JP2009291770A - Carbon dioxide gas absorbing material, and absorbing/releasing method and absorbing/releasing device for carbon dioxide gas - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a carbon oxide gas absorbing material capable of performing absorption/releasing of a carbon dioxide gas (CO<SB>2</SB>) in an atmosphere and having a sufficient carbon dioxide gas absorbing property. <P>SOLUTION: The carbon dioxide gas absorbing material is a carbon dioxide gas absorbing material containing Li<SB>2</SB>CuO<SB>2</SB>. Li<SB>2</SB>CuO<SB>2</SB>is preferably obtained by cooling a mixture obtained by mixing at least one selected from Li<SB>2</SB>O, Li<SB>2</SB>CuO<SB>2</SB>and LiOH with copper oxide at a temperature descending speed of 3.5°C/sec or higher after heating it at a temperature area of 655-965°C. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

The present invention relates to a carbon dioxide absorber that absorbs carbon dioxide (CO ₂ ), and a carbon dioxide absorption / release method and absorption / release apparatus using the same.

In recent years, in order to prevent global warming, it is required to reduce greenhouse gas emissions, and to reduce carbon dioxide (CO ₂ ), which accounts for the majority of greenhouse gases. Technological development aimed at reducing carbon dioxide is classified into improving energy conversion efficiency, exploring and developing new energy, and collecting and sequestering carbon dioxide.

  Of these, research and development on carbon dioxide recovery and sequestration has been actively conducted in recent years, and research and development of carbon dioxide absorbers that can efficiently absorb carbon dioxide have been actively conducted. .

Since the source of carbon dioxide is a power plant or a plant with a melting furnace, many carbon dioxide absorbers that can withstand high temperatures have been researched and developed. Under such circumstances, it has been found that lithium composite oxide and carbon dioxide react to produce oxide and lithium carbonate. Lithium zirconate (Li ₂ ZrO ₃ ), which is a lithium composite oxide, reacts with carbon dioxide gas at the low temperature side around 700 ° C. to become zirconium oxide (ZrO ₂ ) and lithium carbonate (Li ₂ CO ₃ ), It is known that on the high temperature side, carbon dioxide is released to return to lithium zirconate (see, for example, Non-Patent Document 1).
Li ₂ ZrO ₃ + CO ₂ → ZrO ₂ + Li ₂ CO ₃
The maximum amount of carbon dioxide absorbed by this lithium zirconate is 28.74% by mass.

Further, this document describes that lithium silicate (Li ₄ SiO ₄ ) exhibits the same reaction behavior as the following reaction formula in addition to lithium zirconate.
Li ₄ SiO ₄ + CO ₂ → Li ₂ SiO ₃ + Li ₂ CO ₃
From this reaction formula, the maximum absorption amount of carbon dioxide in lithium silicate (Li ₄ SiO ₄ ) is 36.72% by mass.

Further, as a lithium composite oxide in which the carbon dioxide absorption amount of the carbon dioxide absorbent is improved, a carbon dioxide absorbent using lithium titanate (Li ₄ TiO ₄ ) has been proposed (for example, Non-Patent Documents 2 to 2). 3). As shown in the following reaction formula, this lithium titanate absorbs carbon dioxide gas at the low temperature side around about 860 ° C. and releases carbon dioxide gas at the high temperature side.
Li ₄ TiO ₄ + 1.5CO ₂ → LiTiO _2.5 + 1.5Li ₂ CO ₃
From this reaction formula, the maximum absorption amount of carbon dioxide of lithium titanate (Li ₄ TiO ₄ ) is 43.1% by mass. This amount of absorption is the largest among the lithium composite oxide carbon dioxide absorbents.

On the other hand, as a compound itself which is a lithium composite oxide, a compound represented by Li ₂ CuO ₂ is also known.
Ceramics 37 (2002) No. 11 BL Dubey and AR West, Nature Physical Science, vol.235, February 21 (1972) RP Gunawardane, et al., J. Solid State Chem 112, 70-72 (1994)

However, as described above, lithium titanate (Li ₄ TiO ₄ ) has a large carbon dioxide absorption, but in order to synthesize Li ₄ TiO ₄ , a hydrogen gas atmosphere or an inert gas containing hydrogen gas is used as the atmosphere. There must be. In addition, in carbon dioxide gas or in the atmosphere, it is difficult to completely release carbon dioxide from a carbon dioxide absorbent that has absorbed carbon dioxide. In order to completely release carbon dioxide from the carbon dioxide absorbent that has absorbed carbon dioxide, it is necessary to use a hydrogen gas atmosphere or an inert gas containing hydrogen gas as the atmosphere.

Further, a widely known compound represented by Li ₂ CuO ₂ contains a lot of unnecessary phases (including impurities) as a non-equilibrium alloy structure, and it is difficult to obtain a single phase or a single crystal. If a large amount of such unnecessary phases (impurities) and crystal grain boundaries are present, the carbon dioxide absorption capacity is hardly obtained. That is, the Li ₂ CuO ₂ single-phase or single-crystal compound has not been obtained so far, and the actual condition is that the absorption ability of carbon dioxide gas by Li ₂ CuO ₂ has not been expected.

The present invention has been made in view of the above, and is capable of absorbing and releasing carbon dioxide (CO ₂ ) in a carbon dioxide-containing atmosphere such as the atmosphere, and has a good carbon dioxide absorbability. Another object of the present invention is to provide a carbon dioxide absorption / release method and an absorption / release device that has high carbon dioxide (CO ₂ ) absorption and can absorb and release carbon dioxide in an atmosphere containing carbon dioxide such as the atmosphere. The goal is to achieve this.

Specific means for achieving the above object are as follows. That is, the present invention
<1> A carbon dioxide absorbent containing Li ₂ CuO ₂ .
According to the carbon dioxide absorbing material described in the above <1>, the amount of carbon dioxide absorbed and the absorption efficiency are high, and carbon dioxide can be absorbed and released in an atmosphere containing carbon dioxide such as the atmosphere. Further, since the absorption reaction is an exothermic reaction, carbon dioxide gas can be absorbed under heat-saving energy after heat is applied in the initial stage of absorption.

<2> the _Li 2 CuO _{2 was} heated Li 2 O, _Li 2 CO _3, and at least one a mixture obtained by mixing a copper oxide selected from LiOH in a temperature range of from 655 to 965 ° C. Thereafter, the carbon dioxide absorbent material according to <1>, which is obtained by cooling at a temperature lowering rate of 3.5 ° C./second or more.

According to the carbon dioxide absorbent described in the above <2>, the carbon dioxide absorbent is made of Li ₂ CuO with less impurities by reacting at 655 to 965 ° C. and quenching at a temperature lowering rate of 3.5 ° C./second or more. It consists of _two . Thus, the amount of carbon dioxide absorbed can be increased.

<3> The carbon dioxide absorbent according to <2>, wherein the temperature region is 680 to 700 ° C., and the temperature lowering rate is 4.0 ° C./second or more.
<4> The carbon dioxide gas absorbent according to any one of <1> to <3>, wherein the Li ₂ CuO ₂ is a single phase or a single crystal.

According to the carbon dioxide absorbent according to the above <3>, the reaction temperature and the cooling temperature are further set to 680 to 700 ° C. and 4.0 ° C./second or more, so that the single phase or single crystal Li ₂ CuO is obtained. ₂ is obtained. A single phase or a single crystal can ensure a larger gas absorption than conventional Li ₄ SiO ₄ , and Li ₂ CuO ₂ needs to be operated in a hydrogen gas atmosphere like conventional Li ₄ TiO _4. There is no.

<5> Li ₂ CuO ₂ is synthesized by heating a mixture obtained by mixing copper oxide with at least one selected from Li ₂ O, Li ₂ CO ₃ , and LiOH in a temperature range of 655 to 965 ° C. And a step of cooling the Li ₂ CuO ₂ at a temperature lowering rate of 3.5 ° C./second or more after heating.

  <6> The method for producing a carbon dioxide absorbent according to <5>, wherein the temperature region is 680 to 700 ° C, and the temperature lowering rate is 4.0 ° C / second or more.

According to the method for producing a carbon dioxide absorbent as described in <5> above, the reaction is carried out at 655 to 965 ° C. and quenched at a temperature lowering rate of 3.5 ° C./second or more, so that impurities are reduced and carbon dioxide is absorbed. Li ₂ CuO ₂ (carbon dioxide absorbent) having a high amount and absorption efficiency is obtained.
In addition, according to the method for producing a carbon dioxide absorbent as described in <6>, single phase or single crystal Li ₂ CuO ₂ is obtained.

  <7> A carbon dioxide absorption step of absorbing carbon dioxide in a carbon dioxide containing gas using the carbon dioxide absorbent according to any one of <1> to <4>, and carbon dioxide is absorbed. A carbon dioxide gas releasing step of heating the carbon dioxide gas absorbing material and releasing the carbon dioxide gas from the carbon dioxide gas absorbing material.

According to the carbon dioxide absorption / release method according to <7> and the carbon dioxide absorption / release device according to <10> below, carbon dioxide containing Li ₂ CuO ₂ having high carbon dioxide absorption and high absorption efficiency By using an absorbent material, carbon dioxide can be absorbed and released in an atmosphere containing carbon dioxide such as air. Further, since the absorption reaction is an exothermic reaction, carbon dioxide gas can be absorbed under heat-saving energy after heat is applied in the initial stage of absorption. Further, since Li ₂ CuO ₂ is a single phase or a single crystal, a larger gas absorption amount than that of conventional Li ₄ SiO ₄ is ensured, and operation in a hydrogen gas atmosphere like conventional Li ₄ TiO ₄ is ensured. It is possible to absorb and release carbon dioxide gas in the atmosphere etc.

<8> The carbon dioxide absorption step, wherein the carbon dioxide absorption material is heated in a temperature range of 210 to 875 ° C. in a carbon dioxide-containing atmosphere. Is the method.
According to the carbon dioxide absorption and desorption method described in <8> above, heating can be selected from a wide temperature range, and carbon dioxide absorption accompanied by an exothermic reaction can be performed by heating at a relatively low temperature of, for example, 500 ° C. or less. , Energy consumption can be reduced.

  <9> The carbon dioxide gas releasing step is the carbon dioxide gas absorbing / releasing method according to <7>, wherein the carbon dioxide gas absorbing material is heated in a temperature range of 650 to 900 ° C. in the atmosphere. .

  According to the method for absorbing and releasing carbon dioxide described in the above <9>, the carbon dioxide gas is easily released and the release efficiency is good.

  <10> The carbon dioxide gas absorbing means according to any one of <1> to <4>, wherein the carbon dioxide gas absorbing means absorbs carbon dioxide in the carbon dioxide-containing gas, and the carbon dioxide gas is absorbed. And a carbon dioxide gas releasing means for heating the carbon dioxide gas absorbing material and releasing the carbon dioxide gas from the carbon dioxide gas absorbing material.

  <11> The carbon dioxide absorbing means further includes at least two gas flow passages in which the carbon dioxide containing gas is circulated, and the carbon dioxide absorbing material is disposed in the flow path so as to be in contact with the carbon dioxide containing gas, and The carbon dioxide-containing gas is supplied to the at least two gas flow passages, and the supply of the carbon dioxide-containing gas is stopped and the carbon dioxide gas is stopped. The carbon dioxide gas according to <10>, further comprising switching means for selectively switching to the at least one gas flow passage through which the absorbent material is heated and the carbon dioxide gas released by heating flows. Absorption and emission device.

  According to the carbon dioxide absorption / release apparatus of <11>, two or more gas flow passages are arranged as regions where carbon dioxide can be absorbed and released, and the carbon dioxide absorbed by each of the carbon dioxide absorbents. By switching between absorption and release for each gas distribution pipe according to the gas amount, etc., the gas storage function of the apparatus and the gas supply function to the outside are enhanced, so carbon dioxide is absorbed and / or released. In this case, carbon dioxide can be absorbed / fixed (stored) or externally supplied (discharged) in a large amount or continuously.

According to the present invention, it is possible to provide a carbon dioxide absorbent that can absorb and release carbon dioxide (CO ₂ ) in a carbon dioxide-containing atmosphere such as the atmosphere and has good carbon dioxide absorbability.
According to the present invention, it is possible to provide a carbon dioxide absorption / release method and an absorption / release apparatus that have high carbon dioxide (CO ₂ ) absorption and can absorb and release carbon dioxide in an atmosphere containing carbon dioxide such as the atmosphere. it can.

  Hereinafter, the carbon dioxide absorbing material and the method for producing the same, and the carbon dioxide absorbing and releasing method and the absorbing and releasing apparatus using the same will be described in detail.

<Carbon dioxide absorber and method for producing the same>
The carbon dioxide gas absorbent of the present invention is composed of a compound represented by Li ₂ CuO ₂ (hereinafter also referred to as “lithium cuprate”). Li ₂ CuO ₂ can be synthesized in the air, has an excellent carbon dioxide absorption capability, and can absorb and release carbon dioxide in an atmosphere containing carbon dioxide such as the air. is there.

The absorption and release of carbon dioxide will be specifically described below.
As shown in the following reaction formula (1), the lithium cuprate reacts with carbon dioxide on the low temperature side at about 900 ° C. to become copper oxide (CuO) and lithium carbonate (Li ₂ CO ₃ ). Q indicates the amount of heat generated. From this reaction formula (1), the theoretical value of the maximum absorption amount of carbon dioxide (CO ₂ ) of the lithium cuprate is 40.22% by mass. Lithium cuprates are superior in carbon dioxide absorption capacity compared to conventional lithium silicates.
Li ₂ CuO ₂ + CO ₂ → CuO + Li ₂ CO ₃ + Q (1)
Further, in the carbon dioxide gas, the lithium cuprate that has absorbed the carbon dioxide gas releases the carbon dioxide gas on the high temperature side around 900 ° C. and returns to the lithium cuprate. In the atmosphere, carbon dioxide gas is released in a temperature region of 650 ° C. or higher with 650 ° C. as a boundary, and the lithium cuprate is returned.

Li ₂ CuO ₂ used as a carbon dioxide absorbing material is a phase state in which the volume ratio of the Li ₂ CuO ₂ phase in the structure constituting the carbon dioxide absorbing material is 90% by volume or more in terms of increasing the amount of CO ₂ absorption. Is preferred. Further, Li ₂ CuO ₂ preferably has a single phase or a substantially single phase, or a single crystal or a substantially single crystal, from the viewpoint of securing the maximum CO ₂ absorption amount close to the above theoretical value. . Absorption close to the theoretical value (40.22% by mass) due to the fact that the Li ₂ CuO ₂ phase occupying the structure constituting the carbon dioxide absorbent is a single phase or a substantially single phase, or a single crystal or a substantially single crystal. A quantity is obtained.

The single phase refers to a phase state in which the volume ratio of the Li ₂ CuO ₂ phase occupying the structure constituting the carbon dioxide absorbent is 99% by volume or more. The single crystal refers to a state in which the volume ratio of the Li ₂ CuO ₂ phase in the structure constituting the carbon dioxide absorbing material is 99% by volume or more and is composed of one crystal grain. And the case where it consists of several coarse crystal grains is a substantially single crystal.

The synthesis of Li ₂ CuO ₂ is, for example, a step of obtaining a mixture by mixing at least one selected from Li ₂ O, Li ₂ CO ₃ , and LiOH with copper oxide as shown in the following reaction formula (2) ( Hereinafter, it may be referred to as “mixture preparation step”), a step of heating the obtained mixture in a temperature range of 655 to 965 ° C. (hereinafter also referred to as “heating step”), and a temperature lowering rate after heating. It can be suitably performed by a method provided with a step of cooling at 3.5 ° C./second or more (hereinafter sometimes referred to as “cooling step”).
Li ₂ CO ₃ (s) + CuO (s) → Li ₂ CuO ₂ (s) + CO ₂ (g) (2)

In the mixture preparation step, at least one selected from Li ₂ O, Li ₂ CO ₃ , and LiOH and copper oxide (CuO) are mixed to obtain a mixture. The mixture can be obtained, for example, by mixing to obtain a powdered mixed powder.

Among Li ₂ O, Li ₂ CO ₃ , and LiOH, Li ₂ CO ₃ is preferable because it can be synthesized in the atmosphere.

When the powder of Li ₂ O, Li ₂ CO ₃ , or LiOH is mixed or powdered after mixing, the average particle diameter is preferably in the range of 0.1 to 10 μm, and in the range of 0.3 to 1.0 μm. Is more preferable. When the average particle size is 10 μm or less, it is advantageous in that it reacts more efficiently. Incidentally, the average particle diameter exceeds 10 [mu] _m, tends to cause a decrease in the amount of Li 2 CuO _2.

Moreover, when making powder form after mixing or mixing copper oxide (CuO) powder, the average particle diameter of CuO has the preferable range of 0.1-10 micrometers, and the range of 0.3-1.0 micrometer is more preferable. When the average particle size is 10 μm or less, it is advantageous in that it reacts more efficiently. In addition, average particle diameter exceeds 10 [mu] _m, tends to cause a decrease in the amount of Li 2 CuO _2.

  In addition, said average particle diameter is measured using an electron microscope (made by JEOL Co., Ltd.).

As a mixing ratio (x / y; molar ratio) of at least one of Li ₂ O, Li ₂ CO ₃ , and LiOH (x) and CuO (y), Li ₂ CuO ₂ is produced in terms of the amount of production. in _{2 O, Li 2 CO 3 1} : 1~2: 1, LiOH in 2: 1 to 4: 1 are preferred, the more preferred _{Li 2 O, Li 2 CO 3} 1: 1~1.5: 1, In LiOH, it is 2: 1 to 3: 1.

In the heating step, the mixture obtained in the mixture preparation step is heated in a temperature range of 655 to 965 ° C. Li ₂ CuO ₂ is obtained by heating the mixture. If the temperature range is less than 655 ° C., the temperature is too low and Li ₂ CuO ₂ is not generated, or there are many unnecessary phases (impurities), and a desired CO ₂ absorption capacity cannot be obtained. Absorption decreases. For the heating, a conventionally known method can be used.

  The atmosphere during heating need not be a hydrogen atmosphere or an inert atmosphere, and can be performed, for example, in carbon dioxide gas or a carbon dioxide-containing gas such as air.

The heating temperature is preferably in the range of 680 to 700 ° C. from the viewpoint of obtaining a CO ₂ absorption amount closer to the theoretical value, in other words, a single phase or a single crystal.
The heating time varies depending on the heating temperature, such as the amount of the mixture and the mixing ratio, but is preferably 1 to 10 hours.
In particular, the aspect of heating at a temperature of 680 to 700 ° C. for 2 to 6 hours is preferable in terms of obtaining a single phase or a single crystal.

  Further, the rate of temperature increase during heating is not particularly limited, but from the viewpoint of preventing melting of the mixture, a range of 1 to 10 ° C / min is preferable, and further 1 to 3 ° C / min. A range is preferred.

In the cooling step, after heating in the heating step, Li ₂ CuO ₂ obtained by heating is cooled at a temperature decrease rate of 3.5 ° C./second or more. After completion of the heating, the Li ₂ CuO ₂ phase consisting of a substantially single phase to a single phase or a substantially single crystal to a single crystal is cooled by lowering the temperature at a relatively fast rate of 3.5 ° C./second or more. Is obtained.

The temperature decreasing rate is preferably in the range of 4.0 ° C./second or more from the viewpoint of obtaining a CO ₂ absorption amount closer to the theoretical value, in other words, a single phase or a single crystal. Particularly preferably, when the temperature region is 680 to 700 ° C., the temperature decreasing rate is 4.0 ° C./second or more.

  In the present invention, after heating in the heating step, there may be a time zone in which the temperature is lowered at 3.5 ° C./second (preferably 4.0 ° C./second) or more. From the viewpoint of generating the temperature, it is preferable to lower the temperature to 25 ° C. (normal temperature) at a temperature lowering rate of 3.5 ° C./second (preferably 4.0 ° C./second) after the heating.

The heating step and the cooling step in the present invention can be performed using, for example, a heating furnace 20 shown in FIG. FIG. 1 is a schematic diagram for explaining an example of a mode in which Li ₂ CuO ₂ is obtained by heating and quenching in a heating furnace.

  An electric furnace can be used as the heating furnace. The heating furnace 20 shown in FIG. 1 is an electric furnace, and can be rapidly cooled by heating the sample 21 introduced into the reaction tube 22 from the outside of the reaction tube 22 and moving the sample 21 after the heating. It is configured. Heating and rapid cooling in such a heating furnace can be performed by using, for example, an Elema electric furnace manufactured by Tokai Koetsu Kogyo Co., Ltd.

In the heating furnace shown in FIG. 1, a mixture (for example, mixed powder) in which at least one selected from Li ₂ O, Li ₂ CO ₃ , and LiOH and copper oxide are mixed is introduced as a sample 21, and Li ₂ CuO is heated. A reaction tube 22 for synthesizing ₂ is provided. The sample 21 in the reaction tube can be moved in the direction of the arrow manually or by a moving mechanism (not shown).
For example, after preparing the mixed powder, this mixed powder is placed in the center of the reaction tube 22 (the center of the electric furnace) and heated at a high temperature of 700 ° C., for example. Li ₂ CuO ₂ is obtained from the mixture by heating. Preferred heating conditions such as heating temperature and time are as described above. Next, the sample 21 in the center of the electric furnace is rapidly cooled (temperature drop rate ≧ 3.5 ° C./second) by moving it outside the electric furnace (in the direction of the arrow in FIG. 1) at 50 cm / second. In this operation, the rapid cooling rate φ [° C./second] can be selected by the distance [cm] by which the sample 21 at the center of the furnace is moved from the center to the tube opening direction. For example, in FIG. 1, φ = 5.4 ° C./second when moved 50 cm from the center, and φ = 3.7 ° C./second when moved 25 cm. The rapid cooling rate φ [° C./second] can be controlled by selecting the distance [cm] for moving the sample 21 heated to a high temperature from the center of the electric furnace as desired or automatically. is there.
The start of quenching may be different depending on the starting material, and may be started from the synthesis temperature at the completion of the synthesis of Li ₂ CuO ₂ or may be started from a temperature lower than the synthesis temperature.

  The reaction tube 22 is composed of a heat-resistant tube having a length of 100 cm and an inner diameter of 25 mm, and has heat resistance capable of withstanding heating in a temperature range of at least 655 to 965 ° C. The tube is not particularly limited as long as it is heat resistant and has a tube structure. For example, a heat resistant glass tube, a metal tube, or the like can be used. The length and inner diameter of the tube can be selected according to various conditions such as the amount of sample to be introduced, the relationship between the moving distance of the sample and the cooling rate.

The Li ₂ CuO ₂ obtained as described above may be pulverized again and then heat-treated in the same manner as described above to obtain Li ₂ CuO ₂ powder.

Li ₂ CuO ₂ obtained as a powder can obtain a desired molded body by pressure molding. For example, you may shape | mold into the porous body which has a porous structure. In the case of molding a porous body from powder, it is necessary to suppress pressure loss at the time of molding and to give a certain degree of strength. Therefore, the porosity of the porous structure is preferably about 30 to 70%. Moreover, what is necessary is just to select arbitrarily the form as a carbon dioxide gas absorber according to a use etc., For example, molded objects, such as a powder, a pellet, and a spherical body (for example, about several millimeters in diameter) are mentioned.

Carbon dioxide gas absorbent of the present invention, CO ₂ absorption, CO ₂ absorption and release properties, can be applied to various fields by utilizing various properties such as handling properties at ambient moderate. Specific examples include application to the uses shown in the following 1) to 4).

1) It is effective for absorbing carbon dioxide generated from blast furnaces at power plants and steelworks.
2) Since the product when hydrogen is burned is water (H ₂ O), hydrogen (H ₂ ) is used as a cleaner fuel than methane (CH ₄ ), propane (CH ₃ CH ₂ CH ₃ ), etc. in recent years. However, the generation of hydrogen itself is widely performed by steam reforming of methane as shown in the following reaction formulas (a) and (b).
CH ₄ + H ₂ O → 2H ₂ + CO (a)
CO + H ₂ O → H ₂ + CO ₂ (b)
Placing the carbon dioxide gas absorbent of the present invention in a region where these reactions occur, Reaction Scheme (b) carbon dioxide produced by the reaction of (CO ₂₎ and is absorbed by the carbon dioxide gas absorbent CO ₂ from gas Is reduced, and the reaction of the reaction formula (b) proceeds more actively, which is effective in speeding up the production of H ₂ .

3) It is effective for removing only carbon dioxide from a mixed gas containing carbon dioxide as an impurity and increasing the purity of the mixed gas.
4) Carbon dioxide is usually transported in a heavy (heavy) metal cylinder, but if carbon dioxide is absorbed in the carbon dioxide absorbent of the present invention (Li ₂ CO ₃ ), a large amount of carbon dioxide is Since it is absorbed, it is effective in reducing the weight and safety of the means for transporting carbon dioxide. Then, after transportation it can be easily recovered carbon dioxide from the Li ₂ CO ₃ by heating.

<Method and apparatus for absorbing and releasing carbon dioxide>
The carbon dioxide absorption / release method of the present invention includes a carbon dioxide absorption step of absorbing carbon dioxide in a carbon dioxide-containing gas using the carbon dioxide absorbent of the present invention described above, and carbon dioxide in which carbon dioxide has been absorbed. A carbon dioxide gas releasing step for heating the absorbent material and releasing carbon dioxide gas from the carbon dioxide gas absorbent material is provided.

In the carbon dioxide absorption / release method of the present invention, as described above, it is configured using the carbon dioxide absorbent of the present invention containing Li ₂ CuO ₂ , which is higher than conventional lithium zirconate and lithium silicate. When carbon dioxide gas absorption capability is obtained and heat is applied, the reverse reaction of the reaction formula (1) proceeds in an atmosphere containing carbon dioxide gas such as the atmosphere, leading to decomposition of Li ₂ CuO _{2 and} the like. without it can be stably taken out CO _2. At this time, returning to Li ₂ CuO ₂ can be used repeatedly.

The carbon dioxide absorption step absorbs carbon dioxide in the carbon dioxide-containing gas using the carbon dioxide absorbent of the present invention described above. The absorption reaction of Li ₂ CuO ₂ constituting the carbon dioxide absorbent of the present invention (that is, the reaction in the right direction of the reaction formula (1)) is an exothermic reaction, and the calorific value upon gas absorption is shown in Table 1 below. Thus, it is larger than conventional lithium silicate (Li ₄ SiO ₄ ) (about 2.4 times), so after heating to promote gas absorption at the beginning of absorption, the temperature rises by itself due to heat generated during the absorption reaction. This makes it possible to store gas with less heat and energy. At this time, the heating of the carbon dioxide absorbing material is preferably performed in a temperature range of 210 to 875 ° C., more preferably 600 to 850 ° C. in a carbon dioxide containing atmosphere in that carbon dioxide gas is reacted efficiently. is there.
For example, as shown in FIG. _12, Li 2 CuO ₂ is high absorption efficiency can be obtained near 600 ° C. to 850 ° C..

In Table 1, the calorific value of Li ₄ SiO ₄ is a measured value when the temperature is raised from normal temperature to 700 ° C. at 5 ° C./min in a 100% CO ₂ atmosphere. Li ₂ CuO ₂ is a literature value calculated with reference to Solid State Ionic 46 (1991) 325-329 North-Holland and Thermochemical Data of Pure Substances Vol. II La-Zr Ihasan Barin because of its large self-heating. .

In the carbon dioxide gas releasing step, the carbon dioxide gas absorbing material in which the carbon dioxide gas is absorbed is heated to release the carbon dioxide gas from the carbon dioxide gas absorbing material. Li ₂ CuO ₂ is different from a titanic acid type that has a large gas absorption amount but requires heating in a hydrogen atmosphere.

  The heating temperature in the carbon dioxide gas releasing step is preferably 650 to 900 ° C. in terms of carbon dioxide gas releasing efficiency in the atmosphere. A heating temperature of 900 ° C. or less is particularly advantageous in that the quality of the carbon dioxide absorbent is maintained.

Using a carbon dioxide gas absorbent containing li ₂ CuO _2, and stored by absorbing carbon dioxide gas, to release carbon dioxide upon heating, heating a carbon dioxide absorbent and carbon dioxide gas absorbent of the invention described above This can be done by an apparatus equipped with heating means. Preferably, the carbon dioxide gas absorbing means of the present invention described above, the carbon dioxide absorbing means for absorbing carbon dioxide in the carbon dioxide containing gas, and the carbon dioxide absorbent having absorbed the carbon dioxide gas are heated to produce carbon dioxide. A carbon dioxide absorption / release device (a carbon dioxide absorption / release device of the present invention) provided with carbon dioxide release means for releasing carbon dioxide from the absorbent is used.

Since the carbon dioxide absorption / release apparatus of the present invention has a configuration using the carbon dioxide absorbent of the present invention containing Li ₂ CuO ₂ as described above, it has a higher carbon dioxide compared to conventional lithium zirconate and lithium silicate. When gas absorption ability is obtained and heat is applied, the reverse reaction of the reaction formula (1) proceeds in an atmosphere containing carbon dioxide gas such as the atmosphere without causing decomposition of Li ₂ CuO _{2 or} the like. CO ₂ can be taken out stably. At this time, returning to Li ₂ CuO ₂ can be used repeatedly.

  One embodiment of the carbon dioxide absorption / release apparatus of the present invention will be described with reference to FIGS. FIG. 2 is an example of a power plant.

As shown in FIG. 2, the power plant according to the present embodiment has a blower 10 to which the discharged carbon dioxide-containing gas is supplied, and a carbon dioxide storage and separation in which Li ₂ CuO ₂ (carbon dioxide absorber) is filled. 12A and 12B.

The discharged carbon dioxide-containing gas is introduced into the blower 10 as it is. The carbon dioxide containing gas introduced into the blower 10 can be directly introduced into the carbon dioxide storage separator 12A or 12B as shown in FIG. In the carbon dioxide gas storage separator 12A or 12B, the Li ₂ CuO of the present invention is circulated through the heat medium flow pipe as shown in FIG. 3 according to the temperature of the introduced carbon dioxide-containing gas. ₂ to increase the absorption efficiency of the carbon dioxide-absorbing material.

In the carbon dioxide storage separator 12A or 12B, when carbon dioxide containing gas is introduced, Li ₂ CuO ₂ absorbs carbon dioxide (CO ₂ ) in the mixed gas, and when Li ₂ CuO ₂ is heated The absorbed carbon dioxide gas can be released and separated.

As shown in FIG. 3, each of the carbon dioxide gas storage separators 12A and 12B has Li ₂ CuO ₂ 15 filled in the vessel and a heat medium flow arranged so as to be embedded in the Li ₂ CuO ₂ 15. A pipe (carbon dioxide gas releasing means) 16 is provided, and Li ₂ CuO ₂ 15 can be heated by circulating a heat medium in the heat medium flow pipe 16. In this carbon dioxide storage / separator, when carbon dioxide containing gas is supplied, carbon dioxide is absorbed, supply of mixed gas is stopped, and when heated through a heating medium, carbon dioxide gas is discharged from Li ₂ CuO ₂ 15. Is discharged, and carbon dioxide can be discharged out of the carbon dioxide storage separator.

The carbon dioxide storage separator may be filled with Li ₂ CuO ₂ 15 as shown in FIG. 3 or may be filled with Li ₂ CuO ₂ 15 in a part of the vessel. Further, a plurality of types of carbon dioxide absorbents may be mixed in the same vessel.

Li ₂ CuO ₂ 15 is formed by pressing a powdered Li ₂ CuO ₂ material into a porous shape, and carbon dioxide containing gas is introduced from one end of a flow pipe connected to a carbon dioxide storage separator. Then, the carbon dioxide-containing gas passes through the porous layer of Li ₂ CuO ₂ toward the other end, and the carbon dioxide in the gas is absorbed.

In order to obtain a porous body from a powdered carbon dioxide absorbent (here, Li ₂ CuO ₂ ), it is necessary to suppress pressure loss and to have a certain degree of strength, so the porosity is 20 to 70%. Is preferable, and 30 to 70% is more preferable. The form of the carbon dioxide absorbing material should be arbitrarily selected according to the application for which the carbon dioxide absorbing material is used, and examples thereof include powder, pellets, balls of several mm, and the like.
At this time, the introduction speed of the mixed gas is preferably in the range of 100 to 300 ml / min.

Inside the carbon dioxide gas storage separator 12A (12B), a heating medium circulation pipe 16 is provided for circulating a heating medium (liquid such as heated oil or water) in order to raise the temperature of Li ₂ CuO _2. The heat medium is circulated continuously or as necessary, and carbon dioxide gas can be released from Li ₂ CuO ₂ .

Further, the heating means for heating the carbon dioxide absorbent (here, Li ₂ CuO ₂ ) is not limited to heat exchange by circulating the heat medium as described above, but the carbon dioxide absorbent is directly heated by using a heater or the like. You may do it.

The heating of the carbon dioxide absorbing material (here Li ₂ CuO ₂ ) is only required to obtain a temperature at which the carbon dioxide absorbed by the carbon dioxide absorbing material can be released, and is preferably in the temperature range of 650 to 900 ° C. in the atmosphere. It is.

In the present embodiment, two carbon dioxide gas storage separators (gas flow passages) 12A and 12B are provided as carbon dioxide gas absorbing means. When these two carbon dioxide gas storage separators absorb carbon dioxide, Then, it is configured to be able to switch between each other so that carbon dioxide gas is released. Specifically, as shown in FIG. 2, valves V1 and V2 are attached as switching means to pipings on the mixed gas supply side of the carbon dioxide storage separators 12A and 12B, and the valves V1 and V2 are driven to open and close. Thus, the carbon dioxide storage separators 12A and 12B can be switched between the carbon dioxide absorption side and the carbon dioxide release side. For example, when the valve V1 is opened, the valve V2 is closed, carbon dioxide is supplied to the carbon dioxide storage separator 12A, and carbon dioxide is absorbed and stored by the carbon dioxide storage separator 12A. In the gas storage separator 12B, Li ₂ CuO ₂ is heated to release carbon dioxide. Conversely, when the valve V2 is opened, the valve V1 is closed, carbon dioxide is supplied to the carbon dioxide storage separator 12B, and carbon dioxide is absorbed and stored in the carbon dioxide storage separator 12B. In the carbon dioxide storage separator 12A, Li ₂ CuO ₂ is heated to release carbon dioxide.

Thus, for example, when the supply port on the carbon dioxide containing gas supply side of the carbon dioxide storage separator 12B is closed and the carbon dioxide containing gas is supplied to the carbon dioxide storage separator 12A, the supplied carbon dioxide is supplied. Carbon dioxide in the contained gas is absorbed and fixed in the carbon dioxide storage separator 12A. At this time, when the absorption of carbon dioxide in the carbon dioxide storage separator 12A reaches a saturated state, the gas supply port (not shown) on the carbon dioxide containing gas supply side to the carbon dioxide storage separator 12A is closed to store the carbon dioxide. The gas supply port (not shown) on the carbon dioxide containing gas supply side of the separator 12B is opened, and the carbon dioxide in the carbon dioxide containing gas supplied to the carbon dioxide storage separator 12B is the same as in the case of the carbon dioxide storage separator 12A. It is similarly absorbed and immobilized. On the other hand, in the carbon dioxide gas storage / separator 12A in which the absorption of carbon dioxide gas reaches a saturated state, the carbon dioxide gas absorbed and fixed in the carbon dioxide absorbent is released, so that the heat medium flow pipe 16 is heated at a temperature of 650 to 900 ° C. Through the medium, Li ₂ CuO ₂ is heated. After the release of the carbon dioxide gas, the valve is set so that the carbon dioxide-containing gas is supplied to the carbon dioxide gas storage separator 12A again while checking the amount of carbon dioxide absorbed by the carbon dioxide gas storage separator 12B as necessary. V1 is switched, and the carbon dioxide storage separator 12B releases carbon dioxide absorbed and fixed in the carbon dioxide absorbent while determining whether or not the absorption of carbon dioxide has reached saturation as necessary. The Li ₂ CuO ₂ is heated by circulating a heat medium having a temperature of 650 to 900 ° C. through the heat medium flow pipe 16 disposed in the carbon dioxide storage separator 12B. By repeating this operation, carbon dioxide can be absorbed and discharged (released) continuously. In addition, a large amount of carbon dioxide gas can be stored or discharged according to external demands.

  Determination of whether or not the absorption of carbon dioxide has reached a saturated state is, for example, a method of detecting the amount of carbon dioxide in the gas discharged from the carbon dioxide storage separators 12A and 12B after absorption of carbon dioxide with a carbon dioxide detection sensor It can be carried out by a method of measuring by weight change.

When releasing the carbon dioxide absorbed by the carbon dioxide absorbent, when the inside of the carbon dioxide storage / separator 12A in which the carbon dioxide is absorbed is held in a temperature range of 650 to 900 ° C., the carbon dioxide absorbent (here, Li ₂ CuO ₂ ) can resume gas absorption in the carbon dioxide storage / separator 12A as described above after the carbon dioxide is released.

Carbon dioxide gas released from Li ₂ CuO ₂ in the carbon dioxide gas storage separator 12A and the carbon dioxide gas storage separator 12B is sent to the outside for recovery as shown by a broken line arrow in FIG. 2, or requires carbon dioxide gas It is used in the equipment.

In the above, as an example of the carbon dioxide absorption / release method and the absorption / release apparatus according to the present invention, the description has been made mainly on the power plant using Li ₂ CuO ₂ as the carbon dioxide absorbent. Any device may be used as long as it uses a process for separating and releasing the gas from the carbon dioxide absorbent, and the present invention is not limited to this. In addition, the case where the heating of Li ₂ CuO ₂ is performed by circulating the heat medium through the heat medium flow pipe has been mainly described, but the present invention is not limited to this, and 650 Li ₂ CuO ₂ is directly heated by a heater, etc. The same applies when another heating means capable of heating to ˜900 ° C. is selected.

  In the above description, the case where two carbon dioxide gas storage / separators are provided has been mainly described, but three or more carbon dioxide gas storage / separators can be provided.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to the following examples unless it exceeds the gist thereof.

Lithium carbonate (Li ₂ CO ₃ ) powder having an average particle diameter of 1.0 μm and copper oxide (CuO) powder having an average particle diameter of 0.8 μm are 1: 1 in a molar ratio (Li ₂ CO ₃ : CuO). And dry-mixed for 1 hour in an agate mortar. The obtained mixed powder was placed on a gold foil, heated in the air from room temperature (25 ° C.) to 700 ° C. at a heating rate of 5 ° C./min with a box-type electric furnace, and reached each temperature shown in Table 2 below. Then, heat treatment was performed at that temperature for 20 hours. After the heat treatment was completed, powdered Li ₂ CuO ₂ (sample Nos. 1 to 15) was obtained by cooling at a temperature lowering rate [° C./second] shown in Table 2 below.
Each of the obtained Li ₂ CuO ₂ powders was filled into a cylinder having a diameter of 12 mm and subjected to pressure molding to produce a molded body having a porosity of 40%.

-1. Li ₂ CuO ₂ structure
The crystal structure of each of the obtained powdery Li ₂ CuO ₂ was analyzed by X-ray diffraction. For the analysis, XRD RINT2000 type (manufactured by Rigaku Denki Co., Ltd.) was used. The analysis results are shown in FIGS.
4 to 6 are X-ray diffractograms of Li ₂ CuO ₂ with the temperature drop rates fixed at 3.7 ° C./second, 5.4 ° C./second, and 1.0 ° C./second, respectively. 7 to 9 are X-ray diffraction diagrams of Li ₂ CuO ₂ with the heating temperature fixed at around 655 ° C. (650 ° C., 660 ° C., 700 ° C.), and FIGS. It is an X-ray diffraction pattern of Li ₂ CuO ₂ with the temperature fixed at around 965 ° C. (960 ° C., 970 ° C.) for comparison.

When the mixed powder is heated to synthesize Li ₂ CuO ₂ within a heating temperature range of 655 to 965 ° C., a phase with less impurities is obtained when the temperature decreasing rate is 3.7 ° C./second as shown in FIG. When the temperature drop rate is increased to 4.0 ° C./second or more, impurities are reduced as shown in FIG. 5, and further, the heating temperature is set to 680 to 700 ° C. and 4.0 ° C./second or more. The phase Li ₂ CuO ₂ was obtained. On the other hand, when the cooling rate is slow, less impurities be kept in the same manner as in the above heating temperature as shown in FIG. 6, more could not be obtained Li ₂ CuO ₂ of single phase.

Further, looking at the phase state when the heating temperature is around 655 ° C., there are many impurities (unnecessary phases) as shown in FIG. 7 at 650 ° C., whereas impurities (unnecessary phases) at 660 ° C. as shown in FIG. Unnecessary phases) decreased and the temperature was further raised to 700 ° C., and a phase state approaching a single phase was obtained as shown in FIG. In addition, when the heating temperature was 700 ° C., single-phase Li ₂ CuO ₂ was obtained when the rate of temperature decrease was 4.0 ° C./second or more.

  Looking at the phase state when the heating temperature is around 965 ° C., there are many impurities (unnecessary phases) as shown in FIG. 11 at 970 ° C., whereas impurities (unnecessary as shown in FIG. 10 at 960 ° C.). Phase).

-2. Carbon dioxide absorption-
The obtained Li ₂ CuO ₂ (carbon dioxide absorbent) is placed in a carbon dioxide atmosphere having a concentration of 100% by volume, and the temperature is increased from room temperature (25 ° C.) to 1000 ° C. at a temperature increase rate of 5 ° C./min. The mass change of Li ₂ CuO ₂ was measured using a thermogravimetric analyzer (MTS9600, manufactured by Vacuum Riko Co., Ltd.), and the maximum change amount (maximum absorption amount) of carbon dioxide gas was obtained. This maximum change amount was divided by the mass of the sample used for measurement, and the maximum mass change rate [mass%] of carbon dioxide gas per 1 g of the sample was calculated. The results are shown in Table 2 below and FIGS.

In the present invention, CO ₂ is absorbed at about 200 to 900 ° C., and as shown in Table 2, the CO ₂ absorption amount is large in a temperature range of 660 ° C. or higher (preferably 960 ° C. or lower). The value (40.2% by mass) was achieved. That is, in the present invention, single phase or single crystal Li ₂ CuO ₂ was obtained. It was found that CO ₂ was released at 900 ° C. or higher as shown in FIGS. In addition, since the absorption reaction is an exothermic reaction, after heating in the initial stage of absorption at a relatively low temperature, it is possible to store carbon dioxide gas that suppresses the consumption of heat energy by self-heating due to heat generated by absorption. Further, as shown in FIG. 15, Li ₂ CuO ₂ has a wide temperature range capable of maintaining a large amount of CO ₂ absorption compared to, for example, conventional lithium silicate (Li ₄ SiO ₄ : maximum absorption amount 36.7% by mass). This is also advantageous in terms of handling.
On the other hand, in the comparative example, the CO ₂ absorption amount was significantly lower than the theoretical value, and the carbon dioxide absorption capacity was inferior. Further, _Li 2 CuO ₂ of the comparative example a large amount of impurities, it was not possible to obtain a single phase.

-3. Carbon dioxide release
In the above sample No. The molded body using 7 Li ₂ CuO ₂ was completely absorbed with CO ₂ in a carbon dioxide gas atmosphere having a concentration of 100% by volume until the absorption amount reached 40.2% by mass, and then this Li ₂ CuO ₂ was removed into the atmosphere. The temperature was increased from room temperature (25 ° C.) to 1000 ° C. at a rate of temperature increase of 5 ° C./min using a thermogravimetric analyzer (MTS9600, manufactured by Vacuum Riko Co., Ltd.). ] Was measured with a thermogravimetric analyzer. The measurement results are shown in FIG.

As shown in FIG. 16, _Li 2 CuO ₂ after the absorption of CO ₂ was released with CO ₂ at 650 ° C. or higher in the atmosphere. Since the mass reduction rate has reached the theoretical mass reduction rate, it is considered that CO ₂ was released and Li ₂ CuO ₂ was regenerated.

In the present embodiment has been described mainly a case of synthesizing the _Li 2 CuO ₂ with _Li 2 CO _3, it is the same case of synthesizing the _Li 2 CuO ₂ by using Li 2 O, the LiOH.

It is a schematic perspective view which shows an example of the heating furnace used for implementation of the heating process and cooling process in the manufacturing method of the carbon dioxide absorber of this invention. It is a schematic block diagram which shows one Embodiment of the absorption / release apparatus of the carbon dioxide gas of this invention. It is an enlarged view which expands and shows the cross-section of the carbon dioxide storage separator which comprises the absorption-and-release apparatus of FIG. It is an X-ray diffraction pattern of Li ₂ CuO ₂ or the like synthesized at a temperature decrease rate of 3.7 ° C./second. It is a X-ray diffraction pattern of _Li 2 CuO ₂ and the like synthesized at a cooling rate of 5.4 ° C. / sec. It is an X-ray diffraction pattern of Li ₂ CuO ₂ or the like synthesized at a temperature drop rate of 1.0 ° C./second. It is an X-ray diffraction pattern of Li ₂ CuO ₂ or the like synthesized at a heating temperature of 650 ° C. It is an X-ray diffraction pattern of Li ₂ CuO ₂ or the like synthesized at a heating temperature of 660 ° C. It is an X-ray diffraction diagram of Li ₂ CuO ₂ or the like synthesized at a heating temperature of 700 ° C. It is an X-ray diffraction diagram of Li ₂ CuO ₂ or the like synthesized at a heating temperature of 960 ° C. It is an X-ray diffraction diagram of Li ₂ CuO ₂ or the like synthesized at a heating temperature of 970 ° C. Cooling rate 5.4 ° C. / sec is a graph showing the mass change ratio of the synthesized _Li 2 CuO ₂ at a heating temperature of 700 ° C.. Temperature drop rate 3.7 ° C. / sec is a graph showing the mass change ratio of the synthesized _Li 2 CuO ₂ at a heating temperature of 700 ° C.. Cooling rate 1.0 ° C. / sec is a graph showing the mass change ratio of the synthesized _Li 2 CuO ₂ at a heating temperature of 700 ° C.. Is a graph comparing the mass change ratio of Li ₂ CuO ₂ and _Li 4 SiO _4. No. of an Example. 7 is a graph showing the mass reduction rate of _Li 2 CuO ₂ molded body.

Explanation of symbols

12A, 12B · · · carbon dioxide reservoir separator 15 ··· _{Li 2} CuO 2
16 ... heat medium flow pipe 20 ... heating furnace 21 ... sample _{(Li 2 O, Li 2 CuO} 2, and a mixture of at least one copper oxide in LiOH)

Claims (11)

Carbon dioxide absorbing material containing Li ₂ CuO ₂ . The Li ₂ CuO ₂ is a mixture obtained by mixing at least one selected from Li ₂ O, Li ₂ CO ₃ , and LiOH and copper oxide in a temperature range of 655 to 965 ° C. The carbon dioxide absorbent according to claim 1, wherein the carbon dioxide absorbent is obtained by cooling at a rate of 3.5 ° C / second or more.   3. The carbon dioxide absorbent according to claim 2, wherein the temperature range is 680 to 700 ° C., and the rate of temperature decrease is 4.0 ° C./second or more. The carbon dioxide gas absorbent according to any one of claims 1 to 3, wherein the Li ₂ CuO ₂ is a single phase or a single crystal. A step of synthesizing Li ₂ CuO ₂ by heating a mixture obtained by mixing at least one selected from Li ₂ O, Li ₂ CO ₃ , and LiOH and copper oxide in a temperature range of 655 to 965 ° C .; ,
A step of cooling the Li ₂ CuO ₂ at a rate of temperature decrease of 3.5 ° C./second or more after heating;
The manufacturing method of the carbon dioxide gas absorption material which has this.   The said temperature range is 680-700 degreeC, The said temperature-fall rate is 4.0 degreeC / sec or more, The manufacturing method of the carbon dioxide absorber of Claim 5 characterized by the above-mentioned. A carbon dioxide absorption step of absorbing carbon dioxide in the carbon dioxide-containing gas using the carbon dioxide absorbent according to any one of claims 1 to 4,
A carbon dioxide releasing step of heating the carbon dioxide absorbing material in which carbon dioxide is absorbed, and releasing carbon dioxide from the carbon dioxide absorbing material;
A method for absorbing and releasing carbon dioxide gas.   The carbon dioxide absorption step according to claim 7, wherein the carbon dioxide absorption step heats the carbon dioxide absorption material in a temperature range of 210 to 875 ° C in a carbon dioxide containing atmosphere.   The method for absorbing and releasing carbon dioxide according to claim 7, wherein in the carbon dioxide releasing step, the carbon dioxide absorbing material is heated in a temperature range of 650 to 900 ° C in the atmosphere. Carbon dioxide absorbing means for absorbing carbon dioxide in a carbon dioxide-containing gas, comprising the carbon dioxide absorbent according to any one of claims 1 to 4,
Carbon dioxide gas releasing means for heating the carbon dioxide gas absorbing material in which carbon dioxide gas has been absorbed and releasing carbon dioxide gas from the carbon dioxide gas absorbing material;
Carbon dioxide absorption / release device. The carbon dioxide absorbing means further includes
At least two gas flow passages in which the carbon dioxide gas-absorbing material is disposed in the flow path so that the carbon dioxide gas-containing gas flows and contacts the carbon dioxide gas-containing gas;
The carbon dioxide-containing gas is supplied to the at least two gas flow passages, and at least one gas flow passage through which the supplied carbon dioxide-containing gas circulates, and the supply of the carbon dioxide-containing gas is stopped and the carbon dioxide gas is absorbed. Switching means for selectively switching to at least one gas flow passage in which the material is heated and the carbon dioxide gas released by heating flows.
The carbon dioxide absorption / release apparatus according to claim 10, comprising:

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