Amine composition for carbon dioxide separation

Abstract

To provide a composition for carbon dioxide separation improved in ability to completely removing carbon dioxide from a gas mixture containing low-concentration carbon dioxide.SOLUTION: A composition for carbon dioxide separation comprises an amine compound represented by the general formula (1) in the figure, and an amine compound (2) such as piperazine.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a carbon dioxide separation composition for separating carbon dioxide from a mixed gas containing carbon dioxide. [Background technology]

[0002] The present invention relates to, for example, a carbon dioxide separation composition for removing and capturing CO2 from synthesis gas.

[0003] Synthetic gas, which is primarily composed of hydrogen and carbon monoxide, is used as a raw material for producing useful intermediate raw materials for the chemical industry, such as methanol and oxoalcohols.

[0004] The synthesis gas can be produced, for example, by introducing raw hydrocarbons, steam, and carbon dioxide gas into a nickel-based catalyst and reacting them under a high-temperature environment of about 800 to 900°C and a high-pressure environment of about 20 to 30 atm. A reformed gas containing H, CO, CO, HO, and CH as main components is obtained as a reaction product, and the reformed gas from which CO and HO have been removed is used as synthesis gas. The removed CO is reused as a raw material for producing synthesis gas.

[0005] Cited Document 2 discloses that a scrubbing device using methyldiethanolamine is used as a method for removing CO2 from crude synthesis gas (reformed gas). Furthermore, by treating the synthesis gas from which CO2 has been removed in a cryogenic separation device, carbon monoxide, which is important as a basic raw material for heavy chemical industries, can be isolated and purified. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 11-132651 [Patent Document 2] Special Publication No. 2008-528423 Summary of the Invention [Problem to be solved by the invention]

[0007] Regarding CO2 removal using the above-mentioned methyldiethanolamine, the absorption rate of carbon dioxide at low concentrations is low, i.e., the ability to completely remove carbon dioxide is insufficient. As a result, trace amounts of CO2 were observed to flow into the cryogenic separation device. Such trace amounts of CO2 condense inside the cold box of the cryogenic separation device, causing problems such as clogging of the equipment and gas flow paths (e.g., Patent Document 1).

[0008] The present invention has been made in view of the above-mentioned problems, and its object is to provide a carbon dioxide separation composition that has a superior ability to remove carbon dioxide (higher carbon dioxide absorption rate at low concentrations) than known compositions. [Means for solving the problem]

[0009] As a result of extensive research into solving the above problems, the present inventors discovered the composition described below and completed the present invention.

[0010] That is, the present invention relates to a composition for separating carbon dioxide as shown below.

[0011] [1] A composition for carbon dioxide separation, comprising an amine compound represented by the following general formula (1) (hereinafter referred to as "amine compound (1)") and an amine compound represented by the following general formula (2) (hereinafter referred to as "amine compound (2)"):

[0012] [ka]

[0013] [In the above general formula (1), R 10 , R 11 , R 12 , R 13 and R 14each independently represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, a hydroxyl group, a hydroxymethyl group, a 2-hydroxyethyl group, or an alkoxy group having 1 to 4 carbon atoms. a and b each independently represent 0 or 1, and satisfy the relationship a+b=1. R 15 represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, a methoxymethyl group, a methoxyethoxymethyl group, or a 2-hydroxyethyl group.]

[0014] [ka]

[0015] [In the above general formula (2), R 4 and R 5 each independently represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, a hydroxymethyl group, a 2-hydroxyethyl group, an aminoalkyl group having 3 to 4 carbon atoms, or a hydroxyalkyl group having 3 to 4 carbon atoms. R 4 and R 5 may be bonded to each other to form a ring. R 6 represents an alkylene group having 1 to 4 carbon atoms. [2] The amine compound (1) is represented by the following formula:

[0016] [ka]

[0017] The carbon dioxide separation composition according to [1], characterized in that it is 1,4-diazabicyclo[2.2.2]octane-2-methanol represented by the following formula:

[0018] [3] The amine compound (2) is represented by the following formula:

[0019] [ka]

[0020] The carbon dioxide separation composition according to [1] or [2], characterized in that it is a piperazine represented by the following formula:

[0021] [4] The composition for carbon dioxide separation according to any one of [1] to [3] above, characterized in that the composition ratio of the amine compound (1) to the amine compound (2) is 5 to 100 parts by weight of the amine compound (2) per 100 parts by weight of the amine compound (1).

[0022] [5] The carbon dioxide separation composition according to any one of [1] to [4] above, further comprising, in addition to the amine compound (1) and the amine compound (2), at least one amine compound (3) selected from the group consisting of alkanolamines, propylenediamines, piperazines, piperidines, morpholines, pyrrolidines, azepanes, and polyethylenepolyamines (excluding the amine compounds (1) and (2)).

[0023] [6] A composition for carbon dioxide separation according to any one of [1] to [5] above, further comprising water, wherein the concentration of the water is 30 to 95% by weight of the entire composition for carbon dioxide separation containing water.

[0024] [7] A method for separating carbon dioxide, comprising the step of contacting a gas containing carbon dioxide with the carbon dioxide separation composition described in any one of [1] to [6] above, to absorb the carbon dioxide in the mixed gas. [Effects of the Invention]

[0025] The carbon dioxide separation composition of the present invention has a higher carbon dioxide absorption rate per unit time than conventionally known materials, and has the effect of being able to absorb and separate even low concentrations of carbon dioxide at high speed and with a small amount of the carbon dioxide separation composition. Therefore, the present invention is extremely useful industrially, particularly when a subsequent cryogenic separation step is included, in that it can more effectively remove impurities that may precipitate. DETAILED DESCRIPTION OF THE INVENTION

[0026] The present invention will be described in detail below.

[0027] First, the carbon dioxide separation composition of the present invention will be described.

[0028] The carbon dioxide separation composition of the present invention is characterized by containing the above-mentioned amine compound (1) and the above-mentioned amine compound (2).More specifically, for example, a more preferable carbon dioxide separation composition is prepared by dissolving a mixture of the above-mentioned amine compound (1) and amine compound (2) in a solvent such as water.

[0029] In the present invention, the above amine compounds (1) and (2) both play a role in absorbing and releasing carbon dioxide.

[0030] In the present invention, R 10 , R 11 , R 12 , R 13 , and R 14 each independently represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, a hydroxyl group, a hydroxymethyl group, a 2-hydroxyethyl group, or an alkoxy group having 1 to 4 carbon atoms.

[0031] In the present invention, R 10 , R 11 , R 12 , R 13 , and R 14are not particularly limited as long as they fall within the definition above, and examples of groups that can be independently selected include a hydrogen atom, a methyl group, an ethyl group, an n-propyl group, an isopropyl group, a butyl group (more specifically, an n-butyl group, an isobutyl group, a sec-butyl group, or a tert-butyl group), a hydroxyl group, a hydroxymethyl group, a 2-hydroxyethyl group, a methoxy group, an ethoxy group, an n-propoxy group, an isopropoxy group, an n-butoxy group, or a sec-butoxy group. Of these, in terms of excellent carbon dioxide diffusion efficiency, preferably, each independently selected is a hydrogen atom, a methyl group, an ethyl group, a butyl group, a hydroxymethyl group, or a methoxy group, and more preferably a hydrogen atom.

[0032] In the present invention, R 15 represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, a methoxymethyl group, a methoxyethoxymethyl group, or a 2-hydroxyethyl group.

[0033] In addition, R in the above amine compound (1) 15 is not particularly limited as long as it satisfies the above definition, and examples thereof include a hydrogen atom, a methyl group, an ethyl group, an n-propyl group, an isopropyl group, a butyl group (more specifically, an n-butyl group, an isobutyl group, a sec-butyl group, or a tert-butyl group), a methoxymethyl group, a methoxyethoxymethyl group, or a 2-hydroxyethyl group. Of these, in terms of excellent carbon dioxide diffusion efficiency, a hydrogen atom, a methyl group, an ethyl group, a butyl group, a methoxymethyl group, a methoxyethoxymethyl group, or a 2-hydroxyethyl group is preferred, and a hydrogen atom is more preferred.

[0034] In the above amine compound (1), a and b are each independently 0 or 1, and satisfy the relationship a+b=1.

[0035] When a=1 and b=0, the above general formula (1) is represented by the following general formula (1a) (hereinafter referred to as "amine compound (1a)").

[0036] [ka]

[0037] [In the above general formula (1a), R 10 , R 11 , R 12 , R 13 , R 14 , and R 15 The definition and preferred range of R 10 , R 11 , R 12 , R 13 , R 14 , and R 15 The definition and preferred range are the same as those of the above.] When a=0 and b=1, the above general formula (1) is represented by the following general formula (1b) (hereinafter referred to as "amine compound (1b)").

[0038] [ka]

[0039] [In the above general formula (1b), R 10 , R 11 , R 12 , R 13 , R 14 , and R 15 The definition and preferred range of R 10 , R 11 , R 12 , R 13 , R 14 , and R 15 The definition and preferred range are the same as those of the above.] Specific examples of the amine compound (1) include the following compounds (exemplary compounds 1 to 28), but the present invention is not limited to these.

[0040] [ka]

[0041] Regarding the above amine compound (1), from the viewpoint of availability, 1,4-diazabicyclo[2.2.2]octane-2-methanol (R 10 =R 11 =R 12 =R 13 =R 14 =R 15 = hydrogen atom, a = 0, b = 1, and the above-mentioned exemplary compound 1) is preferred. That is, the amine compounds represented by the following chemical structural formula are preferred.

[0042] [ka]

[0043] In the amine compound (2) of the present invention, R 4 and R 5 each independently represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, a hydroxymethyl group, a 2-hydroxyethyl group, an aminoalkyl group having 3 to 4 carbon atoms, or a hydroxyalkyl group having 3 to 4 carbon atoms. 4 and R 5 may be bonded to each other to form a ring. 6 represents an alkylene group having 1 to 4 carbon atoms.

[0044] R in amine compound (2) 4 and R 5 are each independently preferably a hydrogen atom, a methyl group, an ethyl group, a 2-hydroxyethyl group, a 2-hydroxypropyl group, or a 3-aminopropyl group, in terms of excellent carbon dioxide adsorption / desorption efficiency, and R 4 and R 5 more preferably, R are bonded to each other to form a ring, 4 and R 5 is more preferably a methyl group, and the methyl groups are bonded to each other to form 1,2-ethylene.

[0045] R in amine compound (2) 6represents an alkylene group having 1 to 4 carbon atoms, and is not particularly limited to, but examples thereof include a methylene group, a 1,2-ethylene group, a 1,3-propylene group, and a 1,4-butylene group. In terms of excellent carbon dioxide adsorption / desorption efficiency, 1,2-ethylene or 1,3-propylene is preferred, and 1,2-ethylene is more preferred.

[0046] In the above amine compound (2), R 4 and R 5 The compounds bonded to each other to form a ring are not particularly limited, but an amine compound represented by the following general formula (2a) is preferred because of its excellent carbon dioxide absorption efficiency.

[0047] [ka]

[0048] [In the above general formula (2a), R 7 each independently represents an alkylene group having 1 to 4 carbon atoms. R in general formula (2a) 7 The definition and preferred range of (C1-C4 alkylene) are as follows: R 6 The definition and preferred range are the same as those of (alkylene having 1 to 4 carbon atoms).

[0049] Specific examples of the amine compound represented by general formula (2) include N,N'-dimethyl-1,4-diaminobutane, N-methyl-1,4-diaminobutane, N,N'-dimethyl-1,3-diaminopropane, N-methyl-1,3-diaminopropane, N,N'-dimethyl-1,2-diaminopropane, N-methyl-1,2-diaminopropane, N,N'-dimethyl-1,2-diaminoethane, N-methyl-1,2-diaminoethane, N,N'-diethyl-1,4-diaminobutane, N-ethyl-1,4-diaminobutane, N,N'-diethyl-1,3-diaminopropane, N-ethyl-1,3-diaminopropane, N,N'-diethyl-1,2-diaminopropane, Examples of the amino groups include N-ethyl-1,2-diaminopropane, N,N'-diethyl-1,2-diaminoethane, N-ethyl-1,2-diaminoethane, N,N'-dipropyl-1,4-diaminobutane, N-propyl-1,4-diaminobutane, N,N'-dipropyl-1,3-diaminopropane, N-propyl-1,3-diaminopropane, N,N'-dipropyl-1,2-diaminopropane, N-propyl-1,2-diaminopropane, N,N'-dipropyl-1,2-diaminoethane, N-propyl-1,2-diaminoethane, piperazine, N-(2-aminoethyl)-2-aminoethanol, and 2-(3-aminopropyl)-2-aminoethanol.

[0050] Regarding the above amine compound (2), from the viewpoint of availability, N,N'-dimethyl-1,3-diaminopropane (R 4 =R 5 = methyl group, R 6 = 1,3-propylene), and N,N'-dimethyl-1,2-diaminoethane (R 4 =R 5 = methyl group, R 6 Preferably, the amine is at least one amine selected from the group consisting of N-(2-aminoethyl)-2-aminoethanol, N-(3-aminopropyl)-2-aminoethanol, N-(2-aminoethyl)-2-aminoethanol, N-(2-aminoethyl)-2-aminoethanol, and N-(3-aminopropyl)-2-aminoethanol.

[0051] The carbon dioxide separation composition of the present invention, which is characterized by containing the above-mentioned amine compound (1) and the above-mentioned amine compound (2), is preferably a carbon dioxide separation composition characterized by containing amine compound (1), which is 1,4-diazabicyclo[2.2.2]octane-2-methanol, and at least one amine compound (2) selected from the group consisting of piperazine, N,N'-dimethyl-1,3-diaminopropane, N,N'-dimethyl-1,2-diaminoethane, N-(2-aminoethyl)-2-aminoethanol, and 2-(3-aminopropyl)-2-aminoethanol, in that it has an excellent carbon dioxide absorption rate.

[0052] In terms of a fast carbon dioxide absorption rate, the composition ratio of amine compound (1) to amine compound (2) of the present invention is preferably 5 to 100 parts by weight of amine compound (2) per 100 parts by weight of amine compound (1), more preferably 10 to 70 parts by weight of amine compound (2) per 100 parts by weight of amine compound (1), and even more preferably 20 to 40 parts by weight of amine compound (2) per 100 parts by weight of amine compound (1).

[0053] In the present invention, the amine compounds represented by the general formulas (1) and (2) may be commercially available or synthesized by known methods, and are not particularly limited. The purity of these amine compounds is not particularly limited, but is preferably 95% or higher, and more preferably 99% or higher. If the purity is lower than 95%, the amount of carbon dioxide absorbed may decrease.

[0054] The carbon dioxide separation composition of the present invention may contain, in addition to amine compound (1) and amine compound (2), at least one amine compound (3) different from these selected from the group consisting of alkanolamines, propylenediamines, piperazines, piperidines, morpholines, pyrrolidines, azepanes, and polyethylenepolyamines. The presence of amine compound (3) may increase the N atom content per unit weight of the carbon dioxide separation composition, which may be industrially advantageous in that it increases the carbon dioxide absorption amount per unit weight of the carbon dioxide separation composition.

[0055] In the present invention, specific examples of the alkanolamines include ethanolamine, N-methylethanolamine, N,N-dimethylethanolamine, diethanolamine, N-[2-(dimethylamino)ethyl]-N-methylethanolamine, N-[2-(diethylamino)ethyl]-N-ethylethanolamine, 2-(2-aminoethoxy)ethanol, 2-[2-(dimethylamino)ethoxy]ethanol, 2-[2-(diethylamino)ethoxy]ethanol, N-[2-(2-aminoethoxy)ethyl]ethanolamine, N-[2-{2-(dimethylamino)ethoxy}ethyl]-N-methylethanolamine, and N-[2-{2-(diethylamino)ethoxy}ethyl],N-ethylethanolamine. Of these, from the viewpoints of availability and production costs, the alkanolamine is preferably at least one selected from the group consisting of ethanolamine, N-(2-aminoethyl)ethanolamine, and 2-(2-aminoethoxy)ethanol.

[0056] In the present invention, specific examples of the propylenediamines include 1,3-bis(dimethylamino)propane and 1,3-bis(diethylamino)propane.

[0057] In the present invention, specific examples of the piperazines include 1-(2-hydroxyethyl)-4-methylpiperazine, 1-(2,3-dihydroxypropyl)-4-methylpiperazine, 1-(2,3-dihydroxypropyl)-4-ethylpiperazine, 1-(2,3-dihydroxypropyl)-4-propylpiperazine, 1-(2,3-dihydroxypropyl)-4-butylpiperazine, 1-(2-hydroxy-3-methoxypropyl)-4-methylpiperazine, 1-(2-hydroxy-3-methoxypropyl)-4-methylpiperazine, propyl)-4-ethylpiperazine, 1-(2-hydroxy-3-methoxypropyl)-4-propylpiperazine, 1-(2-hydroxy-3-methoxypropyl)-4-butylpiperazine, 1-(2,3-dimethoxypropyl)-4-methylpiperazine, 1-(2,3-dimethoxypropyl)-4-ethylpiperazine, 1-(2,3-dimethoxypropyl)-4-propylpiperazine, 1-(2,3-dimethoxypropyl)-4-butylpiperazine, or 1,4-diazabicyclo[2.2.2]octane.

[0058] In the present invention, specific examples of the piperidines include piperidine, 2-methylpiperidine, 1-(2,3-dihydroxypropyl)-piperidine, 1-(2,3-dihydroxypropyl)-4-methylpiperidine, 1-(2,3-dihydroxypropyl)-4-ethylpiperidine, 1-(2,3-dihydroxypropyl)-4-propylpiperidine, 1-(2,3-dihydroxypropyl)-4-butylpiperidine, 1-(2-hydroxy-3-methoxypropyl)-piperidine, 1-(2-hydroxy-3-methoxypropyl)-4-methylpiperidine, Examples thereof include lysine, 1-(2-hydroxy-3-methoxypropyl)-4-ethylpiperidine, 1-(2-hydroxy-3-methoxypropyl)-4-propylpiperidine, 1-(2-hydroxy-3-methoxypropyl)-4-butylpiperidine, 1-(2,3-dimethoxypropyl)-piperidine, 1-(2,3-dimethoxypropyl)-4-methylpiperidine, 1-(2,3-dimethoxypropyl)-4-ethylpiperidine, 1-(2,3-dimethoxypropyl)-4-propylpiperidine, and 1-(2,3-dimethoxypropyl)-4-butylpiperidine.

[0059] In the present invention, specific examples of the morpholines include morpholine, 2-methylmorpholine, 2,6-dimethylmorpholine, 1-(2,3-dihydroxypropyl)-morpholine, 1-(2-hydroxy-3-methoxypropyl)-morpholine, and 1-(2,3-dimethoxypropyl)-morpholine.

[0060] In the present invention, specific examples of pyrrolidines include pyrrolidine, 2-methylpyrrolidine, 2,5-dimethylpyrrolidine, 1-(2,3-dihydroxypropyl)-pyrrolidine, 1-(2-hydroxy-3-methoxypropyl)-pyrrolidine, 1-(2,3-dimethoxypropyl)-pyrrolidine, and 1,5-diazabicyclo[4.3.0]-5-nonene.

[0061] In the present invention, specific examples of the azepanes include azepane, 2-methylazepane, 2,7-dimethylazepane, and 1,8-diazabicyclo[5.4.0]-7-undecene.

[0062] In the present invention, specific examples of the polyethylene polyamines include diethylenetriamine (DETA), triethylenetetramine (TETA), tetraethylenepentamine (TEPA), pentaethylenehexamine (PEHA), hexaethyleneheptamine (HEHA), and polyethylene polyamines having eight or more amino groups.

[0063] Here, the above-mentioned "TETA" refers to a compound in which four amino groups are connected in a linear or branched manner via an ethylene chain, but in the present invention, it also includes compounds having four amino groups and a piperazine ring structure. Specific compound names of TETA include, for example, 1,4,7,10-tetraazadecane, N,N-bis(2-aminoethyl)-1,2-ethanediamine, 1-[2-[(2-aminoethyl)amino]ethyl]-piperazine, and 1,4-bis(2-aminoethyl)-piperazine.

[0064] The term "TEPA" refers to a compound in which five amino groups are connected in a linear or branched fashion via an ethylene chain, but in the present invention, it also includes compounds having five amino groups and a piperazine ring structure. Specific examples of TEPA compounds include 1,4,7,10,13-pentaazatridecane, N,N,N'-tris(2-aminoethyl)-1,2-ethanediamine, 1-[2-[2-[2-[(2-aminoethyl)amino]ethyl]amino]ethyl]piperazine, 1-[2-[bis(2-aminoethyl)amino]ethyl]piperazine, and bis[2-(1-piperazinyl)ethyl]amine.

[0065] Furthermore, the above-mentioned "PEHA" refers to a compound in which six amino groups are connected in a linear or branched manner via an ethylene chain, but in the present invention, it also includes compounds that similarly have six amino groups and also have a piperazine ring structure. Specific examples of PEHA compounds include 1,4,7,10,13,16-hexaazahexadecane, N,N,N',N'-tetrakis(2-aminoethyl)-1,2-ethanediamine, N,N-bis(2-aminoethyl)-N'-[2-[(2-aminoethyl)amino]ethyl]-1,2-ethanediamine, 1-[2-[2-[2-[2-[2-[(2-aminoethyl)amino]ethyl]amino]ethyl]amino]ethyl]-piperazine, 1-[2-[2-[2-[bis(2-aminoethyl)amino]ethyl]amino]ethyl]piperazine, and N,N'-bis[2-(1-piperazinyl)ethyl]-1,2-ethanediamine.

[0066] The term "HEHA" refers to a compound in which seven amino groups are connected in a linear or branched fashion via an ethylene chain, but in the present invention, it also includes compounds having seven amino groups and a piperazine ring structure. Specific examples of HEHA compounds include 1,4,7,10,13,16,19-heptaazanonadecane, N-[2-[(2-aminoethyl)amino]ethyl]-N,N',N'-tris(2-aminoethyl)-1,2-ethanediamine, 1-[2-[2-[2-[2-[2-[2-[(2-aminoethyl)amino]ethyl]amino]ethyl]amino]ethyl]piperazine, and N-(2-aminoethyl)-N,N'-bis[2-(1-piperazinyl)ethyl]-1,2-ethanediamine.

[0067] The "polyethylene polyamine having eight or more amino groups" refers to a compound in which eight or more amino groups are connected in a linear or branched manner via an ethylene chain, but in the present invention, it also includes compounds which similarly have eight or more amino groups and also have a piperazine ring structure. Specific examples of polyethylene polyamines having eight or more amino groups include those under the trade name "Poly8" (manufactured by Tosoh Corporation) and polyethyleneimine.

[0068] Among these, from the viewpoint of availability and acquisition cost, diethylenetriamine (DETA) is preferred as polyethylene polyamines. triethylenetetramine (TETA), which consists of a mixture of 1,4,7,10-tetraazadecane, N,N-bis(2-aminoethyl)-1,2-ethanediamine, 1-[2-[(2-aminoethyl)amino]ethyl]-piperazine, and 1,4-bis(2-aminoethyl)-piperazine; tetraethylenepentamine (TEPA), which consists of a mixture of 1,4,7,10,13-pentaazatridecane, N,N,N'-tris(2-aminoethyl)-1,2-ethanediamine, 1-[2-[2-[2-[(2-aminoethyl)amino]ethyl]amino]ethyl]-piperazine, 1-[2-[bis(2-aminoethyl)amino]ethyl]-piperazine, and bis[2-(1-piperazinyl)ethyl]amine; pentaethylenehexamine (PEHA) consisting of a mixture of 1,4,7,10,13,16-hexaazahexadecane, N,N,N',N'-tetrakis(2-aminoethyl)-1,2-ethanediamine, N,N-bis(2-aminoethyl)-N'-[2-[(2-aminoethyl)amino]ethyl]-1,2-ethanediamine, 1-[2-[2-[2-[2-[(2-aminoethyl)amino]ethyl]amino]ethyl]amino]ethyl]-piperazine, 1-[2-[2-[2-[bis(2-aminoethyl)amino]ethyl]amino]ethyl]piperazine, and N,N'-bis[2-(1-piperazinyl)ethyl]-1,2-ethanediamine, Hexaethyleneheptamine (HEHA) consisting of a mixture of 1,4,7,10,13,16,19-heptaazanonadecane, N-[2-[(2-aminoethyl)amino]ethyl]-N,N',N'-tris(2-aminoethyl)-1,2-ethanediamine, 1-[2-[2-[2-[2-[2-[2-[(2-aminoethyl)amino]ethyl]amino]ethyl]amino]ethyl]-piperazine, and N-(2-aminoethyl)-N,N'-bis[2-(1-piperazinyl)ethyl]-1,2-ethanediamine, and Polyethylene polyamine with 8 or more amino groups, trade name "Poly8" (manufactured by Tosoh Corporation) It is preferable that the polymer is at least one selected from the group consisting of:

[0069] In the present invention, the amine compound (3) may be a commercially available product or may be synthesized by a known method, and is not particularly limited. The purity of the amine compound (3) is not particularly limited, but is preferably 95% or higher, and particularly preferably 99% or higher. If the purity is lower than 95%, the amount of carbon dioxide absorbed may decrease.

[0070] In the present invention, when the carbon dioxide separation composition contains amine compound (3), the weight of amine compound (3) relative to the total weight of the amine compounds (1) and (2) and amine compound (3) is not particularly limited, but from the viewpoint of increasing the amount of carbon dioxide absorbed per unit weight, it is preferably 50% by weight or less, more preferably 30% by weight or less, and even more preferably 20% by weight or less.

[0071] The carbon dioxide separation composition of the present invention can be used as is for its intended purpose, but from the viewpoint of operability, it can also be used as a composition further containing a solvent. The solvent used in the carbon dioxide separation composition is not particularly limited, and examples thereof include water, alcohol compounds, and polyol compounds (e.g., ethylene glycol, glycerin, and polyethylene glycol, but are not particularly limited thereto), and mixtures of these may also be used. Of these, water is preferred because it is highly efficient in absorbing and separating carbon dioxide gas as bicarbonate, is excellent in suppressing increases in the viscosity of absorbents and separating agents and the generation of solids, and does not significantly increase the carbon dioxide emission energy.

[0072] When the above-mentioned solvent (e.g., water) is used, the concentration of the solvent is preferably 30 to 95% by weight, and more preferably 50 to 80% by weight, based on the total amount of the carbon dioxide separation composition including the solvent, in order to improve the operability of the carbon dioxide separation composition of the present invention.

[0073] Next, the carbon dioxide separation method of the present invention will be described.

[0074] The carbon dioxide separation method of the present invention is characterized by comprising a step of contacting a gas containing carbon dioxide with the carbon dioxide separation composition of the present invention to highly selectively absorb carbon dioxide into the carbon dioxide separation composition. After the carbon dioxide has been absorbed in this manner, the method may also comprise a step of heating and / or reducing the pressure of the carbon dioxide separation composition to release the absorbed carbon dioxide.

[0075] In the carbon dioxide separation method of the present invention, the method for contacting a carbon dioxide-containing gas with the carbon dioxide separation composition of the present invention is not particularly limited, and known methods can be used, such as a bubbling method and a head-on contact method using a packed column or a plate column.

[0076] In the carbon dioxide separation method of the present invention, the temperature at which a gas containing carbon dioxide is absorbed into the carbon dioxide separation composition of the present invention is not particularly limited, but can usually be in the range of 10°C to 60°C.

[0077] Furthermore, the carbon dioxide separating composition of the present invention can be used in a carbon dioxide chemical absorption method by supporting or impregnating it on any carrier and forming a carbon dioxide absorbing / releasing agent.

[0078] The chemical absorption method involves bringing the carbon dioxide separation composition into contact with a gas containing carbon dioxide to absorb the carbon dioxide, and then dissipating the absorbed carbon dioxide by increasing the temperature or reducing the pressure. In this chemical absorption method, the temperature at which carbon dioxide is dissipated is generally 100°C or higher, but when the carbon dioxide separation composition of the present invention is used, there are no particular restrictions on the temperature, and temperatures below 100°C may be used.

[0079] The carrier is not particularly limited, but examples thereof include silica, alumina, magnesia, porous glass, activated carbon, polymethyl methacrylate-based porous resin, and fibers.

[0080] The silica may be crystalline or non-crystalline (amorphous), and many types are known, such as zeolite-like silica having fine pores, mesoporous silica, etc. There are no particular restrictions on the silica that can be used in the carbon dioxide absorption and desorption agent of the present invention, and any silica that is commercially available can be used, but silica with a large surface area is preferred.

[0081] The carbon dioxide absorbing / desorbing agent using the carrier of the present invention may further contain water.

[0082] The amount of the carbon dioxide separation composition supported in the carbon dioxide absorption / desorption agent using the carrier of the present invention is preferably 5 to 70 wt %, more preferably 10 to 60 wt %, of the weight of the carrier on which the carbon dioxide separation composition is supported, in terms of excellent carbon dioxide absorption capacity and ease of supporting the carbon dioxide separation composition.

[0083] The amount of water contained in the carbon dioxide absorption / desorption agent using the carrier of the present invention is preferably equal to or more than the moles of carbon dioxide to be absorbed. When the amount of water is equal to or more than the moles of carbon dioxide, the energy of carbon dioxide emission is not too large, which is preferable.

[0084] The carbon dioxide absorption / desorption agent using the carrier of the present invention can be applied to a carbon dioxide separation method widely known as a solid absorption method. The solid absorption method refers to a method in which a carbon dioxide separating agent is brought into contact with a gas containing carbon dioxide to absorb the carbon dioxide, and then the absorbed carbon dioxide is desorbed by heating or reducing the pressure. In the solid absorption method, the temperature at which carbon dioxide is desorbed is generally 100°C or higher, but when the carbon dioxide separating composition of the present invention is used, there are no particular restrictions on the temperature, and it may be below 100°C.

[0085] The carbon dioxide-containing gas may be pure carbon dioxide gas or a mixed gas containing carbon dioxide and other gases, such as, but not limited to, air, nitrogen, oxygen, hydrogen, argon, neon, helium, carbon monoxide, water vapor, methane, or nitrogen oxides.

[0086] There are no particular restrictions on the mixed gas that can be applied to the carbon dioxide separation method of the present invention, as long as it is a mixed gas that contains carbon dioxide. However, in order to improve the separation performance between carbon dioxide and other gases, it is preferable that the carbon dioxide concentration is 0.5% or more, and more preferably 1% or more.

[0087] In the carbon dioxide separation method of the present invention, there is no problem if additional steps other than the above steps (absorption step and diffusion step) are carried out. For example, a cooling step, a heating step, a washing step, an extraction step, an ultrasonic treatment step, a distillation step, or other steps of treating with chemicals can be carried out as appropriate.

[0088] The carbon dioxide separation method of the present invention is not particularly limited, and can be applied to, for example, carbon dioxide separation in a carbon monoxide production facility that produces carbon monoxide from fossil fuels or a hydrogen production facility that produces hydrogen from coal gasification gas. The method can also be applied to carbon dioxide recovery facilities from combustion exhaust gas generated in thermal power plants, steel plants, cement factories, and the like, which release gas into the atmosphere after carbon dioxide removal. [Example]

[0089] The present invention will be described below using examples, but the present invention is not limited to these. The carbon dioxide concentration meter used was RSIR-2000 manufactured by J Science Lab Co., Ltd.

[0090] [Example 1] 30 g of 1,4-diazabicyclo[2.2.2]octane-2-methanol (manufactured by Tosoh Corporation), 10 g of piperazine (manufactured by Tokyo Chemical Industry Co., Ltd.), and 60 g of pure water were mixed and stirred to obtain a carbon dioxide separation composition (100 g). The weight ratio of amine compound (1) to amine compound (2) was 100 parts by weight / 33.3 parts by weight. The water content of the carbon dioxide separation composition was 60% by weight. This was placed in a 200 mL gas absorption bottle and the temperature was adjusted to 50°C in a water bath. A mixed gas of carbon dioxide gas and nitrogen gas (carbon dioxide concentration: 2.0% by volume) was blown into the carbon dioxide separation composition through the gas inlet of the gas absorption bottle at a rate of 10 mL / min. The carbon dioxide concentration of the released gas was continuously measured using a carbon dioxide concentration meter for the mixed gas released from the gas outlet. 30 minutes after the start of blowing, the carbon dioxide concentration of the released gas was 0.005% by volume. After one hour it was 0.064% by volume, and after one and a half hours it was 0.158% by volume.

[0091] [Example 2] 32.6 g of 1,4-diazabicyclo[2,2,2]octane-2-methanol (manufactured by Tosoh Corporation), 7.4 g of piperazine (manufactured by Tokyo Chemical Industry Co., Ltd.), and 60 g of pure water were mixed and stirred to obtain a carbon dioxide separation composition (100 g). The weight ratio of amine compound (1) to amine compound (2) was 100 parts by weight / 22.7 parts by weight. The water content in the carbon dioxide separation composition was 60% by weight. The carbon dioxide separation composition was subjected to the same procedure as in Example 1 to measure the carbon dioxide concentration of the released gas. The carbon dioxide concentration of the released gas 30 minutes after the start of blowing was 0.003% by volume. After one hour, it was 0.048% by volume, and after one and a half hours, it was 0.166% by volume.

[0092] [Comparative Example 1] 30 g of N-methyldiethanolamine (Tokyo Chemical Industry Co., Ltd.), 10 g of piperazine (Tokyo Chemical Industry Co., Ltd.), and 60 g of pure water were mixed and stirred to obtain a carbon dioxide separation composition (100 g). The carbon dioxide separation composition was subjected to the same procedure as in Example 1 to measure the carbon dioxide concentration of the released gas. The carbon dioxide concentration of the released gas 30 minutes after the start of blowing was 0.031 vol%. After 1 hour, it was 0.076 vol%, and after 1.5 hours, it was 0.168 vol%.

[0093] Comparative Example 2 32.6 g of N-methyldiethanolamine (Tokyo Chemical Industry Co., Ltd.), 7.4 g of piperazine (Tokyo Chemical Industry Co., Ltd.), and 60 g of pure water were mixed and stirred to obtain a carbon dioxide separation composition (100 g). The carbon dioxide separation composition was subjected to the same procedure as in Example 1 to measure the carbon dioxide concentration of the released gas. The carbon dioxide concentration of the released gas 30 minutes after the start of blowing was 0.055% by volume. After one hour, it was 0.159% by volume, and after one and a half hours, it was 0.333% by volume.

[0094] The results of Example 1, Example 2, Comparative Example 1, and Comparative Example 2 are shown in the table below.

[0095] [Table 1]

Claims

1. The following formula 【Chemical 1】 1,4-diazabicyclo[2.2.2]octane-2-methanol (hereinafter referred to as "amine compound (1)") represented by the formula: The following formula 【Chemistry 2】 and water, wherein the concentration of the water is 30 to 95% by weight of the entire composition for carbon dioxide separation containing water.

2. The composition for carbon dioxide separation according to claim 1, wherein the composition ratio of the amine compound (1) to the amine compound (2) is 5 to 100 parts by weight of the amine compound (2) relative to 100 parts by weight of the amine compound (1).

3. 3. The carbon dioxide separation composition according to claim 1 or 2, further comprising, in addition to the amine compound (1) and the amine compound (2), at least one amine compound (3) selected from the group consisting of alkanolamines, propylenediamines, piperazines, piperidines, morpholines, pyrrolidines, azepanes, and polyethylenepolyamines (excluding the amine compounds (1) and (2)).

4. A method for separating carbon dioxide, comprising the step of contacting a gas containing carbon dioxide with the carbon dioxide separation composition according to any one of claims 1 to 3 to absorb the carbon dioxide in the gas containing carbon dioxide.

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