Bipolar membrane electrolyzer anode-cathode series circulating CO2 capture solution conversion and regeneration system and method

Abstract

This invention discloses a bipolar membrane electrolyzer anode-cathode series circulating CO2 capture solution conversion and regeneration system and method, belonging to the field of carbon capture and resource utilization technology. The system constructs a closed-loop circuit: packed tower → cathode chamber → gas-liquid separator → anode chamber → packed tower, converting HCO3-rich liquid into a CO2-rich solution. ‑ The collecting solution is first sent into the cathode chamber, where H2 is generated by the hydrolysis of the bipolar membrane. + CO2 is released and converted into syngas via a composite hydrophilic silver catalyst; the collected solution after the reaction is directly sent to the anode chamber, utilizing the OH- ions migrating through the bipolar membrane. ‑ The in-situ alkalization regeneration of the capture liquid is completed, and the regenerated solution is directly returned to the packed tower for recycling. Compared with the traditional thermal regeneration process of capture liquid, this invention does not require high-temperature desorption, significantly reduces energy consumption by more than 40%, and avoids the problems of capture liquid volatilization and equipment corrosion. The system is compact and has a short process, making it suitable for distributed carbon capture and conversion in high-emission industries such as power plants and steel.

Description

Technical Field

[0001] This invention belongs to the field of carbon dioxide resource utilization, and particularly relates to a bipolar membrane electrolyzer anode-cathode series circulating CO2 capture liquid conversion and regeneration system and method, which is applicable to the treatment of flue gas or tail gas in high-emission industries such as power, steel, cement, and chemical industries. Background Technology

[0002] Under the current circumstances, carbon dioxide capture, utilization, and storage (CCUS) is an indispensable core supporting technology for high-energy-consuming and high-carbon-emission industries to achieve deep decarbonization and green and low-carbon transformation. It is also currently the only technological path that can absorb carbon emissions from fossil fuel processes on a large scale and ensure industrial energy security. However, existing CO2 capture and electrocatalytic reduction processes are generally operated separately: the high-concentration CO2 captured must undergo multiple processes such as desorption, compression, storage, and transportation before entering the electrolysis unit. The energy consumption of intermediate links in the entire chain accounts for more than 50%, making the cost of traditional electrocatalytic CO2 reduction far higher than the economic threshold acceptable to the industry.

[0003] Direct electrolysis of the capture solution for CO2 electroreduction is considered the most promising alternative to the electroreduction of gaseous CO2, as it eliminates the need for energy-intensive CO2 desorption and compression processes, theoretically reducing total system energy consumption by over 40%. However, this technology still faces two major bottlenecks: Firstly, during the absorption of CO2 to form bicarbonate, the pH of the alkaline capture solution drops rapidly, significantly reducing capture capacity and rate, resulting in a single capture efficiency of less than 30%. Secondly, alkalinity regeneration of the capture solution is another major challenge for the large-scale application of this technology. Traditional thermal regeneration methods still require heating at temperatures above 120°C, accounting for up to 30% of energy consumption, and the secondary carbon emissions generated during regeneration offset some of the carbon reduction benefits. Existing electrochemical regeneration methods generally suffer from low current efficiency, severe electrode corrosion, and long regeneration cycles, making continuous and stable operation difficult.

[0004] While bipolar membrane water dissociation technology can generate acids and bases in situ, providing a new approach for low-temperature regeneration of the capture solution, existing research has largely focused on optimizing the performance of a single electrolyzer. It has failed to achieve deep coupling between efficient CO2 capture, electrocatalytic conversion, and in-situ regeneration of the capture solution, thus hindering the formation of a closed-loop cycle of carbon and alkalinity, resulting in low overall system efficiency. Therefore, there is an urgent need to develop an integrated reaction device to simultaneously address these technical challenges and promote the large-scale industrial application of CCUS technology in the chemical industry. Summary of the Invention

[0005] To address the problems of high energy consumption for collector regeneration, disconnect between the collection and conversion processes, and intermittent system operation in existing electrochemical carbon capture and conversion technologies, this invention provides a bipolar membrane electrolyzer anode-cathode series circulating CO2 capture liquid conversion and regeneration system and method.

[0006] To achieve the above-mentioned objectives, the present invention provides the following technical solution:

[0007] A bipolar membrane electrolyzer anode-cathode series circulating CO2 capture liquid conversion and regeneration system includes a bipolar membrane electrolyzer, a packed tower, a gas-liquid separator, and a pipeline system.

[0008] The packed tower is a CO2 capture site under high pH conditions, used to absorb CO2-containing waste gas and generate HCO3-rich gas. - The collected liquid. Preferably, the packed tower is provided with a gas inlet, a liquid storage zone, a packing layer, a liquid distributor and a demister from bottom to top.

[0009] The bipolar membrane electrolyzer is used to convert HCO3-rich... - The collection solution comprises a cathode chamber, an anode chamber, and a bipolar membrane disposed between the cathode and anode chambers. Under reverse bias, the bipolar membrane dissociates water into H₂. + and OH - H + Migration to the cathode chamber, OH - It migrates towards the anode chamber. Preferably, the cation exchange layer of the bipolar membrane faces the cathode catalyst, and the anion exchange layer faces the anode catalyst.

[0010] The cathode chamber is equipped with a composite hydrophilic silver cathode catalyst. Preferably, the composite hydrophilic silver cathode catalyst comprises a hydrophilic gas diffusion layer and a catalyst layer, wherein the catalyst layer is prepared from a slurry composed of silver nanoparticles, a binder, and a polar solvent. Preferably, a polytetrafluoroethylene filter membrane with a thickness of 50–500 μm and a pore size of 1–10 μm is provided between the bipolar membrane and the cathode electrode to form a pH gradient between the cathode catalyst and the bipolar membrane, maintaining the acidic CO2 release zone at the membrane interface and the alkaline CO2 reduction zone on the surface of the cathode catalyst.

[0011] The anode chamber is equipped with an IrO2-Ti anode catalyst. Compared to the nickel foam electrode commonly used in alkaline systems, the IrO2-Ti electrode exhibits poorer alkaline oxygen evolution performance, thus reducing OH content at the anode. - The consumption of alkalinity is used to achieve a surplus of anode alkalinity.

[0012] The cathode chamber and anode chamber of the bipolar membrane electrolyzer are connected in series through the gas-liquid separator. The connecting pipeline connects the liquid outlet of the packed tower to the inlet of the cathode chamber, the outlet of the cathode chamber to the inlet of the gas-liquid separator, the liquid outlet of the gas-liquid separator to the inlet of the anode chamber, and the outlet of the anode chamber to the liquid inlet of the packed tower, forming a closed-loop circulation path in which the collected liquid first passes through the cathode chamber and then through the anode chamber.

[0013] Preferably, the collecting solution is a K₂CO₃-KHCO₃ mixed system, and the initial collecting solution is a 0.5–2 mol / L K₂CO₃ solution. Using this system can suppress the anolyte oxygen evolution reaction, improve the regeneration efficiency of the collecting solution, and avoid the volatilization, degradation, and corrosion problems of organic amine solvents.

[0014] This invention also provides a method for converting and regenerating CO2 trapping solution in a bipolar membrane electrolyzer with the cathode and anode connected in series, using the above-mentioned system and including the following steps:

[0015] (1) Start the bipolar membrane electrolyzer and apply a reverse electric field to cause water dissociation in the bipolar membrane, H + Migration to the cathode chamber, OH - Migrate towards the anode chamber;

[0016] (2) OH- enrichment in the anode chamber - With CO3 2- The high-pH regenerated electrolyte enters the packed tower through pipelines and comes into countercurrent contact with CO2-containing gas introduced from the gas inlet, absorbing CO2 and generating HCO3. - ;

[0017] (3) Rich in HCO3 after absorbing CO2 - The collected solution is returned to the cathode chamber of the bipolar membrane electrolyzer via pipeline, where the H2O generated by the bipolar membrane hydrolysis... + With HCO3 - CO2 is released through an interfacial reaction between the bipolar membrane and the cathode catalyst. The released CO2 undergoes an electrocatalytic reduction reaction on the surface of the cathode composite hydrophilic silver electrode to generate CO.

[0018] A polytetrafluoroethylene filter membrane is provided between the bipolar membrane and the cathode catalyst, forming a pH gradient between the cathode catalyst and the bipolar membrane, maintaining the acidic CO2 release zone at the membrane interface and the alkaline CO2 reduction zone on the surface of the cathode catalyst.

[0019] (4) The gas-liquid mixture after the cathode reaction is separated into syngas by a gas-liquid separator, and the remaining liquid phase trap directly enters the anode chamber, where an oxygen evolution reaction occurs on the surface of the IrO2-Ti electrode. At the same time, OH- ions migrate through the bipolar film. - The collection solution is regenerated by alkalization;

[0020] (5) During the reaction, the capture liquid continuously circulates along the packed tower → cathode chamber → gas-liquid separator → anode chamber → packed tower to realize the continuous integrated operation of CO2 capture and conversion.

[0021] Preferably, the number of membrane stacks in the electrolyzer, the current density, and the circulation rate of the collector solution are adjusted to meet different flue gas treatment requirements. The selection of current density is subject to a trade-off between the alkalinity generation rate and the product selectivity. The alkalinity generation rate increases with increasing current density, but the CO selectivity decreases with increasing current density.

[0022] The beneficial effects of this invention are:

[0023] The present invention has the following advantages and positive effects compared with the prior art:

[0024] First, this invention couples three independent steps: CO2 capture, electrocatalytic conversion, and capture solution regeneration, constructing a closed-loop circulation path: packed tower → cathode chamber → gas-liquid separator → anode chamber → packed tower. After CO2 reduction in the cathode chamber, the capture solution directly enters the anode chamber for alkalization regeneration. The regenerated high-pH capture solution is then directly returned to the packed tower to absorb CO2, achieving uninterrupted closed-loop operation throughout the entire process. This eliminates high-cost steps such as CO2 purification, compression, storage, and transportation, resulting in a compact system and a reduction in energy consumption of over 30%.

[0025] Secondly, electrochemical in-situ regeneration of the capture solution is achieved through a series-connected anode and cathode internal circulation, eliminating the need for the high temperatures of 120–140°C required for traditional thermal regeneration. This reduces regeneration energy consumption by more than 50% and produces no secondary carbon emissions. The OH- produced by the bipolar membrane water dissociation... - OH- ions migrate through the anion exchange layer to the anode, while OH- ions generated by the cathode reaction... - As the collecting solution is transported to the anode side, both components together increase the OH- content of the collecting solution in the anode chamber. - Concentration, to achieve efficient in-situ regeneration of the alkalinity of the trapping solution.

[0026] Third, the entire system adopts an integrated design, eliminating the need for additional large-scale units such as CO2 desorption, compression, and purification. It uses a single bipolar membrane electrolyzer, which allows for flexible adjustment of the number of membrane stacks, current density, and collector circulation flow rate, adapting to different flue gas treatment needs and making it particularly suitable for industrial scenarios with dispersed emission sources.

[0027] Fourth, using IrO2-Ti anodes instead of traditional foamed nickel anodes results in poorer alkaline oxygen evolution performance, which can reduce OH content at the anode. - The consumption of alkalinity was reduced. Experiments showed that the alkalinity generation rate of the IrO2-Ti electrode was increased by 58.18% compared to nickel foam.

[0028] Fifth, a polytetrafluoroethylene filter membrane is placed between the cathode catalyst and the bipolar membrane to create a pH gradient between the bipolar membrane and the cathode catalyst, maintain the acidic CO2 release zone at the membrane interface and the alkaline CO2 reduction zone on the cathode catalyst surface, thereby improving the efficiency of CO2 release and electrocatalytic reduction. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of an integrated reaction device for converting and regenerating CO2 capture liquid based on a bipolar membrane electrolyzer with anode and cathode in series circulation, provided by an embodiment of the present invention.

[0030] Figure 2 This is a theoretical schematic diagram of CO2 capture solution conversion and regeneration based on the series circulation of anode and cathode in a bipolar membrane electrolyzer, provided in an embodiment of the present invention.

[0031] Figure 3 This is a diagram showing the generation of anolyte alkalinity in the anode chamber under different anolyte catalysts, provided in an embodiment of the present invention.

[0032] Figure 4 This is a diagram showing the alkalinity and product generation under different currents based on the anode-cathode series circulation mode provided in this embodiment of the invention.

[0033] Figure 5 This is a diagram showing the test results of the regeneration of the capture solution based on the series circulation of the anode and cathode in a bipolar membrane electrolyzer, as provided in an embodiment of the present invention.

[0034] The meanings of the markings in the diagram are as follows:

[0035] 1-Gas-liquid separator, 2-Packed tower, 3-Cathode flow field plate, 4-Hydrophilic gas diffusion layer, 5-Catalyst layer, 6-PTFE filter membrane, 7-Bipolar membrane, 8-IrO2-Ti anode, 9-Anode flow field plate, 10-Packed tower liquid outlet, 11-Cathode inlet, 12-Gas-liquid separator inlet, 13-Gas-liquid separator outlet, 14-Anode inlet, 15-Anode outlet, 16-Packed tower liquid inlet, 17-Flue gas inlet, 18-Flue gas outlet, 19-Bipolar membrane anion exchange layer, 20-Bipolar membrane cation exchange layer. Detailed Implementation

[0036] The present invention will be further described below with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and should not be used to limit the scope of protection of the present invention.

[0037] To address the problems of high energy consumption, step separation, and difficulty in electrolyte regeneration in the existing carbon dioxide capture and conversion process, this invention provides an integrated reaction device for CO2 capture liquid conversion and regeneration based on the series circulation of anode and cathode in a bipolar membrane electrolyzer. The invention will be described in detail below with reference to the accompanying drawings.

[0038] Example 1: System Structure and Operating Principle

[0039] like Figure 1As shown in the figure, the embodiment of the present invention provides an integrated reaction device for the conversion and regeneration of CO2 capture liquid based on the series circulation of anode and cathode in a bipolar membrane electrolyzer. It mainly includes a gas-liquid separator 1, a packed tower 2, a cathode flow field plate 3, a hydrophilic gas diffusion layer 4, a catalyst layer 5, a polytetrafluoroethylene filter membrane 6, a bipolar membrane 7, an IrO2-Ti anode 8, an anode flow field plate 9, a packed tower liquid outlet 10, a cathode inlet 11, a gas-liquid separator inlet 12, a gas-liquid separator outlet 13, an anode inlet 14, an anode outlet 15, a packed tower liquid inlet 16, a flue gas inlet 17, and a flue gas outlet 18.

[0040] The bipolar membrane electrolyzer, serving as the site for the conversion and regeneration of the collected solution, includes a bipolar membrane 7, a cathode chamber, and an anode chamber. The bipolar membrane 7, located between the cathode and anode chambers, undergoes a water dissociation reaction under a reverse electric field, generating H₂. + and OH - H + Migrating towards the cathode chamber, reacting with HCO3 - The reaction releases CO2 and OH- - The CO2 migrates towards the anode chamber. A composite hydrophilic silver catalyst (composed of a hydrophilic gas diffusion layer 4 and a catalyst layer 5) is placed between the cathode flow field plate 3 and the bipolar membrane 7, serving as the electrode for the electrocatalytic CO2 reduction reaction, which can reduce the CO2 introduced into the cathode chamber to products such as CO. A polytetrafluoroethylene filter membrane 6 is placed between the composite hydrophilic silver catalyst and the bipolar membrane 7 to maintain the acidic CO2 release zone at the membrane interface and the alkaline CO2 reduction zone on the cathode catalyst surface. An IrO2-Ti anode 8 is placed between the anode flow field plate 9 and the bipolar membrane 7, serving as an auxiliary reaction electrode.

[0041] Packed tower 2 is a CO2 capture site under high pH (>12) conditions. From bottom to top, it includes a gas inlet, a liquid storage zone, a packing layer, a liquid distributor, and a demister. The flue gas inlet 17 is located at the bottom of the packed tower 2 and is used to introduce the CO2-containing gas to be treated. The flue gas outlet 18 is located at the top of the tower and is used to discharge the captured gas. The liquid inlet 16 is located at the top of the tower and is used to introduce the high-pH electrolyte flowing from the electrolysis unit. The liquid outlet 10 is located at the bottom of the tower and is used to discharge the HCO3-rich electrolyte after CO2 absorption. - The collecting liquid.

[0042] The cathode chamber and anode chamber of the bipolar membrane electrolyzer are connected in series via the gas-liquid separator 1. The liquid outlet 10 of the packed tower is connected to the cathode inlet 11 of the cathode chamber, the outlet of the cathode chamber is connected to the gas-liquid separator inlet 12, the gas-liquid separator outlet 13 is connected to the anode inlet 14, and the anode outlet 15 is connected to the liquid inlet 16 of the packed tower, forming a closed-loop circulation path in which the collected liquid first passes through the cathode chamber and then through the anode chamber.

[0043] During the reaction, the bipolar membrane electrolyzer regenerates the electrolyte and performs electrocatalytic reduction of CO2, while the packed tower achieves efficient CO2 absorption. The two are coupled through a circulation pipeline system, forming a closed-loop operation. CO2 reduction synergistically with bipolar membrane water dissociation enriches the electrolyte with OH-. - With CO3 2- This provides a highly active absorbent for subsequent CO2 capture; the captured liquid after absorbing CO2 is returned to the electrolyzer, providing the carbon source required for electrocatalytic reduction on the cathode side, and regenerating the absorbent under the action of the bipolar membrane, thus completing the integrated continuous operation of CO2 capture and conversion.

[0044] like Figure 2 As shown, the bipolar membrane 7 consists of a bipolar anion exchange layer 19 and a bipolar cation exchange layer 20, with a water dissociation catalyst layer at the interface between them. Under reverse bias, water molecules in the bipolar membrane 7 undergo catalytic dissociation to produce H₂. + and OH - H + Transported to the cathode with HCO3 - The protonation reaction releases CO2, directly providing a carbon source for the cathode without the need for external gaseous CO2. The CO2 generated in situ is reduced to CO on the cathode catalyst surface, producing the byproduct OH. - OH- produced by the hydrolysis of the bipolar membrane - They then migrate to the anode via the anion exchange layer; simultaneously, OH- generated by the cathode reaction... - As the collecting solution is transported to the anode side, both components together increase the OH- content of the collecting solution in the anode chamber. - The concentration is adjusted to achieve in-situ regeneration of the alkalinity of the capture solution. The regenerated capture solution can then recapture CO2, forming a cycle of CO2 capture-electrolytic catalytic conversion-capture solution regeneration, thus avoiding the energy-intensive CO2 desorption and capture solution regeneration steps of traditional processes.

[0045] Example 2: Comparison of alkalinity generation effects of different anode catalysts

[0046] like Figure 3 As shown, the choice of anode catalyst affects the improvement of anode chamber basicity. Compared to the commonly used nickel foam electrode in alkaline anode systems, the IrO2-Ti electrode, which has poorer oxygen evolution performance in alkaline environments, can reduce OH- at the anode. - The consumption of anodic alkalinity is reduced, thus achieving a surplus in anodic alkalinity. Experimental results show that the alkalinity generation rate of the IrO2-Ti electrode is increased by 58.18% compared to nickel foam.

[0047] Example 3: Basicity and Product Selectivity at Different Current Densities

[0048] like Figure 4As shown, the alkalinity generation level in a bipolar membrane electrolyzer is affected by the current density. The alkalinity generation rate increases with increasing current density, but simultaneously, the CO selectivity decreases with increasing current density. Therefore, in practical applications, the selection of current density is subject to a trade-off between the alkalinity generation rate and product selectivity, and requires optimization and control based on specific process requirements.

[0049] Example 4: System Dynamic Steady-State Operation Test

[0050] like Figure 5 As shown, the CO2 capture liquid conversion and regeneration technology involves two reciprocal processes: the CO2 capture reaction in the packed tower consumes CO3. 2- HCO3 is generated - This will lower the solution pH; the CO2 reduction reaction at the cathode of the bipolar membrane electrolyzer reacts with the hydrolysis of the bipolar membrane to generate OH-. - The remaining HCO3 can be - Reconstituted into CO3 2- And accumulate OH - This will increase the pH of the solution.

[0051] During the 10–15 h period, the pH of the collecting solution decreased, and the collecting performance of the collecting solution declined sharply. When the CO2 collection rate matched the dynamic rate of electrochemical alkalinity, the system reached a dynamic steady state, and the pH and FEco (Faraday efficiency) remained stable for a certain period of time. After 19 h of CO2 input was stopped, as the electrolysis reaction in the bipolar membrane electrolyzer continued, the OH- generated at the cathode and anode... - Gradually accumulate, HCO3 - Converted to CO3 2- The pH of the collected solution rises; FEco decreases synchronously as the collected CO2 is consumed.

[0052] The above experimental results show that the system described in this invention can achieve long-term continuous and stable operation when the CO2 capture rate and the electrochemical alkalinity generation rate are dynamically matched, proving the feasibility and superiority of this technical solution.

[0053] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A bipolar membrane electrolyzer anode-cathode series circulating CO2 capture solution conversion and regeneration system, characterized in that, include: Bipolar membrane electrolyzer, packed tower, gas-liquid separator and connecting pipelines; The packed tower is a CO2 capture site under high pH conditions, used to absorb CO2-containing waste gas and generate HCO3-rich gas. - The collecting fluid; The bipolar membrane electrolyzer is used to convert HCO3-rich... - The collection solution comprises a cathode chamber, an anode chamber, and a bipolar membrane disposed between the cathode and anode chambers. Under reverse bias, the bipolar membrane dissociates water into H₂. + and OH - H + Migration to the cathode chamber, OH - Migrate towards the anode chamber; The cathode chamber is equipped with a composite hydrophilic silver cathode catalyst, and the anode chamber is equipped with an IrO2-Ti anode catalyst. The cathode chamber and anode chamber of the bipolar membrane electrolyzer are connected in series through the gas-liquid separator. The connecting pipeline connects the liquid outlet of the packed tower to the inlet of the cathode chamber, the outlet of the cathode chamber to the inlet of the gas-liquid separator, the liquid outlet of the gas-liquid separator to the inlet of the anode chamber, and the outlet of the anode chamber to the liquid inlet of the packed tower, forming a closed-loop circulation path in which the collected liquid first passes through the cathode chamber and then through the anode chamber.

2. The bipolar membrane electrolyzer anode-cathode series circulating CO2 capture solution conversion and regeneration system according to claim 1, characterized in that, The cation exchange layer of the bipolar membrane faces the cathode catalyst, and the anion exchange layer faces the anode catalyst.

3. The bipolar membrane electrolyzer anode-cathode series circulating CO2 capture solution conversion and regeneration system according to claim 1, characterized in that, A polytetrafluoroethylene filter membrane with a thickness of 50–500 μm and a pore size of 1–10 μm is provided between the bipolar membrane and the cathode electrode.

4. The bipolar membrane electrolyzer anode-cathode series circulating CO2 capture solution conversion and regeneration system according to claim 1, characterized in that, The composite hydrophilic silver cathode catalyst includes a hydrophilic gas diffusion layer and a catalyst layer, wherein the catalyst layer is prepared from a slurry composed of silver nanoparticles, a binder, and a polar solvent.

5. The bipolar membrane electrolyzer anode-cathode series circulating CO2 capture solution conversion and regeneration system according to claim 1, characterized in that, The packed tower is provided with a gas inlet, a liquid storage area, a packing layer, a liquid distributor, and a demister from bottom to top.

6. The bipolar membrane electrolyzer anode-cathode series circulating CO2 capture solution conversion and regeneration system according to claim 1, characterized in that, The collecting solution is a K2CO3-KHCO3 mixed system, which inhibits the oxygen evolution reaction at the anode and improves the regeneration efficiency of the collecting solution.

7. The bipolar membrane electrolyzer anode-cathode series circulating CO2 capture solution conversion and regeneration system according to claim 6, characterized in that, The initial collecting solution is a 0.5–2 mol / L K2CO3 solution, which is used to absorb CO2 and generate KHCO3. KHCO3 releases CO2 to provide a carbon source for the CO2 conversion at the cathode.

8. A method for converting and regenerating CO2 capture solution in a bipolar membrane electrolyzer with anode and cathode connected in series, using the system described in any one of claims 1-7, characterized in that, Includes the following steps: (1) Start the bipolar membrane electrolyzer and apply a reverse electric field to cause water dissociation in the bipolar membrane, H + Migration to the cathode chamber, OH - Migrate towards the anode chamber; (2) OH- enrichment in the anode chamber - With CO3 2- The high-pH regenerated capture solution enters the packed tower through pipelines and comes into countercurrent contact with the CO2-containing gas introduced from the gas inlet, absorbing CO2 and generating HCO3. - ; (3) Rich in HCO3 after absorbing CO2 - The collected solution is returned to the cathode chamber of the bipolar membrane electrolyzer via pipeline, where the H2O generated by the bipolar membrane hydrolysis... + With HCO3 - CO2 is released through an interfacial reaction between the bipolar membrane and the cathode catalyst. The released CO2 undergoes an electrocatalytic reduction reaction on the surface of the cathode composite hydrophilic silver electrode to generate CO. (4) The gas-liquid mixture after the cathode reaction is separated into syngas by a gas-liquid separator, and the remaining liquid phase trap directly enters the anode chamber, where an oxygen evolution reaction occurs on the surface of the IrO2-Ti electrode. At the same time, OH- ions migrate through the bipolar film. - The collection solution is regenerated by alkalization; (5) During the reaction, the capture liquid continuously circulates along the packed tower → cathode chamber → gas-liquid separator → anode chamber → packed tower to realize the continuous integrated operation of CO2 capture and conversion.

9. The method for converting and regenerating CO2 capture solution in a bipolar membrane electrolyzer with connected anode and cathode according to claim 8, characterized in that, In step (3), a polytetrafluoroethylene filter membrane is provided between the bipolar membrane and the cathode catalyst to form a pH gradient between the cathode catalyst and the bipolar membrane, maintaining the acidic CO2 release zone at the membrane interface and the alkaline CO2 reduction zone on the surface of the cathode catalyst.

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