KR20180045956A - Method and appratus for separating carbon dioxide from gas mixture - Google Patents

Abstract

According to the present invention, provided is a method for separating carbon dioxide from mixed gas, which comprises the steps of: (a) allowing carbon dioxide (CO_2) to be in contact with an absorbent to produce a final absorbent in which CO_2 is absorbed; (b) separating a part or all of CO_2 from the final absorbent to prepare a recirculation absorbent; (c) preparing a saturable absorbent, in which CO_2 is re-absorbed, by allowing the recirculation absorbent to be in contact with mixed gas including CO_2; and (d) separating CO_2 from the saturable absorbent and regenerating the saturated absorbent. Accordingly, the plugging or fouling of a pipe or the like can be reduced.

Description

Field of the Invention [0001] The present invention relates to a method and apparatus for separating carbon dioxide from a gas mixture,

The present invention relates to a method and an apparatus for separating carbon dioxide from a gas mixture, and more particularly, to a method and apparatus for separating carbon dioxide gas from a gas mixture, ≪ / RTI >

As a result of man-made activities, global warming is under way due to the increase in greenhouse gas concentrations such as carbon dioxide in the atmosphere. Carbon dioxide contributes more than 60% to global warming due to a considerable amount of CO2 emissions compared to other greenhouse gases. In order to reduce the atmospheric release of carbon dioxide, carbon dioxide capture and storage technology is being actively studied as a method for selectively separating and isolating carbon dioxide generated in a power plant, a steel mill, and a cement industry. Particularly, as a method for selectively separating only carbon dioxide from the exhaust gas, there is a method of seawater cooling, membrane separation, absorption, adsorption and the like.

CO2 emission sources are coal, oil, natural gas, thermal power plant, steel mill, and cement industry. In addition, a large amount of carbon dioxide is emitted from the anaerobic fermentation even in waste landfill and sewage treatment plant.

It is possible to use a packed tower or membrane contactor which is equipped with an absorbent to remove carbon dioxide. The membrane contactor has a larger surface area of gas-liquid contact than the packed tower, have. Therefore, a membrane contactor to which a polymer membrane such as polypropylene is applied is actively studied as a carbon dioxide capture technique.

However, it is a typical obstacle to commercialization that there is a membrane wetting phenomenon in which the absorbent solution wets the pores of the membrane when used for a long period of time. As a result, there has been a problem in that time and cost are further added to remove water or replace the membrane.

It is also preferred that the absorbent for separating carbon dioxide from the mixed gas is produced at a high concentration because it can reduce the load of the liquid pump by increasing the amount of carbon dioxide that can be removed per cycle. Solid particles or precipitates may be generated when the aqueous solution of the absorbent is produced at a high concentration of 30 wt% or more, thereby causing plugging (plugging) and fouling (contamination) in piping and filling materials in the process of removing carbon dioxide.

It is an object of the present invention to provide a carbon dioxide separation method capable of using an absorbent capable of minimizing film wettability when applying carbon dioxide to a membrane contactor by increasing the surface tension of the absorbent while performing carbon dioxide removal more efficiently than conventional absorbents .

Another object of the present invention is to provide a carbon dioxide separating apparatus which can perform carbon dioxide removal more efficiently than conventional absorbents, and which can utilize an absorbent capable of minimizing membrane wetting when applied to a membrane contactor by increasing the surface tension of the absorbent, And a separating device.

Another object of the present invention is to increase the solubility of a precipitate of an amine or a salt present in an absorbent to remove particulate matter in the absorbent to remove plugging of the absorbent column or absorption of carbon dioxide which can reduce fouling A method and a separation device.

According to an aspect of the present invention, there is provided a method for producing a final absorbent comprising: (a) contacting an absorbent with carbon dioxide (CO ₂ ) to produce a final absorbent having absorbed CO ₂ ; (b) separating part or all of CO ₂ from the final absorbent to produce a recycled absorbent; (c) contacting said recirculating absorbent with a gas mixture containing the CO ₂ producing a saturated CO ₂ absorbent of the absorbing material; And (d) separating CO ₂ from the saturated absorbent and regenerating the saturated absorbent, wherein the carbon dioxide is separated from the mixed gas.

Wherein step (a) comprises the steps of: (a-1) contacting carbon dioxide (CO ₂ ) or a mixture of CO ₂ and an inert gas with an absorbent to absorb CO ₂ to produce a pretreated absorbent; And (a-2) separating a part of CO ₂ from the pretreated absorbent to prepare a final absorbent.

In addition, step (a) may be a step of contacting carbon dioxide (CO ₂ ) or a mixture of CO ₂ and an inert gas with an absorbent to dissolve CO ₂ to produce a final absorbent in which the precipitate or solid particles have been removed.

Further, the absorbent may comprise at least one selected from the group consisting of amino acids and amino acid salts (A); And

(B) at least one selected from the group consisting of primary amine, secondary amine and tertiary amine, and at least one selected from the group consisting of potassium carbonate, sodium carbonate, sodium bicarbonate, potassium hydroxide and sodium hydroxide; And water (C); . ≪ / RTI >

Further, the absorbent may be at least one selected from amino acids and amino acid salts; At least one amine selected from primary amines, secondary amines and tertiary amines; And water.

And wherein the absorbent is at least one selected from the group consisting of amino acids and amino acid salts; Potassium carbonate, sodium carbonate, sodium bicarbonate, potassium hydroxide and sodium hydroxide; And water.

The amino acid salt may be a salt of one or more amino acids selected from potassium hydroxide, sodium hydroxide and lithium hydroxide.

The ratio (M1: M2) of the molar concentration (M1) of the amine or potassium salt or sodium salt to the molar concentration (M2) of the amino acid or amino acid salt in the aqueous solution may be 1: 0.01 to 1:10.

The ratio (M1: M2) of the molar concentration (M1) of the amine or potassium salt or the sodium salt to the molar concentration (M2) of the amino acid or amino acid salt in the aqueous solution may be 1: 0.1 to 1: 1.

The ratio (M1: M2) of the molar concentration (M1) of the amine or potassium salt or sodium salt to the molar concentration (M2) of the amino acid or amino acid salt in the aqueous solution may be 1: 0.4.

(A) at least one selected from amino acids and amino acid salts; And at least one selected from the group consisting of primary amine, secondary amine and tertiary amine, and at least one selected from the group consisting of potassium carbonate, sodium carbonate, sodium bicarbonate, potassium hydroxide and sodium hydroxide; (A + B) / (A + B + C)) x 100) of 5 to 70 wt%.

The concentration (((A + B) / (A + B + C)) x 100) in the aqueous solution may be 20 to 50% by weight.

Also, the concentration (((A + B) / (A + B + C)) x 100) in the aqueous solution may be 30 to 45% by weight.

Further, the surface tension of the absorbent may have a value larger than 70 mN / m.

The amino acid may be at least one selected from glycine, alanine, serine, cysteine, taurine, gamma aminobutyric acid, arginine and histidine.

The amine may be at least one selected from monoamines, polyamines containing two or more amine groups, and cyclic amines.

Also, the amine may be selected from the group consisting of piperazine (PZ), 2-amino-2-hydroxymethyl-1,3-propanediol (AHPD) 2-methyl-1,3-propanediol, AMPD, 2-aminomethyl-1,3-propanol, 2-hydroxymethyl-1,3-propanediol, 2-amino-1,1,1-ethanetriol, hydrazine, ethylenediamine, diethylenetriamine , Triethylenetetraamine, tetraethylenepentamine, monoethanolamine, diethanolamine, triethanolamine, and N-methyldiethanolamine.

According to another aspect of the present invention, there is provided an absorbent treatment tower for contacting a carbon dioxide (CO ₂ ) to an absorbent to produce a final absorbent having CO ₂ absorbed therein; A step of supplying the final absorbent from the absorbent treatment tower and separating a part or all of CO ₂ from the final absorbent to prepare a recirculating absorbent, or a method of separating CO ₂ by supplying a saturated absorbent from the absorption tower, tower; And an absorption tower that receives supplies the recirculating absorbent, into contact with the recirculating absorbent with a gas mixture containing the CO ₂ absorbed material to CO ₂ in the recirculating absorber production of the saturated absorbent from the regeneration column; in a mixed gas containing the A carbon dioxide separation device for separating carbon dioxide is provided.

Further, the carbon dioxide separator may further include a heat exchanger for lowering the temperature of the recycle absorbent discharged from the regeneration tower and supplied to the absorption tower, or for increasing the temperature of the saturated absorbent discharged from the absorption tower and supplied to the regeneration tower You can include,

Further, the carbon dioxide separation device may include a concentration meter for measuring the CO ₂ concentration of the absorbent in the absorbent treatment tower.

In addition, the carbon dioxide separator may include a concentration meter for measuring the CO ₂ concentration of the exhaust gas of the regeneration tower.

In addition, the carbon dioxide separation device may include a concentration measuring device for measuring the CO ₂ concentration of the exhaust gas of the absorption tower.

The present invention relates to a method for removing carbon dioxide by using an absorbent that can remove carbon dioxide more effectively than conventional absorbents when separating carbon dioxide from the mixed gas, while minimizing membrane wetting when applied to a membrane contactor by increasing the surface tension of the absorbent. It is possible to provide a carbon dioxide separation method which can be effectively performed.

The present invention relates to a carbon dioxide separator which can remove carbon dioxide from a gas mixture more efficiently than a conventional carbon dioxide separator but also can be used for a carbon dioxide separator by using an absorbent that can minimize film wettability when applied to a membrane contactor, It is possible to provide a carbon dioxide separation device capable of efficiently removing carbon dioxide.

The present invention relates to a method and apparatus for separating carbon dioxide, which can reduce plugging or fouling of a membrane contactor, a pipe or the like, which is an absorption tower, by removing particulate matter in the absorbent by increasing the solubility of the amine or salt precipitate present in the absorbent. Device can be provided.

1 is a schematic view schematically showing a carbon dioxide separation apparatus of the present invention.
2 is a photograph of a membrane contactor used as an absorber in the carbon dioxide separation apparatus of the present invention.
3 is a schematic view showing a carbon dioxide separation apparatus of a comparative example.
4 is a photograph of the absorbent of the present invention and the absorbent after bubbling CO ₂ at room temperature.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily carry out the present invention.

However, the following description does not limit the present invention to specific embodiments. In the following description of the present invention, detailed description of related arts will be omitted if it is determined that the gist of the present invention may be blurred .

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The singular expressions include plural expressions unless the context clearly dictates otherwise. In the present application, the terms " comprises ", or " having ", and the like, specify that the presence of stated features, integers, steps, operations, elements, or combinations thereof, But do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, or combinations thereof.

Hereinafter, a method for separating carbon dioxide from the mixed gas of the present invention will be described.

Step (a): Preparation of final absorbent

Carbon dioxide (CO ₂ ) is brought into contact with the absorbent to prepare a final absorbent having absorbed CO ₂

Step (a) the end-absorbing agent to remove a portion of the CO ₂ in the carbon dioxide (CO ₂₎ or by contacting a mixture of CO ₂ and inert gas to the absorber manufacturing the pre-absorber to absorb the CO ₂ or the pre-absorbent in Can be manufactured.

Further, in step (a), a mixture of carbon dioxide (CO ₂ ) or CO ₂ and an inert gas may be contacted with an absorbent to dissolve CO ₂ to produce a final absorbent in which the precipitate or solid particles have been removed.

Further, the absorbent may comprise at least one selected from the group consisting of amino acids and amino acid salts (A); (B) at least one selected from the group consisting of primary amine, secondary amine and tertiary amine, and at least one selected from the group consisting of potassium carbonate, sodium carbonate, sodium bicarbonate, potassium hydroxide and sodium hydroxide; And water (C).

And wherein the absorbent is at least one selected from the group consisting of amino acids and amino acid salts; At least one amine selected from primary amines, secondary amines and tertiary amines; And water.

And wherein the absorbent is at least one selected from the group consisting of amino acids and amino acid salts; Potassium carbonate, sodium carbonate, sodium bicarbonate, potassium hydroxide and sodium hydroxide; And water.

The amino acid salt may be a salt of one or more amino acids selected from potassium hydroxide, sodium hydroxide and lithium hydroxide.

The ratio (M1: M2) of the molar concentration (M1) of the amine or potassium salt or sodium salt to the molar concentration (M2) of the amino acid or amino acid salt in the aqueous solution is 1: 0.01 to 1:10, 0.1 to 1: 1, more preferably 1: 0.4.

At least one (A) selected from the group consisting of amino acids and amino acid salts in the aqueous solution; And at least one selected from the group consisting of primary amine, secondary amine and tertiary amine, and at least one selected from the group consisting of potassium carbonate, sodium carbonate, sodium bicarbonate, potassium hydroxide and sodium hydroxide; (A + B) / (A + B + C)) x 100) of 5 to 70 wt%, preferably 20 to 50 wt%, more preferably 30 to 45 wt% %. ≪ / RTI >

Further, the surface tension of the absorbent may have a value larger than 70 mN / m.

The amino acid may be at least one selected from glycine, alanine, serine, cysteine, taurine, gamma aminobutyric acid, arginine and histidine.

The amine may be at least one selected from the group consisting of a monoalkanol amine, a polyamine including an amine group in which one or two hydrogen atoms are substituted, and a cyclic amine.

Also, the amine may be selected from the group consisting of piperazine (PZ), 2-amino-2-hydroxymethyl-1,3-propanediol (AHPD) 2-methyl-1,3-propanediol, AMPD, 2-aminomethyl-1,3-propanol, 2-hydroxymethyl-1,3-propanediol, 2-amino-1,1,1-ethanetriol, hydrazine, ethylenediamine, diethylenetriamine , Triethylenetetraamine, tetraethylenepentamine, monoethanolamine, diethanolamine, triethanolamine, and N-methyldiethanolamine.

Step (b): Preparation of recycled absorbent

A part or all of CO ₂ in the final absorbent may be separated to prepare a recycled absorbent.

Step (c): Preparation of a saturated absorbent

The recycled absorbent is contacted with a mixed gas containing CO ₂ to produce a saturated absorbent in which CO ₂ is reabsorbed.

Step (d) CO ₂ And regenerate the saturated absorbent

It is possible to separate CO ₂ from the saturated absorbent and regenerate the saturated absorbent.

Next, the carbon dioxide separation apparatus 10 of the present invention will be described with reference to Fig.

The carbon dioxide separation apparatus 10 of the present invention may include an absorbent treatment tower 100.

In the absorbent treatment tower 100, carbon dioxide (CO ₂ ) or a mixture Fa of CO ₂ and an inert gas may be contacted with the absorbent (Fb) to produce a final absorbent (Fc) in which CO ₂ has been absorbed.

The carbon dioxide separation apparatus 10 of the present invention may include a regeneration tower 200.

In the regeneration tower 200, the final absorbent Fc is supplied from the absorbent treatment tower 100 and a part or all of CO ₂ is separated from the final absorbent Fc to produce a recycled absorbent F 4. have.

Alternatively, in the regeneration tower 200, the saturated absorbent F2 may be supplied from the absorption tower 300 to separate CO ₂ and regenerate the saturated absorbent.

The carbon dioxide separation apparatus 10 of the present invention may include an absorption tower 300.

Being supplied to the recirculating absorber (F4) from the regeneration column (200), is contacted with a gas mixture (F1) contained the recycled CO ₂ absorbent can be recycled for re-absorption of CO ₂ absorber (F4). The mixed gas F1 may be a waste gas containing CO ₂ generated from a steel mill, a thermal power plant, a landfill gas, or the like.

The carbon dioxide separation apparatus 10 of the present invention may further include a heat exchanger 500.

In the heat exchanger 500, the temperature of the recycled absorbent F 4 discharged from the regeneration tower 200 and supplied to the absorption tower 300 can be lowered. Alternatively, in the heat exchanger 500, the temperature of the saturated final absorbent F 2 discharged from the absorption tower 300 and supplied to the regeneration tower 200 can be increased.

The carbon dioxide separation device 10 may include a concentration measuring device 210 for measuring the CO ₂ concentration of the absorbent in the absorbent treatment tower 100 on the absorbent treatment tower 100.

In addition, the carbon dioxide separator 10 may include a concentration measuring device on the regeneration tower 200 for measuring the CO ₂ concentration of the exhaust gas of the regeneration tower 200.

The carbon dioxide separator 10 may include a concentration meter 270 on the absorption tower 300 for measuring the CO ₂ concentration of the exhaust gas of the absorption tower 300.

[Example]

Example  One

Preparation of pretreatment absorbent

Referring to FIG. 1, at a room temperature, 5 L of an absorbent (Fb) was prepared at a concentration of 2.5 M piperazine (PZ) and 1.0 M potassium serinate (K-Ser) and injected into an absorbent treatment tower 100 at 40 ° C. Since the amino acid is cationized in the aqueous solution when the amino acid is added, the equimolar KOH is slowly added to neutralize it, and the cationized amino acid is neutralized and added.

The mixture (Fa) with a volume ratio of CO ₂ : N ₂ = 15%: 85% was prepared using a mass flow controller and the CO ₂ flow rate was bubbled into the absorbent at a flow rate of 10 L / min. The concentration of CO ₂ discharged from the rear end of the absorbent treatment tower 100 was measured using the real time gas analyzer 210. If the concentration of CO ₂ to reach the 14.8% was prepared in the pre-absorber and terminate the CO ₂ absorption.

Preparation of final absorbent

When the temperature of the treatment tower was raised to 80 ° C to prepare the residual absorbent that was manufactured in the treatment tower 100 as a final absorbent, nitrogen at the same flow rate as that in the pretreatment was injected into the pretreatment absorbent to remove CO ₂ was removed. When the concentration of CO ₂ measured by the real-time gas analyzer 210 reached 1%, the elimination reaction was terminated to prepare a final absorbent (Fc) ready for use in the actual process.

CO ₂  Resorption

CO ₂ stripping and finally the final absorber (Fc) obtained after after introduced into regeneration column heat exchanger (500) passes through after the temperature has been around 60 ℃ circulated in CO ₂ absorber 300 of 40 ℃ CO ₂ uptake . This recycled absorbent F4 can be said to be the absorbent F4 in the actual CO ₂ separation process.

Recycled sorbent (F4) prepared for CO ₂ reabsorption was injected at a flow rate of 62 ml / min into the lumen side of the hollow fiber membrane contactor, absorption tower 300 shown in FIG. The CO ₂ reabsorption was carried out by injecting a mixed gas (F1) of CO ₂ : N ₂ = 15%: 85% by volume on the shell side of the absorption tower 300 at a flow rate of 36 ml / min based on the CO ₂ flow rate.

CO ₂ detach

Referring to FIG. 1, the CO ₂ saturated absorbent F ₂ is heated to 120 ° C. in the regeneration tower 200 after passing through the heat exchanger 500, thereby separating CO ₂ from the thermal energy and regenerating the absorbent. The recycled absorbent F4 separated and regenerated CO ₂ was again introduced to the top of the absorption tower after passing through the heat exchanger 500.

Example  2

(Fb) at room temperature instead of injecting 5 L of sorbent (Fb) at room temperature into 2.5 M piperazine (PZ) and 1.0 M potassium serinate (K-Ser) 5 L of monoethanolamine (MEA) was prepared at a concentration of 5.0 M and injected into the absorbent treatment tower 100 at 40 ° C.

Comparative Example  One

5 L of an absorbent (Fb ') aqueous solution of 2.5 M piperazine (PZ) and 1.0 M potassium serinate (K-Ser) was prepared at room temperature without pretreatment with the same absorbent as in Example 1. 3, an absorbent (Fb ') is injected into the lumen side of the hollow fiber membrane contactor, which is an absorption tower, at a flow rate of 62 ml / min on top of a CO ₂ absorption tower 300' at 60 ° C. However, when 2.5 M piperazine (PZ) and 1.0 M potassium serinate (K-Ser) were prepared at room temperature, the precipitate was not dissolved and stirred at 80 ° C for 2 hours with stirring. Was introduced into the absorption tower 300 '. The CO ₂ absorption was performed by injecting a mixed gas (F1 ') of CO ₂ : N ₂ = 15%: 85% by volume on the shell side of the absorption tower 300' at a flow rate of 36 ml / min based on the CO ₂ flow rate.

CO ₂ saturated absorbent that has absorbed the CO ₂ (F2 ') is a heat exchanger (500' and the CO ₂ separation due to thermal energy, the liquid feed to the regeneration column (200 regeneration column 200, via a) by heating in) to 120 ℃ Regeneration of the absorbent was achieved. The CO ₂ recovered recycled absorbent F4 'was again introduced to the top of the absorption tower 300' after passing through the heat exchanger 500 '.

Comparative Example  2

(Fb ') which is an aqueous solution of monoethanolamine (MEA) at a concentration of 5.0 M was used instead of the absorbent (Fb') which was an aqueous solution of 2.5 M piperazine (PZ) and 1.0 M potassium serinate Was carried out in the same manner as in Comparative Example 1.

[Test Example]

Test Example  1: CO ₂  Removal rate

The sorbent was prepared by calculating the amount of sorbent required for the membrane contactor experiment for CO ₂ reabsorption. The specifications of the membrane contactor for testing the performance of the absorbent are shown in Table 1 and the photograph of the membrane contactor is shown in FIG. The CO ₂ removal rate after 5 minutes from the time when the recycled absorbent was introduced into the absorption tower was calculated by the following formula 1 and is shown in Table 2 below.

[Equation 1]

CO ₂ removal rate (%) = ((C ₁ -C ₂ ) / C ₁ ) × 100

In the above equation 1, C ₁ is the CO ₂ concentration in the mixed gas introduced into the shell side of the membrane contactor, and C ₂ is the concentration of CO ₂ in the exhaust gas discharged from the membrane contactor.

Kinds value Hollow Fiber Outside Diameter (μm) 840 Diameter of hollow fiber (μm) 600 Fiber porosity (%) 67 Fiber length (mm) 270 Number of hollow fibers 100 Average pore size (μm) 0.15 Module packing density (%) 45

As shown in Table 2, CO ₂ was partially absorbed through the treatment tower under the same conditions, and the pretreated absorbent showed a CO ₂ removal rate of about 5% higher than that of the non-absorbent under the same conditions.

Kinds Absorbent Whether preprocessing CO ₂ Removal Rate (%) Comparative Example 1 2.5 M PZ + 1.0 K-Ser X 86.7 Comparative Example 2 5.0 M MEA X 76.3 Example 1 2.5 M PZ + 1.0 K-Ser ○ 91.3 Example 2 5.0 M MEA ○ 81.8

Test Example  2: Comparison of transparency of absorbent

4, the turbidity of absorbent (left) prepared at normal temperature and absorbent (right) (absorbent: 2.5 M piperazine (PZ) + 1.0 M potassium serinate (K-Ser)) bubbling CO ₂ at room temperature And observed with naked eyes. It was observed that the sediment was generated in 2.5 M piperazine (PZ) + 1.0 M potassium serinate (K-Ser) at room temperature, but the precipitate disappeared and the solution became transparent during the pretreatment of CO ₂ bubbling in the treatment column. For reference, when the absorbent was heated to 40 ° C, the precipitate was not removed by stirring, and when the solution was heated to 80 ° C, the precipitate was removed.

Test Example  3: Surface tension

The surface tension of CO ₂ lean was measured at 25 ℃ using Kruss' BP2 model after absorbing CO ₂ through pretreatment in absorber that did not absorb CO ₂ and treatment tower.

As shown in Table 3, when CO ₂ was bubbled in the case of 2.5 M PZ + 1.0 M K-Ser solution, the surface tension was increased by 1.9 mN / m at 25 ° C in the presence of a certain amount of CO ₂ in the absorbent, The membrane wetting phenomenon was expected to be reduced due to the higher surface tension than the% MEA.

Absorbent Surface tension (mN / m) 30 wt% (= 5.0M) MEA (fresh solution) 68.2 2.5 M PZ + 1.0 M K-Ser (fresh solution) 72.0 2.5 M PZ + 1.0 M K-Ser (CO ₂ lean solution) 73.9

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims. For example, each component described as a single entity may be distributed and implemented, and components described as being distributed may also be implemented in a combined form. The scope of the present invention is defined by the appended claims rather than the detailed description and all changes or modifications derived from the meaning and scope of the claims and their equivalents are to be construed as being included within the scope of the present invention do.

Claims (20)

(a) contacting the absorbent with carbon dioxide (CO ₂ ) to produce a final absorbent in which CO ₂ has been absorbed;
(b) separating part or all of CO ₂ from the final absorbent to produce a recycled absorbent; And
a; (c) the step of contacting said recirculating absorbent with a gas mixture containing the CO ₂ producing a saturated CO ₂ absorbent of the absorbing material
(d) separating CO ₂ from the saturated absorbent and regenerating the saturated absorbent;
A method for separating carbon dioxide from a mixed gas comprising. The method according to claim 1,
If step (a)
(a-1) contacting carbon dioxide (CO ₂ ) or a mixture of CO ₂ and an inert gas with an absorbent to absorb CO ₂ to prepare a pretreated absorbent; And
(a-2) separating a portion of CO ₂ from the pretreated absorbent to produce a final absorbent. The method according to claim 1,
Wherein step (a) is a step of contacting carbon dioxide (CO ₂ ) or a mixture of CO ₂ and an inert gas with an absorbent to dissolve CO ₂ to produce a final absorbent in which precipitates or solid particles have been removed. In the mixed gas, / RTI > The method according to claim 1,
The absorbent
At least one (A) selected from amino acids and amino acid salts;
(B) at least one selected from the group consisting of primary amine, secondary amine and tertiary amine, and at least one selected from the group consisting of potassium carbonate, sodium carbonate, sodium bicarbonate, potassium hydroxide and sodium hydroxide; And
Water (C); of
≪ / RTI > wherein the carbon dioxide is an aqueous solution containing carbon dioxide. 5. The method of claim 4,
Wherein the amino acid salt is a salt of at least one amino acid selected from potassium hydroxide, sodium hydroxide and lithium hydroxide, and separating the carbon dioxide from the mixed gas. 5. The method of claim 4,
Wherein the ratio (M1: M2) of the molar concentration (M1) of the amine to the molar concentration (M2) of the amino acid or amino acid salt in the aqueous solution is 1: 0.01 to 1:10. . The method according to claim 6,
Wherein the ratio (M1: M2) of the molar concentration (M1) of the amine to the molar concentration (M2) of the amino acid or amino acid salt in the aqueous solution is 1: 0.1 to 1: . 8. The method of claim 7,
Wherein the ratio (M1: M2) of the molar concentration (M1) of the amine to the molar concentration (M2) of the amino acid or amino acid salt in the aqueous solution is 1: 0.4. 5. The method of claim 4,
In the aqueous solution
At least one (A) selected from amino acids and amino acid salts; And at least one selected from the group consisting of primary amine, secondary amine and tertiary amine, and at least one selected from the group consisting of potassium carbonate, sodium carbonate, sodium bicarbonate, potassium hydroxide and sodium hydroxide; (A + B) / (A + B + C)) x 100) of from 5 to 70% by weight based on the total weight of the mixed gas. 10. The method of claim 9,
Wherein the concentration (((A + B) / (A + B + C)) x 100) in the aqueous solution is 20 to 50 wt%. 11. The method of claim 10,
Wherein the concentration (((A + B) / (A + B + C)) x 100) in the aqueous solution is 30 to 45% by weight. The method according to claim 1,
Wherein the surface tension of the absorbent has a value greater than 70 mN / m. The method according to claim 1,
Wherein the amino acid is at least one selected from glycine, alanine, serine, cysteine, taurine, gammaaminobutyric acid arginine, and histidine. The method according to claim 1,
Wherein the amine is at least one selected from the group consisting of monoamines, polyamines containing two or more amine groups, and cyclic amines. The method according to claim 1,
Wherein the amine is selected from the group consisting of piperazine (PZ), 2-amino-2-hydroxymethyl-1,3-propanediol (AHPD) 2-amino-2-methyl-1,3-propanediol, AMPD, 2-aminomethyl-2- hydroxymethyl-1,3-propanediol, 2-amino-1,1,1-ethanetriol, hydrazine, ethylenediamine, diethylenetriamine, tri Wherein the carbon dioxide is at least one selected from the group consisting of ethylene tetraamine, tetraethylene pentaamine, monoethanolamine, diethanolamine, triethanolamine and N-methyldiethanolamine. An absorbent treatment tower for contacting the absorbent with carbon dioxide (CO ₂ ) to produce a final absorbent having absorbed CO ₂ ;
A step of supplying the final absorbent from the absorbent treatment tower and separating a part or all of CO ₂ from the final absorbent to prepare a recirculating absorbent, or a method of separating CO ₂ by supplying a saturated absorbent from the absorption tower, tower; And
Being supplied to the recirculated absorbent from the regeneration column, it contacting said recirculating absorbent with a gas mixture containing the CO ₂ absorbed by the material recycled to the CO ₂ absorber absorber for preparing the saturated absorbent; of
A carbon dioxide separation device for separating carbon dioxide from a mixed gas comprising. 17. The method of claim 16,
The carbon dioxide separation device
Further comprising a heat exchanger for lowering the temperature of the recycle absorbent discharged from the regeneration tower and supplied to the absorption tower or for increasing the temperature of the saturated absorbent discharged from the absorption tower and supplied to the regeneration tower, Separating device. 17. The method of claim 16,
Wherein the carbon dioxide separator comprises a concentration meter for measuring the CO ₂ concentration of the absorbent in the absorbent treatment tower. 17. The method of claim 16,
Wherein the carbon dioxide separator comprises a concentration meter for measuring the CO ₂ concentration of the exhaust gas of the regeneration tower. 17. The method of claim 16,
Wherein the carbon dioxide separation device includes a concentration meter for measuring the CO ₂ concentration of the exhaust gas of the absorption tower.

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