KR102069099B1 - Absorbent for separating carbon dioxide from gas mixture - Google Patents

Abstract

The present invention comprises the steps of (a) contacting the absorbent with carbon dioxide (CO ₂ ) to prepare a final absorber absorbed by CO ₂ ; (b) preparing a recycled absorbent by separating some or all of the CO ₂ from the final 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.

Description

ABSORBENT FOR SEPARATING CARBON DIOXIDE FROM GAS MIXTURE}

The present invention relates to a method and apparatus for separating carbon dioxide from a mixed gas, and more particularly, a method for separating carbon dioxide from a mixed gas capable of minimizing film wetting when applied to a membrane contactor by increasing the surface tension of the absorbent and Relates to a device.

Global warming is underway as a result of human activity and due to increasing concentrations of greenhouse gases such as carbon dioxide in the atmosphere. CO2 contributes more than 60% to global warming because it generates significantly more than other greenhouse gases. CO2 capture and storage technologies are being actively researched as a method for selectively separating and sequestering carbon dioxide generated in power plants, steel mills, and cement industries to reduce carbon dioxide emissions into the atmosphere. In particular, methods for selectively separating only carbon dioxide from exhaust gas include deep cooling, membrane separation, absorption, and adsorption.

The main sources of CO2 emissions are coal-fired power plants, steel mills, and cement industries that use coal, oil, and natural gas. In addition, waste landfills and sewage treatment plants emit carbon dioxide due to anaerobic fermentation.

Packed towers or membrane contactors can be used as devices to remove carbon dioxide by including absorbents. Membrane contactors have a large gas-liquid contact specific surface area compared to packed towers, so the size of the device can be reduced, which can be supplied to small businesses. have. Therefore, a membrane contactor to which a polymer film such as polypropylene is applied has been actively studied as a carbon dioxide capture technology.

However, the major obstacle to commercialization is the membrane wetting phenomenon, in which the absorbent solution wets the pores of the membrane during long-term use. As a result, there was a problem in that additional time and money were added to remove moisture or replace the membrane.

In addition, absorbents for the separation of carbon dioxide from mixed gases are preferred because high concentrations can reduce the load on the liquid pump by increasing the amount of CO2 removed per cycle. For example, solid particles or precipitates may occur when the aqueous solution of the absorbent is produced at a high concentration of 30 wt% or more, thereby causing plugging (blocking) and fouling (contamination) in pipes, fillings, etc., when the carbon dioxide is removed.

An object of the present invention is to provide a carbon dioxide separation method that can use the absorbent which can minimize the film wetting phenomenon when applied to the membrane contactor by increasing the surface tension of the absorbent while performing carbon dioxide removal more efficiently than the conventional absorbent during carbon dioxide separation. To provide.

Another object of the present invention is to improve the surface tension of the absorbent while applying carbon dioxide removal more efficiently than when applied to the carbon dioxide separation device, carbon dioxide that can use the absorbent to minimize the film wetting phenomenon when applied to the membrane contactor It is to provide a separation device.

Another object of the present invention is to increase the solubility of the precipitates of amines or salts present in the absorbent to remove particulate matter in the absorbent to reduce plugging or fouling of the membrane contactor, pipe, etc., which is an absorption tower. A method and a separator are provided.

According to one aspect of the invention, (a) contacting the absorbent with carbon dioxide (CO ₂ ) to prepare a final absorber absorbed by CO ₂ ; (b) preparing a recycled absorbent by separating some or all of the CO ₂ from the final 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 step (a) comprises (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) preparing a final absorbent by separating a portion of the CO ₂ from the pretreated absorbent.

Also, step (a) may be a step of preparing a final absorbent in which carbon dioxide (CO ₂ ) or a mixture of CO ₂ and an inert gas is contacted with an absorbent to dissolve CO ₂ to remove precipitates or solid particles.

In addition, the absorbent is one or more selected from amino acids and amino acid salts (A); And

At least one selected from primary amines, secondary amines and tertiary amines; and at least one selected from potassium carbonate, sodium carbonate, sodium bicarbonate, potassium hydroxide and sodium hydroxide: at least one selected from (B); And water (C); It may include.

In addition, the absorbent is one or more selected from amino acids and amino acid salts; At least one amine selected from primary amines, secondary amines and tertiary amines; And water :.

In addition, the absorbent is one or more selected from amino acids and amino acid salts; Potassium carbonate, sodium carbonate, sodium bicarbonate, potassium hydroxide and sodium hydroxide; And water :.

In addition, the amino acid salt may be a salt of an amino acid and at least one selected from potassium hydroxide, sodium hydroxide and lithium hydroxide.

In addition, a ratio (M1: M2) of the molarity (M1) of the amine or potassium salt or sodium salt and the molarity (M2) of the amino acid or amino acid salt in the aqueous solution may be 1: 0.01 to 1:10.

In addition, a ratio (M1: M2) of the molarity (M1) of the amine or potassium salt or sodium salt and the molarity (M2) of the amino acid or amino acid salt in the aqueous solution may be 1: 0.1 to 1: 1.

In addition, a ratio (M1: M2) of the molarity (M1) of the amine or potassium salt or sodium salt and the molarity (M2) of the amino acid or amino acid salt in the aqueous solution may be 1: 0.4.

And at least one selected from amino acids and amino acid salts (A); And at least one selected from primary amines, secondary amines and tertiary amines; and at least one selected from potassium carbonate, sodium carbonate, sodium bicarbonate, potassium hydroxide and sodium hydroxide: at least one selected from (B); The weight percent concentration (((A + B) / (A + B + C)) × 100) of A + B) may be between 5 and 70 wt%.

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

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

In addition, the surface tension of the absorbent may have a value greater than 70 mN / m.

In addition, the amino acid may be at least one selected from glycine, alanine, serine, cysteine, taurine, gammaaminobutyric acid, arginine and histidine.

In addition, the amine may be at least one selected from a monoamine, a polyamine containing two or more amine groups, and a cyclic amine.

In addition, the amine is piperazine (piperazine, PZ), 2-amino-2-hydroxymethyl-1,3-propanediol (2-amino-2-hydroxymethyl-1,3-propanediol, AHPD), 2-amino 2-methyl-1,3-propanediol (2-amino-2-methyl-1,3-propanediol, AMPD), 2-aminomethyl-2-hydroxymethyl-1,3-propanol (2-aminomethyl- 2-hydroxymethyl-1,3-propanediol), 2-amino-1,1,1-ethanetriol, hydrazine, ethylenediamine, diethylenetriamine , Triethylenetetraamine, tetraethylenepentaamine, monoethanolamine, diethanolamine, triethanolamine and N-methyldiethanolamine.

According to another aspect of the invention, the absorbent treatment tower for producing a final absorbent absorbed by the carbon dioxide (CO ₂ ) to the absorbent to absorb the CO ₂ ; Reproduction to being supplied to the final absorber reproducing saturated sorbent and to remove the CO ₂ received disconnect any or all of the CO ₂ to produce a recirculating absorbent, or supplying the saturated absorbent from the absorber in the final sorbent from the sorbent processing 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 separator is provided for separating carbon dioxide.

In addition, the heat exchanger for reducing the temperature of the recirculating absorbent discharged from the regeneration tower and supplied to the absorption tower or the temperature of the saturated absorbent discharged from the absorption tower and supplied to the regeneration tower is further added. Can include,

In addition, the carbon dioxide separation apparatus may include a concentration meter for measuring the CO ₂ concentration of the absorbent of the absorbent treatment tower.

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

The present invention is to remove the carbon dioxide by using an absorbent that can effectively remove the carbon dioxide when separating the carbon dioxide from the mixed gas, compared to the conventional absorbent, while increasing the surface tension of the absorbent to minimize the film wet phenomenon when applied to the membrane contactor. It can provide a carbon dioxide separation method that can be effective.

The present invention is more effective than the conventional absorbent to remove the carbon dioxide from the mixed gas when applied to the carbon dioxide separation device, while increasing the surface tension of the absorbent by using an absorbent that can minimize the membrane wetting phenomenon when applied to the membrane contactor It is possible to provide a carbon dioxide separation apparatus that can efficiently remove the.

The present invention is to remove the particulate matter in the absorbent by increasing the solubility of the precipitate of the amine or salt present in the absorbent to remove plugging or fouling of the membrane contactor, such as the absorption tower, and fouling (fouling) and separation A device can be provided.

1 is a schematic view showing a carbon dioxide separation apparatus of the present invention.
Figure 2 is a photograph of the membrane contactor used as the absorption tower 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, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention.

However, the following descriptions are not intended to limit the present invention to specific embodiments, and detailed descriptions of well-known technologies related to the present invention will be omitted when it is determined that the present invention may obscure the gist of the present invention. .

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In this application, the terms "comprise" or "having" are intended to indicate that there is a feature, number, step, operation, component, or combination thereof described in the specification, and one or more other features or It should be understood that it does not exclude in advance the possibility of the presence or addition of numbers, steps, operations, components, or combinations thereof.

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

Step (a): Preparation of Final Absorbent

Contact is made of carbon dioxide (CO ₂ ) to the absorbent to prepare a final absorbent absorbed by CO ₂

In step (a), carbon dioxide (CO ₂ ) or a mixture of CO ₂ and an inert gas is contacted with an absorbent to absorb CO ₂ to prepare a pretreated absorbent or to separate a portion of CO ₂ from the pretreated absorbent to obtain a final absorbent. It can manufacture.

In addition, in step (a), carbon dioxide (CO ₂ ) or a mixture of CO ₂ and an inert gas may be contacted with an absorbent to prepare a final absorbent in which CO ₂ is dissolved to remove precipitates or solid particles.

In addition, the absorbent is one or more selected from amino acids and amino acid salts (A); And at least one selected from primary amines, secondary amines and tertiary amines; and at least one selected from potassium carbonate, sodium carbonate, sodium bicarbonate, potassium hydroxide and sodium hydroxide: at least one selected from (B); And water (C) :.

In addition, the absorbent is one or more selected from amino acids and amino acid salts; At least one amine selected from primary amines, secondary amines and tertiary amines; And water :.

In addition, the absorbent is one or more selected from amino acids and amino acid salts; Potassium carbonate, sodium carbonate, sodium bicarbonate, potassium hydroxide and sodium hydroxide; And water :.

In addition, the amino acid salt may be a salt of an amino acid and at least one selected from potassium hydroxide, sodium hydroxide and lithium hydroxide.

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

At least one selected from amino acids and amino acid salts in the aqueous solution (A); And at least one selected from primary amines, secondary amines and tertiary amines; and at least one selected from potassium carbonate, sodium carbonate, sodium bicarbonate, potassium hydroxide and sodium hydroxide: at least one selected from (B); The weight percent concentration (((A + B) / (A + B + C)) x100) of A + B) is 5 to 70 wt%, preferably 20 to 50 wt%, more preferably 30 to 45 wt May be%.

In addition, the surface tension of the absorbent may have a value greater than 70 mN / m.

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

In addition, the amine may be at least one selected from a monoalkanolamine, a polyamine including an amine group having one or two hydrogen atoms, and a cyclic amine.

In addition, the amine is piperazine (piperazine, PZ), 2-amino-2-hydroxymethyl-1,3-propanediol (2-amino-2-hydroxymethyl-1,3-propanediol, AHPD), 2-amino 2-methyl-1,3-propanediol (2-amino-2-methyl-1,3-propanediol, AMPD), 2-aminomethyl-2-hydroxymethyl-1,3-propanol (2-aminomethyl- 2-hydroxymethyl-1,3-propanediol), 2-amino-1,1,1-ethanetriol, hydrazine, ethylenediamine, diethylenetriamine , Triethylenetetraamine, tetraethylenepentaamine, monoethanolamine, diethanolamine, triethanolamine and N-methyldiethanolamine.

Step (b): Preparation of Recycle Absorber

A recycled absorbent may be prepared by separating some or all of the CO ₂ from the final absorbent.

Step (c): Preparation of Saturated Absorbent

Contacting said recirculating absorbent with a gas mixture containing the CO ₂ can be manufactured according to the CO ₂ absorber saturated the reuptake.

Step (d) ₂ To separate and regenerate the saturated absorbent

CO ₂ may be separated from the saturated absorbent and the saturated absorbent may be regenerated.

Next, the carbon dioxide separation apparatus 10 of the present invention will be described with reference to FIG. 1.

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

In the absorbent treatment tower 100, a final absorbent Fc in which CO ₂ is absorbed may be prepared by contacting carbon dioxide (CO ₂ ) or a mixture (Fa) of CO ₂ and an inert gas with the absorbent Fb.

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 may be supplied from the absorbent treatment tower 100, and a part or all of the CO ₂ may be separated from the final absorbent Fc to prepare a recycle absorbent F4. have.

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

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, thermal power plant, landfill gas, and the like.

Carbon dioxide separator 10 of the present invention may further include a heat exchanger (500).

In the heat exchanger 500, the temperature of the recycle absorbent F4 discharged from the regeneration tower 200 and supplied to the absorption tower 300 may be lowered. Alternatively, the heat exchanger 500 may increase the temperature of the saturated final absorbent F2 discharged from the absorption tower 300 and supplied to the regeneration tower 200.

In addition, the carbon dioxide separation apparatus 10 may include a concentration meter 210 for measuring the CO ₂ concentration of the absorbent of the absorbent treatment tower 100 on the absorbent treatment tower 100.

In addition, the carbon dioxide separation unit 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.

In addition, the carbon dioxide separation apparatus 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 Figure 1, 5L of absorbent (Fb) at room temperature was prepared in a concentration of 2.5 M piperazine (PZ) and 1.0 M potassium serinate (K-Ser) was injected into the absorbent treatment tower 100 of 40 ℃. When the amino acid is added, since the amino acid is cationized in the aqueous solution, equimolar KOH is slowly added to neutralize the cationized amino acid and then added.

The mixture (Fa) having a volume ratio of CO ₂ : N ₂ = 15%: 85% was prepared using a mass flow controller, and the flow rate of CO ₂ was injected by bubbling the absorbent at 10 L / min. The concentration of CO ₂ discharged from the rear end of the absorbent treatment tower 100 was measured using a 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 the final absorbent

In order to prepare the remaining pretreatment absorbent manufactured in the treatment tower 100 as the final absorbent, after raising the temperature of the treatment tower to 80 ° C and reaching a steady state, nitrogen at the same flow rate as the pretreatment is injected into the pretreatment absorbent and the CO ₂ was removed. When the concentration of CO ₂ measured in the real-time gas analyzer 210 reached 1%, the stripping reaction was terminated to prepare a final absorbent (Fc) prepared for the actual process.

CO ₂  Reabsorption

The final absorbent (Fc) finally obtained after the removal of CO ₂ is introduced into the regeneration tower, passed through the heat exchanger 500, the temperature is about 60 ℃ and circulated to the 40 ℃ CO ₂ absorption tower 300 to reabsorb CO ₂ Was run. This recycling absorbent (F4) can be said to be the absorbent (F4) in the actual CO ₂ separation step.

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

CO ₂ Separation

Referring to FIG. 1, the CO ₂ saturated absorbent (F ₂ ) was passed through a heat exchanger (500), and then heated to 120 ° C. in a regeneration tower (200) to separate CO ₂ due to thermal energy and regenerate the absorbent. Recycled absorbent (F4) is separated and regenerated CO ₂ was passed through the heat exchanger 500 and then introduced to the top of the absorption tower.

Example  2

Absorbent (Fb) at room temperature 5L of 2.5 M piperazine (PZ) and 1.0 M potassium serinate (K-Ser) concentration of the absorbent (Fb) at room temperature instead of injecting into the absorbent treatment tower 100 at 40 ℃ 5L of monoethanolamine (MEA) was prepared in the same manner as in Example 1 except that the concentration of 5.0 M was injected into the absorbent treatment tower 100 at 40 ° C.

Comparative example  One

Without the absorbent pretreatment as in Example 1, 5L of a 2.5 M piperazine (PZ) and a 1.0 M potassium serinate (K-Ser) aqueous solution (Fb ') was prepared at room temperature. Referring to Figure 3, the absorbent (Fb ') was injected into the lumen side of the hollow fiber membrane membrane contactor of the absorption tower at a flow rate of 62 ml / min in the upper portion of the CO ₂ absorption tower 300' at 60 ℃. However, when the aqueous solution of 2.5 M piperazine (PZ) and 1.0 M potassium serinate (K-Ser) was prepared at room temperature, precipitates were not dissolved, and after visual confirmation that the precipitates did not exist by stirring with a stirrer at 80 ° C. for 2 hours or more. Into the absorption tower (300 '). CO ₂ : N ₂ = 15%: 85% by volume of the mixed gas (F1 ') was injected into the shell side of the absorption tower 300' at 36 ml / min based on the CO ₂ flow rate was carried out CO ₂ absorption.

The CO ₂ saturated absorbent (F2 ') absorbing CO ₂ is fed to the regeneration tower 200' through a heat exchanger 500 'and heated to 120 ° C. in the regeneration tower 200' to separate CO ₂ due to thermal energy. Regeneration of the absorbent took place. CO ₂ is separated from the regenerated recycle absorbent (F4 ') is re-heat exchanger (500 "were then passed through a) introducing to the top of the absorber 300'.

Comparative example  2

Instead of using 2.5 M piperazine (PZ) and 1.0 M potassium serinate (K-Ser) water absorbent (Fb '), except that 5.0 M concentration of monoethanolamine (MEA) water absorbent (Fb') was used. Was carried out in the same manner as in Comparative Example 1.

[Test Example]

Test Example  1: CO ₂  Removal rate

The absorbent was prepared by calculating the amount of absorbent required for the membrane contactor experiment for CO ₂ resorption. Specifications of the membrane contactor for testing the performance of the absorbent are shown in Table 1, and a photograph of the membrane contactor is shown in FIG. Five minutes after the recycle absorbent is added to the absorption tower, the CO ₂ removal rate is calculated by the following Equation 1 and shown in Table 2.

[Calculation 1]

CO ₂ removal rate (%) = ((C ₁ -C ₂ ) / C ₁ ) x100

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

Kinds value Fiber outer diameter (μm) 840 Fiber inside diameter (μm) 600 Fiber void percentage (%) 67 Fiber length (mm) 270 Number of fibers 100 Average pore size (μm) 0.15 Module Packing Density (%) 45

Referring to Table 2, CO ₂ was partially absorbed through the treatment tower under the same conditions, and the pretreated absorbent showed about 5% higher CO ₂ removal rate under the same conditions than the other absorbent.

Kinds Absorbent Pretreatment or not 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 Absorbents

4, the turbidity of the absorbent prepared at room temperature (left) and the absorbent (right) bubbling CO ₂ at room temperature (right) (absorbent: 2.5 M piperazine (PZ) + 1.0 M potassium serinate (K-Ser)) Observed visually. In the preparation of 2.5 M piperazine (PZ) + 1.0 M potassium serinate (K-Ser) at room temperature, a large amount of sediment was generated, but the CO ₂ bubbling pretreatment in the treatment tower disappeared and became clear in the solution. For reference, when the absorbent is heated to 40 ° C. and only stirred, the precipitate is not removed. However, when the solution is heated to 80 ° C., the precipitate is generated again when the solution approaches room temperature.

Test Example  3: Surface tension

The surface tension of the stripping absorbent (lean CO ₂₎ and then absorb the CO ₂ through the pre-treatment in the absorber (fresh) to the processing tower that has not absorbed the CO ₂ using the Kruss BP2 model's was measured at 25 ℃.

Referring to Table 3, in the case of 2.5 M PZ + 1.0 M K-Ser solution, when CO ₂ is bubbling and a certain amount of CO ₂ is present in the absorbent, the surface tension increases by 1.9 mN / m at 25 ° C, which is 30 wt. Compared to% MEA, the surface wetting phenomenon was reduced due to the higher surface tension.

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

As mentioned above, although preferred embodiments of the present invention have been described, those of ordinary skill in the art may add, change, delete, or eliminate the elements within the scope of the present invention described in the claims. The present invention may be variously modified and changed by addition, etc., which will also be included within the scope of the present invention. For example, each component described as a single type may be implemented in a distributed manner, and similarly, components described as distributed may be implemented in a combined form. The scope of the present invention is shown by the following claims rather than the above description, and all changes or modifications derived from the meaning and scope of the claims and their equivalents should be construed as being included in the scope of the present invention. do.

Claims (12)

Serine salt (A);
Piperazine (B); And
It is an absorbent containing water (C);
The serine salt is a salt of potassium hydroxide and serine,
The ratio (M1: M2) of the molar concentration (M1) of the piperazine and the molar concentration (M2) of the serine salt in the absorbent is 1: 0.4,
The absorbent is for use in separating carbon dioxide from the mixed gas,
The concentration (((A + B) / (A + B + C)) × 100) in the absorbent is 30 to 45% by weight,
The surface tension of the absorbent has a value greater than 70 mN / m,
The absorbent is that absorbent CO ₂ is dissolved by contacting carbon dioxide (CO ₂ ) or a mixture of CO ₂ and an inert gas, the absorbent is removed. delete delete delete delete delete delete delete delete delete delete delete

Images