Amine composition for carbon dioxide separation

Abstract

To provide an amine composition with a carbon dioxide emission rate that is excellent compared to a known composition in order to solve such a conventional problem that a carbon dioxide absorption liquid of which an adsorption rate is improved by adding a diamine compound to N-methyldiethanolamine has a low carbon dioxide emission rate.SOLUTION: A composition for carbon dioxide separation contains; at least one kind of amine compound (A) selected from a group comprising an amine compound represented by a general formula (1), an amine compound represented by a general formula (2), and an amine compound represented by the following general formula (5); and at least one kind of amine compound (B) selected from a group comprising an amine compound represented by a general formula (3), and an amine compound represented by a general formula (4).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] In recent years, due to the issue of global warming, carbon dioxide separation and capture has attracted attention, and the development of carbon dioxide absorbents has been actively pursued.

[0003] The combustion exhaust gas from thermal power plants and cement kilns, where carbon dioxide separation and capture equipment is installed, often contains NOx (nitrogen oxides).In this case, the NOx in the combustion exhaust gas is absorbed by an absorption solution in the carbon dioxide capture system, producing nitrous acid (HNO2) and other compounds.

[0004] In contrast, aqueous monoethanolamine solutions (Patent Document 1) and aqueous 2-isopropylaminoethanol solutions (Patent Document 2) are commonly used as carbon dioxide absorbing liquids. These amines contain primary and secondary amines, and the primary amines react with nitrous acid to produce alcohols, while the secondary amines react with nitrous acid to produce nitrosamines. As a result, the carbon dioxide absorption performance of the primary and secondary amines decreases (Patent Document 3).

[0005] R-NH2+ HNO2→ ROH + N2+ H2O ··· (1) R 1 R 2 NH + HNO2 → R 1 R 2 N-NO + HO (2) For this reason, carbon dioxide absorbing solutions containing only tertiary amines have also been developed, for example, N-methyldiethanolamine (Patent Documents 4 and 5).

[0006] On the other hand, N-methyldiethanolamine has the problem of low absorption rate. For this reason, carbon dioxide absorbing liquids have been developed that improve absorption rate by adding diamine compounds such as N-methyl-1,3-diaminopropane to N-methyldiethanolamine (Patent Document 6). [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Publication No. 6-343858 [Patent Document 2] Japanese Patent Application Publication No. 2019-115888 [Patent Document 3] Japanese Patent Application Laid-Open No. 2013-202523 [Patent Document 4] Special Publication No. 2006-528062 [Patent Document 5] Special Publication No. 2013-517925 [Patent Document 6] Special Publication No. 2009-539595 Summary of the Invention [Problem to be solved by the invention]

[0008] A carbon dioxide absorbing solution in which a diamine compound is added to N-methyldiethanolamine to improve the absorption rate has a problem of a low carbon dioxide emission rate. The present invention has been made in view of the above problem, and an object of the present invention is to provide an amine composition having a carbon dioxide emission rate superior to that of known compositions. [Means for solving the problem]

[0009] As a result of intensive research to solve the above problems, the present inventors have found that the composition described below has a superior carbon dioxide emission rate compared to a carbon dioxide absorbing solution in which a diamine compound is added to N-methyldiethanolamine to improve the absorption rate, and have thus completed the present invention.

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

[0011] [1] A composition for carbon dioxide separation, comprising at least one amine compound (A) selected from the group consisting of amine compounds represented by the following general formula (1), amine compounds represented by the following general formula (2), and amine compounds represented by the following general formula (5), and at least one amine compound (B) selected from the group consisting of amine compounds represented by the following general formula (3), and amine compounds represented by the following general formula (4):

[0012] [ka]

[0013] [In the above formula, 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. 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 formula, R 2 and R 3 each independently represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms.

[0016] [ka]

[0017] [In the above formula, R 4 represents 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. 7 each independently represents an alkylene group having 1 to 4 carbon atoms.

[0018] [ka]

[0019] [In the above formula, R 4 and R 5 each independently represents 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 6 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 6 may be bonded to each other to form a ring. R 7 represents an alkylene group having 1 to 4 carbon atoms.

[0020] [ka]

[0021] [In the above formula, R 6 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 7 each independently represents an alkylene group having 1 to 4 carbon atoms. [2] The amine compound represented by the general formula (1) is represented by the following formula:

[0022] [ka]

[0023] 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:

[0024] [3] The amine compound represented by the general formula (2) is represented by the following formula:

[0025] [ka]

[0026] The carbon dioxide separation composition according to [1], characterized in that it is 1-(2,3-dihydroxypropyl)-piperazine represented by the following formula:

[0027] [4] The amine compound represented by the general formula (5) is represented by the following formula:

[0028] [ka]

[0029] The carbon dioxide separation composition according to [1], characterized in that it is N-methyldiethanolamine represented by the following formula:

[0030] [5] The carbon dioxide separation composition according to any one of [1] to [4], wherein the amine compound represented by the general formula (3) is N,N-dimethyl-1,3-diaminopropane or N,N-dimethyl-1,2-diaminoethane.

[0031] [6] A composition for carbon dioxide separation according to any one of [1] to [4], characterized in that the amine compound represented by the general formula (4) is N-(2-aminoethyl)-2-aminoethanol or 2-(3-aminopropyl)-2-aminoethanol.

[0032] [7] The carbon dioxide separation composition according to [1], characterized in that it contains at least one amine compound (A) selected from the group consisting of 1,4-diazabicyclo[2.2.2]octane-2-methanol, 1-(2,3-dihydroxypropyl)-piperazine, and N-methyldiethanolamine, and at least one amine compound (B) selected from the group consisting of N,N-dimethyl-1,3-diaminopropane, N,N-dimethyl-1,2-diaminoethane, N-(2-aminoethyl)-2-aminoethanol, and 2-(3-aminopropyl)-2-aminoethanol.

[0033] [8] The composition for carbon dioxide separation according to any one of [1] to [7] above, characterized in that the composition ratio of the amine compound (A) to the amine compound (B) is 5 to 300 parts by weight of the amine compound (B) per 100 parts by weight of the amine compound (A).

[0034] [9] The composition for carbon dioxide separation according to any one of [1] to [8] above, further comprising, in addition to the amine compound (A) and the amine compound (B), at least one amine compound (C) selected from the group consisting of alkanolamines, propylenediamines, piperazines, piperidines, morpholines, pyrrolidines, azepanes, and polyethylenepolyamines (excluding the amine compounds (A) and (B)).

[0035]

[10] A composition for carbon dioxide separation according to any one of [1] to [9] 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.

[0036]

[11] 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

[10] above, to absorb the carbon dioxide in the mixed gas. [Effects of the Invention]

[0037] The carbon dioxide separation composition of the present invention has a higher carbon dioxide emission rate per unit time than conventionally known materials, and has the effect of enabling a large amount of carbon dioxide to be absorbed and separated at high speed with a small amount of the carbon dioxide separation composition. Therefore, the present invention is extremely useful industrially in that it can efficiently absorb and separate carbon dioxide emitted in large amounts from large-scale thermal power plants and the like. DETAILED DESCRIPTION OF THE INVENTION

[0038] The present invention will be described in detail below.

[0039] First, the carbon dioxide separation composition of the present invention will be described.

[0040] The carbon dioxide separation composition of the present invention is characterized by containing at least one amine compound (A) selected from the group consisting of amine compounds represented by the above general formula (1), amine compounds represented by the above general formula (2), and amine compounds represented by the above general formula (5), and at least one amine compound (B) selected from the group consisting of amine compounds represented by the general formula (3) and amine compounds represented by the general formula (4).More specifically, for example, a more preferable carbon dioxide separation composition can be prepared by dissolving a mixture of the amine compound (A) and the amine compound (B) in a solvent such as water.

[0041] In the present invention, the amine compounds represented by the above general formulas (1), (2), (5), (3) and (4) all play a role in adsorbing and desorbing carbon dioxide.

[0042] 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.

[0043] In the present invention, R 10 , R 11 , R 12 , R 13 , and R 14 are 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 (an n-butyl group, an isobutyl group, a sec-butyl group, 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, and a sec-butoxy group. Among 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.

[0044] In the present invention, R in the above general formula (1) 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.

[0045] In addition, R in the above general formula (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 (an n-butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group), a methoxymethyl group, a methoxymethyl group, and a 2-hydroxyethyl group. Among 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, and a 2-hydroxyethyl group are preferred, and a hydrogen atom is more preferred.

[0046] a and b each independently represent 0 or 1, and satisfy the relationship a+b=1.

[0047] When a=1 and b=0, the above general formula (1) is represented by the following general formula (1a).

[0048] [ka]

[0049] [In the above formula, 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).

[0050] [ka]

[0051] [In the above formula, 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 represented by general formula (1) include the following compounds (exemplary compounds 1 to 28), but the present invention is not limited to these.

[0052] [ka]

[0053] The aforementioned R 10 , R 11 , R 12 , R 13 , R 14 , and R 15 With regard to the groups, it is preferable that they are each independently a hydrogen atom, a methyl group, an ethyl group, or a butyl group, and it is more preferable that they are each independently a hydrogen atom or a methyl group, in terms of excellent carbon dioxide diffusion efficiency (amount diffused / amount absorbed).

[0054] The aforementioned R 10 , R 11 , R 12 , R 13 , and R 14 is more preferably a hydrogen atom from the viewpoint of availability.

[0055] Regarding the amine compound represented by the above general formula (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) That is, the amine compounds represented by the following formula are preferred.

[0056] [ka]

[0057] In the above general formula (2) of the present invention, R 2 and R 3 each independently represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms.

[0058] The alkyl group having 1 to 4 carbon atoms is not particularly limited, but examples thereof include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, a cyclopropyl group, an n-butyl group, a sec-butyl group, an isobutyl group, a tert-butyl group, and a cyclobutyl group. 2 and R3 Regarding the groups, each independently is preferably a hydrogen atom or a methyl group, and more preferably a hydrogen atom, in terms of excellent carbon dioxide adsorption / desorption efficiency.

[0059] Regarding the amine compound represented by the above general formula (2), from the viewpoint of solubility, 1-(2,3-dihydroxypropyl)-piperazine (R 2 =R 3 = hydrogen atom). That is, an amine compound represented by the following formula is preferred.

[0060] [ka]

[0061] In the above general formula (5) of the present invention, R 4 represents 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. 7 each independently represents an alkylene group having 1 to 4 carbon atoms.

[0062] The alkyl group having 1 to 4 carbon atoms is not particularly limited, but examples thereof include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, a cyclopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a cyclobutyl group, and a tert-butyl group.

[0063] The aminoalkyl group having 3 to 4 carbon atoms is not particularly limited, but examples thereof include a 3-aminopropyl group, a 2-aminopropyl group, a 1-methyl-2-aminoethyl group, a 4-aminobutyl group, a 3-aminobutyl group, a 2-aminoethyl group, and a 1-methyl-3-aminopropyl group.

[0064] The hydroxyalkyl having 3 to 4 carbon atoms is not particularly limited, but examples thereof include a 3-hydroxypropyl group, a 2-hydroxypropyl group, a 1-methyl-2-hydroxyethyl group, a 4-hydroxybutyl group, a 3-hydroxybutyl group, a 2-hydroxyethyl group, and a 1-methyl-3-hydroxypropyl group.

[0065] The alkylene having 1 to 4 carbon atoms is not particularly limited, but examples thereof include methylene, 1,2-ethylene, 1,3-propylene, 1,2-propylene, 1,4-butene, 1,3-butene, and 1,2-butene.

[0066] R in general formula (5) 4 With regard to the group, in view of excellent carbon dioxide adsorption / desorption efficiency, a methyl group, an ethyl group, a 2-hydroxyethyl group, a 2-hydroxypropyl group, or a 3-aminopropyl group is preferred, and a methyl group is more preferred.

[0067] R in general formula (5) 7 Regarding the above, each of them is preferably 1,2-ethylene or 1,3-propylene, and more preferably 1,2-ethylene, in terms of excellent carbon dioxide adsorption / desorption efficiency.

[0068] The amine compound represented by the general formula (5) is preferably N-methyldiethanolamine from the viewpoint of solubility. That is, the amine compound represented by the following formula is preferred.

[0069] [ka]

[0070] R in the above general formula (3) of the present invention 4 and R 5 R each independently represents 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.6 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 6 may be bonded to each other to form a ring. 7 represents an alkylene group having 1 to 4 carbon atoms.

[0071] In general formula (3), the definitions and preferred ranges of the alkyl group having 1 to 4 carbon atoms, the aminoalkyl group having 3 to 4 carbon atoms, the hydroxyalkyl group having 3 to 4 carbon atoms, and the alkylene having 1 to 4 carbon atoms are the same as the definitions and preferred ranges of the alkyl group having 1 to 4 carbon atoms, the aminoalkyl group having 3 to 4 carbon atoms, the hydroxyalkyl group having 3 to 4 carbon atoms, and the alkylene having 1 to 4 carbon atoms shown in general formula (5).

[0072] R in general formula (3) 4 , and R 5 Regarding the groups, from the viewpoint of excellent carbon dioxide adsorption / desorption efficiency, it is preferable that each group is independently a methyl group, an ethyl group, a 2-hydroxyethyl group, a 2-hydroxypropyl group, or a 3-aminopropyl group, and it is more preferable that each group is a methyl group.

[0073] R in general formula (3) 6 With regard to the group, in view of excellent carbon dioxide adsorption / desorption efficiency, a methyl group, an ethyl group, a 2-hydroxyethyl group, a 2-hydroxypropyl group, or a 3-aminopropyl group is preferred, and a methyl group is more preferred.

[0074] R in general formula (3) 7 Regarding the carbon dioxide adsorption / desorption material, 1,2-ethylene or 1,3-propylene is preferred, and 1,2-ethylene is more preferred, in terms of excellent carbon dioxide adsorption / desorption efficiency.

[0075] In the amine compound represented by the general formula (3), R 4 and R 6The compounds bonded to each other to form a ring are not particularly limited, but examples thereof include amine compounds represented by the following general formula (3a), and preferred are amine compounds represented by the following general formula (3b) in terms of excellent carbon dioxide adsorption / desorption efficiency.

[0076] [ka]

[0077] [In the above formula, R 5 represents an alkyl group having 1 to 4 prime numbers, 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 7 each independently represents an alkylene group having 1 to 4 carbon atoms.

[0078] [ka]

[0079] [In the above formula, R 5 represents 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.] In the general formulae (3a) and (3b), the definitions and preferred ranges of the alkyl group having 1 to 4 carbon atoms, the aminoalkyl group having 3 to 4 carbon atoms, the hydroxyalkyl group having 3 to 4 carbon atoms, and the alkylene having 1 to 4 carbon atoms are the same as the definitions and preferred ranges of the alkyl group having 1 to 4 carbon atoms, the aminoalkyl group having 3 to 4 carbon atoms, the hydroxyalkyl group having 3 to 4 carbon atoms, and the alkylene having 1 to 4 carbon atoms shown in the general formula (5).

[0080] R in general formula (3a) 5 and R 7 The preferred range of R 5 and R 7 The preferred range is the same as that of

[0081] R in general formula (3b) 5 The preferred range of R 5 The preferred range is the same as that of

[0082] Specific examples of the amine compound represented by the general formula (3) include N,N-dimethyl-1,4-diaminobutane, N,N-dimethyl-1,3-diaminopropane, N,N-dimethyl-1,2-diaminopropane, N,N-dimethyl-1,2-diaminoethane, N,N-diethyl-1,4-diaminobutane, N,N-diethyl-1,3-diaminopropane, N,N-diethyl-1,2-diaminopropane, and N,N-diethyl-1,2 -diaminoethane, N,N-dipropyl-1,4-diaminobutane, N,N-dipropyl-1,3-diaminopropane, N,N-dipropyl-1,2-diaminopropane, N,N-dipropyl-1,2-diaminoethane, N-methylpiperazine, N-ethylpiperazine, N-(2-hydroxyethyl)piperazine, N-(2-hydroxypropyl)piperazine, or N-(3-aminopropyl)piperazine.

[0083] Regarding the amine compound represented by the general formula (3), from the viewpoint of availability, N,N-dimethyl-1,3-diaminopropane (R 4 =R 5 Methyl group, R 6 = hydrogen atom, R 7 = 1,3-propylene), and N,N-dimethyl-1,2-diaminoethane (R 4 =R 5 Methyl group, R 6 = hydrogen atom, R 7 = 1,2-ethylene).

[0084] R in the above general formula (4) of the present invention 6 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. 7each independently represents an alkylene group having 1 to 4 carbon atoms.

[0085] In general formula (4), the definitions and preferred ranges of the alkyl group having 1 to 4 carbon atoms, the aminoalkyl group having 3 to 4 carbon atoms, the hydroxyalkyl group having 3 to 4 carbon atoms, and the alkylene having 1 to 4 carbon atoms are the same as the definitions and preferred ranges of the alkyl group having 1 to 4 carbon atoms, the aminoalkyl group having 3 to 4 carbon atoms, the hydroxyalkyl group having 3 to 4 carbon atoms, and the alkylene having 1 to 4 carbon atoms shown in general formula (5).

[0086] R in general formula (4) 6 With regard to the group, in view of excellent carbon dioxide adsorption / desorption efficiency, a methyl group, an ethyl group, a 2-hydroxyethyl group, a 2-hydroxypropyl group, or a 3-aminopropyl group is preferred, and a methyl group is more preferred.

[0087] R in general formula (4) 7 Regarding the above, each of them is preferably 1,2-ethylene or 1,3-propylene, and more preferably 1,2-ethylene, in terms of excellent carbon dioxide adsorption / desorption efficiency.

[0088] Specific examples of the amine compound represented by general formula (4) include N-(2-aminoethyl)-2-aminoethanol, N-(3-aminopropyl)-2-aminoethanol, N-(2-aminopropyl)-2-aminoethanol, N-(4-aminobutyl)-2-aminoethanol, N-(2-aminoethyl)-3-aminopropanol, N-(3-aminopropyl)-3-aminopropanol, N-(2-aminopropyl)-3-aminopropanol, N-(4-aminobutyl)-3-aminopropanol, N-(2-aminoethyl)-4-aminobutanol, N-(3-aminopropyl)-4-aminobutanol, N-(2-aminopropyl)-4-aminobutanol, and N-(4-aminobutyl)-4-aminobutanol.

[0089] Regarding the amine compound represented by the general formula (4), N-(2-aminoethyl)-2-aminoethanol (R 6 = hydrogen atom, R 7 = ethylene), and 2-(3-aminopropyl)-2-aminoethanol (R 6 = hydrogen atom, R 7 It is preferable that the amine is at least one amine selected from the group consisting of 1,2-ethylene and 1,3-propylene.

[0090] The carbon dioxide separation composition of the present invention, which is characterized by containing at least one amine compound (A) selected from the group consisting of the amine compound represented by the general formula (1), the amine compound represented by the general formula (2), and the amine compound represented by the general formula (5), and at least one amine compound (B) selected from the group consisting of the amine compound represented by the general formula (3) and the amine compound represented by the general formula (4), is excellent in terms of the absorption rate and the desorption rate of carbon dioxide, and is characterized by the fact that it is 1,4-diazabicyclo[2.2.2]octanol. Preferably, the carbon dioxide separation composition is characterized by comprising at least one amine compound (A) selected from the group consisting of N,N-dimethyl-1,3-diaminopropane, N,N-dimethyl-1,2-diaminoethane, N-(2-aminoethyl)-2-aminoethanol, and 2-(3-aminopropyl)-2-aminoethanol.

[0091] In terms of a high carbon dioxide absorption rate, the carbon dioxide separation composition of the present invention preferably has a composition ratio of amine compound (A) to amine compound (B) of 5 to 300 parts by weight of amine compound (B) per 100 parts by weight of amine compound (A), more preferably 10 to 200 parts by weight of amine compound (B) per 100 parts by weight of amine compound (A), and even more preferably 15 to 150 parts by weight of amine compound (B) per 100 parts by weight of amine compound (A).

[0092] In the present invention, the amine compounds represented by the general formulas (1), (2), (5), (4), and (5) 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.

[0093] The carbon dioxide separation composition of the present invention may further contain, in addition to the amine compounds represented by general formulas (1), (2), (5), (3), and (4), at least one amine compound (C) different from these selected from the group consisting of alkanolamines, propylenediamines, piperazines, piperidines, morpholines, pyrrolidines, azepanes, and polyethylenepolyamines. The coexistence of the amine compound (C) 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.

[0094] 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. Among 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.

[0095] In the present invention, specific examples of the propylene diamines include 1,3-bis(dimethylamino)propane, 1,3-bis(diethylamino)propane, etc. Among these, from the viewpoints of availability and production costs, the following propylene diamines are preferred: In the present invention, specific examples of the piperazines include piperazine, 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-meth 1-(2-hydroxy-3-methoxypropyl)-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.

[0096] 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.

[0097] 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.

[0098] 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.

[0099] 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.

[0100] 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.

[0101] 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.

[0102] 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.

[0103] 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.

[0104] 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.

[0105] 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.

[0106] 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:

[0107] In the present invention, the amine compound (C) 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 (C) is not particularly limited, but is preferably 95% or more, and particularly preferably 99% or more. If the purity is less than 95%, the amount of carbon dioxide absorbed may decrease.

[0108] In the present invention, when the carbon dioxide separation composition contains an amine compound (C), the weight of the amine compound (C) relative to the total weight of the amine compounds (A) and (B) and the amine compound (C) 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.

[0109] 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.

[0110] 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.

[0111] Next, the carbon dioxide separation method of the present invention will be described.

[0112] 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 the carbon dioxide into the carbon dioxide separation composition, and may also comprise a step of, after such absorption, subjecting the carbon dioxide separation composition to elevated temperature and / or reduced pressure to release the absorbed carbon dioxide.

[0113] 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.

[0114] 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 0°C to 50°C.

[0115] In the carbon dioxide separation method of the present invention, the temperature at which carbon dioxide is released from the carbon dioxide separation composition of the present invention is not particularly limited, but is typically in the range of 60 to 150° C. However, from the viewpoint of energy saving, it is preferably 100° C. or lower.

[0116] 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.

[0117] 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.

[0118] The carrier is not particularly limited, but examples thereof include silica, alumina, magnesia, porous glass, activated carbon, polymethyl methacrylate-based porous resin, and fibers.

[0119] 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.

[0120] The carbon dioxide absorbing / desorbing agent using the carrier of the present invention may further contain water.

[0121] 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.

[0122] 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.

[0123] 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.

[0124] 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.

[0125] 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 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 5% or more, and more preferably 10% or more.

[0126] 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.

[0127] The carbon dioxide separation method of the present invention is not particularly limited, but can be applied to, for example, the separation of carbon dioxide (CO2) from combustion exhaust gas generated in thermal power plants, steel plants, cement factories, etc., and the separation of carbon dioxide (CO2) from steam reformed gas obtained in a steam reforming process. [Example]

[0128] The present invention will be described below using examples, but the present invention should not be construed as being limited to these examples.

[0129] [Example 1] 7 g of 1,4-diazabicyclo[2,2,2]octane-2-methanol (Tosoh Corporation), 32 g of 1-(2,3-dihydroxypropyl)-piperazine (Sigma-Aldrich Corporation), 6 g of N,N-dimethyl-1,3-diaminopropane (Tokyo Chemical Industry Co., Ltd.), and 55 g of purified water were mixed and stirred to obtain a carbon dioxide absorbing solution (100 g). This solution was placed in a 200 mL gas absorption bottle and the temperature was adjusted to 40 °C in a water bath. A mixture of carbon dioxide gas (140 mL / min) and nitrogen gas (560 mL / min) was blown into the carbon dioxide absorbing solution at a rate of 140 mL / min for 1.5 hours. The amount of carbon dioxide gas absorbed was measured using a gas flow meter and a carbon dioxide concentration meter. The amount of carbon dioxide gas absorbed was 5.65 L at standard conditions. In other words, 56.5 L of carbon dioxide was absorbed per 1 kg of the absorbing solution at standard conditions. The amount of carbon dioxide gas absorbed per unit time for 30 minutes immediately after the start of the mixed gas injection was 1442 mL / min per kg of absorbing liquid.

[0130] Next, the gas absorption bottle was placed in a 70°C water bath, and a mixture of carbon dioxide gas (140 mL / min) and nitrogen gas (560 mL / min) was blown in for 0.5 hours. The amount of carbon dioxide gas emitted was measured using a gas flow meter and a carbon dioxide concentration meter. The amount of carbon dioxide gas emitted was 0.76 L, converted to standard conditions. In other words, 7.6 L of carbon dioxide gas was emitted per 1 kg of absorption liquid under standard conditions. The amount of carbon dioxide gas emitted per unit time was 253 mL / min per 1 kg of absorption liquid.

[0131] [Example 2] 20 g of 1,4-diazabicyclo[2,2,2]octane-2-methanol (manufactured by Tosoh Corporation), 20 g of N-(2-aminoethyl)ethanolamine (manufactured by Tokyo Chemical Industry Co., Ltd.), and 60 g of pure water were mixed and stirred to obtain a carbon dioxide absorbing solution (100 g). Using this carbon dioxide absorbing solution, a carbon dioxide gas absorption and desorption operation was carried out under the same conditions as in Example 1. The amount of carbon dioxide gas absorbed was 6.82 L in standard conditions. That is, 68.2 L of carbon dioxide was absorbed under standard conditions per 1 kg of absorbing solution. Furthermore, the amount of carbon dioxide gas absorbed per unit time for 30 minutes immediately after the start of the mixed gas injection was 1733 mL / min per 1 kg of absorbing solution.

[0132] The amount of carbon dioxide gas emitted was 0.75 L under standard conditions. In other words, 7.5 L of carbon dioxide gas was emitted per 1 kg of absorption liquid under standard conditions. The amount of carbon dioxide gas emitted per unit time was 252 mL / min per 1 kg of absorption liquid.

[0133] [Example 3] 30 g of 1,4-diazabicyclo[2,2,2]octane-2-methanol (manufactured by Tosoh Corporation), 10 g of N-(2-aminoethyl)ethanolamine (manufactured by Tokyo Chemical Industry Co., Ltd.), and 60 g of pure water were mixed and stirred to obtain a carbon dioxide absorbing solution (100 g). Using this carbon dioxide absorbing solution, carbon dioxide gas absorption and desorption operations were carried out under the same conditions as in Example 1. The amount of carbon dioxide gas absorbed was 5.24 L in standard condition equivalent. That is, 52.4 L of carbon dioxide was absorbed under standard conditions per 1 kg of absorbing solution. Furthermore, the amount of carbon dioxide gas absorbed per unit time for 30 minutes immediately after the start of blowing the mixed gas was 1364 mL / min per 1 kg of absorbing solution.

[0134] The amount of carbon dioxide gas emitted was 1.00 L in standard conditions. In other words, 10.0 L of carbon dioxide gas was emitted per 1 kg of absorption liquid under standard conditions. The amount of carbon dioxide gas emitted per unit time was 333 mL / min per 1 kg of absorption liquid.

[0135] [Example 4] 25 g of 1,4-diazabicyclo[2,2,2]octane-2-methanol (manufactured by Tosoh Corporation), 15 g of N-(2-aminoethyl)ethanolamine (manufactured by Tokyo Chemical Industry Co., Ltd.), and 60 g of pure water were mixed and stirred to obtain a carbon dioxide absorbing solution (100 g). Using this carbon dioxide absorbing solution, carbon dioxide gas absorption and desorption operations were carried out under the same conditions as in Example 1. The amount of carbon dioxide gas absorbed was 5.90 L in standard condition equivalent. That is, 59.0 L of carbon dioxide was absorbed under standard conditions per 1 kg of absorbing solution. Furthermore, the amount of carbon dioxide gas absorbed per unit time for 30 minutes immediately after the start of blowing in the mixed gas was 1513 mL / min per 1 kg of absorbing solution.

[0136] The amount of carbon dioxide gas emitted was 0.94 L in standard conditions. In other words, 9.4 L of carbon dioxide gas was emitted per 1 kg of absorption liquid under standard conditions. The amount of carbon dioxide gas emitted per unit time was 312 mL / min per 1 kg of absorption liquid.

[0137] [Example 5] 15 g of 1,4-diazabicyclo[2,2,2]octane-2-methanol (manufactured by Tosoh Corporation), 25 g of N-(2-aminoethyl)ethanolamine (manufactured by Tokyo Chemical Industry Co., Ltd.), and 60 g of pure water were mixed and stirred to obtain a carbon dioxide absorbing solution (100 g). Using this carbon dioxide absorbing solution, carbon dioxide gas absorption and desorption operations were carried out under the same conditions as in Example 1. The amount of carbon dioxide gas absorbed was 7.73 L in standard condition equivalent. That is, 77.3 L of carbon dioxide was absorbed under standard conditions per 1 kg of absorbing solution. Furthermore, the amount of carbon dioxide gas absorbed per unit time for 30 minutes immediately after the start of blowing the mixed gas was 1991 mL / min per 1 kg of absorbing solution.

[0138] The amount of carbon dioxide gas emitted was 0.74 L in standard conditions. In other words, 7.4 L of carbon dioxide gas was emitted per 1 kg of absorption liquid under standard conditions. The amount of carbon dioxide gas emitted per unit time was 245 mL / min per 1 kg of absorption liquid.

[0139] [Example 6] 25 g of N-methyldiethanolamine (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.), 15 g of N-(2-aminoethyl)ethanolamine (manufactured by Tokyo Chemical Industry Co., Ltd.), and 60 g of pure water were mixed and stirred to obtain a carbon dioxide absorbing solution (100 g). Using this carbon dioxide absorbing solution, carbon dioxide gas absorption and desorption operations were carried out under the same conditions as in Example 1. The amount of carbon dioxide gas absorbed was 6.10 L converted to standard conditions. That is, 61.0 L of carbon dioxide was absorbed under standard conditions per 1 kg of absorbing solution. Furthermore, the amount of carbon dioxide gas absorbed per unit time for 30 minutes immediately after the start of blowing the mixed gas was 1374 mL / min per 1 kg of absorbing solution.

[0140] The amount of carbon dioxide gas emitted was 0.93 L in standard conditions. In other words, 9.30 L of carbon dioxide gas was emitted per 1 kg of absorption liquid under standard conditions. The amount of carbon dioxide gas emitted per unit time was 309 mL / min per 1 kg of absorption liquid.

[0141] [Comparative Example 1] 30 g of N-methyldiethanolamine (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) and 70 g of pure water were mixed and stirred to obtain a carbon dioxide absorbing solution (100 g). Using this carbon dioxide absorbing solution, carbon dioxide gas absorption and desorption operations were carried out under the same conditions as in Example 1. The amount of carbon dioxide gas absorbed was 3.15 L in terms of standard conditions. That is, 31.5 L of carbon dioxide was absorbed per 1 kg of absorbing solution under standard conditions. Furthermore, the amount of carbon dioxide gas absorbed per unit time for 30 minutes immediately after the start of blowing in the mixed gas was 540 mL / min per 1 kg of absorbing solution.

[0142] The amount of carbon dioxide gas emitted was 1.42 L under standard conditions. In other words, 14.2 L of carbon dioxide gas was emitted per 1 kg of absorption liquid under standard conditions. The amount of carbon dioxide gas emitted per unit time was 190 mL / min per 1 kg of absorption liquid.

[0143] Comparative Example 2 24 g of N-methyldiethanolamine (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.), 16 g of N-methyl-1,3-diaminopropane (manufactured by Tokyo Chemical Industry Co., Ltd.), and 60 g of pure water were mixed and stirred to obtain a carbon dioxide absorbing solution (100 g). Using this carbon dioxide absorbing solution, carbon dioxide gas absorption and desorption operations were carried out under the same conditions as in Example 1. The amount of carbon dioxide gas absorbed was 7.16 L converted to standard conditions. That is, 71.6 L of carbon dioxide was absorbed under standard conditions per 1 kg of absorbing solution. Furthermore, the amount of carbon dioxide gas absorbed per unit time for 30 minutes immediately after the start of blowing the mixed gas was 1742 mL / min per 1 kg of absorbing solution.

[0144] The amount of carbon dioxide gas emitted was 0.53 L under standard conditions. In other words, 5.30 L of carbon dioxide gas was emitted per 1 kg of absorption liquid under standard conditions. The amount of carbon dioxide gas emitted per unit time was 177 mL / min per 1 kg of absorption liquid.

[0145] Comparative Example 3 30 g of N,N-dimethyl-1,3-diaminopropane (manufactured by Tokyo Chemical Industry Co., Ltd.) and 70 g of pure water were mixed and stirred to obtain a carbon dioxide absorbing solution (100 g). Using this carbon dioxide absorbing solution, carbon dioxide gas absorption and desorption operations were carried out under the same conditions as in Example 1. The amount of carbon dioxide gas absorbed was 8.11 L converted to standard conditions. That is, 81.1 L of carbon dioxide was absorbed under standard conditions per 1 kg of absorbing solution. Furthermore, the amount of carbon dioxide gas absorbed per unit time for 30 minutes immediately after the start of blowing in the mixed gas was 2023 mL / min per 1 kg of absorbing solution.

[0146] The amount of carbon dioxide gas emitted was 0.94 L in standard conditions. In other words, 9.40 L of carbon dioxide gas was emitted per 1 kg of absorption liquid under standard conditions. The amount of carbon dioxide gas emitted per unit time was 141 mL / min per 1 kg of absorption liquid.

[0147] Comparative Example 4 40 g of N-(2-aminoethyl)ethanolamine (manufactured by Tokyo Chemical Industry Co., Ltd.) and 60 g of pure water were mixed and stirred to obtain a carbon dioxide absorbing solution (100 g). Using this carbon dioxide absorbing solution, a carbon dioxide gas absorption and desorption operation was carried out under the same conditions as in Example 1. The amount of carbon dioxide gas absorbed was 9.20 L converted to standard conditions. That is, 92.0 L of carbon dioxide was absorbed per 1 kg of absorbing solution under standard conditions. Furthermore, the amount of carbon dioxide gas absorbed per unit time for 30 minutes immediately after the start of blowing in the mixed gas was 2000 mL / min per 1 kg of absorbing solution.

[0148] The amount of carbon dioxide gas emitted was 0.63 L in standard conditions. In other words, 6.30 L of carbon dioxide gas was emitted per 1 kg of absorption liquid under standard conditions. The amount of carbon dioxide gas emitted per unit time was 209 mL / min per 1 kg of absorption liquid.

[0149] [Table 1]

[0150] [Table 2]

Claims

1. A composition for carbon dioxide separation, comprising: at least one amine compound (A) selected from the group consisting of 1,4-diazabicyclo[2.2.2]octane-2-methanol and 1-(2,3-dihydroxypropyl)-piperazine; at least one amine compound (B) selected from the group consisting of N,N-dimethyl-1,3-diaminopropane, N,N-dimethyl-1,2-diaminoethane, N-(2-aminoethyl)-2-aminoethanol, and 2-(3-aminopropyl)-2-aminoethanol; and water, or comprising amine compound (A) which is N-methyldiethanolamine; at least one amine compound (B) selected from the group consisting of N-(2-aminoethyl)-2-aminoethanol, and 2-(3-aminopropyl)-2-aminoethanol; 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. 2. The carbon dioxide separation composition according to claim 1, wherein the composition ratio of the amine compound (A) to the amine compound (B) is 5 to 300 parts by weight per 100 parts by weight of the amine compound (A).

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

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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