Honeycomb structure, method for producing same, and carbon dioxide recovery device

Abstract

Provided is a honeycomb structure having multiple cell channels that pass through the inside of the structure and are demarcated by walls 20. The walls 20 contain a carbon dioxide adsorbent and a binder. The binder is made of a water-insoluble organic binder.

Description

Honeycomb structure, its manufacturing method, and carbon dioxide recovery device

[0001] The present invention relates to a honeycomb structure, a method for manufacturing the same, and a carbon dioxide 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] The CO2 adsorbed in the honeycomb structure is desorbed by passing a purge gas such as water vapor through the cells. The honeycomb structure described in Patent Document 1 is manufactured by extrusion molding a mixture of inorganic powder components, an organic binder, and an amine polymer, but is not fired. As a result, the organic binder dissolves in the water vapor during CO2 desorption, which can cause a decrease in the strength of the honeycomb structure or damage it.

[0006] The present invention has been made to solve the above-mentioned problems, and aims to provide a honeycomb structure that can suppress strength reduction and breakage during carbon dioxide desorption, a method for manufacturing the same, and a carbon dioxide recovery device.

[0007] The present inventors have conducted extensive research into honeycomb structures having partition walls containing a carbon dioxide adsorbent and a binder, and have found that the use of a water-insoluble organic binder as the binder can suppress a decrease in strength and breakage during carbon dioxide desorption, leading to the completion of the present invention. That is, the present invention is exemplified as follows.

[0008] <1> A honeycomb structure having a plurality of cell channels that pass through the interior of the honeycomb structure and are separated by partition walls, the partition walls containing a carbon dioxide adsorbent and a binder, the binder being made of a water-insoluble organic binder.

[0009] <2> The honeycomb structure according to <1>, wherein the water-insoluble organic binder is at least one selected from the group consisting of polyvinyl butyral, alkyl acetalized polyvinyl alcohol compounds, ethyl cellulose, polyvinylidene fluoride, acrylic esters, acrylic resins, and alkyd resins.

[0010] <3> The honeycomb structure according to <1> or <2>, wherein the content of the carbon dioxide adsorbent in the partition walls is 50 to 90 mass %.

[0011] <4> The honeycomb structure according to any one of <1> to <3>, wherein the carbon dioxide adsorbent is a solid organic compound having at least one selected from an amino group and an ammonium group.

[0012] <5> The honeycomb structure according to <4>, wherein the solid organic compound is an anion exchange resin having at least one selected from an amino group and an ammonium group.

[0013] <6> The honeycomb structure according to <4>, wherein the solid organic compound is a styrene-divinylbenzene copolymer having one or more selected from an amino group and an ammonium group, and / or an acrylic copolymer having one or more selected from an amino group and an ammonium group.

[0014] <7> A method for manufacturing a honeycomb structure, comprising: a step of kneading a forming raw material containing a carbon dioxide adsorbent, a binder, and a water-soluble solvent, wherein the binder is a water-insoluble organic binder, to prepare a clay; a step of molding the clay into a honeycomb formed body, the honeycomb formed body having a plurality of cell channels that pass through the interior and are separated by partition walls; a step of removing the water-soluble solvent by immersing the honeycomb formed body in water; and a step of drying the honeycomb formed body.

[0015] <8> The method for manufacturing a honeycomb structure according to <7>, wherein the water-insoluble organic binder is at least one selected from the group consisting of polyvinyl butyral, alkyl acetalized polyvinyl alcohol compounds, ethyl cellulose, polyvinylidene fluoride, acrylic resins, and alkyd resins.

[0016] <9> The method for manufacturing a honeycomb structure according to <7> or <8>, wherein the content of the carbon dioxide adsorbent excluding the water-soluble solvent in the forming raw material is 50 to 90 mass%, and the content of the binder excluding the water-soluble solvent in the forming raw material is 10 to 50 mass%.

[0017] <10> The method for manufacturing a honeycomb structure according to any one of <7> to <9>, wherein the water-soluble solvent is at least one selected from the group consisting of acetone, methyl ethyl ketone, ethanol, 1-propanol, isopropyl alcohol, propylene glycol monomethyl ether, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, tetrahydrofuran, N,N-dimethylformamide, N-methyl-2-pyrrolidone, and dimethyl sulfoxide.

[0018] <11> A carbon dioxide recovery device comprising one or more honeycomb structures according to any one of <1> to <6>.

[0019] According to the present invention, it is possible to provide a honeycomb structure capable of suppressing a decrease in strength and breakage during carbon dioxide desorption, a method for manufacturing the same, and a carbon dioxide recovery device.

[0020] 1A is a schematic diagram of an end face perpendicular to the cell extension direction of a honeycomb structure according to an embodiment of the present invention, and FIG. 1B is a schematic diagram of a cross section taken along line aa' in FIG.

[0021] The honeycomb structure of the present invention has a plurality of cell channels that pass through the interior and are separated by partition walls, and the partition walls contain a carbon dioxide adsorbent (hereinafter abbreviated as "adsorbent") and a binder, the binder being a water-insoluble organic binder. Because the honeycomb structure of the present invention uses a water-insoluble organic binder as the binder, the binder does not dissolve even when it comes into contact with water vapor during carbon dioxide desorption. Therefore, the honeycomb structure of the present invention can suppress a decrease in strength and breakage during carbon dioxide desorption.

[0022] 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.

[0023] (1. Honeycomb structure) Fig. 1A is a schematic diagram of an end face perpendicular to the cell extension direction of a honeycomb structure 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 parallel to the cell extension direction).

[0024] As shown in FIGS. 1A and 1B , the honeycomb structure has a plurality of cells 30 (cell channels) that pass through the interior and are separated by partition walls 20. Specifically, the honeycomb structure includes an outer peripheral wall 10 and partition walls 20 disposed on the inner periphery of the outer peripheral wall 10, extending from a first end face 40 to a second end face 50, and separating the plurality of cells 30 that form fluid flow paths. The plurality of cells 30 are arranged parallel to one another. The honeycomb structure is a flow-through type in which both end faces (first end face 40 and second end face 50) of each cell 30 are open. When a gas containing carbon dioxide (e.g., air) flows in through the first end face 40 where the inlets of the plurality of cells 30 are located, the carbon dioxide is adsorbed as it passes through the plurality of cells 30, and the gas with a reduced carbon dioxide concentration flows out from the second end face 50 where the outlets of the plurality of cells 30 are located.

[0025] The end face shape of the honeycomb structure 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. The outer shape of the honeycomb structure may typically be a columnar shape. The honeycomb structure shown in Figures 1A and 1B has a square end face shape and is an example of a square columnar shape as a whole.

[0026] The length of the honeycomb structure in the direction in which the cells 30 extend (the length from the first end face 40 to the second end face 50) is not particularly limited and may be set appropriately depending on the application and required performance. However, while a longer length of the honeycomb structure in the direction in which the cells 30 extend can increase the amount of carbon dioxide adsorption, 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.

[0027] The diameter of each end face of the honeycomb structure 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 can increase the amount of carbon dioxide adsorption, if the diameter is too large, manufacturing becomes more difficult. Therefore, the diameter is preferably 20 to 450 mm, more preferably 20 to 400 mm, and even more preferably 20 to 350 mm. Here, the diameter of each end face of the honeycomb structure in this specification means the diameter if the shape is circular, and means the circle-equivalent diameter if the shape is other than circular.

[0028] The partition walls 20 constituting the honeycomb structure contain an adsorbent and a binder. The outer peripheral wall 10 constituting the honeycomb structure can also contain an adsorbent and a binder, similar to the partition walls 20. The binder is made of a water-insoluble organic binder and does not contain any other binders.

[0029] Here, in this specification, "water-insoluble organic binder" refers to an organic binder with an undissolved fraction of 80% or more, as measured by the following method. 1 g of organic binder is added to 99 g of hot water (80°C) while stirring at 300 rpm with a stirrer, and the mixture is stirred and mixed for 24 hours. The mixture is then cooled to 25°C, and the organic binder that has not dissolved in the aqueous phase is separated by filtration and dried at 120°C for 90 minutes. The mass of the organic binder after drying is measured to determine the undissolved mass of the organic binder. The undissolved fraction is then calculated using the amount of organic binder added (1 g) and the undissolved mass using the following formula: Undissolved fraction (%) = Undissolved mass of organic binder (g) / Amount of organic binder added (1 g) × 100

[0030] By using a water-insoluble organic binder as the binder, the binder does not dissolve even when it comes into contact with water vapor during carbon dioxide desorption, thereby suppressing strength reduction and breakage during carbon dioxide desorption. Furthermore, although the adsorbent tends to absorb water and expand during carbon dioxide desorption, using a water-insoluble organic binder can also suppress the expansion of the adsorbent. Furthermore, by incorporating an adsorbent into the partition walls 20 and the outer peripheral wall 10, carbon dioxide adsorption becomes possible. Furthermore, compared to conventional honeycomb structures in which an adsorbent is coated on the surfaces of the partition walls 20 and the outer peripheral wall 10, this structure is manufactured without a high-temperature firing process, thereby reducing the amount of carbon dioxide generated during manufacturing. Furthermore, the amount of adsorbent supported can be increased, thereby increasing the amount of carbon dioxide adsorbed.

[0031] The water-insoluble organic binder is not particularly limited, but examples thereof include polyvinyl butyral, alkyl acetalized polyvinyl alcohol compounds, ethyl cellulose, polyvinylidene fluoride, acrylic esters, acrylic resins, and alkyd resins. These can be used alone or in combination of two or more. By selecting and using such a water-insoluble organic binder, it is possible to stably suppress the decrease in strength and breakage of the honeycomb structure when carbon dioxide is desorbed.

[0032] The content of the water-insoluble organic binder in the honeycomb structure (partition walls 20 and peripheral wall 10) is not particularly limited, but is preferably 10 to 50 mass%, more preferably 12 to 30 mass%, and even more preferably 15 to 25 mass%. By setting the content within such a range, it is possible to improve the carbon dioxide adsorption performance while ensuring the strength of the honeycomb structure.

[0033] The adsorbent is not particularly limited, and known adsorbents can be used. Among them, the adsorbent is preferably one or more of an amino group (-NH, -NHR, -NRR' (R and R' represent organic groups)) and an ammonium group (-N +Preferably, the adsorbent is a solid organic compound having one or more selected from the group consisting of aryl, ...

[0034] The solid organic compound having one or more selected from the amino group and the ammonium group is preferably water-insoluble from the viewpoint of water resistance. The solid organic compound having one or more selected from the amino group and the ammonium group is preferably —NH2, —NHR, —NRR′, —N + The solid organic compound may have any of RR'R" (R, R', and R" represent organic groups), or may have two or more of these in combination. Among amino groups, it is particularly preferable to have a primary amine (-NH2) as a functional group. It is also preferable that the solid organic compound having one or more selected from amino groups and ammonium groups contains an aromatic ring.

[0035] Specific examples of solid organic compounds having one or more groups selected from amino groups and ammonium groups include anion exchange resins having one or more groups selected from amino groups and ammonium groups. For example, weakly basic anion exchange resins having amino groups, strongly basic anion exchange resins having ammonium groups, etc. can be used as this anion exchange resin. Furthermore, solid organic compounds having one or more groups selected from amino groups and ammonium groups include styrene-divinylbenzene copolymers having one or more groups selected from amino groups and ammonium groups, and acrylic copolymers having one or more groups selected from amino groups and ammonium groups. These can be used alone or in combination of two or more. Examples of styrene-divinylbenzene copolymers having one or more groups selected from amino groups and ammonium groups include copolymers of styrene and divinylbenzene. Examples of acrylic copolymers having one or more groups selected from amino groups and ammonium groups include (meth)acrylic acid-divinylbenzene copolymers. While OH-type, Cl-type, HCO3-type, etc. can be used as anion exchange resins having ammonium groups, from the viewpoint of carbon dioxide adsorption performance, OH-type or HCO3-type are preferred. That is, the counter anion of the ammonium group is OH ― or HCO3 ― is preferred.

[0036] From the viewpoint of carbon dioxide adsorption performance, the exchange capacity of the 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. Here, the exchange capacity of an anion exchange resin having amino groups is measured by the tapping method, where 10 mL of the ion exchange resin is treated with hydrochloric acid, the excess hydrochloric acid is washed with ethanol, and the amount of chloride ions that flow out when aqueous ammonia is passed through. Furthermore, the exchange capacity of an anion exchange resin having ammonium groups is measured by the tapping method, where 10 mL of the ion exchange resin is treated with hydrochloric acid, the excess hydrochloric acid is washed with ethanol, and the amount of chloride ions that flow out when aqueous sodium hydroxide solution is passed through.

[0037] The content of the adsorbent in the honeycomb structure (partition walls 20 and outer peripheral wall 10) is not particularly limited, but is preferably 50 to 90 mass%, more preferably 70 to 88 mass%, and even more preferably 75 to 85 mass%. By setting the content within such a range, the proportion of the adsorbent can be increased, thereby improving the carbon dioxide adsorption performance.

[0038] In addition to the above components, the honeycomb structure (partition walls 20 and peripheral wall 10) may further contain known additives such as surfactants and pore formers, 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 formers 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.

[0039] The thickness of the peripheral wall 10 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 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 30 or partition wall 20 in a cross section perpendicular to the extension direction of the cells 30.

[0040] The thickness of the partition wall 20 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. Moreover, the thickness of the partition wall 20 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.

[0041] It is preferable that the thickness of the outer peripheral wall 10 is the same as that of the partition walls 20. With such a configuration, it is possible to suppress an increase in pressure loss and increase the amount of carbon dioxide adsorption while ensuring the strength of the honeycomb structure.

[0042] The cell density of the honeycomb structure (the number of cells 30 per unit cross-sectional area) 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 carbon dioxide adsorption. 2 If the cell density is less than 124 cells / cm, the mechanical strength and the amount of carbon dioxide adsorption tend 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 30 in the honeycomb structure by the area of ​​one end face excluding the outer wall 10 of the honeycomb structure.

[0043] The shape of the cells 30 in a cross section perpendicular to the extension direction of the cells 30 of the honeycomb structure is not particularly limited, but is preferably a quadrangle (for example, a square), a hexagon, an octagon, a circle, or a combination thereof. Among these, square and hexagonal shapes are preferred for the shape of the cells 30. By configuring the cells 30 in this way, it is possible to suppress an increase in pressure loss when gas is flowed through the honeycomb structure.

[0044] (2. Carbon Dioxide Capture Method and Desorption Method) The carbon dioxide capture method and desorption method according to an embodiment of the present invention are carried out using the above-described honeycomb structure. Specifically, the carbon dioxide capture method according to an embodiment of the present invention includes flowing a gas containing carbon dioxide through a plurality of cells 30 (cell channels) of the honeycomb structure, adsorbing the carbon dioxide in the gas by an adsorbent while the gas passes through the plurality of cells 30 (cell channels), and discharging the gas with a reduced carbon dioxide concentration from the honeycomb structure. The gas is not particularly limited as long as it contains carbon dioxide, and examples thereof include environmental air (outdoor air, as well as indoor or indoor air), factory exhaust gas, ship exhaust gas, and power plant exhaust gas.

[0045] Furthermore, a carbon dioxide desorption method according to an embodiment of the present invention includes flowing a desorbed gas or a heated desorbed gas through a plurality of cells 30 (cell channels) of a honeycomb structure in which carbon dioxide has been adsorbed, and desorbing carbon dioxide from the adsorbent into the desorbed gas as the desorbed gas passes through the plurality of cells 30. 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.

[0046] (3. Manufacturing Method of Honeycomb Structure) The manufacturing method of the honeycomb structure according to the embodiment of the present invention is not particularly limited as long as it is a method that can manufacture the above-mentioned honeycomb structure. Hereinafter, a method suitable for manufacturing the honeycomb structure according to the embodiment of the present invention will be described.

[0047] A method for manufacturing a honeycomb structure according to an embodiment of the present invention includes a clay preparation process (first process), a molding process into a honeycomb formed body (second process), a water immersion process of the honeycomb formed body (third process), and a drying process of the honeycomb formed body (fourth process).

[0048] The clay preparation step (first step) is a step of kneading a molding raw material containing an adsorbent, a binder, and a water-soluble solvent, the binder being a water-insoluble organic binder, to prepare a clay. Examples of the water-soluble solvent include, but are not limited to, acetone, methyl ethyl ketone, ethanol, 1-propanol, isopropyl alcohol, propylene glycol monomethyl ether, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, tetrahydrofuran, N,N-dimethylformamide, N-methyl-2-pyrrolidone, and dimethyl sulfoxide. These may be used alone or in combination of two or more.

[0049] The content of the adsorbent excluding the water-soluble solvent in the forming raw material is preferably 50 to 90% by mass, more preferably 70 to 88% by mass, and even more preferably 75 to 85% by mass, from the viewpoint of achieving a good balance between carbon dioxide adsorption performance, crack suppression during drying, and water resistance. From the same viewpoint, the content of the binder excluding the water-soluble solvent in the forming raw material is preferably 10 to 50% by mass, more preferably 12 to 30% by mass, and even more preferably 15 to 25% by mass. The content of the water-soluble solvent in the forming raw material is adjusted so as to obtain a clay having a hardness suitable for forming (particularly, extrusion forming).

[0050] 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. The honeycomb formed body has a plurality of cells 30 (cell channels) that pass through the interior and are partitioned by partition walls 20. Specifically, in the second step, extrusion is performed to form a honeycomb formed body that includes an outer peripheral wall 10 and partition walls 20 that are disposed on the inner peripheral side of the outer peripheral wall 10, extend from a first end face 40 to a second end face 50, and partition the plurality of cells 30 that form fluid flow paths. During extrusion, a die having a desired overall shape, cell shape, partition wall thickness, cell density, etc. can be used.

[0051] The water immersion step (third step) of the honeycomb formed body is a step of removing the water-soluble solvent by immersing the honeycomb formed body in water. By removing the water-soluble solvent, the partition walls 20 become porous. The immersion time is not particularly limited and may be adjusted appropriately depending on the size of the honeycomb formed body, but is preferably 30 to 120 minutes from the viewpoint of the removability of the water-soluble solvent.

[0052] The honeycomb formed body drying step (fourth step) is a step of drying the honeycomb formed body obtained in the second step. Since the honeycomb formed body immediately after molding contains a solvent, the solvent is removed by drying. For drying, 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, 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 viewpoint of suppressing decomposition of the adsorbent and organic binder during drying, it is preferable to dry the honeycomb formed body 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.

[0053] (4. Carbon Dioxide Capture Apparatus) A carbon dioxide capture apparatus according to an embodiment of the present invention includes one or more of the above-described honeycomb structures. The above-described honeycomb structures can suppress a decrease in strength or breakage during carbon dioxide desorption, and therefore the performance of the carbon dioxide capture apparatus is less likely to deteriorate.

[0054] The carbon dioxide capture device according to the embodiment of the present invention may further include a housing that accommodates the honeycomb structure. The housing is preferably connected to a pipe that can supply and discharge a gas containing carbon dioxide and a desorbed gas. A carbon dioxide capture device having such a structure can easily achieve the capture and desorption of carbon dioxide.

[0055] The present invention will be described in detail below with reference to examples, but the present invention should not be construed as being limited to these examples.

[0056] <Materials Used> The following commercially available water-insoluble anion exchange resin (a styrene-based divinylbenzene polymer having a primary amine functional group with an exchange capacity of 2.0 meq / mL) was prepared as an adsorbent. Polyvinyl butyral, ethyl cellulose, and alkyl acetalized polyvinyl alcohol were prepared as water-insoluble organic binders. Methyl cellulose and polyvinyl alcohol were prepared as water-soluble organic binders. Isopropyl alcohol was prepared as a water-soluble solvent.

[0057] The adsorbent, binder, and water-soluble solvent were blended to obtain a molding raw material at the content shown in Table 1. In Table 1, the content of each component is the content in the molding raw material excluding the water-soluble solvent. Next, the molding raw material was kneaded for 30 minutes in a vacuum kneader to prepare a puddle. The amount of water-soluble solvent blended was adjusted so that the puddle would have a hardness suitable for molding.

[0058] Next, the clay was molded using an extrusion molding machine having a predetermined die structure to obtain a honeycomb molded body. The die structure was selected so that the honeycomb molded body (honeycomb structure) after drying would have the following conditions: Outer shape: rectangular columnar cell cross-sectional shape: length in the direction of extension of the rectangular cell: 30 mm, diameter of each end face: 60 mm, outer peripheral wall thickness: 1.0 mm, partition wall thickness: 200 μm, cell density: 46.5 cells / cm 2

[0059] Next, the obtained honeycomb molded body was immersed in water for 60 minutes. Next, the honeycomb molded body after immersion in water was subjected to high-frequency dielectric drying, and then dried in an air atmosphere at a temperature of 120°C for 1 minute using a microwave dryer. Then, both end faces were cut off by a predetermined amount to prepare a honeycomb structure.

[0060] The honeycomb structure obtained above was evaluated as follows.

[0061] (Expansion Coefficient in Water Immersion Test) The cell pitch of the honeycomb structure was measured using a microscope before and after immersion in water for 1 hour, and the expansion coefficient was calculated using the following formula: Expansion Coefficient [%] = Cell Pitch Size After Immersion / Cell Pitch Size Before Immersion × 100 In this evaluation, if the expansion coefficient is 10% or less, it can be determined that the expansion due to water absorption of the adsorbent is small and the size variation of the honeycomb structure is small. The "cell pitch" was determined by the following calculation: First, the area of ​​one end face (first end face or second end face) of the honeycomb structure (the total area of ​​the partition walls and cells excluding the outer peripheral wall) was divided by the number of cells to calculate the area per cell. Next, the square root of the area per cell was calculated, and this was defined as the cell pitch.

[0062] The evaluation results are shown in Table 1.

[0063]

[0064] As shown in Table 1, the honeycomb structure (Example) having partition walls containing an adsorbent and a water-insoluble organic binder had a smaller expansion coefficient than the honeycomb structure (Comparative Example) having partition walls containing an adsorbent and a water-soluble organic binder.

[0065] As can be seen from the above results, the present invention can provide a honeycomb structure capable of suppressing a decrease in strength and breakage during carbon dioxide desorption, a method for manufacturing the same, and a carbon dioxide recovery device.

[0066] 10 outer peripheral wall 20 partition wall 30 cell 40 first end surface 50 second end surface

Claims

1. A honeycomb structure having a plurality of cell channels passing through the interior of the honeycomb structure and separated by partition walls, the partition walls containing a carbon dioxide adsorbent and a binder, the binder being a water-insoluble organic binder.

2. The honeycomb structure according to claim 1, wherein the water-insoluble organic binder is one or more selected from the group consisting of polyvinyl butyral, alkyl acetalized polyvinyl alcohol compounds, ethyl cellulose, polyvinylidene fluoride, acrylic esters, acrylic resins, and alkyd resins.

3. A honeycomb structure according to claim 1 or 2, wherein the content of the carbon dioxide adsorbent in the partition walls is 50 to 90 mass %.

4. The honeycomb structure according to claim 1 or 2, wherein the carbon dioxide adsorbent is a solid organic compound having at least one group selected from the group consisting of an amino group and an ammonium group.

5. The honeycomb structure according to claim 4, wherein the solid organic compound is an anion exchange resin having at least one selected from the group consisting of an amino group and an ammonium group.

6. A honeycomb structure according to claim 4, wherein the solid organic compound is a styrene-divinylbenzene copolymer having one or more groups selected from an amino group and an ammonium group, and / or an acrylic copolymer having one or more groups selected from an amino group and an ammonium group.

7. A method for manufacturing a honeycomb structure, comprising: a step of kneading a forming raw material containing a carbon dioxide adsorbent, a binder, and a water-soluble solvent, the binder being a water-insoluble organic binder, to prepare a clay; a step of forming the clay into a honeycomb formed body, the honeycomb formed body having a plurality of cell channels passing through the interior and separated by partition walls; a step of removing the water-soluble solvent by immersing the honeycomb formed body in water; and a step of drying the honeycomb formed body.

8. A method for manufacturing a honeycomb structure according to claim 7, wherein the water-insoluble organic binder is one or more selected from polyvinyl butyral, alkyl acetalized polyvinyl alcohol compounds, ethyl cellulose, polyvinylidene fluoride, acrylic resins and alkyd resins.

9. A method for manufacturing a honeycomb structure as described in claim 7 or 8, wherein the content of the carbon dioxide adsorbent excluding the water-soluble solvent in the forming raw material is 50 to 90 mass %, and the content of the binder excluding the water-soluble solvent in the forming raw material is 10 to 50 mass %.

10. A method for manufacturing a honeycomb structure according to claim 7 or 8, wherein the water-soluble solvent is one or more selected from the group consisting of acetone, methyl ethyl ketone, ethanol, 1-propanol, isopropyl alcohol, propylene glycol monomethyl ether, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, tetrahydrofuran, N,N-dimethylformamide, N-methyl-2-pyrrolidone and dimethyl sulfoxide.

11. A carbon dioxide recovery device comprising one or more honeycomb structures according to claim 1 or 2.

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