Systems and methods for oxygen reduction assisted electrochemical carbon capture desorption

Abstract

The application discloses a system and method for oxygen-reduction-assisted electrochemical carbon capture desorption. The system comprises an adsorption unit, an amine-rich liquid conveying unit, an electrochemical desorption unit, a gas and power supply unit and a gas-liquid separation unit. The adsorption unit is used for adsorbing carbon dioxide in flue gas to obtain clean flue gas and amine-rich liquid. The amine-rich liquid conveying unit is used for stably conveying the amine-rich liquid to the electrochemical desorption unit. The electrochemical desorption unit is used for desorbing carbon dioxide in the amine-rich liquid to realize amine liquid regeneration. The gas and power supply unit is used for providing high-humidity oxygen and stable voltage for the electrochemical desorption unit. The gas-liquid separation unit is used for deeply separating and purifying the carbon dioxide crude product desorbed by the electrochemical desorption unit to obtain high-purity carbon dioxide. The application can realize continuous adsorption of carbon dioxide in flue gas, has low desorption energy consumption, and can also realize cyclic regeneration of the solvent.

Description

Technical Field

[0001] This invention belongs to the field of carbon capture technology. Specifically, this invention relates to a system and method for oxygen reduction-assisted electrochemical carbon capture and desorption. Background Technology

[0002] Traditional thermal regeneration carbon capture accounts for 60%-80% of the total energy consumption of the system (steam temperature >100℃). Although electrochemical methods can achieve desorption at room temperature, the high overpotential of the oxygen evolution reaction (OER) at the anolyte (>1.23V) results in persistently high energy consumption for electrolysis. Furthermore, the sudden increase in local pH of the amine solution during desorption can easily trigger solvent degradation (such as the oxidation of MEA to form carboxylic acids).

[0003] In view of this, the present invention is hereby proposed. Summary of the Invention

[0004] This invention aims to at least partially address one of the technical problems in related technologies. To this end, embodiments of this invention propose a system and method for oxygen reduction-assisted electrochemical carbon capture and desorption.

[0005] To achieve the above-mentioned objectives, the present invention adopts the following technical solution:

[0006] In a first aspect, embodiments of the present invention provide a system for oxygen reduction-assisted electrochemical carbon capture and desorption, the system comprising an adsorption unit, an amine-rich liquid delivery unit, an electrochemical desorption unit, a gas and power supply unit, and a gas-liquid separation unit; The adsorption unit includes a packed absorption tower, which is used to capture carbon dioxide from flue gas using an amine solution. The rich amine liquid conveying unit includes a rich amine liquid storage tank. The inlet of the rich amine liquid storage tank is connected to the rich amine liquid outlet of the packed absorption tower, and the outlet of the rich amine liquid storage tank is connected to the rich amine liquid inlet of the cathode chamber of the electrochemical desorption unit, for conveying the rich amine liquid formed in the adsorption unit to the cathode chamber of the electrochemical desorption unit. The electrochemical desorption unit includes an electrolytic cell, which includes a cathode chamber and an anode chamber. The cathode chamber and the anode chamber are separated by a separation membrane. The cathode chamber is equipped with a cathode electrode for performing an oxygen reduction reaction to desorb carbon dioxide from the amine-rich solution. The anode chamber is equipped with an anode electrode for performing a water oxidation reaction to maintain the charge balance of the system. The gas supply and power supply unit includes a gas supply component and a power supply component. The gas supply component includes an oxygen supply device and a humidifier, which are used to continuously supply high-humidity oxygen to the cathode chamber of the electrochemical desorption unit. The power supply component includes a DC power supply and electrode connection terminals, which are used to provide a stable voltage to the electrochemical desorption unit. The gas-liquid separation unit includes a gas-liquid separator and a demisting component. The demisting component is disposed inside the gas-liquid separator. The inlet of the gas-liquid separator is connected to the top gas outlet of the cathode chamber of the electrochemical desorption unit and to the bottom amine-deficient liquid outlet of the cathode chamber of the electrochemical desorption unit. The amine-deficient liquid outlet of the gas-liquid separator is connected to the amine-deficient liquid inlet of the adsorption unit.

[0007] This invention utilizes the oxygen reduction reaction (ORR) to replace the traditional anodic reaction, achieving: in-situ heat generation in the cathode region (enthalpy change ΔH < 0), and a localized alkaline environment (ORR generates OH-). - This invention accelerates carbon dioxide desorption, reduces theoretical voltage requirements, and lowers energy consumption. Furthermore, the system in this embodiment eliminates the need for an external heater, which reduces the size of the equipment.

[0008] In some embodiments, the packed absorption tower includes a gas distributor, a packing layer, and a liquid distributor arranged sequentially from bottom to top, wherein the packing layer is filled with an amine solution.

[0009] In some embodiments, the rich amine liquid delivery unit further includes a corrosion-resistant circulating pump and a flow regulating valve, wherein the corrosion-resistant circulating pump and the flow regulating valve are respectively disposed on the connecting pipeline between the outlet of the rich amine liquid storage tank and the inlet of the rich amine liquid in the cathode chamber of the electrolytic cell.

[0010] In some embodiments, the cathode electrode is a porous conductive substrate supported on an oxygen reduction catalyst, and the surface of the cathode electrode is provided with serpentine oxygen channels or grid-like oxygen channels. And / or, the anode electrode is an IrO2 / Ti electrode; And / or, the separation membrane is an anion exchange membrane.

[0011] In some embodiments, the gas supply assembly further includes a gas flow controller, which is disposed on the connecting pipeline between the oxygen supply device and the cathode chamber of the electrolytic cell.

[0012] In some embodiments, the system further includes an expansion valve disposed on the connecting pipe between the top outlet of the cathode chamber of the electrolytic cell and the inlet of the gas-liquid separator.

[0013] In some embodiments, the defogging assembly includes at least two defogging devices arranged vertically at intervals.

[0014] Furthermore, the demister is made of polytetrafluoroethylene.

[0015] Secondly, embodiments of the present invention also propose a method for oxygen reduction-assisted electrochemical carbon capture and desorption, implemented using the system described in the first aspect, comprising the following steps: (1) The flue gas is introduced into the packed absorption tower of the absorption unit and comes into countercurrent contact with the ammonium solution to achieve the absorption of carbon dioxide and form a rich amine liquid; (2) The rich amine solution is transported to the cathode chamber of the electrochemical desorption unit and an oxygen reduction reaction is carried out under the action of an applied voltage to obtain a first lean amine solution and a gas-liquid mixture composed of carbon dioxide and amine liquid mist. (3) The first lean amine solution and the gas-liquid mixture are transported together to the gas-liquid separation unit for gas-liquid separation to obtain high-purity carbon dioxide and the second lean amine solution, and the second lean amine solution is recycled back to the absorption unit.

[0016] In some embodiments, in step (2), the oxygen reduction reaction is carried out at an applied voltage of 0.6V and a current density of 80mA / cm². 2 The oxygen reduction reaction was carried out under the following conditions, and the reaction temperature was 65±2℃. And / or, in step (3), the purity of the high-purity carbon dioxide is >99.2%.

[0017] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the structure of the oxygen reduction-assisted electrochemical carbon capture and desorption system according to an embodiment of the present invention.

[0019] Reference numerals: 1-packed absorption tower, 101-gas distributor, 102-packing layer, 103-liquid distributor, 2-rich amine liquid storage tank, 3-corrosion resistant circulating pump, 4-flow regulating valve, 5-electrolytic cell, 501-cathode chamber, 502-anode chamber, 503-separation membrane, 5011-cathode electrode, 5021-anode electrode, 6-gas supply assembly, 601-oxygen supply device, 602-humidifier, 7-power supply assembly, 701-DC power supply, 702-electrode connection terminal, 8-expansion valve, 9-gas-liquid separator, 901-first demister, 902-second demister. Detailed Implementation

[0020] The embodiments of the present invention are described in detail below. These embodiments are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0021] In this invention, when a value is described as a range, it should be understood that such disclosure includes disclosure of all possible subranges within that range, as well as specific numerical values ​​falling within that range, regardless of whether specific numerical values ​​or specific subranges are explicitly specified.

[0022] In this invention, the terms “comprising” and “including” and their various variations mean that other elements or wholes may be included but are not specifically described.

[0023] In this invention, the term "and / or" is merely a description of the relationship between related objects, indicating that there can be three relationships. For example, A and / or B can represent three situations: A exists alone, A and B exist simultaneously, and B exists alone.

[0024] Firstly, such as Figure 1 As shown in the figure, an embodiment of the present invention proposes an oxygen reduction-assisted electrochemical carbon capture and desorption system, including an adsorption unit, an amine-rich liquid delivery unit, an electrochemical desorption unit, a gas and power supply unit, and a gas-liquid separation unit.

[0025] The adsorption unit includes a packed absorber tower 1, whose main function is to capture carbon dioxide from flue gas using an amine solution. As the flue gas passes through the packed absorber tower 1, the carbon dioxide is absorbed by the ammonium solution, forming a carbon dioxide-rich amine solution.

[0026] The rich amine solution delivery unit includes a rich amine solution storage tank 2. The inlet of the rich amine solution storage tank 2 is connected to the rich amine solution outlet of the packed absorption tower 1, and the outlet of the rich amine solution storage tank 2 is connected to the rich amine solution inlet of the cathode chamber 501 of the electrochemical desorption unit. In this way, the rich amine solution formed in the adsorption unit can be stably delivered to the cathode chamber 501 of the electrochemical desorption unit.

[0027] The electrochemical desorption unit includes an electrolytic cell 5, which comprises a cathode chamber 501 and an anode chamber 502. The cathode chamber 501 and anode chamber 502 are separated by a separation membrane 503. The cathode chamber 501 contains a cathode electrode 5011 for an oxygen reduction reaction to desorb carbon dioxide from the amine-rich solution. The anode chamber 502 contains an anode electrode 5021 for a water oxidation reaction to maintain the system's charge balance. In this unit, carbon dioxide is desorbed from the amine-rich solution, thus regenerating the amine solution.

[0028] It should be noted that during the carbon dioxide desorption process, for the alkaline organic amine component of the amine liquid, the ORR→ local pH is high and there are trace amounts of oxidizing intermediates. Therefore, the carbon dioxide desorption process may entrain amine liquid droplets, amine mist, and liquid droplets. That is, the obtained carbon dioxide gas will contain amine liquid mist, and the two form a gas-liquid mixture, which is discharged through the gas outlet at the top of the cathode chamber and transported to the gas-liquid separation unit for further separation and purification to improve the purity of the carbon dioxide product.

[0029] The gas supply and power supply unit includes a gas supply component 6 and a power supply component 7. The gas supply component 6 includes an oxygen supply device 601 and a humidifier 601, which are used to continuously supply high-humidity oxygen to the cathode chamber 501 of the electrochemical desorption unit. The power supply component 7 includes a DC power supply 701 and an electrode connection terminal 702, which are used to provide a stable voltage to the electrochemical desorption unit.

[0030] The gas-liquid separation unit includes a gas-liquid separator 9 and a demister assembly. The demister assembly is located inside the gas-liquid separator (more specifically, along the gas flow path of the gas-liquid separator 9). The inlet of the gas-liquid separator 9 is connected to the top outlet of the cathode chamber 501 of the electrochemical desorption unit, and simultaneously to the bottom outlet of the lean amine liquid in the cathode chamber 501 of the electrochemical desorption unit. This allows the lean amine liquid generated by the electrochemical desorption unit, along with the gas-liquid mixture composed of carbon dioxide and amine mist, to be transported to the gas-liquid separator for further separation and purification. The lean amine liquid outlet of the gas-liquid separator 9 is connected to the lean amine liquid inlet of the adsorption unit. The gas-liquid separation unit performs deep gas-liquid separation and demister purification on the gas-liquid mixture stream formed in the electrochemical desorption unit. The demister assembly removes amine droplets and liquid mist entrained in the carbon dioxide gas, ensuring the purity of the resulting carbon dioxide product and reducing amine loss. It also reduces the risk of amine contamination to the equipment during subsequent compression, transportation, or utilization. After processing by this gas-liquid separation unit, high-purity carbon dioxide product gas with a purity >99.2% can be obtained. At the same time, lean amine liquid can also be separated and discharged through the lean amine liquid outlet at the bottom of the gas-liquid separator 9 and returned to the adsorption unit for recycling.

[0031] In some embodiments, the packed absorber 1 includes a gas distributor 101, a packing layer 102, and a liquid distributor 103 arranged sequentially from bottom to top. The packing layer 102 is filled with an amine solution (e.g., BEAAMP). The packed absorber 1 has a flue gas inlet at the bottom of one side and a clean flue gas outlet at the top (not shown in the figure). Meanwhile, the packed absorber 1 has a lean amine liquid inlet at the top of the other side and a rich amine liquid outlet at the bottom (not shown in the figure). Flue gas enters the packed absorber 1 from the bottom inlet and is evenly distributed by the gas distributor 101 before passing through the packing layer 102 from bottom to top. At the same time, amine solution enters the packed absorber 1 from the lean amine inlet at the top and is evenly sprayed by the liquid distributor 103, coming into countercurrent contact with the flue gas to absorb carbon dioxide in the flue gas, thus obtaining clean flue gas and rich amine solution (CO2 loading reaches 0.4-0.5 mol / mol amine). The clean flue gas is discharged through the clean flue gas outlet at the top of the packed absorber 1, and the rich amine solution is transported to the rich amine solution storage tank 2 through the rich amine solution outlet at the bottom of the packed absorber 1.

[0032] In some embodiments, the rich amine liquid conveying unit further includes a corrosion-resistant circulating pump 3 and a flow regulating valve 4, which are respectively installed on the connecting pipeline between the outlet of the rich amine liquid storage tank 2 and the inlet of the rich amine liquid in the cathode chamber 501 of the electrolytic cell 5.

[0033] In some embodiments, the cathode electrode 5011 is a porous conductive substrate supported on an oxygen reduction catalyst (e.g., carbon paper-supported Pt / C catalyst, etc.), and the surface of the cathode electrode 5011 is provided with serpentine oxygen channels or grid-like oxygen channels (not shown in the figure) to introduce humidified oxygen (RH>95%) and ensure sufficient contact with the amine-rich liquid. The amine-rich liquid contacts the cathode electrode and the humidified oxygen in the cathode chamber, where an oxygen reduction reaction (ORR reaction) occurs, generating heat in situ and producing OH-. - This causes CO2 to desorb from the amine-rich solution, thereby regenerating the amine solution; And / or, the anode electrode 5021 is an IrO2 / Ti electrode, which carries out the water oxidation reaction (2H2O→O2↑+4H) in the anode chamber. + +4e - ), in order to maintain charge balance; And / or, the separation membrane 503 is an anion exchange membrane to separate the cathode chamber 501 from the anode chamber 502 and maintain ion conduction.

[0034] In some embodiments, the gas supply assembly 6 further includes a gas flow controller 603, which is disposed on the connecting pipeline between the oxygen supply device 601 and the cathode chamber 501 of the electrolytic cell 5.

[0035] In some embodiments, the system further includes an expansion valve 8, which is disposed on the connecting pipe between the top outlet of the cathode chamber 501 of the electrolytic cell 5 and the inlet of the gas-liquid separator 9. The expansion valve 8 is used to reduce and regulate the pressure of the gas-liquid mixture desorbed from the cathode chamber 501, so that the pressure is more stable when it enters the downstream gas-liquid separation unit, which facilitates subsequent separation and collection.

[0036] In some embodiments, the defogging assembly includes at least two defogging devices arranged vertically at intervals (e.g., Figure 1 The first demister 901 and the second demister 902 in the middle.

[0037] Furthermore, the demister is made of polytetrafluoroethylene (PTFE). Since the desorbed gas obtained in the electrochemical desorption unit may contain droplets of alkaline and corrosive amine solution, using a PTFE demister can effectively prevent metal corrosion and material aging, while reducing solvent loss caused by the escape of amine solution with the gas.

[0038] Secondly, embodiments of the present invention also propose a method for oxygen reduction-assisted electrochemical carbon capture and desorption, implemented using the system described in the first aspect, comprising the following steps: (1) The flue gas is introduced into the packed absorption tower of the absorption unit and comes into countercurrent contact with the ammonium solution to achieve the absorption of carbon dioxide and form a rich amine liquid; (2) The rich amine solution is transported to the cathode chamber of the electrochemical desorption unit and an oxygen reduction reaction is carried out under the action of an applied voltage to obtain a first lean amine solution and a gas-liquid mixture composed of carbon dioxide and amine liquid mist. (3) The first lean amine solution and the gas-liquid mixture are transported together to the gas-liquid separation unit for gas-liquid separation to obtain high-purity carbon dioxide and the second lean amine solution, and the second lean amine solution is recycled back to the absorption unit.

[0039] In some embodiments, in step (2), the oxygen reduction reaction is carried out at an applied voltage of 0.6V and a current density of 80mA / cm². 2 The oxygen reduction reaction was carried out under the following conditions, and the reaction temperature was 65±2℃. And / or, in step (3), the purity of high-purity carbon dioxide is >99.2%.

[0040] As a specific exemplary embodiment, this embodiment provides a method for oxygen reduction-assisted electrochemical carbon capture and desorption, which is implemented using the aforementioned oxygen reduction-assisted electrochemical carbon capture and desorption system, and includes the following steps: (1) Flue gas enters the packed absorber from the bottom flue gas inlet on one side of the packed absorber and passes through the packing layer from bottom to top after being evenly distributed by the gas distributor. At the same time, amine solution enters the packed absorber from the top lean amine liquid inlet on the other side of the packed absorber and is evenly sprayed by the liquid distributor. It comes into countercurrent contact with the flue gas to absorb carbon dioxide in the flue gas and obtain clean flue gas and rich amine liquid. The clean flue gas is discharged through the top clean flue gas outlet on one side of the packed absorber, and the rich amine liquid is discharged through the bottom rich amine liquid outlet on the other side of the packed absorber and is transported to the rich amine liquid storage tank through the pipeline. (2) The rich amine solution in the storage tank is stably transported to the cathode chamber of the electrolytic cell (containing 0.5M Na2SO4 electrolyte) at a flow rate of 2L / min. The rich amine solution reacts with the cathode electrode (carbon paper supported Pt / C catalyst, 0.2mg / cm³). 2 Ensure full contact, and simultaneously introduce humidified oxygen (oxygen flow rate controlled at 50 mL / min, purity >99.5%) into the oxygen channel of the cathode electrode, while applying an external voltage (voltage 0.6V, current density 80 mA / cm²). 2 Under the influence of ) an oxygen reduction reaction occurs, generating OH in situ. - It also releases heat of reaction, and the generated OH -The reaction neutralizes the protons in the amine salt and reduces the stability of bicarbonate ions in the solution, causing carbon dioxide to desorb from the amine-rich solution. The heat released by the reaction is used to increase the local temperature, thereby further promoting carbon dioxide desorption. At the same time, a water oxidation reaction occurs in the anode chamber (filled with 1M H2SO4) to maintain the charge balance of the system, ultimately obtaining the first amine-lean solution and a gas-liquid mixture composed of carbon dioxide and amine liquid mist. (3) The first lean amine solution and the gas-liquid mixture are depressurized to 0.1 MPa by an expansion valve and then sent to a gas-liquid separation unit for gas-liquid separation. The high-purity carbon dioxide gas (purity > 99.2%) obtained by separation is discharged through the top outlet of the gas-liquid separator, and the second lean amine solution obtained by separation is discharged through the bottom outlet of the gas-liquid separator and transported through a pipeline to a packed absorption tower for recycling. In this way, while obtaining high-purity carbon dioxide products, the amine solution can also be recycled and regenerated, and the energy consumption is low.

[0041] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0042] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0043] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0044] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0045] In this invention, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0046] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A system for oxygen reduction-assisted electrochemical carbon capture and desorption, characterized in that, The system includes an adsorption unit, an amine-rich liquid delivery unit, an electrochemical desorption unit, a gas and power supply unit, and a gas-liquid separation unit. The adsorption unit includes a packed absorption tower, which is used to capture carbon dioxide from flue gas using an amine solution. The rich amine liquid conveying unit includes a rich amine liquid storage tank. The inlet of the rich amine liquid storage tank is connected to the rich amine liquid outlet of the packed absorption tower, and the outlet of the rich amine liquid storage tank is connected to the rich amine liquid inlet of the cathode chamber of the electrochemical desorption unit, for conveying the rich amine liquid formed in the adsorption unit to the cathode chamber of the electrochemical desorption unit. The electrochemical desorption unit includes an electrolytic cell, which includes a cathode chamber and an anode chamber. The cathode chamber and the anode chamber are separated by a separation membrane. The cathode chamber is equipped with a cathode electrode for performing an oxygen reduction reaction to desorb carbon dioxide from the amine-rich solution. The anode chamber is equipped with an anode electrode for performing a water oxidation reaction to maintain the charge balance of the system. The gas supply and power supply unit includes a gas supply component and a power supply component. The gas supply component includes an oxygen supply device and a humidifier, which are used to continuously supply high-humidity oxygen to the cathode chamber of the electrochemical desorption unit. The power supply component includes a DC power supply and electrode connection terminals, which are used to provide a stable voltage to the electrochemical desorption unit. The gas-liquid separation unit includes a gas-liquid separator and a demisting component. The demisting component is disposed inside the gas-liquid separator. The inlet of the gas-liquid separator is connected to the top gas outlet of the cathode chamber of the electrochemical desorption unit and to the bottom amine-deficient liquid outlet of the cathode chamber of the electrochemical desorption unit. The amine-deficient liquid outlet of the gas-liquid separator is connected to the amine-deficient liquid inlet of the adsorption unit.

2. The oxygen reduction-assisted electrochemical carbon capture and desorption system according to claim 1, characterized in that, The packed absorption tower includes a gas distributor, a packing layer, and a liquid distributor arranged sequentially from bottom to top, and the packing layer is filled with an amine solution.

3. The oxygen reduction-assisted electrochemical carbon capture and desorption system according to claim 1, characterized in that, The rich amine liquid conveying unit also includes a corrosion-resistant circulating pump and a flow regulating valve. The corrosion-resistant circulating pump and the flow regulating valve are respectively installed on the connecting pipeline between the outlet of the rich amine liquid storage tank and the inlet of the rich amine liquid in the cathode chamber of the electrolytic cell.

4. The oxygen reduction-assisted electrochemical carbon capture and desorption system according to claim 1, characterized in that, The cathode electrode is a porous conductive substrate supported on an oxygen reduction catalyst, and the surface of the cathode electrode is provided with serpentine oxygen channels or grid-like oxygen channels. And / or, the anode electrode is an IrO2 / Ti electrode; And / or, the separation membrane is an anion exchange membrane.

5. The oxygen reduction-assisted electrochemical carbon capture and desorption system according to claim 1, characterized in that, The gas supply assembly also includes a gas flow controller, which is installed on the connecting pipeline between the oxygen supply device and the cathode chamber of the electrolytic cell.

6. The oxygen reduction-assisted electrochemical carbon capture and desorption system according to claim 1, characterized in that, The system also includes an expansion valve, which is installed on the connecting pipe between the top gas outlet of the cathode chamber of the electrolytic cell and the inlet of the gas-liquid separator.

7. The oxygen reduction-assisted electrochemical carbon capture and desorption system according to claim 1, characterized in that, The defogging assembly includes at least two defogging devices arranged vertically at intervals.

8. The oxygen reduction-assisted electrochemical carbon capture and desorption system according to claim 7, characterized in that, The demister is made of polytetrafluoroethylene.

9. A method for oxygen reduction-assisted electrochemical carbon capture and desorption, implemented using the system described in any one of claims 1-8, characterized in that, The method includes the following steps: (1) The flue gas is introduced into the packed absorption tower of the absorption unit and comes into countercurrent contact with the ammonium solution to achieve the absorption of carbon dioxide and form a rich amine liquid; (2) The rich amine solution is transported to the cathode chamber of the electrochemical desorption unit and an oxygen reduction reaction is carried out under the action of an applied voltage to obtain a first lean amine solution and a gas-liquid mixture composed of carbon dioxide and amine liquid mist. (3) The first lean amine solution and the gas-liquid mixture are transported together to the gas-liquid separation unit for gas-liquid separation to obtain high-purity carbon dioxide and the second lean amine solution, and the second lean amine solution is recycled back to the absorption unit.

10. The method for oxygen reduction-assisted electrochemical carbon capture and desorption according to claim 9, characterized in that, In step (2), the oxygen reduction reaction is carried out under an applied voltage of 0.6V and a current density of 80mA / cm². 2 The oxygen reduction reaction was carried out under the following conditions, and the reaction temperature was 65±2℃. And / or, in step (3), the purity of the high-purity carbon dioxide is >99.2%.

Images