JP5219740B2 - Honeycomb structure and honeycomb catalyst body - Google Patents

Description

The present invention relates to a honeycomb structure and a honeycomb 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 such as nitrogen oxide (NO _x ) and effectively suppressing an increase in pressure loss, and a catalyst supported on the honeycomb structure Relates to the 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.

  At present, the honeycomb structure used in such a honeycomb catalyst body increases the cell density, increases the geometric area on which the catalyst is supported, and increases the exhaust gas and the catalyst in order to improve the exhaust gas purification performance. It is 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.

  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.

  As a result of intensive investigations to solve the problems of the prior art as described above, the inventor of the present invention, in a honeycomb structure including a honeycomb structure portion having porous partition walls having a specific porosity and average pore diameter, All the openings of the cells on the end face on the inflow side are opened, and only a specific cell on the end face on the outflow side is provided with a plugging portion that seals the opening, and of the specific cells A communication hole is formed on at least one surface of the partition wall that partitions at least one or more cells, in the vicinity of the end on the outflow side where the plugging portion is disposed. As a result, the inventors have conceived that the above-mentioned problems can be solved and completed the present invention. Specifically, according to the present invention, the following honeycomb structure and honeycomb catalyst body are provided.

[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 wall has a porosity of 50 to 80% and an average pore diameter of 13 to 70 μm, and the plurality of cells are perpendicular to the flow path direction of the cells from the end surface on the inflow side to the end surface on the outflow side. An outflow side provided with a cell having an open end on both ends formed with a constant cross-sectional area and a plugging portion for sealing an end of a predetermined length from the end surface on the outflow side of the cell And at least one outflow side opening sealed cell is disposed with the both-end opening open cell and the partition separated from each other, and the partition includes at least one of the above-described partition walls. Fewer partition walls for partitioning outflow side opening sealing cells In one surface, in the vicinity of the end portion on the outflow side where the plugging portion is disposed, a communication hole that connects the outflow side opening sealing cell and the both end opening open cells is formed, In the communication hole, the ratio of the total area of the openings of all the communication holes to the total area of the region where the plugging portions are disposed on the end surface on the outflow side is 25 to 100%. The communication hole is formed in the one outflow side opening end with respect to the area of the region where the plugging portion is disposed on the outflow side end face of one outflow side opening end portion sealing cell. A honeycomb structure formed such that the ratio of the total area of the opening portions of the communication holes formed in the partition walls forming the partial sealing cells is 25 to 100% .

[2] The honeycomb structure according to [1], wherein the both-end opening open cells and the outflow side opening sealed cells are alternately arranged with the partition walls therebetween.

[ 3 ] The honeycomb structure according to [1] or [2] , wherein the communication hole has a circular opening.

[ 4 ] The communication hole is formed on at least one surface of the partition wall that defines 90% or more of the outflow side opening sealed cells among all the outflow side opening sealed cells. ] The honeycomb structure according to any one of [ 3 ].

[ 5 ] The honeycomb structure according to any one of [1] to [ 4 ], 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; And a honeycomb catalyst body.

[ 6 ] The honeycomb catalyst body according to [ 5 ], wherein the catalyst is supported in an amount of 100 to 250 g per 1 L of the volume of the honeycomb structure.

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. It is possible to efficiently purify harmful substances such as (HC) and nitrogen oxides (NO _x ), and to effectively suppress an increase in pressure loss. Further, the honeycomb catalyst body of the present invention is a catalyst in which the above-described honeycomb structure of the present invention is supported, and it is possible to efficiently purify harmful substances contained in exhaust gas and to reduce pressure loss. The increase can be effectively suppressed.

  Specifically, the outflow side opening sealing cell constituting the honeycomb structure part of the honeycomb structure of the present invention has a cell opening on the end surface on the outflow side being sealed, so When used as a catalyst body, the fluid (exhaust gas) that has flowed into the outflow side opening sealed cell permeates through the partition wall forming the cell and actively flows out into the adjacent open end cell. The harmful substances contained in the exhaust gas can be efficiently purified by the catalyst supported on the inner surface of the pores of the partition walls and the surface of the partition walls.

  Further, 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 end portion on the outflow side is sealed in the outflow side opening sealed cell. However, since the communication hole communicates with the open-ended cell at both ends (that is, the cell is not completely closed), even if the exhaust gas purification efficiency is improved as described above, the pressure loss Can be effectively suppressed, or 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 improvement of exhaust gas purification efficiency and suppression of increase in pressure loss.

  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:
First, an embodiment of the honeycomb structure of the present invention will be specifically described. Here, FIG. 1A is a perspective view schematically showing an embodiment of the honeycomb structure of the present invention, and FIG. 1B is an enlarged plan view in which an end face on the outflow side of the honeycomb structure shown in FIG. 1A is enlarged. 1C is a schematic cross-sectional view schematically showing the AA ′ cross section of FIG. 1B, and FIG. 1D is a schematic cross-sectional view schematically showing the BB ′ cross section of FIG. 1B.

  As shown in FIG. 1A to FIG. 1D, the honeycomb structure 1 of the present embodiment has a porous partition wall 12, and the partition wall 12 penetrates from the end surface 32 on the inflow side to the end surface 34 on the outflow side. The honeycomb structure 1 includes a columnar honeycomb structure 2 in which a plurality of cells 14 serving as flow paths are partitioned. Note that the honeycomb structure 1 of the present embodiment has an outer peripheral wall 16 disposed so as to surround the outer periphery of the partition wall 12 that defines the cells 14.

The honeycomb structure 1 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 manufactured by supporting a catalyst on the inner surface of the pores of the partition wall and the partition surface, and the honeycomb catalyst body is disposed inside the exhaust system of the exhaust gas and flows into the honeycomb catalyst body. The fluid (exhaust gas) flows into each cell from the end face on the side, and the inflowed exhaust gas permeates through the partition walls that define the cell, thereby oxidizing carbon monoxide (CO), hydrocarbon (HC), and nitrogen. It can be suitably used as a honeycomb catalyst body for purifying harmful substances such as substances (NO _x ).

  In the honeycomb structure 1 of the present embodiment, the porous partition walls 12 constituting the honeycomb structure portion 2 have a porosity of 50 to 80% and an average pore diameter of 13 to 70 μm. Thus, in the honeycomb structure 1 of the present embodiment, the partition walls 12 are formed by a porous body having a higher porosity and a larger average pore diameter than the honeycomb structure used in the conventional honeycomb catalyst body. The honeycomb structure portion 2 is provided. 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. Depending on the use conditions, it is possible to reduce the pressure loss without degrading the purification performance as compared with the conventional honeycomb catalyst body.

  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, as shown in FIGS. 1A to 1D, the honeycomb structure 1 of the present embodiment includes a plurality of cells 14 partitioned and formed by partition walls 12 from the end surface 32 on the inflow side to the end surface 34 on the outflow side. Both-end opening open cells 14a formed with a constant cross-sectional area perpendicular to the flow path direction, and plugging portions for sealing an end 44 having a predetermined length from the end surface 34 on the outflow side of the cell 14 The at least one outflow side opening sealing cell 14b is arranged with the both-end opening opening cell 14a and the partition wall 12 separated from each other. .

  As described above, in the honeycomb structure 1 of the present embodiment, all the openings in the inflow side end faces 32 of all the cells 14 are opened, and in the outflow side end face 34, the outflow side opening sealed cells 14b. The opening is sealed by the plugging portion 18. In addition, it is preferable that the both-end opening part open cell 14a and the outflow side opening part sealing cell 14b are alternately arrange | positioned across the partition 12, and in that case, about half of all the cells 14 are cells. Both-end opening portion open cells 14a become, and the remaining approximately half of the cells become outflow side opening sealed cells 14b. Note that, as described above, in the honeycomb structure of the present embodiment, the open-end opening cells and the outflow-side opening-sealed cells are alternately separated by the partition walls, that is, the cell openings on the outflow side are provided. A configuration in which the cells are plugged in a zigzag shape is preferable. The present invention is also included in the present invention.

  The partition wall 12 constituting the honeycomb structure portion 2 is an end portion on the outflow side where the plugging portion 18 is disposed on at least one surface of the partition wall 12 defining and forming at least one outflow side opening sealing cell 14b. 44, a communication hole 22 is formed in the vicinity of the outflow side opening sealing cell 14b and the both end opening open cells 14a. The communication hole 22 is connected to the plugging portion 18 at the end surface 34 on the outflow side. All the communication holes formed in the partition wall 12 with respect to the total area of the disposed regions (that is, the area (total area) of all the regions where the plugging portions 18 are disposed on the end surface 34 on the outflow side). The ratio of the total area of the 22 openings (that is, the total area of the openings of the communication holes 22) is 25 to 100%.

  The “area where the plugging portion is disposed” means the area of the cross section in the depth direction of the plugging portion, that is, the area of the sealed opening portion in the outflow side opening sealing cell. The “total area of the region in which the plugged portions are disposed” refers to the total area of the sealed openings in the outflow side opening sealed cells.

  The honeycomb structure 1 of the present embodiment is adjacent to the fluid (exhaust gas) that has flowed into the outflow side opening sealing cell 14b through the partition walls 12 that form the outflow side opening sealing cell 14b. It is comprised so that it can be made to flow out actively to the both-ends opening part open cell 14a. For this reason, the purification | cleaning efficiency of exhaust gas can be improved effectively by increasing the quantity (flow volume) of the fluid which permeate | transmits the partition 12. FIG.

  In the honeycomb structure 1 of the present embodiment, the opening portion of the outflow side end face 34 of the outflow side opening portion sealing cell 14b is sealed by the plugging portion 18, but the plugging of the partition walls 12 is performed. Since the communication hole 22 is formed in the vicinity of the end portion 44 on the outflow side where the portion 18 is disposed, the fluid (exhaust gas) that has not permeated through the partition wall 12 is opened at both ends adjacent to the partition wall 12. The open cell 14 a can be moved through the communication hole 22. Thus, in the honeycomb structure 1 of the present embodiment, the outflow side of the outflow side opening sealing cell 14b is not completely closed, and even if the exhaust gas purification efficiency is improved as described above. Thus, an increase in pressure loss can be effectively suppressed.

  Further, the open cell 14a at both ends opens through the inside of the cell 14 by the fluid that flows in through the partition wall 12 from the adjacent outflow side opening sealed cell 14b and the fluid that flows in through the communication hole 22. Since the fluid to be stirred is agitated, the contact efficiency with the catalyst supported on the surface of the partition wall 12 is improved, and the purification performance can be improved more effectively.

[1-1] Honeycomb structure part:
The honeycomb structure of the present embodiment has a porous partition, and a columnar honeycomb in which a plurality of cells serving as fluid flow paths penetrating from the end surface on the inflow side to the end surface on the outflow side are partitioned by the partition wall. It has a structural part. Note that the honeycomb structure portion constituting the honeycomb structure of the present embodiment further includes an outer peripheral wall disposed so as to surround the outer periphery of the partition wall that defines and forms the cells.

  As described above, this partition wall has a porosity of 50 to 80% and an average pore diameter of 13 to 70 μm, and the lower limit of the partition wall porosity is preferably 60% or more, and more than 65%. In addition, the upper limit is preferably 80% or less, and more preferably 75% 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.

  In addition, when the porosity of the partition is less than 50%, the opening of a specific cell (that is, the outflow side opening sealing cell) is sealed by the plugging portion, and further, the plugging portion of the partition is Even if the communication hole is formed near the end on the outflow side, the porosity of the partition wall is too low, the pore surface area of the partition wall is reduced, the effect of improving the purification efficiency, and the pressure loss It becomes impossible to achieve the effect of suppressing the increase. 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.

  Moreover, it is preferable that the average pore diameter of the partition walls of the honeycomb structure part constituting the honeycomb structure is 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 16 to 93 cells ^/ cm 2 ^{(100~600cpsi),} more preferably from 42-62 cells ^/ cm 2 ^{(300~400cpsi).} When the cell density is less than 16 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 80-450 micrometers, and it is still more preferable that it is 230-330 micrometers. If the partition wall thickness is less than 80 μm, the strength may be insufficient and thermal shock resistance may decrease, and if it exceeds 450 μm, 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 disposed so as to surround the partition wall is not particularly limited, for example, a circle, an ellipse, an ellipse, a trapezoid, A triangular shape, a rectangular shape, a hexagonal shape, or a left-right asymmetrical irregular shape can be mentioned. Of these, a circle, an ellipse, and an ellipse 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.

  The honeycomb structure of the present embodiment has, for example, a plurality of fluid passages that have a porous partition wall and pass through from the end surface on the inflow side to the end surface on the outflow side. It may be a honeycomb structure having a structure in which a plurality of columnar honeycomb segments in which cells are partitioned are combined via a bonding material layer (hereinafter also referred to as “bonded honeycomb structure”).

  Even in such a bonded honeycomb structure in which a plurality of honeycomb segments are integrated by a bonding material layer, the porous partition walls constituting each honeycomb segment have a porosity of 50 to 80%. In addition, both end openings having an average pore diameter of 13 to 70 μm and a plurality of cells each having an area of a cross section perpendicular to the flow direction of the cells from the end face on the inflow side to the end face on the outflow side are formed in a constant size An open cell, and an outflow side opening sealing cell provided with a plugging portion for sealing an end portion of a predetermined length from the end surface on the outflow side of the cell, and at least one outflow side opening The partial sealing cell is arranged with the both-end opening open cell and the partition wall, and the partition wall includes a plugging portion on at least one surface of the partition wall that defines at least one outflow side opening sealing cell. Near the end on the outflow side. A communication hole that connects the side opening sealing cell and the both-end opening open cell is formed, and this communication hole is all for the total area of the region where the plugging portion is disposed on the end surface on the outflow side. By forming the ratio of the total area of the openings of the communication holes to be 25 to 100%, it is possible to effectively improve the exhaust gas purification efficiency.

[1-2] Cell:
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, it is configured so that harmful substances can be purified by the inner surface of the pores of the partition walls and the catalyst supported on the partition surface, and the obtained purified gas can be discharged as purified gas from the end face on the outflow side. .

  As shown in FIGS. 1A to 1D, in the honeycomb structure 1 of the present embodiment, a plurality of cells 14 have a cross section perpendicular to the flow direction of the cells 14 from the end surface 32 on the inflow side to the end surface 34 on the outflow side. The outflow side in which the open end cell 14a having both ends formed in a constant size and the plugging portion 18 for sealing the end 44 having a predetermined length from the end surface 34 on the outflow side of the cell 14 are disposed. And an opening sealing cell 14b. In the honeycomb structure 1 of the present embodiment, at least one outflow side opening sealed cell 14b is disposed with the both end opening open cells 14a and the partition walls 12 therebetween. In the honeycomb structure 1 shown in FIGS. 1A to 1D, the opening portions of the cells 14 are plugged in a staggered manner by the plugging portions 18 on the end surface 34 on the outflow side, and the both end opening portion open cells 14 a and outflows. The side opening sealing cells 14b are alternately arranged with the partition walls 12 therebetween.

  As described above, in the honeycomb structure 1 of the present embodiment, the openings on the inflow side end surfaces 32 of all the cells are opened, while the outflow side end surface 34 has a specific cell (outflow side opening). The opening of the sealing cell 14 b) is sealed by the plugging portion 18.

  When exhaust gas flows in from the opening on the inflow side end face 32 of the outflow side opening sealing cell 14b, the flow rate of the exhaust gas decreases as it moves to the outflow side end face 34, and the outflow side opening sealing cell. The pressure at 14b also increases. On the other hand, the open end cell 14a at both ends has a constant cross-sectional area perpendicular to the flow direction of the cell from the end surface 32 on the inflow side to the end surface 34 on the outflow side. Compared with the sealing cell 14b, an increase in pressure on the end surface 34 side on the outflow side is reduced. For this reason, the exhaust gas that has flowed into the outflow side opening sealing cell 14b moves through the partition wall 12 into the both-end opening open cell 14a where the pressure in the cell is relatively low. In addition, purification with a catalyst is effectively performed.

[1-2a] Both-end opening open cell:
Both-end opening open cell 14a is a cell 14 in which the area of a cross section perpendicular to the cell flow path direction is formed in a constant size from the end surface 32 on the inflow side to the end surface 34 on the outflow side. In other words, the flow path penetrates from the end surface 32 on the inflow side to the end surface 34 on the outflow side, only formed by the partition walls 12 constituting the honeycomb structure portion 2.

  The open-ended cells at both ends need only have a constant cross-sectional area perpendicular to the flow direction of the cell from the end surface on the inflow side to the end surface on the outflow side in each open-end cell at both ends. The areas of the cross sections perpendicular to the flow path direction between the open cells at both ends need not be the same. That is, for example, the open-ended cell at both ends may be configured by two or more types of cells having different cross-sectional shapes perpendicular to the cell flow path direction and different cross-sectional area sizes. Of course, in all open-ended cells at both ends, the shape of the cross section perpendicular to the flow path direction may be the same.

  The shape of the cross section perpendicular to the flow path direction of the open-ended cell at both ends is not particularly limited. For example, a triangle, a quadrangle, a hexagon, an octagon, a circle, or a combination thereof (for example, an octagonal cell and a quadrangle) In combination with the cell). The honeycomb structure of the present embodiment preferably has a polygonal shape such as a quadrangle or a hexagon. In addition, when the cross-sectional shape of the cell is circular, the “cells adjacent to each other across the partition walls” means cells adjacent to each other across the partition walls, where the distance between the center points in each cross section is the closest. I mean.

[1-2b] Outflow side opening sealing cell:
In the outflow side opening sealing cell 14b, the plugging portion 18 is disposed from the outflow side end face 34 to a predetermined depth range (the end part 44 on the outflow side end face), and the outflow side end face 34 is disposed. Is a plugged cell 14. Then, in the vicinity of the outflow side end portion 44 where the plugging portion 18 is disposed on at least one surface of the partition wall 12 defining and forming at least one outflow side opening sealing cell 14b, the outflow side opening sealing cell. A communication hole 22 is formed to communicate between 14b and both end opening open cells 14a.

  The communication hole 22 is a total area of the region where the plugging portion 18 is disposed on the outflow side end surface 34 (that is, the outflow side opening sealing cell 14b is plugged in the outflow side end surface 34). The ratio (percentage) of the total area of the openings of all the communication holes 22 formed in the partition walls 12 constituting the honeycomb structure portion 2 to the total area of the openings) is 25 to 100%. Yes. As described above, the communication hole 22 is configured so that the fluid (exhaust gas) that flows into the outflow side opening sealing cell 14b plugged in the outflow side end surface 34 flows into the outflow side and outflow side end surfaces. It is a bypass for moving to the open cell at both ends opened together.

  In addition, the ratio of the total area of the openings of all the communication holes to the total area of the region where the above plugged portions are disposed (hereinafter, referred to as “open ratio of all communication holes (%)”). Is less than 25%, when the catalyst is supported and used as a catalyst body, the amount of exhaust gas passing through the communication hole is remarkably reduced, and it becomes difficult for the exhaust gas to flow into the outflow side opening sealed cell. Only half of the cells (that is, the open cells at both ends) are used for purification, and the purification efficiency is lowered. On the other hand, when the opening ratio (%) of all the communication holes exceeds 100%, the amount of exhaust gas passing through the communication holes increases, and accordingly, the flow velocity in the outflow side opening sealed cell increases. For this reason, the amount of the exhaust gas that passes through the partition wall from the outflow side opening sealed cell and moves to the both-end opening open cell is reduced, and the purification efficiency is remarkably lowered.

  The opening ratio (%) of all the communication holes is set to 25 to 100% as described above in consideration of the balance between the improvement in purification efficiency and the suppression of the increase in pressure loss. The lower limit of the opening ratio (%) is preferably 30%, and more preferably 40%. Further, the upper limit is preferably 90%, and more preferably 80%.

  As long as the communication hole satisfies the range of the open ratio (%) of all the communication holes, one or more cells (for example, one outflow side opening end) among the plurality of outflow side opening sealing cells. (Partial sealing cells) may be formed on at least one surface of the partition wall, and out of all outflow side opening sealing cells, the number of outflow sides is 90% or more (that is, 90 to 100%). It is preferable that the opening sealing cell is formed on at least one surface of the partition wall forming the partition. By comprising in this way, the increase in pressure loss can be suppressed effectively, improving purification efficiency. In addition, considering the balance between the improvement of the purification efficiency and the suppression of the increase in pressure loss, the communication holes are 93 to 100% outflow side opening sealing among all the outflow opening sealing cells. More preferably, it is formed on at least one surface of the partition walls that partition the cells, and particularly preferably formed on at least one surface of the partition walls that partition the outflow side opening-sealed cells as many as 95 to 100%. .

  As for the shape of this communication hole, both the outflow side and outflow side end surfaces of the fluid (exhaust gas) flowing into the outflow side opening sealing cell plugged at the outflow side end surface are opened. The shape is not particularly limited as long as it can be used as a bypass for moving to the open cell at both ends, but it is preferable that the shape of the opening of the communication hole is circular in order to facilitate the formation of the communication hole.

  The “area of the opening of the communication hole (also referred to as the area of the communication hole)” refers to the area of the hole (communication hole) formed in the partition wall. For example, as shown in FIG. When the area of the communication hole 22 in the thickness direction of the partition wall 12 is not constant, the area L of the part where the area of the communication hole 22 is minimum is set as the area of the communication hole 22. Here, FIG. 1E is a cross-sectional view schematically showing another embodiment of the honeycomb structure of the present invention. Note that the cross section shown in FIG. 1E is a cross section showing the same portion as the cross section shown in FIG. 1C.

  The area of the opening portion of the communication hole can be calculated from the diameter of a drill or the like when forming the communication hole and calculated from the hole diameter. For example, as shown in FIG. When the area of the portion is not constant in the thickness direction of the partition wall, the area L of the opening at the minimum portion can be obtained by cutting out the partition wall as necessary.

  The communication hole should just be formed in the at least one surface of the partition which divides and forms the outflow side opening edge part sealing cell. For example, in the honeycomb structure 1 shown in FIGS. 1A to 1D, the shape of the cross section perpendicular to the flow path direction of the cell 14 is a quadrangle, and the four surfaces forming the outflow side opening end sealing cell 14b are partitioned. Although the example in case the communicating hole 22 is formed in two mutually opposing surfaces among the partition walls 12 is shown, for example, like the honeycomb structure 10 as shown in FIGS. 2A to 2C, the outflow side opening The communication holes 22 may be formed in all of the four partition walls 12 that define the end sealing cells 14b. Moreover, although illustration is abbreviate | omitted, the communicating hole may be formed only in the one surface of the partition which divides and forms the outflow side opening edge part sealing cell, for example. Moreover, even when the shape of the cross section perpendicular to the cell flow path direction is a shape other than a quadrangle, it may be formed on at least one surface of the partition wall that defines the outflow side opening end sealing cell.

  Here, FIG. 2A is an enlarged plan view in which an end face on the outflow side of another embodiment of the honeycomb structure of the present invention is enlarged, and FIG. 2B is a schematic diagram schematically showing a CC ′ section of FIG. 2A. FIG. 2C is a schematic cross-sectional view schematically showing a DD ′ cross-section of FIG. 2A. 2A to 2C, the same reference numerals are assigned to the same components as those of the honeycomb structure 1 shown in FIG. 1B, and the description thereof is omitted.

  As shown in FIGS. 1A to 1D, when the cross-sectional shape perpendicular to the flow path direction of the cell 14 is a quadrangle, the four-surface partition walls 12 that partition and form the outflow side opening end sealing cell 14b. Of these, it is preferable that the communication holes 22 are formed on two opposing surfaces or on all four surfaces defining the cell 14.

  Further, the communication hole defines one outflow side opening end sealing cell with respect to the area of the region where the plugging portion is disposed on the outflow side end face of the one outflow side opening end sealing cell. The ratio of the total area of the opening portions of the communication holes formed in the partition wall to be formed (hereinafter, referred to as “opening ratio (%) of communication holes in one outflow side opening end sealing cell)” is 25 to 25 It is preferable that it is formed to be 100%.

  For example, as shown in FIGS. 1A to 1D, communication holes 22 having substantially the same opening size are formed on the two surfaces of the partition wall 12 defining and forming one outflow side opening end sealing cell 14b. In this case, the area of the opening part of one communication hole is 12 with respect to the area of the area where the plugging part 18 is disposed on the end face on the outflow side of one outflow side opening end part sealing cell 14b. 0.5 to 50% (that is, half of the above preferable range of 25 to 100%) is preferable. In addition, in the case where communication holes having different opening areas are respectively formed in the partition walls defining one outflow side opening end sealing cell, the total area of the openings of these communication holes is It is preferable that it is 25 to 100% with respect to the area of the area | region in which the sealing part was arrange | positioned.

  With this configuration, it is possible to efficiently purify harmful substances in the exhaust gas, and to effectively suppress an increase in pressure loss. If the opening ratio (%) of the communication hole in the one outflow side opening end sealed cell is less than 25%, the amount of exhaust gas passing through the communication hole in the outflow side opening end sealing cell is significantly reduced. However, the exhaust gas hardly flows into the outflow side opening sealed cell, and the purification efficiency may be lowered. On the other hand, when the opening ratio (%) of the communication holes in one outflow side opening end sealed cell exceeds 100%, the flow velocity in the outflow side opening sealed cell increases, and the exhaust gas permeating the partition wall is increased. The amount may decrease and the purification efficiency may decrease.

  In addition, the lower limit of the opening ratio (%) of the communication holes in one outflow side opening end sealing cell is more preferably 30%, and particularly preferably 40%. Further, the upper limit is more preferably 90%, and particularly preferably 80%. By comprising in this way, the increase in pressure loss can be suppressed effectively, improving purification efficiency.

  As described above, if the outflow side opening sealed cell is a cell in which the plugging portion is disposed at the end on the outflow side end face side, the flow direction in each outflow side opening sealed cell The areas of the cross sections perpendicular to may not be the same. That is, the outflow side opening sealed cell may be configured by a plurality of cells having different cross-sectional areas and shapes perpendicular to the cell flow path direction, and, of course, all outflow side opening sealed cells. The cross-sectional shapes perpendicular to the flow path direction may be the same.

  In addition, there is no restriction | limiting in particular also about the shape of a cross section perpendicular | vertical to the flow-path direction of an outflow side opening part sealing cell, For example, the shape similar to the preferable cross-sectional shape in the above-mentioned both-ends opening part cell is mentioned as a suitable example. Can do.

  In the case where the communication hole has an outer peripheral wall disposed so as to surround the side surface of the honeycomb structure, more specifically, the outer periphery of the partition wall that defines the cell, the communication hole flows from the outer peripheral wall. It can be formed by continuously drilling holes that penetrate the partition perpendicular to the road direction. When the communication hole is formed by such a method, the communication hole is formed up to the side surface of the honeycomb structure, that is, the outer peripheral wall. Therefore, when the communication hole is formed by such a method, the communication hole is not formed. After the formation, it is preferable to seal the communication hole in the outer peripheral wall with cement or the like. By comprising in this way, a honeycomb structure can be used suitably as a catalyst carrier.

[1-2b-1] Plugging portion:
The plugging portion is a member disposed at the end portion on the outflow side end face side of the outflow side opening sealing cell so as to close the opening portion.

  Such a plugging portion is, for example, for plugging that first includes a material constituting the plugging portion at an end portion on the outflow side end face side of a predetermined cell that becomes an outflow side opening sealing cell. The slurry can be filled, and the opening on the outflow side of the outflow side opening sealed cell can be sealed, dried and fired.

  Although there is no restriction | limiting in particular about the material of a plugging part, For example, the thing similar to a partition etc. can be used suitably.

  Moreover, it is preferable that a plugging part consists of a porous body whose porosity is 20 to 80%. By comprising in this way, the plugging part can also contribute to the purification performance improvement utilizing the surface area of the pores. When the porosity is less than 20%, the surface area of the pores may not be fully utilized. On the other hand, when the porosity exceeds 80%, the mechanical strength of the plugged portion is significantly reduced. May cause damage or the like. The porosity of the plugged portion is more preferably 40 to 75%, and particularly preferably 65 to 75%.

[1-2b-2] Communication hole:
The communication hole is formed in the vicinity of the end on the outflow side where the plugging portion is arranged on at least one surface of the partition wall that defines at least one outflow side opening sealed cell, and both ends. It is a hole formed so as to communicate with the opening part open cell. This communication hole serves as a bypass connecting the outflow side opening sealed cell whose end is closed and the both end opening open cell whose both ends are open, from the outflow side opening sealed cell to the both end opening open cell. The exhaust gas is moved to contribute to the suppression of the increase in pressure loss of the honeycomb structure.

  Such a communication hole is provided in the vicinity of the end portion on the outflow side where the plugging portion is disposed, that is, the cell of the plugging portion disposed on the end portion on the outflow side of the outflow side opening sealing cell. It is formed so as to penetrate the partition wall at a position slightly inside the end surface on the inner side.

  The method for forming the communication hole is not particularly limited. For example, after plugging the end portion on the outflow side of a predetermined cell (outflow side opening sealing cell) of the honeycomb structure portion, the outer peripheral side of the honeycomb structure portion From this, it can be formed by drilling a hole in the partition wall using a piercing member provided with a drill having a diameter similar to the size of the opening of the communication hole.

[2] Manufacturing method of honeycomb structure:
Next, a method for manufacturing the honeycomb structure of the present embodiment (hereinafter, also referred to as “the manufacturing method of the present honeycomb structure”) will be described. As a method of manufacturing the honeycomb structure of the present embodiment, as shown in FIG. 3A, a columnar honeycomb having partition walls 52 that form a plurality of cells 54 that form a ceramic forming raw material and serve as fluid flow paths is formed. Step (1) of obtaining the formed body 72, and as shown in FIG. 3B, filling the plugging slurry 86 into the opening of a predetermined cell 54b on one end face 84 side of the obtained honeycomb formed body 72, Step (2) of obtaining a plugged honeycomb formed body 74 in which openings of predetermined cells 54b are plugged, and firing the obtained plugged honeycomb formed body 74 as shown in FIG. A step (3) of obtaining a plugged honeycomb fired body 76 in which the plugged portions 64 are disposed in the openings of the cells 54b, and as shown in FIGS. 3D and 3E, From the outer peripheral surface side, the cell in which the plugging portion 64 is disposed is A step of obtaining the honeycomb structure 71 of the present embodiment by forming the communication hole 66 at a position slightly inside the end face on the inner side of the cell of the plugging portion 64 on at least one surface of the partition wall 52 to be formed ( And 4).

  Here, FIGS. 3A to 3E are explanatory views showing a method of manufacturing an embodiment of the honeycomb structure of the present invention. 3A shows the step (1), FIG. 3B shows the step (2), FIG. 3C shows the step (3), and FIGS. 3D and 3E show the step (4). 3D is a plan view of the honeycomb structure as viewed from above, and FIG. 3E is an enlarged side view of the honeycomb structure as viewed from the side.

  Thus, in the manufacturing method of the present honeycomb structure, as shown in FIG. 3B and FIG. 3C, the predetermined cells 54b to be plugged and the cells adjacent to each other with the partition wall 52 (the remaining cells 54a), A mask 68 that covers the opening on one end face 84 side of the adjacent cell 54a is disposed, and only a predetermined cell 54b is filled with the plugging slurry 86 and plugged, and then the obtained plugging is obtained. The honeycomb formed body 74 is fired to obtain a plugged honeycomb fired body 76, and then, as shown in FIGS. 3D and 3E, at least one surface of the partition wall that partitions the cells in which the plugging portions 64 are disposed. The honeycomb structure 71 is manufactured by forming the communication holes 66 in the honeycomb structure 71.

  By comprising in this way, the honeycomb structure 1 as shown to FIG. 1A and FIG. 1B can be manufactured simply and at low cost. In the manufacturing method of the present honeycomb structure, the above-described predetermined cell 54b (see FIG. 3E) forms the outflow side opening sealing cell 14b, and the remainder in which the mask 68 (see FIG. 3B) is disposed in the opening. The open cell 14a at both ends is formed by the cell 54a (see FIG. 3E). One end face 84 (see FIG. 3B) filled with the plugging slurry becomes the end face 34 on the outflow side of the honeycomb structure, and the opposite end face (the other end face 82 (see FIG. 3B)) flows in. It becomes the end face 32 on the side.

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

[2-1] Step (1):
In the step (1), as shown in FIG. 3A, a columnar honeycomb formed body 72 having partition walls 52 that form a plurality of cells 54 to be fluid flow paths by forming a ceramic forming raw material containing a ceramic raw material. It is the process of obtaining. This step (1) can be performed according to a conventionally known method for manufacturing a honeycomb structure.

[2-2] Step (2):
In the step (2), as shown in FIG. 3B, the plugging slurry 86 is filled in the opening of the predetermined cell 54b on the one end face 84 side of the obtained honeycomb formed body 72, and the predetermined cell 54b. This is a step of obtaining a plugged honeycomb formed body 74 whose openings are plugged with plugging portions 64.

  In the method for manufacturing the honeycomb structure, the remaining cells 54b that are plugged and the remaining cells 54a that are not plugged are alternately arranged, for example, with a partition wall therebetween. A mask 68 that covers the opening on the one end face 84 side of the cell 54a is provided, and only a predetermined cell 54b is filled with the plugging slurry 86.

  By configuring in this way, in the obtained honeycomb structure, the both-end opening open cells and the outflow side opening sealing cells are alternately arranged with the partition walls therebetween, and the honeycomb structure of the present invention is arranged. It becomes possible to manufacture efficiently.

  The method of disposing the mask 68 on the remaining cells 54a is not particularly limited. For example, the adhesive film 68a is attached to the entire one end face 84 of the honeycomb formed body 72, and the adhesive film 68a is attached. For example, a method of making a hole in a part (that is, a part corresponding to the opening of the predetermined cell 54b without a mask) can be used. More specifically, only the portion corresponding to the cell (predetermined cell 54b) in which the plugged portion 64 is to be formed after the adhesive film 68a is adhered to the entire one end face 84 of the honeycomb formed body 72. A method of opening a hole with a laser can be suitably used. As the adhesive film 68a, a film in which an adhesive is applied to one surface of a film made of a resin such as polyester, polyethylene, or a thermosetting resin can be suitably used.

  Examples of the plugging slurry for forming the plugged portion include a slurry in which the ceramic raw material and the additive used for obtaining the honeycomb formed body described above 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.

[2-3] Step (3):
In the step (3), as shown in FIG. 3C, the obtained plugged honeycomb formed body 74 is fired, and the plugged honeycomb in which the plugged portions 64 are disposed in the openings of the predetermined cells 54b. This is a step of obtaining a fired body 76. This step (3) can be performed according to a conventionally known method for manufacturing a honeycomb structure.

[2-4] Step (4):
In step (4), as shown in FIGS. 3D and 3E, from the outer peripheral surface side of the obtained honeycomb fired body 76, at least one surface of the partition wall that partitions the cells in which the plugging portions 64 are disposed, In this step, the communication hole 66 is formed at a position slightly inside the end surface of the plugged portion 64 on the inner side of the cell, thereby obtaining the honeycomb structure 71 of the present embodiment. By comprising in this way, the honeycomb structure 1 of this embodiment as shown to FIG. 1A-FIG. 1D can be manufactured simply and at low cost.

  In the case of forming the communication hole, from the outer peripheral surface side of the honeycomb fired body 76, using a drilling member 88 provided with a drill having a diameter similar to the size of the opening of the communication hole 66 to be formed, A method of forming a hole at a position slightly inside the end face on the inner side of the cell of the plugged portion 64 can be mentioned. In the method for manufacturing the honeycomb structure, the ratio of the total area of the openings of all the communication holes to the total area of the region where the plugging portions are disposed on the end surface on the outflow side is 25 to 100%. The communication hole is formed so that

  The piercing member 88 for forming the communication hole includes, for example, a drill 88a longer than the diameter of the end face of the honeycomb fired body 76, and drills perpendicular to the axial direction of the honeycomb fired body 76 (that is, the cell flow path direction). 88a is preferably pressed to form a communication hole penetrating from one side surface of the honeycomb fired body 76 to the opposite side surface.

  In addition, there is no restriction | limiting in particular about the method of forming a communicating hole, You may form by methods other than the piercing member provided with the above-mentioned drill.

  Further, when the communication hole is formed by the above method, the communication hole is also formed on the outer peripheral side of the honeycomb structure, and thus the communication hole is formed even on the outer peripheral side of the honeycomb structure. In some cases, it is preferable to seal the communication hole on the outer peripheral side with cement or the like.

[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 (for example, the honeycomb structure 1 shown in FIG. 1A) and the honeycomb structure. A honeycomb catalyst body including a catalyst supported on the partition wall surface.

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 an end surface on the inflow side, and then a predetermined cell (outflow side). Exhaust gas flowing into the opening sealing cell) is permeated through the partition wall to purify harmful substances such as carbon monoxide (CO), hydrocarbon (HC), nitrogen oxide (NO _x ) with a catalyst. is there. The permeated fluid (purified gas) that has permeated through the partition wall in this manner flows out from the opening on the end face on the outflow side of an adjacent cell (both-end opening open cell).

  In the honeycomb catalyst body of the present embodiment, the opening portion of the cell on the inflow side end face of the outflow side opening portion sealing cell seals the plugging portion, and the vicinity of the outflow side end portion where the plugging portion is disposed. In the partition wall, a communication hole communicating with the adjacent open cell at both end openings is formed, so that a part of the fluid flowing into the outflow side opening sealing cell is transmitted through the partition wall (open at both end openings). The fluid that has not passed through the partition wall can be moved to an adjacent cell by a communication hole formed in the vicinity of the end on the outflow side, and the fluid can be discharged from the end surface on the outflow side. it can. At this time, when the partition wall and the fluid come into contact with each other and when the fluid permeates the partition wall, harmful substances contained in the exhaust gas 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 the inflow side end face of the outflow side opening sealing cell is sealed with a plugging portion. However, since a communication hole communicating with the open cell at both ends of the opening is formed, even if the exhaust gas purification efficiency is improved as described above, the increase in pressure loss is effectively suppressed, or the pressure loss is reduced. 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 improvement of exhaust gas purification efficiency and suppression of increase in pressure loss.

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 Further, those containing at least one kind of palladium (Pd), further containing activated alumina and ceria as an oxygen storage agent are preferable. 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 catalyst loading is more preferably 150 to 200 g, and particularly preferably 160 to 180 g, per liter 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. The ratio between the amount of catalyst supported on the inner surface of the pores of the partition walls and the amount of catalyst supported on the partition wall surfaces can be simplified by comparing the cross-sectional areas of the cross-sectional microstructure images of the partition walls. Can be evaluated.

[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.

  First, a honeycomb structure as a 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 is manufactured according to the method of manufacturing the honeycomb structure of the present embodiment described above. Can do.

  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, after the honeycomb structure is wash-coated with a catalyst solution containing a catalyst component, it can be heat treated at a high temperature and baked.

  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.

[Opening ratio (%) of all communication holes]: The total of the openings of all the communication holes formed in the partition walls with respect to the total area of the region where the plugging portions are disposed on the end face on the outflow side of the honeycomb structure. The area ratio (percentage) was defined as the opening ratio (%) of all communication holes.

[Catalyst loading (g / L)]: The catalyst loading (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.

[Pressure loss (kPa)]: A predetermined amount of 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 difference was taken as pressure loss (kPa). Measurements of the pressure, the flow rate of the measurement gas, from 0.92 nm ³ / min until 9.91Nm ³ / min, to increase the flow rate by about ^{1 Nm} 3 / min, it 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) and nitrogen oxide (NO _x ) in the exhaust gas was measured. In addition, 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.

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 30-45% by weight, 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”.

  Next, outflow of the obtained honeycomb formed body so that the end face on the outflow side has a checkered pattern (that is, a staggered pattern) at the opening of the cell on one end face side corresponding to the end face on the outflow side. A plugged portion was formed at the end of a predetermined cell corresponding to the side opening plugged cell to obtain a plugged honeycomb formed body. In addition, the arrangement | positioning depth of the plugging part was 3 mm from the end surface of the honeycomb molded body. As the plugging slurry for forming the plugged portion, the cordierite forming raw material prepared in the same proportion as the cordierite forming raw material used for the above-mentioned honeycomb molding forming clay, water, binder, pore formation The slurry which mix | blended additives, such as material and surfactant, and adjusted the viscosity to 150-400 dPa * s was used. In addition, the remaining cell in which the plugging portion is not formed becomes a both-end opening open cell.

Next, the obtained plugged honeycomb formed body is fired at 1400 ° C., and at least one surface of the partition wall of the obtained plugged honeycomb fired body partitioning and forming at least one outflow side opening sealed cell In the vicinity of the end on the outflow side where the plugging portion is disposed, the outflow side opening sealing cell and the both end opening open cell communicate with each other, and the opening forms a circular communication hole, A honeycomb structure of the present invention was manufactured. In this example, the communication holes were drilled so that the opening ratio (%) of all the communication holes was 25%. Table 1 shows the partition wall thickness (μm), cell density (cell / cm ² ), average pore diameter (μm), and porosity (%) of the honeycomb structure. In the examples, communication holes were formed on two opposing surfaces of the partition wall. The honeycomb structures manufactured in each of the examples and comparative examples have a cylindrical shape with an end face diameter of 105.7 mm and an axial length of 114.3 mm in all the examples and comparative examples. About what arrange | positioned the sealing part, the arrangement | positioning depth was 3 mm.

Next, the obtained honeycomb structure includes γ-alumina supporting a platinum group metal prepared such that the ratio of platinum (Pt) to rhodium (Rh) (Pt: Rh) is 5: 1. A catalyst was supported so that the amount of catalyst supported was 160 g / L, and a honeycomb catalyst body was manufactured (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 measurement of pressure loss and the amount of harmful component discharge were measured. Table 2 shows the measurement results of pressure loss, and Table 3 shows the measurement results of harmful component discharge. FIG. 4 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). 5 and 6 are graphs showing the measurement results of the harmful component discharge amount, the horizontal axis represents the platinum group metal loading (g / L), and the vertical axis represents the harmful component discharge amount (g / mile). Indicates. FIG. 5 shows the results of measuring hydrocarbons (HC) as harmful components, and FIG. 6 shows the results of measuring nitrogen oxides (NO _x ) as harmful components.

(Examples 2 to 4)
Except for changing the opening ratio (%) of all the communication holes as shown in Table 1, a honeycomb structure configured in the same manner as in Example 1 was manufactured. A catalyst was supported by the same method as in Example 1 to produce honeycomb catalyst bodies (Examples 2 to 4). About each honeycomb catalyst body of Examples 2-4, the measurement of the above-mentioned pressure loss and the measurement of harmful component discharge | emission amount were performed. The results are shown in Tables 2 and 3.

(Comparative Example 1)
A honeycomb structure having a partition wall thickness (μm), a cell density (cell / cm ² ), an average pore diameter (μm), and a porosity (%) as shown in Table 1 was manufactured and obtained. As shown in Table 1, a catalyst was supported on the honeycomb structure so that the catalyst loading was 200 g / L, and a honeycomb catalyst body was manufactured (Comparative Example 1). The honeycomb structure of Comparative Example 1 was obtained by removing the pore former from the raw material from which the honeycomb structure of Example 1 was manufactured. With respect to the obtained honeycomb catalyst body of Comparative Example 1, the above-described pressure loss measurement and harmful component discharge amount measurement were performed. The results are shown in Tables 2 and 3.

(Comparative Example 2)
Except for changing the opening ratio (%) of all the communication holes as shown in Table 1, a honeycomb structure configured in the same manner as in Example 1 was manufactured. A honeycomb catalyst body was manufactured by supporting the catalyst in the same manner as in Example 1 (Comparative Example 2). The honeycomb catalyst body of Comparative Example 2 was measured for the pressure loss and the harmful component discharge amount described above. The results are shown in Tables 2 and 3.

(Result 1)
As shown in Table 2 and FIG. 4, in the measurement of pressure loss, the honeycomb catalyst body of Example 1 showed a higher value than that of Comparative Example 1 at a measurement gas flow rate of 5 m ³ / min or more. Examples 2-4 showed the value lower than the comparative example 1 to 10 m < ³ > / min. When compared at 8 Nm ³ / min, in Example 2, it was confirmed that the pressure loss was reduced by about 10%.

  Further, as shown in Table 3, FIG. 5 and FIG. 6, in the measurement of the harmful component discharge amount, in the honeycomb catalyst bodies of Examples 1 to 4, the purification performance improves as the opening ratio of all the communication holes decreases. However, when the opening ratio of all the communication holes is reduced to 10% as in Comparative Example 2, the exhaust gas is not sufficiently moved through the communication holes, and only about half of the cells are used for purification, and harmful components are present. It was confirmed that emissions increased significantly.

  FIG. 7 shows the relationship between pressure loss and harmful component emissions (hydrocarbon (HC) emissions). In FIG. 7, the ratio of each Example 1-4 and the comparative example 2 with respect to the pressure loss and harmful component discharge | emission amount of the comparative example 1 is shown, and a horizontal axis shows the pressure loss of the comparative example 1 1. The vertical axis represents the ratio when the harmful component discharge amount of Comparative Example 1 is 1.

  As shown in FIG. 7, the honeycomb catalyst bodies of Examples 1 to 4 exceeded the trade-off line X 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 and It was possible to achieve both the trade-off of 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 5 to 7 and Comparative Examples 3 and 4)
Except for changing the average pore diameter (μm) as shown in Table 4, a honeycomb structure having the same configuration as in Example 2 (opening ratio of all communication holes 50%) was manufactured and obtained. A catalyst was supported on the honeycomb structure by the same method as in Example 1 to manufacture honeycomb catalyst bodies (Examples 5 to 7 and Comparative Examples 3 and 4). With respect to each of the honeycomb catalyst bodies of Examples 5 to 7 and Comparative Examples 3 and 4, the above-described pressure loss measurement and harmful component discharge amount were measured. The results are shown in Tables 5 and 6. FIG. 8 is a graph showing the measurement result of the pressure loss, where the horizontal axis indicates the flow rate (Nm ³ / min) of the measurement gas, and the vertical axis indicates the pressure loss (kPa). FIG. 9 and FIG. 10 are graphs showing the measurement results of the harmful component emission amount, the horizontal axis shows the platinum group metal loading (g / L), and the vertical axis shows the harmful component emission amount (g / mile). Indicates. 9 shows the result of measuring hydrocarbon (HC) as a harmful component, and FIG. 10 shows the result of measuring nitrogen oxide (NO _x ) as a harmful component.

(Result 2)
As shown in Table 5 and FIG. 8, in the measurement of the pressure loss, the honeycomb catalyst bodies of Examples 5 to 7 showed lower values than the honeycomb catalyst body of Comparative Example 1.

  Further, as shown in Table 6, FIG. 9 and FIG. 10, it was found that the average pore diameter has an optimum value in the measurement of the harmful component discharge amount, and there is an optimum value in the vicinity of 20 μm of Example 6. That is, when the average pore diameter is smaller than 15 μm as in Comparative Example 3, the pores of the partition walls are blocked, the pore surface area cannot be used, and the harmful component discharge amount is greatly increased. Further, when the average pore diameter is larger than 70 μm as in Comparative Example 4, the surface area due to the pores in the partition walls is remarkably reduced, and the harmful component discharge amount is greatly increased.

  FIG. 11 shows the relationship between pressure loss and harmful component emissions (hydrocarbon (HC) emissions). In FIG. 11, the ratio of each Example 5-7 and the comparative examples 3 and 4 with respect to the pressure loss and harmful component discharge | emission amount of the comparative example 1 is shown, and a horizontal axis shows the pressure of the comparative example 1. This is the ratio when the loss is 1, and the vertical axis is the ratio when the harmful component discharge amount of Comparative Example 1 is 1.

  As shown in FIG. 11, the honeycomb catalyst bodies of Examples 5 to 7 exceed the trade-off line in which a reduction of 10% is confirmed with respect to the pressure loss and harmful component discharge amount of Comparative Example 1, and the pressure loss and purification It was possible to achieve both the trade-off of performance.

(Examples 8 to 10 and Comparative Examples 5 and 6)
A honeycomb structure manufactured by manufacturing a honeycomb structure configured in the same manner as in Example 2 (opening ratio of all communication holes 50%) except that the porosity (%) was changed as shown in Table 7 was obtained. Catalysts were supported on the structure by the same method as in Example 1 to manufacture honeycomb catalyst bodies (Examples 8 to 10 and Comparative Examples 5 and 6). With respect to each of the honeycomb catalyst bodies of Examples 8 to 10 and Comparative Examples 5 and 6, the pressure loss measurement and the harmful component discharge amount were measured. The results are shown in Table 8 and Table 9. FIG. 12 is a graph showing the measurement result of the pressure loss, where the horizontal axis indicates the flow rate of the measurement gas (Nm ³ / min), and the vertical axis indicates the pressure loss (kPa). FIG. 13 and FIG. 14 are graphs showing the measurement results of the harmful component discharge amount, the horizontal axis represents the platinum group metal loading (g / L), and the vertical axis represents the harmful component discharge amount (g / mile). Indicates. FIG. 13 shows the result of measuring hydrocarbon (HC) as a harmful component, and FIG. 14 shows the result of measuring nitrogen oxide (NO _X ) as a harmful component.

(Result 3)
As shown in Table 8 and FIG. 12, in the measurement of pressure loss, the honeycomb catalyst bodies of Examples 8 to 10 showed lower values than the honeycomb catalyst body of Comparative Example 1.

  Moreover, as shown in Table 9, FIG. 13 and FIG. 14, it was found that the porosity has an optimum value in the measurement of the harmful component discharge amount, and there is an optimum value in the vicinity of 65 to 80% of Example 10. . That is, when the porosity is smaller than 50% as in Comparative Example 5, the pore surface area of the partition walls is reduced, and the harmful component discharge amount is greatly increased. Further, when the porosity is larger than 80% as in Comparative Example 6, although the harmful component discharge amount is the lowest, the strength is lowered, so that it is considered that it is not suitable for application to an actual vehicle.

  FIG. 15 shows the relationship between pressure loss and harmful component emissions (hydrocarbon (HC) emissions). In FIG. 15, the ratios of Examples 8 to 10 and Comparative Examples 5 and 6 with respect to the pressure loss and harmful component discharge amount of Comparative Example 1 are shown, and the horizontal axis represents the pressure of Comparative Example 1. This is the ratio when the loss is 1, and the vertical axis is the ratio when the harmful component discharge amount of Comparative Example 1 is 1.

  As shown in FIG. 15, the honeycomb catalyst bodies of Examples 8 to 10 exceed the trade-off line where a 10% reduction is confirmed with respect to the pressure loss and harmful component discharge amount of Comparative Example 1, and the pressure loss and purification It was possible to achieve both the trade-off of performance.

  From the comparison between the honeycomb catalyst bodies of Examples 1 to 10 and Comparative Example 1 which is a conventional catalyst body, the honeycomb catalyst body of the present invention can reduce the amount of noble metal used for the catalyst by improving the purification efficiency. The possibility that it could be reduced by at least 20% was shown.

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. 1B is an enlarged plan view in which an end face on the outflow side of the honeycomb structure shown in FIG. 1A is enlarged. It is a schematic sectional drawing which shows typically the A-A 'cross section of FIG. 1B. It is a schematic sectional drawing which shows typically the B-B 'cross section of FIG. 1B. It is sectional drawing which shows typically other embodiment of the honeycomb structure of this invention. It is the enlarged plan view which expanded the end face of the outflow side of other embodiments of the honeycomb structure of the present invention. It is a schematic sectional drawing which shows typically the C-C 'cross section of FIG. 2A. It is a schematic sectional drawing which shows the D-D 'cross section of FIG. 2A typically. It is explanatory drawing which shows the method of manufacturing one Embodiment of the honeycomb structure of this invention, and is explanatory drawing explaining a process (1). It is explanatory drawing which shows the method of manufacturing one Embodiment of the honeycomb structure of this invention, and is explanatory drawing explaining a process (2). It is explanatory drawing which shows the method of manufacturing one Embodiment of the honeycomb structure of this invention, and is explanatory drawing explaining a process (3). It is explanatory drawing which shows the method of manufacturing one Embodiment of the honeycomb structure of this invention, and is explanatory drawing explaining a process (4). It is explanatory drawing which shows the method of manufacturing one Embodiment of the honeycomb structure of this invention, and is explanatory drawing explaining a process (4). 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. 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

DESCRIPTION OF SYMBOLS 1,10: Honeycomb structure, 2: Honeycomb structure part, 12: Partition, 14: Cell, 14a: Opening opening part cell of both ends, 14b: Outflow side opening sealing cell, 16: Outer peripheral wall, 18: Plugging Part 22: communication hole 32: end face on the inflow side 34: end face on the outflow side 44: end part on the outflow side 52: partition wall 54: cell 54a: cell (remaining cell) 54b: cell ( (Predetermined cell), 64: plugging portion, 66: communication hole, 68: mask. 68a: adhesive film, 71: honeycomb structure, 72: honeycomb formed body, 74: plugged honeycomb formed body, 76: plugged honeycomb fired body, 82: the other end face, 84: one end face, 86: eye Sealing slurry, 88: perforated member, 88a: drill, L: area of the communication hole (area of the part where the area of the communication hole is minimum).

Claims (6)

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,
The plurality of cells include open-ended open-ended cells each having an area of a cross-section perpendicular to the flow direction of the cells from the end surface on the inflow side to the end surface on the outflow side, and the cell. An outflow side opening sealing cell provided with a plugging portion for sealing an end portion of a predetermined length from the end surface on the outflow side, and at least one outflow side opening sealing cell is , The both-end opening open cell and the partition are arranged,
The partition wall is sealed at the outflow side opening portion in the vicinity of the end portion on the outflow side where the plugging portion is disposed on at least one surface of the partition wall that defines at least one outflow side opening portion sealing cell. A communication hole is formed to communicate the stop cell and the both-end opening open cell,
In the communication hole, the ratio of the total area of the openings of all the communication holes to the total area of the region where the plugging portions are disposed on the end surface on the outflow side is 25 to 100%. The communication hole is formed in the one outflow side opening end with respect to the area of the region where the plugging portion is disposed on the outflow side end face of one outflow side opening end portion sealing cell. A honeycomb structure formed such that the ratio of the total area of the opening portions of the communication holes formed in the partition walls forming the partial sealing cells is 25 to 100% .   2. The honeycomb structure according to claim 1, wherein the both-end opening open cells and the outflow side opening sealed cells are alternately arranged with the partition walls therebetween. The honeycomb structure according to claim 1 or 2 , wherein the communication hole has a circular opening. Of all of the outlet aperture sealing the cells, at least one surface of the partition walls defining a number of outlet aperture sealing cells of 90% or more, of claims 1-3, wherein the communication hole is formed The honeycomb structure according to any one of claims. A honeycomb structure according to any one of claims 1 to 4 , and a catalyst supported on the inner surface of the pores of the partition walls of the honeycomb structure and the catalyst supported on the partition surface. Honeycomb catalyst body. The honeycomb catalyst body according to claim 5 , wherein 100 to 250 g of the catalyst is supported per 1 L of the volume of the honeycomb structure.

Images