A method for low-energy capture of carbon dioxide in air by solid-phase liquid membrane method

Abstract

The present invention discloses a method for low-energy capture of carbon dioxide in air by the solid-phase liquid membrane method, which includes: impregnating an absorbent liquid (lean liquid) on a high specific surface area porous solid-phase material to form a liquid membrane layer, and then fully exposing it in space. Low-concentration CO2 in the air rapidly mass-transfers to the liquid membrane surface through the concentration difference to achieve concentrated adsorption; when the liquid membrane is saturated with CO2 adsorption, it is washed by circulating clear water, so that the liquid membrane with saturated surface adsorption falls off from the solid phase surface to obtain a regenerated liquid (rich liquid) rich in CO2; the lean liquid is repeatedly rinsed to make the lean liquid form a film on the solid phase surface again for the next round of adsorption; the collected rich liquid is heated and desorbed for regeneration to obtain high-purity CO2 gas for storage and subsequent utilization. The air CO2 capture method proposed by the present invention combines the advantages of solid-phase and liquid-phase CO2 absorption. It not only has high carbon capture efficiency and low energy consumption, but also has simple operation and is easy to be popularized on a large scale, and has good application prospects.

Description

Technical Field

[0001] The present invention relates to the technical field of direct air capture of carbon dioxide (CO 2 ), and particularly to a method for low-energy consumption capture of carbon dioxide in air by a solid-phase liquid membrane method. Background Art

[0002] As the main component of greenhouse gases, the increase in CO 2 emissions has exacerbated global warming. Therefore, carbon neutralization technologies such as CO 2 emission reduction to delay global warming have received increasing attention. Direct air capture of CO 2 (Direct air capture, DAC) is a technology for removing CO 2 from ambient air through an engineering system, which can effectively reduce the concentration of CO 2 in the atmosphere. However, for capturing CO 2 with a concentration above 90% from 300 - 400 ppm in air, the energy consumption and cost of its engineering system have always been insurmountable obstacles and the main problems for the current commercialization of DAC.

[0003] Reducing the energy consumption and cost of DAC capture is the current direction of efforts in the scientific and industrial communities. Liquid-phase and solid-phase chemical absorption methods have always been the mainstream technologies reported for DAC and are widely used by the world's leading DAC institutions. Among them, the liquid-phase absorption method is a technology evolved from the capture of high-concentration CO 2 in flue gas. Liquid organic amines and caustic alkalis are used as absorbents, and the absorption is achieved by the chemical reaction mechanism of amino and hydroxyl groups with CO 2 to form carbamates and carbonates. Among them, the carbamate intermediate can rapidly release CO 2 under the thermal action at 100 - 120°C, thereby obtaining high-concentration CO 2 and regenerating the absorbent. After years of technological development, the current energy consumption of liquid-phase absorption technology in high-concentration CO 2 in flue gas can be ≤2.4 GJ / tCO 2 , and the cost can be ≤250 yuan (RMB) / tCO 2 . However, in the capture of air CO 2 , the concentration of CO 2 is only 300 - 400 ppm, the concentration driving force is small, and gas-liquid mass transfer becomes the rate-limiting step, resulting in low absorption efficiency. In addition, the low concentration of gas-phase CO 2 also leads to a sharp decrease in the equilibrium absorption capacity of the absorbent and a significant increase in the energy consumption for absorbent desorption and regeneration. Therefore, how to improve the absorption rate and equilibrium absorption capacity of liquid-phase absorbents for low-concentration CO 2 in air is the key point to be broken through in liquid-phase absorption technology in the future.

[0004] To improve the absorption rate and capacity of air CO 2 Absorption rate and capacity, researchers will adopt forms such as increasing fillers (CN116615279A, CN116887913A), atomizing absorption droplets (CN116173711A), etc. to improve the gas-liquid mass transfer rate. Although these technologies are beneficial to the improvement of mass transfer, they also increase additional energy consumption. The porous solid-phase absorption technology proposes a new idea of high absorption efficiency, introducing amino groups into the pores of porous materials such as silica gel (J.Energy Chem, 2022, 75:494-503), molecular sieve (CN 114522505A), resin (CN 113786818 A), etc. Utilizing the large specific surface area of the micropores of these porous materials, the probability of contact between amino groups and low-concentration CO 2 Is greatly increased, making its absorption efficiency rise significantly. In addition, the nanopore structure of the porous material has a physical adsorption enrichment effect, which can enrich low-concentration CO in the air 2 In the pores, which also improves the unit absorption capacity and better solves the problems of the absorption rate and absorption capacity of low-concentration CO in the air 2 Therefore, most DAC companies in the world currently use solid amines to capture air CO 2 , such as climeworks (CN 115803096 A, CN 115916379 A), hydro cell (CN 116157189A), Linhe Climate Technology (CN 115475664A), etc.

[0005] Although the solid-phase absorption method solves the absorption problem, in terms of CO 2 Desorption and regeneration, the solid-phase absorption method is not as energy-efficient as the liquid-phase absorption method. The solid-phase absorption method currently generally uses steam desorption technology, heating the solid adsorption material with steam as the heat source to desorb the adsorbed CO 2 Quickly desorb, and the desorbed CO 2 And steam pass through the condensation device together to separate CO 2 And steam, so as to obtain high-concentration CO 2 (CN 112312993 A). However, the desorption heating and cooling adsorption of the solid-phase absorption material consume a large amount of energy, resulting in high desorption energy consumption of the solid-phase absorption method for CO 2 , and the residual water molecules in the pores will also affect the adsorption of CO 2 Efficiency. More importantly, due to the existence of dead volume in the space of the solid-phase absorption technology, the purity of the desorbed CO 2 Cannot reach more than 95%, which limits its resource utilization.

[0006] In summary, both the liquid-phase absorption method and the solid-phase adsorption method have their own advantages and disadvantages. The liquid-phase absorption technology has advantages in desorption and regeneration, while the solid-phase absorption method has advantages in absorption. If their respective advantages can be comprehensively utilized to develop a technology that combines the advantages of solid-phase absorption and liquid-phase desorption and regeneration, the commercialization process of DAC technology can be greatly promoted. Guided by this idea, this invention patent proposes a method for rapidly capturing carbon dioxide in the air by the solid-phase liquid membrane method, which has the advantages of fast adsorption rate, good stability, low regeneration energy consumption, low cost, etc., and has broad application prospects. Summary of the Invention

[0007] In view of the above technical problems existing in the prior art, in order to reduce the energy consumption and cost of the existing technology for directly capturing CO in the air, the object of the present invention is to provide a method for low-energy consumption capturing of carbon dioxide in the air by the solid-phase liquid membrane method. The present invention rapidly forms an absorption layer liquid membrane on the high specific surface of a porous solid material, rapidly absorbs low-concentration carbon dioxide in the air through pore enrichment and surface chemical adsorption sites, and at the same time improves the CO content in the rich liquid and reduces the regeneration energy consumption of thermal desorption of CO in the rich liquid through liquid membrane circulation washing. 2 The technical solution adopted by the present invention is as follows: 2 A method for low-energy consumption capturing of carbon dioxide in the air by the solid-phase liquid membrane method, the method comprising the following steps: 2 1) Solid-phase liquid membrane film-forming stage: Mix a high-boiling-point CO liquid-phase absorbent with water to prepare an absorbent solution, denoted as lean liquid; the lean liquid is impregnated on a porous solid material with a high specific surface for the first time to form a liquid membrane layer, and the mass ratio of the porous solid material to the lean liquid is 1:1 to 10, obtaining a solid-phase adsorbent loaded with a liquid membrane.

[0008] 2) Rapid adsorption stage: The solid-phase adsorbent loaded with the liquid membrane is fully exposed to the air and contacted with flowing air. The liquid membrane adsorption layer with a high specific surface captures a large amount of low-concentration carbon dioxide in the air in a short time through pore enrichment and concentration difference mass transfer until the liquid membrane on the surface of the solid-phase adsorbent is saturated with CO adsorption.

[0009] 3) Adsorption layer regeneration stage: After adsorption is completed, a certain amount of clear water is used to circulate and wash the solid-phase adsorbent to obtain an absorbent containing CO, denoted as rich liquid. Subsequently, the lean liquid (or the lean liquid with a re-prepared concentration after regeneration) is used to circulate and wash the solid-phase adsorbent to re-form a film, and the next round of air CO adsorption is carried out. After adsorption is completed, the rich liquid is still used for circulating washing until the CO in the rich liquid

[0010] 1) Solid-phase liquid membrane film-forming stage: Mix a high-boiling-point CO liquid-phase absorbent with water to prepare an absorbent solution, denoted as lean liquid; the lean liquid is impregnated on a porous solid material with a high specific surface for the first time to form a liquid membrane layer, and the mass ratio of the porous solid material to the lean liquid is 1:1 to 10, obtaining a solid-phase adsorbent loaded with a liquid membrane. 2 2) Rapid adsorption stage: The solid-phase adsorbent loaded with the liquid membrane is fully exposed to the air and contacted with flowing air. The liquid membrane adsorption layer with a high specific surface captures a large amount of low-concentration carbon dioxide in the air in a short time through pore enrichment and concentration difference mass transfer until the liquid membrane on the surface of the solid-phase adsorbent is saturated with CO adsorption.

[0011] 3) Adsorption layer regeneration stage: After adsorption is completed, a certain amount of clear water is used to circulate and wash the solid-phase adsorbent to obtain an absorbent containing CO, denoted as rich liquid. Subsequently, the lean liquid (or the lean liquid with a re-prepared concentration after regeneration) is used to circulate and wash the solid-phase adsorbent to re-form a film, and the next round of air CO adsorption is carried out. After adsorption is completed, the rich liquid is still used for circulating washing until the CO in the rich liquid 2 2) Rapid adsorption stage: The solid-phase adsorbent loaded with the liquid membrane is fully exposed to the air and contacted with flowing air. The liquid membrane adsorption layer with a high specific surface captures a large amount of low-concentration carbon dioxide in the air in a short time through pore enrichment and concentration difference mass transfer until the liquid membrane on the surface of the solid-phase adsorbent is saturated with CO adsorption.

[0012] 3) Adsorption layer regeneration stage: After adsorption is completed, a certain amount of clear water is used to circulate and wash the solid-phase adsorbent to obtain an absorbent containing CO, denoted as rich liquid. Subsequently, the lean liquid (or the lean liquid with a re-prepared concentration after regeneration) is used to circulate and wash the solid-phase adsorbent to re-form a film, and the next round of air CO adsorption is carried out. After adsorption is completed, the rich liquid is still used for circulating washing until the CO in the rich liquid 2 3) Adsorption layer regeneration stage: After adsorption is completed, a certain amount of clear water is used to circulate and wash the solid-phase adsorbent to obtain an absorbent containing CO, denoted as rich liquid. Subsequently, the lean liquid (or the lean liquid with a re-prepared concentration after regeneration) is used to circulate and wash the solid-phase adsorbent to re-form a film, and the next round of air CO adsorption is carried out. After adsorption is completed, the rich liquid is still used for circulating washing until the CO in the rich liquid 2 3) Adsorption layer regeneration stage: After adsorption is completed, a certain amount of clear water is used to circulate and wash the solid-phase adsorbent to obtain an absorbent containing CO, denoted as rich liquid. Subsequently, the lean liquid (or the lean liquid with a re-prepared concentration after regeneration) is used to circulate and wash the solid-phase adsorbent to re-form a film, and the next round of air CO adsorption is carried out. After adsorption is completed, the rich liquid is still used for circulating washing until the CO in the rich liquid 2The adsorption amount reaches the concentration required for regeneration, and it is collected for subsequent regeneration.

[0013] 4) Rich liquid regeneration stage: In the stripping tower, the high-concentration rich liquid collected by circulating washing is centrally heated and regenerated to obtain high-purity CO 2 gas product. After the rich liquid is regenerated, it is reused in the liquid membrane washing and collection stage, or after the rich liquid is regenerated, it forms a lean liquid at the equilibrium concentration with the medium-level water and is used to re-enter the film-forming stage.

[0014] Furthermore, the high-boiling-point CO 2 in the liquid-phase absorbent in step 1) includes but is not limited to at least one of organic amines such as triethylenetetramine, tetraethylenepentamine, and polyethyleneimine, or includes but is not limited to ionic liquids prepared by combining at least one of cation donors such as imidazole and pyridine with at least one of anion donors such as 1,5-diazabicyclo[4.3.0]non-5-ene (DBN) and tetraethylenepentamine.

[0015] Furthermore, the preparation method of the ionic liquid is: mixing the cation donor and the anion donor in a molar ratio of 1.5 - 3:1, and stirring at 70 - 80 °C for 1 - 3 hours.

[0016] Furthermore, the porous solid material is at least one of activated carbon particles, activated carbon fibers, and macroporous resins, and its specific surface area is above 500 m 2 / g, preferably above 1000 m 2 / g.

[0017] Furthermore, the high-boiling-point CO 2 in the liquid-phase absorbent in step 1) has a mass ratio of 1:0.1 - 5 to water, preferably 1:4 - 5, and the mass ratio of the porous solid material to the lean liquid is 1:9 - 10. When initially forming the film in step 1), the porous solid material does not absorb CO 2 components, so only a small amount of solution is needed for film formation, so the mass ratio of the porous solid material to the lean liquid is 1:9 - 10.

[0018] Furthermore, the adsorption time in step 2) is 1 - 10 h, preferably 2 - 4 h.

[0019] Furthermore, the mass ratio of the clear water used to wash the liquid membrane in step 3) or the rich liquid used to wash the liquid membrane subsequently to the porous solid material is 20 - 50:1, preferably 30:1.

[0020] Furthermore, the mass ratio of the lean liquid for circulating rinsing used for re-film formation in step 3) to the porous solid material is 20 - 50:1, preferably 40:1. When re-forming the film in step 3), since part of the CO 2The rich liquid of the component, so an excessive amount of lean liquid is required to bring the CO brought by the residual rich liquid 2 component concentration is reduced as much as possible, so a relatively large amount of circulating lean liquid is used.

[0021] Further, in step 3), the CO in the rich liquid 2 adsorption amount reaches the required concentration for regeneration of 1.0 mol / kg or more, preferably 1.5 mol / kg or more.

[0022] Further, in step 4), the regeneration temperature of the rich liquid is 80-130 °C, preferably 90-100 °C. When the regeneration temperature is less than 100 °C and does not reach the boiling point temperature of water, there is little water loss during heating regeneration, and the rich liquid after regeneration can be reused for the liquid film washing and collection stage to perform cyclic leaching on the solid phase adsorbent saturated with CO 2 adsorption. When the regeneration temperature approaches 100 °C and above and reaches the boiling point temperature of water, a large amount of water evaporates during heating regeneration and carries CO 2 to escape. The evaporated mixed vapor is condensed to obtain condensed water and high-purity CO 2 gas product. At this time, the absorbent concentration in the rich liquid after regeneration is greatly concentrated, and clear water is added to it to balance the concentration to form lean liquid, which can be used to re-enter the film-forming stage.

[0023] Further, the concentration of low-concentration CO in the air 2 is 400 ppm or less, preferably 300-400 ppm.

[0024] The present invention also discloses an apparatus adopted by the method of the present invention, including a CO 2 adsorption device, a rich liquid circulation pump, a rich liquid pool, a lean liquid circulation pump, a lean liquid pool and a desorption tower. The CO 2 adsorption device is used to fixedly load a porous solid material.

[0025] In the impregnation film-forming stage, the lean liquid circulation pump is used to transport the lean liquid in the lean liquid pool to the CO 2 adsorption device to perform drip film-forming on the porous solid material. The dripping lean liquid is collected in the lean liquid pool to form a cycle until the lean liquid is completely film-formed on the porous solid material.

[0026] In the first liquid film washing and collection stage, clear water is first added to the rich liquid pool. The rich liquid circulation pump is used to transport the rich liquid in the rich liquid pool to the CO 2 adsorption device to perform drip washing on the porous solid material. The dripping rich liquid is collected in the rich liquid pool to form a cycle until the liquid film is eluted from the surface of the porous solid material; in the subsequent liquid film washing and collection stage, the rich liquid in the rich liquid pool is still used for cyclic leaching until the CO in the rich liquid 2 adsorption amount reaches the required concentration for regeneration and is collected for subsequent regeneration.

[0027] During the rich liquid regeneration stage, the collected rich liquid enters the stripping column for heating and desorption regeneration. Part of the water evaporates and vaporizes, carrying CO 2 gas to escape. The escaping mixed vapor is condensed to condense the water in it, and high-purity CO 2 gas can be obtained for storage and subsequent utilization.

[0028] Furthermore, the CO 2 adsorption device includes a supporting main pipe, a liquid delivery main pipe arranged inside it, and a number of shunt pipes evenly spaced along the circumference on the upper side of its outer part. The outlet of the liquid delivery main pipe is connected to each shunt pipe. A stainless steel mesh frame is fixedly arranged below each shunt pipe. A number of liquid dripping holes are evenly arranged along the length direction of the shunt pipe near the stainless steel mesh frame at the bottom. Two stainless steel mesh sheets and a porous solid phase material clamped between them are installed on the stainless steel mesh frame. A reflux trough is arranged below the stainless steel mesh frame and fixed to the supporting main pipe. A liquid collecting trough is also arranged on the lower side of the supporting main pipe. Each reflux trough inclines towards the liquid collecting trough and is connected to the liquid collecting trough through a liquid outlet pipe. A trough liquid outlet is arranged at the bottom of the liquid collecting trough. The trough liquid outlet is divided into two paths and connected to the rich liquid pool and the lean liquid pool through pipelines respectively. The inlet of the liquid delivery main pipe is divided into two paths. One path is connected to the rich liquid pool through a rich liquid circulation pump by a pipeline, and the other path is connected to the lean liquid pool through a lean liquid circulation pump by a pipeline. Control valves are arranged on the corresponding pipelines.

[0029] Compared with the prior art, the present invention has the following advantages by quickly forming a large-area liquid film on the high specific surface porous solid phase material and subsequent use of rich liquid circulation washing:

[0030] (1) Compared with the traditional liquid phase absorption method, ① a large amount of the adsorption solution of the present invention is distributed in the pores of the porous material. After partial water volatilizes (when absorbing CO 2 in flowing air, a small amount of water will be carried away by the air flow), a thin liquid film of the absorbent is formed in the pores. The contact area with air is large, so the mass transfer rate is high, and low-concentration CO 2 in the air can be quickly captured, and the thin layer adsorption effectively avoids the excessive viscosity of the absorption liquid affecting gas mass transfer. ② By circulating and enriching the rich liquid, the CO 2 concentration in the rich liquid is increased, thereby reducing the desorption energy consumption per unit CO 2 of the absorption liquid.

[0031] (2) Compared with the traditional solid phase adsorption method, ① the absorption liquid film generates rich liquid through washing, and heating and regenerating the rich liquid produces high-purity CO 2 product, avoiding the high energy consumption caused by the large amount of water vapor required for CO 2 desorption in the solid phase adsorption method. ② Regenerating in the form of the liquid phase rich liquid of the absorbent also overcomes the desorption of CO caused by the dead volume of the solid phase2 Problem of low concentration.

[0032] (3) In addition, since the technology of the present invention can obtain a high adsorption capacity at a relatively low wind speed, and even a high absorption efficiency can be obtained in a natural wind environment, a large amount of fan energy consumption is saved compared with traditional capture devices, the requirements for the device are low, and it can be miniaturized for decentralized capture and then centralized regeneration.

[0033] In summary, the present invention effectively combines the respective advantages of traditional liquid-phase and solid-phase adsorption methods, and creatively proposes a method for low-energy consumption capture of air carbon dioxide by a solid-phase liquid membrane method. While having the advantages of fast adsorption rate, high capacity, low regeneration energy consumption, and good stability, it can quickly absorb carbon dioxide in the air at different wind speeds, effectively reduce the additional energy consumption generated by the installed fan, and has low requirements for the site and high benefits. Description of the Drawings

[0034] Figure 1 It is a schematic flow structure diagram for the rapid capture of carbon dioxide in the air by the solid-phase liquid membrane method of the present invention;

[0035] Figure 2 It is for the present invention CO 2 Schematic diagram of the structure of the adsorption device;

[0036] Figure 3 It is the pore size distribution diagram of the porous solid material - activated carbon fiber.

[0037] Figure 4 It is the pore size distribution diagram of the porous solid material - activated carbon particles. Detailed Embodiments

[0038] The present invention will be further described below in conjunction with specific embodiments, but the protection scope of the present invention is not limited thereto.

[0039]

Embodiment

[0040] The device for low-energy consumption capture of carbon dioxide in the air by the solid-phase liquid membrane method of the present invention includes a CO 2 adsorption device, a rich liquid circulation pump, a rich liquid tank, a lean liquid circulation pump, a lean liquid tank, and a desorption tower. The CO 2 adsorption device is used for fixedly loading the porous solid material. The flow chart for quickly capturing carbon dioxide in the air by using the device of the present invention is shown in Figure 1 .

[0041] The CO 2 schematic diagram of the structure of the adsorption device is shown in Figure 2, including a support main pipe 1, through which an infusion main pipe is passed. The lower end inlet of the infusion main pipe passes through the lower end of the support main pipe 1 and is divided into two paths. One path is connected to a rich liquid pool through a rich liquid circulation pump by a pipeline, and the other path is connected to a lean liquid pool through a lean liquid circulation pump by a pipeline.

[0042] A number of shunt pipes 3 are evenly spaced along the circumference on the upper end side of the outer part of the support main pipe 1. The upper end outlet of the infusion main pipe passes through the upper end of the support main pipe 1 and is connected to a plurality of branches. The number of branches corresponds to the number of shunt pipes 3, and the two are connected in one-to-one correspondence. Figure 2 , on the upper part of one end of the shunt pipe 3 close to the support main pipe 1, a shunt pipe inlet 2 is provided. The shunt pipe inlet 2 is connected to the upper end outlet of the infusion main pipe through the corresponding branch.

[0043] A stainless steel mesh frame 5 is fixedly arranged below each shunt pipe 3. Two stainless steel mesh sheets are installed on the stainless steel mesh frame 5, and a porous solid phase material is clamped between the two stainless steel mesh sheets, thereby realizing the fixation of the porous solid phase material on the trapping device. A number of liquid dripping holes 4 are evenly arranged along the length direction of the bottom of the shunt pipe 3 close to the stainless steel mesh frame 5. The liquid droplets flowing out from the liquid dripping holes 4 can flow onto the two stainless steel mesh sheets on the stainless steel mesh frame 5 and the porous solid phase material clamped between them. Under the capillary action of the adsorption of the porous solid phase material, the liquid can uniformly diffuse on the porous solid phase material. A reflux groove 6 is provided below each stainless steel mesh frame 5. The reflux groove 6 is fixed on the support main pipe 1. A liquid collecting groove 7 is also provided on the lower end side of the support main pipe 1. Each reflux groove 6 inclines towards the liquid collecting groove 7 and is connected to the liquid collecting groove 7 through a liquid outlet pipeline. The liquid droplets dripping from the porous solid phase material can enter the reflux groove 6. The inclined setting of the reflux groove 6 facilitates the collection of the liquid in it towards the liquid collecting groove 7. A groove liquid outlet 8 is provided at the bottom of the liquid collecting groove 7. The groove liquid outlet 8 is divided into two paths and is respectively connected to the rich liquid pool and the lean liquid pool by pipelines.

[0044] When the device of the present invention works, the porous solid phase material is placed on the trapping device (the trapping device includes a stainless steel mesh frame and two corresponding stainless steel mesh sheets). Subsequently, a certain amount of absorbent liquid (the mass ratio of absorbent to solvent = 1:4, denoted as lean liquid) is mixed evenly and then rinsed on the porous solid phase material fixed on the trapping device to obtain a solid phase adsorbent loaded with a liquid film. Subsequently, the solid phase adsorbent loaded with the liquid film is placed under a certain wind speed and adsorbed with CO at 293K for 2h. 2 . After the adsorption is completed, it is rinsed with circulating water, and the rinsing liquid flows into the rich liquid pool. Subsequently, first take a part of the above-prepared lean liquid to circulate and rinse the "solid phase adsorbent" and then flow into the lean liquid pool to supplement the consumption of film formation. Then, use the lean liquid to circulate and rinse the "solid phase adsorbent" to re-form a film for the next round of CO adsorption. 2 .

[0045] In the second round and subsequent adsorption processes, after the adsorption is completed, the rich liquid in the rich liquid pool is used to circulate and wash the "solid adsorbent" to increase the concentration of the rich liquid, and the eluent flows into the rich liquid pool. Subsequently, first, a part of the prepared lean liquid is used to circulate and wash the "solid adsorbent" and then flows into the lean liquid pool to supplement the consumption during film formation. Then, the lean liquid is used to circulate and wash the "solid adsorbent" to re-form the film and continue to adsorb CO 2 。

[0046] Until the CO 2 adsorption capacity in the solution in the rich liquid pool reaches 1.5 mol / kg, the solution in the rich liquid pool is collected into the regeneration device, desorbed and regenerated at 100 °C. Subsequently, by adding clear water to the regenerated lean liquid, the absorbent concentration in the regenerated liquid is restored to 20 wt%, and it flows back into the lean liquid pool to continue the next round of adsorption.

[0047] The porous solid materials used in this example, including activated carbon fibers, activated carbon particles, etc., all have a relatively high specific surface area and good mesoporous structure. The specific surface area of the activated carbon fibers used is 1509 m 2 / g, and the pore size distribution is concentrated in the range of 1 - 3 nm (see Figure 3 ), the specific surface area of the activated carbon particles is 1611 m 2 / g, and the pore size distribution is concentrated in the range of 2 - 3 nm (see Figure 4 ).

[0048] In the example of the present invention, the concentration of CO 2 in the air is about 400 ppm.

[0049] <Example 1>

[0050] First, cut a 4 g (3 cm * 6 cm) activated carbon fiber sheet (specific surface area > 1500 m 2 / g), and cut a stainless steel mesh sheet of corresponding size to fix the fiber on the capture device. Prepare three aqueous solutions of triethylenetetramine (TETA) with different concentrations (the mass ratios of TETA to water are 1:0.1, 1:4, and 1:5 respectively). Take 4 g, 36 g, and 40 g of the three solutions respectively, and then pour the above mixtures onto the activated carbon fibers for leaching. Subsequently, adsorb at different wind speeds for 2 h at 293 K. The wind speed is controlled by an external fan, and 0 m / s, 2 m / s, 4 m / s, and 8 m / s are selected. After the adsorption is completed, titrate with 10 mol / L hydrochloric acid. After the reaction is complete, collect the generated CO 2 gas to calculate the CO 2 adsorption capacity, and convert it to CO 2 (mol) / TETA(kg). The specific data are shown in the following table.

[0051] Table 1. Adsorption capacity table of different TETA concentrations and TETA aqueous solution masses at a wind speed of 0 m / s

[0052]

[0053] Table 2. Table of mass adsorption of different TETA concentrations and TETA aqueous solutions at a wind speed of 2.2 m / s

[0054]

[0055] Table 3. Table of mass adsorption of different TETA concentrations and TETA aqueous solutions at a wind speed of 3.4 m / s

[0056]

[0057] Table 4. Table of mass adsorption of different TETA concentrations and TETA aqueous solutions at a wind speed of 4.8 m / s

[0058]

[0059] Combining the results of Tables 1 - 4, when the amount of the TETA aqueous solution is 4 g, the activated carbon fiber sheet carrier is in excess. The solution can obtain a great spread on the carrier surface, so the adsorption efficiency is the highest, the adsorption amount per unit solution within the same time is the largest, but the adsorption amount per unit carrier is very small. When the solution is 36 g, it has a good spreading effect on the carrier surface and can make full use of the high specific surface area of the carrier. Therefore, the adsorption amount per unit solution is slightly less than that of 4 g, but the adsorption amount per unit carrier is the highest. When the solution reaches 40 g, the solution is in excess, that is, about 4 g of the solution cannot be loaded on the carrier surface for adsorption. Therefore, the total adsorption amount is close to that of 36 g. However, since the amount of the solution used in the calculation is still 40 g, the adsorption amount per unit solution is slightly less than that of 36 g.

[0060] In the case of 4 g of the carrier in the example, taking 36 g of the solution is the optimal liquid loading amount, and 40 g of the solution is in excess. Part of the solution will drip during the adsorption process. Therefore, the conclusion is to select 36 g of the solution loading amount as the optimal loading amount.

[0061] <Example 2>

[0062] First, cut a 4 - g (3 cm * 6 cm) activated carbon fiber sheet, and cut a stainless - steel mesh sheet of corresponding size to fix the fiber on the trapping device. Prepare three aqueous solutions of tetraethylenepentamine (TEPA) with different concentrations (the mass ratios of TEPA to water are 1:0.1, 1:4, and 1:5 respectively). Take 4 g, 36 g, and 40 g of the three solutions respectively, and then pour the above - mentioned mixed solutions onto the activated carbon fibers respectively. Then, adsorb at different wind speeds for 2 h at 293 K. The wind speed is controlled by an external fan, and 0 m / s, 2 m / s, 4 m / s, and 8 m / s are selected. After the adsorption is completed, titrate with 10 mol / L hydrochloric acid. After the reaction is complete, collect the generated CO 2 gas to calculate the CO 2 adsorption amount, and convert it to CO2 (mol) / TEPA(kg), and the specific data are shown in the following table.

[0063] Table of mass adsorption amounts of different TEPA concentrations and TEPA aqueous solutions at a wind speed of 5.0 m / s

[0064]

[0065] Table of mass adsorption amounts of different TEPA concentrations and TEPA aqueous solutions at a wind speed of 6.2 m / s

[0066]

[0067] Table of mass adsorption amounts of different TEPA concentrations and TEPA aqueous solutions at a wind speed of 7.4 m / s

[0068]

[0069] Table of mass adsorption amounts of different TEPA concentrations and TEPA aqueous solutions at a wind speed of 8.8 m / s

[0070]

[0071] <Example 3>

[0072] First, cut a 4 g (3 cm * 6 cm) activated carbon fiber sheet, and cut a stainless steel mesh sheet of corresponding size to fix the fiber on the trapping device. Prepare three aqueous solutions of polyethyleneimine (PEI, M.W. 800) with different concentrations (the mass ratios of PEI to water are 1:0.1, 1:4, and 1:5 respectively). Take 4 g, 36 g, and 40 g of the three solutions respectively, and then rinse the above mixtures on the activated carbon fibers respectively. Then adsorb at different wind speeds for 2 h at 293 K. The wind speed is controlled by an external fan, and 0 m / s, 2 m / s, 4 m / s, and 8 m / s are selected. After the adsorption is completed, titrate with 10 mol / L hydrochloric acid. After the reaction is complete, collect the generated CO 2 gas and calculate the CO 2 adsorption amount, and convert it to CO 2 (mol) / PEI(kg), and the specific data are shown in the following table.

[0073] Table of mass adsorption amounts of different PEI concentrations and PEI aqueous solutions at a wind speed of 9.0 m / s

[0074]

[0075] Table of mass adsorption amounts of different PEI concentrations and PEI aqueous solutions at a wind speed of 10.2 m / s

[0076]

[0077] Table 11. Table of mass adsorption of different PEI concentrations and PEI aqueous solutions at a wind speed of 1.4 m / s

[0078]

[0079] Table 12. Table of mass adsorption of different PEI concentrations and PEI aqueous solutions at a wind speed of 1.8 m / s

[0080]

[0081] <Example 4>

[0082] First, imidazole (IM) and DBN (molar ratio IM:DBN = 2:1) were mixed and stirred at 80 °C for 2 h to obtain the required ionic liquid. Subsequently, 4 g (3 cm * 6 cm) of activated carbon fiber sheets were cut, and stainless steel mesh sheets of corresponding size were cut to fix the fibers on the trapping device. Three ionic liquid ([DBN][IM] 2 ) aqueous solutions ([DBN][IM] 2 with mass ratios to water of = 1:0.1, 1:4, 1:5) were prepared respectively. 4 g, 36 g, and 40 g of the three solutions were taken respectively, and then the above mixtures were respectively rinsed onto the activated carbon fibers. Subsequently, adsorption was carried out at different wind speeds for 2 h at 293 K, and the wind speed was controlled by an external blower, and 0 m / s, 2 m / s, 4 m / s, and 8 m / s were selected. After adsorption, titration was carried out with 10 mol / L hydrochloric acid. After the reaction was complete, the generated CO 2 gas was collected to calculate the CO 2 adsorption amount, and it was converted to CO 2 (mol) / [DBN][IM] 2 (kg). The specific data are shown in the following table.

[0083] Table 13. Table of mass adsorption of different [DBN][IM] 2 concentrations and [DBN][IM] 2 aqueous solution at a wind speed of 0 m / s

[0084]

[0085] Table 14. Table of mass adsorption of different [DBN][IM] 2 concentrations and [DBN][IM] 2 aqueous solution at a wind speed of 2 m / s

[0086]

[0087] Table 15. Table of mass adsorption of different [DBN][IM]2 concentrations and [DBN][IM]2 aqueous solutions at a wind speed of 4 m / s

[0088]

[0089] Table of the mass adsorption amount of different [DBN][IM]2 concentrations and [DBN][IM]2 aqueous solutions at a wind speed of 168 m / s

[0090]

[0091] <Example 5>

[0092] First, IM and TEPA (molar ratio IM:TEPA = 2:1) were mixed and stirred at 80 °C for 2 h to obtain the required ionic liquid. Subsequently, 4 g (3 cm * 6 cm) of activated carbon fiber sheets were cut, and stainless steel mesh sheets of corresponding sizes were cut to fix the fibers on the trapping device. Three different concentrations of the above ionic liquid ([TEPA][IM] 2 ) aqueous solutions ([TEPA][IM] 2 with mass ratios to water of = 1:0.1, 1:4, 1:5) were prepared. 4 g, 36 g, and 40 g of the three solutions were taken respectively, and then the above mixtures were separately rinsed onto the activated carbon fibers. Subsequently, adsorption was carried out at different wind speeds for 2 h at 293 K. The wind speed was controlled by an external fan, and 0 m / s, 2 m / s, 4 m / s, and 8 m / s were selected. After adsorption, titration was carried out with 10 mol / L hydrochloric acid. After the reaction was complete, the generated CO 2 gas was collected to calculate the CO 2 adsorption amount, and it was converted to CO 2 (mol) / [TEPA][IM] 2 (kg). The specific data are shown in the following table.

[0093] Table of the mass adsorption amount of different [TEPA][IM] 2 concentrations and [TEPA][IM] 2 aqueous solutions at a wind speed of 17.0 m / s

[0094]

[0095]

[0096] Table of the mass adsorption amount of different [TEPA][IM] 2 concentrations and [TEPA][IM] 2 aqueous solutions at a wind speed of 18.2 m / s

[0097]

[0098] Table of the mass adsorption amount of different [TEPA][IM]2 concentrations and [TEPA][IM]2 aqueous solutions at a wind speed of 19.4 m / s

[0099]

[0100] Table of mass adsorption amounts of different [TEPA][IM]2 concentrations and [TEPA][IM]2 aqueous solutions at a wind speed of 20.8 m / s

[0101]

[0102]

[0103] <Example 6>

[0104] First, pyridine (Py) and DBN (molar ratio Py:DBN = 2:1) were mixed and stirred at 80 °C for 2 h to obtain the required ionic liquid. Subsequently, 4 g (3 cm * 6 cm) of activated carbon fiber sheets were cut, and stainless steel mesh sheets of corresponding sizes were cut to fix the fibers on the trapping device. Three different concentrations of the above ionic liquid ([DBN][Py] 2 ) aqueous solutions ([DBN][Py] 2 with mass ratios to water of = 1:0.1, 1:4, 1:5) were prepared. 4 g, 36 g, and 40 g of the three solutions were taken respectively, and then the above mixtures were separately rinsed onto the activated carbon fibers. Subsequently, adsorption was carried out at different wind speeds for 2 h at 293 K. The wind speed was controlled by an external blower, and 0 m / s, 2 m / s, 4 m / s, and 8 m / s were selected. After adsorption, titration was carried out with 10 mol / L hydrochloric acid. After the reaction was complete, the generated CO 2 gas was collected to calculate the CO 2 adsorption amount, and it was converted to CO 2 (mol) / [DBN][Py] 2 (kg). The specific data are shown in the following table.

[0105] Table of mass adsorption amounts of different [DBN][Py] 2 concentrations and [DBN][Py] 2 aqueous solutions at a wind speed of 21.0 m / s

[0106]

[0107] Table of mass adsorption amounts of different [DBN][Py] 2 concentrations and [DBN][Py] 2 aqueous solutions at a wind speed of 22.2 m / s

[0108]

[0109]

[0110] Table of the mass adsorption of different concentrations of [DBN][Py]2 and [DBN][Py]2 aqueous solution at a wind speed of 23.4 m / s

[0111]

[0112] Table of the mass adsorption of different concentrations of [DBN][Py]2 and [DBN][Py]2 aqueous solution at a wind speed of 24.8 m / s

[0113]

[0114] <Example 7>

[0115] First, Py and TEPA (molar ratio Py:TEPA = 2:1) were mixed and stirred at 80 °C for 2 h to obtain the required ionic liquid. Subsequently, 4 g (3 cm * 6 cm) of activated carbon fiber sheets were cut, and stainless steel mesh sheets of corresponding sizes were cut to fix the fibers on the trapping device. Three aqueous solutions of the above ionic liquid ([TEPA][Py] 2 ) with different concentrations ([TEPA][Py] 2 and water mass ratios of 1:0.1, 1:4, 1:5 respectively) were prepared. 4 g, 36 g, and 40 g of the three solutions were taken respectively, and then the above mixtures were respectively rinsed onto the activated carbon fibers. Subsequently, adsorption was carried out at different wind speeds for 2 h at 293 K. The wind speed was controlled by an external fan, and 0 m / s, 2 m / s, 4 m / s, and 8 m / s were selected. After adsorption, titration was carried out with 10 mol / L hydrochloric acid. After the reaction was complete, the generated CO 2 gas was collected to calculate the CO 2 adsorption amount, and it was converted to CO 2 (mol) / [TEPA][Py] 2 (kg). The specific data are shown in the following table.

[0116] Table of the mass adsorption of different concentrations of [TEPA][Py] 2 and [TEPA][Py] 2 aqueous solution at a wind speed of 25.0 m / s

[0117]

[0118] Table of the mass adsorption of different concentrations of [TEPA][Py] 2 and [TEPA][Py] 2 aqueous solution at a wind speed of 26.2 m / s

[0119]

[0120] Table of different [TEPA][Py]2 concentrations and mass adsorption amounts of [TEPA][Py]2 aqueous solutions at a wind speed of 27.4 m / s

[0121]

[0122]

[0123] Table of different [TEPA][Py]2 concentrations and mass adsorption amounts of [TEPA][Py]2 aqueous solutions at a wind speed of 28.8 m / s

[0124]

[0125] <Example 8>

[0126] First, weigh 4 g of activated carbon particles (specific surface area > 1600 m 2 / g), and cut stainless steel mesh sheets of appropriate size to fix the activated carbon particles on the trapping device. Prepare three aqueous solutions of tetraethylenepentamine (TEPA) with different concentrations (the mass ratios of TEPA to water are 1:0.1, 1:4, and 1:5 respectively). Take 4 g, 36 g, and 40 g of the three solutions respectively, and then pour the above mixtures onto the activated carbon fibers respectively. Then adsorb at different wind speeds for 2 h at 293 K. The wind speed is controlled by an external fan, and 0 m / s, 2 m / s, 4 m / s, and 8 m / s are selected. After adsorption, titrate with 10 mol / L hydrochloric acid. After the reaction is complete, collect the generated CO 2 gas to calculate the CO 2 adsorption amount, and convert it to CO 2 (mol) / TEPA(kg). The specific data are shown in the following table.

[0127] Table of different TEPA concentrations and mass adsorption amounts of TEPA aqueous solutions at a wind speed of 29.0 m / s

[0128]

[0129]

[0130] Table of different TEPA concentrations and mass adsorption amounts of TEPA aqueous solutions at a wind speed of 30.2 m / s

[0131]

[0132] Table of different TEPA concentrations and mass adsorption amounts of TEPA aqueous solutions at a wind speed of 31.4 m / s

[0133]

[0134] Table of the mass adsorption of different TEPA concentrations and TEPA aqueous solutions at a wind speed of 32.8 m / s

[0135]

[0136]

[0137] <Example 9>

[0138] Use the TEPA aqueous solution in the above Example 2 for subsequent air capture. The TEPA concentration is set at 20 wt% (mass ratio of TEPA to water = 1:4). Cut a 4 g (3 cm * 6 cm) activated carbon fiber sheet, and cut a stainless steel mesh sheet of corresponding size to fix the fiber on the capture device. Take 36 g of the above mixture and wash it on the activated carbon fiber. Subsequently, under the condition of 293 K, blow it with a wind speed of 2 m / s for 2 h. After adsorption, wash it with the first batch of 20 g of clear water and collect it, which is recorded as the first batch of rich liquid. Then wash it with the second batch of 20 g of clear water and collect it, which is recorded as the second batch of rich liquid. And so on, perform multiple batches of 20 g of clear water washing to obtain multiple batches of enriched CO 2 rich liquid.

[0139] Titrate the rich liquid of each batch of washing liquid with 10 mol / L hydrochloric acid, and use the acid-base titration method to calculate the CO 2 adsorption amount contained in the rich liquid of each batch respectively, and convert it to CO 2 (mol) / mass of rich liquid (kg). The specific data is shown in the following table.

[0140] Table 33. CO 2 adsorption amount in each batch of rich liquid.

[0141]

[0142]

[0143] As can be seen from Table 33, after 6 batches of 20 g of clear water washing, the content of CO 2 enriched in the subsequent batches of washing rich liquid is low. It can be foreseen that 6 batches of 20 g of clear water washing can reduce the CO 2 concentration in the residual rich liquid on the surface of the activated carbon fiber as much as possible.

[0144] <Example 10>

[0145] Use the TEPA aqueous solution in the above Example 2 for subsequent air capture. The TEPA concentration is set at 20 wt%

[0146] (TEPA to water mass ratio = 1:4), cut a 4 g (3 cm * 6 cm) activated carbon fiber sheet, and cut a stainless steel mesh sheet of corresponding size to fix the fiber on the trapping device. Take 36 g of the above-mentioned mixed solution and wash it on the activated carbon fiber. Subsequently, under the condition of 293 K, blow it with a wind speed of 2 m / s for 2 h. After adsorption, wash it with 120 g of clear water. Subsequently, according to the method of Example 9, use multiple batches of 20 g of lean liquid for washing and collection. Titrate each batch of washing liquid with 10 mol / L hydrochloric acid, and use the acid-base titration method to calculate the CO 2 adsorption capacity, and convert it to CO 2 (mol) / lean liquid mass (kg). The specific data is shown in the following table.

[0147] Table 34. CO in each batch of lean liquid 2 adsorption capacity.

[0148]

[0149]

[0150] As can be seen from Table 34, after washing with 160 g of lean liquid, the content of CO enriched in the subsequent batches of washing lean liquid is low. It can be predicted that washing with 160 g of lean liquid can reduce the CO 2 concentration in the residual rich liquid on the surface of the activated carbon fiber as much as possible. 2 concentration as much as possible.

[0151] <Example 11>

[0152] Use the TEPA aqueous solution in Example 2 above for subsequent air trapping. The TEPA concentration is set at 20 wt% (TEPA to water mass ratio = 1:4). Cut a 4 g (3 cm * 6 cm) activated carbon fiber sheet, and cut a stainless steel mesh sheet of corresponding size to fix the fiber on the trapping device. Take 36 g of the above-mentioned mixed solution and wash it on the activated carbon fiber. Subsequently, under the condition of 293 K, blow it with a wind speed of 2 m / s for 2 h. After adsorption, wash it with 120 g of clear water. Record it as rich liquid ① after collection. Subsequently, wash it again with 160 g of lean liquid, blow it with 2 m / s air under the condition of 293 K for 2 h. After adsorption, wash and enrich it with rich liquid ①, and record it as rich liquid ② after collection. Repeat the above steps, titrate each batch of washing liquid with 10 mol / L hydrochloric acid, collect the generated CO 2 gas to calculate the CO 2 adsorption capacity, and use the acid-base titration method to calculate the CO 2 adsorption capacity contained in each batch of rich liquid respectively, and convert it to CO 2 (mol) / rich liquid mass (kg). Until the adsorption capacity reaches 1.5 mol CO 2 / kg rich liquid.

[0153] Table 35. CO in the rich liquid per cycle 2 Adsorption capacity.

[0154] Washing cycles <![CDATA[Rich liquid CO 2 Capture amount (mol / kg)]]> Rich liquid ① 0.22 Rich liquid ② 0.42 Rich liquid ③ 0.61 Rich liquid ④ 0.8 Rich liquid ⑤ 0.98 Rich liquid ⑥ 1.16 Rich liquid ⑦ 1.34 Rich liquid ⑧ 1.52

[0155] <Example 12>

[0156] Use the TEPA aqueous solution in Example 2 above for subsequent air capture. The TEPA concentration is set at 20 wt% (mass ratio of TEPA to water = 1:4). Cut 4 g (3 cm * 6 cm) of activated carbon fiber sheets, and cut stainless steel mesh sheets of corresponding size to fix the fibers on the capture device. Take 36 g of the above mixture and wash it on the activated carbon fibers. Subsequently, under the condition of 293 K, blow with a wind speed of 2 m / s for 2 h. After adsorption, wash with 120 g of clear water. Record it as rich liquid ① after collection. Then wash again with 160 g of lean liquid, blow with air at 2 m / s for 2 h under the condition of 293 K. After adsorption, wash and enrich with rich liquid ①, and record it as rich liquid ② after collection. Repeat the above steps until the adsorption capacity reaches 1.5 mol CO 2 / kg of rich liquid, and then perform desorption at different temperatures. When the desorption temperature exceeds 100 °C, it is necessary to condense the mixed gas to remove water vapor to obtain pure CO 2 , by collecting the generated CO 2 Volume conversion of CO 2 Desorption amount, and convert it to CO 2 (mol) / mass of rich liquid (kg).

[0157] Table 36. CO desorption amount at different temperatures 2 Desorption amount.

[0158] Analysis temperature (℃) Analysis quantity (mol / kg) Analysis rate 80 0.91 60％ 90 1.21 80％ 100 1.44 95％ 110 1.46 96％ 120 1.49 98％ 130 1.5 99％ 140 1.5 99％

[0159] In summary, the CO capture method provided by this patent still has a good adsorption effect at a relatively low wind speed outdoors, and can improve the final rich liquid concentration for desorption through cyclic washing, with good economic benefits. 2 The content described in this specification is only a list of the implementation forms of the inventive concept, and the protection scope of the present invention should not be regarded as limited to the specific forms stated in the embodiments.

[0160] The content described in this specification is only a list of the implementation forms of the inventive concept, and the protection scope of the present invention should not be regarded as limited to the specific forms stated in the embodiments.

Claims

1. A method for capturing carbon dioxide in the air with low energy consumption by solid phase liquid membrane method, characterized in that The following steps are involved: 1) Solid-phase liquid film formation stage: a high-boiling-point CO2 liquid absorbent is mixed with water to prepare an absorption liquid, which is recorded as a lean liquid; the lean liquid is first impregnated on a porous solid material with a high specific surface area to form a liquid film layer, and the mass ratio of the porous solid material to the lean liquid is 1:1-10, to obtain a solid-phase adsorbent loaded with a liquid film; 2) Rapid adsorption stage: The solid phase adsorbent loaded with liquid film is fully exposed to the air and in contact with the flowing air. The low concentration CO2 in the air is quickly transferred to the surface of the liquid film through the concentration difference to achieve concentrated adsorption until the liquid film on the surface of the solid phase adsorbent is saturated with CO2 adsorption; 3) Liquid film washing and collection stage: Through the clean water circulation washing, the liquid film is detached from the surface of the solid phase adsorbent to obtain the regeneration liquid rich in CO2, which is recorded as rich liquid; 4) Re-filming, adsorption, liquid film washing and collection stage: Repeat steps 1)-3), use lean solution to circulate and wash the solid phase adsorbent to make the film form again, and then carry out the next round of adsorption. After the CO2 adsorption is saturated, rich solution is still used for circulatory washing until the CO2 adsorption amount in the rich solution reaches the concentration required for regeneration, and then it is collected for subsequent regeneration; 5) Rich liquid regeneration stage: The collected rich liquid enters the analytical tower for heating and desorption regeneration to obtain high-purity CO2 gas for storage and subsequent utilization. After the rich liquid is regenerated, it is reused in the liquid membrane washing and collection stage, or after the rich liquid is regenerated, clean water is added to balance the concentration to form a lean liquid, which is used to re-enter the membrane formation stage; The porous solid phase material is at least one of activated carbon particles, activated carbon fibers, and macroporous resins, and has a specific surface area of ​​500 m 2 / g or more, the mass ratio of the high boiling point CO2 liquid phase absorbent to water in step 1) is 1:0.1~5; The method is operated by using the following devices, including a CO2 adsorption device, a rich liquid circulation pump, a rich liquid tank, a lean liquid circulation pump, a lean liquid tank and a desorption tower, wherein the CO2 adsorption device is used to fix and load the porous solid phase material; In the dipping biofilm formation stage, the lean liquid circulation pump is used to transport the lean liquid in the lean liquid pool to the CO2 adsorption device for dripping biofilm formation on the porous solid phase material, and the dripping lean liquid is collected in the lean liquid pool to form a cycle until the lean liquid forms a biofilm on the porous solid phase material; In the first liquid film washing and collection stage, clean water is first added to the rich liquid pool, and the rich liquid circulation pump is used to transport the rich liquid in the rich liquid pool to the CO2 adsorption device for drip washing of the porous solid phase material, and the dripping rich liquid dripping liquid is collected in the rich liquid pool to form a cycle until the liquid film is eluted from the surface of the porous solid phase material; in the subsequent liquid film washing and collection stage, the rich liquid in the rich liquid pool is still used for circulating elution until the CO2 adsorption amount in the rich liquid reaches the concentration required for regeneration, and is collected for subsequent regeneration; During the rich liquid regeneration stage, the collected rich liquid enters the analysis tower for heating and desorption regeneration. Part of the water evaporates and escapes with the CO2 gas. The escaped mixed steam is condensed to condense the water in it, and high-purity CO2 gas can be obtained for storage and subsequent utilization.

2. A method for capturing carbon dioxide in the air using a solid phase liquid membrane method with low energy consumption as claimed in claim 1, characterized in that In step 1), the high boiling point CO2 liquid phase absorbent is at least one of an organic amine and an ionic liquid, the organic amine is at least one of triethylenetetramine, tetraethylenepentamine, and polyethyleneimine, the ionic liquid includes a cation donor and an anion donor, the cation donor is imidazole or pyridine, and the anion donor is 1,5-diazabicyclo[4.3.0]non-5-eneDBN or tetraethylenepentamine; the preparation method of the ionic liquid is: mixing the cation donor and the anion donor in a molar ratio of 1.5-3:1, and stirring at 70-80°C for 1-3 hours.

3. A method for capturing carbon dioxide in air using a solid phase liquid membrane method with low energy consumption as claimed in claim 1, characterized in that The specific surface area of ​​the porous solid phase material is 1000m 2 / g or more; in step 1), the mass ratio of the high boiling point CO2 liquid absorbent to water is 1:4~5, and the mass ratio of the porous solid phase material to the lean liquid is 1:9~10.

4. A method for capturing carbon dioxide in air using a solid phase liquid membrane method with low energy consumption as claimed in claim 1, characterized in that The adsorption time in step 2) is 1-10 h.

5. A method for capturing carbon dioxide in air using a solid phase liquid membrane method with low energy consumption as claimed in claim 4, characterized in that The adsorption time in step 2) is 2-4h.

6. A method for capturing carbon dioxide in air using a solid phase liquid membrane method with low energy consumption as claimed in claim 1, characterized in that The mass ratio of the clean water used for washing the liquid membrane in step 3) or the rich liquid used for washing the liquid membrane in step 4) to the porous solid phase material is 20-50:

1.

7. A method for capturing carbon dioxide in air using a solid phase liquid membrane method with low energy consumption as claimed in claim 6, characterized in that The mass ratio of the clean water used for washing the liquid membrane in step 3) or the rich liquid used for washing the liquid membrane in step 4) to the porous solid phase material is 30:

1.

8. The method for capturing carbon dioxide in air by a solid phase liquid membrane method with low energy consumption as claimed in claim 1, characterized in that In step 4), the mass ratio of the lean solution used for circulating elution for re-film formation to the porous solid phase material is 20-50:1; in step 4), the regeneration required concentration of CO2 adsorption in the rich solution is above 1.0 mol / kg.

9. A method for capturing carbon dioxide in air using a solid phase liquid membrane method with low energy consumption as claimed in claim 8, characterized in that In step 4), the mass ratio of the lean solution used for circulating elution to form the membrane again to the porous solid phase material is 40:1; in step 4), the regeneration required concentration of CO2 adsorption in the rich solution is above 1.5 mol / kg.

10. The method for capturing carbon dioxide in air by a solid phase liquid membrane method with low energy consumption as claimed in claim 1, characterized in that The rich solution regeneration temperature in step 5) is 80-130°C.

11. A method for capturing carbon dioxide in air using a solid phase liquid membrane method with low energy consumption as claimed in claim 10, characterized in that The rich solution regeneration temperature in step 5) is 90-100°C.

12. A method for capturing carbon dioxide in air using a solid phase liquid membrane method with low energy consumption as claimed in claim 1, characterized in that The concentration of low-concentration CO2 in the air is below 400ppm.

13. A method for capturing carbon dioxide in air using a solid phase liquid membrane method with low energy consumption as claimed in claim 12, characterized in that The concentration of low concentration CO2 in the air is 300-400ppm 14. A method for capturing carbon dioxide in air using a solid phase liquid membrane method with low energy consumption as claimed in claim 1, characterized in that The CO2 adsorption device comprises a supporting main pipe (1), a main infusion pipe arranged inside the main infusion pipe, and a plurality of branch pipes (3) arranged at even intervals along the circumference of the upper end side of the main infusion pipe, wherein the outlet of the main infusion pipe is connected to each branch pipe (3); A stainless steel mesh frame (5) is fixedly arranged below each shunt pipe (3). A plurality of drip holes (4) are evenly arranged at the bottom of the shunt pipe (3) near the stainless steel mesh frame (5) along the length direction thereof. Two stainless steel mesh sheets and a porous solid phase material sandwiched between them are installed on the stainless steel mesh frame (5). A reflux groove (6) is arranged below the stainless steel mesh frame (5). The reflux groove (6) is fixed on the supporting main pipe (1). A liquid collecting groove (7) is also arranged on the side of the lower end of the supporting main pipe (1). Each reflux groove (6) is inclined toward the liquid collecting groove (7) and is connected to the liquid collecting groove (7) through a liquid outlet pipeline. A tank liquid outlet (8) is arranged at the bottom of the liquid collecting groove (7). The tank liquid outlet (8) is divided into two paths, which are respectively connected to a rich liquid pool and a lean liquid pool by pipelines. The inlet of the liquid infusion main pipe is divided into two paths, one of which is connected to the rich liquid pool by pipelines through a rich liquid circulation pump, and the other of which is connected to the lean liquid pool by pipelines through a lean liquid circulation pump. Control valves are arranged on the corresponding pipelines.

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