Absorption liquid for capturing carbon dioxide with low temperature desorption and high cycle stability, and preparation method and application thereof

Abstract

The application discloses a kind of low-temperature desorption and high cycle stability absorption liquid for capturing carbon dioxide and its preparation method and application, it is related to gas separation and purification technical field, including main absorption component, auxiliary agent and solvent;Main absorption component is at least one of N-ethyl piperazine, 1-methyl piperazine and N-hydroxyethyl piperazine;Solvent is at least one of 1-dimethylamino-2-propanol, diethylaminoethanol and N,N-dimethylethanolamine;Auxiliary agent is selected from composite antioxidant and desorption promoter.The multi-component synergistic design of the application makes the system maintain high capture efficiency under the premise, with excellent low-temperature desorption performance and long-term cycle stability, ensures that amine liquid long-term stable and efficient operation, reduces the operating cost caused by amine liquid degradation, equipment corrosion and high energy consumption, with good application prospect.

Description

Technical Field

[0001] This invention relates to the field of gas separation and purification technology, and more specifically, to an absorbent liquid for capturing carbon dioxide with low-temperature desorption and high cycle stability, its preparation method, and its application. Background Technology

[0002] With the continuous rise in global greenhouse gas emissions, the massive emission of carbon dioxide (CO2) has been widely recognized as one of the main causes of climate change and the greenhouse effect. Against this backdrop, carbon capture, utilization, and storage (CCUS) technology has become a key technological pathway for achieving emission reduction targets in various countries. Among these technologies, chemical absorption has become the mainstream technology for industrial-scale CO2 capture due to its high maturity and excellent capture efficiency. Traditional chemical absorption methods mainly use amine solutions, typically monoethanolamine (MEA) aqueous solutions. These absorbents react reversibly with CO2 to generate carbamates and bicarbonates, thereby achieving efficient removal of CO2 from the gas. Although MEA and other alkanolamine aqueous solution absorbents have a certain industrial foundation, they still have several significant problems in practical applications: Traditional alkanolamine absorbents are usually aqueous solutions of about 30 wt%, and their CO2 absorption is an exothermic reaction. The desorption process requires a large amount of heat energy, especially since the latent heat of vaporization of water accounts for a large proportion of the overall regeneration energy consumption. This results in the energy consumption per ton of CO2 captured generally being between 3.0 and 4.0 GJ / t CO2, which is not conducive to optimizing the energy efficiency of the capture system. At the same time, alkanolamines are prone to thermal degradation and oxidative degradation under high-temperature desorption conditions, generating byproducts such as organic acids, aldehydes, and imines. This not only affects the long-term stable use of the absorbent but may also lead to equipment corrosion and system performance deterioration.

[0003] To address the aforementioned issues, various novel CO2 absorbent systems have been proposed both domestically and internationally in recent years, including solid amines, ionic liquids, eutectic solvents, and organic amine / non-aqueous solvent mixtures. Among these, non-aqueous alcohol amine systems have become a hot research topic in recent years due to their combination of the fluidity and ease of operation of liquid absorbents, while also reducing regeneration energy consumption, increasing CO2 loading, and improving solvent stability by reducing water content.

[0004] Developing non-aqueous alcohol amine absorbents with low energy consumption, low corrosivity, good stability, and high carbon dioxide absorption capacity has always been a challenge and a hot topic in carbon dioxide capture technology research.

[0005] Piperazine (PZ), as the main component of existing flue gas decarbonization absorbents, has advantages such as high boiling point, low volatility and no ammonia odor compared with linear polyamines. However, it has high regeneration energy consumption and limited cycle absorption stability, which affects the stability of the decarbonization system.

[0006] Chinese patent CN110152452A discloses a ternary non-aqueous solid-liquid phase change absorption system and its application. The system is a ternary mixture composed of 2-amino-2-methyl-1-propanol, dipropylene glycol dimethyl ether, and piperazine. Before absorbing CO2, the system is a homogeneous, transparent liquid solution; after absorbing CO2, it becomes a solid-liquid two-phase system, with CO2 concentrated in the solid phase. The solid phase can be separated and regenerated. However, continuous operation of the solid-liquid phase separation is difficult, and existing devices cannot meet production needs, limiting the use of large-scale industrial absorption towers.

[0007] Chinese patent application CN111097255A discloses a functionalized ionic liquid non-aqueous system specifically for CO2 absorption and separation. It consists of the following components by mass: ethylene glycol or propylene glycol: 70-90%; amino-functionalized ionic liquid: 5-15%; piperazine: 5-15%. The amino-functionalized ionic liquid has an N,N-methylaminoethylpiperazine cation and an amino acid anion. While ionic liquids possess characteristics such as ultra-low vapor pressure and high thermal stability, the viscosity of most ionic liquids increases significantly under medium to high CO2 loads, leading to a decrease in diffusion coefficient and limited mass transfer. Furthermore, the raw materials, synthesis, and purification costs of ionic liquids are relatively high, increasing operating costs.

[0008] Therefore, there is an urgent need to develop an absorbent that has high capture efficiency, excellent low-temperature desorption performance, and long-term cycle stability to meet the actual needs of industrial-scale carbon capture. Summary of the Invention

[0009] The purpose of this invention is to overcome the aforementioned defects in the prior art and provide an absorbent liquid for capturing carbon dioxide with low-temperature desorption and high cycle stability, as well as its preparation method and application. This invention utilizes the synergistic effect of composite antioxidants and desorption promoters to form a highly efficient capture system together with the main absorbent component and solvent. By adjusting the ratio between the composite antioxidants and desorption promoters, a polyol amine absorbent is obtained through compounding. This allows the system to maintain high capture efficiency while possessing excellent low-temperature desorption performance and long-term cycle stability, ensuring the long-term stable and efficient operation of the amine liquid. This reduces operating costs caused by amine liquid degradation, equipment corrosion, and high energy consumption. It is suitable for the efficient capture of carbon dioxide in industrial exhaust gas or flue gas, exhibiting excellent performance in low-temperature capture, low regeneration energy consumption, good long-term cycle stability, and high carbon dioxide absorption capacity.

[0010] To achieve the above objectives, the technical solution of the present invention is as follows:

[0011] An absorbent for capturing carbon dioxide with low-temperature desorption and high cycling stability comprises the following components in weight percentage: 15%~45% main absorbent component, 0.5%~5% auxiliary agent, and the balance being solvent; wherein the main absorbent component is at least one selected from N-ethylpiperazine, 1-methylpiperazine, and N-hydroxyethylpiperazine; wherein the solvent is at least one selected from 1-dimethylamino-2-propanol, diethylaminoethanol, and N,N-dimethylethanolamine; wherein the auxiliary agent is selected from a composite antioxidant and a desorption promoter in a mass ratio of (1.5~2.5):1; wherein the composite antioxidant is selected from 10-alkylphenthiazine and 1-isopropyl-4-piperidinol in a mass ratio of 1:(1~1.5); and wherein the desorption promoter is selected from 2-(tert-butyl)pyridin-3-ol.

[0012] The present invention also discloses a method for preparing an absorbent liquid for capturing carbon dioxide with low-temperature desorption and high cycling stability as described above, comprising the following steps: adding the main absorbent component and the auxiliary agent to a solvent for mixing to obtain the absorbent liquid.

[0013] The present invention also discloses the application of the above-described absorbent with low-temperature desorption and high cycle stability for capturing carbon dioxide in industrial exhaust gas.

[0014] Implementing the embodiments of the present invention will have the following beneficial effects:

[0015] In the non-aqueous piperazine system of this invention, a highly efficient capture system is formed through the synergistic effect of a composite antioxidant and a desorption promoter, together with the main absorbent component and the solvent. The main absorbent component achieves high reactivity and absorption rate. The solvent constitutes a non-aqueous basic liquid phase, reducing regeneration energy consumption. Furthermore, 10-alkylphenothiazine, with its electron-rich nitrogen and sulfur heteroatom structure in the phenothiazine core, helps capture free radicals in the system; 1-isopropyl-4-piperidinol utilizes the basic sites provided by the tertiary amine nitrogen atom in its molecule. The combination of these two enhances the stability of the amine solution during long-term thermal cycling. The introduction of the desorption promoter 2-(tert-butyl)pyridin-3-ol, with its steric hindrance groups and polar functional groups, effectively lowers the energy barrier of the CO2 desorption process, achieving low-temperature desorption and thus low regeneration energy consumption.

[0016] The absorbent of this invention, under absorption conditions of 40°C and atmospheric pressure, has an absorption time of 60 min, an absorption rate of 0.074~0.087 L / min, and an absorption capacity of 4.44~5.2 L (CO2) / 100g absorbent. It also exhibits excellent low-temperature desorption performance, maintaining excellent absorption and desorption performance even at 80°C. Furthermore, it demonstrates outstanding cycle stability, maintaining 96.7~99.2% performance after ten desorption cycles, ensuring long-term stable and efficient operation of the amine solution. This reduces amine loss, energy consumption, and economic costs and performance degradation caused by equipment corrosion. It meets the industrial requirements for absorbents with low regeneration energy consumption, good long-term cycle stability, and high carbon dioxide absorption capacity, and can be applied to CO2 capture in flue gas, steel plant tail gas, and chemical plant tail gas, showing promising application prospects. Attached Figure Description

[0017] Figure 1 This is a diagram of an absorption and desorption apparatus.

[0018] In the diagram: 1: Mass flow meter; 2: Buffer bottle; 3: Three-necked flask; 4: Rotor; 5: Oil bath; 6: Thermometer; 7: Condenser; 8: Drying bottle; 9: Wet corrosion-resistant flow meter; 10: Gas chromatograph; 11: Computer. Detailed Implementation

[0019] The present invention will be further described below with reference to specific embodiments, but this does not limit the present invention in any way.

[0020] This invention discloses an absorbent for capturing carbon dioxide with low-temperature desorption and high cycling stability, comprising the following components by mass percentage: 15%~45% main absorbent component, 0.5%~5% auxiliary agent, and the balance being solvent; the main absorbent component is at least one selected from N-ethylpiperazine, 1-methylpiperazine, and N-hydroxyethylpiperazine; the solvent is at least one selected from 1-dimethylamino-2-propanol, diethylaminoethanol, and N,N-dimethylethanolamine; the auxiliary agent is selected from a composite antioxidant and a desorption promoter in a mass ratio of (1.5~2.5):1; the composite antioxidant is selected from 10-alkylphenthiazine and 1-isopropyl-4-piperidinol in a mass ratio of 1:(1~1.5); and the desorption promoter is selected from 2-(tert-butyl)pyridin-3-ol.

[0021] In one specific embodiment, 10-alkylphenothiazine is selected from at least one of 10-methylphenothiazine, 10-ethylphenothiazine, and 10-hexylphenothiazine.

[0022] In one specific embodiment, the mass ratio of the composite antioxidant to the desorption promoter is 2:1.

[0023] In one specific embodiment, the mass ratio of 10-alkylphenothiazine to 1-isopropyl-4-piperidinol is 1:1.5.

[0024] In one specific embodiment, the mass ratio of the main absorbent component to the auxiliary agent is (20~50):1.

[0025] The present invention also discloses a method for preparing an absorbent liquid with low-temperature desorption and high cycling stability for capturing carbon dioxide as described above, comprising the following steps: adding the main absorbent component and the auxiliary agent to a solvent for mixing to obtain the absorbent liquid.

[0026] In one specific embodiment, the mixing temperature is 25~40°C; the mixing time is 10~30 min.

[0027] The present invention also discloses the application of the above-described absorbent with low-temperature desorption and high cycle stability for capturing carbon dioxide in industrial exhaust gas.

[0028] In one specific embodiment, the cycle efficiency is 96.7-99.2% after ten consecutive absorption-desorption cycles.

[0029] In one specific embodiment, industrial exhaust gas includes at least one of flue gas, steel plant exhaust gas, metallurgical plant exhaust gas, chemical plant exhaust gas, coal / oil / gas power generation boiler exhaust gas, and cement kiln exhaust gas.

[0030] In one specific embodiment, the volume fraction of CO2 in the industrial exhaust gas is 5% to 50%.

[0031] In one specific embodiment, the application conditions are as follows: under the conditions of absorption temperature of 40°C and absorption pressure of atmospheric pressure, the absorption time is 60 min, followed by desorption regeneration under the conditions of desorption temperature of 80~110°C and desorption pressure of atmospheric pressure, the desorption time is 60 min, the absorption rate is 0.074~0.087 L / min, the absorption amount is 4.44~5.2 L (CO2) / 100g absorbent, the desorption rate is 0.052~0.074 L / min, and the desorption rate is 69.93~99.55%.

[0032] The following are specific embodiments.

[0033] Example 1

[0034] The absorbent for capturing carbon dioxide at low temperature and with high cycling stability in this embodiment comprises the following components by mass percentage: 20% 1-methylpiperazine, 0.6% auxiliaries, and the balance being the solvent N,N-dimethylethanolamine.

[0035] The adjuvant is selected from a composite antioxidant and a desorption promoter 2-(tert-butyl)pyridine-3-ol in a mass ratio of 2:1.

[0036] The composite antioxidant is selected from 10-hexylphenthiazide and 1-isopropyl-4-piperidinol in a mass ratio of 1:1.5.

[0037] The method for preparing the absorbent liquid for capturing carbon dioxide with low-temperature desorption and high cycling stability in this embodiment includes the following steps: adding the main absorbent component and auxiliary agent to a solvent and mixing at 30°C for 20 minutes to obtain the absorbent liquid.

[0038] Example 2-Example 3

[0039] The only difference between this embodiment and Example 1 is that 10-hexylphenothiazine is replaced with 10-methylphenothiazine (Example 2) and 10-ethylphenothiazine (Example 3), respectively.

[0040] Examples 4-5

[0041] The only difference between this embodiment and Example 1 is that the mass ratio of the composite antioxidant and the desorption promoter 2-(tert-butyl)pyridine-3-ol is 1.5:1 (Example 4) and 2.5:1 (Example 5), respectively.

[0042] Example 6

[0043] The only difference between this embodiment and Example 1 is that the mass ratio of 10-alkylphenothiazine and 1-isopropyl-4-piperidinol is 1:1.

[0044] Example 7

[0045] The only difference between this embodiment and Example 1 is that the mass ratio of the main absorbent component to the auxiliary agent is 50:1.

[0046] The absorbent in this embodiment comprises the following components by mass percentage: 35% main absorbent component, 0.7% auxiliary agent, and the balance being solvent.

[0047] Example 8

[0048] The only difference between this embodiment and Example 1 is that the mass ratio of the main absorbent component to the auxiliary agent is 20:1.

[0049] The absorbent in this embodiment comprises the following components by mass percentage: 30% main absorbent component, 1.5% auxiliary agent, and the balance being solvent.

[0050] Example 9

[0051] The only difference between this embodiment and Example 1 is that the main absorbent component is N-ethylpiperazine and the solvent is 1-dimethylamino-2-propanol.

[0052] Example 10

[0053] The only difference between this embodiment and Example 1 is that the main absorbent component is N-hydroxyethylpiperazine and the solvent is diethylaminoethanol.

[0054] Comparative Example 1

[0055] The only difference between this comparative example and Example 1 is that no composite antioxidant and desorption promoter are added.

[0056] The absorbent in this comparative example comprises the following components by mass percentage: 20.6% main absorbent component, with the remainder being solvent.

[0057] Comparative Example 2

[0058] The only difference between this comparative example and Example 1 is that no desorption promoter is added.

[0059] The absorbent solution of this comparative example comprises the following components by mass percentage: 20% main absorbent component, 0.6% composite antioxidant, and the balance being solvent.

[0060] The composite antioxidant is selected from 10-hexylphenthiazide and 1-isopropyl-4-piperidinol in a mass ratio of 1:1.5.

[0061] Comparative Example 3

[0062] The only difference between this comparative example and Example 1 is that no composite antioxidant is added.

[0063] The absorbent in this comparative example comprises the following components by mass percentage: 20% main absorbent component, 0.6% desorption promoter 2-(tert-butyl)pyridine-3-ol, and the balance being solvent.

[0064] Comparative Example 4

[0065] The only difference between this comparative example and Example 1 is that 10-hexylphenthiazide is not added.

[0066] The absorbent solution of this comparative example comprises the following components by mass percentage: 20% main absorbent component, 0.6% auxiliary agent, and the balance being solvent.

[0067] The adjuvant is selected from 1-isopropyl-4-piperidinol and desorption promoter 2-(tert-butyl)pyridine-3-ol in a mass ratio of 2:1.

[0068] Comparative Example 5

[0069] The only difference between this comparative example and Example 1 is that 1-isopropyl-4-piperidinol is not added.

[0070] The absorbent solution of this comparative example comprises the following components by mass percentage: 20% main absorbent component, 0.6% auxiliary agent, and the balance being solvent.

[0071] The adjuvant is selected from 10-hexylphenthiazide and desorption promoter 2-(tert-butyl)pyridine-3-ol in a mass ratio of 2:1.

[0072] Comparative Examples 6-7

[0073] The only difference between this comparative example and Example 1 is that the mass ratio of the composite antioxidant and the desorption promoter 2-(tert-butyl)pyridine-3-ol is 1:1 (Comparative Example 6) and 3:1 (Comparative Example 7), respectively.

[0074] Comparative Examples 8-9

[0075] The only difference between this comparative example and Example 1 is that the mass ratio of 10-alkylphenothiazine and 1-isopropyl-4-piperidinol is 2:1 (Comparative Example 8) and 1:2 (Comparative Example 9), respectively.

[0076] Application Example 1

[0077] The total amine mass of the above examples and comparative examples, 100g each, was separately loaded into 250mL reactors equipped with a constant temperature oil bath stirrer (experimental setup see...). Figure 1 At 40℃, CO2 with a concentration of 99.995% and a pressure of 0.2MPa was introduced at a flow rate of 300mL / min. The flow was continuously measured for 60min using a wet scrubber to determine the amount and rate of carbon dioxide absorption. After the solution reached saturation, desorption was performed for 60min at oil bath temperatures of 80, 90, 100, or 110℃, and the desorption amount and rate were measured. The test results are shown in Table 1.

[0078] The formula for calculating the absorption rate is as follows: (1)

[0079] The formula for calculating the desorption rate is as follows: (2)

[0080] Among them, V a Absorption rate (L / min), V d Desorption rate (L / min), V0: inlet gas flow rate (L / min), t: measurement time (min), V t : The cumulative volume (L) of CO2 at the outlet of the wet gas flow meter within t min.

[0081] Application Example 2

[0082] The total amine mass of the above examples and comparative examples was 100g and placed into a 250mL reactor equipped with a constant temperature oil bath stirrer (experimental setup see [link]). Figure 1After the solution reaches saturation, the oil bath temperature is set to 80, 90, 100 or 110℃ for desorption for 60 minutes. This cycle is repeated ten times, with other conditions the same as in Application Example 1. The test results are shown in Table 1.

[0083] Table 1

[0084]

[0085] Results analysis:

[0086] As shown in Table 1, the carbon dioxide absorption capacity, desorption capacity, and cycle efficiency after ten desorption cycles of the absorbent of this invention are significantly better than those of the comparative solutions within 60 min. Taking Example 1 as an example, at 110 °C, the carbon dioxide absorption capacity was 4.48 L and the desorption capacity was 4.46 L within 60 min. After ten desorption cycles, the cycle efficiency reached 99.2%, which is significantly higher than the absorption capacity of approximately 4.05–4.18 L, the desorption capacity of 2.60–3.00 L, and the cycle efficiency of 94.5%–96.0% of Comparative Examples 1–9. This indicates that, in non-aqueous solvents, the introduction of the main absorbent component, the composite antioxidant, and the desorption promoter can significantly improve the desorption performance and cycle stability while ensuring a high absorption capacity.

[0087] The results from Example 1 at different desorption temperatures show that as the desorption temperature significantly decreases from 110°C to 80°C, the desorption rate remains at 69.93% after 60 minutes, and the efficiency remains at 96.7% after ten cycles. This indicates that even at a low temperature of 80°C, the solution can still maintain a high desorption rate and cycle efficiency, verifying that the non-aqueous amine system of this invention has low-temperature desorption and high cycle stability, thereby achieving low regeneration energy consumption and good regeneration adaptability.

[0088] Comparative examples 2 to 6 show that, under the conditions of a main absorbing amine mass fraction of 20% and the same total content of adjuvants, changing the alkyl chain structure of 10-alkylphenothiazine in the composite antioxidant or slightly adjusting the mass ratio of the composite antioxidant to the desorption promoter resulted in a carbon dioxide absorption capacity that remained relatively stable between 4.44 and 4.48 L within 60 min, a desorption capacity that remained relatively stable between 4.35 and 4.43 L, a desorption rate that remained relatively stable between 97.97 and 98.88%, and a cycle efficiency that remained between 98.4% and 99.0%. This indicates that within the ratio range defined in this invention, phenothiazines with different alkyl substitutions can synergistically exert antioxidant effects with 1-isopropyl-4-piperidinol, and, combined with the desorption promoting effect of 2-(tert-butyl)pyridin-3-ol, enable the system to maintain high and stable absorption and desorption performance in multiple cycles.

[0089] Comparing Examples 7 and 8, it can be seen that as the content of the main absorbing amine increased from 20% (Example 1) to 30% (Example 8) and 35% (Example 7), the absorption capacity at 60 min was 5.0 L and 5.20 L, respectively, and the desorption capacity was 4.38 L and 4.39 L, respectively, with desorption rates of 87.6% and 84.42%, respectively. This indicates that the mass ratio of the main absorbing component to the adjuvant has a significant impact on the synergistic achievement of high absorption capacity, high desorption efficiency, and long-term cycling stability.

[0090] Further comparison of the comparative examples shows that when specific components in the composite antioxidant were removed (Comparative Examples 4-5), the composite antioxidant was removed (Comparative Example 3), the desorption promoter was removed (Comparative Example 2), or no adjuvant was added at all (Comparative Example 1), the desorption capacity at 60 min decreased to 2.60–2.78 L, and the efficiency after ten cycles decreased to approximately 94.5%–95.4%, indicating that it is difficult to simultaneously ensure sufficient desorption capacity and cycling stability when adding or not adding adjuvants. Even when only the internal component ratio of the composite antioxidant or the mass ratio of 10-alkylphenothiazine to 1-isopropyl-4-piperidinol was changed (Comparative Examples 6–9), the desorption capacity and cycling efficiency were still significantly lower than in the corresponding examples. This indicates that it is difficult to simultaneously ensure sufficient desorption capacity and cycling stability when adding or not adding adjuvants.

[0091] In summary, the key to achieving high absorption capacity, low-temperature desorption, and high cycling stability of the absorbent liquid of this invention lies in the synergistic effect of the composite antioxidant and desorption promoter, as well as the control of the main absorbent amine and auxiliary agents within a specific mass fraction and ratio range.

[0092] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the scope of protection of the present invention. Therefore, the scope of protection of this patent should be determined by the appended claims.

Claims

1. An absorbent for capturing carbon dioxide using low-temperature desorption and high cycling stability, characterized in that, It consists of the following components by mass percentage: 15%~45% main absorbent component, 0.5%~5% auxiliary agent, balance is solvent; The main absorber component is at least one of N-ethylpiperazine, 1-methylpiperazine and N-hydroxyethylpiperazine; The solvent is at least one of 1-dimethylamino-2-propanol and N,N-dimethylethanolamine; The adjuvant is selected from a composite antioxidant and a desorption promoter in a mass ratio of (1.5~2.5):1; The composite antioxidant is selected from 10-alkylphenthiazide and 1-isopropyl-4-piperidinol in a mass ratio of 1:(1~1.5); The desorption promoter is selected from 2-(tert-butyl)pyridine-3-ol; The mass ratio of the main absorbent component to the auxiliary agent is (20~50):1; The absorption liquid has a cycle efficiency of 96.7% to 99.2% after ten consecutive absorption-desorption cycles. Under the conditions of absorption temperature of 40℃, absorption pressure of atmospheric pressure, and absorption time of 60 min, desorption and regeneration were carried out under the conditions of desorption temperature of 80~110℃, desorption pressure of atmospheric pressure, and desorption time of 60 min. The absorption rate was 0.074~0.087 L / min, the absorption capacity was 4.44~5.2 L (CO2) / 100g absorbent, the desorption rate was 0.052~0.074 L / min, and the desorption rate was 69.93~99.55%.

2. The absorbent for capturing carbon dioxide with low-temperature desorption and high cycling stability according to claim 1, characterized in that, The 10-alkylphenothiazine is selected from at least one of 10-methylphenothiazine, 10-ethylphenothiazine, and 10-hexylphenothiazine.

3. The absorbent for capturing carbon dioxide with low-temperature desorption and high cycling stability according to claim 1, characterized in that, The mass ratio of the composite antioxidant to the desorption promoter is 2:

1.

4. The absorbent for capturing carbon dioxide with low-temperature desorption and high cycling stability according to claim 1, characterized in that, The mass ratio of the 10-alkylphenothiazine to 1-isopropyl-4-piperidinol is 1:1.

5.

5. A method for preparing an absorbent liquid for capturing carbon dioxide with low-temperature desorption and high cycling stability as described in any one of claims 1-4, characterized in that, The process includes the following steps: adding the main absorbent component and auxiliary agent to a solvent for mixing to obtain the absorbent liquid.

6. The method for preparing the absorbent for capturing carbon dioxide with low-temperature desorption and high cycling stability according to claim 5, characterized in that, The mixing temperature is 25~40℃; the mixing time is 10~30min.

7. The application of an absorbent liquid with low-temperature desorption and high cycle stability for capturing carbon dioxide as described in any one of claims 1-4 in capturing carbon dioxide from industrial exhaust gas.

8. The application according to claim 7, characterized in that, In the aforementioned application, the cycle efficiency is 96.7-99.2% after ten consecutive absorption-desorption cycles.

9. The application according to claim 7, characterized in that, The industrial exhaust gas includes at least one of the following: flue gas, steel plant exhaust gas, metallurgical plant exhaust gas, chemical plant exhaust gas, power plant boiler exhaust gas, and cement kiln exhaust gas. The volume fraction of CO2 in the industrial exhaust gas is 5% to 50%. The application conditions are as follows: under the conditions of absorption temperature of 40°C and absorption pressure of atmospheric pressure, the absorption time is 60 min, followed by desorption and regeneration under the conditions of desorption temperature of 80~110°C and desorption pressure of atmospheric pressure, the desorption time is 60 min, the absorption rate is 0.074~0.087 L / min, the absorption capacity is 4.44~5.2 L (CO2) / 100g absorbent, the desorption rate is 0.052~0.074 L / min, and the desorption rate is 69.93~99.55%.

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