KR101695030B1 - Carbon dioxide absorbent absorbent and method for preparing the same - Google Patents

Abstract

The present invention relates to a carbon dioxide absorbent and a method for producing the carbon dioxide absorbent. In the present invention, through the coating layer containing precipitated carbonate, the repulsive force between the particles is increased to prevent agglomeration between the powders, thereby improving the flowability of the absorbent. It is possible to provide a carbon dioxide absorbent and a method of manufacturing the carbon dioxide absorbent which can not only be advantageous in long term storage and transportation of absorbent through improved flow properties but also can reduce physical abrasion and improve abrasion resistance.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a carbon dioxide absorbent,

The present invention relates to a carbon dioxide absorbent and a method for producing the same.

The carbon dioxide absorbent is a dry regenerated carbon dioxide absorbent (hereinafter referred to as " absorber ") necessary for recovering carbon dioxide generated by the conversion of fossil fuels in the industry such as thermal power plants and discharged to the atmosphere by using dry regeneration absorption technology. Can be used.

More specifically, the carbon dioxide sorbent can be used to recover carbon dioxide in a fluidized-bed or fast-transport absorption reactor and in a fluidized bed or fast fluidized bed regenerative reactor.

Carbon dioxide is one of the greenhouse gases and is known to have the greatest impact on global warming due to the release of carbon dioxide to the atmosphere as the use of fossil fuels increases. Failure to control these emissions of carbon dioxide could lead to global environmental disasters caused by global warming. Carbon dioxide can be removed from a syngas stream produced by the combustion of fossil fuels, ie, syngas produced by flue gas, coal gasification, or natural gas (referred to as fuel gas). That is, carbon dioxide can be removed from the exhaust gas, syngas or fuel gas. Wet chemical cleaning, adsorption, membrane separation, and cold cooling separation are methods for removing carbon dioxide from the flue gas, but they are difficult to use for recovering carbon dioxide from a large amount of flue gas because of high cost.

Dry chemical cleaning is a method of removing carbon dioxide from flue-gas. This is a technique that uses solids instead of liquid solvents used in wet chemical cleaning. The active ingredient and carbon dioxide in the solid absorbent react chemically in the absorption reactor to produce carbonates or bicarbonates, which removes carbon dioxide from the gas stream and absorbs the carbon dioxide, which can be used repeatedly by regenerating the heat in the regeneration reactor It is called dry regenerable sorbent technology.

The characteristics of dry regeneration absorption technology are as follows: First, materials are low cost, can be reused and reused, can be continuously developed in comparison with other technologies in terms of design flexibility, environment friendly, low energy absorbing process application, high efficiency carbon dioxide absorbing ability and reaction speed to be.

In the fluidized bed or high-speed fluidized bed process for recovering carbon dioxide, it is important that the shape and mechanical strength of the absorbent as well as the reactivity (absorbency and reaction rate) of the absorbent are used to regenerate the absorbent several times. Particularly, while the solid particles (absorbent) circulate at high speed between the two reactors, the particles are abraded with finer particles due to collision, friction, breakage or crack, etc., and the absorbing ability is lowered. There is a problem in that the caking characteristics of the powder deteriorates due to the moisture around the powder when stored for a long period of time.

In order to solve such problems, conventionally, the strength of the absorbent has been increased to reduce the physical abrasion. However, when the strength of the absorbent is increased, the absorbency of the absorbent is difficult to develop because of its relatively low reactivity.

It is an object of the present invention to increase the utilization of the active ingredient through an even distribution of active ingredients, to provide a wide specific surface area required for the reaction, and to provide a form suitable for high temperature drying, particularly for fluidized bed or fast fluidized bed carbon dioxide absorption processes, (Strength) and heat resistance of the carbon dioxide absorbent having a size and a distribution.

Another object of the present invention is to provide a method for efficiently producing the carbon dioxide absorbent.

Another object of the present invention is to provide a spray drying apparatus capable of producing a carbon dioxide absorbent according to the present invention.

It is also an object of the present invention to provide a method for reducing carbon dioxide using the carbon dioxide absorbent of the present invention.

The present invention provides, as means for solving the above-mentioned problems, a core layer in which an active component capable of reacting with carbon dioxide is supported in a support; And a coating layer surrounding the core layer and containing a precipitated carbonate.

The present invention also relates to a method for producing a carbonaceous material, comprising the steps of: drying a slurry comprising a carbon dioxide absorbent raw material and a solvent to form a powdery core layer; Forming a coating layer containing a precipitated carbonate on the core layer; And drying and firing the core layer and the coating layer.

Further, as another means for solving the above-mentioned problem, there are provided a spray nozzle 1 installed inside the chamber 10 for spraying the raw material supplied from the carbon dioxide absorbent raw material supply part; A high temperature drying blower 3 installed at one side of the chamber 10 to blow hot air into the chamber 10; A powder collecting device (4) installed at a lower portion of the chamber (10) and collecting the powder; And a coating spray nozzle (2) installed in the chamber (10) for spraying a coating agent containing precipitated carbonate.

The present invention also provides a method for reducing carbon dioxide, comprising the step of contacting a carbon dioxide-containing gas with the carbon dioxide absorbent according to the present invention as means for solving the above problems.

In the present invention, it is possible to increase the repulsive force between the particles through the coating layer containing the precipitated carbonate, thereby preventing agglomeration between the powders and thereby improving the flowability of the absorbent, and through such improved flowability, It is possible to provide a carbon dioxide absorbent which can not only be advantageous but also can reduce physical abrasion and improve wear resistance, and a method for producing the carbon dioxide absorbent.

1 is a cross-sectional view of a spray drying apparatus according to an embodiment of the present invention;

The present invention relates to a core layer in which an active component capable of reacting with carbon dioxide is supported in a support; And a coating layer surrounding the core layer and containing a precipitated carbonate.

Hereinafter, the carbon dioxide absorbent of the present invention will be described in detail.

In the present invention, the core layer may be used without limitation as long as the active ingredient is supported on the support, and the active ingredient is a substance capable of selectively recovering and separating carbon dioxide from the gas stream by selectively reacting with the carbon dioxide.

The content of the active ingredient in the present invention is not particularly limited and may be included in an amount of 30 to 50 parts by weight, preferably 40 to 50 parts by weight, based on the carbon dioxide absorbent. If the content of the active ingredient is less than 30 parts by weight based on the total weight of the absorbent, there is a fear that the absorbing ability is lowered. If the content of the active ingredient is more than 50 parts by weight, the content of the support is relatively decreased.

In the present invention, the support can provide the pores structure necessary for diffusing the reactive gas by increasing the reactivity by distributing the active ingredient in the particles of the absorbent, providing the strength of the absorbent after firing, and adsorbing or absorbing the moisture required for the reaction And can be used without limitation as long as it has self-hydrophilicity or can impart hydrophilicity to the absorbent. Examples of the support include ceramics, natural or synthetic zeolite, diatomaceous earth and carbon sieves A support containing at least one member selected from the group consisting of

Examples of the ceramics include alumina, silica, magnesia, zirconia, and titania.

The content of the support in the present invention is not particularly limited and can be included in an amount of, for example, 50 to 70 parts by weight, and preferably 60 to 70 parts by weight, based on the total weight of the absorbent. If the content of the support is less than 50 parts by weight, the strength may be reduced and the wear resistance may be increased. If the content is more than 70 parts by weight, the carbon dioxide absorbing ability may deteriorate.

In the present invention, the precipitated carbonate is contained in the coating layer surrounding the core layer, and the precipitated carbonate serves as a fine coating film on the core layer. By this characteristic, the repulsive force between the absorbent increases, It prevents agglomeration between particles. The precipitated carbonate which can be used in the present invention is a metastable carbonate compound precipitated from water, such as an alkaline earth metal-containing water such as brine, and the precipitated carbonate of the present invention includes precipitated crystals and / or amorphous carbonate compounds.

The precipitated carbonate in the present invention is not particularly limited and may be contained in an amount of 2 to 6 parts by weight based on the total weight of the absorbent. If the content of the precipitated carbonate is less than 2 parts by weight, the effect of improving the flowability is insignificant. If the content of the precipitated carbonate is more than 6 parts by weight, there is a possibility that the absorption capacity is lowered due to excessive surface coating.

The precipitated carbonate is produced by producing a carbonate compound precipitate from water, and then separating the resulting precipitated carbonate compound from the mother liquor to produce a separated carbonate compound precipitation product. The sediment may be prepared by any conventional method, for example by draining water from the sediment and using a conventional method such as filtering the sediment from the mother liquor using mechanical pressing And then dried to prepare a precipitated carbonate.

In the present invention, the core layer may further comprise an inorganic binder.

In the present invention, the inorganic binder is filled in the core layer densely to produce a high-density carbon dioxide absorbent, and enhances the strength of the absorbent by increasing the binding force between the active ingredient and the support. The kind of the inorganic binder usable in the present invention is not particularly limited. Cement such as calcium silicate and calcium aluminate; Clays such as bentonite and kaolin; And ceramics such as alumina sol, silica sol, boehmite and the like, and more preferably at least one selected from the group consisting of calcium silicate, calcium aluminate, bentonite, kaolin, alumina sol, silica sol And pseudo-boehmite, and the like.

The type of the cement-type inorganic binder is not particularly limited, and examples thereof include Portland cement or anhydrous calcium silicate among hydraulic cements.

The type of the clay-like binder is not particularly limited. For example, sodium clay-like binders belonging to smectites and kandites include sodium bentonite or kaolin which is plasticized in an aqueous solution, ).

The ceramic-like binder may be a nanoparticle size dispersed in water or a nanoparticle size in water. Examples of the ceramic-like binder include alumina, silica, zirconia, titania, ceramic powder such as titania or magnesia, ceramic sol or pseudo-boehmite can be mentioned.

In the present invention, the total content of the inorganic binder is not particularly limited and may be, for example, 5 to 20 parts by weight, and preferably 5 to 15 parts by weight, based on the total weight of the absorbent. If the content of the support is less than 5 parts by weight, the effect of improving the flowability is insignificant. If the content exceeds 20 parts by weight, the flowability of the absorbent may be deteriorated due to excessive repulsive force between the particles.

The carbon dioxide absorbent of the present invention can be used as an absorbent for a fluidized bed, and the absorbent used preferably has an average particle size of 40 to 200 占 퐉 and a particle distribution of 30 to 500 占 퐉 in order to reduce physical abrasion (abrasion) . If the average particle size is less than 40 탆, the dispersibility may be deteriorated. If the average particle size exceeds 200 탆, the physical abrasion may be increased. If the particle size is less than 30 탆, The absorption capacity may be decreased due to the reduced specific surface area, and if it exceeds 400 탆, the strength of the absorbent may be decreased to increase the wear resistance. The particle shape, average particle size, particle distribution, etc. of the absorbent may be prepared by spray drying as described below, but the present invention is not limited thereto.

The present invention also provides a method of producing a carbonaceous material, comprising: (A) drying a slurry comprising a carbon dioxide absorbent raw material and a solvent to form a core layer in a powder form; (B) forming a coating layer containing precipitated carbonate on the core layer; And (C) drying and firing the core layer and the coating layer.

The raw material used in the present invention may contain 30 to 50 parts by weight of the active ingredient and 50 to 70 parts by weight of the support, and may further include 5 to 70 parts by weight of the inorganic binder. At this time, the kind and content of the active ingredient, the support, and the inorganic binder are as described above.

The step (A) of preparing the slurry is a step of drying a slurry containing a carbon dioxide absorbent raw material and a solvent to form a powdery core layer. The solvent used in the step A) is not particularly limited, . The solid content of the raw material (hereinafter, referred to as a solid raw material) is not particularly limited. For example, the content of the solid raw material may be 30 to 40 parts by weight based on the total weight of the slurry. When the content of the solid raw material is less than 30 parts by weight, the viscosity of the slurry is low, so that it is not possible to produce a powdery sorbent having a desired particle size in the preparation of the powdery sorbent of the step (B) If the amount exceeds 40 parts by weight, the viscosity of the slurry increases sharply, so that it is impossible to prepare a powdery sorbent powder having a desired particle size in the preparation of the powdery sorbent of the step (B) to be described later, And it may not be possible to produce an absorbent having a desired shape.

In the present invention, the slurry in the step (A) may further include at least one additive selected from the group consisting of a dispersing agent, a defoaming agent and an organic binder. At this time, the dispersant, antifoaming agent and organic binder are added to control the homogenization of the solid raw material, the concentration of the slurry, the viscosity, stability, fluidity, strength or density and the like.

The dispersant is used to control the pH of the slurry, charge, dispersion and agglomeration of the surface of the slurry, thereby increasing the concentration of the slurry. The dispersant is anionic, nonionic, cationic, And amphoteric or zwitterionic dispersants may be used. Preferably, an anionic dispersant having good compatibility may be used. For example, a polycarboxylate anion system such as a poly carboxylate ammonium salt, an amine polycarboxylate salt, Surfactants, naphthalene formalin condensed sulfonate salts, sodium silicate, fatty acid polyhydric alcohols, and fluorosurfactants. The content of such a dispersant is not particularly limited, but may be 0.1 to 10 parts by weight, preferably 0.5 to 10 parts by weight, based on 100 parts by weight of the solid raw material.

The defoaming agent may be used to inhibit or remove bubbles which may occur during the production of the slurry, and the kind of the defoaming agent is not particularly limited. The antifoaming agent may include at least one selected from the group consisting of silicone, metal soap, amide, polyether, polyester, polyglycol, organic phosphoric acid and alcohol, A metal soap system and a polyester-based nonionic surfactant can be used. The content of the defoaming agent is not particularly limited, but 0.001 to 0.1 part by weight can be used for 100 parts by weight of the solid raw material.

The organic binder provides plasticity and fluidity to the slurry and ultimately imparts strength to the sorbent granules to facilitate handling of the granules prior to pre-drying and firing. For example, at least one selected from the group consisting of polyvinyl alcohol (PVA), polyethylene glycol (PEG), and methylcelluloses. More specifically, modified polyethylene glycol having a low viscosity (Sannopco HS-BD-20A, 45%, viscosity 800 cps, pH 8, specific gravity 0.99) can be used. The content of the organic binder is not particularly limited, but may be 0.5 to 5 parts by weight based on 100 parts by weight of the solid raw material.

Further, in the present invention, the step (A) may further include a step of pulverizing the particles in the slurry before drying the slurry. More specifically, the pulverization is a process for pulverizing particles in a mixture of a solid raw material and a solvent. The pulverization may be carried out using an air-jet mill, a roller mill, a ball mill, an attrition mill ), A vibratory mill, a planetary mill, a bead mill, etc., and it is preferable to crush the particles in the slurry to a few microns (탆) or less . By this step, the pulverized particles are more homogeneously dispersed in the slurry and the aggregation of the particles in the slurry is suppressed by the added dispersant, so that a homogeneous and stable slurry can be produced.

If necessary, the pulverization step can be repeated several times, and the fluidity of the slurry can be controlled by adding a dispersant and defoaming agent between each pulverization step. In addition, an organic binder may be added to maintain the particle shape during spray drying. On the other hand, if the solid raw material particles are several microns or less, the wet grinding process may be omitted.

In the present invention, the step (A) may further include removing foreign substances in the slurry before drying the slurry. Through the above steps, it is possible to remove foreign matters and agglomerated raw materials that may cause nozzle clogging or the like during spray molding. The removal of the foreign matter can be performed by sieving using a sieve.

In the present invention, the drying method in the step (A) is not particularly limited, but it is possible to form the slurry into powder form, for example, by spray drying. The spray drying can be carried out using a conventional spray dryer, and the spraying method and the operating conditions of such a spray dryer can be applied to those generally used in this field. As a specific spraying method, a countercurrent spraying method in which a pressurizing nozzle is sprayed in a direction opposite to the flow of the drying air can be used.

In the step (A), the powdery core layer may be spray-dried at an air temperature of 180 to 200 ° C at a slurry feed rate of 10 to 15 liters / hr. When the above-mentioned temperature of the powdery core layer is outside the range of the air temperature and the slurry loading speed, the shape of the particles produced in the dryer may not be spherical and irregular shapes may be formed, thereby causing problems of wear and flowability of the particles.

The step (B) of the present invention is a step of forming a coating layer containing a precipitated carbonate on the core layer formed as described above, wherein a coating agent containing a precipitated carbonate is coated on the core layer formed in the step (A) can do. As a method of coating the coating agent, a commonly used coating method may be used without limitation. Preferably, the coating layer can be formed on the core layer through spray drying. At this time, the spray drying method may be applied to the spray drying method in the step (A).

A preferred method for forming a coating layer on the core layer in the present invention is a method in which a core layer in powder form is formed by spray drying in the step (A), and a coating agent containing a precipitated carbonate is sprayed onto the core layer A coating layer containing a precipitated carbonate can be formed.

The step (C) of drying and firing in the present invention is a step of drying the core layer and the coating layer obtained in the step (B), followed by firing to produce a carbon dioxide absorbent. The core layer and the coating layer obtained in the step (B) The carbon dioxide absorbent may be prepared by drying at 110 to 130 ° C for 2 to 24 hours, raising the temperature to 350 to 850 ° C at a rate of 1 to 5 ° C / min, and then firing the carbon dioxide absorbent for 2 to 10 hours. In step (C) If the drying condition is out of the above range, the moisture content of the particles may exceed the allowable limit and the caking may be deteriorated during storage. If the firing condition is exceeded, the strength of the particles may be deteriorated.

Also, the dispersant, defoamer, and organic binder injected during the production of the slurry through the above-described firing process are burned to bond the raw materials, thereby improving the strength of the particles.

In the meantime, the present invention provides a carbon dioxide absorbing apparatus comprising: a spray nozzle (1) installed inside a chamber (10) for spraying a raw material supplied from a carbon dioxide absorbent raw material supply unit; A high temperature drying blower 3 installed at one side of the chamber 10 to blow hot air into the chamber 10; A powder collecting device (4) installed at a lower portion of the chamber (10) and collecting the powder; And a coating spray nozzle (2) installed in the chamber (10) for spraying a coating agent containing precipitated carbonate.

Hereinafter, the spray drying apparatus of the present invention will be described in more detail with reference to the accompanying drawings.

1 is a cross-sectional view of a spray drying apparatus according to a preferred embodiment of the present invention.

Referring to FIG. 1, a spray drying apparatus according to the present invention includes a spray nozzle 1 installed inside a chamber 10 for spraying a raw material supplied from a carbon dioxide absorbent raw material supply unit; A high temperature drying blower 3 installed at one side of the chamber 10 to blow hot air into the chamber 10; A powder collecting device (4) installed at a lower portion of the chamber (10) and collecting the powder; And a coating spray nozzle 2 disposed above the chamber 10 for spraying a coating agent containing precipitated carbonate.

In the present invention, in order to increase the residence time of the sprayed particles in the spray dryer, it is preferable that the spray nozzle is installed at a position satisfying the following general formula (1). If the coating spray nozzle is out of the above range, the residence time in the spray drying apparatus is shortened, so that the coating effect of the precipitated carbonate can be reduced. In addition, although the spray nozzle may be elongated and injected deep into the spray drying apparatus, the spray nozzle may be coated with slurry to act as an impurity.

≪ General Formula 1 &

In this formula,

D represents the length of the cross section of the chamber,

and d represents the length from the outer circumferential surface of the chamber to the coating spray nozzle.

The present invention also provides a method for reducing carbon dioxide comprising contacting a carbon dioxide-containing gas with a carbon dioxide sorbent according to the present invention.

The carbon dioxide-containing gas may be an exhaust gas, a syngas, or a fuel gas. In the present invention, carbon dioxide may be removed from the exhaust gas, the syngas or the fuel gas.

10 parts by weight of potassium carbonate, 20 parts by weight of bentonite as a support, and 70 parts by weight of distilled water were mixed well and then made into a slurry of several micro-sizes using a ball mill composed of balls having a size of 0.1 mm. Then, the slurry prepared above was spray-dried at a temperature of 180 to 200 ° C. at a rate of 10 to 15 liter / hr using a spray drier, and d / D (D: length of the cross section of the chamber, d: The length from the outer circumferential surface to the coating spray nozzle) was 1/8, the precipitated carbonate was injected into the spray dryer in spray form to prepare a powdery sorbent coated with precipitated carbonate.

At this time, the amount of the precipitated carbonate was set to 5 parts by weight with respect to the solid content of the slurry to be spray-dried. The powdery absorbent coated with the precipitated carbonate prepared above was heated in a furnace at a heating rate of 5 DEG C / min to 650 DEG C And then fired for 2 hours or more to prepare a carbon dioxide absorbent.

A carbon dioxide absorbent was prepared in the same manner as in Example 1 except that the precipitated carbonate introduced at the top of the spray dryer was added in an amount of 1 part by weight based on the solid content of the slurry spray-dried.

[Comparative Example 1]

A carbon dioxide absorbent was prepared in the same manner as in Example 1, except that no precipitated carbonate was added.

[Test Example]

The powder characteristics of the carbon dioxide absorbent prepared in Examples 1 and 2 and Comparative Example 1 were measured and are shown in Table 1 below.

(1) Measurement of powder characteristics (cake characteristics)

Into a container made of stainless steel, 50 g of the carbon dioxide absorbent prepared according to the above Examples and Comparative Examples was put and covered with a lid, and then the mixture was pressurized for 30 minutes using a weight of 30 kg. The carbon dioxide absorbent pressed in the form of a cake was put on a vibration screener (screener hole diameter: 200 micrometers) and allowed to stand for 30 minutes. Then, the amount of the absorbent remaining on the vibration screener was measured.

division Precipitated carbonate
input Caking characteristics of powders
(Vibration screener 30 minutes
The amount of absorbent remaining after driving) Example 1 5 parts by weight 5.2 g Example 2 1 part by weight 10.3 g Comparative Example 1 - 38.2g

As shown in Table 1, in the case of Examples 1 and 2 including a coating layer containing a precipitated carbonate, the caking characteristics of the powder of the absorbent were improved as compared with Comparative Example 1 containing no precipitated carbonate Respectively.

Claims (23)

A core layer on which an active component capable of reacting with carbon dioxide is supported in a support; And
And a coating layer surrounding the core layer and containing precipitated carbonate.
delete The method according to claim 1,
Wherein the support comprises at least one selected from the group consisting of ceramics, natural or synthetic zeolites, diatomaceous earth and carbon bodies.
The method according to claim 1,
Wherein the core layer further comprises an inorganic binder.
5. The method of claim 4,
Wherein the inorganic binder comprises at least one selected from the group consisting of calcium silicate, calcium aluminate, bentonite, kaolin, alumina sol, silica sol and pseudoboehmite.
The method according to claim 1,
Wherein the average particle size of the absorbent is 40 to 200 占 퐉 and the particle distribution is 30 to 500 占 퐉.
The method according to claim 1,
Wherein the precipitated carbonate is 2 to 6 parts by weight based on the total weight of the absorbent.
(A) drying a slurry comprising a carbon dioxide absorbent raw material and a solvent to form a powdery core layer;
(B) forming a coating layer containing precipitated carbonate on the core layer; And
(C) drying the core layer and the coating layer, and then firing the carbon dioxide absorbent.
9. The method of claim 8,
Wherein the raw material comprises 30 to 50 parts by weight of the active ingredient and 50 to 70 parts by weight of the support.
10. The method of claim 9,
Wherein the raw material further comprises 5 to 70 parts by weight of an inorganic binder.
delete 9. The method of claim 8,
Wherein the solid content of the raw material is 30 to 40 parts by weight based on the total weight of the slurry in the step (A).
9. The method of claim 8,
In the step (A), the slurry further comprises at least one additive selected from the group consisting of a dispersing agent, a defoaming agent and an organic binder.
9. The method of claim 8,
Wherein the step (A) further comprises grinding the particles in the slurry before drying the slurry.
9. The method of claim 8,
Wherein the step (A) further comprises removing foreign matter in the slurry before drying the slurry.
9. The method of claim 8,
Wherein the powdery core layer is spray dried at a slurry feed rate of 10 to 15 liters / hr at an air temperature of 180 to 200 ° C in the step (A).
17. The method of claim 16,
Wherein the step (B) comprises adding a coating agent containing a precipitated carbonate during the spray drying to form a coating layer.
9. The method of claim 8,
Wherein the drying temperature is from 110 to 130 캜 and the drying time is from 2 to 24 hours in the drying and firing step (C).
9. The method of claim 8,
In the drying and firing step (C), the firing is carried out for 2 to 10 hours after raising the powdery sorbent to 350 to 850 ° C at a rate of 1 to 5 ° C / min.
A spray nozzle 1 installed in the chamber 10 for spraying a raw material supplied from a carbon dioxide absorbent material supply part;
A high temperature drying blower 3 installed at one side of the chamber 10 to blow hot air into the chamber 10;
A powder collecting device (4) installed at a lower portion of the chamber (10) and collecting the powder; And
And a coating spray nozzle (2) installed in the chamber (10) for spraying a coating agent containing precipitated carbonate.
21. The method of claim 20,
Wherein the coating spray nozzle is installed at the top of the chamber and the position thereof satisfies the following general formula (1).
≪ General Formula 1 &

In this formula,
D represents the length of the cross section of the chamber,
and d represents the length from the outer circumferential surface of the chamber to the coating spray nozzle.
A method for reducing carbon dioxide, comprising contacting a gas containing carbon dioxide with a carbon dioxide absorbent according to claim 1.
23. The method of claim 22,
Wherein the gas containing carbon dioxide is a flue gas, a syngas or a fuel gas.

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