Co2 gas removal device, and co2 gas absorption liquid purification device used for the same

Abstract

To provide a CO2 gas removal device that can repeatedly use the acid component collection liquid for purifying the CO2 gas absorption liquid and a CO2 gas absorption liquid purification unit for use in the CO2 gas removal device.SOLUTION: A CO2 gas removal device is provided, comprising: a CO2 separation and recovery unit that absorbs and recovers processing-target gas containing CO2 gas by using the CO2 absorption liquid containing amine compounds; and a CO2 absorption liquid purification unit that purifies the CO2 absorption liquid through electrodialysis from the CO2 absorption liquid. The CO2 absorption liquid purification unit comprises: an electrodialysis unit that transfers the acid components contained in the CO2 absorption liquid into the acid component collection liquid for purification; an amine separation unit that separates the amine compounds from the acid component collection liquid; and an acid component separation unit that separates the acid components from the acid component collection liquid.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] An embodiment of the present invention relates to a CO2 gas removal device that removes CO2 gas contained in exhaust gas discharged from a factory or the like, and a CO2 gas absorbing liquid purification device that can purify a CO2 absorbing liquid used in the device. [Background technology]

[0002] In order to achieve the "2°C target" and "1.5°C ambitious target" for limiting global warming set out in the Paris Agreement, countries are being called upon to further accelerate their climate change measures. Carbon dioxide Capture, Utilization and Storage (CCUS) is expected to play a major role alongside hydrogen and renewable energy as a measure to reduce emissions of carbon dioxide (CO2), a gas with a large greenhouse effect.

[0003] Chemical absorption is one of the methods for capturing CO2. In the chemical absorption method, CO2-containing exhaust gas discharged from thermal power plants and steelworks is brought into contact with an aqueous solution (hereinafter referred to as the absorbing solution) containing basic compounds such as amino group-containing compounds (hereinafter referred to as amine compounds), and the CO2 is absorbed in the absorbing solution. In the chemical absorption method, the absorbing solution is repeatedly circulated between an absorption section, where the CO2 is absorbed in the absorbing solution, and a regeneration section, where the CO2 is released from the absorbing solution, to capture CO2. However, when absorbing CO2, acid components other than CO2 are also absorbed in the absorbing solution. These acid components, such as NOx and SOx, react with the amine compounds in the absorbing solution to generate impurities called heat stable amine salts (HSAS). In addition, the amine compounds may be decomposed or modified by heating to release CO2 in the capture section or by the reaction of the amine compounds with oxygen in the exhaust gas, promoting the formation of heat-stable amine salts. If heat-stable amine salts accumulate in the absorption solution, not only will the CO2 absorption efficiency of the absorption solution decrease, but they may also cause corrosion of the CO2 capture equipment, so it is desirable to remove the heat-stable amines from the absorption solution and suppress the formation of heat-stable amines.

[0004] One of the techniques for removing acid components that may form heat-stable amine salts is electrodialysis. In electrodialysis, an ion exchange unit, which is a laminate of ion exchange membranes, is sandwiched between electrodes from both ends and a voltage is applied. At this time, the absorbing liquid and an acid component collecting liquid (hereinafter sometimes referred to as the collecting liquid) are contacted via the ion exchange membrane or the like, and the acid components in the absorbing liquid are transferred to the collecting liquid, that is, the acid components are removed from the absorbing liquid. In this system, it is desired to efficiently remove the acid components in the absorbing liquid and to suppress the leakage of amine compounds into the collecting liquid. On the other hand, by removing the acid components from the absorbing liquid, the acid components accumulate in the collecting liquid. If the acid component concentration in the collecting liquid exceeds a certain level, the efficiency of removing the acid components from the absorbing liquid decreases. Therefore, it is necessary to maintain the acid concentration at an appropriate level by periodically replacing or diluting the collecting liquid, but as a result, there has been a problem in that a large amount of waste liquid of the collecting liquid is generated. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2012-210595 A [Patent Document 2] JP 2013-163168 A Summary of the Invention [Problem to be solved by the invention]

[0006] As described above, in a conventional CO2 separation and capture system, a method for removing acid components from an absorbing solution by electrodialysis generates a large amount of acid waste liquid of an acid component collection solution. Therefore, it is desired to make it possible to reuse the acid component collection solution repeatedly and to reduce the amount of acid waste liquid. [Means for solving the problem]

[0007] The CO2 gas removal device according to this embodiment has the following features: a CO2 separation and capture unit that brings a gas to be treated, which contains CO2 gas, into contact with a CO2 absorbing liquid containing an amine compound to absorb the CO2 gas, and further recovers the CO2 gas from the CO2 absorbing liquid that has absorbed the CO2 gas, regenerates the CO2 absorbing liquid, and reuses it as the CO2 absorbing liquid; A CO2 absorbing liquid purification unit that removes acid components from the CO2 absorbing liquid by electrodialysis to purify the CO2 absorbing liquid; A CO2 gas removal device comprising: The CO2 absorption liquid purification unit an electrodialysis unit including a deionization compartment, a concentration compartment, and a membrane selected from a cation exchange membrane, an anion exchange membrane, and a bipolar membrane, disposed between the deionization compartment and the concentration compartment, the electrodialysis unit purifying the CO2 absorbing liquid by dissolving the acid component from the CO2 absorbing liquid introduced into the deionization compartment into an acid component collecting liquid introduced into the concentration compartment; an amine separation unit for separating an amine compound contained in the acid component collection liquid; an acid component separation unit for separating the acid components contained in the acid component collection liquid; The electrodialysis unit, the amine separation unit and the acid component separation unit are connected so that the acid component collection liquid can be circulated.

[0008] In addition, the CO2 absorbing liquid refining unit according to this embodiment has the following features: an electrodialysis unit including a deionization compartment, a concentration compartment, and a membrane selected from a cation exchange membrane, an anion exchange membrane, or a bipolar membrane, disposed between a pair of opposing electrodes, the electrodialysis unit purifying the CO2 absorbing liquid by dissolving the acid component from the CO2 absorbing liquid containing the acid component introduced into the deionization compartment into an acid component collecting liquid introduced into the concentration compartment; an amine separation unit for separating amine compounds contained in the acid component collection liquid; an acid component separation unit for separating the acid components contained in the acid component collection liquid; The electrodialysis unit, the amine separation unit and the acid component separation unit are connected so that the acid component collection liquid can be circulated.

[0009] In addition, the CO2 gas removal method according to the present embodiment is a CO2 separation and capture method in which a gas to be treated containing CO2 gas is brought into contact with a CO2 absorbing liquid containing an amine compound to absorb the CO2 gas, and the CO2 gas is recovered from the CO2 absorbing liquid having absorbed the CO2 gas, and the CO2 absorbing liquid is regenerated and reused as the CO2 absorbing liquid, Purifying the CO2 absorbing liquid by transferring the acid component to the acid component collecting liquid by electrodialysis; Separating the amine-based compound contained in the acid component collection liquid; and Separating the acid components contained in the acid component collection liquid The present invention is characterized in that it comprises: Effect of the Invention

[0010] According to this embodiment, it becomes possible to repeatedly use the acid component collecting liquid for refining the CO2 gas absorbing liquid used in the CO2 gas removal device, and it becomes possible to reduce the amount of acid waste liquid. [Brief description of the drawings]

[0011] [Figure 1] FIG. 1 is a conceptual diagram of a CO2 gas removal device according to a first embodiment. [Diagram 2] FIG. 11 is a conceptual diagram of a CO2 gas removal device according to a second embodiment. [Diagram 3] FIG. 11 is a conceptual diagram of a CO2 gas removal device according to a third embodiment. [Figure 4] FIG. 13 is a conceptual diagram of a CO2 gas removal device according to a fourth embodiment. [Diagram 5] FIG. 13 is a conceptual diagram of a CO2 gas removal device according to a fifth embodiment. [Figure 6] FIG. 13 is a conceptual diagram of a CO2 gas removal device according to a sixth embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, an embodiment for carrying out the invention will be described.

[0013] (First embodiment) Fig. 1 is a conceptual diagram of a CO2 gas removal apparatus according to the first embodiment. As shown in Fig. 1, the CO2 gas removal apparatus 1 according to the embodiment includes a CO2 separation and capture unit 2 and a CO2 absorbing liquid purification unit 3.

[0014] The CO2 separation and capture unit 2 absorbs CO2 gas by contacting the gas to be treated containing CO2 gas with an absorbing liquid containing an amine compound in an absorption section, and then recovers CO2 gas from the absorbing liquid that has absorbed CO2 gas in a regeneration section, regenerates the absorbing liquid, and reuses it as a CO2 absorbing liquid. Therefore, the absorbing liquid circulates between the absorbing section and the regeneration section (neither shown) included in the CO2 separation and capture unit. Such a CO2 separation and capture unit 2 can be arbitrarily selected from commonly known CO2 separation and capture units.

[0015] The CO2 absorbing liquid refining unit 3 removes acid components from the absorbing liquid discharged from the CO2 separation capture unit 2, purifies the absorbing liquid, and discharges a part of the produced absorbing liquid to the CO2 separation capture unit 2. That is, a part of the absorbing liquid circulating inside the CO2 separation capture unit 2 flows into the CO2 absorbing liquid refining unit 3 through the absorbing liquid introduction line L1, and the purified absorbing liquid flows out to the CO2 separation capture unit 2 through the absorbing liquid discharge line L2. As a result, the CO2 separation capture unit 2 and the CO2 absorbing liquid refining unit 3 are connected so that the circulating liquid circulates between them.

[0016] The CO2 absorbing liquid refining unit 3 includes an electrodialysis unit 4, an amine separation unit 5, and an acid component collecting liquid separation unit 6.

[0017] The electrodialysis unit 4 comprises a pair of opposing electrodes 4a, a deionization compartment 4b and a concentration compartment 4c between them. A membrane 4d selected from a cation exchange membrane, an anion exchange membrane, and a bipolar membrane is disposed between the deionization compartment 4b and the concentration compartment 4c, so that the absorption liquid introduced into the deionization compartment and the acid component collection liquid introduced into the concentration compartment can be indirectly contacted with each other.

[0018] Although Figure 1 shows an electrodialysis unit having three deionization compartments and three concentration compartments, it is sufficient that there is one or more deionization compartments and one or more concentration compartments, and there may be two or four or more of each.

[0019] In the embodiment, a part or the whole of the absorbing liquid circulating in the CO2 separation and capture unit 2 is supplied to the CO2 absorbing liquid purification unit 3 via an absorbing liquid introduction line L1.

[0020] In the CO2 separation and capture unit, a gas containing CO2 (gas to be treated) is brought into contact with the absorbing liquid to capture CO2 in the absorbing liquid. The gas to be treated is, for example, combustion exhaust gas discharged from boilers and gas turbines of thermal power plants, process exhaust gas generated in steelworks, and combustion exhaust gas generated in waste incineration plants. The gas to be treated is preferably cooled in a cooler or the like, and then subjected to treatments such as desulfurization and denitrification before being supplied to the CO2 separation and capture unit. By subjecting the untreated gas to desulfurization and denitrification, it is possible to suppress the formation of heat-stable amine salts in the absorbing liquid, and the load on the CO2 absorbing liquid purification unit 3 can be reduced.

[0021] When the absorbing liquid absorbs CO2 in the gas to be treated, it produces carbonates (formula (1) below). At the same time, it also absorbs SOx, NOx, carbonyl sulfide, hydrogen cyanide, thiocyanic acid, thiosulfuric acid, and other inorganic acids contained in the gas to be treated, producing heat-stable amine salts (formula (2) below). At this time, oxygen contained in the gas to be treated reacts with the components of the absorbing liquid to produce organic acids, such as formic acid and acetic acid, in the absorbing liquid, which may then react with amine compounds to form heat-stable amine salts. R3N+CO2+H2O → R3NH2CO3···(1) R3N+HX → R3NHX (2)

[0022] Here, R represents hydrogen, a substituted or unsubstituted alkyl group (which may form a heterocycle), etc., and HX represents an acid component capable of forming a heat-stable amine salt, such as sulfuric acid or nitric acid. In this embodiment, the acid component refers to an acid compound capable of forming a heat-stable amine salt, other than CO2 or carbonic acid.

[0023] The absorbing liquid is preferably an aqueous solution containing an amine compound and water. (i) Primary amines such as monoethanolamine and 2-amino-2-methyl-1-propanol; (ii) secondary amines such as diethanolamine and 2-methylaminoethanol; (iii) tertiary amines such as triethanolamine and N-methyldiethanolamine; (iv) polyethylene polyamines such as ethylene diamine, triethylene diamine, and diethylene triamine; (v) cyclic amines such as piperazines, piperidines, and pyrrolidines; (vi) Polyamines such as xylylenediamine, (vii) Amino acids such as methylamino carboxylic acids These can be used alone or in combination of two or more.

[0024] The absorbing liquid is usually used as an aqueous solution containing 10 to 70% by weight of these amine compounds. In addition, the absorbing liquid may contain other compounds, such as a reaction accelerator, a nitrogen-containing compound for improving the absorption performance of acidic gases such as CO2, an anticorrosive agent for preventing corrosion of plant equipment, a defoaming agent for preventing foaming, an antioxidant for preventing deterioration of the absorbing liquid, and a pH adjuster, in any ratio as long as the effect of the absorbing liquid is not impaired.

[0025] The absorbent that has absorbed the CO2 gas is separated from the absorbed CO2 gas in a regeneration tower or the like that is generally arranged in a CO2 separation and capture unit, and is further purified by the electrodialysis unit according to the embodiment and is used repeatedly. However, since the generated heat-stable amine salt is not removed by a general CO2 separation and capture unit, the heat-stable amine salt tends to accumulate in the absorbent.

[0026] In this embodiment, a part or all of the absorbing solution can be purified by removing the heat-stable amine salt by performing electrodialysis treatment in the CO2 absorbing solution purification unit 3. The absorbing solution from which the acid component has been removed in the electrodialysis unit 3 is returned to the CO2 separation and capture unit again via the absorbing solution discharge line L2.

[0027] In the first embodiment, the CO2 absorbing liquid purification unit 3 includes an electrodialysis unit 4, an amine separation unit 5, and an acid component separation unit 6. The collected liquid flows between the devices by a pump (not shown) arranged at an arbitrary position. The electrodialysis unit 4 is supplied with the absorbing liquid from the absorbing liquid introduction line L1 and the collected liquid from the collected liquid introduction line L4, and the acid component of the heat-stable amine salt in the absorbing liquid can be removed by applying a voltage to the electrodes 4a at both ends of the electrodialysis unit 4. The electrodialysis unit includes, for example, an anode and a cathode at both ends, and a membrane 4d such as a cation exchange membrane, an anion exchange membrane, or a bipolar membrane is arranged between the desalting chamber 4b and the concentration chamber 4c.

[0028] As the cation exchange membrane, a polymer membrane having a cation exchange group that can pass cations and block the passage of anions is used. For example, a membrane made of a polymer having one or more of a sulfonic acid group, a carboxylic acid group, a phosphonic acid group, a sulfate ester group, and a phosphate ester group can be used. As a preferred cation exchange membrane, specifically, a known cation exchange membrane such as Neocepta CMX, Neocepta CMB (trade name, manufactured by Astom Corporation), Selemion CMV, Selemion CMD, Selemion CSO, and Selemion CMF (trade name, manufactured by AGC Engineering Co., Ltd.) can be used.

[0029] As the anion exchange membrane, a polymer membrane having an anion exchange group that can pass anions and block the passage of cations is used. For example, a membrane made of a polymer having a weakly basic functional group such as a primary amino group, a secondary amino group, or a tertiary amino group in addition to a strongly basic group of a quaternary ammonium group can be used. As a preferred anion exchange membrane, specifically, a known anion exchange membrane such as Neocepta AMX or Neocepta AHA (trade name, manufactured by Astom Co., Ltd.); Selemion AMV, Selemion AMT, Selemion DSV, Selemion ASV, or Selemion AHO (trade name, manufactured by AGC Engineering Co., Ltd.) can be used.

[0030] The bipolar membrane is a composite membrane in which an anion exchange membrane and a cation exchange membrane are laminated, and is arranged so that the anode side is the anion exchange membrane and the cathode side is the cation exchange membrane. When a voltage equal to or higher than the theoretical decomposition voltage of water is applied in the presence of water, water can be electrolyzed into hydrogen ions and hydroxide ions. As a preferred bipolar membrane, specifically, a known bipolar membrane such as Neocepta BP-1E (trade name, manufactured by Astom Corporation) can be used.

[0031] The collection liquid may be an aqueous solution having an electric resistance that allows electrodialysis, but it is more preferable to include a small amount of an acid component in the initial stage of operation, since the amount of amine that has moved to the collection liquid and can exist as a cation increases, thereby increasing the amount of amine recovered. Examples of the acid component that can be used include sulfuric acid, nitric acid, formic acid, and acetic acid. When the collection liquid is recycled, the acid components removed from the absorption liquid accumulate, so it is preferable to add an acid component to the collection liquid only in the initial stage of operation and not thereafter, since this can suppress the generation of unnecessary heat-stable amine salts and also reduce the amount of acid component used.

[0032] The absorbent discharged from the electrodialysis unit 4 is supplied to the amine separation unit 5 via an acid component absorbent discharge line L3. The amine separation unit 5 has a function of separating mainly amine compounds from the components contained in the absorbent. The method for separating the amine compounds is not particularly limited, but reverse osmosis, ultrafiltration, electrodialysis, ion exchange resins, etc. can be used.

[0033] The absorption liquid from which the amine compounds have been separated in the amine separation unit 5 is supplied to the acid component separation unit 6 via a connecting line L4. The acid component separation unit 5 has a function of separating mainly acidic components from among the components contained in the absorption liquid.

[0034] The method for removing the acid components from the collection liquid is not particularly limited, but a method of forming a salt with the acid components as a base and removing the neutralized salt can be used. For example, an alkaline compound having an alkali metal or an alkaline earth metal as a cation can be added to the collection liquid to generate a neutralized salt with the acid components in the collection liquid. By removing the neutralized salt, the acid components can be removed from the collection liquid. The alkaline compound can be added manually, but the CO2 removal device can also be further provided with an alkaline compound addition unit.

[0035] The neutralized salt formed can be removed by adding an alkaline compound, followed by cooling to a low temperature, for example, below 0°C, to reduce the solubility of the neutralized salt and precipitate it. Specific examples of alkaline compounds that can be added include KOH, NaOH, Ca(OH)2, and Mg(OH)2. Since the collected liquid may contain multiple types of acid components, such as inorganic acids derived from exhaust gas and organic acids derived from amine compounds, it is desirable to select an alkaline compound to be added according to the acid components present. For example, when the neutralized salt is potassium nitrate or sodium formate, its solubility and the soluble concentration in water calculated from the solubility are as shown in Table 1.

[0036] [Table 1]

[0037] The collected liquid produced by removing the acid components in the acid component separation unit 6 is introduced into the electrodialysis unit 4 via an acid component collected liquid introduction line L5 and reused for removing acidic components.

[0038] Second Embodiment 2 is a conceptual diagram of a CO2 gas removal apparatus according to a second embodiment. The main difference between this embodiment and the first embodiment is the order of the amine separation unit 5 and the acid component absorption liquid separation unit 6. In this embodiment, the solution is sent from the electrodialysis unit 4 to the acid component separation unit 6 to separate the acid, and then the amine compounds are separated by the amine separation unit 5. This embodiment is preferably employed in the method for separating amine compounds in the amine separation unit when the concentration of the acid components is first reduced and the amine compounds can be efficiently removed.

[0039] (Third embodiment) FIG. 3 is a conceptual diagram of a CO2 gas removal device according to a third embodiment. The main difference between this embodiment and the first embodiment is that an acid component collection liquid storage tank 7 is provided. The electrodialysis unit 4 and the acid component collection liquid storage tank 7 are connected by an acid component collection liquid discharge line L3 and an acid component collection liquid introduction line L5. The collection liquid circulates between the electrodialysis unit 4 and the acid component collection liquid storage tank 7, and in the electrodialysis unit 4, the acid components are transferred to the collection liquid, and the acid component concentration in the collection liquid increases. On the other hand, the acid component collection liquid storage tank 7, the amine separation unit 5, and the acid component separation unit 6 are connected by an unpurified acid component collection liquid discharge line 6, a connection line L4, and a purified acid component collection liquid introduction line, and a part of the collection liquid stored in the acid component collection liquid storage tank 7 circulates between them. The absorbent circulating through the electrodialysis unit 4 and the absorbent circulating through the amine separation unit 5 and the acid component separation unit 6 can be circulated at independent flow rates. This makes the embodiment easier to use than the first or second embodiment, which does not include the acid component absorbent storage tank 7. For example, in the acid component separation unit, when neutralized salts are formed and cooled to generate precipitates, the circulation of the absorbent can be stopped during cooling, and the accumulated absorbent can be cooled. In addition, while measuring the acid component concentration, amine compound concentration, etc., of the circulating absorbent, the flow rates of the absorbent circulating through the electrodialysis unit and the flow rates of the absorbent circulating through the amine separation unit 5 and the acid component separation unit 6 can be independently adjusted to optimize the purification of the absorption liquid.

[0040] (Fourth embodiment) 4 is a conceptual diagram of a CO2 gas removal apparatus according to a fourth embodiment. The main difference between this embodiment and the first embodiment is that the order of the amine separation unit 5 and the acid component collection liquid separation unit 6 is reversed. As in the second embodiment, this embodiment is preferably adopted in the case where the amine compounds can be efficiently removed when the concentration of the acid components is low in the method for separating amine compounds in the amine separation unit.

[0041] Fifth embodiment FIG. 5 is a conceptual diagram of a CO2 gas removal device according to the fifth embodiment. The main difference between this embodiment and the first embodiment is that an acid component collection liquid storage tank 7 is provided in series with the amine separation unit 5 and the acid component collection liquid separation unit 6. In this configuration, the flow rate of the circulating collection liquid can be adjusted by increasing or decreasing the amount of collection liquid stored in the acid component collection liquid storage tank. In this method, the range of flow rate adjustment of the collection liquid is narrowed, but the configuration of the device can be simplified compared to the third or fourth embodiment. In this embodiment, it is possible to directly send the liquid from the acid component collection liquid separation unit to the electrodialysis unit. In addition, since the collection liquid after the acid components are separated is supplied to the electrodialysis unit, it is expected that the efficiency of removing the acid components in the electrodialysis unit can be improved.

[0042] In the fifth embodiment, the order in which the amine separation unit 5, the acid component absorption liquid separation unit 6, and the acid component absorption liquid storage tank 7 are connected is not particularly limited, and they can be connected in any order.

[0043] Sixth embodiment FIG. 6 is a conceptual diagram of a CO2 gas removal device according to the sixth embodiment. This embodiment differs from the fifth embodiment in that the once purified trapping liquid is circulated to an acid component trapping liquid storage tank 7 by a purified acid component trapping liquid circulation line. With this configuration, a purified trapping liquid containing fewer acid components and amine compounds can be introduced into the electrodialysis unit, and the flow rate of the trapping liquid can be easily adjusted. Note that the flow rate of the trapping liquid can be more easily adjusted by providing a bypass for introducing the trapping liquid from the acid component trapping liquid storage tank 7 to the acid component trapping liquid introduction line L5 or the electrolysis unit 4.

[0044] Although the CO2 gas removal device and removal method according to several embodiments of the present invention have been described above, these embodiments are presented as examples and do not limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, substitutions, modifications, additions, etc. can be made without departing from the gist of the invention. These embodiments and their modifications are included in the scope and gist of the invention, and are included in the scope of the invention and its equivalents described in the claims. [Explanation of symbols]

[0045] 1: CO2 gas removal device 2: CO2 capture unit 3: CO2 absorption liquid purification unit 4: Electrodialysis unit 4a: Electrode chamber 4b: Desalination room 4c: Concentration chamber 4d: Membrane 5: Amine separation unit 6: Acid component separation unit 7: Acid component collection liquid storage tank L1: Absorbent introduction line L2: Absorbent discharge line L3: Acid component collection liquid discharge line L4: Connecting line L5: Acid component collection liquid introduction line L6: Unpurified acid component collection liquid discharge line L7: Purified acid component collection liquid introduction line L8: Refined acid component collection liquid circulation line

Claims

1. CO ２ The gas to be treated containing an amine compound is treated with ２ Contact with the absorption liquid ２ The gas is absorbed and CO ２ CO gas absorbed ２ CO from the absorption liquid ２ Gas is collected and CO ２ The absorbing liquid is regenerated and CO ２ CO reused as absorbent ２ A separation and recovery unit; The CO ２ The acid components are removed from the absorption liquid by electrodialysis to obtain the CO ２ CO to purify the absorption liquid ２ an absorption liquid purification unit; CO ２ 1. A gas removal apparatus comprising: CO ２ The absorption liquid purification unit The CO 2 exchange membrane is provided between a pair of opposing electrodes, a dilution compartment, a concentration compartment, and a membrane selected from a cation exchange membrane, an anion exchange membrane, and a bipolar membrane, which is disposed between the dilution compartment and the concentration compartment. ２ The acid component is dissolved from the absorption liquid into the acid component collection liquid introduced into the concentration chamber, ２ an electrodialysis unit for purifying the absorption liquid; an amine separation unit for separating an amine compound contained in the acid component collection liquid; an acid component separation unit for separating the acid components contained in the acid component collection liquid; The electrodialysis unit, the amine separation unit and the acid component separation unit are connected so that the acid component collection liquid can be circulated. ２ Gas removal device.

2. The CO 2 capture apparatus according to claim 1, further comprising an acid component capture liquid storage tank for temporarily storing the acid component capture liquid. ２ Gas removal device.

3. 3. The CO 2 purification method according to claim 1, wherein the acid component separation unit includes an alkaline compound introduction unit that introduces an alkaline compound containing an alkaline metal or an alkaline earth metal as a cation into the acid component collection liquid. ２ Gas removal device.

4. The CO 2 separation method according to claim 1 or 2, wherein the acid component separation unit further comprises a cooling unit for cooling the acid component collection liquid to which the alkaline compound has been added. ２ Gas removal device.

5. The CO 2 treatment method according to claim 3, further comprising an acid component recovery unit for separating and recovering the neutralized salt precipitated by cooling with the cooling unit. ２ Gas removal device.

6. 3. The CO2 extractor according to claim 1, wherein the amine separation unit separates the amine compounds from the acid component collection solution by reverse osmosis, forward osmosis, ultrafiltration, ion exchange resin, or electrodialysis. ２ Gas removal device.

7. a part of the acid component collection liquid is circulated from the acid component collection liquid storage tank to the acid component collection liquid storage tank via the electrodialysis unit; 3. The CO 2 purification method according to claim 2, wherein another part of the acid component collection liquid is circulated to the acid component collection liquid storage tank via the amine separation unit and the acid component separation unit. ２ Gas removal device.

8. The acid component collection liquid is circulated from the acid component collection liquid storage tank to the acid component collection liquid storage tank via the electrodialysis unit, the amine separation unit, and the acid component separation unit. The CO according to claim 2 ２ Gas removal device.

9. The present invention comprises a deionization compartment, a concentration compartment, and a membrane selected from a cation exchange membrane, an anion exchange membrane, and a bipolar membrane, which are disposed between a pair of opposing electrodes, and CO containing an acid component is introduced into the deionization compartment. ２ The acid component is dissolved from the absorption liquid into the acid component collection liquid introduced into the concentration chamber, ２ an electrodialysis unit for purifying the absorption liquid; an amine separation unit for separating amine compounds contained in the acid component collection liquid; an acid component separation unit for separating the acid components contained in the acid component collection liquid; The electrodialysis unit, the amine separation unit and the acid component separation unit are connected so that the acid component collection liquid can be circulated. ２ Absorbent purification unit.

10. CO ２ The gas to be treated containing an amine compound is treated with ２ Contact with the absorption liquid ２ The gas is absorbed and CO ２ Gas absorbed CO ２ CO from the absorption liquid ２ Gas is collected and CO ２ The absorbing liquid is regenerated and CO ２ CO reused as absorbent ２ A separation and recovery method comprising the steps of: The acid component is transferred to the acid component collection liquid by electrodialysis, and the CO ２ purifying the absorption liquid; Separating the amine-based compound contained in the acid component collection liquid; and Separating the acid components contained in the acid component collection liquid. CO ２ Gas removal methods.

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