Electrochemical carbon dioxide trapping system and method coupled with metal refining

Abstract

The invention provides an electrochemical carbon dioxide trapping system and method coupled with metal refining. According to the system, carbon dioxide is absorbed in an absorption unit through an absorbent; a crude copper metal plate in coordination combination with ammonia is adopted as an electrode of an anode chamber, absorption liquid is desorbed under the action of a crude copper anode, elements, more active than metal copper, in the crude copper anode in the anode chamber are dissolved in the absorption liquid, and copper ions can be released into the carbon dioxide loaded absorption liquid in an electrochemical dissolution mode; carbon dioxide is desorbed in a mode of coordination combination with ammonia, and a gas mixture containing the copper / ammonia coordination compound and carbon dioxide is obtained; separating the gas-liquid mixture through a gas-liquid separation unit to obtain carbon dioxide gas and a separation liquid; the separation liquid is subjected to electrodeposition under the action of a refined copper cathode in a cathode chamber, refined copper and an absorbent are obtained, and regeneration of the absorbent is achieved; finally, the absorbent enters the absorption unit again to provide the absorbent, and cyclic utilization of the absorbent is achieved.

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 metal refining. 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 application. In particular, the steam heat consumed by absorbent regeneration accounts for a large proportion of the total system energy consumption, 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] In view of the above problems, it is necessary to propose an electrochemical carbon dioxide capture system and method coupled with metal refining that is reasonably designed and effectively solves the above problems. Summary of the invention

[0005] The present invention aims to solve at least one of the technical problems existing in the prior art and provide an electrochemical carbon dioxide capture system and method coupled with metal refining.

[0006] One aspect of the present invention provides an electrochemical carbon dioxide capture system coupled to metal refining, comprising an absorption unit, an electrodesorption unit and a gas-liquid separation unit;

[0007] The absorption unit is provided with an absorbent, and the electrolysis absorption unit comprises an anode chamber and a cathode chamber which are separated and arranged, wherein the anode chamber is provided with a crude copper anode, and the cathode chamber is provided with a refined copper cathode;

[0008] The first inlet of the absorption unit is used to communicate with the flue gas containing carbon dioxide to absorb the carbon dioxide in the flue gas to obtain absorption liquid and purified gas;

[0009] The first outlet of the absorption unit is connected to the inlet of the anode chamber through an absorption liquid pipeline, so that the absorption liquid is desorbed under the action of the crude copper anode, wherein elements in the crude copper anode that are more active than metallic copper are dissolved into the absorption liquid to obtain a gas mixture containing a copper / ammonia coordination compound and carbon dioxide;

[0010] The second outlet of the absorption unit is connected to the purified gas pipeline to discharge the purified gas;

[0011] The outlet of the anode chamber is connected to the inlet of the gas-liquid separation unit through a gas-liquid mixture pipeline, so that the gas-liquid mixture is separated in the gas-liquid separation unit to obtain carbon dioxide gas and separation liquid, wherein the carbon dioxide gas is discharged through the first outlet of the gas-liquid separation unit;

[0012] The second outlet of the gas-liquid separation unit is connected to the inlet of the cathode chamber through a separation liquid pipeline, so that the copper ions in the separation liquid are electro-deposited under the action of the refined copper cathode to obtain refined copper and absorbent;

[0013] The outlet of the cathode chamber is connected to the second inlet of the absorption unit through an absorbent pipeline to provide absorbent into the absorption unit.

[0014] Optionally, the absorption unit includes an absorption part, a condensation part, and an isolation plate for isolating the absorption part from the condensation part;

[0015] The absorption part is located at the bottom of the absorption unit, and the condensation part is located at the top of the absorption unit; wherein the isolation plate allows gas to pass through and blocks liquid substances from passing through;

[0016] 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 cathode chamber;

[0017] 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.

[0018] Optionally, a rinsing unit is also included;

[0019] The first inlet of the elution unit is connected to the second outlet of the absorption unit through the purified gas pipeline;

[0020] The second inlet of the rinsing unit is used to be connected to the rinsing water source;

[0021] The first outlet of the elution unit is connected to the gas exhaust pipeline.

[0022] Optionally, a desulfurization unit is also included;

[0023] The first inlet of the desulfurization unit is used to communicate with the flue gas containing carbon dioxide, and the first outlet of the desulfurization unit is connected to the first inlet of the absorption unit;

[0024] The second inlet of the desulfurization unit is connected to the second outlet of the elution unit;

[0025] The reflux outlet of the desulfurization unit is communicated with the reflux inlet of the elution unit.

[0026] Optionally, a recovery unit is also included;

[0027] The inlet of the recovery unit is connected to the reflux outlet of the desulfurization unit, so that when the desulfurization liquid in the desulfurization unit reaches saturation, the liquid material in the desulfurization unit is transported to the recovery unit for treatment.

[0028] Optionally, it also includes a first heat exchange unit;

[0029] The first heat exchange unit is respectively connected to the elution unit and the desulfurization unit, and is used for heat exchange between the elution unit and the desulfurization unit.

[0030] Optionally, the gas-liquid separation unit includes a flash tank and a condenser;

[0031] 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 cathode chamber is connected to the separated liquid outlet of the flash tank;

[0032] The top of the condenser also includes a carbon dioxide outlet for discharging the separated carbon dioxide.

[0033] Optionally, it also includes a second heat exchange unit;

[0034] The second heat exchange unit is respectively connected to the absorption unit and the electrolysis unit, and is used for heat exchange between the absorption unit and the electrolysis unit.

[0035] Optionally, the second heat exchange unit includes a cold end inlet, a cold end outlet, a hot end inlet and a hot end outlet;

[0036] The cold end inlet of the second heat exchange unit is connected to the second outlet of the absorption unit, the hot end outlet of the second heat exchange unit is connected to the inlet of the anode chamber, the hot end inlet of the second heat exchange unit is connected to the outlet of the cathode chamber, and the cold end outlet of the second heat exchange unit is connected to the second inlet of the absorption unit.

[0037] Another aspect of the present disclosure provides a method for electrochemical carbon dioxide capture coupled with metal refining, using the electrochemical carbon dioxide capture system coupled with metal refining as described above, the method comprising:

[0038] Step 1, transporting flue gas containing carbon dioxide to the absorption unit, and absorbing carbon dioxide in the flue gas through the absorbent in the absorption unit to obtain absorption liquid and purified gas;

[0039] Step 2, transporting the absorption liquid to the anode chamber of the electrolysis unit, desorbing the absorption liquid under the action of the crude copper anode, wherein the elements in the crude copper anode that are more active than metallic copper are dissolved into the absorption liquid to obtain a gas mixture containing a copper / ammonia coordination compound and carbon dioxide;

[0040] Step 3, performing gas-liquid separation on the gas-liquid mixture through the gas-liquid separation unit to obtain carbon dioxide gas and separation liquid;

[0041] Step 4, transporting the separated liquid to the cathode chamber of the electrolytic desorption unit, so that the copper ions in the separated liquid are electro-deposited under the action of the refined copper cathode to obtain refined copper and absorbent;

[0042] Step five: transporting the absorbent in the cathode chamber to the absorption unit to continue absorbing carbon dioxide in the flue gas.

[0043] The present invention discloses an electrochemical carbon dioxide capture system and method coupled with metal refining. The system of the present invention couples the metal refining process with the carbon dioxide collection process, and has higher energy efficiency, lower energy consumption and lower operating costs. The carbon dioxide-rich liquid enters the anode chamber and the cathode chamber in sequence, thereby improving the regeneration efficiency of the carbon dioxide-rich liquid. The absorbent produced by the electrodeposition in the cathode chamber enters the absorption unit again to absorb carbon dioxide, thereby realizing the recycling of the absorbent and the recovery of the deposited metal, having low energy consumption requirements and low operating costs, and improving the circulation efficiency of the entire system. The carbon dioxide capture rate / decarbonization rate is high, and the purity of the discharged carbon dioxide product is high. While absorbing carbon dioxide, the refining of metallic copper can also be achieved to obtain refined copper with higher purity, which is in line with the concept of green environmental protection. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 This is a schematic structural diagram of an electrochemical carbon dioxide capture system coupled with metal refining according to an embodiment of the present invention;

[0045] Figure 2 It is a structural schematic diagram of an absorption unit according to another embodiment of the present invention;

[0046] Figure 3 It is a schematic flow chart of a method for capturing carbon dioxide coupled with metal refining in another embodiment of the present invention. DETAILED DESCRIPTION

[0047] 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.

[0048] like Figure 1 As shown, one aspect of the present invention provides an electrochemical carbon dioxide capture system coupled with metal refining, comprising an absorption unit 1 , an electrodesorption unit 2 and a gas-liquid separation unit 3 .

[0049] An absorbent is arranged in the absorption unit, and the electrodesorption unit 2 includes an anode chamber 21 and a cathode chamber 22 which are separated, wherein a crude copper anode is arranged in the anode chamber 21, and a refined copper cathode is arranged in the cathode chamber 22. That is to say, the electrode in the anode chamber 21 is a crude copper metal plate, and the electrode in the cathode chamber 22 is a refined copper metal plate. The anode chamber 21 and the cathode chamber 22 are separated by an anion exchange membrane 23. It should be noted that in addition to the crude copper and refined copper as electrodes in this embodiment, crude nickel and refined nickel can also be used as electrodes, as long as the metal refining process can be realized in the process of carbon dioxide capture, and the type of electrodes in the anode chamber and the cathode chamber can be selected according to actual needs.

[0050] 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.

[0051] A crude copper anode is arranged in the anode chamber 21, and a refined copper cathode is arranged in the cathode chamber 22, wherein there are relatively high impurities in the crude copper, such as lead, antimony, etc. During the electrolysis process, these impurity metals will dissolve into ions together with copper. Since the activity of metals such as gold, platinum, and silver is not as good as that of copper, they will directly precipitate under the anode to form anode mud, thereby realizing the separation of impurities and copper and improving the purity of copper. Crude copper also contains a large amount of chemical substances such as copper oxide. In the electrolyte, these copper oxides will be reduced to pure copper, increasing the amount of reduction reaction in the refining process, thereby improving the refining effect of copper. Through the above process, the crude copper on the anode is gradually dissolved, and the impurities are removed or precipitated, and finally the copper ions with higher purity are obtained, which can be formed into refined copper with higher purity through electrodeposition at the cathode, providing high-quality raw materials for the refined copper of the cathode. While absorbing carbon dioxide, the system can also realize the refining of metallic copper, and obtain refined copper with higher purity, which conforms to the concept of green environmental protection.

[0052] The first inlet of the absorption unit 1 is used to communicate with the flue gas containing carbon dioxide to absorb the carbon dioxide in the flue gas to obtain absorption liquid and purified gas.

[0053] Specifically, flue gas containing carbon dioxide enters the absorption unit 1 through the first inlet of the absorption unit 1, and the absorbent in the absorption unit 1 absorbs carbon dioxide to obtain absorption liquid and 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.

[0054] The first outlet of the absorption unit 1 is connected to the inlet of the anode chamber 21 in the electrolytic desorption unit 2 through the absorption liquid pipeline 41, so that the absorption liquid is transported to the anode chamber 21 through the absorption liquid pipeline 41. Under the action of the crude copper anode, the absorption liquid is desorbed, wherein the elements in the crude copper anode that are more active than metallic copper are dissolved into the absorption liquid, and a gas mixture containing a copper / ammonia coordination compound and carbon dioxide is obtained. Among them, the liquid component in the gas-liquid mixture is low in carbon dioxide load and high in metal load, mainly because most of the carbon dioxide is in the form of gas.

[0055] The electrolysis unit 2 utilizes the electrochemical principle and adopts an electrochemical cycle with high energy utilization rate. By supplying power to the electrolysis unit 2, the desorption of carbon dioxide and the regeneration of ammonia can be achieved. The desorption of carbon dioxide is specifically as follows: since the electrode of the anode chamber 21 contains copper elements that can coordinate with ammonia, the electrode of the anode chamber 21 can produce corresponding metal copper ions. Through the coordination of the metal copper ions and ammonia, the carbon dioxide in the absorption liquid can be desorbed, thereby reducing energy consumption while ensuring the desorption of carbon dioxide. At the same time, during the electrolysis process, elements in the crude copper anode that are more active than metallic copper dissolve into the absorption liquid, realizing the separation of impurities in the crude copper anode, and obtaining copper ions with higher purity.

[0056] The second outlet of the absorption unit 1 is connected to the purified gas pipeline 42 to discharge the purified gas. In other words, the purified gas obtained after removing carbon dioxide from the flue gas can be discharged through the purified gas pipeline 42.

[0057] The outlet of the anode chamber 21 is connected to the inlet of the gas-liquid separation unit 3 through the gas-liquid mixture pipeline 43, and the gas-liquid mixture generated by the anode chamber 21 is transported to the gas-liquid separation unit 3 through the gas-liquid mixture pipeline 43. The gas-liquid mixture is separated by the gas-liquid separation unit 3 to obtain carbon dioxide gas and separation liquid. Since ammonia has been coordinated with the metal copper ions, gaseous carbon dioxide can be easily separated from the gas-liquid mixed solution. The separated carbon dioxide gas is discharged through the first outlet of the gas-liquid separation unit 3.

[0058] The second outlet of the gas-liquid separation unit 3 is connected to the inlet of the cathode chamber 22 through the separation liquid pipeline 44, and the separation liquid is transported to the cathode chamber 22 of the electrolysis desorption unit 2. The copper ions in the separation liquid are electro-deposited under the action of the refined copper cathode to obtain refined copper and absorbent, wherein the absorbent in the cathode chamber 22 has a low carbon dioxide load and a low metallic copper load. Through the electro-deposition of the separation liquid in the cathode chamber 22, the regeneration of the absorbent and the recovery of refined copper are achieved, which saves resources, conforms to the concept of green environmental protection, and improves the economy of the entire system.

[0059] The outlet of the cathode chamber 22 is connected to the second inlet of the absorption unit 1 through the absorbent pipe 45, and the absorbent produced in the cathode chamber 22 is transported to the absorption unit 1 through the absorbent pipe 45 to provide absorbent to the absorption unit 1, continue to absorb carbon dioxide in the flue gas, realize the recycling of the absorbent, and further realize the complete carbon dioxide capture cycle.

[0060] Specifically, in the whole system of the present invention, carbon dioxide is absorbed in the absorption unit by the absorbent; by using a copper metal plate coordinated with ammonia as the electrode of the anode chamber, the absorption liquid is desorbed under the action of the copper anode, wherein in the anode chamber, elements in the copper anode that are more active than metallic copper are dissolved into the absorption liquid, and copper ions can be released into the carbon dioxide-loaded absorption liquid in the anode chamber by electrochemical dissolution, and carbon dioxide is desorbed by coordination with ammonia to obtain a gas mixture containing a copper / ammonia coordination compound and carbon dioxide; the gas-liquid mixture is separated by a gas-liquid separation unit to obtain carbon dioxide gas and a separation liquid; the separation liquid undergoes electrodeposition under the action of a refined copper cathode in the cathode chamber, and copper ions are deposited on the cathode to obtain refined copper and absorbent, thereby realizing ammonia regeneration; finally, the absorbent enters the absorption unit again to provide the absorption unit with absorbent, thereby ensuring the supply of absorbent in the subsequent carbon dioxide capture process in the absorption unit.

[0061] An electrochemical carbon dioxide capture system coupled with metal refining according to an embodiment of the present disclosure couples the metal refining process with the carbon dioxide collection process, thereby achieving higher energy efficiency, lower energy consumption, and lower operating costs; the carbon dioxide-rich liquid enters the anode chamber and the cathode chamber in sequence, thereby improving the regeneration efficiency of the carbon dioxide-rich liquid; the absorbent produced by the electrodeposition in the cathode chamber enters the absorption unit again to absorb carbon dioxide, thereby achieving the recycling of the absorbent and the recovery of the deposited metal, having low energy consumption requirements and low operating costs, and improving the circulation efficiency of the entire system; the carbon dioxide capture rate / decarbonization rate is high, and the purity of the discharged carbon dioxide product is high; while absorbing carbon dioxide, the refining of metallic copper can also be achieved to obtain refined copper with higher purity, which is in line with the concept of green environmental protection.

[0062] For example, Figure 2As shown, the absorption unit 1 includes an absorption part 11 , a condensation part 12 , and an isolation plate 13 for isolating the absorption part 11 from the condensation part 12 .

[0063] The absorption part 11 is located at the bottom of the absorption unit 1, and the condensation part 12 is located at the top of the absorption unit 1. The isolation plate 12 allows gas to pass through and blocks liquid substances from passing through. The material of the isolation plate 12 can be a PTFE film, preferably, the material of the isolation plate 12 can be a PTFE film of Teflon.

[0064] The flue gas inlet of the absorption part 11 is used to communicate with the flue gas containing carbon dioxide, and the absorbent inlet of the absorption part 11 is used to communicate with the outlet of the cathode chamber 22.

[0065] The absorption liquid outlet of the condensation section 12 is connected to the absorption liquid pipeline 41 , and the gas outlet of the condensation section 12 is connected to the purified gas pipeline 42 .

[0066] Specifically, the absorption part 11 and the condensation part 12 are connected through a conveying pipeline, one end of the conveying pipeline is connected to the bottom of the absorption part 11, and the other end of the conveying pipeline is connected to the upper part of the condensation part 12. A cooling component is installed on the conveying pipeline. Specifically, the connection point between the absorption part 11 and the pipeline can be located at the bottom of the absorption part 11, and the connection point between the condensation part 12 and the pipeline can be located at the upper part of the condensation part 12, and lower than the height position of the purified gas.

[0067] Specifically, flue gas containing carbon dioxide enters the absorption part 11 through the flue gas inlet, and the absorbent enters the absorption part 11 through the absorbent inlet, and absorbs carbon dioxide in the absorption part 11. After the absorbent absorbs carbon dioxide, it is transported to the condensation part 12 through the pipeline, and the purified gas obtained after absorption is discharged from the gas outlet, and the absorption liquid obtained after absorbing carbon dioxide is discharged to the anode chamber 21. It should be noted that since a cooling component is installed on the pipeline, ammonia can be present in the solution, thereby avoiding the volatilization of ammonia and ensuring the recycling of ammonia.

[0068] Exemplarily, the electrochemical carbon dioxide capture system coupled with metal refining of the present invention further includes a leaching unit 5. The first inlet of the leaching unit 5 is connected to the second outlet of the absorption unit 1 through the purified gas pipeline 42. The second inlet of the leaching unit 5 is used to be connected to the leaching water source. The first outlet of the leaching unit 5 is connected to the gas exhaust pipeline 46.

[0069] Specifically, the purified gas generated in the absorption unit 1 will contain residual ammonia, and the purified gas containing ammonia is transmitted to the elution unit 5 through the purified gas pipeline 42. The elution water source enters the elution unit 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, and the absorbent and the gas to be discharged are obtained. The gas to be discharged is discharged through the gas discharge pipeline 46.

[0070] For example, Figure 1 As shown, the electrochemical carbon dioxide capture system coupled with metal refining of the present invention further comprises a desulfurization unit 6. The first inlet of the desulfurization unit 6 is used to communicate with the flue gas containing carbon dioxide, and the flue gas containing carbon dioxide first enters the desulfurization unit 6 for pretreatment of flue gas desulfurization to obtain a desulfurized liquid.

[0071] The first outlet of the desulfurization unit 6 is connected to the first inlet of the absorption unit 1. The flue gas after desulfurization treatment enters the absorption unit 1 to absorb and capture carbon dioxide.

[0072] The second inlet of the desulfurization unit 6 is connected to the second outlet of the elution unit 5. The ammonia separated in the elution unit 5 is transported from the elution unit 5 to the desulfurization unit 6 in the form of an ammonia-containing eluent.

[0073] The reflux outlet of the desulfurization unit 6 is connected to the reflux inlet of the elution unit 5. The height of the reflux inlet is lower than the height of the second inlet.

[0074] 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 unit 6 to the elution unit 5 to elute the purified gas, and is transported from the elution unit 5 to the desulfurization device 6 along with the separated ammonia-containing eluent, forming a circulation loop.

[0075] 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.

[0076] For example, Figure 1 As shown, the electrochemical carbon dioxide capture system coupled with metal refining of the present invention also includes a recovery unit 7, the inlet of the recovery unit 7 is connected to the reflux outlet of the desulfurization unit 6, so that when the desulfurization liquid in the desulfurization unit reaches saturation, the liquid material in the desulfurization unit 6 is transported to the recovery unit 7 for treatment.

[0077] Specifically, when the desulfurized liquid reaches saturation, the liquid substance in the desulfurization unit 6 can be transported to the recovery unit 7 for processing to obtain the utilization of sulfur dioxide, such as ammonium sulfate fertilizer product. The desulfurized liquid can be recycled and reused through the recovery unit 7, saving resources.

[0078] For example, Figure 1 As shown, the electrochemical carbon dioxide capture system coupled with metal refining of the present invention further includes a first heat exchange unit 8, which is respectively connected to the elution unit 5 and the desulfurization unit 6 and is used for heat exchange between the elution unit 5 and the desulfurization unit 6.

[0079] Specifically, the ammonia-containing eluent and the desulfurization liquid can be heat exchanged through the first heat exchange unit 8, and the heat exchange between the ammonia-containing eluent and the desulfurization liquid is performed through the first heat exchange unit 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.

[0080] In this embodiment, the heat utilization rate of the entire system is improved by the first heat exchange unit, thereby saving energy consumption.

[0081] For example, Figure 1 As shown, the gas-liquid separation unit 3 includes a flash tank 31 and a condenser 32 .

[0082] 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 cathode chamber 22 is connected to the separated liquid outlet of the flash tank 31. The top of the condenser 32 also includes a carbon dioxide outlet for discharging the separated carbon dioxide.

[0083] The separation liquid is a mixture of the initial separation 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 .

[0084] 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.

[0085] For example, Figure 1As shown, the electrochemical carbon dioxide capture system coupled with metal refining of the present invention further includes a second heat exchange unit 9, which is respectively connected to the absorption unit 1 and the electrolysis unit 2, and is used for heat exchange between the absorption unit 1 and the electrolysis unit 2.

[0086] Specifically, the second heat exchange unit 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 unit 9 is connected to the second outlet of the absorption unit 1, the hot end outlet of the second heat exchange unit 9 is connected to the inlet of the anode chamber 21, the hot end inlet of the second heat exchange unit 9 is connected to the outlet of the cathode chamber 21, and the cold end outlet of the second heat exchange unit 9 is connected to the second inlet of the absorption unit 1.

[0087] In this embodiment, the absorbent and the absorption liquid exchange heat only through the second heat exchange unit 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 unit 9. The conveying channel between the cold end outlet of the second heat exchange unit 9 and the absorbent inlet of the absorption unit 1 is used to convey the absorbent to the absorption unit 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 unit 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.

[0088] like Figure 3 As shown, another aspect of the present invention provides an electrochemical carbon dioxide capture method coupled with metal refining, using the electrochemical carbon dioxide capture system coupled with metal refining as described above. The specific structural features of the electrochemical carbon dioxide capture system coupled with metal refining have been described in detail above and will not be repeated here. The method S100 includes:

[0089] Step 1: transport the flue gas containing carbon dioxide to an absorption unit, and absorb the carbon dioxide in the flue gas through the absorbent in the absorption unit to obtain an absorption liquid and a purified gas.

[0090] Specifically, the ammonia solution absorbent in the absorption unit 1 may contain a supporting electrolyte, which may be potassium chloride, sodium chloride, sodium sulfate and the like; in addition, some additives may be added to the absorbent in the absorption unit 1, such as quaternary ammonium salts such as tetraethylammonium chloride and tetrapropylammonium chloride, and other surfactants.

[0091] 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 carbon dioxide is removed from the flue gas.

[0092] Step 2: transport the absorption liquid to the anode chamber of the electrolytic desorption unit, and desorb the absorption liquid under the action of the crude copper anode, wherein the elements in the crude copper anode that are more active than metallic copper are dissolved into the absorption liquid to obtain a gas mixture containing a copper / ammonia coordination compound and carbon dioxide.

[0093] Among them, the liquid component in the gas-liquid mixture is low carbon dioxide load and high metal load, mainly because most of the carbon dioxide is in the form of gas. Among them, the desorption of carbon dioxide is specifically: since the electrode of the anode chamber 21 contains copper elements that can coordinate with ammonia, the electrode of the anode chamber 21 can produce corresponding metal copper ions, and the carbon dioxide in the absorption liquid can be desorbed through the coordination of metal copper ions and ammonia, thereby reducing energy consumption while ensuring the desorption of carbon dioxide. At the same time, in the process of electrolysis, elements in the crude copper anode that are more active than metallic copper dissolve into the absorption liquid, realizing the separation of impurities in the crude copper anode, and obtaining copper ions with higher purity.

[0094] Step three, performing gas-liquid separation on the gas-liquid mixture through a gas-liquid separation unit to obtain carbon dioxide gas and separation liquid.

[0095] Specifically, in this embodiment, the gas-liquid separation process specifically includes: flashing and condensing the gas-liquid mixture in sequence; wherein, after flashing, an initial separation liquid and a gas to be condensed are obtained, and after condensation, carbon dioxide gas and a condensate are obtained.

[0096] Step 4: transport the separated liquid to the cathode chamber of the electrolytic desorption unit, so that the copper ions in the separated liquid are electro-deposited under the action of the refined copper cathode to obtain refined copper and absorbent.

[0097] Specifically, the copper ions in the separation liquid are electro-deposited under the action of the refined copper cathode to obtain refined copper and absorbent, wherein the absorbent in the cathode chamber 22 has a low carbon dioxide load and a low metallic copper load. Through the electro-deposition of the separation liquid in the cathode chamber 22, ammonia regeneration and refined copper recovery are achieved, which saves resources and conforms to the concept of green environmental protection.

[0098] Step five, transporting the absorbent in the cathode chamber to the absorption unit to continue absorbing the carbon dioxide in the flue gas.

[0099] Specifically, the absorbent produced in the cathode chamber 22 is transported to the absorption unit 1 through the absorbent pipeline 45 to provide the absorbent to the absorption unit 1, continue to absorb the carbon dioxide in the flue gas, realize the recycling of ammonia, and further realize the complete carbon dioxide capture cycle.

[0100] The electrochemical carbon dioxide capture method coupled with metal refining of the present invention adopts an electric cycle carbon capture mode, and has higher energy efficiency, lower energy consumption and lower operating cost in the process of absorbing and capturing carbon dioxide in flue gas; the carbon dioxide rich liquid enters the anode chamber and the cathode chamber in sequence, thereby improving the regeneration efficiency of the carbon dioxide rich liquid; the absorbent produced by the electrodeposition effect of the cathode chamber enters the absorption unit again to absorb carbon dioxide, thereby realizing the recycling of ammonia and the recovery of deposited metals, having low energy consumption requirements and low operating costs, and improving the cycle efficiency of the entire system; the carbon dioxide capture rate / decarbonization rate is high, and the purity of the discharged carbon dioxide product is high; while absorbing carbon dioxide, the refining of metallic copper can also be achieved to obtain refined copper with higher purity, which is in line with the concept of green environmental protection.

[0101] 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 to metal refining, characterized in that: It includes an absorption unit, an electrodesorption unit and a gas-liquid separation unit; The absorption unit is provided with an absorbent, and the electrolysis absorption unit comprises an anode chamber and a cathode chamber which are separated and arranged, wherein the anode chamber is provided with a crude copper anode, and the cathode chamber is provided with a refined copper cathode; The first inlet of the absorption unit is used to communicate with the flue gas containing carbon dioxide to absorb the carbon dioxide in the flue gas to obtain absorption liquid and purified gas; The first outlet of the absorption unit is connected to the inlet of the anode chamber through an absorption liquid pipeline, so that the absorption liquid is desorbed under the action of the crude copper anode, wherein elements in the crude copper anode that are more active than metallic copper are dissolved into the absorption liquid to obtain a gas mixture containing a copper / ammonia coordination compound and carbon dioxide; The second outlet of the absorption unit is connected to the purified gas pipeline to discharge the purified gas; The outlet of the anode chamber is connected to the inlet of the gas-liquid separation unit through a gas-liquid mixture pipeline, so that the gas-liquid mixture is separated in the gas-liquid separation unit to obtain carbon dioxide gas and separation liquid, wherein the carbon dioxide gas is discharged through the first outlet of the gas-liquid separation unit; The second outlet of the gas-liquid separation unit is connected to the inlet of the cathode chamber through a separation liquid pipeline, so that the copper ions in the separation liquid are electro-deposited under the action of the refined copper cathode to obtain refined copper and absorbent; The outlet of the cathode chamber is connected to the second inlet of the absorption unit through an absorbent pipeline to provide absorbent into the absorption unit.

2. The system according to claim 1, characterized in that The absorption unit includes an absorption part, a condensation part, and an isolation plate that isolates the absorption part from the condensation part; The absorption part is located at the bottom of the absorption unit, and the condensation part is located at the top of the absorption unit; wherein the isolation plate allows gas to pass through and blocks liquid substances from passing through; 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 cathode 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.

3. The system according to claim 1, characterized in that Also includes a rinsing unit; The first inlet of the elution unit is connected to the second outlet of the absorption unit through the purified gas pipeline; The second inlet of the rinsing unit is used to be connected to the rinsing water source; The first outlet of the elution unit is connected to the gas exhaust pipeline.

4. The system according to claim 3, characterized in that It also includes a desulfurization unit; The first inlet of the desulfurization unit is used to communicate with the flue gas containing carbon dioxide, and the first outlet of the desulfurization unit is connected to the first inlet of the absorption unit; The second inlet of the desulfurization unit is connected to the second outlet of the elution unit; The reflux outlet of the desulfurization unit is communicated with the reflux inlet of the elution unit.

5. The system according to claim 4, characterized in that Also includes a recycling unit; The inlet of the recovery unit is connected to the reflux outlet of the desulfurization unit, so that when the desulfurization liquid in the desulfurization unit reaches saturation, the liquid material in the desulfurization unit is transported to the recovery unit for treatment.

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

7. The system according to any one of claims 1 to 5, characterized in that: The gas-liquid separation unit comprises 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 cathode chamber is connected to the separated liquid outlet of the flash tank; The top of the condenser also includes a carbon dioxide outlet for discharging the separated carbon dioxide.

8. The system according to any one of claims 1 to 5, characterized in that: Also comprising a second heat exchange unit; The second heat exchange unit is respectively connected to the absorption unit and the electrolysis unit, and is used for heat exchange between the absorption unit and the electrolysis unit.

9. The system according to claim 8, characterized in that The second heat exchange unit 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 unit is connected to the second outlet of the absorption unit, the hot end outlet of the second heat exchange unit is connected to the inlet of the anode chamber, the hot end inlet of the second heat exchange unit is connected to the outlet of the cathode chamber, and the cold end outlet of the second heat exchange unit is connected to the second inlet of the absorption unit.

10. An electrochemical carbon dioxide capture method coupled with metal refining, characterized in that: Using the electrochemical carbon dioxide capture system coupled with metal refining according to any one of claims 1 to 9, the method comprises: Step 1, transporting flue gas containing carbon dioxide to the absorption unit, and absorbing carbon dioxide in the flue gas through the absorbent in the absorption unit to obtain absorption liquid and purified gas; Step 2, transporting the absorption liquid to the anode chamber of the electrolysis unit, desorbing the absorption liquid under the action of the crude copper anode, wherein the elements in the crude copper anode that are more active than metallic copper are dissolved into the absorption liquid to obtain a gas mixture containing a copper / ammonia coordination compound and carbon dioxide; Step 3, performing gas-liquid separation on the gas-liquid mixture through the gas-liquid separation unit to obtain carbon dioxide gas and separation liquid; Step 4, transporting the separated liquid to the cathode chamber of the electrolytic desorption unit, so that the copper ions in the separated liquid are electro-deposited under the action of the refined copper cathode to obtain refined copper and absorbent; Step five: transporting the absorbent in the cathode chamber to the absorption unit to continue absorbing carbon dioxide in the flue gas.

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