Electrolytic hydrogen production system coupled with capturing carbon dioxide from flue gas

Abstract

An electrolytic hydrogen production system coupled with capturing carbon dioxide from flue gas. The system comprises an absorption device (1), an electrolytic hydrogen production device (2), a first gas-liquid separation device (3) and a second gas-liquid separation device (4). The electrolytic hydrogen production device (2) comprises an anode chamber (21), an intermediate chamber (22) and a cathode chamber (23), which are separated by anion exchange membranes (24). In addition, the present invention further relates to a method for using the electrolytic hydrogen production system coupled with capturing carbon dioxide from flue gas. The method comprises: absorbing carbon dioxide from flue gas by using the absorption device (1); allowing the obtained absorption liquid to enter the anode chamber (21), so as to obtain a carbon-dioxide-containing gas-liquid mixture; allowing the gas-liquid mixture to enter the first gas-liquid separation device (3) to undergo separation, so as to obtain carbon dioxide and a first separation liquid; allowing the first separation liquid to enter the intermediate chamber (22), so as to realize the regeneration of the absorbent under the action of ion exchange; and returning the regenerated absorbent to the absorption device (1) again to continue the absorption of carbon dioxide.

Description

A flue gas carbon dioxide capture coupled with electrolysis hydrogen production system

[0001] The present disclosure claims priority to the Chinese patent application No. 202411301930.0, filed on September 18, 2024, and entitled "Electrochemical carbon dioxide capture system coupled with high-purity hydrogen production and method", the entire content of which is incorporated herein by reference. TECHNICAL FIELD

[0002] The present disclosure belongs to the technical field of gas purification and separation, and particularly relates to a flue gas carbon dioxide capture coupled with electrolysis hydrogen production system and method. BACKGROUND

[0003] Carbon dioxide (CO2) is the main greenhouse gas causing global climate warming, and the capture, utilization and storage of CO2 have become one of the hot topics of international concern. The CO2 emissions from coal-fired power generation in China account for about 50% of the total industrial emissions, and the capture and separation of CO2 from flue gas in coal-fired power plants is an important field of greenhouse gas emission reduction. In addition, there are also a large number of CO2 capture or separation processes in the fields of steelmaking, cement, chemical industry (such as synthetic ammonia, hydrogen production, natural gas purification) and the like. The main methods for capturing CO2 include absorption, adsorption, membrane separation, low-temperature separation and the like, among which the absorption method is the most mature and promising CO2 capture and separation technology for large-scale commercial application.

[0004] The existing CO2 absorption method for capture and separation technology has high energy consumption and operating cost in the application process, especially the steam heat energy consumed for the regeneration of the absorbent accounts for a large proportion of the entire system energy consumption, which does not conform to the concept of green environmental protection. In addition, in the electrolysis regeneration link, the consumed electric energy is only used for the regeneration of the absorbent, and the energy utilization efficiency is low.

[0005] While capturing and separating carbon dioxide, oxygen and hydrogen are also produced, among which hydrogen is also a target gas. However, the existing CO2 absorption method for capture and separation does not purify and collect the produced hydrogen, which wastes resources. Moreover, after mixing with the circulating solution, the produced hydrogen is mixed with oxygen in the anode chamber, which is prone to explosion risk, and there is a safety hazard.

[0006] In view of the above problems, it is necessary to provide a flue gas carbon dioxide capture coupled with electrolysis hydrogen production system and method which is reasonable in design and effectively solves the above problems.

[0007] CONTENT

[0008] The present disclosure aims to at least solve one of the technical problems existing in the prior art, and provides a flue gas carbon dioxide capture coupled with electrolysis hydrogen production system and method.

[0009] An aspect of the present disclosure provides a flue gas carbon dioxide capture coupled electrolytic hydrogen production system, comprising an absorption device, an electrolytic hydrogen production device, a first gas-liquid separation device and a second gas-liquid separation device; the absorption device is provided with an absorbent and is configured to absorb carbon dioxide, the electrolytic hydrogen production device comprises an anode chamber, an intermediate chamber and a cathode chamber which are arranged by an anion exchange membrane, wherein the anode chamber adopts an oxygen evolution electrode and the cathode chamber adopts a hydrogen evolution electrode; a first inlet of the absorption device is configured to communicate with flue gas containing carbon dioxide, a first outlet of the absorption device is connected to an inlet of the anode chamber through an absorption liquid pipeline, an outlet of the anode chamber is connected to an inlet of the first gas-liquid separation device through a gas-liquid mixture pipeline, a first outlet of the first gas-liquid separation device is connected to an inlet of the intermediate chamber through a first separation liquid pipeline, an outlet of the intermediate chamber is connected to a second inlet of the absorption device through an absorbent pipeline to realize the regeneration and circulation of the absorbent; an inlet of the second gas-liquid separation device is connected to an outlet of the cathode chamber through a hydrogen-containing solution pipeline, a first outlet of the second gas-liquid separation device is connected to an inlet of the cathode chamber through a second separation liquid pipeline, and a second outlet of the second gas-liquid separation device is connected through a first exhaust pipeline to realize the independent separation and discharge of hydrogen; a second outlet of the first gas-liquid separation device is connected to a second exhaust pipeline to discharge separated carbon dioxide, and a second outlet of the absorption device is connected to a purified gas pipeline to discharge purified gas.

[0010] Another aspect of the present disclosure provides a flue gas carbon dioxide capture coupled electrolytic hydrogen production method, which uses the flue gas carbon dioxide capture coupled electrolytic hydrogen production system described above, and the method comprises: delivering flue gas containing carbon dioxide to the absorption device, absorbing carbon dioxide in the flue gas by the absorbent in the absorption device to obtain absorption liquid and purified gas; delivering the absorption liquid to the anode chamber of the electrolytic hydrogen production device to obtain a gas-liquid mixture containing carbon dioxide under the action of the oxygen evolution electrode; performing gas-liquid separation treatment on the gas-liquid mixture containing carbon dioxide by the first gas-liquid separation device to obtain carbon dioxide gas and first separation liquid, discharging the separated carbon dioxide and delivering the separation liquid to the intermediate chamber, and the separation liquid in the intermediate chamber exchanges ions through the anion exchange membrane to obtain absorbent, realizing the regeneration of the absorbent, and delivering the regenerated absorbent to the absorption device to continue the absorption of carbon dioxide; delivering the hydrogen-containing solution of the cathode chamber to the first gas-liquid separation device to obtain hydrogen and second separation liquid, discharging the separated hydrogen through a first exhaust pipeline and delivering the second separation liquid to the inlet of the cathode chamber to realize the independent separation and discharge of hydrogen.

[0011] The system of the present disclosure couples the absorption and capture process of carbon dioxide in flue gas with the process of hydrogen production by electrolysis, purifies and collects hydrogen while capturing carbon dioxide, improves energy efficiency, saves energy consumption, saves operation cost, and meets the concept of green environmental protection; the purification and collection of hydrogen are carried out separately in the cathode chamber and do not participate in the carbon dioxide capture system, which can avoid the risk of explosion of hydrogen mixed with the absorption liquid and mixed with oxygen in the anode chamber, and increase the safety of the carbon dioxide capture and hydrogen production process. BRIEF DESCRIPTION OF DRAWINGS

[0012] Fig. 1 is a structural schematic diagram of a flue gas carbon dioxide capture coupled electrolysis hydrogen production system according to an embodiment of the present disclosure;

[0013] Fig. 2 is a flow schematic diagram of a flue gas carbon dioxide capture coupled electrolysis hydrogen production method according to another embodiment of the present disclosure. DETAILED DESCRIPTION

[0014] In order for those skilled in the art to better understand the technical solutions of the present disclosure, the present disclosure will be further described in detail below in combination with the drawings and specific embodiments.

[0015] As shown in Fig. 1, one aspect of the present disclosure provides a flue gas carbon dioxide capture coupled electrolysis hydrogen production system, which comprises an absorption device 1, an electrolysis hydrogen production device 2, a first gas-liquid separation device 3 and a second gas-liquid separation device 4.

[0016] The absorption device 1 is provided with an absorbent for absorbing carbon dioxide, and the electrolysis hydrogen production device 2 comprises an anode chamber 21, an intermediate chamber 22 and a cathode chamber 23 which are arranged separately by an anion exchange membrane 24, wherein the anode chamber 21 adopts an oxygen evolution electrode and can generate oxygen in the anode chamber 21; and the cathode chamber 23 adopts a hydrogen evolution electrode and can generate hydrogen in the cathode chamber 23.

[0017] It should be noted that the absorbent can be an ammonia-containing solution, but the type of absorbent is not limited to ammonia, and can also be organic amine, amino acid, etc., which can be selected according to actual needs. In this embodiment, the absorbent is taken as an ammonia-containing solution as an example for illustration.

[0018] It should be further noted that the oxygen evolution electrode can be but is not limited to a ruthenium oxide electrode, an iridium oxide electrode, a nickel-iron alloy electrode, a nickel-iron oxide electrode, etc. The hydrogen evolution electrode can be but is not limited to a platinum-carbon electrode, a platinum-ruthenium-carbon electrode, a nickel-molybdenum alloy electrode, a nickel-molybdenum oxide electrode, etc. The materials of the oxygen evolution electrode and the hydrogen evolution electrode are not limited in this embodiment and can be selected according to actual needs.

[0019] The first inlet of the absorption device 1 is arranged to communicate with the flue gas containing carbon dioxide, the first outlet of the absorption device 1 is connected to the inlet of the anode chamber 21 through the absorption liquid pipeline 51, the outlet of the anode chamber 21 is connected to the inlet of the first gas-liquid separation device 3 through the gas-liquid mixture pipeline 52, the first outlet of the first gas-liquid separation device 3 is connected to the inlet of the intermediate chamber 22 through the first separation liquid pipeline 53, and the outlet of the intermediate chamber 22 is connected to the second inlet of the absorption device 1 through the absorbent pipeline 54, so as to realize the regeneration and circulation of the absorbent.

[0020] Specifically, as shown in FIG. 1, the flue gas containing carbon dioxide enters the absorption device 1 through the first inlet of the absorption device 1, and the absorbent in the absorption device 1 absorbs the carbon dioxide to obtain absorption liquid and purified gas. The absorption liquid is a liquid with high carbon dioxide load obtained after the absorbent absorbs the carbon dioxide, and the purified gas is the gas obtained after the flue gas is removed of the carbon dioxide.

[0021] The absorption liquid enters the anode chamber 21 through the absorption liquid pipeline 51, and the absorption liquid generates oxygen at the oxygen evolution electrode in the anode chamber 21. The reaction of the oxygen evolution electrode is: 4OH - -4e - =O 2 ↑+2H2O, and the reaction of the hydrogen evolution electrode is: 4H2O+4e - =2H2↑+4OH - The concentration of OH - near the oxygen evolution electrode decreases, the acidity of the reaction solution increases, the CO2 is resolved, and the gas-liquid mixture containing carbon dioxide is obtained. The gas-liquid mixture containing carbon dioxide in the anode chamber 21 is transported to the first gas-liquid separation device 3 through the gas-liquid mixture pipeline 52 for separation to obtain carbon dioxide gas and first separation liquid. The first separation liquid enters the intermediate chamber 22 through the first separation liquid pipeline 53, and the OH produced by the hydrogen evolution cathode enters the intermediate chamber 23 through the anion exchange membrane 24, the alkalinity of the solution in the intermediate chamber 23 is enhanced, and the absorbent is obtained, so as to realize the regeneration of the absorbent. The regenerated absorbent enters the absorption device 1 from the intermediate chamber 22 through the absorbent pipeline 54, continues to provide the absorbent for the absorption device 1, and continues to realize the absorption of carbon dioxide.

[0022] As shown in FIG. 1, the inlet of the second gas-liquid separation device 4 is connected to the outlet of the cathode chamber 23 through the hydrogen-containing solution pipeline 55, the first outlet of the second gas-liquid separation device 4 is connected to the inlet of the cathode chamber 23 through the second separation liquid pipeline 56, and the second outlet of the second gas-liquid separation device 4 is connected through the first exhaust pipeline 57, so as to realize the independent separation and discharge of hydrogen.

[0023] The second gas-liquid separation device 4 is a gas-liquid separator in this embodiment, which separates and purifies the hydrogen-containing solution to obtain purified hydrogen. Specifically, the hydrogen-containing solution generated in the cathode chamber 23 is transported to the second gas-liquid separation device 4 through the hydrogen-containing solution pipeline 55, and the second gas-liquid separation device 4 separates and purifies the hydrogen-containing solution to obtain hydrogen and a second separated solution. The obtained hydrogen is discharged through the first exhaust pipeline 57 for further hydrogen collection. The obtained second separated solution reenters the cathode chamber 23 through the second gas-liquid separation device 4, and is subjected to hydrogen production and separation and purification again to realize independent separation and discharge of hydrogen.

[0024] In this embodiment, the purification and collection of hydrogen are performed separately in the cathode chamber and do not participate in the carbon dioxide capture system, which can avoid the risk of explosion caused by mixing of hydrogen with the absorption solution and mixing of hydrogen with oxygen in the anode chamber, and increase the safety in the process of carbon dioxide capture and hydrogen production.

[0025] The second outlet of the first gas-liquid separation device 3 is connected to the second exhaust pipeline 58 to discharge the separated carbon dioxide, and the second outlet of the absorption device 1 is connected to the purified gas pipeline 59 to discharge the purified gas.

[0026] The flue gas carbon dioxide capture and electrolytic hydrogen production system of the present disclosure couples the absorption and capture process of carbon dioxide in flue gas with the process of electrolytic hydrogen production, purifies and collects hydrogen to obtain hydrogen while capturing carbon dioxide, improves energy efficiency, saves energy consumption, saves operation cost, and meets the concept of green environmental protection. The purification and collection of hydrogen are performed separately in the cathode chamber and do not participate in the carbon dioxide capture system, which can avoid the risk of explosion caused by mixing of hydrogen with the absorption solution and mixing of hydrogen with oxygen in the anode chamber, and increase the safety in the process of carbon dioxide capture and hydrogen production.

[0027] For example, as shown in FIG. 1, the first gas-liquid separation device 3 includes a flash tank 31 and a condenser 32. The gas-liquid mixture inlet of the flash tank 31 is connected to the outlet of the anode chamber 21, the condenser 32 is connected to the condensate gas outlet of the flash tank 31, the condensate liquid inlet of the flash tank 31 is connected to the condensate liquid outlet of the condenser 32, and the inlet of the intermediate chamber 22 is connected to the separated liquid outlet of the flash tank 31. The top of the condenser 32 is connected to the second exhaust pipeline 58 to discharge the separated carbon dioxide. The first separated liquid is a mixture of the initial separated liquid and the condensate liquid, the initial separated liquid is the liquid substance obtained by flashing in the flash tank 31, and the condensate liquid is the liquid substance obtained by condensation in the condenser 32.

[0028] In this embodiment, the gas-liquid separation unit 3 includes a flash tank 31 and a condenser 32, through which the gas-liquid mixture can be separated, the loss of ammonia can be reduced, and the energy consumption of the entire system can be reduced.

[0029] As shown in FIG. 1, the flue gas carbon dioxide capture coupled with electrolysis hydrogen production system of the present disclosure further includes a rinsing device 5. The first inlet of the rinsing device 5 is connected to the second outlet of the absorption device 1 through a purified gas pipeline 59. The second inlet of the rinsing device 5 is connected to a rinsing water source. The first outlet of the rinsing device 5 is connected to a gas discharge pipeline.

[0030] Specifically, the purified gas generated in the absorption device 1 still contains ammonia. The purified gas containing ammonia is transported to the rinsing device 5 through the purified gas pipeline 59, and the rinsing water source enters the rinsing device 5 through the second inlet to rinse the purified gas containing ammonia, so as to separate and recover the residual ammonia. The separated ammonia exists in the form of ammonia-containing rinsing liquid, and the absorbent and the gas to be discharged are obtained. The gas to be discharged is discharged through the gas discharge pipeline 46.

[0031] As shown in FIG. 1, the flue gas carbon dioxide capture coupled with electrolysis hydrogen production system of the present disclosure includes a desulfurization device 6. The first inlet of the desulfurization device 6 is connected to the flue gas containing carbon dioxide. The flue gas containing carbon dioxide first enters the desulfurization device 6 for flue gas desulfurization pretreatment, and a desulfurization liquid is obtained.

[0032] The first outlet of the desulfurization device 6 is connected to the first inlet of the absorption device 1. The flue gas after desulfurization treatment enters the absorption device 1 for carbon dioxide absorption and capture.

[0033] The second inlet of the desulfurization device 6 is connected to the second outlet of the rinsing device 5. The separated ammonia in the rinsing device 5 is transported to the desulfurization device 6 in the form of ammonia-containing rinsing liquid.

[0034] The backflow outlet of the desulfurization device 6 is connected to the backflow inlet of the rinsing device 5. The height of the backflow inlet is lower than the height of the second inlet.

[0035] Specifically, the separated ammonia combines with sulfur dioxide in the flue gas to exist in the form of desulfurization liquid. The desulfurization liquid that does not reach the saturated state is backflowed from the desulfurization device 6 to the rinsing device 5 to rinse the purified gas, and is transported from the rinsing device 5 to the desulfurization device 6 in the form of ammonia-containing rinsing liquid, forming a circulation loop.

[0036] It should be noted that the purified gas can be rinsed with circulating desulfurization liquid, or rinsed with externally supplemented water, or rinsed with desulfurization liquid and externally supplemented water together, which can be selected according to actual needs.

[0037] Exemplarily, as shown in FIG. 1, the flue gas carbon dioxide capture coupled with electrolytic hydrogen production system of the present disclosure further comprises a recovery device 7, an inlet of the recovery device 7 being in communication with a reflux outlet of the desulfurization device 6, so that when the desulfurization liquid in the desulfurization unit reaches saturation, the liquid substance in the desulfurization device 6 is transported into the recovery device 7 for treatment.

[0038] Specifically, when the desulfurization liquid reaches saturation, the liquid substance in the desulfurization device 6 can be transported into the recovery device 7 for treatment, and the utilization of sulfur dioxide is obtained, for example, the utilization of sulfur dioxide can be an ammonium sulfate fertilizer product. The recovery and reuse of the desulfurization liquid is achieved by the recovery device 7, thereby saving resources.

[0039] Exemplarily, as shown in FIG. 1, the flue gas carbon dioxide capture coupled with electrolytic hydrogen production system of the present disclosure further comprises a first heat exchange device 8, the first heat exchange device 8 being in communication with the elution device 5 and the desulfurization device 6, respectively, and being arranged as heat exchange between the elution device 5 and the desulfurization device 6.

[0040] Specifically, the ammonia-containing elution liquid and the desulfurization liquid can be heat exchanged by the first heat exchange device 8, and the heat exchange of the ammonia-containing elution liquid and the desulfurization liquid is carried out by the first heat exchange device 8, which is arranged to transfer the heat of the desulfurization liquid to the ammonia-containing elution liquid. In addition, after the heat exchange, the ammonia-containing elution liquid can be further heated by a heating assembly during the process of being transported to the desulfurization device 6, so as to promote the desulfurization process in the desulfurization device 6; after the heat exchange, the desulfurization liquid can be further cooled by a cooling assembly during the process of being transported to the elution device 5.

[0041] In this embodiment, the first heat exchange device improves the heat utilization rate of the entire system and saves energy consumption.

[0042] Exemplarily, as shown in FIG. 1, the flue gas carbon dioxide capture coupled with electrolytic hydrogen production system of the present disclosure further comprises a second heat exchange device 9, the second heat exchange device 9 being in communication with the absorption device 1 and the electrolytic hydrogen production device 2, respectively, and being arranged as heat exchange between the absorption device 1 and the electrolytic hydrogen production device 2.

[0043] Specifically, the second heat exchange device 9 comprises a cold end inlet, a cold end outlet, a hot end inlet and a hot end outlet. The cold end inlet of the second heat exchange device 9 is in communication with the second outlet of the absorption device 1, the hot end outlet of the second heat exchange device 9 is in communication with the inlet of the anode chamber 21, the hot end inlet of the second heat exchange device 9 is in communication with the outlet of the intermediate chamber 23, and the cold end outlet of the second heat exchange device 9 is in communication with the second inlet of the absorption device 1.

[0044] In the embodiment, the heat exchange between the absorbent and the absorption liquid is only through the second heat exchange device 9, and the heat of the absorbent is transferred to the absorption liquid. The absorbent and the absorption liquid are isolated from each other in the second heat exchange device 9. The conveying channel between the cold end outlet of the second heat exchange device 9 and the absorbent inlet of the absorption device 1 is configured to convey the absorbent to the absorption device 1, and a cooling assembly can be installed on the conveying channel. The conveying channel between the hot end outlet of the second heat exchange device 9 and the inlet of the anode chamber 21 is configured to convey the absorption liquid to the anode chamber 21, and a heating assembly can be installed on the conveying channel.

[0045] For example, the absorption device includes an absorption part, a condensation part, and a separation plate separating the absorption part and the condensation part. The absorption part is located at the bottom of the absorption device, and the condensation part is located at the top of the absorption device. The separation plate allows gas to pass through and blocks liquid substances from passing through. The material of the separation plate can be PTFE film, and preferably, the material of the separation plate can be Teflon PTFE film.

[0046] The flue gas inlet of the absorption part is configured to communicate with the flue gas containing carbon dioxide, and the absorbent inlet of the absorption part is configured to communicate with the outlet of the intermediate chamber. The absorption liquid outlet of the condensation part is connected to the absorption liquid pipeline, and the gas outlet of the condensation part is connected to the purified gas pipeline.

[0047] It should be noted that the specific structural features of the absorption device are not limited in the embodiment, and can be selected according to actual needs.

[0048] As shown in FIG. 2, another aspect of the present disclosure provides a flue gas carbon dioxide capture coupled with electrolysis hydrogen production method S100, which uses the flue gas carbon dioxide capture coupled with electrolysis hydrogen production system described above. The specific structure of the flue gas carbon dioxide capture coupled with electrolysis hydrogen production system has been described in detail above, and will not be described again here. The method S100 includes:

[0049] S110, conveying the flue gas containing carbon dioxide to the absorption device, and absorbing the carbon dioxide in the flue gas by the absorbent in the absorption device to obtain absorption liquid and purified gas.

[0050] Specifically, the ammonia-containing solution absorbent in the absorption device 1 can contain a supporting electrolyte, which can be potassium chloride, sodium chloride, sodium sulfate, etc. In addition, some additives, such as tetraethylammonium chloride, tetrapropylammonium chloride, and other surfactants, can also be added to the absorbent in the absorption unit 1. The absorption liquid is a high-carbon dioxide-loaded liquid obtained after the absorbent absorbs carbon dioxide, and the purified gas is the gas obtained after the flue gas is removed of carbon dioxide.

[0051] S120, delivering the absorption liquid into the anode chamber of the electrolytic hydrogen production device, and obtaining a gas-liquid mixture containing carbon dioxide through the action of the oxygen evolution electrode.

[0052] Specifically, the absorption liquid enters the anode chamber 21 through the absorption liquid pipeline 51, and the absorption liquid generates oxygen at the oxygen evolution electrode in the anode chamber 21, and the oxygen evolution electrode reacts: 4OH - -4e-=O 2 ↑+2H2O, and the hydrogen evolution electrode reacts: 4H2O+4e-=2H2↑+4OH - The concentration of OH - near the oxygen evolution electrode decreases, the acidity of the reaction solution increases, CO2 is resolved, and a gas-liquid mixture containing carbon dioxide is obtained.

[0053] S130, the gas-liquid mixture containing carbon dioxide is separated by the first gas-liquid separator, and carbon dioxide gas and a first separated liquid are obtained, the separated carbon dioxide is discharged, and the separated liquid is delivered to the intermediate chamber, and the separated liquid in the intermediate chamber is ion exchanged through the anion exchange membrane to obtain an absorbent, regenerate the absorbent, and deliver the regenerated absorbent to the absorption device to continue absorbing carbon dioxide.

[0054] Specifically, the gas-liquid mixture containing carbon dioxide in the anode chamber 21 is delivered to the first gas-liquid separator 3 through the gas-liquid mixture pipeline 52 for separation, and carbon dioxide gas and a first separated liquid are obtained. The first separated liquid enters the intermediate chamber 22 through the first separated liquid pipeline 53, and the OH produced by the hydrogen evolution cathode enters the intermediate chamber 23 through the anion exchange membrane 24, the alkalinity of the solution in the intermediate chamber 23 is enhanced, and the absorbent is obtained, and the absorbent is regenerated. The regenerated absorbent enters the absorption device 1 from the intermediate chamber 22 through the absorbent pipeline 54, continues to provide the absorption device 1 with absorbent, and continues to absorb carbon dioxide.

[0055] S140, delivering the hydrogen-containing solution in the cathode chamber to the first gas-liquid separator, obtaining hydrogen gas and a second separated liquid, discharging the separated hydrogen gas through the first exhaust pipeline, and delivering the second separated liquid to the inlet of the cathode chamber to realize independent separation and discharge of hydrogen gas.

[0056] In the embodiment, the second gas-liquid separation device 4 is a gas-liquid separator, which separates and purifies the hydrogen-containing solution to obtain purified hydrogen. Specifically, the hydrogen-containing solution generated in the cathode chamber 23 is transported to the second gas-liquid separation device 4 through the hydrogen-containing solution pipeline 55, and the second gas-liquid separation device 4 separates and purifies the hydrogen-containing solution to obtain hydrogen and a second separated solution. The obtained hydrogen is discharged through the first exhaust pipeline 57 for further hydrogen collection. The obtained second separated solution reenters the cathode chamber 23 through the second gas-liquid separation device 4, and is subjected to hydrogen production and separation and purification again to realize independent separation and discharge of hydrogen.

[0057] The flue gas carbon dioxide capture coupled with electrolysis hydrogen production method of the present disclosure couples the absorption and capture process of carbon dioxide in flue gas with the process of electrolysis hydrogen production, and purifies and collects hydrogen while capturing carbon dioxide, thereby improving energy efficiency, saving energy consumption, saving operation cost, and conforming to the concept of green environmental protection; the purification and collection of hydrogen are performed separately in the cathode chamber and do not participate in the carbon dioxide capture system, which can avoid the risk of explosion caused by mixing of hydrogen and absorption liquid and mixing of hydrogen and oxygen in the anode chamber, and increase the safety in the processes of carbon dioxide capture and hydrogen production.

[0058] It can be understood that the above embodiments are only exemplary embodiments for illustrating the principles of the present disclosure, and the present disclosure is not limited thereto. Various modifications and improvements can be made by those skilled in the art without departing from the spirit and essence of the present disclosure, and these modifications and improvements are also considered to be within the protection scope of the present disclosure.

Claims

1. An electrochemical carbon dioxide capture system coupled with high-purity hydrogen production, comprising an absorption device, an electrolytic hydrogen production device, a first gas-liquid separation device and a second gas-liquid separation device; The absorption device is provided with an absorbent for absorbing carbon dioxide, and the electrolytic hydrogen production device comprises an anode chamber, an intermediate chamber and a cathode chamber which are arranged in separation by an anion exchange membrane, wherein, the anode chamber adopts an oxygen evolution electrode, and the cathode chamber adopts a hydrogen evolution electrode; a first inlet of the absorption device is arranged in communication with flue gas containing carbon dioxide, a first outlet of the absorption device is connected to an inlet of the anode chamber through an absorption liquid pipeline, an outlet of the anode chamber is connected to an inlet of the first gas-liquid separation device through a gas-liquid mixture pipeline, a first outlet of the first gas-liquid separation device is connected to an inlet of the intermediate chamber through a first separated liquid pipeline, an outlet of the intermediate chamber is connected to a second inlet of the absorption device through an absorbent pipeline, so as to realize regeneration and circulation of the absorbent; an inlet of the second gas-liquid separation device is connected to an outlet of the cathode chamber through a hydrogen-containing solution pipeline, a first outlet of the second gas-liquid separation device is connected to an inlet of the cathode chamber through a second separated liquid pipeline, and a second outlet of the second gas-liquid separation device is connected to a first exhaust pipeline, so as to realize independent separation and discharge of hydrogen. a second outlet of the first gas-liquid separation device is connected to a second exhaust pipeline to discharge separated carbon dioxide, and a second outlet of the absorption device is connected to a purified gas pipeline to discharge purified gas.

2. The system of claim 1, wherein, The second gas-liquid separation device is a gas-liquid separator, which separates and purifies the hydrogen-containing solution to obtain purified hydrogen.

3. The system of claim 1, wherein, The first gas-liquid separation device comprises a flash tank and a condenser; a gas-liquid mixture inlet of the flash tank is connected to an outlet of the anode chamber, a to-be-condensed gas inlet of the condenser is connected to a to-be-condensed gas outlet of the flash tank, a condensate inlet of the flash tank is connected to a condensate outlet of the condenser, and an inlet of the intermediate chamber is connected to a separated liquid outlet of the flash tank; a top of the condenser is connected to the second exhaust pipeline to discharge separated carbon dioxide.

4. The system of any one of claims 1 to 3, wherein, The system further comprises a rinsing device; a first inlet of the rinsing device is connected to a second outlet of the absorption device through the purified gas pipeline; a second inlet of the rinsing device is arranged in communication with a rinsing water source; a first outlet of the rinsing device is connected to a gas discharge pipeline.

5. The system of claim 4, wherein, The system further comprises a desulfurization device; a first inlet of the desulfurization device is arranged in communication with flue gas containing carbon dioxide, and a first outlet of the desulfurization device is connected to a first inlet of the absorption device; a second inlet of the desulfurization device is connected to a second outlet of the rinsing device; a backflow outlet of the desulfurization device is connected to a backflow inlet of the rinsing device.

6. The system of claim 5, wherein, The system further comprises a recovery device; an inlet of the recovery device is connected to the backflow outlet of the desulfurization device, so that when desulfurization liquid in the desulfurization device reaches saturation, liquid substances in the desulfurization device are transported to the recovery device for treatment.

7. The system of claim 5, wherein, The system further comprises a first heat exchange device; the first heat exchange device is connected to the rinsing device and the desulfurization device respectively, and is arranged to exchange heat between the rinsing device and the desulfurization device.

8. The system of any one of claims 1 to 3, wherein, The system further comprises a second heat exchange device; The second heat exchange device is connected to the absorption device and the electrolysis device respectively and is arranged to exchange heat between the absorption device and the electrolysis device.

9. The system of claim 8, wherein, The second heat exchange device comprises a cold end inlet, a cold end outlet, a hot end inlet and a hot end outlet. The cold end inlet of the second heat exchange device is connected to the second outlet of the absorption device, the hot end outlet of the second heat exchange device is connected to the inlet of the anode chamber, the hot end inlet of the second heat exchange device is connected to the outlet of the intermediate chamber, and the cold end outlet of the second heat exchange device is connected to the second inlet of the absorption device.

10. A flue gas carbon dioxide capture coupled with electrolysis hydrogen production process, wherein, The method comprises the following steps: delivering flue gas containing carbon dioxide to the absorption device, absorbing carbon dioxide in the flue gas by the absorbent in the absorption device to obtain absorption liquid and purified gas; delivering the absorption liquid to the anode chamber of the hydrogen production device by electrolysis to obtain a gas-liquid mixture containing carbon dioxide under the action of an oxygen evolution electrode; carrying out gas-liquid separation treatment on the gas-liquid mixture containing carbon dioxide by the first gas-liquid separation device to obtain carbon dioxide gas and first separation liquid, discharging the separated carbon dioxide and delivering the separation liquid to the intermediate chamber, regenerating the absorbent by ion exchange of the separation liquid in the intermediate chamber through the anion exchange membrane, and delivering the regenerated absorbent to the absorption device to continue the absorption of carbon dioxide; delivering the hydrogen-containing solution in the cathode chamber to the first gas-liquid separation device to obtain hydrogen gas and second separation liquid, discharging the separated hydrogen gas through the first exhaust pipeline and delivering the second separation liquid to the inlet of the cathode chamber to realize independent separation and discharge of hydrogen gas. The method comprises the following steps: delivering flue gas containing carbon dioxide to the absorption device, absorbing carbon dioxide in the flue gas by the absorbent in the absorption device to obtain absorption liquid and purified gas; delivering the absorption liquid to the anode chamber of the hydrogen production device by electrolysis to obtain a gas-liquid mixture containing carbon dioxide under the action of an oxygen evolution electrode; carrying out gas-liquid separation treatment on the gas-liquid mixture containing carbon dioxide by the first gas-liquid separation device to obtain carbon dioxide gas and first separation liquid, discharging the separated carbon dioxide and delivering the separation liquid to the intermediate chamber, regenerating the absorbent by ion exchange of the separation liquid in the intermediate chamber through the anion exchange membrane, and delivering the regenerated absorbent to the absorption device to continue the absorption of carbon dioxide; delivering the hydrogen-containing solution in the cathode chamber to the first gas-liquid separation device to obtain hydrogen gas and second separation liquid, discharging the separated hydrogen gas through the first exhaust pipeline and delivering the second separation liquid to the inlet of the cathode chamber to realize independent separation and discharge of hydrogen gas.

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