JP2011194342A - Honeycomb structure and honeycomb catalytic substance - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a honeycomb structure which can support a large amount of catalyst inside a pore of a bulkhead, and a honeycomb substance which supports a large amount of catalyst and also, includes a bulkhead with low pressure loss.SOLUTION: This honeycomb structure 1 includes a plurality of cells 5 serving as a flow path for fluid which are compartmentalized by the porous bulkhead 3. The bulkhead 3 has a porosity of 60 to 75%, an average pore diameter of 15 to 60 μm and a thickness of 0.05 to 0.51 μm. In addition, the density of the cell 5 is 15 to 31 (cell/cm). Also, the honeycomb catalytic substance 30 supports a catalyst 21b inside the pore 11 of the bulkhead 3 of the honeycomb structure 1.

Description

  The present invention relates to a honeycomb structure and a honeycomb catalyst body used for exhaust gas purification of an internal combustion engine.

The exhaust gas from an internal combustion engine such as an automobile engine contains particulate matter, NO _x , CO, HC and the like. In order to collect particulate matter in exhaust gas, a honeycomb structure having porous partition walls is used. In addition, the honeycomb structure has a catalyst for these chemical reactions supported on partition walls in order to advance a chemical reaction in which NO _x , CO, and HC are oxidized or reduced to generate N ₂ , H ₂ O, and CO _2. It is also used as a honeycomb catalyst body (for example, Patent Document 1).

JP 2003-33664 A

  However, when the conventional honeycomb structure has partition walls with mechanical strength that can withstand practical use, and the catalyst is supported on the partition walls, a problem remains that the pressure loss of the honeycomb catalyst body increases. Yes.

  In view of the above problems, an object of the present invention is to provide a honeycomb structure capable of supporting a large amount of catalyst on partition walls, and a honeycomb catalyst body having partition walls supporting a large amount of catalyst and low pressure loss. There is to do.

  The present invention, which has been completed in order to solve the above problems, is the following honeycomb structure and honeycomb catalyst body.

[1] A plurality of cells serving as fluid flow paths partitioned by porous partition walls, the partition walls having a porosity of 60 to 75%, an average pore diameter of 15 to 60 μm, and a thickness of 0.05 to A honeycomb structure having a cell density of 0.51 mm and a density of 15 to 31 cells / cm ² .

[2] A honeycomb catalyst body according to [1], wherein a catalyst is supported in the pores of the partition walls.

[3] The honeycomb catalyst body according to [2], wherein the catalyst covers the inner walls of the pores of the partition walls with a thickness of 50 to 200 μm.

[4] The honeycomb catalyst body according to [2] or [3], wherein the cell has a shape of any one of a triangle, a quadrangle, a hexagon, and a circle in a cross section perpendicular to the extending direction of the cell. .

[5] The partition mainly includes at least one selected from the group consisting of a cordierite forming raw material, alumina, mullite, and lithium aluminosilicate (LAS), aluminum titanate, zirconia, silicon carbide, silicon nitride, activated carbon, and zeolite. The honeycomb catalyst body according to any one of [2] to [4], which is formed as a component.

  The honeycomb structure of the present invention can carry a large amount of catalyst on the partition walls. The honeycomb catalyst body of the present invention has partition walls that support a large amount of catalyst and have low pressure loss.

1 is a perspective view of an embodiment of a honeycomb structure of the present invention. It is a schematic diagram of the A-A 'cross section in FIG. It is the schematic diagram which expanded the inside of the frame B in FIG. It is a schematic diagram showing a mode that the catalyst was carry | supported by the partition shown in FIG.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. The present invention is not limited to the following embodiments, and changes, modifications, and improvements can be added without departing from the scope of the present invention.

1. Honeycomb structure:
1-1. Outline of the honeycomb structure of the present invention:
FIG. 1 is a perspective view of an embodiment of a honeycomb structure of the present invention. FIG. 2 is a schematic diagram of the AA ′ cross section in FIG. 1. Referring to FIGS. 1 and 2, the honeycomb structure 1 of the present invention has a plurality of cells 5 which are fluid flow paths partitioned by porous partition walls 3. In the honeycomb structure 1 of the present invention, the partition walls 3 have a porosity of 60 to 75%, an average pore diameter of 15 to 60 μm, and a thickness of 0.05 to 0.51 mm, and the density of the cells 5 is 15 to 15 mm. 31 (pieces / cm ² ).

  Referring to FIG. 1, the density of the cells 5 is the number of cells per square centimeter in a cross section perpendicular to the direction X in which the cells 5 extend.

3 is an enlarged schematic view of the inside of the frame B in FIG. 2, and FIG. 4 is a schematic view showing a state in which the catalyst is supported on the partition walls shown in FIG. Referring to these drawings, the honeycomb structure 1 according to the present invention is obtained when the partition wall 3 has a porosity of 60 to 75% and an average pore diameter of 15 to 60 μm, so that the catalyst 21 is supported on the partition wall 3. A large amount of the catalyst 21 can enter the pores 11 of the partition walls 3. Therefore, when the honeycomb structure 1 of the present invention is compared with the honeycomb structure having a partition wall porosity of less than 60%, when the same amount of the catalyst 21 is supported between the two, the honeycomb structure 1 of the present invention As much as 21 can enter the pores 11 of the partition wall 3, it is thinly overlapped on the outer surface 15 of the partition wall 3. Therefore, in the honeycomb structure 1 of the present invention, when the catalyst 21 is supported on the partition wall 3, the substantial partition wall is the sum of the thickness of the partition wall 3 and the thickness of the catalyst 21 overlapping the outer surface 15 of the partition wall 3. Therefore, it is possible to reduce the pressure loss when the fluid passes through the partition wall 3 (see the fluid Gin _in FIG. 4).

Further, since the density of the cells 5 is 15 to 31 (cells / cm ² ), the honeycomb structure 1 of the present invention has a partition wall with a high porosity as described above. High strength can be maintained.

In the honeycomb structure 1 of the present invention, since the partition wall 3 has a thickness of 0.05 mm or more, the mechanical strength is maintained high, and a sufficient amount of catalyst is provided in the pores 11 as the partition wall 3 is thick. 21 can be carried. In the honeycomb structure 1 of the present invention, when the partition wall 3 has a thickness of 0.51 mm or less, the pressure loss of the fluid passing through the partition wall 3 can be suppressed to a low level (see fluid G _{in in} FIG. 4).

1-2. Manufacturing method of honeycomb structure:
The honeycomb structure 1 of the present invention can be applied with an embodiment in which the partition walls 3 are made of a material mainly composed of ceramics. The honeycomb structure 1 of this embodiment is manufactured by producing a forming raw material in which a pore forming material such as graphite, starch, and a water-absorbing resin is contained in a ceramic raw material, and forming the forming raw material by extrusion molding or the like. be able to. As the pore-forming material of the adsorptive resin, water-absorbing resins such as starch, polyacrylic acid, polyvinyl alcohol, cellulose, and synthetic polymer can be used. In particular, the polyacrylic acid-based water-absorbing resin is preferably used as a pore-forming material because it has a high water absorption rate and can absorb water in a short period of time, and is less likely to change over time in the soil properties after mixing and kneading. . Furthermore, the water absorption capacity of these water absorbent resins is usually 10 to 20 times, preferably 12 to 20 times, and more preferably 15 to 20 times.

  In the case of the above production method, the pore former content is preferably 10 to 20 parts by mass with respect to 100 parts by mass of the ceramic raw material. The average particle diameter of the pore former is preferably 5 to 90 μm, and more preferably 10 to 80 μm. By using the forming raw material containing the pore former as described above, a honeycomb structure having partition walls having a porosity of 60 to 75% and an average pore diameter of 15 to 60 μm can be manufactured.

  In order to improve the extrudability of the forming raw material, the above-mentioned forming raw material can contain a surfactant such as ethylene glycol and fatty acid soap. In this case, it is preferable that content of surfactant is 3-20 mass parts with respect to 100 mass parts of ceramic raw materials.

  In preparing the forming raw materials, the materials other than the pore former and the surfactant, the types of ceramic raw materials, the composition of the forming raw materials, and the mixing method of the various raw materials are made into the desired shape. Conventional techniques relating to the production of a ceramic molded body obtained by molding can be appropriately employed.

  For example, regarding the embodiment in which the partition walls 3 are made of a material mainly composed of ceramics, the following manufacturing method can be applied to obtain a honeycomb structure having cordierite partition walls.

First, a forming raw material for forming a ceramic honeycomb-shaped formed body (hereinafter referred to as “ceramic honeycomb formed body”) is prepared. As a main raw material of the molding raw material, as a cordierite forming raw material excellent in heat resistance and low thermal expansion, kaolin (Al ₂ O ₃ 2SiO ₂ · 2H ₂ O) 0 to 20% by mass with an average particle diameter of 5 to 30 μm, average Talc (3MgO · 4SiO ₂ · H ₂ O) with a particle size of 15 to 30 μm 37 to 40% by mass, aluminum hydroxide with an average particle size of 1 to 30 μm 15 to 45% by mass, aluminum oxide with an average particle size of 1 to 30 μm 0 to 0% It is preferable to use a composition of 15% by mass of fused silica or quartz having an average particle size of 3 to 100 μm or quartz of 10 to 20% by mass as a main raw material.

  A desired additive may be added to the cordierite forming raw material which is the main raw material of the above-described forming raw material, if necessary. Examples of the additive include a binder, a dispersant for promoting dispersion in a liquid medium, and a pore former for forming pores.

  Examples of the binder include hydroxypropyl methylcellulose, methylcellulose, hydroxyethylcellulose, carboxymethylcellulose, polyvinyl alcohol, polyethylene terephthalate and the like. Examples of the dispersant include ethylene glycol, dextrin, fatty acid soap, polyalcohol and the like. Examples of the pore former include graphite, coke, wheat flour, starch, hollow or solid resin, fly ash balloon, silica gel, organic fiber, inorganic fiber, hollow fiber and the like. A binder can be used individually by 1 type or in combination of 2 or more types according to the objective.

  The forming raw material for forming the ceramic honeycomb formed body is usually charged with about 10 to 40 parts by weight of water with respect to 100 parts by weight of the mixed raw material powder of the main raw material and the additive added as necessary. Thereafter, the mixture is kneaded to obtain a plastic mixture.

  And this plastic mixture is shape | molded and a ceramic honeycomb molded object is obtained. Examples of the molding method include extrusion molding. This extrusion molding can be performed using a vacuum kneader, a ram type extrusion molding machine, a twin screw type continuous extrusion molding machine, or the like. In extrusion molding, when the shape of a cell in a cross section perpendicular to the cell extending direction is a triangle, a quadrangle, a hexagon, or a circle, a die provided with a slit corresponding to these shapes may be used.

  Next, the obtained ceramic honeycomb formed body is dried. As a method for drying the ceramic honeycomb formed body, various methods can be used. Examples thereof include hot air drying, microwave drying, dielectric drying, vacuum drying, vacuum drying, freeze drying, and far infrared drying. I can do it. In particular, it is preferable to dry by a method in which microwave drying and hot air drying or dielectric drying and hot air drying are combined. As drying conditions, it is preferable to dry at 30 to 150 ° C. for 1 minute to 2 hours. Thereafter, both end faces of the ceramic honeycomb molded body thus dried are cut into a predetermined length.

  The ceramic honeycomb formed body is fired to manufacture the ceramic honeycomb structure of the present embodiment. Examples of the method for firing the ceramic honeycomb formed body include a method in which the ceramic honeycomb formed body is fired by raising the temperature to 1350 to 1450 ° C. in an air atmosphere. As described above, a honeycomb structure having cordierite partition walls can be obtained.

2. Honeycomb catalyst body:
The honeycomb catalyst body of the present invention is characterized in that the catalyst is supported in the pores of the partition walls of the honeycomb structure. Referring to FIG. 4, the honeycomb catalyst body 30 of the present invention has a plurality of cells 5 that become the flow paths of the fluid G partitioned by the porous partition walls 3, and the partition walls 3 have a porosity of 60 to 60. 75%, average pore diameter of 15-60 μm, thickness of 0.05-0.51 mm, cell 5 density of 15-31 (cells / cm ² ), catalyst in pores 11 of partition walls 3 21b is carried. If the catalyst 21b is supported in the pores 11 of the partition walls 3, even if the catalyst 21a is supported on the outer surface of the partition walls 3, it belongs to the technical scope of the present invention. The catalyst 21 includes a substance that catalyzes an oxidation reaction or a reduction reaction using NO _x , CO, HC or the like as a reactant, such as used in exhaust gas purification [for example, platinum, NOX selective reduction SCR catalyst (metal-substituted zeolite, Vanadium, titania, tungsten oxide, silver, and alumina).

As described above, the honeycomb catalyst body 30 of the present invention allows a fluid to pass through the partition walls 3 because the pores 11 are not blocked by the catalyst 21 even when a large amount of the catalyst 21 is supported in the pores 11. (See the white arrow Gin _in FIG. 4). In addition, the honeycomb catalyst body 30 of the present invention can cause the components contained in the fluid to chemically react by the action of the catalyst 21 supported in the pores 11 even while the fluid passes through the partition walls 3.

Further, when the honeycomb catalyst body 30 of the present invention is used for purifying exhaust gas of an internal combustion engine, the particulate matter contained in the exhaust gas is filtered by the partition walls 3 and at the same time, the exhaust gas from which the particulate matter has been removed becomes pores. while passing through the 11, the supported catalyst 21 in the pores _11, NO x, CO, it becomes possible to oxidize or reduce the HC and the like. Therefore, by using the honeycomb catalyst body 30 of the present invention, a compact exhaust gas purification device that can perform filtration of particulate matter and oxidation reaction or reduction reaction of NO _x , CO, HC, etc. at the same place can be produced. .

  The honeycomb catalyst body of the present invention can be applied with the embodiments described below while having the above features.

Referring to FIG. 4, in the honeycomb catalyst body 30 of the present invention, it is preferable that the catalyst 21 covers the inner wall 13 of the pore 11 of the partition wall 3 with a thickness of 50 to 200 μm. In this embodiment, the mechanical strength of the partition walls 3 is increased by the catalyst 21 b that covers the inner walls 13 of the pores 11. Further, in this embodiment, in order to catalyst 21b covers the inner wall 13 of the pores 11 increases the frequency of contact between the fluid G _in the catalyst 21b passing through pores 11, passes through the pores 11 The catalytic reaction using the components contained _in the fluid Gin as a reactant is performed with high efficiency.

  Further, the honeycomb catalyst body 30 of the present invention can reduce the substantial partition wall thickness, which is the sum of the thickness of the partition walls 3 and the thickness of the catalyst 21 overlapping the outer surface 15 of the partition walls 3, The pressure loss when the fluid passes through the cell 5 and the partition wall 3 can be kept low. Therefore, when the honeycomb catalyst body 30 of the present invention is used for exhaust gas purification of an internal combustion engine such as an automobile engine, the fuel efficiency of the internal combustion engine such as the engine can be improved.

  Referring to FIG. 1, in the honeycomb catalyst body 30 of the present invention, the cell 5 has a shape of any one of a triangle, a square, a hexagon, and a circle in a cross section perpendicular to the cell extending direction X. It is preferable to have a rectangular shape or a hexagonal shape (in particular, a rectangular cell is shown in FIG. 1). In this embodiment, since the outer surface 15 of the partition wall 3 can be coated with the catalyst 21 with a uniform thickness, the pores 11 are less likely to be clogged by the catalyst 21.

  In the honeycomb catalyst body 30 of the present invention, the partition walls 3 are selected from the group consisting of a cordierite forming raw material, alumina, mullite and lithium aluminosilicate (LAS), aluminum titanate, zirconia, silicon carbide, silicon nitride, activated carbon, and zeolite. It is formed from the sintered compact which sintered the raw material which has 1 or more types as a main component. It is preferable that the partition 3 is formed from a sintered body by sintering a cordierite forming raw material. This is because cordierite ceramics have a small thermal expansion coefficient and are excellent in thermal shock resistance and mechanical strength. In addition, the raw material which has the said material as a main component here means that the said component occupies 80 mass% or more in the raw material of a sintered compact, and this component turns into a main crystal phase.

  EXAMPLES Hereinafter, although this invention is demonstrated further in detail based on an Example, this invention is not limited to these Examples.

(Examples 1 to 26, Comparative Examples 1 to 6)
(1) Honeycomb structure The honeycomb structures of Examples 1 to 26 and Comparative Examples 1 to 6 were produced as follows, and the average pore diameter, porosity, and isostatic fracture strength of the partition walls were measured.

(1-1) Production of honeycomb structure (Examples 1 to 26, Comparative Examples 1 to 6)
As a cordierite forming raw material (Cd), a material mixed so as to be 41% by mass of talc, 19% by mass of kaolin, 25% by mass of aluminum oxide, and 15% by mass of silica was used. 62 parts by mass of water (water ratio) as a dispersion medium and 4 parts by mass of methylcellulose as a binder are added to 100 parts by mass of the cordierite forming raw material, respectively, and a desired amount with respect to 100 parts by mass of the total mass of the cordierite forming raw material. A water-absorbent resin was added, mixed and kneaded to prepare a clay. As the water-absorbing resin, one having a water absorption ratio of 10.5 times and an average particle diameter after water absorption (average particle diameter after water absorption) of 32 μm was used. Mixing and kneading were performed with a sigma kneader, and further kneading with a vacuum kneader was performed to obtain a clay extruded into a cylindrical shape (diameter of bottom surface 300 mm).

  The obtained kneaded material was extruded using a ram-type extrusion molding machine to produce a honeycomb molded body having a cylindrical shape as a whole.

  Next, the obtained honeycomb formed body was dried by dielectric drying to obtain a dried honeycomb body.

  Next, the obtained honeycomb dried body was fired (maximum temperature 1350 to 1440 ° C.) to obtain a honeycomb structure. Regarding the honeycomb structures of Examples 1 to 26 and Comparative Examples 1 to 6, Table 1 shows cell density, partition wall thickness, and cell shape in a cross section perpendicular to the cell penetration direction.

(1-2) Average pore diameter Description of “JASO Automotive Standard Automotive Exhaust Gas Purifying Catalyst Ceramic Monolith Carrier Test Method 6.3 of M505-87” for honeycomb structures of Examples 1 to 26 and Comparative Examples 1 to 6 The average pore diameter of the partition walls was calculated from the value of the pore diameter measured using a mercury porosimeter (trade name: AutoPore III Model 9405, manufactured by Micromeritics). The results are shown in Table 1.

(1-3) Porosity For the honeycomb structures of Examples 1 to 26 and Comparative Examples 1 to 6, the porosity of the partition walls was measured using a mercury porosimeter in the same manner as the pore diameter. The results are shown in Table 1.

(1-4) Isostatic Fracture Strength About the honeycomb structures of Examples 1 to 26 and Comparative Examples 1 to 6, the isostatic fracture defined by the automobile standard (JASO standard) M505-87 issued by the Japan Society for Automotive Engineers It was measured based on the strength test. The isostatic fracture strength test is a test in which a ceramic honeycomb structure is placed in a rubber cylindrical container, covered with an aluminum plate, and isotropically pressurized and compressed in water. This is a test simulating the compression load when the outer peripheral surface is gripped. The isostatic fracture strength is indicated by a pressurized pressure value when the ceramic honeycomb structure is broken. The results are shown in Table 1.

(2) Honeycomb catalyst body A honeycomb catalyst body was prepared by supporting a catalyst on the honeycomb structures of Examples 1 to 26 and Comparative Examples 1 to 6, and the catalyst thickness, partition wall pressure loss, NO _x purification rate, Isostatic fracture strength was measured.

(2-1) Catalyst loading First, after the honeycomb structure was cut into a cylindrical shape with a bottom diameter of 2.54 cm and a central axial length of 5.08 cm, alumina sol, metal-supported zeolite and water were mixed. The catalyst coating solution was prepared by wet pulverization. The prepared honeycomb structure was impregnated once with this catalyst coating solution, and was evacuated to 0.8 MPa twice while being immersed in the catalyst solution. By performing evacuation, it becomes possible to first allow the catalyst to enter the pores. Thereafter, the catalyst was impregnated several times, blown off with air, and dried to prepare a honeycomb structure carrying a zeolite (honeycomb catalyst body).

(2-2) Measurement of catalyst thickness About the honeycomb catalyst bodies of Examples 1-26 and Comparative Examples 1-6, the micrographs of the cross section perpendicular to the central axis of the honeycomb catalyst bodies overlapped on the outer surface of the partition walls. The location where the thickness of the catalyst was the smallest was selected, and the thickness of the catalyst overlying the outer surface of the partition wall at this location was measured as the “catalyst thickness”. The catalyst thicknesses of the honeycomb catalyst bodies of Examples 1 to 26 and Comparative Examples 2 to 6 are shown in Table 2 as ratios to the catalyst thickness of the honeycomb catalyst bodies of Comparative Example 1. In the honeycomb catalyst bodies of Examples 1 to 26 and Comparative Examples 1 to 6, when the same amount of catalyst is supported, the honeycomb catalyst body having a higher porosity has more catalyst entering the pores of the partition walls. It was found that the thickness of the catalyst overlying the outer surface of the partition wall (catalyst thickness) was reduced.

(2-3) Pressure loss About the honeycomb catalyst body of Examples 1-26 and Comparative Examples 1-6, air was distribute | circulated by the flow rate of 0.5 m < ³ > / min on room temperature conditions, and the pressure loss was measured. The results are shown in Table 2.

(2-6) Measurement of catalyst clogging The honeycomb catalyst carriers of Examples 1 to 26 and Comparative Examples 1 to 6 were irradiated with light from one end face, and a cell through which light did not pass to the other end face was detected. For cells through which light does not pass, a needle was inserted into the cell from one end face, and the number of cells that could not pass the needle to the other end face was counted. When the number of cells through which the needle could not pass from one end face to the other end face was 0.5% or more of the total number of cells, the catalyst clogging was judged as “present”. The results are shown in Table 2.

(2-5) NO _x purification rate The test gas was allowed to flow through the honeycomb catalyst bodies of Examples 1 to 26 and Comparative Examples 1 to 6, and the NO _x amount of the exhaust gas discharged from the honeycomb catalyst bodies was analyzed with a gas analyzer. did. The temperature of the test gas flowing into the honeycomb catalyst body was 200 ° C. The honeycomb catalyst body used in the test was cut into a cylindrical shape having a bottom diameter of 2.54 cm and a central axis direction length of 5.08 cm. The temperature of the honeycomb catalyst body and the test gas can be adjusted by a heater. An infrared image furnace was used as the heater. As a test gas, a gas in which 5% by volume of carbon dioxide, 14% by volume of oxygen, 350 ppm of nitrogen monoxide (volume basis), 350 ppm of ammonia (volume basis) and 10% by volume of water were mixed with nitrogen. The test gas was obtained by separately preparing water and a mixed gas obtained by mixing other gases, and mixing them in a pipe when performing the test. As the gas analyzer, “MEXA9100EGR manufactured by HORIBA” was used. The flux when the test gas flows into the honeycomb catalyst body was set to 50000 (time- ¹ ). Table 2, Examples 1 to 26, relates to _the NO _x purification rate of the honeycomb catalyst body of Comparative Example 2-6 are shown as the ratio purification rate of the NO _X Comparative Example 1 (NO _X purification rate) (%). _The NO _x purification rate, the amount of NO _x test gas was flowed into the honeycomb catalyst body, the value obtained by subtracting the amount of NO _x emissions from the honeycomb catalyst body, the gas testing were introduced into the honeycomb catalyst body It is a value obtained by dividing by the amount of NO _{X and} multiplying by 100 (percentage ratio). In the honeycomb catalyst bodies of Examples 1 to 26, the catalyst is also supported in the pores, and the gas contacts the catalyst also in the pores in addition to the outer surface of the partition walls. For this reason, in the honeycomb catalyst bodies of Examples 1 to 26, the contact area between the catalyst and the gas was increased, so that the NO _x purification rate was higher than that of the honeycomb catalyst bodies of Comparative Examples 1 to 6.

(2-6) Isostatic Fracture Strength An isostatic fracture strength test was performed on the honeycomb catalyst bodies of Examples 1 to 26 and Comparative Examples 1 to 6 by the same method as (1-4) above. The results are shown in Table 1. It has been found that the honeycomb catalyst bodies of Examples 1 to 26 increase the isostatic fracture strength by supporting the catalyst. For example, Example 2 and Comparative Example 4 had the same isostatic fracture strength (2.1 MPa) in the honeycomb structure before supporting the catalyst. Regarding the isostatic fracture strength after catalyst loading, the honeycomb catalyst body of Example 2 was 3.3 PMa, and the honeycomb catalyst of Comparative Example 4 was 2.7 MPa. In the honeycomb catalyst body of Example 2, since the inner walls of the pores of the partition walls are coated with the catalyst, it is considered that the strength of the honeycomb catalyst body is increased as compared with the honeycomb catalyst body of Comparative Example 4.

  The present invention can be used as a honeycomb structure and a honeycomb catalyst body used for exhaust gas purification of an internal combustion engine.

1: honeycomb structure, 3: partition wall, 5: cell, 7: end face, 11: pore, 13: inner wall, 15: outer surface, 21, 21a, 21b: catalyst, 30: honeycomb catalyst body.

Claims (5)

Having a plurality of cells serving as fluid flow paths partitioned by a porous partition;
The partition wall has a porosity of 60 to 75%, an average pore diameter of 15 to 60 μm, and a thickness of 0.05 to 0.51 mm.
A honeycomb structure having a cell density of 15 to 31 (cells / cm ² ). In the honeycomb structure according to claim 1,
A honeycomb catalyst body in which a catalyst is supported in the pores of the partition walls.   The honeycomb catalyst body according to claim 2, wherein the catalyst covers the inner walls of the pores of the partition walls with a thickness of 50 to 200 µm.   The honeycomb catalyst body according to claim 2 or 3, wherein the cell has a shape of any one of a triangle, a quadrangle, a hexagon, and a circle in a cross section perpendicular to a direction in which the cell extends.   The partition is composed mainly of at least one selected from the group consisting of a cordierite forming raw material, alumina, mullite and lithium aluminosilicate (LAS), aluminum titanate, zirconia, silicon carbide, silicon nitride, activated carbon and zeolite. The honeycomb catalyst body according to any one of claims 2 to 4, wherein

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