Mixed-amine carbon dioxide absorbent and method for capturing carbon dioxide using same

Abstract

The present invention relates to a mixed-amine carbon dioxide absorbent and a method for capturing carbon dioxide using same. The mixed-amine carbon dioxide absorbent according to the present invention has improved carbon dioxide absorption capacity and can be regenerated with low regeneration heat, thereby enabling high-efficiency, low-cost capture of carbon dioxide and regeneration of the absorbent.

Description

Mixed amine carbon dioxide absorbent and carbon dioxide capture method using the same

[0001] The present invention relates to a carbon dioxide absorbent and a method for capturing carbon dioxide using the same.

[0002] As greenhouse gases emitted from the use of fossil fuels cause global warming, the importance of Carbon Dioxide Capture and Storage (CCS) technology, which sequesters carbon dioxide—the main culprit of global warming—from the atmosphere, is receiving attention.

[0003] CCS technology can be classified into capture technology, which separates and recovers carbon dioxide generated from the use of fossil fuels; transport technology, which moves the captured carbon dioxide to storage sites; and storage technology, which injects the transported carbon dioxide into the ground or ocean to sequester and monitor it. Since carbon capture costs account for 75 to 85% of the total cost of CCS technology, low-cost capture processes are crucial for the commercialization of CCS technology.

[0004] Carbon dioxide capture technologies can be classified into pre-combustion, post-combustion, and oxy-fuel combustion depending on the capture method. Pre-combustion technology is a technology that separates high-concentration carbon dioxide and produces hydrogen in conjunction with IGCC power generation, and long-term utilization is required when considering the commercialization of power generation technology. On the other hand, post-combustion technology is a technology that can be applied in conjunction with pulverized coal-fired power generation, which is currently used in most power plants, and since short-term application is possible, demonstration research is currently being actively conducted worldwide. Post-combustion technology is a method that removes nitrogen oxides, dust, and sulfur oxides from combustion flue gas (carbon dioxide concentration of 3–15%) and captures and separates carbon dioxide using a separation device before releasing it into the atmosphere.

[0005] Currently, among commercially available carbon dioxide capture technologies, there is a technology that uses monoethanolamine (MEA) absorbent. Monoethanolamine has the property of absorbing acidic gases very well and releasing them again when heated, and typically, a 30 wt% aqueous solution of monoethanolamine is used. Processes using monoethanolamine absorbent solutions have the problem of consuming a large amount of energy to capture carbon dioxide. There is a need for a carbon dioxide absorbent with improved performance that can increase the amount and rate of carbon dioxide captured and reduce renewable energy consumption.

[0006] The present invention relates to a carbon dioxide absorbent and a method for capturing carbon dioxide using the same, and aims to provide a carbon dioxide absorbent with improved performance that can increase the amount and rate of carbon dioxide captured and reduce renewable energy consumption.

[0007] The present invention relates to a carbon dioxide absorbent and a method for capturing carbon dioxide using the same, and provides a mixed amine carbon dioxide absorbent comprising N-methyldiethanolamine (MDEA), diethylaminoethanol (DEEA), and piperazine (PZ), and a method for capturing carbon dioxide using the same.

[0008] The carbon dioxide absorbent according to the present invention has an enhanced carbon dioxide absorption capacity and can regenerate the absorbent with low regeneration heat, thereby enabling the capture of carbon dioxide and regeneration of the absorbent with high efficiency and low cost.

[0009] FIG. 1 is a schematic diagram showing a carbon dioxide capture system according to an embodiment of the present invention.

[0010] Figure 2 is a graph comparing the performance of carbon dioxide absorbent regenerative energy (specific reboiler duty, SRD) according to an embodiment of the present invention.

[0011] Figure 3 is a graph showing the carbon dioxide removal efficiency of a carbon dioxide absorbent at a reboiler temperature of 95°C according to an embodiment of the present invention.

[0012] Figure 4 is a graph comparing the performance of carbon dioxide absorbent regenerative energy (specific reboiler duty, SRD) at a reboiler temperature of 95°C according to an embodiment of the present invention.

[0013] Figure 5 is a graph showing the carbon dioxide removal efficiency of a carbon dioxide absorbent at a reboiler temperature of 100°C according to an embodiment of the present invention.

[0014] Figure 6 is a graph comparing the performance of carbon dioxide absorbent regenerative energy (specific reboiler duty, SRD) at a reboiler temperature of 100°C according to an embodiment of the present invention.

[0015] To achieve the above objective, a carbon dioxide absorbent is provided in one aspect of the present invention.

[0016] In one embodiment of the present invention, a mixed amine carbon dioxide absorbent comprising N-methyldiethanolamine (MDEA), diethylaminoethanol (DEEA), and piperazine (PZ) may be provided.

[0017] In one embodiment of the present invention, the piperazine may be included in a weight percent lower than that of N-methyldiethanolamine or diethylaminoethanol.

[0018] In one embodiment of the present invention, the N-methyldiethanolamine may be included in an amount of 10% to 50% by weight relative to the total weight of the carbon dioxide absorbent.

[0019] Carbon dioxide absorbent.

[0020] In one embodiment of the present invention, the diethylaminoethanol may be included in an amount of 5% to 30% by weight relative to the total weight of the carbon dioxide absorbent.

[0021] Carbon dioxide absorbent.

[0022] In one embodiment of the present invention, the piperazine may be included at a concentration of 0.5 m to 2.0 m relative to the total weight of the carbon dioxide absorbent.

[0023] In one embodiment of the present invention, the carbon dioxide absorbent may further include water.

[0024] In one embodiment of the present invention, the method may include the step of absorbing carbon dioxide from a gas mixture containing carbon dioxide using the carbon dioxide absorbent; and the step of regenerating the carbon dioxide absorbent by removing the carbon dioxide absorbed by the carbon dioxide absorbent.

[0025] In one embodiment of the present invention, the step of absorbing carbon dioxide may be performed in a temperature range of 20°C to 60°C.

[0026] In one embodiment of the present invention, the step of regenerating the carbon dioxide absorbent can be performed at a temperature of 100°C or lower.

[0027] In one embodiment of the present invention, the carbon dioxide recovery method may further include the step of reusing a regenerated absorbent from which carbon dioxide has been removed.

[0028] One embodiment of the present invention is illustrated in the accompanying drawings. However, the present creative concept may be embodied in many other forms and should not be interpreted as being limited to the embodiments described herein. Rather, these embodiments are provided to ensure that the present disclosure is thorough and complete and will sufficiently convey the scope of the present creative concept to those skilled in the art. Identical reference numerals denote identical components.

[0029] The terms used herein are intended to describe specific embodiments only and are not intended to limit the creative concept. The singular form used herein is intended to include the plural form including "at least one" unless the content clearly indicates otherwise. "At least one" should not be interpreted as limiting to the singular. As used herein, the term "and / or" includes any combination of one or more of the listed items. The terms "comprising" and / or "comprising" as used in the detailed description specify the presence of the specified features, regions, integers, steps, actions, components, and / or components, and do not exclude the presence or addition of one or more other features, regions, integers, steps, actions, components, components, and / or groups thereof.

[0030] Unless otherwise defined, all terms used in this specification (including technical and scientific terms) have the same meaning as generally understood by those skilled in the art to which this disclosure pertains. Furthermore, it will also be understood that terms as defined in commonly used dictionaries should be interpreted as having a meaning consistent with their meaning within the context of the relevant technology and the content of this disclosure, and should not be interpreted in an idealized or overly formal sense.

[0031] Although specific embodiments have been described, alternatives, modifications, variations, improvements, and substantial equivalents that are not currently anticipated or cannot be anticipated may arise to the applicant or those skilled in the art. Accordingly, the appended claims, which may be filed and modified, are intended to include all such alternatives, modifications, variations, improvements, and substantial equivalents.

[0032] In the following embodiments, terms such as first, second, etc. are used not in a limiting sense, but for the purpose of distinguishing one component from another component.

[0033] In the following examples, singular expressions include plural expressions unless the context clearly indicates otherwise.

[0034] In the drawings, the size of components may be exaggerated or reduced for convenience of explanation. For example, the size and thickness of each component shown in the drawings are depicted arbitrarily for convenience of explanation, so the present invention is not necessarily limited to what is illustrated.

[0035] In the following embodiments, the x-axis, y-axis, and z-axis are not limited to three axes in an orthogonal coordinate system and can be interpreted in a broader sense that includes them. For example, the x-axis, y-axis, and z-axis may be orthogonal to each other, but they may also refer to different directions that are not orthogonal to each other.

[0036] Where an embodiment can be implemented differently, a specific process sequence may be performed differently from the order described. For example, two processes described consecutively may be performed substantially simultaneously or proceed in the reverse order of the description.

[0037] In one aspect, the present invention relates to a carbon dioxide absorbent, wherein the carbon dioxide absorbent may comprise N-methyldiethanolamine (MDEA), diethylaminoethanol (DEEA), and piperazine (PZ).

[0038] The carbon dioxide absorbent of the present invention has a higher carbon dioxide capture capacity compared to conventionally used absorbents and can regenerate the carbon dioxide absorbent at a lower temperature, thereby reducing the amount of absorbent and regeneration energy required for the process.

[0039] FIG. 1 is a schematic diagram of a system for capturing carbon dioxide with a carbon dioxide absorbent of the present invention, removing carbon dioxide to recover carbon dioxide, and regenerating the absorbent.

[0040] In one embodiment of the present invention, the carbon dioxide absorbent of the present invention can be used in a carbon dioxide capture system comprising a carbon dioxide absorption unit (110) and a carbon dioxide absorbent regeneration unit (120).

[0041] In the carbon dioxide absorption unit (110), a mixed gas containing carbon dioxide is injected into the carbon dioxide absorption unit equipped with an absorbent to selectively absorb carbon dioxide. When carbon dioxide and the carbon dioxide absorbent are mixed, a rich solution containing carbon dioxide can be formed, and the rich solution can be supplied to the carbon dioxide absorbent regeneration unit (120) to remove carbon dioxide. The carbon dioxide absorbent regeneration unit can remove carbon dioxide from the rich solution and regenerate the carbon dioxide absorbent. The removed carbon dioxide can be discharged from the regeneration unit and supplied to the carbon dioxide recovery unit, or can be stored separately through various physicochemical methods.

[0042] In one embodiment of the present invention, the carbon dioxide capture system may further include a reboiler. In order to facilitate the removal of carbon dioxide in the carbon dioxide regeneration unit, carbon dioxide can be removed and the absorbent regenerated by heat supplied from the reboiler. The regenerated absorbent can be reused through a resupply line (200) to the carbon dioxide absorption unit, and can be cooled before being supplied to the carbon dioxide absorption unit.

[0043] The carbon dioxide absorbent according to the present invention enables carbon dioxide removal and absorbent regeneration under temperature conditions of 100°C or lower, thereby reducing the thermal energy required for the process.

[0044] Generally, monoethanolamine (MEA), a primary amine, is the most widely used because it has the highest basicity and the smallest equivalent weight. Diethanolamine (DEA), a secondary amine, and triethanolamine (TEA), N-methyldiethanolamine (MDEA), and triisopropanolamine (TIPA), a tertiary amine, are also used. In the case of MDEA, although it has low corrosiveness and regeneration heat, it has the disadvantage of a low absorption rate. Regarding absorption technology, the technology utilizing a monoethanolamine absorption solution is representative. Initially, the ABB Lummus process using a 20% monoethanolamine absorption solution was used; however, with the development of corrosion additives, the Fluor Daniel process using a 30% monoethanolamine absorption solution was developed and is currently utilized as the representative standard amine process.

[0045] The present invention relates to a carbon dioxide absorbent comprising an amine mixture, and the mixed amine carbon dioxide absorbent according to the present invention has the effect of increasing the amount of carbon dioxide captured and saving energy required for absorbent regeneration.

[0046] In one embodiment of the present invention, the carbon dioxide absorbent comprises an amine mixture, and the amine mixture may include two or more selected from the group consisting of N-methyldiethanolamine (MDEA), dimethylaminoethylamine (DMEA), triethanolamine (TEA), diethylaminoethanolamine (DEEA), hydroxethylpiperazine (HEPZ), piperazine (PZ), 1-methylpiperazine (1-MePZ), and 2-methylpiperazine (2-MePZ). The amine compounds of the present invention are materials with relatively low biological / oxidative degradability, and a combination thereof can improve the performance of the carbon dioxide absorbent.

[0047] In one embodiment of the present invention, the carbon dioxide absorbent may use a combination of a tertiary amine compound and a secondary amine compound. For example, one or more selected from the group consisting of N-methyldiethanolamine (MDEA), dimethylaminoethylamine (DMEA), triethanolamine (TEA), and diethylaminoethanolamine (DEEA) may be adopted as the tertiary amine, and a mixture may be used in which one or more selected from the group consisting of hydroxethylpiperazine (HEPZ), piperazine (PZ), 1-methylpiperazine (1-MePZ), and 2-methylpiperazine (2-MePZ) are adopted and mixed.

[0048] The amine compounds of the present invention are organic compounds having nitrogen bonded to one, two, or three carbons, and can be classified into primary amines (RNH2), secondary amines (R2NH), and tertiary amines (R3N) depending on the number of substituted hydrogen atoms. In the carbon dioxide absorption reaction of the amine absorbent, carbamates and bicarbonates are generated as intermediates; these can be dissociated to regenerate the amine absorbent and remove and recover the carbon dioxide. Generally, the reaction between the primary and secondary amines of the carbon dioxide absorbent and carbon dioxide can occur via two main mechanisms: 1) Carbamates are formed by a nucleus reaction in which electron-donating substances such as OH-, CN-, NH3, and H2O attack a region of low electron density in the counterpart substance (2RNH2 + CO2 = RNHCOO). - +RNH3 + ) and 2) the formed carbamate is converted to bicarbonate by hydrolysis with water (2RNH2+CO2+H2O=RNH3 + +HCO3 - +RNH2) can occur. In this case, the reaction between the amine and carbon dioxide can form a carbamate through a 2:1 molar reaction. Due to this absorption mechanism, carbon dioxide absorbents using primary and secondary amines exhibit a faster absorption rate but lower absorption capacity when the reaction proceeds more toward the carbamate reaction, whereas a slower absorption rate but higher absorption capacity when the reaction proceeds more toward the bicarbonate reaction. Furthermore, since carbon dioxide is released in the reverse order, high regeneration energy is required.

[0049] In the case of tertiary amines, carbamates are not formed because there are no amino hydrogen atoms, and they can absorb carbon dioxide to form bicarbonates. By capturing one carbon dioxide molecule per amine molecule, they can have higher absorption performance than primary and secondary amines and enable the realization of a carbon dioxide absorbent with low regeneration energy.

[0050] In one embodiment of the present invention, the carbon dioxide absorbent may comprise a mixture of tertiary amine compounds, N-methyldiethanolamine (MDEA) and diethylaminoethanol (DEEA), and a secondary amine compound, piperazine (PZ). N-methyldiethanolamine (MDEA) and diethylaminoethanol (DEEA) are tertiary amines that have a high carbon dioxide absorption capacity, can reduce renewable energy consumption, and possess thermal stability. Piperazine can rapidly form a carbamate with carbon dioxide, thereby increasing the carbon dioxide absorption rate. Piperazine forms a carbamate with carbon dioxide to lower the initial carbon dioxide concentration, while N-methyldiethanolamine and diethylaminoethanol continuously absorb carbon dioxide to increase the total amount of carbon dioxide absorbed.

[0051] In one embodiment of the present invention, the piperazine may be included in a weight percent lower than that of N-methyldiethanolamine or diethylaminoethanol. If piperazine is added in a weight percent higher than that of N-methyldiethanolamine or diethylaminoethanol, the total carbon dioxide absorption amount is lowered, and the energy required to regenerate the absorbent may be increased.

[0052] In one embodiment of the present invention, the N-methyldiethanolamine may be included in an amount of 10% to 50% by weight, 10% to 40% by weight, 10% to 30% by weight, 10% to 20% by weight, 15% to 50% by weight, 15% to 40% by weight, 15% to 30% by weight, or 15% to 20% by weight, based on the total weight of the carbon dioxide absorbent. In a preferred embodiment, the N-methyldiethanolamine may be included in an amount of 15% to 20% by weight. If the N-methyldiethanolamine is included in the absorbent at a level lower than 10% by weight, the amount of carbon dioxide captured may decrease, and the energy required to regenerate the absorbent may increase. Additionally, if it is included at a level higher than 50% by weight, the carbon dioxide absorption rate may decrease.

[0053] In one embodiment of the present invention, the diethylaminoethanol may be included in an amount of 5% to 30% by weight, 5% to 20% by weight, 5% to 10% by weight, 10% to 30% by weight, 10% to 20% by weight, or 10% to 15% by weight, based on the total weight of the carbon dioxide absorbent. In a preferred embodiment, the diethylaminoethanol may be included in an amount of 10% to 15% by weight. If the diethylaminoethanol is included in the absorbent at a level lower than 5% by weight, the carbon dioxide capture rate may decrease, resulting in lower absorption efficiency. Additionally, if it is included at a level higher than 30% by weight, the energy required to regenerate the carbon dioxide absorbent may increase, and the possibility of degradation of the absorbent may increase.

[0054] In one embodiment of the present invention, the piperazine is present at an absorbent molal concentration of 0.5 m to 2.0 m, 0.5 m to 1.5 m, 0.5 m to 1.4 m, 0.5 m to 1.3 m, 0.5 m to 1.2 m, 0.5 m to 1.1 m, 0.5 m to 1.0 m, 0.8 m to 2.0 m, 0.8 m to 1.5 m, 0.8 m to 1.4 m, 0.8 m to 1.3 m, 0.8 m to 1.2 m, 0.8 m to 1.1 m, 0.8 m to 1.0 m, 0.9 m to 2.0 m, 0.9 m to 1.5 m, 0.9 m to 1.4 m, 0.9 m to 1.3 m, and 0.9 m to 1.2 m. It may be included at a molar concentration of 0.9 m to 1.1 m or 0.9 m to 1.0 m. If the piperazine is included at a molar concentration lower than 0.5 m, the total carbon dioxide absorption rate may be lowered, and if the piperazine is included at a molar concentration higher than 2.0 m, the energy required to regenerate the absorbent may be increased.

[0055] In one embodiment of the present invention, the carbon dioxide absorbent may further include water. In the carbon dioxide absorbent containing water of the present invention, carbon dioxide can be dissolved in water and converted into carbonic acid, and the carbonic acid can increase the reactivity of the amine component of the present invention, for example, N-methyldiethanolamine or diethylaminoethanol, to form a bicarbonate.

[0056] In one embodiment of the present invention, the carbon dioxide absorbent may comprise 10% to 50% by weight of N-methyldiethanolamine, 5% to 30% by weight of diethylaminoethanol, 0.5 m to 2.0 m of piperazine, and 15% to 80% by weight of water. In a preferred embodiment of the present invention, it may comprise 15% to 20% by weight of N-methyldiethanolamine, 10% to 15% by weight of diethylaminoethanol, and 0.9 m to 1.2 m of piperazine.

[0057] In another aspect, the present invention can provide a method for capturing carbon dioxide using a carbon dioxide absorbent.

[0058] The carbon dioxide capture method of the present invention may include the step of absorbing carbon dioxide from a gas mixture containing carbon dioxide using a carbon dioxide absorbent; and the step of regenerating the carbon dioxide absorbent by removing the carbon dioxide absorbed by the carbon dioxide absorbent.

[0059] The step of absorbing carbon dioxide can capture carbon dioxide using the carbon dioxide absorbent described above. The step of absorbing carbon dioxide according to the present invention can be performed by injecting a carbon dioxide-containing gas into a carbon dioxide absorbent so that the absorbent can absorb the carbon dioxide within the contained gas. The carbon dioxide-containing gas is, for example, exhaust gas or flue gas (hereinafter referred to as "exhaust gas, etc."), and the exhaust gas, etc. may include waste gases formed as final products of power generation or processes in various industrial fields, and such exhaust gas, etc. may contain a large amount of carbon dioxide.

[0060] When absorbing carbon dioxide, the amount of carbon dioxide absorbed may increase as the temperature decreases and the pressure increases. In one embodiment, when absorbing carbon dioxide, the temperature may be performed in a temperature range of 0°C to 80°C, preferably in a temperature range of 20°C to 60°C, and the pressure may be performed at atmospheric pressure to about 80 atmospheres, preferably atmospheric pressure to 60 atmospheres.

[0061] The step of regenerating the carbon dioxide absorbent is a step in which carbon dioxide is removed from the absorbent that has absorbed carbon dioxide and the carbon dioxide absorbent is regenerated. More specifically, the absorbent can be regenerated by applying heat to the absorbent that has absorbed carbon dioxide, and the carbamate or bicarbonate within the absorbent can be decomposed by the heat, thereby removing the carbon dioxide and regenerating the absorbent. In one embodiment, the step of regenerating the carbon dioxide absorbent can be performed at a temperature of 120°C or lower, more preferably at a temperature of 100°C or lower.

[0062] In one embodiment of the present invention, the carbon dioxide recovery method may further include a step of reusing a regenerated absorbent from which carbon dioxide has been removed. The regenerated absorbent from which carbon dioxide has been removed can be reused in the step of absorbing carbon dioxide to be reused for carbon dioxide capture.

[0063]

[0064] The present invention will be explained in detail below through examples and experimental examples.

[0065] However, the embodiments and experimental examples described below are merely specific examples of the present invention in one aspect, and the present invention is not limited thereto.

[0066]

[0067] Example

[0068] <Example 1> Preparation of Carbon Dioxide Absorbent CV-S1

[0069] A carbon dioxide absorbent was prepared in an aqueous solution containing 15 wt% N-methyldiethanolamine (MDEA), 15 wt% diethylaminoethanolamine (DEEA), and 1.2 m piperazine (PZ).

[0070]

[0071] <Example 2> Preparation of Carbon Dioxide Absorbent CV-S2

[0072] A carbon dioxide absorbent was prepared in an aqueous solution containing 20 wt% N-methyldiethanolamine (MDEA), 10 wt% diethylaminoethanolamine (DEEA), and 0.9 m piperazine (PZ).

[0073]

[0074] <Comparative Example 1> Preparation of carbon dioxide absorbent

[0075] A carbon dioxide absorbent in the form of an aqueous solution containing 30% by weight of monoethanolamine (MEA) was prepared.

[0076]

[0077] <Test Example 1> Performance Evaluation of Small-Volume Batch Carbon Dioxide Absorbent

[0078] To evaluate the performance of the carbon dioxide absorbent CV-S1 of Example 1 and the CV-S2 of Example 2 prepared according to Examples 1 and 2, the CO2 loading capacity and specific reboiler duty (SRD) performance were evaluated using a solvent screening system (SSS) under the same experimental conditions. The solvent screening system used a small-capacity batch carbon dioxide capture absorbent evaluation device to evaluate the effect of the absorbent of the present invention.

[0079] The carbon dioxide absorption experiment was conducted up to the saturation level of the carbon dioxide absorbents in Example 1, Example 2, and Comparative Example 1 according to the carbon dioxide sensor, and the carbon dioxide content was quantified by gravimetric measurement. Each carbon dioxide absorbent was 150g, the gas composition was 30% CO2, 70% N2, and the gas flow rate was 1.0L / min.

[0080] Specific reboiler duty (SRD) evaluation was performed to assess the energy required for the regeneration of carbon dioxide absorbents. Regeneration is the process of removing carbon dioxide from absorbents that have absorbed carbon dioxide; the SRD evaluation considered the minimum (theoretical) and maximum (actual) values ​​by applying correction factors obtained from the theoretically required energy and actual experimental values.

[0081] To evaluate the SRD, the experiment was conducted under a temperature gradient from 25°C to 100°C and a constant condenser temperature of 0°C, and nitrogen gas was injected during the experiment to promote the release of carbon dioxide from the saturated carbon dioxide absorbent. The results are shown in Table 1 and Figure 2 below.

[0082] Referring to Table 1, it was confirmed that Examples 1 and 2 had a carbon dioxide capture capacity of 0.58 mol CO2 / mol amine. On the other hand, the absorbent of Comparative Example 1 showed a carbon dioxide capture capacity of 0.47 mol CO2 / mol amine, and the absorbents of Examples 1 and 2 exhibited superior carbon dioxide absorbent performance with a higher capture capacity than the absorbent of Comparative Example 1.

[0083] Classification Absorbent Component Carbon Dioxide Capture Capacity (in mol CO2 / mol amine) Comparative Example 1 MEA (30 wt%) 0.47 Example 1 MDEA / DEEA / PZ (15 wt% / 15 wt% / 1.2 m) 0.58 Example 2 MDEA / DEEA / PZ (20 wt% / 10 wt% / 0.9 m) 0.58

[0084] Referring to Figure 2, regarding SRD performance, the absorbent of Example 1 showed a 24% reduction in SRD compared to Comparative Example 1, and Example 2 showed a 15% reduction in SRD, confirming that the energy required to regenerate the absorbent can be reduced compared to the monoethanolamine absorbent.

[0085] <Test Example 2> Performance Evaluation of a 95℃ Reboiler Large Capacity Carbon Dioxide Capture System

[0086] The performance evaluation of the large-capacity carbon dioxide capture system was tested under conditions similar to those of a general carbon dioxide capture system. Experiments were conducted up to the saturation level of the carbon dioxide absorbents of Example 1, Example 2, and Comparative Example 1 according to the carbon dioxide sensor, and the carbon dioxide content was quantified by gravimetric measurement. Each carbon dioxide absorbent was 10 kg, the gas composition was 15% CO2 and 85% N2, the total gas flow rate was 14 L / min (CO2 = 2.10 L / min, N2 = 11.90 L / min), the absorbent flow rate was 1.0 L / min, and the G / L ratio was 14.

[0087] Specific reboiler duty (SRD) evaluation was conducted with 10 kg of carbon dioxide absorbent, gas composition of 50% CO2 and 50% N2, gas flow rate of 9.0 L / min, G / L ratios of 10, 20, 30, 40, and 50, and a reboiler temperature of 95 ℃. The results are shown in Table 2, Figures 3 and 4 below.

[0088] Referring to Table 2, the capture capacity of each absorbent showed different results from those confirmed in Test Example 1. The absorbent of Example 1 was confirmed to have a capacity of 0.77 mol CO2 / mol amine, and the absorbent of Example 2 was confirmed to have a capacity of 0.70 mol CO2 / mol amine. These results confirmed that they have a significantly superior carbon dioxide capture capacity compared to the 0.52 mol CO2 / mol amine capacity of the absorbent of Comparative Example 1. In particular, the capture capacity of the absorbent of Example 1 was measured to be 46% higher than that of the absorbent of Comparative Example 1, and the capture capacity of the absorbent of Example 2 was measured to be 35% higher.

[0089] Classification Absorbent Component Carbon Dioxide Capture Capacity (in mol CO2 / mol amine) Comparative Example 1 MEA (30 wt%) 0.52 Example 1 MDEA / DEEA / PZ (15 wt% / 15 wt% / 1.2) 0.77 Example 2 MDEA / DEEA / PZ (20 wt% / 10 wt% / 0.9 m) 0.70

[0090] Referring to FIG. 3, which is a graph showing the carbon dioxide removal efficiency with respect to the G / L ratio at 95°C, the absorbents of Examples 1 and 2 exhibited superior carbon dioxide removal efficiency compared to Comparative Example 1 when the G / L ratio ranged from 20 to 50; in particular, at a G / L ratio of 40, the carbon dioxide removal efficiency was measured to be approximately four times higher than that of Comparative Example 1. It was confirmed that the carbon dioxide capture rate remained high even under operating conditions where the G / L ratio increased, and that the regeneration performance of the carbon dioxide absorbent at 95°C was excellent. The SRD data for the absorbents of Examples 1 and 2 at 95°C is shown in FIG. 4. According to FIG. 4(a), the absorbents of Examples 1 and 2 showed reduction rates of 71% and 56%, respectively, at a G / L ratio of 10, exhibiting significantly reduced SRD values ​​compared to the absorbent of Comparative Example 1. Excellent SRD reduction rates were observed in G / L 20 to 40 in FIGS. 4(b) to 4(d), and according to FIG. 4(e), it was confirmed that the absorbents of Examples 1 and 2 showed superior absorbent regeneration performance compared to the absorbent of Comparative Example 1, with SRD reduction rates of 43% and 27%, respectively, even at G / L 50.

[0091]

[0092] <Test Example 3> Performance Evaluation of a 100℃ Reboiler Large Capacity Carbon Dioxide Capture System

[0093] Under the same conditions as Test Example 2 above, the reboiler temperature was set to 100°C to evaluate the performance of the carbon dioxide capture system. Similar to Test Example 2, the carbon dioxide absorption experiment was conducted until the carbon dioxide absorbents of Example 1, Example 2, and Comparative Example 1 reached saturation according to the carbon dioxide sensor, and the carbon dioxide content was quantified by gravimetric measurement. Each carbon dioxide absorbent was 10 kg, the gas composition was 15% CO2 and 85% N2, the total gas flow rate was 14 L / min (CO2 = 2.10 L / min, N2 = 11.90 L / min), the absorbent flow rate was 1.0 L / min, and the G / L ratio was 14.

[0094] Specific reboiler duty (SRD) evaluation was conducted with 10 kg of carbon dioxide absorbent, gas composition of 50% CO2 and 50% N2, gas flow rate of 9.0 L / min, G / L ratios of 10, 20, 30, 40, and 50, and reboiler temperature of 100 ℃. The results are shown in Table 3, Figures 5 and 6 below.

[0095] Referring to FIG. 5, the carbon dioxide removal efficiency of the absorbents in Examples 1 and 2 was 100% at G / L ratios of 40 and 50, while the removal efficiency of the absorbent in Comparative Example 1 was measured to be 40%. It was confirmed that the carbon dioxide removal efficiency of the absorbents in Examples 1 and 2 according to the present invention exhibited performance 2.5 times better than that of Comparative Example 1. When comparing the fact that the absorbents in Examples 1 and 2 of the present invention showed more than 4 times the performance of the absorbent in Comparative Example 1 at a reboiler temperature of 95°C in the above test, and showed lower efficiency than Comparative Example 1 at a G / L ratio of 20, it suggests that the absorbents of the examples of the present invention exhibit superior performance in removing carbon dioxide absorbed by the carbon dioxide absorbent compared to Comparative Example 1 at lower reboiler temperatures.

[0096] Classification Absorbent Component Carbon Dioxide Capture Capacity (in mol CO2 / mol amine) Comparative Example 1 MEA (30 wt%) 0.52 Example 1 MDEA / DEEA / PZ (15 wt% / 15 wt% / 1.2 m) 0.77 Example 2 MDEA / DEEA / PZ (20 wt% / 10 wt% / 0.9 m) 0.70

[0097] The SRD data of the absorbents of Examples 1 and 2 at 100°C are shown in FIG. 6. Referring to FIG. 6, it was confirmed that the absorbents of Examples 1 and 2 showed an increase in SRD compared to the absorbent of Comparative Example 1, with 9% and 34%, respectively, at a G / L ratio of 10, as shown in FIG. 6(a). The SRD also increased at G / L ratios of 20 and 30 in FIG. 6(b). These results are very different from the 95°C test results of Test Example 2, suggesting that the performance of the absorbents of the examples of the present invention is superior at lower temperatures. On the other hand, at a G / L ratio of 40 in Fig. 6(d) and a G / L ratio of 50 in Fig. 6(e), the SRD was reduced, and at a G / L ratio of 50, the SRD reduction rates of the absorbents in Examples 1 and 2 were 31% and 16%, respectively, confirming that they exhibited superior performance compared to the absorbent in Comparative Example 1. The absorbents in Examples 1 and 2 of the present invention can maintain a carbon dioxide capture rate even at high G / L ratios, significantly reduce the regeneration energy required for absorbent regeneration compared to Comparative Example 1, and exhibit superior efficiency at low temperatures, thereby reducing the energy required for the carbon dioxide capture process.

[0098]

[0099] The foregoing description of the present invention is for illustrative purposes only, and those skilled in the art will understand that other specific forms can be easily modified without altering the technical spirit or essential features of the present invention. Therefore, the embodiments described above should be understood as illustrative in all respects and not restrictive. For example, each component described as a single unit may be implemented in a distributed manner, and components described as distributed may likewise be implemented in a combined form.

[0100] The scope of the present invention is defined by the claims set forth below, and all modifications or variations derived from the meaning and scope of the claims and equivalent concepts thereof should be interpreted as being included within the scope of the present invention.

Claims

1. Comprising N-methyldiethanolamine (MDEA), diethylaminoethanol (DEEA) and piperazine (PZ), Mixed amine carbon dioxide absorbent.

2. In Paragraph 1, The piperazine is included in a weight percent lower than that of N-methyldiethanolamine or diethylaminoethanol, Mixed amine carbon dioxide absorbent.

3. In Paragraph 1, The N-methyldiethanolamine is included in an amount of 10% to 50% by weight relative to the total weight of the carbon dioxide absorbent. Mixed amine carbon dioxide absorbent.

4. In Paragraph 1, The diethylaminoethanol comprises 5% to 30% by weight relative to the total weight of the carbon dioxide absorbent. Mixed amine carbon dioxide absorbent.

5. In Paragraph 1, The piperazine is contained at a concentration of 0.5 m to 2.0 m with respect to the total weight of the carbon dioxide absorbent, Mixed amine carbon dioxide absorbent.

6. In Paragraph 1, The above carbon dioxide absorbent further contains water, Mixed amine carbon dioxide absorbent.

7. As a carbon dioxide capture method, The above method comprises the step of absorbing carbon dioxide from a gas mixture containing carbon dioxide using a mixed amine carbon dioxide absorbent according to any one of claims 1 to 6; and, A method comprising the step of regenerating the carbon dioxide absorbent by removing carbon dioxide absorbed by the carbon dioxide absorbent. Carbon dioxide capture method.

8. In Paragraph 7, The step of absorbing carbon dioxide is performed in a temperature range of 20 ℃ to 60 ℃, Carbon dioxide capture method.

9. In Paragraph 7, The step of regenerating the carbon dioxide absorbent is performed at a temperature of 100°C or lower, Carbon dioxide capture method.

10. In Paragraph 7, The above carbon dioxide recovery method further includes the step of reusing a regenerated absorbent from which carbon dioxide has been removed. Carbon dioxide capture method.

Images