Composition for carbon dioxide separation, solid absorbent material for carbon dioxide separation using the same, and method for manufacturing solid absorbent material for carbon dioxide separation

Abstract

[Technical Problem] This invention provides a method for efficiently separating or recovering carbon dioxide from a gas composition containing low partial pressure and / or low concentration of carbon dioxide. [Solution] The carbon dioxide separation composition of this invention comprises an oligomeric amine compound having a boiling point of 200°C or higher and a modifier having a boiling point of 200°C or higher, wherein a portion of all nitrogen atoms in the oligomeric amine compound has a carbamic acid or salt structure thereof, and the proportion of nitrogen atoms forming the carbamic acid or salt structure of the oligomeric amine compound is 0.1% to 20% relative to the total nitrogen atoms of the oligomeric amine compound.

Description

Technical Field

[0001] The present invention relates to a composition for carbon dioxide separation, a solid absorbent material for carbon dioxide separation using the composition, and a method for manufacturing the solid absorbent material for carbon dioxide separation. Background Technology

[0002] In recent years, various carbon dioxide separation and recovery technologies have been developed to achieve carbon neutrality. Representative carbon dioxide separation and recovery technologies include chemical absorption, physical absorption, and membrane separation (Patent Documents 1 and 2 and Non-Patent Document 1).

[0003] Chemical absorption is a technique that uses a medium such as amine compounds that bind to carbon dioxide to separate carbon dioxide through a chemical reaction between the medium and the carbon dioxide. The absorption and release of carbon dioxide requires a large amount of energy. On the other hand, it is an indispensable technology for recovering carbon dioxide from gases containing low partial pressure or low concentration of carbon dioxide, such as recovering carbon dioxide from the atmosphere (Non-Patent Literature 2).

[0004] Chemical absorption methods include absorbent liquid systems and solid absorbent material systems. In recovering carbon dioxide from gases containing low partial pressure or low concentrations of carbon dioxide, it is necessary to bring a large amount of gas into contact with the absorbent component. Therefore, solid absorbent material systems with low pressure loss are considered promising. In solid absorbent material systems, solid absorbent materials with the absorbent component immobilized or supported on porous materials are used to absorb or adsorb carbon dioxide (Non-Patent Document 3).

[0005] For example, Non-Patent Literature 4 reports a system that effectively recovers carbon dioxide from gases such as the atmosphere containing low partial pressure or low concentration of carbon dioxide, using regular mesoporous silica, represented by SBA-15, as a porous material, and blending polyethylene glycol and polyethyleneimine as absorbent components.

[0006] Existing technical documents

[0007] Patent documents

[0008] Patent Document 1: International Publication No. 2019 / 040445

[0009] Patent Document 2: International Publication No. 2017 / 146231

[0010] Non-patent literature

[0011] Non-patent literature 1: Tomoki Kamiya et al., "CO2 Separation from Air by Nanoparticle-Supported Liquid Membranes of Amine and Ionic Liquid Mixtures", Journal of Chemical Engineering of Japan, Vol. 49 (7), pp. 607-613, 2016, Japan Chemical Engineering Society

[0012] Non-patent document 2: MMFaruque Hasan et al., "Modeling, Simulation, andOptimization of Postcombustion CO2 Capture for Variable Feed Concentration and Flow Rate.2.Pressure Swing Adsorption and Vacuum Swing AdsorptionProcesses", Industrial & Engineering Chemistry Research 2012, Volume 51, Pages 15665-15682

[0013] Non-Patent Literature 3: Dr. Xinhua Shen et al., "Polyethylenimine Applications in Carbon Dioxide Capture and Separation: From Theoretical Study to Experimental Work", ENERGY TECHNOLOGY 2017, Vol. 5, pp. 822-833

[0014] Non-patent literature 4: Miles A. Sakwa-Novak et al., "Role of Additives in CompositePEI / Oxide CO2 Adsorbents: Enhancement in the Amine Efficiency of Supported PEI by PEG in CO2 Capture from Simulated Ambient Air", Applied Materials & Interfaces, 2015, Vol. 7, pp. 24748-24759. Summary of the Invention

[0015] However, in the popularization and commercialization of solid absorbent materials using regular mesoporous silica, there are two major problems: (1) the availability of porous materials and (2) adsorption-desorption performance. The following will explain each problem.

[0016] (1) Regarding the availability of porous materials: Regular mesoporous silica, represented by SBA-15, is characterized by a structure in which pores of uniform diameter are regularly arranged into medium-sized structures and a large surface area. However, in order to precisely control the pore structure, a complex manufacturing process is required. For example, according to non-patent literature 4, SBA-15 is synthesized by the following method: using surfactants such as Pluronic (registered trademark) P123 as template compounds, adding silica raw materials such as tetraalkoxysilane, forming a regular liquid crystal layer with a hexagonal structure composed of rod-shaped micelles, and sintering the resulting organic-inorganic composite material.

[0017] Mesoporous silica, which requires complex manufacturing processes, is not readily available as a porous material and is expensive. Therefore, in order to enable the social installation and large-scale popularization of solid absorbent material systems for gases containing low partial pressure or low concentration of carbon dioxide, it is necessary to develop solid absorbent materials that can effectively utilize highly versatile porous materials.

[0018] (2) Regarding the adsorption-desorption performance: In solid absorbent materials using regular mesoporous silica as a porous material, it is important that carbon dioxide diffuses into the pores that maintain the interconnected structure of the absorbent component. According to Non-Patent Literature 4, a research group from the Georgia Institute of Technology reported that by adding polyethylene glycol to polyethyleneimine, which is used as an absorbent component, the diffusion of carbon dioxide into the pores is facilitated, and excellent performance of carbon dioxide adsorption-desorption per 1 mole of amine (hereinafter also referred to as "amine efficiency") exceeding 0.2 mmol-CO2 / mmol-N can be achieved.

[0019] However, even the excellent solid absorbent disclosed in Non-Patent Document 4 cannot achieve a carbon dioxide adsorption and desorption capacity of 0.8 mmol / g per gram of solid absorbent material for a hypothetical atmosphere of 400 ppm carbon dioxide-containing gas. The theoretical carbon dioxide recovery in one cycle is only 35g per kg of solid absorbent material, which is inefficient. In solid absorbent material systems targeting gases with low partial pressure or low concentration of carbon dioxide, there is a significant gap between its performance and practical application.

[0020] As mentioned above, a solid absorbent material that can simultaneously solve (1) the problem of the availability of porous materials and (2) the problem of adsorption-desorption performance, and efficiently recover carbon dioxide from gases containing low partial pressure or low concentration of carbon dioxide, has not yet been developed. Therefore, in order to achieve social installation and large-scale popularization of solid absorbent material systems for gases containing low partial pressure or low concentration of carbon dioxide, it is necessary to develop solid absorbent materials that can achieve both high amine efficiency and high carbon dioxide recovery per unit weight.

[0021] Therefore, the object of the present invention is to provide a method for efficiently separating or recovering carbon dioxide from a gas composition containing low partial pressure and / or low concentration of carbon dioxide.

[0022] The inventors have conducted in-depth research on methods for solving the above-mentioned problems. As a result, the inventors discovered that the above-mentioned objectives can be achieved through a composition for carbon dioxide separation, thereby completing the present invention. The composition for carbon dioxide separation comprises an oligomeric amine compound with a boiling point of 200°C or higher and a modifier with a boiling point of 200°C or higher, wherein a portion of all nitrogen atoms in the oligomeric amine compound has an amino carboxylic acid structure or a salt thereof. Detailed Implementation

[0023] The embodiments of the present invention will now be described in detail. The embodiments shown herein are illustrative examples to embody the technical concept of the present invention and are not intended to limit the invention. Therefore, other implementable methods, usage methods, and techniques that can be conceived by those skilled in the art without departing from the spirit of the present invention are included within the scope and spirit of the present invention, and are also included within the scope of the claims and their equivalents. The embodiments described in this specification can be combined in any way to form other embodiments. Unless otherwise specified, measurements of operation and physical properties are performed at room temperature (20–25°C) and relative humidity 45–55%RH.

[0024] In this specification, the range “X~Y” means “above X and below Y”. Furthermore, in this specification, “and / or” is used to mean at least one of the listed constituent elements. For example, “A and / or B” includes only A, only B, and combinations of A and B. In this specification, where the expression “~acid (salt)” is used, it means “~acid and / or its salt”. Additionally, in this specification, “weight” and “mass,” “weight%” and “mass%”, and “parts by weight” and “parts by mass” are treated as synonyms.

[0025] Examples of the Invention

[0026] The present invention includes the following schemes and methods.

[0027] [1] A composition for carbon dioxide separation, comprising an oligoamine compound having a boiling point of 200°C or higher and a modifier having a boiling point of 200°C or higher, wherein a portion of all nitrogen atoms of the oligoamine compound has a carbamic acid or salt structure thereof, and the proportion of nitrogen atoms forming the carbamic acid or salt structure of the oligoamine compound is 0.1% to 20% relative to all nitrogen atoms of the oligoamine compound;

[0028] [2] According to the carbon dioxide separation composition described in [1] above, the water content is 1% to 30% by weight relative to the total weight of the carbon dioxide separation composition.

[0029] [3] The composition for carbon dioxide separation according to [1] or [2] above, wherein the oligoamine compound is polyethyleneimine with a number average molecular weight of 200 or more and less than 2000;

[0030] [4] The composition for carbon dioxide separation according to any one of [1] to [3] above, wherein the oligoamine compound is a compound in which the primary amine structure accounts for more than 5% of the total amine structure;

[0031] [5] The composition for carbon dioxide separation according to any one of [1] to [4] above, wherein the HSP value of the modifier is ΔD of 12 or more and 22 or less, ΔP of 5 or more and 15 or less, and ΔH of 3 or more and 30 or less;

[0032] [6] The composition for carbon dioxide separation according to any one of [1] to [5] above, wherein the modifier is a compound having a polyethylene glycol structure;

[0033] [7] A solid absorbent material for carbon dioxide separation, which is formed by loading the carbon dioxide separation composition described in any one of [1] to [6] above onto hydrophilic silica gel;

[0034] [8] The solid absorbent material for carbon dioxide separation according to [7] above, wherein the physical properties of the hydrophilic silica gel satisfy one or more of the group consisting of (i) to (iv) below;

[0035] (i) Pore volume 0.6cm 3 / g~3.0cm 3 / g;

[0036] (ii) The average pore size is 5 nm to 80 nm;

[0037] (iii) Specific surface area is 70m² 2 / g~800m 2 / g;

[0038] (iv) Specific gravity is 0.10 g / cm³ 3 above;

[0039] [9] The solid absorbent material for carbon dioxide separation according to [7] or [8] above satisfies that it is selected from one or more of the group consisting of (i) and (ii) below;

[0040] (i) In the carbon dioxide adsorption-desorption test using air with a carbon dioxide concentration of 300 to 500 ppm and an absolute humidity of 2 g / kg or less, in the process of releasing the carbon dioxide absorbed by the above-mentioned solid absorbent material at 40°C at 70°C, the amount of carbon dioxide adsorbed and desorbed per gram of solid absorbent material is 0.90 mmol or more, and the amount of carbon dioxide adsorbed and desorbed per mole of amine contained in the solid absorbent material is 0.20 mol or more.

[0041] (ii) In the carbon dioxide adsorption-desorption test using air with a carbon dioxide concentration of 9000 ppm to 11000 ppm and an absolute humidity of 2 g / kg or less, in the process of releasing the carbon dioxide absorbed by the above-mentioned solid absorbent material at 70°C at 100°C, the amount of carbon dioxide adsorbed and desorbed per gram of solid absorbent material is 1.30 mmol or more, and the amount of carbon dioxide adsorbed and desorbed per mole of amine contained in the solid absorbent material is 0.20 mol or more.

[0042]

[10] A method for manufacturing a solid absorbent material for carbon dioxide separation, comprising: (1) a first step of preparing an impregnation liquid containing an oligoamine compound having a boiling point of 200°C or higher, a modifier having a boiling point of 200°C or higher, and water; (2) a second step of impregnating a hydrophilic silica gel in the impregnation liquid; (3) a third step of separating the hydrophilic silica gel impregnated with the impregnation liquid from an excess of the impregnation liquid; and (4) a fourth step of drying the hydrophilic silica gel impregnated with the impregnation liquid by evaporating water in an atmosphere containing carbon dioxide.

[0043]

[11] The method for manufacturing solid absorbent material for carbon dioxide separation according to

[10] above satisfies that it is selected from one or more of the group consisting of (a) to (c) below;

[0044] (a) The second process is carried out in a temperature range of 20°C to 90°C;

[0045] (b) The second step includes a step of degassing the porous material under a reduced pressure of -0.08 MPaG to -0.004 MPaG;

[0046] (c) The fourth process uses air as an atmosphere containing carbon dioxide and is carried out in a temperature range of 30°C to 100°C.

[0047] According to the above-described carbon dioxide separation composition, when supported on a porous material or similar carrier (especially hydrophilic silica gel, i.e., constituting a solid absorbent material), carbon dioxide can be efficiently separated or recovered from a gas composition containing low partial pressure and / or low concentration carbon dioxide. More specifically, according to the above-described carbon dioxide separation composition, excellent absorption sites for carbon dioxide absorption and desorption are easily formed within the micropores and mesopores of the hydrophilic silica gel. Therefore, when the above-described carbon dioxide separation composition is supported on a porous material or similar carrier (i.e., constituting a solid absorbent material), the solid absorbent material can efficiently absorb and desorb carbon dioxide from a gas composition containing low partial pressure and / or low concentration carbon dioxide. In other words, the carbon dioxide separation composition of this type can be suitably supported on hydrophilic silica gel, and can be a carbon dioxide separation composition supported on hydrophilic silica gel.

[0048] Furthermore, based on the aforementioned solid absorbent material, it is possible to obtain a solid absorbent material that achieves a high level of both carbon dioxide adsorption / desorption capacity per gram of solid absorbent material and carbon dioxide adsorption / desorption capacity per mole of amine (amine efficiency), thereby providing a technology for efficiently separating or recovering carbon dioxide from gas compositions containing low partial pressure and / or low concentration of carbon dioxide.

[0049] Furthermore, according to the above-described method for manufacturing solid absorbent materials, the aforementioned carbon dioxide separation composition can easily permeate into the micropores and mesopores of the hydrophilic silica gel, and be concentrated while remaining within the micropores and mesopores of the hydrophilic silica gel. Thus, a solid absorbent material with excellent absorption and desorption sites for carbon dioxide can be obtained, providing a solid absorbent material that can efficiently absorb and desorb carbon dioxide from gas compositions containing low partial pressure and / or low concentrations of carbon dioxide.

[0050] In developing the carbon dioxide separation composition of this method, the inventors conducted in-depth research as follows. First, the carrier for supporting the carbon dioxide separation composition was studied. The inventors focused on silica gel as a readily available porous material. Silica gel synthesized via a gelation method using sodium silicate and inorganic acids is readily available and inexpensive. Furthermore, since silica gel has large macropores connected to micropores or mesopores within its structure, it was envisioned that if the absorbent components could be effectively loaded into the micropores or mesopores, the diffusion of carbon dioxide within the pores could be accelerated, thus preparing a high-performance solid absorbent material.

[0051] However, due to its complex and interwoven network pore structure, general-purpose silica gel does not easily allow amine components to permeate and be impregnated and supported, making it difficult to use general-purpose silica gel as a porous material to constitute solid absorbent materials (Non-Patent Document 3: ENERGY TECHNOLOGY 20175, pp. 822-833).

[0052] The inventors conducted in-depth research and found that the reason why porous materials, such as silica gel, are difficult to use as solid absorbent materials lies in the composition used for carbon dioxide separation. It is known that the pore surfaces of regular mesoporous silica used as a porous material in the prior art have hydrophobic properties (Non-Patent Literature 5: David P. Serrano et al., "Adsorption and Hydrophobic Properties of Mesostructured MCM-41 and SBA-15 Materials for Volatile Organic Compound Removal", Industrial & Engineering Chemistry Research 2004, Vol. 43, pp. 7010-7018). To date, organic solvents such as methanol or ethanol have been used as diluents for carrying absorbent components (Non-Patent Literature 4: Miles A. Sakwa-Novak et al., "Role of Additives in Composite PEI / Oxide CO2 Adsorbents: Enhancement in the Amine Efficiency of Supported PEI by PEG in CO2 Capture from Simulated Ambient Air", APPLIED MATERIALS & INTERFACES, 2015, Vol. 7, pp. 24748-24759).

[0053] On the other hand, the inner surface of silica gel is a hydrophilic surface rich in silanol groups, making it difficult for absorbent components to penetrate and remain in the micropores or mesopores of silica gel in carbon dioxide separation compositions formulated for regular mesoporous silica.

[0054] Therefore, by inventing a carbon dioxide separation composition suitable for the properties of the hydrophilic pore inner surface of silica gel, the inventors are able to effectively load the absorbent component into the micropores and mesopores of silica gel.

[0055] Specifically, it was discovered that by using a composition containing a specific amount of an oligomeric amine compound with a carbamic acid (salt) structure and a modifier, the absorbent component can effectively penetrate and remain within the micropores and mesopores of hydrophilic silica gel, thus completing the present invention.

[0056] Therefore, the object of the present invention is to provide a solid absorbent material for the social installation and widespread adoption of solid absorbent material systems for gases containing low partial pressure and / or low concentrations of carbon dioxide, in order to: (1) construct the solid absorbent material using a universally available porous material; and (2) achieve a high balance between carbon dioxide recovery per unit weight of solid absorbent material and carbon dioxide adsorption / desorption efficiency per mole of amine. Furthermore, according to the present invention, a method is provided for efficiently separating or recovering carbon dioxide from gas compositions containing low partial pressure and / or low concentrations of carbon dioxide.

[0057] A. Composition for Carbon Dioxide Separation

[0058] The carbon dioxide separation composition of this method comprises an oligoamine compound with a boiling point of 200°C or higher and a modifier with a boiling point of 200°C or higher. A portion of all nitrogen atoms in the oligoamine compound has a carbamic acid or salt structure. The proportion of nitrogen atoms forming the carbamic acid or salt structure in the oligoamine compound is 0.1% to 20% relative to the total nitrogen atoms in the oligoamine compound. Hereinafter, the carbamic acid or salt structure will be referred to as the "carbamic acid (salt) structure".

[0059] <Oligamine Compounds>

[0060] Oligoamine compounds are compounds having multiple amino groups. In this specification, oligoamine compounds are polyamine compounds with an index-average molecular weight of less than 2000. In the carbon dioxide separation composition of this type, the oligoamine compound has a boiling point of 200°C or higher at atmospheric pressure. Furthermore, in the carbon dioxide separation composition of this type, regarding the oligoamine compound, a portion of all nitrogen atoms (amino groups) of the oligoamine compound has an urethane (salt) structure, and the proportion of nitrogen atoms forming urethane or its salt structure in the oligoamine compound is 0.1% to 20% relative to the total nitrogen atoms of the oligoamine compound.

[0061] Here, the structure of carbamic acid or its salt is -N. + HR 1 R 2 -COOH or -N + HR 1 R 2 -COO - (R) 1 and R 2 Each group is an independent hydrogen atom or a hydrocarbon group that may have substituents. R1 and R 2 This is equivalent to the amino group present in oligoamine compounds. Therefore, R 1 and R 2 Preferably, a hydrocarbon group with 1 to 20 hydrogen atoms or carbon atoms is used as R. 1 and R 2 The substituents are preferably primary to tertiary amino groups. The carbamic acid or its salt in the oligoamine compound is formed by reaction with carbon dioxide, as shown in formula (i) or (ii) below.

[0062] [Chemical Formula 1]

[0063]

[0064] In the carbon dioxide separation composition of this method, a portion of the amino group (amine structure) of the oligoamine compound forms a carbamic acid (salt) structure. The proportion of nitrogen atoms forming the carbamic acid (salt) structure in the oligoamine compound is 0.1% to 20% relative to the total nitrogen atoms in the oligoamine compound. When the proportion of the carbamic acid (salt) structure in the oligoamine compound (the proportion of nitrogen atoms forming the carbamic acid (salt) structure in the oligoamine compound) is less than 0.1%, the hydrophilicity of the oligoamine compound is insufficient. When it is supported on hydrophilic silica gel to form a solid absorbent material for carbon dioxide separation, the impregnating liquid has difficulty penetrating into the micropores or mesopores, making it difficult to retain the carbon dioxide separation composition within the micropores or mesopores, thus reducing the adsorption and desorption performance of carbon dioxide. When the proportion of the carbamic acid (salt) structure in the oligoamine compound (the proportion of nitrogen atoms forming the carbamic acid (salt) structure in the oligoamine compound) exceeds 20%, the number of amino groups that effectively play a role in the adsorption and desorption of carbon dioxide decreases, further reducing the adsorption and desorption performance of carbon dioxide. In the oligoamine compound, the proportion of nitrogen atoms forming the carbamic acid (salt) structure is preferably 0.2% to 18% relative to the total nitrogen atoms of the oligoamine compound, more preferably 0.3% to 15%, further preferably 0.4% to 10%, particularly preferably 0.5% to 8%, and most preferably 1% to 5%. According to one embodiment, the proportion of nitrogen atoms forming the carbamic acid or its salt structure in the oligoamine compound is 0.1% to 10%, 0.1% to 5%, 0.5% to 10%, 0.5% to 5%, 0.8% to 10%, 0.8% to 5%, 1% to 10%, 1% to 4%, or 1% to 3% relative to the total nitrogen atoms of the oligoamine compound.

[0065] By controlling the proportion of carbamate (salt) structures in the oligoamine compound (the proportion of nitrogen atoms forming carbamate (salt) structures in the oligoamine compound) within a certain range, the hydrophilicity and water retention capacity of the oligoamine compound are improved. Therefore, when using the carbon dioxide separation composition to separate carbon dioxide, even under low humidity driving conditions, the viscosity increase of the absorbent component can be suppressed, maintaining the adsorption and desorption performance of carbon dioxide. Furthermore, due to the increased affinity of the oligoamine compound to the surface of hydrophilic silica gel, when a solid absorbent material for carbon dioxide separation is prepared by supporting it on hydrophilic silica gel, the impregnating liquid easily penetrates into the micropores or mesopores, forming absorption sites that retain the carbon dioxide separation composition within the micropores or mesopores. A method for preparing oligoamine compounds in which a portion of the amino group is a carbamate (salt) structure is described below.

[0066] As a method to confirm the formation of carbamic acid (salt) structures in oligoamine compounds, one simply needs to dissolve the oligoamine compound or carbon dioxide separation composition in heavy water or the like, and then measure... 13 C-NMR spectroscopy confirms the presence of a signal (peak) around 160 ppm. Alternatively, the proportion of the carbamate (salt) structure relative to the total nitrogen atoms of the oligoamine compound can be determined by integrating the peak around 160 ppm and comparing its area with an internal standard or other carbon atoms. Furthermore, IR spectroscopy can also confirm the presence of a signal (peak) around 1600 cm⁻¹. -1 ~1550cm -1 Peaks originating from the carbamate (salt) structure appear nearby to determine the formation of the carbamate (salt) structure (Non-patent literature 6: Chenhu Sun et al., “Infrared Spectroscopic Study of Reaction of Carbon Dioxide with Aqueous Monoethanolamine Solutions”, Industrial & Engineering Chemistry Research 2016, Vol. 55, pp. 6276-6283).

[0067] In the carbon dioxide separation composition of this method, the oligoamine compound is preferably a compound with low vapor pressure that is not easily volatilized into the treated gas. The boiling point of the oligoamine compound is 200°C or higher at atmospheric pressure, preferably 300°C or higher, more preferably 350°C or higher, further preferably 400°C or higher, particularly preferably 450°C or higher, and most preferably has no boiling point. In practical applications, if the oligoamine compound has a boiling point, its boiling point is preferably below 1000°C at atmospheric pressure. The boiling point of the oligoamine compound can be determined by detecting the differential thermal peak generated by evaporation using differential calorimetry.

[0068] In the carbon dioxide separation composition of this method, the total amine value of the oligoamine compound is preferably 400 KOH mg / g to 1500 KOH mg / g, more preferably 600 KOH mg / g to 1400 KOH mg / g, even more preferably 800 KOH mg / g to 1350 KOH mg / g, and particularly preferably 900 KOH mg / g to 1300 KOH mg / g. Oligoamine compounds with such amine values ​​exhibit excellent reactivity with carbon dioxide, thus increasing the adsorption and desorption of carbon dioxide in solid absorbent materials supporting the carbon dioxide separation composition, which is advantageous from this perspective. The total amine value is expressed as the weight (mg) of potassium hydroxide equivalent required to neutralize 1 g of the sample, and can be determined, for example, by a method based on ASTM D2074. Furthermore, the carbamate (salt) structure of the oligoamine compound causes carbon dioxide to desorb during the determination of the total amine value, thus the nitrogen atoms forming the carbamate (salt) structure are calculated in the form of amines. Therefore, the total amine value of oligoamine compounds is the same for oligoamine compounds with carbamic acid (salt) structures and for the oligoamine compounds of the following raw materials.

[0069] In the carbon dioxide separation composition of this method, from the viewpoint of rapid reaction with carbon dioxide, the oligoamine compound preferably contains a primary amino group (primary amine structure). The proportion of primary amino groups among all the amino groups in the oligoamine compound (the proportion of primary amine structures among all the amine structures in the oligoamine compound) is preferably 5% or more, more preferably 10% to 70%, further preferably 12% to 60%, particularly preferably 15% to 50%, and most preferably 20% to 40%. The proportion of primary amino groups in the oligoamine compound (the proportion of primary amine structures in the oligoamine compound) can be determined by measurement... 13 C-NMR is used to determine the ratio by comparing the areas of the carbon atoms adjacent to the amine. Furthermore, the proportion of primary amines in the oligoamine compound described here refers to the proportion of primary amines in oligoamine compounds with an carbamic acid (salt) structure, which differs from the proportion of primary amines in the raw material (raw material oligoamine compound) of the oligoamine compound described below.

[0070] The number average molecular weight of the oligoamine compound is preferably 200 or more and less than 2000, more preferably 200 to 1500, even more preferably 200 to 1000, even more preferably 250 to 900, particularly preferably 280 to 800, and most preferably 300 to 700. According to one embodiment, the number average molecular weight of the oligoamine compound is 200 to 800, 300 to 900, 300 to 800, or 200 to 600. Oligoamine compounds with such a number average molecular weight are advantageous because they suppress both vapor pressure and viscosity, thus inhibiting volatility and increasing adsorption and desorption rates.

[0071] The number-average molecular weight of oligoamine compounds can be determined using a boiling point meter or similar method via the boiling point elevation method. In this method, a certain amount of solvent is taken and its boiling point is measured; then a trace amount of solute is dissolved in the solvent, and the boiling point of this solution is measured. Based on this, the following formula is used for calculation. Thus, the molar mass of the solute can be determined, and when the oligoamine compound is used as the solute, this molar mass can be taken as the number-average molecular weight. Solvents that can be used include methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, ethylene glycol monomethyl ether, ethylene glycol dimethyl ether, and diethylene glycol dimethyl ether.

[0072] ·Δtb=ΔKb×m

[0073] (Boiling point elevation: Δtb [K], molar boiling point elevation: ΔKb [K], solute molality: m [mol / kg])

[0074] ·m=w / M×1000 / W

[0075] (Solute molar concentration: m [mol / kg], solute mass: w [g], solute molar mass: M [g / mol], solvent mass: W [g]).

[0076] The molecular weight distribution (weight-average molecular weight (Mw) / number-average molecular weight (Mn)) of the oligoamine compound is, for example, 1 to 20, preferably 1 to 15, more preferably 1 to 10, and even more preferably 1 to 5.

[0077] Specific examples of oligoamine compounds include: polyethyleneimine, modified polyethyleneimine in which some primary amine groups are converted into secondary amine groups through the introduction of organic groups; diethylenetriamine, modified diethylenetriamine in which some primary amine groups are converted into secondary amine groups through the introduction of organic groups; triethylenetetramine, modified triethylenetetramine in which some primary amine groups are converted into secondary amine groups through the introduction of organic groups; tetraethylenepentamine, modified tetraethylenepentamine in which some primary amine groups are converted into secondary amine groups through the introduction of organic groups; and pentaethylenehexamine, modified pentaethylenehexamine in which some primary amine groups are converted into secondary amine groups through the introduction of organic groups. Modified pentaethylenehexamine, hexadecimaline heptaethylene, and a portion of the primary amine of hexadecimaline heptaethylene can be converted into secondary amines through the introduction of organic groups; modified hexadecimaline heptaethylene, heptaethylene octaethylene, and a portion of the primary amine of heptaethylene octaethylene can be converted into secondary amines through the introduction of organic groups; modified tri(2-aminoethyl)amine, and a portion of the primary amine of tri(2-aminoethyl)amine can be converted into secondary amines through the introduction of organic groups; modified tetra(2-aminoethyl)ethylenediamine, and a portion of the primary amine of tetra(2-aminoethyl)ethylenediamine can be converted into secondary amines through the introduction of organic groups; etc.

[0078] Among these, considering the low vapor pressure and low volatility in the treated gas, the preferred alternatives are: polyethyleneimine, modified polyethyleneimine in which a portion of the primary amine of polyethyleneimine is converted into a secondary amine through the introduction of organic groups; tetraethylenepentamine in which a portion of the primary amine is converted into a secondary amine through the introduction of organic groups; pentaethylenehexamine, modified pentaethylenehexamine in which a portion of the primary amine of pentaethylenehexamine is converted into a secondary amine through the introduction of organic groups; hexadecimaline, modified hexadecimaline heptaethylene, modified hexadecimaline heptaethylene, modified heptaethylene octaethylene, modified heptaethylene octaethylene, modified tri(2-aminoethyl)amine in which a portion of the primary amine is converted into a secondary amine through the introduction of organic groups; tetra(2-aminoethyl)ethylenediamine, modified tetra(2-aminoethyl)ethylenediamine in which a portion of the primary amine is converted into a secondary amine through the introduction of organic groups.

[0079] From the viewpoint of availability and low volatility, polyethyleneimine is the most preferred oligoamine compound. According to one embodiment, the oligoamine compound is polyethyleneimine with a number-average molecular weight of 200 or more and less than 2000 (preferably 200 to 1000). According to one embodiment, the carbon dioxide separation composition of this type comprises polyethyleneimine with a boiling point of 200°C or more and a number-average molecular weight of 200 or more and less than 2000 (preferably 200 to 1000), and a modifier with a boiling point of 200°C or more, wherein a portion of all nitrogen atoms in the polyethyleneimine has an carbamic acid structure or a salt thereof.

[0080] The oligoamine compound can be a commercially available product. Commercially available oligoamine compounds that do not have a carbamic acid (salt) structure can be formulated to form a carbamic acid (salt) structure by the following methods to produce the oligoamine compound used in the carbon dioxide separation composition of this method. Examples of oligoamine compounds that do not have a carbamic acid (salt) structure include SP-003, SP-006, SP-012, and SP-018, manufactured by Nippon Shokubai Co., Ltd., which are commercially available polyethyleneimine products.

[0081] Oligoamine compounds can be used alone or in combination of two or more.

[0082] The weight ratio of the oligoamine compound to the modifier (weight of oligoamine compound: weight of modifier) ​​is preferably 10:90 to 95:5, more preferably 12:88 to 90:10, even more preferably 15:85 to 85:15, particularly preferably 20:80 to 82:18, and most preferably 30:70 to 80:20. By including the oligoamine compound and the modifier within the above range, the adsorption and desorption capacity of carbon dioxide in the solid absorbent material supporting the carbon dioxide separation composition can be further increased.

[0083] The content of the oligoamine compound relative to the total weight of the non-volatile components of the carbon dioxide separation composition is preferably 30% to 99% by weight, more preferably 35% to 95% by weight, and even more preferably 40% to 90% by weight. According to one embodiment, the content of the oligoamine compound relative to the total weight of the non-volatile components of the carbon dioxide separation composition is 32% to 99% by weight, 32% to 98% by weight, 32% to 95% by weight, 33% to 92% by weight, 33% to 90% by weight, 35% to 92% by weight, 35% to 90% by weight, 35% to 85% by weight, or 35% to 80% by weight. According to one embodiment, the content of the oligoamine compound relative to the total weight of the non-volatile components of the carbon dioxide separation composition is 20% to 60% by weight, 40% to 60% by weight, 40% to 80% by weight, 50% to 80% by weight, or 60% to 80% by weight. By including oligoamine compounds within the aforementioned range, the adsorption and desorption capacity of carbon dioxide in the solid absorbent material supporting the carbon dioxide separation composition can be further increased. Furthermore, the non-volatile component of the carbon dioxide separation composition is the non-volatile component after drying at 120°C for 6 hours.

[0084] Here, in order to prepare a portion of the oligoamine compound with an amino group of carbamate (salt) structure, it is sufficient to contact the oligoamine compound used as a raw material (hereinafter referred to as the raw material oligoamine compound) with carbon dioxide. The carbon dioxide is not limited to a gas containing 100% carbon dioxide by volume; any gas containing carbon dioxide is acceptable. For example, air can be used as the gas containing carbon dioxide.

[0085] For example, to form an urethane (salt) structure in a raw material oligoamine compound, the raw material oligoamine compound can be contacted with carbon dioxide or a gas containing carbon dioxide (e.g., air) before being supported on a porous material or other carrier, or it can be contacted with carbon dioxide or a gas containing carbon dioxide (e.g., air) after the raw material oligoamine compound is supported on the porous material or other carrier. Specifically, carbon dioxide or a gas containing carbon dioxide (e.g., air) can be introduced into an impregnation liquid containing the raw material oligoamine compound and a modifier, or carbon dioxide or a gas containing carbon dioxide (e.g., air) can be introduced into the carrier supporting the impregnation liquid after the porous material or other carrier has been impregnated with an impregnation liquid containing the raw material oligoamine compound and a modifier. Alternatively, the porous material or other carrier can be impregnated with an impregnation liquid containing the raw material oligoamine compound and a modifier, and the impregnation liquid can be concentrated in air. As a concentration treatment, for example, a method using a rolling mixer, where water is evaporated while impregnation is being carried out.

[0086] Preferably, the raw material oligoamine compound is contacted with carbon dioxide or a gas containing carbon dioxide (e.g., air) at a temperature preferably 30–100°C, more preferably 40–98°C, further preferably 50–95°C, particularly preferably 50–90°C, and most preferably 55–85°C. The contact time between the raw material oligoamine compound and carbon dioxide or a gas containing carbon dioxide (e.g., air) is preferably 0.1 to 48 hours, more preferably 0.2 to 24 hours, further preferably 0.5 to 12 hours, particularly preferably 1 to 10 hours, and most preferably 2 to 8 hours. According to one embodiment, the contact time between the raw material oligoamine compound and carbon dioxide or a gas containing carbon dioxide (e.g., air) is 1 to 8 hours, 3 to 8 hours, 4 to 8 hours, or 2 to 10 hours. According to one embodiment, the raw material oligoamine compound is contacted with carbon dioxide or a gas containing carbon dioxide (e.g., air) at a temperature of 50°C to 95°C (or 55 to 90°C) for 0.5 to 12 hours (or 1 to 10 hours).

[0087] From the viewpoint of improving the solubility of the carbamate (salt) structure, the contact between the raw material oligoamine compound and carbon dioxide or a gas containing carbon dioxide (e.g., air) is preferably carried out in the presence of water. Therefore, it is preferable to contact the raw material oligoamine compound with carbon dioxide by impregnating a carrier such as a porous material with an impregnation solution containing the raw material oligoamine compound, a modifier, and water, and then introducing carbon dioxide or a gas containing carbon dioxide (e.g., air) into the carrier carrying the impregnation solution. By introducing carbon dioxide or a gas containing carbon dioxide (e.g., air) into the carrier carrying the impregnation solution, the carrier carrying the impregnation solution can be dried, thereby obtaining a solid absorbent material carrying a composition for carbon dioxide separation.

[0088] As described above, upon contact with carbon dioxide, some nitrogen atoms in the oligoamine compound form a carbamate (salt) structure. The total amine value of the raw material for such an oligoamine compound (raw material oligoamine compound) is preferably, for example, 400 KOH mg / g to 1500 KOH mg / g. More preferably, the total amine value of the raw material oligoamine compound is 600 KOH mg / g to 1400 KOH mg / g, even more preferably 800 KOH mg / g to 1350 KOH mg / g, and particularly preferably 900 KOH mg / g to 1300 KOH mg / g. If the raw material oligoamine compound has such an amine value, the adsorption and desorption capacity of carbon dioxide can be increased after the formation of the carbamate (salt) structure. The total amine value is expressed as the weight (mg) of potassium hydroxide equivalent required to neutralize 1 g of the sample, and can be determined, for example, by a method based on ASTM D2074.

[0089] Furthermore, from the perspective of rapid reaction with carbon dioxide, the primary amine structure is preferred as a raw material for the oligoamine compound. The raw material oligoamine compound is a compound having a primary amine structure in which 10% or more and 70% or less, more preferably 20% or more and 60% or less, and even more preferably 30% or more and 50% or less of the total amino groups. The proportion of primary amines in the raw material oligoamine compound (the proportion of primary amine structures in the oligoamine compound) can be determined by measurement. 13 C-NMR is used to determine the area of ​​the carbon atoms adjacent to the amine.

[0090] <Modifier>

[0091] As a modifier, an oligoamine compound or a compound capable of dissolving or dispersing the raw material oligoamine compound is preferred. Therefore, the modifier can also be called a solvent, and is therefore preferably a liquid at 25°C. In the carbon dioxide separation composition of this type, the modifier has a boiling point of 200°C or higher at atmospheric pressure. The boiling point of the modifier is preferably 250°C or higher, more preferably 300°C or higher, and even more preferably 350°C or higher. The modifier can be a compound without a boiling point. In practical applications, when the modifier has a boiling point, the boiling point of the modifier is preferably 1000°C or lower at atmospheric pressure. The boiling point of the modifier can be determined by detecting the differential thermal peak generated by evaporation using differential calorimetry.

[0092] The modifier is a compound that remains in a liquid state within the driving temperature range (0°C to 120°C) of the solid absorbent material for carbon dioxide separation. Preferably, it is a compound with low vapor pressure (i.e., a boiling point above 200°C) and low volatility into the treated gas. By using a modifier with these characteristics, evaporation of the carbon dioxide separation composition during driving can be suppressed, which is beneficial for application under a wide range of driving conditions.

[0093] The Hansen solubility parameters (HSP values) of the modifier are preferably, for example, ΔD = 12 or more and 22 or less, ΔP = 5 or more and 15 or less, and ΔH = 3 or more and 30 or less; more preferably ΔD = 14 or more and 20 or less, ΔP = 6 or more and 14 or less, and ΔH = 4 or more and 28 or less; even more preferably ΔD = 14.5 or more and 19 or less, ΔP = 6.5 or more and 13.5 or less, and ΔH = 5 or more and 25 or less; particularly preferably ΔD = 15 or more and 18 or less, ΔP = 7 or more and 13 or less, and ΔH = 12 or more and 22 or less. If the HSP value is within this range, then the oligoamine compound can be effectively dissolved or dispersed. Specific examples of HSP values ​​include: triethanolamine (ΔD: 17.3, ΔP: 7.6, ΔH: 21 / boiling point 335.4℃), triethylene glycol (ΔD: 16, ΔP: 12.5, ΔH: 18.6 / boiling point 285℃), 1,6-hexanediol (ΔD: 15.7, ΔP: 8.4, ΔH: 17.8 / boiling point 250℃), 1,9-nonanediol (ΔD: 15.7, ΔP: 7, ΔH: 15.1 / boiling point 288℃), and N-methylpyrrolidone (ΔD: 18, ΔP: 12.3, ΔH: 21 / boiling point 335.4℃). 7.2 (boiling point 202℃), dimethyl phthalate (ΔD: 18.6, ΔP: 10.8, ΔH: 4.9 / boiling point 284℃), catechol (ΔD: 20, ΔP: 11.3, ΔH: 21.8 / boiling point 245℃), diethylene glycol butyl methyl ether (ΔD: 15.89, ΔP: 4.75, ΔH: 5.61 / boiling point 215℃), tripropylene glycol dimethyl ether (ΔD: 15.83, ΔP: 6.35, ΔH: 4.82 / boiling point 215℃), 1,3-dimethyl-2-imidazolinone (ΔD: 18.01) (ΔP: 9.58, ΔH: 8.57 / boiling point 225℃), diethylene glycol monobutyl ether (ΔD: 16.29, ΔP: 6.18, ΔH: 10.46 / boiling point 230℃), triethylene glycol monomethyl ether (ΔD: 16.52, ΔP: 7.45, ΔH: 11.69 / boiling point 249℃), diethylene glycol dibutyl ether (ΔD: 15.85, ΔP: 3.98, ΔH: 4.68 / boiling point 256℃), triethylene glycol butyl methyl ether (ΔD: 15.95, ΔP: 4.85, ΔH: 5.89 / boiling point 261℃) Tetraethylene glycol dimethyl ether (ΔD: 16.08, ΔP: 5.69, ΔH: 6.98 / boiling point 275℃), adiponitrile (ΔD: 16.7, ΔP: 15.66, ΔH: 6.72 / boiling point 295℃), tetraethylene glycol (ΔD: 16.73, ΔP: 9.02, ΔH: 14.58 / boiling point 314℃), tricresyl phosphate (ΔD: 18.96, ΔP: 12.26, ΔH: 4.76 / boiling point 410℃), polyethylene glycol monomethyl ether 350 (ΔD: 15.97, ΔP: 6.46, ΔH: 9.23 (boiling point > 350℃), polyethylene glycol monomethyl ether 450 (ΔD: 15.73, ΔP: 6.26, ΔH: 8.84 / boiling point > 350℃), polyethylene glycol monomethyl ether 550 (ΔD: 15.46, ΔP: 6.08, ΔH: 8.62 / boiling point > 350℃), polyethylene glycol monomethyl ether 750 (ΔD: 15.21, ΔP: 5.95, ΔH: 8.71 / boiling point > 350℃), polyethylene glycol 200 (ΔD: 16.73, ΔP: 9.02, ΔH: 14.58 / ...750 (ΔD: 15.21, ΔP: 5.95, ΔH: 8.71 / boiling point > 350℃), polyethylene glycol 200 (ΔD: 16.73, ΔP: 9.02, ΔH: 14.58 / boiling point > 3 300℃ and below 350℃), polyethylene glycol 300 (ΔD: 16.24, ΔP: 8.15, ΔH: 11.8 / boiling point > 350℃), polyethylene glycol 400 (ΔD: 15.73, ΔP: 7.47, ΔH: 9.68 / boiling point > 350℃), polyethylene glycol 500 (ΔD: 15.49, ΔP: 7.2, ΔH: 8.9 / boiling point > 350℃), polyethylene glycol 600 (ΔD: 15.3, ΔP: 7.01, ΔH: 8.39 / boiling point > 350℃), polyethylene glycol 700 Polyethylene glycol 800 (ΔD: 14.99, ΔP: 6.87, ΔH: 7.78 / boiling point >350℃), Polyethylene glycol 1000 (ΔD: 14.85, ΔP: 6.58, ΔH: 7.67 / boiling point >350℃), Polyethylene glycol 1200 (ΔD: 14.75, ΔP: 6.47, ΔH: 7.78 / boiling point >350℃), Polypropylene glycol 400 (ΔD: 16.4, ΔP: 5.56) The following are some examples of polypropylene glycol (PPG) values: ΔD: 7.03 / boiling point >350℃, 600 (ΔD: 16.59, ΔP: 5.02, ΔH: 5.54 / boiling point >350℃), 800 (ΔD: 16.89, ΔP: 4.53, ΔH: 4.74 / boiling point >350℃), 1000 (ΔD: 17.4, ΔP: 3.9, ΔH: 4.21 / boiling point >350℃), and 1200 (ΔD: 17.84, ΔP: 3.4, ΔH: 4.03 / boiling point >350℃). The HSP value can be determined by the following... <1> - <3> The method described in the text is used to determine it.

[0094] HSP value calculation method

[0095] <1> Hansen, Charles(2007).Hansen Solubility Parameters:A user'shandbook, Second Edition.Boca Raton, Fla: CRC Press.

[0096] <2> Emmanuel Stefanis and Costas Panayiotou, Int J Thermophys(2008)29:568-585

[0097] <3> HSPiP: Hansen Solubility Parameter in Practice. http: / / www.hansen-solubility.com / .

[0098] Specific examples of modifiers include: N-methylpyrrolidone (202℃), diethylene glycol butyl methyl ether (215℃), tripropylene glycol dimethyl ether (215℃), 1,3-dimethyl-2-imidazolinone (225℃), diethylene glycol monobutyl ether (230℃), catechol (245℃), triethylene glycol monomethyl ether (249℃), 1,6-hexanediol (250℃), diethylene glycol dibutyl ether (256℃), triethylene glycol butyl methyl ether (261℃), tetraethylene glycol dimethyl ether (275℃), triethylene glycol (285℃), dimethyl phthalate (284℃), 1,9-nonanediol (288℃), adiponitrile (295℃), tetraethylene glycol (314℃), triethanolamine (335.4℃), and tricresyl phosphate (410℃). Polyethylene glycol monomethyl ether 350 (>350℃), polyethylene glycol monomethyl ether 450 (>350℃), polyethylene glycol monomethyl ether 550 (>350℃), polyethylene glycol monomethyl ether 750 (>350℃), polyethylene glycol 200 (above 300℃ but below 350℃), polyethylene glycol 300 (>350℃), polyethylene glycol 400 (>350℃), polyethylene glycol 5 00 (>350℃), polyethylene glycol 600 (>350℃), polyethylene glycol 800 (>200℃→>350℃), polyethylene glycol 1000 (boiling point>350℃), polyethylene glycol 1200 (boiling point>350℃), polyethylene glycol 2000 (boiling point>350℃), polyethylene glycol 3000 (boiling point>350℃), etc. (The boiling points of each substance are in parentheses).

[0099] As modifiers, preferred options include triethylene glycol monomethyl ether, triethylene glycol butyl methyl ether, tetraethylene glycol dimethyl ether, triethylene glycol, tetraethylene glycol, polyethylene glycol monomethyl ether (preferably polyethylene glycol monomethyl ether 350, polyethylene glycol monomethyl ether 450, polyethylene glycol monomethyl ether 550, polyethylene glycol monomethyl ether 750), and polyethylene glycol (preferably polyethylene glycol 200, polyethylene glycol 300, polyethylene glycol 400, polyethylene glycol 500, etc.). Substances with a polyethylene glycol structure, such as polyethylene glycol 600 and polyethylene glycol 800, are preferred, with polyethylene glycol monomethyl ether and / or polyethylene glycol being more preferred. Particularly preferred are polyethylene glycol monomethyl ether 350, polyethylene glycol monomethyl ether 450, polyethylene glycol monomethyl ether 550, polyethylene glycol monomethyl ether 750, polyethylene glycol 200, polyethylene glycol 300, polyethylene glycol 400, polyethylene glycol 500, polyethylene glycol 600, and polyethylene glycol 800.

[0100] According to one embodiment, the modifier is a compound having a polyethylene glycol structure. By having a polyethylene glycol structure as the modifier, the adsorption and desorption capacity of carbon dioxide can be further increased in the solid absorbent material supporting the carbon dioxide separation composition. The number-average molecular weight of the polyethylene glycol-structured compound used as the modifier is preferably 200–3000, more preferably 200–2500, even more preferably 200–2000, even more preferably 200–1500, particularly preferably 280–1200, and most preferably 300–1000. According to one embodiment, the number-average molecular weight of the polyethylene glycol-structured compound used as the modifier is 200–1000, 300–800, 300–700, 300–600, or 200–600. By having a number-average molecular weight within the above range, the oligoamine compound can be more effectively supported on the carrier, and the adsorption and desorption capacity of carbon dioxide can be further increased in the solid absorbent material supporting the carbon dioxide separation composition.

[0101] The number-average molecular weight of compounds with a polyethylene glycol (PEG) structure can be determined using a boiling point meter or similar instrument via the boiling point elevation method. In this method, a certain amount of solvent is used to determine its boiling point; then a trace amount of solute is dissolved in the solvent, and the boiling point of this solution is also determined. Based on this, the following formula is used for calculation. This allows the determination of the molar mass of the solute, which can be used as the number-average molecular weight when a PEG-structured compound is used as the solute. Suitable solvents include methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, ethylene glycol monomethyl ether, ethylene glycol dimethyl ether, and diethylene glycol dimethyl ether.

[0102] According to one embodiment, the carbon dioxide separation composition of this type comprises polyethyleneimine as an oligoamine compound and a compound having a polyethylene glycol structure as a modifier. This allows the oligoamine compound to be more effectively supported on the carrier, further increasing the adsorption and desorption capacity of carbon dioxide in the solid absorbent material supporting the carbon dioxide separation composition. Furthermore, according to another embodiment, the carbon dioxide separation composition of this type comprises polyethyleneimine as an oligoamine compound with a number average molecular weight of 200 or more and less than 2000 (preferably 200 to 1000), and a compound having a polyethylene glycol structure as a modifier with a number average molecular weight of 200 or more and less than 3000 (preferably 200 to 1000). This improves the support of the aforementioned oligoamine compound on the carrier, further increasing the adsorption and desorption capacity of carbon dioxide in the solid absorbent material supporting the carbon dioxide separation composition.

[0103] Another specific example of a modifier is an ionic liquid. Ionic liquids are not particularly limited; for example, they can be combinations of cations such as imidazolium, pyridinium, pyrrolidineonium, piperidinium, ammonium, and phosphonium, with anions such as halide ions, tetrafluoroborate, hexafluorophosphate, and bis(trifluoromethanesulfonyl)amide. Considering high affinity for oligoamine compounds, combinations of cations with relatively small organic groups (less than 13 carbon atoms), such as dialkylimidazolium, alkylpyridinium, tetraalkylammonium, and tetraalkylphosphonium, with anions such as lactate, carboxylic acid anions, trifluoromethanesulfonate, and methanesulfonate are preferred.

[0104] Modifiers can be used alone or in combination of two or more.

[0105] The content of the modifier relative to the total weight of the non-volatile components of the carbon dioxide separation composition is preferably 1% to 80% by weight, more preferably 5% to 75% by weight, and even more preferably 10% to 70% by weight. According to one embodiment, the content of the modifier relative to the total weight of the non-volatile components of the carbon dioxide separation composition is 5% to 70% by weight, 15% to 70% by weight, 15% to 65% by weight, 15% to 60% by weight, 20% to 70% by weight, 20% to 65% by weight, or 20% to 60% by weight. By including the modifier within the above range, the adsorption and desorption capacity of carbon dioxide can be further increased in the solid absorbent material supporting the carbon dioxide separation composition. Furthermore, the non-volatile components of the carbon dioxide separation composition are those that remain after drying at 120°C for 6 hours.

[0106] According to one embodiment, the content of the modifier relative to the total weight of the non-volatile components of the carbon dioxide separation composition is preferably 6% to 70% by weight, more preferably 8% to 65% by weight, and even more preferably 10% to 60% by weight. According to one embodiment, the content of the modifier relative to the total weight of the non-volatile components of the carbon dioxide separation composition is 20% to 50% by weight, 30% to 60% by weight, 40% to 60% by weight, or 20% to 40% by weight.

[0107] <Water>

[0108] The carbon dioxide separation composition of this method preferably contains water. By including water in the carbon dioxide separation composition, it is easier to mix and / or dissolve the oligoamine compound with the modifier, and it is possible to suppress the precipitation of carbamate (salt) of the oligoamine compound generated during carbon dioxide absorption.

[0109] There is no limitation on the water content within the range that maintains the carbon dioxide absorption performance. The water content in the carbon dioxide separation composition is preferably 1% to 30% by weight, more preferably 1.5% to 29% by weight, further preferably 2% to 28% by weight, particularly preferably 2.5% to 27% by weight, and most preferably 3% to 26% by weight relative to the total weight of the carbon dioxide separation composition. According to one embodiment, the water content in the carbon dioxide separation composition relative to the total weight of the carbon dioxide separation composition is 0.1 wt% to 5 wt%, 0.1 wt% to 10 wt%, 1 wt% to 20 wt%, 0.1 wt% to 25 wt%, 0.1 wt% to 20 wt%, 0.1 wt% to 30 wt%, 0.5 wt% to 10 wt%, 0.5 wt% to 20 wt%, 0.5 wt% to 25 wt%, 0.5 wt% to 20 wt%, 0.5 wt% to 30 wt%, 1 wt% to 20 wt%, 1 wt% to 15 wt%, 1 wt% to 10 wt%, 1 wt% to 5 wt%, 5 wt% to 30 wt%, 5 wt% to 25 wt%, 5 wt% to 15 wt%, 5 wt% to 10 wt%, 8 wt% to 30 wt%, 8 wt% to 25 wt%, 8 wt% to 20 wt%, or 8 wt% to 15 wt%. If the water content is within the above range, it makes it easier to mix and / or dissolve the oligoamine compound with the modifier, and it can suppress the precipitation of carbamate (salt) of the oligoamine compound generated when absorbing carbon dioxide.

[0110] Solvents other than water

[0111] The composition for carbon dioxide separation may further include a solvent other than water. This can facilitate the mixing and / or dissolution of the oligoamine compound and the modifier. The solvent other than water is a component with a molecular weight less than 500 that is liquid at room temperature (25°C), excluding the oligoamine compound, the modifier, and water. Examples of solvents other than water include: methanol, ethanol, isopropanol, butanol, acetone, methyl ethyl ketone, acetonitrile, N,N-dimethylformamide, dimethyl sulfoxide, ethylene glycol, methyl cellosolve (ethylene glycol monomethyl ether), tetrahydrofuran, etc. One of the above solvents other than water may be used alone, or two or more may be used in combination. Among these, acetonitrile, N,N-dimethylformamide, dimethyl sulfoxide, and ethylene glycol are preferred solvents other than water, with acetonitrile being more preferred.

[0112] The content of solvents other than water in the carbon dioxide separation composition is not limited within the range that maintains the carbon dioxide absorption performance. It is preferably 0.01 wt% to 20 wt%, more preferably 0.01 wt% to 10 wt%, and even more preferably 0.01 wt% to 5 wt% relative to the total weight of the carbon dioxide separation composition. According to one embodiment, the content of solvents other than water in the carbon dioxide separation composition is 0.01 wt% to 3 wt%, 0.01 wt% to 2 wt%, or 0.01 wt% to 1 wt% relative to the total weight of the carbon dioxide separation composition.

[0113] <Other Ingredients>

[0114] The carbon dioxide separation composition may further include any components other than the aforementioned oligoamine compounds and modifiers, provided that the effects of this invention are achieved. Such arbitrary components and their proportions can be appropriately selected according to the intended purpose, etc.

[0115] As any component selected according to purpose, etc., examples include surfactants, antioxidants, crystallization inhibitors, etc.

[0116] Nonionic surfactants, anionic surfactants, cationic surfactants, and amphoteric surfactants can be used as surfactants. Surfactants with an HLB (hydrophilic-lipophilic balance) of 10 or more can be used, preferably 12 or more, more preferably 15 or more (the upper limit is, for example, 20 or less).

[0117] As antioxidants, free radical scavengers, peroxide decomposers, and metal passivators can be used. As free radical scavengers, phenolic antioxidants and amine antioxidants can be used, with amine antioxidants being preferred. As peroxide decomposers, there are no particular limitations as long as the substance can effectively decompose peroxides; sulfur-based antioxidants and phosphorus-based antioxidants can be used. As metal passivators, there are no particular limitations as long as the substance can effectively chelate and coordinate with transition metals such as copper, iron, chromium, and nickel; ethylenediaminetetraacetic acid (EDTA) and the like can be used effectively.

[0118] Examples of water-soluble polymers that can be used as crystallization inhibitors include polyvinylpyrrolidone, polyvinyl alcohol, and hydroxyethyl cellulose. By using water-soluble polymers as crystallization inhibitors, it is possible to inhibit the secondary interaction between the carbamic acid (salt) produced by the reaction of oligoamine compounds with carbon dioxide and the oligoamine compounds, thus preventing the formation of insoluble salts.

[0119] Any component may be included within a range that does not impair the performance of the composition for carbon dioxide separation, for example, preferably 0.01% to 30% by weight, more preferably 0.1% to 20% by weight, and even more preferably 0.5% to 10% by weight, relative to the composition for carbon dioxide separation.

[0120] Each ingredient can be used alone or in combination with two or more ingredients.

[0121] <Preparation Method>

[0122] The composition for carbon dioxide separation can be prepared by mixing an oligoamine compound (raw material oligoamine compound), a modifier, and any other components at a temperature condition where a liquid mixture can be obtained, for example, 20°C to 100°C. According to one embodiment, the composition for carbon dioxide separation can be prepared by mixing an oligoamine compound (raw material oligoamine compound), a modifier, water, and any other components at a temperature condition of 20°C to 100°C.

[0123] At this point, the oligoamine compound can use a compound with a pre-existing carbamate (salt) structure as a raw material. The oligoamine compound can be used in the preparation of a carbon dioxide separation composition by contacting carbon dioxide with a raw material that does not have a carbamate (salt) structure, for example, in the preparation of an impregnation solution containing the raw material oligoamine compound, a modifier, water (if necessary), and any other components, to convert a portion of the nitrogen atoms into a carbamate (salt) structure. In this case, the following hydrophilic silica gel can be used to contain an impregnation solution containing the raw material oligoamine compound, a modifier, water, and any other components. When the water in the impregnation solution held in the pores evaporates, it comes into contact with carbon dioxide, converting a portion of the nitrogen atoms into a carbamate (salt) structure. The contact conditions between the raw material oligoamine compound and carbon dioxide are as described above.

[0124] According to one embodiment, a carbon dioxide separation composition is prepared by preparing an impregnation liquid containing an oligoamine compound (raw oligoamine compound), a modifier, water, and any other components at a temperature of 20°C to 100°C, loading the impregnation liquid onto a carrier, and drying the carrier impregnated with the impregnation liquid to prepare a carrier (solid absorbent material) carrying the carbon dioxide separation composition.

[0125] B. Solid Absorbent Materials for Carbon Dioxide Separation

[0126] The carbon dioxide separation composition described in item A can be applied to a solid absorbent material for separating carbon dioxide from a gas containing carbon dioxide. This type of carbon dioxide separation composition can be used supported on a carrier. That is, according to the present invention, a solid absorbent material for carbon dioxide separation, formed by supporting the carbon dioxide separation composition of this type on a porous material (e.g., hydrophilic silica gel), is also provided. The solid absorbent material for carbon dioxide separation is formed comprising a porous material (e.g., hydrophilic silica gel) and the carbon dioxide separation composition supported on the hydrophilic silica gel.

[0127] <Porous Materials>

[0128] Porous materials are preferred as the carrier. Silica gel (both hydrophilic and hydrophobic silica gels) is preferred, with hydrophilic silica gel being more preferred. Any type of hydrophilic silica gel can be used. Hydrophilic silica gel has pores classified as micropores, mesopores, and macropores. The inner surface of the hydrophilic silica gel can effectively retain the carbon dioxide separation composition and water of this method. Furthermore, from a generality point of view, hydrophilic silica gel manufactured by the gelation method is preferred. Hydrophilic silica gel is generally obtained by drying and pulverizing silica gel synthesized from sodium silicate and inorganic acids. For example, commercially available products such as MIZUKASIL (registered trademark) manufactured by Mizusawa Chemical Industry Co., Ltd., or SYLYSIA (registered trademark) manufactured by Fuji Silicon Chemical Co., Ltd., can be used. In addition, hydrophilic silica gel can be molded into desired shapes using adhesives or the like.

[0129] The pore volume of porous materials (such as hydrophilic silica gel) is preferably 0.6 cm³. 3 / g~3.0cm 3 / g, more preferably 0.7cm 3 / g~2.5cm 3 / g, further optimized to 0.8cm 3 / g~2.0cm 3 / g, with a particularly preferred 0.9cm 3 / g~2.0cm 3 / g, optimal value 1.0cm 3 / g~1.8cm 3 / g.

[0130] If the pore volume of the porous material (e.g., hydrophilic silica gel) is within the above range, it can support a carbon dioxide separation composition that can perform adequately, and the mechanical strength of the porous material (e.g., hydrophilic silica gel) can also be sufficiently ensured.

[0131] The average pore size of porous materials (such as hydrophilic silica gel) is preferably 5 nm to 80 nm, more preferably 10 nm to 60 nm, even more preferably 12 nm to 55 nm, particularly preferably 12 nm to 50 nm, and most preferably 15 nm to 40 nm.

[0132] The specific surface area of ​​porous materials (such as hydrophilic silica gel) is preferably 70 m². 2 / g~800m 2 / g, more preferably 80m 2 / g~650m 2 / g, further optimized to 100m 2 / g~500m 2 / g, with a particularly high selection of 100m 2 / g~450m 2 / g, optimal value 100m 2 / g~400m 2 / g.

[0133] The bulk density (specific gravity) of porous materials (such as hydrophilic silica gel) is preferably 0.10 g / cm³. 3 Above and 0.7g / cm 3 Below, 0.15 g / cm³ is more preferred. 3 Above and 0.6 g / cm 3 The following is a further preferred value of 0.20 g / cm³. 3 Above and 0.5g / cm 3 The following applies. The internal surface of the pores in porous materials (e.g., hydrophilic silica gel) is preferably hydrophilic. In this specification, the water adsorption capacity per unit surface area, calculated by the following method, is 0.00002 g / m². 2 The above porous materials are considered hydrophilic porous materials. For example, the water adsorption capacity per unit surface area calculated by the following method is 0.00002 g / m². 2 The above-mentioned silicone is a hydrophilic silicone.

[0134] <Evaluation of hydrophilicity of the pore surface: Determination of moisture adsorption in low-humidity nitrogen>

[0135] Using TG-DTA (TG-DTA8120 and 8122 manufactured by Rigaku Corporation), the weight increase of porous materials heated to 130°C and dried was measured by cooling them to 40°C under the condition that the absolute humidity of the supplied gas was 1 g / kg.

[0136] The weight of the porous material during water adsorption and the weight of the porous material during drying are measured by TG-DTA. The amount of water adsorbed per unit surface area is calculated by the following formula.

[0137] [Evaluation of hydrophilicity of the inner surface of the pore]

[0138] Water adsorption capacity per unit surface area (g / m²) 2 = (Weight of porous material during water adsorption (mg) - Weight of porous material during drying (mg)) ÷ Weight of porous material during drying (mg) ÷ Specific surface area of ​​porous material (m²) 2 / g).

[0139] According to one embodiment, in the solid absorbent material for carbon dioxide separation, the hydrophilic silica gel has physical properties that satisfy one or more of the following (i) to (iv):

[0140] (i) The pore volume is 0.6 cm 3 / g~3.0cm 3 / g;

[0141] (ii) The average pore size is 5 nm to 80 nm;

[0142] (iii) Specific surface area is 70m² 2 / g~800m 2 / g;

[0143] (iv) Specific gravity is 0.10 g / cm³ 3 above.

[0144] By using hydrophilic silica gel selected from one or more of the group consisting of (i) to (iv) above, the adsorption and desorption of carbon dioxide can be further increased in a solid absorbent material carrying a carbon dioxide separation composition.

[0145] The shape of the hydrophilic silica gel can be arbitrarily selected according to the adsorption-desorption system. When used as a fluidized bed, powder is preferred; when used as a mobile phase, spherical shape is preferred; and when used as a stationary phase, granular or annular shape is preferred. Especially in stationary phases requiring large air volumes, it is preferable to process it into a honeycomb or filter-like molded body that can achieve low pressure loss.

[0146] The loading of non-volatile components of the carbon dioxide separation composition on a porous material (e.g., hydrophilic silica gel) is not limited as long as the effects of the present invention are achieved. For example, relative to the total weight of non-volatile components in the solid absorbent material for carbon dioxide separation, it is 20% to 80% by weight, preferably 25% to 75% by weight, more preferably 30% to 70% by weight, further preferably 35% to 65% by weight, particularly preferably 35% to 60% by weight, and most preferably 35% to 58% by weight. The loading of non-volatile components of the carbon dioxide separation composition on hydrophilic silica gel can be calculated by the following method.

[0147] <Calculation of the loading of non-volatile components in porous materials based on thermogravimetric analysis>

[0148] To determine the loading of non-volatile components in the composition for carbon dioxide separation, thermogravimetric analysis was performed using a TG-DTA (TG-DTA8120 or 8122 manufactured by Rigaku Corporation) with compressed air supplied to the TG-DTA oven at a rate of 200 ml / min using a mass flow controller.

[0149] The weight of non-volatile components of the solid absorbent material in a state where carbon dioxide and water are completely separated was determined by thermogravimetric analysis after treatment at 120°C for 1 hour. The total weight of non-volatile components of the carbon dioxide separation composition and the porous material was then calculated. The weight of non-volatile components of the solid absorbent material in a state where organic components are completely oxidized and decomposed was determined after treatment at 500°C for 1 hour. The weight of non-volatile components of the porous material was then calculated.

[0150] The non-volatile component loading ratio (parts by weight) of the carbon dioxide separation composition = (total non-volatile component weight (g) of the carbon dioxide separation composition and the porous material - non-volatile component weight (g) of the porous material) ÷ ​​total non-volatile component weight (g) of the carbon dioxide separation composition and the porous material × 100.

[0151] The water content in the solid absorbent material for carbon dioxide separation is not limited within a range that maintains the carbon dioxide absorption performance. The water content in the solid absorbent material for carbon dioxide separation is preferably 0.1% to 20% by weight, more preferably 0.2% to 18% by weight, further preferably 0.5% to 15% by weight, particularly preferably 1% to 12% by weight, and most preferably 4% to 12% by weight relative to the total weight of the solid absorbent material. According to one embodiment, the water content in the solid absorbent material for carbon dioxide separation is 0.1% to 5% by weight, 0.1% to 10% by weight, 1% to 10% by weight, 1% to 20% by weight, 2% to 15% by weight, 3% to 15% by weight, or 3% to 12% by weight relative to the total weight of the solid absorbent material. If the water content is within the above range, the mixing and / or dissolution of the oligoamine compound and the modifier becomes easier, and the precipitation of carbamate (salt) of the oligoamine compound generated during carbon dioxide absorption can be suppressed.

[0152] <Driving Methods for Solid Absorbent Materials in Carbon Dioxide Separation>

[0153] There are no particular limitations on the adsorption and desorption methods of carbon dioxide as a solid absorbent material for carbon dioxide separation. Examples include: using temperature swing, using pressure swing, using depressurization regeneration, using steam regeneration, and using a combination of these methods.

[0154] As an example, solid absorbent materials for carbon dioxide separation absorb carbon dioxide by contacting a supply gas containing carbon dioxide at a temperature of 0°C to 80°C. The released carbon dioxide is recovered by heating the treated gas to 60°C to 120°C after discharge. By switching the flow paths of the supply gas and the recovered gas, carbon dioxide can be separated and recovered.

[0155] As an example, solid absorbent materials for carbon dioxide separation absorb carbon dioxide by contacting a supply gas containing carbon dioxide at 0°C to 80°C under pressure. The released carbon dioxide is recovered by heating the treated gas to 60°C to 120°C after discharge. By switching the flow paths of the supply gas and the recovered gas, carbon dioxide can be separated and recovered.

[0156] As an example, a solid absorbent material for carbon dioxide separation absorbs carbon dioxide by contacting it with a supply gas containing carbon dioxide at 0°C to 80°C, and recovers the released carbon dioxide by reducing the pressure to 1 kPa to 20 kPa at 40°C to 80°C. By switching the flow paths of the supply gas and the recovered gas, carbon dioxide can be separated and recovered.

[0157] As an example, a solid absorbent material for carbon dioxide separation absorbs carbon dioxide by contacting it with a supply gas containing carbon dioxide at 0°C to 80°C, and recovers the released carbon dioxide by supplying steam at 20 kPa to 100 kPa at 60°C to 100°C. By switching the flow paths of the supply gas and the recovered gas, carbon dioxide can be separated and recovered.

[0158] Regarding solid absorbent materials for carbon dioxide separation, in a carbon dioxide adsorption-desorption test using solid absorbent materials with a carbon dioxide concentration of 300 to 500 ppm (e.g., 400 ppm) and an absolute humidity of 2 g / kg or less (e.g., 1 g / kg or more and 2 g / kg or less), the performance of the solid absorbent material in releasing carbon dioxide absorbed at 40°C at 70°C is as follows: the amount of carbon dioxide adsorbed and desorbed per gram of solid absorbent material is 0.90 mmol or more (preferably 1.0 mol or more, more preferably 1.1 mol or more), and the amount of carbon dioxide adsorbed and desorbed per mole of amine contained in the solid absorbent material is 0.20 mol or more (preferably 0.21 mol or more, more preferably 0.22 mol or more).

[0159] Regarding solid absorbent materials for carbon dioxide separation, in carbon dioxide adsorption-desorption tests using solid absorbent materials with a carbon dioxide concentration of 9000 to 11000 ppm (e.g., 10000 ppm) and an absolute humidity of 2 g / kg or less (e.g., 1 g / kg or more and 2 g / kg or less), the performance of the solid absorbent material in releasing carbon dioxide absorbed at 70°C at 100°C is as follows: the amount of carbon dioxide adsorbed and desorbed per gram of solid absorbent material is 1.30 mmol or more (preferably 1.40 mol or more, more preferably 1.50 mol or more), and the amount of carbon dioxide adsorbed and desorbed per mole of amine contained in the solid absorbent material is 0.20 mol or more (preferably 0.22 mol or more, more preferably 0.24 mol or more). These adsorption-desorption tests can be carried out by the following methods.

[0160] <Carbon dioxide adsorption-desorption experiment using carbon dioxide-containing gas in simulated dry atmosphere>

[0161] To determine the absorption and desorption of carbon dioxide, a TG-DTA (Rigaku Corporation TG-DTA8120, 8122) was used, and the weight was measured at the absorption temperature (40°C) and desorption temperature (70°C). Using a mass flow controller, a carbon dioxide-containing gas with adjusted nitrogen and carbon dioxide flow rates was supplied to the TG-DTA oven at a rate of 200 ml / min. The process was conducted under constant conditions with a simulated carbon dioxide concentration of approximately 400 ppm by volume and a supply gas humidity of 2 g / kg absolute humidity.

[0162] Based on TG-DTA measurements, the weight of the solid absorbent material during carbon dioxide absorption at various temperatures and the weight of the solid absorbent material during carbon dioxide desorption under heating were measured. The carbon dioxide adsorption / desorption amount and amine efficiency were then calculated using the following formula.

[0163] [Carbon dioxide adsorption and desorption capacity]

[0164] Carbon dioxide adsorption / desorption capacity (mmol / g)

[0165] = (Weight of solid absorbent material after carbon dioxide absorption (g) - Weight of solid absorbent material after carbon dioxide desorption (g)) ÷ Molecular weight of carbon dioxide (g / mmol) ÷ Weight of solid absorbent material (g)

[0166] [Amine efficiency]

[0167] Amine efficiency (mol / mol)

[0168] = Carbon dioxide adsorption / desorption capacity (mmol / g) / Number of amine moles per gram of solid absorbent material (mmol / g).

[0169] <Carbon dioxide adsorption-desorption experiment using carbon dioxide-containing gas in a simulated dry enclosed space>

[0170] To determine the absorption and desorption of carbon dioxide, a TG-DTA (Rigaku Corporation TG-DTA 8120, 8122) was used, and the weight was measured at the absorption temperature (70°C) and desorption temperature (100°C). Using a mass flow controller, the supply rates of nitrogen and carbon dioxide were adjusted to achieve a carbon dioxide concentration of approximately 10,000 ppm by volume, and the gas was supplied to the TG-DTA oven at a combined flow rate of 200 ml / min. Furthermore, the process was conducted at a constant humidity of 2 g / kg absolute humidity for the supplied gas.

[0171] The weight of the solid absorbent material during carbon dioxide absorption at various temperatures was determined by TG-DTA, and the weight of the solid absorbent material during carbon dioxide desorption under heating was calculated in the same manner as in carbon dioxide adsorption-desorption experiments using carbon dioxide-containing gas in simulated dry atmospheres, to determine the amount of carbon dioxide adsorption and desorption.

[0172] According to one embodiment, the solid absorbent material for carbon dioxide separation is selected from one or more of the group consisting of (i) and (ii) below;

[0173] (i) In the carbon dioxide adsorption-desorption test using air with a carbon dioxide concentration of 300 to 500 ppm (e.g., 400 ppm) and an absolute humidity of 2 g / kg or less, in the process of releasing the carbon dioxide absorbed by the above-mentioned solid absorbent material at 40°C at 70°C, the amount of carbon dioxide adsorbed and desorbed per gram of solid absorbent material is 0.9 mmol or more, and the amount of carbon dioxide adsorbed and desorbed per mole of amine contained in the solid absorbent material is 0.2 mol or more.

[0174] (ii) In the carbon dioxide adsorption-desorption test using air with a carbon dioxide concentration of 9000 to 11000 ppm (e.g., 10000 ppm) and an absolute humidity of 2 g / kg or less, in the process of releasing the carbon dioxide absorbed by the above-mentioned solid absorbent material at 70°C at 100°C, the amount of carbon dioxide adsorbed and desorbed per gram of solid absorbent material is 1.3 mmol or more, and the amount of carbon dioxide adsorbed and desorbed per mole of amine contained in the solid absorbent material is 0.2 mol or more.

[0175] By selecting one or more of the solid absorbent materials for carbon dioxide separation from the group consisting of (i) and (ii) above, the adsorption and desorption of carbon dioxide can be further increased in the solid absorbent material carrying the composition for carbon dioxide separation.

[0176] C. Manufacturing Method of Solid Absorbent Material for Carbon Dioxide Separation

[0177] The solid absorbent material for carbon dioxide separation described in item B can be obtained by fixing the carbon dioxide separation composition in the pores of silica gel through the following steps: (1) a first step of preparing an impregnation liquid containing an oligoamine compound with a boiling point of 200°C or higher, a modifier with a boiling point of 200°C or higher, and water; (2) a second step of impregnating the hydrophilic silica gel in the impregnation liquid; (3) a third step of separating the hydrophilic silica gel impregnated with the impregnation liquid from excess impregnation liquid; and (4) a fourth step of drying the hydrophilic silica gel impregnated with the impregnation liquid by evaporating water in an atmosphere containing carbon dioxide.

[0178] By loading the carbon dioxide separation composition onto hydrophilic silica gel using the method described above, the oligoamine component can be uniformly distributed in the micropores and mesopores within the pores of the hydrophilic silica gel, while maintaining the macropores required for gas diffusion. Therefore, it is possible to produce a solid absorbent material with a high carbon dioxide adsorption and desorption capacity per mole of amine.

[0179] In another example of a method for manufacturing a solid absorbent material for carbon dioxide separation, a mixture comprising an oligoamine compound with a boiling point of 200°C or higher and a modifier with a boiling point of 200°C or higher can be prepared, diluted in water to form an impregnation solution. This solution is then impregnated onto a porous material (hydrophilic silica gel), and the water is evaporated, forming a carbon dioxide separation composition within the pores of the hydrophilic silica gel. As yet another example, all components can be mixed together to prepare an impregnation solution, which is then impregnated onto hydrophilic silica gel. The water is then evaporated, forming carbon dioxide absorption sites within the pores of the hydrophilic silica gel.

[0180] (1) The first step of preparing an impregnation solution containing an oligoamine compound with a boiling point above 200°C, a modifier with a boiling point above 200°C, and water.

[0181] <Oligoamine compounds, modifiers>

[0182] The oligoamine compound (raw oligoamine compound) and / or modifier may be the substances described in "A. Compositions for Carbon Dioxide Separation".

[0183] <Water>

[0184] In the process of preparing the impregnation solution, water is used as a solvent from the viewpoints of viscosity reduction and safety. The amount of water added is preferably 0.1 to 9 times the total weight of the oligoamine compound and the modifier. More preferably, it is 0.2 to 7 times, further preferably 0.3 to 5 times, and most preferably 0.4 to 4 times the total weight of the oligoamine compound and the modifier. By using water as a solvent in the manufacture of the solid absorbent material for carbon dioxide separation, the hydrophilicity of the carbon dioxide separation composition is improved, and the carbon dioxide separation composition can be effectively supported in the micropores and mesopores of the hydrophilic silica gel. Furthermore, by using water as a solvent in the manufacture of the solid absorbent material for carbon dioxide separation, water remains in the supported carbon dioxide separation composition, which can suppress the precipitation of carbamate from the oligoamine compound during carbon dioxide absorption.

[0185] Solvents other than water

[0186] The impregnation solution may contain solvents other than water. By using solvents other than water, the solubility and viscosity of the composition for carbon dioxide separation can be adjusted.

[0187] Solvents other than water can be any solvent that can be mixed with water, the raw material oligoamine compound, and the modifier. For example, solvents other than water that may be contained in the above-mentioned carbon dioxide separation composition are also applicable. As solvents other than water, acetonitrile, ethylene glycol, N,N-dimethylformamide, and dimethyl sulfoxide are preferred. Acetonitrile is more preferred considering its ease of mixing with the oligoamine compound, modifier, and / or water, as well as its ease of removal in subsequent processes.

[0188] Solvents other than water can be used in combination of two or more, including oligoamine compounds, modifiers and water, and they can be mixed in any order.

[0189] The content of solvents other than water is preferably 1 to 200 parts by weight, more preferably 10 to 100 parts by weight, relative to 100 parts by weight of water.

[0190] The oligoamine compound used to prepare the impregnation solution may contain a carbamic acid (salt) structure. When using an oligoamine compound without a carbamic acid (salt) structure as a raw material, the oligoamine compound can be made into an oligoamine compound with a carbamic acid (salt) structure through the fourth step described in (4) below. Alternatively, when using an oligoamine compound without a carbamic acid (salt) structure as a raw material, it can be contacted with a gas containing carbon dioxide during the preparation of the impregnation solution to form a carbamic acid (salt) structure.

[0191] (2) The second step of immersing hydrophilic silica gel in an impregnation solution

[0192] In order to contain the impregnation solution prepared in the first step of (1) within the pores of the hydrophilic silica gel, any method can be used, such as impregnation, impregnation, liquid flow and other known methods.

[0193] Specifically, the hydrophilic silica gel can be impregnated in the impregnation solution prepared in the first step of (1), or the impregnation solution can be added to the hydrophilic silica gel by dripping or the like, or the impregnation solution can be passed through the container such as a column after the hydrophilic silica gel is filled.

[0194] At this point, considering the ease of operation and equipment, the immersion method is preferred.

[0195] The processing pressure can be arbitrarily selected as atmospheric pressure or reduced pressure. To remove air bubbles from the pores of the hydrophilic silica gel and allow the impregnation solution to penetrate efficiently, processing under reduced pressure is preferred. Specifically, the processing pressure is preferably -0.08 MPaG to -0.004 MPaG, more preferably -0.07 MPaG to -0.01 MPaG, and even more preferably -0.06 MPaG to -0.02 MPaG. According to one embodiment, the process of impregnating the hydrophilic silica gel in the impregnation solution includes a step of degassing the porous material under reduced pressure of -0.08 MPaG to -0.004 MPaG.

[0196] The process of immersing hydrophilic silica gel in an impregnation solution is preferably carried out in a temperature range of 20°C to 90°C. More preferably, the processing temperature is 30°C to 80°C, and even more preferably 40°C to 70°C.

[0197] The oligoamine compound used to prepare the impregnation solution may contain a carbamic acid (salt) structure. When using an oligoamine compound without a carbamic acid (salt) structure as a raw material, the oligoamine compound can be made into an oligoamine compound with a carbamic acid (salt) structure by the fourth step described below (4). Alternatively, when using an oligoamine compound without a carbamic acid (salt) structure as a raw material, it can be contacted with a gas containing carbon dioxide in this step to form a carbamic acid (salt) structure.

[0198] (3) The third step of separating the hydrophilic silica gel impregnated with the impregnation solution from the excess impregnation solution.

[0199] Separation can be achieved using any solid-liquid separation method, such as filtration, decantation, or centrifugation. Considering the simplicity of the process, filtration is the preferred method.

[0200] (4) The fourth step is to dry the hydrophilic silica gel impregnated with the impregnation solution by evaporating water in an atmosphere containing carbon dioxide.

[0201] Any method can be used to dry the water.

[0202] The preferred drying temperature is 30℃~100℃, more preferably 40℃~98℃, even more preferably 50℃~95℃, and most preferably 50℃~90℃.

[0203] The processing time is preferably 0.1 hours to 48 hours, more preferably 0.2 hours to 24 hours, and even more preferably 0.5 hours to 12 hours.

[0204] The processing pressure can be arbitrarily selected as atmospheric pressure or reduced pressure. In order to effectively utilize the interaction between the hydrophilic silica and the composition, and to maintain the composition within the pores and allow moisture to evaporate slowly, it is preferable to carry out the process under atmospheric pressure.

[0205] If the above conditions are met, then the macropores can be dried and the carbon dioxide separation composition can be efficiently loaded in the mesopores / micropores, and the carbon dioxide absorption site can be efficiently manufactured (i.e., a carbamate (salt) structure is formed).

[0206] Carbon dioxide

[0207] In the process of evaporating water, in order to allow the impregnating liquid to effectively penetrate into the micropores / mesopores within the hydrophilic silica gel, a portion of the oligoamine compound is made into an urethane (salt) structure under an atmosphere containing carbon dioxide.

[0208] Treatment using an atmosphere containing carbon dioxide can be carried out using any method and under any conditions. For example, it can be performed with ventilation or in a closed space. The treatment time is preferably 5 to 900 minutes, more preferably 10 to 600 minutes, and particularly preferably 15 to 300 minutes.

[0209] The concentration of carbon dioxide in the atmosphere containing carbon dioxide is preferably 0.01% by volume or more and 20% by volume or less, more preferably 0.02% by volume or more and 15% by volume or less, even more preferably 0.03% by volume or more and 10% by volume or less, and particularly preferably 0.035% by volume or more and 5% by volume or less. By setting the carbon dioxide concentration within the above range, the carbamate (salt) structure is generated efficiently. By adopting the carbamate (salt) structure for a portion of the oligoamine compound, the affinity between the impregnation liquid and the surface of the hydrophilic silica gel is improved. Therefore, the impregnation liquid can easily penetrate into the micropores or mesopores of the hydrophilic silica gel. After the water evaporates, the carbon dioxide separation composition is retained in the micropores or mesopores, forming an absorption site. In addition to carbon dioxide, the atmosphere containing carbon dioxide may also contain nitrogen, oxygen, argon, etc.

[0210] The operation of converting a portion of the amine structure into a carbamic acid (salt) structure can be carried out not only in the process of evaporating water, but also in the process of preparing the impregnation solution and the process of impregnating the impregnation solution with hydrophilic silica gel.

[0211] According to one embodiment, the method for manufacturing a solid absorbent material for carbon dioxide separation satisfies one or more of the following groups (a) to (c):

[0212] (a) The second process is carried out in a temperature range of 20°C to 90°C;

[0213] (b) The second step includes a step of degassing the hydrophilic silica gel pores under a reduced pressure of -0.08 MPaG to -0.004 MPaG;

[0214] (c) The fourth process uses air as an atmosphere containing carbon dioxide and is carried out in a temperature range of 30°C to 100°C.

[0215] By using a manufacturing method that satisfies one or more of the groups consisting of (a) to (c) above to manufacture a solid absorbent material for carbon dioxide separation, it is possible to further increase the adsorption and desorption of carbon dioxide in a solid absorbent material carrying a composition for carbon dioxide separation.

[0216] Example

[0217] The following examples illustrate the present invention in detail, but the invention is not limited to these examples. Furthermore, unless otherwise specified, "parts" refers to "parts by weight" and "%" refers to "% by weight". In addition, unless otherwise stated, all operations are performed at room temperature (25°C).

[0218] The oligoamine compounds used in the following examples and comparative examples are described below.

[0219] • Polyethyleneimine (Mn=600): Manufactured by Nippon Shokubai Co., Ltd., "EPOMIN (registered trademark) SP-006" (contains 35% primary amines (primary amine structure) in all amines)

[0220] • Polyethyleneimine (Mn=300): Manufactured by Nippon Shokubai Co., Ltd., “EPOMIN (registered trademark) SP-003” (containing 45% primary amines (primary amine structure) in all amines).

[0221] The modifiers used in the following examples and comparative examples are described below.

[0222] • PEG200 (Mn=200): Polyethylene glycol 200 manufactured by Fujifilm and Koujun Pharmaceutical Co., Ltd. (ΔD: 16.73, ΔP: 9.02, ΔH: 14.58 / Boiling point above 300°C and below 350°C)

[0223] • PEG300 (Mn=300): Polyethylene glycol 300 manufactured by Fujifilm and Koichi Pure Chemical Industries Co., Ltd. (ΔD: 16.24, ΔP: 8.15, ΔH: 11.8 / Boiling point > 350℃)

[0224] • PEG400 (Mn=400): Polyethylene glycol 400 manufactured by Tokyo Chemical Industry Co., Ltd. (ΔD: 15.73, ΔP: 7.47, ΔH: 9.68 / Boiling point > 350℃)

[0225] •MePEG450 (Mn=450): Polyethylene glycol monomethyl ether 450 manufactured by Tokyo Chemical Industry Co., Ltd. (ΔD: 15.73, ΔP: 6.26, ΔH: 8.84 / boiling point > 350℃).

[0226] The porous materials used in the following embodiments and comparative examples are described below.

[0227] As a comparative example of porous materials, regular mesoporous silica was precisely synthesized using tetraalkoxysilane and template compounds.

[0228] • SBA-15 (particle size below 150μm): Mesoporous silica manufactured by Aldrich.

[0229] As a comparative example and embodiment, the porous material used is a hydrophilic silica gel obtained by grading the following commercially available products or a hydrophilic silica gel obtained by grading and crushing commercially available products.

[0230] • Q-10 (particle size range 75-212μm): Use CARiACT (registered trademark) Q-10 (particle size range 75-500μm) manufactured by FUJI SILYSIA Co., Ltd. for classification.

[0231] • Q-30CR (particle size 53-212μm): Used for crushing and grading CARiACT (registered trademark) Q-30 (particle size range 1.18-2.36mm) manufactured by FUJI SILYSIA.

[0232] • Q-50CR (particle size range 53-212μm): Used after crushing and classifying CARiACT (registered trademark) Q-50 (particle size range 1.18-2.36mm) manufactured by FUJI SILYSIA.

[0233] As a comparative example and embodiment, the porous material used is a commercially available hydrophilic silicone.

[0234] • P-78F (average particle size 18μm): MIZUKASIL (registered trademark) P-78F manufactured by Mizusawa Chemical Industry Co., Ltd.

[0235] • Q-15 (particle size range 180-500μm): CARiACT (registered trademark) Q-15 manufactured by FUJI SILYSIA.

[0236] • Q-30 (particle size range 75-500μm): CARiACT (registered trademark) Q-30 manufactured by FUJI SILYSIA.

[0237] Table 1 shows the characteristics of the porous materials used in the comparative examples and embodiments.

[0238] [Table 1]

[0239]

[0240] The values ​​in Table 1 above are from the catalog; values ​​not previously published were measured. For Q-10, Q-30CR, and Q-50CR, pore volume, average pore size, and specific surface area were measured using a BELSORP MAX manufactured by MicrotracBEL, confirming no change in pore volume, average pore size, and specific surface area compared to silica gel before grading, crushing, or grading. For P-78, Q-15, and Q-30, pore volume, average pore size, and specific surface area are from the catalog.

[0241] The pore volume, average pore size, and specific surface area of ​​SBA-15 were measured using a BELSORP MAX manufactured by MicrotracBEL. The volumetric specific gravity of each silica gel was calculated by filling a graduated cylinder with a certain weight of porous material according to JIS R 1628-1997 and measuring the volume. The particle size range for each silica gel is specified by the mesh size of the sieve used in the grading. That is, "particle size range 75-212 μm" indicates silica gel particles that pass through a sieve with a mesh size of 212 μm but not through a sieve with a mesh size of 75 μm. The moisture adsorption capacity of each silica gel was determined according to the method described above in <Evaluation of Hydrophilicity of Pore Inner Surface: Determination of Moisture Adsorption Capacity in Low Humidity Nitrogen>, with a moisture adsorption capacity of 0.00002 g / m³. 2 The above-mentioned silicone is a hydrophilic silicone.

[0242] For the formulation examples of the impregnating solutions used in the comparative and exemplary cases, the formulation ratios of the raw material oligoamine compound and the modifier are shown in Table 2. Furthermore, Table 2 shows the total amine value and primary amine content of the raw material oligoamine compound before the formation of the carbamic acid (salt) structure.

[0243] [Table 2]

[0244]

[0245] [Manufacturing Example 1: Preparation of solid absorbent materials for carbon dioxide separation according to Comparative Examples 1-5]

[0246] The oligoamine compound and modifier, in proportions shown in Table 2, were weighed into a glass container to a total of 1 g. 10 g of methanol was added, and the mixture was stirred at room temperature for 30 minutes using a magnetic stirrer to prepare an impregnation solution for the carbon dioxide separation composition. 1 g of the powdered porous material shown in Tables 3 and 4 was added to the impregnation solution, and impregnation was carried out while stirring for 30 minutes. Next, a solvent removal process using an evaporator (bath temperature 60°C, 50 kPa) was performed, followed by a drying process under reduced pressure at 60°C, 20 Pa, to obtain a solid absorbent material for carbon dioxide separation containing the oligoamine compound and modifier from Formulation Examples 1 and 2, which was loaded onto the porous material.

[0247] [Manufacturing Example 2: Preparation of solid absorbent materials for carbon dioxide separation according to Examples 1-9]

[0248] The oligoamine compound and modifier, in proportions shown in Table 2, were weighed into a glass container to a total of 10g. 10g of water was added, and the mixture was stirred at room temperature for 30 minutes using a magnetic stirrer to prepare an impregnation solution for the carbon dioxide separation composition. 1g of the powdered porous material shown in Tables 3 and 4 was added to the impregnation solution, and the mixture was stirred for 5 minutes. Then, the impregnation solution impregnated with the porous material was subjected to a reduced pressure of 50kPa at 40°C to remove air bubbles inside the porous material, allowing the impregnation solution to penetrate into the pores. Next, the remaining impregnation solution was removed by filtration, and the mixture was dried at 60°C for 6 hours in an atmosphere containing carbon dioxide (nitrogen gas containing 400 ppm of carbon dioxide) to obtain a solid absorbent material for carbon dioxide separation containing the oligoamine compound and modifier described in Examples 3-10, mounted on a porous material.

[0249] [Manufacturing Example 3: Preparation of solid absorbent materials for carbon dioxide separation in Comparative Examples 6-8 and 10]

[0250] The oligoamine compound and modifier, in proportions shown in Table 2, were weighed into a glass container to a total of 10g. 10g of water was added, and the mixture was stirred at room temperature for 30 minutes using a magnetic stirrer to prepare an impregnation solution for the carbon dioxide separation composition. 1g of the powdered porous material shown in Tables 3 and 4 was added to the impregnation solution, and the mixture was stirred for 5 minutes. Next, the remaining impregnation solution was removed by vacuum filtration, and the mixture was left to stand overnight in room temperature air to obtain a solid absorbent material for carbon dioxide separation containing the oligoamine compound and modifier from Formulation Examples 3 and 10, which was loaded onto the porous material.

[0251] [Manufacturing Example 4: Preparation of Solid Absorbent Material for Carbon Dioxide Separation in Comparative Example 9]

[0252] The oligoamine compound and modifier, in proportions shown in Table 2, were weighed into a glass container to a total of 10g. 10g of water was added, and the mixture was stirred at room temperature for 30 minutes using a magnetic stirrer to prepare an impregnation solution of the carbon dioxide separation composition. 1g of the powdered porous material shown in Tables 3 and 4 was added to the impregnation solution. The mixture was then subjected to ultrasonic irradiation at 40°C for 30 minutes and oscillated, and dried at 80°C and 0.1kPa for 2 hours to obtain a solid absorbent material for carbon dioxide separation containing the oligoamine compound and modifier of Formulation Example 10, which was loaded onto the porous material.

[0253] [Containment and percentage of carbamic acid (salt) structures in the oligoamine compounds of the carbon dioxide separation composition]

[0254] Regarding the formation of carbamic acid (salt) structures in oligoamine compounds, the carbon dioxide separation composition in solid absorbent materials for carbon dioxide separation is dissolved in heavy water for determination. 13 C-NMR was used to calculate the area Ac by integrating the signal (peak) originating from the 13C structure of carbamate (salt) at 163–166 ppm, and the area Am by integrating the signal (peak) originating from the 13C structure of methylene (salt) at 36–58 ppm. The content C (%) of the carbamate (salt) structure was then calculated using the following formula. Additionally, the intensity correction factor F for the signal (peak) originating from the 13C structure of carbamate (salt) and the signal (peak) originating from the 13C structure of methylene (salt) was used. This factor was calculated by dissolving monoethanolamine and CO2 in heavy water and measuring the equimolar area ratio of the signal (peak) originating from the carbamate (salt) structure to the signal (peak) originating from the methylene structure; F = 0.366 was used.

[0255] Content of carbamic acid (salt) structure: C (%)

[0256] = (Area of ​​13C of carbamate (salt) structure: Ac) ÷ (Area of ​​13C of methylene structure: Am) ÷ (Intensity correction factor: F).

[0257] [Total amine value and primary amine content in oligoamine compounds]

[0258] In the composition for carbon dioxide separation, the total amine value and the content of primary amine compounds were calculated and shown in Tables 3 and 4. Furthermore, the carbamate (salt) structure of the oligoamine compounds causes carbon dioxide to be released during the determination of the total amine value, thus the nitrogen atoms forming the carbamate (salt) structure are calculated in the form of amines. Therefore, the total amine value of the oligoamine compounds is the same as that of the aforementioned raw material oligoamine compounds.

[0259] [Determination of moisture content in the composition for carbon dioxide separation]

[0260] For the solid absorbent materials for carbon dioxide separation in Examples 1 to 9, the water content in the carbon dioxide separation composition contained in the solid absorbent materials for carbon dioxide separation was determined by differential thermal analysis after drying at 120°C for 1 hour in a dry nitrogen stream.

[0261] The water content in the carbon dioxide separation composition contained in the solid absorbent materials for carbon dioxide separation in Examples 1-9 is 1% to 30% by weight relative to the total weight of the carbon dioxide separation composition. The water content in each carbon dioxide separation composition is shown in Tables 3 and 4.

[0262] [Determination of moisture content in solid absorbent materials]

[0263] For the solid absorbent materials for carbon dioxide separation in Examples 1-9, the moisture content in the solid absorbent materials was determined by differential thermal analysis after drying at 120°C for 1 hour in a dry nitrogen stream.

[0264] The water content in the solid absorbent materials for carbon dioxide separation in Examples 1-9 is 4% to 12% by weight relative to the total weight of the solid absorbent materials for carbon dioxide separation. Furthermore, the water content in each solid absorbent material for carbon dioxide separation can be calculated using the water content of the carbon dioxide separation compositions shown in Tables 3 and 4 as described below.

[0265] [Conversion formula for water content of solid absorbent materials]

[0266] Moisture content (by weight) in solid absorbent materials

[0267] = [(weight parts of oligoamine compounds and modifiers in the solid absorbent material: non-volatile components) × (moisture content of the composition for carbon dioxide separation) ÷ {100 - (moisture content of the composition for carbon dioxide separation)}] ÷ (100 + [(weight parts of oligoamine compounds and modifiers in the solid absorbent material: non-volatile components) × (moisture content of the composition for carbon dioxide separation) ÷ {100 - (moisture content of the composition for carbon dioxide separation)}]).

[0268] [Calculation of the loading of non-volatile components in the carbon dioxide separation composition of the solid absorbent material for carbon dioxide separation]

[0269] The loading of non-volatile components in the carbon dioxide separation composition was calculated according to the method described above in "Calculation of the loading of non-volatile components in the carbon dioxide separation composition on hydrophilic silica gel based on thermogravimetric analysis". The calculated loading of non-volatile components in the solid absorbent material for carbon dioxide separation is shown in Tables 3 and 4 in the form of the weight ratio of porous material to formulation example (a formulation of oligoamine compound and modifier).

[0270] [Carbon Dioxide Desorption Test]

[0271] Using the obtained solid absorbent material for carbon dioxide separation, two carbon dioxide desorption tests were conducted according to the methods described above: <Carbon Dioxide Adsorption-Desorption Test Using Carbon Dioxide-Containing Gas in Simulated Dry Atmosphere> and <Carbon Dioxide Adsorption-Desorption Test Using Carbon Dioxide-Containing Gas in Simulated Dry Enclosed Space>. The results are shown in Tables 3 and 4.

[0272] [Table 3]

[0273]

[0274] According to the results in Table 3, as shown in Comparative Examples 3-5, in the conventional manufacturing method: Manufacturing Example 1, even when the modified carbon dioxide separation composition of Formulation Example 2 was loaded onto silica gel, the results were worse in terms of adsorption / desorption capacity and amine efficiency compared to Comparative Examples 1 and 2, which used regular mesoporous silica. On the other hand, by implementing the manufacturing method of the present invention: Manufacturing Example 2, the adsorption / desorption capacity and amine efficiency were improved, and performance comparable to Comparative Example 2 (SBA-15: mesoporous silica, reproducibility confirmation of Non-Patent Document 4) was achieved. Moreover, as shown in Examples 1-8, by using a solid absorbent material for carbon dioxide separation loaded with the composition of the present invention, it is possible to produce a solid absorbent material with performance significantly exceeding that of prior art solid absorbent materials, achieving a solid absorbent material with large adsorption / desorption capacity and high amine efficiency.

[0275] [Table 4]

[0276]

[0277] According to the results in Table 4, as shown in Comparative Examples 3-5, in the conventional manufacturing method: Manufacturing Example 1, even when the modified carbon dioxide separation composition of Formulation Example 2 was loaded onto silica gel, no significant advantage was observed in terms of adsorption / desorption capacity and amine efficiency compared to Comparative Examples 1 and 2 using regular mesoporous silica. Furthermore, even when the manufacturing method: Manufacturing Example 3 was implemented, no significant advantage was observed in terms of adsorption / desorption capacity and amine efficiency in Comparative Examples 7 and 8. On the other hand, as shown in Examples 1-3 and 6-9, by using a solid absorbent material for carbon dioxide separation loaded with the composition of the present invention, it is possible to produce a solid absorbent material with performance significantly exceeding that of prior art, achieving a large adsorption / desorption capacity and high amine efficiency.

[0278] As shown in Tables 3 and 4, the solid absorbent material for carbon dioxide separation in the embodiments can efficiently separate or recover carbon dioxide from gas compositions containing low partial pressure or low concentration carbon dioxide under the temperature and humidity conditions envisioned in actual operation.

[0279] Industrial availability

[0280] The carbon dioxide separation composition and solid absorbent material of the present invention are suitable for, for example, separating and recovering carbon dioxide (DAC) from the air, separating and recovering carbon dioxide from exhaust gases from power plants or factories, and removing carbon dioxide from enclosed spaces such as submarines or spacecraft.

[0281] Furthermore, this application is based on Japanese Patent Application No. 2023-188170, filed on November 2, 2023, the disclosure of which is incorporated herein by reference in its entirety.

Claims

1. A composition for carbon dioxide separation, comprising: Oligoamine compounds with boiling points above 200℃; and Modifiers with a boiling point above 200℃; A portion of all the nitrogen atoms in the oligoamine compound has an amino carboxylic acid or salt thereof structure. The proportion of nitrogen atoms forming carbamic acid or its salt structure in the oligoamine compound is 0.1% to 20% relative to all nitrogen atoms in the compound.

2. The composition for carbon dioxide separation according to claim 1, wherein, The water content is 1% to 30% by weight relative to the total weight of the carbon dioxide separation composition.

3. The composition for carbon dioxide separation according to claim 1 or 2, wherein, The oligoamine compound is polyethyleneimine with a number average molecular weight of 200 or more and less than 2000.

4. The composition for carbon dioxide separation according to claim 1 or 2, wherein, The oligoamine compound is a compound in which the primary amine structure accounts for more than 5% of the total amine structure.

5. The composition for carbon dioxide separation according to claim 1 or 2, wherein, The modifier has an HSP value of ΔD of 12 or more and 22 or less, ΔP of 5 or more and 15 or less, and ΔH of 3 or more and 30 or less.

6. The composition for carbon dioxide separation according to claim 1 or 2, wherein, The modifier is a compound having a polyethylene glycol structure.

7. A solid absorbent material for carbon dioxide separation, which is formed by loading the carbon dioxide separation composition according to claim 1 or 2 onto hydrophilic silica gel.

8. The solid absorbent material for carbon dioxide separation according to claim 7, wherein, The physical properties of the hydrophilic silica gel satisfy one or more of the group consisting of (i) to (iv) below; (i) The pore volume is 0.6 cm 3 / g~3.0cm 3 / g; (ii) The average pore size is 5 nm to 80 nm; (iii) Specific surface area is 70m² 2 / g~800m 2 / g; (iv) Specific gravity is 0.10 g / cm³ 3 above.

9. The solid absorbent material for carbon dioxide separation according to claim 7, wherein it is selected from one or more of the group consisting of (i) and (ii) below; (i) In the carbon dioxide adsorption-desorption test using air with a carbon dioxide concentration of 300 to 500 ppm and an absolute humidity of 2 g / kg or less, in the process of releasing the carbon dioxide absorbed by the above-mentioned solid absorbent material at 40°C at 70°C, the amount of carbon dioxide adsorbed and desorbed per gram of solid absorbent material is 0.90 mmol or more, and the amount of carbon dioxide adsorbed and desorbed per mole of amine contained in the solid absorbent material is 0.20 mol or more. (ii) In the carbon dioxide adsorption-desorption test using air with a carbon dioxide concentration of 9000 ppm to 11000 ppm and an absolute humidity of 2 g / kg or less, in the process of releasing the carbon dioxide absorbed by the above-mentioned solid absorbent material at 70°C at 100°C, the amount of carbon dioxide adsorbed and desorbed per gram of solid absorbent material is 1.30 mmol or more, and the amount of carbon dioxide adsorbed and desorbed per mole of amine contained in the solid absorbent material is 0.20 mol or more.

10. A method for manufacturing a solid absorbent material for carbon dioxide separation, comprising: (1) The first step is to prepare an impregnation solution containing an oligoamine compound with a boiling point of 200°C or higher, a modifier with a boiling point of 200°C or higher, and water. (2) The second step is to immerse the hydrophilic silica gel in the impregnation solution; (3) The third step involves separating the hydrophilic silica gel impregnated with the impregnation solution from the excess impregnation solution; and (4) Fourth step: The hydrophilic silica gel impregnated with the impregnation liquid is dried by evaporating water in an atmosphere containing carbon dioxide.

11. The method for manufacturing a solid absorbent material for carbon dioxide separation according to claim 10, wherein it satisfies the condition of being selected from one or more of the group consisting of (a) to (c) below; (a) The second process is carried out in a temperature range of 20°C to 90°C; (b) The second step includes a step of degassing the hydrophilic silica gel pores under a reduced pressure of -0.08 MPaG to -0.004 MPaG; (c) The fourth process uses air as an atmosphere containing carbon dioxide and is carried out in a temperature range of 30°C to 100°C.

Images