KR20180124655A - Absorbent For Carbon Dioxide and Method for Manufacturing The Same - Google Patents

Abstract

The present invention relates to an absorbent for capturing carbon dioxide for removing carbon dioxide in an IGCC process and a manufacturing method thereof, and more specifically, to a carbon dioxide absorbent in which hydrocarbon oil is in the form of a droplet, and to a manufacturing method thereof. According to the carbon dioxide absorbent of the present invention, since droplets other than solid particles are used, a coagulation phenomenon does not occur to require a small amount of energy consumption for redispersion and tube corrosion does not occur. In addition, there is an effect of providing a high-efficiency carbon dioxide absorbent, which enables not only the surface of the absorbent but also the internal absorption phenomenon.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a carbon dioxide absorbent,

The present invention relates to an absorbent for capturing carbon dioxide for removing carbon dioxide in an IGCC process and a method for producing the same. More particularly, the present invention relates to a carbon dioxide absorbent having a hydrocarbon oil in the form of a droplet, and a method for producing the same.

Gasification Combined Cycle (IGCC) is a combined power generation system that produces syngas by fossil fuel gasification at high temperature and high pressure and produces electricity by using it as fuel. It has energy efficiency higher than thermal power generation using existing boiler, It is attracting attention as a clean power generation technology. However, since the greenhouse gases emitted by the use of fossil fuels cause global warming, the importance of carbon dioxide capture and storage (CCS), which isolates carbon dioxide from the atmosphere, which is the main cause of global warming, is emphasized. It is coming. In particular, IGCC can reduce the cost of power generation because it can remove carbon dioxide at a lower cost than conventional thermal power generation in connection with CO2 capture facility.

In the IGCC process, the capture process for removing carbon dioxide can be divided into chemical absorption process, physical absorption process, adsorption process, membrane separation process, and deep seawater process, which are processes using reaction, dissolution, adsorption and distillation respectively. The chemical absorption method (Korean Patent No. 10-1311783, entitled "Amine-based absorbent and its production method") requires a large energy for regenerating the absorbent and has a disadvantage that the equipment is corroded by the absorbent. Disadvantages, membrane separation method is disadvantageous in that the separation membrane is expensive, and it is difficult to increase the capacity, and the deep cooling method has a disadvantage of consuming a large amount of energy.

In a large-scale process such as IGCC, the physical absorption method is most suitable because the device is relatively simple and dry, and the influence on the surrounding environment is small. Genosorb, Selexol, Rectisol, and Purisol processes are known as processes using the physical absorption method.

The lectisol process uses methanol as the absorber and requires large refrigeration energy to maintain a low temperature (-40 ° C) to achieve the desired absorption rate. Energy and cost savings can be expected if the process can be operated at room temperature by increasing the absorption capacity of the absorbent. To this end, research has been conducted to increase the absorption rate by using nanofluids. Solid particles such as Al ₂ O ₃ , SiO ₂ , and Fe ₃ O ₄ used in the nanofluid coagulate, which is a phenomenon of aggregation, and the precipitated particles cause corrosion in the tube. In addition, the solid particles are not effective because absorption occurs only on the surface of the particles. Therefore, it is required to develop a high-efficiency absorbent which does not cause aggregation phenomenon with low energy consumption.

Korean Patent No. 10-1311783

SUMMARY OF THE INVENTION It is an object of the present invention to provide a high-efficiency carbon dioxide absorbent which is low in energy consumption and does not cause aggregation, and a method for producing the same.

The carbon dioxide absorbent for achieving the above object includes a solvent, a hydrocarbon oil dispersed in the solvent, and a surfactant mixture, and the hydrocarbon oil is in a droplet form.

The solvent may be selected from the group consisting of methanol, N-methyl-2-pyrrolidone, dimethyl ether polyethylene glycol (DMPEG), dimethyl carbonate (DMC) , Diethyl carbonate (DEC), triacetin (TAT, triacetin), and the like.

The hydrocarbon oil may be a hydrocarbon oil in which all the bonds in the molecule may be a single bond and may be any of n-pentane, n-hexane, n-heptane, n-octane, n-dodecane, n-tridecane, n-tetradecane, n-pentadecane, n-hexadecane, and n-heptadecane.

The mixture of the surfactants may be any one or more selected from the group consisting of anionic surfactants, cationic surfactants, nonionic surfactants and amphoteric surfactants. In other words, the mixture may be prepared so that the difference from the HLB of the hydrocarbon oil is 1 or less Equation (1) can be satisfied.

HLB _x is the HLB of the hydrocarbon oil,

The HLB _y is the HLB of the surfactant mixture.

The volume of the surfactant mixture may be at least 0.125 times and less than 0.25 times the volume of the hydrocarbon oil.

The present invention also provides a process for producing a carbon dioxide absorbent characterized in that the hydrocarbon oil is in the form of a droplet.

The method includes the steps of forming a first solution by adding hydrocarbon oil to a first solvent, forming a second solution by adding a surfactant mixture to the second solvent, and mixing the first solution and the second solution do. Mixing the first solution and the second solution, and further dividing the droplet.

The first solvent and the second solvent may be selected from the group consisting of methanol, N-methyl-2-pyrrolidone, dimethyl ether polyethylene glycol (DMPEG) And may be any one selected from the group consisting of carbonate (DMC), diethyl carbonate (DEC), triacetin (TAT, triacetin), and the like.

The hydrocarbon oil may be any bond in the molecule which may be a single bond and is selected from the group consisting of n-pentane, n-hexane, n-heptane, n-octane, n-dodecane, n-tridecane, n-tetradecane, n-pentadecane, n-hexadecane, and n-heptadecane.

The mixture of the surfactants may be any one or more selected from the group consisting of anionic surfactants, cationic surfactants, nonionic surfactants and amphoteric surfactants. In other words, the mixture may be prepared so that the difference from the HLB of the hydrocarbon oil is 1 or less Equation (1) can be satisfied.

[Equation 1]

HLB _x is the HLB of the hydrocarbon oil,

The HLB _y is the HLB of the surfactant mixture.

The volume of the surfactant mixture may be at least 0.125 times and less than 0.25 times the volume of the hydrocarbon oil.

According to the carbon dioxide absorbent of the present invention, since droplets that are not solid particles are used, coagulation phenomenon does not occur, energy consumption required for redispersing the absorbent is small, and tube corrosion does not occur. It is also effective to provide a high-efficiency carbon dioxide absorbent capable of absorbing not only the surface of the absorbent but also the inside of the absorbent.

1 is a schematic view schematically showing a method for producing a carbon dioxide absorbent according to claim 8 of the present invention.
2 is a schematic view schematically showing a method of producing a carbon dioxide absorbent according to Example 1 and Comparative Examples 1 to 5 of the present invention.
FIG. 3 is a schematic view showing an experimental procedure for measuring scattered light of a carbon dioxide absorbent according to Example 1 and Comparative Examples 1 to 5. FIG.
4 is an image showing the results of an experiment for measuring scattered light of a carbon dioxide absorbent according to Example 1 and Comparative Examples 1 to 5 of the present invention.
5 is a graph showing the turbidity measurement results of the carbon dioxide absorbent according to Example 1 and Comparative Examples 1 to 5 of the present invention.

Hereinafter, the present invention will be described in detail with reference to embodiments and drawings according to the present invention.

The carbon dioxide absorbent for achieving the above object includes a solvent, a hydrocarbon oil dispersed in the solvent, and a surfactant mixture, and the hydrocarbon oil is in a droplet form.

The solvent may be selected from the group consisting of methanol, N-methyl-2-pyrrolidone, dimethyl ether polyethylene glycol (DMPEG), dimethyl carbonate (DMC) , Diethyl carbonate (DEC), triacetin (TAT, triacetin), and the like. All of these solvents are suitable for absorbents since their purity of carbon dioxide separation is 90% or more.

The hydrocarbon oil may be a single bond in which all the bonds in the molecule are bonded. Of these, n-pentane, n-hexane, n-heptane, n-octane, n-nonane, n-decane, which have a melting point of 0 ° C or lower and a boiling point of 25 ° C or higher, , n-decane, n-dodecane, n-tridecane, n-tetradecane, n-pentadecane, n-hexadecane and n-heptadecane have.

The surfactant mixture is added to surround the hydrocarbon oil droplet to increase the dispersibility. The surfactant may be any one selected from the group consisting of an anionic surfactant, a cationic surfactant, a nonionic surfactant, and a positive surfactant. Such an anion surfactant refers to a surfactant having an anionic long chain atomic group (hydrophobic portion), and includes a soap, a phosphate ester, a sulfate, a sulfonate, and the like. The cationic surfactant refers to a surfactant having a long-chain cation, and includes quaternary ammonium salts, amine salts, and pyridine salts. Nonionic surfactants are surfactants that do not have a charge group, and include polyethylene glycol, polyhydric alcohols, fatty acid ethylene oxide, and the like. Amphoteric surfactants are surfactants that have both positive and negative ions in the molecule. They are controlled by pH and have amino acid type and beta type.

That is, the mixture of the surfactant mixture may satisfy the following equation (1) so that the difference from the HLB of the hydrocarbon oil is 1 or less.

[Equation 1]

HLB _x is the HLB of the hydrocarbon oil,

The HLB _y is the HLB of the surfactant mixture.

Hydrophilic Lipophilic Balance (HLB) is a numerical representation of the hydrophilicity and lipophilicity of a surfactant. HLB begins with 1 as the most lipophilic one, and the widely used surfactant has HLB usually between 1 and 20. Specifically, the HLB value of the surfactant mixture can be obtained by the following equation (2).

Wherein W _A And W _B are the weight fractions of the surfactant to be mixed, respectively.

Sorbitan monooleate, Sorbitan monooleate, Sorbitan monostearate, Sorbitan monooleate, Sorbitan monooleate, Sorbitan monooleate, Sorbitan trioleate, Sorbitan monooleate, Sorbitan monostearate, Sorbitan monooleate, polyoxyethylene (5) sorbitan monooleate, triethanolamine oleate, polyoxyethylene (20) sorbitan monostearate (polyoxyethylene sorbitan monostearate) ), Polyoxyethylene (20) sorbitan monooleate, Polyoxyethylene (20) sorbitan monolaurate, Sodium oleate, Potassium oleate (Potassium oleate), Polyoxyethylene sorbitan monolaurate Oleate), but are not limited thereto.

The volume of the surfactant mixture may be at least 0.125 times and less than 0.25 times the volume of the hydrocarbon oil.

The method for producing a carbon dioxide absorbent according to the present invention includes the steps of forming a first solution by adding hydrocarbon oil to a first solvent, Adding a surfactant mixture to the second solvent to form a second solution, and mixing the first and second solutions. Mixing the first solution and the second solution, and further dividing the droplet. As an example of the step of dividing the droplet further, ultrasonic treatment may be used. The droplet size may be adjusted by changing the ultrasonic treatment time or frequency.

The first and second solvents may be selected from the group consisting of methanol, N-methyl-2-pyrrolidone, dimethyl ether polyethylene glycol (DMPEG), dimethyl carbonate (DMC, dimethyl carbonate), diethyl carbonate (DEC, diethyl carbonate), triacetin (TAT, triacetin). All of these solvents are suitable for absorbents since their purity of carbon dioxide separation is 90% or more.

The hydrocarbon oil may be a single bond in which all the bonds in the molecule are bonded. Of these, n-pentane, n-hexane, n-heptane, n-octane, n-nonane, n-decane, which have a melting point of 0 ° C or lower and a boiling point of 25 ° C or higher, , n-decane, n-dodecane, n-tridecane, n-tetradecane, n-pentadecane, n-hexadecane and n-heptadecane have.

The surfactant mixture is added to the droplets of the hydrocarbon oil to increase the dispersibility. The surfactant may be any one selected from the group consisting of an anionic surfactant, a cationic surfactant, a nonionic surfactant, and a positive surfactant. Such an anion surfactant refers to a surfactant having an anionic long chain atomic group (hydrophobic portion), and includes a soap, a phosphate ester, a sulfate, a sulfonate, and the like. The cationic surfactant refers to a surfactant having a long-chain cation, and includes quaternary ammonium salts, amine salts, and pyridine salts. Nonionic surfactants are surfactants that do not have a charge group, and include polyethylene glycol, polyhydric alcohols, fatty acid ethylene oxide, and the like. Amphoteric surfactants are surfactants that have both positive and negative ions in the molecule. They are controlled by pH and have amino acid type and beta type.

That is, the mixture of the surfactant mixture may satisfy the following equation (1) so that the difference from the HLB of the hydrocarbon oil is 1 or less.

[Equation 1]

HLB _x is the HLB of the hydrocarbon oil,

The HLB _y is the HLB of the surfactant mixture.

Hydrophilic Lipophilic Balance (HLB) is a numerical representation of the hydrophilicity and lipophilicity of a surfactant. HLB begins with 1 as the most lipophilic one, and the widely used surfactant has HLB usually between 1 and 20. Specifically, the HLB value of the surfactant mixture can be obtained by the following equation (2).

&Quot; (2) "

W _A and W _B are the weight fraction of the surfactant to be mixed, respectively.

Sorbitan monooleate, Sorbitan monooleate, Sorbitan monostearate, Sorbitan monooleate, Sorbitan monooleate, Sorbitan monooleate, Sorbitan trioleate, Sorbitan monooleate, Sorbitan monostearate, Sorbitan monooleate, polyoxyethylene (5) sorbitan monooleate, triethanolamine oleate, polyoxyethylene (20) sorbitan monostearate (polyoxyethylene sorbitan monostearate) ), Polyoxyethylene (20) sorbitan monooleate, Polyoxyethylene (20) sorbitan monolaurate, Sodium oleate, Potassium oleate (Potassium oleate), Polyoxyethylene sorbitan monolaurate Oleate), but are not limited thereto.

The volume of the surfactant mixture may be at least 0.125 times and less than 0.25 times the volume of the hydrocarbon oil.

Hereinafter, the present invention will be described in detail with reference to examples. However, the following examples are illustrative of the present invention, and the contents of the present invention are not limited to the following examples.

{Example}

The operation for all carbon dioxide sorbents was carried out at a temperature below 20 ° C and a pressure of 4 bar of carbon dioxide. N-Dodecane was used as the hydrocarbon oil. Sorbitan monostearate (Span ^® 60) with an HLB of 4.7, Polyoxyethylene (20) sorbitan monostearate with an HLB of 15.6 to match the HLB of n-dodecane of 10.5, Tween ^® 60) were selected. Span ( ^R) 60 and Tween ( ^R) 60 were mixed at a weight ratio of 4: 6 using the calculation method of Equation (2). Methanol was used as a solvent.

One. Example  One

Dissolve the first solution containing n-dodecane in pure methanol for 30 minutes to form a droplet by ultrasonication and stirring. Add a second solution of Span ^® 60 and Tween ^® 60 at a weight ratio of 4: 6 to pure methanol for 30 minutes Mixing the first solution and the second solution, and ultrasonically treating and stirring the mixture for 2 hours to form a n-dodecane droplet coated with a surfactant, thereby preparing a carbon dioxide absorbent. At this time, the volume ratio of n-dodecane and mixed surfactant (Span ^® 60 and Tween ^® 60) was set to 1: 0.25.

2. Comparative Example  One

The first solution containing n-dodecane in pure methanol without surfactant was ultrasonically treated and stirred for 30 minutes to form a droplet, thereby preparing a carbon dioxide absorbent.

3. Comparative Example  2

A carbon dioxide absorbent was prepared in the same manner as in Example 1, except that the volume ratio of n-dodecane and mixed surfactant was 1: 0.125.

4. Comparative Example  3

A carbon dioxide absorbent was prepared in the same manner as in Example 1 except that the volume ratio of n-dodecane and mixed surfactant was 1: 0.5.

5. Comparative Example  4

A carbon dioxide absorbent was prepared in the same manner as in Example 1, except that the volume ratio of n-dodecane and mixed surfactant was 1: 1.

6. Comparative Example  5

A carbon dioxide absorbent was prepared in the same manner as in Example 1, except that the volume ratio of n-dodecane and mixed surfactant was 1: 2.

{evaluation}

The dispersion stability is evaluated by the scattered light measurement method and the turbidity test method.

The scattered light measurement method is based on the tinned effect in which the laser projected onto the reagent is visualized by the scattering and reflection of the reagent. The degree of visualization varies depending on the degree of dispersion. When the light is blurred, it means that the reagent has settled, and when the phenomenon of spreading of the light is observed, it means that the reagent forms agglutination. Therefore, when the light is clear and close to a straight line, it is evaluated that dispersion stability is good.

The apparatus for measuring scattered light is shown in Fig. Place the prepared carbon dioxide absorbent into a 30 ml vial bottle and place it 5 cm away from the laser. At this time, 5 cm was determined as the position with the highest sharpness when the laser was projected onto the vial bottle. In order to evaluate the dispersion stability according to various positions, the laser is projected at four places: Bottom, Lower middle, Upper middle and Up. Immediately after the manufacture, images are taken according to time, and the sharpness of light is compared and evaluated.

The turbidity measurement is a numerical measurement of the degree to which light passing through the reagent is scattered. The unit is NTU (Nephelometric Turbidity Units). At this time, the NTU value is measured from immediately after manufacture to the time, and the extent to which the NTU changes over time is evaluated. If the NTU value measured after a certain period of time decreases faster than the initial NTU value, it is evaluated that the dispersion stability is low. In case of NTU value, a total of 5 measurements were made and the mean value was selected as data and error was added.

Comparing the sharpness of light with NTU shows a similar tendency.

Evaluation of dispersion stability

The scattered light measurement and turbidity test data of Experimental Example 1 and Comparative Examples 1 to 5 are shown in Figs. 4 and 5. In FIG. 5, it can be seen that the larger the value of NTU, the clearer the laser path in FIG. 4, and the larger the amount of surfactant added, the greater the maximum value of NTU.

In the case of Comparative Example 1 and Comparative Example 2, the NTU steadily decreased and the dispersion stability collapsed at an early time.

In the case of Comparative Example 3, NTU decreases rapidly after 90 minutes and is unstable.

In Comparative Example 4, in the scattered light measurement data of FIG. 4, it can be seen that the dispersion stability was collapsed due to the difference in color of the laser light at the center portion and the edge portion in the laser path at 360 minutes.

In the case of Comparative Example 5, the dispersion stability was low due to a large decrease in NTU over time as compared with other cases.

As a result, it was estimated that phase separation could not be carried out and dispersion stability was not achieved well. Therefore, it was determined that the dispersion stability of the carbon dioxide absorbent prepared in Example 1 was the best.

Although the present invention has been described in connection with the above-mentioned preferred embodiments, it is possible to make various modifications and variations without departing from the spirit and scope of the invention. It is therefore intended that the appended claims cover all such modifications and variations as fall within the true spirit of the invention.

Claims (15)

menstruum;
A hydrocarbon oil dispersed in the solvent; And
A surfactant mixture,
Wherein the hydrocarbon oil is in the form of droplets. The method according to claim 1,
Wherein the solvent is at least one selected from the group consisting of methanol, N-methyl-2-pyrrolidone, dimethylether polyethylene glycol, dimethyl carbonate, diethyl carbonate and triacetin. The method according to claim 1,
Wherein the hydrocarbon oil is a single bond in which all the bonds in the molecule are single bonds. The method of claim 3,
The hydrocarbon oil may be n-pentane, n-hexane, n-heptane, n-octane, n-nonene, wherein the carbon dioxide absorbent is any one selected from the group consisting of n-heptadecane, n-tetradecane, n-pentadecane, n-hexadecane and n-heptadecane. The method according to claim 1,
Wherein the surfactant mixture is at least one selected from the group consisting of anionic surfactants, cationic surfactants, nonionic surfactants, and amphoteric surfactants. The method according to claim 1,
Wherein the surfactant mixture satisfies the following formula (1): < EMI ID = 1.0 >
[Equation 1]

HLB _x is the HLB of the hydrocarbon oil,
The HLB _y is the HLB of the surfactant mixture. The method according to claim 1,
Wherein the volume of said surfactant mixture is at least 0.125 times and less than 0.25 times the volume of said hydrocarbon oil. Adding a hydrocarbon oil to the first solvent to form a first solution;
Adding a surfactant mixture to a second solvent to form a second solution; And
Mixing the first solution and the second solution,
Wherein the hydrocarbon oil is in the form of a droplet. 9. The method of claim 8,
Further comprising mixing the first solution and the second solution and then further splitting the droplet. 9. The method of claim 8,
Wherein the first solvent and the second solvent are each selected from the group consisting of methanol, N-methyl-2-pyrrolidone, dimethylether polyethylene glycol, dimethyl carbonate, diethyl carbonate, triacetin, Absorbent. 9. The method of claim 8,
Wherein the hydrocarbon oil is a single bond in which all the bonds in the molecule are single bonds. 12. The method of claim 11,
The hydrocarbon oil may be n-pentane, n-hexane, n-heptane, n-octane, n-nonene, n-pentadecane, n-hexadecane, n-tetradecane, n-pentadecane, and n-hexadecane. 9. The method of claim 8,
Wherein the surfactant mixture is at least one selected from the group consisting of an anionic surfactant, a cationic surfactant, a nonionic surfactant, and an amphoteric surfactant. 9. The method of claim 8,
Wherein the surfactant mixture satisfies the following formula (1): < EMI ID = 1.0 >
[Equation 1]

HLB _x is the HLB of the hydrocarbon oil,
The HLB _y is the HLB of the surfactant mixture. 9. The method of claim 8,
Wherein the volume of said surfactant mixture is at least 0.125 times and less than 0.25 times the volume of said hydrocarbon oil.

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