Anhydrous absorbent with self-extraction function and application and recovery method thereof

Abstract

The invention relates to the technical field of CO2 capture and separation, and particularly discloses an anhydrous absorbent with a self-extraction function as well as application and a recovery method. The anhydrous absorbent is synergistically composed of a mixed amine absorption enhancer with specific composition and a hydrophobic organic solvent, wherein the mixed amine absorption enhancer comprises primary amine, secondary amine and tertiary amine. The mixed amine absorption accelerant combines the advantages of high reaction activity of primary amine, low regeneration heat of secondary amine and high absorption capacity and strong hydrophobicity of tertiary amine, so that the anhydrous absorbent shows excellent self-extraction capacity in the adsorption and desorption processes of acid gas, particularly, the anhydrous absorbent after absorbing the acid gas forms a less-water CO2 rich phase, and the CO2 rich phase has excellent self-extraction capacity. And due to the characteristic of less water, sensible heat and latent heat of vaporization required by a rich phase in a CO2 desorption stage are remarkably reduced, so that the problem that the energy consumption is too high in the regeneration process of the existing water-based absorbent is effectively solved.

Description

Technical Field

[0001] The present application relates to the technical field of CO2 capture and separation, and in particular to an anhydrous absorbent with self-extraction function and an application and recovery method thereof. Background Art

[0002] Global warming, extreme weather and food crisis caused by greenhouse gas emissions are becoming increasingly serious. CO2, as the main greenhouse gas, is inevitably produced in the process of human production and life. Carbon capture and storage (CCS) technology is widely regarded as a key technical means to reduce CO2 emissions in fossil energy power generation and industrial processes. In particular, chemical absorption is currently a more effective technology for capturing carbon in flue gas from coal-fired power plants.

[0003] At present, the first generation of aqueous absorbents represented by ethanolamine absorbents have been widely used in industry. In terms of the capture energy consumption of absorbents, it mainly includes reaction heat, sensible heat and latent heat of vaporization. Compared with organic solvents, the sensible heat and vaporization enthalpy of water are usually at a higher level, which makes the sensible heat and vaporization heat of aqueous absorbents generally higher than those of anhydrous absorbents. For example, when regenerating a CO2 saturated solution of 30 wt% MEA, the energy required is about 3.8 GJ / t CO2. Such a high cost of absorbent regeneration operation has greatly limited the widespread promotion and application of chemical absorption. At the same time, this type of absorbent also has many shortcomings such as small absorption capacity, high corrosiveness and high regeneration energy consumption, which has caused traditional aqueous absorbents to face many technical difficulties.

[0004] In recent years, anhydrous absorbents have attracted widespread attention from researchers due to their significant advantages in reducing regeneration energy consumption, such as the anhydrous absorbent composed of tetramethylammonium glycine and sulfone (dimethyl sulfoxide or cyclopentane sulfone) disclosed in the Chinese invention patent (CN202110963405.5). However, the flue gas of coal-fired power plants contains about 13% volume fraction of water, which makes it very easy for anhydrous absorbents to absorb this part of water during the carbon capture process, and then convert it into a water-reducing absorbent, increasing the energy consumption of the absorbent in the pyrolysis recovery process. In view of this, it is very important to enhance the hydrophobicity of anhydrous absorbents. Therefore, it is urgent to develop new CO2 absorbents with strong hydrophobicity. Summary of the invention

[0005] In view of this, the purpose of the present application is to provide an anhydrous absorbent with self-extraction function and an application and recovery method, so as to solve the problem of high regeneration energy consumption of existing anhydrous absorbents.

[0006] In order to achieve the above technical purpose, the present application provides a water-free absorbent with self-extraction function, comprising the following components in mass percentage:

[0007] 30-40% of mixed amine absorption promoter, and the mixed amine absorption promoter includes primary amine, secondary amine and tertiary amine;

[0008] The balance is a hydrophobic organic solvent.

[0009] Furthermore, in the mixed amine absorption promoter, the primary amine is benzylamine; the secondary amine is one of N-methylbenzylamine, diethanolamine, N-methylmonoethanolamine, and hydroxyethylethylenediamine; and the tertiary amine is N,N-dimethylbenzylamine.

[0010] Furthermore, in the mixed amine absorption promoter, by mass percentage, benzylamine accounts for 5-10%; N-methylbenzylamine accounts for 20-35%; and N,N-dimethylbenzylamine accounts for 60-70%.

[0011] Furthermore, the hydrophobic organic solvent includes one of n-octanol, isoamyl alcohol, p-xylene, trifluorotoluene, cyclohexane, and butyl acetate.

[0012] The present application provides an application of an anhydrous absorbent with a self-extraction function, which is used for absorbing weakly acidic gases.

[0013] Furthermore, the weakly acidic gas includes one or more of CO2, sulfur dioxide, and hydrogen sulfide.

[0014] Furthermore, when anhydrous absorbent is used to adsorb gas including CO2, the adsorption temperature is set to 30-40°C.

[0015] The present application provides a method for regenerating an anhydrous absorbent with a self-extraction function, comprising the following steps: the anhydrous absorbent is desorbed by thermal decomposition to achieve regeneration.

[0016] Furthermore, the pyrolysis temperature is 105~120 °C, and the pyrolysis time is 10~20 min.

[0017] Furthermore, the pyrolysis temperature was 105 °C and the pyrolysis time was 10 min.

[0018] In summary, the present application innovatively proposes an anhydrous absorbent system for capturing acidic gases. The system is composed of a mixed amine absorption promoter of a specific composition and a hydrophobic organic solvent, wherein the mixed amine absorption promoter comprises primary amines, secondary amines and tertiary amines. Because the mixed amine absorption promoter combines the advantages of high reactivity of primary amines, low regeneration heat of secondary amines, high absorption capacity and strong hydrophobicity of tertiary amines, and is adapted to the hydrophobic organic solvent, the anhydrous absorbent exhibits excellent self-extraction ability during the adsorption and desorption of acidic gases, especially after absorbing acidic gases, the anhydrous absorbent forms a CO2-rich phase with little water. Due to its low water characteristic, the sensible heat and latent heat of vaporization required for the rich phase in the CO2 desorption stage are significantly reduced, thereby effectively overcoming the problem of excessive energy consumption of existing aqueous absorbents during the regeneration process.

[0019] Compared with the prior art, the anhydrous absorbent provided in the present application can separate the water in the flue gas to the greatest extent while promoting the high enrichment of CO2 in the upper phase, greatly improving the capture and separation efficiency of CO2. In addition, after absorbing the flue gas, the anhydrous absorbent can achieve efficient regeneration at a relatively low desorption temperature and a very short desorption time, which not only reduces energy consumption, but also provides a feasible technical approach for energy conservation and emission reduction, and has broad application prospects in industrial waste gas treatment, especially in the field of acid gas capture. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0021] Figure 1 Schematic diagram of the simulated flue gas absorption device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0022] The technical solutions of the embodiments of the present application will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the specification of the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection requested by the present application.

[0023] The sources of all raw materials in the present invention are not particularly limited and can be purchased from the market or prepared according to conventional methods known to those skilled in the art.

[0024] The embodiment of the present invention provides a water-free absorbent having a self-extraction function, comprising the following components in percentage by mass:

[0025] 30-40% of mixed amine absorption promoter, and the mixed amine absorption promoter includes primary amine, secondary amine and tertiary amine;

[0026] The balance is a hydrophobic organic solvent.

[0027] It should be noted that most flue gases contain a certain amount of moisture. Taking the flue gas from coal-fired power plants as an example, the volume fraction of water is about 13%. In the carbon capture process, conventional anhydrous absorbents tend to absorb this part of the water in the flue gas, and then transform into less-water absorbents, which reduces the hydrophobicity of the anhydrous absorbent, causing the water content in the anhydrous absorbent that has absorbed the flue gas to increase significantly, ultimately leading to an increase in the energy consumption of later heating and regeneration. It can be seen that it is particularly important to enhance the hydrophobicity of the anhydrous absorbent so that it can gradually drain water while absorbing the moisture in the flue gas. The anhydrous absorbent of this scheme is composed of a hydrophobic organic solvent and a mixed amine absorption promoter. The difference in polarity between the two will cause the CO2 in the flue gas to be enriched in the anhydrous absorbent to form an upper phase. At the same time, the hydrophobic organic solvent will separate the moisture in the flue gas from the anhydrous absorbent to form a lower phase.

[0028] In some embodiments, in the mixed amine absorption enhancer, the primary amine is benzylamine; the secondary amine is one of N-methylbenzylamine, diethanolamine, N-methylmonoethanolamine, and hydroxyethylethylenediamine; and the tertiary amine is N,N-dimethylbenzylamine.

[0029] Preferably, in the mixed amine absorption promoter, by mass percentage, benzylamine accounts for 5-10%; N-methylbenzylamine accounts for 20-35%; and N,N-dimethylbenzylamine accounts for 60-70%.

[0030] It should be noted that the mixed amine absorption promoter formed by using the above three amine absorption promoters in a specific ratio has a total amine concentration of 1.6~4.0 mol / kg, has good hydrophobicity, and is only slightly soluble in water at room temperature. This concentration range not only ensures the chemical activity of the absorption promoter, but also maintains its compatibility and stability in different solvent systems. In the mechanism of gas capture, benzylamine, as a primary amine, has a strong nucleophilicity of the lone pair of electrons of the amino group in its molecular structure, and exhibits extremely high reactivity to acidic gases. This characteristic makes benzylamine the core subject of the capture process; N-methylbenzylamine, as a secondary amine, plays a key role in optimizing the reaction heat of the absorption promoter in the system; N, N-dimethylbenzylamine, as a tertiary amine, plays multiple important roles in the mixed amine system: on the one hand, it can provide additional absorption capacity for primary and secondary amines, and enhance the carrying capacity of the entire absorption system for CO2; on the other hand, N, N-dimethylbenzylamine significantly enhances the hydrophobicity of the absorbent by virtue of its unique molecular structure and electron cloud distribution. The mixed amine absorption promoter formed by combining the above three amine absorption promoters, when facing a flue gas environment containing moisture, has a higher hydrophobicity that can not only reduce the negative interference of moisture on the absorption performance, improve the capture, separation and enrichment effect of the absorbent system on CO2, but also effectively reduce the energy consumption caused by the presence of a large amount of moisture in the subsequent desorption process.

[0031] In some embodiments, the hydrophobic organic solvent includes one of n-octanol, isoamyl alcohol, p-xylene, trifluorotoluene, cyclohexane, and butyl acetate.

[0032] It should be noted that hydrophobic organic solvents have lower latent heat of vaporization and specific heat capacity than water solvents. This characteristic greatly reduces the energy required to change the state of matter (latent heat) and increase the temperature (sensible heat) during the absorbent regeneration process, thereby effectively reducing the energy consumption during the desorption and regeneration process of the absorbent. In addition, the selected organic solvent is also an aprotic solvent, which is not prone to electrochemical corrosion and has low corrosiveness to equipment.

[0033] The present application provides an application of an anhydrous absorbent with a self-extraction function, which is used for absorbing weakly acidic gases.

[0034] In some embodiments, the weak acid gas includes one or more of CO2, sulfur dioxide, and hydrogen sulfide.

[0035] Specifically, when an anhydrous absorbent is used to adsorb the gas including CO2, the adsorption temperature is set to 30-40°C; in order to further improve the extraction efficiency of the anhydrous absorbent, the gas including CO2 is preheated at a preheating temperature of 30-40°C.

[0036] It should be noted that before the anhydrous absorbent is used to capture carbon from coal-fired flue gas, the system is in a homogeneous solution state. However, when the anhydrous absorbent contacts and absorbs the water in the coal-fired flue gas, the system undergoes phase separation to form an upper phase and a lower phase. Among them, the upper phase is a CO2-rich phase with less water, and the mass percentage of water in this phase is in the range of 10-15%; the lower phase is a CO2-less water phase, and the CO2 load in this phase is less than 5% of the total load. Further studies have shown that when the volume fraction of CO2 gas in the absorbed coal-fired flue gas is 5-20%, the volume fraction of water in the flue gas is 0-15%, and the flue gas temperature is 30-50 °C, the absorption load of the anhydrous absorbent is 0.30-0.63 mol / mol amine.

[0037] The present application provides a method for regenerating an anhydrous absorbent having a self-extraction function, comprising the following steps:

[0038] The anhydrous absorbent is regenerated by desorption through thermal decomposition.

[0039] Preferably, the pyrolysis temperature is 105-120°C, and the pyrolysis time is 10-20 min.

[0040] More preferably, the pyrolysis temperature is 105°C and the pyrolysis time is 10 min.

[0041] It should be noted that when the water-poor CO2-rich phase is heated, the hydrophobicity of the absorbent will gradually increase while the CO2-rich phase undergoes a regeneration process to generate CO2 and amines. Therefore, a small amount of water contained in the rich phase will be continuously separated from the absorbent. This process will also accelerate the desorption process of the anhydrous absorbent and help to quickly achieve the regeneration of the anhydrous absorbent. It is worth noting that due to the relatively low water content in the CO2-rich phase, the sensible heat and latent heat of vaporization required during the CO2 desorption process of the absorbent are greatly reduced, thus effectively solving the problem of excessive energy consumption of existing aqueous absorbents during the regeneration process.

[0042] The applicant further provides the following reference specific embodiments to describe the present invention. It should be noted that these embodiments are merely illustrative and do not limit the present invention in any way.

[0043] Example 1

[0044] This embodiment provides a water-free absorbent with self-extraction function, comprising the following percentages of components:

[0045] Mixed amine absorbent 30%; organic solvent 70%;

[0046] The mixed amine absorbent is composed of 5% benzylamine, 25% N-methylbenzylamine and 70% N,N-dimethylbenzylamine; the organic solvent is n-octanol.

[0047] This embodiment provides a method for regenerating an anhydrous absorbent having a self-extraction function, comprising the following steps:

[0048] Heat the anhydrous absorbent at 105°C for 10 min to obtain the anhydrous absorbent.

[0049] Example 2

[0050] The difference from Example 1 is that the mass percentage of n-octanol is 60%, and the mass percentage of the mixed amine absorption promoter is 40%.

[0051] Example 3

[0052] The difference from Example 1 is that benzylamine accounts for 10% by mass of the mixed amine absorbent, and N-methylbenzylamine accounts for 20% by mass of the mixed amine absorbent.

[0053] Example 4

[0054] The difference from Example 1 is that benzylamine accounts for 10% of the mass fraction of the mixed amine absorbent, and N,N-dimethylbenzylamine accounts for 65% of the mass fraction of the mixed amine absorbent.

[0055] Example 5

[0056] The difference from Example 1 is that N-methylbenzylamine accounts for 30% of the mass fraction of the mixed amine absorbent, and N,N-dimethylbenzylamine accounts for 65% of the mass fraction of the mixed amine absorbent.

[0057] Comparative Example 6

[0058] The difference from Example 1 is that the regeneration temperature is 120°C.

[0059] Comparative Example 7

[0060] The difference from Example 1 is that the regeneration time is 20 min.

[0061] Example 8

[0062] The difference from Example 1 is that N-methylbenzylamine accounts for 35% of the mass fraction of the mixed amine absorbent, and N,N-dimethylbenzylamine accounts for 60% of the mass fraction of the mixed amine absorbent.

[0063] Example 9

[0064] The difference from Example 1 is that the N-methylbenzylamine in the mixed amine absorption promoter is replaced by diethanolamine.

[0065] Example 10

[0066] The difference from Example 1 is that the N-methylbenzylamine in the mixed amine absorption promoter is replaced by N-methylmonoethanolamine.

[0067] Embodiment 11

[0068] The difference from Example 1 is that the N-methylbenzylamine in the mixed amine absorption promoter is replaced by hydroxyethylethylenediamine.

[0069] Comparative Example 1

[0070] The difference from Example 1 is that the organic solvent is ethanol.

[0071] Comparative Example 2

[0072] The difference from Example 1 is that the organic solvent is n-propanol.

[0073] Comparative Example 3

[0074] The difference from Example 1 is that the organic solvent is n-butanol.

[0075] Comparative Example 4

[0076] The difference from Example 1 is that the organic solvent is dimethyl sulfoxide.

[0077] Comparative Example 5

[0078] The difference from Example 1 is that the organic solvent is sulfolane.

[0079] Comparative Example 6

[0080] The difference from Example 1 is that the organic solvent is ethylene glycol.

[0081] Comparative Example 7

[0082] The difference from Example 1 is that the organic solvent is N-methyl-2-pyrrolidone.

[0083] Comparative Example 8

[0084] The difference from Example 1 is that the organic solvent is N,N-dimethylformamide.

[0085] Comparative Example 9

[0086] The difference from Example 1 is that the organic solvent is dimethyl ether.

[0087] Comparative Example 10

[0088] The difference from Example 1 is that the mixed amine absorbent is composed of benzylamine and N-methylbenzylamine, benzylamine accounts for 30% of the mass fraction of the mixed amine absorbent, and N-methylbenzylamine accounts for 70% of the mass fraction of the mixed amine absorbent.

[0089] Comparative Example 11

[0090] The difference from Example 1 is that the mixed amine absorption promoter contains only benzylamine, which accounts for 30% of the anhydrous absorbent.

[0091] The setting parameters of the above embodiments and comparative examples can also be referred to Table 1.

[0092] Table 1

[0093]

[0094] Extraction and separation experiment 1: The phase separation of the absorbents in the embodiment and the comparative example after the wet flue gas carbon capture was completed was measured. The specific test results are as follows:

[0095] According to the components of the embodiment and the comparative example, 40 g of anhydrous absorbent sample and simulated flue gas were prepared respectively, and the volume fractions of CO2 and water in the simulated flue gas reached 12% and 5% respectively; in the process of the experiment, in order to further highlight the stratification effect of the absorbent, the temperature of the simulated flue gas before entering the absorption device was adjusted to be divided into simulated flue gas at room temperature and simulated flue gas heated by a water bath (40°C). The prepared anhydrous absorbent was placed in the absorption tower of the simulated flue gas absorption device. The structure of the absorption device is detailed in Figure 1 During the experiment, the temperature of the absorption tower was strictly controlled to be constant at 40 °C, and the temperature of the desorption tower was strictly controlled to be constant at 105 °C. Then the simulated flue gas was passed into the absorption tower to allow the anhydrous absorbent to continuously absorb the simulated flue gas for 30 minutes. During the entire absorption stage, the absorbent system was observed, focusing on whether the anhydrous absorbent showed phase separation when the simulated flue gas at room temperature was passed in. The simulated flue gas was heated in a water bath at 40 °C and then passed into the absorption device. The detailed data of phase separation were observed and recorded. The results are shown in Table 1.

[0096] It is found in the experimental study for Examples 1 to 8 that each embodiment is in a homogeneous solution state before absorbing CO2, and after completing CO2 absorption, a two-phase solution system can be successfully formed. This phenomenon fully demonstrates that benzylamine, N-methylbenzylamine, N, N-dimethylbenzylamine are used as absorption amine promoters, and the anhydrous absorbent composed of a hydrophobic organic solvent has a significant self-extraction ability. In-depth analysis of the data of Examples 1 to 8 shows that after absorbing flue gas, the volume ratio of the separated lower phase will rise sharply with the decrease of the mass fraction of N, N-dimethylbenzylamine. When the mass fraction of N, N-dimethylbenzylamine is kept constant, as the mass of N-methylbenzylamine decreases, the volume of the lower phase solution shows an increasing trend, and the distribution ratio of CO2 products in the aqueous phase is also improved. Further analysis of the above results shows that if it is desired to optimize the hydrophobicity of the absorbent by mixing amine absorption promoters, the first measure should be to increase the concentration of N, N-dimethylbenzylamine, and the second is to increase the content of N-methylbenzylamine. However, in view of the consideration of CO2 capture performance, the mass concentration of primary or secondary amines in the absorbent should not be too low. From the data analysis of Examples 9 to 11, it can be seen that the anhydrous absorbent prepared by replacing N-methylbenzylamine with diethanolamine, N-methylmonoethanolamine, and hydroxyethylethylenediamine still has good adsorption, extraction, and desorption and regeneration capabilities.

[0097] Further analysis of comparative examples 1 to 9 shows that, except for comparative example 6, which is in a phase-separated state before absorbing flue gas, the other comparative examples are homogeneous before absorbing flue gas. After absorbing flue gas, the situation has changed significantly. Except for comparative example 6, which still maintains phase separation, comparative examples 2 to 3 show a stratified state after absorbing flue gas, but the volume of the lower phase accounts for a large proportion; the anhydrous absorbent provided by other comparative examples (simulating flue gas at room temperature) is still in a homogeneous state. Even if the simulated flue gas is heated in a water bath to promote the subsequent phase separation process, the volume proportion of the lower phase is still very large, indicating that the anhydrous absorbent provided by the comparative example has a large water solubility and is very easy to merge with the water of the lower phase, which is not conducive to separation and regeneration. This series of phenomena strongly illustrates that the selection of an organic solvent with hydrophobicity and compatible with the mixed amine promoter plays a key role in giving the anhydrous absorbent self-extraction ability. Suitable hydrophobic organic solvents can synergize with the absorption amine promoter to promote phase separation in the system and realize the self-extraction function in the process of absorbing CO2, thereby effectively improving the capture and separation efficiency of CO2 by the anhydrous absorbent.

[0098] Further analysis of comparative examples 10 to 11 shows that the mixed amine absorption promoter of comparative example 10 is benzylamine and N-methylbenzylamine, and the absorption promoter of comparative example 11 is benzylamine. Compared with Example 1, both of them form upper and lower phases after the absorption is completed. However, the volume ratio of the lower phase of Example 1 is only 15%, while the volume ratio of the lower phase of comparative examples 10 and 11 is 39% and 41%, respectively. It can be seen that the hydrophobicity of the tertiary amine N, N-dimethylbenzylamine plays an important role in it. It can enhance the attraction of the upper phase to the CO2 product and promote the CO2 product to be more enriched in the upper phase. This feature further illustrates the importance of N, N-dimethylbenzylamine in optimizing absorbent performance and improving CO2 capture and separation efficiency, and also provides a more targeted reference basis for the formulation design and performance optimization of anhydrous absorbents.

[0099] Thermal desorption experiment 2:

[0100] The CO2-rich upper phase obtained after absorbing flue gas in Examples 1 to 11 in Experiment 1 was selected as a sample. It was heated under specific temperature conditions in order to separate the anhydrous absorbent and explore the regeneration performance of the anhydrous absorbent. The relevant data of the optimal heating temperature and heating time are specifically shown in Table 1.

[0101] By analyzing the data of Examples 1 to 11 in Table 1, it can be seen that when the thermal desorption temperature is set in the range of 105 to 120 °C and the thermal desorption time is controlled at 10 to 20 minutes, the anhydrous absorbent can achieve a relatively ideal regeneration effect. It is worth noting that even if the thermal desorption temperature is set to 105 °C and the thermal desorption time is controlled to 10 minutes, the regeneration effect of the anhydrous absorbent is not significantly affected. This result fully demonstrates that the anhydrous absorbent can still exhibit excellent regeneration ability under relatively low regeneration temperature and short regeneration time conditions; it also shows that the absorbent has good stability during multiple cycles and can achieve multiple cycles of regeneration.

[0102] The above are only preferred embodiments of the present application and are not intended to limit the present invention. Although the present application has been described in detail with reference to the examples, those skilled in the art can still modify the technical solutions recorded in the aforementioned examples or make equivalent substitutions for some of the technical features therein. However, any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present application should be included in the protection scope of the present application.

Claims

1. A water-free absorbent having a self-extraction function, characterized in that: The following components are included in mass percentage: 30-40% of mixed amine absorption promoter, and the mixed amine absorption promoter includes primary amine, secondary amine and tertiary amine; The balance is a hydrophobic organic solvent.

2. The anhydrous absorbent with self-extraction function according to claim 1, characterized in that: In the mixed amine absorption promoter, the primary amine is benzylamine; the secondary amine is one of N-methylbenzylamine, diethanolamine, N-methylmonoethanolamine and hydroxyethylethylenediamine; and the tertiary amine is N,N-dimethylbenzylamine.

3. The anhydrous absorbent with self-extraction function according to claim 2, characterized in that: In the mixed amine absorption promoter, by mass percentage, benzylamine accounts for 5-10%; N-methylbenzylamine accounts for 20-35%; and N,N-dimethylbenzylamine accounts for 60-70%.

4. The anhydrous absorbent with self-extraction function according to claim 1, characterized in that: The hydrophobic organic solvent includes one of n-octanol, isoamyl alcohol, p-xylene, trifluorotoluene, cyclohexane, and butyl acetate.

5. Use of the anhydrous absorbent with self-extraction function as claimed in any one of claims 1 to 4, characterized in that: Used to absorb weak acidic gases.

6. The use of the anhydrous absorbent with self-extraction function according to claim 5, characterized in that: The weakly acidic gas includes one or more of CO2, sulfur dioxide, and hydrogen sulfide.

7. The use of the anhydrous absorbent with self-extraction function according to claim 6, characterized in that: When using anhydrous absorbent to adsorb gases including CO2, set the adsorption temperature to 30~40℃.

8. A method for regenerating the anhydrous absorbent having a self-extraction function as claimed in any one of claims 1 to 4, characterized in that: The following steps are involved: The anhydrous absorbent is desorbed by thermal decomposition to achieve regeneration.

9. The method for regenerating anhydrous absorbent with self-extraction function according to claim 8, characterized in that: The pyrolysis temperature is 105-120°C, and the pyrolysis time is 10-20 min.

10. The method for regenerating anhydrous absorbent with self-extraction function according to claim 9, characterized in that: The pyrolysis temperature is 105°C and the pyrolysis time is 10 min.

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