WO2021044874A1 - Filtre en nid d'abeilles et procédé pour fabriquer un filtre ne nid d'abeilles - Google Patents

Filtre en nid d'abeilles et procédé pour fabriquer un filtre ne nid d'abeilles Download PDF

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WO2021044874A1
WO2021044874A1 PCT/JP2020/031601 JP2020031601W WO2021044874A1 WO 2021044874 A1 WO2021044874 A1 WO 2021044874A1 JP 2020031601 W JP2020031601 W JP 2020031601W WO 2021044874 A1 WO2021044874 A1 WO 2021044874A1
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exhaust gas
honeycomb
honeycomb filter
particles
measured
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PCT/JP2020/031601
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English (en)
Japanese (ja)
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広和 五十嵐
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イビデン株式会社
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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
    • 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
    • B01J35/00—Catalysts, in general, characterised by their form or physical properties
    • B01J35/50—Catalysts, in general, characterised by their form or physical properties characterised by their shape or configuration
    • B01J35/56—Foraminous structures having flow-through passages or channels, e.g. grids or three-dimensional monoliths
    • 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
    • B01J35/00—Catalysts, in general, characterised by their form or physical properties
    • B01J35/60—Catalysts, in general, characterised by their form or physical properties characterised by their surface properties or porosity
    • 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
    • B01J37/00—Processes, in general, for preparing catalysts; Processes, in general, for activation of catalysts
    • B01J37/04—Mixing
    • 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
    • B01J37/00—Processes, in general, for preparing catalysts; Processes, in general, for activation of catalysts
    • B01J37/08—Heat treatment
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B28—WORKING CEMENT, CLAY, OR STONE
    • B28B—SHAPING CLAY OR OTHER CERAMIC COMPOSITIONS; SHAPING SLAG; SHAPING MIXTURES CONTAINING CEMENTITIOUS MATERIAL, e.g. PLASTER
    • B28B3/00—Producing shaped articles from the material by using presses; Presses specially adapted therefor
    • B28B3/20—Producing shaped articles from the material by using presses; Presses specially adapted therefor wherein the material is extruded
    • 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
    • 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
    • F01N3/08—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous
    • F01N3/10—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust
    • 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
    • F01N3/08—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous
    • F01N3/10—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust
    • F01N3/24—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust characterised by constructional aspects of converting apparatus
    • F01N3/28—Construction of catalytic reactors

Definitions

  • the present invention relates to a honeycomb filter and a method for manufacturing a honeycomb filter.
  • Exhaust gas emitted from an internal combustion engine of an automobile or the like contains harmful gases such as carbon monoxide (CO), nitrogen oxides (NOx), and hydrocarbons (HC), and particulate matter (PM).
  • An exhaust gas purification catalyst that decomposes such harmful gases is also called a three-way catalyst, and a catalyst layer is provided by wash-coating a slurry containing noble metal particles having catalytic activity on a honeycomb-shaped monolithic substrate made of cordierite or the like. Those are common and are used with a honeycomb filter for removing PM.
  • Patent Document 1 contains at least one co-catalyst selected from the group consisting of ceria, zirconia, and ceria-zirconia solid solution as a component of the cell wall as a filter for simultaneously removing the harmful gas and PM.
  • an exhaust gas filter in which pores communicating with adjacent cell holes are formed on the cell wall is disclosed.
  • the cell wall In order to remove PM in the exhaust gas filter, the cell wall is required to have pores having a size suitable for passing exhaust gas and collecting PM.
  • the pore size distribution of the cell wall is affected by the particle size distribution of the particles used as the raw material.
  • Patent Document 1 does not mention the particle size of the ceria-zirconia solid solution, alumina, and the pore-forming material which are the raw materials of the filter. Therefore, in Patent Document 1, there is room for improving the filter performance by changing the pore size distribution of the cell wall.
  • the present invention has been made to solve the above problems, and an object of the present invention is to provide a honeycomb filter having high filter performance. Another object of the present invention is to provide a method for manufacturing a honeycomb filter having high filter performance.
  • the honeycomb filter of the present invention has a porous cell partition that partitions a plurality of cells serving as an exhaust gas flow path, and an exhaust gas in which an end on the exhaust gas inlet side is opened and an end on the exhaust gas outlet side is sealed.
  • a honeycomb filter including an introduction cell and an exhaust gas discharge cell having an exhaust gas outlet side end open and an exhaust gas inlet side end sealed, wherein the honeycomb fired body is ceria.
  • the average particle size of the ceria-zirconia composite oxide particles including zirconia composite oxide particles and alumina particles is 5 ⁇ m or more and 30 ⁇ m or less, and the average particle size of the alumina particles is measured by SEM. Is 10 ⁇ m or more and 30 ⁇ m or less.
  • the average particle size measured by SEM of the ceria-zirconia composite oxide particles (hereinafter, also referred to as CZ particles) and alumina particles (hereinafter, collectively referred to as raw material particles) constituting the honeycomb fired body is in the above range.
  • the raw material composition for molding the honeycomb molded body to be the honeycomb filter gaps having pores having a size suitable for PM collection after firing are likely to be formed between the raw material particles.
  • pores having a cumulative 50% pore diameter D50 of 5 to 20 ⁇ m in the pore diameter distribution of macropores are likely to be formed.
  • the macropores refer to pores having a pore diameter of 0.1 ⁇ m to 100 ⁇ m measured by the mercury intrusion method. Therefore, the honeycomb filter has high filter performance.
  • the D50 in the pore size distribution of the macropores constituting the honeycomb fired body is preferably 5 to 20 ⁇ m.
  • D50 in the pore size distribution of macropores is 5 to 20 ⁇ m, it has many pores (pores) having a size suitable for collecting PM, so that the collection efficiency of PM is high and the pressure loss is low. can do.
  • D50 in the pore size distribution of macropores is a cumulative 50% pore size obtained from the pore size distribution curve of the honeycomb filter obtained in the range of 0.1 ⁇ m to 100 ⁇ m.
  • a porous cell partition wall that partitions a plurality of cells serving as an exhaust gas flow path, an end portion on the exhaust gas inlet side is opened, and an end portion on the exhaust gas outlet side is sealed.
  • a method for manufacturing a honeycomb filter which comprises a fired exhaust gas cell including an exhaust gas introduction cell and an exhaust gas discharge cell in which the end on the exhaust gas outlet side is opened and the end on the exhaust gas inlet side is sealed.
  • the d50 CZ to be produced is 5 ⁇ m or more and 30 ⁇ m or less
  • the d50 Al measured by laser diffraction of the alumina particles is 10 ⁇ m or more and 30 ⁇ m or less.
  • CZ particles having a d50 CZ of 5 ⁇ m or more and 30 ⁇ m measured by laser diffraction and alumina particles having a d50 Al of 10 ⁇ m or more and 30 ⁇ m or less measured by laser diffraction are used.
  • d50 measured by laser diffraction of CZ particles and alumina particles is in the above range, it is suitable for collecting PM after firing between the raw material particles in the raw material composition for molding the honeycomb molded body to be the honeycomb filter. Gap that becomes pores of a large size is likely to be formed. Therefore, a honeycomb filter having high filter performance can be manufactured.
  • the cumulative 10% particle diameter d10 CZ measured by laser diffraction of the ceria-zirconia composite oxide particles is 1.5 ⁇ m or more, and is measured by laser diffraction of the alumina particles.
  • the cumulative 10% particle diameter d10 Al is preferably 3 ⁇ m or more.
  • FIG. 1A is a perspective view schematically showing an example of the honeycomb filter of the present invention
  • FIG. 1B is a cross-sectional view taken along the line AA in FIG. 1A
  • FIG. 2 is an SEM photograph of the cut surface of the honeycomb filter produced in Example 1.
  • FIG. 3 is an SEM photograph of the cut surface of the honeycomb filter produced in Comparative Example 1.
  • the honeycomb filter of the present invention has a porous cell partition that partitions a plurality of cells serving as an exhaust gas flow path, and an exhaust gas in which the end on the exhaust gas inlet side is opened and the end on the exhaust gas outlet side is sealed. It is composed of a honeycomb fired body including an introduction cell and an exhaust gas discharge cell in which the end on the exhaust gas outlet side is opened and the end on the exhaust gas inlet side is sealed. In the honeycomb fired body, a plurality of cells are arranged side by side in the longitudinal direction of the honeycomb fired body with the cell partition wall interposed therebetween.
  • the honeycomb fired body contains ceria-zirconia composite oxide particles and alumina particles.
  • the honeycomb fired body is produced by extrusion-molding a raw material composition containing CZ particles, alumina particles, and an inorganic binder, and then firing the mixture. Whether or not the honeycomb filter of the present invention has the above-mentioned components can be confirmed by X-ray diffraction (XRD).
  • the honeycomb filter of the present invention may include a single honeycomb fired body, a plurality of honeycomb fired bodies, or a plurality of honeycomb fired bodies may be bonded by an adhesive. ..
  • an outer peripheral coat layer may be formed on the outer peripheral surface of the honeycomb fired body.
  • FIG. 1A is a perspective view schematically showing an example of the honeycomb filter of the present invention
  • FIG. 1B is a cross-sectional view taken along the line AA in FIG. 1A.
  • a porous cell partition wall 20 for partitioning a plurality of cells 12 and 13 serving as an exhaust gas flow path and an end portion 11a on the exhaust gas inlet side are opened and the exhaust gas outlet side.
  • It is composed of a single honeycomb fired body 11 including an exhaust gas discharge cell 13.
  • the exhaust gas introduction cell 12 and the exhaust gas discharge cell 13 are arranged along the longitudinal direction of the honeycomb fired body (direction indicated by the double-headed arrow a in FIG. 1A) with the cell partition wall 20 interposed therebetween.
  • the exhaust gas enters the exhaust gas introduction cell 12 that opens at the end portion 11a on the exhaust gas inlet side, passes through the cell partition wall 20, and then on the exhaust gas outlet side. It is discharged from the exhaust gas discharge cell 13 that opens to the end portion 11b.
  • the honeycomb filter 10 is composed of a single honeycomb fired body 11
  • the honeycomb fired body 11 is also the honeycomb filter itself.
  • the average particle size of CZ particles measured by SEM is 5 ⁇ m or more and 30 ⁇ m or less, and the average particle size of alumina particles measured by SEM is 10 ⁇ m or more and 30 ⁇ m or less.
  • the average particle size of the CZ particles and alumina particles constituting the honeycomb fired body is determined by taking an SEM photograph of the honeycomb fired body using a scanning electron microscope (SEM, for example, S-4800 manufactured by Hitachi High-Tech). be able to. First, a region of 200 ⁇ m ⁇ 500 ⁇ m was randomly selected from an image obtained by magnifying the cut surface of the cell partition wall obtained by cutting the honeycomb fired body 250 times with SEM (acceleration voltage: 15 kV), and all CZs existing in this region were selected. Count the number and area of particles and alumina particles. The projected area equivalent diameter (diameter) is calculated from the area of each particle, and the average value is taken as the average particle diameter. However, due to the resolution of SEM, particles with an area of 0.1 ⁇ m 2 or less are excluded from the measurement range. In SEM observation, the CZ particles and the alumina particles have different shades of color, so that they can be easily distinguished.
  • SEM scanning electron microscope
  • the porosity of the cell partition wall of the honeycomb fired body is 40 to 80% by volume.
  • the porosity of the cell partition wall of the honeycomb fired body is 40 to 80% by volume, both high mechanical strength and exhaust gas purification performance can be achieved at the same time.
  • the porosity of the cell partition wall of the honeycomb fired body can be measured by the mercury press-fitting method.
  • the porosity of the cell bulkhead of the honeycomb fired body is less than 40% by volume, the proportion of pores that can contribute to gas passage in the cell bulkhead is reduced, and the pressure loss may be improved.
  • the porosity of the cell partition wall of the honeycomb fired body exceeds 80% by volume, the porosity of the cell partition wall becomes too high, so that the mechanical properties of the honeycomb filter deteriorate and cracks occur during use of the honeycomb filter. Destruction is likely to occur.
  • the fired honeycomb body contains macropores having a pore diameter of 0.1 to 100 ⁇ m.
  • the ratio of the volume occupied by the macropores is preferably 80% by volume or more of the total volume of the pores.
  • the ratio of the volume occupied by the macropores and the total volume of the pores can be obtained by measuring the pore diameter of the cell partition wall of the fired honeycomb body by the mercury press-fitting method.
  • the D50 in the pore size distribution of the macropores constituting the honeycomb fired body is preferably 5 to 20 ⁇ m.
  • D50 in the pore size distribution of macropores is 5 to 20 ⁇ m, it has many pores (pores) having a size suitable for collecting PM, so that the collection efficiency of PM is high and the pressure loss is low. can do.
  • D50 in the pore size distribution of the macropores constituting the honeycomb fired body is the pore size distribution curve measured by the mercury intrusion method [horizontal axis: pore diameter ( ⁇ m), vertical axis: log differential pore volume (mL / g). ] Can be obtained from.
  • a honeycomb fired body is cut into cubes having a side of about 0.8 cm, ultrasonically washed with ion-exchanged water, sufficiently dried, and used as a measurement sample.
  • the pore size is measured by the mercury press-fitting method (according to JISR1655: 2003).
  • the pore size of the obtained sample is measured using a Micromeritix automatic porosimeter Autopore III9405 manufactured by Shimadzu Corporation.
  • the measurement range is 0.006 to 500 ⁇ m.
  • the measurement is performed at every 0.1 psia pressure, and at 0.006 to 100 ⁇ m, the measurement is performed at every 0.25 psia pressure.
  • the D50 of the macropore is calculated with the pore diameter as the macropore.
  • the contact angle is 130 ° and the surface tension is 485 mN / m.
  • the alumina particles constituting the honeycomb filter of the present invention are preferably ⁇ -phase alumina particles. Since the alumina particles are ⁇ -phase alumina particles, they have high heat resistance, so that they can support a noble metal and exhibit high exhaust gas purification performance even after long-term use.
  • the content ratio of alumina particles is preferably 15 to 35% by weight. Further, in the honeycomb filter of the present invention, the content ratio of CZ particles is preferably 35 to 65% by weight.
  • the honeycomb filter of the present invention further contains an alumina fiber. This is because the mechanical properties of the honeycomb filter can be improved by including the alumina fiber.
  • the binder content is preferably 0.1 to 10% by weight, and the alumina fiber content is preferably 10 to 40% by weight.
  • the shape of the honeycomb filter of the present invention is not limited to a columnar shape, and examples thereof include a prismatic column, an elliptical columnar shape, an oblong columnar shape, and a round chamfered prismatic shape (for example, a round chamfered triangular columnar shape).
  • the shape of the cells of the honeycomb fired body is not limited to the square columnar shape, and examples thereof include a triangular columnar column and a hexagonal columnar column.
  • the density of cells having a cross section perpendicular to the longitudinal direction of the honeycomb fired body is 31 to 155 cells / cm 2.
  • the thickness of the cell partition wall of the honeycomb fired body is preferably 0.05 to 0.50 mm, and more preferably 0.10 to 0.30 mm.
  • the thickness of the outer peripheral coat layer is preferably 0.1 to 2.0 mm.
  • honeycomb filter of the present invention it is desirable that a precious metal is supported on the fired honeycomb body.
  • a noble metal that functions as a catalyst is supported on the honeycomb fired body, it can also be used as a honeycomb catalyst for exhaust gas purification.
  • the noble metal include platinum, palladium, rhodium and the like.
  • the amount of the noble metal supported is preferably 0.1 to 15 g / L, and more preferably 0.5 to 10 g / L.
  • the amount of noble metal supported refers to the weight of the noble metal per apparent volume of the honeycomb filter.
  • the apparent volume of the honeycomb filter is a volume including the volume of the voids, and includes the volume of the outer peripheral coat layer and / or the adhesive layer.
  • a porous cell partition wall forming a plurality of cells serving as an exhaust gas flow path and an end portion on the exhaust gas inlet side are opened and an end portion on the exhaust gas outlet side is sealed.
  • a method for manufacturing a honeycomb filter comprising a fired exhaust gas cell including an exhaust gas introduction cell and an exhaust gas discharge cell having an exhaust gas outlet side end opened and an exhaust gas inlet side end sealed.
  • a raw material composition preparation step for preparing a raw material composition containing zirconia composite oxide particles and alumina particles and molding the above raw material composition, a plurality of cells are arranged side by side in the longitudinal direction across the cell partition wall.
  • Measured by laser diffraction of the ceria-zirconia composite oxide particles contained in the raw material composition including a molding step of producing a honeycomb molded body and a firing step of firing the honeycomb molded body to obtain a honeycomb fired body.
  • the d50 CZ to be produced is 5 ⁇ m or more and 30 ⁇ m or less
  • the d50 Al measured by laser diffraction of the alumina particles is 10 ⁇ m or more and 30 ⁇ m or less.
  • the ceria-zirconia composite oxide particles and alumina particles are mixed to prepare a raw material composition.
  • the d50 CZ measured by laser diffraction of the CZ particles used when preparing the raw material composition is 5 ⁇ m or more and 30 ⁇ m or less
  • the d50 Al measured by laser diffraction of the alumina particles is 10 ⁇ m or more and 30 ⁇ m or less.
  • the cumulative 10% particle diameter d10 CZ measured by laser diffraction of CZ particles is preferably 1.5 ⁇ m or more.
  • the cumulative 10% particle diameter d10 Al measured by laser diffraction of the alumina particles is preferably 3 ⁇ m or more.
  • a laser diffraction type particle size distribution measuring device (for example, MASTERSIER2000 manufactured by MALVERN) is used for measuring d50 and d10 of the alumina particles and CZ particles which are the raw material particles. Specifically, in the cumulative volume distribution curve of the particles obtained by the above measuring device, the particle diameters corresponding to the cumulative volume of 50% by volume from the smallest particle diameter are d50 CZ and d50 Al . Further, the particle diameters corresponding to the cumulative volume of 10% by volume from the smaller particle diameter are the cumulative 10% particle diameters d10 CZ and d10 Al .
  • the weight ratio of the ceria-zirconia composite oxide particles (ceria-zirconia composite oxide particles / alumina particles) to the alumina particles used when preparing the raw material composition shall be 1.0 to 3.0. Is desirable.
  • the weight ratio (ceria-zirconia composite oxide particles / alumina particles) is 1.0 to 3.0, the content of the ceria-zirconia composite oxide particles is high, and the ceria-zirconia composite oxide particles are: Since it is used as a co-catalyst, the purification performance of exhaust gas is improved.
  • ⁇ -phase alumina particles are desirable.
  • a pore-forming material may be added to the raw material composition.
  • pore-forming material examples include acrylic resin, starch, carbon and the like, and among these, it is desirable to use acrylic resin.
  • raw materials used in preparing the raw material composition include inorganic fibers, inorganic binders, organic binders, molding aids, dispersion media and the like.
  • the material constituting the inorganic fiber is not particularly limited, and examples thereof include alumina, silica, silicon carbide, silica alumina, glass, potassium titanate, aluminum borate, and the like, and two or more of them may be used in combination. Of these, alumina fiber is desirable.
  • the aspect ratio of the inorganic fiber is preferably 5 to 300, more preferably 10 to 200, and even more preferably 10 to 100.
  • the inorganic binder is not particularly limited, and examples thereof include solids contained in alumina sol, silica sol, titania sol, water glass, sepiolite, attapulsite, boehmite, and the like, and two or more of these inorganic binders may be used in combination. Of these, boehmite is desirable.
  • Boehmite is an alumina monohydrate represented by the composition of AlOOH and disperses well in a medium such as water. Therefore, it is desirable to use boehmite as a binder in the method for producing a honeycomb filter of the present invention.
  • the organic binder is not particularly limited, and examples thereof include methyl cellulose, carboxymethyl cellulose, hydroxyethyl cellulose, polyethylene glycol, phenol resin, epoxy resin, and the like, and two or more kinds may be used in combination.
  • the dispersion medium is not particularly limited, and examples thereof include water, an organic solvent such as benzene, an alcohol such as methanol, and two or more thereof may be used in combination.
  • the molding aid is not particularly limited, and examples thereof include ethylene glycol, dextrin, fatty acid, fatty acid soap, and polyalcohol, and two or more of them may be used in combination.
  • CZ particles, alumina particles, alumina fibers and boehmite were used as the above-mentioned raw materials, the blending ratio of these was CZ particles: 40 to 60% by weight, alumina particles, based on the total solid content remaining after the firing step in the raw materials. : 15 to 35% by weight, alumina fiber: 10 to 40% by weight, boehmite: 0.1 to 10% by weight is desirable.
  • the mixture When preparing the raw material composition, it is desirable to mix and knead, and the mixture may be mixed using a mixer, an attritor or the like, or may be kneaded using a kneader or the like.
  • a honeycomb molded body in which a plurality of cells are arranged side by side in the longitudinal direction with the cell partition wall interposed therebetween is produced. Specifically, a continuous body of a honeycomb molded body having cells having a predetermined shape is formed by passing through a mold having a predetermined shape, and the honeycomb molded body is formed by cutting into a predetermined length.
  • the honeycomb molded body can be dried to produce a honeycomb dried body using a dryer such as a microwave dryer, a hot air dryer, a dielectric dryer, a vacuum dryer, a vacuum dryer, or a freeze dryer. desirable.
  • a dryer such as a microwave dryer, a hot air dryer, a dielectric dryer, a vacuum dryer, a vacuum dryer, or a freeze dryer.
  • honeycomb molded body and the honeycomb dried body before the firing step are collectively referred to as a honeycomb molded body.
  • a predetermined amount of a sealing material paste is filled in any end of the cell constituting the dried body of the honeycomb molded product, and the cell is sealed.
  • a mask for cell sealing is applied to the end surface of the honeycomb molded body (that is, the cut surface after cutting both ends), and the sealing material is applied only to the cells that need to be sealed. Fill the paste and allow the encapsulant paste to dry. Through such a process, a dried honeycomb body in which one end of the cell is sealed is produced.
  • the encapsulant paste the above raw material composition can be used.
  • the step of sealing the cells with the sealing material paste may be performed after the firing step described later, or may be re-baked after the sealing step.
  • a honeycomb fired body is produced by firing the molded body dried in the drying step. Since this step is degreasing and firing of the honeycomb molded body, it can be referred to as a “degreasing / firing step”, but for convenience, it is referred to as a "baking step”.
  • the temperature of the firing step is preferably 800 to 1300 ° C, more preferably 900 to 1200 ° C.
  • the firing step time is preferably 1 to 24 hours, more preferably 3 to 18 hours.
  • the atmosphere of the firing step is not particularly limited, but it is desirable that the oxygen concentration is 1 to 20%.
  • the honeycomb filter of the present invention can be manufactured.
  • the method for producing a honeycomb filter of the present invention may further include a supporting step of supporting the noble metal on the fired honeycomb body, if necessary.
  • Examples of the method of supporting the precious metal on the honeycomb fired body include a method of immersing the honeycomb fired body or the honeycomb filter in a solution containing noble metal particles or a complex, and then pulling up and heating the honeycomb filter.
  • the honeycomb filter includes the outer peripheral coat layer
  • the noble metal may be supported on the honeycomb fired body before the outer peripheral coat layer is formed, or the noble metal may be supported on the honeycomb fired body or the honeycomb filter after the outer peripheral coat layer is formed. You may.
  • the amount of the noble metal supported in the supporting step is preferably 0.1 to 15 g / L, and more preferably 0.5 to 10 g / L.
  • the outer peripheral coat layer is formed on the outer peripheral surface of the fired honeycomb body, the outer peripheral coat layer is formed after the outer peripheral coat layer paste is applied to the outer peripheral surface excluding both end faces of the fired honeycomb body.
  • the paste for the outer peripheral coat layer include those having the same composition as the raw material composition.
  • Example 1 16.7% by weight of CZ particles (d50 CZ : 8.0 ⁇ m, d10 CZ : 1.8 ⁇ m), 8.4% by weight of alumina particles (d50 CZ : 20 ⁇ m, d10 Al: 4.4 ⁇ m), boehmite as an inorganic binder 2.8% by weight, 10.4% by weight of alumina fiber having an average fiber diameter of 3 ⁇ m and 100 ⁇ m of average fiber length, 3.9% by weight of methylcellulose as an organic binder, and acrylic resin (d50: 32 ⁇ m) as a pore-forming material.
  • CZ particles d50 CZ : 8.0 ⁇ m, d10 CZ : 1.8 ⁇ m
  • alumina particles d50 CZ : 20 ⁇ m, d10 Al: 4.4 ⁇ m
  • boehmite as an inorganic binder 2.8% by weight
  • the cumulative 50% particle size (d50 CZ and d50 Al ) of the alumina particles and CZ particles, the cumulative 10% particle size (d10 CZ and d10 Al ), and the d50 of the pore-forming material are the laser diffraction type particle size distribution measuring device (MALVERN). It was measured using MASTERSIZER2000) manufactured by the company.
  • the raw material composition was extruded using an extrusion molding machine to prepare a columnar honeycomb molded body. Then, the honeycomb molded body is dried at an output of 1.74 kW and a reduced pressure of 6.7 kPa for 12 minutes using a vacuum microwave dryer, and then a sealing material is applied to one end of the cells constituting the honeycomb molded body.
  • a sealing material paste having the same composition as the raw material composition used to prepare the honeycomb molded body is filled in a predetermined cell of the honeycomb molded body so that the paste is filled, and further at 120 ° C. under atmospheric pressure. It was dried for 10 minutes. Then, by degreasing and firing at 1150 ° C.
  • honeycomb fired body honeycomb filter
  • the honeycomb fired body had a columnar shape having a diameter of 118 mm and a length of 122 mm, a cell density of 46.5 cells / cm 2 (300 cpsi), and a cell partition wall thickness of 0.203 mm (8 mil).
  • Example 2 The honeycomb structure according to Example 2 was produced in the same procedure as in Example 1 except that the particle diameters of CZ and alumina in the raw material composition were changed as shown in Table 1, respectively.
  • Comparative Example 1 The honeycomb structure according to Comparative Example 1 was produced in the same procedure as in Example 1 except that the particle diameters of CZ and alumina in the raw material composition were changed as shown in Table 1, respectively.
  • FIG. 2 is an SEM photograph of the cut surface of the honeycomb filter produced in Example 1
  • FIG. 3 is an SEM photograph of the cut surface of the honeycomb filter produced in Comparative Example 1.
  • the average particle size of the CZ particles in the honeycomb filter produced in Example 1 was 5.3 ⁇ m.
  • the average particle size of the alumina particles in the honeycomb filter produced in Example 1 was 12.2 ⁇ m.
  • the average particle size of the CZ particles in the honeycomb filter produced in Comparative Example 1 was 1.2 ⁇ m, respectively.
  • the average particle size of the alumina particles in the honeycomb filter produced in Comparative Example 1 was 1.4 ⁇ m, respectively. From this result, the particle diameters of the CZ particles and alumina particles used as raw materials (average particle diameter measured by laser diffraction) and the particle diameters of the CZ particles and alumina particles constituting the honeycomb fired body (average particles measured by SEM). It was confirmed that the diameter) corresponds.
  • the pore size distribution of the cell partition wall was measured by the mercury intrusion method to obtain D50.
  • the D50 of the honeycomb filter produced in Example 1 was 9.4 ⁇ m.
  • the D50 of the honeycomb filter produced in Example 2 was 15.8 ⁇ m, and the D50 of the honeycomb filter produced in Comparative Example was 1.8 ⁇ m. From this result, it can be seen that D50 is in the range of the preferable pore diameter of 5 to 20 ⁇ m, and the pore diameter distribution of the honeycomb filter produced in the example is suitable for PM collection.
  • the honeycomb structure of the present invention can reduce the pressure loss and has a macropore D50 of 5 to 20 ⁇ m, which is suitable for collecting PM. Therefore, one end of the cell is used. It can be seen that excellent filter performance is exhibited when the portion is sealed and used as a filter for removing PM.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • Materials Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Organic Chemistry (AREA)
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  • Toxicology (AREA)
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  • Ceramic Engineering (AREA)
  • Biomedical Technology (AREA)
  • Environmental & Geological Engineering (AREA)
  • Manufacturing & Machinery (AREA)
  • Thermal Sciences (AREA)
  • Oil, Petroleum & Natural Gas (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Geology (AREA)
  • Filtering Materials (AREA)
  • Exhaust Gas After Treatment (AREA)
  • Processes For Solid Components From Exhaust (AREA)
  • Press-Shaping Or Shaping Using Conveyers (AREA)
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Abstract

La présente invention concerne un filtre en nid d'abeilles comprenant un corps cuit en nid d'abeilles comprenant : des parois de séparation de cellules poreuses qui forment, par segmentation, une pluralité de cellules servant de passages d'écoulement pour le gaz d'échappement ; des cellules d'introduction de gaz d'échappement ayant chacune une partie d'extrémité sur le côté d'entrée de gaz d'échappement ouvert et une partie d'extrémité sur le côté de sortie de gaz d'échappement bouché ; et des cellules de décharge de gaz d'échappement ayant chacune une partie d'extrémité sur le côté de sortie de gaz d'échappement ouvert et une partie d'extrémité sur le côté d'entrée de gaz d'échappement bouché. Le filtre en nid d'abeilles est caractérisé en ce que le corps cuit en nid d'abeilles contient des particules d'oxyde composite d'oxyde de cérium-zircone et des particules d'alumine, le diamètre de particule moyen des particules d'oxyde composite d'oxyde de cérium-zircone mesurées par un SEM est de 5 à 30 µm, et le diamètre de particule moyen des particules d'alumine mesurées par le SEM est de 10 à 30 µm.
PCT/JP2020/031601 2019-09-04 2020-08-21 Filtre en nid d'abeilles et procédé pour fabriquer un filtre ne nid d'abeilles WO2021044874A1 (fr)

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Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH01194916A (ja) * 1988-01-27 1989-08-04 Ibiden Co Ltd 炭化ケイ素質ハニカム状フィルターの製造方法
JPH1129360A (ja) * 1997-07-10 1999-02-02 Matsushita Electric Ind Co Ltd セラミック可塑性練り土の製造方法及びセラミック可塑性練り土ならびにそれを用いた排ガスフィルタ
JP2011506237A (ja) * 2007-11-30 2011-03-03 コーニング インコーポレイテッド ゼオライト系ハニカム体
JP2017115786A (ja) * 2015-12-25 2017-06-29 株式会社デンソー 排ガスフィルタ
WO2018164069A1 (fr) * 2017-03-06 2018-09-13 イビデン 株式会社 Filtre en nid d'abeilles

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH01194916A (ja) * 1988-01-27 1989-08-04 Ibiden Co Ltd 炭化ケイ素質ハニカム状フィルターの製造方法
JPH1129360A (ja) * 1997-07-10 1999-02-02 Matsushita Electric Ind Co Ltd セラミック可塑性練り土の製造方法及びセラミック可塑性練り土ならびにそれを用いた排ガスフィルタ
JP2011506237A (ja) * 2007-11-30 2011-03-03 コーニング インコーポレイテッド ゼオライト系ハニカム体
JP2017115786A (ja) * 2015-12-25 2017-06-29 株式会社デンソー 排ガスフィルタ
WO2018164069A1 (fr) * 2017-03-06 2018-09-13 イビデン 株式会社 Filtre en nid d'abeilles

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