Carbon dioxide capture agent, and preparation method and application thereof

Abstract

The application discloses a carbon dioxide capturing agent and a preparation method and application thereof, relates to the technical field of chemical synthesis, and the formula of the carbon dioxide capturing agent comprises the following components: diethanolamine 2-15 mL, triethylenetetramine 6-20 mL, tetraethylenepentamine 20-80 mL, ethanolamine 2-15 mL, triethanolamine 5-20 mL, methanol 10-50 mL, polyethyleneimine 1-10 mL, piperazine 1-12 g and an initiator 2-10 mL. The carbon dioxide capturing agent can simultaneously meet the three conditions of efficient capturing, low-cost absorption and normal application (temperature 15 DEG C-30 DEG C, pressure 101 kPa), and can very properly compatibly solve the bottleneck problem of the development of the CCUS technology, i.e. economic benefits and cost.

Description

Technical Field

[0001] This invention relates to the field of chemical synthesis technology, and in particular to a carbon dioxide trapping agent, its preparation method, and its application. Background Technology

[0002] China faces increasing international pressure and domestic demand for emission reduction, continuously driving the rapid upgrade of CCUS (carbon capture, utilization, and storage) technology from a strategic reserve technology to a practical solution. Its technological positioning, development direction, and future deployment require further research. Given that my country's coal-dominated energy structure is unlikely to fundamentally change for a considerable period, CO2 emissions will remain high. CCUS technology, as an emerging technology with large-scale CO2 emission reduction potential, is widely considered a crucial technology for addressing global climate change and controlling greenhouse gas emissions. Developing CCUS technology is an important long-term technological approach for my country to reduce CO2 emissions. Based on policy guidance and practical needs, CCUS technology will become a focal technology in the coming years, making it essential to prepare for its development in this field in advance.

[0003] Liquid amine absorption is a widely used method in industry, offering high selectivity for CO2 absorption, but it suffers from drawbacks such as high material consumption and equipment corrosion. Pre-combustion capture (CCUS) and post-combustion capture (CCUS) technologies are mature and economically feasible, but their high cost—averaging over $30 per ton of CO2—severely hinders CCUS deployment. Economic efficiency is a key area of ​​future research in CO2 capture technology. Furthermore, low-concentration CO2 emission sources require more investment in purification and compression compared to high-concentration sources, while high-concentration emission sources have lower CO2 capture costs. Consequently, most large-scale CCUS demonstration bases in China are currently located near factories with high CO2 emissions, such as coal-fired power plants, and globally, most of the earliest CCUS deployments are in coal-fired power plants.

[0004] The chemical absorption method using alcoholic amines works by utilizing the reversible chemical reaction between organic alcoholic amines and CO2 to remove CO2 from industrial exhaust gases. Due to the strong electrostatic and hydrogen bonding interactions present in the products, the viscosity of the organic alcoholic amines increases dramatically after absorbing CO2. Therefore, organic alcoholic amines typically need to be diluted in low-viscosity physical solvents such as water, ethanol, or sulfolane.

[0005] A novel design concept of "chemical absorbent + chemical diluent" was proposed, resulting in the construction of PEI / TEPA+[emim][AcO] and PEI+[P 4444The [2-F-PhO] mixed absorbent not only has a high CO2 absorption capacity and a fast CO2 absorption rate, but its viscosity change after CO2 absorption is also less significant than that of pure PEI / TEPA. On the other hand, PEI / TEPA and [emim][AcO] / [P]... 4444 The volatility of [2-F-PhO] is extremely low, making PEI / TEPA+[emim][AcO]P 4444 The [2-F-PhO] mixed absorbent has a high degree of safety and environmental friendliness in CO2 capture processes.

[0006] Due to the simplicity and strong absorption capacity of amine solutions, numerous laboratory experiments have been conducted by researchers in recent years. Examples include: ① The 2M MAPA / 5M DEEA system, characterized by low vapor pressure, high loading capacity, energy consumption of 2.4 GJ / ton of CO2, and high viscosity. ② The 2MBDA / 4M DEEA system, characterized by a 48% increase in cycling capacity, but with high viscosity. ③ The 5M TETA+DEEA system, characterized by a 40% higher cycling load, reaching 0.92 mol / mol, and energy consumption reduced by 30% compared to MEA. ④ The DETA+sulfolane system, characterized by a 35% higher cycling load, but prone to phase separation. ⑤ The PMDETA+DETA system, characterized by a high loading capacity of 0.62 mol / mol, a lower phase rich in 99.7% CO2, and low-temperature phase separation. ⑥ A temperature-controlled lipophilic amine solution system, characterized by a low desorption temperature (80℃) and energy consumption of 2.0 GJ / ton of CO2. ⑦ Three systems: DMCA 15% + MCA 15%; DMCA 25% + PZ 5%; and DSBA 15% + MCA 15%. These systems are characterized by low desorption temperature (80℃), fast absorption rate, and a net cycling load approximately 1.46 times higher than 30% MEA. The regeneration energy consumption is 2.48 GJ / ton of CO2. ⑧ The DMX-1 system is characterized by low heat of reaction (approximately 60 KJ / mol), good thermal stability, easy separation, and an energy consumption of 2.3 GJ / ton of CO2.

[0007] NH3, when combined with organic solvents such as ethanol, 1-propanol, and N,N-dimethylformamide (DMF), can achieve a solid-phase CO2 enrichment of up to 54%. Perry et al. investigated a favorable liquid-solid phase change system: 1,3-bis(3-aminopropyl)-1,1,3,3-tetrasiloxane (GAP-0). After loading CO2, the absorbent transforms from a low-viscosity liquid into a solid enriched with a large amount of CO2. This system's process model reduced energy consumption from 30% to 18% of the MEA process. Recently, researchers have studied novel polyamine absorbents (diethanolamine DEA, 2-amino-2-methyl-1-propanol AMP, dimethyldiethanolamine DMEE) using ionic liquids (tetramethylammonium glycine, [N1111][Gly]) as solvents, which exhibit advantages such as easy liquid-solid phase change, fast absorption rate, large loading capacity, and low desorption temperature. Meanwhile, the liquid-solid phase separation behavior of polyamines (such as diethylenetriamine DETA, triethylenetetramine TETA, tetraethylenepentamine TEPA) after loading CO2 in organic solvents such as ethanol, diethylene glycol dimethyl ether, and N-methylpyrrolidone is also very obvious. In addition, this system has the advantages of fast absorption rate, large loading capacity and low desorption temperature.

[0008] Based on the above analysis of the technologies and processes for synthesizing amine solutions, it can be seen that some of the reagents prioritize high CO2 absorption capacity, others prioritize low desorption energy consumption and temperature, and still others prioritize viscosity reduction to improve mass transfer efficiency. Regardless of the specific focus, currently no reagent can comprehensively address the issues of high adsorption capacity, high desorption rate, high reusability, and low desorption energy consumption in CO2 absorbents. Furthermore, purchasing these reagents at the industrial level requires significant economic investment, severely hindering their market adoption. Currently, these reagents are only suitable for laboratory research and not for field implementation. Therefore, there is a current lack of widely available, high-efficiency, low-cost CO2 traps. Thus, there is an urgent need to develop a high-efficiency, low-cost CO2 trap under normal operating conditions. Summary of the Invention

[0009] The purpose of this invention is to provide a carbon dioxide capture agent, its preparation method, and its application, which can simultaneously meet the three conditions of high-efficiency capture, low-cost absorption, and normalized application (temperature -15℃ to 30℃, pressure 101kPa). This effectively addresses the current bottleneck problem hindering the development of CCUS technology—economic efficiency and cost. Once the economic efficiency and cost issues are resolved, it will unleash domestic demand for CCUS, broaden and deepen the application of CCUS technology, and give it a competitive edge in the market.

[0010] To achieve the above objectives, the present invention provides the following technical solution:

[0011] The present invention provides a carbon dioxide trapping agent, wherein the formulation of the carbon dioxide trapping agent comprises: 2-15 mL of diethanolamine, 6-20 mL of triethylenetetramine, 20-80 mL of tetraethylenepentamine, 2-15 mL of ethanolamine, 5-20 mL of triethanolamine, 10-50 mL of methanol, 1-10 mL of polyethyleneimine, 1-12 g of piperazine, and 2-10 mL of initiator.

[0012] Preferably, the carbon dioxide trapping agent comprises: 8-15 mL of diethanolamine, 10-20 mL of triethylenetetramine, 30-80 mL of tetraethylenepentamine, 6-15 mL of ethanolamine, 5-20 mL of triethanolamine, 20-50 mL of methanol, 2-10 mL of polyethyleneimine, 5-12 g of piperazine, and 5-10 mL of initiator.

[0013] Preferably, the initiator is N-methyldiethanolamine.

[0014] This invention also provides a method for preparing a carbon dioxide trap, the method comprising the following steps:

[0015] Add methanol and piperazine to the reaction vessel and stir at room temperature. After the piperazine is completely dissolved, add ethanolamine, diethanolamine, triethylenetetramine, tetraethylenepentamine and triethanolamine in sequence to the reaction vessel. Stir for 5 to 10 minutes after each reagent is added before adding the next one. Then add polyethyleneimine and initiator. When the solution becomes a completely homogeneous and transparent solution, stop stirring and cool to room temperature to obtain the target product.

[0016] Preferably, the stirring conditions include: a stirring speed of 50 r / min to 60 r / min and a stirring time of 5 min to 10 min.

[0017] The present invention also provides an application of a carbon dioxide capture agent, wherein the maximum saturated CO2 absorption capacity of the carbon dioxide capture agent is 95.1 mg / g, which is 8 to 9 times that of monoethanolamine (MEA) under the same conditions; the maximum repeatable absorption capacity is 91.4%, and the resolution rate is 98%.

[0018] Furthermore, when the carbon dioxide capture agent is used at a temperature of -15℃ to 30℃ and a pressure of 101kPa, it can capture CO2 with a concentration of less than 5% in the air. After being refrigerated and left to stand at -15℃ for 120 days, it still maintains high low-temperature stability without stratification, turbidity, or crystallization.

[0019] The technical effects and advantages of this invention are as follows:

[0020] 1. The high-efficiency, low-cost carbon dioxide capture agent prepared by this invention has the characteristics of good thermal stability, fast absorption rate, good selectivity, high capacity, and good recyclability. Its CO2 absorption capacity exceeds that of traditional organic alcohol amine aqueous solutions, and the maximum saturated CO2 absorption capacity can reach 21g, which is 8 to 9 times that of monoethanolamine (MEA) under the same conditions. Furthermore, testing results from a third-party institution with CMA accreditation show that all performance indicators of the independently developed amine solution are superior to similar products with high market share.

[0021] 2. The amine solution obtained after the saturated adsorption of carbon dioxide by the trapping agent prepared in this invention, after being refrigerated at 6°C, showed no stratification, turbidity, or crystallization. Tests showed that the independently developed amine solution maintained high low-temperature stability at -15°C and after standing for 120 days, showing no stratification, turbidity, or crystallization.

[0022] Other features and advantages of the invention will be set forth in the following description, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention may be realized and obtained by means of the structures pointed out in the description and the drawings. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 This is a diagram illustrating the reaction mechanism between polyethyleneimine (PEI) and carbon dioxide (CO2).

[0025] Figure 2 A schematic diagram of a device for testing CO2 saturation absorption. Detailed Implementation

[0026] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0027] The flowchart shown in the attached diagram is merely an illustrative example and does not necessarily include all steps. For example, some steps may be broken down, while others may be combined or partially combined; therefore, the actual execution order may change depending on the specific circumstances.

[0028] The terms "first," "second," etc., used in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such use of data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented in sequences other than those illustrated or described herein.

[0029] Furthermore, the terms “comprising” and “having”, and any variations thereof, are intended to cover non-exclusive inclusion, such that a process, method, system, product, or device that includes a series of steps or sub-modules is not necessarily limited to those steps or sub-modules that are explicitly listed, but may include other steps or sub-modules that are not explicitly listed or that are inherent to such process, method, product, or device.

[0030] To address the shortcomings of existing technologies, this invention discloses a carbon dioxide trapping agent, the formulation of which includes: 2-15 mL of diethanolamine, 6-20 mL of triethylenetetramine, 20-80 mL of tetraethylenepentamine, 2-15 mL of ethanolamine, 5-20 mL of triethanolamine, 10-50 mL of methanol, 1-10 mL of polyethyleneimine, 1-12 g of piperazine, and 2-10 mL of N-methyldiethanolamine as an initiator.

[0031] Furthermore, the carbon dioxide trapping agent comprises the following components: 8-15 mL of diethanolamine, 10-20 mL of triethylenetetramine, 30-80 mL of tetraethylenepentamine, 6-15 mL of ethanolamine, 5-20 mL of triethanolamine, 20-50 mL of methanol, 2-10 mL of polyethyleneimine, 5-12 g of piperazine, and 5-10 mL of initiator.

[0032] This invention also discloses a method for preparing a carbon dioxide trap, comprising the following steps:

[0033] Add methanol and piperazine to the reaction vessel and stir. After the piperazine is completely dissolved, add ethanolamine, diethanolamine, triethylenetetramine, tetraethylenepentamine and triethanolamine in sequence to the reaction vessel. After each reagent is added, stir at a speed of 50 r / min to 60 r / min for 5 min to 10 min before adding the next reagent. Then add polyethyleneimine and the initiator N-methyldiethanolamine. When the solution becomes a completely homogeneous and transparent solution, stop stirring and cool to room temperature to obtain the target product.

[0034] The present invention also discloses the application of a carbon dioxide capture agent, wherein the maximum saturated CO2 absorption capacity of the carbon dioxide capture agent is 95.1 mg / g, which is 8 to 9 times that of monoethanolamine (MEA) under the same conditions; the maximum repeatable absorption capacity is 91.4%, and the resolution rate is 98%.

[0035] Furthermore, when used at temperatures ranging from -15°C to 30°C and pressures of 101 kPa, this trapping agent can capture CO2 concentrations of less than 5% in the air. After being refrigerated at -15°C for 120 days, it maintains high low-temperature stability without stratification, turbidity, or crystallization.

[0036] The mechanism and chemical equations for the reaction of some of the formulation components with CO2 are as follows:

[0037] ① The chemical equation for the reaction between N-methyldiethanolamine (45% MDEA) and carbon dioxide is as follows:

[0038]

[0039]

[0040]

[0041] ② Tetraethylenepentamine (TEPA) can undergo various reactions with carbon dioxide:

[0042]

[0043]

[0044] ③ Monoethanolamine (MEA) can react with carbon dioxide in the following way:

[0045]

[0046] ④ Methanol and carbon dioxide can undergo the following reaction:

[0047]

[0048] ⑤ Polyethyleneimine (PEI) molecules contain abundant primary, secondary, and tertiary amines. The adsorption reaction with CO2 begins with the lone pair of electrons on the primary or secondary amine attacking the positively charged carbon atom on the CO2 atom, forming an amphoteric particle. This particle then interacts with another non-tertiary amine, a water molecule, or other hydroxide ions to form a metastable urethane structure. Figure 1 The adsorption reaction equations for primary or secondary amines are as follows:

[0049] CO2 + RNH2 → RNH2 - CO2;

[0050] RNH2-CO2+B→RNHCOO - +BH + ;

[0051] In the above formula, B represents another non-tertiary amine group, a water molecule, or a hydroxide ion. The tertiary amine captures CO2 by promoting the reaction between CO2 molecules and water molecules to form bicarbonate, as shown in the following reaction equation:

[0052] R3N + H2O + CO2 → R3NH + +HCO3 - ;

[0053] ⑥ Piperazine at 5% concentration can react with carbon dioxide in the following way:

[0054]

[0055]

[0056] Example 1:

[0057] Example 1 of this invention discloses a carbon dioxide trapping agent, the formulation of which includes: 15 mL of diethanolamine, 20 mL of triethylenetetramine, 80 mL of tetraethylenepentamine, 15 mL of ethanolamine, 20 mL of triethanolamine, 50 mL of methanol, 10 mL of polyethyleneimine, 12 g of piperazine, and 10 mL of initiator.

[0058] Example 1 of this invention also discloses a method for preparing a carbon dioxide trap, comprising the following steps:

[0059] Add 50 mL of methanol and 12 g of piperazine to the reaction vessel and stir. After the piperazine is completely dissolved, add 15 mL of ethanolamine, 15 mL of diethanolamine, 20 mL of triethylenetetramine, 80 mL of tetraethylenepentamine and 20 mL of triethanolamine to the reaction vessel in sequence. After each reagent is added, stir at 50 r / min for 5 min. Then add 10 mL of polyethyleneimine and 10 mL of the initiator N-methyldiethanolamine. When the solution becomes a completely homogeneous and transparent solution, stop stirring and cool to room temperature to obtain the target product.

[0060] Example 2:

[0061] Example 2 of the present invention discloses a carbon dioxide trapping agent, the formulation of which includes: 10 mL of diethanolamine, 15 mL of triethylenetetramine, 40 mL of tetraethylenepentamine, 8 mL of ethanolamine, 10 mL of triethanolamine, 20 mL of methanol, 5 mL of polyethyleneimine, 6 g of piperazine, and 8 mL of initiator.

[0062] Example 2 of this invention also discloses a method for preparing a carbon dioxide trap, comprising the following steps:

[0063] Add 20 mL of methanol and 6 g of piperazine to the reaction vessel and stir. After the piperazine is completely dissolved, add 8 mL of ethanolamine, 10 mL of diethanolamine, 15 mL of triethylenetetramine, 40 mL of tetraethylenepentamine and 10 mL of triethanolamine to the reaction vessel in sequence. After each reagent is added, stir at 50 r / min for 5 min. Then add 5 mL of polyethyleneimine and 8 mL of the initiator N-methyldiethanolamine. When the solution becomes a completely homogeneous and transparent solution, stop stirring and cool to room temperature to obtain the target product.

[0064] Example 3:

[0065] Example 3 of the present invention discloses a carbon dioxide trapping agent, the formulation of which includes: 8 mL of diethanolamine, 15 mL of triethylenetetramine, 50 mL of tetraethylenepentamine, 6 mL of ethanolamine, 5 mL of triethanolamine, 30 mL of methanol, 2 mL of polyethyleneimine, 5 g of piperazine, and 5 mL of initiator.

[0066] Example 3 of this invention also discloses a method for preparing a carbon dioxide trap, comprising the following steps:

[0067] Add 30 mL of methanol and 5 g of piperazine to the reaction vessel and stir. After the piperazine is completely dissolved, add 6 mL of ethanolamine, 8 mL of diethanolamine, 15 mL of triethylenetetramine, 50 mL of tetraethylenepentamine and 5 mL of triethanolamine to the reaction vessel and stir at 50 r / min for 5 min. Then add 2 mL of polyethyleneimine and 5 mL of initiator N-methyldiethanolamine. When the solution becomes a homogeneous and transparent solution, stop stirring and cool to room temperature to obtain the target product.

[0068] Example 4:

[0069] Example 4 of the present invention discloses a carbon dioxide trapping agent, the formulation of which includes: 15 mL of diethanolamine, 10 mL of triethylenetetramine, 30 mL of tetraethylenepentamine, 10 mL of ethanolamine, 15 mL of triethanolamine, 20 mL of methanol, 2 mL of polyethyleneimine, 8 g of piperazine, and 10 mL of initiator.

[0070] Example 4 of this invention also discloses a method for preparing a carbon dioxide trap, comprising the following steps:

[0071] Add 20 mL of methanol and 8 g of piperazine to the reaction vessel and stir. After the piperazine is completely dissolved, add 10 mL of ethanolamine, 15 mL of diethanolamine, 10 mL of triethylenetetramine, 30 mL of tetraethylenepentamine and 15 mL of triethanolamine to the reaction vessel. After each reagent is added, stir at 50 r / min for 5 min. Then add 2 mL of polyethyleneimine and 10 mL of the initiator N-methyldiethanolamine. When the solution becomes a completely homogeneous and transparent solution, stop stirring and cool to room temperature to obtain the target product.

[0072] Test example:

[0073] This invention aims to develop a high-efficiency and low-cost CO2 trapping agent for CCUS. Therefore, its main technical indicators are four items: CO2 saturated absorption capacity, saturated absorbent viscosity, CO2 desorption rate, and CO2 reabsorption capacity.

[0074] 1. The test method for CO2 saturation absorption capacity is to test the absorption efficiency of the sample for carbon dioxide on a stainless steel carbon dioxide absorption device conventionally used in this field. First, prepare the required test solution and fill it into the carbon dioxide absorption bottle, such as... Figure 2 As shown. Then, its initial weight is recorded as m1. Then, a certain amount of CO2 gas is introduced through the long tube. After 20 minutes, the gas introduction is stopped, and the mass of the gas washing bottle after absorbing CO2 is measured and recorded as m2. The formula for calculating the saturated absorption is as follows.

[0075]

[0076] 2. The viscosity of the saturated absorbent was tested using a viscosity tester that complies with national standards.

[0077] 3. The CO2 desorption rate was determined using vacuum evaporation. First, the mass m2 of the absorbent after saturation CO2 adsorption was measured. Then, the saturated CO2-adsorbed liquid was placed in a vacuum evaporation oven. The test pressure was adjusted to -1 atm, and the temperature was raised to 85℃. The gas was then collected at the instrument outlet and analyzed by gas chromatography. The desorption was considered complete when the CO2 concentration remained unchanged after three gas chromatography tests. The mass m3 of the desorbed absorbent was then measured. The formula for calculating the desorption rate is as follows.

[0078]

[0079] 4. The test method for CO2 repetitive absorption is the same as the test method for absorption rate.

[0080] The sample numbers corresponding to Examples 1 to 5 above are recorded as 1#, 2#, 3#, and 4#, respectively. The test results of Examples 1 to 4 are shown in Table 1 below.

[0081] Table 1. Test results of various technical indicators in Examples 1-4

[0082]

[0083] The performance indicators of internationally renowned amine liquid brands and domestically renowned amine liquid brands were compared, and the corresponding test results and reports were issued by authoritative testing institutions. The specific results are shown in Table 2 below.

[0084] Table 2 Comparison of Amine Liquid Performance Test Data

[0085]

[0086]

[0087] The experimental results show that the amine liquid independently synthesized and developed in Example 4 of this invention is far superior to other products in terms of four indicators: CO2 saturated absorption capacity, saturated absorbent viscosity, CO2 desorption rate, and CO2 reabsorption capacity. Moreover, its market price is far lower than that of the other two types of amine liquids, giving it extremely high economic and market promotion value.

[0088] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A carbon dioxide trap, characterized in that, The carbon dioxide trap has the following composition: 2-15 mL diethanolamine, 6-20 mL triethylenetetramine, 20-80 mL tetraethylenepentamine, 2-15 mL ethanolamine, 5-20 mL triethanolamine, 10-50 mL methanol, 1-10 mL polyethyleneimine, 1-12 g piperazine, and 2-10 mL N-methyldiethanolamine. The preparation method of the carbon dioxide trap includes the following steps: Add methanol and piperazine to the reaction vessel and stir at room temperature. After the piperazine is completely dissolved, add ethanolamine, diethanolamine, triethylenetetramine, tetraethylenepentamine and triethanolamine in sequence to the reaction vessel. Stir for 5 min to 10 min after each reagent is added before adding the next one. Then add polyethyleneimine and N-methyldiethanolamine. When the solution becomes a completely homogeneous and transparent solution, stop stirring and cool to room temperature to obtain the target product.

2. The carbon dioxide trap according to claim 1, characterized in that, The carbon dioxide trap has the following composition: 8-15 mL diethanolamine, 10-20 mL triethylenetetramine, 30-80 mL tetraethylenepentamine, 6-15 mL ethanolamine, 5-20 mL triethanolamine, 20-50 mL methanol, 2-10 mL polyethyleneimine, 5-12 g piperazine, and 5-10 mL N-methyldiethanolamine.

3. A method for preparing a carbon dioxide trap as described in any one of claims 1-2, characterized in that, The method includes the following steps: Add methanol and piperazine to the reaction vessel and stir at room temperature. After the piperazine is completely dissolved, add ethanolamine, diethanolamine, triethylenetetramine, tetraethylenepentamine and triethanolamine in sequence to the reaction vessel. Stir for 5 min to 10 min after each reagent is added before adding the next one. Then add polyethyleneimine and N-methyldiethanolamine. When the solution becomes a completely homogeneous and transparent solution, stop stirring and cool to room temperature to obtain the target product.

4. The method for preparing a carbon dioxide trap according to claim 3, characterized in that, The stirring conditions after adding each agent include: a stirring speed of 50 r / min to 60 r / min and a stirring time of 5 min to 10 min.

5. The application of a carbon dioxide trap as described in any one of claims 1-2, characterized in that, The maximum saturated CO2 absorption capacity of the carbon dioxide capture agent is 95.1 mg / g, which is 8 to 9 times that of monoethanolamine under the same conditions; the maximum repeatable absorption capacity is 91.4%, and the maximum resolution rate is 98%.

6. The application of the carbon dioxide trap according to claim 5, characterized in that, When used at a temperature of -15 ℃ to 30 ℃ and a pressure of 101 kPa, the carbon dioxide capture agent can capture CO2 with a concentration of less than 5% in the air. After being refrigerated at -15 ℃ and left to stand for 120 days, it shows no stratification, turbidity, or crystallization.

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