CO2 trapping absorbent, trapping regeneration device and trapping process

Abstract

The invention discloses a CO2 trapping absorbent which comprises 20%-50% of proton type ionic liquid, 20%-50% of a phase conversion driving agent and 20%-40% of water, and the phase inversion driving agent is one or a mixture of more of N, N-dimethyl formamide, N-methyl pyrrolidone, pentamethyldiethylenetriamine, tetramethylethylenediamine, tetramethylethylenediamine, tetramethylenediamine, tetramethylethylenediamine and dimethyl piperazine, and the phase inversion driving agent is one or a mixture of more of N, N-dimethyl formamide, N-methyl pyrrolidone, pentamethyldiethylenetriamine, tetramethylethylenediamine, tetramethylethylenediamine and dimethyl piperazine. The absorbent disclosed by the invention has the outstanding advantages of low viscosity, high absorption rate, high regeneration efficiency, high circulation capacity and low regeneration energy consumption, and has a good application prospect.

Description

Technical Field

[0001] The present invention belongs to the technical field of carbon dioxide absorption, and in particular relates to a high-efficiency, low-energy consumption CO2 capture absorbent, a capture device and a capture process. Background Art

[0002] The climate change problem caused by greenhouse gas emissions such as carbon dioxide (CO2) has attracted more and more widespread attention from the international community. The emission reduction situation is becoming increasingly severe. The huge demand for emission reduction has given rise to the large-scale development of the entire carbon capture, utilization and storage (CCUS) industry chain.

[0003] However, due to the lack of large-scale research, design and operation experience in low-concentration carbon dioxide capture, the current application level of CCUS technology is relatively weak.

[0004] Compared with the relatively small number of high-concentration (>70% V / V) CO2 capture resources, low-concentration CO2 carbon sources are more abundant in refining and petrochemical enterprises, and the scale effect brought by capturing low-concentration carbon sources is more significant, but the corresponding engineering development is more difficult. Developing a large-scale low-concentration CO2 low-cost capture process technology set and applying it on a large scale means overcoming the most challenging carbon capture technology bottleneck in the CCUS technology link, which has a demonstration significance and technical leadership role in the application and promotion of CCUS technology in the industry.

[0005] Chemical solvent absorption has been widely studied and is considered a reliable and low-cost method for reducing CO2 emissions from fossil fuel power plants. So far, amine-based absorption (mainly MEA solution) is the most effective technology for capturing CO2 from low-pressure, large-volume gas flows. MEA absorption liquid has the advantages of rapid reaction, effective absorption of CO2, and relatively cheap amines. At low temperatures (20~40°C), the reaction proceeds in the forward direction and releases heat; at high temperatures, the reaction proceeds in the reverse direction and the solution is regenerated. The characteristics of the reaction between MEA and CO2 are used in industry to achieve the purpose of CO2 recovery (or removal).

[0006] In recent years, ionic liquids have gradually entered the field of vision of researchers and been continuously developed as a new type of acid gas absorbent due to their high thermal stability, low vapor pressure, low corrosiveness, excellent absorption capacity and regeneration performance. Ionic liquids are very stable in nature, with almost zero vapor pressure, little loss during use, and low corrosiveness. These advantages make them have great potential in gas capture. More importantly, because ionic liquids are highly designable, amino structures can be introduced into anions and cations to capture carbon dioxide. Numerous scientists' experimental studies have shown that their absorption effect is quite satisfactory.

[0007] In order to reduce the defects of the existing chemical solvent absorption method, which has large latent heat and sensible heat, a two-phase absorbent came into being. Its mechanism is that two phases are produced after absorption, and carbon dioxide is enriched in one phase. During the regeneration process, only the enriched phase needs to be desorbed, and a part of the absorbed components do not participate in the regeneration. In the prior art, the two-phase absorbent meets the requirements of low-energy capture process by virtue of the above characteristics. Nevertheless, the traditional two-phase absorbent still faces problems in practical applications, such as the high viscosity of the rich phase or the solid phase is difficult to regenerate, and the amine is easy to volatilize and degrade. Summary of the invention

[0008] The purpose of the present invention is to overcome the defects of high regeneration energy consumption of traditional aqueous chemical absorbents, solve the defects of high rich liquid viscosity, insufficient absorption capacity and high regeneration energy consumption of dual-phase absorbents, and provide a new type of ionic liquid phase conversion driven absorbent, capture device and capture process for carbon dioxide capture.

[0009] To achieve the above object, the present invention adopts the following technical solution: A CO2 capture absorbent, comprising the following components in mass fractions: Proton type ionic liquid 20%~50%, Phase inversion driver 20%~50%, Water 20%~40%; The phase inversion driving agent is one of N,N-dimethylformamide, N-methylpyrrolidone, pentamethyldiethyltriamine, tetramethylethylenediamine, tetramethylbutylenediamine, tetramethylhexanediamine or dimethylpiperazine, or a mixture of several thereof.

[0010] Preferably, the CO2 capture absorbent comprises the following components in mass fractions: Proton type ionic liquid 30%~40%, Phase inversion driver 30%~40%, Water 20%~40%.

[0011] Preferably, the volume ratio of the proton type ionic liquid to the phase conversion driving agent is 1.4 to 4: 1. During absorption, as protons are transferred, the two phases gradually merge into one phase.

[0012] Preferably, the proton-type ionic liquid is composed of a proton acceptor and a proton donor, the proton acceptor is one or both of organic polyamines or piperazine compounds, and the proton donor is one or both of organic acids or inorganic acids.

[0013] Preferably, the organic polyamine is one or more of N,N-dimethyl-1,3-propylenediamine, ethylenediamine, N,N-dimethyl-1,4-butanediamine or N,N-dimethyl-1,6-hexanediamine.

[0014] Preferably, the piperazine compound is one or more of N-methylpiperazine, N-ethylpiperazine or hydroxyethylpiperazine.

[0015] Preferably, the organic acid is one or more of acetic acid, propionic acid, butyric acid, citric acid, succinic acid or adipic acid.

[0016] Preferably, the inorganic acid is any one or both of hydrochloric acid and sulfuric acid.

[0017] The second object of the present invention is to provide a CO2 capture and regeneration device, comprising an absorption tower and a regeneration tower, wherein the rich liquid outlet of the absorption tower is connected to the upper part of the regeneration tower, a downwardly contracting draft tube is provided in the lower part of the regeneration tower, and the bottom of the regeneration tower is connected to the upper part of the draft tube through a reboiler. The bottom end of the guide tube is surrounded by a phase separation groove, which is an annular groove opening upward, the outer wall of which is the inner wall of the absorption tower, the bottom end of the guide tube is lower than the top of the phase separation groove, a phase conversion driving agent outlet is arranged in the phase separation groove, and a gap is left between the top of the guide tube and the inner wall of the absorption tower. The gap can maintain the gas phase balance between the phase separation groove and the bottom of the regeneration tower.

[0018] Furthermore, the guide tube is funnel-shaped, the cone angle of the conical part of the funnel is 130°~170°, preferably 150°~162°, the diameter of the neck of the funnel is 0.1D~0.3D, the length of the neck of the funnel is 0.8~1.5D, the neck of the funnel is 0.5D~1.5D away from the bottom of the regeneration tower, and D is the inner diameter of the regeneration tower.

[0019] Furthermore, the inner diameter of the phase separation tank is 0.7D~0.95D, the top of the phase separation tank is 0.3D~0.5D higher than the bottom of the guide tube, the bottom of the phase separation tank is 0.05~0.2D away from the bottom of the regeneration tower, and D is the inner diameter of the regeneration tower. During the regeneration process, the regeneration liquid enters the phase separation tank through the guide tube, separates into phases in the phase separation tank, and the light phase flows into the phase conversion driving agent tank through the phase separation tank.

[0020] Furthermore, the capture and regeneration device also includes a heat exchanger and a mixer. The rich liquid outlet of the absorption tower is connected to the upper part of the regeneration tower through the heat exchanger, and the bottom of the regeneration tower is connected to the upper part of the absorption tower through the mixer and the heat exchanger in sequence. The inlet of the gas to be absorbed is arranged at the lower part of the absorption tower, and the phase inversion driving agent outlet is connected to the mixer.

[0021] During the regeneration process, the rich liquid enters the upper part of the regeneration tower and is then regenerated in the regeneration tower. The two-phase lean liquid obtained by regeneration is sent to the phase separation tank at the lower part of the tower through the guide tube. The light phase phase inversion driving agent is transported to the mixer from the phase inversion driving agent outlet. Part of the proton ion liquid aqueous solution at the bottom is sent to the reboiler for heating, and the rest is sent to the mixer to be mixed with the phase inversion driving agent and sent to the absorption tower as the lean liquid.

[0022] A phase separation structure is arranged at the lower part of the regeneration tower, and a pump is used to quantitatively extract the phase conversion driving agent. The reboiler only heats the proton ion liquid aqueous solution to provide regeneration heat.

[0023] The third object of the present invention is to provide a CO2 capture process, comprising: The gas to be absorbed is brought into contact with the CO2 capture absorbent, so that the CO2 capture absorbent absorbs CO2 in the gas to be absorbed, and the absorption temperature is 10-60°C.

[0024] Preferably, the pressure of the gas to be absorbed is 100-200 kPa.

[0025] Preferably, the CO2 capture process further comprises an absorbent regeneration step after the absorption is completed, and the temperature of the regeneration step is 80~120°C and the pressure is 80~300kPa.

[0026] Preferably, the gas to be absorbed is flue gas, natural gas, shift gas or synthesis gas.

[0027] The gas to be absorbed is brought into contact with the absorbent of the present invention, and the carbon dioxide in the gas to be absorbed is absorbed into the solution. The initial two phases are mixed into one phase due to the enhanced absorption. During the process of the rich liquid being heated and regenerated to restore into two phases, the carbon dioxide is desorbed faster due to the equilibrium driving force.

[0028] The phase-inversion driven absorbent used in the present invention can ensure high carbon dioxide absorption capacity while improving the regeneration efficiency of carbon dioxide, maintaining high circulation capacity, and thus reducing regeneration energy consumption, and has good application prospects in the field of large-scale flue gas capture. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is a diagram showing the changes in the appearance of the system during the absorption and desorption process in Example 1.

[0030] Figure 2 Schematic diagram of the CO2 capture and regeneration device.

[0031] Figure 3 Schematic diagram of the regeneration tower structure.

[0032] Figure 4 The regeneration efficiency of the ethanolamine aqueous solution is compared with that of the absorbent in Example 1 of the present invention.

[0033] Figure 5 The figure is a comparison of the regeneration energy consumption of the ethanolamine aqueous solution and the absorbent in Example 1 of the present invention.

[0034] Figure 6 The figure shows the viscosity comparison of the absorbent of Example 4 before and after absorption.

[0035] Figure 7 Comparison of CO2 loading of absorbents made from protic ionic liquids obtained by reacting N-ethylpiperazine with different acids in Example 5.

[0036] Figure 8 This is the CO2 equilibrium absorption curve of the absorbent in Example 6 at different temperatures.

[0037] Fig. 9 The absorption rate changes of the absorbent with different ionic liquid concentrations in Example 7.

[0038] in Figure 2-3 Among them, 1-1 is a guide tube, 1-2 is a reboiler, 1-3 is a phase separation tank, 1-4 is a mixer, 1-5 is a packing section, 1-6 is an absorption tower, 1-7 is a heat exchanger, and 1-8 is a regeneration tower. DETAILED DESCRIPTION

[0039] The present invention is illustrated by the following examples, but the present invention is not limited to the following examples. Without departing from the scope of the above-mentioned purpose, changes and implementations are included in the technical scope of the present invention.

[0040] like Figure 2~3 The CO2 capture and regeneration device shown includes an absorption tower and a regeneration tower, wherein the rich liquid outlet of the absorption tower is connected to the upper part of the regeneration tower, a downwardly contracting draft tube is provided in the lower part of the regeneration tower, the bottom of the regeneration tower is connected to the upper part of the draft tube through a reboiler, the bottom end of the draft tube is surrounded by a phase separation groove, the phase separation groove is an annular groove opening upward, the outer wall of the phase separation groove is the inner wall of the absorption tower, the bottom end of the draft tube is lower than the top of the phase separation groove, a phase conversion driving agent outlet is provided in the phase separation groove, and a gap is left between the top of the draft tube and the inner wall of the absorption tower. The gap can maintain the gas phase equilibrium between the phase separation groove and the bottom of the regeneration tower.

[0041] The guide tube is funnel-shaped, the cone angle of the conical part of the funnel is 130°~170°, preferably 150°~162°, the diameter of the neck of the funnel is 0.1D~0.3D, the length of the neck of the funnel is 0.8~1.5D, the neck of the funnel is 0.5D~1.5D away from the bottom of the regeneration tower, and D is the inner diameter of the regeneration tower.

[0042] The inner diameter of the phase separation tank is 0.7D~0.95D, the top of the phase separation tank is 0.3D~0.5D higher than the bottom of the guide tube, the bottom of the phase separation tank is 0.05~0.2D away from the bottom of the regeneration tower, and D is the inner diameter of the regeneration tower. During the regeneration process, the regeneration liquid enters the phase separation tank through the guide tube, separates into phases in the phase separation tank, and the light phase flows into the phase conversion driving agent tank through the phase separation tank.

[0043] The capture and regeneration device also includes a heat exchanger and a mixer. The rich liquid outlet of the absorption tower is connected to the upper part of the regeneration tower through the heat exchanger, and the bottom of the regeneration tower is connected to the upper part of the absorption tower through the mixer and the heat exchanger in sequence. The inlet of the gas to be absorbed is arranged at the lower part of the absorption tower, and the phase inversion driving agent outlet is connected to the mixer. Example 1

[0044] An appropriate amount of N-ethylpiperazine reacts with propionic acid in an equimolar amount in a reactor, the temperature of which is controlled by a cold water bath. During the preparation process, propionic acid is slowly added and the reaction mixture is stirred for 24 hours to obtain a protic ionic liquid.

[0045] 300g of the obtained proton ionic liquid, 300g of N-methylpyrrolidone and 400g of water were prepared into an absorbent. Using the above-mentioned device, the temperature of the absorption tower was controlled to 40°C, and flue gas containing 20% ​​CO2 was slowly introduced at a gas volume of 400kg / h, a pressure of 1.1bar, and an absorbent input of 1000kg / h.

[0046] After the absorption was completed, the rich liquid was taken and the CO2 loading was calculated to be 0.08 g / g, and the molar ratio of CO2 to ionic liquid was 0.89.

[0047] The absorbed rich liquid is sent to the regeneration tower, the regeneration temperature is 100℃, the regeneration rate is 92%, and the regeneration energy consumption is 2.1GJ / tCO2. The appearance changes of the system during absorption and desorption are as follows: Figure 1 shown.

[0048] As a comparison, the prepared ionic liquid was directly used for the absorption of flue gas containing 20% ​​CO2 under the same conditions, and the molar ratio of CO2 to ionic liquid was measured to be 0.38. The rich liquid after absorption was regenerated at 100°C, with a regeneration rate of 72.3% and a regeneration energy consumption of 3.78 / tCO2.

[0049] Taking ethanolamine aqueous solution as a comparison, under the same conditions, it was used for the absorption and regeneration of flue gas containing 20% ​​CO2. The comparison of regeneration efficiency is as follows: Figure 4 As shown in Figure 2, the energy consumption is Figure 5 shown. Example 2

[0050] An appropriate amount of N,N-dimethylpropylenediamine reacts with citric acid in an equimolar ratio in a reactor, and the temperature is controlled by a cold water bath. During the preparation process, citric acid is slowly added and the reaction mixture is stirred for 24 hours to obtain a proton ionic liquid.

[0051] 400g of the obtained proton ionic liquid, 250g of pentamethyldiethyltriamine and 350g of water were prepared into an absorbent. Using the above-mentioned device, the temperature of the absorption tower was controlled to 40°C, and flue gas containing 20% ​​CO2 was slowly introduced with a gas volume of 200kg / h, a pressure of 1.1bar, and an absorbent input of 500kg / h.

[0052] After the absorption was completed, the rich liquid was taken and the CO2 loading was calculated to be 0.087 g / g, and the molar ratio of CO2 to ionic liquid was 0.86.

[0053] The absorbed rich liquid is sent to the regeneration tower, the regeneration temperature is 100°C, the regeneration rate is 92.5%, and the regeneration energy consumption is 2.06GJ / t CO2.

[0054] As a comparison, the prepared ionic liquid was directly used for the absorption of flue gas containing 20% ​​CO2 under the same conditions, and the molar ratio of CO2 to ionic liquid was measured to be 0.35. The rich liquid after absorption was regenerated at 100°C, with a regeneration rate of 75.2 and a regeneration energy consumption of 3.92GJ / tCO2. Example 3

[0055] Appropriate amounts of hydroxyethylpiperazine / adipic acid and N,N-dimethyl-1,3-propylenediamine / butyric acid were reacted in equal moles in a reactor, and the temperature was controlled by a cold water bath. During the preparation process, the acid was slowly added and the reaction mixture was stirred for 24 hours to obtain two protic ionic liquids.

[0056] 350g of the two obtained proton ionic liquids (mass ratio 1:2), 300g of tetramethylbutanediamine and 350g of water were prepared into an absorbent. Using the above-mentioned device, the temperature of the absorption tower was controlled at 40°C, and flue gas containing 20% ​​CO2 was slowly introduced with a gas volume of 300kg / h, a pressure of 1.1bar, and an absorbent input of 600kg / h.

[0057] After the absorption was completed, the rich liquid after absorption was taken, and the CO2 loading was calculated to be 0.092 g / g, and the molar ratio of CO2 to ionic liquid was 0.91.

[0058] The absorbed rich liquid is sent to the regeneration tower, the regeneration temperature is 105℃, the regeneration rate is 90.6%, and the regeneration energy consumption is 2.02GJ / t CO2.

[0059] As a comparison, the two prepared ionic liquids (mass ratio 1:2) were directly used for the absorption of flue gas containing 20% ​​CO2 under the same conditions, and the molar ratio of CO2 to ionic liquid was measured to be 0.31. After the absorption was completed, the rich liquid was regenerated at 105°C, the regeneration rate was 70.3, and the regeneration energy consumption was 3.56GJ / tCO2. Example 4

[0060] The proton ionic liquid was obtained by reacting equimolar N,N-dimethylpropylenediamine with acetic acid, and then mixed with tetramethylbutylene diamine and water to form a mixed absorbent, wherein the ionic liquid content was 30%, the tetramethylhexane diamine content was 30%, and the water content was 40%. At 25°C, when the initial partial pressure of carbon dioxide was 100 kPa, the molar ratio of CO2 to ionic liquid was 1.8. The viscosity of the absorption system before and after absorption was as follows: Figure 6 shown. Example 5

[0061] N-ethylpiperazine was prepared into ionic liquids with propionic acid, butyric acid, citric acid, succinic acid and adipic acid respectively, and tetramethylhexamethylenediamine was used as a phase conversion agent. The absorbent was prepared according to the method of Example 1, and the absorption was carried out at 25°C and the initial partial pressure of carbon dioxide was 100 kPa. The obtained CO2 loading amount was as follows: Figure 7 shown. Example 6

[0062] The proton ionic liquid was obtained by reacting equimolar N,N-dimethylpropylenediamine with acetic acid, and was configured into an absorbent according to the method of Example 1 to obtain a CO2 equilibrium absorption curve with an absorption temperature of 288-313K and a CO2 equilibrium pressure of 0-3.0 bar, as shown in FIG. Figure 8 shown. Example 7

[0063] The proton ionic liquid was obtained by reacting equimolar N,N-dimethyl-1,4-butanediamine with propionic acid, and tetramethylhexanediamine was used as the phase inversion driver. The CO2 absorbent was prepared according to the method of Example 1. The water content was fixed at 40%. The concentration of the ionic liquid ranged from 0 to 60%. At 25°C and an initial partial pressure of carbon dioxide of 100 kPa, the absorption rate varied as follows: Fig. 9 shown. Example 8

[0064] An equimolar amount of N,N-dimethyl-1,6-hexanediamine was reacted with hydrochloric acid to obtain a proton ionic liquid, dimethylpiperazine was used as a phase inversion driver, and was configured into a CO2 absorbent according to the method of Example 1. The fixed ionic liquid content was 20%, and the water contents were 20%, 30%, and 40%, respectively. At 10°C, when the initial partial pressure of carbon dioxide was 200 kPa, CO2 was absorbed, and the calculated CO2 loads were 0.12 g / g, 0.18 g / g, and 0.25 g / g, respectively. Example 9

[0065] Equimolar amounts of ethylenediamine and sulfuric acid were reacted to obtain a proton ionic liquid, with tetramethylethylenediamine as a phase inversion driver. The proton ionic liquid was prepared according to the method of Example 1 to form a CO2 absorbent. The absorbents were prepared with an ionic liquid content of 40%, a phase inversion driver content of 20%, a water content of 40%, and an ionic liquid content of 30%, a phase inversion driver content of 50%, and a water content of 20%. At 10°C, when the initial partial pressure of carbon dioxide was 200 kPa, CO2 was absorbed, and the calculated CO2 loads were 0.21 g / g and 0.16 g / g, respectively.

Claims

1. A CO2 capture absorbent, characterized in that: The components include the following mass fractions: Proton type ionic liquid 20%~50%, Phase inversion driver 20%~50%, Water 20%~40%; The phase inversion driving agent is one of N,N-dimethylformamide, N-methylpyrrolidone, pentamethyldiethyltriamine, tetramethylethylenediamine, tetramethylbutylenediamine, tetramethylhexanediamine or dimethylpiperazine, or a mixture of several thereof.

2. The CO2 capture absorbent according to claim 1, characterized in that: The CO2 capture absorbent comprises the following components in mass fraction: Proton type ionic liquid 30%~40%, Phase inversion driver 30%~40%, Water 20%~40%.

3. The CO2 capture absorbent according to claim 1 or 2, characterized in that: The volume ratio of the proton type ionic liquid to the phase inversion driving agent is 1.4-4:

1.

4. The CO2 capture absorbent according to claim 1, characterized in that The proton-type ionic liquid is composed of a proton acceptor and a proton donor, wherein the proton acceptor is one or both of an organic polyamine or a piperazine compound, and the proton donor is one or both of an organic acid or an inorganic acid; preferably, the organic polyamine is one or more of N,N-dimethyl-1,3-propylenediamine, ethylenediamine, N,N-dimethyl-1,4-butanediamine or N,N-dimethyl-1,6-hexanediamine; preferably, the piperazine compound is one or more of N-methylpiperazine, N-ethylpiperazine or hydroxyethylpiperazine; preferably, the organic acid is one or more of acetic acid, propionic acid, butyric acid, citric acid, succinic acid or adipic acid; preferably, the inorganic acid is any one or both of hydrochloric acid or sulfuric acid.

5. A CO2 capture and regeneration device, characterized in that: It includes an absorption tower and a regeneration tower, wherein the rich liquid outlet of the absorption tower is connected to the upper part of the regeneration tower, a guide tube with a downwardly reduced diameter is arranged in the lower part of the regeneration tower, and the bottom of the regeneration tower is connected to the upper part of the guide tube through a reboiler. The bottom end of the guide tube is surrounded by a phase separation groove, which is an annular groove opening upward, the outer wall of which is the inner wall of the absorption tower, the bottom end of the guide tube is lower than the top of the phase separation groove, a phase conversion driving agent outlet is arranged in the phase separation groove, and a gap is left between the top of the guide tube and the inner wall of the absorption tower. The gap can maintain the gas phase balance between the phase separation groove and the bottom of the regeneration tower.

6. The CO2 capture and regeneration device according to claim 5, characterized in that: The guide tube is funnel-shaped, the cone angle of the conical part of the funnel is 130°~170°, preferably 150°~162°, the diameter of the neck of the funnel is 0.1D~0.3D, the length of the neck of the funnel is 0.8~1.5D, the neck of the funnel is 0.5D~1.5D away from the bottom of the regeneration tower, and D is the inner diameter of the regeneration tower.

7. The CO2 capture and regeneration device according to claim 5, characterized in that: The capture and regeneration device also includes a heat exchanger and a mixer. The rich liquid outlet of the absorption tower is connected to the upper part of the regeneration tower through the heat exchanger, and the bottom of the regeneration tower is connected to the upper part of the absorption tower through the mixer and the heat exchanger in sequence. The inlet of the gas to be absorbed is arranged at the lower part of the absorption tower, and the phase inversion driving agent outlet is connected to the mixer.

8. A CO2 capture process, characterized in that: include: The gas to be absorbed is brought into contact with the CO2 capture absorbent, so that the CO2 capture absorbent absorbs CO2 in the gas to be absorbed, and the absorption temperature is 10-60°C; preferably, the gas to be absorbed is flue gas, natural gas, conversion gas or synthesis gas.

9. The CO2 capture process according to claim 8, characterized in that: The pressure of the gas to be absorbed is 100-200 kPa.

10. The CO2 capture process according to claim 8 or 9, characterized in that: The CO2 capture process also includes an absorbent regeneration step after the absorption is completed, and the temperature of the regeneration step is 80~120°C and the pressure is 80~300kPa.

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