Honeycomb structure, honeycomb structure stack, and reactor

Abstract

A honeycomb structure according to an embodiment of the present invention comprises a honeycomb structure part having an outer wall and partition walls that are disposed inside the outer wall, extend from a first end face to a second end face, and define a plurality of cells serving as flow paths of a fluid. The cell density of the plurality of cells is greater than 186 cells / cm2. A distance X cm between the first end face and the second end face, and an opening area Y cm2 of the plurality of cells satisfy the relationship Y / X ≥ 30. A honeycomb structure stack according to an embodiment of the present invention comprises two or more honeycomb structures described above.

Description

Honeycomb structure, honeycomb structure stack, and reactor

[0001] The present invention relates to a honeycomb structure, a honeycomb structure stack, and a reactor.

[0002] Conventionally, a reactor has been known in which a fluid is introduced into a space in which a catalyst is disposed, and a reaction is promoted by the catalyst. For example, a honeycomb structure having a plurality of cells defined by partition walls, in which the partition walls support a catalyst, can increase the contact area between the catalyst and the fluid and favorably promote the reaction, and is therefore widely used as a reactor for promoting a reaction for purifying automobile exhaust gas (for example, Patent Document 1).

[0003] Japanese Patent Application Laid-Open No. 2022-170972

[0004] In the reactor using the above honeycomb structure, the contact area between the catalyst and the fluid can be increased by increasing the cell density, but the pressure loss also tends to increase in inverse proportion to the square of the hydraulic diameter of the cell.

[0005] In view of the above, a main object of the present invention is to provide a honeycomb structure having an increased cell density while suppressing an increase in pressure loss.

[0006] [1] According to one aspect of the present invention, there is provided a honeycomb structure part having an outer wall and partition walls disposed inside the outer wall, the partition walls extending from a first end face to a second end face and defining a plurality of cells that serve as fluid flow paths, wherein the cell density of the plurality of cells is 186 cells / cm ２ the distance between the first end surface and the second end surface is X cm, and the opening area of ​​the plurality of cells is Y cm ２[2] According to another aspect of the present invention, there is provided a honeycomb structure including: a honeycomb structure portion having an outer wall and partition walls disposed inside the outer wall and defining a plurality of cells extending from an inflow end face to an outflow end face to serve as fluid flow paths, wherein two or more honeycomb structures are disposed with at least a portion spaced apart so that the inflow end faces or the outflow end faces face each other; a fluid inflow channel forming a space on the inflow end face side of the honeycomb structure and communicating with the plurality of cells; and a fluid outflow channel forming a space on the outflow end face side of the honeycomb structure and communicating with the plurality of cells, wherein a cell density of the plurality of cells in the honeycomb structure portion is 186 cells / cm. ２ and the distance between the inlet end surface and the outlet end surface is X cm and the opening area of ​​the plurality of cells is Y cm ２and satisfy a relationship of Y / X≧30, the fluid inlet channel extends from one open end to the other closed end, and the fluid outlet channel extends from one open end to the other closed end. [3] In the honeycomb structure stack according to [2] above, a plug may be provided at the other end of the fluid inlet channel and / or the other end of the fluid outlet channel. [4] The honeycomb structure stack according to [2] or [3] above may include two of the honeycomb structures arranged at a predetermined angle so that the inlet end faces face each other and are spaced apart at the one end of the fluid inlet channel and contact each other at the other end. [5] The honeycomb structure stack according to any one of [2] to [4] above may include two honeycomb structures arranged at a predetermined angle such that the outflow end faces face each other, are spaced apart at one end of the fluid outflow channel, and are in contact at the other end. [6] In the honeycomb structure stack according to any one of [2] to [5] above, an angle formed between the extending directions of the inflow end faces facing each other and / or the extending directions of the outflow end faces facing each other may be in the range of 0°±30°. [7] In the honeycomb structure stack according to any one of [2] to [6] above, an angle formed between the extending directions of the fluid inflow channel and the fluid outflow channel may be in the range of 180°±30°. [8] In the honeycomb structure stack according to any one of [2] to [7] above, all of the honeycomb structure portions included in the two or more honeycomb structures may be made of forming materials of the same composition and have partition walls of the same structure. [9] In the honeycomb structure stack according to any one of the above [2] to [7], the honeycomb structure parts included in the two or more honeycomb structures may be made of forming materials with different compositions or may have partition walls with different structures.

[10] In the honeycomb structure stack according to any one of the above [2] to [9], the honeycomb structure part may further include a functional material supported on the partition walls.

[11] In the honeycomb structure stack according to the above item

[10] , the partition walls may be formed of a material containing the functional material, or a functional layer containing the functional material may be provided on a surface of the partition walls.

[12] According to another aspect of the present invention, there is provided a reactor including the honeycomb structure according to the above item [1] or the honeycomb structure stack according to any one of the above items [2] to

[11] .

[0007] According to an embodiment of the present invention, by adjusting the relationship between the cell opening area and the cell length, a honeycomb structure can be provided in which the cell density is increased while suppressing an increase in pressure loss. Furthermore, a honeycomb structure stack in which the above honeycomb structures are stacked via fluid inlet channels and / or fluid outlet channels can be provided, which can save space while ensuring fluid processing efficiency.

[0008] 3A is a schematic perspective view showing the configuration of a honeycomb structure according to one embodiment of the present invention. FIG. 3B is a schematic perspective view showing the configuration of a honeycomb structure according to one embodiment of the present invention. FIG. 3C is a schematic perspective view showing the configuration of a honeycomb structure stack according to one embodiment of the present invention. FIG. 3D is a schematic cross-sectional view parallel to the extension direction of a fluid inlet channel of the honeycomb structure stack shown in FIG. 3A. FIG. 3E is a schematic cross-sectional view perpendicular to the extension direction of a fluid inlet channel of the honeycomb structure stack shown in FIG. 3A. FIG. 3F is a schematic cross-sectional view parallel to the extension direction of a fluid inlet channel of the honeycomb structure stack according to one embodiment of the present invention. FIG. 3G is a schematic cross-sectional view parallel to the extension direction of a fluid inlet channel of the honeycomb structure stack according to one embodiment of the present invention. FIG. 3H is a schematic cross-sectional view of a pseudo structural unit of a honeycomb structure stack used in a simulation. FIG. 3I is a schematic cross-sectional view of a pseudo structural unit of a honeycomb structure stack used in a simulation.

[0009] Hereinafter, embodiments of the present invention will be described with reference to the drawings, but the present invention is not limited to these embodiments. Furthermore, in order to clarify the description, the drawings may show the width, thickness, shape, etc. of each part more schematically than in the embodiments, but these are merely examples and do not limit the interpretation of the present invention. Identical elements may be assigned the same reference numerals, and redundant descriptions may be omitted.

[0010] A. Honeycomb Structure A-1. Overall Configuration of Honeycomb Structure Fig. 1 is a schematic perspective view showing the configuration of a honeycomb structure according to one embodiment of the present invention. The honeycomb structure 100A includes a honeycomb structure portion 10 having an outer wall 16 and partition walls 14 disposed inside the outer wall 16 and extending from a first end face 10a to a second end face 10b to define a plurality of cells 12 that serve as fluid flow paths. Depending on the purpose, a functional material can be supported on the honeycomb structure portion 10.

[0011] The outer wall 16 typically has a cylindrical shape. The cross-sectional shape of the outer wall 16 perpendicular to the extension direction of the cells 12 (hereinafter also referred to as the "length direction") is preferably substantially rectangular, but may be other shapes such as other polygons (e.g., triangles, pentagons, hexagons), circles, or ellipses. In the illustrated example, the outer wall 16 is formed integrally with the partition walls 14. The outer wall 16 and the partition walls 14 may also be formed separately. The thickness of the outer wall 16 may be, for example, 0.1 mm to 10 mm.

[0012] The partition walls 14 are typically made of a porous body. The porosity and pore size of the partition walls 14 can be appropriately set depending on the purpose. From the viewpoint of strength, the porosity of the porous body can be, for example, 70% or less, and preferably 10% to 60%. The average pore size is preferably 90% or less, and more preferably 50% or less, of the thickness of the partition walls 14. The average pore size can be, for example, 280 μm or less, preferably 2.5 μm to 225 μm, and more preferably 5.0 μm to 180 μm. The porosity can be measured, for example, by mercury intrusion porosimetry. The average pore size is a value calculated by mercury intrusion porosimetry as the pore size that provides half the total pore volume.

[0013] The thickness of the partition walls 14 is preferably 5 μm to 300 μm, more preferably 25 μm to 250 μm, and even more preferably 50 μm to 200 μm. When the thickness of the partition walls 14 is within the above range, the desired strength of the honeycomb structure can be ensured while achieving the desired cell density and opening ratio described below. For example, by forming the partition walls to a thickness of about 5 μm, a cell density of about 20,000 cpsi can be achieved.

[0014] Each of the plurality of cells 12 is a space extending from a first end face to a second end face. In the illustrated example, the cross-sectional shape of each cell 12 perpendicular to the length direction is substantially rectangular, but it may be other shapes such as polygonal, circular, elliptical, etc.

[0015] The number of cells 12 per unit area (cell density) in the plane perpendicular to the longitudinal direction of the honeycomb structure part 10 is preferably 186 cells / cm ２ or greater than 1200 cpsi, more preferably greater than 233 particles / cm ２ or greater than 1500 cpsi, more preferably 466 particles / cm ２ If the cell density is in a range exceeding the above lower limit, the surface area of ​​the cells 12 increases, and therefore, when the partition walls support a catalyst, the contact area between the catalyst and the fluid can be increased. The upper limit of the cell density is, for example, 3100 cells / cm. ２ The cell density may be 20,000 cpsi or less. When the cell density is equal to or less than the upper limit, an excessive increase in pressure loss can be prevented. When the cell density exceeds the upper limit, production may become difficult.

[0016] The open area ratio (OFA) of the cells 12 at the first end face 10a and the second end face 10b of the honeycomb structure section 10 is preferably 30% or more, more preferably 40% or more, and even more preferably 50% or more. When the open area ratio is in the range above the lower limit, an increase in pressure loss can be suppressed. Furthermore, as a result of the reduced heat capacity, the energy required to heat the honeycomb structure section 10 can be reduced. From the viewpoint of strength, the open area ratio is preferably 95% or less.

[0017] In one embodiment, the honeycomb structure 10 satisfies all of the above-mentioned preferable cell density, opening ratio, and thickness of the partition walls 14. According to such a honeycomb structure 10, the surface area of ​​the cells 12 can be sufficiently increased while ensuring strength.

[0018] In the honeycomb structure 10, the distance L between the first end face 10a and the second end face 10b (the length of the honeycomb structure 10 or the cell 12) is X cm, and the opening area of ​​the plurality of cells 12 is Y cm. ２When Y / X is set as above, Y / X is preferably 30 or more, more preferably 40 or more, and even more preferably 50 or more. When Y / X is equal to or more than the above lower limit, the effect of suppressing an increase in pressure loss can be suitably obtained while ensuring the surface area of ​​the cells 12. The upper limit of Y / X is not particularly limited, but may be, for example, 850,000 or less, or 50,000 or less. The distance L is preferably 0.3 cm to 5 cm, more preferably 0.3 cm to 4 cm, and even more preferably 0.3 cm to 3 cm. The opening area Y of the plurality of cells 12 is preferably 5 cm ２ ~250,000 cm ２ , more preferably 10 cm ２ ~250,000 cm ２ , more preferably 100 cm ２ ~160,000 cm ２ In addition, the above-mentioned "opening area Y cm of the plurality of cells 12" ２ " means the total sum of the open areas of the plurality of cells 12 in a cross section perpendicular to the longitudinal direction of the honeycomb structure section 10.

[0019] Ceramics are representative examples of materials constituting the honeycomb structure member 10. From the viewpoints of heat resistance and corrosion resistance, preferred examples of ceramics include cordierite, mullite, alumina, zirconia, silicon nitride, silicon carbide, silicon-silicon carbide composite materials, silicon carbide-cordierite composite materials, spinel, lithium aluminum silicate, and aluminum titanate. For example, cordierite, which has a low thermal expansion coefficient, is preferably used from the viewpoint of reducing thermal stress. Furthermore, from the viewpoint of removing or utilizing the heat of reaction from an exothermic reaction, silicon-silicon carbide composite materials, which have high thermal conductivity, are preferably used. Materials constituting the honeycomb structure member 10 include materials other than ceramics, such as paper, paper coated with a protective layer, synthetic paper, and nonwoven fabric, from the viewpoint of facilitating the production of the honeycomb structure member 10. The materials constituting the honeycomb structure member 10 can be used alone or in combination.

[0020] When a functional material is supported on the honeycomb structure section 10, the functional material is typically supported on the partition walls 14 so as to be able to come into contact with a fluid passing through the cells 12. For example, the functional material can be supported on the partition walls 14 by forming a functional layer containing the functional material on the partition wall surface, or by forming the partition walls 14 using a material containing the functional material.

[0021] The functional material may be any material having an appropriate function depending on the purpose, and examples of the functional material include, but are not limited to, catalysts and adsorbents.

[0022] Specific examples of the catalyst include, but are not limited to, ammonia production catalysts (Fe, Co, Ni, Mo, Ru, etc.), ammonia decomposition catalysts (Ni, Ru, etc.), fuel reforming catalysts (Ge, Mo, Sn, Re, Ir, Pt, etc.), methanation catalysts (Fe, Co, Ni, Mo, Ru, Rh, etc.), methanol synthesis catalysts (Co, Cu, Mo, Rh, Pd, W, Re, Ir, Pt, alkali metal alkoxides, etc.), turquoise hydrogen production catalysts (Fe, Co, Ni, molybdenum carbide, etc.), volatile organic compound (VOC) combustion removal catalysts (Pd, Pt, manganese oxide, Co—Ce composite oxide, perovskite oxide, etc.), and methylcyclohexane synthesis catalysts by toluene hydrogenation (Ni, Ru, Rh, Ir, Pt, etc.).

[0023] Specific examples of adsorbents include, but are not limited to, carbon dioxide adsorbents (porous carbon materials, zeolites, metal organic frameworks, amine compounds, alkali metal carbonates, etc.), moisture absorbents (zeolites, silica gel, activated carbon, alumina, silica, low-crystalline clay, amorphous aluminum silicate complexes, etc.), and adsorbents for allergens, odor components, etc. (zeolites, alumina zinc silicate, silica gel, activated carbon, silica, amorphous aluminum silicate complexes, magnesia, zinc oxide, titanium oxide, metal organic frameworks, etc.).

[0024] A-2. Variation 1 The honeycomb structure may be a bonded body including a plurality of honeycomb structure sections arranged adjacent to each other in a direction perpendicular to the longitudinal direction and a bonding layer bonding the plurality of honeycomb structure sections together. When a plurality of honeycomb structure sections satisfying the above-mentioned cell density and Y / X relationship are bonded together, the occurrence of cracks can be more effectively prevented than when similar honeycomb structure sections are manufactured with a wider diameter.

[0025] FIG. 2 is a schematic perspective view showing the configuration of a honeycomb structure including four honeycomb structure parts and a bonding layer bonding these parts together.

[0026] The honeycomb structure 100B has four honeycomb structure members 10 and bonding layers 20 that bond the honeycomb structure members 10 together. Each honeycomb structure member 10 has an outer wall 16 and partition walls 14 that are disposed inside the outer wall 16 and extend from a first end face 10a to a second end face 10b to define a plurality of cells 12 that serve as fluid flow paths. The honeycomb structure members 10 preferably have the same length, and are bonded together so that the first end faces 10a are flush with each other and so that the second end faces 10b are flush with each other.

[0027] The honeycomb structure section 10 is as described above. The honeycomb structure sections 10 may have the same structure as each other or different structures. Specifically, in each honeycomb structure section 10, the arrangement, thickness, forming material, etc. of the partition walls 14 may be the same as each other or different from each other, and as a result, the cross-sectional shape, cell density, opening ratio, etc. of the cells 12 may be the same as each other or different from each other.

[0028] The bonding layer 20 can be formed of any appropriate bonding material. For example, a ceramic material with a solvent such as water added to form a paste can be used as the bonding material. The bonding layer 20 may contain the same ceramic as the outer wall 16 and / or the partition wall 14. The outer wall can also be formed by applying the bonding material to the periphery of multiple bonded honeycomb structure parts. The thickness of the bonding layer 20 can be, for example, 0.1 mm to 5 mm.

[0029] A-3. Modification 2 The honeycomb structure may be configured so that the honeycomb structure portion can be heated. For example, the honeycomb structure may have a magnetic material supported on the honeycomb structure and a coil wiring arranged to surround the outer periphery of the honeycomb structure. With this configuration, the honeycomb structure portion can be induction heated by passing an AC current through the coil wiring.

[0030] The magnetic body is preferably a magnetic material having a maximum magnetic permeability of 10,000 or more. Specific examples of the magnetic body include balance Fe-10% Si-5% Al, 49% Co-49% Fe-2% V, balance Fe-36% Ni, and balance Fe-45% Ni.

[0031] The magnetic material can be supported on the honeycomb structure by, for example, being disposed in some of the cells, or by forming partition walls or bonding layers containing magnetic material particles.

[0032] A-4. Manufacturing method of honeycomb structure The above honeycomb structure can be typically manufactured by a method including a molding step of extruding a molding material containing a ceramic raw material to obtain a honeycomb formed body, and a firing step of drying the honeycomb formed body and firing the resulting dried honeycomb body to obtain a honeycomb structure part.

[0033] In the molding process, typically, the molding material is extruded through a die having slits corresponding to the partition walls of the honeycomb structure to obtain a cylindrical honeycomb molded body having partition walls and outer walls that define cells that serve as fluid flow paths. By selecting an appropriate die and tool, the shape and density of each cell, as well as the shapes and thicknesses of the partition walls and outer walls, can be controlled. Furthermore, by employing a bracing structure, triangular cells, or other configurations, it is possible to achieve both favorable cell density and strength.

[0034] The molding material typically includes a ceramic raw material. As the ceramic raw material, powder of the above-mentioned ceramics, raw material powder that becomes the above-mentioned ceramics upon firing (for example, cordierite raw material), etc. can be used. The cordierite raw material is a raw material that becomes cordierite upon firing. The cordierite raw material is alumina (Al２ O ３ ) (including aluminum hydroxide converted to alumina): 30% to 45% by mass, magnesia (MgO): 11% to 17% by mass, and silica (SiO ２ It is preferable that the molding material has a chemical composition of 42% by mass to 57% by mass of ceramic raw materials. The molding material may further contain a binder, a pore-forming agent, a dispersant, water, an organic solvent, etc. In addition, by blending a functional material with the molding material, a honeycomb structure (specifically, partition walls and outer walls) made of a material containing the functional material can be obtained. The porosity and pore size of the honeycomb structure can be controlled by appropriately selecting the type and amount of the ceramic raw material, binder, pore-forming agent, and dispersant.

[0035] The honeycomb formed body is dried to obtain a dried honeycomb body. Before drying, the honeycomb formed body may be cut to a predetermined length.

[0036] Examples of drying methods for the honeycomb formed body include hot air drying, microwave drying, dielectric drying, reduced pressure drying, vacuum drying, and freeze drying. These may be used alone or in combination of two or more. 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.

[0037] The dried honeycomb body is fired to obtain a honeycomb structure part. Any appropriate firing conditions can be adopted. The firing temperature is, for example, 1400°C to 1500°C. The firing time is, for example, 20 hours to 80 hours. The firing may be carried out continuously or in multiple stages at different temperatures. When firing is carried out in multiple stages, the firing time is the sum of the firing times of each stage.

[0038] Before the dried honeycomb body is subjected to the firing treatment, the dried honeycomb body may be calcined. The calcination temperature may be determined, for example, depending on the combustion temperature of the organic matter contained in the dried honeycomb body. The calcination temperature is, for example, 200°C to 1000°C. The calcination time is, for example, 10 hours to 100 hours. Note that the calcination and firing may be carried out consecutively. Specifically, the calcination may be carried out during the temperature rise process of firing.

[0039] If necessary, the above-described manufacturing method may further include a functional material supporting step of supporting a functional material on the honeycomb structure section 10. The functional material supporting step may be preferably carried out after the firing step.

[0040] Any appropriate method can be used to support a functional material on a honeycomb structure. For example, a functional layer containing a functional material can be formed on the partition wall surface by a method including: immersing a honeycomb structure in a functional material dispersion containing a functional material, a binder, and a dispersion medium to form a coating layer on the partition wall surface; or flowing a functional material dispersion through the cells of the honeycomb structure to form a coating layer on the partition wall surface; and drying the coating layer. When immersing a honeycomb structure in a functional material dispersion, the functional material dispersion adhering to the end faces and outer wall surfaces of the honeycomb structure after immersion can be removed by blowing, wiping, or the like. The drying temperature can be, for example, 120°C to 600°C. The formation of the functional layer (i.e., the formation and drying of the coating layer) can be performed only once or can be repeated multiple times. By repeating the process multiple times, a desired amount of functional material can be preferably supported on the honeycomb structure.

[0041] Examples of the dispersion medium include water, organic solvents (e.g., toluene, xylene, ethanol, n-butanol, ethyl acetate, butyl acetate, terpineol, dihydroterpineol, Texanol, ethylene glycol monobutyl ether acetate, diethylene glycol monoethyl ether acetate, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether acetate, and diethylene glycol monobutyl ether), and mixtures thereof.

[0042] A honeycomb structure having a plurality of honeycomb structure parts bonded via a bonding layer can be produced by a method including the steps of: producing a plurality of honeycomb structure parts as described above; applying a bonding material to the outer walls of the honeycomb structure parts to form a coating layer; assembling the plurality of honeycomb structure parts via the coating layer to produce an assembly; and drying the assembly to form the coating layer as a bonding layer. There are no particular limitations on the bonding material, and any material for forming a bonding layer in a conventionally known honeycomb structure can be used.

[0043] B. Honeycomb Structure Stack A honeycomb structure stack according to an embodiment of the present invention includes a honeycomb structure portion having an outer wall and partition walls disposed inside the outer wall and defining a plurality of cells extending from an inflow end face to an outflow end face to serve as fluid flow paths, and includes two or more honeycomb structures disposed with at least a portion spaced apart so that the inflow end faces or the outflow end faces face each other, a fluid inflow channel forming a space on the inflow end face side of the honeycomb structure and communicating with the plurality of cells, and a fluid outflow channel forming a space on the outflow end face side of the honeycomb structure and communicating with the plurality of cells. In the honeycomb structure stack, typically, the cell density of the plurality of cells in the honeycomb structure portion is 186 cells / cm. ２ and the distance between the inlet end surface and the outlet end surface is X cm and the opening area of ​​the plurality of cells is Y cm ２ and satisfy the relationship Y / X≧30. Furthermore, the fluid inlet channel extends from one open end to the other closed end, and the fluid outlet channel extends from one open end to the other closed end. According to this configuration in which a plurality of honeycomb structures are stacked and arranged via the fluid inlet channel or the fluid outlet channel, even if the cell length of each honeycomb structure is short, it is possible to ensure a sufficient cell surface area for the entire stack, and space can be saved.

[0044] Each of the two or more honeycomb structures included in the honeycomb structure stack is typically the honeycomb structure described in Section A. Either the first end face or the second end face of the honeycomb structure described in Section A can be an inflow end face, and the other can be an outflow end face.

[0045] In one embodiment, all of the honeycomb structure portions of two or more honeycomb structures are formed from forming materials of the same composition and have partition walls of the same structure (resulting in the same cell density and opening ratio). In another embodiment, the honeycomb structure portions of two or more honeycomb structures may be formed from forming materials of different compositions and may have partition walls of different structures. In other words, the two or more honeycomb structures may be honeycomb structures having the same forming material composition and structure, or may be honeycomb structures having different forming material compositions and / or structures.

[0046] B-1. Overall configuration of honeycomb structure stack Fig. 3A is a schematic perspective view showing the configuration of a honeycomb structure stack according to one embodiment of the present invention, Fig. 3B is a schematic cross-sectional view (cross-sectional view taken along line A1-A1 in Fig. 3A) parallel to the direction in which fluid inlet channels of the honeycomb structure stack shown in Fig. 3A extend, and Fig. 3C is a schematic cross-sectional view (cross-sectional view taken along line A2-A2 in Fig. 3B) perpendicular to the direction in which fluid inlet channels of the honeycomb structure stack shown in Fig. 3A extend.

[0047] The honeycomb structure stack 200A has opposing fluid inlet end faces 200a and fluid outlet end faces 200b, and includes five honeycomb structures 100. Each honeycomb structure 100 has an inlet end face 100a and an outlet end face 100b, and is arranged spaced apart from one another with the inlet end faces 100a facing each other or with the outlet end faces 100b facing each other. The number of honeycomb structures included in the honeycomb structure stack is not limited to the illustrated example and can be appropriately set depending on the purpose. The number of honeycomb structures included in the honeycomb structure stack can be set to preferably 3 to 1,000, more preferably 5 to 500.

[0048] The five honeycomb structures 100 are housed in a cylindrical can 210. Specifically, a buffer member 220 is arranged along the inner periphery of the can 210. Positioning members 230, each having recesses corresponding to the length of the honeycomb structure portion, are arranged at predetermined intervals on both sides of the internal space of the buffer member 220. Plate-shaped holding members 240 are arranged on the top and bottom surfaces, respectively. Each of the five honeycomb structures 100 is fixed by fitting into the recesses of the positioning members 230. The can 210 and the holding members 240 may be formed, for example, of a metal material such as stainless steel or a ceramic material such as ferrite. The buffer member 220 may be formed, for example, of a ceramic fiber such as alumina fiber or mullite fiber. This configuration allows the honeycomb structures 100 to be suitably maintained in their housed state even when an external impact is applied. However, the configuration of the honeycomb structure stack is not limited to the illustrated example. For example, the buffer member, the positioning member, and / or the holding member may be omitted depending on the purpose.

[0049] The space between the opposing inlet end faces 100a constitutes a fluid inlet channel 120. Specifically, the fluid inlet channel 120 is defined by two inlet end faces 100a facing each other at a predetermined distance, or by the inlet end faces 100a and the holding member 240, and a connecting member connecting them. One end of the fluid inlet channel 120 is open, and the other end is closed by providing a sealing portion 142. In the illustrated example, positioning members 230 arranged on both side surfaces function as connecting members, but this configuration is not limited thereto. For example, sealing portions may be provided at both ends of the fluid inlet channel in a direction perpendicular to the extension direction, thereby serving as connecting members.

[0050] The space between the opposing outflow end faces 100b constitutes the fluid outflow channel 130. Specifically, the fluid outflow channel 130 is defined by two outflow end faces 100b facing each other at a predetermined distance, or by the outflow end face 100b and the holding member 240, and connecting members (in the illustrated example, positioning members 230 arranged on both side faces) that connect them. One end of the fluid outflow channel 130 is open, and the other end is closed by the provision of a sealing portion 144.

[0051] The fluid inlet channel 120 communicates with a plurality of cells 12 at the inlet end face 100a, and the fluid outlet channel 130 communicates with a plurality of cells 12 at the outlet end face 100b. With this configuration, fluid that flows into the fluid inlet channel 120 from an open end flows into the cells 12 from the inlet end face 100a, flows out from the outlet end face 100b, moves to the fluid outlet channel 130, and flows out from the open end. Furthermore, two adjacent honeycomb structures can share the fluid inlet channel 120 and / or the fluid outlet channel 130.

[0052] From the viewpoint of efficiently allowing a fluid to flow in and out of the honeycomb structure stack 200A, it is preferable that the fluid inlet channel 120 and the fluid outlet channel 130 extend in opposite directions. The angle formed between the extending direction of the fluid inlet channel 120 (in other words, the direction from the open-side end toward the closed-side end) and the extending direction of the fluid outlet channel 130 (in other words, the direction from the open-side end toward the closed-side end) is, for example, in the range of 180°±30°, and preferably in the range of 180°±25°.

[0053] The opening height T1 of the fluid inlet channel 120 and the opening height T2 of the fluid outlet channel 130 are each preferably 1 mm to 20 mm, and more preferably 5 mm to 18 mm. The opening height T1 of the fluid inlet channel 120 and the opening height T2 of the fluid outlet channel 130 may be the same or different. Furthermore, when there are multiple fluid inlet channels 120 and multiple fluid outlet channels 130, the opening heights of the fluid inlet channels 120 and the fluid outlet channels 130 may be the same or different.

[0054] The ratio (T1 / L or T2 / L) of the opening height T1 of the fluid inlet channel or the opening height T2 of the fluid outlet channel to the length L of the honeycomb structure 100 is preferably 1 or less, more preferably 0.7 or less, and even more preferably 0.5 or less. When the ratio is within the above range, a space-saving effect can be suitably obtained. The lower limit of the ratio can be, for example, 0.1 or more.

[0055] The length of each of the fluid inlet channel 120 and the fluid outlet channel 130 may be preferably 10 mm to 500 mm, more preferably 15 mm to 400 mm, and even more preferably 20 mm to 300 mm.

[0056] 3A to 3C, the honeycomb structures 100 are arranged parallel to each other so that the distance between the opposing inflow end faces 100a or outflow end faces 100b is constant, but each honeycomb structure 100 may be arranged obliquely relative to the adjacent honeycomb structure 100 so that the distance between the opposing inflow end faces 100a or outflow end faces 100b gradually increases or decreases. For example, two opposing honeycomb structures 100 may be arranged so that the inflow end faces 100a or the outflow end faces 100b are spaced apart from each other at one end and contact each other at the other end.

[0057] The angle formed by the extending direction of the inlet end face 100a or the extending direction of the outlet end face 100b facing each other may be, for example, in the range of 0°±30°, and preferably in the range of 0°±25°. When the angle is within the above range, a space-saving effect can be suitably obtained.

[0058] The honeycomb structure stack 200B shown in Figure 4 includes four honeycomb structures 100, and each honeycomb structure 100 is arranged obliquely so that the inflow end faces 100a facing each other form an angle θ1 greater than 0° and / or so that the outflow end faces 100b facing each other form an angle θ2 greater than 0°.

[0059] In the honeycomb structure stack 200B, two honeycomb structures 100 whose inflow end faces 100a face each other are arranged at an angle θ1 so as to be spaced apart at one end and contact each other at the other end, thereby forming a fluid inflow channel 120 whose one end is open and the other end is closed. Furthermore, two honeycomb structures 100 whose outflow end faces 100b face each other are arranged at an angle θ2 so as to be spaced apart at one end and contact each other at the other end, thereby forming a fluid outflow channel 130 whose one end is open and the other end is closed. The angles θ1 and θ2 may be the same or different.

[0060] In the honeycomb structure stack 200B, the four honeycomb structures 100 are housed in a cylindrical can body 210 in which buffer members 220, positioning members (not shown), and holding members 240 are arranged, similarly to the honeycomb structure stack 200A. Pressing members 250 for fixing both end portions of the honeycomb structure 100 are further arranged in the can body 210. The pressing members 250 may be plate-like members having openings in areas corresponding to the openings of the fluid inlet channels 120 or the openings of the fluid outlet channels 130. The pressing members 250 preferably fix the honeycomb structures 100 via the buffer members 220.

[0061] B-2. Manufacturing Method of Honeycomb Structure Stack A honeycomb structure stack according to an embodiment of the present invention can be manufactured by a method including, for example, accommodating a plurality of honeycomb structures in predetermined positions in a can body using buffer members, holding members, positioning members, pressing members, etc. The manufacturing method can further include, as necessary, providing plugging portions at one end of the space between adjacent honeycomb structures. Alternatively, for example, the positions of the honeycomb structures may be determined by temporarily fixing a plurality of honeycomb structures in predetermined positions in the can body and forming plugging portions. The plugging portions can be formed, for example, from the same material as the honeycomb structure portions.

[0062] There is no particular limitation on the method for accommodating the plurality of honeycomb structures 100 in predetermined positions of the can body 210, and any known method can be used. For example, in addition to fixing methods using fitting such as clearance fitting, interference fitting, and shrink fitting, brazing, welding, diffusion bonding, and the like can be used.

[0063] B-3. ​​Modification 1 Fig. 5 is a schematic cross-sectional view parallel to the extending direction of the fluid inlet channels of a honeycomb structure stack according to one embodiment of the present invention. A honeycomb structure stack 200C includes six honeycomb structures 100, and has a configuration in which the six honeycomb structures 100 are integrally formed via connecting portions 152 that alternately connect the honeycomb structures 100 adjacent to each other in the stacking direction at their opposing ends. Specifically, in the honeycomb structure stack 100C, the connecting portions 152 are formed of honeycomb structure portions.

[0064] The honeycomb structure stack 200C can be produced, for example, by a method including: fabricating the honeycomb structure described in Section A into a rectangular prism shape with a long cell length (specifically, fabricating a rectangular prism-shaped honeycomb structure similar to the honeycomb structure described in Section A except that Y / X exceeds 30); and forming slits 150 in the resulting honeycomb structure by alternately slitting opposing outer wall surfaces in a direction intersecting the cell extension direction. The slitting is performed so that a predetermined length of honeycomb structure portion remains in the slit direction. This leaves one end of the slit portion 150 open and the other end closed. The slit portion 150 can function as a fluid inlet channel 120 or a fluid outlet channel 130. The remaining honeycomb structure portion can also function as a connecting portion 152 connecting adjacent honeycomb structures 100 in the stacking direction and as a plug.

[0065] B-4. Modification 2 The honeycomb structure stack may be configured to be able to heat the honeycomb structure portion. For example, the honeycomb structure stack may have a magnetic material supported on one or more honeycomb structures and a coil wiring arranged to surround the outer periphery of the honeycomb structure stack (for example, the outer periphery or inner periphery of a can body). With this configuration, the honeycomb structure portion can be induction-heated by passing an AC current through the coil wiring. The magnetic material and the method for supporting it are as described above.

[0066] C. Reactor The honeycomb structure described in Section A and the honeycomb structure stack described in Section B can each be used as a reactor for carrying out various reactions. Here, the reactor does not necessarily need to support a functional material (e.g., a catalyst). For example, soot can be deposited inside a honeycomb structure that does not support a functional material, and then the soot can be burned (oxidized) by heating, thereby making it usable as a soot oxidation reactor.

[0067] When the honeycomb structure or the honeycomb structure stack itself does not have a configuration capable of heating the honeycomb structure part, the reactor may include, in addition to the honeycomb structure or the honeycomb structure stack, a heating device (for example, an electric heater) arranged in contact with or in the vicinity of the honeycomb structure or the honeycomb structure stack. Heating the honeycomb structure or the honeycomb structure stack can promote chemical reactions, adsorption / desorption reactions, etc.

[0068] The cell has a rectangular first end face and a second end face of 15 cm x 10 cm, a distance X between the first end face and the second end face is 0.5 cm, a cell density is 20,000 cpsi, and an opening area Y of the plurality of cells is 135 cm ２For a honeycomb structure A (Y / X = 270 cm) consisting of a honeycomb structure portion having a diameter of 1 / 2 mm, pseudo-structure 1 shown in FIGS. 3A-3C and pseudo-structure 2 shown in FIG. 4 were assumed as simple models of a honeycomb structure stack. Specifically, the following is described. As pseudo-structure 1, a structure was assumed in which a horizontally arranged honeycomb structure A and structural units U1 ( FIG. 6 ) each having a 2.5 mm-high plugging portion 142 provided along a long side of one end face and a 2.5 mm-high plugging portion 144 provided on the opposing long side of the other end face were stacked infinitely up and down with imaginary boundary planes B1 and B2 as symmetrical boundaries. In pseudo-structure 1, honeycomb structures A are stacked infinitely with 5 mm-high fluid inlet channels and 5 mm-high fluid outlet channels alternately interposed therebetween. As pseudo-structure 2, a structure was assumed in which structural units U2 (FIG. 7) consisting of honeycomb structures A arranged at an angle of 15° with respect to the horizontal plane were stacked infinitely one above the other with imaginary boundary planes B3 and B4 as symmetrical boundaries. In pseudo-structure 2, the long sides of the upper and lower honeycomb structures A are in contact with each other at imaginary boundary planes B3 and B4. Therefore, in pseudo-structure 2, honeycomb structures A are stacked infinitely with fluid inlet channels of decreasing diameter and fluid outlet channels of increasing diameter alternately interposed therebetween.

[0069] For the pseudo-structures 1 and 2, pressure loss calculations were performed when gas was introduced through the opening of the fluid inlet channel. The pressure loss calculations were performed with a processing flow rate of 0.0225 m ３ The experiment was carried out under two conditions: one where the gas flow velocity was 1 m / s (calculated assuming that the gas flows into the inlet end face of 150 mm x 100 mm at a flow velocity of 1 m / s), and the other where the flow velocity was 1 m / s.

[0070] As a control, a 15 cm x 15 cm square cell was used, which had a first end face and a second end face, a distance X between the first end face and the second end face was 10 cm, a cell density was 20,000 cpsi, and an opening area Y of the plurality of cells was 116 cm ２ Regarding honeycomb structure B (Y / X=11.6 cm) having a honeycomb structure part of the above, pressure loss was calculated when gas was flowed in from a direction perpendicular to the first end face under the above two conditions.

[0071] Based on the pressure losses calculated for each pseudo-structure and honeycomb structure B, the pressure loss reduction rate of the pseudo-structure [pressure loss reduction rate (%) = (pressure loss of honeycomb structure B - pressure loss of pseudo-structure) ÷ pressure loss of honeycomb structure B × 100] was calculated. The results are shown in Table 1.

[0072]

[0073] The present invention is not limited to the above-described embodiment, and various modifications are possible. For example, the configurations shown in the above-described embodiment can be replaced with configurations that are substantially the same as those shown in the above-described embodiment, that have the same effects, or that can achieve the same purpose.

[0074] The honeycomb structure and honeycomb structure stack according to the embodiment of the present invention can be suitably used as various reactors.

[0075] 10 honeycomb structure portion, 10a first end face, 10b second end face, 12 cell, 14 partition wall, 16 outer wall, 100 honeycomb structure, 100A-B honeycomb structure, 100a inlet end face, 100b outlet end face, 120 fluid inlet channel, 130 fluid outlet channel, 200A-C honeycomb structure stack.

Claims

1. A honeycomb structure part having an outer wall and partition walls disposed inside the outer wall, extending from a first end face to a second end face, and defining a plurality of cells that serve as fluid flow paths, wherein the cell density of the plurality of cells is 186 cells / cm ２ the distance between the first end surface and the second end surface is X cm and the opening area of ​​the plurality of cells is Y cm ２ and a honeycomb structure satisfying the relationship Y / X≧30.

2. A honeycomb structure including two or more honeycomb structures having an outer wall and partition walls arranged inside the outer wall and defining a plurality of cells extending from an inflow end face to an outflow end face to serve as a fluid flow path, the two or more honeycomb structures being arranged with at least a portion spaced apart so that the inflow end faces or the outflow end faces face each other; a fluid inflow channel forming a space on the inflow end face side of the honeycomb structure and communicating with the plurality of cells; and a fluid outflow channel forming a space on the outflow end face side of the honeycomb structure and communicating with the plurality of cells, wherein the cell density of the plurality of cells in the honeycomb structure is 186 cells / cm. ２ and the distance between the inlet end surface and the outlet end surface is X cm and the opening area of ​​the plurality of cells is Y cm ２ and satisfy a relationship of Y / X≧30, the fluid inlet channel extends from one open end to the other closed end, and the fluid outlet channel extends from one open end to the other closed end.

3. The honeycomb structure stack according to claim 2, wherein a plug is provided at the other end of the fluid inlet channel and / or the other end of the fluid outlet channel.

4. A honeycomb structure stack as described in claim 2, comprising two honeycomb structures arranged at a predetermined angle so that the inlet end faces face each other and are spaced apart at one end of the fluid inlet channel and in contact at the other end.

5. A honeycomb structure stack according to claim 2, comprising two honeycomb structures arranged at a predetermined angle so that the outflow end faces face each other and are spaced apart at one end of the fluid outflow path and in contact at the other end.

6. A honeycomb structure stack according to claim 2, wherein the angle formed by the extending directions of the opposing inflow end faces and / or the angle formed by the extending directions of the opposing outflow end faces is in the range of 0°±30°.

7. A honeycomb structure stack according to claim 2, wherein an angle formed between the extending direction of said fluid inlet channel and the extending direction of said fluid outlet channel is in the range of 180°±30°.

8. The honeycomb structure stack according to claim 2, wherein all of the honeycomb structure portions included in the two or more honeycomb structures are made of forming materials of the same composition and have partition walls of the same structure.

9. A honeycomb structure stack according to claim 2, wherein the honeycomb structure portions included in the two or more honeycomb structures are made of forming materials with different compositions from each other, or have partition walls with different structures from each other.

10. The honeycomb structure stack according to claim 2, wherein the honeycomb structure further includes a functional material supported on the partition walls.

11. The honeycomb structure stack according to claim 10, wherein the partition walls are formed of a material containing the functional material, or a functional layer containing the functional material is provided on a surface of the partition walls.

12. A reactor comprising the honeycomb structure of claim 1 or the honeycomb structure stack of claim 2.

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