System and method for collecting carbon dioxide

Abstract

The invention relates to the technical field of tail gas purification, and discloses a carbon dioxide trapping system and method. The absorbent and carbon dioxide in the tail gas react in the absorption device to form a carbon dioxide rich solution, and the battery device takes the carbon dioxide rich solution as an electrolyte to carry out primary battery reaction, so that carbon dioxide is desorbed from the carbon dioxide rich solution, and tail gas purification is realized. High-temperature desorption and carbon dioxide compression liquefaction processes are avoided, energy consumption can be reduced, and the tail gas purification cost can be reduced. And moreover, carbon dioxide in the rich liquor is converted into salts through primary battery reaction, and the carbon dioxide is stored in a solid form, so that the transfer and transportation difficulty can be reduced, and the tail gas purification cost can be reduced. Besides, the battery device comprises the carbon positive electrode and the metal negative electrode, and the carbon dioxide rich solution is used as the electrolyte to carry out primary battery reaction, so that the carbon dioxide can be efficiently captured, and the miniaturization design of the battery device is facilitated.

Description

Technical Field

[0001] The present application relates to the technical field of exhaust gas purification, and in particular to a carbon dioxide capture system and capture method. Background Art

[0002] The use of low-carbon and zero-carbon fuels is the fundamental means to achieve zero-carbon emissions in the shipping industry, but there are still a series of problems such as high cost of green fuel synthesis, insufficient supply, and imperfect industrial chain, which makes it difficult to achieve rapid replacement of traditional energy in the short term. The forecast results of various professional institutions show that traditional diesel and LNG (Liquefied Natural Gas) power will still account for a large proportion of the ship energy structure in the future for a long period of time. How to solve the problem of ship carbon emissions under the existing energy power form has gradually become the focus of the shipping industry.

[0003] Carbon capture technology based on chemical absorption is an important technical means to achieve large-scale decarbonization. It has the advantages of large emission reduction, good adaptability to ships, and easy transformation. It can achieve significant emission reduction effects in a relatively short period of time with low initial investment, thereby meeting the requirements of ship GHG (greenhouse gas) emission compliance. However, the current carbon capture technology involves a series of processes such as high-temperature desorption, high-pressure compression of carbon dioxide, and low-temperature liquefaction, which consumes a large amount of hot steam and electricity, which has a great impact on the economic efficiency of actual ship operations. In addition, the transfer and transportation process of liquid carbon dioxide at the port is very difficult, which greatly increases the operating cost. The above factors lead to high costs for ship exhaust purification. Summary of the invention

[0004] The present application provides a carbon dioxide capture system and capture method, which are beneficial to reducing the cost of exhaust gas purification.

[0005] The present application provides a carbon dioxide capture system. The capture system includes an absorption device, in which an absorbent reacts with carbon dioxide in tail gas to form a carbon dioxide rich liquid. The capture system also includes a battery device, which is connected to the absorption device and is used to receive the carbon dioxide rich liquid. The battery device includes a carbon positive electrode and a metal negative electrode, and the battery device is configured to perform a primary cell reaction using the carbon dioxide rich liquid as an electrolyte to desorb carbon dioxide from the carbon dioxide rich liquid.

[0006] In one embodiment of the present application, the absorbent is an amine absorbent, and the material of the metal negative electrode is magnesium.

[0007] In one embodiment of the present application, the capture system also includes: a circulation tank, the output end of the absorption device is connected to the input end of the battery device through the circulation tank, the carbon dioxide rich liquid is transmitted to the battery device through the circulation tank, and the output end of the battery device is connected to the input end of the absorption device through the circulation tank, and the carbon dioxide lean liquid obtained by the primary battery reaction is transmitted from the battery device to the absorption device through the circulation tank.

[0008] In one embodiment of the present application, the interior of the circulation tank has a partition, which divides the interior of the circulation tank into a first chamber and a second chamber. The output end of the absorption device is connected to the input end of the battery device through the first chamber, and the output end of the battery device is connected to the input end of the absorption device through the second chamber.

[0009] In one embodiment of the present application, the capture system further includes: a first circulation pump, which is arranged between the circulation tank and the input end of the battery device, and the first circulation pump is used to pump the carbon dioxide rich liquid to the battery device.

[0010] In one embodiment of the present application, the capture system further includes: a second circulation pump, disposed between the circulation tank and the input end of the absorption device, and the second circulation pump is used to pump the carbon dioxide lean liquid to the absorption device.

[0011] In one embodiment of the present application, the capture system further includes: a circulation pump, which is connected to the absorption device and the battery device respectively, and the circulation pump is used to pump the carbon dioxide rich liquid to the battery device and / or pump the carbon dioxide lean liquid obtained by the primary cell reaction to the absorption device.

[0012] In one embodiment of the present application, the capture system further includes: a cooling device connected to the absorption device, and the exhaust gas is cooled by the cooling device and then input into the absorption device.

[0013] Correspondingly, the present application also provides a method for capturing carbon dioxide, which is based on the capture system described in the above embodiment, and the capture method includes: inputting the exhaust gas into an absorption device of the capture system, so that the absorbent reacts with the carbon dioxide in the exhaust gas in the absorption device to form a carbon dioxide rich liquid; inputting the carbon dioxide rich liquid into a battery device of the capture system, and the battery device uses the carbon dioxide rich liquid as an electrolyte to perform a primary cell reaction to desorb carbon dioxide from the carbon dioxide rich liquid.

[0014] In one embodiment of the present application, the absorbent is an amine absorbent; the step of reacting the absorbent with carbon dioxide in the tail gas in the absorption device to form a carbon dioxide-rich liquid includes: the absorbent reacts with carbon dioxide in the tail gas to obtain a carbamate solution.

[0015] In one embodiment of the present application, the material of the metal negative electrode of the battery device is magnesium; the step of the battery device performing a primary cell reaction using a carbon dioxide-rich solution as an electrolyte includes: performing a primary cell reaction using a carbamate solution as an electrolyte, and the generated magnesium oxalate adheres to the surface of the carbon positive electrode of the battery device.

[0016] In one embodiment of the present application, after the step of the battery device performing a primary cell reaction using a carbon dioxide-rich liquid as an electrolyte, the step includes: performing an electrolytic cell reaction on the battery device to obtain carbon dioxide and a metal element, wherein the metal element is the same metal as the metal negative electrode of the battery device.

[0017] The beneficial effects of the present application are as follows: Different from the prior art, the present application provides a carbon dioxide capture system and capture method. The absorbent of the present application reacts with the carbon dioxide in the exhaust gas in the absorption device to form a carbon dioxide rich liquid, and the battery device uses the carbon dioxide rich liquid as the electrolyte to perform a primary battery reaction to desorb carbon dioxide from the carbon dioxide rich liquid to achieve exhaust gas purification. The present application avoids high-temperature desorption and carbon dioxide compression and liquefaction processes, can reduce energy consumption, and is beneficial to reducing the cost of exhaust gas purification. Moreover, the carbon dioxide in the rich liquid is converted into salts through the primary battery reaction, and the carbon dioxide is stored in a solid form, which can reduce the difficulty of transfer and transportation, and is beneficial to reducing the cost of exhaust gas purification. In addition, the battery device of the present application includes a carbon positive electrode and a metal negative electrode, and uses the carbon dioxide rich liquid as the electrolyte to perform a primary battery reaction, which can ensure efficient carbon dioxide capture and is beneficial to the miniaturized design of the battery device. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For those skilled in the art, other drawings can be obtained based on these drawings without creative work.

[0019] Figure 1 is a schematic diagram of an embodiment of a carbon dioxide capture system of the present application;

[0020] Figure 2 This is a schematic diagram of the reaction principle of an embodiment of the battery device of the present application;

[0021] Figure 3 It is a schematic flow chart of an embodiment of a method for capturing carbon dioxide of the present application;

[0022] Figure 4 It is a flow chart of another embodiment of the carbon dioxide capture method of the present application.

[0023] Description of reference numerals:

[0024] 10 capture system; 11 absorption device; 111 absorption tower; 112 washing flow path; 12 battery device; 121 carbon positive electrode; 122 metal negative electrode; 13 circulation tank; 131 partition; 132 first chamber; 133 second chamber; 14 first circulation pump; 15 second circulation pump; 16 cooling device; 161 cooling tower; 162 cooling flow path. DETAILED DESCRIPTION

[0025] The technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without making creative work are within the scope of protection of the present application. In addition, it should be understood that the specific implementation methods described herein are only used to illustrate and explain the present application and are not used to limit the present application. In the present application, unless otherwise stated, the directional words used, such as "up", "down", "left", and "right", generally refer to the up, down, left, and right of the device in actual use or working state, specifically the drawing direction in the accompanying drawings.

[0026] In this application, unless otherwise clearly specified and limited, the terms "connected", "connected", "stacked" and the like should be understood in a broad sense, for example, it can be fixedly connected, detachably connected, or integrated; it can be directly connected, or indirectly connected through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0027] The present application provides a carbon dioxide capture system and capture method, which are described in detail below. It should be noted that the description order of the following embodiments does not limit the preferred order of the embodiments of the present application. In the following embodiments, the description of each embodiment has its own emphasis. For parts that are not described in detail in a certain embodiment, please refer to the relevant description of other embodiments.

[0028] In order to solve the technical problem of high cost of ship exhaust purification in the prior art, an embodiment of the present application provides a carbon dioxide capture system. The capture system includes an absorption device, in which an absorbent reacts with carbon dioxide in the exhaust gas to form a carbon dioxide rich liquid. The capture system also includes a battery device, which is connected to the absorption device and is used to receive the carbon dioxide rich liquid. The battery device includes a carbon positive electrode and a metal negative electrode, and the battery device is configured to perform a primary cell reaction using the carbon dioxide rich liquid as an electrolyte to desorb carbon dioxide from the carbon dioxide rich liquid. This is described in detail below.

[0029] See also Figure 1 , Figure 1 It is a schematic diagram of an embodiment of a carbon dioxide capture system of the present application.

[0030] In one embodiment, the capture system 10 can be applied to capture carbon dioxide in exhaust gas emitted by ship engines, etc., to achieve exhaust gas purification. The capture system 10 includes an absorption device 11, which is used to receive exhaust gas. The absorbent reacts with carbon dioxide in the exhaust gas in the absorption device 11 to form a carbon dioxide rich liquid. The capture system 10 also includes a battery device 12, which is connected to the absorption device 11 and is used to receive the carbon dioxide rich liquid. The battery device 12 is configured to perform a primary cell reaction with the carbon dioxide rich liquid as an electrolyte to desorb carbon dioxide from the carbon dioxide rich liquid to achieve exhaust gas purification.

[0031] Through the above-mentioned method, the battery device 12 of this embodiment uses carbon dioxide rich liquid as electrolyte to carry out primary battery reaction, desorbs carbon dioxide from carbon dioxide rich liquid, and then realizes exhaust gas purification. In this way, this embodiment avoids high-temperature desorption and carbon dioxide compression and liquefaction process, can reduce energy consumption, and is conducive to reducing the cost of exhaust gas purification. In addition, the carbon dioxide in the rich liquid is converted into salts through the primary battery reaction, and the carbon dioxide is stored in a solid form, which can reduce the difficulty of transfer and transportation, and is conducive to reducing the cost of exhaust gas purification. In addition, for solid-state batteries, the exhaust gas is directly passed into the battery. On the premise of ensuring that the battery has a certain processing capacity, the battery needs to have a large volume, and the impurities contained in the exhaust gas will affect the battery reaction. The battery device 12 of this embodiment uses carbon dioxide rich liquid as electrolyte to carry out primary battery reaction, which can ensure efficient carbon dioxide capture, and the volume requirement of the battery device 12 is relatively low, which is conducive to the miniaturization design of the battery device 12.

[0032] Please also read Figure 2 , Figure 2 It is a schematic diagram of the reaction principle of an embodiment of the battery device of the present application.

[0033] In one embodiment, the battery device 12 includes a carbon positive electrode 121 and a metal negative electrode 122 . The carbon positive electrode 121 and the metal negative electrode 122 perform a galvanic cell reaction using a carbon dioxide-rich liquid as an electrolyte to desorb carbon dioxide from the carbon dioxide-rich liquid.

[0034] The material of the metal negative electrode 122 is mainly a metal material with strong reducing property, such as K, Ca, Na, Li, Mg, Al, Zn, etc. Among them, the reducing property of K, Ca, and Na is too strong, and they will react spontaneously with water. It is necessary to design a suitable non-aqueous electrolyte for the negative electrode and set a membrane to separate the positive and negative electrolytes, which is costly and has poor safety and stability. However, the reducing property of metals such as Al and Zn is insufficient, and there are many side reactions when participating in electrode reactions, resulting in low utilization of metal materials. The price of Li is too high, and the shortage of Li resources leads to high cost of Li battery system. Therefore, metal Mg is preferably used as the metal negative electrode 122 of the battery device 12, which has low cost, high stability, and good reversible cycle performance. The positive electrode of the battery device 12 can select an inert electrode such as a carbon positive electrode 121. The carbon positive electrode 121 can use porous carbon nanotubes to increase the reaction rate.

[0035] For example, the absorbent is an amine absorbent, and the material of the metal negative electrode 122 is magnesium. In the absorption device 11, the amine absorbent (RNH2) reacts with carbon dioxide to generate carbamate, and the reaction formula is as follows:

[0036]

[0037] The carbamate solution (i.e., carbon dioxide-rich liquid) enters the battery device 12, and the carbon positive electrode 121 and the metal negative electrode 122 perform a primary battery reaction with the carbon dioxide-rich liquid as the electrolyte to desorb carbon dioxide from the carbon dioxide-rich liquid. The desorbed carbon dioxide combines with metal ions to form oxalate attached to the surface of the carbon positive electrode 121, and the generated elemental carbon is deposited on the surface of the metal negative electrode 122. After the carbamate solution releases carbon dioxide through the reaction, it turns back into an amine absorbent with carbon dioxide absorption capacity. The reaction formula is as follows:

[0038] X (s) →X 2+ (aq) +2e - ;

[0039] 3RNHCOO - +2X 2+ +2e - →2XC2O4+C+2RNH - ;

[0040] RNH - +RNH3 + →2RNH2.

[0041] The overall reaction is as follows:

[0042] 2CO2+X→XC2O4.

[0043] Compared with the high-temperature desorption of rich liquid and the compression and liquefaction of carbon dioxide, this embodiment directly converts the carbamate containing carbon dioxide molecules in the form of complexes in the carbon dioxide rich liquid into salts, and stores carbon dioxide in solid form while achieving rich liquid regeneration, which can reduce energy consumption and help reduce the cost of tail gas purification. In addition, since the Gibbs free energy of salts is lower than that of carbamates, the entire reaction process can proceed spontaneously, not only without external energy input, but the battery device 12 can also release energy to the outside in the form of electrical energy by performing the primary cell reaction, which is very suitable for energy-scarce application scenarios such as ships.

[0044] The battery device 12 can be directly unloaded at the port and transported to a chemical site using carbon dioxide as a raw material for reverse electrolytic cell reaction, using electrical energy to decompose oxalate to generate high-purity carbon dioxide and metal elements. Carbon dioxide can be directly used in chemical industry, and metal elements are precipitated from the metal negative electrode 122, realizing metal regeneration and thus saving costs.

[0045] The reaction formula of the electrolytic cell reaction is as follows:

[0046] XC2O4→2CO2+X.

[0047] In one embodiment, the capture system 10 further includes a circulation tank 13. The output end of the absorption device 11 is connected to the input end of the battery device 12 through the circulation tank 13, and the carbon dioxide-rich liquid is transmitted to the battery device 12 through the circulation tank 13; the output end of the battery device 12 is also connected to the input end of the absorption device 11 through the circulation tank 13, and the carbon dioxide-poor liquid obtained by the primary cell reaction is transmitted from the battery device 12 to the absorption device 11 through the circulation tank 13.

[0048] Specifically, the circulation tank 13 has a partition 131 inside, and the partition 131 divides the inside of the circulation tank 13 into a first chamber 132 and a second chamber 133. The output end of the absorption device 11 is connected to the input end of the battery device 12 through the first chamber 132, and the carbon dioxide-rich liquid output from the absorption device 11 is transmitted to the first chamber 132 inside the circulation tank 13 for storage, and the carbon dioxide-rich liquid in the first chamber 132 is transmitted to the battery device 12 for carbon dioxide desorption. The output end of the battery device 12 is connected to the input end of the absorption device 11 through the second chamber 133. The carbon dioxide-rich liquid is converted back into a carbon dioxide-lean liquid with carbon dioxide absorption capacity through a reaction in the battery device 12, and the carbon dioxide-lean liquid is output from the battery device 12 to the second chamber 133 for storage, and the carbon dioxide-lean liquid in the second chamber 133 is transmitted to the absorption device 11 for the next carbon dioxide capture.

[0049] In one embodiment, the capture system 10 further includes a circulation pump, which is respectively connected to the absorption device 11 and the battery device 12, and is used to pump the carbon dioxide rich liquid to the battery device 12 and / or pump the carbon dioxide lean liquid obtained by the primary cell reaction to the absorption device 11.

[0050] Specifically, the circulation pump may include a first circulation pump 14, which may be disposed between the circulation tank 13 and the input end of the battery device 12, and the first circulation pump 14 is used to pump the carbon dioxide-rich liquid to the battery device 12. The carbon dioxide-rich liquid output from the absorption device 11 is transmitted to the first chamber 132 inside the circulation tank 13 for storage, and under the pumping of the first circulation pump 14, the carbon dioxide-rich liquid in the first chamber 132 is transmitted to the battery device 12 for carbon dioxide desorption.

[0051] The circulation pump may include a second circulation pump 15, which may be disposed between the circulation tank 13 and the input end of the absorption device 11, and is used to pump the carbon dioxide-lean liquid to the absorption device 11. The carbon dioxide-rich liquid is converted into a carbon dioxide-lean liquid having carbon dioxide absorption capacity through a reaction in the battery device 12, and the carbon dioxide-lean liquid is output from the battery device 12 to the second chamber 133 for storage. Under the pumping of the second circulation pump 15, the carbon dioxide-lean liquid in the second chamber 133 is transmitted to the absorption device 11 for the next carbon dioxide capture.

[0052] In one embodiment, the capture system 10 further includes a cooling device 16 , which is connected to the absorption device 11 , and the tail gas is cooled by the cooling device 16 and then input into the absorption device 11 .

[0053] Specifically, the cooling device 16 includes a cooling tower 161 and a cooling flow path 162 connected to the cooling tower 161. The high-temperature exhaust gas containing carbon dioxide is input into the cooling tower 161, and after being cooled and impurities removed by the cooling tower 161, it is input into the absorption device 11. Under the action of the pump, the cooling water in the cooling flow path 162 is sprayed at the upper end of the cooling tower 161 through a nozzle, and contacts and exchanges heat with the high-temperature exhaust gas entering the cooling tower 161 from the lower end, thereby reducing the exhaust gas temperature.

[0054] The absorption device 11 includes an absorption tower 111 and a washing flow path 112 connected to the absorption tower 111. The absorbent reacts with the carbon dioxide in the tail gas in the absorption tower 111 to form a carbon dioxide rich liquid. The absorbent is sprayed at the top of the absorption tower 111 through a nozzle under the action of a pump, and contacts with the tail gas entering from the bottom of the absorption tower 111. The carbon dioxide in the tail gas reacts with the absorbent to form a carbon dioxide rich liquid. The decarbonized tail gas is washed with washing water in the washing flow path 112 and then discharged. The washing water after washing the tail gas is retransmitted back to the absorption tower 111, which can reduce the waste of the absorbent and improve the utilization rate of the absorbent.

[0055] The working principle of the capture system 10 according to the embodiment of the present application is described below.

[0056] The high-temperature tail gas containing carbon dioxide enters the absorption tower 111 after being cooled and impurities removed by the cooling tower 161. The tail gas contacts the absorbent transported by the second circulation pump 15 to the absorption tower 111 for spraying. The carbon dioxide in the tail gas reacts with the absorbent to generate a carbamate solution, i.e., a carbon dioxide-rich liquid. The carbon dioxide-rich liquid enters the electrolytic cell of the battery device 12 through the first circulation pump 14 as an electrolyte for the electrochemical reaction. The metal negative electrode 122 precipitates electrons in the electrolyte environment and becomes metal ions that enter the electrolyte and react with the carbamate solution. The generated oxalate is attached to the surface of the carbon positive electrode 121. The carbon dioxide-poor liquid after desorbing carbon dioxide is returned to the circulation tank 13 under the action of the second circulation pump 15 for the next carbon dioxide capture. The battery device 12 can be directly unloaded at the port and transported to a chemical site using carbon dioxide as a raw material for a reverse electrolytic cell reaction, using electrical energy to promote the decomposition of oxalate to generate high-purity carbon dioxide and metal elements. Carbon dioxide can be directly used in chemical industry, and the metal negative electrode 122 can precipitate metal elements to achieve metal regeneration, thereby saving costs.

[0057] The battery device 12 of the capture system 10 of the embodiment of the present application uses the primary cell reaction to achieve the desorption of carbon dioxide, does not require high temperature reaction conditions, and greatly reduces the energy consumption of the system. In addition, the embodiment of the present application stores carbon dioxide in the form of oxalate with higher density and smaller Gibbs free energy, without the need for compression and liquefaction processes, which greatly reduces the energy consumption and volume of the system; at the same time, the capture system 10 can also discharge to the outside to provide energy for other electrical facilities on the ship. In addition, the transfer and transportation of carbon dioxide in the embodiment of the present application no longer involves low-temperature and high-pressure liquid carbon dioxide. The modular battery device 12 that captures full carbon dioxide can be directly unloaded at the port. After charging and reversible electrolysis to separate carbon dioxide, the battery device 12 can be re-installed on the ship for the next stage of carbon dioxide capture, which greatly simplifies the transfer and transportation process of carbon dioxide.

[0058] The following is an explanation of the carbon dioxide capture method according to the embodiment of the present application. The carbon dioxide capture method according to the embodiment of the present application is based on the capture system 10 explained in the above embodiment.

[0059] See also Figure 3 , Figure 3 It is a flow chart of an embodiment of a method for capturing carbon dioxide of the present application.

[0060] S101: The tail gas is input into the absorption device of the capture system, so that the absorbent reacts with the carbon dioxide in the tail gas in the absorption device to form a carbon dioxide rich liquid.

[0061] In this embodiment, the capture system 10 can be applied to capture carbon dioxide in exhaust gas emitted by ship engines, etc., to achieve exhaust gas purification. The capture system 10 includes an absorption device 11, which is used to receive exhaust gas. The exhaust gas is input into the absorption device 11 of the capture system 10, so that the absorbent reacts with the carbon dioxide in the exhaust gas in the absorption device 11 to form a carbon dioxide rich liquid, which is used in the subsequent desorption of carbon dioxide.

[0062] S102: The carbon dioxide rich liquid is input into the battery device of the capture system. The battery device uses the carbon dioxide rich liquid as an electrolyte to perform a primary cell reaction to desorb carbon dioxide from the carbon dioxide rich liquid.

[0063] In this embodiment, the capture system 10 further includes a battery device 12, which is connected to the absorption device 11 and is used to receive the carbon dioxide rich liquid. The carbon dioxide rich liquid is input into the battery device 12 of the capture system 10, and the battery device 12 uses the carbon dioxide rich liquid as an electrolyte to perform a primary cell reaction to desorb carbon dioxide from the carbon dioxide rich liquid, thereby achieving tail gas purification.

[0064] Through the above-mentioned method, the battery device 12 of this embodiment uses carbon dioxide rich liquid as electrolyte to carry out primary battery reaction, desorbs carbon dioxide from carbon dioxide rich liquid, and then realizes exhaust gas purification. In this way, this embodiment avoids high-temperature desorption and carbon dioxide compression and liquefaction process, can reduce energy consumption, and is conducive to reducing the cost of exhaust gas purification. In addition, the carbon dioxide in the rich liquid is converted into salts through the primary battery reaction, and the carbon dioxide is stored in a solid form, which can reduce the difficulty of transfer and transportation, and is conducive to reducing the cost of exhaust gas purification. In addition, for solid-state batteries, the exhaust gas is directly passed into the battery. On the premise of ensuring that the battery has a certain processing capacity, the battery needs to have a large volume, and the impurities contained in the exhaust gas will affect the battery reaction. The battery device 12 of this embodiment uses carbon dioxide rich liquid as electrolyte to carry out primary battery reaction, which can ensure efficient carbon dioxide capture, and the volume requirement of the battery device 12 is relatively low, which is conducive to the miniaturization design of the battery device 12.

[0065] See also Figure 4 , Figure 4 It is a flow chart of another embodiment of the carbon dioxide capture method of the present application.

[0066] S201: The exhaust gas is input into the cooling device of the capture system for cooling.

[0067] In this embodiment, the tail gas is input into the cooling device 16 for cooling. Specifically, the cooling device 16 includes a cooling tower 161 and a cooling flow path 162 connected to the cooling tower 161. The high-temperature tail gas containing carbon dioxide is input into the cooling tower 161, and after being cooled and impurities removed by the cooling tower 161, it is input into the absorption device 11. Under the action of the pump, the cooling water in the cooling flow path 162 is sprayed at the upper end of the cooling tower 161 through a nozzle, and contacts and exchanges heat with the high-temperature tail gas entering the cooling tower 161 from the lower end, thereby reducing the tail gas temperature.

[0068] S202: The tail gas is input into the absorption device of the capture system, so that the absorbent reacts with the carbon dioxide in the tail gas to obtain a carbamate solution.

[0069] In this embodiment, the absorbent is an amine absorbent. After the tail gas is cooled by the cooling device 16, the tail gas is input into the absorption device 11 of the capture system 10, so that the absorbent reacts with the carbon dioxide in the tail gas to obtain a carbamate solution, i.e., a carbon dioxide rich liquid, which is used in the subsequent desorption of carbon dioxide.

[0070] Specifically, the absorption device 11 includes an absorption tower 111 and a washing flow path 112 connected to the absorption tower 111. The absorbent reacts with the carbon dioxide in the tail gas in the absorption tower 111 to form a carbon dioxide rich liquid. The absorbent is sprayed at the top of the absorption tower 111 through a nozzle under the action of a pump, and contacts the tail gas entering from the bottom of the absorption tower 111. The carbon dioxide in the tail gas reacts with the absorbent to form a carbon dioxide rich liquid. The decarbonized tail gas is washed with washing water in the washing flow path 112 and then discharged. The washing water after washing the tail gas is retransmitted back to the absorption tower 111, which can reduce the waste of absorbent and improve the utilization rate of the absorbent.

[0071] S203: The carbamate solution is input into the battery device of the capture system. The battery device uses the carbamate solution as an electrolyte to perform a primary battery reaction. The generated magnesium oxalate adheres to the surface of the carbon positive electrode of the battery device.

[0072] In this embodiment, the material of the metal negative electrode 122 of the battery device 12 is magnesium. The material of the metal negative electrode 122 is mainly a metal material with strong reducing property, such as K, Ca, Na, Li, Mg, Al, Zn, etc. Among them, the reducing property of K, Ca, and Na is too strong, and they will react spontaneously with water. It is necessary to design a suitable non-aqueous electrolyte for the negative electrode and to set a membrane to separate the positive and negative electrode electrolytes, which is costly and has poor safety and stability. However, the reducing property of metals such as Al and Zn is insufficient, and there are many side reactions when participating in the electrode reaction, resulting in low utilization of metal materials. The price of Li is too high, and the shortage of Li resources leads to high cost of Li battery system. Therefore, metal Mg is preferably used as the metal negative electrode 122 of the battery device 12, which has low cost, high stability, and good reversible cycle performance. The positive electrode of the battery device 12 can select an inert electrode such as a carbon positive electrode 121. The carbon positive electrode 121 can use porous carbon nanotubes to increase the reaction rate.

[0073] In this embodiment, the carbamate solution is input into the battery device 12 of the capture system 10. The battery device 12 uses the carbamate solution as the electrolyte to perform a primary cell reaction, and the generated magnesium oxalate is attached to the surface of the carbon positive electrode 121 of the battery device 12. The generated elemental carbon is deposited on the surface of the metal negative electrode 122. After the carbamate solution releases carbon dioxide through the reaction, it is transformed back into an amine absorbent with carbon dioxide absorption capacity, that is, a carbon dioxide-lean liquid. The carbon dioxide-lean liquid is returned to the absorption device 11 and is used again to capture carbon dioxide in the exhaust gas.

[0074] S204: performing an electrolytic cell reaction on the battery device to obtain carbon dioxide and metal elements.

[0075] In this embodiment, the battery device 12 can be directly unloaded at the port and transported to a chemical site using carbon dioxide as a raw material for a reverse electrolytic cell reaction, that is, the battery device 12 is subjected to an electrolytic cell reaction, and electric energy is used to promote the decomposition of oxalate to generate high-purity carbon dioxide and metal elements, and the metal elements are the same metal as the metal negative electrode 122 of the battery device 12. Carbon dioxide can be directly used in chemical industry, and the metal negative electrode 122 precipitates metal elements, realizing metal regeneration and thus saving costs.

[0076] In this embodiment, the transfer and transportation of carbon dioxide no longer involves low-temperature and high-pressure liquid carbon dioxide. The modular battery device 12 that has captured a lot of carbon dioxide can be directly unloaded at the port. After charging and reversibly electrolyzing the carbon dioxide, the battery device 12 can be reinstalled on the ship for the next stage of carbon dioxide capture, which greatly simplifies the transfer and transportation process of carbon dioxide.

[0077] In summary, the present application provides a carbon dioxide capture system and capture method. The absorbent of the present application reacts with the carbon dioxide in the exhaust gas in the absorption device to form a carbon dioxide rich liquid, and the battery device uses the carbon dioxide rich liquid as the electrolyte to perform a primary battery reaction to desorb carbon dioxide from the carbon dioxide rich liquid to achieve exhaust gas purification. The present application avoids high-temperature desorption and carbon dioxide compression and liquefaction processes, can reduce energy consumption, and is beneficial to reducing the cost of exhaust gas purification. In addition, the carbon dioxide in the rich liquid is converted into salts through the primary battery reaction, and the carbon dioxide is stored in a solid form, which can reduce the difficulty of transfer and transportation, and is beneficial to reducing the cost of exhaust gas purification. In addition, the battery device of the present application includes a carbon positive electrode and a metal negative electrode, and uses the carbon dioxide rich liquid as the electrolyte to perform a primary battery reaction, which can ensure efficient carbon dioxide capture and is beneficial to the miniaturized design of the battery device.

[0078] The carbon dioxide capture system and capture method provided by the present application are introduced in detail above. Specific examples are used in this article to illustrate the principles and implementation methods of the present application. The description of the above embodiments is only used to help understand the method of the present application and its core idea. At the same time, for those skilled in the art, according to the idea of ​​the present application, there will be changes in the specific implementation method and application scope. In summary, the content of this specification should not be understood as a limitation on the present application.

Claims

1. A carbon dioxide capture system, characterized in that: The capture system comprises: an absorber in which an absorbent reacts with carbon dioxide in the tail gas to form a carbon dioxide-rich liquid; and A battery device is connected to the absorption device, and is used to receive the carbon dioxide rich liquid; the battery device includes a carbon positive electrode and a metal negative electrode, and is configured to perform a galvanic cell reaction using the carbon dioxide rich liquid as an electrolyte to desorb carbon dioxide from the carbon dioxide rich liquid.

2. The capture system according to claim 1, characterized in that: The absorbent is an amine absorbent, and the material of the metal negative electrode is magnesium.

3. The capture system according to claim 1 or 2, characterized in that: The capture system also includes: A circulation tank, wherein the output end of the absorption device is connected to the input end of the battery device through the circulation tank, the carbon dioxide rich liquid is transmitted to the battery device through the circulation tank, and the output end of the battery device is connected to the input end of the absorption device through the circulation tank, and the carbon dioxide lean liquid obtained by the primary cell reaction is transmitted from the battery device to the absorption device through the circulation tank.

4. The capture system according to claim 3, characterized in that: The circulation tank has a partition inside, which divides the inside of the circulation tank into a first chamber and a second chamber. The output end of the absorption device is connected to the input end of the battery device through the first chamber, and the output end of the battery device is connected to the input end of the absorption device through the second chamber.

5. The capture system according to claim 3, characterized in that: The capture system also includes: The first circulation pump is arranged between the circulation tank and the input end of the battery device, and is used for pumping the carbon dioxide rich liquid to the battery device.

6. The capture system according to claim 3, characterized in that: The capture system also includes: The second circulation pump is arranged between the circulation tank and the input end of the absorption device, and the second circulation pump is used to pump the carbon dioxide lean liquid to the absorption device.

7. The capture system according to claim 1 or 2, characterized in that: The capture system also includes: A circulation pump is connected to the absorption device and the battery device respectively, and is used to pump the carbon dioxide rich liquid to the battery device and / or pump the carbon dioxide lean liquid obtained by the primary cell reaction to the absorption device.

8. The capture system according to claim 1 or 2, characterized in that: The capture system also includes: A cooling device is connected to the absorption device, and the tail gas is cooled by the cooling device and then input into the absorption device.

9. A method for capturing carbon dioxide, characterized in that: The capture method is based on the capture system according to any one of claims 1 to 8, and the capture method comprises: Inputting the tail gas into the absorption device of the capture system, so that the absorbent reacts with the carbon dioxide in the tail gas in the absorption device to form a carbon dioxide-rich liquid; The carbon dioxide rich liquid is input into the battery device of the capture system, and the battery device uses the carbon dioxide rich liquid as an electrolyte to perform a galvanic cell reaction to desorb carbon dioxide from the carbon dioxide rich liquid.

10. The capture method according to claim 9, characterized in that: The absorbent is an amine absorbent; The step of reacting the absorbent with the carbon dioxide in the tail gas in the absorption device to form a carbon dioxide-rich liquid comprises: The absorbent reacts with the carbon dioxide in the tail gas to obtain a carbamate solution.

11. The capture method according to claim 10, characterized in that: The material of the metal negative electrode of the battery device is magnesium; The steps of the battery device using the carbon dioxide-rich liquid as the electrolyte to perform a primary battery reaction include: The carbamate solution is used as an electrolyte to carry out a primary cell reaction, and the generated magnesium oxalate adheres to the surface of the carbon positive electrode of the battery device.

12. The capture method according to claim 9, characterized in that: After the step of using the carbon dioxide-rich liquid as the electrolyte to perform a primary cell reaction, the battery device comprises: The battery device is subjected to an electrolytic cell reaction to obtain carbon dioxide and a metal element, wherein the metal element is the same metal as the metal negative electrode of the battery device.

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