Carbon dioxide absorption liquid and method for capturing carbon dioxide from fuel gas

Abstract

The present invention relates to the technical field of carbon dioxide gas separation, and discloses a carbon dioxide absorbing liquid, and a method and device for capturing carbon dioxide from a fuel gas. The carbon dioxide absorbing liquid contains 100 parts by weight of a solvent, 10 to 55 parts by weight of an amino acid, 20 to 65 parts by weight of an organic amine, 5 to 15 parts by weight of an activator, and 2 to 12 parts by weight of a promoter. Due to the synergistic action of the amino acid, the organic amine, the activator, and the promoter, the carbon dioxide absorbing liquid according to the present invention not only improves the absorption capacity of the carbon dioxide absorbing liquid for carbon dioxide, but also reduces the energy consumption for regenerating the carbon dioxide absorbing liquid, and can obtain high-purity carbon dioxide.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of Chinese Patent Application No. 202111237906.1, filed on October 22, 2021, the contents of which are incorporated herein by reference. [Technical Field]

[0002] The present invention relates to the technical field of carbon dioxide gas separation, and more particularly to a carbon dioxide absorbing liquid and a method for capturing carbon dioxide from fuel gas. [Background technology]

[0003] As environmental problems in China and around the world become more serious, curbing greenhouse gas emissions has become a focus of the international community, with curbing CO2 emissions and reducing greenhouse gas emissions in particular becoming important and urgent issues.

[0004] A large amount of carbon dioxide is generated during the production of fuel gases such as oil field associated gas, PSA regeneration gas, biomethane gas, and biodegradation gas. Removing carbon dioxide from these gases plays an important role in reducing greenhouse gas emissions, improving energy quality, and utilizing them in the chemical industry.

[0005] Currently, CO2 capture methods include chemical absorption, adsorption, membrane separation, membrane absorption, and cryogenic distillation, with chemical absorption being the most widely used. However, chemical absorption generally has drawbacks, such as low carbon dioxide adsorption capacity, high energy consumption for regenerating the absorption solution, insufficient capture efficiency for strongly acidic raw gases, and difficulty in separating high-purity carbon dioxide.

[0006] Therefore, there is an urgent need to provide a carbon dioxide absorbing solution that has a large carbon dioxide adsorption capacity, requires little energy for regeneration, can be used to treat strongly acidic raw material gases, and can produce high-purity carbon dioxide. Summary of the Invention [Problem to be solved by the invention]

[0007] An object of the present invention is to solve the technical problems present in the chemical absorption method, such as a small carbon dioxide adsorption capacity, a large amount of energy consumption for regenerating the absorption solution, an insufficient effect of capturing strongly acidic feed gas, and difficulty in separating high-purity carbon dioxide, and to provide a carbon dioxide absorption solution and a method for capturing carbon dioxide from fuel gas. [Means for solving the problem]

[0008] In order to achieve the above object, a first aspect of the present invention is a method for producing a polymerizable composition comprising: 100 parts by weight of a solvent; 10 to 55 parts by weight of an amino acid; 20 to 65 parts by weight of an organic amine; 5 to 15 parts by weight of an activator; and 2 to 12 parts by weight of an accelerator; The carbon dioxide absorbing liquid includes an activator I and an activator II, wherein the activator I is at least one selected from the group consisting of alkyl quaternary ammonium-based ionic liquids, alkyl quaternary phosphonium-based ionic liquids, and pyridine-based ionic liquids, and the activator II is at least one selected from the group consisting of bisamino quaternary phosphonium-based ionic liquids, amino-functionalized imidazole-based ionic liquids, bisamino-functionalized ionic liquids, amino acid-based ionic liquids, tetramethylguanidine succinate-based ionic liquids, tetramethylguanidine dodecanedicarboxylate-based ionic liquids, and tetramethylguanidine polyethylene glycol dicarboxylate-based ionic liquids.

[0009] A second aspect of the present invention is Step (1) of passing a fuel gas and a lean liquid selected from the carbon dioxide absorption liquid according to the first aspect of the present invention through a porous membrane to perform mass transfer by indirect contact, thereby obtaining a rich liquid and a purified fuel gas; Step (2) of regenerating the rich liquid to obtain a regenerated barren liquid and a regenerated gas; and returning the regenerated barren liquid to step (1) as barren liquid. [Effects of the Invention]

[0010] According to the above technical solutions, the beneficial technical effects of the present invention are as follows: 1) The carbon dioxide absorbing solution according to the present invention not only improves the absorption capacity of the carbon dioxide absorbing solution for carbon dioxide due to the synergistic action of the amino acid, organic amine, activator, and accelerator, but also reduces the energy consumption for regenerating the carbon dioxide absorbing solution, making it possible to obtain high-purity carbon dioxide. 2) When the carbon dioxide absorption solution according to the present invention contains activator I and activator II, the amount of amino acid used can be increased, and due to the synergistic effect with a specific amount of organic amine used, the carbon dioxide removal rate can be further increased, the energy consumption for regeneration can be reduced, and a high-purity regenerated gas can be obtained. 3) By rationally adjusting the mass ratio of activator I to activator II in the carbon dioxide absorption solution according to the present invention, the carbon dioxide capture effect of the decarbonization solvent can be further improved, the energy consumption for regeneration can be reduced, and high-purity carbon dioxide can be obtained. 4) The method for capturing carbon dioxide from fuel gas according to the present invention can enhance the carbon dioxide capture effect through the synergistic action of the porous membrane and a specific barren liquid, thereby producing clean purified fuel gas with a carbon dioxide content (dry basis) of less than 3v%. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a schematic diagram of an apparatus for capturing carbon dioxide from fuel gas in the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0012] The endpoints of ranges and any values ​​disclosed herein should be understood not to be limited to the exact range or value, but to include values ​​close to those ranges or values. In the case of numerical ranges, the values ​​between the endpoints of each range, the values ​​between the endpoints of each range and the individual point values, and the values ​​between the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, and these numerical ranges should be considered to be specifically disclosed herein.

[0013] A first aspect of the present invention is a composition containing 100 parts by weight of a solvent, 10 to 55 parts by weight of an amino acid, 20 to 65 parts by weight of an organic amine, 5 to 15 parts by weight of an activator, and 2 to 12 parts by weight of an accelerator, the activator includes activator I and activator II, and the activator I is at least one selected from the group consisting of alkyl quaternary ammonium ionic liquids, alkyl quaternary phosphonium ionic liquids, and pyridine ionic liquids; The carbon dioxide absorbing liquid provided herein is one in which the activator II is at least one selected from the group consisting of bisamino quaternary phosphonium ionic liquids, amino-functionalized imidazole ionic liquids, bisamino-functionalized ionic liquids, amino acid ionic liquids, tetramethylguanidine succinate ionic liquids, tetramethylguanidine dodecanedicarboxylate ionic liquids, and tetramethylguanidine polyethylene glycol dicarboxylate ionic liquids.

[0014] In a preferred embodiment, the carbon dioxide absorbing liquid contains 100 parts by weight of a solvent, 15 to 35 parts by weight, preferably 30 to 35 parts by weight of an amino acid, 25 to 50 parts by weight, preferably 45 to 50 parts by weight of an organic amine, 6 to 10 parts by weight, preferably 5 to 10 parts by weight of an activator, and 3 to 5 parts by weight, preferably 4 to 5 parts by weight of a promoter.

[0015] In the present invention, when the amounts of the amino acid, organic amine, activator, accelerator, and solvent used are limited to the above ranges, the carbon dioxide capture effect of the carbon dioxide absorbing solution is better.

[0016] In a preferred embodiment, the mass ratio of the amino acid to the organic amine is 0.5 to 1:1, preferably 0.6 to 0.8:1.

[0017] The absorbents commonly used in the field of carbon dioxide capture are organic amines or amino acid salts, or organic amines with a small amount of amino acid added. However, in the present invention, the inventors have conducted research and found that by simultaneously using an amino acid, an organic amine, an activator, and a promoter, and by using activators I and II as activators, the amount of amino acid used can be increased, and the synergistic effect of the specific amounts of amino acid and organic amine used can further improve the carbon dioxide removal rate, reduce energy consumption for regeneration, and produce high-purity regenerated gas.

[0018] In a preferred embodiment, the amino acid is at least one selected from glycine, sarcosine, lysine, alanine, glutamic acid, serine, aminoacetic acid, proline, arginine, and histidine, and preferably one of glycine, sarcosine, lysine, and alanine.

[0019] In a preferred embodiment, the organic amine is at least one selected from N-methylmonoethanolamine (MMEA), 2-amino-2-methyl-1-propanol (AMP), N-methyldiethanolamine (MDEA), monoethanolamine (MEA), diethanolamine (DEA), diisopropanolamine (DIPA), isopropylaminoethanol (IPAE), hydroxyethylpiperazine (HEPZ), morpholine (MOR), 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) and derivatives thereof, preferably at least one of N-methylmonoethanolamine, 2-amino-2-methyl-1-propanol, and N-methyldiethanolamine.

[0020] In a preferred embodiment, the mass ratio of the activator I to the activator II is 1:1-8.5, preferably 1:2.5-5.

[0021] In the present invention, by rationally adjusting the mass ratio of activator I to activator II, the carbon dioxide capture effect of the decarbonization solvent can be further improved, the energy consumption for regeneration can be reduced, and high-purity carbon dioxide can be obtained.

[0022] In a preferred embodiment, the alkyl quaternary ammonium-based ionic liquid, alkyl quaternary phosphonium-based ionic liquid, and pyridine-based ionic liquid are not particularly limited in the present invention, and all of the alkyl quaternary ammonium-based ionic liquids, alkyl quaternary phosphonium-based ionic liquids, and pyridine-based ionic liquids commonly used in this field can be used in the present invention.

[0023] In a preferred embodiment, the activator I is an alkylphosphonium tetrafluoroborate ([PR x H 4-x ] + [BF4] - ), alkylammonium hexafluorophosphate ([NR x H 4-x ] + [PF6] - ), alkylpyridinium aluminum chloride salts ([RPy] + [AlCl4] - ) wherein x is an integer of 1 to 4, R is alkyl having 1 to 20 carbon atoms, preferably alkyl having 6 to 16 carbon atoms, and x Rs may be the same or different and each independently may be, for example, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tetradecyl, or hexadecyl. More preferably, the activator I is one selected from trihexyl(tetradecyl)phosphonium tetrafluoroborate, hexadecyltrimethylammonium hexafluorophosphate, and cetylpyridinium chloride.

[0024] In a preferred embodiment, the activator II is 3-propylamino-tributylphosphonium glycine salt ([aP 4443 ][Gly]), 3-propylamino-tributylphosphonium alanine salt ([aP 4443 ][Ala]), glycine tetraethylammonium ([N 2222 ][Gly]), glycine tetrabutylammonium ([N 4444 ][Gly]), glycine tetrabutylphosphonium [P4444 ][Gly], 1-aminopropyl-3-methylimidazole glycine salt ([APmim][Gly]), 3-propylamino-tributylphosphonium-2-hydroxypyridine ([aP 4443 [2-Op]), and more preferably, the activator II is at least one selected from [P 4444 ][Gly], [aP 4443 ][2-Op], [aP 4443 [Gly].

[0025] In a preferred embodiment, the accelerator is selected from sodium chloride and / or potassium chloride, preferably sodium chloride.

[0026] In a preferred embodiment, the solvent in said absorption liquid is selected from water.

[0027] A second aspect of the present invention is Step (1) of passing a fuel gas and a lean liquid selected from the carbon dioxide absorption liquid according to the first aspect of the present invention through a porous membrane to perform mass transfer by indirect contact, thereby obtaining a rich liquid and a purified fuel gas; Step (2) of regenerating the rich liquid to obtain a regenerated barren liquid and a regenerated gas; and step (3) of returning the regenerated barren liquid to step (1) as barren liquid.

[0028] In step (1), In a preferred embodiment, the fuel gas is selected from strongly acidic fuel gases, and the carbon dioxide content (on a dry basis) in the strongly acidic fuel gas is 15 to 60v%, preferably 25 to 50v%.

[0029] In a preferred embodiment, the strongly acidic fuel gas is at least one selected from oil field associated gas, PSA regeneration gas, biomethane gas, and biodegradation gas.

[0030] Here, the PSA regeneration gas is the pressure swing adsorption regeneration gas in this field. The method for capturing carbon dioxide from fuel gas according to the present invention is not particularly limited to any particular fuel gas, and is particularly applicable to treating strongly acidic fuel gases with a carbon dioxide content (dry basis) of 15% by volume or more.

[0031] In a preferred embodiment, the flow ratio of the fuel gas to the absorption liquid is 1 Nm 3 / h: 10 to 80 L / h, preferably 1 Nm 3 / h:20~50L / h.

[0032] In a preferred embodiment, the porous membrane is selected from pressure-resistant porous membranes, preferably hollow fiber membranes, and the hollow fiber membranes have an inner diameter of 40 to 60 mm, preferably 45 to 55 mm, and an outer diameter of 0.5 to 1.2 mm, preferably 0.8 to 0.9 mm.

[0033] In a preferred embodiment, the operating conditions for the mass transfer by indirect contact include a mass transfer temperature of 25 to 80°C, preferably 35 to 50°C, and a mass transfer pressure of 1.0 to 20.0 MPa, preferably 4.0 to 16.0 MPa.

[0034] In a preferred embodiment, the carbon dioxide content (dry basis) in the purified fuel gas is less than 3v%, preferably 1.5 to 2.5v%.

[0035] The method for capturing carbon dioxide from fuel gas according to the present invention further enhances the carbon dioxide capture effect by combining the porous membrane with a specific barren liquid, and can obtain purified fuel gas with a carbon dioxide content (dry basis) of less than 3v%, which meets industrial production standards.

[0036] In step (2), In a preferred embodiment, the regeneration of the rich solution in the present invention is not particularly limited and can be performed according to a general operation in this field. For example, the rich solution is sent to a regeneration tower for regeneration.

[0037] In a preferred embodiment, the carbon dioxide content (dry basis) in the regeneration gas is 95v% or more, preferably 98v% or more, and more preferably 99.5v% or more.

[0038] In the present invention, the regeneration gas obtained by regeneration may contain a small amount of water in addition to carbon dioxide, and water may be further removed from the regeneration gas to obtain a high-purity regeneration gas. In the present invention, the method for removing water from the regeneration gas is not particularly limited and can be carried out according to common procedures in this field. For example, the regeneration gas may be condensed to remove water.

[0039] In a preferred embodiment, the energy consumption for regeneration in the regeneration is 1.8 to 2.9 × 10 3 kcal / Nm 3 CO2, preferably 1.8 to 2.1 × 10 3 kcal / Nm 3 It's CO2.

[0040] In step (3), In a preferred embodiment, the regenerated barren solution is heat exchanged with the rich solution and returned to step (1).

[0041] In the present invention, if the temperature of the regenerated barren liquid is still high after heat exchange with the rich liquid, making it difficult to satisfy the operating conditions for mass transfer by indirect contact, the temperature of the regenerated barren liquid after heat exchange is further lowered.

[0042] The present invention will be described in detail below with reference to examples. Below, examples and comparative examples are carried out using the apparatus shown in Figure 1, which includes a membrane absorber 1, a heat exchanger 2, a regeneration tower 3, a lean liquid cooler 4, a lean liquid pump 5, and a fuel gas storage tank 6, where the rich liquid outlet of the membrane absorber 1 is sequentially connected to the heat exchanger 2 and the top of the regeneration tower 3, the bottom of the regeneration tower 3 is sequentially connected to the heat exchanger 2, the lean liquid pump 5, the lean liquid cooler 4, and the lean liquid inlet of the membrane absorber 1, and the fuel gas storage tank 6 is connected to the membrane absorber 1.

[0043] The membrane absorber 1 is a membrane absorber including a hollow fiber membrane, manufactured by the Dalian Institute of Chemical Physics, Chinese Academy of Sciences. The CO2 content (dry basis) is measured by a flue gas analyzer, and the energy consumption for regeneration is the regeneration heat amount / CO2 yield, where the regeneration heat amount is kcal and the CO2 yield is Nm 3 is. Example 1

[0044] (1) 2.0 Nm from fuel gas storage tank 6 3 1 / h of simulated strongly acidic fuel gas (CO2 content (dry basis) was 40v%, balance gas was N2) and 40 L / h of barren liquid (composition shown in Table 1) were introduced into membrane absorber 1, and the simulated strongly acidic fuel gas and barren liquid were flowed on both sides of the hollow fiber membrane, respectively, and passed through the hollow fiber membrane under conditions of 40°C and 8.0 MPa, causing mass transfer by indirect contact to obtain rich liquid and purified fuel gas. (2) The rich liquid was introduced into the regeneration tower 3 for regeneration, and regenerated lean liquid was obtained from the bottom of the regeneration tower, and then regenerated gas was obtained from the top of the regeneration tower 3. (3) First, the regenerated barren liquid was heat exchanged with the rich liquid from the membrane absorber 1 in the heat exchanger 2, and then cooled in the barren liquid cooler 4 by the barren liquid pump 5, and returned to the membrane absorber 1 as the barren liquid. The CO2 content (dry basis) in the purified fuel gas obtained was 1.8v%, the purity of CO2 in the regenerated gas obtained was 99.5% or more (dry basis), and the energy consumption for regeneration was 2.1 × 10 3 kcal / Nm 3 It was CO2. Example 2

[0045] The barren solution was different and the composition of the barren solution in Example 2 was the same as in Example 1, except as shown in Table 1. Here, the CO2 content (dry basis) in the purified fuel gas obtained was 1.5v%, the purity of CO2 in the regenerated gas obtained was 99.5% or more (dry basis), and the energy consumption for regeneration was 1.8 × 10 3 kcal / Nm 3 It was CO2. Example 3

[0046] The barren solution was different and the composition of the barren solution in Example 3 was the same as in Example 1, except as shown in Table 1. The CO2 content (dry basis) in the purified fuel gas obtained was 2.0v%, the purity of CO2 in the regenerated gas obtained was 99.5% or more (dry basis), and the energy consumption for regeneration was 2.3 × 10 3 kcal / Nm 3 It was CO2. Example 4

[0047] The operating conditions for the simulated strongly acidic fuel gas and the indirect contact mass transfer were different. The carbon dioxide content (dry basis) in the simulated strongly acidic fuel gas in Example 4 was 50% by volume, the N2 content was 50% by volume, and the indirect contact mass transfer was carried out using a hollow fiber membrane at 40°C and 16.0 MPa, which was the same as in Example 1. The CO2 content (dry basis) in the purified fuel gas obtained was 2.3v%, the purity of CO2 in the regenerated gas obtained was 99.5% or more (dry basis), and the energy consumption for regeneration was 2.6 × 10 3 kcal / Nm 3 It was CO2. Example 5

[0048] The barren solution was different and the composition of the barren solution in Example 5 was the same as in Example 4, except as shown in Table 1. The CO2 content (dry basis) in the purified fuel gas obtained was 2.1v%, the purity of CO2 in the regenerated gas obtained was 99.5% or more (dry basis), and the energy consumption for regeneration was 2.3 × 10 3 kcal / Nm 3 It was CO2. Example 6

[0049] The barren solution was different and the composition of the barren solution in Example 6 was the same as in Example 4, except as shown in Table 1. The CO2 content (dry basis) in the purified fuel gas obtained was 2.5v%, the purity of CO2 in the regenerated gas obtained was 99.5% or more (dry basis), and the energy consumption for regeneration was 2.5 x 10 3 kcal / Nm 3It was CO2. Example 7

[0050] The barren solution was different and the composition of the barren solution in Example 7 was the same as in Example 4, except as shown in Table 1. The CO2 content (dry basis) in the purified fuel gas obtained was 3.0v%, the purity of CO2 in the regenerated gas obtained was 99.5% or more (dry basis), and the energy consumption for regeneration was 2.7 × 10 3 kcal / Nm 3 It was CO2. Example 8

[0051] The barren solution was different and the composition of the barren solution in Example 8 was the same as in Example 4, except as shown in Table 1. The CO2 content (dry basis) in the purified fuel gas obtained was 2.8v%, the purity of CO2 in the regenerated gas obtained was 99.5% or more (dry basis), and the energy consumption for regeneration was 2.9 × 10 3 kcal / Nm 3 It was CO2. Comparative Example 1

[0052] The barren solution was different and the composition of the barren solution in Comparative Example 1 was the same as in Example 1, except as shown in Table 1. The CO2 content (dry basis) in the purified fuel gas obtained was 2.9v%, the purity of CO2 in the regenerated gas obtained was 90% (dry basis), and the energy consumption for regeneration was 3.2 × 10 3 kcal / Nm 3 It was CO2. Comparative Example 2

[0053] The barren solution was different and the composition of the barren solution in Comparative Example 2 was the same as in Example 4, except that it is shown in Table 1. The CO2 content (dry basis) in the purified fuel gas obtained was 3.0v%, the purity of CO2 in the regenerated gas obtained was 88% (dry basis), and the energy consumption for regeneration was 3.7 × 10 3 kcal / Nm 3 It was CO2. Comparative Example 3

[0054] The barren solution was different and the composition of the barren solution in Comparative Example 3 was the same as in Example 4, except that it is shown in Table 1. The CO2 content (dry basis) in the purified fuel gas obtained was 3.1v%, the purity of CO2 in the regenerated gas obtained was 85% (dry basis), and the energy consumption for regeneration was 3.6 × 10 3 kcal / Nm 3 It was CO2. Comparative Example 4

[0055] The barren solution was different and the composition of the barren solution in Comparative Example 4 was the same as in Example 4, except that it is shown in Table 1. The CO2 content (dry basis) in the purified fuel gas obtained was 3.0v%, the purity of CO2 in the regenerated gas obtained was 90% (dry basis), and the energy consumption for regeneration was 3.9 × 10 3 kcal / Nm 3 It was CO2. Comparison of Example 4, Comparative Example 3, and Comparative Example 4 revealed that using too much or too little amino acid and organic amine is detrimental to improving carbon dioxide absorption capacity and reducing energy consumption for regeneration. Comparative Example 5

[0056] The barren solution was different and the composition of the barren solution in Comparative Example 5 was the same as in Example 4, except that it is shown in Table 1. The CO2 content (dry basis) in the purified fuel gas obtained was 3.2v%, the purity of CO2 in the regenerated gas obtained was 99% (dry basis), and the energy consumption for regeneration was 3.7 × 10 3 kcal / Nm 3 It was CO2. Comparison of Example 4 and Comparative Example 5 revealed that changing the amino acid to an amino acid salt was disadvantageous in terms of reducing the energy consumption for regeneration and improving the carbon dioxide absorption effect. Comparative Example 6

[0057] The barren solution was different and the composition of the barren solution in Comparative Example 6 was the same as in Example 4, except that it is shown in Table 1. The CO2 content (dry basis) in the purified fuel gas obtained was 2.3v%, the purity of CO2 in the regenerated gas obtained was 99% (dry basis), and the energy consumption for regeneration was 3.1 × 10 3 kcal / Nm 3 It was CO2. A comparison between Example 4 and Comparative Example 6 revealed that the synergistic effect of activator I and activator II enhances the carbon dioxide absorption effect, reduces the energy consumption for regenerating the carbon dioxide absorbing solution, and produces high-purity carbon dioxide. When only activator I was included but activator II was not, the energy consumption for regenerating carbon dioxide increased significantly, indicating that the desorption performance of the absorbing solution was poor. Comparative Example 7

[0058] The barren solution was different and the composition of the barren solution in Comparative Example 7 was the same as in Example 4, except that it is shown in Table 1. The CO2 content (dry basis) in the purified fuel gas obtained was 3.2v%, the purity of CO2 in the regenerated gas obtained was 99% (dry basis), and the energy consumption for regeneration was 2.6 × 10 3 kcal / Nm 3 It was CO2. Comparison of Example 4 and Comparative Example 7 revealed that when only activator II was included and activator I was not included, the absorption capacity of the carbon dioxide absorbing solution for carbon dioxide decreased, and the carbon dioxide content in the purified fuel gas was too high. Comparative Example 8

[0059] The barren solution was different and the composition of the barren solution of Comparative Example 8 is shown in Table 1, and was the same as in Example 4, except that Activator II was 1-butyl-3-methylimidazolium sodium phosphate. The CO2 content (dry basis) in the purified fuel gas obtained was 3.3v%, the purity of CO2 in the regenerated gas obtained was 86% (dry basis), and the energy consumption for regeneration was 2.8 × 10 3 kcal / Nm 3 It was CO2. Comparison of Example 4 and Comparative Example 8 revealed that when both 1-butyl-3-methylimidazolium sodium phosphate and trihexyl(tetradecyl)phosphonium tetrafluoroborate were used as activators, the carbon dioxide adsorption and separation effect was poor. Comparative Example 9

[0060] The barren solution was different and the composition of the barren solution in Comparative Example 9 was the same as in Example 4, except that it is shown in Table 1. The CO2 content (dry basis) in the purified fuel gas obtained was 3.4v%, the purity of CO2 in the regenerated gas obtained was 98.5% (dry basis), and the energy consumption for regeneration was 2.7 × 10 3 kcal / Nm 3 It was CO2. Comparison between Example 4 and Comparative Example 9 revealed that the addition of a promoter enhances the effect of adsorbing and separating carbon dioxide.

[0061] [Table 1] JPEG0007752242000002.jpg190169

[0062] Although the preferred embodiments of the present invention have been described in detail above, the present invention is not limited thereto. Within the scope of the technical concept of the present invention, the technical solution of the present invention may be modified in a number of simple ways, including combining each technical feature in other suitable ways, and these simple modifications and combinations should also be considered as the disclosed content of the present invention, and all fall within the protection scope of the present invention. [Explanation of symbols]

[0063] 1. Membrane absorber 2 Heat exchanger 3 Regeneration Tower 4 Poor liquid cooler 5. Lean Liquid Pump 6. Fuel gas storage tanks

Claims

1. The composition comprises 100 parts by weight of a solvent, 10 to 55 parts by weight of an amino acid, 20 to 65 parts by weight of an organic amine, 5 to 15 parts by weight of an activator, and 2 to 12 parts by weight of an accelerator; the activator includes activator I and activator II, and the activator I is at least one selected from the group consisting of alkyl quaternary ammonium ionic liquids, alkyl quaternary phosphonium ionic liquids, and pyridine ionic liquids; the activator II is an amino acid-based ionic liquid; The carbon dioxide absorbing liquid, wherein the promoter is sodium chloride and / or potassium chloride.

2. 2. The carbon dioxide absorbing solution according to claim 1, comprising: 100 parts by weight of a solvent; 15 to 35 parts by weight of an amino acid; 25 to 50 parts by weight of an organic amine; 6 to 10 parts by weight of an activator; and 3 to 5 parts by weight of a promoter.

3. The carbon dioxide absorbing solution according to claim 2, comprising: 100 parts by weight of a solvent; 30 to 35 parts by weight of an amino acid; 45 to 50 parts by weight of an organic amine; 5 to 10 parts by weight of an activator; and 4 to 5 parts by weight of a promoter.

4. The carbon dioxide absorbing solution according to claim 1, wherein the amino acid is at least one selected from the group consisting of glycine, sarcosine, lysine, alanine, glutamic acid, serine, aminoacetic acid, proline, arginine, and histidine.

5. The carbon dioxide absorbing solution according to claim 4, wherein the amino acid is one of glycine, sarcosine, lysine, and alanine.

6. The carbon dioxide absorbing solution according to claim 1, wherein the organic amine is at least one selected from the group consisting of N-methylmonoethanolamine, 2-amino-2-methyl-1-propanol, N-methyldiethanolamine, monoethanolamine, diethanolamine, diisopropanolamine, isopropylaminoethanol, hydroxyethylpiperazine, morpholine, 1,8-diazabicyclo[5.4.0]undec-7-ene, and derivatives thereof.

7. The carbon dioxide absorbing solution according to claim 6, wherein the organic amine is at least one selected from N-methylmonoethanolamine, 2-amino-2-methyl-1-propanol, and N-methyldiethanolamine.

8. The carbon dioxide absorbing solution according to claim 1, wherein the mass ratio of the amino acid to the organic amine is 0.5 to 1:

1.

9. The carbon dioxide absorbing solution according to claim 8, wherein the mass ratio of the amino acid to the organic amine is 0.6 to 0.8:

1.

10. The carbon dioxide absorbing solution according to claim 1, wherein the mass ratio of the activator I to the activator II is 1:1 to 8.

5.

11. The carbon dioxide absorbing solution according to claim 10, wherein the mass ratio of the activator I to the activator II is 1:2.5 to 1:

5.

12. The carbon dioxide absorbing solution according to claim 1, wherein the activator I is one selected from the group consisting of alkylphosphonium tetrafluoroborate, alkylammonium hexafluorophosphate, and alkylpyridinium aluminum chloride salt.

13. The carbon dioxide absorption liquid described in claim 1, wherein the activator I is one selected from trihexyl(tetradecyl)phosphonium tetrafluoroborate, tetramethylammonium tetrafluoroborate, and cetylpyridinium chloride.

14. The carbon dioxide absorbing solution according to claim 1, wherein the activator II is at least one selected from 3-propylamino-tributylphosphonium glycine salt, 3-propylamino-tributylphosphonium alanine salt, glycine tetraethylammonium, glycine tetrabutylammonium, glycine tetrabutylphosphonium, and 1-aminopropyl-3-methylimidazole glycine salt.

15. The carbon dioxide absorption liquid of claim 1, wherein the solvent is selected from water.

16. 1. A method for capturing carbon dioxide from a fuel gas, comprising: A step (1) of passing a fuel gas and a lean liquid selected from the carbon dioxide absorption liquid according to any one of claims 1 to 14 through a porous membrane to perform mass transfer by indirect contact, thereby obtaining a rich liquid and a purified fuel gas; Step (2) of regenerating the rich liquid to obtain a regenerated barren liquid and a regenerated gas; and step (3) returning the regenerated barren solution to step (1) as a barren solution.

17. 17. The method according to claim 16, wherein the fuel gas is selected from strongly acidic fuel gases, and the carbon dioxide content (dry basis) in the strongly acidic fuel gas is 15 to 60 v %.

18. 18. The method according to claim 17, wherein the carbon dioxide content (dry basis) in the strongly acidic fuel gas is 25 to 50 v %.

19. The method according to claim 17, wherein the strongly acidic fuel gas is at least one selected from oil field associated gas, PSA regeneration gas, biomethane gas, and biodegradation gas.

20. The flow rate ratio of the fuel gas to the absorption liquid is 1 Nm ３ / h: 10 to 80 L / h.

21. The flow rate ratio of the fuel gas to the absorption liquid is 1 Nm ３ / h: 20 to 50 L / h.

22. 17. The method of claim 16, wherein the porous membrane is a hollow fiber membrane.

23. 17. The method of claim 16, wherein the operating conditions for the indirect contact mass transfer include a mass transfer temperature of 25-80°C and a mass transfer pressure of 1-20 MPa.

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