KR20150127532A - Method of manufacturing dry sorbents for high-temperature carbon dioxide capture based lithium silicate and dry sorbents for high-temperature carbon dioxide capture - Google Patents

Abstract

Regarding a manufacturing method of a lithium silicate-based high-temperature dry absorbent for removing carbon dioxide and a high-temperature dry absorbent, a manufacturing method comprises the steps of: forming a mixed raw material by mixing a lithium precursor, silicon oxide, and metal oxide; obtaining lithium silicate solid by drying the mixed raw material; and plasticizing the obtained lithium silicate solid.

Description

FIELD OF THE INVENTION [0001] The present invention relates to a method for manufacturing a dry silicate-based dry absorbent for high temperature, and a dry carbon dioxide dry absorbent for high temperature use. BACKGROUND OF THE INVENTION 1. Field of the Invention [0001]

The present invention relates to a method of manufacturing a dry siloxane-based dry absorbent for carbon dioxide removal and a carbon dioxide dry absorbent for high temperature. More specifically, the present invention relates to a dry carbon dioxide absorbent for high temperature use which is excellent in absorbability and regeneration for removing carbon dioxide from a power plant, A method for producing a dry absorbent, and a carbon dioxide dry absorbent for high temperature.

Gas, such as water vapor, clouds, carbon dioxide, methane, nitrous oxide, ozone, fluorine compounds (HFC, PFC, ClFC, SF6), is a greenhouse gas that affects climate change. Especially, carbon dioxide, methane, nitrous oxide, PFC and SF ₆ are the six gases to be regulated. Mainly carbon dioxide is a gas released into the atmosphere by the call of fossil fuels, and is known to be the most influential gas to climate change.

Methods for the recovery / storage of carbon dioxide are known such as absorption method, membrane separation method using gas separation, and adsorption method using zeolite adsorbent. However, this method is disadvantageous in that it has high energy consumption and high recovery cost, and it is difficult to treat a large amount of carbon dioxide. Recently, researches on a method using a dry regeneration absorbent for absorbing carbon dioxide have been carried out.

Lithium silicate, which is known as carbon dioxide dry absorbent at high temperature, has a disadvantage in that it absorbs carbon dioxide when it is used for a long time due to the growth of granules during the regeneration of carbon dioxide. In Japanese Patent Laid-Open No. 2003-62965, in order to overcome such disadvantages, an alkali metal carbonate and an aluminum oxide or an aluminum compound are added after the production of lithium silicate. However, in this method, after the step of calcining lithium carbonate and silica at about 700 DEG C to produce lithium silicate, the step of additionally adding alkali metal carbonate and aluminum oxide or aluminum compound is performed, that is, Is complicated.

In addition, lithium silicate exhibits a high carbon dioxide absorption capacity (under 100 vol% of carbon dioxide) of 24 to 28 wt% at 500 ° C to 550 ° C. However, lithium silicate has a high absorption capacity for carbon dioxide, but has a disadvantage in that the absorption rate is low and the absorption ability is deteriorated when it is used continuously.

An object of the present invention to solve the above problems is to provide a method and apparatus for recovering carbon dioxide and recovering carbon dioxide at a low temperature as compared with existing absorbents through a simple process, And a method for producing a dry absorbent.

It is another object of the present invention to provide a high temperature carbon dioxide dry absorbent.

There is provided a method for manufacturing a dry siloxane based high-temperature absorbent for removing carbon dioxide according to an embodiment of the present invention. The production method comprises the steps of mixing a lithium precursor, silicon oxide and a metal oxide to form a mixed raw material, drying the mixed raw material to obtain lithium silicate, and firing the obtained lithium silicate to form a dry absorbent for high temperature .

In one embodiment, the metal oxide may comprise aluminum oxide or zirconium oxide.

In one embodiment, the metal oxide may be gamma-aluminum oxide.

In one embodiment, the metal oxide may be 1 to 30% by weight based on the total weight of the mixed raw material.

In one embodiment, the mixing raw material may further comprise an alkali metal carbonate.

In one embodiment, the alkali metal carbonate may be 1 to 10% by weight based on the total weight of the mixed raw materials. Preferably, the alkali metal carbonate may be 1 to 5% by weight based on the total weight of the mixed raw materials.

In one embodiment, the lithium precursor may include lithium carbonate, lithium oxalate, lithium oxalate, lithium acetate or lithium nitrate.

In one embodiment, the lithium precursor may be lithium carbonate.

In one embodiment, the high-temperature dry absorbent may comprise lithium silicate (Li ₄ SiO ₄ ) and lithium metasilicate (Li ₂ SiO ₃ ).

A method for preparing a lithium silicate based high temperature dry sorbent for carbon dioxide removal according to an embodiment of the present invention comprises the steps of reacting a lithium precursor and silicon oxide to obtain lithium silicate (Li ₄ SiO ₄ ) Silicate (Li ₂ SiO ₃ ).

In one embodiment, the additive may be further mixed in the step of mixing the lithium metasilicate.

The dry silicate-based dry absorbent for carbon dioxide removal according to an embodiment of the present invention includes lithium silicate (Li ₄ SiO ₄ ) and lithium metasilicate (Li ₂ SiO ₃ ).

In one embodiment, the high-temperature dry absorbent may further comprise lithium aluminate and / or lithium zirconate.

In one embodiment, the high-temperature dry sorbent may further comprise a lithium-carbonate represented by LiMCO ₃ , wherein M represents potassium (K) or sodium (Na).

In one embodiment, the high-temperature dry absorbent comprises 3.6 to 5 moles of lithium (Li) per mole of silicon (Si) and 5 to 15 wt% of aluminum (Al) or zirconium (Zr) can do.

According to the method for producing a dry siloxane-based dry absorbent for carbon dioxide removal and the dry carbon dioxide dry absorbent for high temperature according to the present invention, a two-stage synthesis reaction in which lithium carbonate and silica are conventionally fired and then an alkali carbonate and an aluminum compound are further added thereto for firing , It is possible to easily produce a dry absorbent for high temperature through a one-step synthesis reaction. The dry absorbent for high temperature can recover and regenerate carbon dioxide in a high temperature range of 550 to 700 ° C., hardly exhibit aggregation phenomenon during the carbon dioxide absorption process, can maintain a high absorption capacity for carbon dioxide, It is advantageous that it can be regenerated at a temperature.

1 is a flow chart for explaining a process for producing a dry absorbent for high temperature according to an embodiment of the present invention.
2A is a graph showing the absorption ability of carbon dioxide of Samples 1-1 to 1-3 and Comparative Sample 1 according to an embodiment of the present invention.
2B is a graph showing the results of XRD analysis of samples 1-1 to 1-3 and Comparative Sample 1 before absorption of carbon dioxide according to an embodiment of the present invention.
2C is a diagram showing the results of regeneration evaluation of Samples 1-1 to 1-3 and Comparative Sample 1 according to the embodiment of the present invention.
3A is a graph showing the absorption ability of carbon dioxide in Samples 2-1 to 2-3 and Comparative Sample 2 according to an embodiment of the present invention.
FIG. 3B is a graph showing the results of XRD analysis of the sample 2-1 according to the embodiment of the present invention before, before and after the carbon dioxide absorption.
3C is a diagram showing a result of the regeneration evaluation of the sample 2-1 according to the embodiment of the present invention.
FIG. 3D is a scanning electron micrograph of Sample 2-1 and Comparative Sample 1 according to an embodiment of the present invention.
4A is a graph showing the absorption ability of carbon dioxide in Samples 3-1 and 3-2 according to an embodiment of the present invention.
4B is a graph showing carbon dioxide absorption rates of Samples 3-1 and 3-2 according to an embodiment of the present invention.
FIG. 4C is a graph showing the results of XRD analysis of samples 3-1 and 3-2 according to the embodiment of the present invention before, before and after absorption of carbon dioxide. FIG.
4D is a diagram showing the results of regeneration evaluation of Samples 3-1 and 3-2 according to the embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. The present invention is capable of various modifications and various forms, and specific embodiments are illustrated in the drawings and described in detail in the text. It is to be understood, however, that the invention is not intended to be limited to the particular forms disclosed, but on the contrary, is intended to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention. Like reference numerals are used for like elements in describing each drawing.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The singular expressions include plural expressions unless the context clearly dictates otherwise. In the present application, the term "comprises" or "having ", etc. is intended to specify that there is a feature, step, operation, element, part or combination thereof described in the specification, , &Quot; an ", " an ", " an "

Unless defined otherwise, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Terms such as those defined in commonly used dictionaries are to be interpreted as having a meaning consistent with the contextual meaning of the related art and are to be interpreted as either ideal or overly formal in the sense of the present application Do not.

1 is a flow chart for explaining a process for producing a dry absorbent for high temperature according to an embodiment of the present invention.

Referring to FIG. 1, a lithium precursor, silicon oxide, and a metal oxide are mixed to prepare a mixed raw material (Step S110).

The mixed raw materials can be prepared using a mortar and a mortar, and they can be prepared by uniformly mixing for 30 minutes to 1 hour.

Examples of the lithium precursor include lithium carbonate (Li ₂ CO ₃ ), lithium hydroxide (LiOH, LiOH H ₂ O), lithium oxalate, lithium acetate and lithium nitrate (LiNO ₃ ). These may be used independently or in combination of two or more.

Silicon oxide reacts with the lithium precursor at a constant molar ratio to produce lithium silicate (Li ₄ SiO ₄ ). By controlling the molar ratio of silicon oxide and lithium precursor, lithium metasilicate (Li ₂ SiO ₃ ) can be produced together with lithium silicate (Li ₄ SiO ₄ ).

Lithium carbonate (Li ₂ CO ₃ ), lithium hydroxide (LiOH, LiOH (LiOH), etc.) can be used as the lithium precursor of the present invention since silicon oxide and a metal oxide react with each other to produce lithium silicate (Li ₄ SiO ₄ ) H ₂ O) and lithium nitrate (LiNO ₃ ) are preferably used. It is more preferable to use lithium carbonate as a lithium precursor in terms of mass production in view of cost and ease of handling.

The metal oxide reacts with the lithium precursor to produce a lithium-metal oxide metal salt. As the lithium-metal oxide salt is produced, the molar ratio of the lithium precursor capable of reacting with silicon oxide changes, and lithium methasilicate (Li ₂ SiO ₃ ) can be maintained after regeneration. Lithium metalate and lithium metasilicate (Li ₂ SiO ₃ ) are inactive materials and can prevent the aggregation of lithium silicate (Li ₄ SiO ₄ ). That is, even if lithium silicate (Li ₄ SiO ₄ ), which is an active material produced by the reaction of lithium precursor and silicon oxide, is produced in large quantities, it is difficult to maintain its absorption ability during long-time driving due to grain growth or coagulation. The lithium metal salt produced by using the metal oxide as described above can be regenerated at a temperature lower than that of the conventional absorbent by alleviating the agglomeration phenomenon of lithium silicate (Li ₄ SiO ₄ ) generated at high temperature regeneration.

Examples of the metal oxide include aluminum oxide, zirconium oxide, and the like, including? -Oxide,? -Oxide and? -Oxide. These may be used alone or in combination of two or more.

When aluminum oxide is used as the metal oxide, lithium aluminate can be produced as a lithium-metal oxide metal salt. Alternatively, when zirconium oxide is used as the metal oxide, lithium zirconate can be produced as a lithium-metal oxide metal salt.

Aluminum oxide has a stable structure and does not react with lithium carbonate, so it may be difficult to produce lithium aluminate, and δ-aluminum oxide produces lithium aluminate more than α-aluminum oxide but less than γ-aluminum oxide . The γ-aluminum oxide and lithium carbonate are reacted with lithium carbonate in an amount of 1: 1 by the amount of γ-aluminum oxide added to produce lithium aluminate and reduce the reaction molar ratio of silicon oxide to lithium carbonate. Accordingly, in view of the fact that lithium silicate (Li ₄ SiO ₄ ) and lithium metasilicate (Li ₂ SiO ₃ ) coexist to generate a component that prevents cohesion of lithium silicate (Li ₄ SiO ₄ ) As the aluminum oxide, γ-aluminum oxide is preferable.

In order to produce lithium silicate (Li ₄ SiO ₄ ), the molar ratio of lithium precursor to silicon oxide may be 1: 1 to 5: 1. When the content of silicon oxide is larger than that of the lithium precursor, the amount of lithium silicate (Li ₄ SiO ₄ ) is decreased and the amount of lithium metasilicate (Li ₂ SiO ₃ ), which is an inactive material, There is a problem in that the performance of the apparatus is deteriorated. On the other hand, a lithium precursor and the 5 mole ratio of silicon oxide: if it exceeds 1, there is the unreacted lithium carbonate remains may be of the absorbent performance by reducing the amount of relatively lithium silicate (Li ₄ SiO ₄₎ . Thus, in order to produce lithium silicate (Li ₄ SiO ₄ ), the molar ratio of lithium precursor to silicon oxide can be 1: 1 to 5: 1, preferably 1.5: 1 to 3.5: 1, 1: 3: 1, and still more preferably 1.8: 1 to 2.5: 1. When the molar ratio of lithium carbonate to silicon oxide is lower than 2: 1, the structure of lithium metasilicate tends to increase relatively And most preferably 2: 1.

For example, a lithium carbonate and a metal oxide are reacted at a molar ratio of 1: 1 to form a lithium-metal oxide salt by reacting lithium carbonate and a metal oxide with a molar ratio of lithium carbonate to silicon oxide of 2: 1, The lithium carbonate is reduced to 1.7 mol to 1.85 mol. Accordingly, lithium-metal salt and lithium metasilicate (Li ₂ SiO ₃ ) can be produced simultaneously in the production of lithium silicate (Li ₄ SiO ₄ ).

The content of the metal oxide may be 1 to 30% by weight based on the total weight of the mixed raw materials. When the content of the metal oxide is less than 1% by weight, the amount of lithium-metal salt is decreased even though the amount of lithium silicate (Li ₄ SiO ₄ ) is increased. When the amount of lithium silicate is more than 30% by weight, (Li ₄ SiO ₄₎ the carbon dioxide absorption performance can be degraded by decreasing the content of. Preferably, the content of the metal oxide may be 3 to 20% by weight, more preferably 5 to 15% by weight based on the total weight of the mixed raw materials. For example, the content of the metal oxide may be 10% by weight based on the total weight of the mixed raw materials.

In one embodiment, when preparing the blended feedstock, an alkali metal carbonate may be added. That is, a lithium precursor, silicon oxide, a metal oxide and an alkali metal carbonate can be prepared as a raw material for mixing.

The alkali metal carbonate serves as a promoter for allowing lithium silicate (Li ₄ SiO ₄ ) and lithium metasilicate (Li ₂ SiO ₃ ) to coexist by reducing the reaction molar ratio between silicon oxide and lithium precursor. The content of the alkali metal carbonate may be 1 to 10% by weight based on the total weight of the mixed raw materials. If the content of the alkali metal carbonate exceeds 10% by weight, there arises a problem that the moisture absorptive capacity deteriorates due to eutectic melting. Preferably, the content of the alkali metal carbonate may be 5 wt% or less.

Examples of the alkali metal carbonate include potassium carbonate (K ₂ CO ₃ ) and sodium carbonate (Na ₂ CO ₃ ), and these may be used independently or in combination of two or more.

Subsequently, the mixed raw material prepared in step S110 is dried to obtain a lithium silicate solid (step S120).

For example, a mixed material is placed in an aluminum crucible and dried in an air atmosphere at a temperature of 100 ° C to 200 ° C for 1 to 10 hours under a heating furnace to obtain a lithium silicate solid. The solids can be obtained in various forms, such as in the form of a powder, in the form of a shaped body, or in the form of a film applied on a substrate.

By burning the lithium silicate solid, a dry absorbent for high temperature according to the present invention is prepared (step S130).

The firing process is performed in a manner that heat treatment is performed at a high temperature of 500 DEG C or more in an air atmosphere. The temperature of the firing process may be 700 ° C.

As described above, the dry product for high temperature, which is the final product according to the present invention, can be produced simply and stably by carrying out the synthesis reaction in the firing step using the mixed raw materials physically mixed.

At this time, the prepared dry absorbent for high temperature includes lithium silicate (Li ₄ SiO ₄ ), lithium metasilicate (Li ₂ SiO ₃ ) and lithium metalate. That is, lithium metasilicate (Li ₂ SiO ₃ ) and lithium-metal acid salt which contain lithium silicate (Li ₄ SiO ₄ ) as an active material of a substantial absorbent, simultaneously prevent agglomeration of active material and facilitate regeneration . As a result, the dry absorbent is excellent in regeneration of carbon dioxide even when it is driven at a high temperature for a long time, maintains a high absorption capacity, and can be regenerated at a low temperature.

For example, the high-temperature dry absorbent contains 3.6 to 5 moles of lithium (Li) per mole of silicon (Si), and the metal contained in the metal oxide, that is, aluminum (Al) or zirconium (Zr) 5 to 15% by weight based on the total weight of the composition. For example, the high-temperature dry absorbent may comprise 4 moles of lithium relative to 1 mole of silicon and 10 wt% of aluminum relative to the total weight.

In FIG. 1, a mixed raw material includes a metal oxide. However, lithium silicate (Li ₄ SiO ₄ ) is first produced by reacting lithium precursor with silicon oxide, and then lithium metasilicate (Li ₂ SiO ₃ ) can be mixed to produce a dry absorbent for high temperature. At this time, the dry-type dry absorbent includes lithium silicate (Li ₄ SiO ₄ ) and lithium metasilicate (Li ₂ SiO ₃ ). In addition, an additive for improving the ability to absorb carbon dioxide can be further added to lithium silicate (Li ₄ SiO ₄ ) and lithium metasilicate (Li ₂ SiO ₃ ).

Hereinafter, the present invention will be described in more detail by way of specific examples and comparative examples and their characteristic evaluations. However, the following examples are intended to illustrate the present invention only, and the scope of the present invention is not limited thereto.

Preparation of Samples 1-1 to 1-3 (Change in content of aluminum oxide)

Lithium carbonate and silicon oxide were mixed at a molar ratio of 2: 1 and 10 wt% of γ-aluminum oxide was added based on the weight of the total absorbent, followed by mixing for 30 minutes using a mortar. The mixed sample was placed in an aluminum oxide crucible and dried in an air atmosphere at 150 ° C for 4 hours in a heating furnace, and further heated to 700 ° C for 5 hours to obtain Sample 1 according to Example 1-1 of the present invention -1 (LS2Al (G) 10).

Further, by using substantially the same process as Sample 1-1 except that the content of? -Al 2 O 3 was added in an amount of 20% by weight and 30% by weight based on the weight of the total absorbent, 1-2 (LS2Al (G) 20) and Sample 1-3 (LS2Al (G) 30) according to Example 1-3, respectively.

Preparation of Comparative Sample 1

Comparative Example 1 (LS2) according to Comparative Example 1 was prepared by mixing, drying and calcining lithium carbonate and silicon oxide in a molar ratio of 2: 1.

Evaluation of Samples 1-1 to 1-3 and Comparative Sample 1: Carbon dioxide absorption capacity

For each of Samples 1-1 to 1-3 and Comparative Sample 1, 1 g of sorbent was placed in a 3/4 in diameter fixed bed reactor to measure the carbon dioxide absorbing capacity, and 10 vol.% Of carbon dioxide, 10 vol.% Of H ₂ O, N ₂ 80 vol% mixed gas was passed through the reactor. The absorption reaction of the absorbent was carried out under the nitrogen atmosphere while maintaining the temperature condition of 550 ° C and the regeneration temperature of 700 ° C. The absorption capacity is represented by the amount (mg) of carbon dioxide absorbed per g of absorbent, and the results are shown in Table 1 and Fig. 2A.

division 1 cycle
(mg CO ₂ / g sorbent) 2 cycles
(mg CO ₂ / g sorbent) 3 cycles
(mg CO ₂ / g sorbent) Sample 1-1
(LS2Al (G) 10) 202.2 210.6 208.1 Sample 1-2
(LS2Al (G) 20) 110.9 127.5 126.1 Samples 1-3
(LS2Al (G) 30) 48.9 44.3 49.3 Comparative Sample 1
(LS2) 227.1 166.6 103.5

Referring to FIG. 2A and Table 1, it can be seen from the results of Comparative Example 1 that the absorption capacity decreases as the experiment is repeated, that is, as the number of cycles increases, whereas in the case of Samples 1-1 to 1-3, . In FIG. 2A, the left bar indicates the result of one cycle in each sample, and the number of cycles increases toward the right. Particularly, in the case of Comparative Sample 1 in three cycles, the absorption ability was remarkably lowered to 1/2 or more, whereas in samples 1-1 to 1-3 according to the present invention, the absorption ability was hardly changed and Sample 1-1 (LS2Al (G) 10), the absorption capacity is almost constant even though the absorption capacity is high and the repeated experiment is proceeded, and it can be seen that it is an absorbent containing the most appropriate amount of γ-aluminum oxide.

XRD analysis of Samples 1-1 to 1-3 and Comparative Sample 1

For Samples 1-1 to 1-3 and Comparative Sample 1, XRD analysis before carbon dioxide absorption was performed and the results are shown in FIG. 2b.

(LS2Al (G) 10) and Sample 1-2 (LS2Al (G) 10) are shown in FIG. 2 G) 20 and Sample 1-3 (LS2Al (G) 30).

Referring to FIG. 2B, it can be seen that lithium aluminate (LiAlO ₂ ) is produced in each of (b), (c) and (d), unlike (a). Lithium molybdate (Li ₂ SiO ₃ ) is retained after regeneration because the molar ratio of lithium carbonate which can react with silicon oxide is changed while lithium aluminate (LiAlO ₂ ) is produced by the reaction of lithium carbonate and γ-aluminum oxide. As a result, it can be seen that the coagulation phenomenon occurring at the high temperature regeneration is alleviated and the regeneration at a lower temperature than the conventional absorbent is possible.

Evaluation of Samples 1-1 to 1-3 and Comparative Sample 1: Regeneration

For each of Samples 1-1 to 1-3 and Comparative Sample 1, TPD (Temperature Programmed Desorption) analysis was performed while absorbing carbon dioxide in the presence of water at 550 ° C and then increasing the temperature from 550 ° C to 800 ° C by 1 ° C per minute . The results are shown in Fig. 2C.

Referring to FIG. 2C, in the case of Sample 1-1 (LS2Al (G) 10), Sample 1-2 (LS2Al (G) 20) and Sample 1-3 (LS2Al It can be seen that most of the carbon dioxide is discharged at a temperature near the melting point. On the other hand, in the case of Comparative Sample 1 (LS2), it can be seen that carbon dioxide is discharged at a temperature in the vicinity of 690 캜 to 700 캜. That is, it can be seen that, in the case of using the dry absorbent for high temperature according to the present invention, the sample can be regenerated even at a lower temperature than the comparative sample 1.

Preparation of Samples 1-4 to 1-6 (Change in molar ratio of lithium carbonate to silicon oxide)

Lithium silicate was prepared by firing at 700 DEG C at a molar ratio of lithium carbonate to silicon oxide of 1.5: 1, lithium aluminate prepared by reacting lithium carbonate and gamma-aluminum oxide was added in an amount of 10 wt% based on the weight of the total absorbent And mixed with lithium silicate and a mortar for 30 minutes. The mixed sample was placed in an aluminum oxide crucible and dried at 150 ° C for 4 hours in an air atmosphere in an air atmosphere. The sample was further heated to 700 ° C and fired for 5 hours to obtain Sample 1-4 (LS1.5Al (G) 10) .

Also, samples 1-5 (LS1.5Al (G) 20) and 1- (2-methyl-2-pyrrolidone) were prepared through substantially the same process as that of Sample 1-4 except that the lithium aluminate content was 20 wt% 6 (LS1.5Al (G) 30).

Evaluation of Samples 1-4 to 1-6: Carbon dioxide absorption capacity

Carbon dioxide absorption capacity evaluation was also performed on Samples 1-4 to 1-6 through substantially the same method as the carbon dioxide absorption capacity evaluation experiments of Samples 1-1 to 1-3. The results are shown in Table 2 below.

division 1 cycle
(mg CO ₂ / g sorbent) 2 cycles
(mg CO ₂ / g sorbent) 3 cycles
(mg CO ₂ / g sorbent) Samples 1-4
(LS1.5Al (G) 10) 190.5 188.3 189.7 Samples 1-5
(LS1.5Al (G) 20) 169.9 170.1 168.4 Samples 1-6
(LS1.5Al (G) 30) 157.7 156.3 157.1 Comparative Sample 1
(LS2) 227.1 166.6 103.5

Referring to Table 2, it can be seen that the carbon dioxide absorbing ability tends to decrease toward Samples 1-4, 1-5 and 1-6.

However, as a result of the regeneration test, all of the samples 1-4 to 1-6 were found to be capable of retaining the absorption ability due to lithium aluminate, and it was confirmed that lithium aluminate had a great influence on regeneration.

Preparation of Samples 1-7 and 1-8 (Variation of Aluminum Oxide Type)

Sample 1-7 (LS2Al (D) 10) was prepared through substantially the same process as that of Sample 1-1 except that? -aluminum oxide was used.

Further, Sample 1-8 (LS2Al (A) 10) was prepared through substantially the same steps as those of Sample 1-1 except that? -Aluminum oxide was used.

Evaluation of Samples 1-7 and 1-8: Carbon dioxide absorption capacity

Carbon dioxide absorption capacity evaluation of Samples 1-7 and 1-8 was also carried out by substantially the same method as that of Samples 1-1 to 1-3. The results are shown in Table 3 below.

division 1 cycle
(mg CO ₂ / g sorbent) 2 cycles
(mg CO ₂ / g sorbent) 3 cycles
(mg CO ₂ / g sorbent) Sample 1-7
(LS2Al (D) 10) 211.4 163.3 150.8 Samples 1-8
(LS2Al (A) 20) 223.0 141.7 126.0 Sample 1-1
(LS2Al (G) 10) 202.2 210.6 208.1

Referring to Table 3, it can be seen that when the metal oxide is selected as aluminum oxide, the absorption capacity of one cycle is similar regardless of the kind thereof.

However, in the case of sample 1-7 (LS2Al (D) 10) using δ-aluminum oxide, which is more stable than γ-aluminum oxide, the absorption capacity decreased as the experiment was repeated, and α- In the case of Sample 1-8 ((LS2Al (A) 10) using aluminum oxide, the absorption capacity is more decreased as the experiment is repeated. The more stable the structure of aluminum oxide is, the less the structure of lithium aluminate It was confirmed that regeneration was deteriorated as it was generated.

Preparation of Samples 2-1 to 2-3 (Change in content of zirconium oxide)

Lithium carbonate and silicon oxide were mixed at a molar ratio of 2: 1 and 10 wt% of zirconium oxide was added based on the weight of the total absorbent, followed by mixing for 30 minutes using a mortar. The mixed sample was placed in an aluminum oxide crucible and dried in an air atmosphere at 150 ° C for 4 hours in an air atmosphere. The mixture was further heated to 700 ° C and fired for 5 hours to obtain a sample 2 according to Example 2-1 of the present invention -1 (LS2Z10P).

Further, the same procedure as in Sample 2-1 was repeated except that the content of zirconium oxide was 20% by weight and 30% by weight based on the weight of the total absorbent, 2 (LS2Al (G) 20) and Example 2-3 (LS2Al (G) 30), respectively.

Evaluation of Samples 2-1 to 2-3 and Comparative Sample 1: Carbon dioxide absorption capacity

For each of the samples 2-1 to 2-3 and the comparative sample 1, the carbon dioxide absorbing ability was measured in substantially the same manner as in the experiment for evaluating the carbon dioxide absorbing ability for the sample 1-1. The results are shown in Table 4 and Fig. 3A.

division 1 cycle
(mg CO ₂ / g sorbent) 2 cycles
(mg CO ₂ / g sorbent) 3 cycles
(mg CO ₂ / g sorbent) Sample 2-1
(LS2Z10P) 202.2 210.6 208.1 Sample 2-2
(LS2Z20P) 110.9 127.5 126.1 Sample 2-3
(LS2Z30P) 48.9 44.3 49.3 Comparative Sample 1
(LS2) 227.1 166.6 103.5

3A and Table 4, in the case of the sample 2-1 to 2-3, the change of the absorption capacity was small, whereas in the case of the comparative sample 1 (LS2) which is a hygroscopic agent produced only from lithium carbonate and silica, However, it can be seen that as the experiment progresses, it remarkably decreases.

XRD analysis of sample 2-1

Sample 2-1 was subjected to XRD analysis in each of the states before, after, and after the carbon dioxide absorption, and the results are shown in FIG. 3B.

In FIG. 3B, (a) is an XRD analysis graph before absorption, (b) is an XRD analysis graph after absorption, and (c) is an XRD analysis graph after regeneration. ₃ , ( ₃ ) represents Li ₄ SiO ₄ , (represents) Li ₂ SiO ₃ , Represents Li ₂ CO ₃ , Indicates SiO ₂ , and Z indicates ZrO ₂ .

Referring to FIG. 3B, it can be seen that the sample 2-1 exhibits complete regeneration after being converted into the original structure before and after the carbon dioxide absorption. In particular, in the case of Sample 2-1, lithium carbonate and zirconium oxide react with each other to produce lithium zirconate (Li ₂ ZrO ₃ ) by the production using zirconium oxide, whereby a molar ratio And lithium metasilicate (Li ₂ SiO ₃ ) is formed. Lithium metasilicate (Li ₂ SiO ₃ ) and lithium zirconate (Li ₂ ZrO ₃ ) are inactive materials but exist between lithium silicate (Li ₄ SiO ₄ ), which is an active material, It plays a role.

Evaluation of Sample 2-1: Regeneration

Sample 2-1 was subjected to TPD (Temperature Programmed Desorption) analysis while absorbing carbon dioxide in the presence of 550 ° C water and then increasing the temperature from 550 ° C to 800 ° C by 1 ° C per minute. The results are shown in Fig. 3C.

Referring to FIG. 3C, it can be seen that in the case of sample 2-1 (LS2Z10P), most of the carbon dioxide is discharged at a temperature in the vicinity of 610 ° C to 630 ° C. On the other hand, in the case of Comparative Sample 1 (LS2), it can be seen that carbon dioxide is discharged at a temperature in the vicinity of 690 캜 to 700 캜. That is, it can be seen that, in the case of using the dry absorbent for high temperature according to the present invention, the sample can be regenerated even at a lower temperature than the comparative sample 1.

Confirm the structure of Sample 2-1

A scanning electron microscope (SEM) photograph was taken for each of Comparative Sample 1 and Sample 2-1. The state after 7 cycles was photographed by SEM photograph. The results are shown in Fig. (B) is a photograph of Comparative Sample 1 after 7 cycles, (c) is a photograph of Sample 2-1, (d) is a photograph of Comparative Sample 1 after 7 cycles, -1.

Referring to FIG. 3D, it can be seen that, in the case of Comparative Sample 1, grain growth due to the coagulation phenomenon appears after the continuous experiment. On the other hand, in the case of the sample 2-1, after the continuous experiment, it is found that the particle size is substantially the same as before the experiment and exhibits a constant particle size without agglomeration phenomenon.

Preparation of Comparative Samples 2 and 3

Comparative Sample 2 was prepared in substantially the same manner as in Sample 1-1 except that cerium oxide was used instead of aluminum oxide.

Further, Comparative Sample 3 was prepared in substantially the same manner as in the method for producing Sample 1-1, except that magnesium oxide was used instead of aluminum oxide.

Evaluation of Samples 1-1, 2-1 and Comparative Samples 2 and 3: Carbon dioxide absorption capacity

For each of Sample 2-1 and Comparative Samples 2 and 3, the carbon dioxide absorbing ability was measured in substantially the same manner as in the carbon dioxide absorbing capacity evaluation experiment for Sample 1-1. The results are shown in Table 5.

division 1 cycle
(mg CO ₂ / g sorbent) 2 cycles
(mg CO ₂ / g sorbent) 3 cycles
(mg CO ₂ / g sorbent) Sample 1-1
(LS2Al (G) 10) 202.2 210.6 208.1 Sample 2-1
(LS2Z10P) 138.4 175.5 171.3 Comparative Sample 2
(LS2Ce10P) 90.9 59.7 58.7 Comparative Sample 3
(LS2Mg10P) 132.2 159.9 97.6

Referring to Table 5, it can be seen that, in the case of Samples 1-1 and 2-1, the carbon dioxide absorbing ability is not lowered even when the continuous experiment is performed. On the other hand, in the case of Comparative Samples 2 and 3 using cerium or magnesium, it can be confirmed that the carbon dioxide absorbing ability is remarkably lowered through continuous experiments.

Preparation of Samples 3-1 and 3-2 (addition of carbonate)

Sample 3-1 (LS2AG5K5) was prepared through substantially the same process as the production process of Sample 1-1, except that potassium carbonate was further contained in an amount of 5% by weight based on the total weight of the mixed raw materials.

Also, Sample 3-2 (LS2Z5K5) was prepared through substantially the same process as the production process of Sample 2-1, except that potassium carbonate was further contained in an amount of 5% by weight based on the total weight of the mixed raw materials.

Evaluation of Samples 3-1 and 3-2: Carbon dioxide absorption capacity

Samples 3-1 and 3-2 were evaluated in substantially the same manner as in the carbon dioxide absorption capacity evaluation experiment for Sample 1-1. The results are shown in FIG. 4A.

Also, the change of the carbon dioxide absorption capacity with time was measured. The results are shown in FIG. 4B.

Referring to FIG. 4A, it can be seen that Sample 3-1 (LS2AG5K5) and Sample 3-2 (LS2Z5K5) are only continuous tests as compared with Comparative Sample 1 (LS2), and substantially no decrease in carbon dioxide absorbing ability. It can also be seen that the sample 3-1 (LS2AG5K5) and the sample 3-2 (LS2Z5K5) exhibit higher values than those of the sample 1-1 (LS2AG10) and the sample 2-1 (LS2Z10).

Referring to FIG. 4B, it can be seen that the carbon dioxide absorption rate of Sample 3-1 (LS2AG5K5) and Sample 3-2 (LS2Z5K5) is faster than that of Comparative Sample 1 (LS2). It can also be seen that the carbon dioxide absorption rates of Sample 3-1 (LS2AG5K5) and Sample 3-2 (LS2Z5K5) are better than Sample 1-1 (LS2AG10) and Sample 2-1 (LS2Z10). That is, when the mixed raw material further containing the alkali metal carbonate is used, the carbon dioxide absorbing ability is further improved.

XRD analysis of Samples 3-1 and 3-2

XRD analysis was performed on samples 1-1 to 1-3 and Comparative Sample 1 before, after, and after the carbon dioxide absorption, and the results are shown in FIG. 4C.

(A) is a graph of Comparative Sample 1 (LS2), (b) and (c) are graphs of Sample 1-1 (LS2AG10) and Sample 2-1 (LS2Z10), (e) are graphs of Sample 3-1 (LS2AG5K5) and Sample 3-2 (LS2Z5K5), respectively.

In addition, in FIG. 4c, ■ denotes an Li ₄ SiO _4, ● represents the Li ₂ SiO _3, Represents Li ₂ CO ₃ , ? Represents SiO ₂ ,? Represents ZrO ₂ ,? Represents LiAlO ₂ ,? Represents Li ₂ ZrO ₃ , and? Represents LiKCO ₃ .

Referring to FIG. 4C, Sample 3-1 (LS2AG5K5) and Sample 3-2 (LS2Z5K5) show complete regeneration as shown by (d) and (e) . On the other hand, it can be seen that, in the case of Comparative Sample 1 (LS2) as in (a), it was not reproduced as before the absorption. On the other hand, the sample 1-1 (LS2AG10) and the sample 2-1 (LS2Z10) show complete regeneration as shown in (b) and (d) .

Evaluation of Samples 3-1 and 3-2: Regeneration

For each of Samples 3-1 and 3-2, TPD (Temperature Programmed Desorption) analysis was performed while absorbing carbon dioxide in the presence of 550 ° C water and then increasing the temperature by 1 ° C per minute from 550 ° C to 800 ° C. The result is shown in Fig. 4D.

Referring to FIG. 4D, it can be seen that most of the carbon dioxide is discharged at a temperature in the vicinity of 610 ° C. to 630 ° C. in each of the sample 3-1 (LS2AG5K5) and the sample 3-2 (LS2Z5K5). On the other hand, in the case of Comparative Sample 1 (LS2), it can be seen that carbon dioxide is discharged at a temperature in the vicinity of 690 캜 to 700 캜. That is, it can be seen that, in the case of using the dry absorbent for high temperature according to the present invention, the sample can be regenerated even at a lower temperature than the comparative sample 1.

Preparation of Samples 4-1 to 4-3

A sample mixed with lithium carbonate and silicon oxide in a molar ratio of 2: 1 was placed in an aluminum oxide crucible and dried in an air atmosphere at 150 ° C. for 4 hours in an air atmosphere. The resultant was further heated to 700 ° C. and calcined for 5 hours, Silicate.

Then, 10% by weight of lithium metasilicate was added to the prepared lithium silicate based on the weight of the total absorbent, and the resulting mixture was mixed for 30 minutes using a mortar to prepare Sample 4-1 (LS2ME10).

Also, Sample 4-2 (LS2ME20) and Sample 4-2 (LS2ME20) were obtained through substantially the same process as Sample 4-1, except that the content of lithium metasilicate was added at 20 wt% and 30 wt% 4-3 (LS2ME30).

Evaluation of Samples 4-1 to 4-3: Carbon dioxide absorption capacity

For each of Samples 4-1 to 4-3, the carbon dioxide absorbing ability was measured in substantially the same manner as in the carbon dioxide absorbing capacity evaluation experiment for Sample 1-1. The results are shown in Table 6.

division 1 cycle
(mg CO ₂ / g sorbent) 2 cycles
(mg CO ₂ / g sorbent) 3 cycles
(mg CO ₂ / g sorbent) Sample 4-1
(LS2ME10) 179.2 180.1 181.0 Sample 4-2
(LS2ME20) 164.2 161.5 162.7 Sample 4-3
(LS2ME30) 130.7 128.6 127.9 Comparative Sample 1
(LS2) 227.1 166.6 103.5

Referring to Table 6, in the case of the comparative sample 1 made of only lithium silicate, the carbon dioxide absorbing ability is lowered by the continuous experiment, while in the case of the samples 4-1 to 4-3, the carbon dioxide absorbing ability is not deteriorated . That is, it can be seen that the reduction of the carbon dioxide absorbing ability is prevented by the lithium metasilicate.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the present invention as defined by the following claims. It can be understood that it is possible.

Claims (16)

Mixing a lithium precursor, silicon oxide, and a metal oxide to form a mixed raw material;
Drying the mixed raw material to obtain a lithium silicate solid; And
And calcining the obtained lithium silicate solid to form a dry absorbent for high temperature.
A process for preparing a dry siloxane based high temperature dry sorbent for carbon dioxide removal.
The method according to claim 1,
The metal oxide
Characterized in that it comprises aluminum oxide or zirconium oxide.
A process for preparing a dry siloxane based high temperature dry sorbent for carbon dioxide removal.
The method according to claim 1,
Characterized in that the metal oxide is gamma-aluminum oxide.
A process for preparing a dry siloxane based high temperature dry sorbent for carbon dioxide removal.
The method according to claim 1,
The metal oxide
Is 1 to 30% by weight based on the total weight of the mixed raw materials.
A process for preparing a dry siloxane based high temperature dry sorbent for carbon dioxide removal.
The method according to claim 1,
Characterized in that the mixing raw material further comprises an alkali metal carbonate.
A process for preparing a dry siloxane based high temperature dry sorbent for carbon dioxide removal.
6. The method of claim 5,
The alkali metal carbonate
Is 1 to 10% by weight based on the total weight of the mixed raw materials.
A process for preparing a dry siloxane based high temperature dry sorbent for carbon dioxide removal.
6. The method of claim 5,
The alkali metal carbonate
Is 1 to 5% by weight based on the total weight of the mixed raw materials.
A process for preparing a dry siloxane based high temperature dry sorbent for carbon dioxide removal.
The method according to claim 1,
The lithium precursor
Lithium carbonate, lithium carbonate, lithium oxalate, lithium oxalate, lithium acetate and lithium nitrate.
A process for preparing a dry siloxane based high temperature dry sorbent for carbon dioxide removal.
The method according to claim 1,
Wherein the lithium precursor is lithium carbonate.
A process for preparing a dry siloxane based high temperature dry sorbent for carbon dioxide removal.
The method according to claim 1,
The high-temperature dry absorbent
Characterized in that it comprises lithium silicate (Li ₄ SiO ₄ ) and lithium metasilicate (Li ₂ SiO ₃ )
A process for preparing a dry siloxane based high temperature dry sorbent for carbon dioxide removal.
Reacting a lithium precursor and silicon oxide to obtain lithium silicate (Li ₄ SiO ₄ ); And
And mixing lithium silicate with lithium metasilicate (Li ₂ SiO ₃ ).
A process for preparing a dry siloxane based high temperature dry sorbent for carbon dioxide removal.
12. The method of claim 11,
Characterized in that the additive is further mixed in the step of mixing the lithium metasilicate,
A process for preparing a dry siloxane based high temperature dry sorbent for carbon dioxide removal.
Lithium silicate (Li ₄ SiO _4); And
A dry absorbent for high temperature, comprising lithium metasilicate (Li ₂ SiO ₃ ).
14. The method of claim 13,
Characterized in that it further comprises a lithium-metalate salt comprising any one of lithium aluminate and lithium zirconate.
Dry absorbent for high temperature.
14. The method of claim 13,
Characterized in that it further comprises a lithium-carbonate represented by LiMCO ₃ , wherein M represents potassium (K) or sodium (Na).
Dry absorbent for high temperature.
14. The method of claim 13,
3.6 to 5 moles of lithium (Li) per 1 mole of silicon (Si)
(Al) or zirconium (Zr) in an amount of 5 to 15% by weight based on the total weight.
Dry absorbent for high temperature.

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