Carbon dioxide capture and absorbent purification system and method coupled with metal refining

Abstract

The present invention provides a carbon dioxide capture and absorbent purification system and method coupled with metal refining. The system includes an absorption module having an absorbent, a regeneration module having an electrolytic desorption unit and a gas-liquid separation unit, and a purification module. The absorption module is connected to flue gas. The regeneration module and the purification module selectively connect to the absorption module to selectively regenerate and purify the absorbent. The electrolytic desorption unit includes a first anode chamber containing a blister copper anode and a first cathode chamber containing a refined copper cathode. The first outlet of the absorption module connects to the inlet of the first anode chamber, and the second outlet of the absorption module connects to a purified gas pipeline. The inlet of the gas-liquid separation unit connects to the first anode chamber, the first outlet of the gas-liquid separation unit connects to the first cathode chamber, and the second outlet of the gas-liquid separation unit connects to an exhaust pipeline. The outlet of the first cathode chamber connects to the second inlet of the absorption module. This system has high energy efficiency, low energy consumption, low cost, and high capture efficiency.

Description

Technical Field

[0001] The present invention belongs to the technical field of gas purification and separation, and in particular relates to a carbon dioxide capture and absorbent purification system and method coupled with metal refining. Background Art

[0002] Carbon dioxide (CO2) is the primary greenhouse gas contributing to global warming, and its capture, utilization, and storage have become a hot topic of international concern. CO2 emissions from coal-fired power generation in my country account for approximately 50% of total industrial emissions, making the capture and separation of CO2 from coal-fired power plant flue gases a key area of ​​greenhouse gas reduction. Furthermore, numerous CO2 capture or separation processes are also present in industries such as steelmaking, cement, and the chemical industry (such as synthetic ammonia, hydrogen production, and natural gas purification). The main methods for capturing CO2 include absorption, adsorption, membrane separation, and cryogenic separation. Absorption is currently the most mature CO2 capture and separation technology and is expected to achieve large-scale commercial application.

[0003] Existing CO2 capture and separation methods, which solely capture CO2, incur high energy consumption and operating costs. In particular, the steam heat consumed for absorbent regeneration accounts for the vast majority of total system energy consumption, which is inconsistent with the concept of green environmental protection. Furthermore, during the electrolytic regeneration process, the electricity consumed is only used for absorbent regeneration, resulting in low energy efficiency.

[0004] In view of the above problems, it is necessary to propose a carbon dioxide capture and absorbent purification 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 a carbon dioxide capture and absorbent purification system and method coupled with metal refining.

[0006] One aspect of the present invention provides a carbon dioxide capture and absorbent purification system coupled with metal refining, comprising an absorption module provided with an absorbent, a regeneration module having an electrodesorption unit and a gas-liquid separation unit, and a purification module;

[0007] The absorption module is used to communicate with the flue gas containing carbon dioxide so as to absorb the carbon dioxide in the flue gas through the absorbent;

[0008] The regeneration module and the purification module are selectively connected to the absorption module to selectively regenerate and purify the absorbent based on the effective concentration of the absorbent in the absorption module; wherein,

[0009] The electrodesorption unit comprises a first anode chamber and a first cathode chamber which are separated from each other, wherein a crude copper anode is arranged in the first anode chamber, and a refined copper cathode is arranged in the first cathode chamber;

[0010] The first outlet of the absorption module is connected to the inlet of the first anode chamber through the first absorption liquid pipeline, and the second outlet of the absorption module is connected to the purified gas pipeline; the inlet of the gas-liquid separation unit is connected to the first anode chamber, the first outlet of the gas-liquid separation unit is connected to the first cathode chamber, and the second outlet of the gas-liquid separation unit is connected to the exhaust pipeline to discharge the separated carbon dioxide;

[0011] The outlet of the first cathode chamber is connected to the second inlet of the absorption module through a first absorbent pipeline to provide absorbent into the absorption module.

[0012] Optionally, a first control valve is provided on the first absorption liquid pipeline, and a second control valve is provided on the first absorbent pipeline.

[0013] Optionally, the purification module includes a liquid storage tank and an electrolytic purification tank;

[0014] The electrolytic purification tank is provided with a second anode chamber and a second cathode chamber which are spaced apart;

[0015] The inlet of the second cathode chamber is connected to the first outlet of the absorption module through a second absorption liquid pipeline, so that the absorbent to be purified is transported to the second cathode chamber, and the absorbent to be purified undergoes electrodeposition to precipitate metal ions in the absorbent to be purified, thereby obtaining a purified absorbent;

[0016] The outlet of the second cathode chamber is connected to the second inlet of the absorption module through a second absorbent pipeline to transport the purified absorbent to the absorption module;

[0017] The outlet of the liquid storage tank is communicated with the inlet of the second anode chamber, and the outlet of the second anode chamber is communicated with the inlet of the liquid storage tank to provide electrolyte solution to the electrolytic purification tank.

[0018] Optionally, a third control valve is provided on the second absorption liquid pipeline, and a fourth control valve is provided on the second absorbent pipeline.

[0019] Optionally, a rinsing module is also included;

[0020] The first inlet of the elution module is connected to the second outlet of the absorption module through the purified gas pipeline;

[0021] The second inlet of the rinsing module is used to be connected to the rinsing water source;

[0022] The first outlet of the elution module is connected to the gas exhaust pipeline.

[0023] Optionally, a desulfurization module is also included;

[0024] The first inlet of the desulfurization module is used to communicate with the flue gas containing carbon dioxide, and the first outlet of the desulfurization module is connected to the first inlet of the absorption module;

[0025] The second inlet of the desulfurization module is connected to the second outlet of the elution module;

[0026] The reflux outlet of the desulfurization module is communicated with the reflux inlet of the elution module.

[0027] Optionally, a recycling module is also included;

[0028] The inlet of the recovery module is connected to the reflux outlet of the desulfurization module, so that when the desulfurization liquid in the desulfurization module reaches saturation, the liquid material in the desulfurization module is transported to the recovery module for processing.

[0029] Optionally, it further includes a first heat exchange module and a second heat exchange module;

[0030] The first heat exchange module is respectively connected to the elution module and the desulfurization module, and is used for heat exchange between the elution module and the desulfurization module;

[0031] The second heat exchange module is communicated with the absorption module and the electrodesorption unit respectively, and is used for heat exchange between the absorption module and the electrodesorption unit.

[0032] Optionally, the gas-liquid separation unit includes a flash tank and a condenser;

[0033] The gas-liquid mixture inlet of the flash tank is connected to the outlet of the first anode chamber, the gas to be condensed inlet of the condenser is connected to the gas to be condensed outlet 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 first cathode chamber is connected to the separated liquid outlet of the flash tank;

[0034] The top of the condenser is connected to the exhaust pipe for discharging the separated carbon dioxide.

[0035] Another aspect of the present invention provides a method for carbon dioxide capture and absorbent purification coupled with metal refining, using the aforementioned carbon dioxide capture and absorbent purification system coupled with metal refining, the method comprising:

[0036] Step S1, transporting flue gas containing carbon dioxide to the absorption module, and absorbing carbon dioxide in the flue gas through the absorbent in the absorption module to obtain absorption liquid and purified gas;

[0037] Step S2, transporting the absorption liquid to the first anode chamber of the electrodesorption unit, and desorbing the absorption liquid under the action of the crude copper anode, wherein elements in the crude copper anode that are more active than metallic copper dissolve into the absorption liquid to obtain a gas-liquid mixture containing a copper / ammonia coordination compound and carbon dioxide;

[0038] Step S3, performing gas-liquid separation on the gas-liquid mixture by the gas-liquid separation unit to obtain carbon dioxide gas and separated liquid;

[0039] Step S4, transporting the separated liquid to the first cathode chamber of the electrodesorption unit, so that the copper ions in the separated liquid undergo electrodeposition under the action of the refined copper cathode to obtain refined copper and absorbent;

[0040] Step S5, transporting the absorbent in the first cathode chamber to the absorption module to continue absorbing carbon dioxide in the flue gas and realize regeneration of the absorbent; wherein, when the effective concentration of the absorbent is lower than the preset concentration, the regeneration module is disconnected from the absorption module, and the purification module is connected to the absorption module to purify the absorbent; when the effective concentration of the absorbent reaches the preset concentration, the purification module is disconnected from the absorption module, and the regeneration module is connected to the absorption module.

[0041] The present invention relates to a carbon dioxide capture and absorbent purification system and method coupled with metal refining. The system of the present invention adopts an electric cycle carbon capture method to couple the carbon dioxide capture, the metal copper refining process, and the absorbent purification process, resulting in higher energy efficiency, lower energy consumption, and lower operating costs. The carbon dioxide-rich liquid enters the first anode chamber and the first cathode chamber in sequence, thereby improving the regeneration efficiency of the carbon dioxide-rich liquid. The absorbent produced by the electroplating effect in the first cathode chamber enters the absorption module again to absorb carbon dioxide, thereby realizing the recycling of ammonia and the recovery of deposited metals. The system has low energy consumption requirements and low operating costs, thereby 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 metal copper can also be refined to obtain refined copper of higher purity, which is in line with the concept of green environmental protection. In addition, the purification module is selectively connected to the absorption module to purify the absorbent, so that the absorbent concentration meets the corresponding requirements and improves the carbon dioxide capture efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1This is a schematic structural diagram of a carbon dioxide capture and absorbent purification system and method coupled with metal refining according to one embodiment of the present invention;

[0043] Figure 2 This is a schematic structural diagram of an absorption module according to another embodiment of the present invention;

[0044] Figure 3 Schematic diagram of a process for carbon dioxide capture and absorbent purification coupled with metal refining in another embodiment of the present invention. DETAILED DESCRIPTION

[0045] 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 with reference to the accompanying drawings and specific implementation methods.

[0046] like Figure 1 As shown, one aspect of the present invention provides a carbon dioxide capture and absorbent purification system and method coupled with metal refining, comprising an absorption module A provided with an absorbent, a regeneration module B having an electrodesorption unit 2 and a gas-liquid separation unit 3, and a purification module C. The absorption module A is configured to communicate with flue gas containing carbon dioxide so that the absorbent absorbs carbon dioxide from the flue gas.

[0047] 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 can be selected according to actual needs. In this embodiment, the absorbent is an ammonia solution as an example for description.

[0048] The flue gas containing carbon dioxide enters absorption module A through the first inlet of absorption module A. The ammonia-containing solution absorbent in absorption module A absorbs the carbon dioxide to produce absorption liquid and purified gas. The absorption liquid is a high-carbon dioxide-loaded liquid obtained after the absorbent absorbs the carbon dioxide, and the purified gas is the gas obtained after the carbon dioxide is removed from the flue gas.

[0049] The regeneration module B and the purification module C are selectively connected to the absorption module A to selectively regenerate and purify the absorbent based on the effective concentration of the absorbent in the absorption module A.

[0050] Specifically, when the effective concentration of the absorbent is lower than a preset concentration, the regeneration module B is disconnected from the absorption module A, and the purification module C is connected to the absorption module A to purify the absorbent. When the effective concentration of the absorbent reaches a preset concentration, the purification module C is disconnected from the absorption module A, and the regeneration module B is connected to the absorption module A. The effective concentration of the absorbent is always maintained at the preset concentration, thereby increasing the carbon dioxide capture efficiency.

[0051] like Figure 1 As shown, the electrodesorption unit 2 includes a first anode chamber 21 and a first cathode chamber 22, each separated from the other. A blister copper anode is located in the first anode chamber 21, and a refined copper cathode is located in the first cathode chamber 22. Specifically, the electrodes in the first anode chamber 21 are blister copper plates, while the electrodes in the first cathode chamber 22 are refined copper plates. The first anode chamber 21 and the first cathode chamber 22 are separated by an anion exchange membrane 23.

[0052] The first anode chamber 21 houses a crude copper anode, and the first cathode chamber 22 houses a refined copper cathode. Crude copper contains a high concentration of impurities, such as lead and antimony. During the electrolysis process, these impurity metals dissolve into ions along with the copper. Since metals like gold, platinum, and silver are less reactive than copper, they precipitate directly beneath the anode, forming anode mud. This separates the impurities from the copper and improves the copper's purity. Crude copper also contains a large amount of chemical substances, such as copper oxide. In the electrolyte solution, this copper oxide is reduced to pure copper, increasing the reduction reaction during the refining process and improving the copper refining efficiency. Through this process, the crude copper on the anode is gradually dissolved, while impurities are removed or precipitated. The resulting product is high-purity copper ions, which can then be electrodeposited at the cathode to form high-purity refined copper, providing high-quality raw material for the refined copper at the cathode. This system, while absorbing carbon dioxide, can also refine metallic copper, producing high-purity refined copper, in line with environmentally friendly principles.

[0053] It should be noted that in addition to 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 achieved during the carbon dioxide capture process. The electrode types in the anode chamber and cathode chamber can be selected according to actual needs.

[0054] The electrodesorption unit 2 utilizes electrochemical principles and employs an electrochemical cycle with high energy utilization. By supplying power to the electrodesorption unit 2, carbon dioxide desorption and ammonia regeneration can be achieved. Specifically, carbon dioxide desorption is achieved as follows: because the electrodes of the first anode chamber 21 contain copper elements that can coordinate with ammonia, the electrodes of the first anode chamber 21 can produce corresponding metallic copper ions. Through the coordination and binding of the metallic copper ions with ammonia, carbon dioxide in the absorption liquid can be desorbed, thereby reducing energy consumption while ensuring carbon dioxide desorption. Simultaneously, during the electrodesorption process, elements in the crude copper anode that are more active than metallic copper dissolve into the absorption liquid, separating impurities in the crude copper anode and obtaining copper ions of higher purity.

[0055] The first outlet of the absorption module A is connected to the inlet of the first anode chamber 21 through the first absorption liquid pipeline 41, so that the absorption liquid is transported to the first anode chamber 21 through the first absorption liquid pipeline 41. The absorption liquid is desorbed under the action of the crude copper anode, wherein the desorption process of carbon dioxide in the first anode chamber 21 is specifically as follows: Cu-2e - =Cu 2+ ;Cu 2+ +nNH3-CO2=Cu(NH3) n 2+ +CO2↑.

[0056] Elements in the crude copper anode that are more reactive than metallic copper dissolve into the absorption liquid, producing a gas-liquid mixture containing a copper / ammonia coordination compound and carbon dioxide. The liquid component of the gas-liquid mixture has a low carbon dioxide loading and a high metal loading, primarily because the carbon dioxide is mostly present in gaseous form.

[0057] The electrodesorption unit 2 utilizes electrochemical principles and employs an electrochemical cycle with high energy utilization. By supplying power to the electrodesorption unit 2, carbon dioxide desorption and ammonia regeneration can be achieved. Specifically, carbon dioxide desorption is achieved as follows: because the electrodes of the first anode chamber 21 contain copper elements that can coordinate with ammonia, the electrodes of the first anode chamber 21 can produce corresponding metallic copper ions. Through the coordination and binding of the metallic copper ions with ammonia, carbon dioxide in the absorption liquid can be desorbed, thereby reducing energy consumption while ensuring carbon dioxide desorption. Simultaneously, during the electrodesorption process, elements in the crude copper anode that are more active than metallic copper dissolve into the absorption liquid, separating impurities in the crude copper anode and obtaining copper ions of higher purity.

[0058] The second outlet of the absorption module A 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.

[0059] The inlet of the gas-liquid separation unit 3 is connected to the first anode chamber 21, the first outlet of the gas-liquid separation unit 3 is connected to the first cathode chamber 2, and the second outlet of the gas-liquid separation unit 3 is connected to the exhaust pipe to discharge the separated carbon dioxide.

[0060] Specifically, the gas-liquid mixture produced by the first anode chamber 21 is transported to the gas-liquid separation unit 3 via the gas-liquid mixture pipeline 43. The gas-liquid separation unit 3 separates the gas-liquid mixture into carbon dioxide gas and a separated liquid. Because ammonia is already coordinated with the metallic copper ions, the gaseous carbon dioxide can be relatively easily separated from the gas-liquid mixture. The separated carbon dioxide gas is discharged through the second first outlet of the gas-liquid separation unit 3.

[0061] The second outlet of the gas-liquid separation unit 3 is connected to the inlet of the first cathode chamber 22 through the separation liquid pipeline 44, and the separation liquid is transported to the first cathode chamber 22 of the electrodesorption 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 ammonia-containing solution. The process of the electro-deposition is: Cu(NH3) n 2+ +2e - =Cu+nNH 3。 The ammonia-containing solution in the first cathode chamber 22 has a low carbon dioxide load and a low metallic copper load. Through the electrodeposition of the separation liquid in the first cathode chamber 22, ammonia is regenerated and refined copper is recovered, saving resources and complying with the concept of green environmental protection.

[0062] The outlet of the first cathode chamber 22 is connected to the second inlet of the absorption module A through the first absorbent pipe 45, and the ammonia-containing solution produced in the first cathode chamber 22 is transported to the absorption module A through the first absorbent pipe 45 to provide the ammonia-containing solution to the absorption module A, continue to absorb the carbon dioxide in the flue gas, realize the recycling of ammonia, and thus realize the complete carbon dioxide capture cycle.

[0063] Specifically, in the entire system of the present invention, carbon dioxide is absorbed in the absorption module by an ammonia-containing solution; by using a crude copper metal plate coordinated with ammonia as the electrode of the first anode chamber, the absorption liquid is desorbed under the action of the crude copper anode, wherein, in the first anode chamber, elements in the crude copper anode that are more active than metallic copper dissolve into the absorption liquid, and copper ions can be released into the carbon dioxide-loaded absorption liquid by electrochemical dissolution in the first anode chamber, and carbon dioxide is desorbed by coordination with ammonia to obtain a gas-liquid 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 separated liquid; the separated liquid undergoes electrodeposition under the action of the refined copper cathode in the first cathode chamber, and copper ions are deposited to the cathode to obtain refined copper and an ammonia-containing solution, thereby realizing ammonia regeneration; finally, the ammonia-containing solution enters the absorption module again to provide the absorption module with ammonia-containing solution, thereby ensuring the supply of absorbent in the subsequent carbon dioxide capture process in the absorption unit.

[0064] When the effective concentration of the absorbent is lower than a preset concentration, the regeneration module is disconnected from the absorption module, and the purification module is connected to the absorption module to purify the absorbent. When the effective concentration of the absorbent reaches a preset concentration, the purification module is disconnected from the absorption module, and the regeneration module is connected to the absorption module, so as to always maintain the effective concentration of the absorbent at the preset concentration and increase the carbon dioxide capture efficiency.

[0065] The carbon dioxide capture and absorbent purification system coupled with metal refining of the present invention adopts an electric cycle carbon capture method to couple the carbon dioxide capture, the metal copper refining process and the absorbent purification process, which has higher energy efficiency, lower energy consumption and lower operating costs; the carbon dioxide rich liquid enters the first anode chamber and the first cathode chamber in sequence, improving the regeneration efficiency of the carbon dioxide rich liquid; the absorbent produced by the electrodeposition effect of the first cathode chamber enters the absorption module again to absorb carbon dioxide, realizing the recycling of ammonia and the recovery of deposited metals, with 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 metal copper can also be refined to obtain refined copper with higher purity, which is in line with the concept of green environmental protection. In addition, the purification module is selectively connected to the absorption module to play the role of absorbent purification, so that the absorbent concentration meets the corresponding requirements and improves the carbon dioxide capture efficiency.

[0066] For example, Figure 1 As shown, a first control valve 41a is provided on the first absorption liquid pipeline 41, and a second control valve 45a is provided on the first absorbent pipeline 45. The first control valve 41a controls the opening and closing of the first absorption liquid pipeline 41, and the second control valve 45a controls the opening and closing of the first absorbent pipeline 45, thereby controlling whether the absorbent is regenerated.

[0067] For example, Figure 1 As shown, the purification module C includes a liquid storage tank 51 and an electrolytic purification cell. The electrolytic purification cell is provided with a second anode chamber 52 and a second cathode chamber 53, which are spaced apart. The second cathode chamber 53 contains a metal electrode plate, allowing metal ions in the absorbent to undergo electrodeposition at the metal electrode plate.

[0068] The inlet of the second cathode chamber 53 is connected to the first outlet of the absorption module A through the second absorption liquid pipeline 54, so that the absorbent to be purified is transported to the second cathode chamber 53, so that the absorbent to be purified undergoes electrodeposition to precipitate the metal ions in the absorbent to be purified, thereby obtaining a purified absorbent.

[0069] The outlet of the second cathode chamber 53 is connected to the second inlet of the absorption module A through the second absorbent pipe 55 to transport the purified absorbent to the absorption module A, provide the absorption module A with purified absorbent, continue to absorb carbon dioxide in the flue gas, realize the recycling of ammonia, and thus realize a complete carbon dioxide capture cycle and increase the carbon dioxide capture efficiency.

[0070] The outlet of the liquid storage tank 51 is connected to the inlet of the second anode chamber 52, and the outlet of the second anode chamber 52 is connected to the inlet of the liquid storage tank 51 to provide an electrolyte solution to the electrolytic purification cell. The electrolyte solution can be Na2SO4, NaCl, NaNO3, K2SO4, etc., and can be selected according to actual needs.

[0071] In this embodiment, by providing a purification module selectively connected to the bottom of the absorption module and increasing the voltage, the active impurity elements of the absorbent in the absorption module can be deposited in the second cathode chamber, thereby purifying the absorbent and increasing the carbon dioxide capture efficiency.

[0072] For example, Figure 1 As shown, a third control valve 54a is provided on the second absorption liquid pipeline 54, and a fourth control valve 55a is provided on the second absorbent pipeline 55. The third control valve 54a controls the opening and closing of the second absorption liquid pipeline 54, and the fourth control valve 55a controls the opening and closing of the second absorbent pipeline 55, thereby controlling whether the absorbent is purified.

[0073] Specifically, when the absorbent needs to be regenerated, the first and second control valves are opened, and the third and fourth control valves are closed, allowing the absorbent in the absorption module to enter the electrodesorption unit for regeneration. When the absorbent needs to be purified, the first and second control valves are closed, and the third and fourth control valves are opened, allowing the absorbent in the absorption module to enter the purification module for purification.

[0074] For example, Figure 1 As shown, the carbon dioxide capture and absorbent purification system coupled with metal refining of the present invention further includes a rinse module 5. A first inlet of the rinse module 5 is connected to a second outlet of the absorption module A via a purified gas pipeline 42. The second inlet of the rinse module 5 is connected to a rinse water source. The first outlet of the rinse module 5 is connected to a gas exhaust pipeline 46.

[0075] Specifically, the purified gas generated in absorption module A contains residual ammonia. This purified gas containing ammonia is transmitted to the elution module 5 via the purified gas pipeline 42. The elution water source enters the elution module 5 via the second inlet to elute the purified gas containing ammonia, thereby separating and recovering the residual ammonia. The separated ammonia exists as an ammonia-containing eluent, resulting in an ammonia-containing solution and the gas to be discharged. The gas to be discharged is discharged through the gas discharge pipeline 46.

[0076] For example, Figure 1As shown, the carbon dioxide capture and absorbent purification system coupled with metal refining of the present invention further includes a desulfurization module 6. The first inlet of the desulfurization module 6 is used to communicate with the flue gas containing carbon dioxide. The flue gas containing carbon dioxide first enters the desulfurization module 6 for pretreatment of flue gas desulfurization to obtain a desulfurized liquid.

[0077] The first outlet of the desulfurization module 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.

[0078] The second inlet of the desulfurization module 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 module 6 in the form of ammonia-containing eluent.

[0079] The reflux outlet of the desulfurization module 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.

[0080] 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 module 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.

[0081] It should be noted that the purified gas can be eluted with circulating desulfurization liquid or with externally supplied water. Of course, the purified gas can also be eluted with both desulfurization liquid and externally supplied water. The choice can be made according to actual needs.

[0082] For example, Figure 1 As shown, the carbon dioxide capture and absorbent purification system coupled with metal refining of the present invention also includes a recovery module 7, the inlet of the recovery module 7 is connected to the reflux outlet of the desulfurization module 6, so that when the desulfurization liquid in the desulfurization module reaches saturation, the liquid material in the desulfurization module 6 is transported to the recovery module 7 for processing.

[0083] Specifically, when the desulfurization liquid reaches saturation, the liquid material in the desulfurization module 6 can be transported to the recovery module 7 for processing to obtain a usable sulfur dioxide, such as ammonium sulfate fertilizer. The recovery module 7 allows the desulfurization liquid to be recycled and reused, saving resources.

[0084] For example, Figure 1 As shown, the carbon dioxide capture and absorbent purification system coupled with metal refining of the present invention further includes a first heat exchange module 8, which is connected to the elution unit 5 and the desulfurization module 6 respectively, and is used for heat exchange between the elution unit 5 and the desulfurization module 6.

[0085] Specifically, the ammonia-containing eluent and the desulfurization liquid can undergo heat exchange through the first heat exchange module 8. This heat exchange between the ammonia-containing eluent and the desulfurization liquid is performed through the first heat exchange module 8, transferring heat from the desulfurization liquid to the ammonia-containing eluent. Furthermore, after the heat exchange, the ammonia-containing eluent can be further heated by a heating component while being transported to the desulfurization unit 6 to promote desulfurization in the desulfurization unit 6. Furthermore, after the heat exchange, the desulfurization liquid can be further cooled by a cooling component while being transported to the elution unit 5.

[0086] In this embodiment, the first heat exchange module improves the heat utilization rate of the entire system and saves energy.

[0087] For example, Figure 1 As shown, the carbon dioxide capture and absorbent purification system coupled with metal refining of the present invention further includes a second heat exchange module 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.

[0088] Specifically, the second heat exchange module 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 module 9 is connected to the second outlet of the absorption unit 1, the hot end outlet of the second heat exchange module 9 is connected to the inlet of the first anode chamber 21, the hot end inlet of the second heat exchange module 9 is connected to the outlet of the first cathode chamber 22, and the cold end outlet of the second heat exchange module 9 is connected to the second inlet of the absorption unit 1.

[0089] In this embodiment, the ammoniated solution and the absorption liquid exchange heat only through the second heat exchange module 9, transferring the heat of the ammoniated solution to the absorption liquid, and the ammoniated solution and the absorption liquid are isolated from each other in the second heat exchange module 9. The delivery channel between the cold end outlet of the second heat exchange module 9 and the ammoniated solution inlet of the absorption unit 1 is used to deliver the ammoniated solution to the absorption unit 1, and a cooling component can be installed on the delivery channel; the delivery channel between the hot end outlet of the second heat exchange module 9 and the inlet of the first anode chamber 21 is used to deliver the absorption liquid to the first anode chamber 21, and a heating component can be installed on the delivery channel.

[0090] For example, Figure 1 As shown, the gas-liquid separation unit 3 includes a flash tank 31 and a condenser 32 .

[0091] The gas-liquid mixture inlet of the flash tank 31 is connected to the outlet of the first anode chamber 21, the gas to be condensed inlet of the condenser 32 is connected to the gas to be condensed outlet 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 first 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.

[0092] 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 .

[0093] For example, Figure 2 As shown, the absorption module A 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 .

[0094] The absorption section 11 is located at the bottom of the absorption module A, and the condensation section 12 is located at the top of the absorption module A. The isolation plate 12 allows gas to pass through while blocking liquid substances from passing through. The isolation plate 12 may be made of a PTFE film, preferably a Teflon PTFE film.

[0095] 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 first cathode chamber 22.

[0096] The absorption liquid outlet of the condensation part 12 is connected to the first absorption liquid pipeline 41 , and the gas outlet of the condensation part 12 is connected to the purified gas pipeline 42 .

[0097] 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.

[0098] Specifically, flue gas containing carbon dioxide enters the absorption section 11 through the flue gas inlet, and the absorbent enters the absorption section 11 through the absorbent inlet, where it absorbs the carbon dioxide. After the absorbent absorbs the carbon dioxide, it is transported to the condensation section 12 through the pipeline. The purified gas obtained after absorption is discharged from the gas outlet, and the absorption liquid obtained after absorbing the carbon dioxide is discharged into the first anode chamber 21. It should be noted that due to the installation of a cooling component in the pipeline, ammonia can be kept in solution, thereby preventing ammonia volatilization and ensuring the recycling of ammonia.

[0099] In this embodiment, the gas-liquid separation unit 3 includes a flash tank 31 and a condenser 32 , which can separate the gas-liquid mixture, reduce ammonia loss, and lower the energy consumption of the entire system.

[0100] like Figure 3 Another aspect of the present invention provides a method for carbon dioxide capture and absorbent purification coupled to metal refining, using the aforementioned carbon dioxide capture and absorbent purification system coupled to metal refining. The specific structure of the carbon dioxide capture and absorbent purification system coupled to metal refining has been described in detail above and will not be repeated here. The method comprises:

[0101] In step S1, flue gas containing carbon dioxide is transported to the absorption module, and the carbon dioxide in the flue gas is absorbed by the absorbent in the absorption module to obtain absorption liquid and purified gas.

[0102] Specifically, the ammonia-containing solution in the absorption module may contain a supporting electrolyte, which may be potassium chloride, sodium chloride, sodium sulfate or the like. In addition, some additives may be added to the ammonia-containing solution in the absorption module, such as surfactants such as tetraethylammonium chloride and tetrapropylammonium chloride.

[0103] The absorption liquid is a liquid with a high carbon dioxide load obtained after the ammonia-containing solution absorbs carbon dioxide, and the purified gas refers to the gas obtained after the carbon dioxide is removed from the flue gas.

[0104] Step S2: transporting the absorption liquid to the first anode chamber of the electrodesorption unit, and desorbing the absorption liquid under the action of the crude copper anode, wherein elements in the crude copper anode that are more active than metallic copper dissolve into the absorption liquid to obtain a gas-liquid mixture containing a copper / ammonia coordination compound and carbon dioxide.

[0105] The liquid component of the gas-liquid mixture has a low carbon dioxide loading and a high metal loading, primarily because the majority of carbon dioxide is present in gaseous form. Specifically, carbon dioxide desorption occurs as follows: Since the electrodes in the first anode chamber 21 contain copper elements that can coordinate with ammonia, these electrodes generate corresponding metallic copper ions. These metallic copper ions coordinate with ammonia, desorbing carbon dioxide from the absorption liquid. This reduces energy consumption while ensuring carbon dioxide desorption. Furthermore, during the electrolytic desorption process, elements in the crude copper anode that are more reactive than metallic copper dissolve into the absorption liquid, separating impurities from the crude copper anode and yielding higher-purity copper ions.

[0106] Step S3: performing gas-liquid separation on the gas-liquid mixture through the gas-liquid separation unit to obtain carbon dioxide gas and separated liquid.

[0107] 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.

[0108] Step S4: transporting the separated liquid to the first cathode chamber of the electrodesorption unit, so that the copper ions in the separated liquid undergo electrodeposition under the action of the refined copper cathode to obtain refined copper and absorbent.

[0109] Specifically, copper ions in the separated liquid undergo electrodeposition at the refined copper cathode, producing refined copper and an ammonia-containing solution. The ammonia-containing solution in the first cathode chamber 22 has a low carbon dioxide load and a low metallic copper load. The electrodeposition of the separated liquid in the first cathode chamber 22 regenerates ammonia and recovers refined copper, conserving resources and complying with environmental protection principles.

[0110] Step S5, transporting the absorbent in the first cathode chamber to the absorption module to continue absorbing carbon dioxide in the flue gas and realize regeneration of the absorbent; wherein, when the effective concentration of the absorbent is lower than the preset concentration, the regeneration module is disconnected from the absorption module, and the purification module is connected to the absorption module to purify the absorbent; when the effective concentration of the absorbent reaches the preset concentration, the purification module is disconnected from the absorption module, and the regeneration module is connected to the absorption module.

[0111] Specifically, the ammonia-containing solution produced in the first cathode chamber 22 is transported to the absorption module A through the first ammonia-containing solution pipeline 45 to provide the ammonia-containing solution to the absorption module A, continue to absorb carbon dioxide in the flue gas, realize the recycling of ammonia, and thus realize the complete carbon dioxide capture cycle.

[0112] When the absorbent needs to be regenerated, the first and second control valves are opened, and the third and fourth control valves are closed, allowing the absorbent in the absorption module to enter the electrodesorption unit for regeneration. When the absorbent needs to be purified, the first and second control valves are closed, and the third and fourth control valves are opened, allowing the absorbent in the absorption module to enter the purification module for purification.

[0113] The present invention relates to a method for carbon dioxide capture and absorbent purification coupled with metal refining. The method of the present invention adopts an electric cycle carbon capture method to couple the carbon dioxide capture, the metal copper refining process, and the absorbent purification process, thereby achieving higher energy efficiency, lower energy consumption, and lower operating costs. The carbon dioxide-rich liquid enters the first anode chamber and the first cathode chamber in sequence, thereby improving the regeneration efficiency of the carbon dioxide-rich liquid. The absorbent produced by the electrodeposition of the first cathode chamber enters the absorption module again to absorb carbon dioxide, thereby achieving the recycling of ammonia and the recovery of deposited metals. The method has low energy consumption requirements and low operating costs, thereby 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 metal copper can also be refined to obtain refined copper of higher purity, which is in line with the concept of green environmental protection. In addition, the purification module is selectively connected to the absorption module to purify the absorbent, so that the absorbent concentration meets the corresponding requirements and improves the carbon dioxide capture efficiency.

[0114] It will be understood that the above embodiments are merely exemplary embodiments for illustrating the principles of the present invention, and the present invention is not limited thereto. Those skilled in the art will appreciate that various modifications and improvements can be made without departing from the spirit and substance of the present invention, and such modifications and improvements are also considered to be within the scope of protection of the present invention.

Claims

1. A carbon dioxide capture and absorbent purification system coupled with metal refining, characterized in that: It includes an absorption module provided with an absorbent, a regeneration module having an electric desorption unit and a gas-liquid separation unit, and a purification module; The absorption module is used to communicate with the flue gas containing carbon dioxide so as to absorb the carbon dioxide in the flue gas through the absorbent; The regeneration module and the purification module are selectively connected to the absorption module to selectively regenerate and purify the absorbent based on the effective concentration of the absorbent in the absorption module; wherein, The electrodesorption unit comprises a first anode chamber and a first cathode chamber which are separated from each other, wherein a crude copper anode is arranged in the first anode chamber, and a refined copper cathode is arranged in the first cathode chamber; The first outlet of the absorption module is connected to the inlet of the first anode chamber through the first absorption liquid pipeline, and the second outlet of the absorption module is connected to the purified gas pipeline; the inlet of the gas-liquid separation unit is connected to the first anode chamber, the first outlet of the gas-liquid separation unit is connected to the first cathode chamber, and the second outlet of the gas-liquid separation unit is connected to the exhaust pipeline to discharge the separated carbon dioxide; The outlet of the first cathode chamber is connected to the second inlet of the absorption module through a first absorbent pipeline to provide absorbent into the absorption module; wherein, A first control valve is provided on the first absorption liquid pipeline, and a second control valve is provided on the first absorbent pipeline; The purification module includes a liquid storage tank and an electrolytic purification tank; The electrolytic purification tank is provided with a second anode chamber and a second cathode chamber which are spaced apart; The inlet of the second cathode chamber is connected to the first outlet of the absorption module through a second absorption liquid pipeline, so that the absorbent to be purified is transported to the second cathode chamber, and the absorbent to be purified undergoes electrodeposition to precipitate metal ions in the absorbent to be purified, thereby obtaining a purified absorbent; The outlet of the second cathode chamber is connected to the second inlet of the absorption module through a second absorbent pipeline to transport the purified absorbent to the absorption module; The outlet of the liquid storage tank is connected to the inlet of the second anode chamber, and the outlet of the second anode chamber is connected to the inlet of the liquid storage tank to provide electrolyte solution to the electrolytic purification tank; The second absorption liquid pipeline is provided with a third control valve, and the second absorbent pipeline is provided with a fourth control valve.

2. The system according to claim 1, wherein: Also includes a rinsing module; The first inlet of the elution module is connected to the second outlet of the absorption module through the purified gas pipeline; The second inlet of the rinsing module is used to be connected to the rinsing water source; The first outlet of the elution module is connected to the gas exhaust pipeline.

3. The system according to claim 2, characterized in that It also includes a desulfurization module; The first inlet of the desulfurization module is used to communicate with the flue gas containing carbon dioxide, and the first outlet of the desulfurization module is connected to the first inlet of the absorption module; The second inlet of the desulfurization module is connected to the second outlet of the elution module; The reflux outlet of the desulfurization module is communicated with the reflux inlet of the elution module.

4. The system according to claim 3, characterized in that Also includes a recycling module; The inlet of the recovery module is connected to the reflux outlet of the desulfurization module, so that when the desulfurization liquid in the desulfurization module reaches saturation, the liquid material in the desulfurization module is transported to the recovery module for processing.

5. The system according to claim 3, wherein: Also includes a first heat exchange module and a second heat exchange module; The first heat exchange module is respectively connected to the elution module and the desulfurization module, and is used for heat exchange between the elution module and the desulfurization module; The second heat exchange module is communicated with the absorption module and the electrodesorption unit respectively, and is used for heat exchange between the absorption module and the electrodesorption unit.

6. The system according to any one of claims 1 to 5, characterized in that The gas-liquid separation unit includes a flash tank and a condenser; The gas-liquid mixture inlet of the flash tank is connected to the outlet of the first anode chamber, the gas to be condensed inlet of the condenser is connected to the gas to be condensed outlet 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 first cathode chamber is connected to the separated liquid outlet of the flash tank; The top of the condenser is connected to the exhaust pipe for discharging the separated carbon dioxide.

7. A method for carbon dioxide capture and absorbent purification coupled with metal refining, characterized in that: The carbon dioxide capture and absorbent purification system coupled with metal refining according to any one of claims 1 to 6 is used, wherein the method comprises: Step S1, transporting flue gas containing carbon dioxide to the absorption module, and absorbing carbon dioxide in the flue gas through the absorbent in the absorption module to obtain absorption liquid and purified gas; Step S2, transporting the absorption liquid to the first anode chamber of the electrodesorption unit, and desorbing the absorption liquid under the action of the crude copper anode, wherein elements in the crude copper anode that are more active than metallic copper dissolve into the absorption liquid to obtain a gas-liquid mixture containing a copper / ammonia coordination compound and carbon dioxide; Step S3, performing gas-liquid separation on the gas-liquid mixture by the gas-liquid separation unit to obtain carbon dioxide gas and separated liquid; Step S4, transporting the separated liquid to the first cathode chamber of the electrodesorption unit, so that the copper ions in the separated liquid undergo electrodeposition under the action of the refined copper cathode to obtain refined copper and absorbent; Step S5, transporting the absorbent in the first cathode chamber to the absorption module to continue absorbing carbon dioxide in the flue gas and realize regeneration of the absorbent; wherein, when the effective concentration of the absorbent is lower than the preset concentration, the regeneration module is disconnected from the absorption module, and the purification module is connected to the absorption module to purify the absorbent; when the effective concentration of the absorbent reaches the preset concentration, the purification module is disconnected from the absorption module, and the regeneration module is connected to the absorption module.

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