Carbon dioxide capture agent, and capture, storage and utilization method for carbon dioxide

Abstract

Provided are a carbon dioxide capture agent, and a capture, storage and utilization method for carbon dioxide. The carbon dioxide capture agent composition comprises a carboxylic acid, a solvent and an alkali, the solvent being a good solvent for carboxylic acids and alkalis, and the chemical formula of the carboxylic acid being R-COOH, wherein R is a substituted or unsubstituted C4-C21 hydrocarbon group, the substitution refers to one or more H on an alkyl group being substituted by a hydrocarbon group, -OH, -COOH, an aryl group, an amino group, or -X, and X refers to halogen atoms F, Cl, Br or I. Using the carboxylic acid and alkali as raw materials, a carboxylate aqueous solution is prepared as a CO2 absorbent, and the prepared CO2 absorbent has excellent CO2 capture performance. After being captured by the CO2 absorbent, the CO2 exhibits a stable property and can be stored easily. In addition, the CO2 absorbent does not need or only needs to consume a small amount of external energy for reversibly releasing the CO2 for regeneration, thereby achieving the cyclic utilization of the absorbent.

Description

Carbon dioxide capture agent and carbon dioxide capture, storage and utilization method

[0001] This application claims priority from the following prior application: Patent Application No. 2023115391844, filed with the State Intellectual Property Office of China on November 17, 2023, entitled “A Carbon Dioxide Capture Agent and Method for Capturing, Storing, and Utilizing Carbon Dioxide.” The entire text of that prior application is incorporated herein by reference. Technical Field

[0002] The present invention belongs to the field of carbon dioxide capture, and in particular relates to a carbon dioxide capture agent and a method for capturing, storing and utilizing carbon dioxide, for example, a carbon dioxide capture agent in flue gas and a method for capturing, storing and utilizing carbon dioxide. Background Art

[0003] The combustion of fossil fuels produces large amounts of CO2. The environmental pollution and climate change caused by these massive emissions have become one of the major threats facing human society. To address global warming and other climate change issues, countries around the world have proposed carbon neutrality initiatives. In 2015, the 21st Conference of the Parties to the United Nations Framework Convention on Climate Change (COP21) set a goal of achieving zero emissions by 2050. China has also proposed a "dual carbon target," which calls for a significant reduction in energy-related CO2 emissions. Of the six greenhouse gases, carbon dioxide emissions contribute approximately 75%, making them the most impactful.

[0004] Generally speaking, there are four main pathways to achieving a significant reduction in carbon dioxide emissions: energy conservation and improved energy efficiency; replacing fossil energy with non-fossil fuels; leveraging new technologies to capture, store, and utilize carbon dioxide; and increasing carbon sinks through afforestation. The first three are related to the energy system. While afforestation is relatively low-cost, it requires a lot of land, which will compete with the agricultural sector's goal of increasing productivity.

[0005] Compared to other technologies, carbon capture, storage, and utilization (CCS) is the only negative emissions technology capable of reducing atmospheric CO2 levels. This technology primarily consists of three components: capture, storage, and utilization. Capture is the first step in CCS. Carbon dioxide must be present at a high purity for transportation, storage, and utilization. In most cases, the concentration of CO2 in industrial exhaust gases is low, so it must be separated from the exhaust gases. This process is called CO2 capture. The International Energy Agency's "Carbon Dioxide Emissions 2022" report indicates that the largest absolute increase in global CO2 emissions by sector from 2019 to 2022 was in power generation and heating. Therefore, the power industry is a prime candidate for CCS (Carbon Capture and Storage) technology. Capturing CO2 from flue gas requires technological retrofitting of CO2 emission sources and installing CO2 capture systems. Generally speaking, depending on the different locations of carbon dioxide capture during the life cycle of fossil energy, the capture technologies applicable to power plants are divided into three types: "post-combustion capture", "pre-combustion capture" and "oxygen-enriched combustion". Among them, the "post-combustion capture" technology is applicable to the modification of existing power plant flues and is therefore the most widely used. The main methods for capturing carbon dioxide from flue gas in power plant flues include chemical absorption using alkaline solutions and physical absorption using non-corrosive solvents such as methanol or polyethylene glycol dimethyl ether. They also include adsorption using porous solid adsorbents and membrane separation methods. However, adsorption and membrane separation methods have not yet been widely used due to their low CO2 separation efficiency. Among these major capture technologies, chemical absorption and physical absorption are relatively mature and have been widely used in the chemical industry.

[0006] Amine scrubbing is a method for removing acid gases. Since R.R. Bottoms patented the use of ethanolamine solutions for acid gas removal in 1930, alkylolamine decarbonization has become a widely used method for gas purification. However, this method has the following drawbacks: a) When used in systems containing large amounts of nitrogen oxides and / or sulfur-containing gases, they must be purified beforehand; and b) liquid amines have several significant drawbacks, including amine evaporation, corrosion to equipment, and high regeneration energy costs. A feasible approach to reducing corrosiveness and regeneration energy is the use of supported amine adsorbents. However, the high cost of synthesizing these supported amine adsorbents currently precludes large-scale industrial application.

[0007] Radu Custelcean's team reported a method for direct air capture at a laboratory scale using most readily available materials and equipment: using a household humidifier, CO2 absorption is achieved through an aqueous solution of readily available and environmentally friendly amino acids (glycine and sarcosine), and then the CO2-absorbed solution is reacted with a simple guanidine compound (guanidine adsorbent) to obtain guanidine compound crystals, which crystallize into insoluble carbonates. Finally, by using concentrated solar energy to relatively gently heat the carbonate crystals, nearly quantitative regeneration of the guanidine compound and effective CO2 release can be achieved. However, the regeneration temperature of the guanidine adsorbent is relatively high (80-120°C), which requires more energy consumption.

[0008] On the other hand, CCS faces technical immaturity, high costs, energy consumption, and risks in CO2 transportation and storage. Therefore, developing a CO2 capture agent with excellent capture performance, low regeneration energy consumption, and environmental friendliness is key to carbon dioxide capture, storage, and utilization. Summary of the Invention

[0009] In order to improve the deficiencies of the prior art, the present invention provides a carbon dioxide capture agent and a method for capturing, storing and utilizing carbon dioxide. Specifically, it provides a carbon dioxide capture agent in flue gas and a method for capturing, storing and utilizing carbon dioxide. The carbon dioxide capture agent is a carboxylate aqueous solution prepared with carboxylic acid and alkali as raw materials. The capture agent captures CO2 by being protonated in response to the pH change caused by CO2 bubbling and dissolving in the solution. Therefore, it can be used as a CO2 absorbent. The CO2 absorbent has excellent CO2 capture performance.

[0010] A carbon dioxide capture agent composition, comprising a carboxylic acid, a solvent and a base, wherein the solvent is a good solvent for the carboxylic acid and the base, and the chemical formula of the carboxylic acid is R-COOH, wherein R is a substituted or unsubstituted C4~C 21 Hydrocarbon group.

[0011] According to an embodiment of the present invention, the substitution refers to that one or more H on the alkyl group is replaced by a hydrocarbon group, -OH, -COOH, an aryl group, an amino group or -X, wherein X refers to a halogen atom F, Cl, Br or I.

[0012] According to an embodiment of the present invention, the R contains one or more alkene groups and / or alkyne groups.

[0013] According to an embodiment of the present invention, the carboxylic acid is C8~C 18 A saturated monocarboxylic acid such as octanoic acid, nonanoic acid, decanoic acid, undecanoic acid or dodecanoic acid.

[0014] According to an embodiment of the present invention, the carboxylic acid is C8~C 14The polycarboxylic acid is, for example, octanedioic acid, undecanedioic acid, dodecanedioic acid or tridecanedioic acid.

[0015] According to an embodiment of the present invention, the carboxylic acid is C8~C 22 The mono- or polyunsaturated carboxylic acid is, for example, 2-octenoic acid, 2-nonenoic acid, 3-nonenoic acid, 10-undecenoic acid, oleic acid, linoleic acid, ricinoleic acid, eicosapentaenoic acid or docosatetraenoic acid.

[0016] According to an embodiment of the present invention, the carboxylic acid is a C5-C 12 The carboxylic acid is, for example, at least one of phenylvaleric acid, phenylnonanoic acid, phenylazelaic acid, phenylnonenoic acid, and phenylnonadienoic acid.

[0017] According to an embodiment of the present invention, the base is selected from at least one of an inorganic base and an organic base.

[0018] According to an embodiment of the present invention, the inorganic base may be at least one of NaOH, KOH, Ca(OH)2, LiOH, NH3H2O, NaHCO3, Na2CO3, KHCO3, K2CO3, Ca(HCO3)2, and CaCO3.

[0019] According to an embodiment of the present invention, the organic base may be at least one of methylamine, ethylamine, propylamine, butylamine, ethylenediamine, ethanolamine, and triethanolamine, for example, ethanolamine.

[0020] According to an embodiment of the present invention, the solvent can be water or a composite solvent; specifically, the composite solvent is a composite solvent of water and an organic solvent, for example, the composite solvent is selected from at least one of water / methanol, water / ethanol, water / propanol, and water / acetonitrile, for example, water / acetonitrile.

[0021] According to an embodiment of the present invention, the molar amounts of the carboxylic acid and the base are equal or the base is in excess, for example, the molar ratio can be 1:1, 1:1.1, 1:1.5, or 1:2.

[0022] According to an embodiment of the present invention, the molar amount of the carboxylic acid and the base is equal or the base is in excess. + With OH in the base - The molar ratio is less than or equal to 1. When the carboxylic acid is excessive, it cannot be completely salted and the absorption effect is poor. When the alkali is excessive, the absorption performance is improved, including the common absorption performance of carboxylate and alkali. After regeneration, the absorption performance is the absorption performance of carboxylate, but the carboxylate absorbed by the alkali cannot be regenerated.

[0023] According to an embodiment of the present invention, the composition further comprises a carboxylate formed by a carboxylic acid and a base. Specifically, in the composition, the mass fraction of the carboxylate formed by the carboxylic acid and the base is greater than 0 and less than or equal to 30%, for example, greater than 3 and less than or equal to 20%, and exemplary is 1%, 2%, 2.5%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 12%, 15%, 18%, 20%, 25%.

[0024] A carbon dioxide capture agent, comprising a solvent and a carboxylate dissolved in the solvent, wherein the mass fraction of the carboxylate is greater than 0 and less than or equal to 30%, for example, greater than 3 and less than or equal to 20%, and exemplary amounts are 1%, 2%, 2.5%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 12%, 15%, 18%, 20%, and 25%.

[0025] According to an embodiment of the present invention, the solvent and the carboxylate salt have the definitions as described above.

[0026] According to an embodiment of the present invention, the pH value of the carbon dioxide capture agent is 7-14, preferably the pH value of the carbon dioxide capture agent is 7-12, for example, 7, 8, 9, 10, 11 or 12.

[0027] According to an embodiment of the present invention, the carbon dioxide capture agent is a micellar solution of a carboxylate. Specifically, after the capture agent captures carbon dioxide, a micellar solution system, an emulsion system, a solid-liquid two-phase system, a liquid-liquid two-phase system, or a solid phase system is formed.

[0028] A method for capturing carbon dioxide, wherein the method uses the above-mentioned carbon dioxide capture agent or the carbon dioxide capture agent composition to capture CO2, comprising the following steps:

[0029] The gas containing CO2 is brought into contact with the above-mentioned composition for carbon dioxide capture agent or the above-mentioned carbon dioxide capture agent to capture CO2.

[0030] According to an embodiment of the present invention, the contacting refers to passing a gas containing CO 2 into the composition for a carbon dioxide capture agent or the carbon dioxide capture agent.

[0031] According to an embodiment of the present invention, the contacting is performed under closed conditions.

[0032] According to an embodiment of the present invention, the contacting comprises first storing the composition for carbon dioxide capture agent or carbon dioxide capture agent in a sealed container, and introducing the CO2-containing gas into the sealed container to contact the composition for carbon dioxide capture agent or carbon dioxide capture agent.

[0033] According to an embodiment of the present invention, a gas inlet channel and a gas outlet channel are provided on the sealed container. The gas inlet channel is used to introduce the gas containing CO2 into the composition for carbon dioxide capture agent or the carbon dioxide capture agent, and the gas outlet channel is used to outlet the gas after CO2 is adsorbed from the sealed container.

[0034] According to an embodiment of the present invention, the CO2-containing gas is in contact with the carbon dioxide capture agent composition or the carbon dioxide capture agent for 0.5 to 4 hours, and preferably the capture contact time is 1 hour, 2 hours or 3 hours.

[0035] According to an embodiment of the present invention, in the gas containing CO2, the partial pressure of the CO2 gas is 2 to 100%, preferably the partial pressure of the CO2 gas is 4 to 100%, and further preferably, the partial pressure of the CO2 gas is 10 to 100%.

[0036] According to an embodiment of the present invention, the gas containing CO 2 is flue gas, and the CO 2 partial pressure in the flue gas is 13% to 20%, so that capture can be achieved.

[0037] According to an embodiment of the present invention, the capture temperature is 0 to 90°C, preferably the capture temperature is 0 to 60°C, and further preferably, the capture temperature is 0 to 50°C, for example, the capture temperature is 5°C, 10°C, 15°C, 20°C, 25°C, 30°C, 35°C or 40°C.

[0038] According to an embodiment of the present invention, the carbon dioxide capture agent composition or the carbon dioxide capture agent has a capture capacity of 5 mg / g to 50 mg / g of CO2 gas.

[0039] According to an embodiment of the present invention, after the CO2 contacts the composition for the carbon dioxide capture agent, the carboxylate forms carboxylic acid and bicarbonate with CO2, thereby forming a micellar solution system, an emulsion system, a solid-liquid two-phase system, a liquid-liquid two-phase system or a solid phase system. These systems have good stability under closed conditions and are easy to transport and store.

[0040] According to an embodiment of the present invention, after capturing CO2, the method further includes the following step: storing the capture agent containing CO2.

[0041] According to an embodiment of the present invention, the storage is to store the capture agent containing CO2 in a closed environment.

[0042] According to an embodiment of the present invention, the temperature of the closed environment is 0-50° C., for example, room temperature.

[0043] According to an embodiment of the present invention, the CO2-containing capture agent is stored in a closed environment for a period of time greater than or equal to 30 days without separation.

[0044] According to an embodiment of the present invention, after capturing CO 2 or storing the capture agent containing CO 2 , the following step is further included: regenerating the capture agent.

[0045] According to an embodiment of the present invention, regenerating the capture agent comprises the following steps: placing the capture agent after capturing CO2 or storing the capture agent containing CO2 in an environment with a CO2 partial pressure of less than 2% to release CO2 and obtain a regenerated capture agent.

[0046] According to an embodiment of the present invention, the releasing of CO2 is performed in an environment with a CO2 partial pressure of less than 1%, preferably in an environment with a CO2 partial pressure of less than 0.5%, such as in the atmosphere.

[0047] According to an embodiment of the present invention, the CO2 is released at a temperature of 0 to 90°C, preferably at a temperature of 20 to 60°C, for example, at normal temperature and pressure.

[0048] According to an embodiment of the present invention, the CO2 absorbed in the capture agent can be reversibly released at room temperature and pressure. The reaction is a reversible reaction. The absorbent can be circulated and regenerated and CO2 can be measured by leaving it in the open at room temperature, introducing inert gas, or providing a temperature above 35°C.

[0049] A composition for a carbon dioxide capture agent, a carbon dioxide capture agent or a carbon dioxide capture method as described above is used in the treatment of CO2 in waste streams in power plants, cement manufacturing, steel manufacturing, glass manufacturing, brewing, synthesis gas production, natural gas and biogas purification, ammonia synthesis or any other industrial process that produces acidic gases, preferably for geological utilization to enhance oil recovery and gas recovery; chemical utilization to prepare liquid fuels and degradable polymers; biological utilization to convert into food, feed, chemicals and bio-CO2 gas fertilizers; or for geological storage, such as for enhancing the mining of oil, natural gas, geothermal energy, shale gas, coalbed methane, and uranium in situ leaching, preparing liquid fuels, synthesizing polyols, methanol, carbonates, degradable polymers, converting them into food and feed, converting them into chemicals, and using them as CO2 gas fertilizers for plants.

[0050] According to the embodiment of the present invention, the storage of CO2 in flue gas is due to the fact that carbon dioxide is an acidic gas. When carbon dioxide is introduced, carbon dioxide reacts with hydroxide produced by the hydrolysis of sodium carboxylate to generate hydrophobic carboxylic acid and NaHCO3; all of them are converted into micellar solution systems, emulsion systems, solid-liquid two-phase systems, liquid-liquid two-phase systems or solid phase systems in the form of transparent carboxylate solutions, and mainly exist in the form of emulsion systems or solid phase systems. They have good stability in a closed environment at room temperature and are easy to transport and store.

[0051] According to the embodiment of the present invention, the utilization of carbon dioxide in flue gas, at normal temperature and pressure, the partial pressure of CO2 is low, so the carboxylic acid in the solution continuously reacts with sodium bicarbonate, gradually releasing CO2 so that its concentration in the space continues to rise, and the emulsion system or solid phase system that absorbs CO2 returns to the initial carboxylate micelle solution state. Beneficial effects

[0052] The present invention provides a capture system, which is a composition for a carbon dioxide capture agent or a carbon dioxide capture agent, which has the following advantages:

[0053] 1. The capture system has a high capture capacity of 5 mg / g to 50 mg / g, excellent performance, green and environmentally friendly, and is different from the currently commercially available amine absorbents.

[0054] 2. The capture system is always in liquid or solid form, enabling the transportation and storage of flue gas CO2. In a closed environment at room temperature, CO2 can be stably stored for a long time.

[0055] 3. The capture system provided by the present invention is a new type of flue gas carbon dioxide capture agent. The carboxylate capture agent is widely available from nature and is relatively low in price. It is a potential substitute for amine absorbents and also expands the utilization of CO2 in flue gas.

[0056] The present invention also provides a method for capturing, storing and utilizing carbon dioxide in flue gas, which has the following characteristics:

[0057] 1. In response to the major national demand for CO2 energy conservation and emission reduction, the present invention proposes a method for capturing, storing and utilizing CO2 in flue gas. This method helps alleviate the climate change problem caused by CO2 emitted by industrial point sources and helps solve the environmental pollution problem caused by greenhouse gases.

[0058] 2. After capturing CO2, the system reversibly releases CO2 at room temperature and pressure, achieving efficient CO2 conversion and generating economic benefits. The release process is a reversible reaction that requires little or no external energy. BRIEF DESCRIPTION OF THE DRAWINGS

[0059] Figure 1 is a digital photograph of the saturated carboxylate aqueous solution in the present invention before and after capturing CO2: a, b, c, d, e, and f are the structural formulas of sodium heptanoate, sodium octanoate, sodium nonanoate, sodium decanoate, sodium undecanoate, and sodium laurate, respectively; g, h, I, j, k, and l represent the morphology of the sodium carboxylate solution before capturing CO2; m, n, o, p, q, and r represent the morphology of the capture agent after capturing CO2, respectively.

[0060] Figure 2 shows the capture performance data of the capture agent: the middle line in Figure 2(a) represents the C1-C 12 The capture performance of the carboxylate salt system, the top line 10wt% C8-C 11 Figure 2(b) shows the capture performance of carboxylate aqueous solution, the bottom black line represents the systematic error; Figure 2(b) shows the capture performance of sodium octanoate aqueous solution with a mass fraction of 5wt% at different temperatures and partial pressures, the flat line represents the systematic error; Figure 2(c) shows the critical partial pressure test of CO2 capture by sodium octanoate aqueous solution; Figure 2(d) shows the regeneration performance test of sodium octanoate aqueous solution in three cycles of bubbling CO2 / N2.

[0061] Figure 3 (a), (b), (c), and (d) respectively represent the critical partial pressure performance tests of CO2 capture of aqueous solutions of sodium nonanoate, sodium decanoate, sodium undecanoate, and sodium laurate.

[0062] In Figure 4, (a), (c), (d) and (e) respectively represent the three-cycle regeneration performance tests of sodium nonanoate, sodium decanoate, sodium undecanoate and sodium laurate aqueous solutions in bubbling pure CO2 / N2; Figure 4(b) represents the three-cycle regeneration performance tests of sodium nonanoate salt aqueous solution in bubbling simulated flue gas CO2 / N2; Figure 4(f) shows the capture and release performance of sodium octanoate, sodium nonanoate, sodium decanoate, sodium undecanoate and sodium laurate aqueous solutions on simulated flue gas.

[0063] Figure 5 is a digital photograph of the carboxylate aqueous solution in the present invention before and after capturing CO2: wherein a, b, c, d, e, and f are sodium decanoate, sodium 2-decenoate, sodium 10-hydroxy-2-decenoate, sodium 9-decenoate, sodium 4-decenoate, sodium 10-hydroxy-decenoate, and structural formula, respectively; g, h, I, j, k, and l represent the morphology of the sodium carboxylate solution before capturing CO2; m, n, o, p, q, and r represent the morphology of the capture agent after capturing CO2.

[0064] Figure 6 shows the performance data of the collector: the upper broken line in Figure 6(a) indicates the C 10 The capture performance of the carboxylate salt system, the bottom black line represents the system error; Figure 6 (b) shows the critical partial pressure test of CO2 capture by a 5wt% mass fraction of 4-decenoic acid sodium salt aqueous solution.

[0065] Figure 7 is a digital photograph of the carboxylate aqueous solution in the present invention before and after capturing CO2: wherein a, b, c, d, e, and f are the structural formulas of sodium octadecanoate, sodium oleate (9-octadecenoic acid), sodium linoleate (9,12-octadecadienoic acid), sodium ricinoleate, 12-hydroxy-sodium octadecanoate, and 18-hydroxy-sodium octadecanoate, respectively; g, h, I, j, k, and l represent the morphology of the sodium carboxylate solution before capturing CO2; m, n, o, p, q, and r represent the morphology of the sodium carboxylate solution after capturing CO2, respectively.

[0066] Figure 8 shows the performance data of the collector: the upper broken line in Figure 8(a) indicates the C 18 The capture performance of the carboxylate salt system is shown in Figure 8(b). The black line at the bottom represents the system error. Figure 8(b) shows the capture performance of a 5 wt% sodium oleate aqueous solution at different temperatures. The flat line represents the system error. Figures 8(c), (e), and (f) respectively show the critical partial pressure performance tests of sodium linoleate, sodium oleate, and sodium ricinoleate aqueous solutions for capturing CO2. Figure 8(d) shows the regeneration performance test of sodium linoleate aqueous solution in three cycles of bubbling simulated flue gas CO2 / N2.

[0067] Figure 9 is a digital photograph of the carboxylate aqueous solution in the present invention before and after capturing CO2: wherein a, b, c, d, e, and f are the structural formulas of sodium benzoate, sodium phenylpropionate, sodium 4-phenylbutyrate, sodium 5-phenylvalerate, sodium 6-phenylhexanoate, and sodium 8-phenyloctanoate, respectively; g, h, I, j, k, and l represent the morphology of the sodium carboxylate solution before capturing CO2; m, n, o, p, q, and r represent the morphology of the sodium carboxylate solution after capturing CO2, respectively.

[0068] Figure 10 shows the performance data of the collector: the upper broken line in Figure 10(a) represents the capture performance of a 5 wt% C1-C8 carboxylic acid salt system, and the bottom black line represents the system error; Figure 10(b) shows the conductivity test of a 5 wt% 5-phenylvaleric acid sodium salt aqueous solution capturing CO2 gases at different partial pressures. DETAILED DESCRIPTION

[0069] The following will further describe the capture agent of the present invention, its preparation method, and its application in detail with reference to specific examples. It should be understood that the following examples are merely exemplary illustrations and explanations of the present invention and should not be construed as limiting the scope of protection of the present invention. All technologies implemented based on the above content of the present invention are encompassed within the scope of protection intended by the present invention.

[0070] Example 1: Preparation of a 5 wt% aqueous solution of sodium heptanoate (C7:0)

[0071] 0.5 g of sodium heptanoate and 9.5 g of deionized water were weighed and added into a 20 ml small glass bottle in sequence, and ultrasonicated for 10 minutes to obtain a uniform sodium heptanoate aqueous solution with a mass fraction of 5 wt%.

[0072] Example 2: Preparation of sodium octanoate solutions with mass fractions of 5 wt % and 10 wt %, respectively.

[0073] Weigh 0.5g / 1g of sodium octanoate and 9.5g / 9g of deionized water, add them into a 50ml colorimetric tube in sequence, and sonicate for 10 minutes to obtain uniform sodium octanoate salt aqueous solutions (C8:0) with mass fractions of 5wt% and 10wt%, respectively.

[0074] Example 3: Preparation of sodium nonanoate solutions with mass fractions of 5 wt% and 10 wt% respectively

[0075] Weigh 0.5g / 1g of sodium nonanoate and 9.5g / 9g of deionized water, add them into a 50ml colorimetric tube in sequence, and sonicate for 10 minutes to obtain uniform sodium nonanoate aqueous solutions (C9:0) with mass fractions of 5wt% and 10wt%, respectively.

[0076] Example 4: Preparation of sodium decanoate solutions with mass fractions of 5 wt% and 10 wt% respectively

[0077] Weigh 0.5g / 1g of sodium decanoate and 9.5g / 9g of deionized water, add them into a 50ml colorimetric tube in sequence, and sonicate for 10 minutes to obtain uniform sodium decanoate salt aqueous solutions (C10:0) with mass fractions of 5wt% and 10wt%, respectively.

[0078] Example 5: Preparation of sodium undecanoate solutions with mass fractions of 5 wt% and 10 wt% respectively

[0079] Weigh 0.447 g / 0.894 g of undecanoic acid, 0.096 g / 0.192 g of NaOH, and 9.46 g / 8.91 g of deionized water, add them sequentially into a 50 ml colorimetric tube, and sonicate for 10 min to obtain uniform aqueous solutions of undecanoic acid sodium salt (C11:0) with mass fractions of 5 wt % and 10 wt %, respectively.

[0080] Example 6: Preparation of sodium laurate solutions with mass fractions of 5 wt% and 10 wt%

[0081] Weigh 0.5g / 1g of sodium laurate and 9.5g / 9g of deionized water, add them into a 50ml colorimetric tube in sequence, and sonicate for 10 minutes to obtain uniform sodium laurate aqueous solutions with mass fractions of 5wt% and 10wt%, respectively.

[0082] Example 7: Preparation of a 5 wt% aqueous solution of 2-decenoic acid sodium salt (C10:1, ω-8)

[0083] Weigh 0.5 g of sodium 2-decenoate and 9.5 g of deionized water, add them into a 50 ml small glass bottle in sequence, and ultrasonicate for 10 minutes to obtain a uniform sodium 2-decenoate aqueous solution with a mass fraction of 5 wt%.

[0084] Example 8: Preparation of a 5 wt% aqueous solution of sodium 10-hydroxy-2-decenoate (10-OH, C10:1, ω-8).

[0085] Weigh 0.5 g of sodium 10-hydroxy-2-decenoate and 9.5 g of deionized water, add them into a 50 ml colorimetric tube in sequence, and ultrasonicate for 10 minutes to obtain a uniform 10-hydroxy-2-decenoic acid sodium salt aqueous solution with a mass fraction of 5 wt% and 10 wt%.

[0086] Example 9: Preparation of 5 wt% sodium 9-decenoate solution (C10:0, ω-1)

[0087] Weigh 0.5 g of sodium 9-decenoate and 9.5 g of deionized water, add them into a 50 ml colorimetric tube in sequence, and ultrasonicate for 10 minutes to obtain a uniform 5 wt% aqueous solution of sodium 9-decenoate.

[0088] Example 10: Preparation of 5 wt% 4-decenoic acid solution (C10:0, ω-6)

[0089] Weigh 0.5 g of 4-decenoic acid and 9.5 g of deionized water, add them into a 50 ml colorimetric tube in sequence, and ultrasonicate for 10 minutes to obtain a uniform sodium decanoate aqueous solution with a mass fraction of 5 wt%.

[0090] Example 11: Preparation of 5 wt% 10-hydroxy-sodium decanoate solution (10-OH, C10:0)

[0091] Weigh 0.5 g of sodium 10-hydroxydecanoate and 9.5 g of deionized water, add them into a 50 ml colorimetric tube in sequence, and sonicate for 10 minutes to obtain a uniform 10-hydroxydecanoic acid sodium salt aqueous solution with a mass fraction of 5 wt%.

[0092] Example 12: Preparation of a 5 wt% aqueous solution of sodium oleate (C18:1, ω-9)

[0093] Weigh 0.5 g of sodium oleate and 9.5 g of deionized water, add them into a 50 ml small glass bottle in sequence, and ultrasonicate for 10 minutes to obtain a uniform sodium oleate salt aqueous solution with a mass fraction of 5 wt%.

[0094] Example 13: Preparation of sodium linoleate aqueous solution (C18:2, ω-6) with a mass fraction of 5 wt%.

[0095] Weigh 0.5 g of sodium 10-hydroxy-2-decenoate and 9.5 g of deionized water, add them into a 50 ml colorimetric tube in sequence, and ultrasonicate for 10 minutes to obtain a uniform 10-hydroxy-2-decenoic acid sodium salt aqueous solution with a mass fraction of 5 wt%.

[0096] Example 14: Preparation of 5 wt% sodium ricinoleate solution (12-OH, C18:1, ω-9)

[0097] Weigh 0.5 g of sodium ricinoleate and 9.5 g of deionized water, add them into a 50 ml colorimetric tube in sequence, and ultrasonicate for 10 minutes to obtain a uniform sodium ricinoleate aqueous solution with a mass fraction of 5 wt%.

[0098] Example 15: Preparation of 5 wt% 12-hydroxy-octadecanoic acid sodium solution (12-OH, C18:0)

[0099] Weigh 0.5 g of sodium 12-hydroxyoctadecanoate and 9.5 g of deionized water, add them into a 50 ml colorimetric tube in sequence, and sonicate for 10 minutes to obtain a uniform 12-hydroxyoctadecanoic acid sodium salt aqueous solution with a mass fraction of 5 wt%.

[0100] Example 16: Preparation of 5 wt% 18-hydroxy-octadecanoic acid sodium solution (18-OH, C18:0)

[0101] Weigh 0.5 g of sodium 18-hydroxyoctadecanoate and 9.5 g of deionized water, add them into a 50 ml colorimetric tube in sequence, and sonicate for 10 minutes to obtain a uniform sodium 18-hydroxyoctadecanoate saline solution with a mass fraction of 5 wt%.

[0102] Example 17: Preparation of a 5 wt% aqueous solution of sodium benzoate

[0103] Weigh 0.5 g of sodium benzoate and 9.5 g of deionized water, add them into a 50 ml small glass bottle in sequence, and ultrasonicate for 10 minutes to obtain a uniform sodium benzoate salt aqueous solution with a mass fraction of 5 wt%.

[0104] Example 18: Preparation of a sodium phenylpropionate aqueous solution with a mass fraction of 5 wt%.

[0105] Weigh 0.5 g of sodium phenylpropionate and 9.5 g of deionized water, add them into a 50 ml colorimetric tube in sequence, and ultrasonicate for 10 minutes to obtain a uniform sodium phenylpropionate sodium salt aqueous solution with a mass fraction of 5 wt%.

[0106] Example 19: Preparation of 5 wt% aqueous solution of sodium phenylbutyrate

[0107] Weigh 0.5 g of sodium phenylbutyrate and 9.5 g of deionized water, add them into a 50 ml colorimetric tube in sequence, and ultrasonicate for 10 minutes to obtain a uniform sodium phenylbutyrate salt aqueous solution with a mass fraction of 5 wt%.

[0108] Example 20: Preparation of 5wt% 5-phenyl-sodium valerate solution

[0109] Weigh 0.5 g of sodium 5-phenyl-valerate and 9.5 g of deionized water, add them into a 50 ml colorimetric tube in sequence, and sonicate for 10 minutes to obtain a uniform 5 wt % aqueous solution of sodium 5-phenyl-valerate.

[0110] Example 21: Preparation of 5 wt% 6-phenyl-sodium hexanoate solution

[0111] Weigh 0.5 g of sodium 6-phenylhexanoate and 9.5 g of deionized water, add them into a 50 ml colorimetric tube in sequence, and sonicate for 10 minutes to obtain a uniform sodium 6-phenylhexanoate saline solution with a mass fraction of 5 wt%.

[0112] Example 22: Preparation of 5 wt% 8-phenyl-octanoic acid sodium solution

[0113] Weigh 0.5 g of sodium 8-phenyl octanoate and 9.5 g of deionized water, add them into a 50 ml colorimetric tube in sequence, and sonicate for 10 minutes to obtain a uniform sodium 8-phenyl octanoate saline solution with a mass fraction of 5 wt%.

[0114] As shown in the digital photos (g), (h), (I), (j), (k), and (l) in Figure 1, they are physical pictures of an aqueous solution of sodium heptanoate, an aqueous solution of sodium octanoate, an aqueous solution of sodium nonanoate, an aqueous solution of sodium decanoate, an aqueous solution of sodium undecanoate, and an aqueous solution of sodium laurate, respectively. All of the above aqueous solutions are uniform and transparent micellar solutions.

[0115] Test Example 1: CO2 capture performance test

[0116] Sample 1: 5 wt% aqueous solution of sodium heptanoate prepared in Example 1;

[0117] Sample 2: 5 wt % and 10 wt % aqueous solutions of sodium octanoate prepared in Example 2;

[0118] Sample 3: 5 wt % and 10 wt % aqueous solutions of sodium nonanoate prepared in Example 3;

[0119] Sample 4: 5 wt % and 10 wt % aqueous solutions of sodium caprate prepared in Example 4;

[0120] Sample 5: 5 wt % and 10 wt % aqueous solutions of sodium undecanoate prepared in Example 5;

[0121] Sample 6: 5 wt % and 10 wt % aqueous solutions of sodium laurate prepared in Example 6.

[0122] Sample 7: 5 wt% aqueous solution of 2-decenoic acid sodium salt prepared in Example 7;

[0123] Sample 8: 5 wt% aqueous solution of 10-hydroxy-2-decenoic acid sodium salt prepared in Example 8;

[0124] Sample 9: 5 wt% aqueous solution of 9-decenoic acid sodium salt prepared in Example 9;

[0125] Sample 10: 5 wt% aqueous solution of 4-decenoic acid sodium salt prepared in Example 10;

[0126] Sample 11: 5 wt% aqueous solution of 10-hydroxy-decanoic acid sodium salt prepared in Example 11;

[0127] Sample 12: 5 wt% aqueous solution of sodium oleate prepared in Example 12;

[0128] Sample 13: 5 wt% aqueous solution of sodium linoleate prepared in Example 13;

[0129] Sample 14: 5 wt% aqueous solution of sodium ricinoleate prepared in Example 14;

[0130] Sample 17: 5 wt% aqueous solution of sodium benzoate prepared in Example 17;

[0131] Sample 18: 5 wt% aqueous solution of sodium phenylpropionic acid salt prepared in Example 18;

[0132] Sample 19: 5 wt% aqueous solution of sodium phenylbutyrate prepared in Example 19;

[0133] Sample 20: 5 wt% aqueous solution of 5-phenyl-pentanoic acid sodium salt prepared in Example 20;

[0134] Sample 21: 5 wt% aqueous solution of 6-phenylhexanoic acid sodium salt prepared in Example 21;

[0135] Sample 22: 5 wt% aqueous solution of 8-phenyloctanoic acid sodium salt prepared in Example 22.

[0136] The above 22 samples were used to test the CO2 capture performance respectively. Among them, the performance test method of sample 1 is as follows: 10g of 5wt% sodium heptanoate aqueous solution was weighed and placed in a sealed vial, the vial mouth was sealed with a rubber stopper and two needles, one needle was inserted into the solution, and the other needle was placed above the liquid surface, connected to the surrounding environment, and a syringe tube filled with cotton was installed to prevent liquid loss. Pure CO2 or simulated flue gas (wherein, the components of the simulated flue gas are N2 (74.89%), CO2 (20%), O2 (5%), CO (20ppm), SO2 (600ppm) and NO2 (500ppm)) was continuously bubbled in at a rate of 30mL / min under stirring for 60min to allow the solution to absorb CO2 to saturation, thereby achieving CO2 capture, and the mass change of the bottle during the CO2 capture process was recorded by weighing method to obtain the CO2 capture performance.

[0137] At the same time, the CO2 capture performance of sample 2-22 and pure water was tested using the same method.

[0138] The CO2 capture performance of the above samples 2-6 is shown in Figure 2. As can be seen from Figure 2(a), the six samples (C8-C 12 The CO2 capture capacity of samples 2-6 (C8-C 11 ) has a higher CO2 capture capacity per unit mass. When the corresponding concentration is 10wt%, the capture capacity is higher than 10mg / g, and the highest can reach 12.2mg / g; the CO2 capture capacity per unit mass of sodium monocarboxylates of C1-C7) is lower.

[0139] The capture performance of CO2 in the flue gas of sample 2-6 is shown in Figure 4. As can be seen from Figure 4(f), the mass of CO2 in the flue gas captured by sample 2-6 is lower than the captured pure CO2, which are 1.18 mg / g, 1.94 mg / g, 3.72 mg / g, 2.02 mg / g and 2.87 mg / g, respectively, accounting for 15.6%, 22.8%, 38.9%, 21.5% and 28.8% of the captured pure CO2, respectively.

[0140] As shown in Figure 2(b), the effects of different temperatures and CO2 partial pressures on the CO2 capture performance of test sample 2 are shown. It is found that the reaction occurring in the capture process is an exothermic reaction. The higher the temperature, the lower the capture performance. When the temperature reaches about 80°C, the CO2 capture performance is close to that of pure water. At the same time, according to Henry's law, as the CO2 partial pressure increases, the capture performance improves.

[0141] The CO2 capture performance of the above samples 7-11 is shown in Figure 6. It can be seen from Figure 6(a) that the CO2 capture capacity of the five samples is higher than that of pure water, and all have the performance of capturing CO2. Among them, the CO2 capture capacity per unit mass of sample 7-9 is higher, and the performance of unsaturated sodium decenoate is close to that of sodium decanoate. When the corresponding concentration is 5wt%, the capture capacity is higher than 9mg / g, and the maximum can reach 10.49mg / g. The CO2 capture capacity per unit mass of samples 10-11 is lower and slightly higher than pure water.

[0142] The CO2 capture performance of the above samples 12-14 is shown in Figure 8. As can be seen from Figure 8(a), the CO2 capture performance of the aqueous solutions of sodium oleate, sodium linoleate and sodium ricinoleate in the three samples is similar. When the corresponding concentration is 5wt%, the capture amount is all higher than 9mg / g, and the highest can reach 10.11mg / g. However, sodium octadecanoate, sodium 12-hydroxy-octadecanoate and sodium 18-hydroxy-octadecanoate are insoluble in water and therefore do not have the ability to capture CO2.

[0143] Based on this, it can be inferred that when the concentration of the aqueous solution of sodium oleate, sodium linoleate and sodium ricinoleate salts is 30wt%, the corresponding CO2 capture capacity is greater than 50mg / g.

[0144] As shown in Figure 8(b), the effect of different temperatures on the CO2 capture performance of test sample 13 is shown. It is found that the reaction occurring in the capture process is an exothermic reaction. The higher the temperature, the lower the capture performance. When the temperature reaches about 80°C, the CO2 capture performance is close to that of pure water.

[0145] The CO2 capture performance of the above samples 17-22 is shown in Figure 10. As can be seen from Figure 10(a), the CO2 capture performance of samples 17-22 gradually increases, among which the CO2 capture performance of samples 20-22 is relatively high. When the corresponding concentration is 5wt%, the capture amount is higher than 9 mg / g, and the highest can reach 10.11 mg / g. Sodium octadecanoate, 12-hydroxy-sodium octadecanoate and 18-hydroxy-sodium octadecanoate are insoluble in water, so the CO2 capture performance is similar to that of pure water.

[0146] Test Example 2: Stability test of CO2 storage by capture agent

[0147] Sample 1: Sample 2 in Test Example 1 after capturing CO2.

[0148] Sample 2: Sample 3 in Test Example 1 after capturing CO2.

[0149] Sample 3: Sample 4 in Test Example 1 after capturing CO2.

[0150] Sample 4: Sample 5 in Test Example 1 after capturing CO2.

[0151] Sample 5: Sample 6 in Test Example 1 after capturing CO2.

[0152] Sample 6: Sample 7 in Test Example 1 after capturing CO2.

[0153] Sample 7: Sample 9 in Test Example 1 after capturing CO2.

[0154] Sample 8: Sample 10 in Test Example 1 after capturing CO2.

[0155] Sample 9: Sample 12 in Test Example 1 after capturing CO2.

[0156] Sample 10: Sample 13 in Test Example 1 after capturing CO2.

[0157] Sample 11: Sample 14 in Test Example 1 after capturing CO2.

[0158] Sample 12: Sample 20 in Test Example 1 after capturing CO2.

[0159] Sample 13: Sample 21 in Test Example 1 after capturing CO2.

[0160] Sample 14: Sample 22 in Test Example 1 after capturing CO2.

[0161] The above sample refers to the solution that reaches saturation by using the CO2 capture performance test method in Test Example 1.

[0162] The stability of CO2 sealed by the above 14 samples was tested separately. Among them, the stability test method of CO2 sealed by the samples is as follows: the samples to be tested are placed in an environment at room temperature of 20-30°C for 30 days, and no stratification occurs and their morphology still remains in the emulsion form or solid phase state, indicating that the capture agent for capturing CO2 in the present invention is easy to store and has stable properties.

[0163] Test Example 3: Critical partial pressure performance test for CO2 capture

[0164] Sample 1: 5 wt% aqueous solution of sodium octanoate prepared in Example 2.

[0165] Sample 2: 5 wt % aqueous solution of sodium nonanoate prepared in Example 3.

[0166] Sample 3: 5 wt% aqueous solution of sodium caprate prepared in Example 4.

[0167] Sample 4: 5 wt% aqueous solution of sodium undecanoate prepared in Example 5.

[0168] Sample 5: 5 wt% aqueous solution of sodium lauric acid salt prepared in Example 6.

[0169] Sample 6: 5 wt% aqueous solution of sodium salt of 4-decenoic acid prepared in Example 10.

[0170] Sample 7: 5 wt% aqueous solution of sodium oleate prepared in Example 12.

[0171] Sample 8: 5 wt% aqueous solution of sodium linoleic acid prepared in Example 13.

[0172] Sample 9: 5 wt% aqueous solution of sodium ricinoleate prepared in Example 14.

[0173] Sample 10: 5 wt% aqueous solution of 5-phenylvaleric acid sodium salt prepared in Example 20.

[0174] Prepare CO2 gas at different partial pressures by filling two airbags with carbon dioxide and nitrogen, respectively. Use a CO2 flowmeter and an N2 flowmeter to control the flow rates, respectively, to prepare CO2 gas at different partial pressures. For example: To prepare 20% CO2 gas, connect the airbag to the flowmeter and pass carbon dioxide into the oxygen bag at a gas flow rate of 300mL / min for 5 minutes. Then, pass nitrogen into the oxygen bag at a flow rate of 300mL / min for 20 minutes to thoroughly mix the gases in the oxygen bag. This will prepare simulated gas with a CO2 content of 20% for use. Prepare CO2 gas at partial pressures of 0, 4%, 5%, 30%, 50%, and 100% in sequence.

[0175] The CO2 critical partial pressure performance of the above 10 samples was tested respectively. The critical partial pressure performance test method is as follows: 20 ml of the sample was measured and placed in a 50 ml beaker, the bottle mouth was sealed with plastic wrap, the detection probe and temperature probe of the conductivity meter were placed below the liquid surface through the small hole, and the prepared CO2 gas with different partial pressures was bubbled into the sample through the needle tip at a gas flow rate of 30 ml / min. The sample was magnetically stirred, and the change of the conductivity of the sample over time was tested and recorded.

[0176] The changes in the electrical conductivity of the above 10 samples with different partial pressures of CO2 gas are shown in Figures 2, 3, 6, 8 and 10. It can be seen from Figure 2(c) that the critical partial pressure of CO2 captured by sample 1 is 5%. From Figures 3(a), (b), (c) and (d), it can be seen that the critical partial pressures of CO2 captured by samples 2-5 are 5%, 6%, 6% and 5%, respectively. From Figure 6(b), the critical partial pressure of sample 10 is 10%. From Figures 8(c), (e) and (f), it can be seen that samples 12-14 can all capture CO2, among which the critical partial pressures of samples 12-13 are 2% and 4%, respectively. From Figure 10(b), it can be seen that sample 20 can capture CO2 in simulated flue gas. Usually, the partial pressure of CO2 in flue gas is usually 13% to 20%. It can be seen that the capture agent in the present invention can be used to capture CO2 in flue gas.

[0177] Test Example 4: Recycling performance of the collector

[0178] Sample 1: 5 wt% aqueous solution of sodium octanoate prepared in Example 2.

[0179] Sample 2: 5 wt % aqueous solution of sodium nonanoate prepared in Example 3.

[0180] Sample 3: 5 wt% aqueous solution of sodium caprate prepared in Example 4.

[0181] Sample 4: 5 wt % aqueous solution of sodium undecanoate prepared in Example 5.

[0182] Sample 5: 5 wt% aqueous solution of sodium lauric acid salt prepared in Example 6.

[0183] Sample 6: 5 wt% aqueous solution of sodium linoleic acid prepared in Example 13.

[0184] The recycling and regeneration performance of the above 6 samples were tested respectively, and the recycling and regeneration performance test method was as follows: 20 ml of the sample was measured and placed in a 50 ml beaker, the bottle mouth was sealed with plastic wrap, the detection probe and temperature probe of the conductivity meter were placed below the liquid surface through the small hole, pure CO2 or simulated flue gas was bubbled into the sample through the needle tip, the gas flow rate was 30 ml / min, magnetic stirring was applied, the change process of the conductivity of the sample over time was tested and recorded, after the reaction was complete and the conductivity no longer changed, the gas bag containing CO2 was removed and replaced with a gas bag containing N2, N2 was bubbled into the sample through the needle tip, the change process of the conductivity of the sample over time was tested and recorded, after the reaction was complete and the conductivity no longer changed, one cycle was completed, and the change process of the conductivity of the sample over time was tested in this way for three cycles.

[0185] The test results of the cyclic regeneration performance of the above six samples are shown in Figure 2(d), Figure 4, and Figure 8. It can be seen from Figure 2(d) that after three cycles of alternating pure CO2 / N2 bubbling, the conductivity of sample 1 can still be restored to its initial state, indicating that it has good stability and the release process does not require energy.

[0186] As can be seen from Figures 4(a) and (b), the conductivity of sample 2 can still recover to its initial state after three cycles of pure CO2 / N2 and simulated flue gas / N2 bubbling respectively. As can be seen from Figures 4(c), (d) and (e), the conductivity of samples 3-5 can still recover to its initial state after three cycles of pure CO2 / N2 alternately bubbling. As can be seen from Figure 8(d), the conductivity of sample 6 can still recover to its initial state after three cycles of simulated flue gas / N2 alternately bubbling, indicating that it has good stability and the release process does not require energy.

[0187] Test Example 5: CO2 release performance of the capture agent in flue gas.

[0188] Sample 1: Sample 2 in Test Example 1.

[0189] Sample 2: Sample 3 in Test Example 1.

[0190] Sample 3: Sample 4 in Test Example 1.

[0191] Sample 4: Sample 5 in Test Example 1.

[0192] Sample 5: Sample 6 in Test Example 1.

[0193] The release performance of the above five samples after capturing CO2 in flue gas was tested separately. The release performance test method after capturing CO2 in flue gas was as follows: 0.1 g of sample was weighed and placed in the lid of a 10 mL centrifuge tube with a diameter of 0.6 cm and a height of 0.4 cm. The lid was placed in the transparent leaf chamber of a completely sealed portable photosynthetic instrument Li-6800, and the CO2 concentration in the reference chamber was set to 400 μmol*mol -1 , the cooling fan is set to low speed, and the gas flow rate is set to 200μmol*s -1 After the instrument is successfully matched, the CO2 concentration in the current sample chamber is recorded every 5 seconds. When the CO2 concentration reaches the same concentration as the reference chamber and no longer changes with time, the test is stopped. The test is repeated 3-5 times. The unit of the carbon dioxide concentration in the instrument export data is μmol*mol -1 , which is the amount of carbon dioxide per mole of gas. After unit conversion and time integration, the total amount of carbon dioxide released can be obtained. The total amount of CO2 released can be obtained through data processing.

[0194] The formula for carbon dioxide release is as follows: Where: ΔCO2: the difference between the sample chamber concentration and the reference chamber concentration (unit: μmol*mol -1 ), v: gas flow rate (unit: μmol*s -1 ), m: sample mass (unit: g).

[0195] The release performance of CO2 in the captured flue gas of the above five samples is shown in Figure 4(f). As can be seen from Figure 4(f), the release amount of samples 1-5 is equivalent to the capture amount, and the release efficiency can reach more than 90%. The release mass of sample 1 accounts for nearly 96.6% of the CO2 in the captured flue gas, which is almost completely released; the release mass of sample 2 accounts for 94.2% of the CO2 in the captured flue gas. The difference may be attributed to the release of CO2 by the sample during the sample placement process, which makes the test result smaller.

[0196] The above examples illustrate the specific embodiments of the present invention. However, the scope of protection of the present invention is not limited to the above-mentioned exemplary embodiments. Any modifications, equivalent substitutions, improvements, etc. made by those skilled in the art within the spirit and principles of the present invention shall be included in the scope of protection of the claims of the present invention.

Claims

1. A composition for a carbon dioxide capture agent, characterized in that: The composition comprises carboxylic acid, solvent and base, wherein the solvent is a good solvent for the carboxylic acid and the base, the chemical formula of the carboxylic acid is R-COOH, wherein R is a substituted or unsubstituted C4-C 21 Hydrocarbon; The substitution means that one or more H on the alkyl group is replaced by a hydrocarbon group, -OH, -COOH, an aryl group, an amino group or -X, wherein X is a halogen atom F, Cl, Br or I.

2. The composition according to claim 1, characterized in that The carboxylic acid is C8~C 18 Saturated monocarboxylic acid, C8~C 14 Polycarboxylic acid, C8~C 22 Mono- or poly-unsaturated carboxylic acids or C5-C 12 At least one of the carboxylic acids; Preferably, the base is selected from at least one of an inorganic base and an organic base; Preferably, the solvent is selected from water or a complex solvent.

3. The composition according to claim 1 or 2, characterized in that The composition also contains a carboxylate formed by carboxylic acid and a base; the mass fraction of the carboxylate is greater than 0 and less than or equal to 30%.

4. A carbon dioxide capture agent, which is specially prepared in that it comprises a solvent and a carboxylate dissolved in the solvent, wherein the mass fraction of the carboxylate is greater than 0 and less than or equal to 30%, and the carboxylate is a carboxylate formed by carboxylic acid and a base, and the solvent, carboxylic acid and base have the definitions described in any one of claims 1 to 3.

5. The collector according to claim 4, characterized in that The pH value of the carbon dioxide capture agent is 7-14; Preferably, the carbon dioxide capture agent is a transparent solution or a micellar solution.

6. A method for capturing carbon dioxide, characterized in that: The method comprises the following steps: The gas containing CO2 is contacted with the capture composition according to any one of claims 1 to 3 or the carbon dioxide capture agent according to any one of claims 4 to 5 to capture CO2.

7. The method according to claim 6, characterized in that The contact is carried out under closed conditions; After capturing CO2, the method further includes the following step: storing the capture agent containing CO2.

8. The method according to claim 6 or 7, characterized in that: After capturing CO2 or storing the capture agent containing CO2, the method further includes the following step: regenerating the capture agent. Preferably, regenerating the capture agent comprises the following steps: placing the capture agent after capturing CO2 or storing the capture agent containing CO2 in an environment with a CO2 partial pressure of less than 2% to release CO2 to obtain a regenerated capture agent.

9. The method according to claim 8, characterized in that The CO2 is released in an environment where the CO2 partial pressure is less than 1%; Preferably, the CO2 is released at a temperature of 0 to 90°C.

10. Use of a composition according to any one of claims 1 to 3, a capture agent according to any one of claims 4 to 5, or a method for capturing CO2 according to any one of claims 6 to 9 in the treatment of CO2 in waste streams in power plants, cement manufacturing, steel manufacturing, glass manufacturing, brewing, synthesis gas production, natural gas and biogas purification, ammonia synthesis or any other industrial process producing acidic gas; It is preferably used for geological utilization to enhance oil recovery and gas production; chemical utilization to prepare liquid fuels and degradable polymers; or biological utilization to convert into food, feed, chemicals and bio-CO2 gas fertilizer; or for geological storage, for example, for enhancing the mining of oil, natural gas, geothermal energy, shale gas, coalbed methane, and uranium mines, preparing liquid fuels, synthesizing polyols, methanol, carbonates, and degradable polymers, converting them into food and feed, converting them into chemicals, and using them as CO2 gas fertilizer for plants.

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