JP5649778B2 - Honeycomb structure and honeycomb catalyst body - Google Patents

Description

The present invention relates to a honeycomb structure and a catalyst body. More specifically, by supporting the catalyst, carbon monoxide (CO), hydrocarbon (HC) contained in exhaust gas discharged from automobiles, construction machinery, industrial stationary engines, and combustion equipment, etc. A honeycomb structure capable of efficiently purifying harmful substances of nitrogen oxide (NO _x ) and effectively suppressing an increase in pressure loss, and a catalyst supported on the honeycomb structure The present invention relates to a honeycomb catalyst body.

Currently, a honeycomb catalyst body in which a catalyst is supported on a honeycomb structure is used to purify exhaust gas discharged from various engines or the like (see, for example, Patent Document 1). In such a honeycomb catalyst body, fluid (exhaust gas) flows into each cell from the end face on the inflow side, and carbon monoxide (CO), hydrocarbon (HC), nitrogen oxide (NO _X ) contained in the exhaust gas. And other harmful substances are purified with a catalyst.

  Conventionally, a honeycomb structure used for such a honeycomb catalyst body increases the cell density, increases the geometric area on which the catalyst is supported, and improves the exhaust gas purification performance. It was made to increase the contact efficiency.

Japanese Patent Laid-Open No. 07-00766

  However, in the conventional honeycomb structure and honeycomb catalyst body, if the cell density of the honeycomb structure is increased in order to improve the purification performance, the pressure loss when the exhaust gas passes through the cell increases. On the other hand, if it is intended to suppress the increase in pressure loss by thinning the partition walls of the honeycomb structure, the contact efficiency between the exhaust gas and the catalyst is lowered, and the exhaust gas purification performance is lowered.

  Thus, in the conventional honeycomb structure and honeycomb catalyst body, there is a tradeoff between improving the purification performance and reducing the pressure loss, and it is extremely difficult to achieve both. There was a problem.

  The present invention has been made in view of such problems of the prior art, and by carrying a catalyst, it is possible to efficiently purify harmful substances contained in exhaust gas, and pressure loss Is provided, and a honeycomb catalyst body in which a catalyst is supported on the honeycomb structure is provided.

  In order to solve the above-described problems, the present invention provides the following honeycomb structure and honeycomb catalyst body.

[1] A columnar honeycomb structure portion having a porous partition wall, wherein a plurality of cells serving as a fluid flow path penetrating from the end surface on the inflow side to the end surface on the outflow side are formed by the partition wall, The partition walls have a porosity of 50 to 80% and an average pore diameter of 13 to 70 μm, and some of the plurality of cells have an opening at the end on the inflow side and an outflow A first cell in which an opening area reducing member is disposed so as to block a part of the opening at the opening on the side, and the remaining cell is a first cell having openings at both ends. Two cells, wherein the first cells and the second cells are alternately arranged, and the area of the first cells is the area of the second cells in a cross section perpendicular to the flow direction of the cells. The outflow of the first cell in a cross section that is larger and perpendicular to the cell flow direction. The area of the portion where the opening area reduction member at the opening end is not arranged state, and are more than 40% of the area of the second cell, in a cross section perpendicular to the flow path direction of the cell, the first The opening area of the opening area reducing member, which is the area of the opening of the cell at the outflow side end portion where the opening area reducing member is not disposed, is 5 to 5 of the opening area of the first cell. 80% der Ru honeycomb structure.
[ 2 ] The honeycomb structure according to [1] , wherein the opening area reducing member is made of a porous body having a porosity of 20 to 80%.
[ 3 ] A plurality of honeycomb structures according to [1] or [ 2 ] are provided as honeycomb segments, and the plurality of honeycomb segments are arranged adjacent to each other such that their side surfaces face each other, A bonded honeycomb structure in which opposing side surfaces are bonded together by a bonded portion.
[ 4 ] A honeycomb structure according to [1] or [ 2 ] , and a catalyst supported on the inner surface of the pores of the partition walls of the honeycomb structure and supported on the surface of the partition walls, A honeycomb catalyst body having a supported amount of 100 to 250 g / L.
[ 5 ] A bonded honeycomb structure according to [ 3 ], and a catalyst supported on the inner surface of the pores of the partition walls of the bonded honeycomb structure and a catalyst supported on the partition wall surfaces, A honeycomb catalyst body having a supported amount of 100 to 250 g / L.

  The honeycomb structure and the honeycomb catalyst body of the present invention include a honeycomb structure having a honeycomb structure portion having a porous partition wall having a specific porosity and an average pore diameter. Since the area of the opening is reduced by the opening area reducing member, a part of the fluid that has flowed into the first cell is transmitted through the partition wall that defines the first cell, and the inside of the adjacent second cell. The harmful substances contained in the exhaust gas can be purified efficiently.

  In the honeycomb structure and the honeycomb catalyst body of the present invention, the porosity and average pore diameter of the partition walls are in a specific range, and the area of the opening on the outflow side is reduced in the first cell. However, as described above, the exhaust gas purification efficiency is improved because a part of the fluid can flow out from the reduced opening (that is, the opening is not completely sealed). In addition, the increase in pressure loss can be effectively suppressed or the pressure loss can be reduced.

  That is, the honeycomb structure and the honeycomb catalyst body of the present invention can simultaneously solve the problems that are difficult to achieve with the conventional techniques, such as improving the purification efficiency of exhaust gas and suppressing the increase in pressure loss. Further, the amount of the supported catalyst can be reduced by improving the purification efficiency.

  Furthermore, the honeycomb structure and the honeycomb catalyst body of the present invention improve the purification efficiency and reduce the pressure loss because the area of the first cell is larger than the area of the second cell in the cross section perpendicular to the cell flow direction. There is an effect of suppressing the increase.

  BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the best mode for carrying out the present invention will be specifically described. However, the present invention is not limited to the following embodiment, and is within the scope of the gist of the present invention. Based on this knowledge, it should be understood that design changes, improvements, etc. can be made as appropriate.

[1] Honeycomb structure:
As shown in FIGS. 1 to 3, the honeycomb structure 100 of the present embodiment has a porous partition wall 1, and the fluid flow that penetrates from the inflow side end surface 2 to the outflow side end surface 3 by the partition wall 1. A plurality of cells 4 serving as paths are provided with columnar honeycomb structures 5, and the partition wall 1 has a porosity of 50 to 80% and an average pore diameter of 13 to 70 μm. In some of the cells 4, an opening at the end on the inflow side is opened, and an opening area reducing member 6 is disposed at the opening at the end on the outflow side so as to block a part of the opening. The first cell 4a, the remaining cell 4 is a second cell 4b having openings at both ends, and the first cell 4a and the second cell 4b are alternately arranged, In the cross section orthogonal to the cell flow direction, the area of the first cell is larger than the area of the second cell, In the cross section orthogonal to the road direction, the area of the first cell 4a where the opening area reducing member is not provided in the opening at the outflow side end is 40% or more of the area of the second cell 4b. . The opening area reducing member 6 disposed in the first cell 4a is formed with a through hole 7 penetrating in the cell flow path direction. The “portion where the opening area reducing member in the opening at the outflow side end of the first cell 4 a is not disposed” refers to the through hole 7. Here, FIG. 1 is a perspective view schematically showing one embodiment of the honeycomb structure of the present invention, and FIG. 2 is an outflow schematically showing one embodiment of the honeycomb structure of the present invention. FIG. 3 is a plan view seen from the side end face side, and FIG. 3 is a schematic diagram showing a cross section along line AA ′ of FIG. 2.

The honeycomb structure 100 of the present embodiment can be suitably used as a catalyst carrier of a honeycomb catalyst body for purifying exhaust gas discharged from various engines or the like. More specifically, for example, a honeycomb catalyst body is produced by supporting a catalyst on the inner surface of the pores of the partition walls and the partition surface, and the obtained honeycomb catalyst body is disposed inside the exhaust gas exhaust system, A fluid (exhaust gas) flows into each cell from the end surface on the inflow side, and the inflowed exhaust gas permeates through the partition wall, thereby allowing carbon monoxide (CO), hydrocarbon (HC), nitrogen oxide (NO _X). ) And other harmful substances are purified with a catalyst.

  In the honeycomb structure 100 of the present embodiment, the partition walls 1 have a porosity of 50 to 80% and an average pore diameter of 13 to 70 μm, and the porosity is higher than that of the honeycomb structure used in the conventional honeycomb catalyst body. The partition wall 1 is formed of a porous body that is high and has a large average pore diameter. For this reason, when a catalyst is supported on a honeycomb structure and used as a honeycomb catalyst body, an increase in pressure loss can be effectively suppressed.

  In this specification, “porosity” refers to a value measured by a mercury porosimeter (mercury intrusion method). The “average pore diameter” is measured by a mercury porosimeter (mercury intrusion method), and the cumulative volume of mercury injected into the porous substrate (ie, the partition wall) is the total fineness of the porous substrate. The pore diameter calculated from the pressure when the pore volume is 50%.

  Furthermore, the honeycomb structure 100 of the present embodiment flows into the first cell 4a because the area of the cell opening on the end surface 3 on the outflow side of the first cell 4a is reduced by the opening area reducing member 6. A part of the fluid can be permeated through the partition wall 1 that forms the first cell 4a and actively flow out into the adjacent second cell 4b, and the harmful substances contained in the exhaust gas can be efficiently discharged. Can be purified.

  Furthermore, in the honeycomb structure 100 of the present embodiment, the opening area of the opening of the first cell 4a (the area in the cross section perpendicular to the flow path direction of the cell) is reduced by the opening area reducing member 6. Since a part of the fluid can flow out from the reduced opening (that is, the opening of the first cell 4a is not completely sealed), the exhaust gas purification efficiency is improved as described above. While improving, the increase in pressure loss can be suppressed effectively or pressure loss can be reduced.

  Further, in the second cell 4b, the fluid passing through the inside of the second cell 4b is agitated by the fluid flowing through the partition wall 1 from the adjacent first cell 4a, so that the second cell 4b is stirred. The contact efficiency with the catalyst supported on the surface of the partition wall 1 partitioning 4b is improved, and the purification performance can be improved more effectively.

  Furthermore, in the honeycomb structure 100 of the present embodiment, the area of the first cell 4a is larger than the area of the second cell 4b in the cross section orthogonal to the cell flow direction, so that the purification efficiency is improved and the increase in pressure loss is suppressed. There is an effect.

  The honeycomb structure 100 of the present embodiment has a porous partition wall 1, and a plurality of cells 4 serving as fluid flow paths that penetrate from the end surface 2 on the inflow side to the end surface 3 on the outflow side are partitioned by the partition wall 1. The formed columnar honeycomb structure 5 is provided. Note that the honeycomb structure portion 5 constituting the honeycomb structure 100 of the present embodiment has an outer peripheral wall 11 disposed so as to surround the outer periphery of the partition wall 1 defining the cells 4.

  As described above, this partition wall has a porosity of 50 to 80% and an average pore diameter of 13 to 70 μm. The lower limit value of the partition wall porosity is preferably 55%, and preferably 60%. Is more preferable, and it is especially preferable that it is 65%. Further, the upper limit value of the porosity of the partition walls is preferably 80%, more preferably 75%, and particularly preferably 70%. With this configuration, the exhaust gas purification efficiency can be improved satisfactorily, the increase in pressure loss can be effectively suppressed, and further the pressure loss can be reduced.

  In addition, when the porosity of the partition is less than 50%, the porosity of the partition is too low, the pore surface area of the partition is reduced, the effect of improving the purification efficiency, and the effect of suppressing the increase in pressure loss It becomes impossible to achieve both. In particular, the exhaust gas purification efficiency is significantly reduced. On the other hand, when the porosity of the partition walls exceeds 80%, the amount (flow rate) of the exhaust gas that permeates the partition walls increases and the exhaust gas purification efficiency is improved, but the mechanical strength of the honeycomb structure is significantly reduced. , Damage and the like are likely to occur, making it difficult to use as a catalyst carrier.

  Conventionally, in a honeycomb structure used as a catalyst carrier, when the mechanical strength is significantly reduced, a large amount (excess) of a catalyst containing a noble metal is supported to increase the mechanical strength of the honeycomb catalyst body. In some cases, the precious metals contained in the catalyst described above are relatively expensive, and there is a problem that the manufacturing cost of the honeycomb catalyst body increases with an increase in the amount of the catalyst used. The honeycomb structure of the present embodiment has a mechanical strength that can withstand use as a catalyst carrier in a necessary and sufficient amount of catalyst supported.

  Moreover, the average pore diameter of the partition walls of the honeycomb structure part constituting the honeycomb structure is 13 to 70 μm, and preferably 13 to 60 μm. The lower limit of the average pore diameter is more preferably 15 μm or more, particularly preferably 18 μm or more, and the upper limit is further preferably 50 μm or less, and particularly preferably 40 μm or less. With this configuration, the exhaust gas purification efficiency can be improved satisfactorily, the increase in pressure loss can be effectively suppressed, and further the pressure loss can be reduced.

  When the average pore diameter of the partition walls is less than 13 μm, when the catalyst is supported on the inner surface of the partition wall pores and used as a honeycomb catalyst body, the pores are blocked, and the exhaust gas from the inner surface of the pores is blocked. Purification is not performed, and purification efficiency is significantly reduced. On the other hand, if the average pore diameter of the partition walls exceeds 70 μm, the total inner surface area of the partition wall pores decreases, and the exhaust gas purification efficiency decreases.

Cell density of the honeycomb structure of the present embodiment is preferably from 31 to 93 cells ^/ cm 2 ^{(200~600cpsi),} more preferably from 31 to 47 cells ^/ cm 2 ^{(200~300cpsi).} When the cell density is less than 31 cells / cm ² , the contact efficiency with the exhaust gas is lowered, and the purification efficiency may be lowered. When the cell density is more than 93 cells / cm ² , the pressure loss is increased. Sometimes. “Cpsi” is an abbreviation for “cells per square inch”, and is a unit representing the number of cells per square inch.

  Moreover, it is preferable that the thickness of a partition is 15-43 mm, and it is still more preferable that it is 20-30 mm. If the partition wall thickness is less than 15 mm, the strength may be insufficient and thermal shock resistance may decrease, and if it exceeds 43 mm, pressure loss may increase.

  The shape of the cross section perpendicular to the central axis of the honeycomb structure of the present embodiment, that is, the shape of the outer peripheral wall arranged so as to surround the partition wall is not particularly limited, but for example, a circle, an ellipse, an ellipse, a trapezoid , Triangles, squares, hexagons, other polygons, or left-right asymmetrical shapes. Among these, a circle, an ellipse, an ellipse, and a quadrangle are preferable.

  As a material constituting the partition walls of the honeycomb structure of the present embodiment, a material mainly composed of ceramics can be given as a suitable example. Preferred examples of ceramics include silicon carbide, cordierite, aluminum titanate, sialon, mullite, silicon nitride, zirconium phosphate, zirconia, titania, alumina, silica, or a combination thereof. In particular, ceramics such as silicon carbide, cordierite, mullite, silicon nitride, and alumina are preferable from the viewpoint of alkali resistance. Among these, oxide-based ceramics are preferable because of their low cost.

  Note that the outer peripheral wall disposed so as to surround the partition walls may be a molded integrated wall that is formed integrally with the honeycomb structure portion at the time of forming the honeycomb structure portion, or a honeycomb structure portion having a wall on the outer periphery thereof. Alternatively, the outer peripheral wall of the honeycomb structure portion may be ground into a predetermined shape and the outer peripheral wall may be formed of cement or the like. Such an outer peripheral wall can be formed using the material similar to the material which comprises the partition mentioned above, for example.

  In the honeycomb structure of the present embodiment, a plurality of cells penetrating from the end surface on the inflow side to the end surface on the outflow side are partitioned by the porous partition walls. This cell serves as a flow path for fluid, that is, exhaust gas, and a part of the exhaust gas flowing in from the end surface on the inflow side passes through the partition wall that partitions the cell and flows out into the adjacent cell. In addition, harmful substances are purified by the inner surface of the pores of the partition walls and the catalyst supported on the partition surface, and the resulting purified gas can be discharged from the end face on the outflow side.

  In the honeycomb structure of the present embodiment, as shown in FIGS. 1 to 3, some of the cells 4 in the plurality of cells 4 are open at the end on the inflow side and end at the outflow side. Is the first cell 4a in which the opening area reducing member 6 is disposed so as to block a part of the opening, and the remaining cell 4 is the second cell in which the opening at both ends is opened. This is a cell 4b, in which the first cells 4a and the second cells 4b are alternately arranged.

  The opening area reducing member 6 is preferably made of a porous body having a porosity of 20 to 80%. With this configuration, the exhaust gas can permeate through the opening area reducing member 6, so that the exhaust gas can also be purified by the opening area reducing member 6. If the porosity is less than 20%, the surface area of the pores may not be fully utilized. On the other hand, if the porosity exceeds 80%, the mechanical strength of the opening area reducing member is significantly reduced. May cause damage or the like. The porosity of the plugged portion is more preferably 40 to 80%, and particularly preferably 65 to 75%.

  The opening area reducing member 6 has a length from the end face (outlet end face) in the outflow side opening to the opposite end face in the cell flow path direction, that is, the arrangement depth of the opening area reducing member 6 is 0. It is preferably 3 to 10 mm, and more preferably 0.5 to 5 mm. For example, if the above-mentioned arrangement depth is less than 0.3 mm, the mechanical strength of the plugged portion is reduced, and the bonding force between the plugged portion and the partition wall cannot be sufficiently obtained, and the exhaust gas The plugging portion may be easily damaged by pressure or vibration from the outside. On the other hand, if it exceeds 10 mm, the effective area of the partition wall through which the exhaust gas permeates decreases, and sufficient purification efficiency may not be obtained.

  As the material constituting the opening area reducing member 6, those mentioned as the material of the partition walls constituting the honeycomb structure portion can be preferably used, and the material of the partition walls is more preferably the same.

  In the honeycomb structure of the present embodiment, the opening area of the opening area reducing member 6 disposed in the first cell 4a is the opening area of the first cell 4b in the cross section orthogonal to the flow path direction of the cell 4. 5 to 95%, preferably 20 to 75%. If it is less than 5%, the pressure loss may increase, and if it is more than 95%, the purification efficiency may not be improved. The opening area of the opening area reducing member 6 is an area (opening area) in a cross section perpendicular to the cell flow path direction of the through hole 7 formed in the opening area reducing member 6. The opening area of the opening area reducing member 6 does not need to be constant in the flow path direction. If the opening area is not constant, the opening area is the largest opening area in the portion where the opening area reducing member is disposed. It shall refer to the opening area of the portion that has become smaller. Furthermore, the opening area of each of the first cells is preferably uniform, but it may not be uniform. For example, the central part where the exhaust gas flow rate is large reduces the opening area, and the outer peripheral part where the exhaust gas flow rate is small is Increasing the opening area is one of the preferred embodiments.

  In the honeycomb structure of the present embodiment, in the cross section orthogonal to the cell flow direction, the area of the portion of the first cell where the opening area reducing member is not provided in the opening at the outflow side end (disconnection) (Area) is formed to be 40% or more of the area (cross-sectional area) of the second cell. In the cross section perpendicular to the cell flow path direction, the area (cross-sectional area) of the first cell in the opening portion at the outflow side end portion where the opening area reducing member is not disposed is the area of the second cell. It is preferably formed to be 70% or more of (cross-sectional area), and more preferably larger than the area (cross-sectional area) of the second cell. In the cross section perpendicular to the cell flow path direction, the area (cross-sectional area) of the first cell in the opening portion at the outflow side end portion where the opening area reducing member is not disposed is the area of the second cell. Since it is formed to be 40% or more of the (cross-sectional area), resistance is applied to the gas flow path, and there is a remarkable effect that the purification rate is improved by gas flowing into the second cell.

  In the honeycomb structure of the present embodiment, the area of the first cell is larger than the area of the second cell in the cross section perpendicular to the cell flow direction, but the second cell The cross-sectional area of the cell is preferably 40 to 85%, more preferably 50 to 70% with respect to the cross-sectional area of the first cell. When the cross-sectional area of the second cell is smaller than 40% of the cross-sectional area of the first cell, the pressure loss may increase, and the cross-sectional area of the second cell is more than 85% of the cross-sectional area of the first cell. If it is larger, the cross-sectional area of the second cell becomes larger, so that the amount of gas passing to the first cell may be reduced and the purification efficiency may be lowered.

  As shown in FIG. 6, in the honeycomb structure of the present embodiment, a line located at an equal distance from both the adjacent first cell 52 and the second cell 53 is a center line 51 a, and the “adjacent first "The other second cell 55" adjacent to the first cell 52 in the cell 52 and the second cell 53 of the first cell 52 and the second cell 55 adjacent to the second cell 55 When a line located equidistant from both of the “second cell 53” adjacent to the second cell 53 of the cell 52 and the second cell 53 ”is the center line 51b, The distance D between the line 51a and the center line 51b (deviation width between the first cell and the second cell) D is equal to the distance E between the center points of the adjacent first cell and the second cell. It is preferable that it is 5.5 to 8.5%. If the shift width between the first cell and the second cell is smaller than 5.5%, the difference in cross-sectional area between the first cell and the second cell may be small, and the pressure loss reduction effect may be small. If it is larger than%, the sectional area of the second cell is large, and the purification efficiency may be reduced. FIG. 6 is a schematic diagram showing the cell arrangement (arrangement of the first cell and the second cell) in a cross section perpendicular to the cell flow direction in one embodiment of the honeycomb structure of the present invention.

  Also, one embodiment of the bonded honeycomb structure of the present invention is provided with a plurality of the honeycomb structure of the present invention as a honeycomb segment, and the plurality of honeycomb segments are arranged side by side. Are arranged so as to face each other, and the opposite side surfaces are joined together by a joint portion. Thus, since the joining type honeycomb structure of this embodiment joins a some honeycomb segment, even if it enlarges, it becomes a thing with high thermal shock resistance. In the bonded honeycomb structure of the present embodiment, examples of the material of the bonded portion for bonding a plurality of honeycomb segments (the honeycomb structured body of the present invention) include cement. In addition, as a method for manufacturing a bonded honeycomb structure, a method in which a plurality of honeycomb structures (honeycomb segments) of the present invention are manufactured and then the honeycomb segments are bonded using a conventionally known method can be used.

[2] Manufacturing method of honeycomb structure:
Next, the manufacturing method of one embodiment of the honeycomb structure of the present invention will be specifically described.

  The method for manufacturing a honeycomb structured body of the present embodiment includes a step (1) of obtaining a columnar honeycomb formed body having partition walls that form a plurality of cells serving as fluid flow paths by forming a ceramic forming raw material. The opening of a predetermined cell (first cell) on one end surface (outflow side end surface) side of the formed honeycomb molded body is filled with plugging slurry, and the opening at the outflow side end of the predetermined cell Step (2) for obtaining a plugged honeycomb molded body plugged at the portion, and plugging the plugged portion of the obtained plugged honeycomb molded body from one end surface (end surface on the outflow side) side A step of drilling a through-hole penetrating to the inside of the predetermined cell that has stopped, and obtaining an open area reduced honeycomb formed body in which the area of the opening of the predetermined cell is reduced on one end surface (end surface on the outflow side) ( 3) and firing the obtained aperture area-reduced honeycomb formed body to obtain a honeycomb structure. A step of obtaining a body (4), a method for manufacturing a honeycomb structure with a.

  Hereinafter, the manufacturing method of the honeycomb structure of the present embodiment will be described in more detail for each step.

[2-1] Step (1):
The step (1) includes forming a ceramic forming raw material containing a ceramic raw material and partitioning a plurality of cells serving as fluid flow paths, and the cells are formed from the first cell and the second cell. becomes a first cell and the second cell are arranged alternately, in a cross section perpendicular to the flow path direction of the cell have size than the area of the area of the first cell is the second cell, the pillar-shaped honeycomb This is a step of obtaining a molded body. This step (1) can be performed according to a conventionally known method for manufacturing a honeycomb structure.

[2-2] Step (2):
In step (2), plugging slurry is filled in the opening of a predetermined cell (first cell) on one end face (end face on the outflow side) of the obtained honeycomb formed body, as shown in FIG. This is a step of obtaining a plugged honeycomb formed body in which a plugged portion is formed in the opening at the outflow side end of the first cell.

  In the method for manufacturing a honeycomb structure of the present embodiment, the end portion on the outflow side of the remaining cells (second cells) that do not form plugged portions is covered with a mask, and only the first cells are plugged slurry. Is preferably filled.

  The method for disposing the mask in the second cell is not particularly limited. For example, an adhesive film is attached to the entire one end face (outflow end face) of the honeycomb formed body, and the adhesive film is used. And a method of forming a hole at a position corresponding to the opening of the “first cell without mask”. More specifically, after sticking an adhesive film to one whole end face of the honeycomb formed body, a portion of the adhesive film corresponding to a cell (first cell) in which a plugging portion is to be formed. For example, a method of making a hole with a laser can be suitably used. As an adhesive film, what applied the adhesive to one surface of the film which consists of resin, such as polyester, polyethylene, a thermosetting resin, etc. can be used conveniently.

  Examples of the plugging slurry for forming the plugging portion include a slurry in which the above ceramic raw material and additive are blended. As an additive, water, a binder, a pore former, a surfactant and the like are mixed to adjust the viscosity to 150 to 400 dPa · s, and more preferably to 180 to 350 dPa · s.

  In addition, after forming the plugged portions with the plugging slurry in this way, the obtained plugged honeycomb formed body may be further dried.

[2-3] Step (3):
In the step (3), from one end face (outflow end face) side to the inside of the plugged predetermined cell (first cell) in the plugged portion of the obtained plugged honeycomb formed body A through-hole penetrating therethrough is drilled to obtain an open area-reduced honeycomb formed body in which the area of the opening of the first cell is reduced on one end face (end face on the outflow side). In this step (3), in the cross section orthogonal to the cell flow path direction, the area of the portion of the first cell where the opening area reducing member is not provided in the opening at the outflow side end is the second It is formed to 40% or more of the cell area.

  As described above, by forming the through hole in the plugged portion, it is possible to form the opening area reducing member disposed so as to block a part of the opening at the outflow side end of the first cell. .

  Although there is no restriction | limiting in particular about the method of drilling a through-hole, For example, as shown in FIG. 4, it can carry out using the jig 22 which has several needle-like protrusions 21 like a sword mountain. Such a jig 22 is preferably configured such that the plurality of needle-like protrusions 21 are located at the center of the opening at the outflow side end of the first cell 4a that pierces the through hole 33. . In addition, the hole diameter of the through hole 33 can be adjusted by the size of the outer diameter of the protrusion 21 of the jig 22. FIG. 4 is a cross-sectional view schematically showing a state in which through-holes are formed in the plugged portions of the plugged honeycomb formed body using the jig 22 to obtain an opening area reduced honeycomb formed body 200. . FIG. 4 shows a state where the jig 22 is removed from the opening area reduced honeycomb formed body 200, and shows a cross section orthogonal to the cell flow path direction of the opening area reduced honeycomb formed body. In the opening area-reduced honeycomb formed body 200, the plugging portions 32 in which the through holes 33 are formed are arranged at the end portion on the outflow side of the first cells 34 that are partitioned by the partition walls 31. As another method, a plugging slurry having a desired depth and a plugging slurry from the outflow side end face in a state where the outflow side end of the remaining cell (second cell) not forming the plugging part is covered with a mask. It is also possible to introduce the plugging slurry into the first cell and then pull it up and blow off the surplus slurry with compressed air as necessary. In this case, the opening area can be adjusted by the viscosity of the plugging slurry, the pressure of compressed air, and the like.

[2-4] Step (4):
Step (4) is a step of firing the obtained aperture area-reduced honeycomb formed body to obtain a honeycomb structure. In this way, the honeycomb structure of the present embodiment can be manufactured easily and at low cost. This step (4) can be performed according to a conventionally known method for manufacturing a honeycomb structure.

[3] Honeycomb catalyst body:
Next, an embodiment of the honeycomb catalyst body of the present invention will be specifically described. The honeycomb catalyst body of the present embodiment is supported on the inner surface of the pores of the partition walls of the honeycomb structure of the present invention described above (the honeycomb structure 100 shown in FIGS. 1 to 3) and the honeycomb structure. And a catalyst supported on the partition wall surface. In another embodiment of the honeycomb catalyst body of the present invention, the bonded honeycomb structure of the present invention and the inner surface of the pores of the partition walls of the honeycomb structure are supported on the partition wall surfaces. And a catalyst body. Hereinafter, the honeycomb catalyst body in which the catalyst is supported on the honeycomb structure will be described, but the same applies to the honeycomb catalyst body in which the catalyst is supported on the bonded honeycomb structure.

Such a honeycomb catalyst body allows exhaust gas discharged from automobile, construction machine, and industrial stationary engines, combustion equipment, and the like to flow into each cell from the end face on the inflow side, While purifying with the catalyst on the partition wall surface, it allows the partition wall to permeate and purifies harmful substances such as carbon monoxide (CO), hydrocarbon (HC), nitrogen oxide (NO _x ), etc. with the catalyst. The permeated fluid (purified gas) that has passed through the partition walls flows out from the opening on the end face on the outflow side of an adjacent cell.

  Since the honeycomb catalyst body of the present embodiment is one in which the catalyst is supported on the honeycomb structure of the present invention, the area of the cell opening on the outflow side end face of the first cell is reduced by the opening area reducing member. Therefore, a part of the fluid that has flowed into the first cell can permeate through the partition wall that defines the first cell, and can actively flow out into the adjacent second cell. The contained harmful substances can be efficiently purified.

  Further, in the honeycomb catalyst body of the present embodiment, the porosity and average pore diameter of the partition walls are in a specific range, and in the first cell, although the area of the opening is reduced, it is reduced. Since a part of the fluid can flow out from the opening (that is, the opening is not completely sealed), the exhaust gas purification efficiency is improved and the increase in pressure loss is effective as described above. Can be suppressed or pressure loss can be reduced.

  That is, the honeycomb catalyst body of the present embodiment can simultaneously solve the problems that are difficult to achieve with the conventional techniques, such as improving the purification efficiency of exhaust gas and suppressing the increase in pressure loss.

  Furthermore, in the honeycomb catalyst body of the present embodiment, since the area of the first cell is larger than the area of the second cell in the cross section orthogonal to the cell flow direction, the opening ratio of the plugged portion can be widely changed. It is possible to change the balance between purification performance and pressure loss according to the porosity and average pore diameter.

The catalyst used in the honeycomb catalyst body of the present embodiment is not particularly limited as long as it can purify harmful substances contained in the exhaust gas. For example, platinum (Pt), rhodium (Rh) as noble metals And those containing at least one selected from the group consisting of palladium (Pd) and further containing activated alumina and ceria as an oxygen storage agent. Such a catalyst is particularly effective for purification of harmful substances such as carbon monoxide (CO), hydrocarbons (HC), and nitrogen oxides (NO _x ).

  The amount of catalyst supported varies depending on the type of catalyst, the size and cell structure of the honeycomb structure used as the catalyst carrier, and the type and amount of exhaust gas to be purified. For example, per 1 L of the honeycomb structure volume Further, it is preferable that 100 to 250 g of catalyst is supported. By comprising in this way, the purification | cleaning efficiency of exhaust gas can be improved and the increase in pressure loss can be suppressed effectively. The amount of the catalyst supported is more preferably 100 to 250 g, particularly preferably 150 to 230 g per 1 L of the honeycomb structure volume.

  The amount of the catalyst supported on the inner surface of the pores of the partition walls is preferably equal to or greater than the amount of the catalyst supported on the partition surface. If the catalyst supported on the inner surface of the pores of the partition walls is not equal to or greater than the amount of the catalyst supported on the partition surface, the surface area in the pores cannot be used effectively and the purification rate may deteriorate.

[3-1] Manufacturing method of honeycomb catalyst body:
Next, an example of a method for manufacturing the honeycomb catalyst body of the present embodiment will be described. Note that the method for manufacturing the honeycomb catalyst body of the present embodiment is not limited to the following method. Also, a method for supporting a catalyst on a honeycomb structure to form a honeycomb catalyst body will be described, but the same applies to a case where a catalyst is supported on a bonded honeycomb structure to form a honeycomb catalyst body.

  First, a honeycomb structure constituting the catalyst carrier of the honeycomb catalyst body of the present embodiment is manufactured. In the honeycomb catalyst body of the present embodiment, since the honeycomb structure of the present invention described so far is used, the honeycomb structure according to one embodiment of the manufacturing method of the honeycomb structure of the present embodiment described above. Can be manufactured.

  Next, the catalyst is supported on the partition wall surfaces of the obtained honeycomb structure and the inner surfaces of the pores of the partition walls. The catalyst loading method is not particularly limited, and the catalyst can be loaded according to a method used in a conventionally known honeycomb catalyst body manufacturing method. For example, the honeycomb structure is washed with a catalyst solution containing a catalyst component, and then the excess slurry is blown off with compressed air or the like and baked by heat treatment at a high temperature, so that the catalyst solution does not block the partition pores. For example, the method etc. which carry out a deaeration process and carry | support a catalyst can be mentioned.

  EXAMPLES Hereinafter, although this invention is demonstrated concretely based on an Example, this invention is not limited to these Examples. Each physical property was measured by the following method.

[Average pore diameter (μm)]: The pore diameter was measured by a mercury porosimeter (mercury intrusion method), and the cumulative volume of mercury injected into the porous substrate was the total pore volume of the porous substrate. It means the pore diameter calculated from the pressure when it becomes 50%. As the mercury porosimeter, the product name: Auto Pore III Model 9405 manufactured by Micromeritics was used.

[Porosity (%)]: Similar to the pore diameter, a mercury porosimeter was used.

[Catalyst loading (g / L)]: The catalyst loading (W / C) amount (g / L) per liter of the volume of the honeycomb structure as the catalyst carrier was calculated.

[Platinum group metal loading (g / L)]: The platinum group metal loading (g / L) contained in the catalyst per 1 L volume of the honeycomb structure as the catalyst carrier was calculated. The platinum group metal is configured such that the ratio of platinum (Pt) to rhodium (Rh) (Pt: Rh) is 5: 1.

[Opening ratio of through hole]
In the cross section orthogonal to the cell flow path direction, the opening area of the first cell (cell having a large cross-sectional area) and the opening area of the opening area reducing member disposed in the first cell (formed on the opening area reducing member) And the opening area of the second cell (cell having a small cross-sectional area) is measured by image analysis. As an application range of the image analysis, an end surface center portion of 5 × 5 cells or more is set as an analysis range, and a portion where the opening area of the opening area reducing member is narrowest is measured. Then, the ratio of the “opening area of the opening area reducing member” to the “opening area of the first cell” (opening ratio of the through hole) is calculated.

[Pressure loss (kPa)]: A measurement gas (air) at 25 ° C. and 1 atm was passed through the honeycomb catalyst body to measure the pressures at the end face on the inflow side and the end face on the outflow side. The pressure difference was defined as pressure loss (kPa). Measurements of the pressure, the flow rate of the measurement gas, up to 0.92 nm ³ / min 9.91Nm ³ / min, to increase the flow rate by about 1 Nm ³ / min, was measured a total of 10 times.

[Hazardous component emission (g / mile)]: The measurement of the harmful component emission was performed by disposing the honeycomb catalyst body of each example or comparative example in the exhaust system of a gasoline engine vehicle having a displacement of 2 liters. The engine vehicle was operated in the FTP (US federal regulation, LA-4) operation mode, and the emission amount (g) of harmful components contained in the exhaust gas discharged per mile of the mileage was measured. As harmful components, the amount (g) of hydrocarbon (HC) in the exhaust gas (HC emission amount) and the amount of nitrogen oxide (NO _X ) (g) (NO _X emission amount) were measured. The amount of harmful component discharge was measured when the platinum group metal loading was 1 g / L and when the platinum group metal loading was 2 g / L. In addition, the platinum group metal supported amount of the honeycomb catalyst body of the example is 2 g / L, and the platinum group metal supported amount of the honeycomb catalyst body of the comparative example is 2.5 g / L. In addition, in the honeycomb catalyst bodies of the examples and comparative examples, the platinum group metal loadings were 1 g / L (for the comparative examples, 1 g / L and 2 g / L) were measured and measured.

Example 1
Talc, combined kaolin, calcined kaolin, alumina, aluminum hydroxide, and a plurality from among silica, the chemical _composition, SiO 2 42 to 56 _{wt%, Al} 2 O 3 0 to 45 wt%, and MgO12~ 10-20 parts by mass of graphite was added as a pore former to 100 parts by mass of the cordierite forming raw material prepared at a predetermined ratio so as to be 16% by mass. Furthermore, after adding appropriate amounts of methyl cellulose and surfactant, the prepared clay was vacuum degassed, and then extrusion molded to obtain a honeycomb formed body. The honeycomb molded body has a partition wall thickness of 200 μm (8 mil) and a cell density of 62 cells / cm ² (400 cpsi). Note that “1 (mil)” is 1/1000 inch, and “cpsi” is “cell / square inch”. As shown in FIG. 5, the obtained honeycomb formed body 300 includes partition walls 41 that partition and form a plurality of cells 42, and the end face of the honeycomb structure (even in a cross section orthogonal to the flow direction of the cells 42). Similarly, the first cells 42a having a large area in the cells 42 and the second cells 42b having a small area are alternately arranged. FIG. 5 is a front view schematically showing the honeycomb formed body produced in Example 1 as seen from one end face side.

Next, a plugged portion is formed in the opening of the end portion on the outflow side of the first cell 42a having a large area in the cross section perpendicular to the cell flow path direction of the obtained honeycomb molded body, A sealed honeycomb formed body was obtained . The plugging slurry to form the plugged portions was used slurry containing a combination of additives with the cordierite forming material. The length (arrangement depth) of the plugged portion in the cell flow path direction was set to 0.3 to 10 mm.

Next, a through-hole penetrating from the end surface on the outflow side to the inside of the plugged cell is drilled in the plugged portion of the obtained plugged honeycomb formed body, and a predetermined cell (first cell) is formed. ) In which the area of the opening was reduced at the end face on the outflow side. Here, the plugged portion in which the through hole is formed is an opening area reducing member. In addition, “the area of the opening portion of the first cell where the opening area reducing member is not disposed (the opening portion of the opening area reducing member)” and “the area of the second cell” The area ratio was 3: 2. In this example, the through hole was drilled so that the opening ratio (%) of the through hole of the opening area reducing member of the first cell was 5%.

Next, the obtained opening area-reduced honeycomb formed body was fired to manufacture a honeycomb structure. Table 1 shows the partition wall thickness (μm), cell density (cell / cm ² ), average pore diameter (μm), and porosity (%) of the honeycomb structure.

Next, a catalyst containing a platinum group metal prepared so that the ratio (Pt: Rh) of platinum (Pt) and rhodium (Rh) is 5: 1 is added to the obtained honeycomb structure. A honeycomb catalyst body was manufactured by supporting the catalyst so that the amount was 160 g / L (Example 1). As the promoter of the supported catalyst, cerium (Ce) oxide (CeO ₂ ) and zirconium (Zr) oxide (ZrO ₂ ) were used. The platinum group metal loading is 2 g / L.

  With respect to the honeycomb catalyst body of Example 1, the above-described opening ratio of the through holes was measured, and the pressure loss and the harmful component discharge amount were measured. Table 1 shows the measurement results of the opening ratio of the through holes, Table 2 shows the measurement results of the pressure loss, and Table 3 shows the measurement results of the harmful component discharge amount.

(Examples 2 and 3)
Except for changing the opening ratio of the through holes as shown in Table 1, a honeycomb structure having the same configuration as in Example 1 was manufactured, and the obtained honeycomb structure was subjected to the same method as in Example 1. A catalyst was supported to produce a honeycomb catalyst body (Examples 2 and 3). For each of the honeycomb catalyst bodies of Examples 2 and 3, the opening ratio of the notch, the pressure loss, and the harmful component discharge amount were measured. The results are shown in Tables 1-3.

(Comparative Examples 1-3)
The partition wall thickness (μm), cell density (cell / cm ² ), average pore diameter (μm), porosity (%), and through-hole opening ratio (%) were set to the values shown in Table 1, respectively. Produced a honeycomb structure in the same manner as in Example 1, and as shown in Table 1, a catalyst was supported on the obtained honeycomb structure so that the amount of the catalyst supported was 200 g / L. (Comparative Examples 1-3). The platinum group metal loading was 2.5 g / L. About the honeycomb catalyst body of Comparative Examples 1-3, the measurement of the said pressure loss and the measurement of harmful component discharge | emission amount were performed. The results are shown in Tables 2 and 3.

(Result 1)
As shown in Table 2 and FIG. 7, in the measurement of pressure loss, the honeycomb catalyst body of Comparative Example 2 showed the highest pressure loss. The honeycomb catalyst body of Example 1 showed a higher value than Comparative Example 1 at a flow rate of the measurement gas of 6 Nm ³ / min or more, but Examples 2 and 3 were higher than Comparative Example 1 up to 10 Nm ³ / min. It showed a low value. When compared at 8 Nm ³ / min, the honeycomb catalyst body of Example 3 has a pressure loss reduced by about 20% compared to the honeycomb catalyst body of Comparative Example 1. FIG. 7 is a graph showing the measurement result of the pressure loss, the horizontal axis indicates the flow rate (Nm ³ / min) of the measurement gas, and the vertical axis indicates the pressure loss (kPa).

Moreover, as shown in Table 3, FIG. 8, and FIG. 9, in the measurement of harmful component discharge, it can be seen that the purification performance improves as the aperture ratio of the through holes decreases. In particular, in Comparative Example 2, since the flow rate of the gas in the second cell is increased due to the small opening ratio of the through hole, the gas was pulled from the first cell side toward the second cell side. It is considered a thing. Further, it is recognized that when the amount of harmful components discharged is the same as that of the honeycomb catalyst body of Comparative Example 1, the platinum group metal loading of the honeycomb catalyst body of Comparative Example 2 may be reduced by about 60%. Moreover, in the case of the platinum group metal loading of the honeycomb catalyst body of Example 1, it is recognized that there is a possibility that it can be reduced by about 40%. FIG. 8 and FIG. 9 are graphs showing the measurement results of the harmful component emission amount, wherein the horizontal axis indicates the platinum group metal loading (g / L) and the vertical axis indicates the harmful component emission amount (g / mile). . 8 shows the result of measuring hydrocarbon (HC) as a harmful component, and FIG. 9 shows the result of measuring nitrogen oxide (NO _x ) as a harmful component.

  FIG. 10 shows the relationship between pressure loss and harmful component discharge. FIG. 10 shows the ratio of each of Examples 1 to 3 and Comparative Examples 2 and 3 to the pressure loss and harmful component discharge amount of Comparative Example 1, and the horizontal axis represents the pressure loss of Comparative Example 1. Is a ratio when the toxic component emission amount of Comparative Example 1 is 1. As shown in FIG. 10, the honeycomb catalyst bodies of Examples 1 to 3 and Comparative Examples 2 and 3 are trade-off lines X in which a reduction of 10% is confirmed with respect to the pressure loss and harmful component discharge amount of Comparative Example 1. It was possible to achieve a trade-off between pressure loss and purification performance. In addition, the above-mentioned “tradeoff line in which a reduction of 10% is confirmed” means that the square root of the value obtained by integrating the ratio of the pressure loss and the ratio of the harmful component emission amount is 0.9 (that is, Comparative Example 1). It is a curve connecting points that are 90%).

(Examples 4 to 7)
A honeycomb structure manufactured in the same manner as in Example 2 (through-hole opening ratio 50%) except that the average pore diameter (μm) and porosity (%) were changed as shown in Table 4 was manufactured. Then, the obtained honeycomb structure was loaded with a catalyst by the same method as in Example 1 to manufacture honeycomb catalyst bodies (Examples 4 to 7). For each of the honeycomb catalyst bodies of Examples 4 to 7, the above-described pressure loss measurement and harmful component discharge amount measurement were performed. The results are shown in Tables 5 and 6. Here, FIG. 11 is a graph showing the measurement result of the pressure loss, the horizontal axis indicates the flow rate of the measurement gas (Nm ³ / min), and the vertical axis indicates the pressure loss (kPa). FIGS. 12 and 13 are graphs showing the measurement results of the harmful component emission amount. The horizontal axis represents the platinum group metal loading (g / L), and the vertical axis represents the harmful component emission amount (g / mile). Indicates. FIG. 12 shows the result of measuring hydrocarbon (HC) as a harmful component, and FIG. 13 shows the result of measuring nitrogen oxide (NO _X ) as a harmful component.

(Result 2)
As shown in Table 5 and FIG. 11, in the measurement of the pressure loss, the honeycomb catalyst bodies of all the examples exhibited values (pressure loss) lower than the honeycomb catalyst body of Comparative Example 1 up to 10 Nm ³ / min. . When compared with the gas flow rate of 8 Nm ³ / min, it can be seen that the pressure loss of the honeycomb catalyst body of Example 7 is reduced by about 40% compared to the honeycomb catalyst body of Comparative Example 1.

  Further, as shown in Table 6, FIG. 12 and FIG. 13, it can be seen that the purification performance improves as the porosity increases in the measurement of harmful component discharge (Examples 2, 6 and 7). It can also be seen that the purification performance improves as the average pore diameter increases (Examples 2, 4 and 5). Further, it is recognized that when the amount of harmful components discharged is the same as that of the honeycomb catalyst body of Comparative Example 1, the platinum group metal loading of the honeycomb catalyst body of Example 5 may be reduced by about 60%. Moreover, in the case of the platinum group metal loading of the honeycomb catalyst body of Example 4, it is recognized that there is a possibility that it can be reduced by about 20%.

  FIG. 14 shows the relationship between pressure loss and harmful component discharge. In FIG. 14, the ratio of each Example 2, 4-7 with respect to the pressure loss and harmful component discharge | emission amount of the comparative example 1 is shown, and the horizontal axis made the pressure loss of the comparative example 1 1 And the vertical axis represents the ratio when the harmful component emission amount of Comparative Example 1 is 1. As shown in FIG. 14, the honeycomb catalyst bodies of Examples 2 and 4 to 7 exceeded the trade-off line in which a reduction of 10% was confirmed with respect to the pressure loss and harmful component discharge amount of Comparative Example 1, and the pressure loss It was possible to achieve both the trade-off between cleansing performance and purification performance.

The honeycomb structure according to the present invention supports carbon monoxide (CO) and hydrocarbons contained in exhaust gas discharged from automobiles, construction machines, industrial stationary engines, combustion equipment, and the like by supporting a catalyst. (HC) and nitrogen oxides (NO _x ) can be efficiently purified, and an increase in pressure loss can be effectively suppressed, which can be suitably used as a catalyst carrier of a honeycomb catalyst body. it can.

Moreover, the honeycomb catalyst body of the present example is a carbon monoxide (CO), hydrocarbon (HC) contained in exhaust gas discharged from automobiles, construction machinery, industrial stationary engines, combustion equipment, and the like. It can be suitably used to purify harmful components such as nitrogen oxides (NO _x ).

1 is a perspective view schematically showing an embodiment of a honeycomb structure of the present invention. Fig. 3 is a plan view schematically showing one embodiment of a honeycomb structure of the present invention as seen from the outflow side end face side. It is a schematic diagram which shows the A-A 'cross section of FIG. [Fig. 3] Fig. 3 is a cross-sectional view schematically showing a state in which a through-hole is formed in a plugged portion of the plugged honeycomb formed body using a jig to obtain an aperture area reduced honeycomb formed body. 1 is a front view schematically showing a honeycomb formed body produced in Example 1 as viewed from one end face side. FIG. [Fig. 3] Fig. 3 is a schematic view showing the arrangement of cells in a cross section perpendicular to the flow path direction of cells in one embodiment of the honeycomb structure of the present invention. It is a graph which shows the measurement result of the pressure loss in an Example. It is a graph which shows the measurement result of the harmful | toxic component (HC) discharge | emission amount in an Example. It is a graph showing the measurement results of the harmful components (NO _X) emissions in Example. It is a graph which shows the relationship between the pressure loss and harmful component discharge | emission amount in an Example. It is a graph which shows the measurement result of the pressure loss in an Example. It is a graph which shows the measurement result of the harmful | toxic component (HC) discharge | emission amount in an Example. It is a graph showing the measurement results of the harmful components (NO _X) emissions in Example. It is a graph which shows the relationship between the pressure loss and harmful component discharge | emission amount in an Example.

Explanation of symbols

1: partition wall, 2: inflow side end surface, 3: outflow side end surface, 4: cell, 4a, 52: first cell, 4b, 53: second cell, 5: honeycomb structure, 6: opening area Reduction member, 7: through hole, 11: outer peripheral wall, 21: protrusion, 22: jig, 31: partition wall, 32: plugged portion in which the through hole is formed, 33: through hole, 34: first cell 41: partition, 42: cell, 42a: first cell, 42b: second cell, 51a, 51b: center line, 54: other first cell, 55: other second cell, 100: Honeycomb structure, 200: opening area reduced honeycomb formed body, 300: honeycomb formed body, D: deviation width, E: distance between center points.

Claims (5)

A columnar honeycomb structure part having a porous partition wall and penetrating from the end surface on the inflow side to the end surface on the outflow side by the partition wall, in which a plurality of cells serving as fluid flow paths are partitioned;
The partition wall has a porosity of 50 to 80% and an average pore diameter of 13 to 70 μm,
In some of the plurality of cells, an opening area reducing member is formed so that an opening at an end portion on an inflow side is opened and a part of the opening portion is blocked by an opening at an end portion on an outflow side. The first cell disposed, the remaining cell is a second cell having openings at both ends,
The first cells and the second cells are alternately arranged,
In the cross section perpendicular to the flow direction of the cell, the area of the first cell is larger than the area of the second cell,
In the cross section perpendicular to the cell flow path direction, the area of the first cell in the opening portion at the outflow side end portion where the opening area reducing member is not disposed is the area of the second cell. Ri der more than 40%,
In the cross section perpendicular to the cell flow direction, the opening of the opening area reducing member is the area of the first cell where the opening area reducing member is not provided in the opening at the outflow side end. area, 5% to 80% der Ru honeycomb structure opening area of the first cell. The honeycomb structure according to claim 1, wherein the opening area reducing member is made of a porous body having a porosity of 20 to 80%. A plurality of honeycomb structures according to claim 1 or 2 as honeycomb segments,
A joined honeycomb structure in which the plurality of honeycomb segments are arranged adjacent to each other so that the side surfaces thereof are opposed to each other, and the opposed side surfaces are joined to each other by a joining portion. A honeycomb structure according to claim 1 or 2, and a catalyst supported on the inner surface of the pores of the partition walls of the honeycomb structure and a catalyst supported on the partition wall surfaces,
A honeycomb catalyst body having a catalyst loading of 100 to 250 g / L. A bonded honeycomb structure according to claim 3 , and a catalyst supported on the inner surface of the pores of the partition walls of the bonded honeycomb structure, and a catalyst supported on the partition wall surfaces,
A honeycomb catalyst body having a catalyst loading of 100 to 250 g / L.

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