JP5368770B2 - Honeycomb structure, manufacturing method thereof, and honeycomb catalyst body - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a honeycomb structure for efficiently removing toxic substances contained in exhaust gas by carrying a catalyst and for effectively restraining the increase of a pressure loss. <P>SOLUTION: The honeycomb structure 1 is provided with a columnar honeycomb structure part 2 having porous partition walls 12 for dividing/forming a plurality of cells 14. The partition wall 12 has a porosity of 50-80% and an average pore size of 13-70 &mu;m. The plurality of cells 14 include a first cell 14a formed to have a fixed area in the cross section perpendicular to the flow path direction of the cell 14 and a second cell 14b in which an open area reducing member 18 is arranged for plugging a part of an opening thereof and which is formed to have a reduced area in the cross section perpendicular to the flow path direction of the cell 14 at the end of the cell on the outflow-side end face 34 side. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

The present invention relates to a honeycomb structure, a manufacturing method thereof, 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. Honeycomb structure capable of efficiently purifying harmful substances such as nitrogen oxide (NO _x ) and effectively suppressing an increase in pressure loss, and manufacturing method thereof, and the honeycomb structure The present invention relates to a honeycomb catalyst body on which a catalyst is supported.

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 It is an object of the present invention to provide a honeycomb structure capable of effectively suppressing an increase in the number of particles, a manufacturing method thereof, and a honeycomb catalyst body in which a catalyst is supported on the honeycomb structure.

  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, An opening area reducing member is provided to open all the cell openings on the inflow side end face, and to reduce the opening area of the outflow side end face only to specific cells on the outflow side end face. By configuring the fluid (exhaust gas) flowing into the cell in which the area reducing member is disposed to preferentially permeate the partition walls defining the specific cell and to flow out to the adjacent cells, The present invention was completed by conceiving that the problems could be solved. Specifically, according to the present invention, the following honeycomb structure, a manufacturing method thereof, and a 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 opening area reducing member is arranged in the opening of the end portion on the outflow side end face side so as to block a part of the opening portion, and the first cell having a uniform cross-sectional area. It is set, and the second cell area of the cross section perpendicular to the flow direction of the cell at the end of the end face of the outlet side is formed so as to reduce a honeycomb structure comprising at least The second cell is separated from the first cell by a partition wall. The second cell has an area of the opening before a part of the opening is blocked by the opening area reducing member, the sum of the areas of the openings on the end face on the outflow side. The second cell is formed so that a ratio of the area of the opening on the end surface on the outflow side of the opening is reduced by the opening area reducing member. The honeycomb structure formed so that the ratio with respect to the area of the opening before the portion is blocked is 20 to 95% .

[ 2 ] In the second cell, the area of the cross section perpendicular to the flow direction of the cell in the portion where the opening area reducing member is not disposed is the area of the cross section perpendicular to the flow direction of the first cell. The honeycomb structure according to [1 ], wherein the honeycomb structure is formed so as to be the same.

[ 3 ] The honeycomb structure according to [1] or [2] , wherein the opening area reducing member is made of a porous body having a porosity of 20 to 80%.

[ 4 ] The honeycomb structure according to any one of [1] to [ 3 ], wherein the number of the second cells is 45 to 50% with respect to the total number of the plurality of cells.

[ 5 ] The honeycomb structure according to any one of [1] to [ 4 ], wherein the opening area reducing member is formed by acid treatment.

[ 6 ] The honeycomb structure according to any one of [1] to [ 4 ], wherein the opening area reducing member is formed of a catalyst material.

[ 7 ] The honeycomb structure according to any one of [1] to [ 6 ], a catalyst supported on the inner surface of the pores of the partition walls of the honeycomb structure, and a catalyst supported on the surface of the partition walls; And a honeycomb catalyst body.

[ 8 ] The honeycomb catalyst body according to [ 7 ], wherein the catalyst is supported in an amount of 100 to 250 g per 1 L of the volume of the honeycomb structure.

[ 9 ] A step (1) of forming a ceramic forming raw material to obtain a columnar honeycomb formed body having partition walls for partitioning and forming a plurality of cells serving as fluid flow paths, and one of the obtained honeycomb formed bodies A step (2) of obtaining a plugged honeycomb formed body in which openings of predetermined cells on the end surface side are filled with a plugging slurry to plug the openings of the predetermined cells; A through-hole penetrating from the one end surface side to the inside of the plugged cell is drilled in the plugged portion of the sealed honeycomb formed body, and the area of the opening portion of the predetermined cell on the one end surface side the honeycomb structure but that includes the step (3) to obtain an opening area reduced honeycomb formed body obtained by reducing a step (4) firing the resulting said opening area reduced honeycomb formed body to obtain a honeycomb structure, the obtained Multiple cells of the body are the end faces on the inflow side The first cell in which the area of the cross section perpendicular to the flow path direction of the cell extends from the cell to the end surface on the outflow side, and the opening in the end portion on the end surface side on the outflow side. An opening area reducing member is disposed so as to block a part of the portion, and a second cross section perpendicular to the flow path direction of the cell is reduced at the end on the outflow side end face side. And at least the second cell is disposed adjacent to the first cell with a partition wall therebetween, and the second cell is an end face on the outflow side. The ratio of the sum of the areas of the openings to the sum of the areas of the openings before the openings are partially closed by the opening area reducing member is 20 to 95%, and , The second cell is the end surface on the outflow side. Of the area of the mouth, the ratio to the area of the opening of the front part of the opening portion by the opening area reduction member is closed The production method 20-95 percent composed so formed with have a honeycomb structure .

[ 10 ] In the step (2), a mask that covers the opening on the one end face side of the adjacent cell is disposed on the adjacent cell across the partition wall with the predetermined cell to be plugged. The method for manufacturing a honeycomb structured body according to [ 9 ], wherein only the predetermined cells are filled with the plugging slurry.

  The honeycomb structure and the honeycomb catalyst body of the present invention have a honeycomb structure including a honeycomb structure portion having a porous partition wall having a specific porosity and an average pore diameter. Since the area of the portion is reduced by the opening area reducing member, a part of the fluid that has flowed into the second cell is allowed to pass through the partition walls that define the second cell and enter the adjacent first cell. The exhaust gas can be actively discharged, and the harmful substances contained in the exhaust gas can be efficiently purified.

  Further, the honeycomb structure and the honeycomb catalyst body of the present invention have a partition wall porosity and an average pore diameter in a specific range, and in the second cell, although the area of the opening is reduced, Since a part of the fluid can flow out from the reduced opening (that is, the opening is not completely sealed), even if the exhaust gas purification efficiency is improved as described above, the pressure An increase in 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.

  Moreover, the honeycomb structure manufacturing method of the present invention can manufacture the above-described honeycomb structure of the present invention simply and at low cost.

  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. FIG. 1C is a schematic cross-sectional view schematically showing the AA ′ cross-section of FIG. 1B.

  As shown in FIGS. 1A to 1C, the honeycomb structure 1 of the present embodiment has a porous partition wall 12, and the partition wall 12 penetrates from an end surface 32 on the inflow side to an 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 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 can be purified with a catalyst.

  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, in the honeycomb structure 1 of the present embodiment, the plurality of cells 14 defined by the partition walls 12 have a cross-sectional area 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. An opening area reducing member 18 is disposed in the opening portion at the end portion on the outflow side end surface 34 side of the first cell 14a formed to have a constant size so as to block a part of the opening portion. And the second cell 14b formed so that the area of the cross section perpendicular to the flow path direction of the cell 14 is reduced at the end on the side end face 34 side. In the honeycomb structure 1 of the present embodiment, at least a second cell 14b is that is disposed adjacent to the first cell 14a at a partition wall 12.

  Thus, in the honeycomb structure 1 of the present embodiment, all the openings in the inflow side end face 32 of all the cells 14 are opened, and specific cells (FIG. 1A to FIG. In the honeycomb structure 1 shown in FIG. 1C, the opening area reducing member 18 that reduces the opening area of the end surface 34 on the outflow side is provided in the second cell 14b), and the opening area reducing member 18 is provided. The fluid that has flowed into the formed cell (second cell 14b) can be allowed to actively flow out to the adjacent first cell 14a through the partition wall 12 defining the second cell 14b. It is configured. 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 particular, when at least the second cell is disposed adjacent to the first cell across the partition wall, the amount (flow rate) of fluid that permeates the partition wall can be increased efficiently, Gas purification efficiency can be improved effectively.

  In the honeycomb structure 1 of the present embodiment, although the area of the opening of the second cell 14b is reduced by the opening area reducing member 18, a part of the fluid can flow out from the reduced opening. (Ie, the opening of the second cell 14b is not completely sealed), so that even if the exhaust gas purification efficiency is improved as described above, the increase in pressure loss is effectively suppressed, or Pressure loss can be reduced.

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

  In addition, when not all the cells adjacent to the first cell are the second cells, for example, one of the cells adjacent to the first cell is the first cell (that is, the first cells are adjacent to each other). The first cell from which the fluid has flowed through the partition wall from the second cell (for example, the first cell). The fluid further moves to another first cell adjacent to the cell and the partition wall, and the movement of the fluid between the cells continuously occurs, so that the exhaust gas purification performance can be improved.

[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 has an outer peripheral wall disposed so as to surround the outer periphery of the partition wall that partitions 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.

  If the porosity of the partition walls is less than 50%, even if the above-described second cell configuration is adopted, the porosity of the partition walls is too low, and the pore surface area of the partition walls is reduced, resulting in purification efficiency. It is impossible to achieve both the effect of improving the pressure and the effect of suppressing the increase in pressure loss. 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 arranged so as to surround the partition wall is not particularly limited, but for example, a circle, an ellipse, an ellipse, a trapezoid , Triangles, quadrangles, hexagons, or left-right asymmetrical irregular shapes. 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, the average pore diameter is 13 to 70 μm, and the plurality of cells defined by the partition walls have a constant cross-sectional area perpendicular to the flow direction of the cells from the end surface on the inflow side to the end surface on the outflow side. An opening area reducing member is disposed in the opening of the first cell formed at the end and the end of the end face on the outflow side so as to block a part of the opening, and the end on the end face side of the outflow side By including the second cell formed so that the area of the cross section perpendicular to the cell flow path direction is reduced in the part, the exhaust gas purification efficiency can be effectively improved.

[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, 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.

  As shown in FIGS. 1A to 1C, in the honeycomb structure 1 of the present embodiment, the plurality of cells 14 have a cross section perpendicular to the cell flow direction from the end surface 32 on the inflow side to the end surface 34 on the outflow side. An opening area reducing member 18 is disposed in the opening portion at the end portion on the outflow side end face 34 side so as to block a part of the opening portion in the first cell 14a having a constant area. And a second cell 14b formed so that the area of the cross section perpendicular to the cell flow path direction is reduced at the end portion on the outflow side end face 34 side.

In the honeycomb structure of the present embodiment, at least a second cell 14b is that is disposed adjacent to the first cell 14b by partition walls. That is, in the honeycomb structure 1 of the present embodiment, at least the cells 14 adjacent to the second cells 14b are all the first cells 14b, and the second cells 14b are adjacent to each other across the partition wall 12. that is configured so that there is no. Since the area of the cross section perpendicular to the cell flow path direction is reduced at the end portion on the outflow side end surface 34 side of the second cell 14b, when exhaust gas flows from the opening of the end surface 32 on the inflow side, As it moves to the end surface 34 on the outflow side, the flow rate of the exhaust gas decreases and the pressure in the second cell 14b also increases. On the other hand, since the first cell 14a has a cross-sectional area perpendicular to the cell flow path direction from the end surface 32 on the inflow side to the end surface 34 on the outflow side, the above-described second cell 14b. As compared with the above, the increase in pressure on the end surface 34 side on the outflow side is reduced. For this reason, the exhaust gas flowing into the second cell 14b moves through the partition 12 into the first cell 14a where the pressure in the cell is relatively low. Purification with a catalyst is effectively performed.

[1-2a] First cell:
The first cell 14a is a cell 14 in which the area of a cross section perpendicular to the flow path direction of the cell 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 first cells need only have a cross-sectional area perpendicular to the cell flow path direction from the end surface on the inflow side to the end surface on the outflow side in each first cell. The areas of the cross sections perpendicular to the flow direction of the first cells may not be the same. That is, the first cell may be constituted by a plurality of types of cells having different cross-sectional shapes perpendicular to the cell flow path direction and different cross-sectional area sizes. In the first cell, the size of the cross-sectional area perpendicular to the flow path direction may be the same.

  The shape of the cross section perpendicular to the flow path direction of the first cell is not particularly limited, and for example, it is preferable to combine a triangular, quadrangular, or octagonal cell with a quadrangular cell. With this configuration, it becomes possible to dispose the opening area reducing members in a staggered manner on the end surface on the outflow side of the honeycomb structure, and the first cell and the second cell are adjacent to each other with a partition wall therebetween. Can be arranged to do.

[1-2b] Second cell:
In the second cell 14b, the opening area reducing member 18 is disposed in the opening at the end on the outflow side end surface 34 side so as to block a part of the opening, and the end on the outflow side end surface 34 side The cell 14 is formed so that the area of the cross section perpendicular to the cell flow path direction is reduced. That is, the second cell 14b has a cell 14 in which the opening area reducing member 18 is disposed in the opening at the end on the outflow side end surface 34 side of the cell formed in the same manner as the first cell 14a. It is.

  If this second cell is a cell formed so that the area of the cross section perpendicular to the flow path direction is reduced by the opening area reducing member, the area of the cross section perpendicular to the flow path direction in each second cell. May not be the same. That is, the shape of the cross section perpendicular to the flow direction of the cell is different, and a plurality of types of cells having different sizes of the cross section area (the cross section area other than the portion where the opening area reducing member is disposed), The second cell may be configured. Of course, in all the second cells, the cross-sectional area perpendicular to the flow path direction (the cross-sectional area other than the portion where the opening area reducing member is disposed) May be configured identically.

  Also, in the area of the cross section perpendicular to the flow path direction at the end on the outflow side where the opening area reducing member is disposed (that is, the area of the opening on the end surface on the outflow side), The two cells may be configured to be the same size or different sizes. In the honeycomb structure of the present embodiment, the area of the opening on the outflow side end face side of the second cell is preferably configured to have the same size.

  Also, the shape of the cross section perpendicular to the flow direction of the second cell (the cross section other than the portion where the opening area reducing member is disposed) is not particularly limited, and for example, a preferable cross section in the first cell described above. A shape similar to the shape can be cited as a preferred example. One of the preferred embodiments is that the first cell is an octagon and the second cell is a rectangle, or the first cell is a rectangle and the second cell is an octagon.

In the honeycomb structure of the present embodiment, the second cell is opened by the opening area reducing member with the area of the opening on the outflow side end face (that is, the area of the opening reduced by the opening area reducing member). proportion to the area of the opening of the front part of the section is closed (hereinafter, sometimes referred to as "the ratio of the area of the opening at the end face of the outlet-side"), that has been formed so as to be 20 to 95% . In addition, the lower limit of the ratio of the area of the opening in the end face on the outflow side is more preferably 30% or more, particularly preferably 40% or more, and the upper limit is further preferably 80% or less. 70% or less is particularly preferable. By comprising in this way, the increase in pressure loss can be suppressed effectively.

  The “area of the opening portion reduced by the opening area reducing member” refers to the area of the through hole formed in the opening area reducing member. For example, as shown in FIG. When the area of the through-hole formed in the reducing member 18 is not constant in the depth direction of the opening area reducing member 18, the area L of the portion where the area of the through-hole formed in the opening area reducing member 18 is minimized. Is the area of the opening of the portion reduced by the opening area reducing member 18. Here, FIG. 1D 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. 1D is the same cross section as the cross section shown in FIG. 1C.

  The area of the opening of the portion reduced by the opening area reducing member can be easily calculated by image analysis. However, as shown in FIG. 1D, the area of the opening (that is, the area of the through hole) is not constant. If necessary, the area L of the minimum part can be obtained by cutting the cross section at regular intervals.

  Note that when the ratio of the area of the opening on the outflow side end face described above is less than 20%, from the opening on the outflow side end face of the second cell (that is, the opening reduced by the opening area reducing member). There is a case where exhaust gas hardly flows out and only purification by the first cell can be performed. On the other hand, if it exceeds 95%, a pressure difference between the second cell and the first cell is less likely to occur, so that it is difficult for the exhaust gas to permeate from the second cell into the first cell. Thus, the effect of improving the purification efficiency may be reduced.

In addition, the second cell has a part of the opening by the opening area reducing member, which is the sum of the areas of the openings on the end surface on the outflow side (that is, the sum of the areas of the openings reduced by the opening area reducing member). proportion to the sum of the areas of the front opening is closed (hereinafter, sometimes referred to as "the ratio of the sum area of the openings at the end face on the outflow side") is, that have been formed to be 20 to 95% . The lower limit of the ratio of the total area of the openings on the outflow side end face is more preferably 30% or more, particularly preferably 40% or more, and the upper limit is further 80% or less. It is preferably 70% or less.

  When the ratio of the total area of the openings on the outflow side end face described above is less than 20%, from the opening on the outflow side end face of the second cell (that is, the opening reduced by the opening area reducing member). In some cases, the total flow rate of the exhaust gas flowing out decreases, and only purification by the first cell can be performed. On the other hand, if it exceeds 95%, a pressure difference between the second cell and the first cell is less likely to occur, so that it is difficult for the exhaust gas to permeate from the second cell into the first cell. Thus, the effect of improving the purification efficiency may be reduced.

  Note that the ratio of the area of the opening on the end face on the outflow side and the ratio of the total area of the opening on the end face on the outflow side may be uniform over the entire end face of the honeycomb structure. It may be changed. For example, reducing the ratio of the opening in the vicinity of the center of the end surface where the exhaust gas flow rate is fast, while increasing the vicinity of the outer peripheral portion of the end surface where the exhaust gas flow rate is slow and slow increases the flow velocity distribution uniformity effect. In the sense, this is a preferred embodiment.

  In the honeycomb structure of the present embodiment, for example, partition walls in a cross section perpendicular to the axial direction of the honeycomb structure portion (that is, the cell flow direction) are formed in a lattice shape, and the cross section perpendicular to the cell flow direction is formed. When the shape is a quadrangle, it is preferable that the first cells and the second cells are alternately arranged across the partition walls, that is, the first cells and the second cells are arranged in a staggered manner. By comprising in this way, the permeation | transmission of the exhaust gas from a 2nd cell to a 1st cell is performed more efficiently, and the purification | cleaning efficiency of exhaust gas can be improved favorably.

  In the honeycomb structure of the present embodiment, the number of second cells is preferably 45 to 50%, more preferably 47.5 to 50%, based on the total number of cells. . With this configuration, it is possible to effectively improve the exhaust gas purification efficiency while suppressing an increase in pressure loss.

[1-2b-1] Opening area reducing member:
The opening area reducing member is a member disposed so as to block a part of the opening in the opening on the end face on the outflow side of the second cell.

  Such an opening area reducing member is, for example, an opening area reducing member in an opening at the end of the second cell on the outflow side (hereinafter sometimes simply referred to as “outflow side opening”). The slurry for reducing the opening area containing the material constituting the material is filled, and the outflow side opening of the second cell is completely sealed, and then part of the part sealed by the slurry for reducing the opening area It can be formed by drilling a through-hole penetrating from the end surface side on the outflow side to the inside of the second cell. The method for forming the opening area reducing member is not limited to the above-described method. For example, a plug-like member having a through-hole formed in advance is disposed in the outflow side opening of the second cell. It can also be formed.

  The opening area reducing member is not particularly limited as long as the opening area of the outflow side opening of the second cell can be reduced. For example, the opening area reducing member has the same quality as the partition, and acid treatment. Those having been subjected to the above, a catalyst material and the like can be suitably used.

  The opening area reducing member is preferably made of a porous body having a porosity of 20 to 80%. By comprising in this way, even an opening area reduction member can contribute to the purification performance improvement using the surface area of a pore. 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 opening area reducing member is more preferably 40 to 75%, and particularly preferably 65 to 75%.

  Further, the opening area reducing member may be formed by acid treatment. More specifically, it may be formed by enlarging the pores by immersion in hydrochloric acid or the like in order to increase the porosity of the opening area reducing member. By comprising in this way, the target porosity can be obtained.

  Further, the opening area reducing member may be formed of a catalyst material (for example, a catalyst composition). More specifically, it may be formed by a catalyst material (for example, a catalyst composition) coated on the honeycomb structure. By comprising in this way, an opening area reduction member also shows catalyst performance and can contribute to purification performance improvement.

  The opening area reducing member preferably has a length from the end face in the outflow side opening to the end face on the second cell inner side, that is, the arrangement depth of the opening area reducing member is 0.3 to 10 mm. More preferably, it is 0.5-5 mm. For example, when the length (arrangement depth) is less than 0.3 mm, the mechanical strength of the opening area reducing member decreases, and the bonding force between the opening area reducing member and the partition cannot be sufficiently obtained. The opening area reducing member may be easily damaged by exhaust gas pressure or external vibration. On the other hand, if it exceeds 10 mm, the length of the portion where the area of the cross section perpendicular to the flow path direction is reduced becomes too long, and the effective area of the partition wall through which the exhaust gas permeates decreases. Purification efficiency may not be obtained.

  For the shape of the opening on the outflow side of the second cell formed so that the area of the cross section perpendicular to the cell flow path direction is reduced by the opening area reducing member, the opening of the second cell is There is no particular limitation as long as the shape can achieve the effects of the present invention described above by reducing the size. For example, in FIG. 1B, the opening area reducing member 18 is disposed in the outflow side opening of the second cell 14b, and the opening of the second cell 14b is formed in a circular shape by the opening area reducing member 18. Although not shown, the shape of the opening of the second cell may be a square, triangle, hexagon, ellipse, or the like. Further, it may be an indefinite shape that is not fixed in a certain shape. In addition, the shape of the opening formed by the opening area reducing member may be different for each second cell.

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

  The manufacturing method of the honeycomb structure of the present embodiment is the same as that of the honeycomb structure of the present invention described above, that is, as shown in FIGS. 1A and 1B, from the inflow end face 32 to the outflow end face 34. The first cell 14a having a constant cross-sectional area perpendicular to the flow path direction and an opening at the end on the outflow side end face 34 side so as to block a part of the opening. A plurality of second cells 14b provided with an area reduction member 18 and formed so that the area of the cross section perpendicular to the cell flow path direction is reduced at the end on the outflow side end face 34 side. This is a method of manufacturing the honeycomb structure 1 including the columnar honeycomb structure portion 2 in which the cells 14 are defined by the porous partition walls 12.

  As shown in FIG. 2A, the method for manufacturing a honeycomb structure of the present embodiment is a columnar honeycomb formed body having partition walls 52 that form a plurality of cells 54 that form a ceramic forming raw material and serve as fluid flow paths. 2 (b), and as shown in FIG. 2B, a plugging slurry 86 is filled in the opening of a predetermined cell 54b on one end face 84 side of the obtained honeycomb formed body 72, In step (2) of obtaining a plugged honeycomb formed body 74 in which the openings of the cells 54b are plugged, and as shown in FIG. 2C, the plugged portions 64 in the obtained plugged honeycomb formed body 74 are A through-hole 66 penetrating from one end face 84 side to the inside of the predetermined cell 54b plugged is drilled to reduce the area of the opening of the predetermined cell 54b on one end face 84 side. Step of obtaining body 76 (3 When, as shown in FIG. 2D, the step (4) to obtain a honeycomb structure 71 was fired an opening area reduced honeycomb formed body 76 obtained, a method for manufacturing a honeycomb structure with a.

  Here, FIG. 2A to FIG. 2D are explanatory views for explaining each step of one embodiment of the method for manufacturing a honeycomb structure of the present invention. 2A shows the step (1), FIG. 2B shows the step (2), FIG. 2C shows the step (3), and FIG. 2D shows the step (4).

  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 method for manufacturing a honeycomb structured body of the present embodiment, as shown in FIG. 2B, in the step (2), in the cell adjacent to the predetermined cell 54b (remaining cell 54a) with the partition wall 52 therebetween, It is preferable to dispose a mask 68 that covers the opening on the one end face 84 side of the adjacent cell 54a, and fill only the predetermined cell 54b with the plugging slurry 86.

  That is, the second cell 14b is formed by the above-described predetermined cell 54b (see FIG. 2C), and the remaining cell 54a (see FIG. 2B) in which the mask 68 (see FIG. 2B) is disposed in the opening portion is used. One cell 14a is formed. In addition, one end face 84 (see FIG. 2B) filled with the plugging slurry becomes the outflow side end face 34 of the honeycomb structure, and the opposite end face (the other end face 82 (see FIG. 2B)) flows in. It becomes the end face 32 on the side.

  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):
In the step (1), as shown in FIG. 2A, 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. 2B, the plugging slurry 86 is filled in the opening portion 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 having plugged openings.

  In the manufacturing method of the honeycomb structure of the present embodiment, when the opening area reducing member disposed in the outflow side opening of the second cell is formed, the outflow side opening is formed by the plugging slurry 86. Once plugged, in the subsequent step (3), a through-hole is drilled in the plugged portion to form an opening area reducing member that covers a part of the outflow side opening of the second cell.

  And in the manufacturing method of the honeycomb structure of the present embodiment, one end face 84 of the adjacent cell 54a is adjacent to the predetermined cell 54b to be plugged and the cell (remaining cell 54a) adjacent to the partition wall 52. It is preferable to dispose a mask 68 covering the opening on the side and fill the plugging slurry 86 only in the predetermined cells 54b.

  With this configuration, in the obtained honeycomb structure, at least the second cell is disposed so as to be adjacent to the first cell with the partition wall therebetween, and the honeycomb structure of the present invention can be efficiently used. Can be manufactured automatically.

  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.

  Further, when the honeycomb formed body formed in the step (1) is formed such that partition walls in a cross section perpendicular to the axial direction thereof are formed in a lattice shape, and the shape of the cross section perpendicular to the flow path direction of the cell is a square, The mask 68 is disposed so that the predetermined cells 54b and the remaining cells 54a are alternately arranged across the partition wall 52, that is, the predetermined cells 54b and the remaining cells 54a are arranged in a staggered manner. In this case, it is preferable to make a hole in the adhesive film 68a.

  Examples of the plugging slurry for forming the opening area reducing member include a slurry in which the ceramic raw material and the additive used for obtaining the above-described honeycomb formed body 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.

  Further, after forming the plugged portions 64 with the plugged slurry in this way, the obtained plugged honeycomb formed body 74 may be further dried.

[2-3] Step (3):
In step (3), as shown in FIG. 2C, the plugged portion 64 of the obtained plugged honeycomb formed body 74 penetrates to the inside of the predetermined cell 54b plugged from the one end face 84 side. This is a step of drilling the through-hole 66 to obtain an opening area reduced honeycomb formed body 76 in which the area of the opening of the predetermined cell 54b is reduced on the one end face 84 side.

  Thereby, the opening area reduction member arrange | positioned so that the plugging part 64 by which the through-hole 66 was pierced may block a part of the outflow side opening part of the predetermined cell 54b can be formed.

  Although there is no restriction | limiting in particular about the method of drilling the through-hole 66, For example, as shown to FIG. 2C, it can carry out using the jig 88 which has several acicular protrusion 88a like a sword mountain. Such a jig 88 is preferably configured such that the plurality of needle-like protrusions 88a are located at the center of the outflow side opening of a predetermined cell 54b that pierces the through hole 66. Further, the diameter of the through hole 66 can be adjusted by the size of the outer diameter of the protrusion 88a of the jig 88.

[2-4] Step (4):
Step (4) is a step of obtaining the honeycomb structure 71 by firing the obtained aperture area-reduced honeycomb formed body 76 as shown in FIG. 2D. Thus, the honeycomb structure of the present invention as shown in FIGS. 1A and 1B 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.

  The plugging portions and the through holes can be arranged after the honeycomb formed body is fired. The method for manufacturing the honeycomb structure of the present invention is not limited to the above method, and for example, the following method may be used.

  First, in accordance with a conventionally known method, a honeycomb structure having a porous partition wall, in which a plurality of cells serving as fluid flow paths are formed by the partition wall from the end surface on the inflow side to the end surface on the outflow side. Create a body. Next, after adhering an adhesive film to the entire end face (on the side where the plugging is provided) of the honeycomb structure, holes are formed in the portions corresponding to the cells where the plugging portions are to be formed with a laser. As an adhesive film, what applied the adhesive material to the one surface of the film which consists of resin, such as polyester, polyethylene, a thermosetting resin, etc. can be used conveniently.

  Then, the opening area can be reduced only for a desired cell by immersing in the slurry for reducing the opening area from the film sticking surface to a depth at which the opening area is desired to be reduced. Depending on the viscosity of the slurry for reducing the opening area and the degree to be reduced, the opening can be reduced to a desired size only by the operation of pulling up from the immersion. In addition, it is preferable to reduce an opening part to a desired magnitude | size by blowing off surplus slurry with compressed air etc. as needed. In addition, in each cell that reduces the opening area by partially injecting compressed air or the like on the end face of the honeycomb structure, or by changing the pressure of the compressed air to be injected, etc. Each can be changed.

[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 the end face on the inflow side, The partition wall is used to purify harmful substances such as carbon monoxide (CO), hydrocarbon (HC), nitrogen oxide (NO _x ), etc. with a catalyst. The permeated fluid (purified gas) that has permeated through the partition wall in this manner flows out from the opening on the end surface on the outflow side of the adjacent cell.

  In the honeycomb catalyst body of the present embodiment, the area of the opening of the cell on the inflow side end face of the second cell is reduced by the opening area reducing member. The partition walls forming the two cells can be permeated to actively flow out into the adjacent first cells, and 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 in the second 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 pressure loss increases even if the exhaust gas purification efficiency is improved as described above. Can be effectively 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 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, for example, the honeycomb structure according to the 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, 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.

  In addition, the catalyst can carry | support a catalyst, for example by performing a deaeration process so that a catalyst solution may be impregnated into the pore formed in the partition, after making a through-hole in a plugging part. An example of a method for carrying a catalyst by performing a deaeration process is a method of carrying a catalyst in a reduced-pressure atmosphere.

  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.

[Hole Opening Ratio (%)]: The area of the opening on the outflow side end face of the second cell in the honeycomb structure constituting the honeycomb structure (the area of the opening in the state reduced by the opening area reducing member) The ratio (percentage) of the total area of the second cell before the part of the opening is closed by the opening area reducing member to the total opening area of the second cell is expressed as the hole opening ratio (%) of the second cell. did.

[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, in the obtained honeycomb molded body, in the opening of the cell on one end surface side corresponding to the end surface on the outflow side, the end surface on the outflow side exhibits a checkered pattern (that is, a staggered pattern). A plugged portion was formed at the end of a predetermined cell corresponding to the second cell to obtain a plugged honeycomb formed body. In addition, the arrangement | positioning depth of the plugging part was 2 mm from the end surface of the honeycomb molded body. As the plugging slurry for forming the plugged portion, a cordierite forming raw material and a binder prepared at the same ratio as the cordierite forming raw material used for the above-mentioned honeycomb molded body kneaded material are blended, What adjusted the viscosity to 180-350 dPa * s with the thickener was used.

  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 hole is formed on the end surface side on the outflow side. An opening area reduced honeycomb formed body in which the area of the opening of the cell (second cell) was reduced was obtained. In the present example, the through hole was drilled so that the hole opening ratio (%) of the second cell was 25%.

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. Note that 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 of the examples and comparative examples. About what provided the area reduction member, the arrangement | positioning depth was 2 mm.

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 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. 3 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). 4 and 5 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. 4 shows the result of measuring hydrocarbon (HC) as a harmful component, and FIG. 5 shows the result of measuring nitrogen oxide (NO _x ) as a harmful component.

(Examples 2 to 4)
Except for changing the hole opening ratio (%) of the second cell 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 manufacture 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.

(Result 1)
As shown in Table 2 and FIG. 3, in the measurement of 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 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. 4 and FIG. 5, in the measurement of the harmful component discharge amount, it was confirmed that the purification performance of the honeycomb catalyst bodies of Examples 1 to 4 improved as the hole opening ratio decreased. It was done. Further, even in Example 4 where the hole opening ratio was 95%, it was shown that HC could be reduced by about 25% and NO _x could be reduced by about 40%.

  FIG. 6 shows the relationship between pressure loss and harmful component emissions (hydrocarbon (HC) emissions). In FIG. 6, the ratio of each Example 1-4 with respect to the pressure loss and harmful component discharge | emission amount of the comparative example 1 is shown, and a horizontal axis is a case where the pressure loss of the comparative example 1 is set to 1. It is a ratio, and a vertical axis | shaft is a ratio when the harmful component discharge | emission amount of the comparative example 1 is set to 1.

  As shown in FIG. 6, the honeycomb catalyst bodies of Examples 1 to 4 exceeded the trade-off line X in which a reduction of 15% 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 “trade-off line in which reduction of 15% 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 discharge amount is 0.85 (that is, Comparative Example 1). Is a curve connecting points that are 85% of the value of.

(Examples 5 to 7 and Comparative Examples 2 and 3)
Except for changing the average pore diameter (μm) as shown in Table 4, a honeycomb structure configured in the same manner as in Example 2 (pore opening ratio 50%) was manufactured, and the resulting honeycomb structure Then, a catalyst was supported by the same method as in Example 1 to manufacture honeycomb catalyst bodies (Examples 5 to 7 and Comparative Examples 2 and 3). With respect to each of the honeycomb catalyst bodies of Examples 5 to 7 and Comparative Examples 2 and 3, the above-described pressure loss measurement and harmful component discharge amount were measured. The results are shown in Tables 5 and 6. FIG. 7 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). 8 and 9 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. 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.

(Result 2)
As shown in Table 5 and FIG. 7, in the measurement of 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. 8, and FIG. 9, it was found that the average pore diameter has an optimum value in the measurement of the harmful component discharge amount, and the optimum value is in the vicinity of 20 μm in Example 6. That is, when the average pore diameter is smaller than 13 μm as in Comparative Example 2, the pores of the partition walls are blocked, making it impossible to use the surface area of the pores, and the harmful component discharge amount is greatly increased. Moreover, when the average pore diameter is larger than 70 μm as in Comparative Example 3, the surface area due to the pores in the partition walls is remarkably reduced, and the harmful component discharge amount is greatly increased.

  FIG. 10 shows the relationship between pressure loss and harmful component emissions (hydrocarbon (HC) emissions). In FIG. 10, the ratio of each Example 5-7 with respect to the pressure loss and harmful component discharge | emission amount of the comparative example 1 and the comparative examples 2 and 3 is shown, and a horizontal axis is 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. 10, the honeycomb catalyst bodies of Examples 5 to 7 exceed the trade-off line X in which a reduction of 15% is 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.

(Examples 8 to 10 and Comparative Examples 4 and 5)
Except for changing the porosity (%) as shown in Table 7, a honeycomb structure configured in the same manner as in Example 2 (pore opening ratio 50%) was manufactured, and the resulting honeycomb structure was obtained. A catalyst was supported by the same method as in Example 1 to manufacture honeycomb catalyst bodies (Examples 8 to 10 and Comparative Examples 4 and 5). With respect to each of the honeycomb catalyst bodies of Examples 8 to 10 and Comparative Examples 4 and 5, the above-described pressure loss measurement and harmful component discharge amount were measured. The results are shown in Table 8 and Table 9. 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). FIG. 12 and FIG. 13 are graphs showing the measurement results of the harmful component discharge amount, the horizontal axis indicates the platinum group metal loading (g / L), and the vertical axis indicates the harmful component discharge 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 3)
As shown in Table 8 and FIG. 11, 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. 12, and FIG. 13, in the measurement of the harmful component emission amount, it was found that there is an optimum value for the porosity, 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 4, the pore surface area of the partition walls is decreased, and the harmful component discharge amount is greatly increased. In addition, when the porosity is larger than 80% as in Comparative Example 5, the harmful component discharge amount is the lowest, but the strength is lowered, so that it is not suitable for actual vehicle application.

  FIG. 14 shows the relationship between pressure loss and harmful component emissions (hydrocarbon (HC) emissions). FIG. 14 shows the ratios of Examples 8 to 10 and Comparative Examples 4 and 5 with respect 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. 14, the honeycomb catalyst bodies of Examples 8 to 10 exceed the trade-off line X in which a reduction of 15% is 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.

  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 uses the noble metal used for the catalyst by improving the purification efficiency. The possibility of reducing the amount by at least 30% 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 sectional drawing which shows typically other embodiment of the honeycomb structure of this invention. It is explanatory drawing explaining the process (1) of one Embodiment of the manufacturing method of the honeycomb structure of this invention. It is explanatory drawing explaining the process (2) of one Embodiment of the manufacturing method of the honeycomb structure of this invention. It is explanatory drawing explaining the process (3) of one Embodiment of the manufacturing method of the honeycomb structure of this invention. It is explanatory drawing explaining the process (4) of one Embodiment of the manufacturing method of the honeycomb structure of this 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. 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: honeycomb structure, 2: honeycomb structure part, 12: partition wall, 14: cell, 14a: first cell, 14b: second cell, 16: outer peripheral wall, 18: opening area reducing member, 22: opening part Sealing member, 32: end face on the inflow side, 34: end face on the outflow side, 52: partition wall, 54: cell, 54a: cell (remaining cell), 54b: cell (predetermined cell), 64: plugging portion , 66: through hole, 68: mask. 68a: Adhesive film, 71: Honeycomb structure, 72: Honeycomb formed body, 74: Plugged honeycomb formed body, 76: Opened area reduced honeycomb formed body, 82: The other end face, 84: One end face, 86: Eye Sealing slurry, 88: jig, 88a: protrusion. L: The area of the part where the area of the through hole formed in the opening area reducing member is minimized.

Claims (10)

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 a first cell having a cross-sectional area perpendicular to the cell flow path direction from the inflow side end surface to the outflow side end surface, and the outflow side end surface. An opening area reducing member is disposed in the opening at the end on the side so as to block a part of the opening, and has a cross-section perpendicular to the flow direction of the cell at the end on the outflow side. A second cell formed so as to reduce the area , and a honeycomb structure comprising :
At least the second cell is disposed so as to be adjacent to the first cell with a partition wall therebetween, and the second cell is the total opening area of the opening on the outflow side end surface. The ratio of the area of the opening before the opening is partially closed by the reducing member is 20 to 95%, and the second cell has an end face on the outflow side. The honeycomb structure is formed such that the ratio of the area of the opening to the area of the opening before the opening is reduced by the opening area reducing member is 20 to 95% . In the second cell, the area of the cross section perpendicular to the flow direction of the cell in the portion where the opening area reducing member is not disposed is the same as the area of the cross section perpendicular to the flow direction of the first cell. The honeycomb structure according to claim 1, wherein the honeycomb structure is formed as described above. The honeycomb structure according to claim 1 or 2 , wherein the opening area reducing member is made of a porous body having a porosity of 20 to 80%. The honeycomb structure according to any one of claims 1 to 3 , wherein a number of the second cells is 45 to 50% with respect to a total number of the plurality of cells. The honeycomb structure according to any one of claims 1 to 4 , wherein the opening area reducing member is formed by acid treatment. The honeycomb structure according to any one of claims 1 to 4 , wherein the opening area reducing member is formed of a catalyst material. A honeycomb structure according to any one of claims 1 to 6 , 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 surface of the partition walls. Honeycomb catalyst body. The honeycomb catalyst body according to claim 7 , wherein 100 to 250 g of the catalyst is supported per 1 L of the volume of the honeycomb structure. A step (1) of obtaining a columnar honeycomb formed body having partition walls that form a plurality of cells that serve as fluid flow paths by forming a ceramic forming raw material;
A step of filling a plugging slurry into a predetermined cell opening on one end face side of the obtained honeycomb molded body to obtain a plugged honeycomb molded body plugged with the predetermined cell opening (2) and
A through-hole penetrating from the one end surface side to the inside of the plugged cell is drilled in the plugged portion of the obtained plugged honeycomb formed body, and the predetermined cell is formed on the one end surface side. A step (3) of obtaining an opening area-reduced honeycomb formed body in which the area of the opening is reduced;
And firing the obtained opening area-reduced honeycomb formed body to obtain a honeycomb structure (4) ,
The plurality of cells of the obtained honeycomb structure includes a first cell in which an area of a cross section perpendicular to a flow direction of the cell is formed in a constant size from an end surface on the inflow side to an end surface on the outflow side, An opening area reducing member is disposed in the opening at the end on the outflow side so as to block a part of the opening, and at the end on the outflow side in the flow direction of the cell. A second cell formed so that the area of the vertical cross section is reduced, and a honeycomb structure comprising:
At least the second cell is disposed so as to be adjacent to the first cell with a partition wall therebetween, and the second cell is the total opening area of the opening on the outflow side end surface. The ratio of the area of the opening before the opening is partially closed by the reducing member is 20 to 95%, and the second cell has an end face on the outflow side. In the honeycomb structure, the ratio of the area of the opening to the area of the opening before the opening is reduced by the opening area reducing member is 20 to 95% . Production method. In the step (2), a mask that covers the opening on the one end face side of the adjacent cell is disposed on the adjacent cell across the partition wall from the predetermined cell to be plugged. The method for manufacturing a honeycomb structured body according to claim 9 , wherein only the cells are filled with the plugging slurry.

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