KR101644538B1 - Method and apparatus for capturing and resourcing carbon dioxide from flue gas containing carbon dioxide - Google Patents

Abstract

The present invention relates to a method and apparatus for collecting and recycling carbon dioxide from an exhaust gas containing carbon dioxide, and more particularly, to a method and apparatus for collecting carbon dioxide from an exhaust gas containing carbon dioxide The present invention relates to a method and an apparatus for collecting and recycling carbon dioxide from an exhaust gas containing carbon dioxide which can recycle captured carbon dioxide.

Description

TECHNICAL FIELD [0001] The present invention relates to a method and apparatus for collecting and recycling carbon dioxide from an exhaust gas containing carbon dioxide,

The present invention relates to a method and apparatus capable of simultaneously collecting and recycling carbon dioxide from an exhaust gas containing carbon dioxide.

Recently, various efforts have been made to reduce GHG emissions in relation to global warming. Carbon Capture & Storage (CCS) is the concept of using green energy such as hydrogen energy, increasing thermal efficiency, and capturing and storing CO ₂ emitted by more aggressive methods.

The CO ₂ trapping technology can be largely classified into the absorption method, the adsorption method, and the membrane separation method. The absorption method is considered to be the closest to commercialization, and the absorption method mainly uses an amine-based absorbent or an ammonia-based absorbent. Depending on the nature of the process, the composition of the process is slightly different, and the economics of the CO ₂ capture facility are largely determined by the steam energy used to regenerate the absorbent.

On the other hand, recycling technology using a CO ₂ is the achieve the state etc. formate (formic acid), DMC (dimethyl carbonate), the carbonate prepared (CaCO _3, NaHCO _3), generally if the formic acid and the DMC has a collecting CO ₂ It is refined to increase purity, remove impurities, and then use it in the process.

One aspect of the present invention is to provide a method and apparatus for collecting carbon dioxide and collecting carbon dioxide from an exhaust gas containing carbon dioxide, which is able to collect carbon dioxide from the exhaust gas containing carbon dioxide and collect the collected carbon dioxide.

Another aspect of the present invention is to provide a method and apparatus for collecting and reusing carbon dioxide, which is capable of recycling carbon dioxide by discharging carbon dioxide without using steam energy, instead of a regeneration tower for separating and discharging carbon dioxide using conventional steam energy .

According to an embodiment of the present invention, there is provided a method for purifying carbon dioxide, comprising: supplying an exhaust gas containing carbon dioxide to an absorption tower; supplying ammonia water to an absorption tower to absorb carbon dioxide contained in the exhaust gas; Discharging the carbon dioxide-absorbed ammonia water, and supplying the carbon dioxide-containing ammonia water to the carbon monoxide bath reactor and the water separator; Reacting the carbon dioxide-absorbed ammonia water with the NaCl supplied from the concentrating column to form NH ₄ Cl and NaHCO ₃ ; NH ₄ Cl formed in the neutralization reactor is supplied to an elution reactor and reacted with a calcium compound to elute Ca ²⁺ to form a mixed solution of Ca ^{2 +} , NH ₄ ⁺ , Cl ^- and OH ^- ; Decomposing ammonia water in which carbon dioxide has been absorbed in the water separator into ammonia water and carbon dioxide, and supplying the carbon dioxide to a carbonation reactor; In the carbonation reactor, Ca ^{2 +} , NH ^{4 +} , Cl ^- and OH ^- supplied from the elution reactor; Carbon dioxide supplied from the water separator; And NaOH; Forming CaCO ₃ in the carbonation reactor; Transporting NH ₄ ⁺ , Cl ^- , and Na ⁺ supplied from the carbonation reactor to a concentrating tower; And steam in the concentrating tower to form CO ₂ , NH ₃ , H ₂ O, and NaCl, supplying the CO ₂ , NH _3, and H ₂ O to the water separator, and supplying the NaCl to the neutralization reactor; And a method for collecting and recycling carbon dioxide from an exhaust gas containing carbon dioxide.

The calcium compound is preferably provided from at least one member selected from the group consisting of slag, waste concrete, fly ash, flooring, paper slag, calcite, Ca (OH) ₂ , CaCl ₂ and CaO.

The step of supplying the carbon dioxide to the carbonation reactor is preferably a step of supplying the carbon dioxide and the ammonia water absorbed by the carbon dioxide to the carbonation reactor together.

It is preferable that the ammonia water absorbed by the carbon dioxide separator is decomposed into ammonia water and carbon dioxide in the water separator, and the carbon dioxide is supplied to the carbonation reactor and the heavier regenerator.

And supplying the carbon dioxide-absorbed ammonia water discharged from the absorption tower to the carbon dioxide reactor.

Another embodiment of the present invention is an apparatus for capturing and collecting carbon dioxide by using ammonia water as an absorbing liquid from an exhaust gas containing carbon dioxide, which absorbs carbon dioxide from the carbon dioxide-containing exhaust gas into ammonia water and absorbs the carbon dioxide- tower; A buffer tank for supplying carbon dioxide-absorbed ammonia water discharged from the absorption tower and reacting the NaCl supplied from the concentrating tower with the ammonia water absorbed therein to form NaHCO ₃ and NH ₄ Cl; An elution reactor for reacting the NH ₄ Cl supplied from the neutralization reactor with a calcium compound; Ca ^{2 +} , NH ₄ ⁺ , Cl ^- and OH ^- supplied from the elution reactor; Carbon dioxide supplied from the water separator; And a NaOH to form CaCO ₃ ; NH ₄ ⁺ , Cl ^- and Na ⁺ supplied from the carbonation reactor are added with steam to form CO ₂ , NH ₃ , H ₂ O and NaCl, and the CO ₂ , NH ₃ and H ₂ O are supplied A concentrating tower for supplying the NaCl to the azeotrope reactor; And ammonia water having absorbed carbon dioxide from the absorption tower is supplied and CO ₂ , NH ₃ and H ₂ O are supplied from the condensation column, the ammonia water absorbed by the carbon dioxide is decomposed into ammonia water and carbon dioxide, and the carbon dioxide is supplied to the carbonation reactor And a water separator for supplying carbon dioxide-removed ammonia water to the absorption tower, wherein the carbon dioxide-containing exhaust gas contains carbon dioxide.

The calcium compound is preferably provided from at least one member selected from the group consisting of slag, waste concrete, fly ash, flooring, paper slag, calcite, Ca (OH) ₂ , CaCl ₂ and CaO.

Preferably, the water separator supplies the carbon dioxide and the ammonia water absorbed in the carbon dioxide to the carbonation reactor together.

Preferably, the water separator supplies carbon dioxide to the regeneration reactor.

Preferably, the absorption tower supplies ammonia water having absorbed carbon dioxide to the carbonation reactor.

By using the method and apparatus for capturing and recycling carbon dioxide from the exhaust gas containing carbon dioxide of the present invention, carbon dioxide capture and resource conversion can be performed at the same time.

In addition, since the carbon dioxide used in the conventional carbon dioxide capture process using ammonia water can be collected and the carbon dioxide can be recycled without using the steam energy supplied to the regeneration tower for regenerating the ammonia water, it can be advantageous in terms of economy.

In addition, it is possible to obtain byproducts such as CaCO ₃ and NaHCO ₃ from carbon dioxide, and it is applicable to a carbon dioxide emission source, such as a power plant, a steelworks, etc., in which resources can be utilized and a carbon dioxide capture process using ammonia water can be applied.

1 is a schematic diagram showing a conventional carbon dioxide capture process.
2 is a schematic diagram showing an apparatus for collecting and recycling carbon dioxide from an exhaust gas containing carbon dioxide according to an embodiment of the present invention.
3 is a schematic view showing an apparatus for collecting and recycling carbon dioxide from an exhaust gas containing carbon dioxide according to another embodiment of the present invention.
4 is a schematic view showing an apparatus for collecting and recycling carbon dioxide from an exhaust gas containing carbon dioxide according to another embodiment of the present invention.

Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. However, the embodiments of the present invention can be modified into various other forms, and the scope of the present invention is not limited to the embodiments described below. Further, the embodiments of the present invention are provided to more fully explain the present invention to those skilled in the art.

FIG. 1 is a schematic view showing a conventional carbon dioxide capture process, and FIGS. 2 and 3 are schematic views showing an apparatus for capturing and collecting carbon dioxide from an exhaust gas containing carbon dioxide according to an embodiment of the present invention.

An embodiment of the present invention is an apparatus for collecting and recycling carbon dioxide using ammonia water as an absorption liquid from an exhaust gas containing carbon dioxide, comprising: an absorption tower for absorbing carbon dioxide from ammonia water from a carbon dioxide-containing exhaust gas and discharging the ammonia water ; A buffer tank for supplying carbon dioxide-absorbed ammonia water discharged from the absorption tower and reacting the NaCl supplied from the concentrating tower with the ammonia water absorbed therein to form NaHCO ₃ and NH ₄ Cl; An elution reactor for reacting the NH ₄ Cl supplied from the neutralization reactor with a calcium compound; Ca ^{2 +} , NH ₄ ⁺ , Cl ^- and OH ^- supplied from the elution reactor; Carbon dioxide supplied from the water separator; And a NaOH to form CaCO ₃ ; NH ₄ ⁺ , Cl ^- and Na ⁺ supplied from the carbonation reactor are added with steam to form CO ₂ , NH ₃ , H ₂ O and NaCl, and the CO ₂ , NH ₃ and H ₂ O are supplied A concentrating tower for supplying the NaCl to the azeotrope reactor; And ammonia water having absorbed carbon dioxide from the absorption tower is supplied and CO ₂ , NH ₃ and H ₂ O are supplied from the condensation column, the ammonia water absorbed by the carbon dioxide is decomposed into ammonia water and carbon dioxide, and the carbon dioxide is supplied to the carbonation reactor And a water separator for supplying carbon dioxide-removed ammonia water to the absorption tower, wherein the carbon dioxide-containing exhaust gas contains carbon dioxide.

According to another embodiment of the present invention, there is provided a method for purifying carbon dioxide, comprising: supplying an exhaust gas containing carbon dioxide to an absorption tower, supplying ammonia water to an absorption tower to absorb carbon dioxide contained in the exhaust gas; Discharging the carbon dioxide-absorbed ammonia water, and supplying the carbon dioxide-containing ammonia water to the carbon monoxide bath reactor and the water separator; Reacting the carbon dioxide-absorbed ammonia water with the NaCl supplied from the concentrating column to form NH ₄ Cl and NaHCO ₃ ; By reacting a calcium compound eluted with Ca ^{2 +} NH ₄ Cl formed by supplying sodium bicarbonate in the reaction vessel with the dissolution ^{_{reactor, Ca 2 +, NH 4 +}} , Cl - and OH ^- to form a mixture of; Decomposing ammonia water in which carbon dioxide has been absorbed in the water separator into ammonia water and carbon dioxide, and supplying the carbon dioxide to a carbonation reactor; In the carbonation reactor, Ca ^{2 +} , NH ₄ ⁺ , Cl ^- and OH ^- supplied from the elution reactor; Carbon dioxide supplied from the water separator; And NaOH; Forming CaCO ₃ in the carbonation reactor; Transporting NH ₄ ⁺ , Cl ^- , and Na ⁺ supplied from the carbonation reactor to a concentrating tower; And steam in the concentrating tower to form CO ₂ , NH ₃ , H ₂ O, and NaCl, supplying the CO ₂ , NH _3, and H ₂ O to the water separator, and supplying the NaCl to the neutralization reactor; And a method for collecting and recycling carbon dioxide from an exhaust gas containing carbon dioxide.

Specifically, the exhaust gas containing carbon dioxide is supplied to the top of the absorption tower, and the step of removing carbon dioxide is performed. In the absorption tower, carbon dioxide is absorbed as the absorption liquid from the carbon dioxide-containing exhaust gas by the chemical absorption method. The absorption liquid is not particularly limited, but it is preferable to use chemically stable aqueous ammonia. The ammonia water having absorbed the carbon dioxide is discharged from the lower part of the absorption tower, and the exhaust gas from which carbon dioxide has been removed moves to the upper part of the absorption tower and is discharged.

Then, the ammonia water that has absorbed the carbon dioxide discharged from the lower part of the absorption tower can be transferred to the water separator and the intermediate-tank reactor, respectively. First, the ammonia water having absorbed carbon dioxide transferred to the above-mentioned regeneration reactor contains NH ₄ HCO ₃ , and reacts with NaCl supplied from the concentrating column to form NaHCO ₃ and NH ₄ Cl. The NaHCO ₃ is available as a high value added resource, and the NH ₄ Cl is transferred to the elution reactor. Further, additional carbon dioxide can be supplied to the above-described regeneration reactor.

In the elution reactor, the calcium compound supplied from the calcium supply unit reacts with the calcium compound. At this time, the calcium compound is not particularly limited as long as it is a substance containing calcium, and it is preferable that the calcium compound includes at least one of Ca (OH) ₂ , CaO and CaCl ₂ . In addition, the calcium compound is preferably provided from at least one selected from the group consisting of slag, waste concrete, fly ash, flooring, paper slag and calcite, but is not limited thereto.

Meanwhile, Ca ²⁺ , NH ^{4 +} , Cl ^-, and OH ^- , including Ca ^{2 +} ions selectively extracted from the elution reactor, are supplied to the carbonation unit. At this time, carbon dioxide is supplied from the water separator to the carbonation reactor, and NaOH can be supplied from the NaOH supply unit. Thereafter, in the carbonation reactor, CaCO ₃ is formed through carbonation, and the CaCO ₃ can be obtained and utilized as a resource.

At this time, in addition to carbon dioxide provided from the water separator, ammonia water and carbon dioxide-containing ammonia water may be further supplied. That is, in the conventional carbon dioxide collecting apparatus, unlike the process of producing high purity carbon dioxide in gaseous form by simply collecting carbon dioxide discharged by applying steam energy to the regenerator, it is not necessary to produce carbon dioxide in a gaseous form, , A solution in which ammonia water and carbon dioxide-containing ammonia water, which are components other than carbon dioxide, are mixed, can be used in a carbonation reactor or a heavier reactor. That is, since separate steam energy for separating carbon dioxide and ammonia water from the water separator is not required, it is possible to exhibit an excellent effect in terms of energy efficiency.

Meanwhile, NH ₄ ⁺ , Cl ^- and Na ⁺ discharged from the carbonation reactor are transferred to a concentrating column, and CO ₂ , NH ₃ and H ₂ O can be transferred to the separator by adding steam energy to the concentrating column . In addition, NaCl is discharged to the lower end of the concentrating tower and can be utilized to react with the carbon dioxide-containing ammonia water in the bath reactor.

By the steam energy applied to the concentrating tower, the temperature in the concentrating tower represents a temperature range of about 100 ° C., and CO ₂ , NH ₃ and H ₂ O transferred to the water separator are in the form of vapor at about 95 ° C. Lt; / RTI > Accordingly, in the water separator, a part of the carbon dioxide-containing ammonia water supplied from the absorption tower can be separated into carbon dioxide and ammonia water by heat in the form of steam supplied from the concentration column, and the separated carbon dioxide is again transferred to the carbonation reactor, It is used to form CaCO ₃ . That is, in the water separator, ammonia water, which is absorbed by the heat supplied from the concentration tower, is decomposed into ammonia water and carbon dioxide, or carbon dioxide generated by separating the ammonia, water vapor, and carbon dioxide supplied from the concentration tower can be supplied to the carbonation reactor have. Further, as described above, the ammonia water or the carbon dioxide-containing ammonia water generated in the water separator can be supplied to the absorption tower without separate steam energy treatment and can be used for collecting the carbon dioxide.

In addition, in addition to supplying carbon dioxide, carbon dioxide or carbon dioxide-absorbed ammonia water to the carbon dioxide reactor, the carbon dioxide separator may be further supplied with the ammonia water absorbed by the carbon dioxide or the carbon dioxide and carbon dioxide to the siloxane reactor. Further, the ammonia water absorbed from the bottom of the absorption tower can be used as a reactant in the carbonation reaction by directly supplying the ammonia water not only to the azeotropic reactor but also to the carbonation reactor.

Hereinafter, the present invention will be described more specifically by way of specific examples. The following examples are provided to aid understanding of the present invention, and the scope of the present invention is not limited thereto.

< Example >

2 is a schematic diagram of an apparatus for collecting and collecting carbon dioxide from an exhaust gas containing carbon dioxide according to an embodiment of the present invention. 2, an exhaust gas 201 containing carbon dioxide is supplied to the lower end of the absorption tower 101, and ammonia water is supplied to the upper end of the absorption tower 101 to remove carbon dioxide 201 contained in the exhaust gas. Respectively. Thereafter, the ammonia water 202, 215 in which the carbon dioxide was absorbed was supplied to the auxiliary reactor 102, the water separator 108, and the carbon dioxide reactor 106, respectively. The ammonia water 202 absorbed by the carbon dioxide was reacted with the NaCl 205 supplied from the concentration tower 103 to form NH ₄ Cl 204 and NaHCO ₃ and the NaHCO ₃ .

Then, the NH ₄ Cl (204) was supplied to the elution reactor (104), reacted with the slag containing the calcium component supplied from the calcium supplier (105), and then the effluent was transferred to the carbonation reactor (106). In the carbonation reactor 106, NaOH supplied from the NaOH supply unit 107, carbon dioxide 207 supplied from the water separator 108, and ammonia water containing carbon dioxide are reacted together to form CaCO ₃ through carbonation, This was obtained.

On the other hand, NH ₄ ⁺ , Cl ^- and Na ⁺ 206 were transferred from the carbonation reactor 106 to the concentrating column 103 and the internal temperature was increased to about 105 ° C. by adding steam energy 212, The CO ₂ , NH ₃ and H ₂ O 208 formed in the concentrating tower 103 were fed to the separator 108 and the NaCl 205 was fed to the beaker reactor 102, respectively.

At this time, the internal temperature of the water separator 108 may be about 70 ° C or so in a state in which no steam energy 212 'is applied as in the conventional carbon dioxide capture process shown in FIG. 1, The carbon dioxide-containing ammonia water can be decomposed into carbon dioxide and ammonia water, and the carbon dioxide 207 and the carbon dioxide-containing ammonia water generated at the upper end of the water separator 108 are supplied to the carbonation reactor 106 and utilized for the carbonation reaction.

It can be seen that carbon dioxide contained in the flue gas can be collected and the NaHCO ₃ and CaCO ₃ can be simultaneously obtained as a usable resource through the method of collecting and recycling carbon dioxide from the flue gas containing the carbon dioxide of the above embodiment have.

In addition, it can be confirmed that carbon dioxide can be collected and recycled without supplying steam energy separately from the water separator, and thereby, compared with the case where the steam energy 212 'is essentially used in the conventional regenerator, It can be confirmed that the operation is possible.

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, but, on the contrary, It will be obvious to those of ordinary skill in the art.

101, 101 ': absorption tower 102: a neutralization reactor
103, 103 ': Condensation column 104: Elution reactor
105: calcium supply part 106: carbonation reactor
107: NaOH supply unit 108:
109, 109 ': Heat exchanger 110: Reclaiming tower
201, 201 ': Carbon dioxide-containing flue gas
202, 202 ', 211, 215: carbon dioxide-containing ammonia water
203, 203 ': Flue gas 204: NH ₄ Cl
205: NaCl 206: NH ₄ ⁺ , Cl ^- , Na ⁺
207: carbon dioxide 208, 208 ': CO ₂ , NH ₃ , H ₂ O
209, 209 ', 210, 210': Ammonia water
212, 212 ', 213, 213': Steam energy
214, 214 ': Washing water 216, 217: Ammonia water

Claims (10)

Supplying an exhaust gas containing carbon dioxide to the absorption tower, and supplying ammonia water to the absorption tower to absorb carbon dioxide contained in the exhaust gas;
Discharging the carbon dioxide-absorbed ammonia water, and supplying the carbon dioxide-containing ammonia water to the carbon monoxide bath reactor and the water separator;
Reacting the carbon dioxide-absorbed ammonia water with the NaCl supplied from the concentrating column to form NH ₄ Cl and NaHCO ₃ ;
By reacting a calcium compound eluted with Ca ^{2 +} NH ₄ Cl formed by supplying sodium bicarbonate in the reaction vessel with the dissolution ^{_{reactor, Ca 2 +, NH 4 +}} , Cl - and OH ^- to form a mixture of;
Decomposing ammonia water in which carbon dioxide has been absorbed in the water separator into ammonia water and carbon dioxide, and supplying the carbon dioxide to a carbonation reactor;
In the carbonation reactor, Ca ^{2 +} , NH ₄ ⁺ , Cl ^- and OH ^- supplied from the elution reactor; Carbon dioxide supplied from the water separator; And NaOH;
Forming CaCO ₃ in the carbonation reactor;
Transporting NH ₄ ⁺ , Cl ^- , and Na ⁺ supplied from the carbonation reactor to a concentrating tower; And
Adding steam in the concentrating tower to form CO ₂ , NH ₃ , H ₂ O and NaCl, supplying the CO ₂ , NH ₃ and H ₂ O to the water separator, and supplying the NaCl to the neutralization reactor A method for collecting and recycling carbon dioxide from an exhaust gas containing carbon dioxide.
The method according to claim 1, wherein the calcium compound is provided from at least one selected from the group consisting of slag, waste concrete, fly ash, flooring, paper slag, calcite, Ca (OH) ₂ , CaCl ₂ and CaO, And collecting and recycling carbon dioxide.
The method according to claim 1, wherein the step of supplying the carbon dioxide to the carbonation reactor is a step of supplying the carbon dioxide and the ammonia water absorbed in the carbon dioxide together to the carbonation reactor, wherein the carbon dioxide is captured and collected from the exhaust gas containing carbon dioxide.
The method according to claim 1, wherein the carbon dioxide-absorbed ammonia water in the water separator is decomposed into ammonia water and carbon dioxide, and the carbon dioxide is supplied to a carbonation reactor and a sodium bicarbonate reactor.
The method according to claim 1, further comprising the step of supplying the carbon dioxide-absorbed ammonia water discharged from the absorption tower to a carbon dioxide reactor, and collecting and recycling carbon dioxide from the carbon dioxide-containing flue gas.
In an apparatus for capturing and collecting carbon dioxide using ammonia water as an absorption liquid from an exhaust gas containing carbon dioxide,
An absorption tower for absorbing carbon dioxide as ammonia water from the carbon dioxide-containing exhaust gas and discharging the ammonia water absorbed by the carbon dioxide;
A buffer tank for supplying carbon dioxide-absorbed ammonia water discharged from the absorption tower and reacting the NaCl supplied from the concentrating tower with the ammonia water absorbed therein to form NaHCO ₃ and NH ₄ Cl;
An elution reactor for reacting the NH ₄ Cl supplied from the neutralization reactor with a calcium compound;
Ca ²⁺ , NH ₄ ⁺ , Cl ^- and OH ^- supplied from the elution reactor; Carbon dioxide supplied from the water separator; And a NaOH to form CaCO ₃ ;
NH ₄ ⁺ , Cl ^- and Na ⁺ supplied from the carbonation reactor are added with steam to form CO ₂ , NH ₃ , H ₂ O and NaCl, and the CO ₂ , NH ₃ and H ₂ O are supplied A concentrating tower for supplying the NaCl to the azeotrope reactor; And
Ammonia water having absorbed carbon dioxide is supplied from the absorption tower, CO ₂ , NH ₃ and H ₂ O are supplied from the concentration column, the ammonia water absorbed by the carbon dioxide is decomposed into ammonia water and carbon dioxide, the carbon dioxide is supplied to the carbonation reactor And a water separator for supplying ammonia water from which carbon dioxide has been removed to an absorption tower, for collecting and recycling carbon dioxide from an exhaust gas containing carbon dioxide.
According to claim 6, wherein said calcium compound is a slag, recycled concrete, fly ash, bottom ash, paper making slag, _{calcite, Ca (OH) 2, CaCl} 2 , and carbon dioxide with the flue gas-containing is provided from at least one selected from the group consisting of CaO And collecting and recycling carbon dioxide.
The apparatus according to claim 6, wherein the water separator supplies the carbon dioxide and carbon dioxide-absorbed ammonia water together to a carbonation reactor, which collects and recovers carbon dioxide from the carbon dioxide-containing flue gas.
The apparatus according to claim 6, wherein the water separator supplies carbon dioxide to a regeneration reactor, which collects and recovers carbon dioxide from an exhaust gas containing carbon dioxide.
7. The apparatus according to claim 6, wherein the absorption tower supplies carbon dioxide-absorbed ammonia water to a carbonation reactor, which collects and recovers carbon dioxide from an exhaust gas containing carbon dioxide.

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