Adsorption structure and gas recovery device

Abstract

Provided is an adsorption structure including: an adsorbent 1 capable of adsorbing a gas to be captured that is contained in a gas to be treated and of desorbing the adsorbed gas; and a porous protective material 2 provided to the surface of the adsorbent 1 which is to be exposed to the gas being treated. The protective material 2 has a porosity of 30-80% and is permeable to the gas to be captured, due to concentration diffusion.

Description

Adsorption structure and gas recovery device

[0001] The present invention relates to an adsorptive structure and a gas recovery device.

[0002] In recent years, efforts have been made to separate and capture acidic gases contained in the atmosphere in order to reduce environmental impact. The main example of such an acidic gas is carbon dioxide (hereinafter sometimes referred to as "CO2"), which causes global warming. The Carbon Dioxide Capture, Utilization and Storage (CCUS) cycle is a well-known example of such an approach.

[0003] A gas separation unit equipped with an adsorption section has been proposed as an apparatus used for separating and recovering target gases such as CO2 (see, for example, Patent Document 1). The adsorption section of the gas separation unit is formed by disposing an adsorbent material between two sheets made of a flexible fabric material that is gas-permeable but impermeable to the adsorbent. In this gas separation unit, the adsorbent material contained in the adsorption section adsorbs the target gas at a predetermined adsorption temperature and desorbs the target gas at a desorption temperature that exceeds the adsorption temperature.

[0004] In a gas separation unit such as that described in Patent Document 1, a desorbed gas (purge gas) heated to a desorption temperature is passed through an adsorption section that has adsorbed the target gas, and the target gas is recovered together with the desorbed gas. In this method of recovering the target gas, thermal energy is transferred from the passing desorbed gas to the adsorption section. However, in the gas separation unit described in Patent Document 1, the desorbed gas passes through a flexible fabric material and directly contacts the adsorbent, which is prone to temperature differences between the surface and interior of the adsorbent. It is generally known that such temperature differences within components can cause peeling or cracking due to differences in thermal expansion within the components (e.g., Patent Document 2). Therefore, repeated use of the gas separation unit can cause partial peeling or cracking of the adsorbent due to differences in thermal expansion, potentially resulting in the adsorbent leaking to the outside.

[0005] International Publication No. 2014 / 170184 Japanese Patent Application Laid-Open No. 2018-172258

[0006] The present invention has been made to solve the above problems, and aims to provide an adsorptive structure that is less likely to undergo partial peeling or cracking even when repeatedly heated. Another aim of the present invention is to provide a gas recovery device that can prevent the adsorbent from leaking to the outside.

[0007] As a result of intensive research aimed at solving the above-mentioned problems, the inventors discovered that providing a specific protective material on the surface side of the adsorbent that is exposed to the process gas reduces the temperature difference within the adsorbent and alleviates the thermal expansion difference, leading to the completion of the present invention. That is, the present invention is exemplified as follows.

[0008] [1] An adsorptive structure comprising: an adsorbent capable of adsorbing a target gas to be captured contained in a process gas and desorbing the adsorbed target gas to be captured; and a porous protective material provided on the surface side of the adsorbent exposed to the process gas, wherein the protective material has a porosity of 30 to 80% and is permeable to the target gas to be captured by concentration diffusion.

[0009] [2] The adsorptive structure according to [1], further comprising a carrier positioned so as to sandwich the adsorbent between the carrier and the protective material.

[0010] [3] The adsorptive structure according to [1], wherein the adsorbent is encapsulated in the protective material.

[0011] [4] The adsorptive structure according to any one of [1] to [3], wherein the protective material has open cells.

[0012] [5] The adsorptive structure according to any one of [1] to [4], wherein the adsorptive structure is in a plate shape or a honeycomb shape.

[0013] [6] The adsorptive structure according to any one of [1] to [4], wherein the adsorptive structure is in the form of pellets.

[0014] [7] The adsorptive structure according to any one of [1] to [6], wherein the target gas to be captured is an acidic gas.

[0015] [8] The adsorptive structure according to any one of [1] to [7], wherein the target gas to be captured is carbon dioxide.

[0016] [9] A gas recovery device for recovering and releasing a target gas contained in a treatment gas, the gas recovery device comprising the adsorptive structure according to any one of [1] to [8].

[0017] According to the present invention, it is possible to provide an adsorptive structure that is resistant to partial peeling or cracking even when repeatedly heated. Also, according to the present invention, it is possible to provide a gas recovery device that can suppress the outflow of the adsorbent to the outside.

[0018] FIG. 1 is a schematic cross-sectional view of an adsorptive structure according to one embodiment of the present invention; FIG. 2 is a schematic cross-sectional view of an adsorptive structure according to another embodiment of the present invention; FIG. 3 is a schematic cross-sectional view of an adsorptive structure according to another embodiment of the present invention; FIG. 4 is a schematic cross-sectional view of an adsorptive structure according to another embodiment of the present invention; FIG. 5 is a schematic cross-sectional view of an adsorptive structure according to another embodiment of the present invention; FIG. 6 is a schematic cross-sectional view of an adsorptive structure according to another embodiment of the present invention; FIG. 7 is a schematic cross-sectional view of an adsorptive structure according to another embodiment of the present invention; FIG. 8 is a schematic cross-sectional view of an adsorptive structure according to another embodiment of the present invention; FIG. 9 is a schematic cross-sectional view of an adsorptive structure according to another embodiment of the present invention; FIG. 10 is a schematic cross-sectional view of an adsorptive structure according to another embodiment of the present invention; FIG. 11 is a schematic cross-sectional view of an adsorptive structure according to another embodiment of the present invention; FIG. 12 is a schematic cross-sectional view of an adsorptive structure according to another embodiment of the present invention; FIG. 13 is a schematic cross-sectional view of an adsorptive structure according to another embodiment of the present invention; FIG. 14 is a schematic cross-sectional view of an adsorptive structure according to another embodiment of the present invention; FIG. 15 is a schematic cross-sectional view of an adsorptive structure according to another embodiment of the present invention; FIG. 16 is a schematic cross-sectional view of an adsorptive structure according to another embodiment of the present invention; 6B is a schematic diagram of an inlet end face of an adsorptive structure according to another embodiment of the present invention. FIG. 6C is a schematic diagram of an outlet end face of the adsorptive structure of FIG. 6A. FIG. 6D is a schematic diagram of a cross section taken along line e-e' of FIGS. 6A and 6B. FIG. 6E is a partial enlarged view of the inlet end face of the adsorptive structure to illustrate the shape of each cell. FIG. 6F is a partial enlarged view of the inlet end face of the adsorptive structure to illustrate the shape of each cell. FIG. 6G is a partial enlarged view of the inlet end face of the adsorptive structure to illustrate the shape of each cell. FIG. 6H is a partial enlarged view of the inlet end face of the adsorptive structure to illustrate the shape of each cell. FIG. 6H is a schematic diagram showing the configuration of a gas recovery device according to one embodiment of the present invention. FIG. 6I is a schematic diagram showing the configuration of a gas recovery device according to another embodiment of the present invention. FIG. 6I is a schematic diagram showing the configuration of a gas recovery system according to one embodiment of the present invention.

[0019] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The present invention is not limited to the following embodiments, and it should be understood that modifications and improvements made to the following embodiments based on the ordinary knowledge of those skilled in the art without departing from the spirit of the present invention are also within the scope of the present invention.

[0020] <Adsorption Structure> The adsorption structure according to an embodiment of the present invention can be suitably used to recover a target gas contained in a process gas. The target gas is not particularly limited, but examples thereof include exhaust gases emitted from factories and power plants, and the atmosphere. The exhaust gas is not particularly limited, but examples thereof include combustion exhaust gases generated when burning fossil fuels, coal gas obtained by gasifying coal, and natural gas in thermal power plants and steelworks. The target gas is not particularly limited, but examples thereof include carbon dioxide (CO2), nitrogen oxides (NO x ), sulfur oxides (SO x Among these, the adsorptive structure according to the embodiment of the present invention is particularly useful for recovering carbon dioxide (CO2) contained in combustion exhaust gases and the atmosphere.

[0021] Furthermore, the shape of the adsorptive structure according to the embodiment of the present invention is not particularly limited, and may be a plate, a honeycomb, a pellet, or the like. For example, a plate-shaped or honeycomb-shaped adsorptive structure can be used as a gas adsorption section of a gas recovery device. Furthermore, a plate-shaped or pellet-shaped adsorptive structure can be used as an adsorbent for the gas adsorption section.

[0022] FIG. 1A is a schematic diagram of a cross section of an adsorptive structure according to one embodiment of the present invention. The adsorptive structure in FIG. 1A includes an adsorbent 1 and a protective material 2. The protective material 2 is provided on the surface side of the adsorbent 1 that is exposed to the process gas. Here, in FIG. 1A, the arrows indicate the flow direction of the process gas, and only the right surface side of the adsorbent 1 on the paper is the surface side that is exposed to the process gas. The adsorbent 1 is capable of adsorbing the target gas to be captured contained in the process gas and desorbing the adsorbed target gas to be captured. In addition, the protective material 2 is porous, and the target gas to be captured can pass through due to concentration diffusion. Here, in this specification, "concentration diffusion" refers to the phenomenon of movement from a high concentration to a low concentration.

[0023] In the adsorptive structure of FIG. 1A , the adsorbent 1 adsorbs the target gas, so the concentration of the target gas in the region on the adsorbent 1 side is always low unless the amount of adsorption of the target gas in the adsorbent 1 is saturated. Therefore, a concentration difference in the target gas from the process gas side to the adsorbent 1 side occurs in the protective material 2, and the target gas permeates the protective material 2 by concentration diffusion. Gases other than the target gas contained in the process gas (e.g., oxygen gas) are not adsorbed by the adsorbent 1, so concentration diffusion from the process gas side to the adsorbent 1 side does not occur. Furthermore, in the adsorptive structure of FIG. 1A , when the adsorbent 1 is heated by the process gas (particularly the desorbed gas), the protective material 2 can reduce the temperature difference within the adsorbent 1, thereby mitigating the thermal expansion difference within the adsorbent 1. This results in an adsorptive structure that is less likely to experience partial peeling or cracking even when repeatedly heated.

[0024] Figure 1B is a schematic cross-sectional view of an adsorptive structure according to another embodiment of the present invention. The adsorptive structure of Figure 1B differs from the adsorptive structure of Figure 1A in that it further includes a carrier 3 positioned so as to sandwich the adsorbent 1 between itself and a protective material 2. The carrier 3 supports the adsorbent 1 and may be made of, for example, metal, ceramic, or resin. Note that the flow direction of the process gas in Figure 1B is the same as in Figure 1A. In addition to having the same effect as the adsorptive structure of Figure 1A, the adsorptive structure of Figure 1B, which has the above-described configuration, can suppress the outflow of the adsorbent 1 because it is supported by the carrier 3.

[0025] 1C and 1D are schematic cross-sectional views of an adsorptive structure according to another embodiment of the present invention. The adsorptive structure of FIGS. 1C and 1D differs from the adsorptive structure of FIG. 1A in that the adsorbent 1 is encapsulated in a protective material 2. In this adsorptive structure, the entire surface of the protective material 2 surrounding the adsorbent 1 can be exposed to the process gas. The number of adsorbents 1 encapsulated in the protective material 2 may be single, as in FIG. 1C, or multiple (e.g., two) as in FIG. 1D. The adsorptive structures of FIGS. 1C and 1D, which have the above-described structure, have the same effect as the adsorptive structure of FIG. 1A, and in addition, because the outer periphery of the adsorbent 1 is completely covered by the protective material 2, the outflow of the adsorbent 1 can be suppressed.

[0026] 1E to 1G are schematic cross-sectional views of adsorptive structures according to other embodiments of the present invention. The adsorptive structures of FIGS. 1E to 1G differ from the adsorptive structures of FIGS. 1C and 1D in that the adsorbent 1 is particulate or hollow particulate. In this adsorptive structure, the entire surface of the protective material 2 surrounding the adsorbent 1 can be exposed to the process gas. The particulate adsorbent 1 may be a single particle, as shown in FIG. 1E, or multiple particles, as shown in FIG. 1F. The hollow particulate adsorbent 1 may be a single particle, as shown in FIG. 1G, or multiple particles (not shown). The adsorptive structures of FIGS. 1E to 1G, having the above-described structure, have the same effect as the adsorptive structure of FIG. 1A, but also suppress the outflow of the adsorbent 1 because the outer periphery of the adsorbent 1 is completely covered by the protective material 2.

[0027] Each component of the adsorptive structure will now be described in detail.

[0028] (1. Adsorbent 1) The adsorbent 1 has the function of adsorbing and recovering the target gas contained in the process gas, and easily desorbing the recovered target gas by changing conditions such as temperature. Note that the adsorbent 1 in this specification does not include a catalyst that promotes a chemical reaction of the target gas contained in the process gas. The adsorbent 1 is not particularly limited as long as it is capable of adsorbing the target gas contained in the process gas. For example, the adsorbent 1 can be appropriately selected depending on the type of target gas. Examples of adsorbents 1 effective for adsorbing target gases such as carbon dioxide (CO2) include nitrogen-containing compounds; alkali compounds such as sodium hydroxide and potassium hydroxide; carbonates such as calcium carbonate and potassium carbonate; bicarbonates such as calcium bicarbonate and potassium bicarbonate; porous carriers; and ionic liquids. These can be used alone or in combination of two or more. Specific examples of the nitrogen-containing compound include primary amines such as monoethanolamine and polyvinylamine; secondary amines such as diethanolamine, cyclic amines, and N-(3-aminopropyl)diethanolamine; tertiary amines such as methyldiethylamine and triethanolamine; ethyleneamine compounds such as tetraethylenepentamine; aminosilane coupling agents such as aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N-(2-aminoethyl)-3-aminopropyl-trimethoxysilane, and polyethyleneimine-trimethoxysilane; organic monomers having primary to tertiary amino groups such as ethyleneimine and styrene to which an amino group has been added; organic polymers having primary to tertiary amino groups such as linear polyethyleneimine and branched polyethyleneimine having primary to tertiary amino groups; piperazine compounds such as 1-(2-hydroxyethyl)piperazine; amide compounds such as polyamidoamine; polyvinylamine; and organic / inorganic compounds to which an amino group has been added as a substituent. Among these, methyldiethylamine, monoethanolamine, cyclic amine, diethanolamine, tetraethylenepentamine, ethyleneimine, linear polyethyleneimine, branched polyethyleneimine, and organic / inorganic compounds having an amino group as a substituent are preferred.

[0029] The porous carrier can form mesopores. Specific examples of the porous carrier include metal-organic frameworks (MOFs) such as MOF-74, MOF-200, and MOF-210; activated carbon; nitrogen-doped carbon; mesoporous silica; mesoporous alumina; zeolites; carbon nanotubes; and fluorinated resins such as polyvinylidene fluoride (PVDF). Among these, metal-organic frameworks (MOFs), PVDF, activated carbon, zeolites, mesoporous silica, and mesoporous alumina are preferred. When another adsorbent 1 is supported on the porous carrier, a material different from the porous carrier is used for the other adsorbent 1.

[0030] The shape of the adsorbent 1 is not particularly limited and can be any of the above-mentioned plate-like, particle-like, hollow particle-like, and other known shapes. The size of the adsorbent 1 is also not particularly limited; it can be adjusted appropriately depending on the type of adsorbent structure. For example, when a honeycomb structure described below is used as the protective material 2 as the adsorbent structure, the adsorbent 1 is preferably plate-like or pellet-like. Here, "pellet-like" refers to a shape with a substantially constant thickness, such as a sphere, a cylinder, an elliptical cylinder, or a polygonal prism (e.g., a triangular prism, a square prism, a pentagonal prism, a hexagonal prism, etc.), and its cross section is circular, elliptical, polygonal, or the like. The particle diameter of the pellet-like adsorbent 1 (hereinafter sometimes referred to as "pellet diameter") is not particularly limited, but is, for example, 0.001 to 10 mm, preferably 0.1 to 10 mm, more preferably 0.3 to 10 mm, even more preferably 0.5 to 10 mm, even more preferably 1 to 10 mm, and particularly preferably 2 to 10 mm. The pellet diameter refers to the average value of the minor axis and the major axis. The minor axis and major axis can be measured using a microvideoscope manufactured by Keyence Corp. A typical pellet-shaped adsorbent 1 is spherical or cylindrical with a diameter or length of 0.3 to 10 mm.

[0031] (2. Protective Material 2) The protective material 2 allows the target gas to be captured to pass through due to concentration diffusion. A protective material 2 having such properties can be obtained, for example, by controlling the porosity, thickness, etc. of the protective material 2. The porosity of the protective material 2 is 30 to 80%, and preferably 35 to 75%. By controlling the porosity within such a range, the above-mentioned functions can be obtained. If the porosity of the protective material 2 exceeds 80%, the treatment gas will easily pass through the protective material 2, and the function of protecting the adsorbent 1 will not be obtained. Furthermore, if the porosity of the protective material 2 is less than 30%, it will be difficult for the target gas to be captured to pass through due to concentration diffusion. Here, in this specification, the "porosity of the protective material 2" means the porosity of the protective material 2 measured by mercury intrusion porosimetry in accordance with JIS R1655:2003.

[0032] The protective material 2 preferably has open cells. The open cells allow the target gas to easily pass through by concentration diffusion. Here, the open cells refer to a structure in which pores are continuously connected.

[0033] The thickness of the protective material 2 is preferably 30 to 600 μm, and more preferably 50 to 450 μm. By controlling the thickness within this range, the above-mentioned functions are more easily achieved. If the thickness of the protective material 2 exceeds 600 μm, it becomes difficult to allow the target gas to be captured to pass through by concentration diffusion. Furthermore, if the thickness of the protective material 2 is less than 30 μm, the treatment gas will easily pass through the protective material 2, and the function of protecting the adsorbent 1 will not be sufficiently achieved. Here, in this specification, the "thickness of the protective material 2" refers to the thickness of the protective material 2 covering the adsorbent 1 at the cross section of the adsorptive structure. The thickness of the protective material 2 is measured, for example, by observing the cross section using an SEM (scanning electron microscope) or an optical microscope.

[0034] The protective material 2 has the function of reducing the temperature difference within the adsorbent 1 and mitigating the thermal expansion difference within the adsorbent 1 when the adsorbent 1 is heated by a process gas (particularly, a desorption gas). From the viewpoint of stably ensuring this function, the protective material 2 preferably has a thermal conductivity of 1 to 100 W / m·K, and more preferably 2 to 50 W / m·K. If the thermal conductivity of the protective material 2 exceeds 100 W / m·K, it becomes difficult to reduce the temperature difference within the adsorbent 1. Furthermore, if the thermal conductivity of the protective material 2 is less than 1 W / m·K, the heating efficiency of the adsorbent 1 by the process gas (particularly, a desorption gas) decreases. Here, in this specification, the "thermal conductivity of the protective material 2" refers to the thermal conductivity measured by the laser flash method (JIS R1611:1997).

[0035] The shape of the protective material 2 is not particularly limited as long as it can be provided on the surface side of the adsorbent 1 that is exposed to the process gas. For example, the shape of the protective material 2 can be the various shapes described above (e.g., plate-like, pellet-like), as well as a honeycomb shape. Here, a case where the protective material 2 has a honeycomb shape (is a honeycomb structure) will be described.

[0036] FIG. 2A is a schematic diagram of the inflow end face of an adsorption structure in which the protective material 2 is a honeycomb structure. FIG. 2B is a schematic diagram of the outflow end face of the adsorption structure of FIG. 2A. FIG. 2C is a schematic diagram of a cross section taken along line aa' in FIGS. 2A and 2B. The adsorption structure of FIGS. 2A to 2C includes a honeycomb structure having an outer peripheral wall 10, partition walls 30 disposed inside the outer peripheral wall 10 and extending from the inflow end face 20 to the outflow end face 21 to define first cells 23 and second cells 24, and second-A plugging portions 41 provided in the second cells 24 on the inflow end face 20 side, in which the first cells 23 and the second cells 24 are adjacent to each other via the partition walls 30, and an adsorbent 1 disposed in the second cells 24. In this adsorption structure, the partition walls 30 and the second-A plugging portions 41 function as the protective material 2.

[0037] 2A to 2C having the above-described structure, a process gas flows into the inlet end face 20 of the first cell 23. As the process gas flows through the first cell 23, the target gas to be captured permeates through the partition wall 30 by concentration diffusion, and the target gas to be captured is adsorbed onto the adsorbent 1. The process gas with the target gas to be captured adsorbed flows out from the outlet end face 21 of the second cell 24.

[0038] 2A to 2C show an example in which all of the first cells 23 and the second cells 24 are adjacent to each other via the partition wall 30. However, at least a portion of the first cells 23 and the second cells 24 may be adjacent to each other via the partition wall 30 (i.e., there may be a portion where the first cells 23 and the second cells 24 are not adjacent to each other via the partition wall 30). Schematic diagrams of the inlet end face and the outlet end face of an adsorbent structure of this type are shown in FIGS. 3A and 3B. Note that the cross sections taken along line b-b' in FIGS. 3A and 3B are omitted because they are similar to the cross section taken along line a-a' in FIG. 2A. In the adsorbent structure of FIGS. 3A and 3B, the first cells 23 and the second cells 24 are adjacent to each other via the partition wall 30 in the direction of line b-b', but the first cells 23 and the second cells 24 are not adjacent to each other via the partition wall 30 in the direction perpendicular to line b-b'. An adsorbent structure having such a structure can still achieve the same effects as the adsorbent structure of FIGS. 2A to 2C. The arrangement of the first cells 23 and the second cells 24 is not limited to the forms illustrated in Figures 2A to 2C and Figures 3A to 3B, and may be any arrangement as long as at least a portion of the space between the first cells 23 and the second cells 24 is adjacent to each other with the partition wall 30 interposed therebetween.

[0039] FIG. 4A is a schematic diagram of the inlet end face of another adsorbent structure in which the protective material 2 is a honeycomb structure. FIG. 4B is a schematic diagram of the outlet end face of the adsorbent structure of FIG. 4A. FIG. 4C is a schematic diagram of a cross section taken along line c-c' in FIGS. 4A and 4B. The adsorbent structure shown in FIGS. 4A to 4C differs from the adsorbent structure shown in FIGS. 2A to 2C in that it further includes second-B plugging portions 42 provided in the second cells 24 on the outlet end face 21 side. The provision of the second-B plugging portions 42 prevents the adsorbent 1 from leaking out of the second cells 24. Furthermore, the adsorbent structure shown in FIGS. 4A to 4C has the same process gas flow as the adsorbent structure shown in FIGS. 2A to 2C, and can achieve the same effects as the adsorbent structure shown in FIGS. 2A to 2C. In this adsorbent structure, the second-B plugging portions 42 do not necessarily function as the protective material 2, but may function as such.

[0040] FIG. 5A is a schematic diagram of the inlet end face of another adsorbent structure in which the protective material 2 is a honeycomb structure. FIG. 5B is a schematic diagram of the outlet end face of the adsorbent structure of FIG. 5A. FIG. 5C is a schematic diagram of a cross section taken along line dd' in FIGS. 5A and 5B. The adsorbent structures of FIGS. 5A to 5C differ from the adsorbent structures shown in FIGS. 4A to 4C in that they further include first-A plugging portions 51 provided in the first cells 23 on the inlet end face 20 side. Although not shown, the adsorbent structures shown in FIGS. 2A to 2C may also include first-A plugging portions 51 on the first cells 23 on the inlet end face 20 side. By providing the first-A plugging portions 51, the amount and speed of the process gas flowing into the first cells 23 can be controlled, making it easier for the target gas to permeate through the partition walls 30 by concentration diffusion as the process gas flows through the first cells 23. Therefore, the first-A plugging portions 51 must be porous enough to allow the process gas to pass through.

[0041] FIG. 6A is a schematic diagram of the inlet end face of another adsorbent structure in which the protective material 2 is a honeycomb structure. FIG. 6B is a schematic diagram of the outlet end face of the adsorbent structure of FIG. 6A. FIG. 6C is a schematic diagram of a cross section taken along line e-e' in FIGS. 6A and 6B. The adsorbent structures of FIGS. 6A to 6C differ from the adsorbent structures shown in FIGS. 4A to 4C in that they further include first-B plugging portions 52 provided on the first cells 23 on the outlet end face 21 side. Although not shown, the adsorbent structures shown in FIGS. 2A to 2C may also include first-B plugging portions 52 on the first cells 23 on the outlet end face 21 side. By providing the first-B plugging portions 52, the amount and speed of the process gas flowing into the first cells 23 can be controlled, making it easier for the target gas to permeate through the partition walls 30 by concentration diffusion as the process gas flows through the first cells 23. Therefore, the first-B plugging portions 52 must be porous enough to allow the process gas to pass through.

[0042] Next, the above-mentioned honeycomb structure will be described in more detail. The shape of the honeycomb structure is not particularly limited as long as it has the above-mentioned structure. For example, the outer shape of a cross section perpendicular to the direction in which the flow channels (first cells 23 and second cells 24) of the honeycomb structure extend can be a polygon such as a triangle, a rectangle, a hexagon, or an octagon, or a round shape such as a circle, an ellipse, an oval, an egg, an oval, or a rounded rectangle (a rectangle in which each side and each corner are curved and the radius of curvature of each side is larger than the radius of curvature of each corner). Among these shapes, it is preferable that the outer shape of the cross section of the honeycomb structure is a rectangle (i.e., the shape of the honeycomb structure is a square prism). Note that the end faces (the inlet end face 20 and the outlet end face 21) have the same shape as the cross section.

[0043] In a preferred embodiment, the honeycomb structure has a square pillar shape with sides of the inflow end face 20 and the outflow end face 21 each having a length of 100 to 500 mm (preferably 200 to 400 mm) and a length of 100 to 1000 mm (preferably 300 to 500 mm) in the direction in which the first cells 23 and the second cells 24 extend. A honeycomb structure of this size can ensure a sufficient amount of adsorbent 1 to be filled in the second cells 24, thereby ensuring practicality as an adsorption structure.

[0044] The shape of each cell (first cell 23 and second cell 24) is not particularly limited, but may be polygonal, such as triangular, rectangular, hexagonal, or octagonal, or round, such as circular, elliptical, oval, egg-shaped, or oval, in a cross section perpendicular to the direction in which the flow paths (first cell 23 and second cell 24) of the honeycomb structure extend. Each cell may have a single shape or a combination of two or more shapes. Among these cell shapes, triangular, rectangular, hexagonal, octagonal, or a combination thereof is preferred. Providing cells with such shapes can reduce pressure loss during the flow of the process gas. The shape of each cell in the cross section is the same as the shape of each cell at the end faces (inlet end face 20 and outlet end face 21).

[0045] Examples of combinations of cells having various shapes are shown in Figures 7 to 12. Figures 7 to 12 are partial enlarged views of the inlet end face of an adsorptive structure equipped with cells having various shapes. The embodiment in Figure 7 has two types of hexagonal cells of different sizes. The hexagonal second cells 24 are smaller than the hexagonal first cells 23. The embodiment in Figure 8 has hexagonal cells of the same size. The embodiment in Figure 9 has two types of triangular cells of different sizes. The first cells 23 are composed of triangular cells of two sizes, and the smaller triangular cell is the same size as the second cells 24.

[0046] The embodiment of Fig. 10 has octagonal first cells 23 and octagonal and rectangular second cells 24. The octagonal first cells 23 and the octagonal second cells 24 are the same size. The embodiment of Fig. 11 has three different sizes of rectangular cells. The second cells 24 are smaller than the first cells 23. The embodiment of Fig. 12 has rectangular and hexagonal cells. The first cells 23 are rectangular cells of the same size. The second cells 24 are hexagonal cells. In all of the embodiments of Figs. 7 to 12, the first cells 23 and the second cells 24 are arranged adjacent to each other with a partition wall 30 between them.

[0047] The honeycomb structure may be a honeycomb bonded body having a plurality of honeycomb segments and a bonding layer bonding the outer peripheral surfaces (the outer peripheral surfaces parallel to the extension direction of the honeycomb segments) of the plurality of honeycomb segments together. The use of a honeycomb bonded body makes it possible to increase the total cross-sectional area of ​​the cells, which is important for ensuring the flow rate of the process gas, while suppressing the occurrence of cracks. The bonding layer can be formed using a bonding material. The bonding material is not particularly limited, but a paste-like material obtained by adding a solvent such as water to a ceramic material can be used. The bonding material may contain the same material as the outer peripheral wall 10 and the partition walls 30. In addition to bonding the honeycomb segments together, the bonding material can also be used as an outer peripheral coating material after the honeycomb segments are bonded.

[0048] The thickness of the partition walls 30 can be the same as the thickness of the protective material 2 described above. In this specification, the "thickness of the partition walls 30" refers to the length of a line segment that crosses the partition walls 30 when the line segment connects the centers of gravity of adjacent cells in a cross section of the honeycomb structure that is perpendicular to the direction in which the flow paths (first cells 23 and second cells 24) extend. The thickness of the partition walls 30 refers to the average value of the thicknesses of all the partition walls 30.

[0049] The porosity of the partition walls 30 can be the same as the porosity of the above-described protective material 2. In this specification, the "porosity of the partition walls 30" refers to the porosity of the partition walls 30 measured by mercury porosimetry in accordance with JIS R1655:2003.

[0050] The thermal conductivity of the partition walls 30 can be the same as the thermal conductivity of the above-described protective material 2. In this specification, the "thermal conductivity of the partition walls 30" means the thermal conductivity measured by the laser flash method (JIS R1611:1997).

[0051] The average pore diameter of the partition walls 30 is not particularly limited, but is preferably 10 μm to 300 μm, more preferably 15 μm to 280 μm, and even more preferably 20 μm to 260 μm, from the viewpoint of ensuring the strength of the honeycomb structure, etc. In this specification, the "average pore diameter of the partition walls 30" means the pore diameter of the partition walls 30 at an integrated value of 50% in the pore distribution determined by mercury intrusion porosimetry in accordance with JIS R1655:2003.

[0052] The thickness of the peripheral wall 10 is not particularly limited, but is preferably 0.05 mm to 10 mm, more preferably 0.20 mm to 8 mm, and even more preferably 0.30 mm to 6 mm, from the viewpoint of ensuring the strength of the honeycomb structure. In this specification, the thickness of the peripheral wall 10 refers to the length in the normal direction to the peripheral surface of the honeycomb structure from the boundary between the peripheral wall 10 and the outermost cell or partition wall 30 to the peripheral surface of the honeycomb structure, in a cross section perpendicular to the direction in which the flow paths (first cells 23 and second cells 24) of the honeycomb structure extend.

[0053] The cell density of the honeycomb structure is not particularly limited, but from the viewpoints of ensuring the strength of the honeycomb structure and increasing the amount of adsorbent 1 packed therein, it is preferred that the cell density be 0.05 cells / cm. 2 ~25 cells / cm 2 Preferably, the density is 0.1 cells / cm 2 ~20 cells / cm 2 More preferably, 0.5 cells / cm 2 ~15 cells / cm 2 In this specification, the term "cell density" refers to a value obtained by dividing the number of cells by the area of ​​one end face of the honeycomb structure (the total area of ​​the partition walls 30, the first cells 23, and the second cells 24 excluding the outer peripheral wall 10).

[0054] The material of the outer peripheral wall 10 and the partition walls 30 is not particularly limited, but from the viewpoint of ensuring the strength of the honeycomb structure, it is preferable that the main component be one or more selected from cordierite, mullite, alumina, silicon carbide, Si-bonded silicon carbide, spinel, a silicon carbide-cordierite composite material, lithium aluminum silicate, and aluminum titanate.

[0055] As described above, the 2A plugging portions 41 need to function as the protective material 2, while the 2B plugging portions 42, the 1A plugging portions 51, and the 1B plugging portions 52 do not need to function as the protective material 2. The 2B plugging portions 42 may be dense or porous. Furthermore, the 1A plugging portions 51 and the 1B plugging portions 52 need to be porous enough to allow the flow of a process gas. When forming dense plugging portions, a resin sheet, dense ceramics, glass, or the like may be selected and used, and from the viewpoints of manufacturing cost, productivity, etc., it is preferable to select and use a resin sheet. When forming porous plugging portions, a resin porous sheet, porous ceramics, glass, etc. may be selected and used, and from the viewpoints of manufacturing cost, productivity, etc., it is preferable to select and use a resin porous sheet.

[0056] The shape of the adsorbent 1 placed in the second cells 24 is not particularly limited and may be various shapes. For example, the second cells 24 may be filled with pellet-shaped adsorbent 1, or a coating agent containing the adsorbent 1 may be applied to the partition walls 30 that constitute the second cells 24, and the second cells 24 may be filled with the coating agent.

[0057] <Method for Manufacturing Adsorbent Structure> The method for manufacturing an adsorbent structure according to an embodiment of the present invention is not particularly limited as long as it can produce the above-described structure. For example, the adsorbent structure of FIG. 1A can be manufactured by forming a protective material 2 on a predetermined surface of an adsorbent 1. The method for forming the protective material 2 is not particularly limited, but may involve applying a material that provides the protective material 2 to the predetermined surface of the adsorbent 1 and curing it. Alternatively, the adsorbent structure of FIG. 1A may be manufactured by forming the adsorbent 1 on the predetermined surface of the protective material 2. The method for forming the adsorbent 1 is not particularly limited, but may involve applying a material that provides the adsorbent 1 to the predetermined surface of the protective material 2 and curing it. Alternatively, the adsorbent structure may be formed by forming the adsorbent 1 and the protective material 2 in advance, and then adhering the adsorbent 1 and the protective material 2 together. The method for adhering the adsorbent 1 and the protective material 2 is not particularly limited, but may involve, for example, crimping.

[0058] The adsorptive structure of Fig. 1B can be manufactured by sequentially forming the adsorbent 1 and the protective material 2 on a predetermined surface of the carrier 3. Alternatively, the adsorptive structure of Fig. 1B can be formed by forming the adsorbent 1 and the carrier 3 on a predetermined surface of the protective material 2. Alternatively, the adsorptive structure of Fig. 1B can be manufactured by forming (preparing) the carrier 3, the adsorbent 1, and the protective material 2 in advance, and then sandwiching and adhering the adsorbent 1 between the carrier 3 and the protective material 2. The methods for forming and adhering each material may be the same as those described above.

[0059] The bonded structures of Figures 1C and 1E can be produced by preparing an adsorbent 1 of a predetermined shape and forming a protective material 2 over its entire surface. The method for forming the protective material 2 can be the same as described above. The bonded structures of Figures 1D and 1G can be produced by preparing an adsorbent 1 of a predetermined shape and forming a protective material 2 over its predetermined surface. Alternatively, they can be produced by preparing a protective material 2 divided into two pieces, forming an adsorbent 1 inside one piece, and then bonding the two pieces together. The bonded structure of Figure 1F can be produced by preparing a protective material 2 with a filling port for filling the adsorbent 1 inside, filling the adsorbent 1 through the filling port, and then filling the filling port with the protective material 2.

[0060] 2A to 2C have a peripheral wall 10, partition walls 30 disposed inside the peripheral wall 10 and defining first cells 23 and second cells 24 extending from the inflow end face 20 to the outflow end face 21, and secondA plugging portions 41 provided in the second cells 24 on the inflow end face 20 side, and can be manufactured by preparing a honeycomb structure in which the first cells 23 and the second cells 24 are adjacent to each other via the partition walls 30, and filling the second cells 24 with the adsorbent 1. Furthermore, when the secondB plugging portions 42, the firstA plugging portions 51, or the firstB plugging portions 52 are provided at predetermined positions of the honeycomb structure, they may be formed at an appropriate stage.

[0061] The method for manufacturing a honeycomb structure is not particularly limited and can be carried out according to methods known in the art. For example, a honeycomb structure can be manufactured as follows. First, a clay containing ceramic powder is extruded into a desired shape to produce a honeycomb formed body. By selecting an appropriate die and jig, the shape and density of each cell, the shape and thickness of the partition walls 30 and the peripheral wall 10, etc. can be controlled. The ceramic powder can be the aforementioned ceramic powder or a raw material powder (e.g., a cordierite raw material) that will become the aforementioned ceramic after firing. The cordierite raw material is a raw material that will become cordierite upon firing. The cordierite raw material preferably has a chemical composition of 30 to 45 mass% alumina (Al2O3) (including aluminum hydroxide converted to alumina), 11 to 17 mass% magnesia (MgO), and 42 to 57 mass% silica (SiO2). The clay can also contain a binder, a pore-forming agent, a dispersant, water, an organic solvent, etc. The porosity and average pore diameter of the partition walls 30 can be controlled by appropriately selecting the types and amounts of the ceramic powder, binder, pore-forming agent, and dispersant used. Next, the honeycomb formed body obtained above is dried and fired to obtain a honeycomb structure. The drying method is not particularly limited, and conventionally known drying methods such as hot air drying, microwave drying, dielectric drying, reduced pressure drying, vacuum drying, and freeze drying can be used. Among these, a drying method that combines hot air drying with microwave drying or dielectric drying is preferred because it can dry the entire honeycomb formed body quickly and uniformly.

[0062] The method for forming the 2A plugging portions 41 in the second cells 24 on the inlet end face 20 side is not particularly limited, and can be performed according to a conventional method. For example, when the 2A plugging portions 41 are made of a resin sheet, the 2A plugging portions 41 can be formed by attaching the resin sheet to the inlet end face 20 of the second cells 24. When the 2A plugging portions 41 are made of ceramics, glass, or the like, first, a thin film having openings corresponding to the second cells 24 on the inlet end face 20 of the honeycomb structure where the 2A plugging portions 41 are to be formed is attached. Next, the inlet end face 20 of the honeycomb structure is immersed in a slurry plugging material (ceramics, glass, or the like), and the plugging material is allowed to penetrate into the second cells 24 of the honeycomb structure that are not plugged with the thin film, thereby forming the 2A plugging portions 41. In addition, when forming the 2B plugging portions 42, the 1A plugging portions 51 or the 1B plugging portions 52, the method may be similar to that described above.

[0063] The method for filling the second cell 24 with the adsorbent 1 is not particularly limited, and may be carried out in accordance with a conventional method.

[0064] <Gas Recovery Apparatus> A gas recovery apparatus according to an embodiment of the present invention includes the above-described adsorbent structure. This gas recovery apparatus can be used to recover and release a target gas contained in a treatment gas. Because the above-described adsorbent structure is resistant to partial peeling or cracking even when repeatedly heated, this gas recovery apparatus can prevent the adsorbent from leaking to the outside.

[0065] Fig. 13 is a schematic diagram showing the configuration of a gas recovery apparatus according to one embodiment of the present invention. As shown in Fig. 13, the gas recovery apparatus 1000 includes a reactor 1100, a gas supply pipe 1200 capable of supplying a process gas or a purge gas to an inlet 1110 of the reactor 1100, and a gas exhaust pipe 1300 capable of exhausting the process gas or the purge gas from an outlet 1120 of the reactor 1100. Various reactors having the above-described adsorptive structure as an adsorption section can be used as the reactor 1100. Alternatively, when the adsorptive structure has a honeycomb shape, the adsorptive structure can be used as the reactor 1100.

[0066] The gas supply pipe 1200 has a gas supply branch pipe branched into two. This gas supply branch pipe can be a first gas supply branch pipe 1210 capable of supplying a process gas, and a second gas supply branch pipe 1220 capable of supplying a purge gas. The gas exhaust pipe 1300 has a gas exhaust branch pipe branched into two. This gas exhaust branch pipe can be a first gas exhaust branch pipe 1310 capable of exhausting a process gas, and a second gas exhaust branch pipe 1320 capable of exhausting a purge gas. The gas recovery apparatus 1000 further includes a supply gas switching valve 1400 capable of blocking the first gas supply branch pipe 1210 or the second gas supply branch pipe 1220, and an exhaust gas switching valve 1500 capable of blocking the first gas exhaust branch pipe 1310 or the second gas exhaust branch pipe 1320.

[0067] In the gas recovery device 1000 having the above-described structure, when recovering the target gas contained in the treatment gas, the supply gas switching valve 1400 is switched to block the second gas supply branch pipe 1220 and open the first gas supply branch pipe 1210, and the exhaust gas switching valve 1500 is switched to block the second gas exhaust branch pipe 1320 and open the first gas exhaust branch pipe 1310. Next, the treatment gas containing the target gas to be captured is supplied from the first gas supply branch pipe 1210 through the gas supply pipe 1200 to the inlet 1110 of the reactor 1100. The target gas to be captured is recovered from the treatment gas supplied to the reactor 1100 and discharged from the outlet 1120. The discharged treatment gas is discharged from the first gas exhaust branch pipe 1310 via the gas exhaust pipe 1300.

[0068] Next, when desorbing the target gas to be captured recovered in the reactor 1100, the supply gas switching valve 1400 is switched to open the second gas supply branch pipe 1220 and block the first gas supply branch pipe 1210, and the exhaust gas switching valve 1500 is switched to open the second gas exhaust branch pipe 1320 and block the first gas exhaust branch pipe 1310. Next, purge gas is supplied from the second gas supply branch pipe 1220 via the gas supply pipe 1200 to the inlet 1110 of the reactor 1100. The purge gas supplied to the reactor 1100 is discharged from the outlet 1120 together with the target gas to be captured by the adsorbent 1 of the reactor 1100. The purge gas containing the target gas to be captured is discharged from the second gas exhaust branch pipe 1320 via the gas exhaust pipe 1300. Here, in this specification, the term "purge gas" refers to a gas that can desorb the target gas captured by the adsorbent 1 of the reactor 1100 and be discharged from the reactor 1100. The purge gas may be selected appropriately depending on the type of target gas. For example, when the target gas is carbon dioxide, water vapor or the like can be used. The water vapor is preferably at a high temperature of 100°C or higher (for example, 120°C).

[0069] Furthermore, in order to heat the purge gas to a predetermined temperature, the gas recovery system 1000 may further include a heating mechanism capable of heating the reactor 1100. With this configuration, the purge gas at room temperature can be supplied from the second gas supply branch pipe 1220 and heated to a predetermined temperature in the reactor 1100. Therefore, it is not necessary to preheat the purge gas to be supplied to the gas recovery system 1000.

[0070] Fig. 14 is a schematic diagram showing the configuration of a gas recovery apparatus according to another embodiment of the present invention. As shown in Fig. 14, a gas recovery apparatus 2000 has the same basic structure as the gas recovery apparatus 1000 of Fig. 13. That is, the gas recovery apparatus 2000 includes a reactor 1100, a gas supply pipe 1200 capable of supplying a treatment gas or a purge gas to an inlet 1110 of the reactor 1100, and a gas exhaust pipe 1300 capable of exhausting the treatment gas or the purge gas from an outlet 1120 of the reactor 1100. Therefore, the gas recovery apparatus 2000 can also suppress the outflow of the adsorbent to the outside.

[0071] The gas supply pipe 1200 has two independent gas supply pipes. The two independent gas supply pipes are a first gas supply pipe 2100 capable of supplying a process gas and a second gas supply pipe 2200 capable of supplying a purge gas. The gas exhaust pipe 1300 has two independent gas exhaust pipes. The two independent gas exhaust pipes are a first gas exhaust pipe 2300 capable of exhausting a process gas and a second gas exhaust pipe 2400 capable of exhausting a purge gas. The reactor 1100 can be disposed between the first gas supply pipe 2100 and the first gas exhaust pipe 2300 or between the second gas supply pipe 2200 and the second gas exhaust pipe 2400. The gas recovery device 2000 further includes a transfer mechanism (not shown) capable of transferring the reactor 1100 between the first gas supply pipe 2100 and the first gas exhaust pipe 2300 or between the second gas supply pipe 2200 and the second gas exhaust pipe 2400. The transfer mechanism is not particularly limited, and a known transfer mechanism (for example, a motor-driven transfer mechanism) can be used.

[0072] In the gas recovery device 2000 having the above structure, when recovering a target gas contained in a process gas, the reactor 1100 is disposed between the first gas supply pipe 2100 and the first gas exhaust pipe 2300 by a transfer mechanism. Next, a process gas containing the target gas is supplied from the first gas supply pipe 2100 to the inlet 1110 of the reactor 1100. The target gas is recovered from the process gas supplied to the reactor 1100 and discharged from the outlet 1120. The discharged process gas is discharged from the first gas exhaust pipe 2300. Next, when desorbing the target gas recovered in the reactor 1100, the reactor 1100 is disposed between the second gas supply pipe 2200 and the second gas exhaust pipe 2400 by a transfer mechanism. Next, a purge gas is supplied from the second gas supply pipe 2200 to the inlet 1110 of the reactor 1100. The purge gas supplied to the reactor 1100 is discharged from the outlet 1120 together with the target gas to be captured that has been captured by the adsorbent 1 of the reactor 1100. The purge gas containing the target gas to be captured is discharged from the second gas discharge pipe 2400. The same purge gas as described above can be used.

[0073] Furthermore, in order to heat the purge gas to a predetermined temperature, the gas recovery device 2000 may further include a heating mechanism capable of heating the reactor 1100 disposed between the second gas supply pipe 2200 and the second gas exhaust pipe 2400. With this configuration, the purge gas at room temperature can be supplied from the second gas supply pipe 2200 and heated to a predetermined temperature in the reactor 1100. Therefore, there is no need to preheat the purge gas to be supplied to the gas recovery device 2000.

[0074] FIG. 15 is a schematic diagram showing the configuration of a gas recovery apparatus according to another embodiment of the present invention. As shown in FIG. 15 , the gas recovery apparatus 4000 includes a can body 4100 and a plurality of reactors 1100 disposed within the can body 4100. The main flow path (a flow path from one end to the other) of the can body 4100 allows treatment gas to flow through. The reactor 1100 is composed of a honeycomb-shaped adsorbent structure (hereinafter referred to as a "honeycomb adsorbent structure"). The plurality of honeycomb adsorbent structures are stacked within the can body 4100 with their outer peripheral walls 10 facing each other. The outer peripheral walls 10 of the plurality of honeycomb adsorbent structures may be in contact with each other, or a holding member 4200 may be provided between the outer peripheral walls 10. The stacked plurality of honeycomb adsorbent structures are arranged in two separate regions within the can body 4100. A purge gas supply section 4300 is provided between the two regions on the side of the can body 4100, and purge gas discharge sections 4400 are provided upstream and downstream of the two regions. A supply valve 4350 is provided in the purge gas supply section 4300, and a discharge valve 4450 is provided in the purge gas discharge section 4400. A switching valve 4500 is also provided inside the can body 4100 to switch the gas flowing through the honeycomb adsorptive structure between treatment gas and purge gas.

[0075] In the gas recovery device 4000 having the above-described structure, when recovering the target gas contained in the treatment gas, the switching valve 4500 is opened, and the supply valve 4350 and the exhaust valve 4450 are closed, so that the treatment gas flows through the main flow path of the can body 4100. In this manner, the treatment gas containing the target gas is supplied to the honeycomb adsorptive structure. The target gas is recovered from the treatment gas supplied to the honeycomb adsorptive structure and discharged from the can body 4100. Next, when desorbing the target gas recovered in the honeycomb adsorptive structure, the switching valve 4500 is closed, and the supply valve 4350 and the exhaust valve 4450 are opened to supply purge gas from the purge gas supply unit 4300. The purge gas supplied between the two regions flows into the honeycomb adsorptive structure and is discharged from the purge gas exhaust unit 4400 together with the target gas captured by the honeycomb adsorptive structure. The supply of purge gas may be performed while reducing the pressure inside the can body 4100 using an internal pump. The purge gas can be the same as that described above.

[0076] <Gas Recovery System> A gas recovery system according to an embodiment of the present invention can be suitably used to recover and release a target gas contained in a process gas. FIG. 16 is a schematic diagram showing the configuration of a gas recovery system according to an embodiment of the present invention. As shown in FIG. 16, a gas recovery system 3000 includes a gas recovery device 3100, a gas release device 3200, and a transfer device 3300. The gas recovery device 3100 includes a detachable unit 3110 that can be attached to and detached from the reactor 1100, a gas supply pipe 1200 that can supply a process gas to the inlet 1110 of the reactor 1100, and a gas exhaust pipe 1300 that can exhaust the process gas from the outlet 1120 of the reactor 1100. The gas release device 3200 includes a detachable part 3210 that allows the reactor 1100 to be detached, a gas supply pipe 1200 that can supply a purge gas to the inlet 1110 of the reactor 1100, and a gas discharge pipe 1300 that can discharge the purge gas from the outlet 1120 of the reactor 1100. The transfer device 3300 is capable of transferring the reactor 1100, from which the gas to be captured has been recovered by the gas recovery device 3100, to the gas release device 3200, and of transferring the reactor 1100, from which the gas to be captured has been released by the gas release device 3200, to the gas recovery device 3100.

[0077] In the gas recovery system 3000 having the above structure, when recovering the target gas contained in the treatment gas, the reactor 1100 is placed in the attachment / detachment section 3110 of the gas recovery device 3100 by the transfer device 3300. Next, the treatment gas containing the target gas is supplied from the gas supply pipe 1200 of the gas recovery device 3100 to the inlet 1110 of the reactor 1100. The target gas is recovered from the treatment gas supplied to the reactor 1100 and discharged from the outlet 1120. The discharged treatment gas is discharged from the gas discharge pipe 1300. Next, when desorbing the target gas recovered in the reactor 1100, the reactor 1100 placed in the gas recovery device 3100 is moved to the attachment / detachment section 3210 of the gas release device 3200 by the transfer device 3300. Next, a purge gas is supplied from the gas supply pipe 1200 of the gas release device 3200 to the inlet 1110 of the reactor 1100. The purge gas supplied to the reactor 1100 is discharged from the outlet 1120 together with the target gas to be captured that has been captured by the adsorbent 1 of the reactor 1100. The purge gas containing the target gas to be captured is discharged from the gas discharge pipe 1300. The same purge gas as described above can be used.

[0078] Furthermore, in order to heat the purge gas to a predetermined temperature, the gas discharge device 3200 may further include a heating mechanism capable of heating the reactor 1100. With such a configuration, the purge gas can be supplied at room temperature from the gas supply pipe 1200 and heated to a predetermined temperature in the reactor 1100. Therefore, it is not necessary to preheat the purge gas to be supplied to the gas discharge device 3200.

[0079] The transfer device 3300 is not particularly limited, but may include a vehicle. With this configuration, even if the gas recovery device 3100 and the gas release device 3200 are located at distant locations, the reactor 1100 can be transported efficiently.

[0080] DESCRIPTION OF SYMBOLS 1 adsorbent 2 protective material 3 carrier 10 outer peripheral wall 20 inlet end surface 21 outlet end surface 23 first cell 24 second cell 30 partition wall 41 second A plugging portion 42 second B plugging portion 51 first A plugging portion 52 first B plugging portion 1000, 2000, 4000 gas recovery device 1100 reactor 1110 inlet 1120 outlet 1200 gas supply pipe 1210 first gas supply branch pipe 1220 second gas supply branch pipe 1300 gas exhaust pipe 1310 first gas exhaust branch pipe 1320 second gas exhaust branch pipe 1400 supply gas switching valve 1500 exhaust gas switching valve 2100 first gas supply pipe 2200 second gas supply pipe 2300 first gas exhaust pipe 2400 Second gas exhaust pipe 3000 Gas recovery system 3100 Gas recovery device 3110 Detachable unit 3200 Gas release device 3210 Detachable unit 3300 Transfer device 4100 Can body 4200 Holding member 4300 Purge gas supply unit 4350 Supply valve 4400 Purge gas exhaust unit 4450 Exhaust valve 4500 Switching valve

Claims

1. An adsorptive structure comprising: an adsorbent capable of adsorbing a target gas contained in a process gas and desorbing the adsorbed target gas; and a porous protective material provided on the surface side of the adsorbent exposed to the process gas, wherein the protective material has a porosity of 30 to 80% and is permeable to the target gas by concentration diffusion.

2. The adsorptive structure according to claim 1, further comprising a carrier positioned so as to sandwich said adsorbent between said carrier and said protective material.

3. The adsorptive structure of claim 1, wherein said adsorbent is encapsulated in said protective material.

4. The adsorptive structure according to any one of claims 1 to 3, wherein the protective material has open cells.

5. The adsorptive structure according to any one of claims 1 to 3, wherein said adsorptive structure is in the form of a plate or a honeycomb.

6. The adsorptive structure of any one of claims 1 to 3, wherein said adsorptive structure is in pellet form.

7. The adsorptive structure according to any one of claims 1 to 3, wherein the target gas to be captured is an acid gas.

8. The adsorptive structure according to any one of claims 1 to 3, wherein the gas to be captured is carbon dioxide.

9. A gas recovery device for recovering and releasing a target gas contained in a treatment gas, the gas recovery device comprising the adsorptive structure according to any one of claims 1 to 3.

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