the desorption amount and absorption amount of carbon dioxide of the gas absorber were calculated. The time-dependent changes in the absorption amount and desorption amount of carbon dioxide in each absorber are shown in Figure 24. In Figure 24, "12-5-1500 felt" represents a gas absorber using a stainless steel fiber felt (Naslon felt 12-5-1500) as a carrier, and the numerical value with the unit of "mg / ml" represents the coating amount of the amine-containing dry gel particles on the carrier or container. In Figure 24, the absorption amount of carbon dioxide was measured by placing the reactor in a water bath at 30 °C at 25 minutes, 96 minutes, and 167 minutes from the start of the initial desorption, and the desorption amount of carbon dioxide was measured by placing the reactor in a water bath at 75 °C at 0 minutes, 71 minutes, and 142 minutes from the start of the experiment. In Figure 24, the desorption amount or absorption amount of the gas absorber at the time points of 0 minutes, 25 minutes, 71 minutes, 96 minutes, 142 minutes, and 167 minutes is graphed. The numerical value represented by the vertical axis in the graph in Figure 24 is the same as the numerical value represented by the vertical axis in Figure 12.

[0089] As a result of the above experiments, in the gel particle film directly formed inside the reactor, only 50 to 120 mL of carbon dioxide could be reversibly absorbed. However, in the gas absorber in which a felt made of stainless steel fibers with a fiber diameter of 12 μm was filled inside the same reactor to support the gel particle film, 98 to 130 mL of carbon dioxide could be reversibly absorbed. Also, when the gel particle film was directly formed in the reactor, it took 23 minutes to dissipate 120 mL of carbon dioxide gas in the above reversible absorption process. In contrast, when the gel particle film was supported on the stainless steel fiber felt, the dissipation of carbon dioxide gas could be completed within 9 minutes. Similarly, in the gel particle film directly formed inside the reactor, it took 45 minutes to absorb about 120 mL of carbon dioxide gas in the above reversible absorption process. In contrast, when the gel-like film was supported using the stainless steel fiber felt as a carrier, 120 mL of carbon dioxide gas could be absorbed within 18 minutes. As described above, it was confirmed that by using metal fibers as a carrier and supporting the gel particle film at an appropriate filling rate, the average reversible absorption amount can be improved by 1.3 times, the dissipation rate by 2.6 times, and the absorption rate by 2.5 times.

[0090] Next, experiments were conducted using a felt made of stainless steel fibers and a sintered metal fiber obtained by sintering a felt made of stainless steel fibers, respectively. On an iron plate heated to 80 °C, a felt made of stainless steel fibers (naslon felt, 12 - 5 - 1500 / m 2 ) or a sintered metal fiber obtained by sintering a felt made of stainless steel fibers (manufactured by Nippon Seisen Co., Ltd., SUS316L, basis weight 1600 g / m 2, a fiber diameter of 50 μm and a porosity of 89%) was placed, and 550 μL of a solution prepared by dissolving the amine-containing gel particles obtained in Synthesis Example 1 in methanol to a concentration of 20 mg / mL was added and dried. Then, it was set in a reactor, and 4 equivalents of water was added to the amine-containing gel particles. In each experiment, three samples with different gel particle filling rates were prepared, and the amounts of carbon dioxide released and absorbed were measured for them by the same method as above. Figure 25 is a graph showing the relationship between the gel filling rate and the amounts of carbon dioxide released and absorbed. From Figure 25, it was confirmed that when sintered metal fibers were used, even when the gel particle filling rate was high (for example, 60% or more), the high carbon dioxide absorption and release ability of the gel particles could be maintained. Next, a sintered metal fiber (fiber diameters 12 μm and 50 μm) obtained by sintering a felt made of stainless steel fibers, a foamed metal (manufactured by Sumitomo Metal, Cermet #4, #5, #7), and a sintered nickel fiber (fiber diameter 40 μm) were each used to conduct a carbon dioxide absorption and release experiment in the same manner as above. In Figure 26, the reactor was placed in a water bath at 30 °C at 25 minutes and 96 minutes from the start of the first release to measure the amount of carbon dioxide absorbed, and placed in a water bath at 75 °C at 0 minutes and 71 minutes from the start of the experiment to measure the amount of carbon dioxide released. In Figure 26, the amounts of carbon dioxide released or absorbed by the gas absorber at the time points of 0 minutes, 25 minutes, 71 minutes, and 96 minutes are graphed. The numerical value represented by the vertical axis in the graph in Figure 26 is the same as the numerical value represented by the vertical axis in Figure 12. Figure 26 shows that the foamed metal can be used equivalently to the sintered metal fiber. Also, it was confirmed that the sintered nickel fiber is excellent in terms of the carbon dioxide absorption rate, absorption amount, release amount, and release rate, and can be preferably adopted.

[0091] When 2.4 grams of amine-containing dry gel particles were dissolved in methanol, uniformly coated inside the reactor of Figure 15, and dried, and then 4.8 mL of water was added to form a gel particle film, only 50 to 120 mL of carbon dioxide could be reversibly absorbed, but a volume of approximately 60000 mm of almost the same size 3Four graphite sheets (Panasonic, PGS graphite sheet EYGS182310, thickness 0.1 mm, thermal conductivity 600 - 800 W / (mK)) with a thickness of 0.1 mm are stacked inside a space 2 (40 mm long, 170 mm wide)) and 2.4 grams of gel particles are uniformly applied to both sides of each plate (6800 mm 2 (40 mm long, 170 mm wide)), and when 4.8 mL of water is added to support the gel film, 120 - 140 mL of carbon dioxide can be reversibly absorbed. Also, when the gel particle film was directly formed inside the reactor, in the above reversible absorption process, it took 23 minutes to dissipate 120 mL of carbon dioxide gas, while when four graphite sheets supporting the gel film were stacked, the dissipation of carbon dioxide gas could be completed within 15 minutes. Similarly, when the gel particle film was directly formed inside the reactor, in the above reversible absorption process, it took 45 minutes to dissipate about 20 mL of carbon dioxide gas, while when four graphite sheets supporting the gel film were stacked, the dissipation of carbon dioxide gas could be completed within 25 minutes. As described above, by supporting the gel particle film on the graphite sheet as the carrier, the average reversible absorption amount could be increased by 1.5 times, the dissipation rate by 1.5 times, and the absorption rate by 1.8 times. Also, when 2.4 grams of amine-containing dry gel particles were dissolved in methanol, uniformly applied, and dried inside the reactor shown in Fig. 15, and then 4.8 mL of water was added to create a gel particle film, only 50 - 120 mL of carbon dioxide could be reversibly absorbed. However, for a plate-type heat exchanger 3 (6 stainless steel thin plates (each 18000 mm with a length of 40 mm, a width of 170 mm, and a depth of about 8.8 mm), manufactured by Nisaka Seisakusho Co., Ltd., UX - 0005A - J - 8 - sheet formation) 2) When 2.4 grams of amine-containing dry gel particles were dissolved in methanol, uniformly coated, dried, and then 4.8 mL of water was added to support the gel particle film, 120 to 140 mL of carbon dioxide could be reversibly absorbed. Also, when the gel particle film was directly formed inside the reactor, in the above reversible absorption process, it took 23 minutes to dissipate 120 mL of carbon dioxide gas. In contrast, when four stainless steel thin plates carrying the gel film were stacked, the dissipation of carbon dioxide gas could be completed within 14 minutes. Similarly, when the gel particle film was directly formed inside the reactor, in the above reversible absorption process, it took 45 minutes to dissipate approximately 120 mL of carbon dioxide gas. In contrast, when four stainless steel thin plates carrying the gel film were stacked, the dissipation of carbon dioxide gas could be completed within 24 minutes. As described above, by supporting the gel particle film on the stainless steel thin plate as the carrier, the average reversible absorption amount could be increased by 1.5 times, the dissipation rate by 1.6 times, and the absorption rate by 1.9 times.

[0092] Also, regarding the heat transfer surfaces (each 18000 mm 2 ) of six stainless steel thin plates of a plate-type heat exchanger (Hisaka Works, Ltd., UX-0005A-J-8 sheets woven), when 3.9 grams of the amine-containing dry gel particles obtained in Synthesis Example 1 were dissolved in methanol, uniformly coated, dried, and then 4.8 mL of water was added to support the gel particle film, nitrogen gas containing 10.9% CO2 was passed at 200 mL / min to perform the dissipation and absorption of carbon dioxide. The reactor was placed in a 30°C water bath at 25 minutes, 96 minutes, and 167 minutes from the start of the initial dissipation to measure the carbon dioxide absorption amount, and placed in a 75°C water bath at 0 minutes, 71 minutes, and 142 minutes from the start of the experiment to measure the carbon dioxide dissipation amount. In Figure 27, the dissipation amount or absorption amount of the gas absorber at the time points of 0 minutes, 25 minutes, 71 minutes, 96 minutes, 142 minutes, and 167 minutes is graphed. The numerical value represented by the vertical axis of the graph in Figure 27 is the same as the numerical value represented by the vertical axis of Figure 12. Very good results were obtained for the carbon dioxide absorption rate, absorption amount, dissipation amount, and dissipation rate. Figure 28 shows the change in vapor pressure when the temperature of the water tank was changed between 30 and 75 °C. The results in Figure 28 indicate that the gel particle film reversibly absorbs water vapor as well as carbon dioxide.

[0093] (8) Examination of the method for stabilizing the gel-like film A gel particle film composed only of amine-containing gel particles has high water absorbency, and depending on the repeated use conditions, an increase in film thickness may occur, which may lead to a decrease in gas absorption / dissipation rate and reversible absorption amount due to the blockage of the gas flow path. Furthermore, the gel particle film may fluidize and flow out from the carrier surface. To solve these problems, a stabilizer was added to the gel particle film, and the conditions for obtaining a stable film even under conditions of a large amount of water addition were examined.

[0094] (8-1) Stabilization of an amine-containing gel particle film using a polyvinyl alcohol / polyethylene copolymer as a stabilizer A polyvinyl alcohol / polyethylene copolymer as a stabilizer was added to an amine-containing gel particle film composed of amine-containing gel particles so as to be 33% by mass or 50% by mass (mass fraction of solids excluding the dispersion medium), and the behavior of the gel particles when an excessive amount of water was added was observed. Specifically, the following experiment was conducted. First, a particle solution in which amine-containing dry gel particles labeled with a fluorescent dye (dansyl group), unlabeled amine-containing dry gel particles, and a polyvinyl alcohol / polyethylene copolymer as a stabilizer were dissolved in a solvent was prepared with an application amount of dry gel particles of 113 mg / m 2It was applied into the glass vial so as to obtain the [required state], and dried in an oven at 80 °C for 1.5 hours to form a gel particle film. The polyvinyl alcohol / polyethylene copolymer used was EVOH (E29) (manufactured by Nippon Gohsei Chemical Industry Co., Ltd., polyethylene copolymerization ratio: 29%) or EVOH (E44) (manufactured by Nippon Gohsei Chemical Industry Co., Ltd., polyethylene copolymerization ratio: 44%). Also, a gel particle film was formed in the glass vial in the same manner except that no stabilizer was used. An excessive amount (10 mL / 20 mg polymer) of water was injected into each glass vial and left for 48 hours, and then the amount of amine-containing gel particles eluted from the gel particle film into the aqueous layer was calculated from the amount of the fluorescent dye. As a result, the amine-containing gel particle film without the added stabilizer completely dissolved, and strong fluorescence above the detection limit was observed. When the polyvinyl alcohol / polyethylene copolymer (EVOH (E29)) with a polyethylene copolymerization ratio of 29% was used as the stabilizer, the elution amount of the amine-containing gel particle film could be suppressed to less than half of that without addition by adding 33% by mass. The gel particle film with 50% by mass of the stabilizer had almost completely suppressed elution, and the amount of the fluorescent dye-labeled amine-containing gel particles eluted into water was below the detection limit. On the other hand, it was found that for the stabilizer (EVOH (E44)) with a polyethylene polymerization ratio of 44%, the amount of the fluorescent dye eluted into the aqueous layer could be suppressed below the detection limit by adding 33% by mass or 50% by mass. From the above, it was found that adding a polymer with a high polyethylene content and high crystallinity as a stabilizer is effective for suppressing the elution of amine-containing gel particles at room temperature. Furthermore, the carbon dioxide absorption amount and emission amount of the gel particle film prepared under the same conditions were determined using the reactor of Fig. 15. The change over time in the carbon dioxide emission amount of the gel particle film is shown in Fig. 29, and the change over time in the carbon dioxide absorption amount of the gel particle film is shown in Fig. 30. In Figs. 29 and 30, the vertical axis represents the carbon dioxide emission amount or absorption amount per unit mass of the amine-containing dry gel particles. As shown in Figs. 29 and 30, both the carbon dioxide absorption amount and emission amount of the gel particle film with the added stabilizer were equivalent to those of the gel particle film without the added stabilizer. However, regarding the absorption rate, there was a tendency for it to become slightly slower as the addition amount of the stabilizer increased.

[0095] As described above, it was confirmed that the addition of the polyvinyl alcohol / polyethylene copolymer dramatically suppresses the elution of amine-containing gel particles at room temperature. However, when the temperature was repeatedly changed between 75°C and 30°C in an environment where water is present, and the dissipation / absorption of carbon dioxide was repeated, the stability of the membrane decreased depending on the conditions, and the gel particle membrane sometimes fragmented. Therefore, a method for preparing a gel particle membrane that can more stably maintain its form even in an environment where the temperature and the amount of carbon dioxide absorption change greatly was investigated. A predetermined amount of stabilizer (EVOH (E44)) and amine-containing dry gel particles were dissolved in a mixed solvent of isopropanol and water (mixed volume ratio 6 to 4) and applied to a glass vial, followed by stirring at 60 °C for 4 hours. To this particle solution containing the stabilizer, a titanium crosslinking agent (TC-310 or TC-400 manufactured by Matsumoto Fine Chemical Co., Ltd.) diluted with the same solvent was added such that the mass ratio was about one-eighth of the stabilizer (EVOH (E44)). After stirring for 1 hour, the mixture was dried in a hot air dryer at 60 °C for 12 hours to form a particle film. Thereafter, heat treatment was performed at 110 °C or 150 °C for 1 hour to stabilize the particle film. 200 equivalents of water were added to this particle film to cause gelation, and the mixture was allowed to stand at room temperature for 12 hours. As a result, in the gel particle film that gelled after heat treatment at 110 °C, some stabilization of the film was observed due to the addition of a stabilizer of 9 mass% or more (mass fraction of solid excluding the dispersion medium), but the behavior of the film fragmenting and peeling off from the glass vial was observed (Fig. 31(A)). On the other hand, the gel particle film that gelled after heat treatment at 150 °C did not break even after standing at room temperature for 12 hours, and it was confirmed that sufficient stabilization was achieved by the addition of a stabilizer of 3 mass% (mass fraction of solid excluding the dispersion medium). Also, the phenomenon of the gel particle film dissolving was almost completely suppressed (Fig. 31(B)). Furthermore, when the temperature was repeatedly changed between 75 °C and 30 °C in the presence of 10% carbon dioxide, for the gel particle film formed with a crosslinked structure using the titanium crosslinking agent (TC-400), due to the addition of stabilizers of 6 mass% and 33 mass% (mass fraction of solid excluding the dispersion medium), and for the gel particle film to which the titanium crosslinking agent (TC-310) was added, due to the addition of a stabilizer of 6 mass% (mass fraction of solid excluding the dispersion medium), swelling of the film was observed, but fragmentation and breakage of the film were not observed (Fig. 31(C)). For the gel particle film formed with a crosslinked structure using TC-310 and added with a stabilizer of 33 mass% (mass fraction of solid excluding the dispersion medium), no significant change in the degree of swelling was observed even after performing 2 cycles of temperature change.Furthermore, regarding the gel particle film in which a cross-linked structure was formed with TC-310 and a stabilizer of 33 mass% (mass fraction of solid excluding the dispersion medium) was added, when the reversible carbon dioxide absorption performance was evaluated using the reactor of Fig. 15, it was confirmed that although the absorption amount and the dissipation amount of carbon dioxide decreased by about 10% compared to the gel particle film without the stabilizer, there was almost no adverse effect on the dissipation rate and the absorption rate (Fig. 32). In Fig. 32, "EVOH & TC-310" represents the one in which a cross-linked structure was formed with TC-310 and the stabilizer EVOH (E44) was added, and "no addition" represents the one in which a cross-linked structure was formed with TC-310 and the stabilizer EVOH (E44) was not added. In Fig. 32, the carbon dioxide absorption amount was measured by putting the reactor into a water tank at 30°C at 14 minutes and 74 minutes from the start of the experiment, and the carbon dioxide dissipation amount was measured by putting it into a water tank at 75°C at 0 minute and 60 minutes from the start of the experiment. In Fig. 32, the dissipation and absorption amounts of the gas absorber at the time points of 0 minute, 14 minutes, 60 minutes, and 74 are graphed. The numerical value represented by the vertical axis of the graph in Fig. 32 is the same as the numerical value represented by the vertical axis of Fig. 12.

[0096] (8-2) Stabilization of Gel Particle Film with Polyvinylamine as Stabilizer In addition to polyvinyl alcohol / polyethylene copolymer, polyvinylamine was investigated as a stabilizer for the gel particle film. An aqueous solution in which amine-containing gel particles were dissolved and an aqueous polyvinylamine solution were mixed at various mass ratios, stirred for 3 days, then applied to a glass vial and dried under reduced pressure at 40 °C, and then dried at normal pressure at 80 °C for 1 hour. As a result, an amine-containing dry gel particle film was formed inside the glass vial. 4 equivalents of water was added to this amine-containing dry gel particle film to form a gel particle film, and a gas containing 10% carbon dioxide was passed through at room temperature for 3 hours to dissolve carbon dioxide. Next, the temperature of the gel particle film was raised to 75 °C and allowed to stand for 12 hours in the presence of a 10% carbon dioxide-containing gas. As a result, the primary amines of polyvinylamine were crosslinked with carbon dioxide, and whether the film was stabilized was examined. 200 masses of water was injected into the glass vial, allowed to stand for 1 hour, and then the stability of the film was observed. As a result, it was found that the gel particle film to which 9 mass% or more of polyvinylamine (mass fraction of solid excluding the dispersion medium) was added was relatively stable. When the temperature was raised to 75 °C and allowed to stand for 12 hours in the presence of a 10% carbon dioxide-containing gas was replaced by allowing to stand for 12 hours in the presence of a 10% carbon dioxide-containing gas at room temperature, the stability of the film did not improve. From this, it was suggested that the carbon dioxide dissolved in the film caused a crosslinking reaction at 75 °C, stabilizing the film.

[0097] (8-3) Stabilization of a Gel Particle Thin Film Using a Polymerizable Compound as a Stabilizer The stabilization of a gel particle film by employing a polymerizable compound as a stabilizer of the gel particle film and polymerizing it in the presence of a polymerization initiator was investigated. 100 mg of the amine-containing gel particles obtained in Synthesis Example 1 was dissolved in 6 mL of methanol. Further, 95 parts by mass of N,N-dimethylaminopropylmethacrylamide (DMAPM) and 5 parts by mass of N,N'-methylenebisacrylamide (BIS) were dissolved in methanol to prepare a methanol solution with a concentration of 0.05 mg / mL. Furthermore, a methanol solution of a polymerization initiator (IRGACURE184) was also prepared, and these three kinds of methanol solutions were mixed. The mixing ratio was such that the total amount of DMAPM and BIS was 56 parts by mass with respect to 100 parts by mass of the amine-containing gel particles. Also, the polymerization initiator was mixed in an amount such that it was 1 / 60 mol with respect to the monomer. This mixed solution was cast into a stainless steel reactor and slowly dried at room temperature, and then dried in a constant temperature bath at 35°C. Thereafter, it was irradiated with ultraviolet rays for polymerization. Further, water was added to obtain a gel particle film having a uniform film shape. In this production method, even when a large amount of water was added, a gel particle film having a substantially uniform film shape was obtained only by partial swelling. In the same manner as above, an experiment on the absorption and desorption of carbon dioxide was conducted. In FIG. 33, from the start of desorption at the first time, at 25 minutes, 96 minutes, and 167 minutes, the reactor was placed in a water bath at 30°C to measure the absorption amount of carbon dioxide, and at 0 minutes, 71 minutes, and 142 minutes from the start of the experiment, it was placed in a water bath at 75°C to measure the desorption amount of carbon dioxide. In FIG. 33, the desorption amount or absorption amount of the gas absorber at the time points of 0 minutes, 25 minutes, 71 minutes, 96 minutes, 142 minutes, and 167 minutes is graphed. The numerical value represented by the vertical axis of the graph in FIG. 33 is the same as the numerical value represented by the vertical axis of FIG. 12. FIG. 33 shows that the obtained gel particle film achieves extremely high absorption rate, absorption amount, desorption amount, and desorption rate. The gel particle film after measurement was not overly swollen and was stable. In the above experiment, as the polymerizable compound, instead of DMAPM:BIS = 95:5, a mixture of DMAPM:BIS:NIPAM = 55:5:45 was used, and a gel-like film was prepared in the same manner, and a test on the absorption and desorption of carbon dioxide was conducted to confirm the film state. Here, NIPAM is N-isopropylacrylamide. The results of graphing the desorption amount or absorption amount of the gas absorber are shown in FIG. 34. As shown in FIG. 34, good absorption rate, absorption amount, desorption amount, and desorption rate were achieved. Even when a large amount of water was added when forming the gel-like film, the film maintained a uniform state.Moreover, even after the gas absorption and desorption test, the gel particle film was not overly swollen and was stable. Also, in the above experiment, as a polymerizable compound, instead of DMAPM:BIS = 95:5, a mixture of DMAPM:BIS:NIPAM = 30:5:65 was used to prepare a gel-like film in the same manner, and the absorption and desorption tests of carbon dioxide were conducted to confirm the film state. The results of graphing the desorption amount or absorption amount of the gas absorber are shown in FIG. 35. As shown in FIG. 35, good absorption rate, absorption amount, desorption amount, and desorption rate were achieved. Even when a large amount of water was added during the formation of the gel-like film, the film maintained a uniform state. Moreover, even after the gas absorption and desorption test, the gel particle film was not overly swollen and was stable. Furthermore, in the above experiment, without changing the point of using DMAPM:BIS = 95:5 as the polymerizable compound, the solvent was changed from methanol to water, and the polymerization initiator was changed to 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylpropiophenone, and a gel-like film was prepared in the same manner, and the absorption and desorption tests of carbon dioxide were conducted to confirm the film state. The results of graphing the desorption amount or absorption amount of the gas absorber are shown in FIG. 36. As shown in FIG. 36, good absorption amount and desorption amount were achieved, but the absorption rate and desorption rate were slightly slow. Even when a large amount of water was added during the formation of the gel-like film, the film maintained a uniform state. Moreover, even after the gas absorption and desorption test, the gel particle film was not overly swollen and was stable.

[0098] (9) Effect of adding absorption and desorption promoter Various low-molecular compounds were added to the gel particle film as absorption and desorption promoters, and the improvement effects on the absorption amount, absorption rate, desorption amount, and desorption rate of carbon dioxide for the gel-like film were examined. A gel particle film was formed in the reactor shown in Fig. 15, and a low-molecular compound represented by the following formula was added to the gel particle film, or amine-containing dry gel particles were introduced into the reactor, and water, PMDETA containing almost no water, or an aqueous solution of PMDETA was added. Then, carbon dioxide absorption and desorption were carried out for one cycle under the same conditions as those used in the measurement of Fig. 16, and the changes over time in the carbon dioxide absorption amount and desorption amount were examined. The results are shown in Figs. 37 to 42. In Figs. 37 to 40, "GP + H2O" represents a gel particle film containing no low-molecular compound represented by the following formula, and the others represent gel particle films to which the low-molecular compounds shown in the table were added at a concentration of 3N or 13% by mass in terms of amine concentration. In Figs. 41 to 42, "GP + H2O" represents adding water to amine-containing dry gel particles, "GP + PMDEA" represents adding PMDETA containing almost no water to amine-containing dry gel particles, and the others represent adding PMDETA aqueous solutions with amine-equivalent concentrations of 1N, 3N, and 10N to amine-containing dry gel particles. From Figs. 37 to 42, it was confirmed that in the gel particle films added with amine compounds, particularly Imino-bis(N,N-dimethylpropylamine) (IBDPA) and N,N’,N”-pentamethyldiethylenetriamine (PMDETA), the absorption rate, absorption amount, desorption amount, and desorption rate were remarkably improved. At that time, when the concentration of the amine compound was too high, the amount of water relative to the amine was too much, and conversely, the absorption amount tended to decrease, suggesting that the presence of an appropriate amount of water is important for improving the absorption capacity (Figs. 41, 42). It is preferable that water is present in an amount of 5 times or more in molar ratio to the amine, more preferably 8 times or more, and still more preferably 10 times or more. In the gel particle film added with the amine compound under optimal conditions, both the absorption amount and the desorption amount were improved by 3 to 4 times compared to the gel particle film to which no accelerator was added (Figs. 41, 42).

[0099] [Chemical formula]

[0100] Various low-molecular-weight amines were added to the gel particle film as a diffusion promoter, and the improvement effect on the amount of carbon dioxide diffusion through the gel-like film was examined. A methanol solution (100 mg / 6 mL) of the amine-containing gel particles obtained in Synthesis Example 1 was injected into a stainless-steel container and dried at 80 °C. Then, the stainless-steel container was cooled with ice from the outside to prepare a dry nanogel film. 400 μL of a 3N aqueous amine solution was uniformly dropped onto this dry nanogel film. For the gel particle film thus obtained, carbon dioxide absorption and diffusion were performed in one cycle under the same conditions as those used in the measurement of FIG. 16, and the amount of carbon dioxide diffusion was examined. The results of examining the diffusion amount using various low-molecular-weight amines are shown in FIG. 43. As shown in FIG. 43, it was confirmed that the addition of low-molecular-weight amines can promote diffusion. Also, when 400 μL was added with the concentration of the aqueous amine solution changed to 6N and when 800 μL was added with the concentration of the aqueous amine solution changed to 8N, gel particle films were prepared in the same manner, and the amount of carbon dioxide diffusion was examined. The results are shown in FIG. 44. As shown in FIG. 44, in the case of TMDAH, the amount of carbon dioxide diffusion tended to decrease when the amine concentration was too high, but it was confirmed that PMDETA and IPAE can achieve a high amount of carbon dioxide diffusion even at a high amine concentration. In particular, IPAE achieved a significantly high amount of carbon dioxide diffusion even at a high amine concentration, showing an extremely excellent effect. A high amine concentration means a situation where the amount of water relative to the amine is small, but even in such a situation with a small amount of water, IPAE achieved a significantly high amount of carbon dioxide diffusion.

Industrial Applicability

[0101] According to the present invention, a gas absorber that can efficiently absorb and diffuse acidic gases such as carbon dioxide and water vapor gas in response to external temperature changes is realized. Such a gas absorber can be effectively used in the separation and recovery process of acidic gases in CCS and the separation process of acidic gases from fuel gas, and has extremely high industrial applicability.

Explanation of Symbols

[0102] 1 Acrylic plate 2 Butyl rubber gasket 3 Gas absorber 4 Screw 5 Gas inlet 6 Gas outlet 11 Space part 12 Rectifying plate 13 Gas inlet 14 Gas outlet 21 Heat exchanger 22, 33 Desulfurizer 23 Gas absorber 24 First pipe 25 Second pipe 26 Third pipe 26a Circulation path 26b Branch path 31 First heat exchanger 32 Second heat exchanger 34 First tank 35 Second tank 36 First pipe 37 Second pipe 37a Main path 37b First path 37c Second path 38, 39 Gel particle film

Claims

1. A first gas introduction section for introducing a gas to be treated containing carbon dioxide into a first gas absorption material containing polymer compound particles having an amino group, A second gas introduction section for introducing a gas to be treated containing carbon dioxide into a second gas absorption material containing polymer compound particles having an amino group, A first heat supply section for applying heat to the first gas absorption material, A second heat supply section for applying heat to the second gas absorption material, A first gas discharge section for discharging the gas from the first gas absorption material, A second gas discharge section for discharging the gas from the second gas absorption material, An apparatus for recovering carbon dioxide, comprising: [1] Introduce the gas to be treated containing carbon dioxide from the first gas introduction section into the first gas absorption material, absorb carbon dioxide into the first gas absorption material, and discharge the unabsorbed gas from the first gas discharge section. [2] Stop introducing the gas to be treated from the first gas introduction section into the first gas absorption material. Introduce the gas to be treated containing carbon dioxide from the second gas introduction section into the second gas absorption material, absorb carbon dioxide into the second gas absorption material, and discharge the unabsorbed gas from the second gas discharge section. Apply heat to the first gas absorption material from the first heat supply section to dissipate the carbon dioxide absorbed by the first gas absorption material and discharge it from the first gas discharge section. [3] Stop introducing the gas to be treated from the second gas introduction section into the second gas absorption material. Introduce the gas to be treated containing carbon dioxide from the first gas introduction section into the first gas absorption material, absorb carbon dioxide into the first gas absorption material, and discharge the unabsorbed gas from the first gas discharge section. Apply heat to the second gas absorption material from the second heat supply section to dissipate the carbon dioxide absorbed by the second gas absorption material and discharge it from the second gas discharge section. [4] Alternately repeat the above [2] and [3]. The apparatus according to claim 1, wherein the first gas absorption material satisfies at least one of the following (1) and (2), and the second gas absorption material satisfies at least one of the following (1) and (2). (1) The water content per 1 g of solid content is 0.1 mL or more. (2) The polymer compound particles having an amino group are (meth)acrylamide-based polymer compound particles.

2. The apparatus according to claim 1, wherein the gas absorption material satisfies the above (1).

3. The apparatus according to claim 1, wherein the gas absorption material satisfies the above (2).

4. The apparatus according to claim 1, wherein the gas absorption material satisfies both the above (1) and (2).

5. The apparatus according to any one of claims 1 to 4, wherein the first gas introduction part and the second gas introduction part are provided in the path of the same gas to be treated, respectively.

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