JP2021069963A - Carbon dioxide decomposition apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To continuously decompose carbon dioxide by heat treatment using an alkali silicic oxide as a catalyst. SOLUTION: The carbon dioxide decomposition apparatus according to the present invention uses an alkali siliceous oxide as a catalyst and heats a catalyst holding portion which is a portion where the alkali siliceous oxide is retained to remove carbon dioxide passing through the catalyst holding portion. A device used for decomposition treatment that decomposes into carbon and oxygen, in which a catalyst holding region, which is a region in which a catalyst is held, containing at least an alkali siliceous oxide, and carbon generated on the surface of the alkali siliceous oxide are surfaced. A carbon peeling mechanism for peeling from the carbon and a catalyst holding region and a carbon peeling mechanism are housed inside. At least the catalyst holding region is heated to a predetermined temperature by a heating facility, and the generated carbon and oxygen are discharged from the discharge port. A carbon dioxide-containing gas introduction unit for introducing carbon dioxide-containing gas into the catalyst holding region in the chamber, and a dust collector for collecting carbon discharged from the discharge port are provided. [Selection diagram] Fig. 1

Description

The present invention relates to a carbon dioxide decomposition apparatus.

In recent years, carbon dioxide (CO ₂ ) in the atmosphere has been increasing steadily, and it is said that such CO ₂ in the atmosphere contributes to global warming. _{Therefore, there is a demand for a method of recovering CO 2} in the atmosphere by a simple method and decomposing it into carbon (C), and various proposals have been made so far.

For example, Patent Document 1 below, an alkali silicate compound, water in the presence of (H 2 _O) to absorb the CO _2, CO ₂ by heating an alkali silicate product that has absorbed CO ₂ at a predetermined temperature A method of decomposing and separating C has been proposed.

Japanese Unexamined Patent Publication No. 2018-131351

_{When CO 2} in the atmosphere is decomposed according to the method proposed in Patent Document 1, C generated by the decomposition is accumulated on the surface of the alkaline silicic acid oxide and gradually becomes a catalyst for the alkaline silicic acid oxide. The activity is deactivated. Therefore, in order to continue the decomposition reaction of _{CO 2 , it is necessary to temporarily stop the decomposition reaction of CO 2} and exfoliate C from the surface of the alkali silicic acid oxide, and continuous decomposition of _{CO 2 is required.} The process has not been realized yet.

Therefore, the present invention has been made in view of the above problems, and an object of the present invention is that carbon dioxide can be continuously decomposed by heat treatment using an alkali silicic oxide as a catalyst. The purpose is to provide a carbon dioxide decomposition device.

As a result of diligent studies by the present inventor in order to solve the above problems, the surface of the alkali silicic acid oxide is provided with a carbon exfoliation mechanism for exfoliating carbon generated on the surface of the alkali silicic acid oxide as a catalyst. It was found that it is possible to continue the carbon dioxide decomposition reaction while exfoliating the carbon that accumulates in the alkali.
The present invention has been completed based on such findings, and the gist thereof is as follows.

(1) A decomposition treatment in which an alkali siliceous oxide is used as a catalyst and carbon dioxide passing through the catalyst holding portion is decomposed into carbon and oxygen by heating the catalyst holding portion which is a portion where the alkali siliceous oxide is retained. The catalyst holding region, which is a region where the catalyst is held, which contains at least the alkali siliceous oxide, and the carbon dioxide generated on the surface of the alkaline siliceous oxide are peeled off from the surface. The mechanism and the catalyst holding region and the carbon exfoliation mechanism are housed therein, and at least the catalyst holding region is heated to a predetermined temperature by a heating facility, and the generated carbon and the oxygen are discharged from the discharge port. A carbon dioxide-containing gas introduction unit for introducing carbon dioxide-containing gas into the catalyst holding region in the chamber, and a dust collector for collecting the carbon discharged from the discharge port. Carbon dioxide decomposition equipment.
(2) The chamber has a tapered portion whose internal region expands in the vertical direction upward, and the catalyst holding region is provided in the tapered portion or below the tapered portion, and the carbon. As a peeling mechanism, pores are provided at the upper end in the vertical direction and the lower end in the vertical direction of the catalyst holding region, respectively, and have a pore diameter smaller than the average particle size of the alkali siliceous oxide particles. The carbon dioxide decomposition apparatus according to (1), which has a pair of porous members.
(3) The carbon dioxide decomposition apparatus according to (2), wherein a fluidized bed of the alkali silicic acid oxide is formed by the carbon dioxide-containing gas introduced in the catalyst holding region.
(4) The volume of the catalyst holding region is twice or more and 100 times or less the volume of the alkali siliceous oxide contained in the catalyst holding region, and the carbon dioxide-containing gas causes the alkali siliceous oxide particles to be vertically oriented. The carbon dioxide decomposition apparatus according to (2) or (3), which collides with the porous member located on the upper side.
(5) The taper shape of the tapered portion, according to any one of (2) to (4), wherein the alkali silicic acid particles scattered from the catalyst holding region are settled to the catalyst holding region. Carbon dioxide decomposition device.
(6) The catalyst holding region further contains at least one of amorphous fibers containing alumina and silica as main components, crystalline fibers containing alumina and silica as main components, and quartz wool (2). )-(5). The carbon dioxide decomposition apparatus according to any one of (5).
(7) The carbon dioxide decomposition apparatus according to (1), wherein the catalyst holding region further contains quartz wool that functions as the carbon peeling mechanism.
(8) In the catalyst holding region, the alkali silicic acid is retained by locating the quartz wool at the upstream and downstream ends of the alkaline silicic oxide in the gas flow direction, respectively (7). ). The carbon dioxide decomposition apparatus.
(9) The carbon dioxide decomposition according to (7) or (8), wherein the alkali silicic acid oxide is retained in the catalyst holding region in a state where the alkali silicic acid oxide particles and the quartz wool are mixed. apparatus.
(10) The catalyst holding region is held inside the chamber by a pair of porous members provided with pores having a pore diameter smaller than the average particle size of the alkali silicic acid particles (7). The carbon dioxide decomposition apparatus according to any one of (9).
(11) The catalyst holding region further contains at least one of an amorphous fiber containing alumina and silica as main components and a crystalline fiber containing alumina and silica as main components (7) to (1). The carbon dioxide decomposition apparatus according to any one of 10).
(12) The gas flow direction in the chamber is from the lower side to the upper side in the vertical direction, and a tapered portion whose internal region expands toward the upper side in the vertical direction is provided on the upstream side of the chamber. The catalyst holding region is provided at a portion corresponding to the tapered portion, and the tapered shape of the tapered portion allows the alkali siliceous oxide particles scattered from the catalyst holding region to reach the catalyst holding region. The carbon dioxide decomposition apparatus according to any one of (7) to (11), which is settled.
(13) The heating facility is a horizontal trough-type solar furnace that heats a heating target by condensing sunlight, and the catalyst is placed on a horizontally held linear condensing portion of the trough-type solar furnace. The carbon dioxide decomposition apparatus according to any one of (7) to (11), wherein a holding region is provided.
(14) The carbon dioxide decomposition apparatus according to any one of (1) to (12), wherein the heating facility is a solar furnace that heats a heating target by condensing sunlight.
(15) The method according to any one of (1) to (14), wherein the flow rate of the carbon dioxide-containing gas introduced from the carbon dioxide-containing gas introduction unit is controlled according to the heating capacity of the heating equipment. Carbon dioxide decomposition equipment.
(16) The carbon dioxide decomposition according to any one of (1) to (15), wherein a dehydrator for removing water in the carbon dioxide-containing gas is provided on the upstream side of the carbon dioxide-containing gas introduction unit. apparatus.

As described above, according to the present invention, carbon dioxide can be continuously decomposed by heat treatment using an alkaline silicic oxide as a catalyst.

It is explanatory drawing which schematically showed an example of the whole structure of the carbon dioxide decomposition apparatus which concerns on each embodiment of this invention. It is explanatory drawing which showed typically an example of the structure of the chamber part of the carbon dioxide decomposition apparatus which concerns on 1st Embodiment of this invention. It is explanatory drawing which showed typically an example of the structure of the chamber part of the carbon dioxide decomposition apparatus which concerns on this embodiment. It is explanatory drawing which showed typically an example of the structure of the catalyst holding part in the chamber part which concerns on the same embodiment. It is explanatory drawing which showed typically an example of the structure of the chamber part of the carbon dioxide decomposition apparatus which concerns on 2nd Embodiment of this invention. It is explanatory drawing which showed typically an example of the structure of the catalyst holding part in the chamber part which concerns on the same embodiment. It is explanatory drawing which showed typically an example of the structure of the catalyst holding part in the chamber part which concerns on the same embodiment. It is explanatory drawing which shows another example of the structure of the chamber part of the carbon dioxide decomposition apparatus which concerns on this embodiment schematically.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the present specification and the drawings, components having substantially the same functional configuration are designated by the same reference numerals, so that duplicate description will be omitted.

(Overall configuration of carbon dioxide decomposition device)
First, the overall configuration of the carbon dioxide decomposition apparatus according to each embodiment of the present invention will be described with reference to FIG. FIG. 1 is an explanatory diagram schematically showing an example of the overall configuration of the carbon dioxide decomposition apparatus according to each embodiment of the present invention.

The carbon dioxide decomposition apparatus according to each embodiment of the present invention uses alkaline siliceous oxide particles as a catalyst and passes through the catalyst holding portion by heating the catalyst holding portion which is a portion where the alkaline siliceous oxide particles are held. This device is used for decomposition treatment that decomposes carbon dioxide (CO ₂ ) into carbon (C) and oxygen (O _2).

<Alkaline silicic acid>
Here, the alkali silicic acid oxide used as a catalyst is not particularly limited as long as it can be used for the decomposition treatment of _{CO 2, and various alkaline silicic acid oxides can be used.}

As such an alkaline silicic acid oxide, for example, an alkaline silicic acid oxide represented by the general formula mM ₂ O · SiO ₂ (M = Li, Na, K, m = positive real number) can be mentioned. Some of these alkaline silicic oxides _{have high or low CO 2} absorption characteristics, and some have high or low CO ₂ decomposition characteristics into C. Each is different. In particular, when attention is focused on the trend in the type of alkali metal M (alkali metal), the absorption properties of CO ₂ is high Li in order of, Na, K, degradation characteristics (CO ₂ to the CO ₂ C Decomposition characteristics) are K, Na, and Li in order from the highest, contrary to the absorption characteristics. Regarding the absorption of CO ₂ , it can be understood that O is sucked at the time of _{CO 2} absorption, in descending order of the effective nuclear charge of the alkaline element. Regarding the decomposition characteristics of CO ₂ , the order of ease of decomposition of alkaline coal oxide is considered from the viewpoint of Gibbs energy.

Examples of such an alkali silicic oxide include mLi ₂ O · SiO ₂ (m = 2.4 to 4.6), mNa ₂ O · SiO ₂ (m = 0.3 to 4.0), mK ₂ O ·. SiO ₂ (m = 3.4 to 5.4) and the like can be mentioned. Regarding the coefficient m indicating the ratio of the alkali metal element M, when M = Li, m is more preferably in the range of 3.0 to 3.8, and further preferably 3.4. Further, in the case of M = Na, m is more preferably in the range of 2.0 to 3.8, and further preferably 3.6. Further, in the case of M = K, m is more preferably in the range of 4.0 to 4.8, and further preferably m = 4.4. As the various alkaline silicic oxides, those commercially available as industrial products or reagents may be used, or those synthesized using commercially available industrial products or reagents may be used. An example of a method for synthesizing an alkali silicic acid oxide will be briefly described below.

In the focused carbon dioxide decomposition reaction, to adsorb CO ₂ in an alkaline silicate compound, to decompose the CO ₂ in the C and O ₂ by heating, alkali silicate compound may have a shape such as excellent gas absorptive It is preferable to do so. Therefore, the shape of the alkali silicic oxide is preferably powdery or granular rather than lumpy, and more preferably granular with an average particle size of about 0.1 μm to 5 mm, and the average particle size is It is more preferable that the particle size is about 1 μm to 2 mm. Here, the average particle size of the alkaline silicic oxide means the particle size at an integrated value of 50% in the particle size distribution obtained by the laser diffraction / scattering method or the vibration type sieving method. If the particle size of the alkali silicic oxide is made too small, impurities may be mixed in during the pulverization process. Therefore, even if the alkali silicate is pulverized, the average particle size is preferably about 0.1 μm.

Further, in the carbon dioxide decomposition apparatus 1 according to each embodiment of the present invention, among the alkali silicic oxides using the alkali metal elements as described above, a plurality of types of alkalis having at least one of the alkali metal element M and the coefficient m different from each other Silicic acids may be used in combination with each other. By adjusting the combination method and compounding ratio of these alkaline silicic oxides, it is possible to adjust whether the adsorption reaction or the decomposition reaction is emphasized, or to adjust the catalytically active temperature range of the alkaline silicic acid oxide to a desired temperature range. It becomes possible to do. At this time, _{considering both the adsorption efficiency of CO 2} and the decomposition efficiency into C, a _{Li-based alkaline silicic acid having excellent CO 2} adsorption characteristics and a K-based alkaline silicic acid having excellent decomposition characteristics into C It is preferable to use a compound and a combination, and it is more preferable to use a combination of 3.4Li ₂ O · SiO ₂ and 4.4K ₂ O · SiO ₂ .

When a plurality of types of alkali silicic oxides are mixed and used, the mixing ratio is not particularly limited, and may be appropriately adjusted so as to obtain desired characteristics and a desired catalytically active temperature range. Good.

[Synthesis example of alkali silicic acid: mLi ₂ O · SiO _2]
The alkali siliceous oxide mLi ₂ O · SiO ₂ can be synthesized as follows, using, for example, commercially available lithium hydroxide (or hydrate of lithium hydroxide) and silica sand as starting materials.
That is, each of the commercially available lithium hydroxide (granular special grade reagent) and silica sand (SiO ₂ ) (200 to 300 mesh) has a Li ₂ O: SiO ₂ ratio of m: 1, and lithium hydroxide and silica sand are formed. When the reaction produces mLi ₂ O · SiO _{2, the} amount that becomes the desired synthetic amount is weighed, and the mixture is charged into a nickel rut pot having a size commensurate with the weighed amount. This nickel crucible is stored in the quartz crucible as it is. The quartz crucible is covered with an alumina lid, and the temperature is raised to 1050 ° C. at 10 ° C./min in an Ar atmosphere heating furnace, held for 30 minutes, and then naturally cooled to room temperature. As a result, a uniform glass-like substance that is almost colorless and transparent is generated in the nickel crucible after cooling. When the present inventor _{synthesized 3.4 Li 2} O · SiO _{2 in the} same manner as above and measured the mass loss of the obtained product, lithium hydroxide was completely dehydrated and reacted with silica sand. consistent with mass reduction when 4Li ₂ O · SiO ₂ was formed, it was confirmed that the 3.4Li ₂ O · SiO ₂ was formed. By using the above synthesis method, it is possible to synthesize _{desired mLi 2} O · SiO _2.

[Synthesis example of alkali silicic acid: mNa ₂ O · SiO _2]
The alkali siliceous oxide mNa ₂ O · SiO ₂ can be synthesized as follows, for example, using commercially available sodium hydroxide and silica sand as starting materials.
That is, each of the commercially available sodium hydroxide (granular special grade reagent) and silica sand (SiO ₂ ) (200 to 300 mesh) has a Na ₂ O: SiO ₂ ratio of m: 1, and sodium hydroxide and silica sand are formed. When mNa ₂ O and SiO ₂ are produced by the reaction, the amount of synthesis desired is weighed, and the mixture is charged into a nickel rut pot having a size commensurate with the weighing. This nickel crucible is stored in the quartz crucible as it is. The quartz crucible is covered with an alumina lid, and the temperature is raised to 1100 ° C. at 10 ° C./min in an Ar atmosphere heating furnace, held for 30 minutes, and then naturally cooled to room temperature. As a result, a uniform glass-like substance that is almost colorless and transparent is generated in the nickel crucible after cooling. When the present inventor _{synthesized 3.6 Na 2} O · SiO _{2 in the} same manner as above and measured the mass loss of the obtained product, sodium hydroxide was completely dehydrated and reacted with silica sand. consistent with mass reduction when 6Na ₂ O · SiO ₂ was formed, it was confirmed that the 3.6Na ₂ O · SiO ₂ was formed. By using the above synthesis method, it is possible to synthesize _{desired mNa 2} O · SiO _2.

[Synthesis example of alkali silicic acid: mK ₂ O · SiO _2]
The alkali siliceous oxide mK ₂ O · SiO ₂ can be synthesized as follows, for example, using commercially available potassium hydroxide and silica sand as starting materials.
That is, each of the commercially available potassium hydroxide (special grade reagent granular) and silica sand _(SiO 2) (200 to 300 _[mesh), K ₂ O: SiO 2 ratio of m: 1, and the potassium hydroxide and silica sand When mK ₂ O · SiO ₂ is produced by the reaction, the amount to be a desired synthetic amount is weighed and charged into a nickel rut pot having a size commensurate with the weighed amount. This nickel crucible is stored in the quartz crucible as it is. The quartz crucible is covered with an alumina lid, and the temperature is raised to 1050 ° C. at 10 ° C./min in an Ar atmosphere heating furnace, held for 30 minutes, and then naturally cooled to room temperature. As a result, a uniform glass-like substance that is almost colorless and transparent is generated in the nickel crucible after cooling. When the present inventor _{synthesized 4.4K 2} O · SiO _{2 in the} same manner as above and measured the mass loss of the obtained product, potassium hydroxide was completely dehydrated and reacted with silica sand. It was confirmed that _{4.4K 2} O · SiO ₂ was formed, which coincided with the mass reduction when 4K ₂ O · SiO _{2 was formed.} By using the above synthesis method, it is possible to synthesize _{desired mK 2} O · SiO _2.

<Carbon dioxide-containing gas>
The carbon dioxide-containing gas used in the carbon dioxide decomposition apparatus 1 according to each embodiment of the present invention is not particularly limited as long as it contains _{CO 2.} As such a carbon dioxide-containing gas, for example, air can be mentioned. In addition to air, carbon dioxide-containing gas is used in thermal power plants that use coal, heavy oil, natural gas, etc. as fuel, boilers in various manufacturing plants, and blast furnaces in steelmaking plants that reduce iron oxide with coke. It is possible to use various types of exhaust gas that are emitted.

The carbon dioxide decomposition apparatus 1 according to each embodiment of the present invention used for the carbon dioxide decomposition treatment as described above includes a chamber portion 10 and a carbon dioxide-containing gas introduction portion, as schematically shown in FIG. 20 and a dust collector 30 are provided. Further, it is preferable that the carbon dioxide decomposition device 1 has a dehydration device 40 in addition to the chamber unit 10, the carbon dioxide-containing gas introduction unit 20, and the dust collector 30.

<Chamber part 10>
The chamber portion 10 is a portion that provides a space that serves as a reaction field for the decomposition reaction of carbon dioxide by the alkali silicic acid oxide. Inside the chamber portion 10, the catalyst holding portion 11 which is a portion where the alkali silicic acid oxide as a catalyst is held, and the carbon peeling for peeling the carbon generated on the surface of the alkaline silicic acid oxide from the surface of the alkaline silicic acid oxide. A mechanism (not shown) is provided. Of the chamber portions 10, at least the catalyst holding portion 11 is heated to a predetermined temperature region (for example, the catalyst activation temperature region of the alkali silica oxide as a catalyst) by a predetermined heating means, and the catalyst holding portion is in a heated state. A carbon dioxide-containing gas is supplied to the 11 from the carbon dioxide-containing gas introduction unit 20, which will be described later. When the carbon dioxide-containing gas is supplied to the catalyst holding unit 11, the alkaline silicic acid oxide functions as a catalyst, and the carbon dioxide contained in the carbon dioxide-containing gas is decomposed into carbon and oxygen gas. At this time, carbon is generated on the particle surface of the alkali silicic acid oxide which is a catalyst. Further, the carbon generated on the particle surface of the alkali silicic acid oxide is exfoliated from the particle surface of the alkaline silicic acid oxide by the function of the carbon exfoliation mechanism described in detail below.

The catalyst holding portion 11 and the carbon peeling mechanism as described above are held at specific positions inside the chamber constituting the chamber portion 10 according to each embodiment of the present invention. As a result, the carbon generated on the surface of the alkali silicic acid particles is separated from the surface of the catalyst to become carbon particles, which are discharged to the outside of the chamber portion 10 along with the flow of oxygen gas.

The chamber portion 10 will be described in detail below.

<Carbon dioxide-containing gas introduction unit 20>
The carbon dioxide-containing gas introduction unit 20 is a portion that introduces the carbon dioxide-containing gas at a predetermined flow rate into the catalyst holding unit 11 provided in the chamber unit 10. The detailed configuration of the carbon dioxide-containing gas introducing unit 20 is not particularly limited, and the carbon dioxide-containing gas can be supplied to the catalyst holding unit 11 in the chamber unit 10 at a predetermined flow rate and flow velocity. If so, various known configurations can be applied. For example, a gas supply path composed of various known gas supply pipes, various known control valves, and the like can be used as the carbon dioxide-containing gas introduction unit 20.

Further, the carbon dioxide-containing gas introducing unit 20 according to each embodiment of the present invention reacts the carbon dioxide-containing gas with the alkali siliceous oxide as a catalyst in the catalyst holding unit 11 of the chamber 10 in a desired atmosphere. May be mixed with the carbon dioxide gas supplied to the catalyst holding portion 11 in the chamber 10 with a gas that does not affect the carbon dioxide decomposition reaction. As an example of such a gas, an inert gas such as Ar or a nitrogen gas for creating a non-oxidizing atmosphere as shown below can be mentioned.

Such a carbon dioxide-containing gas introduction unit 20 may be manually controlled by the user of the carbon dioxide decomposition device 1, or may be automatically controlled by a process computer or the like that comprehensively manages the operating state of the carbon dioxide decomposition device 1. It may be controlled.

<Dust collector 30>
A mixture of carbon particles and oxygen gas discharged from a discharge port provided in the chamber portion 10 is supplied to the dust collector 30, and the carbon particles and oxygen gas are separated from the mixture to recover the carbon particles. is there. The recovered carbon can then be used as a normal carbon source such as fuel. Further, the oxygen gas separated from the mixture can be released into the atmosphere as it is, or can be separately recovered and used for various purposes.

The specific structure of such a dust collector 30 is not particularly limited, and various facilities such as a bag filter dust collector, a cyclone dust collector, a wet dust collector, and the like are appropriately used depending on the capacity of the chamber portion 10 and the like. It is possible.

<Dehydrator 40>
In the carbon dioxide decomposition apparatus 1 according to each embodiment of the present invention, the carbon dioxide-containing gas introduced into the apparatus does not contain excess water in order to further promote the decomposition reaction of carbon dioxide by the alkaline silicic oxide. Is preferable. Therefore, in the carbon dioxide decomposition device 1 according to the present embodiment, it is preferable to provide the dehydration device 40 on the upstream side of the carbon dioxide-containing gas introduction unit 20 as schematically shown in FIG. By providing such a dehydrating device 40, it is possible to make the water content of the carbon dioxide-containing gas introduced into the catalyst holding portion 11 of the chamber portion 10 through the carbon dioxide-containing gas introducing portion 20 into a more preferable state. Such a dehydrator 40 is not particularly limited, and various types such as an adsorption / absorption dehumidifier, a cooling dehumidifier, a compression dehumidifier, and the like are used depending on the scale of the carbon dioxide decomposition device 1 and the like. It is possible to use gas dehumidification equipment.

As described above, the overall configuration of the carbon dioxide decomposition apparatus 1 according to each embodiment of the present invention has been described in detail with reference to FIG.

(First Embodiment)
First, the carbon dioxide decomposition apparatus according to the first embodiment of the present invention will be described. In the carbon dioxide decomposition apparatus according to the present embodiment, as an example of the carbon peeling mechanism, a pair of porous members provided with holes having a specific pore diameter are used, and the chamber portion 10 has a specific shape. Have.

<About the configuration of the chamber section 10>
Hereinafter, an example of the chamber portion 10 included in the carbon dioxide decomposition apparatus 1 according to the present embodiment will be described in more detail with reference to FIGS. 2A to 3. 2A and 2B are explanatory views schematically showing an example of the configuration of the chamber portion of the carbon dioxide decomposition apparatus according to the present embodiment, and FIG. 3 is an explanatory view of the catalyst holding portion in the chamber portion according to the present embodiment. It is explanatory drawing which showed an example of the structure schematically.

In the following, for convenience, the coordinate axes shown in FIGS. 2A and 2B will be appropriately used for explanation. As shown in FIGS. 2A and 2B, the coordinate axes are such that the vertical upward direction is the Z-axis positive direction and the plane defined by the X-axis and the Y-axis corresponds to the horizontal plane.

The chamber portion 10 according to the present embodiment includes a chamber 100 provided with a catalyst holding portion 11 and a heating facility 50 for heating at least the catalyst holding portion 11 of the chamber 100 to a desired temperature range.

Here, the heating equipment 50 is not particularly limited as long as it can at least heat the alkaline silicic oxide existing in the catalyst holding portion 11 in the chamber 100, and various heating furnaces, electric furnaces, and heating devices. Etc. can be used as appropriate. At this time, FIG. 2 shows a case where the catalyst holding portion 11 exists inside the heating facility 50, but if the alkaline silicic acid oxide existing in the catalyst holding portion 11 can be heated to a desired temperature, the catalyst holding portion 11 is held. The part 11 does not have to exist inside the heating equipment 50. Further, as the heating equipment 50 according to the present embodiment, the exhaust heat discharged from various high-temperature processes can be used as long as it is within the range of the catalyst activation temperature, and a heating device utilizing the exhaust heat can be used. It is also possible to use it.

Further, as the heating equipment 50 according to the present embodiment, it is also possible to use a heating device using renewable energy, and as a heating device using such renewable energy, a solar furnace that condenses sunlight. Can be exemplified. The heating temperature of a solar furnace often fluctuates depending on the weather conditions, but in the present invention, it can be used because the temperature range required for the carbon dioxide decomposition reaction is wide. Further, since the carbon dioxide decomposition according to the present invention is an endothermic reaction, it is possible to control the temperature of the catalyst holding unit 11 by controlling the amount of carbon dioxide that is circulated for decomposition. That is, if the heating capacity of the solar furnace used as the heating facility 50 is insufficient, the amount of carbon dioxide introduced is reduced, and conversely, if the heating capacity of the solar furnace is excessive, the amount of carbon dioxide introduced is increased to maintain the catalyst. The temperature of unit 11 may be controlled. Further, by using a solar furnace that collects sunlight as the heating facility 50, it is possible to realize a more environmentally friendly carbon dioxide decomposition device 1.

The chamber 100 used for the chamber portion 10 has a tapered portion 101 located on the upstream side in the gas flow path direction and a non-tapered portion 101 located on the downstream side of the tapered portion 101, as schematically shown in FIGS. 2A and 2B. It has a tapered portion 103. Further, a reverse tapered portion 105 may be provided further downstream of the non-tapered portion 103, as schematically shown in FIGS. 2A and 2B.

Here, the material of the chamber 100 is not particularly limited, and may be appropriately selected depending on the amount of carbon dioxide-containing gas to be treated, the strength required for the chamber 100, and the like. Further, the capacity of the chamber 100 is not particularly limited, and may be appropriately determined according to the amount of carbon dioxide-containing gas to be treated and the like.

The tapered portion 101 is provided after the carbon dioxide-containing gas supply port 107 in the chamber 100, and is a portion in which the internal region expands toward the upper side in the vertical direction (the Z-axis positive direction side in FIGS. 2A and 2B). ing. In the carbon dioxide decomposition apparatus 1 according to the present embodiment, the catalyst holding portion 11 may be provided below the tapered portion 101 (for example, directly below the tapered portion 101) as shown in FIG. 2A. As shown in 2B, it may be provided in the internal space of the tapered portion 101. At this time, at least the catalyst holding portion 11 is provided so as to be located inside the heating equipment 50. As a result, the alkaline silicic acid oxide held in the catalyst holding portion 11 is heated to the catalyst active temperature range and held at a desired temperature.

The carbon dioxide-containing gas supplied from the supply port 107 to the catalyst holding portion 11 passes through the catalyst holding portion 11 provided below the tapered portion 101 (FIG. 2A) or in the internal space of the tapered portion 101 (FIG. 2B). Then, the carbon dioxide decomposition reaction proceeds using the alkaline silicic acid oxide located in the catalyst holding portion 11 as a catalyst. As a result, carbon particles and oxygen gas are generated from carbon dioxide in the carbon dioxide-containing gas. The generated carbon particles and oxygen gas pass through the non-tapered portion 103 located on the downstream side of the tapered portion 101, or the non-tapered portion 103 and the reverse tapered portion 105, and pass through the discharge port 109 to the outside of the chamber 100. It is discharged.

FIG. 3 is a schematic view showing an enlarged portion of the catalyst holding portion 11 as shown in FIG. 2A, which is provided below the tapered portion 101. As schematically shown in FIG. 3, the catalyst holding portion 11 according to the present embodiment has a catalyst holding region 111, which is a region in which the alkali silica oxide as a catalyst is held, and a vertical upper side of the catalyst holding region 111. It is composed of a pair of perforated members 113 that function as a carbon peeling mechanism, which are located at the end portion and the end portion on the lower side in the vertical direction, respectively. Here, the porous member located on the lower side of the catalyst holding region 111 in the vertical direction (the negative side of the Z axis in FIG. 3) is referred to as the lower porous member 113A, and is referred to as the upper side of the catalyst holding region 111 in the vertical direction (Z in FIG. 3). The porous member located on the positive direction side of the axis) is referred to as an upper porous member 113B.

Here, the amount of the alkaline silicic oxide retained in the catalyst holding region 111 is not particularly limited, and the size of the chamber 100 and the amount of carbon dioxide-containing gas to be treated (for example, carbon dioxide per unit time) are not particularly limited. It may be appropriately set according to the amount of carbon-containing gas introduced) and the like. However, the alkaline silicic acid oxide is not so tightly held by the porous member 113 that it is difficult for the alkaline silicic acid oxide particles to move inside the catalyst holding region 111, but the particles ride on the gas flow. It is preferably held in a movable state.

Further, in addition to the alkaline silicic acid oxide, the catalyst holding region 111 according to the present embodiment may contain a catalyst scattering preventing material for preventing excessive scattering of the alkaline silicic acid oxide. Examples of such a catalyst shatterproof material include at least one of an amorphous fiber containing alumina and silica as main components, a crystalline fiber containing alumina and silica as main components, and quartz wool. The content of the catalyst shatterproof material is not particularly limited, and can be appropriately adjusted within a range that does not hinder the progress of the carbon dioxide decomposition reaction.

Lower perforated members 113A and upper perforated members 113B that function as carbon peeling mechanisms are provided at both ends of the catalyst holding region 111 in the vertical direction as described above, and each of the perforated members 113A and 113B is made of alkali. A pore portion (not shown) having a pore diameter smaller than the average particle size of the siliceous oxide is provided. More specifically, the upper porous member 113B is provided with pores that are smaller than the average particle size of the alkaline silicic oxide and larger than the average particle size of the carbon particles to be produced. By providing such a pore portion, the gas can permeate the entire catalyst holding portion 11 composed of the lower porous member 113A, the catalyst holding region 111, and the upper porous member 113B, and the alkali silicic acid as a catalyst. The compound is held by the lower perforated member 113A. Further, the alkaline silicic acid oxide on which the carbon particles generated by the reaction adheres to the surface rides on the flow of the supplied gas and collides with the upper porous member 113B, so that the generated carbon particles are separated from the surface of the alkaline silicic acid oxide. Then, it passes through the upper perforated member 113B and scatters in the direction of the non-tapered portion 103.

The materials of the lower perforated member 113A and the upper perforated member 113B are not particularly limited, and various materials may be used as long as they have sufficient strength even at the temperature at which the catalyst holding portion 11 is held. It can be used, and a non-metal material may be used, or a metal material may be used. Examples of such a material include various porous bodies such as a porous body of a glass plate and a porous body of various ceramics, and various mesh-like materials such as a stainless steel wire mesh.

The density of the pores provided in the lower porous member 113A and the upper porous member 113B depends on the amount and pressure of the carbon dioxide-containing gas to be introduced into the catalyst holding region 111, the residence time of the carbon dioxide-containing gas in the catalyst holding region 111, and the like. It may be set as appropriate according to the situation. Further, the size of the hole portion, the abundance density of the hole portion, and the like may be the same value for the lower porous member 113A and the upper porous member 113B, or may be different values.

With the configuration of the catalyst holding portion 11 and the porous member 113 as described above, in the carbon dioxide decomposition apparatus 1 according to the present embodiment, the carbon particles generated on the surface of the alkaline silicic acid oxide are peeled off to form the alkaline silicic acid oxide as a catalyst. It is possible to suppress the deactivation of carbon dioxide and continuously decompose carbon dioxide.

Further, the specific gravities of the alkaline silicic oxide and the produced carbon particles are significantly different. Further, since the catalyst holding portion 11 is provided below the tapered portion 101 (FIG. 2A) or in the internal space of the tapered portion 101 (FIG. 2B), the gas passing through the tapered portion 101 is vertically upward (Z-axis). The flow velocity gradually decreases toward the positive direction). Therefore, even if the alkaline silicic acid oxide is pulverized with time and passes through the pores provided in the upper porous member 113B, the alkaline silicic acid oxide is separated by specific gravity and settles toward the catalyst holding portion 11. That is, in the tapered portion 101 according to the present embodiment, the alkaline silicic acid particles scattered from the catalyst holding region 111 can be settled to the catalyst holding region 111 due to the tapered shape of the tapered portion 101.

In the present embodiment, the shape of the catalyst holding portion 11 is not particularly limited, and may be a tapered shape that gently connects to the tapered portion 101 above (for example, directly above), a simple cylindrical shape, or the like. It may have various non-tapered shapes such as.

Further, the catalyst holding region 111 may be provided so as to be a fixed bed when the carbon dioxide decomposition apparatus 1 according to the present embodiment is put into operation, but it is alkaline due to the carbon dioxide-containing gas introduced. It is preferable that the siliceous oxide is provided so as to form a fluidized layer. As a result, the reaction cross section of the alkali silicic acid oxide as a catalyst is increased, and the reaction efficiency of the carbon dioxide decomposition reaction can be further improved. Further, by forming the fluidized bed, the alkaline silicic acid oxide having carbon particles adhered to the surface will collide violently with the upper porous member 113B, and the carbon particles will be more reliably separated from the surface of the alkaline silicic acid oxide. It becomes possible.

Further, the volume of the catalyst holding region 111 is preferably 2 times or more and 100 times or less the volume of the alkaline silicic oxide contained in the catalyst holding region 111. Here, the bulk of the alkaline silicic oxide is not the bulk of the alkaline silicic oxide inside the carbon dioxide decomposition apparatus 1 in the operating state, but the carbon dioxide-containing gas is not supplied and the catalyst holding region 111 is allowed to stand still. The bulk of the alkali silicic oxide in the state of being made. When the volume of the catalyst holding region 111 satisfies the above relationship, the fluidized bed can be realized in a more preferable state in the catalyst holding region 111. The volume of the catalyst holding region 111 is more preferably 5 times or more and 20 times or less the volume of the alkaline silicic acid oxide.

In the catalyst holding unit 11 as described above, the atmosphere at the time of reaction is preferably a non-oxidizing atmosphere. By creating such an atmosphere, it is possible to more reliably prevent the produced carbon from being oxidized. Examples of such a non-oxidizing atmosphere include an atmosphere of an inert gas such as an Ar atmosphere and a nitrogen atmosphere. The purity of the non-oxidizing gas used may be the purity of a general gas cylinder (for example, 99.99%). With this degree of purity, the oxidation of the produced carbon can be virtually ignored. The flow rate of the non-oxidizing gas is not particularly specified, and may be a small amount from an economical point of view. For the purpose of preventing the pressure inside the chamber 100 from rising or being damaged due to heating, the flow rate may be set so that the non-oxidizing gas does not flow back from the exhaust port. Examples of such a flow rate include a flow rate of several tens of mL / min to several tens of L / min, preferably a flow rate of 100 mL / min to 10 L / min, and more preferably a flow rate of 2 L / min to 9 L / min.

Further, the carbon dioxide decomposition reaction may proceed after the inside of the chamber 100 is depressurized. This makes it possible to more reliably promote the desorption of oxygen gas from the alkaline silicic oxide.

The heating temperature of the catalyst holding unit 11 may be appropriately set according to the catalytic activity temperature of the alkaline silicic oxide used, but is preferably kept at 350 ° C. or higher and 1000 ° C. or lower, for example. By setting the heating temperature (holding temperature) to 350 ° C. or higher and 1000 ° C. or lower, the decomposition reaction of carbon dioxide by the alkaline silicic acid can proceed more reliably. The heating temperature (holding temperature) of the catalyst holding unit 11 is more preferably 400 ° C. or higher and 600 ° C. or lower, and further preferably 450 ° C. or higher and 550 ° C. or lower.

In the catalyst holding unit 11 according to the present embodiment, in consideration of the size of the chamber 100 and the catalyst holding region 111, etc., a residence time sufficient to allow the carbon dioxide decomposition reaction to proceed can be secured. It is preferable to determine the flow rate of the carbon dioxide-containing gas introduced into the catalyst holding unit 11. At this time, it is more preferable to consider the flow rate so that the alkaline silicic acid oxide that has passed through the upper porous member 113B is settled and the carbon particles are scattered along with the flow.

For example, the carbon dioxide-containing gas introduction unit 20 preferably adjusts the flow velocity of the carbon dioxide-containing gas so that the carbon dioxide generated on the surface of the alkaline siliceous oxide is peeled off. Further, the carbon dioxide-containing gas introduction unit 20 has a carbon dioxide-containing gas with respect to the catalyst holding unit 11 so that the gas flow velocity on the gas introduction surface of the catalyst holding unit 11 is 0.5 m / min or more and 20 m / min or less. Is more preferable to introduce. When the gas flow velocity on the gas introduction surface of the catalyst holding unit 11 is within the above range, the carbon dioxide decomposition reaction can proceed in a more preferable state. The gas flow velocity on the gas introduction surface of the catalyst holding unit 11 is more preferably 1 m / min or more and 10 m / min or less, and further preferably 3 m / min or more and 9 m / min or less.

As described above, the chamber portion 10 according to the present embodiment has been described in detail with reference to FIGS. 2A to 3.

The carbon dioxide decomposition apparatus 1 according to the present embodiment has been described in detail above. According to the carbon dioxide decomposition apparatus 1 according to the present embodiment as described above, carbon dioxide can be continuously decomposed by heat treatment using an alkali silicic oxide as a catalyst.

(Second Embodiment)
Next, the carbon dioxide decomposition apparatus according to the second embodiment of the present invention will be described. In the carbon dioxide decomposition apparatus according to the present embodiment, quartz wool that functions as the carbon peeling mechanism is provided in the chamber portion 10 so as to be in a specific state.

(About the configuration of the chamber portion 10)
Subsequently, an example of the chamber portion 10 included in the carbon dioxide decomposition apparatus 1 according to the present embodiment will be described in more detail with reference to FIGS. 4 to 6. FIG. 4 is an explanatory diagram schematically showing an example of the configuration of the chamber portion of the carbon dioxide decomposition apparatus according to the present embodiment. 5A and 5B are explanatory views schematically showing an example of the configuration of the catalyst holding portion in the chamber portion according to the present embodiment. FIG. 6 is an explanatory diagram schematically showing another example of the configuration of the chamber portion of the carbon dioxide decomposition apparatus according to the present embodiment.

In the following, for convenience, the coordinate axes shown in FIG. 4 will be appropriately used for explanation. As shown in FIG. 4, the coordinate axes are such that the vertical upward direction is the Z-axis positive direction, and the plane defined by the X-axis and the Y-axis corresponds to the horizontal plane.

The chamber portion 10 according to the present embodiment includes a chamber 200 provided with the catalyst holding portion 11 and a heating facility 50 for heating at least the catalyst holding portion 11 of the chamber 200 to a desired temperature range.

Here, the heating equipment 50 is not particularly limited as long as it can at least heat the alkaline silicic acid oxide existing in the catalyst holding portion 11 in the chamber 200, and various heating furnaces, electric furnaces, and heating devices. Etc. can be used as appropriate. At this time, FIG. 4 shows a case where the catalyst holding portion 11 exists inside the heating facility 50, but if the alkaline silicic acid oxide existing in the catalyst holding portion 11 can be heated to a desired temperature, the catalyst holding portion 11 is held. The part 11 does not have to exist inside the heating equipment 50. Further, as the heating equipment 50 according to the present embodiment, the exhaust heat discharged from various high-temperature processes can be used as long as it is within the range of the catalyst activation temperature, and a heating device utilizing the exhaust heat can be used. It is also possible to use it.

Further, as the heating equipment 50 according to the present embodiment, it is also possible to use a heating device using renewable energy, and as a heating device using such renewable energy, a solar furnace that condenses sunlight. Can be exemplified. The heating temperature of a solar furnace often fluctuates depending on the weather conditions, but in the present invention, it can be used because the temperature range required for the carbon dioxide decomposition reaction is wide. Further, since the carbon dioxide decomposition according to the present invention is an endothermic reaction, it is possible to control the temperature of the catalyst holding unit 11 by controlling the amount of carbon dioxide that is circulated for decomposition. That is, if the heating capacity of the solar furnace used as the heating facility 50 is insufficient, the amount of carbon dioxide introduced is reduced, and conversely, if the heating capacity of the solar furnace is excessive, the amount of carbon dioxide introduced is increased to maintain the catalyst. The temperature of unit 11 may be controlled. Further, by using a solar furnace that collects sunlight as the heating facility 50, it is possible to realize a more environmentally friendly carbon dioxide decomposition device 1.

As shown schematically in FIG. 4, the chamber 200 used for the chamber portion 10 is provided with the catalyst holding portion 11 in a part of the region along the gas flow path direction. Here, FIG. 4 shows a case where the gas flow path direction in the chamber 200 is vertically upward (the Z-axis direction positive direction side in FIG. 4), but the gas flow path direction in the chamber 100 is shown. Is not particularly limited, and may be in the horizontal direction (X-axis direction or Y-axis direction in FIG. 4) or in an oblique direction. As described above, in each embodiment of the present invention, a solar furnace can be used as the heating facility 50, and a sideways trough type solar furnace can also be used as such a solar furnace. When a sideways trough type solar furnace is used, the sunlight condensing part becomes a horizontally held straight part of the trough type solar furnace, and the chamber part shown in FIG. 4 is sideways on this straight part of the tube. It will be installed as such a shape.

At least the catalyst holding portion 11 of the chamber 200 as shown in FIG. 4 is provided so as to be located inside the heating equipment 50. As a result, the alkaline silicic acid oxide held in the catalyst holding portion 11 is heated to the catalyst active temperature range and held at a desired temperature.

The carbon dioxide-containing gas supplied into the chamber 200 from the supply port 201 passes through the catalyst holding portion 11 provided in the chamber 200, and carbon dioxide is used as a catalyst by the alkaline silicic acid oxide located in the catalyst holding portion 11. The decomposition reaction of carbon dioxide proceeds. As a result, carbon particles and oxygen gas are generated from carbon dioxide in the carbon dioxide-containing gas. The generated carbon particles and oxygen gas pass through the chamber 200 and are discharged to the outside of the chamber 200 from the discharge port 203.

Here, the catalyst holding portion 11 according to the present embodiment has a catalyst holding region which is a region where the catalyst is held, and the catalyst holding region functions as a carbon peeling mechanism with the alkali silica oxide which is a catalyst. Includes quartz wool and.

Here, the quartz wool in the present embodiment is not particularly limited, and generally commercially available quartz wool can be used as it is. Examples of such quartz wool include commercially available products having a diameter of about 2 to 6 μm and a length of about several tens of mm.

In the carbon dioxide decomposition apparatus 1 according to the present embodiment, the alkali silicic acid oxide and the quartz wool are both present in the reaction system, so that the decomposition efficiency from _{CO 2 to C can be improved as compared with the case where the quartz wool is not present.} At the same time, the decomposition temperature of C can be lowered. The reason for this has not been fully elucidated at this time, but it is considered that the presence of quartz wool assists the decomposition of _{CO 2 absorbed by the material in the reaction system into C.} The mechanism at that time is unknown, but it is speculated that the _{presence of quartz wool may provide a field for CO 2} decomposition reaction at the contact interface between the alkali silicic oxide and quartz wool. ..

Here, the presence of the alkali silicic acid oxide and the quartz wool in the reaction system means that the carbon dioxide-containing gas is simultaneously present in the alkali silicic acid oxide and the quartz wool in a state where the materials in the reaction system are heated to a predetermined temperature. It refers to a form in which _{CO 2} is absorbed by the material in the reaction system when they come into contact with each other substantially at the same time.

The mixing ratio of the alkali silicic acid oxide and the quartz wool is not particularly limited, and the mixing ratio may be appropriately adjusted so that the desired decomposition temperature to C can be realized.

In such a catalyst holding region, the alkali silicic acid oxide and the quartz wool may exist in a mixed state with each other, or may exist in an unmixed state.

FIG. 5A is an enlarged schematic view showing a portion of the catalyst holding portion 11 provided in the chamber 200. In the example shown in FIG. 5A, the alkaline silicic acid oxide and the quartz wool form the catalyst holding region 211 in an unmixed state.

That is, in FIG. 5A, the upstream and downstream ends of the gas flow direction (Z-axis positive direction in FIG. 5A) in the region composed of alkaline silicic acid oxide (hereinafter, also referred to as alkaline silicic acid oxide region) 213. A layer made of quartz wool (hereinafter, also referred to as a quartz wool layer) is located in each of them. As a result, the alkali silicic acid region 213 is held in the catalyst holding portion 11. In the following, the quartz wool layer located on the upstream side in the gas flow direction will be referred to as the upstream quartz wool layer 215A, and the quartz wool layer located on the downstream side in the gas flow direction will be referred to as the downstream quartz wool layer 215B. And.

Further, the catalyst holding region 211 having the alkali silicate region 213, the upstream quartz wool layer 215A and the downstream quartz wool layer 215B is sandwiched by a pair of porous members 217 as schematically shown in FIG. 5A. Is preferable. Here, the porous member located on the upstream side of the catalyst holding region 211 is referred to as an upstream porous member 217A, and the porous member located on the downstream side of the catalyst holding region 211 is referred to as a downstream porous member 217B.

On the other hand, in FIG. 5B, the catalyst holding portion 11 is provided with a catalyst holding region 221 in which the alkali silicic acid oxide and the quartz wool are mixed with each other.

Further, the catalyst holding region 221 is preferably sandwiched by a pair of porous members 223 as schematically shown in FIG. 5B. Here, the porous member located on the upstream side of the catalyst holding region 221 is referred to as an upstream porous member 223A, and the porous member located on the downstream side of the catalyst holding region 221 is referred to as a downstream porous member 223B.

Here, the amount of the alkaline silicic oxide retained in the catalyst holding regions 211 and 221 is not particularly limited, and the size of the chamber 200 and the amount of carbon dioxide-containing gas to be treated (for example, per unit time) are not particularly limited. It may be appropriately set according to the amount of carbon dioxide-containing gas introduced) and the like. However, the alkaline silicic acid oxide is not so tightly held inside the catalyst holding regions 211 and 221 that it is difficult for the alkaline silicic acid particles to move, and the particles can move along with the gas flow. It is preferable that the particles are held in such a state.

In the catalyst holding region 211 according to the present embodiment as shown in FIG. 5A, the carbon particles generated on the particle surface of the alkali silicic oxide as a catalyst by the decomposition reaction of carbon dioxide form the downstream quartz wool layer 217B. It passes through the downstream quartz wool layer 217B while colliding with the quartz wool fibers multiple times. Due to such a collision, the carbon particles generated on the surface of the alkali silicic acid particles are separated from the surface of the alkaline silicic acid particles and are scattered along the gas flow to the discharge port 203 of the chamber 200.

Further, in the catalyst holding region 221 according to the present embodiment as shown in FIG. 5B, the carbon particles generated on the particle surface of the alkali siliceous oxide as a catalyst by the decomposition reaction of carbon dioxide are quartz wool existing in the layer. It passes through the catalyst holding region 221 while colliding with the fibers of the above a plurality of times. Due to such a collision, the carbon particles generated on the surface of the alkali silicic acid particles are separated from the surface of the alkaline silicic acid particles and are scattered along the gas flow to the discharge port 203 of the chamber 200.

With the configuration of the catalyst holding regions 211 and 221 as described above, in the carbon dioxide decomposition apparatus 1 according to the present embodiment, the carbon particles generated on the surface of the alkali silicic acid oxide are peeled off, so that the alkali silicic acid oxide as a catalyst is lost. It suppresses activity and enables continuous decomposition of carbon dioxide.

In addition to the alkaline silicic acid oxide and quartz wool, the catalyst holding regions 211 and 221 according to the present embodiment may contain a catalyst scattering preventive material for preventing excessive scattering of the alkaline silicic acid oxide. .. Examples of such a catalyst shatterproof material include at least one of an amorphous fiber containing alumina and silica as main components and a crystalline fiber containing alumina and silica as main components. The content of the catalyst shatterproof material is not particularly limited, and can be appropriately adjusted within a range that does not hinder the progress of the carbon dioxide decomposition reaction.

Further, as shown in FIGS. 5A and 5B, the catalyst holding region 211 is preferably held by a pair of porous members 217, and the catalyst holding region 221 is held by a pair of porous members 223. Is preferable. As a result, the catalyst holding regions 211 and 221 can be positioned more stably in the chamber 200.

Each of these porous members 217 and 223 is provided with pores (not shown) having a pore diameter smaller than the average particle diameter of the alkali silicic oxide. More specifically, the downstream porous members 217B and 223B are provided with pores that are smaller than the average particle size of the alkali silicic oxide and larger than the average particle size of the carbon particles to be produced. By providing such pores, the gas can permeate the entire catalyst holding regions 211 and 221 and the alkali silicic acid oxide as a catalyst can more stably hold the catalyst by the upstream porous members 217A and 223A. It is held in the regions 211 and 221. Further, even if the alkaline silicic acid oxide on which the carbon particles generated by the reaction adheres to the surface passes through the downstream quartz wool layer 215B and the catalyst holding region 221, the downstream porous member 217B rides on the flow of the supplied gas. , 223B, the generated carbon particles are more reliably separated from the surface of the alkali silicic acid oxide, pass through the downstream porous members 217B and 223B, and scatter toward the discharge port 203 of the chamber 200. ..

The materials of the porous members 217 and 223 are not particularly limited, and various materials may be used as long as they have sufficient strength even at the temperature at which the catalyst holding portion 11 is held. It is possible to use a non-metal material or a metal material. Examples of such a material include various porous bodies such as a porous body of a glass plate and a porous body of various ceramics, and various mesh-like materials such as a stainless steel wire mesh.

Further, the density of the pores provided in the porous members 217 and 223 is determined by the amount and pressure of the carbon dioxide-containing gas to be introduced into the catalyst holding regions 211 and 221 and the residence time of the carbon dioxide-containing gas in the catalyst holding regions 211 and 221. It may be set as appropriate according to the situation. Further, the size of the hole portion, the abundance density of the hole portion, and the like may be the same value for the upstream porous member and the downstream porous member, or may be different values.

In the catalyst holding portion 11 having the catalyst holding regions 211 and 221 as described above, the atmosphere at the time of reaction is preferably a non-oxidizing atmosphere. By creating such an atmosphere, it is possible to more reliably prevent the produced carbon from being oxidized. Examples of such a non-oxidizing atmosphere include an atmosphere of an inert gas such as an Ar atmosphere and a nitrogen atmosphere. The purity of the non-oxidizing gas used may be the purity of a general gas cylinder (for example, 99.99%). With this degree of purity, the oxidation of the produced carbon can be virtually ignored. The flow rate of the non-oxidizing gas is not particularly specified, and may be a small amount from an economical point of view. For the purpose of preventing the pressure inside the chamber 200 from rising or being damaged due to heating, the flow rate may be set so that the non-oxidizing gas does not flow back from the exhaust port. Examples of such a flow rate include a flow rate of several tens of mL / min to several tens of L / min, preferably a flow rate of 100 mL / min to 10 L / min, and more preferably a flow rate of 2 L / min to 9 L / min.

Further, the carbon dioxide decomposition reaction may proceed after the inside of the chamber 200 is depressurized. This makes it possible to more reliably promote the desorption of oxygen gas from the alkaline silicic oxide.

The heating temperature of the catalyst holding unit 11 may be appropriately set according to the catalytic activity temperature of the alkaline silicic oxide used, but is preferably kept at 350 ° C. or higher and 1000 ° C. or lower, for example. By setting the heating temperature (holding temperature) to 350 ° C. or higher and 1000 ° C. or lower, the decomposition reaction of carbon dioxide by the alkaline silicic acid can proceed more reliably. The heating temperature (holding temperature) of the catalyst holding unit 11 is more preferably 400 ° C. or higher and 600 ° C. or lower, and further preferably 450 ° C. or higher and 550 ° C. or lower.

In the catalyst holding unit 11 according to the present embodiment, considering the sizes of the chamber 200 and the catalyst holding regions 211 and 221 and the like, it is possible to secure a residence time sufficient to allow the carbon dioxide decomposition reaction to proceed. It is preferable to determine the flow rate of the carbon dioxide-containing gas introduced into the catalyst holding unit 11.

For example, the carbon dioxide-containing gas introduction unit 20 preferably adjusts the flow velocity of the carbon dioxide-containing gas so that the carbon dioxide generated on the surface of the alkaline siliceous oxide is peeled off. Further, the carbon dioxide-containing gas introduction unit 20 has a carbon dioxide-containing gas with respect to the catalyst holding unit 11 so that the gas flow velocity on the gas introduction surface of the catalyst holding unit 11 is 0.5 m / min or more and 20 m / min or less. Is more preferable to introduce. When the gas flow velocity on the gas introduction surface of the catalyst holding unit 11 is within the above range, the carbon dioxide decomposition reaction can proceed in a more preferable state. The gas flow velocity on the gas introduction surface of the catalyst holding unit 11 is more preferably 1 m / min or more and 10 m / min or less, and further preferably 3 m / min or more and 9 m / min or less.

<Modification example>
Subsequently, a modified example of the chamber portion 10 according to the present embodiment will be briefly described with reference to FIG. FIG. 6 is an explanatory diagram schematically showing another example of the configuration of the chamber portion of the carbon dioxide decomposition apparatus according to the present embodiment.

As shown schematically in FIG. 6, the chamber portion 10 according to this modification may be composed of a chamber 200'having a tapered portion 205. In this case, the gas flow direction in the chamber 200'is from the lower vertical direction to the upper direction (Z in FIG. 6) in order to realize the settling function of the alkaline silicic oxide by the tapered portion 205 as described below. (Axial positive direction) is preferable.

In such a chamber 200', a tapered portion 205 is provided on the upstream side of the chamber 200'(the negative direction side of the Z axis in FIG. 6) so that the internal region expands toward the upper side in the vertical direction (the positive direction of the Z axis). Further, the catalyst holding portion 11 having a structure as shown in FIG. 5A or FIG. 5B is provided at a portion corresponding to the tapered portion 205.

The specific gravities of the alkaline silicic oxide and the produced carbon particles are significantly different. Further, since the catalyst holding portion 11 is provided in the tapered portion 205, the flow velocity of the gas passing through the tapered portion 205 gradually decreases toward the upper side in the vertical direction (the positive direction side of the Z axis). Therefore, even if the alkaline silicic acid oxide passes through the catalyst holding regions 211 and 221, the alkaline silicic acid oxide is separated by specific gravity and settles toward the catalyst holding portion 11. That is, in the taper portion 205 according to the present embodiment, the alkali silicic acid particles scattered from the catalyst holding regions 211 and 221 can be precipitated to the catalyst holding regions 211 and 221 by the taper shape of the taper portion 205. is there.

As described above, the chamber portion 10 according to the present embodiment has been described in detail with reference to FIGS. 4 to 6.

The carbon dioxide decomposition apparatus 1 according to the present embodiment has been described in detail above. According to the carbon dioxide decomposition apparatus 1 according to the present embodiment as described above, carbon dioxide can be continuously decomposed by heat treatment using an alkali silicic oxide as a catalyst.

Hereinafter, the carbon dioxide decomposition apparatus according to the present invention will be specifically described with reference to Examples and Comparative Examples. The examples shown below are merely examples of the carbon dioxide decomposition apparatus according to the present invention, and the carbon dioxide decomposition apparatus according to the present invention is not limited to the following examples.

(Experimental Example 1)
In Experimental Example 1 shown below, the carbon dioxide decomposition apparatus according to the first embodiment of the present invention was verified.

<Example>
By the above-mentioned alkali silicate synthesis method, 3.4 Li ₂ O · SiO ₂ and 4.4 K ₂ O · SiO ₂ were synthesized as catalyst substances. The massive 3.4 Li ₂ O · SiO ₂ and 4.4 K ₂ O · SiO ₂ were pulverized in a mortar and the particle size was adjusted to 0.30 mm to 0.85 mm using a sieve. When _{about 3 g of each of the 3.4 Li 2} O · SiO ₂ and the 4.4 K ₂ O · SiO ₂ were mixed, the bulk of these was about 5 cm ³ .

Next, as a catalyst holding case, which is an example of the catalyst holding portion, a stainless steel wire mesh having an opening of 0.15 mm was used to manufacture a cylinder having an outer diameter of about 37 mm and a height of about 47 mm. The volume of this catalyst holding case was about 50.5 cm ³ , which was about 10.1 times the bulk of the catalyst. The catalyst was charged into the catalyst holding case to form a catalyst holding portion. Each of the 3.4 Li ₂ O · SiO ₂ particles and the 4.4K ₂ O · SiO ₂ particles were in a moving state in the catalyst holding case.

The catalyst holding portion thus obtained was fixed to the central portion of a vertically fixed quartz tube having an inner diameter of about 38 mm, a wall thickness of about 2.3 mm, and a total length of 300 mm. As a fixing method, a quartz tube having an inner diameter of about 29 mm and a wall thickness of about 2 mm was inserted inside the quartz tube and sandwiched and fixed from above and below. An openable and closable resistance heating furnace was installed in the area of the catalyst holding portion having a height of 47 mm and a region having a total length of 26.5 mm and a total length of 100 mm to enable heating of the catalyst portion. A chamber having a stainless steel taper was attached above the quartz tube having the catalyst holding portion. That is, in this embodiment, the chamber portion 10 having an outline shape as schematically shown in FIG. 2A was manufactured.

The lower surface of the chamber has an inner diameter of 38 mm, and the chamber has an upwardly expanding tapered shape having an inner diameter of 200 mm above 300 mm. It has a tapered shape (that is, a reverse tapered shape), and this is the upper surface of the chamber.

A vertically fixed upper quartz tube having an inner diameter of about 38 mm, a wall thickness of about 2.3 mm, and a total length of 100 mm was attached to the upper surface of this chamber. In the center of this upper quartz tube, a disk-shaped part with a thickness of about 10 mm is formed by sandwiching about 1 g of commercially available quartz wool with a diameter of 2 to 6 μm with a disk-shaped stainless steel wire mesh with an outer diameter of about 37 mm and 16 mesh from above and below. It was decided to attach and collect the carbon particles generated from the quartz wool of this part. The fixing method is the same as described above. The part composed of these parts functions as a dust collector.

A lower flange made of aluminum was attached to the lower surface of the quartz tube having a catalyst holding region, and an upper flange was attached to the upper surface of the quartz tube having a carbon particle collecting portion. A gas inlet was attached to the lower flange, a gas outlet was attached to the upper flange, and a predetermined flow meter and a gas cylinder were connected to the gas inlet via a gas pipe. As described above, since the quartz tube is the outer wall and the carbon particle collecting portion where the quartz wool is fixed is located outside the heating furnace, it can be always visually observed during the experiment.

Helium gas was introduced from the gas inlet at the bottom of the reactor at a flow rate of 6 L / min, the heating furnace was energized, and the catalyst portion was heated to 500 ° C. at 15 ° C./min. The gas flow velocity of the catalyst portion at this time is calculated to be 5.3 m / min. After reaching 500 ° C., the helium gas was switched _{to a helium-balanced 5% CO 2 gas.} The flow rate remains at 6 L / min and there is no change in the gas flow rate. About 2 minutes after switching to 5% CO ₂ gas, the quartz wool in the carbon particle collection part began to turn black, and the blackness increased with the passage of time. After 30 minutes had passed, the gas was switched to helium gas again, the energization of the heating furnace was stopped, the mixture was cooled to room temperature, and the helium gas was stopped.

When the quartz wool in the carbon particle collection part was taken out, black matter was attached. When 0.1 g of black matter was recovered and carbon-analyzed by the combustion infrared absorption method, 98% or more was carbon. The only carbon source in the reaction vessel is the introduced CO ₂ , and it is considered that _{CO 2} was reduced to carbon by the catalyst. In order to quantify the carbon adhering to the quartz wool, when the remaining amount other than 0.1 g was oxidized together with the quartz wool at 500 ° C. in the air, the black matter disappeared and the weight was reduced by about 0.5 g. there were. From these values, the total amount of black matter adhered to the carbon particle collecting part was about 0.6 g. Since the _{total amount of CO 2} circulated was 9 L, the carbon recovery efficiency at the carbon particle collection section was about 12.4% of the amount of carbon contained _{in CO 2, assuming that all black substances were produced carbon.} In addition, a slight amount of black matter was attached to the catalyst particles of the catalyst holding portion, and when 0.03 g of this black matter was recovered and carbon-analyzed by the combustion infrared absorption method, 98% or more was also carbon. Further, when the entire catalyst holding portion was oxidized in air at 500 ° C., the black matter disappeared and the weight was reduced by about 0.05 g, and the total amount of the black matter adhering to the catalyst holding portion was 0. It was 08 g. Since the _{total amount of CO 2} circulated was 9 L, the carbon adhesion rate to the catalyst holding portion was about 1.7% of the amount of carbon contained _{in CO 2, assuming that all black substances were produced carbon.}

Further, the catalyst particles were slightly adhered to the outer upper surface of the catalyst holding case. The catalyst particles in the catalyst holding part seemed to be slightly crushed by colliding with the stainless steel wire mesh, and some of them were 0.3 mm or less, and some of them were smaller than the opening of 0.1 mm of the catalyst holding case. There was also. However, due to the effect of lowering the flow velocity of the tapered portion of the upper stainless chamber, the catalyst particles protruding from the catalyst holding case seem to fall into the upper surface of the catalyst holding case or into the catalyst holding case, and the inner wall of the stainless chamber and the carbon particle collecting portion. No catalyst particles were attached to the surface.

As described above, _{it was found that CO 2} can be decomposed into carbon by only one step of distributing _{CO 2 to the heated catalyst.} It was also clarified that _{CO 2} was continuously decomposed because the adhesion of black matter to the quartz wool of the carbon particle collecting part increased with the passage of time.

<Comparison example>
A reactor was manufactured in the same manner as in the above embodiment except that the stainless steel chamber attached above the quartz tube having the catalyst holding portion had a cylindrical shape with an inner diameter of 38 mm and a length of 600 mm. An experiment exactly the same as in the examples was performed. Similar to the above embodiment, the carbon particle collecting portion to which the quartz wool is fixed can always be visually observed during the experiment because the quartz tube is the outer wall and is located outside the heating furnace. It was.

Helium gas was introduced at a flow rate of 6 L / min from the gas inlet at the bottom of the reactor, the heating furnace was energized, and the catalyst portion was heated to 500 ° C. at a heating rate of 15 ° C./min. The gas flow velocity of the catalyst portion at this time was calculated to be 5.3 m / min. After the temperature reached 500 ° C., helium gas was switched to _{helium-balanced 5% CO 2 gas.} The flow rate remained at 6 L / min and there was no change in gas flow rate. About 2 minutes after switching to 5% CO ₂ gas, the quartz wool in the carbon particle collection part began to turn slightly gray, but the color did not change immediately, and on the contrary, it was finely crushed. Adhesion of white catalyst particles began. The amount of the catalyst particles attached increased with the passage of time. After 30 minutes had passed, the gas was switched to helium gas again, the energization of the heating furnace was stopped, the mixture was cooled to room temperature, and the helium gas was stopped.

When the quartz wool of the carbon particle collecting part was taken out, only a trace amount of gray part was formed. As a precaution, all of this part was carbon-analyzed by the combustion infrared absorption method, but no carbon was detected. The lower limit of carbon analysis in the combustion infrared absorption method is 5 μg, and even if carbon is produced, the amount of carbon produced is less than 5 μg. Even carbon believe in the greatest amount was produced 5 [mu] g, since CO ₂ was circulated in the reaction vessel is a 9L total, rather only about 0.0001% of the amount of carbon contained in the CO _2, CO ₂ It was an impractical value for decomposition.

The reason why the CO ₂ decomposition did not proceed in this way is that there is no tapered structure at the top of the catalyst holding part and the gas flow velocity does not decrease, so there is no function to return the finely scattered catalyst to the catalyst holding part, and the catalyst substance. It is probable that the 3.4 Li ₂ O · SiO ₂ and the 4.4 K ₂ O · SiO ₂ were widely scattered, the opportunity for contact between the two was lost, and the catalytic performance could not be exhibited.

(Experimental Example 2)
In Experimental Example 2 shown below, the carbon dioxide decomposition apparatus according to the second embodiment of the present invention was verified.

<Example>
By the above-mentioned alkali silicate synthesis method, 3.4 Li ₂ O · SiO ₂ and 4.4 K ₂ O · SiO ₂ were synthesized as catalyst substances. The massive 3.4 Li ₂ O · SiO ₂ and 4.4 K ₂ O · SiO ₂ were pulverized in a mortar and the particle size was adjusted to 0.30 mm to 0.85 mm using a sieve. About 3 g of each of the 3.4 Li ₂ O · SiO ₂ and the 4.4 K ₂ O · SiO ₂ were mixed and lightly sandwiched from above and below with commercially available quartz wool having a diameter of 2 μm to 6 μm. The quartz wool used is about 0.5 g each on the top and bottom. These were lightly sandwiched from above and below with a disc-shaped stainless steel wire mesh having an outer diameter of about 37 mm and 16 mesh, and the periphery of the upper and lower stainless steel wire mesh was connected with a stainless wire. The total thickness of these is about 20 mm at the central portion of the disc-shaped stainless steel wire mesh. Each of the 3.4 Li ₂ O · SiO ₂ particles and the 4.4K ₂ O · SiO ₂ particles were in a state of moving between the quartz wool sandwiched from above and below.

The catalyst holding portion thus obtained was fixed to the central portion of a vertically fixed quartz tube having an inner diameter of about 38 mm, a wall thickness of about 2.3 mm, and a total length of 640 mm. As a fixing method, a quartz tube having an inner diameter of about 29 mm and a wall thickness of about 2 mm was inserted inside the quartz tube and sandwiched and fixed from above and below.

Further, a disk-shaped part having a thickness of about 10 mm, which is obtained by sandwiching about 1 g of quartz wool from above and below with a disk-shaped stainless steel wire mesh having an outer diameter of about 37 mm and 16 mesh, is attached to a position about 200 mm above the catalyst particles. It was decided to collect the generated carbon particles with the quartz wool of. The fixing method is the same as described above. The part composed of these parts functions as a dust collector.

Flange made of aluminum is attached to the top and bottom of the vertically fixed outer quartz tube, a gas inlet is attached to the lower flange, and a gas outlet is attached to the upper flange. A predetermined flow meter and gas cylinder were connected via the gas pipe. An openable and closable resistance heating furnace was installed in a region 150 mm above and below the catalyst fixing portion and a total length of 300 mm so that the catalyst portion could be heated. The carbon particle collector, in which only quartz wool was fixed, was located outside the heating furnace and was always visible during the experiment.

Helium gas was introduced from the gas inlet at the bottom of the reactor at a flow rate of 6 L / min, the heating furnace was energized, and the catalyst portion was heated to 500 ° C. at 15 ° C./min. The gas flow velocity of the catalyst portion at this time is calculated to be 5.3 m / min. After reaching 500 ° C., the helium gas was switched _{to a helium-balanced 5% CO 2 gas.} The flow rate remains at 6 L / min and there is no change in the gas flow rate. About 2 minutes after switching to 5% CO ₂ gas, the quartz wool in the carbon particle collection part began to turn black, and the blackness increased with the passage of time. After 30 minutes had passed, the gas was switched to helium gas again, the energization of the heating furnace was stopped, the mixture was cooled to room temperature, and the helium gas was stopped.

When the quartz wool in the carbon particle collection part was taken out, black matter was attached. When 0.1 g of black matter was recovered and carbon-analyzed by the combustion infrared absorption method, 98% or more was carbon. The only carbon source in the reaction vessel is the introduced CO ₂ , and it is considered that _{CO 2} was reduced to carbon by the catalyst. In order to quantify the carbon adhering to the quartz wool, when the remaining amount other than 0.1 g was oxidized together with the quartz wool at 500 ° C. in the air, the black matter disappeared and the weight was reduced by about 0.45 g. there were. From these values, the total amount of black matter adhered to the carbon particle collecting portion was about 0.55 g. Since the _{total amount of CO 2} circulated was 9 L, the carbon recovery efficiency at the carbon particle collection section was about 11.4% of the amount of carbon contained _{in CO 2, assuming that all black substances were produced carbon.} In addition, the quartz wool sandwiching the catalyst was also slightly blackened, and when 0.05 g of this black material was recovered and carbon-analyzed by the combustion infrared absorption method, 98% or more was also carbon. When the quartz wool in this part was also oxidized by the same method as above, the black matter disappeared and the weight was reduced by about 0.1 g, and the total amount of the black matter adhered to the catalyst holding portion was 0. It was 15 g. Since the _{total amount of CO 2} circulated was 9 L, the carbon adhesion rate to the catalyst holding portion was about 3.1% of the amount of carbon contained _{in CO 2, assuming that all black substances were produced carbon.}

As described above, _{it was found that CO 2} can be decomposed into carbon by only one step of distributing _{CO 2 to the heated catalyst.} It was also clarified that _{CO 2} was continuously decomposed because the adhesion of black matter to the quartz wool of the carbon particle collecting part increased with the passage of time.

<Comparison example>
A reactor was manufactured in the same manner as in the above-mentioned Examples except that quartz wool was not used for the catalyst holding portion and the opening of the stainless steel wire mesh of the catalyst holding portion was changed. _{That is, about 3 g of each of 3.4 Li 2} O · SiO ₂ and 4.4 K ₂ O · SiO ₂ having a particle size of 0.30 mm to 0.85 mm are mixed, and quartz wool is not used for the catalyst holding portion, and the outer diameter is not used. It was lightly sandwiched from above and below only with a disc-shaped stainless steel wire mesh of about 37 mm, 165 mesh, and a mesh size of 0.104 mm, and the circumference of the upper and lower stainless steel wire mesh was tied with a stainless wire. The total thickness of these is about 10 mm at the central portion of the disc-shaped stainless steel wire mesh. Each of the 3.4 Li ₂ O · SiO ₂ particles and the 4.4K ₂ O · SiO ₂ particles were in a state of moving between the disk-shaped stainless steel wire mesh sandwiched from above and below. Further, as in the above embodiment, the carbon particle collecting portion to which the quartz wool is fixed has a quartz tube as an outer wall and is located outside the heating furnace, so that it can always be visually observed during the experiment. Met.

Helium gas was introduced at a flow rate of 6 L / min from the gas inlet at the bottom of the reactor, the heating furnace was energized, and the catalyst portion was heated to 500 ° C. at a heating rate of 15 ° C./min. The gas flow velocity of the catalyst portion at this time was calculated to be 5.3 m / min. After the temperature reached 500 ° C., helium gas was switched to _{helium-balanced 5% CO 2 gas.} The flow rate remained at 6 L / min and there was no change in gas flow rate. About 2 minutes after switching to 5% CO ₂ gas, the quartz wool in the carbon particle collection part began to turn slightly gray, but the color did not change immediately, and on the contrary, it was finely crushed. Adhesion of white catalyst particles began. The amount of the catalyst particles attached increased with the passage of time. After 30 minutes had passed, the gas was switched to helium gas again, the energization of the heating furnace was stopped, the mixture was cooled to room temperature, and the helium gas was stopped.

When the quartz wool of the carbon particle collecting part was taken out, only a trace amount of gray part was formed. As a precaution, all of this part was carbon-analyzed by the combustion infrared absorption method, but no carbon was detected. The lower limit of carbon analysis in the combustion infrared absorption method is 5 μg, and even if carbon is produced, the amount of carbon produced is less than 5 μg. Even carbon believe in the greatest amount was produced 5 [mu] g, since CO ₂ was circulated in the reaction vessel is a 9L total, rather only about 0.0001% of the amount of carbon contained in the CO _2, CO ₂ It was an impractical value for decomposition.

The reason why the CO ₂ decomposition did not proceed in this way is that the quartz wool was not present in the catalyst holding part, so that the finer catalyst particles were scattered and the opportunity for the two to come into contact with each other in the heating part was lost. It is probable that the catalytic performance could not be exhibited.

Although the preferred embodiments of the present invention have been described in detail with reference to the accompanying drawings, the present invention is not limited to such examples. It is clear that a person having ordinary knowledge in the field of technology to which the present invention belongs can come up with various modifications or modifications within the scope of the technical idea described in the claims. , These are also naturally understood to belong to the technical scope of the present invention.

1 Carbon dioxide decomposition device 10 Chamber part 20 Carbon dioxide-containing gas introduction part 30 Dust collector 40 Dehydrator 50 Heating equipment 100 Chamber 101 Tapered part 103 Non-tapered part 105 Reverse tapered part 107 Supply port 109 Discharge port 111 Catalyst holding area 113 Porous member 113A Lower perforated member 113B Upper perforated member 200, 200' Chamber 201 Supply port 203 Discharge port 205 Tapered part 211,221 Catalyst holding area 213 Alkaline siliceous oxide area 215 Quartz wool layer 215A Upstream quartz wool layer 215B Downstream quartz wool layer 217, 223 Perforated member 217A, 223A Upstream perforated member 217B, 223B Downstream perforated member 251 Perforated member 251A Upstream perforated member 251B Downstream perforated member

Claims (16)

Alkaline silicic acid is used as a catalyst, and by heating the catalyst holding part, which is the part where the alkaline silicic oxide is held, it is used for the decomposition treatment of decomposing carbon dioxide passing through the catalyst holding part into carbon and oxygen. It ’s a device,
A catalyst holding region which is a region where the catalyst is held, which contains at least the alkali silicic acid oxide, and a catalyst holding region.
A carbon peeling mechanism for peeling the carbon generated on the surface of the alkali silicic acid oxide from the surface,
A chamber in which the catalyst holding region and the carbon peeling mechanism are housed, at least the catalyst holding region is heated to a predetermined temperature by a heating facility, and the generated carbon and the oxygen are discharged from the discharge port. When,
A carbon dioxide-containing gas introduction unit that introduces carbon dioxide-containing gas into the catalyst holding region in the chamber, and a carbon dioxide-containing gas introduction unit.
A dust collector that collects the carbon discharged from the discharge port, and
A carbon dioxide decomposition device equipped with. The chamber has a tapered portion whose internal region expands toward the upper side in the vertical direction, and the catalyst holding region is provided in the tapered portion or below the tapered portion.
As the carbon exfoliation mechanism, the pores are located at the upper end in the vertical direction and the lower end in the vertical direction of the catalyst holding region, respectively, and have a pore diameter smaller than the average particle diameter of the alkali siliceous oxide particles. The carbon dioxide decomposition apparatus according to claim 1, further comprising a pair of porous members provided. The carbon dioxide decomposition apparatus according to claim 2, wherein in the catalyst holding region, a fluidized bed of the alkaline silicic acid oxide is formed by the carbon dioxide-containing gas introduced. The volume of the catalyst holding region is 2 times or more and 100 times or less the volume of the alkaline silicic oxide housed in the catalyst holding region.
The carbon dioxide decomposition apparatus according to claim 2 or 3, wherein the carbon dioxide-containing gas causes the alkali silicic acid particles to collide with the porous member located on the upper side in the vertical direction. The carbon dioxide decomposition apparatus according to any one of claims 2 to 4, wherein the alkali silicic acid particles scattered from the catalyst holding region are settled to the catalyst holding region due to the tapered shape of the tapered portion. Claims 2 to 5 further include at least one of an amorphous fiber containing alumina and silica as a main component, a crystalline fiber containing alumina and silica as a main component, and quartz wool. The carbon dioxide decomposition apparatus according to any one of the above items. The carbon dioxide decomposition apparatus according to claim 1, wherein the catalyst holding region further contains quartz wool that functions as the carbon exfoliation mechanism. The seventh aspect of the present invention, wherein in the catalyst holding region, the alkali silicic oxide is retained by locating the quartz wool at the upstream and downstream ends of the alkaline silicic oxide in the gas flow direction, respectively. Carbon dioxide decomposition device. The carbon dioxide decomposition apparatus according to claim 7 or 8, wherein in the catalyst holding region, the alkali silicic acid oxide is held in a state where the alkali silicic acid oxide particles and the quartz wool are mixed. The catalyst holding region is held inside the chamber by a pair of porous members provided with pores having a pore diameter smaller than the average particle size of the alkali silicic acid particles, according to claims 7 to 9. The carbon dioxide decomposition apparatus according to any one of the following items. Any of claims 7 to 10, wherein the catalyst holding region further contains at least one of an amorphous fiber containing alumina and silica as main components and a crystalline fiber containing alumina and silica as main components. The carbon dioxide decomposition apparatus according to item 1. The gas flow direction in the chamber is from the lower side to the upper side in the vertical direction, and the upstream side of the chamber is provided with a tapered portion whose internal region expands toward the upper side in the vertical direction.
The catalyst holding region is provided at a portion corresponding to the tapered portion.
The carbon dioxide decomposition apparatus according to any one of claims 7 to 11, wherein the alkali silicic acid particles scattered from the catalyst holding region are settled to the catalyst holding region due to the tapered shape of the tapered portion. The heating facility is a horizontal trough type solar furnace that heats a heating target by condensing sunlight, and the catalyst holding region is located in a horizontally held linear condensing portion of the trough type solar furnace. The carbon dioxide decomposition apparatus according to any one of claims 7 to 11, which is provided. The carbon dioxide decomposition apparatus according to any one of claims 1 to 12, wherein the heating facility is a solar furnace that heats a heating target by condensing sunlight. The carbon dioxide decomposition apparatus according to any one of claims 1 to 14, wherein the flow rate of the carbon dioxide-containing gas introduced from the carbon dioxide-containing gas introduction unit is controlled according to the heating capacity of the heating equipment. .. The carbon dioxide decomposition device according to any one of claims 1 to 15, wherein a dehydrator for removing water in the carbon dioxide-containing gas is provided on the upstream side of the carbon dioxide-containing gas introduction unit.

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