Carbon dioxide capture absorbent including evaporation inhibitor

Abstract

A carbon dioxide absorbent including an evaporation inhibitor according to the present invention relates to an absorbent used in a wet carbon dioxide capture process. The absorbent including an evaporation inhibitor can effectively absorb carbon dioxide and suppress evaporation to reduce regeneration energy consumption due to latent heat of water consumed in a removal process, thereby increasing energy efficiency.

Description

Carbon dioxide capture and absorbent including evaporation inhibitor

[0001] Cross-citation with related applications

[0002] This application claims the benefit of priority from Korean Patent Application No. 10-2024-0100242, filed July 25, 2024, the entire contents of which are incorporated herein by reference.

[0003] Technology field

[0004] The present invention relates to a carbon dioxide absorbent, and more particularly, to a carbon dioxide absorbent that reduces heat consumed in the carbon dioxide removal process during a carbon dioxide wet absorption process through an evaporation inhibitor.

[0005] The material described in this section merely provides background information for the present invention and does not constitute prior art.

[0006] Gases emitted from thermal power plants and petrochemical industry NCCs contain carbon dioxide. Due to global warming concerns, numerous technologies are being developed to reduce carbon dioxide emissions. Carbon dioxide capture (CO2 capture) is a method that directly reduces CO2 emissions. It separates CO2 from exhaust gas and reduces CO2 emissions.

[0007] Many technologies are used for carbon dioxide capture, including absorption, adsorption, and membrane separation. Absorption is the most widely used due to its high efficiency, stability, and versatility. Absorption utilizes basic substances or amines. When amines are used, amines such as MEA, MDEA, AMP, PZ, and DEA are used alone or in combination.

[0008] In the absorption method, carbon dioxide in exhaust gas is reduced by absorbing it and capturing it within the absorbent through a reaction between the amine and carbon dioxide contained in the absorbent. The absorbent containing carbon dioxide is then heated to remove the carbon dioxide and regenerated. Furthermore, high-purity carbon dioxide is produced during the regeneration process.

[0009] Among the operating costs of the absorption process, the heat consumed during the regeneration process accounts for the largest portion, and therefore, reducing the amount of renewable energy used for regeneration is very important from an economic perspective for the absorption process.

[0010] Research is being conducted to reduce the water content, which has a large specific heat and heat of vaporization, or to replace water with an organic solvent as a way to lower renewable energy. However, when reducing the water content or replacing water with an organic solvent, the problem of reduced carbon dioxide absorption capacity arises.

[0011] [Prior Art Literature]

[0012] [Patent Document]

[0013] Korean Patent Publication No. 10-2011-0099466A (September 8, 2011)

[0014] The present invention was derived to solve the above-mentioned problem, and the purpose of the present invention is to provide an absorbent that reduces heat consumption by suppressing evaporation of water during the carbon dioxide removal process through improvement of the carbon dioxide absorbent.

[0015] To achieve the above object, the present invention provides a carbon dioxide absorbent comprising a triamine, an ether, water, and an evaporation inhibitor, wherein the evaporation inhibitor is a polyol.

[0016] Another aspect of the present invention for achieving the above object is to provide a carbon dioxide capture method, characterized by including a first step of capturing carbon dioxide from a mixed gas containing carbon dioxide using the carbon dioxide absorbent; and a second step of removing carbon dioxide from the carbon dioxide absorbent in which carbon dioxide has been absorbed.

[0017] The carbon dioxide absorbent including the evaporation inhibitor according to the present invention, unlike the carbon dioxide absorbent of a conventional wet carbon dioxide capture process, suppresses the evaporation of water within the absorbent, thereby reducing the heat consumed in the carbon dioxide removal process and thus reducing the process operating cost.

[0018] In addition, evaporation inhibitors can reduce environmental pollution and reduce the cost of reducing it by suppressing the evaporation of amine substances and thus the emission of hazardous substances.

[0019] Figure 1 is a schematic diagram illustrating a carbon dioxide capture process.

[0020] Figure 2 is a schematic diagram of a device for measuring carbon dioxide absorption capacity according to an embodiment of the invention.

[0021] The present invention will be described in more detail. Unless otherwise defined, the technical and scientific terms used herein have the meanings commonly understood by those of ordinary skill in the art to which this invention pertains. In the following description, descriptions of well-known functions and configurations that may unnecessarily obscure the gist of the present invention will be omitted.

[0022] The singular form used in the present invention may be intended to include the plural form as well, unless the context specifically indicates otherwise.

[0023] The term "includes" as described in the present invention is an open-ended description having an equivalent meaning to expressions such as "comprises," "contains," "has," or "characterizes," and does not exclude additional elements, materials, or processes not listed.

[0024] The present invention is a carbon dioxide absorbent comprising triamine, ether, water and an evaporation inhibitor, characterized in that the evaporation inhibitor is a polyol.

[0025] The above carbon dioxide absorbent is a material used in a carbon dioxide wet capture process, and by including the evaporation inhibitor, the vapor pressure of the absorbent is lowered during the carbon dioxide removal process. The absorbent with the lowered vapor pressure is prevented from evaporating through heating in the regeneration tower, thereby reducing the outflow of the absorbent and reducing the heat of evaporation, thereby reducing heat consumption in the regeneration tower, ultimately reducing process costs.

[0026] The above evaporation inhibitor is a polyol, more preferably ethylene glycol or glycerol.

[0027] The above triamine is preferably a compound represented by the following [chemical formula 1].

[0028] [Chemical Formula 1]

[0029]

[0030] In the above formula, n and m are each independently an integer between 1 and 10, and preferably an integer between 2 and 4.

[0031] Also R 1 Inland R 5 are each independently hydrogen or a C1-C10 alkyl group, preferably hydrogen or a C1-C5 alkyl group.

[0032] The "alkyl group" described in the present invention means a monovalent straight-chain or branched saturated hydrocarbon radical composed only of carbon and hydrogen atoms, and examples of such alkyl radicals include, but are not limited to, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, t-butyl, pentyl, hexyl, octyl, nonyl, and the like.

[0033] The above triamine more preferably includes at least one selected from the group consisting of 2,2'-iminobis(N,N-dimethylethylamine), 2,2'-iminobis(N,N-diethylethylamine), 3,3'-iminobis(N,N-dimethylpropylamine), 3,3'-iminobis(N,N-diethylpropylamine), but is not limited thereto.

[0034] The above ether is preferably a compound represented by the following [chemical formula 2].

[0035] [Chemical Formula 2]

[0036]

[0037] In the above formula, o is an integer between 1 and 10, and preferably an integer between 2 and 4.

[0038] R 6 and R 7 are each independently hydrogen or a C1-C10 alkyl group, preferably a C1-C3 alkyl group.

[0039] The above ether more preferably includes at least one selected from the group consisting of tetraethylene glycol dimethyl ether, tetraethylene glycol diethyl ether, tetraethylene glycol dipropylene ether, tetraethylene glycol methylethyl ether, tetraethylene glycol methylpropyl ether, tetraethylene glycol ethylpropyl ether, triethylene glycol dimethyl ether, triethylene glycol diethyl ether, triethylene glycol dipropylene ether, triethylene glycol methylethyl ether, triethylene glycol methylpropyl ether, and triethylene glycol ethylpropyl ether, but is not limited thereto.

[0040] In the present invention, the evaporation inhibitor is included in an amount of 5 to 50 wt%, preferably 10 to 40 wt%, of the total amount of the carbon dioxide absorbent. If the amount of the evaporation inhibitor is less than 5 wt%, the evaporation inhibition effect of the water within the absorbent becomes poor, and if it exceeds 50 wt%, there is a problem of poor carbon dioxide absorption performance.

[0041] In the present invention, triamine is included in an amount of 20 to 50 wt%, preferably 25 to 45 wt%, of the total amount of the carbon dioxide absorbent. If the amount of triamine is less than 20 wt%, the carbon dioxide absorption effect is small, and if it exceeds 50 wt%, it causes a decrease in absorption performance and an increase in the viscosity of the absorbent.

[0042] In the present invention, ether is included in an amount of more than 0% by weight and less than or equal to 20% by weight, preferably 2% to 15% by weight, of the total amount of the carbon dioxide absorbent. If ether is not present, there is a problem of a low absorption rate, and if the amount of ether exceeds 20% by weight, there is a problem of a reduced absorption capacity.

[0043] In the present invention, water comprises 20 to 50 wt% of the total amount of the carbon dioxide absorbent. If the amount of water is less than 20 wt%, the viscosity of the absorbent solution increases, and if it exceeds 50 wt%, the viscosity of the absorbent decreases, but the carbon dioxide absorption capacity decreases.

[0044] The present invention provides, as one embodiment, a method for capturing carbon dioxide, the method comprising: a first step of capturing carbon dioxide from a mixed gas containing carbon dioxide using the carbon dioxide absorbent; and a second step of removing carbon dioxide from the carbon dioxide absorbent in which carbon dioxide has been absorbed.

[0045] More specifically, carbon dioxide removal according to the present invention can be accomplished using the device of FIG. 1. The removal method is divided into two stages: 1) a first stage in which carbon dioxide is absorbed into an absorbent in a gas containing carbon dioxide, and 2) a second stage in which the absorbent containing carbon dioxide is heated to remove carbon dioxide and the absorbent is regenerated.

[0046] In the first stage, flue gas (101) is injected into the bottom of the absorption tower (100) and discharged to the top. Absorbent (103) is injected into the top of the absorption tower. As the flue gas passes through the absorption tower, it comes into contact with the absorbent injected from the top and flowing down, and in this process, carbon dioxide is absorbed by the absorbent. The flue gas (104) from which the absorbent has been removed is discharged to the top of the absorption tower. The absorbent (102) containing carbon dioxide is discharged to the bottom of the absorption tower, heated through a heat exchanger (220), and then the heated absorbent (201) is injected to the top of the regeneration tower.

[0047] In the second stage, the absorbent (201) containing carbon dioxide injected into the upper part of the regeneration tower descends to the lower part of the regeneration tower, and the lower part of the regeneration tower is heated through a reboiler (210). Due to the heating, the solubility of carbon dioxide in the absorbent decreases, and the carbon dioxide is removed. The removed carbon dioxide (205) is discharged in a gaseous state through the upper part of the regeneration tower. The absorbent (202) regenerated by removing carbon dioxide is cooled through a heat exchanger (220), and then injected back into the absorption tower (100).

[0048] In the present invention, the temperature of the first step is preferably in the range of 30 to 60°C. If the temperature is below 30°C, there is a problem in that cooling with cooling water is difficult in the summer, and if the temperature exceeds 60°C, the solubility of carbon dioxide decreases, resulting in a decrease in absorption performance.

[0049] In the present invention, the temperature of the second step is preferably in the range of 80 to 150°C. If the absorption temperature is less than 80°C, the solubility of carbon dioxide does not decrease significantly, resulting in low stripping efficiency. If the temperature exceeds 150°C, solvent leakage may occur due to thermal denaturation and evaporation of the solvent.

[0050] In the present invention, the pressure of the second step is preferably 10 atm or less. If the pressure exceeds 10 atm, the temperature for carbon dioxide removal increases, causing thermal denaturation of the solvent. In addition, high-pressure steam or a heat source is required, making it economically inefficient.

[0051] In the present invention, the evaporation inhibitor reduces the amount of heat consumed in the reboiler (210) of the second stage. The heat injected from the reboiler is used to heat the absorbent that has captured carbon dioxide. The heated absorbent emits carbon dioxide due to the difference in carbon dioxide solubility according to temperature change, and the emitted carbon dioxide is removed from the top of the regeneration tower. In addition, the heated absorbent evaporates according to the vapor pressure of the absorbent and is emitted together with the carbon dioxide. This causes the outflow of the absorbent, and the vaporization heat consumed when the absorbent evaporates causes additional heat consumption. The evaporation inhibitor proposed in the present invention is a substance that lowers the vapor pressure of the absorbent, and the evaporation of the absorbent with the lowered vapor pressure is suppressed through heating in the regeneration tower. This reduces the outflow of the absorbent, reduces the heat of vaporization, and thus reduces the heat consumption in the regeneration tower.

[0052] Therefore, the heat used in the regeneration tower can be reduced by using a carbon dioxide absorbent including an evaporation inhibitor, and the problem caused by absorbent leakage can be solved.

[0053]

[0054] Hereinafter, the present invention will be described in more detail through examples. These examples are intended solely to illustrate the present invention, and it will be apparent to those skilled in the art that the scope of the present invention is not limited by these examples.

[0055]

[0056] [Example 1]

[0057] An absorbent was prepared by mixing 45 wt% of 3,3'-ibininobis(N,N-dimethylpropylamine) (CAS No. 6711-48-4) as a triamine, 5 wt% of tetraethylene glycol dimethyl ether, 30 wt% of water, and 20 wt% of glycerol as an evaporation inhibitor.

[0058]

[0059] [Example 2]

[0060] An absorbent was prepared by mixing 30 wt% of 3,3'-ibininobis(N,N-dimethylpropylamine) (CAS No. 6711-48-4) as a triamine, 5 wt% of tetraethylene glycol dimethyl ether, 35 wt% of water, and 30 wt% of glycerol as an evaporation inhibitor.

[0061]

[0062] [Example 3]

[0063] An absorbent was prepared in the same manner as in Example 1, except that the evaporation inhibitor was changed to ethylene glycol.

[0064]

[0065] [Comparative Example 1]

[0066] An absorbent was prepared in the same manner as in Example 1, except that the evaporation inhibitor was changed to 1,3-propanediol.

[0067]

[0068] [Comparative Example 2]

[0069] An absorbent was prepared in the same manner as in Example 1, except that the evaporation inhibitor was changed to 1,4-butanediol.

[0070]

[0071] [Comparative Example 3]

[0072] An absorbent was prepared by mixing 45 wt% of 3,3'-ibininobis(N,N-dimethylpropylamine) (CAS No. 6711-48-4) as triamine, 0 wt% of ether, and 55 wt% of water.

[0073]

[0074] [Comparative Example 4]

[0075] An absorbent was prepared by mixing 40 wt% of 3,3'-ibininobis(N,N-dimethylpropylamine) (CAS No. 6711-48-4) as triamine, 20 wt% of tetraethylene glycol dimethyl ether, and 40 wt% of water.

[0076]

[0077] [Comparative Example 5]

[0078] An absorbent was prepared by mixing 45 wt% of 3,3'-ibininobis(N,N-dimethylpropylamine) (CAS No. 6711-48-4) as triamine, 5 wt% of tetraethylene glycol dimethyl ether, 30 wt% of water, and 20 wt% of 1,6-hexanediol.

[0079]

[0080] Vapor pressure calculation

[0081] The evaporation suppression effect of the absorbent, including the evaporation suppressor proposed in the present invention, can be confirmed by measuring the vapor pressure of the absorbent. In this study, the vapor pressure of the absorbent was calculated using a commercial simulator, Aspen Plus. The thermodynamic parameters used in the process simulator were derived from both built-in values ​​and experimentally obtained values. The vapor pressures of different absorbents were compared during the stripping process, depending on their composition.

[0082]

[0083] Absorbent vapor pressure (kPa, 90℃) Example 154.2 Example 254.5 Example 349.8 Comparative Example 156.6 Comparative Example 261.3 Comparative Example 365.2 Comparative Example 463.8 Comparative Example 563.4

[0084] Energy consumption during the carbon dioxide removal process can be indirectly determined by comparing vapor pressures. Comparing Comparative Examples 3 and 4 with Examples 1 and 3 confirmed that the carbon dioxide absorbent containing the evaporation inhibitor had a lower vapor pressure, resulting in less water evaporation.

[0085] Through comparison of Comparative Examples 1, 2 and 5 using 1,3-propanediol, 1,4-butanediol and 1,6-hexanediol, which have a similar structure to the evaporation inhibitor of the present invention, and Examples 1 to 3, it was confirmed that when 1,3-propanediol, 1,4-butanediol and 1,6-hexanediol were used, the vapor pressure decreased, but the degree was smaller than that of ethylene glycol and glycerol, and that 1,4-butanediol and 1,6-hexanediol had a minimal evaporation inhibition effect.

[0086]

[0087] Measurement of carbon dioxide absorption capacity

[0088] Carbon dioxide absorption capacity was measured using the device of Fig. 2. 50 ml of a pre-prepared absorbent was injected into a device maintained under vacuum using a vacuum pump. CO2 was injected through an MFC, and the temperature of the device was adjusted to a constant temperature T using a circulator injected with silicone oil. The device was maintained for more than 1 hour to allow evaporation of the absorbent, and when the pressure was maintained constant while the temperature was maintained at T, nitrogen was injected so that the internal pressure of the device became the target pressure P0(T) and recorded. The target pressure P0(T) was set to 1 atm.

[0089]

[0090] Carbon dioxide is injected at a constant rate through an MFC into a device where the temperature is T and the pressure is maintained at P0(T). After the injection for a certain period of time, the pressure in the device is maintained constant, and the pressure (P1(T)) of the device is recorded. This is used to calculate the carbon dioxide partial pressure, carbon dioxide absorption, and absorption capacity. The temperature unit is ℃, and the pressure unit is kPa.

[0091]

[0092] At this time, the partial pressure of carbon dioxide and the amount of carbon dioxide absorbed are calculated as follows:

[0093]

[0094] Partial pressure of carbon dioxide (P) at temperature T CO2 (T))

[0095] P CO2 (T) = P1(T) - P0(T)

[0096]

[0097] T: Equilibrium temperature (℃)

[0098] P CO2 (T): partial pressure of carbon dioxide (kPa) at temperature T

[0099] P1(T): Equilibrium pressure (kPa) at temperature T after carbon dioxide injection

[0100] P0(T): Equilibrium pressure (kPa) at temperature T after carbon dioxide injection

[0101]

[0102] Liquid CO2 absorption (M CO2,l )

[0103] M CO2,l = M CO2,overall - M CO2,v

[0104] M CO2,overall = F CO2,overall * t - V V * ρ CO2,v

[0105] V V = V equip - V abs

[0106]

[0107] M CO2,l : Liquid carbon dioxide absorption (g)

[0108] M CO2,overall : Amount of carbon dioxide injected into the device (g)

[0109] M CO2,v : Amount of atmospheric carbon dioxide (g)

[0110] F CO2,overall : Carbon dioxide injection rate (g / min)

[0111] t: Carbon dioxide injection time (min)

[0112] V V : Gas volume (ml)

[0113] ρ CO2,v : Temperature T, partial pressure of carbon dioxide P CO2 Carbon dioxide density (g / ml) in (T)

[0114] V equip : Internal volume of the device (ml)

[0115] V abs : Volume of injected absorbent (ml)

[0116]

[0117] Carbon dioxide absorption capacity of the absorbent (α(T))

[0118] α(T) = M CO2,l / M abs

[0119] α(T): Temperature T, carbon dioxide absorption capacity of the absorbent (g / kg solvent)

[0120] M abs : Absorbent injection amount (kg)

[0121]

[0122] This process is called adsorption condition (T abs ), detachment condition (T des ) is repeated, and the circulating absorption capacity is calculated as the difference between the two values.

[0123]

[0124] Circulating absorption capacity (Δα)

[0125] Δα = α(T abs, P CO2 (T abs )) - α(T des, P CO2 (T des ))

[0126] Δα: Carbon dioxide circulation absorption capacity of the absorbent (g / kg solvent)

[0127] α(T abs ) : Amount of carbon dioxide captured under adsorption conditions (g / kg solvent)

[0128] P CO2 (T abs ) : Carbon dioxide partial pressure (kPa) under adsorption conditions

[0129] α(T des ) : Amount of carbon dioxide captured under desorption conditions (g / kg solvent)

[0130] P CO2 (T des ) : Carbon dioxide partial pressure (kPa) under desorption conditions

[0131]

[0132] Circulating absorption capacity (g / kg) @Example 185.4Example 2102.0Example 380.8Comparative example 144.0Comparative example 379.1Comparative example 479.5

[0133]

[0134] Table 2 shows the results of measuring the cyclic absorption capacity under adsorption conditions (40°C, 10 kPa) and desorption conditions (120°C, 101.325 kPa). Examples 1-3 are absorbents containing ethylene glycol or glycerol as an evaporation inhibitor, while Comparative Examples 1 and 2 contained glycol-based substances, and Comparative Examples 3 and 4 are absorbents that do not contain glycol-based substances or glycerol. When comparing Examples 1 and 3 with Comparative Examples 1 and 2, the cyclic absorption capacities did not differ significantly, and even when an evaporation inhibitor was included, there was no significant change in the cyclic absorption capacity, confirming that the performance was maintained even when an evaporation inhibitor was added.

[0135] Through Example 2, it was confirmed that when the ratio of absorbent was adjusted by adding an evaporation inhibitor, the absorption capacity increased due to the addition of an evaporation inhibitor, and the absorbent performance increased compared to the existing absorbent without an evaporation inhibitor.

[0136] In Comparative Example 1, the cyclic absorption capacity was significantly reduced. This confirmed that the addition of glycol-based substances did not all result in an increase in the cyclic absorption capacity, and that only ethylene glycol and glycerol did not reduce the performance of the carbon dioxide absorbent.

[0137] As described above, the present invention has been described through specific matters and limited examples and comparative examples, but these are provided only to help a more general understanding of the present invention, and the present invention is not limited to the above examples, and those skilled in the art to which the present invention pertains can make various modifications and variations based on this description.

[0138] Therefore, the idea of ​​the present invention should not be limited to the described embodiments, and all things that are equivalent or equivalent to the following claims as well as the claims are considered to fall within the scope of the idea of ​​the present invention.

[0139]

[0140] [Explanation of symbols]

[0141] 100: Absorption tower

[0142] 101: Exhaust gas

[0143] 102: Absorbent containing carbon dioxide (discharged to the bottom of the absorption tower)

[0144] 103: Absorbent (injected into the top of the absorption tower)

[0145] 104: Flue gas with absorbent removed

[0146] 200: Regeneration Tower

[0147] 201: Absorbent containing carbon dioxide (injected into the top of the regeneration tower)

[0148] 202: Regenerated absorbent

[0149] 203: Absorbent injected into the reboiler for heating

[0150] 204: Absorbent heated by reboiler

[0151] 205: Carbon dioxide (the removed carbon dioxide is discharged through the top of the regeneration tower in a gaseous state)

[0152] 210: Reboiler

[0153] 220: Heat exchanger

Claims

1. A carbon dioxide absorbent containing triamine, ether, water and an evaporation inhibitor, A carbon dioxide absorbent, characterized in that the above evaporation inhibitor is a polyol.

2. A carbon dioxide absorbent according to claim 1, characterized in that the evaporation inhibitor is ethylene glycol or glycerol.

3. A carbon dioxide absorbent according to claim 1, wherein the triamine is represented by the following [chemical formula 1]. [Chemical Formula 1] (In the above formula, n and m are each independently integers between 1 and 10, R 1 Inland R 5 are each independently hydrogen or a C1-C10 alkyl group) 4. A carbon dioxide absorbent, characterized in that in the third paragraph, the triamine comprises at least one selected from the group consisting of 2,2'-iminobis(N,N-dimethylethylamine), 2,2'-iminobis(N,N-diethylethylamine), 3,3'-iminobis(N,N-dimethylpropylamine), and 3,3'-iminobis(N,N-diethylpropylamine).

5. A carbon dioxide absorbent according to claim 1, characterized in that the ether is represented by the following [chemical formula 2]. [Chemical Formula 2] (In the above formula, o is an integer between 1 and 10, R 6 and R 7 are each independently hydrogen or a C1-C10 alkyl group) 6. A carbon dioxide absorbent according to claim 5, characterized in that the ether comprises at least one selected from the group consisting of tetraethylene glycol dimethyl ether, tetraethylene glycol diethyl ether, tetraethylene glycol dipropylene ether, tetraethylene glycol methylethyl ether, tetraethylene glycol methylpropyl ether, tetraethylene glycol ethylpropyl ether, triethylene glycol dimethyl ether, triethylene glycol diethyl ether, triethylene glycol dipropylene ether, triethylene glycol methylethyl ether, triethylene glycol methylpropyl ether, and triethylene glycol ethylpropyl ether.

7. A carbon dioxide absorbent according to claim 1, characterized in that the carbon dioxide absorbent contains 5 to 50 wt% of an evaporation inhibitor.

8. A carbon dioxide absorbent according to claim 1, characterized in that the carbon dioxide absorbent contains 20 to 50 wt% of triamine.

9. A carbon dioxide absorbent according to claim 1, characterized in that the carbon dioxide absorbent contains ether in an amount of more than 0% by weight and less than or equal to 20% by weight.

10. A carbon dioxide absorbent according to claim 1, characterized in that the carbon dioxide absorbent contains 20 to 50 wt% of water.

11. A first step of capturing carbon dioxide from a mixed gas containing carbon dioxide using a carbon dioxide absorbent according to paragraph 1; and The second step is to remove carbon dioxide from the carbon dioxide absorbent in which carbon dioxide has been absorbed; A method for capturing carbon dioxide, characterized in that it comprises:

12. A carbon dioxide capture method according to claim 11, characterized in that the temperature of the first step is between 30 degrees and 60 degrees.

13. A carbon dioxide capture method according to claim 12, characterized in that the temperature of the second step is between 80 degrees and 150 degrees.

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