Reactor and gas recovery device

Abstract

This reactor comprises: a plurality of honeycomb structures which each have an outer peripheral wall 11 and a partition wall 15 disposed inside the outer peripheral wall 11 to partition and form a plurality of cells 14 extending from an inflow end surface 12 to an outflow end surface 13, and in which the outer peripheral walls 11 and the partition walls 15 contain an adsorbent capable of adsorbing and desorbing greenhouse gases; an elastic sheet 20 which has a plurality of through holes 21 and which, by having the plurality of honeycomb structures 10 inserted in the plurality of through holes 21, holds the surfaces of the outer peripheral walls 11 parallel to the direction in which the cells 14 extend such that the surfaces face each other with a prescribed interval therebetween; and a cylindrical member 30 that houses the plurality of honeycomb structures 10 and the elastic sheet 20.

Description

Reactor and gas recovery device

[0001] The present invention relates to a reactor and a gas recovery device.

[0002] To realize a decarbonized society, there is a growing need for technologies that capture and utilize greenhouse gases (e.g., carbon dioxide) from the atmosphere and exhaust gases. A typical conventional carbon dioxide (CO2) capture technology is Direct Air Capture (DAC), which adsorbs CO2 from the atmosphere. There are several types of DAC, including liquid absorption, membrane separation, and solid adsorption. Among these, the use of a honeycomb structure containing a CO2 adsorbent (absorbent) has been considered for the solid adsorption method.

[0003] For example, Patent Document 1 (Patent Document 1) describes a honeycomb structure having a plurality of partition walls extending axially from the inlet end to the outlet end, thereby forming a plurality of flow channels. The honeycomb structure comprises a mixture of an inorganic powder component and an organic binder, and an amine polymer having a functional structural unit group capable of absorbing CO2 is dispersed in the inorganic powder component of the partition walls. The honeycomb structure can adsorb CO2 by passing a CO2-containing process gas through the cells. Furthermore, the CO2 adsorbed in the honeycomb structure can be desorbed by passing a purge gas (desorption gas) such as water vapor through the cells.

[0004] Special table 2015-508018 publication

[0005] Honeycomb structures are mainly manufactured by extrusion molding, but there are limits to the size that can be manufactured due to factors such as their own weight. On the other hand, because the CO2 concentration in the processing gas (e.g., air) is low, it is desirable to use a large honeycomb structure in order to efficiently capture CO2 in the reactor. For this reason, it is necessary to arrange multiple honeycomb structures side by side in the reactor. In this case, the honeycomb structures are bonded together with an adhesive or the like to prevent misalignment of the honeycomb structures.

[0006] The CO2 adsorbed in the honeycomb structure described in Patent Document 1 is desorbed by passing a purge gas such as water vapor through the cells, as described above. During this process, the adsorbent (amine polymer) absorbs water and expands. Therefore, when multiple honeycomb structures are arranged side by side in a reactor, the expansion of the honeycomb structures can cause damage. In particular, the honeycomb structure described in Patent Document 1 is manufactured without firing, resulting in low strength and making the honeycomb structure more susceptible to damage. Furthermore, the honeycomb structure described in Patent Document 1 expands during CO2 desorption and contracts during CO2 adsorption, which can easily cause separation between bonded honeycomb structures and lead to misalignment of the honeycomb structures within the reactor. While the above description has been given using the example of CO2 as the gas to be adsorbed, similar problems can occur when adsorbing and desorbing other greenhouse gases.

[0007] The present invention has been made to solve the above-mentioned problems, and aims to provide a reactor and a gas recovery device that can suppress damage due to expansion of the honeycomb structure and displacement due to expansion and contraction of the honeycomb structure.

[0008] As a result of extensive research into a reactor in which a plurality of honeycomb structures are arranged inside a cylindrical member, the inventors have found that the above-mentioned problems can be solved by inserting a plurality of honeycomb structures into a plurality of through-holes formed in an elastic sheet and holding them so that they face each other at a predetermined interval, thereby completing the present invention. That is, the present invention is exemplified as follows.

[0009] <1> A reactor comprising: a plurality of honeycomb structures having an outer peripheral wall; and partition walls disposed inside the outer peripheral wall and defining a plurality of cells extending from an inflow end face to an outflow end face, the outer peripheral wall and the partition walls containing an adsorbent capable of adsorbing and desorbing greenhouse gases; an elastic sheet having a plurality of through holes and configured to hold surfaces of the outer peripheral wall parallel to an extension direction of the cells so as to face each other at a predetermined interval by inserting the plurality of honeycomb structures into the plurality of through holes; and a cylindrical member that accommodates the plurality of honeycomb structures and the elastic sheet.

[0010] <2> The reactor according to <1>, wherein the elastic sheet is disposed at at least two locations on the inflow end face side and the outflow end face side of the honeycomb structure.

[0011] <3> The reactor according to <2>, further comprising frame-shaped lid members disposed on both end surfaces of the cylindrical member, wherein the elastic sheet is fixed by sandwiching ends of the elastic sheet between the cylindrical member and the frame-shaped lid members.

[0012] <4> The reactor according to any one of <1> to <3>, wherein the through-holes of the elastic sheet have the same shape as a cross section of the honeycomb structure perpendicular to the direction in which the cells extend.

[0013] <5> The reactor according to <4>, wherein the diameter of the through-holes of the elastic sheet is 5 to 15% smaller than the outer diameter of a cross section of the honeycomb structure in a state of contraction that is perpendicular to the direction in which the cells extend.

[0014] <6> The reactor according to any one of <1> to <5>, wherein the elastic sheet has a thickness of 0.3 to 10 mm.

[0015] <7> The reactor according to any one of <1> to <6>, wherein the honeycomb structure has an expansion rate of 3 to 20% of the outer diameter when expanded relative to the outer diameter when contracted in a cross section perpendicular to the extension direction of the cells.

[0016] <8> The reactor according to any one of <1> to <7>, wherein the elastic sheet is a rubber sheet.

[0017] <9> The reactor according to any one of <1> to <8>, wherein the adsorbent is an amine compound.

[0018] <10> The reactor according to any one of <1> to <9>, wherein the greenhouse gas is carbon dioxide.

[0019] <11> A gas recovery device comprising the reactor according to any one of <1> to <10>.

[0020] According to the present invention, it is possible to provide a reactor and a gas recovery device that can suppress breakage due to expansion of a honeycomb structure and displacement due to expansion and contraction of the honeycomb structure.

[0021] FIG. 1B is a schematic diagram of a cross section parallel to the flow direction of the process gas of a reactor according to an embodiment of the present invention. FIG. 1C is a schematic diagram of a cross section taken along line a-a' in FIG. 1A. FIG. 1D is a schematic diagram of an end face perpendicular to the cell extension direction of a honeycomb structure used in a reactor according to an embodiment of the present invention. FIG. 2E is a schematic diagram of a cross section taken along line bb' in FIG. 2A. FIG. 2F is a perspective view of an elastic sheet used in a reactor according to an embodiment of the present invention. FIG. 2G is a schematic diagram for explaining the state inside a reactor during adsorption and desorption of greenhouse gases. FIG. 2H is a schematic diagram of a cross section parallel to the flow direction of the process gas of another reactor according to an embodiment of the present invention. FIG. 5A is a schematic diagram of one end face of the reactor of FIG.

[0022] The reactor of the present invention includes a plurality of honeycomb structures having an outer peripheral wall and partition walls disposed inside the outer peripheral wall and defining a plurality of cells extending from the inlet end face to the outlet end face, the outer peripheral wall and the partition walls containing an adsorbent capable of adsorbing and desorbing greenhouse gases; an elastic sheet having a plurality of through-holes for inserting the plurality of honeycomb structures into the plurality of through-holes to hold the surfaces of the outer peripheral wall parallel to the cell extension direction so as to face each other at a predetermined distance; and a tubular member for accommodating the plurality of honeycomb structures and the elastic sheet. The reactor of the present invention has the above-described configuration, whereby the plurality of honeycomb structures can be held in a predetermined position by the elastic sheet, and the expansion of the honeycomb structures can be absorbed by the elastic sheet, thereby preventing the honeycomb structures from contacting each other. This makes it possible to prevent damage due to the expansion of the honeycomb structures and displacement due to the expansion and contraction of the honeycomb structures.

[0023] 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.

[0024] (1. Reactor) The reactor according to an embodiment of the present invention can be suitably used to recover greenhouse gases contained in a process gas. Examples of process gases include, but are not limited to, exhaust gases emitted from factories and power plants, and the atmosphere. Examples of exhaust gases include, but are not limited to, combustion exhaust gases generated when burning fossil fuels, coal gasification gas obtained by gasifying coal, and natural gas in thermal power plants and steelworks. Examples of greenhouse gases include, but are not limited to, carbon dioxide (CO), methane (CH), nitrogen oxides such as nitrous oxide (NO), hydrofluorocarbons, perfluorocarbons, sulfur hexafluoride (SF), and the like. Among these, the reactor according to an embodiment of the present invention is particularly useful for recovering carbon dioxide (CO) contained in combustion exhaust gases and the atmosphere.

[0025] FIG. 1A is a schematic diagram of a cross section parallel to the flow direction of the process gas of a reactor according to an embodiment of the present invention. FIG. 1B is a schematic diagram of a cross section taken along line aa' in FIG. 1A (a cross section perpendicular to the flow direction of the process gas). FIG. 2A is a schematic diagram of an end face perpendicular to the cell extension direction of a honeycomb structure used in a reactor according to an embodiment of the present invention. FIG. 2B is a schematic diagram of a cross section taken along line bb' in FIG. 2A (a cross section parallel to the cell extension direction). FIG. 3 is a perspective view of an elastic sheet used in a reactor according to an embodiment of the present invention.

[0026] As shown in FIGS. 1A and 1B , the reactor includes a plurality of honeycomb structures 10, an elastic sheet 20, and a tubular member 30. It should be noted that detailed structure of the honeycomb structure 10 is omitted in FIGS. 1A and 1B . Each honeycomb structure 10 disposed in the reactor includes an outer peripheral wall 11 and partition walls 15 disposed inside the outer peripheral wall 11 and defining a plurality of cells 14 extending from an inlet end face 12 to an outlet end face 13, as shown in FIGS. 2A and 2B . The outer peripheral wall 11 and the partition walls 15 contain an adsorbent capable of adsorbing and desorbing greenhouse gases. As shown in FIG. 3 , the elastic sheet 20 has a plurality of through-holes 21. As shown in FIGS. 1A and 1B , the elastic sheet 20 holds the surfaces of the outer peripheral walls 11, which are parallel to the extension direction of the cells 14, facing each other at a predetermined interval by inserting the plurality of honeycomb structures 10 into the through-holes 21. The cylindrical member 30 accommodates a plurality of honeycomb structures 10 and elastic sheets 20 .

[0027] FIG. 4 is a schematic diagram (schematic diagram of a cross section perpendicular to the flow direction of the treatment gas) for explaining the state inside the reactor during adsorption and desorption of greenhouse gases. As shown in FIG. 4, during adsorption of greenhouse gases, each honeycomb structure 10 is in a contracted state. At this time, each honeycomb structure 10 is held by the elastic sheet 20, so that displacement within the reactor can be suppressed. On the other hand, during desorption of greenhouse gases, each honeycomb structure 10 is in an expanded state due to water absorption. At this time, the expansion of each honeycomb structure 10 is absorbed by the elastic sheet 20, and damage due to contact between adjacent honeycomb structures 10 is suppressed.

[0028] The components of the reactor will now be described in detail.

[0029] (1-1) Honeycomb Structure 10 As described above, the honeycomb structure 10 has an outer peripheral wall 11 and partition walls 15 disposed inside the outer peripheral wall 11 to define a plurality of cells 14 extending from an inlet end face 12 to an outlet end face 13. The plurality of cells 14 are arranged parallel to one another. The honeycomb structure 10 is a flow-through type in which both ends (the inlet end face 12 and the outlet end face 13) of each cell 14 are open. When a process gas (e.g., air) containing a greenhouse gas flows in through the inlet end face 12 where the inlets of the plurality of cells 14 are located, the greenhouse gas is adsorbed as the gas passes through the plurality of cells 14, and the process gas with a reduced greenhouse gas concentration flows out from the outlet end face 13 where the outlets of the plurality of cells 14 are located.

[0030] The end face shape of the honeycomb structure 10 is not particularly limited, and may be, for example, a round shape such as a circle, an ellipse, a racetrack shape, or an oval shape, a polygonal shape such as a triangle or a square, or other irregular shape. However, a square shape is preferable in consideration of ease of arrangement in a reactor. The outer shape of the honeycomb structure 10 can typically be a columnar shape. Note that the honeycomb structure 10 shown in Figures 2A and 2B has a square end face shape and is an example of a square columnar shape as a whole.

[0031] The length in the direction in which the cells 14 of the honeycomb structure 10 extend (the length from the inlet end face 12 to the outlet end face 13) is not particularly limited and may be set appropriately depending on the application and required performance. However, while a longer length in the direction in which the cells 14 of the honeycomb structure 10 extend can increase the amount of greenhouse gases adsorbed, if the length is too long, pressure loss increases. For this reason, the length is preferably 20 to 350 mm, more preferably 20 to 300 mm, and even more preferably 20 to 250 mm.

[0032] The diameter of each end face of the honeycomb structure 10 is not particularly limited and may be set appropriately depending on the application and required performance. However, while a larger diameter of each end face of the honeycomb structure 10 can increase the amount of greenhouse gas adsorption, if the diameter is too large it increases the difficulty of manufacturing, so the diameter is preferably 10 to 300 mm, more preferably 15 to 250 mm, and even more preferably 20 to 200 mm. Here, the diameter of each end face of the honeycomb structure 10 in this specification means the diameter if the honeycomb structure is circular, and means the circle-equivalent diameter if the honeycomb structure is other than circular.

[0033] In the cross section of the honeycomb structure 10 perpendicular to the extension direction of the cells 14, the expansion rate of the outer diameter during expansion (when desorbing greenhouse gases) relative to the outer diameter during contraction (when adsorbing greenhouse gases) is not particularly limited, but is preferably 3 to 20%, more preferably 3 to 18%, and even more preferably 3 to 15%. A honeycomb structure 10 having such an expansion rate can easily achieve the effect of suppressing breakage due to expansion of the honeycomb structure 10 and displacement due to expansion and contraction of the honeycomb structure 10. Here, the outer diameter of the honeycomb structure 10 in this specification refers to the diameter if the honeycomb structure 10 has a circular shape, and refers to the circle-equivalent diameter if the honeycomb structure 10 has a shape other than a circular shape. Regarding the length in the extension direction of the cells 14 of the honeycomb structure 10, the expansion rate of the length during expansion (when desorbing greenhouse gases) relative to the length during contraction (when adsorbing greenhouse gases) is preferably 3 to 20%, more preferably 4 to 18%, and even more preferably 5 to 15%.

[0034] The outer peripheral wall 11 and partition walls 15 constituting the honeycomb structure 10 contain an adsorbent (hereinafter abbreviated as "adsorbent") capable of adsorbing and desorbing greenhouse gases. By incorporating the adsorbent into the outer peripheral wall 11 and partition walls 15, it becomes possible to adsorb greenhouse gases contained in the process gas. Furthermore, compared to conventional honeycomb structures in which the surfaces of the outer peripheral wall 11 and partition walls 15 are coated with an adsorbent, the honeycomb structure 10 can be manufactured without undergoing a firing process at a high heating temperature, thereby reducing greenhouse gases generated during manufacturing. Furthermore, the amount of adsorbent carried can be increased, thereby increasing the amount of greenhouse gas adsorption.

[0035] The adsorbent is not particularly limited as long as it is capable of adsorbing and desorbing greenhouse gases, but an amine compound is preferred. Specifically, the amine compound is preferably a solid organic compound having an amino group (one or more selected from -NH, -NHR, and -NRR' (R and R' represent organic groups)). Although the present invention is not intended to be limited by theory, a solid organic compound having an amino group can adsorb carbon dioxide by reacting with carbon dioxide to produce a carbamate or bicarbonate. Furthermore, a solid organic compound having an amino group can be reacted with an organic binder by using an organic binder having a specific functional group described below.

[0036] From the viewpoint of water resistance, it is desirable that the solid organic compound having an amino group be water-insoluble. Furthermore, the solid organic compound having an amino group may have any of -NH2, -NHR, and -NRR' (R and R' represent organic groups), or may have a combination of two or more of these. Among amino groups, it is particularly preferable that the solid organic compound have a primary amine (-NH2) as a functional group. It is also preferable that the solid organic compound having an amino group contain an aromatic ring.

[0037] Specific examples of solid organic compounds having amino groups include weakly basic anion exchange resins having amino groups. Therefore, for example, styrene-divinylbenzene copolymers having amino groups and acrylic copolymers having amino groups can be used as solid organic compounds having amino groups. These can be used alone or in combination of two or more. Examples of acrylic copolymers having amino groups include (meth)acrylic acid-divinylbenzene copolymers.

[0038] From the viewpoint of greenhouse gas adsorption performance, the exchange capacity of the weakly basic anion exchange resin is preferably 0.6 meq / mL or more, more preferably 1.0 meq / mL or more, and even more preferably 1.4 meq / mL or more. The exchange capacity of the weakly basic anion exchange resin is measured by the tapping method, in which 10 mL of the ion exchange resin is treated with hydrochloric acid, the excess hydrochloric acid is washed off with ethanol, and ammonia water is passed through the resin, and the amount of chloride ions that flow out is measured.

[0039] The adsorbent is preferably dispersed in the outer peripheral wall 11 and the partition walls 15. By dispersing the adsorbent in the outer peripheral wall 11 and the partition walls 15 in this manner, the amount of greenhouse gases adsorbed can be increased.

[0040] The content of the adsorbent in the outer wall 11 and the partition walls 15 constituting the honeycomb structure 10 is not particularly limited, but is preferably 40 to 94 mass %, more preferably 50 to 92 mass %, and even more preferably 60 to 90 mass %. By setting the content within such a range, the proportion of the adsorbent can be increased, thereby improving the adsorption performance of greenhouse gases.

[0041] The outer peripheral wall 11 and the partition walls 15 constituting the honeycomb structure 10 can contain a binder. By including a binder in the outer peripheral wall 11 and the partition walls 15, the strength of the honeycomb structure 10 can be ensured. The binder may be an organic binder or an inorganic binder. The organic binder and the inorganic binder may each be contained alone or in combination of two or more types.

[0042] Examples of organic binders include methyl cellulose, hydroxypropyl methyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, carboxymethyl cellulose, polyvinyl alcohol, hydroxyethyl methyl cellulose, polyvinyl acetal, polyethylene oxide, polyvinyl butyral, polybutadiene, methacrylic acid ester, acrylic, ethyl cellulose, silicone, polyolefin, etc. In particular, the use of water-soluble organic binders such as methyl cellulose, hydroxypropyl methyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, carboxymethyl cellulose, polyvinyl alcohol, hydroxyethyl methyl cellulose, polyvinyl acetal, polyethylene oxide, etc. can reduce environmental impact, the risk of organic solvent vapor during drying, and production costs.

[0043] Examples of inorganic binders include clay, diatomaceous earth, layered clay minerals, montmorillonite, hydrotalcite, activated clay, acid clay, hectorite, halloysite, attapulgite, silica, alumina, talc, chlorite, vermiculite, mica, illite, pyrophyllite, sericite, kaolin, sepiolite, boehmite, palygorskite, and bentonite.

[0044] The binder content in the peripheral wall 11 and partition walls 15 constituting the honeycomb structure 10 is not particularly limited, but is preferably 6 to 60 mass%, more preferably 8 to 50 mass%, and even more preferably 10 to 40 mass%. In particular, when an organic binder is used, the content is preferably 3 to 20 mass%, more preferably 5 to 15 mass%, and even more preferably 5 to 10 mass%. Furthermore, when an inorganic binder is used, the content is preferably 0 to 55 mass%, more preferably 0 to 50 mass%, and even more preferably 0 to 40 mass%.

[0045] In addition to the above components, the outer wall 11 and partition walls 15 constituting the honeycomb structure 10 may further contain known additives such as surfactants and pore-forming materials, as long as the effects of the present invention are not impaired. Specific examples of surfactants include ethylene glycol, dextrin, fatty acid soap, and polyalcohol. These may be used alone or in combination of two or more. Specific examples of pore-forming materials include wood flour, activated carbon, hollow resins, porous resins, hollow inorganic materials, and porous inorganic materials. These may be used alone or in combination of two or more.

[0046] The thickness of the peripheral wall 11 is not particularly limited, but is preferably 0.1 to 4.0 mm, more preferably 0.2 to 3.0 mm, and even more preferably 0.3 to 2.5 mm, from the viewpoint of ensuring strength. In this specification, the thickness of the peripheral wall 11 refers to the length in the normal direction to the peripheral surface of the honeycomb structure 10 from the boundary between the peripheral wall 11 and the outermost cell 14 or partition wall 15 to the peripheral surface of the honeycomb structure 10 in a cross section perpendicular to the extension direction of the cells 14.

[0047] The thickness of the partition walls 15 is not particularly limited, but is preferably 50 μm or more, more preferably 80 μm or more, and even more preferably 100 μm or more, from the viewpoint of ensuring strength. Furthermore, the thickness of the partition walls 15 is preferably 50 to 600 μm, more preferably 80 to 550 μm, and even more preferably 100 to 500 μm, from the viewpoint of suppressing pressure loss. In this specification, the thickness of the partition walls 15 is defined as the length of the portion of a line segment connecting the centers of gravity of adjacent cells 14 that passes through the partition wall 15 in a cross section perpendicular to the extension direction of the cells 14. Furthermore, the thickness of the partition walls 15 refers to the average thickness of all the partition walls 15 in the honeycomb structure 10.

[0048] It is preferable that the thickness of the outer wall 11 is the same as that of the partition walls 15. With this configuration, it is possible to ensure the strength of the honeycomb structure 10 while suppressing an increase in pressure loss and increasing the amount of greenhouse gases adsorbed.

[0049] The total pore volume of the partition wall 15 is not particularly limited, but is preferably 0.2 to 1.5 cm3 / g, and 0.3 to 1.0 cm 3 / g. By controlling the total pore volume within this range, greenhouse gases can be easily diffused into the honeycomb structure 10 through the pores of the partition walls 15, thereby increasing the amount of greenhouse gas adsorption. In this specification, the total pore volume can be measured by mercury intrusion porosimetry using a mercury porosimeter in accordance with JIS R1655:2003.

[0050] The average pore diameter of the partition walls 15 is not particularly limited, but is preferably 0.1 to 15 μm, and more preferably 0.3 to 8.0 μm. By controlling the average pore diameter within this range, greenhouse gases can be easily diffused into the honeycomb structure 10 through the pores of the partition walls 15, thereby increasing the amount of greenhouse gas adsorption. In this specification, the average pore diameter can be measured by mercury intrusion porosimetry using a mercury porosimeter in accordance with JIS R1655:2003.

[0051] The cell density (the number of cells 14 per unit cross-sectional area) of the honeycomb structure 10 is not particularly limited, but is preferably 8 to 124 cells / cm. 2 , more preferably 16 to 62 cells / cm 2 By controlling the cell density within this range, it becomes easier to obtain the effect of suppressing an increase in pressure loss, and the effect of improving the mechanical strength and the amount of greenhouse gas adsorption. 2 If the cell density is less than 124 cells / cm, the mechanical strength and the amount of greenhouse gases adsorbed are likely to decrease. 2 When the cell density exceeds this value, the pressure loss is likely to increase. Here, in this specification, the cell density is calculated by dividing the number of cells 14 in the honeycomb structure 10 by the area of ​​one end face of the honeycomb structure 10 excluding the outer wall 11.

[0052] The shape of the cells 14 in a cross section perpendicular to the extension direction of the cells 14 is not particularly limited, but is preferably a rectangle, a hexagon, an octagon, a circle, or a combination thereof. Among these, square and hexagonal shapes are preferred for the shape of the cells 14. By configuring the cells 14 in this way, an increase in pressure loss when a process gas is flowed through the honeycomb structure 10 can be suppressed.

[0053] (1-2) Elastic Sheet 20 As described above, the elastic sheet 20 has a plurality of through holes 21. The through holes 21 are not particularly limited, but preferably have the same shape as a cross section perpendicular to the extension direction of the cells 14 of the honeycomb structure 10. For example, as shown in FIG. 1B , when the cross section perpendicular to the extension direction of the cells 14 of the honeycomb structure 10 is quadrangular, the shape of the through holes 21 may also be quadrangular. By making the shape of the through holes 21 the same as the cross-sectional shape of the honeycomb structure 10, it becomes easier to insert the honeycomb structure 10 into the through holes 21.

[0054] The diameter of the through holes 21 is preferably 5 to 15% smaller than the outer diameter of a cross section perpendicular to the extension direction of the cells 14 of the honeycomb structure 10 when shrunk (when dried). By reducing the diameter of the through holes 21 in this way, it becomes possible to stably hold the honeycomb structure 10 in the through holes 21 even when the honeycomb structure 10 shrinks and expands. Here, the diameter of the through holes 21 in this specification means the diameter if the shape is circular, and means the circle-equivalent diameter if the shape is other than circular.

[0055] The number of through-holes 21 is not particularly limited and may be appropriately adjusted depending on the size of the reactor to be produced. From the viewpoint of enhancing the adsorption of greenhouse gases, the number of through-holes 21 is preferably 2 to 100, more preferably 4 to 80, and even more preferably 9 to 50.

[0056] The thickness of the elastic sheet 20 is not particularly limited, but is preferably 0.3 to 10 mm, more preferably 0.5 to 9 mm, and even more preferably 1 to 8 mm. By using an elastic sheet 20 with such a thickness, the honeycomb structure 10 can be stably held in the through-hole 21 and the expansion of the honeycomb structure 10 can be efficiently absorbed.

[0057] The number and positions of the elastic sheets 20 are not particularly limited as long as they can hold the honeycomb structure 10, but it is preferable that they are arranged in at least two places on the inflow end face 12 side and the outflow end face 13 side of the honeycomb structure 10. By arranging the elastic sheets 20 in such positions, the honeycomb structure 10 can be stably held in the through holes 21.

[0058] The material of the elastic sheet 20 is not particularly limited as long as it has elasticity. Specifically, the elastic sheet 20 has rubber elasticity and a Shore A hardness of 10 to 80 degrees, preferably 20 to 70 degrees. The Shore A hardness is measured in accordance with JIS K6253-5:2012. A typical elastic sheet 20 suitable for the present invention is a rubber sheet. By using a rubber sheet, the honeycomb structure 10 can be stably held in the through-holes 21 and expansion of the honeycomb structure 10 can be efficiently absorbed. The rubber material of the rubber sheet is not particularly limited, but examples thereof include silicone rubber, urethane rubber, butadiene rubber, natural rubber, styrene-butadiene rubber, ethylene-propylene copolymer rubber (EP rubber, EPDM rubber), butyl rubber, and vinyl chloride rubber.

[0059] It is preferable that the end (outer peripheral end) of the elastic sheet 20 is fixed to the tubular member 30. The method for fixing the elastic sheet 20 is not particularly limited, and an adhesive or other known fixing means may be used.

[0060] (1-3) Cylindrical Member 30 The cylindrical member 30 is a member that houses a plurality of honeycomb structures 10 and elastic sheets 20. The cylindrical member 30 is not particularly limited as long as it can house a plurality of honeycomb structures 10 and elastic sheets 20. For example, the cylindrical member 30 may be a straight tube, or may have a structure with a reduced diameter and / or an expanded diameter in part.

[0061] The material of the cylindrical member 30 is not particularly limited, but is preferably a metal from the viewpoint of manufacturability. Examples of metals that can be used include stainless steel, titanium alloys, copper alloys, aluminum alloys, and brass. Among these, stainless steel is preferred because of its high durability, reliability, and low cost.

[0062] The thickness of the cylindrical member 30 is not particularly limited, but from the viewpoint of durability and reliability, it is preferably 0.1 mm or more, more preferably 0.3 mm or more, and even more preferably 0.5 mm or more. Moreover, from the viewpoint of weight reduction, the thickness of the cylindrical member 30 is preferably 10 mm or less, more preferably 5 mm or less, and even more preferably 3 mm or less.

[0063] (1-4) Other Components The reactor according to the embodiment of the present invention may further include frame-shaped lid members disposed on both end surfaces of the cylindrical member 30. Here, FIG. 5A shows a schematic cross-sectional view of a reactor having a frame-shaped lid member, the cross-sectional view being parallel to the process gas flow direction. FIG. 5B shows a schematic view of one end surface of the reactor in FIG. 5A . The reactor shown in FIGS. 5A and 5B includes frame-shaped lid members 40 on both end surfaces of the cylindrical member 30. The elastic sheet 20 is fixed by sandwiching the end (outer peripheral end) of the elastic sheet 20 between the cylindrical member 30 and the frame-shaped lid member 40. Fixing the elastic sheet 20 using the frame-shaped lid member 40 in this manner facilitates fixing the elastic sheet 20 and also prevents the elastic sheet 20 from peeling off from the cylindrical member 30 or shifting within the cylindrical member 30.

[0064] The frame-shaped lid member 40 preferably has a frame shape that does not obstruct the flow of each gas during adsorption and desorption of greenhouse gases. Specifically, when looking at both end faces of the reactor, it is preferable that the inlet end face 12 and the outlet end face 13 of the honeycomb structure 10 are not covered by the frame-shaped lid member 40 during both adsorption and desorption of greenhouse gases. This allows for efficient adsorption and desorption of greenhouse gases in the reactor.

[0065] The structure of the frame-shaped cover member 40 that sandwiches the elastic sheet 20 between itself and the cylindrical member 30 is not particularly limited, and may have, for example, an L-shaped structure as shown in Fig. 5A in a cross section parallel to the flow direction of the greenhouse gas. Such an L-shaped structure makes it easy to sandwich the elastic sheet 20 between itself and the cylindrical member 30.

[0066] The material of the frame-shaped lid member 40 is not particularly limited, but is preferably a metal from the viewpoint of manufacturability. Examples of metals that can be used include stainless steel, titanium alloys, copper alloys, aluminum alloys, and brass. Among these, stainless steel is preferred because of its high durability, reliability, and low cost.

[0067] (2. Greenhouse gas recovery method and desorption method) The greenhouse gas recovery method and desorption method according to the embodiment of the present invention are carried out using the above-mentioned reactor. Specifically, the greenhouse gas recovery method according to the embodiment of the present invention includes flowing a treatment gas containing a greenhouse gas through a plurality of honeycomb structures 10 in a reactor, adsorbing the greenhouse gas in the treatment gas by an adsorbent while the treatment gas passes through the plurality of honeycomb structures 10, and causing the treatment gas with a reduced greenhouse gas concentration to flow out of the honeycomb structure 10.

[0068] Furthermore, a method for desorbing greenhouse gases according to an embodiment of the present invention includes flowing a desorbed gas or a heated desorbed gas through a plurality of honeycomb structures 10 in a reactor in which the greenhouse gas has been adsorbed, and desorbing the greenhouse gas from the adsorbent into the desorbed gas while the desorbed gas passes through the plurality of honeycomb structures 10. The desorbed gas is not particularly limited as long as it is a gas capable of desorbing carbon dioxide, and may be, for example, water vapor. The water vapor is preferably at a high temperature of 80°C or higher. The desorbed gas may be heated by a heater or by mixing with a high-temperature gas.

[0069] (3. Manufacturing Method of Reactor) The manufacturing method of the reactor according to the embodiment of the present invention is not particularly limited as long as it is a method capable of manufacturing the above-mentioned reactor. Hereinafter, a method suitable for manufacturing the reactor according to the embodiment of the present invention will be described.

[0070] First, the honeycomb structure 10 used in the reactor is manufactured by a method including a clay preparation step (first step), a molding step into a honeycomb molded body (second step), and a drying step of the honeycomb molded body (third step).

[0071] The clay preparation step (first step) is a step of kneading a forming raw material containing a carbon dioxide adsorbent and a binder to prepare a clay. The forming raw material may further contain a solvent. The solvent (dispersion medium) is not particularly limited, and examples thereof include water and a mixed solvent of water and an organic solvent such as alcohol, but water is particularly preferred.

[0072] The content of the adsorbent excluding the solvent in the forming raw material is preferably 40 to 94% by mass, more preferably 50 to 92% by mass, and even more preferably 60 to 90% by mass, from the viewpoint of achieving a good balance between greenhouse gas adsorption performance, crack suppression during drying, and water resistance. From the same viewpoint, the content of the binder excluding the solvent in the forming raw material is preferably 6 to 60% by mass, more preferably 8 to 50% by mass, and even more preferably 10 to 40% by mass. In particular, when an organic binder is used, the organic binder content excluding the solvent in the forming raw material is preferably 3 to 20% by mass, more preferably 5 to 15% by mass, and even more preferably 5 to 10% by mass. In addition, when an inorganic binder is used, the inorganic binder content excluding the solvent in the forming raw material is preferably 0 to 55% by mass, more preferably 0 to 50% by mass, and even more preferably 0 to 40% by mass. The solvent content in the forming raw material is adjusted so as to obtain a clay with a hardness suitable for molding (particularly extrusion molding).

[0073] The molding raw materials containing the above-mentioned components can be kneaded using a known kneader, and it is desirable to carry out the kneading for a time required for each component to be uniformly distributed in the clay.

[0074] The forming step (second step) into a honeycomb formed body is a step of forming the clay obtained in the first step into a honeycomb formed body. Specifically, in the second step, the honeycomb formed body is extruded to have an outer peripheral wall 11 and partition walls 15 disposed inside the outer peripheral wall 11 and defining a plurality of cells 14 extending from an inlet end face 12 to an outlet end face 13. In the extrusion forming, a die having a desired overall shape, cell shape, partition wall thickness, cell density, etc. can be used.

[0075] The honeycomb formed body drying step (third step) is a step of drying the honeycomb formed body obtained in the second step. Because the honeycomb formed body immediately after molding contains a solvent, the solvent is removed by drying. This drying step also allows at least a portion of the carbon dioxide adsorbent and the reactive organic binder to react with each other. Conventional drying methods, such as hot air drying, microwave drying, dielectric drying, reduced-pressure drying, vacuum drying, and freeze drying, can be used for drying. Among these, hot air drying, microwave drying, dielectric drying, or a combination thereof is preferred because it allows the entire honeycomb formed body to be dried quickly and uniformly. From the viewpoints of promoting the reaction between the carbon dioxide adsorbent and the reactive organic binder during drying and suppressing decomposition of the carbon dioxide adsorbent and the organic binder, the honeycomb formed body is preferably dried in an air atmosphere at 20 to 150°C, more preferably in an air atmosphere at 30 to 140°C, and even more preferably in an air atmosphere at 40 to 130°C.

[0076] Next, the plurality of honeycomb structures 10 obtained above are inserted into the plurality of through holes 21 of the elastic sheet 20 and housed in the tubular member 30. The end (outer peripheral end) of the elastic sheet 20 is fixed to the tubular member 30 using an adhesive or a known fixing means. Alternatively, when frame-shaped cover members 40 are provided on both end surfaces of the tubular member 30, the end (outer peripheral end) of the elastic sheet 20 is fixed by sandwiching it between the tubular member 30 and the frame-shaped cover members 40.

[0077] (4. Gas Recovery Apparatus) A gas recovery apparatus according to an embodiment of the present invention includes the above-described reactor. Since this gas recovery apparatus includes the above-described reactor, it is possible to suppress damage due to expansion of the honeycomb structure 10 and displacement due to expansion and contraction of the honeycomb structure 10, and the greenhouse gas recovery efficiency is less likely to decrease.

[0078] The gas recovery device according to the embodiment of the present invention may further include a gas supply pipe capable of supplying the treatment gas and / or desorbed gas (purge gas) to the reactor, and a gas exhaust pipe capable of exhausting the treatment gas or desorbed gas (purge gas) from the reactor. A gas recovery device having such a structure can easily achieve the recovery and desorption of greenhouse gases.

[0079] REFERENCE SIGNS LIST 10 honeycomb structure 11 outer peripheral wall 12 inlet end face 13 outlet end face 14 cells 15 partition walls 20 elastic sheet 21 through holes 30 cylindrical member 40 frame-shaped lid member

Claims

1. A reactor comprising: a peripheral wall; and partition walls disposed inside the peripheral wall and defining a plurality of cells extending from an inlet end face to an outlet end face, wherein the peripheral wall and the partition walls contain an adsorbent capable of adsorbing and desorbing greenhouse gases; an elastic sheet having a plurality of through holes and holding the surfaces of the peripheral wall parallel to the extension direction of the cells so as to face each other at a predetermined interval by inserting the plurality of honeycomb structures into the plurality of through holes; and a cylindrical member that houses the plurality of honeycomb structures and the elastic sheet.

2. A reactor according to claim 1, wherein the elastic sheet is disposed at least at two locations on the inflow end face side and the outflow end face side of the honeycomb structure.

3. The reactor according to claim 2, further comprising frame-shaped lid members disposed on both end surfaces of the cylindrical member, and the elastic sheet is fixed by sandwiching the ends of the elastic sheet between the cylindrical member and the frame-shaped lid members.

4. A reactor according to claim 1 or 2, wherein the through holes of the elastic sheet have the same shape as a cross section of the honeycomb structure perpendicular to the direction in which the cells extend.

5. A reactor according to claim 4, wherein the diameter of the through holes in the elastic sheet is 5 to 15% smaller than the outer diameter of a cross section perpendicular to the cell extension direction of the honeycomb structure when contracted.

6. The reactor according to claim 1 or 2, wherein the thickness of the elastic sheet is 0.3 to 10 mm.

7. A reactor according to claim 1 or 2, wherein the honeycomb structure has an expansion rate of 3 to 20% of the outer diameter when expanded relative to the outer diameter when contracted in a cross section perpendicular to the direction in which the cells extend.

8. The reactor according to claim 1 or 2, wherein the elastic sheet is a rubber sheet.

9. The reactor according to claim 1 or 2, wherein the adsorbent is an amine compound.

10. The reactor of claim 1 or 2, wherein the greenhouse gas is carbon dioxide.

11. A gas recovery system comprising the reactor of claim 1 or 2.

Images