JP5495888B2 - Honeycomb structure, filter using the same, and exhaust gas treatment apparatus - Google Patents

Description

  The present invention relates to an internal combustion engine, an incinerator, which is a power source for automobiles, forklifts, generators, ships, hydraulic excavators, bulldozers, wheel loaders, rough terrain cranes, tractors, combines, tillers, railway vehicles, construction vehicles, etc. Honeycomb structure used in filters for collecting particulates mainly composed of carbon contained in exhaust gas generated from boilers, etc., filters for decomposing and removing harmful dioxins, filters using the same, and exhaust gas The present invention relates to a processing apparatus.

  Conventionally, fine particles mainly composed of carbon (particularly fine particles mainly composed of carbon in exhaust gas from diesel engines) and sulfur contained in exhaust gas generated from internal combustion engines, incinerators, boilers, etc. are oxidized. Since fine particles mainly composed of sulfate and fine particles such as unburned hydrocarbons made of polymers cause environmental pollution, for example, these fine particles are collected with a filter using a honeycomb structure. And removed.

  FIG. 11 shows a honeycomb structure used in a conventional filter, in which (a) is a side view and (b) is a partially broken front view.

  A honeycomb structure 31 shown in FIG. 11 includes a partition wall 33 having a wall surface along the axial direction X, a plurality of flow holes 32 partitioned by the partition wall 33, and a seal that alternately seals both ends of the plurality of flow holes 32. A honeycomb structure provided with a stop material.

  The exhaust gas flowing in from the end surface (IF) on the inflow side of the honeycomb structure 31 is introduced into the flow holes 32, then enters the adjacent flow holes 32 through the partition walls 33, and from the end surface (OF) on the outflow side. leak. When the exhaust gas passes through the partition wall 33, various fine particles contained in the exhaust gas are collected in the partition wall 33.

  When the honeycomb structure 31 continues to collect such fine particles, the air permeability of the partition wall 33 is gradually impaired due to the accumulation of the collected fine particles. Therefore, the honeycomb structure 31 must be regenerated by periodically removing the fine particles. Don't be.

The honeycomb structure 31 can be regenerated by heating to 600 ° C. or more to burn and remove fine particles. An oxidation catalyst is disposed on the exhaust gas inflow side of the honeycomb structure 21, and light oil or the like is disposed on the oxidation catalyst. For example, there is a method of burning and removing fine particles using heat generated by an oxidation reaction caused by supplying the fuel.

  However, when the honeycomb structure 31 is regenerated by these methods, the greater the amount of collected fine particles, the more time it takes to remove the fine particles. During this time, the temperature of the honeycomb structure 31 rises and rises. In some cases, the honeycomb structure 31 may be cracked or melted due to thermal stress.

  In order to prevent such cracks and melting damage, a honeycomb structure as shown in Patent Document 1 has been proposed.

That is, Patent Document 1 discloses an inflow side cell clogged on the exhaust gas downstream side, an outflow side cell adjacent to the inflow side cell and clogged on the exhaust gas upstream side, the inflow side cell and the outflow side cell. There has been proposed a honeycomb structure including a porous cell partition wall that is partitioned and has a large number of pores, and has a longer cell length in the center than in the outer periphery. Such conventional honeycomb structures are shown in FIGS.

  12 and 13 are cross-sectional views showing examples of conventional honeycomb structures.

  The honeycomb structure 31 shown in FIG. 12 is smoothly continuous in a cross-sectional arc shape protruding outward toward the outer peripheral surface of the center portion X that is exposed.

  Further, the honeycomb structure 31 shown in FIG. 14 is smoothly continuous in a circular arc shape that is convex inward toward the outer peripheral surface of the center portion Y that is exposed. And according to this, since the cell length of the central part is longer than the cell length of the outer peripheral part, the temperature difference between the central part and the outer peripheral part can be reduced, and the generation of cracks due to thermal stress during forced regeneration It can be suppressed.

JP 2007-138747

However, in the conventional honeycomb structure 31 shown in FIGS. 12 and 13 proposed in Patent Document 1, the center part melts down at the time of forced regeneration, or a crack occurs at the boundary part between the center part and the outer peripheral part at the downstream end part. Can be suppressed to some extent, but the center of the downstream end (
In FIGS. 12 and 13, the positions of the inner end portions of the sealing material 34 are aligned in a straight line, so that the melting damage and cracks at these positions cannot be suppressed. Similarly, at the upstream end portion, the position of the inner end portion of the sealing material 34 is aligned linearly at both the center portion and the outer peripheral portion, so that melting damage and cracks at this position cannot be suppressed.

  In view of such a problem, the present invention provides a honeycomb structure, a filter, and an exhaust gas processing apparatus capable of suppressing melting damage and cracks occurring at the upstream end portion and the downstream end portion during forced regeneration over a long period of time. Is to provide.

The honeycomb structure of the present invention includes a plurality of flow holes partitioned by partition walls having wall surfaces along the axial direction, and a sealing material that alternately seals one end and the other end of the plurality of flow holes. The honeycomb structure is provided, the end faces on both sides of the honeycomb structure are curved in a convex shape, and in the sealing material disposed around one of the flow holes, the adjacent sealing members intersecting the position of the inner surface and the wall surface of the wood has Tsu Do different, inner surface shape of the encapsulant, conical, hemispherical and has a they either convex complexed, adjacent The inner surface shape of the sealing material is different .

  In addition, the honeycomb structure of the present invention is characterized in that, in any of the above-described configurations, an angle formed between the inner surface of the sealing material and the wall surface is 5 degrees or more and less than 55 degrees.

The honeycomb structure of the present invention is characterized in that, in any one of the above structures, the partition wall is formed of a sintered body mainly composed of aluminum titanate.

  Moreover, the honeycomb structure of the present invention is characterized in that, in any one of the above structures, the sealing material is a sintered body mainly composed of aluminum titanate.

  Moreover, the filter of this invention WHEREIN: One end which is not sealed of the said circulation hole is set as an inlet_port | entrance, and the other end which is not sealed of the other circulation hole via the said partition in said structure The exhaust gas is allowed to pass through at the outlet, and the particulates in the exhaust gas are collected by the partition walls.

  Further, the exhaust gas treatment device is characterized by including the filter having the above-described configuration.

According to the honeycomb structure of the present invention, a plurality of flow holes partitioned by partition walls having wall surfaces along the axial direction, and a sealing material that alternately seals one end and the other end of the plurality of flow holes, The end faces on both sides of the honeycomb structure are curved in a convex shape, and the inside of the adjacent sealing material in the sealing material arranged around one flow hole by intersecting position between the surface and the wall surface of the are Tsu Do different, stress generated at the positions intersecting with the inner surface and the wall surface of the sealing material heat during forced regeneration neighboring be given iteration adjacent Since the position where the inner surface of the sealing material intersects with the wall surface is more relaxed, cracks and melting damage occurring at this position are suppressed. In addition, even if heat is repeatedly applied, the end faces on both sides of the honeycomb structure are curved in a convex shape, so the stress generated on the end faces is more relaxed than in the case where the end faces are flat. that cracks and melting is suppressed. In addition, since the inner surface shape of the sealing material is one of a conical shape, a hemispherical shape, and a convex shape in which these are combined, even if heat during forced regeneration is repeatedly applied, Since the stress generated on the surface is more easily dispersed than when the inner surface is in the shape of a pyramid or a polyhedron, cracks and melting damage generated on the inner surface of the sealing material are suppressed. Furthermore, because the inner surface shape of the adjacent sealing material is different, the stress generated on the inner surface of the sealing material even when heat during forced regeneration is repeatedly applied is Since it is easier to disperse than the case where the inner surface shape is the same shape, cracks and erosion caused on the inner surface of the sealing material are suppressed.

  Further, according to the honeycomb structure of the present invention, when the angle formed between the inner surface of the sealing material and the wall surface is 5 degrees or more and less than 55 degrees, compared with the case where the angle is smaller than the range of this angle, the flow hole The volume of the particles can be increased slightly, but the amount of collected fine particles can be increased. On the other hand, compared to the case where the angle is larger than this range, the stress generated at the position where the inner surface of the sealing material intersects with the wall surface is easily dispersed, so that cracks and erosion caused at this position are further suppressed. The

  Further, according to the honeycomb structure of the present invention, when the partition wall is made of a sintered body mainly composed of aluminum titanate, such a sintered body has high thermal shock resistance, and thus deposited on the partition wall. In order to forcibly regenerate the fine particles, the partition walls are not damaged over a long period of time even if they are heated with a burner or a heater to give a sudden temperature change.

Further, according to the honeycomb structure of the present invention, when the sealing material is made of a sintered body mainly composed of aluminum titanate, such a sintered body has high thermal shock resistance. In order to burn and regenerate the fine particles deposited on the material, the encapsulant does not break for a long period of time even if it is heated with a burner or a heater to give a sudden temperature change.

  Further, according to the filter of the present invention, the catalyst is supported on the wall surface of the partition wall of the honeycomb structure of the present invention, and one end where the flow hole is not sealed is an inlet, and the flow hole and the partition wall are interposed. In the case of a filter that allows exhaust gas to pass through the other end that is not sealed in the other flow hole as an outlet and collects particulates in the exhaust gas by a partition, heat during forced regeneration is repeatedly applied. However, since the honeycomb structure that is less prone to cracking and melting is used, fine particles can be efficiently collected and removed over a long period of time.

  According to the exhaust gas treatment device of the present invention, when the filter of the present invention is provided, fine particles can be efficiently collected and removed over a long period of time, so that it is efficient over a long period of time. Can be used.

An example of an embodiment of a honeycomb structure of the present invention is shown, (a) is a perspective view, and (b) is a cross-sectional view taken along line B-B 'in (a). 1A is a cross-sectional view taken along the line CC ′ in FIG. 1A, and FIG. 1B is a DD ′ line in FIG. FIG. It is a fragmentary sectional view which shows an example of embodiment of the sealing material in the inflow side of the honeycomb structure of this invention, (a)-(d) is the convex from which the surface shape inside a sealing material differs from shape, respectively. It is a fragmentary sectional view which shows a state. It is a fragmentary sectional view which shows an example of embodiment of the sealing material in the outflow side of the honeycomb structure of this invention, (a)-(d) is the convex in which the surface shape inside a sealing material each differs in shape It is a fragmentary sectional view which shows a state. 1 is a partial cross-sectional view showing an example of an embodiment of a sealing material on the inflow side of a honeycomb structure of the present invention, and (a) to (d) show that the inner shape of the sealing material is conical or hemispherical. It is a fragmentary sectional view which shows the state of the shape which these combined. FIG. 6 is a partial cross-sectional view showing another example of the embodiment of the sealing material on the outflow side of the honeycomb structure of the present invention, in which (a) to (d) each have an inner surface shape of the sealing material. It is a fragmentary sectional view showing a different convex state. It is a schematic diagram for demonstrating the method to measure the angle which the inner surface of a sealing material and the wall surface of a partition make, (a)-(d) is a measurement in the state from which the shape of a sealing material differs, respectively. It is a schematic diagram which shows the place to do. The other example of embodiment of the honeycomb structure of this invention is shown, (a) is a side view which shows a part of inflow side, (b) is a side view which shows a part of outflow side. The other example of embodiment of the honeycomb structure of this invention is shown, (a) is a side view which shows a part of inflow side, (b) is a side view which shows a part of outflow side. 1 is a schematic cross-sectional view showing an example of an embodiment of a filter using a honeycomb structure of the present invention and an exhaust gas treatment apparatus including the filter. The honeycomb structure used for the conventional filter is shown, (a) is a side view, (b) is a partially broken front view. It is sectional drawing which shows an example of the conventional honeycomb structure. It is sectional drawing which shows an example of the conventional honeycomb structure.

  Hereinafter, an example of an embodiment of a honeycomb structure of the present invention, a filter using the honeycomb structure, and an exhaust gas treatment device will be described.

FIG. 1 shows an example of an embodiment of a honeycomb structure of the present invention, (a) is a perspective view, and (b) is a cross-sectional view taken along line BB ′ in (a). 2 shows the honeycomb structure of FIG. 1, (a) is a cross-sectional view taken along the line CC ′ in FIG. 1 (a), and (b) is DD in FIG. 1 (a). It is sectional drawing in a line.

  The honeycomb structure 1 of the example shown in FIG. 1 includes a plurality of flow holes 2 partitioned by a gas-permeable partition wall 4 having a wall surface 4a along the axial direction A, and one end and the other end of each of the plurality of flow holes 2. And sealing materials 3 and 30 for alternately sealing the two.

  When a diesel engine (not shown) is arranged on the inflow side of the honeycomb structure 1 and the diesel engine (not shown) is operated to generate exhaust gas (EG), the exhaust gas (EG) is converted into FIG. ), The honeycomb structure 1 is introduced from the flow hole 2 not provided with the sealing material 3 on the inflow side, but the outflow is blocked by the sealing material 30 provided on the outflow side. Exhaust gas (EG) whose outflow is blocked passes through the porous partition wall 4 and is introduced into the adjacent circulation hole 2 where the sealing material 30 is not provided on the outflow side. When the exhaust gas (EG) passes through the partition walls 4, fine particles mainly composed of carbon in the exhaust gas (EG) in the pores of the partition walls 4, fine particles mainly composed of sulfate formed by oxidation of sulfur, and high Particulate substances such as hydrocarbons that are not completely burned out of molecules (hereinafter collectively referred to as fine particles) are collected. The exhaust gas (EG) in which the fine particles are collected is discharged to the outside through the circulation hole 2 not provided with the sealing material 30 in a purified state.

The honeycomb structure 1 of the example shown in FIG. 1 has, for example, a cylindrical shape having an outer diameter of 100 to 200 mm and a length of 100 to 250 mm in the axial direction A, and a flow hole in a cross section perpendicular to the axial direction A 2, 1 50-800 or each cross-sectional area of the number and 1 per per square inch, 1 to 10 mm ²
And the partition 4 is 0.05-1.0 mm in thickness.

As shown in FIG. 2, the honeycomb structure 1 of the present invention has end faces 1a and 1b on both sides of the honeycomb structure 1 that are convexly curved and sealed at one end of one flow hole 2. In the stopper 3, it is important that the positions P ₁ and P ₂ where the inner surface 3 a and the wall surface 4 a intersect each other are different.

Since the positions P ₁ and P ₂ where the inner surface 3a of the adjacent sealing material 3 and the wall surface 4a intersect are different, the inner surface 3a of the adjacent sealing material 3 even when heat is repeatedly applied during forced regeneration The stress generated at the positions P ₁ and P ₂ where the wall surface 4a intersects is alleviated as compared with the case where the inner surface 3a of the adjacent sealing material 3 and the wall surface 4a intersect each other. Cracks and melting damage that have occurred are suppressed.

This also applies to the sealing material 30 formed on the outflow side in the flow hole 2, and the positions P ₃ and P ₄ where the inner surface 30 a and the wall surface 4 a intersect each other are different. Is important, and for the same reason as that on the inflow side described above, cracks and erosion that have occurred at this position are suppressed.

  Further, even if heat is repeatedly applied during forced regeneration, since the end surfaces 1a and 1b on both sides are curved in a convex shape, the stress generated on the end surfaces 1a and 1b is more relaxed than when the end surfaces 1a and 1b are flat. Cracks and melting damage that have occurred in the end faces 1a and 1b are suppressed.

  The end faces 1a and 1b on both sides preferably have a radius of curvature that is not less than 2.7 times and not more than 4.2 times the diameter of the honeycomb structure 1.

  FIG. 3 is a partial cross-sectional view showing an example of an embodiment of the sealing material on the inflow side of the honeycomb structure of the present invention, and (a) to (d) show the inner surface shape of the sealing material, respectively. It is a fragmentary sectional view which shows the convex state from which a shape differs.

  FIG. 4 is a partial cross-sectional view showing an example of an embodiment of the sealing material on the outflow side of the honeycomb structure of the present invention, wherein (a) to (d) are the surface shapes inside the sealing material. FIG. 4 is a partial cross-sectional view showing a convex state with different shapes.

  As shown in FIGS. 3A to 3D, the inner surfaces 3a of the adjacent sealing materials 3 are preferably convex shapes having different shapes. Even if heat at the time of forced regeneration is repeatedly applied, the stress generated on the inner surface 3a of the sealing material 3 is distributed more than when the shape of the inner surface 3a of the adjacent sealing material 3a is the same convex shape. Since it is easy, the crack and the melting loss which have arisen in the inner surface 3a of the sealing material 3 are suppressed.

  This also applies to the sealing material 30 formed on the outflow side, as shown in FIGS. 4A to 4D, and the inner surfaces 30a of the adjacent sealing materials 30 have different shapes. A convex shape is preferable, and cracks and erosion caused on the inner surface 30a of the sealing material 30 are suppressed for the same reason as described above.

  FIG. 5 is a partial cross-sectional view showing an example of an embodiment of the sealing material on the inflow side of the honeycomb structure of the present invention, in which (a) to (d) show that the inner shape of the sealing material is a cone. It is a fragmentary sectional view which shows the state of a shape, hemisphere, and the shape which these combined.

  FIG. 6 is a partial cross-sectional view showing another example of the embodiment of the sealing material on the outflow side of the honeycomb structure of the present invention, wherein (a) to (d) are inside the sealing material. It is a fragmentary sectional view which shows the convex state from which a surface shape differs in each shape.

As shown in FIGS. 5A to 5D, the inner surface 3a of the adjacent sealing materials 3 is preferably any one of a conical shape, a hemispherical shape, and a shape in which these are combined. is there. An inner surface 3a ₁ of the upper sealing material 3 shown in FIG. 5C has, for example, a conical and hemispherical shape. If the inner surface 3a of the adjacent sealing material 3 has a conical shape, a hemispherical shape, or a composite shape thereof, the stress generated on the inner surface 3a of the sealing material 3 even when heat is repeatedly applied. Since the inner surface 3a is more easily dispersed than when the inner surface 3a is in the shape of a pyramid or a polyhedron, cracks and erosion caused on the inner surface 3a of the sealing material 3 are further suppressed.

  This also applies to the sealing material 30 formed on the outflow side, as shown in FIGS. 6A to 6D, and the inner surface 30a of the adjacent sealing material 30 has a conical, hemispherical shape. It is preferable that any one of the shape and the shape in which these are combined is used, and for the same reason as described above, cracks and erosion caused on the inner surface 30a of the sealing material 30 are suppressed. .

  In particular, in the honeycomb structure of the present invention, it is preferable that the angle formed by the inner surface 3a of the sealing material 3 and the wall surface 4a is 5 degrees or more and less than 55 degrees. If the angle formed between the inner surface 3a and the wall surface 4a of the sealing material 3 is within this range, the volume of the flow hole 2 can be slightly increased compared with the case where the angle is smaller than this range. Almost no decrease. On the other hand, compared to the case where the angle is larger than the above range, the stress generated at the position where the inner surface 3a and the wall surface 4a of the sealing material 3 intersect is easily dispersed, so cracks and erosion occurred at this position. Is further suppressed.

  For the same reason as described above, the angle formed by the inner surface 30a of the sealing material 30 and the wall surface 4a is preferably 5 degrees or more and less than 55 degrees.

FIG. 7 is a schematic diagram for explaining a method of measuring an angle formed by the inner surface 3a of the sealing material 3 and the wall surface 4a of the partition wall 4, wherein (a) to (d) are diagrams of the sealing material. It is a schematic diagram which shows the place to measure in the state from which each shape differs.

As shown in FIGS. 7A to 7D, the angle between the inner surface 3a of the sealing material 3 and the wall surface 4a of the partition wall 4 is θ, and the height in the axial direction A from the starting point to the apex of the surface 3a. Where h is the vertical distance from the wall surface 4a to the top of the surface 3a, and the angle θ is obtained using the following equation (1), and h and d are 50-200 magnifications using a measuring microscope. It is sufficient to measure as double and use the measured value.
θ = tan ⁻¹ (h / d) (1)
In addition, the partition walls 4 constituting the honeycomb structure of the present invention have a component having a low thermal expansion coefficient, such as cordierite (2MgO.2Al ₂ O ₃ · 5SiO ₂ ), β-eucryptite (Li ₂ O · Al _2). O ₃ · 2SiO ₂ ), β-spodumene (Li ₂ O · Al ₂ O ₃ · 4SiO ₂ ), silicon carbide (SiC), silicon nitride (Si ₃ N ₄ ), sialon (Si _6-Z Al _Z O _Z N _8-Z , where z is from 0.1 to 1 in terms of solid solution), mullite (3Al ₂ O ₃ .2SiO ₂ ), potassium zirconium phosphate (KZr ₂ (PO ₄ ) ₃ ) or aluminum titanate ( al 2 Although _{TiO 5)} it is preferable that a sintered body composed mainly of, in particular, in the honeycomb structure of the present invention, the partition wall 4 is composed mainly of aluminum titanate sintered body It is preferable Ranaru. Since such a sintered body mainly composed of aluminum titanate has high thermal shock resistance, it is heated with a burner, a heater, or the like in order to burn and regenerate the fine particles collected in the partition walls 4, and the temperature changes rapidly. However, the partition wall 4 is not damaged over a long period of time.

Similarly, the sealing materials 3 and 30 constituting the honeycomb structure of the present invention are components having a low coefficient of thermal expansion, such as cordierite (2MgO · 2Al ₂ O ₃ · 5SiO ₂ ) β-eucryptite, (Li _{2 O · Al 2 O 3 ·} 2SiO 2) β- spodumene _{(Li 2 O · Al 2 O} 3 · 4SiO 2), silicon carbide (SiC), silicon nitride _{(Si 3 N} 4), sialon _{(Si 6-Z} Al _Z O _Z N _8-Z , where z is 0.1 to 1 in terms of solid solution.) Mullite (3Al ₂
It is preferable that the sintered body is mainly composed of O ₃ · 2SiO ₂ ), potassium zirconium phosphate (KZr ₂ (PO ₄ ) ₃ ) or aluminum titanate (Al ₂ TiO ₅ ). In the honeycomb structure, the sealing material 3 is preferably made of a sintered body mainly composed of aluminum titanate. Since such a sintered body mainly composed of aluminum titanate has high thermal shock resistance, in order to burn and regenerate the fine particles deposited on the sealing material 3, it is heated with a burner, a heater, etc. Even if a change is given, the sealing materials 3 and 30 are not damaged over a long period of time.

In addition, the main component in this invention means the component which occupies 50 mass% or more with respect to 100 mass% of all the components of the sintered compact which comprises the partition 4 and the sealing material 3, respectively. The content of each component constituting the partition wall 4 and the sealing material 3 can be determined by fluorescent X-ray analysis or ICP (Inductively Coupled Plasma) emission analysis. Specifically, in the case where the main component is aluminum titanate, for titanium oxide and aluminum oxide, the content of each element Ti and Al is measured and the total content converted to oxide is the total content of aluminum titanate. What is necessary is just to set it as content.

  8 and 9 show another example of the embodiment of the honeycomb structure of the present invention, (a) is a side view showing a part on the inflow side, and (b) shows a part on the outflow side. It is a side view.

  The honeycomb structure 1 of the example shown in FIG. 8 has a quadrangular shape and an octagonal shape, as shown in FIG. The flow hole 2a has a larger end surface area than the flow hole 2b.

In addition, the honeycomb structure 1 of the example shown in FIG. 9 has a quadrangular shape, as shown in FIG. 9A, the flow holes 2 a that are not sealed on the inflow side and the flow holes 2 b that are sealed are square. The area of the end face of the hole 2a is made larger than that of the flow hole 2b, and the corners thereof are arcuate. On the other hand, on the outflow side, in the honeycomb structure 1 of the example shown in FIGS. 8 and 9, as shown in (b), the flow holes 2a not sealed on the inflow side are sealed, and the flow is sealed on the inflow side. The hole 2b is configured not to be sealed.

  The configuration shown in FIGS. 8 and 9 can increase the surface area of the wall surface 4d of the partition wall 4 that collects the fine particles as compared with the case where the end faces of the flow holes 2 have the same area. The amount of collection can be increased. Further, by increasing the area of the end face of the flow hole 2a that is not sealed on the inflow side, exhaust gas (EG) is efficiently introduced into the flow hole 2a, so that particulates can be easily collected. .

  In particular, the honeycomb structure 1 of the example shown in FIG. 9 is more preferable because the corners of the flow holes 2a having a large end surface area are arc-shaped, and thus cracks that are likely to occur in the corners can be reduced. is there.

  In particular, in the honeycomb structure 1 of the example shown in FIG. 9, the diameter of the flow hole 2a that is not sealed on the inflow side is 1.55 times or more and 1.95 times or less than the diameter of the flow hole 2b that is sealed. Is preferred. By setting the ratio of diameters within this range, the amount of collected fine particles can be increased, and cracks from the radial direction do not easily enter the partition walls, so that a honeycomb structure with higher strength can be obtained. Here, the diameter of the flow hole 2 means a diameter of an inscribed circle in contact with the wall surface 4a in a cross section perpendicular to the axial direction (A), and can be measured using a measuring microscope.

  FIG. 10 is a schematic cross-sectional view showing an example of an embodiment of a filter using the honeycomb structure of the present invention and an exhaust gas treatment apparatus including the filter.

  The filter of the example of the present invention shown in FIG. 10 is a filter 5 in which a catalyst (not shown) is supported on the wall surface 4a of the partition wall 4 of the honeycomb structure 1 of the present invention. Is used as an inlet and exhaust gas (EG) is allowed to pass through with the other unsealed end of the other circulation hole 2 through the circulation hole 2 and the partition wall 4 as an outlet, and particulates in the exhaust gas are captured by the partition wall 4. To collect.

The catalyst carried on the wall surface 4a of the partition wall 4 is for oxidizing and burning fine particles in the exhaust gas collected by the partition wall 4 by supplying gas vaporized by fuel such as light oil, For example, platinum group metals such as ruthenium (Ru), rhodium (Rh), palladium (Pd), osmium (Os), iridium (Ir), and platinum (Pt) all have high oxidation activity. At least one selected from metals is preferable, and platinum (Pt) is more preferable because platinum (Pt) has the highest oxidation activity among these platinum group metals. Furthermore, in order to adsorb nitrogen oxide (NO _x ), at least one selected from alkali metal, alkaline earth metal, and rare earth metal may be supported on the wall surface 4a.

Further, the exhaust gas treatment apparatus of the present invention of the example shown in FIG. 10 is an exhaust gas treatment apparatus 20 including the filter 5 of the present invention, and the filter 5 is covered with the heat insulating material layer 6 on the outer peripheral surface. And accommodated in the case 7. The case 7 is made of, for example, stainless steel such as SUS303, SUS304, and SUS316, and has a central portion formed in a cylindrical shape and both end portions formed in a truncated cone shape, and an exhaust gas (EG) inflow side and an outflow side on the inlet 8 respectively. And exit 9. An exhaust pipe 10 is connected to the inlet 8 of the case 7, and exhaust gas (EG) is configured to flow into the case 7 from the exhaust pipe 10.

  Further, the heat insulating material layer 6 is formed in a mat shape, and is preferably made of at least one of ceramic fiber, glass fiber, carbon fiber, and ceramic whisker, and these materials are all excellent in heat insulating properties. Because.

  When a diesel engine (not shown) is activated and exhaust gas (EG) flows into the case 7 from the exhaust pipe 10, the flow holes not sealed with the sealing material 3 from the end face 1a (IF) of the honeycomb structure 1 Exhaust gas (EG) is introduced into 2. Since the flow hole 2 into which the exhaust gas (EG) is introduced is sealed with the sealing material 30 at the end on the end face 1b (OF) side, the outflow of the exhaust gas (EG) is blocked. (EG) passes through the porous partition wall 4 and is discharged from the adjacent circulation hole 2 whose end face 1b (OF) side is not sealed with the sealing material 30. In the partition wall 4, fine particles in the exhaust gas (EG) are collected in the pores therein. That is, the purified air flows into the circulation hole 2 adjacent to the circulation hole 2 into which the exhaust gas (EG) is introduced. And since the edge part by the side of the end surface 1a (IF) of the adjacent circulation hole 2 is sealed with the sealing material 3, exhaust gas (EG) does not mix in the purified air. In this manner, the exhaust gas (EG) introduced into the honeycomb structure 1 of the exhaust gas treatment device 20 is purified to a state that does not contain fine particles, and is discharged to the outside from the end face 1b (OF).

  Thus, since the exhaust gas treatment device 20 of the present invention includes the filter of the present invention, it can efficiently collect fine particles over a long period of time.

Note that the exhaust gas treatment device 20 of the example of the present invention shown in FIG. 10 has an axial length (L ₁ ) in the region where the heat insulating material layer 6 is not covered on the exhaust gas (EG) inflow side. It is preferable that it is 1/15 or less (excluding ₀ ) of the total length (L ₀ ) in the axial direction A of 5.

  When the exhaust gas treatment device 20 is used or regenerated, the vicinity of the region where the heat insulating material layer 6 is not covered on the inflow side of the exhaust gas (EG) and the region where the heat insulating material layer 6 is covered The difference in temperature is less than 1/15 of the total length of the filter 5 in the axial direction A, and the stress is easily dispersed due to this temperature difference. Cracks entering the end face on the inflow side of the honeycomb structure can be reduced.

  Next, an example of the honeycomb structure 1 shown in FIG. 1 will be described as a manufacturing method for obtaining the honeycomb structure 1 of the present invention.

First, in order to obtain the honeycomb structure 1 whose main component is aluminum titanate, 100 parts by mass of a component having a molar ratio of TiO ₂ to Al ₂ O ₃ of 40 to 60:60 to 40, and composition The expression is (
Na _y K _1-y ) AlSi ₃ O ₈ (0 ≦ y ≦ 1) represented by alkali feldspar, Mg-containing spinel-type oxide, MgO, and Mg-containing compound that is converted to MgO by firing 1 to 10 parts by mass of a single component is prepared to obtain a blended raw material. After adding a predetermined amount of pore-forming agent such as graphite, starch or resin powder to this blended raw material, add a plasticizer, thickener, lubricant, water, etc., and add a universal stirrer, rotary mill or V-type stirrer. A kneaded material is made into a slurry by using it. And this kneaded material is knead | mixed using a 3 roll mill, a kneader, etc., and a clay is obtained.

  Next, the clay is put into an extrusion molding machine equipped with a molding die whose inner diameter that determines the outer diameter of the molded body having slits for forming the partition walls 4 of the honeycomb structure 1 is, for example, 100 to 250 mm. Then, pressure is applied to form into a honeycomb shape, dried, and then cut to a predetermined length.

And after baking a molded object at 1250 to 1700 degreeC in air | atmosphere atmosphere using baking furnaces, such as an electric furnace or a gas furnace, the end surface 1b (OF) is masked in a checkered pattern, and the end surface 1b side of a sintered compact is made into the side. Water is added and immersed in the slurry-like kneaded product.

  And in the state which immersed the end surface 1b side of the sintered compact in the said kneaded material made into said slurry, the pin coated with water-repellent resin was inserted from the end surface 1a (IF), and the inside of the adjacent sealing material 30 After adjusting the position of the tip of the pin so that the position where the surface 30a and the wall surface 4a cross each other is different, it is dried at room temperature to form the sealing material 30.

  Note that the inner surface 30a of the sealing material 30 is formed so that the inner surface 30a of the adjacent sealing material 30 is mutually shaped because the surface of the tip of the pin is transferred to the inner surface 30a of the sealing material 30. In order to obtain different convex shapes, the surface of the tip portion of the pin may be concave shapes having different shapes.

  Also, in order to make the inner surface 30a of the adjacent sealing material 30 any one of a conical shape, a hemispherical shape, and a composite shape thereof, the tip of the pin is made concave and the surface is conical. , Hemispherical shape or a shape in which these are combined.

  Then, after the sealing material 30 is formed, the pins are removed, and the same operation as described above is performed on the end face 1a side of the sintered body to form the sealing material 3.

  After forming the sealing materials 3 and 30 and firing the sintered body again at 1250 ° C to 1700 ° C using a firing furnace such as an electric furnace or a gas furnace, the end faces on both sides of the sintered body are curved convexly Thus, the honeycomb structure 1 of the present invention can be obtained by polishing with a cup wheel type grindstone, a polishing cloth, a polishing pad or the like.

Next, when obtaining the honeycomb structure 1 whose main component is cordierite, the composition of cordierite in the sintered body is 40 to 56 mass% of silicon oxide (SiO ₂ ), aluminum oxide (Al ₂ O _3). Raw materials to be converted into cordierite such as kaolin, calcined kaolin, aluminum oxide, aluminum hydroxide, silicon oxide, talc, or baked talc so that the amount of magnesium is 30 to 46% by mass and magnesium oxide (MgO) is 12 to 16% by mass After obtaining this blended raw material, the steps until obtaining the honeycomb structure 1 are the main components except that the firing temperature is changed from 1250 ° C to 1700 ° C to 1350 ° C to 1450 ° C. Is the same as in the case of aluminum titanate.

In order to obtain the filter 5 carrying the catalyst on the wall surface 4a of the partition wall 4 of the honeycomb structure 1, ruthenium (Ru), rhodium (Rh), palladium (Pd), osmium (Os), iridium (Ir) or platinum. What is necessary is just to bak by the method mentioned above, after immersing the molded object in which the sealing materials 3 and 30 were formed in the kneaded material containing at least any selected from platinum group metals, such as (Pt). When further supporting a catalyst for adsorbing nitrogen oxide (NO _x ), in addition to the platinum group metal, at least one selected from alkali metals, alkaline earth metals or rare earth metals is added to the kneaded product. Add it.

  Then, after the filter 5 is inserted into the cylindrical central portion of the case 7 in a state where the outer peripheral surface of the filter 5 is covered with the heat insulating material layer 6, the truncated cone-shaped case includes an exhaust gas (EG) inlet 8 and an outlet 9. By connecting the both end portions, it is possible to obtain the exhaust gas treatment apparatus of the present invention of the example shown in FIG.

  Examples of the present invention will be specifically described below, but the present invention is not limited to these examples.

First, 100 parts by mass of a component having a molar ratio of titanium oxide (TiO ₂ ) to aluminum oxide (Al ₂ O ₃ ) of 40:60, and a composition formula of (Na _y K _1-y ) AlSi ₃ O ₈ (0 ≦ y ≦
A blended raw material was obtained by blending 5 parts by mass of alkali feldspar (MgO) represented by 1).

  After adding a predetermined amount of graphite as a pore-forming agent to this blended raw material, a plasticizer, a thickener, a lubricant and water were further added, and stirred with a rotary mill to prepare a slurry-like kneaded product. And the kneaded material obtained from the rotary mill was kneaded using a kneader while leaving a part of the kneaded material to obtain a clay.

Next, the above clay is put into an extrusion molding machine having a molding die having an inner diameter of 160 mm for determining the outer diameter of the molded body having slits for forming the partition walls 4 of the honeycomb structure 1, and the pressure is increased. In addition, after forming into a honeycomb shape, it was dried and then cut into a predetermined length.

  And after baking a molded object at 1500 degreeC using an electric furnace, it masks in a checkered pattern so that the part which the sealing material 3b seals on the end surface 1b (OF) side, and the end surface 1b side of a sintered compact Water was added to the kneaded material that had been left to make a slurry and immersed.

  Then, with the end surface 1b side of the sintered body immersed in the slurry kneaded material, a pin coated with a water repellent resin is inserted from the end surface 1a (IF), and the inner surface of the adjacent sealing material 30 is inserted. The position of the tip of the pin was adjusted so that the position where 30a and the wall surface 4a intersected was various, and then dried at room temperature to form the sealing material 30.

  After forming the sealing material 30, the pin is pulled out, masked in a checkered pattern so as to seal a place different from the place sealed on the outflow side in the same way as described above, The sealing material 3 was formed also on the end face 1a side of the sintered body.

  About the position where the inner surface 3a and the wall surface 4a of the adjacent sealing material 3 intersect and the position of the inner surface 30a and the wall surface 4a of the adjacent sealing material 30 intersect, after carrying out a durability test described later, Using a measuring microscope, the magnification was set to 100, and the cross section was observed perpendicular to the axial direction A.

In this embodiment, when the position where the inner surface 3a and the wall surface 4a of the adjacent sealing material 3 intersect and the position of the inner surface 30a and the wall surface 4a of the adjacent sealing material 30 are different, The case where the distance between these positions is 0.2 mm or more and the case where the positions coincide with each other is the case where the distance between these positions is less than 0.2 mm.

  In addition, in order to make the surface of the front-end | tip part of a pin into concave shape and to make the surface of the sealing materials 3 and 30 into a shape as shown in Table 1, it shall be symmetrical with this shape.

  After forming the sealing materials 3 and 30 and firing the sintered body again at 1500 ° C. using an electric furnace, by polishing with a polishing cloth so that the end faces on both sides of the sintered body are curved convexly, Sample No. 1 which is the honeycomb structure 1 is used. 1-13 were obtained. In addition, sample No. which is a comparative example. Regarding No. 14, after the sintered body was fired again at 1500 ° C., the end faces on both sides of the sintered body were not polished and remained flat.

  The state of the end faces on both sides of each sample is as shown in Table 1.

Sample No. Nos. 1 to 14 have a diameter of 144 mm, a length of 117 mm, the porosity of the partition walls 4 and the sealing materials 3 and 30 are 48%, and the density of the flow holes 4 in the cross section in the direction perpendicular to the axial direction is 0.46 / mm ^2, the thickness of the sealing material 3, 30 is 2 to 5 mm, a width of the partition wall 4 has a honeycomb structure is 0.2 mm.

And sample no. 1 to 14 are individually installed in the exhaust gas treatment device 20, and the engine speed and torque are set to 3000 min ⁻¹ and 50 N · m, respectively, and the engine is operated for a predetermined time to introduce exhaust gas into the exhaust gas treatment device 20. Fine particles were collected. Next, when the engine speed is 4000 min ⁻¹ and the temperature of each sample reaches 700 ° C., the engine speed is set to 1050.
A durability test was performed in which fine particles were burned by changing min ⁻¹ and torque to 30 N · m, respectively. This exhaust gas introduction, particulate collection and combustion operations are repeated every time the particulate collection amount increases by 0.1 mg / cm ³ , and the amount of particulate collection until cracking occurs is determined. It is shown in Table 1. A larger value of the collected amount of fine particles means that cracks are less likely to occur and the durability of the honeycomb structure is excellent.

  Note that the cracks were visually confirmed from the inflow side of the exhaust gas treatment apparatus 20 for each sample.

  As can be seen from the results shown in Table 1, Sample No. 13, since the position where the inner surface 3 a and the wall surface 4 a of the adjacent sealing material 3 intersect and the position where the inner surface 30 a and the wall surface 4 a of the adjacent sealing material 30 intersect are the same, It can be seen that the cracks are generated at a stage where the amount of collected fine particles is small since the stress generated at the position is difficult to be relaxed.

  Sample No. In No. 14, since the end faces 1a and 1b on both sides of the honeycomb structure 1 are flat, the stress generated on the end faces 1a and 1b is not easily relieved, so that cracks are generated at a stage where the amount of collected fine particles is small. I understand.

  On the other hand, Sample No. 1 to 12, since the position where the inner surface 3a and the wall surface 4a of the adjacent sealing material 3 intersect and the position of the inner surface 30a and the wall surface 4a of the adjacent sealing material 30 are different from each other, Since the stress generated at these positions is easily relaxed and the end surfaces 1a and 1b on both sides of the honeycomb structure 1 are curved in a convex shape, the stress generated on the end surfaces 1a and 1b is easily relaxed. It can be seen that cracks are not easily generated even when the amount of collected fine particles increases.

  In particular, sample no. 4 to 12, since the inner surface 3 a of the adjacent sealing material 3 and the inner surface 30 a of the adjacent sealing material 30 are both convex shapes having different shapes, heat is repeatedly applied. The stress generated on the inner surfaces of the sealing materials 3 and 30 is a convex shape in which the shapes of the inner surface 3a of the adjacent sealing materials 3 and the inner surface 30a of the adjacent sealing materials 30 are the same. Sample No. It can be seen that cracks are less likely to occur even if the amount of collected fine particles increases because the particles are more easily dispersed than 1 and 2.

  Sample No. 5-12, the inner surface 3a of the adjacent sealing material 3 and the inner surface 30a of the adjacent sealing material 30 are any two types of conical, hemispherical, and a shape in which these are combined. Therefore, even if heat is repeatedly applied, the stress generated on the inner surfaces 3a and 30a of the sealing materials 3 and 30 is the same as the sample No. 3 in which the inner surfaces 3a and 30a are polyhedral. Since it is easier to disperse than 1, it can be seen that cracks are less likely to occur even if the amount of collected fine particles increases.

Further, each of the inner surfaces 3a and 30a of the adjacent sealing materials 3 and 30 has a conical or hemispherical shape. When comparing 5-11, sample no. 6 to 10 are that the angle between the inner surface 3a and the wall surface 4a of the sealing material 3 and the angle between the inner surface 30a and the wall surface 4a of the sealing material 30 are both 5 degrees or more and less than 55 degrees. Sample No. with an angle outside this range. 5 and 11, it can be seen that even if the amount of collected fine particles increases, cracks are less likely to occur.

  Sample No. 1 in which the partition walls 4 and the sealing materials 3 and 30 shown in Table 1 are honeycomb structures made of a sintered body mainly composed of aluminum titanate. 1 and the partition wall 4 and the sealing materials 3 and 30 are sample Nos. 1 and 2 which are honeycomb structures whose main components are the components shown in Table 2. 15-18 were produced.

Sample No. Nos. 1 and 15 to 18 have a diameter of 144 mm, a length of 117 mm, the porosity of each of the partition walls 4 and the sealing materials 3 and 30 is 48%, and the density of the flow holes 4 in the cross section perpendicular to the axial direction is The honeycomb structure 1 was 0.46 pieces / mm ² , the thicknesses of the sealing materials 3 and 30 were ² to 5 mm, and the width of the partition walls 4 was 0.2 mm.

And the thermal shock resistance of the honeycomb structure was evaluated according to JASO M 505-87. Specifically, the sample was placed in an electric furnace maintained at 800 ° C., and after 20 minutes, the sample was taken out and visually checked for cracks.

  The results are shown in Table 2, where Δ is a sample in which a crack was confirmed, and ○ is a sample in which no crack was confirmed.

  As can be seen from the results shown in Table 2, the sample No. Since partition wall 4 is made of a sintered body mainly composed of aluminum titanate, it has high thermal shock resistance. Therefore, even when a sudden temperature change is applied, partition wall 4 is unlikely to crack for a long period of time. I understand.

  Sample No. 16 has a high thermal shock resistance because the sealing materials 3 and 30 are made of a sintered body mainly composed of aluminum titanate, so that the sealing materials 3 and 30 can be used for a long time even if a sudden temperature change is applied. It can be seen that cracks hardly occur.

  In particular, sample no. 1 has a high thermal shock resistance because both the partition wall 4 and the sealing materials 3 and 30 are made of a sintered body containing aluminum titanate as a main component. Therefore, the partition wall 4 and the sealing material can be sealed even if a sudden temperature change is applied. It can be seen that the materials 3 and 30 are less likely to crack over a long period of time.

1: honeycomb structure 2: flow hole 3, 30: sealing material 4: partition wall 5: filter 6: heat insulating material layer 7: case 8: exhaust gas (EG) inlet 9: exhaust gas (EG) outlet
10: Exhaust pipe
20: Exhaust gas treatment equipment

Claims (6)

A honeycomb structure comprising a plurality of flow holes partitioned by a partition wall having an axial wall surface and a sealing material that alternately seals one end and the other end of the plurality of flow holes. The end surfaces on both sides of the honeycomb structure are curved in a convex shape, and in the sealing material disposed around one of the flow holes, the inner surface and the wall surface of the adjacent sealing material position has Tsu Do different intersection of bets, the inner surface shape of the sealing material, conical, hemispherical and these are either convex complexed, the inside of the sealing material adjacent the surface A honeycomb structure having different shapes . The honeycomb structure according to claim 1, wherein an angle formed between an inner surface of the sealing material and the wall surface is 5 degrees or more and less than 55 degrees. The honeycomb structure according to claim 1 or 2 , wherein the partition wall is made of a sintered body mainly composed of aluminum titanate. The honeycomb structure according to any one of claims 1 to 3 , wherein the sealing material is a sintered body mainly composed of aluminum titanate. A filter carrying a catalyst on the wall surface of the partition wall of the honeycomb structure according to any one of claims 1 to 4 , wherein one end of the flow hole not sealed is an inlet, and the flow hole and A filter characterized in that exhaust gas is allowed to pass through the other end of the other through hole that is not sealed through the partition as an outlet, and particulates in the exhaust gas are collected by the partition. An exhaust gas processing apparatus comprising the filter according to claim 5 .

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