Electrochemical carbon dioxide trapping system and method prepared by coupling high-purity hydrogen

Abstract

According to the electrochemical carbon dioxide trapping system and method prepared by coupling high-purity hydrogen, the system absorbs carbon dioxide in flue gas through the absorption device, and the obtained absorption liquid enters the anode chamber to obtain a gas-liquid mixture containing carbon dioxide; the gas-liquid mixture enters the first gas-liquid separation device to be separated to obtain carbon dioxide and first separation liquid, the first separation liquid enters the middle chamber, under the action of ion exchange, regeneration of the absorbent is achieved, and the regenerated absorbent returns to the absorption device again to continue absorption of the carbon dioxide. The absorption and capture process of carbon dioxide in flue gas is coupled with the electrolytic hydrogen production process, hydrogen is collected while carbon dioxide is captured, the energy efficiency is improved, energy consumption is reduced, the operation cost is saved, and the green and environment-friendly concept is met; hydrogen purification and collection are independently carried out in the cathode chamber and do not participate in carbon dioxide capture, the risk of explosion caused by the fact that hydrogen and absorption liquid are mixed and then enter the anode chamber to be mixed with oxygen can be avoided, and safety is improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of gas purification and separation, and in particular relates to an electrochemical carbon dioxide capture system and method coupled with high-purity hydrogen preparation. Background Art

[0002] Carbon dioxide (CO2) is the main greenhouse gas that causes global warming. The capture, utilization and storage of CO2 has become one of the hot topics of international concern. CO2 emissions from coal-fired power generation in my country account for about 50% of total industrial emissions. The capture and separation of CO2 in flue gas from coal-fired power plants is an important area for greenhouse gas emission reduction. In addition, there are also a large number of CO2 capture or separation processes in industrial fields such as steelmaking, cement, and chemical industry (such as synthetic ammonia, hydrogen production, and natural gas purification). The main methods for capturing CO2 include absorption, adsorption, membrane separation, and low-temperature separation. Among them, the absorption method is currently the most mature CO2 capture and separation technology that is expected to achieve large-scale commercial application.

[0003] The existing CO2 absorption capture and separation technology has high energy consumption and operating costs during the application process. In particular, the steam heat consumed by the absorbent regeneration accounts for a large proportion of the energy consumption of the entire system, which is not in line with the concept of green environmental protection. In addition, in the electrolytic regeneration stage, the consumed electricity is only used for absorbent regeneration, and the energy utilization efficiency is low.

[0004] While capturing and separating carbon dioxide, oxygen and hydrogen are produced, of which hydrogen is also the target gas. However, the existing CO2 absorption capture and separation method does not purify and collect the produced hydrogen, which wastes resources. In addition, the produced hydrogen mixes with the circulating solution and enters the anode chamber to mix with oxygen, which is prone to explosion, posing a safety hazard.

[0005] In view of the above problems, it is necessary to propose an electrochemical carbon dioxide capture system and method coupled with high-purity hydrogen preparation that is reasonably designed and effectively solves the above problems. Summary of the invention

[0006] The present invention aims to solve at least one of the technical problems existing in the prior art and to provide an electrochemical carbon dioxide capture system and method coupled with high-purity hydrogen preparation.

[0007] One aspect of the present invention provides 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;

[0008] 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 separated by an anion exchange membrane, wherein the anode chamber adopts an oxygen evolution electrode, and the cathode chamber adopts a hydrogen evolution electrode;

[0009] The first inlet of the absorption device is used to communicate with the flue gas containing carbon dioxide, the first outlet of the absorption device is connected to the inlet of the anode chamber through an absorption liquid pipeline, the outlet of the anode chamber is connected to the inlet of the first gas-liquid separation device through a gas-liquid mixture pipeline, the first outlet of the first gas-liquid separation device is connected to the inlet of the intermediate chamber through a first separation liquid pipeline, and the outlet of the intermediate chamber is connected to the second inlet of the absorption device through an absorbent pipeline, so as to realize the regeneration cycle of the absorbent;

[0010] The inlet of the second gas-liquid separation device is connected to the outlet of the cathode chamber through a hydrogen-containing solution pipeline, the first outlet of the second gas-liquid separation device is connected to the inlet of the cathode chamber through a second separation liquid pipeline, and the second outlet of the second gas-liquid separation device is connected to the first exhaust pipeline, so as to realize independent separation and discharge of hydrogen;

[0011] The second outlet of the first gas-liquid separation device is connected to the second exhaust pipe to discharge the separated carbon dioxide, and the second outlet of the absorption device is connected to the purified gas pipeline to discharge the purified gas.

[0012] Optionally, the second gas-liquid separation device is a gas-liquid separator, which separates and purifies the hydrogen-containing solution to obtain purified hydrogen.

[0013] Optionally, the first gas-liquid separation device includes a flash tank and a condenser;

[0014] The gas-liquid mixture inlet of the flash tank is connected to the outlet of the anode chamber, the gas inlet to be condensed of the condenser is connected to the gas outlet to be condensed of the flash tank, the condensate inlet of the flash tank is connected to the condensate outlet of the condenser, and the inlet of the intermediate chamber is connected to the separated liquid outlet of the flash tank;

[0015] The top of the condenser is connected to the second exhaust pipe to discharge the separated carbon dioxide.

[0016] Optionally, a rinsing device is also included;

[0017] The first inlet of the elution device is connected to the second outlet of the absorption device through the purified gas pipeline;

[0018] The second inlet of the rinsing device is used to be connected to the rinsing water source;

[0019] The first outlet of the rinsing device is connected to the gas exhaust pipeline.

[0020] Optionally, a desulfurization device is also included;

[0021] The first inlet of the desulfurization device is used to communicate with the flue gas containing carbon dioxide, and the first outlet of the desulfurization device is connected to the first inlet of the absorption device;

[0022] The second inlet of the desulfurization device is connected to the second outlet of the elution device;

[0023] The reflux outlet of the desulfurization device is communicated with the reflux inlet of the elution device.

[0024] Optionally, a recovery device is also included;

[0025] The inlet of the recovery device is connected to the reflux outlet of the desulfurization device, so that when the desulfurization liquid in the desulfurization device reaches saturation, the liquid material in the desulfurization device is transported to the recovery device for treatment.

[0026] Optionally, it also includes a first heat exchange device;

[0027] The first heat exchange device is respectively connected to the elution device and the desulfurization device, and is used for heat exchange between the elution device and the desulfurization device.

[0028] Optionally, it also includes a second heat exchange device;

[0029] The second heat exchange device is respectively connected to the absorption device and the electrolysis device, and is used for heat exchange between the absorption device and the electrolysis device.

[0030] Optionally, the second heat exchange device includes a cold end inlet, a cold end outlet, a hot end inlet and a hot end outlet;

[0031] 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.

[0032] Another aspect of the present invention provides an electrochemical carbon dioxide capture method coupled with high-purity hydrogen production, using the electrochemical carbon dioxide capture system coupled with high-purity hydrogen production as described above, the method comprising:

[0033] The flue gas containing carbon dioxide is transported to the absorption device, and the carbon dioxide in the flue gas is absorbed by the absorbent in the absorption device to obtain an absorption liquid and a purified gas;

[0034] The absorption liquid is transported 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;

[0035] The gas-liquid mixture containing carbon dioxide is subjected to gas-liquid separation by the first gas-liquid separation device to obtain carbon dioxide gas and a first separation liquid, the separated carbon dioxide is discharged and the separation liquid is transported to the intermediate chamber, the separation liquid in the intermediate chamber is subjected to ion exchange of the anion exchange membrane to obtain an absorbent, the absorbent is regenerated, and the regenerated absorbent is transported to the absorption device to continue absorbing carbon dioxide;

[0036] The hydrogen-containing solution in the cathode chamber is transported to the first gas-liquid separation device to obtain hydrogen and a second separation liquid. The separated hydrogen is discharged through a first exhaust pipe and the second separation liquid is transported to the inlet of the cathode chamber to achieve independent separation and discharge of hydrogen.

[0037] The electrochemical carbon dioxide capture system and method for coupled high-purity hydrogen preparation of the present invention couples the absorption and capture process of carbon dioxide in flue gas with the process of electrolytic hydrogen production, purifies and collects hydrogen while capturing carbon dioxide, improves energy efficiency, saves energy consumption, saves operating costs, and complies with the concept of green environmental protection; the purification and collection of hydrogen is carried out separately in the cathode chamber and does not participate in the carbon dioxide capture system, which can avoid the risk of explosion caused by hydrogen mixing with absorption liquid and then entering the anode chamber and mixing with oxygen, thereby increasing the safety of carbon dioxide capture and hydrogen production processes. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 This is a schematic structural diagram of an electrochemical carbon dioxide capture system coupled with high-purity hydrogen preparation according to an embodiment of the present invention;

[0039] Figure 2 It is a schematic flow chart of an electrochemical carbon dioxide capture method coupled with high-purity hydrogen preparation in another embodiment of the present invention. DETAILED DESCRIPTION

[0040] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention is further described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0041] like Figure 1 As shown, one aspect of the present invention provides an electrochemical carbon dioxide capture system coupled with high-purity hydrogen production, including 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.

[0042] The absorption device 1 is provided with an absorbent for absorbing carbon dioxide. The electrolytic hydrogen production device 2 includes an anode chamber 21, an intermediate chamber 22 and a cathode chamber 23 separated by an anion exchange membrane 24, wherein the anode chamber 21 adopts an oxygen evolution electrode to produce oxygen in the anode chamber 21; the cathode chamber 23 adopts a hydrogen evolution electrode to produce hydrogen in the cathode chamber 23.

[0043] It should be noted that the absorbent may be an ammonia solution, but the absorbent is not limited to ammonia, and may also be organic amines, amino acids, etc., which may be selected according to actual needs. In this embodiment, the absorbent is an ammonia solution as an example for description.

[0044] It should be further explained that the oxygen evolution electrode may be, but 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 may be, but 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.

[0045] The first inlet of the absorption device 1 is used to be connected to 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 to realize the regeneration cycle of the absorbent.

[0046] Specifically, Figure 1 As shown, flue gas containing carbon dioxide enters the absorber 1 through the first inlet of the absorber 1, and the absorbent in the absorber 1 absorbs carbon dioxide to obtain an absorption liquid and a purified gas. The absorption liquid is a liquid with a high carbon dioxide load obtained after the absorbent absorbs carbon dioxide, and the purified gas refers to the gas obtained after the flue gas is decarbonated.

[0047] 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 of the anode chamber 21, and the oxygen evolution electrode reacts: 4OH - -4e - =O 2 ↑+2H2O, the hydrogen evolution electrode reacts: 4H2O+4e - =2H2↑+4OH - OH near the oxygen evolution electrode -The concentration decreases, the acidity of the reaction liquid increases, CO2 is resolved, and a 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 a first separated liquid. The first separated liquid enters the intermediate chamber 22 through the first separated liquid pipeline 53, and the hydrogen evolution cathode produces OH - Then, it enters the intermediate chamber 23 through the anion exchange membrane 24, and the alkalinity of the solution in the intermediate chamber 23 is enhanced to obtain an absorbent, thereby realizing the regeneration of the absorbent. The regenerated absorbent enters the absorption device 1 through the absorbent pipeline 54 from the intermediate chamber 22, and continues to provide absorbent to the absorption device 1, thereby continuing to realize the absorption of carbon dioxide.

[0048] like Figure 1 As shown, 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 to achieve independent separation and discharge of hydrogen.

[0049] Among them, in this embodiment, the second gas-liquid separation device 4 is a gas-liquid separator, and the gas-liquid separator 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 purifies and separates the hydrogen-containing solution to obtain hydrogen and a second separated liquid, wherein the obtained hydrogen is discharged through the first exhaust pipeline 57 for the next step of hydrogen collection. The obtained second separated liquid enters the cathode chamber 23 again through the second gas-liquid separation device 4, and hydrogen is prepared and separated and purified again to achieve independent separation and discharge of hydrogen.

[0050] In this embodiment, the purification and collection of hydrogen is carried out separately in the cathode chamber without participating in the carbon dioxide capture system. This can avoid the risk of hydrogen mixing with the absorption liquid and then entering the anode chamber to mix with oxygen and causing explosion, thereby increasing the safety of carbon dioxide capture and hydrogen production processes.

[0051] The second outlet of the first gas-liquid separation device 3 is connected to the second exhaust pipe 58 to discharge the separated carbon dioxide, and the second outlet of the absorption device 1 is connected to the purified gas pipe 59 to discharge the purified gas.

[0052] In the electrochemical carbon dioxide capture system coupled with high-purity hydrogen preparation of the present invention, the absorption and capture process of carbon dioxide in flue gas is coupled with the process of hydrogen production by electrolysis, and hydrogen is purified and collected while capturing carbon dioxide, thereby improving energy efficiency, saving energy consumption, saving operating costs, and complying with the concept of green environmental protection; the purification and collection of hydrogen is carried out separately in the cathode chamber and does not participate in the carbon dioxide capture system, which can avoid the risk of explosion caused by hydrogen mixing with absorption liquid and then entering the anode chamber and mixing with oxygen, thereby increasing the safety of carbon dioxide capture and hydrogen production processes.

[0053] For example, Figure 1 As shown, 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 gas inlet to be condensed of the condenser 32 is connected to the gas outlet to be condensed of the flash tank 31, the condensate inlet of the flash tank 31 is connected to the condensate 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 pipe 58 to discharge the separated carbon dioxide. Among them, the first separated liquid is a mixture of the initial separated liquid and the condensate, the initial separation liquid level is the liquid substance obtained by flash evaporation in the flash tank 31, and the condensate is the liquid substance obtained by condensation in the condenser 32.

[0054] In this embodiment, the gas-liquid separation unit 3 includes a flash tank 31 and a condenser 32. The flash tank 31 and the condenser 32 can separate the gas-liquid mixture, thereby reducing the loss of ammonia and the energy consumption of the entire system.

[0055] For example, Figure 1 As shown, the electrochemical carbon dioxide capture system coupled with high-purity hydrogen production of the present invention further includes a leaching device 5. The first inlet of the leaching device 5 is connected to the second outlet of the absorption device 1 through the purified gas pipeline 59. The second inlet of the leaching device 5 is used to be connected to the leaching water source. The first outlet of the leaching device 5 is connected to the gas exhaust pipeline.

[0056] Specifically, the purified gas generated in the absorption device 1 will contain residual ammonia. The purified gas containing ammonia is transmitted to the elution device 5 through the purified gas pipeline 59. The elution water source enters the elution device 5 through the second inlet to elute the purified gas containing ammonia, so as to separate and recover the residual ammonia. The separated ammonia exists in the form of ammonia-containing eluent to obtain an absorbent and a gas to be discharged. The gas to be discharged is discharged through the gas discharge pipeline 46.

[0057] For example, Figure 1As shown, the electrochemical carbon dioxide capture system coupled with high-purity hydrogen production of the present invention comprises a desulfurization device 6. The first inlet of the desulfurization device 6 is used to communicate with the flue gas containing carbon dioxide, and the flue gas containing carbon dioxide first enters the desulfurization device 6 for pretreatment of flue gas desulfurization to obtain a desulfurized liquid.

[0058] 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 to absorb and capture carbon dioxide.

[0059] The second inlet of the desulfurization device 6 is connected to the second outlet of the elution device 5. The ammonia separated in the elution device 5 is transported from the elution device 5 to the desulfurization device 6 in the form of an ammonia-containing eluent.

[0060] The reflux outlet of the desulfurization device 6 is connected to the reflux inlet of the elution device 5. The height of the reflux inlet is lower than the height of the second inlet.

[0061] Specifically, the separated ammonia exists in the form of desulfurization liquid after combining with sulfur dioxide in the flue gas. The desulfurization liquid that has not reached the saturated state flows back from the desulfurization device 6 to the elution device 5 to elute the purified gas, and is transported from the elution device 5 to the desulfurization device 6 along with the separated ammonia-containing eluent, forming a circulation loop.

[0062] It should be noted that the purified gas can be eluted with a circulating desulfurization liquid or with externally supplemented water. Of course, the purified gas can also be eluted with both desulfurization liquid and externally supplemented water. The choice can be made according to actual needs.

[0063] For example, Figure 1 As shown, the electrochemical carbon dioxide capture system coupled with high-purity hydrogen preparation of the present invention also includes a recovery device 7, the inlet of the recovery device 7 is connected to the reflux outlet of the desulfurization device 6, so that when the desulfurization liquid in the desulfurization unit reaches saturation, the liquid material in the desulfurization device 6 is transported to the recovery device 7 for treatment.

[0064] Specifically, when the desulfurized liquid reaches saturation, the liquid substance in the desulfurization device 6 can be transported to the recovery device 7 for processing to obtain the utilization of sulfur dioxide, such as ammonium sulfate fertilizer product. The recovery device 7 can be used to recycle the desulfurized liquid, saving resources.

[0065] For example, Figure 1 As shown, the electrochemical carbon dioxide capture system coupled with high-purity hydrogen preparation of the present invention also includes a first heat exchange device 8, which is connected to the elution device 5 and the desulfurization device 6 respectively, and is used for heat exchange between the elution device 5 and the desulfurization device 6.

[0066] Specifically, the ammonia-containing eluent and the desulfurization liquid can be heat exchanged through the first heat exchange device 8, and the heat exchange between the ammonia-containing eluent and the desulfurization liquid is performed through the first heat exchange device 8, which is used to transfer the heat of the desulfurization liquid to the ammonia-containing eluent. In addition, after the heat exchange, the ammonia-containing eluent can be further heated by the heating component during the process of being transported to the desulfurization device 6 to promote the desulfurization treatment in the desulfurization device 6; after the heat exchange, the desulfurization liquid can be further cooled by the cooling component during the process of being transported to the elution device 5.

[0067] In this embodiment, the heat utilization rate of the entire system is improved by the first heat exchange device, thereby saving energy consumption.

[0068] For example, Figure 1 As shown, the electrochemical carbon dioxide capture system coupled with high-purity hydrogen production of the present invention further includes a second heat exchange device 9, which is respectively connected to the absorption device 1 and the electrolytic hydrogen production device 2, and is used for heat exchange between the absorption device 1 and the electrolytic hydrogen production device 2.

[0069] Specifically, the second heat exchange device 9 includes 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 connected to the second outlet of the absorption device 1, the hot end outlet of the second heat exchange device 9 is connected to the inlet of the anode chamber 21, the hot end inlet of the second heat exchange device 9 is connected to the outlet of the intermediate chamber 23, and the cold end outlet of the second heat exchange device 9 is connected to the second inlet of the absorption device 1.

[0070] In this embodiment, the absorbent and the absorption liquid exchange heat 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 used to convey the absorbent to the absorption device 1, and a cooling component 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 used to convey the absorption liquid to the anode chamber 21, and a heating component can be installed on the conveying channel.

[0071] Exemplarily, the absorption device includes an absorption part, a condensation part, and an isolation plate for isolating 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 isolation plate allows gas to pass through and blocks liquid substances from passing through. The material of the isolation plate can be a PTFE film, preferably, the material of the isolation plate can be a PTFE film of Teflon.

[0072] The flue gas inlet of the absorption part is used to communicate with the flue gas containing carbon dioxide, and the absorbent inlet of the absorption part is used 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.

[0073] It should be noted that the specific structural features of the absorption device are not specifically limited in this embodiment and can be selected according to actual needs.

[0074] like Figure 2 As shown, another aspect of the present invention provides an electrochemical carbon dioxide capture method S100 coupled with high-purity hydrogen preparation, using the electrochemical carbon dioxide capture system coupled with high-purity hydrogen preparation as described above. The specific structure of the electrochemical carbon dioxide capture system coupled with high-purity hydrogen preparation has been described in detail above and will not be repeated here. The method S100 includes:

[0075] S110, transporting flue gas containing carbon dioxide to the absorption device, and absorbing carbon dioxide in the flue gas through the absorbent in the absorption device to obtain absorption liquid and purified gas.

[0076] Specifically, the ammonia solution absorbent in the absorption device 1 may contain a supporting electrolyte, which may be potassium chloride, sodium chloride, sodium sulfate, etc. In addition, some additives may be added to the absorbent in the absorption unit 1, such as tetraethylammonium chloride, tetrapropylammonium chloride, etc. surfactants. The absorption liquid is a liquid with a high carbon dioxide load obtained after the absorbent absorbs carbon dioxide, and the purified gas refers to the gas obtained after the flue gas is freed of carbon dioxide.

[0077] S120, transporting the absorption liquid to the anode chamber of the electrolytic hydrogen production device, and obtaining a gas-liquid mixture containing carbon dioxide under the action of the oxygen evolution electrode.

[0078] 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 of the anode chamber 21, and the oxygen evolution electrode reacts: 4OH - -4e - =O 2 ↑+2H2O, the hydrogen evolution electrode reacts: 4H2O+4e - =2H2↑+4OH - OH near the oxygen evolution electrode - As the concentration decreases, the acidity of the reaction liquid increases, CO2 is released, and a gas-liquid mixture containing carbon dioxide is obtained.

[0079] S130. Performing gas-liquid separation on the gas-liquid mixture containing carbon dioxide through the first gas-liquid separation device to obtain carbon dioxide gas and a first separation liquid, discharging the separated carbon dioxide and conveying the separation liquid to the intermediate chamber, obtaining an absorbent through ion exchange of the anion exchange membrane in the separation liquid in the intermediate chamber to achieve regeneration of the absorbent, and conveying the regenerated absorbent to the absorption device to continue absorbing carbon dioxide.

[0080] Specifically, 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 the first separated liquid. The first separated liquid enters the intermediate chamber 22 through the first separated liquid pipeline 53, and the hydrogen evolution cathode produces OH - Then, it enters the intermediate chamber 23 through the anion exchange membrane 24, and the alkalinity of the solution in the intermediate chamber 23 is enhanced to obtain an absorbent, thereby realizing the regeneration of the absorbent. The regenerated absorbent enters the absorption device 1 through the absorbent pipeline 54 from the intermediate chamber 22, and continues to provide absorbent to the absorption device 1, thereby continuing to realize the absorption of carbon dioxide.

[0081] S140, transporting the hydrogen-containing solution in the cathode chamber to the first gas-liquid separation device to obtain hydrogen and a second separation liquid, discharging the separated hydrogen through a first exhaust pipe and transporting the second separation liquid to the inlet of the cathode chamber to achieve independent separation and discharge of hydrogen.

[0082] Among them, in this embodiment, the second gas-liquid separation device 4 is a gas-liquid separator, and the gas-liquid separator 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 purifies and separates the hydrogen-containing solution to obtain hydrogen and a second separated liquid, wherein the obtained hydrogen is discharged through the first exhaust pipeline 57 for the next step of hydrogen collection. The obtained second separated liquid enters the cathode chamber 23 again through the second gas-liquid separation device 4, and hydrogen is prepared and separated and purified again to achieve independent separation and discharge of hydrogen.

[0083] The electrochemical carbon dioxide capture method coupled with high-purity hydrogen preparation of the present invention couples the absorption and capture process of carbon dioxide in flue gas with the process of hydrogen production by electrolysis, and purifies and collects hydrogen while capturing carbon dioxide, thereby improving energy efficiency, saving energy consumption, and saving operating costs, and complying with the concept of green environmental protection; the purification and collection of hydrogen is carried out separately in the cathode chamber and does not participate in the carbon dioxide capture system, which can avoid the risk of explosion caused by hydrogen mixing with absorption liquid and then entering the anode chamber and mixing with oxygen, thereby increasing the safety of carbon dioxide capture and hydrogen production processes.

[0084] It is to be understood that the above embodiments are merely exemplary embodiments used to illustrate the principles of the present invention, but the present invention is not limited thereto. For those of ordinary skill in the art, various modifications and improvements can be made without departing from the spirit and essence of the present invention, and these modifications and improvements are also considered to be within the scope of protection of the present invention.

Claims

1. An electrochemical carbon dioxide capture system coupled with high-purity hydrogen production, characterized in that: It includes 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 separated by an anion exchange membrane, wherein the anode chamber adopts an oxygen evolution electrode, and the cathode chamber adopts a hydrogen evolution electrode; The first inlet of the absorption device is used to communicate with the flue gas containing carbon dioxide, the first outlet of the absorption device is connected to the inlet of the anode chamber through an absorption liquid pipeline, the outlet of the anode chamber is connected to the inlet of the first gas-liquid separation device through a gas-liquid mixture pipeline, the first outlet of the first gas-liquid separation device is connected to the inlet of the intermediate chamber through a first separation liquid pipeline, and the outlet of the intermediate chamber is connected to the second inlet of the absorption device through an absorbent pipeline, so as to realize the regeneration cycle of the absorbent; The inlet of the second gas-liquid separation device is connected to the outlet of the cathode chamber through a hydrogen-containing solution pipeline, the first outlet of the second gas-liquid separation device is connected to the inlet of the cathode chamber through a second separation liquid pipeline, and the second outlet of the second gas-liquid separation device is connected to the first exhaust pipeline, so as to realize independent separation and discharge of hydrogen; The second outlet of the first gas-liquid separation device is connected to the second exhaust pipe to discharge the separated carbon dioxide, and the second outlet of the absorption device is connected to the purified gas pipeline to discharge the purified gas.

2. The system according to claim 1, characterized in that 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 according to claim 1, characterized in that The first gas-liquid separation device includes a flash tank and a condenser; The gas-liquid mixture inlet of the flash tank is connected to the outlet of the anode chamber, the gas inlet to be condensed of the condenser is connected to the gas outlet to be condensed of the flash tank, the condensate inlet of the flash tank is connected to the condensate outlet of the condenser, and the inlet of the intermediate chamber is connected to the separated liquid outlet of the flash tank; The top of the condenser is connected to the second exhaust pipe to discharge the separated carbon dioxide.

4. The system according to any one of claims 1 to 3, characterized in that: Also includes a shower device; The first inlet of the elution device is connected to the second outlet of the absorption device through the purified gas pipeline; The second inlet of the rinsing device is used to be connected to the rinsing water source; The first outlet of the rinsing device is connected to the gas exhaust pipeline.

5. The system according to claim 4, characterized in that It also includes a desulfurization unit; The first inlet of the desulfurization device is used to communicate with the flue gas containing carbon dioxide, and the first outlet of the desulfurization device is connected to the first inlet of the absorption device; The second inlet of the desulfurization device is connected to the second outlet of the elution device; The reflux outlet of the desulfurization device is communicated with the reflux inlet of the elution device.

6. The system according to claim 5, characterized in that Also includes a recovery device; The inlet of the recovery device is connected to the reflux outlet of the desulfurization device, so that when the desulfurization liquid in the desulfurization device reaches saturation, the liquid material in the desulfurization device is transported to the recovery device for treatment.

7. The system according to claim 5, characterized in that Also included is a first heat exchange device; The first heat exchange device is respectively connected to the elution device and the desulfurization device, and is used for heat exchange between the elution device and the desulfurization device.

8. The system according to any one of claims 1 to 3, characterized in that: Also comprising a second heat exchange device; The second heat exchange device is respectively connected to the absorption device and the electrolysis device, and is used for heat exchange between the absorption device and the electrolysis device.

9. The system according to claim 8, characterized in that 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. An electrochemical carbon dioxide capture method coupled with high-purity hydrogen production, characterized in that: The electrochemical carbon dioxide capture system coupled with high-purity hydrogen production according to any one of claims 1 to 9, the method comprising: The flue gas containing carbon dioxide is transported to the absorption device, and the carbon dioxide in the flue gas is absorbed by the absorbent in the absorption device to obtain an absorption liquid and a purified gas; The absorption liquid is transported 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; The gas-liquid mixture containing carbon dioxide is subjected to gas-liquid separation by the first gas-liquid separation device to obtain carbon dioxide gas and a first separation liquid, the separated carbon dioxide is discharged and the separation liquid is transported to the intermediate chamber, the separation liquid in the intermediate chamber is subjected to ion exchange of the anion exchange membrane to obtain an absorbent, the absorbent is regenerated, and the regenerated absorbent is transported to the absorption device to continue absorbing carbon dioxide; The hydrogen-containing solution in the cathode chamber is transported to the first gas-liquid separation device to obtain hydrogen and a second separation liquid. The separated hydrogen is discharged through a first exhaust pipe and the second separation liquid is transported to the inlet of the cathode chamber to achieve independent separation and discharge of hydrogen.

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