Method for producing carbon dioxide adsorption / desorption agent, carbon dioxide adsorption / desorption agent, and method for recovering carbon dioxide using same

Abstract

One embodiment of the present invention relates to a method for producing a carbon dioxide adsorption / desorption agent, the carbon dioxide adsorption / desorption agent, or a method for recovering carbon dioxide using the same. The method for producing the carbon dioxide adsorption / desorption agent includes: a step (1) for immersing a porous carrier in a liquid containing an amine compound; and a step (2) for heating a mixture containing the porous carrier and the amine compound to cause the porous carrier and the amine compound to react with each other.

Description

Method for producing a carbon dioxide adsorbent / desorbent, carbon dioxide adsorbent / desorbent, and method for recovering carbon dioxide using the same

[0001] One embodiment of the present invention relates to a method for producing a carbon dioxide adsorbent / desorbent, a carbon dioxide adsorbent / desorbent, or a method for recovering carbon dioxide using the same.

[0002] Reducing emissions of carbon dioxide, a greenhouse gas, has long been required. However, achieving virtually zero carbon dioxide emissions is difficult and will take many years. On the other hand, Direct Air Capture (DAC), a technology that directly separates and captures carbon dioxide from the air, has recently attracted particular attention as an approach to decarbonization that differs from reducing carbon dioxide emissions.

[0003] Currently, DAC is being investigated using various devices and methods. For example, Patent Document 1 describes filling a device with particulate adsorbent, passing carbon dioxide through the device to adsorb the carbon dioxide onto the adsorbent, and then desorbing the carbon dioxide.

[0004] Japanese Patent Publication No. 2023-147269

[0005] Patent Document 1 uses a powdered zeolite molded body as an adsorbent. When attempting to fill a container with such a powdered particle dispersion, it is easy to encounter problems such as difficulty in uniformly filling the container compared to a particle dispersion in slurry form. On the other hand, filling a container with a particle dispersion in slurry form is more time-consuming than filling a container with a powdered particle dispersion. Furthermore, when performing carbon dioxide recovery treatment in such a container, it is easy to encounter problems such as a sudden increase in pressure loss due to changes in the filling state.

[0006] One embodiment of the present invention provides a carbon dioxide adsorbent that maintains good carbon dioxide adsorption characteristics, reduces pressure loss during carbon dioxide recovery processing, and exhibits excellent performance retention when the carbon dioxide adsorbent is used repeatedly.

[0007] Typical embodiments of the present invention are as follows.

[0008] [1] A method for producing a carbon dioxide adsorbent, comprising the steps of (1) immersing a porous carrier in a liquid containing an amine compound, and (2) heating a mixture containing the porous carrier and the amine compound to react the porous carrier with the amine compound. [2] The method according to [1], wherein step (2) is performed after step (1).

[0009] [3] The manufacturing method according to [1] or [2], wherein the liquid comprises at least one antioxidant selected from phenolic antioxidants and phosphorus-based antioxidants.

[0010] [4] The manufacturing method according to any one of [1] to [3], wherein the carbon dioxide adsorbent is in powder form and has a compressibility of 3 or more.

[0011] [5] The method for producing a product according to any one of [1] to [4], wherein at least one amine compound selected from the amine compound used in step (1) and the amine compound used in step (2) comprises a polyamine having a weight-average molecular weight of 300 or more. [6] The method for producing a product according to [5], wherein the polyamine having a weight-average molecular weight of 300 or more comprises polyethyleneimine or polyallylamine.

[0012] [7] A method for manufacturing the carbon dioxide adsorbent according to any one of [1] to [6], wherein the carbon dioxide adsorbent satisfies the following requirement (I): Requirement (I); 1.0000 mg of the carbon dioxide adsorbent dried in a vacuum dryer at 60°C for 8 hours is accurately weighed, and the nitrogen content in the carbon dioxide adsorbent, measured using a CHN elemental analyzer when the carbon dioxide adsorbent is burned under combustion conditions of a combustion furnace temperature of 980°C, a helium flow rate of 100 mL / min, and an oxygen flow rate of 20 mL / min, is 15% by mass or more relative to 100% by mass of the carbon dioxide adsorbent.

[0013] [8] The manufacturing method according to any one of [1] to [7], wherein the particle size of the carbon dioxide adsorbent is 30 to 500 μm.

[0014] [9] A carbon dioxide adsorbent / desorbent in powder form, wherein the carbon dioxide adsorbent / desorbent has an amine compound chemically adsorbed onto a porous carrier and an amine compound physically adsorbed onto the porous carrier, and the carbon dioxide adsorbent / desorbent has a compressibility of 3 or more.

[0015]

[10] The carbon dioxide adsorbent / desorbent according to [9], wherein at least one amine compound selected from the chemisorbing amine compound and the physiosorbing amine compound comprises a polyamine having a weight-average molecular weight of 300 or more.

[11] The carbon dioxide adsorbent / desorbent according to

[10] , wherein the polyamine having a weight-average molecular weight of 300 or more is polyethyleneimine or polyallylamine.

[0016]

[12] A carbon dioxide adsorbent according to any of [9] to

[11] , wherein the carbon dioxide adsorbent satisfies the following requirement (I): Requirement (I); 1.0000 mg of the carbon dioxide adsorbent dried in a vacuum dryer at 60°C for 8 hours is accurately weighed, and the nitrogen content in the carbon dioxide adsorbent, measured using a CHN elemental analyzer when the carbon dioxide adsorbent is burned under combustion conditions of a combustion furnace temperature of 980°C, a helium flow rate of 100 mL / min, and an oxygen flow rate of 20 mL / min, is 15% by mass or more relative to 100% by mass of the carbon dioxide adsorbent.

[0017]

[13] A method for recovering carbon dioxide, comprising the following steps (A) to (C): Step (A); filling a container having at least a gas passage with a carbon dioxide adsorbent described in any of [9] to

[12] ; Step (B); passing a gas containing carbon dioxide through the container after step (A); Step (C); heating the carbon dioxide adsorbent after step (B), or subjecting the carbon dioxide adsorbent after step (B) to a reduced pressure treatment, or heating the carbon dioxide adsorbent after step (B) while subjecting the carbon dioxide adsorbent after step (B) to a reduced pressure treatment.

[0018]

[14] The carbon dioxide recovery method described in

[13] , including step (D) below: step (D); a step of repeating steps (B) and (C) two or more times.

[0019] The carbon dioxide adsorbent according to one embodiment of the present invention maintains good carbon dioxide adsorption characteristics, has low pressure loss during carbon dioxide recovery processing, and exhibits excellent performance retention when the carbon dioxide adsorbent is repeatedly used (long lifespan). Furthermore, the carbon dioxide adsorbent according to one embodiment of the present invention has excellent handling (container filling) and energy efficiency (low energy required for carbon dioxide adsorption). Therefore, the carbon dioxide recovery method using the carbon dioxide adsorbent according to one embodiment of the present invention allows for more efficient carbon dioxide recovery. The manufacturing method for the carbon dioxide adsorbent according to one embodiment of the present invention allows for easy production of the carbon dioxide adsorbent.

[0020] The following describes in detail one embodiment for carrying out the present invention (hereinafter also referred to as "one embodiment of the present invention"). The present invention is not limited to the following description and can be implemented in various modifications within the scope of its gist. The following numerical range A to B indicates A or greater and B or less.

[0021] ≪Carbon Dioxide Adsorbent≫ A carbon dioxide adsorbent according to one embodiment of the present invention (hereinafter also referred to as "this adsorbent") is a powdered carbon dioxide adsorbent in which an amine compound is chemically adsorbed onto a porous carrier and an amine compound is physically adsorbed onto the porous carrier, and the compressibility is 3 or higher. In this invention, "powdered carbon dioxide adsorbent" does not refer to a single powdered (particle) carbon dioxide adsorbent, but rather to an aggregate of multiple powdered (particle) carbon dioxide adsorbents.

[0022] Chemical adsorption of the amine compound onto the porous support means that the porous support and the amine compound react and form a chemical bond. Specifically, this means that a functional group that is reactive to the amine present on the porous support is covalently bonded to the amine compound. Chemical adsorption of the amine compound onto the porous support can be confirmed, for example, by immersing the adsorbent in a solvent in which the amine compound dissolves (e.g., ethanol) for one day, and then checking whether nitrogen atoms are present in the adsorbent after it has been removed from the solvent (e.g., elemental analysis).

[0023] Furthermore, physical adsorption of amine compounds onto a porous support means, for example, that the amine compound is adsorbed onto the porous support by intermolecular forces (van der Waals forces), or that the porous support incorporates the amine compound into its pores. Physical adsorption of amine compounds onto a porous support can be confirmed, for example, by immersing the adsorbent in a solvent in which the amine compound dissolves (e.g., ethanol) for one day, and then checking whether nitrogen atoms are present in the solvent after removing the adsorbent (e.g., elemental analysis).

[0024] When seeking to obtain a carbon dioxide adsorbent / desorbent with superior energy efficiency and lifespan, a compressibility of 8 or higher is preferable, more preferably 10 or higher, even more preferably 13 or higher, and in some cases particularly preferable 17 or higher. On the other hand, when seeking to obtain a carbon dioxide adsorbent / desorbent with excellent container packability, a compressibility of 30 or lower is preferable, and in some cases more preferably 25 or lower. Furthermore, in order to achieve a balance between container packability, energy efficiency, and lifespan, the compressibility can be appropriately adjusted within the range of 3 to 30.

[0025] From the viewpoint of superior carbon dioxide adsorption characteristics, it is preferable that the adsorbent meets the following requirement (I). Requirement (I): 1.0000 mg of the adsorbent, dried in a vacuum dryer at 60°C for 8 hours, is accurately weighed, and the nitrogen content in the adsorbent, measured using a CHN elemental analyzer under combustion conditions of a combustion furnace temperature of 980°C, a helium flow rate of 100 mL / min, and an oxygen flow rate of 20 mL / min, is 15% by mass or more relative to 100% by mass of the adsorbent.

[0026] The nitrogen content (amine compound content in the adsorbent) in the adsorbent is more preferably 16% by mass or more, even more preferably 17% by mass or more, preferably 30% by mass or less, and even more preferably 25% by mass or less.

[0027] The particle size of this adsorbent is preferably 30 to 500 μm, more preferably 30 to 400 μm, and even more preferably 40 to 350 μm, from the viewpoint of excellent handling (container filling ability). The particle size is measured by the measurement method described in the examples below.

[0028] This adsorbent may or may not be porous, but it is preferable that it be porous from the viewpoint of superior carbon dioxide adsorption characteristics. If this adsorbent is porous, the porous carrier described below may have a similar range of pore volume and pore diameter, but usually the pore volume and pore diameter of this adsorbent tend to be smaller than those of the porous carrier used in the manufacture of this adsorbent due to physical (and chemical) adsorption of amine compounds. The pore volume and pore diameter of this adsorbent can be measured by the same method as described in the section on porous carriers below. Furthermore, the porosity of this adsorbent can also be confirmed by scanning electron microscopy (SEM) observation.

[0029] If the adsorbent is porous, it can also retain water within its pores, and the adsorbent may be adjusted to a water content suitable for carbon dioxide adsorption and desorption. One method for adjusting the water content is to pass a heated gas through a container containing the adsorbent.

[0030] The carbon dioxide adsorption capacity of this adsorbent is preferably 10 g (CO2). ２ ) / L (adsorbent / desorbent) or more, more preferably 15 g (CO ２ ) / L (adsorbent / desorbent) or more, more preferably 18g (CO ２ ) / L (adsorbent) or more, and a higher upper limit is better, for example 30g (CO ２ The amount of carbon dioxide adsorbed is less than or equal to ) / L (adsorbent). Specifically, the amount of carbon dioxide adsorbed is measured by the method described in the following examples.

[0031] The amount of carbon dioxide desorbed by this adsorbent is preferably 10 g (CO2). ２ ) / L (adsorbent / desorbent) or more, more preferably 15 g (CO ２ ) / L (adsorbent / desorbent) or more, more preferably 18g (CO ２) / L (adsorbent) or more, and a higher upper limit is better, for example 30g (CO ２ The amount of carbon dioxide desorbed is less than or equal to ) / L (adsorbent). Specifically, the amount of carbon dioxide desorbed is measured by the method described in the following examples.

[0032] The lifespan of this adsorbent is preferably 80% or more, more preferably 90% or more, and even more preferably 93% or more, with a higher upper limit being preferable, for example, 100% or less. The lifespan is specifically measured by the method described in the following examples.

[0033] <Porous Carrier> In this adsorption / desorption agent, the amine compound is chemically and physically adsorbed onto a porous carrier. The carrier only needs to be porous before the amine compound is chemically and physically adsorbed. Whether or not a carrier is porous can be determined by whether the carrier has a pore diameter and pore volume. The pore diameter can be calculated, for example, using the conventionally known BJH method, and the pore volume can be measured using the conventionally known nitrogen adsorption method. Hereinafter, for clarity, the porous carrier before the amine compound is chemically and physically adsorbed will also be referred to as the "uncontacted porous carrier".

[0034] The aforementioned non-contact porous carrier is preferably a synthetic polymer porous particle because it allows for easy adjustment of the pore diameter and pore volume of the carrier. The synthetic polymer porous particle can be produced, for example, by suspending a monomer together with a porosizing agent in an aqueous medium and polymerizing the monomer. Specific examples include a method in which a solution obtained by dissolving a polymerization initiator in a mixed solution containing a monomer and a porosizing agent is added to an aqueous medium heated to a predetermined temperature to polymerize the monomer, and a method in which a mixed solution containing a monomer and a porosizing agent is suspended in an aqueous medium, heated to a predetermined temperature, and then a polymerization initiator is added to polymerize the monomer.

[0035] Examples of monomers used in producing the aforementioned synthetic polymer porous particles include styrene monomers such as styrene, α-methylstyrene, p-methylstyrene, p-chlorostyrene, chloromethylstyrene, 4-(trimethoxysilyl)styrene, and pentafluorostyrene; aromatic vinyl crosslinkable monomers such as divinylbenzene, vinyl benzyl chloride, trivinylbenzene, divinyltoluene, divinylxylene, divinylethylbenzene, and divinylnaphthalene; glycidyl (meth)acrylate, epoxy vinylcyclohexane, 3-oxyranylpropyl (meth)acrylate, 4-oxyranylbutyl (meth)acrylate, 5-oxyranylpentyl (meth)acrylate, and 6-oxyranyl Examples of (meth)acrylate monomers having a cyclic ether group include xyl (meth)acrylate, 7-oxyranylheptyl (meth)acrylate, 8-oxyranyloctyl (meth)acrylate, (3-methyloxyranyl)methyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate glycidyl ether, glycerin mono (meth)acrylate glycidyl ether, 3,4-epoxycyclohexylmethyl (meth)acrylate, 3,4-epoxycyclohexylethyl (meth)acrylate, 3,4-epoxycyclohexylpropyl (meth)acrylate, α-(meth)acryl-ω-glycidyl polyethylene glycol, and tetrahydrofurfuryl (meth)acrylate. One monomer may be used, or two or more monomers may be used. When measuring the chemical adsorption of an amine compound onto a porous carrier using the above method, it is preferable not to use monomers containing a nitrogen atom.

[0036] Examples of porous agents used in producing the aforementioned synthetic polymer porous particles include: aliphatic hydrocarbons such as hexane, heptane, octane, nonane, decane, and undecane; alicyclic hydrocarbons such as cyclopentane and cyclohexane; aromatic hydrocarbons such as benzene, toluene, xylene, naphthalene, and ethylbenzene; halogenated hydrocarbons such as carbon tetrachloride, 1,2-dichloroethane, tetrachloroethane, and chlorobenzene; and lipids such as butanol, pentanol, hexanol, heptanol, 4-methyl-2-pentanol, 2-ethyl-1-hexanol, and 1-octanol. Examples include aliphatic alcohols; alicyclic alcohols such as cyclohexanol; aromatic alcohols such as 2-phenylethyl alcohol and benzyl alcohol; ketones such as diethyl ketone, methylhexyl ketone, methyl isobutyl ketone, diisobutyl ketone, acetophenone, 2-octanone, and cyclohexanone; ethers such as dibutyl ether, diisobutyl ether, anisole, and ethoxybenzene; esters such as isopentyl acetate, butyl acetate, 3-methoxybutyl acetate, and diethyl malonate; and linear polymers such as homopolymers of non-crosslinkable vinyl monomers. The porous agent may be used alone or in combination of two or more types.

[0037] When producing the aforementioned synthetic polymer porous particles, radical polymerization initiators are preferred as polymerization initiators. Examples of radical polymerization initiators include azo-based initiators, peroxide-based initiators, and redox-based initiators. Specific examples include azobisisobutyronitrile, dimethyl azobisisobutyrate, azobis-2,4-dimethylvaleronitrile, benzoyl peroxide, di-tert-butyl peroxide, and benzoyl-dimethylaniline peroxide. One polymerization initiator may be used, or two or more may be used.

[0038] When producing the aforementioned synthetic polymer porous particles, a water-soluble polymer may be used as needed. Examples of such water-soluble polymers include hydroxyethylcellulose, polyvinyl alcohol, carboxymethylcellulose, polyvinylpyrrolidone, starch, and gelatin. One or more of these water-soluble polymers may be used.

[0039] Preferably, the non-contacted porous carrier has a functional group reactive with amine. Examples of the functional group reactive with amine include an epoxy group (oxiranyl group), a halogen atom such as a chlorine atom, an isocyanate group, an isothiocyanate group, an aldehyde group, a carbodiimide group and a carboxy group, and among these, an epoxy group (oxiranyl group), an aldehyde group and a carboxy group are preferred.

[0040] Examples of the method for producing a non-contacted porous carrier having a functional group reactive with amine include a method of producing synthetic polymer-based porous particles by using, as a monomer used in producing the synthetic polymer-based porous particles, a monomer having a functional group reactive with amine, and a method of subjecting the obtained synthetic polymer-based porous particles to surface treatment using a compound having a functional group reactive with amine, and among these, the former method is preferred.

[0041] Examples of the monomer having a functional group reactive with amine include, among the monomers exemplified as monomers used in producing the synthetic polymer-based porous particles, a monomer having a functional group reactive with amine.

[0042] As the method for subjecting the synthetic polymer-based porous particles to surface treatment using a compound having a functional group reactive with amine, conventionally known surface treatment methods can be used. Examples of the compound having a functional group reactive with amine used in this surface treatment include an epoxy group-containing silane coupling agent, and among the monomers exemplified as monomers used in producing the synthetic polymer-based porous particles, a monomer having a functional group reactive with amine.

[0043] <Amine Compounds> This adsorption / desorption agent comprises an amine compound chemically adsorbed onto a porous carrier and an amine compound physically adsorbed onto the porous carrier. The amine compound chemically adsorbed onto the porous carrier and the amine compound physically adsorbed onto the porous carrier may be the same compound or different compounds. Furthermore, the amine compound chemically adsorbed onto the porous carrier may be one type or two or more types, and the amine compound physically adsorbed onto the porous carrier may be one type or two or more types.

[0044] From the viewpoint of easily obtaining this adsorbent / desorbent with excellent carbon dioxide adsorption characteristics, it is preferable that at least one amine compound selected from the chemiadsorbing amine compound and the physiadsorbing amine compound contains a polyamine with a weight-average molecular weight of 300 or more, more preferably that the chemiadsorbing amine compound and the physiadsorbing amine compound contain a polyamine with a weight-average molecular weight of 300 or more, and even more preferably that the chemiadsorbing amine compound and the physiadsorbing amine compound are polyamines with a weight-average molecular weight of 300 or more.

[0045] The weight-average molecular weight of the polyamine is preferably 300 or more, more preferably 600 or more, preferably 10,000 or less, and more preferably 3,000 or less.

[0046] The weight-average molecular weight of the amine compounds described herein was measured by gel permeation chromatography (GPC) using monodisperse polystyrene as the standard, under the analytical conditions of a flow rate of 1.0 mL / min, elution solvent: tetrahydrofuran, and column temperature: 40°C, using GPC columns manufactured by Tosoh Corporation (two "G2000HXL" columns, one "G3000HXL" column, and one "G4000HXL" column).

[0047] Preferred examples of the polyamine include polyethyleneimine and polyallylamine, from the viewpoint of easily obtaining this adsorbent / desorbent with excellent carbon dioxide adsorption properties, with polyethyleneimine being more preferred.

[0048] <Additives> This adsorbent may contain additives such as antioxidants, flame retardants, adhesion aids, heat conductors, and conductive agents. Each of the additives that may be included in this adsorbent may be one or two or more. The content of the additives in this adsorbent is preferably 0.01 to 0.5% by mass, more preferably 0.05 to 0.3% by mass.

[0049] When a polyamine is used as the amine compound, it is preferable that the adsorbent contains an antioxidant, from the viewpoint of suppressing discoloration of the adsorbent. Examples of such antioxidants include phenolic antioxidants and phosphorus-based antioxidants, and preferably hindered phenolic antioxidants. Examples of these antioxidants include the antioxidants described in International Publication No. 2018 / 128144, and among these, antioxidants with a high melting point (e.g., 150°C or higher) and soluble in the following solvents are preferred.

[0050] ≪Method for Producing a Carbon Dioxide Adsorbent≫ A method for producing a carbon dioxide adsorbent according to one embodiment of the present invention (hereinafter also referred to as "this method") includes the steps of: (1) immersing a porous carrier in a liquid containing an amine compound; and (2) heating a mixture containing the porous carrier and the amine compound to react the porous carrier with the amine compound. In this method, step (2) may be performed after step (1), or step (1) may be performed after step (2), but from the viewpoint of being able to produce the carbon dioxide adsorbent more easily, it is preferable to perform step (2) after step (1). Furthermore, in this method, step (1) may be performed two or more times, or step (2) may be performed two or more times. In this case, the order of steps (1) and (2) is not particularly limited. Since this method allows for the easy production of the adsorbent, a preferred example of this method is the method for producing the adsorbent.

[0051] <Step (1)> Step (1) is a step of immersing a porous carrier in a liquid containing an amine compound. The porous carrier used in Step (1) may be a porous carrier before Step (2), that is, before contact with the amine compound (corresponding to the uncontacted porous carrier), or it may be a carrier obtained after Step (2), that is, a porous carrier on which the amine compound has been chemically adsorbed, but it is preferable to use a porous carrier before Step (2), that is, before contact with the amine compound. When using a porous carrier before contact with the amine compound as the porous carrier, a wet porous carrier obtained by the method described in the section on synthetic polymer porous particles may be used, or a carrier obtained by drying the wet porous carrier may be used. By Step (1), a carrier on which the amine compound has been physically adsorbed can be obtained.

[0052] A specific example of step (1) above is a method that includes an immersion step in which a porous carrier is immersed in a liquid containing an amine compound for, for example, 12 hours to 5 days, preferably 16 hours to 2 days, at room temperature and atmospheric pressure. If a liquid containing the following solvents is used as the liquid, a solvent removal step may be performed after the immersion step to remove the solvent.

[0053] Furthermore, if step (1) is the final step in the production of the carbon dioxide adsorbent / desorbent, a drying step may be performed after the immersion step or the solvent removal step. The drying step should be performed under conditions that prevent the amine compound and the porous support from reacting (chemically). The drying temperature is, for example, 50 to 100°C, preferably 60 to 80°C, and the drying time is, for example, 4 to 24 hours, preferably 6 to 12 hours.

[0054] [Liquid containing an amine compound] The liquid into which the porous carrier is immersed is not particularly limited as long as it contains an amine compound. Examples of the amine compound include compounds similar to those described in the section on carbon dioxide adsorbents. The liquid may contain one or more amine compounds.

[0055] The content of the amine compound in the liquid is preferably 10 to 100% by mass, more preferably 20 to 85% by mass, and even more preferably 30 to 70% by mass, from the viewpoint of easily obtaining a carrier in which the amine compound is physically adsorbed onto a porous carrier.

[0056] When a liquid amine compound is used as the amine compound, the liquid may consist solely of the amine compound, but it is preferable that the liquid contains a solvent capable of dissolving or dispersing the amine compound, particularly a solvent capable of dissolving the amine compound. Examples of such solvents include conventionally known solvents such as ethers, alcohols, and esters, and among these, highly volatile alcohols such as methanol, ethanol, and isopropyl alcohol are preferred.

[0057] The liquid may contain additives as needed. Examples of such additives include those similar to those listed in the section on carbon dioxide adsorbents. One or more types of additives may be used.

[0058] It is preferable to include an antioxidant in the liquid, from the viewpoint of suppressing discoloration of the resulting carbon dioxide adsorbent / desorbent. When an antioxidant is included in the liquid, the amount of the antioxidant is preferably 0.01 to 0.5% by mass, more preferably 0.05 to 0.3% by mass.

[0059] <Step (2)> Step (2) is a step of heating a mixture containing a porous support and an amine compound to cause a (chemical) reaction between the porous support and the amine compound. The porous support used in step (2) may be the porous support before step (1), that is, before contact with the amine compound (corresponding to the uncontacted porous support), or it may be a support obtained after step (1), that is, a porous support on which the amine compound has been physically adsorbed, but it is preferable to use a support obtained after step (1). By step (2), a porous support on which the amine compound has been chemically adsorbed can be obtained.

[0060] The heating in step (2) above can be any condition that allows the amine compound and the porous support to react (chemically), and the heating temperature is, for example, 70 to 110°C, preferably 85 to 100°C, and the heating time is, for example, 6 hours to 5 days, preferably 8 hours to 3 days. Step (2) above may also be carried out under reduced pressure.

[0061] Furthermore, if, during step (2), components that may adversely affect the carbon dioxide adsorbent, such as acids (e.g., hydrochloric acid produced by the reaction of chlorine atoms in the porous carrier with an amine compound), are generated, a washing step may be performed to remove such components. From the viewpoint of being able to omit such a washing step, it is preferable that step (2) is a step in which components that may adversely affect the carbon dioxide adsorbent, such as acids, are not generated, and it is preferable to use a porous carrier having a functional group that is reactive to amines (e.g., an epoxy group) in which such components are not generated.

[0062] [Mixture containing a porous carrier and an amine compound] The mixture is not particularly limited as long as it contains a porous carrier and an amine compound. When using a porous carrier before contact with the amine compound as the porous carrier, a wet porous carrier obtained by the method described in the section on synthetic polymer porous particles may be used, or a carrier obtained by drying the wet porous carrier may be used. Also, when step (2) is performed after step (1), the mixture may be the mixture obtained in step (1) as is. Examples of amine compounds used in the mixture include compounds similar to those described in the section on carbon dioxide adsorbents. The mixture may contain one or more amine compounds.

[0063] The mixture may contain additives as needed. Examples of such additives include those similar to those listed in the section on carbon dioxide adsorbents. One or more types of additives may be used.

[0064] ≪Carbon Dioxide Recovery Method≫ The carbon dioxide recovery method according to one embodiment of the present invention can use any of the following: pressure swing type adsorption separation method, temperature swing type adsorption separation method, or pressure / temperature swing type adsorption separation method, but the temperature swing type adsorption separation method or the pressure / temperature swing type adsorption separation method is preferred. Here, the pressure swing type adsorption separation method is a pressure swing type adsorption separation method in which the pressure at which the gas is desorbed is lower than the pressure at which the gas is adsorbed, and the gas is separated by utilizing the difference between the amount of adsorbed at high pressure and the amount of adsorbed at low pressure. The temperature swing type adsorption separation method is a method in which the temperature at which the gas is desorbed is higher than the temperature at which the gas is adsorbed, and the gas is separated by utilizing the difference between the amount of adsorbed at low temperature and the amount of adsorbed at high temperature. The pressure / temperature swing type adsorption separation method and the adsorption separation method are also preferred. When using the temperature swing type adsorption separation method or the pressure / temperature swing type adsorption separation method, the desorption temperature is preferably 30°C or more higher than the adsorption temperature, and more preferably 30°C or more and 300°C or less than the adsorption temperature.

[0065] A carbon dioxide recovery method according to one embodiment of the present invention preferably includes the following steps (A) to (C): Step (A): A step of filling a container having at least a gas passage with the carbon dioxide adsorbent or the carbon dioxide adsorbent obtained by the present manufacturing method. Step (B): A step of passing a gas containing carbon dioxide through the container after step (A). Step (C): A step of heating the carbon dioxide adsorbent after step (B), or subjecting the carbon dioxide adsorbent after step (B) to a reduced pressure treatment, or heating the carbon dioxide adsorbent after step (B) while subjecting the carbon dioxide adsorbent after step (B) to a reduced pressure treatment.

[0066] Furthermore, the carbon dioxide recovery method according to one embodiment of the present invention preferably includes the following step (D) after step (C). Carbon dioxide is recovered through step (C) or the following step (D). Step (D): A step of repeating steps (B) and (C) two or more times.

[0067] When using a carbon dioxide adsorbent / desorbent according to one embodiment of the present invention, the performance of the carbon dioxide adsorbent / desorbent is maintained even after performing step (D).

[0068] One embodiment of the present invention will be described in more detail below based on the examples, but the present invention is not limited to these examples.

[0069] <Example 1> [Synthesis of CMS-DVB particles] 1.87 g of polyvinyl alcohol and 311.5 g of distilled water were added to a 500 mL separable flask equipped with a reflux tubing, a stirring blade, and a thermometer, and the mixture was stirred at 80°C for 2 hours, then cooled to room temperature. 25.94 g of chloromethylstyrene, 6.49 g of divinylbenzene, 25.85 g of 1-octanol, and 27.10 g of toluene were added, and the mixture was heated to 70°C while flowing nitrogen. A toluene solution containing 1.3 g of 2,2'-azobis(isobutyrate)dimethyl was added, and the mixture was reacted at 70°C for 7 hours. The resulting reaction solution was filtered, and the resulting particles were washed with ethanol and distilled water and filtered to remove unreacted material. The particle size was adjusted by sieving classification to obtain 85 g of wet white particles. 1.00 g of wet white particles was weighed onto an aluminum dish, baked on a hot plate at 180°C for 20 minutes, and weighed again to confirm the concentration of CMS-DVB particles (porous carrier), which are the solid components in the wet white particles. The solid component concentration was found to be 36% by mass.

[0070] [Preparation of Amine-Modified Impregnated CMS-DVB Particles] As step (2) above, the following steps were performed to obtain amine-modified CMS-DVB particles. 27.6 g of the obtained wet white particles and 62.5 g of polyethyleneimine (weight-average molecular weight [Mw]: 600) (28 mol% relative to the mol of chloromethylstyrene used in the synthesis of CMS-DVB particles) were added to a 200 mL flask and allowed to stand at 90°C for 3 days. Then, the particles were recovered by suction filtration. The recovered particles were washed and filtered 6 times with distilled water and 3 times with 1N sodium hydroxide aqueous solution, then washed and filtered again once with distilled water and once with ethanol. After that, they were dried in a vacuum dryer at 60°C for 8 hours to obtain amine-modified CMS-DVB particles in which polyethyleneimine was chemically adsorbed onto the CMS-DVB particles.

[0071] As step (1) above, the following steps were performed to prepare amine-modified impregnated CMS-DVB particles. 10.0 g of the obtained amine-modified CMS-DVB particles, 10.0 g of polyethyleneimine (weight-average molecular weight [Mw]: 1200), 20.0 g of ethanol, and 20 mg of 2,5-di-tert-butylhydroquinone were added to a 100 mL flask and allowed to stand at room temperature for 1 day. The solvent was then removed using an evaporator. Subsequently, the mixture was dried in a vacuum dryer at 60°C for 8 hours to prepare amine-modified impregnated CMS-DVB particles.

[0072] [Measurement of loose bulk density] The amine-modified impregnated CMS-DVB particles were dried for 8 hours using a vacuum dryer set to 60°C. These dried amine-modified impregnated CMS-DVB particles were referred to as the "sample" for the measurement of density and compressibility. Next, the sample was placed in a 10 mL glass graduated cylinder (Φ14 mm, height 180 mm, made of hard glass, graduation 0.1 mL) that had been electrostatically neutralized, so that the filling volume was 5 mL. The cylinder was electrostatically neutralized again, and the mass (mass when filled to 5 mL without tapping) was measured. The mass per 5 mL of sample was calculated by subtracting the mass of the graduated cylinder alone from the measured mass, and the loose bulk density of the sample was determined. As a result, the loose bulk density of the sample was 0.38 g / mL.

[0073] [Measurement of Compressibility] The volume of a graduated cylinder filled with 5 mL of the sample used for measuring loose bulk density was measured after tapping it 40 times on the laboratory bench. The hard bulk density of the sample was calculated from this volume after tapping and the mass of the filled sample. The results are shown in Table 1.

[0074] Next, the compressibility (C) of the sample was determined from the values ​​of the loose bulk density (ρP) and the stiff bulk density (ρA) of the sample using the following formula. The results are shown in Table 1. In Table 1, a compressibility greater than 17 is expressed as ">17", a compressibility of 17 or less and greater than 13 is expressed as ">13", a compressibility of 13 or less and greater than 8 is expressed as ">8", a compressibility of 8 or less and greater than 5 is expressed as ">5", a compressibility of 5 or less and greater than 3 is expressed as ">3", and a compressibility less than 3 is expressed as <3.

[0075] C = (ρP - ρA) / ρP × 100 C: Compression ρP: Loose bulk density (density before tapping) ρA: Stiff bulk density (density after 40 taps)

[0076] Furthermore, when a graduated cylinder that had been tapped 40 times was tapped another 40 times, no change was observed between the volume after 40 taps and the volume after a total of 80 taps.

[0077] [Measurement of Amine Content (Nitrogen Content in Carbon Dioxide Adsorbent)] 1.0000 mg of the amine-modified impregnated CMS-DVB particles, dried in a vacuum dryer at 60°C for 8 hours, was accurately weighed. The amine-modified impregnated CMS-DVB particles were then burned and analyzed using a CHN elemental analyzer (manufactured by EuroVector) under the following combustion conditions. The total nitrogen content (unit: mass%) in 100% by mass of the amine-modified impregnated CMS-DVB particles was measured as the amine content. The amine content in the amine-modified impregnated CMS-DVB particles is shown in Table 1.

[0078] Combustion conditions: Furnace temperature: 980°C, Helium flow rate: 100 mL / min, Oxygen flow rate: 20 mL / min

[0079] [Measurement of Particle Size] The amine-modified impregnated CMS-DVB particles were observed using a scanning electron microscope, and images of the samples were taken at multiple magnifications. The average particle size was calculated by analyzing the particle sizes of at least 10 samples from the obtained images. The particle sizes of the amine-modified impregnated CMS-DVB particles are shown in Table 1.

[0080] [Measurement of Pressure Loss] The amine-modified impregnated CMS-DVB particles were dried for 8 hours using a vacuum dryer with the inside of the dryer set to 60°C. The dried sample was filled into a measurement pipe, and pressure sensors were installed at both ends of the pipe so that changes in the pressure of air inside the pipe could be measured. Thereafter, air was introduced into the pipe at a flow rate determined using an air flow meter, and pressure loss was evaluated from the pressure difference in the sample-filled portion. When the compression loss of the sample-filled portion is 80% or less compared to the result of Comparative Example 1, it is rated A; when it is more than 80% and 90% or less, it is rated B; when it is more than 90% and 95% or less, it is rated C. The results are shown in Table 1.

[0081] [Measurement of Adsorption Amount (Carbon Dioxide Adsorption Amount)] A certain amount of the amine-modified impregnated CMS-DVB particles, which had been dried in a vacuum dryer at 60°C for 8 hours, was quantified, and vacuum degassing treatment was performed at 80°C for 8 hours using a pretreatment device BELPREP-VACII (manufactured by Microtrac). The amine-modified impregnated CMS-DVB particles after this vacuum degassing treatment were introduced into a device BELSORP-MAXII-HP (manufactured by Microtrac) for measuring carbon dioxide adsorption amount. Adsorption properties were evaluated using the constant volume method. Using carbon dioxide as the adsorbate, an adsorption isotherm was obtained under saturated vapor pressure at a temperature of 298.15 K. The calculation was performed with the molecular cross-sectional area of the adsorbate being 0.216 nm ２ The calculation was performed with the molecular cross-sectional area of the adsorbate being 0.216 nm. For the equilibrium waiting time at each measurement point, the pressure change over 500 seconds was set to be within 0.2% of the reading of the pressure gauge. Among the measurement results of the adsorption isotherm, the carbon dioxide adsorption amount at the point closest to a pressure of 0.04 kPa was evaluated. When the carbon dioxide adsorption amount is 15 g (CO ２ 2) / L (adsorption / desorption agent) or more, it is evaluated as A (good); when it is less than 15 g / L and 10 g / L or more, it is evaluated as B (acceptable); when it is less than 10 g / L, it is evaluated as C (unacceptable). The results are shown in Table 1.

[0082] [Measurement of Desorption Amount (Carbon Dioxide Desorption Amount)] The amine-modified impregnated CMS-DVB particles, dried in a vacuum dryer at 60°C for 8 hours, were quantified and introduced into a BELCAT II (Microtrac) device for measuring carbon dioxide desorption. The particles were heated at 80°C for 8 hours under a helium gas flow of 25 mL / min, then cooled to 25°C and held at 25°C. A 400 ppm carbon dioxide / helium gas flow rate of 25 mL / min was passed through these amine-modified impregnated CMS-DVB particles held at 25°C for 60 minutes. During this time, the outlet gas concentration was monitored with a mass spectrometer to confirm that saturation adsorption had occurred. Next, the flowing gas was switched to 25 mL / min of helium and held for a certain period of time to remove carbon dioxide from the gas phase. Then, the temperature of the amine-modified impregnated CMS-DVB particles was raised to 80°C, and the gas components desorbed from the particles were monitored using a mass spectrometer. The amount of carbon dioxide desorbed was detected by the peak at m / z = 44. Furthermore, the amount of carbon dioxide desorbed was quantified by comparing it with the mass spectrometry results for carbon dioxide gas of known concentration. The amount of carbon dioxide desorbed was 15 g (CO2). ２ A value of A (Good) was given if the amount was 10 g / L or more but less than 15 g / L, a value of B (Acceptable) was given if it was less than 10 g / L, and a value of C (Unacceptable) was given if it was less than 10 g / L.

[0083] [Measurement of Lifespan] The amine-modified impregnated CMS-DVB particles were introduced into a vacuum dryer. Next, as an adsorption step, the particles were exposed to normal air containing carbon dioxide for 30 minutes at room temperature and pressure, and then as a desorption step, they were heated at 80°C under reduced pressure for 30 minutes and cooled to room temperature. The adsorption and desorption steps constituted one cycle, and this was repeated 200 times. After that, the amount of carbon dioxide adsorbed was measured using the same method as for measuring the adsorption amount. With the amount of carbon dioxide adsorbed in the first cycle set to 100%, the amount of carbon dioxide adsorbed in the 200th cycle was evaluated as A (Good) if it was 90% or more, B (Acceptable) if it was between 80% and 90%, and C (Unacceptable) if it was less than 80%. The results are shown in Table 1.

[0084] <Example 2> [Synthesis of GMA-DVB particles] 1.20 g of polyvinyl alcohol and 200 g of distilled water were added to a 500 mL separable flask equipped with a reflux tubing, a stirring blade, and a thermometer, and stirred at 80°C for 2 hours, then cooled to room temperature. 5.71 g of glycidyl methacrylate, 1.43 g of divinylbenzene, 13.4 g of methylhexyl ketone, and 1.06 g of acetophenone were added, and the mixture was heated to 70°C while flowing nitrogen. An acetophenone solution containing 0.53 g of 2,2'-azobis(isobutyrate)dimethyl was added, and the mixture was reacted at 70°C for 2 hours. The resulting reaction solution was filtered, and the resulting particles were washed with ethanol and distilled water and filtered to remove unreacted material. The particle size was adjusted by sieving classification, and 50 g of slurry was recovered with distilled water. 1.00 g of the recovered slurry was weighed onto an aluminum dish, baked on a hot plate at 180°C for 20 minutes, and weighed again to confirm the solid content concentration of the white particles in the slurry, which are GMA-DVB particles (porous carriers). The solid content concentration was found to be 8% by mass.

[0085] [Preparation of Amine-Modified Impregnated GMA-DVB Particles] As step (1) above, the following steps were performed to obtain amine-impregnated GMA-DVB particles. 50.0 g of the obtained wet white particles, 16 g of ethanol, and 8.0 g of polyethyleneimine (weight-average molecular weight [Mw]: 1200) were added to a 300 mL flask, and after standing at room temperature for 1 day, the solvent was removed using an evaporator to obtain amine-impregnated GMA-DVB particles.

[0086] As step (2) above, the following steps were performed to produce amine-modified impregnated GMA-DVB particles. The obtained amine-modified impregnated GMA-DVB particles were dried in a vacuum dryer at 90°C for 8 hours to produce amine-modified impregnated GMA-DVB particles in which polyethyleneimine was chemically adsorbed onto the GMA-DVB particles.

[0087] <Examples 3-6> In Example 1, amine-modified impregnated CMS-DVB particles were prepared in the same manner as in Example 1, except that the amine species used in step (1) and / or step (2) were changed as shown in Table 1. Various measurements were performed in the same manner as in Example 1, except that the prepared amine-modified impregnated CMS-DVB particles were used. The results are shown in Table 1.

[0088] <Comparative Example 1> [Preparation of Amine-Modified CMS-DVB Particles] As step (2) above, the following steps were performed to obtain amine-modified CMS-DVB particles. 27.6 g of wet white particles obtained in the same manner as in Example 1 and 62.5 g of polyethyleneimine (weight-average molecular weight [Mw]: 600) (28 mol% relative to the mol of chloromethylstyrene used in the synthesis of CMS-DVB particles) were added to a 200 mL flask and left to stand at 90°C for 3 days. Then, the particles were recovered by suction filtration. The recovered particles were washed and filtered 6 times with distilled water and 3 times with 1N sodium hydroxide aqueous solution, then washed and filtered again once with distilled water and once with ethanol. After that, they were dried in a vacuum dryer at 60°C for 8 hours to produce amine-modified CMS-DVB particles in which polyethyleneimine was chemically adsorbed onto the CMS-DVB particles. Various measurements were performed in the same manner as in Example 1, except that the prepared amine-modified CMS-DVB particles were used. The results are shown in Table 1.

[0089] <Comparative Example 2> [Synthesis of ST-DVB Particles] Moist white particles were obtained in the same manner as in Example 1, except that 17.50 g of styrene was used instead of chloromethylstyrene, which was the raw material, when synthesizing CMS-DVB particles in Example 1.

[0090] [Preparation of Amine-Impregnated ST-DVB Particles] As step (1) above, the following steps were performed to prepare amine-impregnated ST-DVB particles. 27.6 g of the obtained wet white particles, 10.0 g of polyethyleneimine (weight-average molecular weight [Mw]: 1200), and 2.4 g of ethanol were added to a 200 mL flask and left to stand at room temperature for 1 day. The solvent was then removed using an evaporator. Subsequently, the mixture was dried in a vacuum dryer at 60°C for 8 hours to prepare amine-impregnated ST-DVB particles. Various measurements were performed in the same manner as in Example 1, except that the prepared amine-impregnated ST-DVB particles were used. The results are shown in Table 1.

[0091]

Claims

1. A method for producing a carbon dioxide adsorbent / desorbent, comprising the steps of: (1) immersing a porous carrier in a liquid containing an amine compound; and (2) heating a mixture containing the porous carrier and the amine compound to react the porous carrier with the amine compound.

2. The manufacturing method according to claim 1, wherein step (2) is performed after step (1).

3. The manufacturing method according to claim 1, wherein the liquid contains at least one antioxidant selected from phenolic antioxidants and phosphorus-based antioxidants.

4. The manufacturing method according to claim 1, wherein the carbon dioxide adsorbent / desorbent is in powder form and has a compressibility of 3 or more.

5. The manufacturing method according to claim 1, wherein at least one amine compound selected from the amine compound used in step (1) and the amine compound used in step (2) contains a polyamine having a weight-average molecular weight of 300 or more.

6. The production method according to claim 5, wherein the polyamine having a weight-average molecular weight of 300 or more includes polyethyleneimine or polyallylamine.

7. A method for manufacturing the carbon dioxide adsorbent according to claim 1, wherein the carbon dioxide adsorbent satisfies the following requirement (I): Requirement (I); 1.0000 mg of the carbon dioxide adsorbent dried in a vacuum dryer at 60°C for 8 hours is accurately weighed, and the nitrogen content in the carbon dioxide adsorbent, measured using a CHN elemental analyzer under combustion conditions of a combustion furnace temperature of 980°C, a helium flow rate of 100 mL / min, and an oxygen flow rate of 20 mL / min, is 15% by mass or more relative to 100% by mass of the carbon dioxide adsorbent.

8. The manufacturing method according to claim 1, wherein the particle size of the carbon dioxide adsorbent / desorbent is 30 to 500 μm.

9. A carbon dioxide adsorbent / desorbent in powder form, wherein the carbon dioxide adsorbent / desorbent has an amine compound chemically adsorbed onto a porous carrier and an amine compound physically adsorbed onto the porous carrier, and the carbon dioxide adsorbent / desorbent has a compressibility of 3 or more.

10. The carbon dioxide adsorbent / desorbent according to claim 9, wherein at least one amine compound selected from the chemisorbing amine compound and the physicosorbing amine compound comprises a polyamine having a weight-average molecular weight of 300 or more.

11. The carbon dioxide adsorbent / desorbent according to claim 10, wherein the polyamine having a weight-average molecular weight of 300 or more is polyethyleneimine or polyallylamine.

12. The carbon dioxide adsorbent according to claim 9, wherein the carbon dioxide adsorbent satisfies the following requirement (I): Requirement (I); 1.0000 mg of the carbon dioxide adsorbent dried in a vacuum dryer at 60°C for 8 hours is accurately weighed, and the nitrogen content in the carbon dioxide adsorbent, measured using a CHN elemental analyzer when the carbon dioxide adsorbent is burned under combustion conditions of a combustion furnace temperature of 980°C, a helium flow rate of 100 mL / min, and an oxygen flow rate of 20 mL / min, is 15% by mass or more relative to 100% by mass of the carbon dioxide adsorbent.

13. A method for recovering carbon dioxide, comprising the following steps (A) to (C): Step (A); filling a container having at least a gas passage with a carbon dioxide adsorbent described in any one of claims 9 to 12; Step (B); passing a gas containing carbon dioxide through the container after step (A); Step (C); heating the carbon dioxide adsorbent after step (B), or subjecting the carbon dioxide adsorbent after step (B) to a reduced pressure treatment, or heating the carbon dioxide adsorbent after step (B) while subjecting the carbon dioxide adsorbent after step (B) to a reduced pressure treatment.

14. A method for recovering carbon dioxide according to claim 13, comprising the following step (D): Step (D); a step of repeating steps (B) and (C) two or more times.

Images