Method for capturing carbon dioxide and carbon dioxide capture system

Abstract

The present invention relates to a method for capturing carbon dioxide and a carbon dioxide capture system capable of implementing same. More particularly, the present invention relates to a method and a system for maximizing carbon dioxide absorption performance by combining a K / MgO catalyst synthesized at the nanoscale with an amine-based absorbent such as monoethanolamine (MEA). The present invention provides a technology for improving carbon dioxide absorption process efficiency and reducing energy consumption by optimizing a synthesis method of a K / MgO catalyst for capturing carbon dioxide, carbon dioxide absorption reaction conditions, and absorption tower structure.

Description

Carbon dioxide capture method and carbon dioxide capture system

[0001] The present invention relates to a method for capturing carbon dioxide and a carbon dioxide capture system capable of implementing the same. More specifically, the present invention relates to a method and system for maximizing carbon dioxide absorption performance by combining a nano-sized synthesized K / MgO catalyst with an amine-based absorbent such as monoethanolamine (MEA). The present invention provides a technology that improves the efficiency of the carbon dioxide absorption process and reduces energy consumption by optimizing the synthesis method of the K / MgO catalyst for capturing carbon dioxide, the reaction conditions for carbon dioxide absorption, and the structure of the absorption tower.

[0002] Carbon dioxide capture technology is being widely studied as an important technology for mitigating climate change by reducing atmospheric carbon dioxide. For example, monoethanolamine (MEA) is a representative amine-based carbon dioxide absorbent that exhibits a rapid reaction rate and high absorption rate; however, when used alone, it has the problem of high energy consumption and limited absorption performance. To address this, carbon dioxide absorption technologies combined with solid catalysts are being researched, and among them, K / MgO catalysts demonstrate excellent performance in carbon dioxide absorption.

[0003] US Patent 12,098,112 B1 describes a technology for absorbing carbon dioxide using a red mud catalyst, but the surface area of ​​the catalyst is insufficient and it lacks an optimized structure.

[0004] [Prior Art Literature]

[0005] [Patent Literature]

[0006] (Patent Document 1) U.S. Registered Patent No. 12,098,112 (Registered Sep. 24, 2024)

[0007] In existing carbon dioxide absorption processes, amine-based absorbents such as MEA have limited absorption performance and, in particular, consume a large amount of energy during the regeneration process. Even in studies introducing solid catalysts, carbon dioxide absorption performance could not be maximized due to insufficient surface area or low reactivity.

[0008] The objective of the present invention is to solve these problems and improve carbon dioxide absorption performance by synthesizing a K / MgO catalyst in nanoscale. Furthermore, the invention focuses on improving process efficiency and reducing energy consumption by optimizing the absorption tower structure.

[0009] The present invention provides a technology that improves carbon dioxide absorption performance by expanding the surface area through the synthesis of a K / MgO catalyst to a nano size (e.g., 10 to 50 nm) and increases the absorption rate through combination with an MEA. The present invention presents optimized synthesis and reaction conditions to maximize the performance of the K / MgO catalyst in a carbon dioxide capture process.

[0010] The objectives of the present invention are not limited to those mentioned above, and other objectives and advantages of the present invention not mentioned may be understood from the following description and will be more clearly understood by the embodiments of the present invention. Furthermore, it will be readily apparent that the objectives and advantages of the present invention can be realized by the means and combinations thereof set forth in the claims.

[0011] To achieve the above objective, a carbon dioxide capture method according to one embodiment of the present invention may include the following steps:

[0012] (S1) A step of providing a nano-sized K / MgO catalyst;

[0013] (S2) A step of mixing and introducing the nano-sized K / MgO catalyst and amine-based absorbent into an absorption tower; and

[0014] (S3) A step of introducing a gas containing carbon dioxide into an absorption tower to absorb carbon dioxide.

[0015] The average particle size of the above nano-sized K / MgO catalyst may be 10 nm to 50 nm.

[0016] The above amine-based absorbent may include monoethanolamine (MEA).

[0017] In the above (S2) step, the mixing ratio of the K / MgO catalyst and the amine-based absorbent may be 80:20 to 20:80 (weight ratio).

[0018] The above step (S3) can be performed under temperature conditions of 30°C to 60°C.

[0019] The above-mentioned gas containing carbon dioxide may further contain air.

[0020] Carbon dioxide may be included in an amount of 5 to 15 vol% relative to the total volume of the gas containing carbon dioxide.

[0021] A carbon dioxide capture method according to another aspect of the present invention may further include the following steps:

[0022] (S4) A step of removing impurities and organic acid substances generated in the above (S3) step using an impurity removal filter.

[0023] The above-mentioned filter for removing impurities may include one or more of a non-woven fabric filter and an activated carbon filter.

[0024] The above activated carbon filter can be manufactured from one or more raw materials selected from the group consisting of coconut, coal, and brown coal.

[0025] The average particle size of the above activated carbon filter may be 0.60 mm to 4.75 mm.

[0026] The above impurities may include one or more of amine-based impurities and ammonium-based impurities.

[0027] The above organic acid substances may include one or more of acetic acid and formic acid.

[0028] A method for capturing carbon dioxide according to another aspect of the present invention may include the following steps in step (S1):

[0029] (S1-1) A step of preparing MgO particles having an average particle size of 10 to 50 nm;

[0030] (S1-2) A step of impregnating the MgO particles in a potassium nitrate solution; and

[0031] (S1-3) A step of heat-treating the above-mentioned impregnated MgO particles at a temperature of 450 to 550°C to bond potassium (K) to the surface of MgO, thereby obtaining a K / MgO catalyst.

[0032] The above (S1-1) step can be performed using an ultrasonic grinding method.

[0033] According to another aspect of the present invention, a carbon dioxide capture system may be provided, comprising: an absorption tower comprising a packing configured in the form of structured packing or random packing, a nano-sized K / MgO catalyst having an average particle size of 10 nm to 50 nm and an amine-based absorbent, wherein a gas containing carbon dioxide is supplied to a bottom inlet to absorb carbon dioxide; and an impurity removal filter for removing impurities and organic acid substances generated as the amine-based absorbent reacts with carbon dioxide.

[0034] The above absorption tower may be composed of alternating packings in the form of structured packing or random packing and inert marble ceramic supports containing AlO2 or SiO2.

[0035] The above nano-sized K / MgO catalyst and amine-based absorbent may be included in the ceramic support.

[0036] The type, raw material, and average particle size of the filter for removing impurities described above are as described above in one embodiment of the present invention.

[0037] The above carbon dioxide capture system may further include a heat exchanger and a stripping tower.

[0038] The present invention can significantly improve carbon dioxide absorption performance by synthesizing a K / MgO catalyst to a size of 10-50 nm to expand its surface area. The K / MgO catalyst of the present invention can improve reactivity with carbon dioxide through the expanded surface area, and the absorption rate and efficiency can be maximized through combination with an MEA absorbent. Through the combination of the K / MgO catalyst and the MEA absorbent, the present invention can improve the carbon dioxide absorption rate by more than 30% compared to the use of the MEA absorbent alone, reduce energy consumption in the carbon dioxide absorption process, and maximize process efficiency through the optimization of the absorption tower structure. The absorption tower structure increases absorption efficiency by increasing the contact time between the K / MgO catalyst and carbon dioxide.

[0039] In addition to the effects described above, the effects of the present invention are described together with the details for implementing the invention below.

[0040] FIG. 1 briefly illustrates a flowchart of a carbon dioxide capture method according to one embodiment of the present invention.

[0041] FIG. 2 briefly illustrates a flowchart of a carbon dioxide capture method according to another embodiment of the present invention.

[0042] FIG. 3 is a plan view showing the structure of a carbon dioxide absorption tower using a K / MgO catalyst and an MEA absorbent according to one embodiment of the present invention.

[0043] Figure 4 is a simulation result showing the interaction between the nanostructure of a K / MgO catalyst according to one embodiment of the present invention and carbon dioxide and MEA.

[0044] The aforementioned objectives, features, and advantages are described in detail below with reference to the description of the invention and the drawings, and accordingly, a person skilled in the art to which the present invention pertains will be able to easily implement the technical concept of the present invention. In describing the present invention, detailed descriptions of known technologies related to the present invention are omitted if it is determined that such descriptions may unnecessarily obscure the essence of the present invention. Hereinafter, preferred embodiments according to the present invention will be described in detail.

[0045] Where terms such as "comprising," "having," "consisting of," "arranging," or "having" are used for a component in this specification, other parts may be added unless "only" is used. Where a component is expressed in the singular, it includes cases where it is included in the plural unless specifically stated otherwise.

[0046] In interpreting the components in this specification, they are interpreted to include an error range even if there is no separate explicit description.

[0047] The present invention will be described in more detail below.

[0048] carbon dioxide capture method

[0049] A carbon dioxide capture method according to the present invention may include: (S1) a step of providing a nano-sized K / MgO catalyst; (S2) a step of mixing and introducing the nano-sized K / MgO catalyst and an amine-based absorbent into an absorption tower; and (S3) a step of introducing a gas containing carbon dioxide into the absorption tower to absorb carbon dioxide.

[0050] The absorption tower of step (S2) above may be composed of a column, for example, a cylindrical column. The interior of the column may be configured in the form of structured packing or random packing. The K / MgO catalyst and the amine-based absorbent may be supported on the surface of the packing and used in the reaction.

[0051] The gas containing carbon dioxide from step (S3) above can be supplied to the bottom inlet of the absorption tower as shown in Fig. 3.

[0052] The above step (S3) can be performed at a temperature of 30°C to 60°C, for example, 30°C to 50°C. The above reaction temperature is the optimal temperature at which the catalyst exhibits activity, and if the reaction temperature is higher than 60°C, there may be problems such as insufficient carbon dioxide absorption rate (i.e., reaction efficiency) or reduced process efficiency. If the reaction temperature is lowered to below 30°C, the viscosity of the absorption solution in the absorption tower increases, which may cause problems such as difficulty in circulating the solution.

[0053] The carbon dioxide-containing gas in step (S3) above may further include air. Carbon dioxide may be included in an amount of 5 to 15 vol% relative to the total volume of the carbon dioxide-containing gas. If the concentration of carbon dioxide is lowered to less than 5 vol%, a problem may arise in which the absorption time of carbon dioxide increases proportionally. If the concentration of carbon dioxide is higher than 15 vol%, the absorbent in the absorption tower becomes saturated too quickly, reducing the absorption efficiency, and thus carbon dioxide may not be sufficiently absorbed thereafter, leading to a problem in which the concentration of carbon dioxide in the off-gas increases.

[0054] The inflow rate of the gas containing carbon dioxide in step (S3) above may be 0.8 to 1.2 L / min. If the inflow rate of the gas is outside this range, the volume ratio of the gas to the liquid in the absorption tower will be outside the desirable range of 4.0 to 10.0, which may lead to problems such as flooding of the absorption tower and reduced reaction efficiency.

[0055] The nano-sized K / MgO catalyst of step (S1) above can be prepared by a method comprising: (S1-1) a step of preparing MgO particles having an average particle size of 10 to 50 nm; (S1-2) a step of impregnating the MgO particles in a potassium nitrate solution; and (S1-3) a step of heat-treating the impregnated MgO particles at a temperature of 450 to 550°C to bind potassium (K) to the surface of MgO, thereby obtaining a K / MgO catalyst.

[0056] The above step (S1-1) can be performed using an ultrasonic grinding method. The MgO powder used for grinding is not particularly limited, and commercially available powder can be used. The MgO powder can be ground to a size of 10 to 50 nm due to high-energy treatment, and the surface area can be expanded accordingly.

[0057] The ultrasonic grinding in step (S1-1) above can be performed at a speed of 500 to 700 rpm. If the ultrasonic grinding speed is less than 500 rpm, the ultrasonic energy is not sufficiently transmitted, so the MgO particles may not be sufficiently ground, and as a result, the average particle size of the MgO particles may exceed 50 nm. In addition, there may be a problem in that the standard deviation of the MgO particle size increases because the ultrasonic energy is not transmitted evenly, making it difficult to produce uniform MgO particles. If the ultrasonic grinding speed exceeds 700 rpm, the ultrasonic energy is excessively transmitted, so the MgO particles may be ground too finely, and as a result, the average particle size of the MgO particles may become less than 10 nm. In addition, the MgO particles may be damaged or aggregated due to excessive energy, which increases the standard deviation of the MgO particle size and may have a negative effect on the production of uniform MgO particles.

[0058] The ultrasonic grinding of step (S1-1) above can be performed for 20 to 28 hours. If the grinding time is outside this range, the average particle size of the MgO particles may deviate from 10-50 nm, and the standard deviation of the particle size may increase, making it difficult to produce uniform MgO particles.

[0059] In step (S1-2) above, a potassium nitrate solution may be used to impregnate the MgO particles with potassium (K). Since potassium nitrate dissolves better in an aqueous solution compared to potassium carbonate, it may be advantageous for evenly impregnating the surface of the MgO particles with potassium.

[0060] In the above step (S1-2), the concentration of the potassium nitrate solution may be 0.8 M to 1.2 M. If the concentration of the potassium nitrate solution is less than 0.8 M, potassium may not be sufficiently impregnated into the MgO particles, which may result in insufficient formation of active sites of the K / MgO catalyst and a decrease in carbon dioxide absorption performance. Additionally, potassium ions may not be evenly distributed on the surface of the MgO particles, which may impair the uniformity of the K / MgO catalyst. If the concentration of the potassium nitrate solution is greater than 1.2 M, excessive potassium may be impregnated into the MgO particles, which may cause potassium ions to accumulate excessively on the surface of the MgO particles and induce aggregation between particles. Furthermore, excessive potassium impregnation reduces the surface area of ​​the MgO particles, which may lower the carbon dioxide absorption performance of the K / MgO catalyst.

[0061] In the above step (S1-2), the MgO particles may be impregnated for 11 to 13 hours. If the impregnation time is less than 11 hours, potassium may not be sufficiently impregnated into the MgO particles, which may result in insufficient formation of active sites of the K / MgO catalyst and a decrease in carbon dioxide absorption performance. Additionally, potassium ions may not be evenly distributed on the surface of the MgO particles, which may impair the uniformity of the catalyst. If the impregnation time exceeds 13 hours, excessive potassium may be impregnated into the MgO particles, which may cause potassium ions to accumulate excessively on the surface of the MgO particles and induce aggregation between particles. Furthermore, excessive potassium impregnation reduces the surface area of ​​the MgO particles, which may lower the carbon dioxide absorption performance of the K / MgO catalyst.

[0062] Potassium can be evenly distributed on the surface of the MgO particles by the above (S1-2) step, and active sites of the K / MgO catalyst can be formed.

[0063] The MgO particles impregnated in step (S1-3) above can be heat-treated at a temperature of 450 to 550°C. If the temperature is outside this range, there may be a problem where potassium is sintered too weakly or grows too much at the interface of the impregnated MgO particles.

[0064] In the above (S1-3) step, the heat treatment can be performed for 5 to 6 hours. Through the heat treatment process, K is chemically bonded to the surface of MgO and stabilized, and the carbon dioxide absorption performance of the K / MgO catalyst can be maximized. If the heat treatment time is outside the above range, there may be a problem where potassium is sintered too weakly or grows too excessively at the interface of the impregnated MgO particles.

[0065] A carbon dioxide capture method according to another embodiment of the present invention (S4) may further include a step of removing impurities and organic acid substances generated in step (S3) using an impurity removal filter. The carbon dioxide absorption reaction can be further improved by step (S4).

[0066] The above-mentioned filter for removing impurities may include one or more of a non-woven fabric filter and an activated carbon filter. The above-mentioned activated carbon filter may be manufactured from one or more raw materials selected from the group consisting of coconut, coal, and brown coal. The average particle size of the above-mentioned activated carbon filter may be 0.60 mm to 4.75 mm.

[0067] The above impurities may include one or more of amine-based impurities and ammonium-based impurities. The above organic acid substances may include one or more of acetic acid and formic acid.

[0068] carbon dioxide capture system

[0069] The carbon dioxide capture system according to the present invention may include a nano-sized K / MgO catalyst and an amine-based absorbent. The K / MgO catalyst can be combined with an amine-based absorbent to improve the carbon dioxide absorption rate.

[0070] The above K / MgO catalyst may have an average particle size of 10 to 50 nm. By synthesizing the above K / MgO catalyst into a nano-size, the surface area is expanded, which can improve carbon dioxide absorption performance. If the average particle size of the above K / MgO catalyst becomes larger than 50 nm, there may be a problem where the surface area of ​​the K / MgO catalyst decreases, leading to a decrease in reactivity. If the average particle size of the above K / MgO catalyst becomes smaller than 10 nm, there may be a problem where the thermal stability of the K / MgO catalyst decreases, leading to a decrease in reactivity.

[0071] The above amine-based absorbent may include one or more selected from commonly used amine-based absorbents such as monoethanolamine (MEA), diethanolamine (DEA), triethanolamine (TEA), and methyldiethanolamine (MDEA). The above amine-based absorbent may preferably be monoethanolamine. The above K / MgO catalyst may be combined with monoethanolamine to maximize the carbon dioxide absorption performance.

[0072] The above amine-based absorbent may include water as a solvent. When the total weight of the amine-based absorbent and water is 100% by weight, the amine-based absorbent may be included in an amount of 30% by weight or more, for example, 50% by weight or less. If the amine-based absorbent is less than 30% by weight, the reaction with carbon dioxide may not occur sufficiently, which may reduce the overall absorption performance. If the amine-based absorbent exceeds 50% by weight, the efficiency of carbon dioxide absorption may decrease, and there may be problems with reduced stability and safety.

[0073] The mixing ratio of the K / MgO catalyst and the amine-based absorbent may be 80:20 to 20:80 (weight ratio). If the ratio of the K / MgO catalyst exceeds 80 weight%, the reaction with carbon dioxide may not occur sufficiently, which may reduce the overall absorption performance. Additionally, the efficiency of the catalyst may decrease because the amine-based absorbent does not react sufficiently. If the ratio of the K / MgO catalyst is less than 20 weight%, the role of the K / MgO catalyst in promoting the carbon dioxide absorption reaction may not be sufficiently performed, which may reduce the absorption rate and efficiency. Furthermore, energy consumption may increase during the regeneration process of the amine-based absorbent, which may reduce the efficiency of the entire process.

[0074] The composition of the above K / MgO catalyst can be set to K: 5-10 wt.% and MgO: 90-95 wt.%. By setting the K / MgO catalyst to the above composition, the reactivity with carbon dioxide is improved. If the weight ratio range is exceeded, potassium may not be sufficiently impregnated into the MgO particles, resulting in a lack of active sites for the K / MgO catalyst, or potassium may be excessively impregnated into the active sites, which may degrade performance.

[0075] The above K / MgO catalyst and amine-based absorbent may be reusable. After being used for the absorption of carbon dioxide, the amine-based absorbent may be transferred to a stripping tower and regenerated by heat treatment, for example, at 90 to 110°C to desorb carbon dioxide. The heat treatment may be performed, for example, for 1 to 3 hours. The above K / MgO catalyst and amine-based absorbent may maintain at least 95% of their absorption performance even after regeneration.

[0076] A carbon dioxide capture system according to the present invention may include an absorption tower. The absorption tower may include a K / MgO catalyst and an amine-based absorbent. For example, referring to FIG. 3, the interior of the absorption tower may alternately consist of a portion configured in the form of structured packing or random packing and an inert marble ceramic support comprising AlO2 or SiO2. The K / MgO catalyst and the amine-based absorbent may be included in the ceramic support portion.

[0077] The carbon dioxide capture system according to the present invention may further include an impurity removal filter. The impurity removal filter can remove impurities and / or organic acid substances generated as an amine-based absorbent reacts with carbon dioxide.

[0078] The above impurities may include one or more of amine-based impurities and ammonium-based impurities. The amine-based impurities may include one or more of 2-aminoethanol, diethanolamine, triethylamine, methyldiethanolamine, imidazole, and piperazine, but are not limited thereto. The ammonium-based impurities may include NH4OH, etc., but are not limited thereto.

[0079] The above organic acid substances may include one or more of acetic acid, oxalic acid, and formic acid.

[0080] The above-mentioned filter for removing impurities may include one or more of a physical filter and an activated carbon filter. The above-mentioned physical filter may be a non-woven fabric filter.

[0081] The above activated carbon filter may be manufactured from one or more raw materials selected from the group consisting of coconut, coal, and brown coal. The average particle size of the above activated carbon filter may be 0.60 mm to 4.75 mm. If the average particle size falls outside this range, the removal of impurities may not be smooth, which may lead to a decrease in overall absorption performance and problems such as increased operating costs due to the additional supply of absorbent material.

[0082] The carbon dioxide capture system according to the present invention may further include a heat exchanger and a stripping tower. The heat exchanger may reduce the thermal energy supplied from the reboiler of the stripping tower by exchanging the temperature between the absorption tower and the stripping tower. The stripping tower may apply heat to the amine-CO2-H2O system formed in the absorption tower to break the bond between amine and CO2. The amine-based absorbent regenerated after the stripping tower reaction may be transported back to the absorption tower and reused.

[0083] Hereinafter, the present invention will be described in detail with reference to examples to specifically explain the invention. However, the embodiments according to the present invention may be modified in various different forms, and the scope of the present invention is not to be interpreted as being limited to the embodiments described below. The embodiments of this specification are provided to more completely explain the present invention to those with average knowledge in the art.

[0084] <Examples and Comparative Examples>

[0085] Synthesis Example 1. Method of synthesizing a catalyst

[0086] 1-1. Preparation of MgO Nanoparticles

[0087] To increase the surface area of ​​MgO particles, MgO powder was treated with high energy using an ultrasonic grinder. 30 g of MgO powder was ultrasonically ground at a speed of 600 rpm for 24 hours. Through this process, the MgO powder was ground into MgO particles having an average particle size of 10 nm.

[0088] 1-2. Potassium Nitrate (KNO3) Impregnation

[0089] To impregnate the 30g MgO particles prepared in 1-1 above with potassium, 300 mL of a 0.1 M potassium nitrate (KNO3) solution was used and impregnated at room temperature for 12 hours.

[0090] 1-3. Heat Treatment

[0091] Potassium-impregnated MgO particles were heat-treated at 500°C for 5 hours to complete the K / MgO catalyst.

[0092] Example 1. Simulation of interaction with carbon dioxide

[0093] The structure combining the K / MgO catalyst and MEA, the interaction with carbon dioxide, and the interaction between MEA and carbon dioxide were verified by simulation using CASTEP in Materials Studio. The results are shown in Figure 4.

[0094] It was confirmed that the carbon dioxide capture system of the present invention has better binding power with carbon dioxide than the use of the MEA absorbent alone, as the binding energy when carbon dioxide is absorbed in a structure where MEA is combined with a K / MgO catalyst is lower than the binding energy when carbon dioxide is combined with MEA alone.

[0095] Example 2. Carbon Dioxide Absorption Performance Test

[0096] Experimental Example 1. Combination of K / MgO catalyst and MEA

[0097] A carbon dioxide absorption test was conducted using a gas absorption device. A composition consisting of 30 wt.% MEA and 70 wt.% water, with the total weight of MEA and water being 100 wt.%, was fed into the absorption tower at a rate of 0.6 L / min. After feeding in 160 g of the K / MgO catalyst (average particle size 10 nm) prepared in Synthesis Example 1, a 10 vol% carbon dioxide / air mixed gas was introduced at a flow rate of 1 L / min. The reaction temperature was maintained at 40°C, and the absorption time was set to 60 minutes. The absorption performance was evaluated by monitoring changes in carbon dioxide concentration during the experiment.

[0098] Comparative Experiment Example 1: Use of MEA alone

[0099] The carbon dioxide absorption performance was measured in the same manner as in Experimental Example 1, except that a composition consisting of 30 wt.% MEA and 70 wt.% water was fed into the absorption tower at a rate of 0.6 L / min, with the total weight of MEA and water being 100 wt.%.

[0100] The results of Experimental Example 1 and Comparative Experimental Example 1 are shown in Table 1 below.

[0101] Comparison of Carbon Dioxide Concentration in Supply Gas (Volume %) and Carbon Dioxide Concentration in Offgas (Volume %) Experimental Example 1: MEA 10.2 3.55 Experimental Example 1: MEA + K / MgO Catalyst 10.3 0.52

[0102] Experimental results confirmed that the process of the present invention, which combines a K / MgO catalyst and an MEA, rapidly improves the absorption rate compared to the process using MEA alone. Experimental Example 1 of the present invention showed a result in which the carbon dioxide concentration decreased rapidly, achieving an absorption rate of over 95% within 20 minutes. As shown in Table 1 above, it was confirmed that the process combining a K / MgO catalyst and an MEA exhibits approximately 30% higher carbon dioxide absorption performance compared to the conventional process using MEA alone.

[0103] Example 3. K / MgO Catalyst Regeneration Test

[0104] The reusability of the K / MgO catalyst was evaluated after desorbing carbon dioxide by treating the K / MgO catalyst and MEA absorbent that had absorbed carbon dioxide at 100°C for 2 hours. It was found that the catalyst maintained more than 95% of its absorption performance even after regeneration, confirming that the performance of the K / MgO catalyst did not deteriorate after regeneration.

[0105] As seen in the above examples, the present invention has confirmed that the carbon dioxide absorption performance can be maximized by synthesizing a K / MgO catalyst in nano-size (average particle size 10-50 nm) and combining it with an amine-based absorbent, MEA, and that it can be reused.

[0106] Although an embodiment of the present invention has been described above, those skilled in the art may modify and change the present invention in various ways by adding, changing, deleting, or adding components, etc., without departing from the spirit of the present invention as described in the claims, and such modifications and changes are also to be included within the scope of the rights of the present invention.

Claims

1. (S1) A step of providing a nano-sized K / MgO catalyst; (S2) A step of mixing and introducing the nano-sized K / MgO catalyst and amine-based absorbent into an absorption tower; and (S3) A step of introducing a gas containing carbon dioxide into an absorption tower to absorb carbon dioxide; comprising, Carbon dioxide capture method.

2. In Paragraph 1, A method for capturing carbon dioxide satisfying the condition that the average particle size of the nano-sized K / MgO catalyst is 10 nm to 50 nm.

3. In Paragraph 1, A method for capturing carbon dioxide, comprising one or more amine-based absorbents selected from the group consisting of monoethanolamine (MEA), diethanolamine (DEA), triethanolamine (TEA), and methyldiethanolamine (MDEA).

4. In Paragraph 1, A method for capturing carbon dioxide, wherein the above-mentioned amine-based absorbent comprises monoethanolamine (MEA).

5. In Paragraph 1, A method for capturing carbon dioxide, wherein in step (S2) above, the mixing ratio of the K / MgO catalyst and the amine-based absorbent is 80:20 to 20:80 (weight ratio).

6. In Paragraph 1, The above (S3) step is a method for capturing carbon dioxide, performed under temperature conditions of 30°C to 60°C.

7. In Paragraph 1, A method for capturing carbon dioxide, wherein the gas containing the above carbon dioxide further includes air.

8. In Paragraph 1, A method for capturing carbon dioxide, wherein the carbon dioxide is included in an amount of 5 to 15 vol% relative to the total volume of the gas containing the carbon dioxide.

9. In Paragraph 1, (S4) A method for capturing carbon dioxide, further comprising the step of removing impurities and organic acid substances generated in step (S3) using an impurity removal filter.

10. In Paragraph 9, The above impurities include one or more of amine-based impurities and ammonium-based impurities, and A method for capturing carbon dioxide, wherein the above organic acid substances include one or more of acetic acid and formic acid.

11. In Paragraph 1, The above (S1) step is, (S1-1) A step of preparing MgO particles having an average particle size of 10 to 50 nm; (S1-2) A step of impregnating the MgO particles in a potassium nitrate solution; and (S1-3) A step of heat-treating the above-mentioned impregnated MgO particles at a temperature of 450 to 550°C to bind potassium (K) to the surface of MgO, thereby obtaining a K / MgO catalyst; comprising Carbon dioxide capture method.

12. In Paragraph 11, The above (S1-1) step is a carbon dioxide capture method performed by an ultrasonic grinding method.

13. An absorption tower comprising a packing configured in the form of structured packing or random packing, a nano-sized K / MgO catalyst having an average particle size of 10 nm to 50 nm and an amine-based absorbent, wherein a gas containing carbon dioxide is supplied to a bottom inlet to absorb carbon dioxide; and A filter for removing impurities and organic acid substances generated as an amine-based absorbent reacts with carbon dioxide, comprising Carbon dioxide capture system.

14. In Paragraph 13, The above absorption tower is composed of alternating packings formed in the form of structured packing or random packing and inert marble ceramic supports containing AlO2 or SiO2, Carbon dioxide capture system.

15. In Paragraph 14, The above-mentioned nano-sized K / MgO catalyst and amine-based absorbent are contained in the ceramic support, Carbon dioxide capture system.

16. In Paragraph 13, The above-mentioned filter for removing impurities comprises one or more of a non-woven fabric filter and an activated carbon filter, Carbon dioxide capture system.

17. In Paragraph 16, The above activated carbon filter is manufactured from one or more raw materials selected from the group consisting of coconut, coal, and brown coal. Carbon dioxide capture system.

18. In Paragraph 16, The average particle size of the above activated carbon filter is 0.60 mm to 4.75 mm, Carbon dioxide capture system.

19. In Paragraph 13, further including a heat exchanger and a stripping tower, Carbon dioxide capture system.

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