Methods for purifying thermally stable salts and recovering amines from decarbonized amine solutions

Abstract

This invention relates to the field of carbon dioxide capture technology and discloses a method for purifying thermally stable salts and recovering amines from decarbonized amine solution. The method includes the following steps: (1) filtering the decarbonized amine solution; (2) performing ion exchange with an anion exchange resin on the filtered amine solution and collecting the effluent; (3) regenerating the saturated anion exchange resin during the ion exchange process in step (2) using an alkaline solution and collecting the regenerated solution; (4) adding acid to the regenerated solution and adjusting the pH value to 6-6.5; then adding alkali and adjusting the pH value to 8.5-9.5; (5) subjecting the solution after pH adjustment in step (4) to electrodialysis. According to the technical solution of this invention, by filtering, ion exchange purification, chemical modulation, and electrodialysis of the decarbonized amine solution, efficient purification of the decarbonized amine solution and efficient recovery of amines can be achieved.

Description

Technical Field

[0001] This invention relates to the field of carbon dioxide capture technology, and more specifically to a method for purifying thermally stable salts and recovering amines from decarbonized amine solutions. Background Technology

[0002] Global warming is becoming an increasingly prominent issue, with massive emissions of greenhouse gases being one of the main causes. Industrial carbon emissions, primarily composed of carbon dioxide, have garnered increasing attention, prompting governments and businesses to explore large-scale capture, storage, and utilization of carbon dioxide. Among numerous capture methods, chemical absorption has become mainstream due to its high efficiency and relatively mature technology. Commonly used chemical absorbents include amine solutions such as methyldiethanolamine (MDEA), diethanolamine (DEA), and triethanolamine (TEA). These absorbents effectively capture and separate carbon dioxide through acid-base reactions, exhibiting high absorption capacity and low regeneration energy consumption.

[0003] In long-term carbon dioxide capture processes, the accumulation of heat-stable salts (HSS) in the commonly used absorbent amine solution is a prevalent problem. These HSSs primarily originate from impurities in carbon dioxide, such as sulfates, sulfides, and nitrates. These inorganic salts react with the amine to form recalcitrant salts, leading to a decrease in the thermal stability of the solution. Furthermore, high-temperature, high-pressure operating conditions and the recycling of the solution also accelerate HSS formation, thereby affecting the absorbent's decarbonization performance and the safety of the equipment.

[0004] Several methods have been developed for removing HSS from alkanolamine solutions, including ion exchange, membrane separation, electrodialysis, and vacuum distillation. Ion exchange purifies the solution by adsorbing HSS through resin; membrane separation uses semi-permeable membranes to filter out HSS; electrodialysis removes HSS by driving ion migration through an electric field; and vacuum distillation separates the components based on their boiling point differences.

[0005] Alkylamine solutions, as effective carbon dioxide absorbers, utilize an absorption mechanism involving the chemical reactions of primary, secondary, and tertiary amines with carbon dioxide. Primary and secondary amines first undergo an acid-base neutralization reaction with CO2 during carbon dioxide absorption, forming carbamates. Specifically, primary amines (such as MDEA) react with CO2 to form primary carbamates; secondary amines (such as DEA) form secondary carbamates. Tertiary amines (such as TEA), lacking reactive hydrogen atoms on their nitrogen atom, do not directly form carbamates with CO2, but instead form bicarbonate intermediates. The formation of these carbamates is reversible; under heating or reduced pressure, CO2 can be released, regenerating the amine.

[0006] During the long-term recycling of alkanolamine solutions, the accumulation of heat-stable salts (HSS) is inevitable. To maintain the absorption efficiency of the solution, these HSS need to be removed periodically. However, existing methods for HSS removal, such as ion exchange, membrane separation, and electrodialysis, often remove not only HSS but also carbamates from the solution. This is because carbamates and HSS share certain chemical similarities, making them difficult to completely separate during removal. This non-selective removal process leads to a significant loss of amine, thereby reducing the absorption capacity and economic efficiency of the alkanolamine solution.

[0007] In conclusion, developing methods that can effectively remove HSS and efficiently recover amines is of great significance for improving the recycling efficiency of amine solutions and reducing operating costs. Summary of the Invention

[0008] The purpose of this invention is to overcome the problem in existing technologies where the chemical structures of thermally stable salts and carbamates are similar, leading to the loss of amines due to the removal of carbamates along with the removal of thermally stable salts accumulated during the recycling of alkanolamine solutions. This invention provides a method for purifying thermally stable salts and recovering amines from decarbonized amine solutions. This method achieves efficient removal of thermally stable salts and recovery of amines from decarbonized amine solutions.

[0009] To achieve the above objectives, the present invention provides a method for purifying thermally stable salts and recovering amines from a decarbonized amine solution, the method comprising the following steps: (1) Filter the decarbonized amine solution; (2) The amine solution obtained after filtration is subjected to ion exchange with anion exchange resin, and the effluent is collected; (3) Use an alkaline solution to regenerate the saturated anion exchange resin in step (2) during the ion exchange process, and collect the regenerated solution; (4) Add acid to the regenerated solution and adjust the pH to 6-6.5; then add alkali and adjust the pH to 8.5-9.5; (5) The solution after pH adjustment in step (4) is subjected to electrodialysis.

[0010] Preferably, the decarbonized amine solution is an alcohol amine solution containing a thermally stable salt.

[0011] Preferably, in step (1), the filtration process is carried out in a bag filter or a pressure filter, and the pore size of the filter is 1-100 μm.

[0012] Preferably, in step (2), the ion exchange process includes: passing the filtered amine solution through the anion exchange resin bed in the ion exchange device, and the flow rate of the filtered amine solution is 0.1-10 L / min.

[0013] Preferably, the anion exchange resin is at least one of a strong basic ion exchange resin, a weak basic ion exchange resin, and a strong-weak basic mixed ion exchange resin.

[0014] Preferably, in step (3), the regeneration process includes: passing the alkaline solution through the anion exchange resin bed in the ion exchange device, wherein the flow rate of the alkaline solution is 5-20 mL / min, and the contact time between the alkaline solution and the saturated adsorbed anion exchange resin is 5-10 min.

[0015] Preferably, the alkaline solution is a sodium hydroxide solution and / or a potassium hydroxide solution.

[0016] Preferably, in step (4), the acid is at least one of sulfuric acid, hydrochloric acid and nitric acid.

[0017] Preferably, in step (4), the alkali is at least one of sodium hydroxide, potassium hydroxide and ammonia water.

[0018] Preferably, in step (5), the conditions for the electrodialysis treatment include: voltage of 15-20V, current of 0.1-0.8A, and flow rate of 10-20mL / min.

[0019] Preferably, the method further includes returning the effluent obtained in step (2) back to the carbon capture system for reuse.

[0020] According to the method for purifying thermally stable salts and recovering amines using decarbonized amine solution described in this invention, by filtering, ion exchange purification, chemical modulation and electrodialysis treatment of the decarbonized amine solution, the decarbonized amine solution can effectively remove thermally stable salts while also achieving efficient recovery of amines. Detailed Implementation

[0021] The following provides a detailed description of specific embodiments of the present invention. It should be understood that the specific embodiments described herein are for illustrative and explanatory purposes only and are not intended to limit the scope of the invention.

[0022] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0023] The method for purifying thermally stable salts and recovering amines from decarbonized amine solution according to the present invention includes the following steps: (1) Filter the decarbonized amine solution; (2) The amine solution obtained after filtration is subjected to ion exchange with anion exchange resin, and the effluent is collected; (3) Use an alkaline solution to regenerate the saturated anion exchange resin in step (2) during the ion exchange process, and collect the regenerated solution; (4) Add acid to the regenerated solution and adjust the pH to 6-6.5; then add alkali and adjust the pH to 8.5-9.5; (5) The solution after pH adjustment in step (4) is subjected to electrodialysis.

[0024] In the method described in this invention, the decarbonized amine solution can be an alkanolamine solution containing a heat-stable salt. The heat-stable salt can be at least one selected from hydrochloride, sulfate, formate, acetate, oxalate, thiocyanate, and thiosulfinate. The alkanolamine solution can include at least one selected from primary amine (MDEA), secondary amine (DEA), and tertiary amine (TEA). The product of the reaction between the alkanolamine solution and carbon dioxide can be a carbamate. Specifically, the reaction product of the primary amine (MDEA) and carbon dioxide is a primary carbamate, the reaction product of the secondary amine (DEA) and carbon dioxide is a secondary carbamate, and the reaction product of the tertiary amine and carbon dioxide is a bicarbonate intermediate. The reaction between the alkanolamine solution and carbon dioxide is reversible; under heating and / or reduced pressure, carbon dioxide gas can be released, achieving amine regeneration.

[0025] In step (1), the filtration process can be carried out in a bag filter or a pressure filter, and the pore size of the filter can be 1-100 μm. The bag filter can be at least one of a single-bag filter, a multi-bag filter, a rocker-arm bag filter, and a high-precision bag filter. The pressure filter can be at least one of a quartz sand filter, an activated carbon filter, and a manganese sand filter. In a more preferred embodiment, the filtration process can be carried out in a pressure filter. The filter medium of the filter can be at least one of stainless steel, activated carbon, fiber material, and glass fiber (PTFE). In the most preferred embodiment, the filter medium of the filter is made of stainless steel. The filter medium of the filter is replaced as needed when the filter is overloaded.

[0026] In step (2), the ion exchange process may include: passing the filtered amine solution through an anion exchange resin bed in an ion exchange device, wherein the flow rate of the filtered amine solution may be 0.1-10 L / min. More preferably, the flow rate of the filtered amine solution is 1-8 L / min. The ion exchange process can be carried out in various conventional ion exchange devices in the art.

[0027] In step (2), the anion exchange resin can be at least one of a strong basic ion exchange resin, a weak basic ion exchange resin, and a strong-weak basic mixed ion exchange resin. In the most preferred embodiment, the anion exchange resin is a weak basic anion exchange resin, such as the weak basic anion exchange resin with product model D301 purchased from Langfang Aoguang Energy Saving Technology Co., Ltd.

[0028] In step (3), the regeneration process may include: passing the alkaline solution through the anion exchange resin bed in the ion exchange device, wherein the flow rate of the alkaline solution may be 5-20 mL / min, and the contact time between the alkaline solution and the saturated anion exchange resin may be 5-10 min. More preferably, the flow rate of the alkaline solution is 8-18 mL / min, and the contact time between the alkaline solution and the saturated anion exchange resin is 6-8 min.

[0029] In the method described in this invention, the alkaline solution can be a sodium hydroxide solution and / or a potassium hydroxide solution. In the most preferred embodiment, the alkaline solution is a sodium hydroxide solution. The concentration of the alkaline solution can be 2-6 wt%, preferably 3-5 wt%, specifically, for example, 3 wt%, 3.2 wt%, 3.5 wt%, 3.7 wt%, 4 wt%, 4.2 wt%, 4.5 wt%, 4.7 wt%, or 5 wt%.

[0030] In step (4), acid is added to the regenerated solution, and the pH value is adjusted to 6-6.5. More preferably, acid is added to the regenerated solution, and the pH value is adjusted to 6.2-6.4. When the pH value of the regenerated solution is adjusted to the above-mentioned preferred range, NH4 can be... + By forming and maintaining the ionic form of thermally stable salts, better amine recovery can be achieved.

[0031] In step (4), an alkali is added to the regenerated solution, and the pH value is adjusted to 8.5-9.5. More preferably, an alkali is added to the regenerated solution, and the pH value is adjusted to 8.8-9.3. When the pH value of the regenerated solution is adjusted to the above-mentioned preferred range, the carbamate can be converted into a neutral form, resulting in better amine recovery.

[0032] In step (4), the acid may be at least one of sulfuric acid, hydrochloric acid, and nitric acid. In the most preferred embodiment, the acid is hydrochloric acid. The acid is used in the form of an aqueous solution. The concentration of the acid may be 0.5-5 wt%, preferably 0.5-2 wt%, specifically, for example, 0.5 wt%, 0.8 wt%, 1.2 wt%, 1.5 wt%, or 2 wt%.

[0033] In step (4), the alkali can be at least one of sodium hydroxide, potassium hydroxide, and ammonia. In the most preferred embodiment, the alkali is sodium hydroxide. The alkali is used in the form of an aqueous solution. The concentration of the alkali can be 0.5-5 wt%, preferably 1-3 wt%, specifically, for example, 1 wt%, 1.2 wt%, 1.5 wt%, 1.8 wt%, 2 wt%, 2.2 wt%, 2.5 wt%, 2.8 wt%, or 3 wt%.

[0034] In step (5), the conditions for the electrodialysis treatment may include: a voltage of 15-20V, a current of 0.1-0.8A, and a flow rate of 10-20mL / min. More preferably, the conditions for the electrodialysis treatment include: a voltage of 16-18V, a current of 0.2-0.6A, and a flow rate of 12-18mL / min. The electrodialysis treatment process can be carried out in various conventional electrodialysis devices in the art. According to this preferred embodiment, better purification of thermally stable salts and recovery of amines can be achieved.

[0035] In this invention, the method further includes returning the effluent obtained in step (2) to the carbon capture system for reuse. The carbon capture system includes a flue gas pretreatment system, an absorption system, a regeneration system, a compression drying system, and a refrigeration liquefaction system. The carbon capture system is used to absorb carbon dioxide gas from industrial waste gases.

[0036] The following examples further illustrate the method for purifying thermally stable salts and recovering amines from decarbonized amine solutions according to the present invention. These examples are implemented based on the technical solution of the present invention, providing detailed implementation methods and specific operating procedures; however, the scope of protection of the present invention is not limited to the following examples.

[0037] Unless otherwise specified, the experimental methods used in the following embodiments are conventional methods in the art. Unless otherwise specified, the experimental materials used in the following embodiments are commercially available.

[0038] In the following examples and comparative examples, the concentrations of thermally stable salts and amines in the samples were tested in the following manner.

[0039] Thermal stability salt concentration test: Take 50 mL of sample and heat it under reflux for 5 min to remove residual CO2 and H2S. After heating, cover the sample with a quartz glass lid and cool it in the dark. Use deionized water to compensate for the difference to ensure that the final sample volume is consistent with the initial volume. Weigh 2-3 g of sample into a 100 mL plastic cup and record the sample weight as . W Pour the sample into the resin column and rinse the plastic cup several times with deionized water. Pour the washings into the resin column as well, and then rinse with deionized water. Collect the effluent from the resin column in a 250 mL beaker. Test the effluent from the resin column with pH paper until it is neutral (pH=7) or equal to the pH of the washing water. Add 2-3 drops of 5 g / L phenolphthalein indicator to the beaker and titrate with 0.1 mol / L sodium hydroxide solution until it turns pink. Record the amount of sodium hydroxide solution consumed (V). The formula for calculating the thermally stable salt mass concentration Wt% is as follows: Wt%=

[0040] Amine concentration test: The amine concentration of the sample was tested using GC-MS. The chromatograph was preheated for 30 min, and 20 μL of sample was diluted in 50 g of deionized water. After injection, the amine concentration of the sample was determined by baseline correction, peak identification, and quantitative analysis of the chromatogram.

[0041] Example 1 (1) A solution of amine containing a high concentration of thermally stable salts that has been running for a long time in a certain field project was used as the initial sample. The sample was pumped into a filter device for filtration. The filter had a pore size of 50 μm.

[0042] (2) The amine solution obtained after filtration is pumped into an ion exchange device containing a weakly basic anion exchange resin (purchased from Langfang Aoguang Energy Saving Technology Co., Ltd., product model D301) for ion exchange. The flow rate of the amine solution is controlled at 5L / min to obtain the effluent A1 after ion exchange purification.

[0043] (3) Pump a 4 wt% sodium hydroxide solution into the ion exchange device to regenerate the anion exchange resin that is saturated during the ion exchange process. Control the flow rate of the sodium hydroxide solution to 15 mL / min and the contact time to 7 min. Collect the regenerated solution.

[0044] (4) Add the regenerated solution obtained in step (3) to a hydrochloric acid solution with a concentration of 1.5 wt%. Stir continuously during the addition process and use a pH meter to detect the pH value until the solution is 6.4. Then add a sodium hydroxide solution with a concentration of 1.8 wt% to the regenerated solution. Stir continuously during the addition process and use a pH meter to detect the pH value until the solution is 9.1, thus obtaining a solution with adjusted pH value.

[0045] (5) Pump the pH-adjusted solution obtained in step (4) into the electrodialysis device, control the voltage of the electrodialysis device to be 18V, the current to be 0.5A, the flow rate of the solution to be 15mL / min, and collect the effluent B1.

[0046] The initial sample, collected effluent A1, and effluent B1 were subjected to thermal stability salt concentration tests and amine concentration tests, respectively. The test results are as follows: The initial sample contained 2.95 wt% of thermally stable salts and 30.2 wt% of amines. The concentration of thermally stable salts in effluent A1 was 1.32 wt%, and the concentration of amines was 25.3 wt%. The concentration of thermally stable salts in effluent B1 is 0.65 wt%, and the concentration of amine is 4.2 wt%.

[0047] Example 2 (1) A solution of amine containing a high concentration of thermally stable salts that has been running for a long time in a certain field project was used as the initial sample. The sample was pumped into a filter device for filtration. The filter had a pore size of 50 μm.

[0048] (2) The amine solution obtained after filtration is pumped into an ion exchange device containing a weakly basic anion exchange resin (purchased from Langfang Aoguang Energy Saving Technology Co., Ltd., product model D301) for ion exchange. The flow rate of the amine solution is controlled at 8L / min to obtain the effluent A2 after ion exchange purification.

[0049] (3) Pump a 5 wt% sodium hydroxide solution into the ion exchange device to regenerate the anion exchange resin that is saturated during the ion exchange process. Control the flow rate of the sodium hydroxide solution to 18 mL / min and the contact time to 6 min, and collect the regenerated solution.

[0050] (4) Add the regenerated solution obtained in step (3) to a 5 wt% hydrochloric acid solution, stirring continuously during the addition process and using a pH meter to detect the pH value until the solution is 6.3; then add a 1.8 wt% sodium hydroxide solution to the regenerated solution, stirring continuously during the addition process and using a pH meter to detect the pH value until the solution is 9.0, thus obtaining a solution with adjusted pH value.

[0051] (5) Pump the pH-adjusted solution obtained in step (4) into the electrodialysis device, control the voltage of the electrodialysis device to be 17V, the current to be 0.6A, the flow rate of the solution to be 18mL / min, and collect the effluent B2.

[0052] The initial sample, collected effluent A2, and effluent B2 were subjected to thermal stability salt concentration tests and amine concentration tests, respectively. The test results are as follows: The initial sample contained 2.95 wt% of thermally stable salts and 30.2 wt% of amines. The concentration of thermally stable salts in effluent A2 was 1.25 wt%, and the concentration of amines was 24.6 wt%. The concentration of thermally stable salts in effluent B2 was 0.64 wt%, and the concentration of amines was 4.3 wt%.

[0053] Example 3 (1) A solution of amine containing a high concentration of thermally stable salts that has been running for a long time in a certain field project was used as the initial sample. The sample was pumped into a filter device for filtration. The filter had a pore size of 50 μm.

[0054] (2) The amine solution obtained after filtration is pumped into an ion exchange device containing a weakly basic anion exchange resin (purchased from Langfang Aoguang Energy Saving Technology Co., Ltd., product model D301) for ion exchange. The flow rate of the amine solution is controlled at 5L / min to obtain the effluent A3 after ion exchange purification.

[0055] (3) Pump a 4 wt% sodium hydroxide solution into the ion exchange device to regenerate the anion exchange resin that is saturated during the ion exchange process. Control the flow rate of the sodium hydroxide solution to 15 mL / min and the contact time to 7 min. Collect the regenerated solution.

[0056] (4) Add the regenerated solution obtained in step (3) to a 2 wt% hydrochloric acid solution, stirring continuously during the addition process and using a pH meter to detect the pH value until the solution is 6.2; then add a 3 wt% sodium hydroxide solution to the regenerated solution, stirring continuously during the addition process and using a pH meter to detect the pH value until the solution is 9.2, thus obtaining a solution with adjusted pH value.

[0057] (5) Pump the pH-adjusted solution obtained in step (4) into the electrodialysis device, control the voltage of the electrodialysis device to be 16V, the current to be 0.2A, the flow rate of the solution to be 12mL / min, and collect the effluent B3.

[0058] The initial sample, collected effluent A3, and effluent B3 were subjected to thermal stability salt concentration tests and amine concentration tests, respectively. The test results are as follows: The initial sample contained 2.95 wt% of thermally stable salts and 30.2 wt% of amines. The concentration of thermally stable salts in effluent A3 was 1.27 wt%, and the concentration of amines was 24.7 wt%. The concentration of thermally stable salts in effluent B3 was 0.61 wt%, and the concentration of amines was 4.2 wt%.

[0059] Example 4 The method of Example 1 was used to purify the thermally stable salts and recover the amines from an alcohol amine solution containing a high concentration of thermally stable salts that had been running for a long time in a certain field project. The difference was that in step (5), the voltage of the electrodialysis device was adjusted to 15V, the current was adjusted to 0.1A, and the flow rate was adjusted to 10mL / min, and finally, collection liquid A4 and collection liquid B4 were obtained.

[0060] The initial sample, collected effluent A4, and effluent B4 were subjected to thermal stability salt concentration tests and amine concentration tests, respectively. The test results are as follows: The initial sample contained 2.95 wt% of thermally stable salts and 30.2 wt% of amines. The concentration of thermally stable salts in effluent A4 was 1.32 wt%, and the concentration of amines was 25.3 wt%. The concentration of thermally stable salts in effluent B4 was 0.69 wt%, and the concentration of amines was 3.6 wt%.

[0061] Comparative Example 1 The method of Example 1 was used to treat the amine solution containing high concentrations of thermally stable salts in the long-term operation of the on-site engineering demonstration. The difference was that the electrodialysis process in step (5) was not carried out. Instead, the solution after pH adjustment in step (4) was directly used as effluent D1. The initial sample and the collected effluent D1 were tested for thermally stable salt concentration and amine concentration. The test results are as follows: The initial sample contained 2.95 wt% of thermally stable salts and 30.2 wt% of amines. The concentration of thermally stable salts in effluent D1 was 0.92 wt%, and the concentration of amines was 2.2 wt%.

[0062] A comparison of the data from Examples 1-4 and Comparative Example 1 shows that the method for purifying thermally stable salts and recovering amines using the decarbonized amine solution described in this invention can effectively remove thermally stable salts while also achieving efficient amine recovery.

[0063] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A method for purifying thermally stable salts and recovering amines from decarbonized amine solution, characterized in that, The method includes the following steps: (1) Filter the decarbonized amine solution; (2) The amine solution obtained after filtration is subjected to ion exchange with anion exchange resin, and the effluent is collected; (3) Use an alkaline solution to regenerate the saturated anion exchange resin in step (2) during the ion exchange process, and collect the regenerated solution; (4) Add acid to the regenerated solution and adjust the pH to 6-6.5; then add alkali and adjust the pH to 8.5-9.5; (5) The solution after pH adjustment in step (4) is subjected to electrodialysis; In step (4), the acid is hydrochloric acid; the base is sodium hydroxide; In step (5), the conditions for the electrodialysis treatment include: voltage of 15-20V, current of 0.1-0.8A, and flow rate of 10-20mL / min.

2. The method according to claim 1, characterized in that, The decarbonized amine solution is an alcohol amine solution containing a thermally stable salt.

3. The method according to claim 1, characterized in that, In step (1), the filtration process is carried out in a bag filter or a pressure filter, and the pore size of the filter is 1-100 μm.

4. The method according to claim 1, characterized in that, In step (2), the ion exchange process includes: passing the filtered amine solution through the anion exchange resin bed in the ion exchange device, and the flow rate of the filtered amine solution is 0.1-10 L / min.

5. The method according to claim 1 or 4, characterized in that, The anion exchange resin is at least one of a strong basic ion exchange resin, a weak basic ion exchange resin, and a mixed strong-weak basic ion exchange resin.

6. The method according to claim 1, characterized in that, In step (3), the regeneration process includes: passing the alkaline solution through the anion exchange resin bed in the ion exchange device, wherein the flow rate of the alkaline solution is 5-20 mL / min, and the contact time between the alkaline solution and the saturated adsorbed anion exchange resin is 5-10 min.

7. The method according to claim 1 or 6, characterized in that, The alkaline solution is a sodium hydroxide solution and / or a potassium hydroxide solution.

8. The method according to claim 1, characterized in that, The method also includes returning the effluent obtained in step (2) back to the carbon capture system for reuse.