KR102112673B1 - Sulfur dioxide-resistant amine-based carbon dioxide adsorbent with core-shell structure and method for manufacturing thereof - Google Patents

Abstract

The present invention relates to a core-shell type amine-based carbon dioxide adsorbent resistant to sulfur dioxide and a method for manufacturing the same, and more specifically, a core portion having a high specific gravity of primary or secondary amine selectively adsorbs carbon dioxide, and tertiary It relates to a core-shell type amine-based carbon dioxide adsorbent having a resistance to sulfur dioxide, characterized in that the shell portion having a high specific gravity of amine is resistant from inertness by sulfur dioxide, and a method for manufacturing the same. The core-shell type amine-based carbon dioxide adsorbent having resistance from sulfur dioxide according to the present invention is an adsorbent having a porous carrier having an amine compound immobilized therein as a core, and an amine layer having resistance from inactivity by sulfur dioxide as a shell, a sulfur dioxide resistant amine layer In the case of a typical amine-based carbon dioxide adsorbent without this, the sulfur dioxide contained in the flue gas during the carbon dioxide capture process irreversibly adsorbs to the amine, and thus suffers serious inertness. On the other hand, the amine-based carbon dioxide adsorbent having a core-shell structure having a sulfur dioxide-resistant amine layer according to the present invention serves to protect the amine compound of the core by selectively adsorbing sulfur dioxide to the sulfur dioxide-resistant amine layer of the shell portion The amine compound of can adsorb only carbon dioxide selectively. In addition, since the sulfur dioxide adsorbed on the shell portion is easily desorbed at about 110 ° C., it exhibits dramatically improved regeneration stability in a temperature shift adsorption process containing sulfur dioxide.

Description

{Sulfur dioxide-resistant amine-based carbon dioxide adsorbent with core-shell structure and method for manufacturing thereof}

The present invention relates to a core-shell type amine-based carbon dioxide adsorbent resistant to sulfur dioxide and a method for manufacturing the same, and more specifically, a core portion having a high specific gravity of primary or secondary amine selectively adsorbs carbon dioxide, and tertiary It relates to a core-shell type amine-based carbon dioxide adsorbent having a resistance to sulfur dioxide, characterized in that the shell portion having a high specific gravity of amine is resistant from inertness by sulfur dioxide, and a method for manufacturing the same.

Techniques for selectively collecting carbon dioxide from the flue gas of a thermal power plant include a wet absorption method, a dry adsorption method, a membrane separation method, and a deep cooling method. Among these, the most widely used and high technical completeness is a wet absorption method using a monoethanolamine (MEA) aqueous solution, by reacting carbon dioxide in the flue gas with a MEA aqueous solution diluted to 30% or less, absorbing it, and heating the solution. It is a method of separating high concentrations of carbon dioxide and simultaneously regenerating MEA. Since the wet absorption method is an aqueous solution-based process, it is easy to heat exchange and has the advantage of having high carbon dioxide selectivity due to strong adsorption heat of amines. However, it requires a lot of energy in the process of regenerating the amine aqueous solution, and there are disadvantages such as loss of amine molecules and corrosion of equipment. This is a very uneconomical technology at the present time because cost and scale-up problems are very sensitive in industrial sites where large-scale greenhouse gases need to be processed. For this reason, amine-based dry adsorbents, which have low energy and high carbon dioxide selectivity, are emerging as new alternatives.

The amine-based dry adsorbent adsorbs carbon dioxide through strong chemical bonding between carbon dioxide and amine, as in the wet absorption method using an amine aqueous solution. In the case of such a dry adsorbent, it exhibits high carbon dioxide selectivity, and by using a carrier having a high porosity, it is possible to maximize its adsorption capacity by increasing the amine loading amount. As a representative example, a study has been reported that the adsorption capacity of carbon dioxide can be dramatically increased by maximally supporting an amine polymer on a silica carrier having a very large pore volume (Zhang, H. et al., RSC Adv. 4, 2014, 19403-19417). Many studies on these amine-based dry adsorbents have been focused on showing the maximum value of carbon dioxide adsorption performance by effectively supporting the maximum amine polymer through structural adjustment of the amine carrier. However, for the long-term operation of the adsorbent in the actual process, not only maximization of adsorption performance but also regeneration stability of the adsorbent should be additionally considered, but research on such regeneration stability is insufficient.

Indeed, amine-based adsorbents are inert by various gases present in the flue gas. When the hydrothermal stability of the amine carrier is low, when exposed to steam at high temperatures, the performance of the adsorbent is reduced due to structural deformation of the carrier. In addition, it is known that when amine is exposed to high-temperature dried carbon dioxide during the regeneration process, it undergoes rapid deactivation due to the formation of urea, and also suffers severe inactivation by acid gases such as oxygen and sulfur dioxide. In particular, in the case of inactivation by sulfur dioxide, all amine types tend to selectively adsorb sulfur dioxide compared to carbon dioxide, and due to irreversible adsorption of sulfur dioxide, regeneration does not occur even at high temperatures, which is a serious problem in long-term operation of the adsorbent. do. According to a report from the Georgia Institute of Technology's Jones, CW group, primary or secondary amines strongly adsorb sulfur dioxide and thermally stable salts are formed, so that the adsorbents are not regenerated even under high temperature regeneration conditions ( Rezaei, F. et al., Ind. Eng. Chem. Res. 52, 2013, 12192-12201). Therefore, when using an amine-based adsorbent, it is preferable to undergo a flue gas desulfurization (FGD) process in a step before carbon dioxide capture to minimize deactivation by sulfur dioxide.

Generally, the flue gas generated in the post-combustion capture process contains about 2000 ppm of sulfur dioxide. The FGD process used to remove the high concentration of sulfur dioxide includes wet FGD, semidry FGD, dry FGD, and ammonium FGD. Among them, the FGD process, which is currently most widely used due to its economical and high desulfurization efficiency, is a wet-limestone FGD process using limestone (Srivastava, RK et al., J. Air Waste Manag. Assoc. 51, 2001, 1676-1688). Since a typical wet-limestone FGD process has a desulfurization efficiency of about 90%, the sulfur dioxide concentration after the FGD process is about 200 ppm. However, for long-term operation of the amine-based adsorbent, it is preferable that the sulfur dioxide concentration is further lowered in tens of ppm units, and for this, an additional desulfurization facility such as a sulfur dioxide filter is required. Therefore, it is necessary to develop a carbon dioxide adsorbent that is resistant to deactivation by sulfur dioxide for process design considering economics.

According to the announcement by Sayari Group of Ottawa University, in the case of tertiary amine, sulfur dioxide is weakly adsorbed compared to primary and secondary amines, and deactivation is possible in a continuous process containing sulfur dioxide because it can be easily desorbed at a high temperature of about 120 ℃. It does not occur and is stable (Tailor, R. et al., Environ. Sci. Technol. 48, 2014, 2025-2034). However, tertiary amine has a low carbon dioxide adsorption strength and low selectivity, so it is difficult to apply it to a capture process after combustion with a low carbon dioxide concentration (<15%) in adsorption conditions. Similarly, Korean Patent Registration No. 10-1495876 discloses a tertiary amine-based sulfur dioxide absorbent having a nitrile functional group. Although this invention discloses a tertiary amine-based compound which is excellent in sulfur dioxide absorption and easy to desorb, it consists of tertiary amines having weak carbon dioxide adsorption strength, and thus selectively absorbs sulfur dioxide compared to carbon dioxide, thereby selectively absorbing a large amount of carbon dioxide. There is a disadvantage that it is difficult to be used in the carbon dioxide capture process after combustion, which must be collected.

Thus, the present inventors, as a result of great effort to develop a dry carbon dioxide adsorbent having excellent regeneration stability in a process containing sulfur dioxide, while having excellent adsorption selectivity to carbon dioxide, a core-shell (core-shell) resistant from inertness by sulfur dioxide ) By preparing an amine-based carbon dioxide adsorbent having a structure, it has been confirmed that it has not only carbon dioxide adsorption performance, but also significantly improved regeneration stability in a process containing sulfur dioxide, and thus completes the present invention.

An object of the present invention is to provide an amine-based carbon dioxide adsorbent having excellent regeneration stability in a process containing sulfur dioxide while having excellent adsorption selectivity to carbon dioxide.

Another object of the present invention is to provide a method for preparing the amine-based carbon dioxide adsorbent.

Another object of the present invention is to provide a method for adsorbing carbon dioxide using the adsorbent.

In order to achieve the above object, the present invention is a core containing an amine compound and a porous carrier; It provides a carbon dioxide adsorbent having a core-shell structure including; and a shell containing a sulfur dioxide-resistant amine compound coated surrounding the core.

The present invention also, (a) immobilizing the amine compound on a porous carrier; (b) adding a solution prepared by dissolving epoxide in a solvent to an amine compound immobilized on the carrier; (c) reacting an amine compound fixed to the carrier with an epoxide to form a sulfur dioxide resistant amine layer; And (d) removing the solvent to obtain a carbon dioxide adsorbent comprising a sulfur dioxide resistant amine layer.

The present invention also provides a method for adsorbing carbon dioxide using the adsorbent.

The core-shell type amine-based carbon dioxide adsorbent having resistance from sulfur dioxide according to the present invention is an adsorbent having a porous carrier having an amine compound immobilized therein as a core, and an amine layer having resistance from inactivity by sulfur dioxide as a shell, a sulfur dioxide resistant amine layer In the case of a typical amine-based carbon dioxide adsorbent without this, the sulfur dioxide contained in the flue gas during the carbon dioxide capture process irreversibly adsorbs to the amine, and thus suffers serious inertness. On the other hand, the amine-based carbon dioxide adsorbent having a core-shell structure having a sulfur dioxide-resistant amine layer according to the present invention serves to protect the amine compound of the core by selectively adsorbing sulfur dioxide on the shell portion of the sulfur dioxide-resistant amine layer At the same time, the amine compound in the core portion can selectively adsorb only carbon dioxide. In addition, since the sulfur dioxide adsorbed on the shell portion is easily desorbed at about 110 ° C, it exhibits dramatically improved regeneration stability in a temperature swing adsorption (TSA) process containing sulfur dioxide.

1 is a cross-sectional view of an amine-based carbon dioxide adsorbent having a core-shell structure according to an embodiment of the present invention.
Figure 2 is a schematic view showing the process of forming a sulfur dioxide resistant amine layer by treating an epoxide on a porous carrier having an amine immobilized according to an embodiment of the present invention.
Figure 3 shows the results of analyzing the amine composition of the adsorbent according to an embodiment of the present invention by elemental analysis (EA) and X-ray photoelectron spectroscopy (XPS).
Figure 4 shows the results of analyzing the adsorption amount of carbon dioxide adsorbent according to an embodiment of the present invention.
Figure 5 shows the results of analyzing the carbon dioxide adsorption / desorption performance of the adsorbent according to an embodiment of the present invention at intervals of 10 cycles.

The present invention can be achieved by the following description. It should be understood that the following description describes preferred specific examples of the invention, and the invention is not necessarily limited thereto. In addition, the accompanying drawings are intended to aid understanding, and the present invention is not limited thereto, and details regarding individual configurations may be appropriately understood by the specific purpose of related descriptions to be described later.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by a person skilled in the art to which the present invention pertains. In general, the nomenclature used herein is well known and commonly used in the art.

In the present invention, when preparing an adsorbent having a porous carrier having a fixed amine compound as a core and having an amine layer having a resistance from inertness due to sulfur dioxide as a shell, sulfur dioxide contained in the exhaust gas during the carbon dioxide capture process irreversibly adsorbs to the amine It can be solved the problem of severe inertness due to this, and it was confirmed that the carbon dioxide adsorption performance, as well as significantly improved regeneration stability in the process containing sulfur dioxide.

Accordingly, the present invention, in one aspect, a core containing an amine compound and a porous carrier; And a shell containing a sulfur dioxide-resistant amine compound coated around the core; and to a carbon dioxide adsorbent having a core-shell structure.

In another aspect, the present invention, (a) immobilizing an amine compound on a porous carrier; (b) adding a solution prepared by dissolving epoxide in a solvent to an amine compound immobilized on the carrier; (c) reacting an amine compound fixed to the carrier with an epoxide to form a sulfur dioxide resistant amine layer; And (d) relates to a method for producing a carbon dioxide adsorbent having a core-shell structure, comprising removing the solvent to obtain a carbon dioxide adsorbent containing a sulfur dioxide resistant amine layer.

In the present invention, the amine compound of the shell portion is composed of an amine compound having a hydroxy group-containing carbon chain, and is composed of a basic skeleton unit represented by-[(CH ₂ ) _m (OH) _n NX] _y . Here, m is an integer from 1 to 20, n is an integer from 1 to 10, and y is an integer from 1 to 100. Preferably m is 2 to 10, n is 1 to 5, and y is 5 to 20. X is hydrogen, C1 ~ C18 alkyl, C3 ~ C10 cycloalkyl, C1 ~ C18 alkoxy, -CH = CH ₂ , -CH = CHCH ₂ CH ₃ , -CH ₂ CH = CHCH ₃ , -CH ₂ CH ₂ CH = CH ₂ , -CH = CHCH ₂ CH ₂ CH ₂ CH ₃ , -CH ₂ CH = CHCH ₂ CH ₂ CH ₃ , -CH ₂ CH ₂ CH = CHCH ₂ CH ₃ , -CH ₂ CH ₂ CH ₂ CH = CHCH ₃ , -CH ₂ CH ₂ CH ₂ CH ₂ CH = CH ₂ , -CH = CHCH ₂ CH ₂ CH ₂ CH ₂ CH ₂ CH ₃ , -CH ₂ CH = CHCH ₂ CH ₂ CH ₂ CH ₂ CH ₃ , -CH ₂ CH ₂ CH = CHCH ₂ CH ₂ CH ₂ CH ₃ , -CH ₂ CH ₂ CH ₂ CH = CHCH ₂ CH ₂ CH ₃ , -CH ₂ CH ₂ CH ₂ CH ₂ CH = CHCH ₂ CH ₃ , -CH ₂ CH ₂ CH ₂ CH ₂ CH ₂ CH = CHCH ₃ , -CH ₂ CH ₂ CH ₂ CH ₂ CH ₂ CH ₂ CH = CH ₂ , -CH ₂ O (CH ₂ ) ₃ Si (OCH ₃ ) ₃ , -CH ₂ O (CH ₂ ) ₃ Si (OCH ₂ CH ₃ ) ₃ , -CH ₂ O (CH ₂ ) ₂ CH ₃ , -CH ₂ O (CH ₂ ) ₃ CH ₃ , -CH ₂ OCH = CHCH ₃ , or -CH ₂ OCH ₂ CH = CH ₂ , and preferably C1 to C18 alkyl. Examples of more specific X may include methyl, ethyl, propyl, butyl, pentyl, hexyl, and the like.

In the present invention, the sulfur dioxide-resistant amine layer of the shell may have a proportion of nitrogen present as a tertiary amine in the nitrogen atom may be 50% to 100%, preferably 70% or more. When the proportion of nitrogen present as a tertiary amine is lower than 50%, there arises a problem that deactivation by irreversible adsorption of sulfur dioxide to primary and secondary amines is further accelerated.

In the present invention, the sulfur dioxide-resistant amine layer of the shell may be present in an amount of 0.1% to 30% by weight of the entire adsorbent, preferably 5% to 20% by weight. When the sulfur dioxide-resistant amine compound (amine layer) of the shell is less than 0.1% by weight relative to the total amount of the adsorbent, the shell portion is too thin to protect the amine active material of the core from irreversible adsorption of sulfur dioxide, and when it exceeds 30% by weight, Due to the increase in the total amount of adsorbent, there is a problem that the carbon dioxide adsorption capacity decreases.

In the present invention, the amine compound of the core includes a unit skeleton structure of-[(CH ₂ ) _x -NR] _y -and-[(CH ₂ ) _x -NH ₂ ], wherein each R in the unit structure is It can be hydrogen or hydrocarbon or branched chain. Specifically, the amine compound of the core may include a polyalkyleneimine such as a polyethyleneimine basic structure (when x = 2) or a polypropyleneimine basic structure (when x = 3), and x = 2-6 , y = 1 to 100 represents the number of repeating units formed.

In the present invention, the amine compound of the core includes all compounds containing a primary amine, a secondary amine, or a tertiary amine in the molecular structure. Non-limiting examples thereof include polyalkyleneimine such as polyethylenimine or polypropylenimine, and at least one of nitrogen atoms in the polyalkyleneimine polymer is modified with a hydroxy group-containing carbon chain. Amine polymer, 3- (aminopropyl) -trimethoxysilane, trimethoxy (3- (methylamino) propyl] silane), (N, Such as N-dimethylaminopropyl) trimethoxysilane, or N- (3-trimethoxysilylpropyl) diethylenetriamine Aminosilane may be included. More preferably, at least one of the nitrogen atoms in the polyalkyleneimine or polyalkyleneimine polymer is modified with a hydroxy group-containing carbon chain in consideration of the content of nitrogen atoms per unit molecular structure and suppression of urea formation. It can be a polymer.

In the present invention, the amine compound of the core may be present in an amount of 5% to 75% by weight of the whole adsorbent, preferably 10% to 65% by weight. When the amine compound of the core is less than 5% by weight based on the total amount of the adsorbent, the amount of carbon dioxide adsorption is reduced to less than 1%, and when it exceeds 75% by weight, the efficiency of the amine for carbon dioxide adsorption is reduced because too much amine is supported. Problem occurs.

In the present invention, the amine compound of the core portion is fixed to the porous carrier. As a method of fixing the amine compound to the carrier, it is possible to graft using a functional group such as a surface hydroxy group of the carrier or to impregnate the pores of the carrier. At this time, the carrier may be a porous carrier having a porosity of 0.1 cc / g to 5 cc / g. When the porosity of the porous carrier is less than 0.1 cc / g, there is a limit to the amount capable of supporting or functionalizing the amine, so that sufficient carbon dioxide adsorption capacity cannot be elicited. When it exceeds 5 cc / g, the wall thickness of the carrier Because it is too thin, mechanical stiffness is reduced and cannot be used for fluidized bed reactions.

In the present invention, the porous carrier of the core may be present in an amount of 20% by weight to 90% by weight of the entire adsorbent, preferably 30% by weight to 80% by weight. When the porous carrier of the core is less than 20% by weight based on the total amount of the adsorbent, the amine efficiency decreases due to the amine carried in excess, and there is a problem that the amine is lost at high temperature, and when it exceeds 90% by weight, the specific gravity of the amine as the active material Too few carbon dioxide adsorption capacity is reduced.

In the present invention, the molar ratio of nitrogen atom: epoxide present in the amine compound immobilized on the carrier is preferably 1: 0.2 to 1: 1. When the molar ratio is less than 1: 0.2, there is a problem that deactivation occurs due to the production of urea when exposed to high-temperature dried carbon dioxide, which is a regeneration condition, and when it exceeds 1: 1, the amine compound itself mass Due to the increase of the carbon dioxide adsorption efficiency is reduced.

In the present invention, the epoxide is a group consisting of 1,2-epoxyethane, 1,2-epoxypropane, 1,2-epoxybutane, 1,2-epoxypentane and 1,2-epoxyhexane It is preferably one or more selected from, and 1,2-epoxybutane is more preferable.

In addition, in the present invention, in the case of the "10-EB-PEI / SiO ₂ " adsorbent in which the sulfur dioxide resistant amine layer does not exist, the adsorption capacity gradually decreases as the adsorption / desorption cycle is repeated, while the adsorbent has a core and additional amine-epoxy Through side reactions, it was confirmed that in the case of core-shell type adsorbents having a high-order amine layer as a shell, the regeneration stability was dramatically improved.

Therefore, in another aspect, the present invention relates to a method for adsorbing carbon dioxide using the adsorbent.

Hereinafter, the present invention will be described in more detail by examples. It will be apparent to those skilled in the art that these examples are merely for more specifically describing the present invention, and the scope of the present invention is not limited to these examples.

Example 1. Preparation of an amine-based carbon dioxide adsorbent having a core-shell structure

The preparation of the amine-based carbon dioxide adsorbent having a core-shell structure started from the step of supporting the amine compound on a porous carrier. Fumed silica was used as the porous carrier, and an amine polymer in which nitrogen atoms in the polyethyleneimine (PEI) polymer was modified with a carbon chain containing a hydroxy group was used as the amine compound. The synthesis of modified polyethyleneimine was prepared by reacting 1,2-epoxybutane (1,2-Epoxybutane, EB) with polyethyleneimine. First, 2 g of polyethyleneimine (M _n = 1200, 19 mmol N / g) at 25 ° C. was dissolved in 4 g of methanol and stirred at a constant rate of 400 rpm for 10 minutes. Thereafter, 1,2-epoxybutane was added to the stirred polyethyleneimine / methanol solution, and 1.2 g of the 1,2-epoxybutane to polyethyleneimine was added at a ratio of 10 to 1.2 g, and additionally at 400 rpm for 12 hours. Stirring was performed at a rate to synthesize a modified polyethyleneimine / methanol solution. As a method of supporting the modified polyethyleneimine / methanol solution in the fumed silica pore, an incipient wetness impregnation method was used. Then, heat treatment was performed in a vacuum oven at 80 ° C. for 12 hours to completely remove the solvent from the material. The silica adsorbent carrying the modified polyethyleneimine prepared by the above method was designated as "10-EB-PEI / SiO ₂ ".

An additional amine-epoxide reaction was performed to form a shell composed of a sulfur dioxide resistant amine layer on the surface of the "10-EB-PEI / SiO ₂ " adsorbent. First, 1,2-epoxybutane and 0.08 g were dissolved in 1.6 mL of hexane to prepare a 1,2-epoxybutane solution. The 1,2-epoxybutane solution was loaded with 10-EB-PEI / SiO ₂ , 4 g, and then heat-treated at 60 ° C. for 24 hours in a sealed state to perform an amine-epoxide reaction. Then, in order to completely remove the solvent, an adsorbent having a core-shell structure was prepared by heat treatment in a vacuum oven at 80 ° C. for 12 hours. The adsorbent of the core-shell structure prepared by the above method was designated as "10-1-EB-PEI / SiO ₂ ".

In the process of preparing "10-1-EB-PEI / SiO ₂ ", 1,2-epoxybutane and 0.12 g were dissolved in 1.6 mL of hexane to prepare 1,2-epoxybutane solution. In the same manner, an adsorbent having a core-shell structure was prepared. The adsorbent of the core-shell structure prepared by the above method was designated as "10-1.5-EB-PEI / SiO ₂ ".

In the process of preparing the "10-1-EB-PEI / SiO ₂ ", 1,2-epoxybutane and 0.16 g were dissolved in 1.6 mL of hexane to prepare a 1,2-epoxybutane solution. In the same manner, an adsorbent having a core-shell structure was prepared. The adsorbent of the core-shell structure prepared by the above method was designated as "10-2-EB-PEI / SiO ₂ ".

Example 2. Analysis of physicochemical properties of amine-based carbon dioxide adsorbent having a core-shell structure

Analysis of the physicochemical properties of the adsorbent prepared in Example 1 was performed in the following manner, and will be described in detail as follows with reference to FIG. 3.

First, elemental analysis (EA) and X-ray photoelectron spectroscopy (XPS) were used to analyze the composition of the amine compound immobilized on the adsorbent prepared in Example 1. Heat treatment was performed for 12 hours in a vacuum oven at 100 ° C. for all adsorbents before each analysis. FIG. 3 shows carbon (C) / nitrogen (N) mole ratios of amine compounds analyzed by elemental analysis and X-ray photoelectron spectroscopy for amine-based carbon dioxide adsorbents. As a result, as the amount of epoxide used increased, the number of hydroxyalkyl groups functionalized on average in one amine increased, so it was confirmed that the C / N ratio increased in both the elemental analysis and the X-ray photoelectron spectroscopy. In addition, in the case of adsorbents prepared in the core-shell form, it was confirmed that the C / N ratio obtained through X-ray photoelectron spectroscopy was higher than the C / N ratio obtained by elemental analysis. This is because X-ray photoelectron spectroscopy selectively analyzes amine compounds present near the surface of the adsorbent, unlike elemental analysis that analyzes amine compounds distributed throughout the adsorbent, thereby allowing higher order amine compounds compared to the core amine compounds. It can be seen that the formed shell exists.

Example 3 Evaluation of carbon dioxide adsorption capacity of an amine-based carbon dioxide adsorbent having a core-shell structure and regeneration stability under temperature alternate adsorption conditions containing sulfur dioxide

The carbon dioxide adsorption capacity measurement and regeneration stability evaluation of the adsorbent prepared in Example 1 were performed in the following manner, and will be described in detail as follows with reference to FIGS. 4 and 5.

4 is 60 ℃, (15% CO ₂ , 5% H ₂ O, 80%) using an automatic catalyst characteristic analyzer (Autochem 2920, Micromeritics) equipped with a moisture trap and a thermal conductivity detector (TCD). N ₂ ) is a graph showing the adsorption amount of carbon dioxide in the adsorbent prepared in Example 1 over time. As the amount of the epoxide used to modify the amine compound increases, the average order of the amines increases, so it is confirmed that the adsorption performance decreases little by little. Therefore, it is important to form a shell of an appropriate thickness by using a minimum of epoxide in order to find an optimal adsorbent exhibiting high adsorption capacity and excellent regeneration stability.

5 is a graph showing carbon dioxide adsorption performance at 10 cycle intervals in a temperature shift adsorption experiment containing sulfur dioxide, which is a condition similar to an actual process condition, for the adsorbent prepared in Example 1. The adsorption / desorption conditions are as follows.

Adsorption conditions: 60 ℃ / 15% CO ₂ , 5% H ₂ O, 400 ppm SO ₂ balanced with N ₂

Desorption conditions: 110 ℃ / 100% CO ₂

In the case of the “10-EB-PEI / SiO ₂ ” adsorbent in which the sulfur dioxide resistant amine layer does not exist, it can be seen that the adsorption capacity gradually decreases as the adsorption / desorption cycle is repeated. This is because sulfur dioxide present in the gas during the adsorption process is irreversibly adsorbed to the amine compound, causing deactivation. However, in the case of core-shell type adsorbents having the sorbent as a core and having a higher order amine layer as a shell through an additional amine-epoxide reaction, it was confirmed that the regeneration stability was dramatically improved. This is due to the high sulfur dioxide resistance of the tertiary amine. In the adsorption process, the shell part having a high specific gravity of the tertiary amine selectively absorbs sulfur dioxide present in the gas to protect the amine compound in the core part, and in the desorption process, the shell part. This is because sulfur dioxide is effectively desorbed from and can be used to capture sulfur dioxide again in the next adsorption process. In the case of "10-1-EB-PEI / SiO ₂ " in which the amount of epoxide used to form the shell portion of the core-shell type adsorbents is relatively small, the amine compound of the core is effectively prevented from irreversible adsorption of sulfur dioxide. The tendency of the regeneration stability to be slightly lowered due to the lack of protection, but in the case of "10-1.5-EB-PEI / SiO ₂ " and "10-2-EB-PEI / SiO ₂ " adsorbents with higher amounts of epoxide It showed very high regeneration stability. Therefore, it was confirmed that the "10-1.5-EB-PEI / SiO ₂ " adsorbent is an optimal adsorbent having high regeneration stability and adsorption capacity.

As described above, specific parts of the present invention are described in detail, and it will be apparent to those skilled in the art that this specific technology is only a preferred embodiment, and the scope of the present invention is not limited thereby. will be. Accordingly, the substantial scope of the present invention will be defined by the appended claims and their equivalents.

Claims (17)

A core containing an amine compound and a porous carrier; And a shell containing a sulfur dioxide resistant amine compound coated around the core; and the proportion of nitrogen present as a tertiary amine among nitrogen atoms present in the sulfur dioxide resistant amine compound of the shell is 70% to 100% , The amine compound of the core includes a primary amine or a secondary amine and a tertiary amine, and the core-shell structure characterized in that the specific gravity of the primary amine or secondary amine is higher than that of the tertiary amine. Carbon dioxide adsorbent having a.
The carbon dioxide adsorbent according to claim 1, wherein the sulfur dioxide-resistant amine compound of the shell is an amine compound containing a hydroxy group-containing carbon chain.
The carbon dioxide adsorbent according to claim 1, wherein the sulfur dioxide-resistant amine compound of the shell is an amine compound represented by the following Chemical Formula 1.
[Formula 1]-[(CH ₂ ) _m (OH) _n NX] _y
(Wherein m is an integer from 1 to 20, n is an integer from 1 to 10, y is an integer from 1 to 100, X is hydrogen, alkyl having 1 to 18 carbons, cycloalkyl having 3 to 10 carbons, C1-C18 alkoxy, -CH = CH ₂ , -CH = CHCH ₂ CH ₃ , -CH ₂ CH = CHCH ₃ , -CH ₂ CH ₂ CH = CH ₂ , -CH = CHCH ₂ CH ₂ CH ₂ CH ₃ , -CH ₂ CH = CHCH ₂ CH ₂ CH ₃ , -CH ₂ CH ₂ CH = CHCH ₂ CH ₃ , -CH ₂ CH ₂ CH ₂ CH = CHCH ₃ , -CH ₂ CH ₂ CH ₂ CH ₂ CH = CH ₂ , -CH = CHCH ₂ CH ₂ CH ₂ CH ₂ CH ₂ CH ₃ , -CH ₂ CH = CHCH ₂ CH ₂ CH ₂ CH ₂ CH ₃ , -CH ₂ CH ₂ CH = CHCH ₂ CH ₂ CH ₂ CH ₃ ,- CH ₂ CH ₂ CH ₂ CH = CHCH ₂ CH ₂ CH ₃ , -CH ₂ CH ₂ CH ₂ CH ₂ CH = CHCH ₂ CH ₃ , -CH ₂ CH ₂ CH ₂ CH ₂ CH ₂ CH = CHCH ₃ , -CH ₂ CH ₂ CH ₂ CH ₂ CH ₂ CH ₂ CH = CH ₂ , -CH ₂ O (CH ₂ ) ₃ Si (OCH ₃ ) ₃ , -CH ₂ O (CH ₂ ) ₃ Si (OCH ₂ CH ₃ ) ₃ ,- CH ₂ O (CH ₂ ) ₂ CH ₃ , -CH ₂ O (CH ₂ ) ₃ CH ₃ , -CH ₂ OCH = CHCH ₃ , or -CH ₂ OCH ₂ CH = CH _2. )
delete The carbon dioxide adsorbent according to claim 1, wherein the sulfur dioxide-resistant amine compound of the shell contains 0.1% to 30% by weight based on the total amount of the adsorbent.
The carbon dioxide adsorbent according to claim 1, wherein the amine compound of the core comprises a unit skeleton structure represented by the following Chemical Formula 2 or 3.
[Formula 2]-[(CH ₂ ) _x -NR] _y
[Formula 3]-[(CH ₂ ) _x -NH ₂ ]
(In the above formula, R is hydrogen or hydrocarbon, x is an integer from 2 to 6, and y is an integer from 1 to 100.)
delete The carbon dioxide according to claim 1, wherein the amine compound of the core is an amine polymer or aminosilane modified with at least one of polyalkyleneimine and nitrogen atoms in the polyalkyleneimine polymer with a hydroxy group-containing carbon chain. absorbent.
9. The carbon dioxide adsorbent according to claim 8, wherein the polyalkyleneimine is polyethyleneimine or polypropyleneimine.
The method of claim 8, wherein the aminosilane is 3- (aminopropyl) trimethoxysilane, trimethoxy (3-methylaminopropylsilane), (N, N-dimethylaminopropyl) trimethoxysilane or N-. (3-Trimethoxysilylpropyl) Carbon dioxide adsorbent, characterized in that it is diethylenetriamine.
The carbon dioxide adsorbent according to claim 1, wherein the amine compound of the core contains 5% to 75% by weight based on the total amount of the adsorbent.
The carbon dioxide adsorbent according to claim 1, wherein the porous carrier of the core has a porosity of 0.1 cc / g to 5 cc / g.
The carbon dioxide adsorbent according to claim 1, wherein the porous carrier of the core contains 20% to 90% by weight relative to the total amount of the adsorbent.
Method for producing a carbon dioxide adsorbent having a core-shell structure of claim 1 comprising the following steps:
(a) immobilizing an amine compound on a porous carrier;
(b) adding a solution prepared by dissolving epoxide in a solvent to an amine compound immobilized on the carrier;
(c) The amine compound immobilized on the carrier is reacted with an epoxide to form a sulfur dioxide resistant amine layer, but the molar ratio of nitrogen atom: epoxide present in the amine compound immobilized on the carrier is 1: 0.2 to 1: 1; And
(d) removing the solvent to obtain a carbon dioxide adsorbent containing a sulfur dioxide resistant amine layer.
delete The method of claim 14, wherein the epoxide is composed of 1,2-epoxyethane, 1,2-epoxypropane, 1,2-epoxybutane, 1,2-epoxypentane and 1,2-epoxyhexane. Method for producing a carbon dioxide adsorbent, characterized in that at least one selected from the group.
Carbon dioxide adsorption method using the adsorbent according to any one of claims 1 to 3, 5, 6 and 8 to 13.

Images