WO2016129644A1 - Honeycomb filter - Google Patents

Honeycomb filter Download PDF

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Publication number
WO2016129644A1
WO2016129644A1 PCT/JP2016/053993 JP2016053993W WO2016129644A1 WO 2016129644 A1 WO2016129644 A1 WO 2016129644A1 JP 2016053993 W JP2016053993 W JP 2016053993W WO 2016129644 A1 WO2016129644 A1 WO 2016129644A1
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WO
WIPO (PCT)
Prior art keywords
flow path
channel
catalyst
inlet
side portion
Prior art date
Application number
PCT/JP2016/053993
Other languages
French (fr)
Japanese (ja)
Inventor
友也 黒田
中山　篤
和男 貞岡
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住友化学株式会社
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Publication of WO2016129644A1 publication Critical patent/WO2016129644A1/en

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D39/00—Filtering material for liquid or gaseous fluids
    • B01D39/14—Other self-supporting filtering material ; Other filtering material
    • B01D39/20—Other self-supporting filtering material ; Other filtering material of inorganic material, e.g. asbestos paper, metallic filtering material of non-woven wires
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D46/00—Filters or filtering processes specially modified for separating dispersed particles from gases or vapours
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
    • B01D53/34—Chemical or biological purification of waste gases
    • B01D53/92—Chemical or biological purification of waste gases of engine exhaust gases
    • B01D53/94—Chemical or biological purification of waste gases of engine exhaust gases by catalytic processes
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J29/00—Catalysts comprising molecular sieves
    • B01J29/04—Catalysts comprising molecular sieves having base-exchange properties, e.g. crystalline zeolites
    • B01J29/06—Crystalline aluminosilicate zeolites; Isomorphous compounds thereof
    • B01J35/56—
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N3/00—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
    • F01N3/02—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust
    • F01N3/021—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust by means of filters
    • F01N3/022—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust by means of filters characterised by specially adapted filtering structure, e.g. honeycomb, mesh or fibrous
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N3/00—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
    • F01N3/02—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust
    • F01N3/021—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust by means of filters
    • F01N3/033—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust by means of filters in combination with other devices
    • F01N3/035—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust by means of filters in combination with other devices with catalytic reactors, e.g. catalysed diesel particulate filters

Definitions

  • the present invention relates to a honeycomb filter.
  • a ceramic honeycomb filter that removes particles from a fluid containing particles.
  • An example of such a honeycomb filter carries a ceramic porous substrate having a large number of inlet channels and outlet channels that are parallel to each other, and a catalyst or catalyst held in the pores of the porous substrate.
  • a honeycomb structure is provided (for example, see Patent Document 1 below). Since the porous substrate holds the catalyst or the carrier on which the catalyst is supported, the honeycomb filter can have various functions by the catalyst in addition to the collection of particles.
  • ⁇ ⁇ Pressure loss occurs when the fluid passes through the honeycomb filter. From the viewpoint of reducing the pressure loss when using the honeycomb filter, it is important to sufficiently reduce the initial pressure loss of the honeycomb filter before collecting the particles. In particular, in a honeycomb filter holding a catalyst or a carrier supporting the catalyst, the initial pressure loss tends to be high.
  • the present invention has been made in view of such circumstances, and an object thereof is to provide a honeycomb filter capable of reducing the initial pressure loss.
  • the honeycomb filter according to the present invention includes a honeycomb structure having a plurality of first channels and a plurality of second channels and having a columnar shape.
  • the first flow path is opened at one end face of the honeycomb structure and closed at the other end face
  • the second flow path is closed at one end face of the honeycomb structure and opened at the other end face
  • the second flow path is adjacent to at least one of the first flow paths
  • the partition wall portion between the first flow path and the second flow path in the honeycomb structure is formed on the inner surface of the first flow path. It has irregularities.
  • the honeycomb structure includes a second flow path side portion from the surface of the second flow path to a depth D (where D is half the minimum thickness of the partition wall), the second flow path side portion, and the plurality of the plurality of the honeycomb structures. and a first flow path side portion between the first flow path, the porosity (unit:%) of the first flow path side portion of the epsilon 1, the porosity of the second flow path side portion (unit:% ) Is ⁇ 2 , ⁇ 1 ⁇ 2 is satisfied.
  • irregularities exist on the first channel side of the partition wall, and ⁇ 1 ⁇ 2 is satisfied in the first channel side portion and the second channel side portion of the honeycomb structure. Since the filtration area is increased by the unevenness on the first flow path side, the initial pressure loss can be reduced as compared with the case where there is no unevenness. Furthermore, since the fluid flows so as to concentrate from the plurality of first flow paths toward the second flow path, the average flow velocity is faster in the second flow path side portion than in the first flow path side portion. Therefore, the initial pressure loss can be further reduced by setting ⁇ 1 ⁇ 2 .
  • the honeycomb structure may have a porous base material having pores and a catalyst or a carrier supporting the catalyst held in the pores.
  • the honeycomb filter according to the present invention provides a honeycomb filter in which pressure loss hardly increases even when particles are collected.
  • FIG. 1 is a cross-sectional view taken along the axis of the honeycomb filter according to the first embodiment of the present invention.
  • FIG. 2 is an end view taken along the line II-II in FIG.
  • FIG. 3 is an end view taken along the line III-III in FIG. 4 is a cross-sectional view taken along the line IV-IV in FIG.
  • FIG. 5 is an enlarged view of the partition wall 201Wio of FIG. 6 is an SEM photograph of a cross section perpendicular to the axial direction of the partition wall 201Wio of Example 1.
  • FIG. FIG. 7 is a graph showing pressure loss with respect to the gas flow rate of the filters of Example 1 and Comparative Example 1.
  • FIG. 1 is a cross-sectional view taken along the axis of the honeycomb filter 200 according to the first embodiment.
  • FIGS. 2 to 4 are respectively an inlet side end face 201in, an outlet side end face 201out of the honeycomb filter 200 of FIG. It is an enlarged view of the cross section of a direction center part.
  • the honeycomb filter 200 includes a columnar and porous honeycomb structure 201 having an inlet side end face (one end face) 201in and an outlet side end face (other end face) 201out.
  • the honeycomb structure 201 includes a porous partition wall 201W that extends in the axial direction, that is, between the inlet-side end surface 201in and the outlet-side end surface 201out and forms a large number of through-holes th provided substantially parallel to each other, and each through-hole th. It has the sealing part 201p which closes either one end. As shown in FIG. 1 to FIG.
  • a plurality of inlet flows that are opened at the inlet side end surface 201in and sealed at the outlet side end surface 201out by closing the outlet side end surface 201out of some through holes th with the sealing portion 201p.
  • a path (first flow path) 210 is formed. Further, by closing the inlet side end surface 201in of the remaining through-hole th with the sealing portion 201p, a plurality of outlet channels (second channels) 220 that open to the outlet side end surface 201out and open at the inlet side end surface 201in are formed.
  • second channels second channels
  • the axial length of the honeycomb structure 201 is, for example, 50 to 300 mm.
  • the outer diameter of the honeycomb structure 201 is, for example, 50 to 250 mm.
  • inlet channels 210 and three outlet channels 220 are arranged next to each inlet channel 210.
  • six inlet channels 210 are arranged next to each outlet channel 220.
  • no other outlet channel 220 is arranged next to the outlet channel 220.
  • the cross section substantially perpendicular to the axial direction (longitudinal direction) of the outlet channel 220 is hexagonal.
  • the cross-sectional shape of the outlet channel 220 is such that a fluid containing particles can easily flow from the six inlet channels 210 to the one outlet channel 220 to easily reduce pressure loss during particle deposition.
  • the regular hexagonal shape in which the lengths of the six sides 140 are substantially equal to each other is preferable, but a hexagonal shape in which the lengths of the sides are different from each other and / or a hexagonal shape whose angle is not 60 ° may be used.
  • the inner surface of the inlet channel 210 has a large number of convex portions 210 a extending in the axial direction of the inlet channel 210 and concave portions 210 b provided between the convex portions 210 a. have.
  • one protruding portion 210 a and two recessed portions 210 b are provided on the inlet channel 210 side of the partition wall 201 Wio that separates the inlet channel 210 and the outlet channel 220.
  • One convex portion 210 a and two concave portions 210 b are also provided on the side of each inlet channel 210 of the partition wall portion 201 Wii that separates the channel 210 and the other inlet channel 210. Moreover, between the partition part 201Wii and the partition part 201Wio, one convex part 210a is provided between the two concave parts 210b.
  • each convex portion 210a is not particularly limited, but may be 0.05 to 0.6 mm. If it is less than 0.05 mm, the productivity may be low and the effect may be low. If it exceeds 0.6 mm, productivity may be reduced.
  • the height H of the convex portion 210a is drawn from a straight line L4 that connects the bottom portions Q of the two concave portions 210b on both sides of the convex portion 210a, and from the most straight line L4 in the convex portion 210a.
  • the distant point P can be acquired and obtained as the distance between the straight line L4 and the point P.
  • the distance F between the point P which is the top of the convex portion 210a and the bottom portion Q of the concave portion 210b measured along the straight line L4 is 0.08 to 0.4 mm.
  • the thickness (cell wall thickness) of the partition walls 201Wio and 201Wii is, for example, preferably 0.6 mm or less, more preferably 0.4 mm or less, from the viewpoint of reducing pressure loss. Further, this thickness is preferably 0.1 mm or more, more preferably 0.2 mm or more, even at the minimum thickness portion, from the viewpoint of maintaining high particle collection efficiency and the strength of the honeycomb filter 200.
  • the distance Lio between the inlet channel 210 and the outlet channel 220 that is, the center O210 of the circumscribed circle CC of the inlet channel 210 and the center O220 of the outlet channel 220 (center of the circumscribed circle).
  • the distance Lio is not particularly limited, but can be 1.0 to 2.5 mm.
  • the distance Loo between the pair of opposing sides 140 in the outlet channel 220 is not particularly limited, but can be 0.5 to 2.5 mm.
  • the partition wall 201 ⁇ / b> W is formed of a ceramic porous substrate and a catalyst or a carrier supporting the catalyst held in the pores of the porous substrate. Although the catalyst or the carrier carrying the catalyst is held in the pores of the porous base material, the partition wall 201W is porous as a whole, and gas can flow from one channel to the other channel through the partition wall 201W. It is.
  • Ceramics are aluminum titanate, silicon carbide, cordierite.
  • Aluminum titanate can include magnesium, silicon, and the like.
  • the catalyst examples include a catalyst containing at least one metal element selected from the group consisting of Pt, Pd, Rh, silver, vanadium, chromium, manganese, iron, cobalt, nickel, and copper, or a catalyst made of zeolite particles. is there.
  • the particle size of the catalyst can be, for example, 1 nm to 10 ⁇ m.
  • the support examples include alumina, silica, magnesia, titania, zirconia, ceria, oxides such as La 2 O 3 , BaO, and zeolite, or composite oxide particles containing one or more of these.
  • the particle size of the carrier can be 0.1 to 100 ⁇ m, for example.
  • the porosity is distributed in the honeycomb structure 201.
  • the partition wall 201W of the honeycomb structure 201 has a depth D from the surface of the outlet flow path 220 (where D is the outlet).
  • Outlet channel side portion (second channel side portion) R2 up to half the minimum thickness Dmin of partition wall 201Wio between channel 220 and the plurality of inlet channels 210, outlet channel side portion R2, and a plurality of inlet flows
  • an inlet channel side portion (first channel side portion) R1 between the channel 210 and the channel 210 are indicated by dotted lines L3 in FIGS.
  • the porosity of the inlet flow passage side portion R1 (unit:%) as the epsilon 1
  • the porosity of the outlet channel side portion R2 (Unit:%) when was the epsilon 2
  • 10 ⁇ ⁇ 2 ⁇ 70 and 1 ⁇ ⁇ 2 ⁇ 1 ⁇ 69 can be satisfied.
  • the porosity ⁇ can be easily obtained based on the cross-sectional SEM photograph.
  • the distribution of the porosity of such a honeycomb structure 201 is, for example, by preparing a porous base material with a uniform porosity and selectively holding a catalyst or a carrier in the pores of the inlet channel side portion R1. It can be easily realized. In this case, the concentration per unit volume of the catalyst or the carrier carrying the catalyst in the honeycomb structure 201 is lower in the outlet channel side portion R2 than in the inlet channel side portion R1.
  • a method for manufacturing such a honeycomb filter is shown below.
  • a molded body having a through hole th made of a material containing a ceramic raw material and a pore former is produced by an extrusion molding method.
  • one end or the other end of the through hole is sealed and then fired to obtain a sealed porous substrate having a flow path shape similar to that of the honeycomb structure 201 described above.
  • a slurry containing a catalyst or a carrier supporting the catalyst is prepared, and the entire porous substrate is immersed in the slurry.
  • the porous substrate is pulled up from the slurry, the outlet side end face is sucked, and a gas such as air is flowed in the order of the inlet channel 210, the partition walls, and the outlet channel 220, and the excess slurry is removed from the porous substrate Remove by suction.
  • a gas such as air is flowed in the order of the inlet channel 210, the partition walls, and the outlet channel 220, and the excess slurry is removed from the porous substrate Remove by suction.
  • a carrier carrying a catalyst can be held.
  • the catalyst or the carrier carrying the catalyst can be held not only in the pores but also on the surface of the partition wall.
  • the porosity distribution is formed by the concentration per volume of the catalyst or the carrier being different between the inlet channel side portion R1 and the outlet channel side portion R2.
  • the distribution of the rate can be carried out when the concentration per volume of the catalyst or the carrier is not different between the inlet channel side portion R1 and the outlet channel side portion R2, or even with a filter that does not include the carrier supporting the catalyst or catalyst It is.
  • the concentration of the catalyst or the carrier is spatially uniform. Even in the absence of a catalyst or carrier, the above porosity distribution can be realized.
  • the slurry containing the ceramic raw material is dipped in the same manner as described above. Then, it can be obtained by sucking and firing.
  • the honeycomb filter 200 As shown in FIG. 1, the gas G supplied from the inlet side end face 201in to the inlet flow path 210 passes through the partition wall 201W and reaches the adjacent outlet flow path 220, and the outlet side end face It is discharged from 201out. At this time, particles in the gas G are collected on the surface of the inlet channel 210 and in the pores of the partition walls 201W and removed from the gas G, whereby the honeycomb filter 200 functions as a filter.
  • the honeycomb filter can be a honeycomb filter that collects particles such as soot contained in exhaust gas from an internal combustion engine such as a diesel engine or a gasoline engine.
  • the convex portion 210a and the concave portion 210b exist on the inlet channel 210 side of the partition wall portion 201Wio, and ⁇ in the inlet channel side portion R1 and the outlet channel side portion R2 of the partition wall 201W. meets the 1 ⁇ 2. Since the filtration area increases due to the unevenness of the inlet channel side portion R1, the initial pressure loss is reduced as compared with the case where there is no unevenness. Furthermore, since the fluid flows so as to concentrate from the plurality of inlet channels 210 toward the outlet channel 220, the average flow velocity is higher in the outlet channel side portion R2 than in the inlet channel side portion R1 in the honeycomb structure 201. Get faster. Therefore, the initial pressure loss can be further reduced by setting ⁇ 1 ⁇ 2 .
  • the cross-sectional shapes of the inlet channel 210 and the outlet channel 220 in the honeycomb filter 200 are not limited to the above.
  • the cross-sectional shape of the inlet channel has one convex portion on the inlet channel 210 side of the partition wall 201Wio and two concave portions on both sides of the convex portion.
  • the shape is not particularly limited.
  • the cross-sectional shape of the outlet channel may be a polygon such as a quadrangle or an octagon, or a circle (including an ellipse) other than a hexagon.
  • the outlet channel 220 has six inlet channels 210 adjacent to each other, the other outlet channels 220 are not adjacent to each other, and the inlet channel 210 has two outlet channels 220 and four inlet channels 210 adjacent to each other. I can take it.
  • a plurality of inlet channels 210 are adjacent to each outlet channel 220, and an arrangement in which only the plurality of inlet channels 210 are adjacent and no other outlet channel 220 is adjacent is preferable.
  • the sealing method is not limited to the form in which the end of the through hole is plugged by the sealing portion, but the diameter of the unsealed through hole around the through hole to be sealed is expanded to form a partition wall of the through hole to be sealed.
  • the form which crushes and closes the end of a through-hole may be sufficient.
  • the outer shape of the filter is not particularly limited to a cylindrical shape as long as it is a columnar shape, and may be a prism, for example.
  • the honeycomb filter of the present invention is suitable as a particulate filter (GPF) for gasoline engines. Since the exhaust gas of a gasoline engine has a small amount of soot, if the pressure loss at the initial stage of use as a GPF is low, it can be suitably used as a GPF having a low pressure loss thereafter.
  • GPF particulate filter
  • Example 1 A porous substrate made of aluminum titanate and having the flow channel shape shown in FIGS. 1 to 4 was prepared.
  • the outer diameter is 25.4 mm, the length is 50 mm, the cell density is 300 cpsi, the wall thickness of the thinnest part is 10 mil (0.25 mm), the height H of the convex part of the partition part 201Wio is 150 ⁇ m, and the convex part of the partition part 201Wio
  • the recess F were 180 ⁇ m, the opening ratio at the inlet end was 40%, the opening ratio at the outlet end was 28%, and the porosity of the partition walls was 58% for both ⁇ 1 and ⁇ 2 .
  • a water slurry containing zeolite particles having an average particle size of 2.0 ⁇ m as a catalyst was prepared in a container.
  • the porous substrate was submerged in the water slurry of the vessel. Thereafter, the porous substrate is pulled up from the water slurry, and the outlet side end face is sucked to supply a gas such as air in the order of the inlet channel 210, the partition walls, and the outlet channel 220, and the excess slurry is porous.
  • the material was aspirated and removed. Thereafter, the porous substrate was dried to obtain a honeycomb structure.
  • the catalyst loading was 0.115 g / m 3 per unit volume of the honeycomb structure.
  • FIG. 6 shows an SEM photograph of the vertical cross section of the partition wall 201Wio of the honeycomb structure after drying.
  • a black part is a space
  • a white part is a porous base material
  • a gray part is a catalyst.
  • the porosity ⁇ 1 and ⁇ 2 of the inlet channel side portion R1 and the outlet channel side portion R2 were 34.9% and 43.4%, respectively.
  • an image taken at a magnification of approximately 700 ⁇ m is used, and the total volume of the partition wall and the volume of the space that does not correspond to the porous substrate or catalyst in the partition wall are calculated. By determining the porosity, the porosity was determined.
  • Example 1 The catalyst was mainly held in the outlet channel in the flat partition wall 201Wio in the same manner as in Example 1 except that the inlet channel had no hexagonal shape and no protrusions and recesses were provided. Both ⁇ 1 and ⁇ 2 before applying the catalyst were 58%. ⁇ 1 after application of the catalyst was 33.9%, and ⁇ 2 was 44.3%.
  • DESCRIPTION OF SYMBOLS 200 ... Honeycomb filter, 201in ... Inlet side end surface (one end surface), 201out ... Outlet side end surface (other end surface), 201Wio ... Partition part which separates inlet channel 210 and outlet channel 220, 201 ... Honeycomb structure, 201p ... Sealing , 201W ... partition wall, 210 ... inlet channel (first channel), 210a ... convex portion, 210b ... concave portion, 220 ... outlet channel (second channel), R1 ... inlet channel side portion (first channel side) Part), R2... Outlet channel side part (second channel side part).

Abstract

A partition 201Wio between an inlet passage 210 and an outlet passage 220 in a honeycomb structure 201 has roughness on the inner surface of the inlet passage 210. The honeycomb structure 201 has an outlet passage-side section R2 extending up to a depth D from the surface of the outlet passage 220 (where D is half of the minimum thickness of the partition 201Wio), and an inlet passage-side section R1 between the outlet passage-side section R2 and a plurality of inlet passages 210. If ε1 is the porosity of the inlet passage-side section R1, and ε2 is the porosity of the outlet passage-side section R2, ε1<ε2 is satisfied.

Description

ハニカムフィルタHoneycomb filter
　本発明は、ハニカムフィルタに関する。 The present invention relates to a honeycomb filter.
　従来より、粒子を含む流体から粒子を除去するセラミック製のハニカムフィルタが知られている。このようなハニカムフィルタの一例は、互いに平行な多数の入口流路及び出口流路を有するセラミック製の多孔質基材と、この多孔質基材の細孔内に保持された触媒又は触媒を担持した担体を有する（例えば、下記特許文献１参照）ハニカム構造体を備える。多孔質基材が触媒又は触媒を担持した担体を保持することで、ハニカムフィルタは粒子の捕集に加えて触媒による様々な機能を追加して有することができる。 Conventionally, a ceramic honeycomb filter that removes particles from a fluid containing particles is known. An example of such a honeycomb filter carries a ceramic porous substrate having a large number of inlet channels and outlet channels that are parallel to each other, and a catalyst or catalyst held in the pores of the porous substrate. A honeycomb structure is provided (for example, see Patent Document 1 below). Since the porous substrate holds the catalyst or the carrier on which the catalyst is supported, the honeycomb filter can have various functions by the catalyst in addition to the collection of particles.
特表２０１３－５３０３３２号公報Special table 2013-530332 gazette
　流体がハニカムフィルタを通過する際には圧力損失を生じる。ハニカムフィルタの使用時の圧力損失を低くする観点から、粒子を捕集する前のハニカムフィルタの初期の圧力損失を十分低くすることが重要である。特に、触媒又は触媒を担持した担体を保持したハニカムフィルタでは初期の圧力損失が高くなりやすい。 圧 力 Pressure loss occurs when the fluid passes through the honeycomb filter. From the viewpoint of reducing the pressure loss when using the honeycomb filter, it is important to sufficiently reduce the initial pressure loss of the honeycomb filter before collecting the particles. In particular, in a honeycomb filter holding a catalyst or a carrier supporting the catalyst, the initial pressure loss tends to be high.
　本発明は、このような事情に鑑みてなされたものであり、初期の圧力損失を低減できるハニカムフィルタを提供することを目的とする。 The present invention has been made in view of such circumstances, and an object thereof is to provide a honeycomb filter capable of reducing the initial pressure loss.
　本発明に係るハニカムフィルタは、複数の第１流路及び複数の第２流路を有し、柱状形状を有するハニカム構造体を備える。
　前記第１流路は、前記ハニカム構造体の一端面で開口されて他端面で閉じられ、前記第２流路は、前記ハニカム構造体の一端面で閉じられて前記他端面で開口され、前記第２流路は少なくとも１つの前記第１流路と隣り合い、前記ハニカム構造体における前記第１流路と前記第２流路との間にある隔壁部は、前記第１流路の内面に凹凸を有する。
　前記ハニカム構造体は、前記第２流路の表面から深さＤ（ただし、Ｄは前記隔壁部の最小厚みの半分）までの第２流路側部分と、前記第２流路側部分と前記複数の第１流路との間の第１流路側部分とを有し、前記第１流路側部分の空隙率（単位：％）をε１とし、前記第２流路側部分の空隙率（単位：％）をε２としたときに、ε１＜ε２を満たす。 The honeycomb filter according to the present invention includes a honeycomb structure having a plurality of first channels and a plurality of second channels and having a columnar shape.
The first flow path is opened at one end face of the honeycomb structure and closed at the other end face, and the second flow path is closed at one end face of the honeycomb structure and opened at the other end face, The second flow path is adjacent to at least one of the first flow paths, and the partition wall portion between the first flow path and the second flow path in the honeycomb structure is formed on the inner surface of the first flow path. It has irregularities.
The honeycomb structure includes a second flow path side portion from the surface of the second flow path to a depth D (where D is half the minimum thickness of the partition wall), the second flow path side portion, and the plurality of the plurality of the honeycomb structures. and a first flow path side portion between the first flow path, the porosity (unit:%) of the first flow path side portion of the epsilon 1, the porosity of the second flow path side portion (unit:% ) Is ε 2 , ε 1 <ε 2 is satisfied.
　本発明によれば、隔壁部の第１流路側に凸凹が存在し、かつ、ハニカム構造体の第１流路側部分及び第２流路側部分においてε１＜ε２を満たしている。第１流路側の凹凸によってろ過面積が増大するので凹凸がない場合に比べて初期圧力損失を低減できる。さらに、流体は、複数の第１流路から第２流路に向かって集中するように流れるので、第１流路側部分よりも第２流路側部分の方が、平均流速が早くなる。したがって、ε１＜ε２とすることにより、初期の圧力損失をより一層低減させることができる。 According to the present invention, irregularities exist on the first channel side of the partition wall, and ε 1 <ε 2 is satisfied in the first channel side portion and the second channel side portion of the honeycomb structure. Since the filtration area is increased by the unevenness on the first flow path side, the initial pressure loss can be reduced as compared with the case where there is no unevenness. Furthermore, since the fluid flows so as to concentrate from the plurality of first flow paths toward the second flow path, the average flow velocity is faster in the second flow path side portion than in the first flow path side portion. Therefore, the initial pressure loss can be further reduced by setting ε 1 <ε 2 .
　ここで、１０≦ε２≦７０、かつ、１≦ε２－ε１≦６９であることができる。 Here, 10 ≦ ε 2 ≦ 70 and 1 ≦ ε 2 −ε 1 ≦ 69 can be satisfied.
　また、前記ハニカム構造体は、細孔を有する多孔質基材と、前記細孔内に保持された、触媒、又は、触媒を担持した担体を有することができる。 The honeycomb structure may have a porous base material having pores and a catalyst or a carrier supporting the catalyst held in the pores.
　本発明に係るハニカムフィルタによれば、粒子を捕集しても圧力損失が上昇しにくいハニカムフィルタが提供される。 The honeycomb filter according to the present invention provides a honeycomb filter in which pressure loss hardly increases even when particles are collected.
図１は、本発明の第１実施形態に係るハニカムフィルタの軸に沿う断面図である。FIG. 1 is a cross-sectional view taken along the axis of the honeycomb filter according to the first embodiment of the present invention. 図２は、図１のＩＩ－ＩＩ端面図である。FIG. 2 is an end view taken along the line II-II in FIG. 図３は、図１のＩＩＩ－ＩＩＩ端面図である。FIG. 3 is an end view taken along the line III-III in FIG. 図４は、図１のＩＶ－ＩＶ断面図である。4 is a cross-sectional view taken along the line IV-IV in FIG. 図５は、図４の隔壁部２０１Ｗｉｏの拡大図である。FIG. 5 is an enlarged view of the partition wall 201Wio of FIG. 図６は、実施例１の隔壁部２０１Ｗｉｏの軸方向に垂直な断面のＳＥＭ写真である。6 is an SEM photograph of a cross section perpendicular to the axial direction of the partition wall 201Wio of Example 1. FIG. 図７は、実施例１及び比較例１のフィルタのガス流量に対する圧力損失を示すグラフである。FIG. 7 is a graph showing pressure loss with respect to the gas flow rate of the filters of Example 1 and Comparative Example 1.
　以下、必要に応じて図面を参照しつつ、本発明を実施するための形態について詳細に説明する。ただし、本発明は以下の実施形態に限定されるものではない。なお、図面中、同一要素には同一符号を付すこととし、重複する説明は省略する。また、図面の寸法比率は図示の比率に限られるものではない。 Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the drawings as necessary. However, the present invention is not limited to the following embodiments. In the drawings, the same elements are denoted by the same reference numerals, and redundant description is omitted. Further, the dimensional ratios in the drawings are not limited to the illustrated ratios.
（第１実施形態）
　図１は、第１実施形態に係るハニカムフィルタ２００の軸に沿う断面図であり、図２～図４は、それぞれ図１のハニカムフィルタ２００の入口側端面２０１ｉｎ、出口側端面２０１ｏｕｔ、及び、軸方向中央部の断面の拡大図である。 (First embodiment)
FIG. 1 is a cross-sectional view taken along the axis of the honeycomb filter 200 according to the first embodiment. FIGS. 2 to 4 are respectively an inlet side end face 201in, an outlet side end face 201out of the honeycomb filter 200 of FIG. It is an enlarged view of the cross section of a direction center part.
　ハニカムフィルタ２００は、図１に示すように、入口側端面（一端面）２０１ｉｎ及び出口側端面（他端面）２０１ｏｕｔを有する柱状で多孔質のハニカム構造体２０１を備える。ハニカム構造体２０１は、その軸方向すなわち入口側端面２０１ｉｎ及び出口側端面２０１ｏｕｔ間に延びて互いに略平行に設けられた多数の貫通孔ｔｈを形成する多孔質の隔壁２０１Ｗ、及び、各貫通孔ｔｈのいずれか一端を閉じる封口部２０１ｐを有している。図１～図３に示すように、一部の貫通孔ｔｈの出口側端面２０１ｏｕｔを封口部２０１ｐで閉じることにより、入口側端面２０１ｉｎに開口して出口側端面２０１ｏｕｔで封口された複数の入口流路（第１流路）２１０が形成されている。また、残りの貫通孔ｔｈの入口側端面２０１ｉｎを封口部２０１ｐで閉じることにより、出口側端面２０１ｏｕｔに開口して入口側端面２０１ｉｎで開口する複数の出口流路（第２流路）２２０が形成されている。 As shown in FIG. 1, the honeycomb filter 200 includes a columnar and porous honeycomb structure 201 having an inlet side end face (one end face) 201in and an outlet side end face (other end face) 201out. The honeycomb structure 201 includes a porous partition wall 201W that extends in the axial direction, that is, between the inlet-side end surface 201in and the outlet-side end surface 201out and forms a large number of through-holes th provided substantially parallel to each other, and each through-hole th. It has the sealing part 201p which closes either one end. As shown in FIG. 1 to FIG. 3, a plurality of inlet flows that are opened at the inlet side end surface 201in and sealed at the outlet side end surface 201out by closing the outlet side end surface 201out of some through holes th with the sealing portion 201p. A path (first flow path) 210 is formed. Further, by closing the inlet side end surface 201in of the remaining through-hole th with the sealing portion 201p, a plurality of outlet channels (second channels) 220 that open to the outlet side end surface 201out and open at the inlet side end surface 201in are formed. Has been.
　ハニカム構造体２０１の軸方向長さは、例えば５０～３００ｍｍである。ハニカム構造体２０１の外径は、例えば５０～２５０ｍｍである。 The axial length of the honeycomb structure 201 is, for example, 50 to 300 mm. The outer diameter of the honeycomb structure 201 is, for example, 50 to 250 mm.
　本実施形態では、図４に示すように、各入口流路２１０の隣には、３つの他の入口流路２１０と３つの出口流路２２０とが配置されている。一方、各出口流路２２０の隣には、６つの入口流路２１０が配置されている。出口流路２２０の隣に、他の出口流路２２０が配置されることはない。 In the present embodiment, as shown in FIG. 4, three other inlet channels 210 and three outlet channels 220 are arranged next to each inlet channel 210. On the other hand, six inlet channels 210 are arranged next to each outlet channel 220. Next to the outlet channel 220, no other outlet channel 220 is arranged.
　図４に示すように、出口流路２２０の軸方向（長手方向）に略垂直な断面は、六角形状である。出口流路２２０の断面形状は、粒子を含む流体を６つの入口流路２１０から１つの出口流路２２０へ均等に流れ易くして、粒子の堆積時の圧力損失を低減し易くする観点から、６つの辺１４０の長さが互いに略等しい正六角形状が好ましいが、辺の長さが互いに異なる六角形状、及び／又は、角度が６０°ではない六角形であってもよい。 As shown in FIG. 4, the cross section substantially perpendicular to the axial direction (longitudinal direction) of the outlet channel 220 is hexagonal. The cross-sectional shape of the outlet channel 220 is such that a fluid containing particles can easily flow from the six inlet channels 210 to the one outlet channel 220 to easily reduce pressure loss during particle deposition. The regular hexagonal shape in which the lengths of the six sides 140 are substantially equal to each other is preferable, but a hexagonal shape in which the lengths of the sides are different from each other and / or a hexagonal shape whose angle is not 60 ° may be used.
　続いて隔壁２０１Ｗの詳細を説明する。本実施形態では、入口流路２１０の内面は、図１及び図４に示すように、入口流路２１０の軸方向に延びる多数の凸部２１０ａと、凸部２１０ａ間にそれぞれ設けられた凹部２１０ｂを有している。図４に示すように、本実施形態においては、入口流路２１０及び出口流路２２０を隔てる隔壁部２０１Ｗｉｏの入口流路２１０側に１つの凸部２１０ａ及び２つの凹部２１０ｂが設けられると共に、入口流路２１０及び他の入口流路２１０を隔てる隔壁部２０１Ｗｉｉの各入口流路２１０側にも１つの凸部２１０ａ及び２つの凹部２１０ｂが設けられている。また、隔壁部２０１Ｗｉｉと隔壁部２０１Ｗｉｏとの間において、２つの凹部２１０ｂの間に１つの凸部２１０ａが設けられている。 Next, details of the partition wall 201W will be described. In the present embodiment, as shown in FIGS. 1 and 4, the inner surface of the inlet channel 210 has a large number of convex portions 210 a extending in the axial direction of the inlet channel 210 and concave portions 210 b provided between the convex portions 210 a. have. As shown in FIG. 4, in the present embodiment, one protruding portion 210 a and two recessed portions 210 b are provided on the inlet channel 210 side of the partition wall 201 Wio that separates the inlet channel 210 and the outlet channel 220. One convex portion 210 a and two concave portions 210 b are also provided on the side of each inlet channel 210 of the partition wall portion 201 Wii that separates the channel 210 and the other inlet channel 210. Moreover, between the partition part 201Wii and the partition part 201Wio, one convex part 210a is provided between the two concave parts 210b.
　各凸部２１０ａの高さは特に限定されないが、０．０５～０．６ｍｍとすることが出来る。０．０５ｍｍ未満では生産性が低く効果が低くなる場合がある。また、０．６ｍｍ超では生産性が低下する場合がある。 The height of each convex portion 210a is not particularly limited, but may be 0.05 to 0.6 mm. If it is less than 0.05 mm, the productivity may be low and the effect may be low. If it exceeds 0.6 mm, productivity may be reduced.
　ここで、凸部２１０ａの高さＨは、図４に示すように、凸部２１０ａの両側の２つの凹部２１０ｂの最底部Ｑ同士を結ぶ直線Ｌ４を描き、凸部２１０ａの内最も直線Ｌ４から離れた点Ｐを取得し、直線Ｌ４と点Ｐとの距離として求めることができる。 Here, as shown in FIG. 4, the height H of the convex portion 210a is drawn from a straight line L4 that connects the bottom portions Q of the two concave portions 210b on both sides of the convex portion 210a, and from the most straight line L4 in the convex portion 210a. The distant point P can be acquired and obtained as the distance between the straight line L4 and the point P.
　直線Ｌ４に沿って測定した凸部２１０ａの頂となる点Ｐと凹部２１０ｂの最底部Ｑとの距離Ｆが０．０８～０．４ｍｍであることが好ましい。 It is preferable that the distance F between the point P which is the top of the convex portion 210a and the bottom portion Q of the concave portion 210b measured along the straight line L4 is 0.08 to 0.4 mm.
　隔壁部２０１Ｗｉｏ、２０１Ｗｉｉの厚み（セル壁厚）は、例えば、圧力損失低減の観点から、最低厚み部が、０．６ｍｍ以下が好ましく、０．４ｍｍ以下がより好ましい。また、この厚みは、粒子の捕集効率及びハニカムフィルタ２００の強度を高く維持する観点から、最低厚み部でも０．１ｍｍ以上が好ましく、０．２ｍｍ以上がより好ましい。 The thickness (cell wall thickness) of the partition walls 201Wio and 201Wii is, for example, preferably 0.6 mm or less, more preferably 0.4 mm or less, from the viewpoint of reducing pressure loss. Further, this thickness is preferably 0.1 mm or more, more preferably 0.2 mm or more, even at the minimum thickness portion, from the viewpoint of maintaining high particle collection efficiency and the strength of the honeycomb filter 200.
　図４に示すように、入口流路２１０と出口流路２２０との距離Ｌｉｏ、すなわち、入口流路２１０の外接円ＣＣの中心Ｏ２１０と出口流路２２０の中心Ｏ２２０（外接円の中心）との距離Ｌｉｏは、特に限定されないが、１．０～２．５ｍｍとすることができる。また、出口流路２２０における一対の対向する辺１４０間の距離Ｌｏｏは、特に限定されないが、０．５～２．５ｍｍとすることができる。 As shown in FIG. 4, the distance Lio between the inlet channel 210 and the outlet channel 220, that is, the center O210 of the circumscribed circle CC of the inlet channel 210 and the center O220 of the outlet channel 220 (center of the circumscribed circle). The distance Lio is not particularly limited, but can be 1.0 to 2.5 mm. Further, the distance Loo between the pair of opposing sides 140 in the outlet channel 220 is not particularly limited, but can be 0.5 to 2.5 mm.
　隔壁２０１Ｗは、セラミクス製の多孔質基材と、多孔質基材の細孔内に保持された、触媒、又は、触媒を担持した担体から形成されている。多孔質基材の細孔には触媒又は触媒を担持した担体が保持されているが、隔壁２０１Ｗは全体として多孔質であり、隔壁２０１Ｗを介して一方流路から他方流路にガスが流通可能である。 The partition wall 201 </ b> W is formed of a ceramic porous substrate and a catalyst or a carrier supporting the catalyst held in the pores of the porous substrate. Although the catalyst or the carrier carrying the catalyst is held in the pores of the porous base material, the partition wall 201W is porous as a whole, and gas can flow from one channel to the other channel through the partition wall 201W. It is.
　セラミクスの例は、チタン酸アルミニウム、炭化ケイ素、コージェライトである。チタン酸アルミニウムは、マグネシウムやケイ素などを含むことができる。 Examples of ceramics are aluminum titanate, silicon carbide, cordierite. Aluminum titanate can include magnesium, silicon, and the like.
　触媒の例は、Ｐｔ、Ｐｄ、Ｒｈ、銀、バナジウム、クロム、マンガン、鉄、コバルト、ニッケル、銅からなる群より選択される少なくとも１つの金属元素を含む触媒、又は、ゼオライト粒子からなる触媒である。触媒の粒径は、例えば、１ｎｍ～１０μｍとすることができる。 Examples of the catalyst include a catalyst containing at least one metal element selected from the group consisting of Pt, Pd, Rh, silver, vanadium, chromium, manganese, iron, cobalt, nickel, and copper, or a catalyst made of zeolite particles. is there. The particle size of the catalyst can be, for example, 1 nm to 10 μm.
　担体の例は、アルミナ、シリカ、マグネシア、チタニア、ジルコニア、セリア、Ｌａ２Ｏ３、ＢａＯ、ゼオライト等の酸化物、あるいは、これらの内の１種以上を含む複合酸化物の粒子である。担体の粒径は、例えば、０．１～１００μｍとすることができる。 Examples of the support are alumina, silica, magnesia, titania, zirconia, ceria, oxides such as La 2 O 3 , BaO, and zeolite, or composite oxide particles containing one or more of these. The particle size of the carrier can be 0.1 to 100 μm, for example.
　本実施形態では、ハニカム構造体２０１において空隙率に分布を生じている。具体的には、図５に示すように、ハニカム構造体２０１の流路に垂直な断面において、ハニカム構造体２０１の隔壁２０１Ｗは、出口流路２２０の表面から深さＤ（ただし、Ｄは出口流路２２０と複数の入口流路２１０との間の隔壁部２０１Ｗｉｏの最小厚みＤｍｉｎの半分）までの出口流路側部分（第２流路側部分）Ｒ２と、出口流路側部分Ｒ２と複数の入口流路２１０との間の入口流路側部分（第１流路側部分）Ｒ１とを有する。これらの境界を図４及び図５に点線Ｌ３で示す。そして、入口流路側部分Ｒ１の空隙率（単位：％）をε１とし、出口流路側部分Ｒ２の空隙率（単位：％）をε２としたときに、ε１＜ε２を満たす。 In the present embodiment, the porosity is distributed in the honeycomb structure 201. Specifically, as shown in FIG. 5, in the cross section perpendicular to the flow path of the honeycomb structure 201, the partition wall 201W of the honeycomb structure 201 has a depth D from the surface of the outlet flow path 220 (where D is the outlet). Outlet channel side portion (second channel side portion) R2 up to half the minimum thickness Dmin of partition wall 201Wio between channel 220 and the plurality of inlet channels 210, outlet channel side portion R2, and a plurality of inlet flows And an inlet channel side portion (first channel side portion) R1 between the channel 210 and the channel 210. These boundaries are indicated by dotted lines L3 in FIGS. The porosity of the inlet flow passage side portion R1 (unit:%) as the epsilon 1, the porosity of the outlet channel side portion R2 (Unit:%) when was the epsilon 2, satisfy ε 1 <ε 2.
　ここで、１０≦ε２≦７０、かつ、１≦ε２－ε１≦６９であることができる。好ましくは５≦ε２－ε１≦５０であり、さらに好ましくは７≦ε２－ε１≦３０である。ここで、空隙率εは、断面ＳＥＭ写真に基づいて容易に取得することができる。 Here, 10 ≦ ε 2 ≦ 70 and 1 ≦ ε 2 −ε 1 ≦ 69 can be satisfied. Preferably 5 ≦ ε 2 −ε 1 ≦ 50, and more preferably 7 ≦ ε 2 −ε 1 ≦ 30. Here, the porosity ε can be easily obtained based on the cross-sectional SEM photograph.
　このようなハニカム構造体２０１の空隙率の分布は、例えば、空隙率が均一の多孔質基材を用意し、入口流路側部分Ｒ１の細孔内に選択的に触媒又は担体を保持させることにより容易に実現できる。この場合、ハニカム構造体２０１における触媒又は触媒を担持した担体の見かけの体積あたりの濃度は、入口流路側部分Ｒ１よりも出口流路側部分Ｒ２のほうが低くなる。 The distribution of the porosity of such a honeycomb structure 201 is, for example, by preparing a porous base material with a uniform porosity and selectively holding a catalyst or a carrier in the pores of the inlet channel side portion R1. It can be easily realized. In this case, the concentration per unit volume of the catalyst or the carrier carrying the catalyst in the honeycomb structure 201 is lower in the outlet channel side portion R2 than in the inlet channel side portion R1.
　このようなハニカムフィルタの製造方法の一例を以下に示す。公知の方法に従って、セラミック原料及び造孔剤を含む材料で貫通孔ｔｈを有する成形体を押し出し成形法で製造する。続いて、貫通孔の一端又は他端を封口し、その後、焼成して、上述のハニカム構造体２０１と同様の流路形状を有する封口された多孔質基材を得る。続いて、触媒又は触媒を担持した担体を含むスラリーを用意し、多孔質基材の全体をスラリー中に浸漬する。その後、多孔質基材をスラリーから引き上げ、出口側端面を吸引して、空気などのガスを入口流路２１０、隔壁、及び、出口流路２２０内の順に流し、余分なスラリーを多孔質基材から吸引して除去する。これにより、多孔質基材の隔壁内に残るスラリーの大部分は、吸引側の逆側である入口流路２１０の近傍に偏在することになり、入口流路２１０の近傍に選択的に触媒又は触媒を担持した担体を保持させることができる。 An example of a method for manufacturing such a honeycomb filter is shown below. According to a known method, a molded body having a through hole th made of a material containing a ceramic raw material and a pore former is produced by an extrusion molding method. Subsequently, one end or the other end of the through hole is sealed and then fired to obtain a sealed porous substrate having a flow path shape similar to that of the honeycomb structure 201 described above. Subsequently, a slurry containing a catalyst or a carrier supporting the catalyst is prepared, and the entire porous substrate is immersed in the slurry. Thereafter, the porous substrate is pulled up from the slurry, the outlet side end face is sucked, and a gas such as air is flowed in the order of the inlet channel 210, the partition walls, and the outlet channel 220, and the excess slurry is removed from the porous substrate Remove by suction. As a result, most of the slurry remaining in the partition walls of the porous substrate is unevenly distributed in the vicinity of the inlet channel 210 on the opposite side of the suction side. A carrier carrying a catalyst can be held.
　なお、触媒又は触媒を担持した担体は、細孔内だけでなく隔壁部の表面上にも保持されうる。 Note that the catalyst or the carrier carrying the catalyst can be held not only in the pores but also on the surface of the partition wall.
　また、上記例では、入口流路側部分Ｒ１と出口流路側部分Ｒ２との間で触媒又は担体の体積あたりの濃度が異なっていることによって空隙率の分布が形成されているが、このような空隙率の分布は、入口流路側部分Ｒ１と出口流路側部分Ｒ２との間で触媒又は担体の体積あたりの濃度が異なっていない場合、あるいは、触媒又は触媒を担持した担体を含まないフィルタでも実施可能である。例えば、触媒又は担体を保持する前の多孔質基材の空隙率に入口流路側部分Ｒ１と出口流路側部分Ｒ２との間で上述の差異があれば、触媒又は担体の濃度が空間的に均一であっても、あるいは、触媒又は担体を有さなくても上述の空隙率の分布を実現でき。このようなハニカム構造体は、入口流路側部分Ｒ１と出口流路側部分Ｒ２との空隙率が同一の焼結済の多孔質基材を得た後、セラミクス原料を含むスラリーを上記と同様に浸漬し、吸引し、焼成等すれば得られる。 Further, in the above example, the porosity distribution is formed by the concentration per volume of the catalyst or the carrier being different between the inlet channel side portion R1 and the outlet channel side portion R2. The distribution of the rate can be carried out when the concentration per volume of the catalyst or the carrier is not different between the inlet channel side portion R1 and the outlet channel side portion R2, or even with a filter that does not include the carrier supporting the catalyst or catalyst It is. For example, if the porosity of the porous substrate before holding the catalyst or the carrier has the above difference between the inlet channel side portion R1 and the outlet channel side portion R2, the concentration of the catalyst or the carrier is spatially uniform. Even in the absence of a catalyst or carrier, the above porosity distribution can be realized. In such a honeycomb structure, after obtaining a sintered porous substrate having the same porosity in the inlet channel side portion R1 and the outlet channel side portion R2, the slurry containing the ceramic raw material is dipped in the same manner as described above. Then, it can be obtained by sucking and firing.
　このようなハニカムフィルタ２００では、図１に示すように、入口側端面２０１ｉｎから入口流路２１０に供給されたガスＧが隔壁２０１Ｗを通過して隣の出口流路２２０に到達し、出口側端面２０１ｏｕｔから排出される。このとき、ガスＧ中の粒子が入口流路２１０の表面や隔壁２０１Ｗの細孔内に捕集されてガスＧから除去されることにより、ハニカムフィルタ２００はフィルタとして機能する。上記ハニカムフィルタは、例えば、ディーゼルエンジン、ガソリンエンジン等の内燃機関からの排ガス中に含まれるすす等の粒子を捕集するハニカムフィルタとなることができる。 In such a honeycomb filter 200, as shown in FIG. 1, the gas G supplied from the inlet side end face 201in to the inlet flow path 210 passes through the partition wall 201W and reaches the adjacent outlet flow path 220, and the outlet side end face It is discharged from 201out. At this time, particles in the gas G are collected on the surface of the inlet channel 210 and in the pores of the partition walls 201W and removed from the gas G, whereby the honeycomb filter 200 functions as a filter. The honeycomb filter can be a honeycomb filter that collects particles such as soot contained in exhaust gas from an internal combustion engine such as a diesel engine or a gasoline engine.
　本実施形態に係るハニカムフィルタ２００によれば、隔壁部２０１Ｗｉｏの入口流路２１０側に凸部２１０ａ及び凹部２１０ｂが存在し、かつ、隔壁２０１Ｗの入口流路側部分Ｒ１及び出口流路側部分Ｒ２においてε１＜ε２を満たしている。入口流路側部分Ｒ１の凹凸によってろ過面積が増大するので凹凸がない場合に比べて初期圧力損失が低減される。さらに、流体は、複数の入口流路２１０から出口流路２２０に向かって集中するように流れるので、ハニカム構造体２０１において入口流路側部分Ｒ１よりも出口流路側部分Ｒ２の方が、平均流速が早くなる。したがって、ε１＜ε２をとすることにより、初期の圧力損失をより一層低減させることができる。 According to the honeycomb filter 200 according to the present embodiment, the convex portion 210a and the concave portion 210b exist on the inlet channel 210 side of the partition wall portion 201Wio, and ε in the inlet channel side portion R1 and the outlet channel side portion R2 of the partition wall 201W. meets the 1 <ε 2. Since the filtration area increases due to the unevenness of the inlet channel side portion R1, the initial pressure loss is reduced as compared with the case where there is no unevenness. Furthermore, since the fluid flows so as to concentrate from the plurality of inlet channels 210 toward the outlet channel 220, the average flow velocity is higher in the outlet channel side portion R2 than in the inlet channel side portion R1 in the honeycomb structure 201. Get faster. Therefore, the initial pressure loss can be further reduced by setting ε 1 <ε 2 .
　なお、本発明は必ずしも上述した実施形態に限定されるものではなく、その要旨を逸脱しない範囲で様々な変更が可能である。 In addition, this invention is not necessarily limited to embodiment mentioned above, A various change is possible in the range which does not deviate from the summary.
　例えば、ハニカムフィルタ２００において入口流路２１０及び出口流路２２０の断面形状は、上記に限られるものではない。上記実施形態では、入口流路の断面形状は、隔壁部２０１Ｗｉｏの入口流路２１０側に１つの凸部及び凸部の両側に２つの凹部を有しているが、凹部および凸部の数や形状も特に限定はない。 For example, the cross-sectional shapes of the inlet channel 210 and the outlet channel 220 in the honeycomb filter 200 are not limited to the above. In the above embodiment, the cross-sectional shape of the inlet channel has one convex portion on the inlet channel 210 side of the partition wall 201Wio and two concave portions on both sides of the convex portion. The shape is not particularly limited.
　また、出口流路の断面形状は、６角形以外にも、例えば、４角形、８角形などの多角形や、円形（楕円形含む）にすることもできる。 Further, the cross-sectional shape of the outlet channel may be a polygon such as a quadrangle or an octagon, or a circle (including an ellipse) other than a hexagon.
　また、出口流路２２０の隣に少なくとも１つの入口流路２１０が配置されていればよく、出口流路２２０に隣接して配置される入口流路２１０及び出口流路２２０の数や、入口流路２１０に隣接して配置される入口流路２１０及び出口流路２２０の数も任意に変更できる。例えば、出口流路２２０に６つの入口流路２１０が隣接し他の出口流路２２０が隣接せず、入口流路２１０に２つの出口流路２２０及び４つの入口流路２１０が隣接する形態を取ることが出来る。特に、各出口流路２２０には複数の入口流路２１０が隣接していることが好ましく、複数の入口流路２１０のみが隣接して他の出口流路２２０が隣接しない配置が好適である。 In addition, it is only necessary that at least one inlet channel 210 be arranged next to the outlet channel 220, and the number of inlet channels 210 and outlet channels 220 arranged adjacent to the outlet channel 220, The number of inlet channels 210 and outlet channels 220 arranged adjacent to the channel 210 can also be arbitrarily changed. For example, the outlet channel 220 has six inlet channels 210 adjacent to each other, the other outlet channels 220 are not adjacent to each other, and the inlet channel 210 has two outlet channels 220 and four inlet channels 210 adjacent to each other. I can take it. In particular, it is preferable that a plurality of inlet channels 210 are adjacent to each outlet channel 220, and an arrangement in which only the plurality of inlet channels 210 are adjacent and no other outlet channel 220 is adjacent is preferable.
　また、封口方法も、貫通孔の一端に封口部により栓をする形態に限定されず、封口すべき貫通孔の周りの封口されない貫通孔の径を拡張して、封口すべき貫通孔の隔壁をつぶして貫通孔の一端を閉鎖する形態でもよい。 Further, the sealing method is not limited to the form in which the end of the through hole is plugged by the sealing portion, but the diameter of the unsealed through hole around the through hole to be sealed is expanded to form a partition wall of the through hole to be sealed. The form which crushes and closes the end of a through-hole may be sufficient.
　また、フィルタの外形形状も柱状形状であれば特に、円柱状に限定されず、例えば、角柱等でもよい。 In addition, the outer shape of the filter is not particularly limited to a cylindrical shape as long as it is a columnar shape, and may be a prism, for example.
　本発明のハニカムフィルタは、ガソリンエンジン向けのパティキュレートフィルター（ＧＰＦ）として好適である。ガソリンエンジンの排気ガスは煤の量が少ないので、ＧＰＦとしての使用の初期段階での圧力損失が低ければ、その後も低い圧力損失を持つＧＰＦとして好適に使用できると考えられる。 The honeycomb filter of the present invention is suitable as a particulate filter (GPF) for gasoline engines. Since the exhaust gas of a gasoline engine has a small amount of soot, if the pressure loss at the initial stage of use as a GPF is low, it can be suitably used as a GPF having a low pressure loss thereafter.
　以下、本発明を実施例により更に詳細に説明するが、本発明はこれらの実施例に限定されるものではない。 Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.
（実施例１）
　チタン酸アルミニウム製の図１～図４に示す流路形状を有する多孔質基材を用意した。外径は２５．４ｍｍ、長さは５０ｍｍ、セル密度は３００ｃｐｓｉ、最薄部の壁厚みは１０ｍｉｌ（０．２５ｍｍ）、隔壁部２０１Ｗｉｏの凸部の高さＨは１５０μｍ、隔壁部２０１Ｗｉｏの凸部と凹部との距離Ｆは１８０μｍ、入口端の開口率４０％、出口端の開口率２８％、隔壁の空隙率はε１及びε２の両方とも５８％であった。 (Example 1)
A porous substrate made of aluminum titanate and having the flow channel shape shown in FIGS. 1 to 4 was prepared. The outer diameter is 25.4 mm, the length is 50 mm, the cell density is 300 cpsi, the wall thickness of the thinnest part is 10 mil (0.25 mm), the height H of the convex part of the partition part 201Wio is 150 μm, and the convex part of the partition part 201Wio And the recess F were 180 μm, the opening ratio at the inlet end was 40%, the opening ratio at the outlet end was 28%, and the porosity of the partition walls was 58% for both ε 1 and ε 2 .
　触媒として平均粒径２．０μｍゼオライト粒子を含む水スラリーを容器内に用意した。当該容器の水スラリー中に多孔質基材を沈めた。その後、多孔質基材を水スラリーから引き上げ、出口側端面を吸引することにより、空気などのガスを入口流路２１０、隔壁、及び、出口流路２２０内の順に供給し、余分なスラリーを多孔質基材から吸引して除去した。その後、多孔質基材を乾燥させ、ハニカム構造体を得た。触媒の担持量は、ハニカム構造体の単位体積あたり０．１１５ｇ／ｍ３とした。 A water slurry containing zeolite particles having an average particle size of 2.0 μm as a catalyst was prepared in a container. The porous substrate was submerged in the water slurry of the vessel. Thereafter, the porous substrate is pulled up from the water slurry, and the outlet side end face is sucked to supply a gas such as air in the order of the inlet channel 210, the partition walls, and the outlet channel 220, and the excess slurry is porous. The material was aspirated and removed. Thereafter, the porous substrate was dried to obtain a honeycomb structure. The catalyst loading was 0.115 g / m 3 per unit volume of the honeycomb structure.
　乾燥後のハニカム構造体の隔壁部２０１Ｗｉｏの垂直断面のＳＥＭ写真を図６に示す。黒い部分が空隙、白い部分が多孔質基材、グレーの部分が触媒である。入口流路側部分Ｒ１及び出口流路側部分Ｒ２の空隙率ε１、ε２はそれぞれ、３４．９％、及び、４３．４％であった。空隙率の計算においては、画像の横幅が概ね７００μｍぐらいになる倍率で撮影された画像を用い、隔壁部の全体の体積と、隔壁部において多孔質基材及び触媒に該当しない空間部の体積を求めることにより、空隙率を求めた。 FIG. 6 shows an SEM photograph of the vertical cross section of the partition wall 201Wio of the honeycomb structure after drying. A black part is a space | gap, a white part is a porous base material, and a gray part is a catalyst. The porosity ε 1 and ε 2 of the inlet channel side portion R1 and the outlet channel side portion R2 were 34.9% and 43.4%, respectively. In calculating the porosity, an image taken at a magnification of approximately 700 μm is used, and the total volume of the partition wall and the volume of the space that does not correspond to the porous substrate or catalyst in the partition wall are calculated. By determining the porosity, the porosity was determined.
　（比較例１）
　入口流路内に凸部及び凹部を設けず六角形状とする以外は実施例１と同様にし、平坦な隔壁部２０１Ｗｉｏにおける出口流路に主として触媒が保持されるようにした。触媒付与前のε１及びε２は両方とも５８％であった。触媒付与後のε１は３３．９％、ε２は４４．３％であった。 (Comparative Example 1)
The catalyst was mainly held in the outlet channel in the flat partition wall 201Wio in the same manner as in Example 1 except that the inlet channel had no hexagonal shape and no protrusions and recesses were provided. Both ε 1 and ε 2 before applying the catalyst were 58%. Ε 1 after application of the catalyst was 33.9%, and ε 2 was 44.3%.
　（初期圧力損失の測定）
　ガス流量２ｍ３／ｈ、４ｍ３／ｈ、および６ｍ３／ｈのそれぞれにおいて、ガス温度室温にて各フィルタに対してガスを供給し、煤のない状態における初期の圧力損失を測定した。また、実施例１及び比較例１の触媒塗布前の多孔質基材についても、それぞれ同様に圧力損失の変化の測定を行った。結果を図７に示す。表１には、ガス流量６ｍ３／ｈにおける触媒付与前及び触媒付与後の実施例１及び比較例１のフィルタの初期の圧力損失を示す。実施例１及び比較例１の初期圧力損失の差は、触媒塗布前よりも触媒塗布後の方が各段に大きくなった。
Figure JPOXMLDOC01-appb-T000001
 (Measurement of initial pressure loss)
At each gas flow rate of 2 m 3 / h, 4 m 3 / h, and 6 m 3 / h, gas was supplied to each filter at a gas temperature of room temperature, and the initial pressure loss in a state without soot was measured. Moreover, the change of the pressure loss was similarly measured about the porous base material before the catalyst application of Example 1 and Comparative Example 1, respectively. The results are shown in FIG. Table 1 shows the initial pressure loss of the filters of Example 1 and Comparative Example 1 before and after catalyst application at a gas flow rate of 6 m 3 / h. The difference in the initial pressure loss between Example 1 and Comparative Example 1 was greater at each stage after the catalyst application than before the catalyst application.
Figure JPOXMLDOC01-appb-T000001
　２００…ハニカムフィルタ、２０１ｉｎ…入口側端面（一端面）、２０１ｏｕｔ…出口側端面（他端面）、２０１Ｗｉｏ…入口流路２１０及び出口流路２２０を隔てる隔壁部、２０１…ハニカム構造体、２０１ｐ…封口部、２０１Ｗ…隔壁、２１０…入口流路（第１流路）、２１０ａ…凸部、２１０ｂ…凹部、２２０…出口流路（第２流路）、Ｒ１…入口流路側部分（第１流路側部分）、Ｒ２…出口流路側部分（第２流路側部分）。 DESCRIPTION OF SYMBOLS 200 ... Honeycomb filter, 201in ... Inlet side end surface (one end surface), 201out ... Outlet side end surface (other end surface), 201Wio ... Partition part which separates inlet channel 210 and outlet channel 220, 201 ... Honeycomb structure, 201p ... Sealing , 201W ... partition wall, 210 ... inlet channel (first channel), 210a ... convex portion, 210b ... concave portion, 220 ... outlet channel (second channel), R1 ... inlet channel side portion (first channel side) Part), R2... Outlet channel side part (second channel side part).

Claims (3)

  1. 　複数の第１流路及び複数の第２流路を有する、柱状のハニカム構造体を備え、
    　前記第１流路は、前記ハニカム構造体の一端面で開口されて他端面で閉じられ、
    　前記第２流路は、前記ハニカム構造体の前記一端面で閉じられて前記他端面で開口され、
    　前記第２流路は少なくとも１つの前記第１流路と隣り合い、
    　前記ハニカム構造体における前記第１流路と前記第２流路との間にある隔壁部は、前記第１流路の内面に凹凸を有し、
    　前記ハニカム構造体は、前記第２流路の表面から深さＤ（ただし、Ｄは前記隔壁部の最小厚みの半分）までの第２流路側部分と、前記第２流路側部分と前記複数の第１流路との間の第１流路側部分とを有し、前記第１流路側部分の空隙率（単位：％）をε１とし、前記第２流路側部分の空隙率（単位：％）をε２としたときに、ε１＜ε２を満たす、ハニカムフィルタ。     A columnar honeycomb structure having a plurality of first channels and a plurality of second channels,
    The first flow path is opened at one end face of the honeycomb structure and closed at the other end face,
    The second flow path is closed at the one end face of the honeycomb structure and opened at the other end face,
    The second flow path is adjacent to at least one of the first flow paths;
    The partition wall portion between the first channel and the second channel in the honeycomb structure has irregularities on the inner surface of the first channel,
    The honeycomb structure includes a second flow path side portion from the surface of the second flow path to a depth D (where D is half the minimum thickness of the partition wall), the second flow path side portion, and the plurality of the plurality of the honeycomb structures. and a first flow path side portion between the first flow path, the porosity (unit:%) of the first flow path side portion of the epsilon 1, the porosity of the second flow path side portion (unit:% ) a when a epsilon 2, satisfy ε 1 <ε 2, the honeycomb filter.
  2. 　１０≦ε２≦７０、かつ、１≦ε２－ε１≦６９を満たす、請求項１記載のハニカムフィルタ。 The honeycomb filter according to claim 1, wherein 10 ≦ ε 2 ≦ 70 and 1 ≦ ε 2 −ε 1 ≦ 69 are satisfied.
  3. 　前記ハニカム構造体は、細孔を有する多孔質基材と、前記細孔内に保持された、触媒、又は、触媒を担持した担体を含む、請求項１又は２に記載のハニカムフィルタ。 The honeycomb filter according to claim 1 or 2, wherein the honeycomb structure includes a porous base material having pores and a catalyst or a carrier supporting the catalyst held in the pores.
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JPWO2018037637A1 (en) * 2016-08-26 2019-08-29 エヌ・イーケムキャット株式会社 Honeycomb structure, honeycomb structure-type catalyst and manufacturing method
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