WO2006131995A1 - Diesel particulate filter and purifier making use of the same - Google Patents

Diesel particulate filter and purifier making use of the same Download PDF

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Publication number
WO2006131995A1
WO2006131995A1 PCT/JP2005/014739 JP2005014739W WO2006131995A1 WO 2006131995 A1 WO2006131995 A1 WO 2006131995A1 JP 2005014739 W JP2005014739 W JP 2005014739W WO 2006131995 A1 WO2006131995 A1 WO 2006131995A1
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WO
WIPO (PCT)
Prior art keywords
particulate filter
diesel particulate
heat
nonwoven fabric
oxide catalyst
Prior art date
Application number
PCT/JP2005/014739
Other languages
French (fr)
Japanese (ja)
Inventor
Masahiko Matsumoto
Original Assignee
Tosco Co., Ltd.
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Filing date
Publication date
Application filed by Tosco Co., Ltd. filed Critical Tosco Co., Ltd.
Publication of WO2006131995A1 publication Critical patent/WO2006131995A1/en

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    • 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
    • B01J35/58—Fabrics or filaments
    • 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
    • B01D39/2068—Other inorganic materials, e.g. ceramics
    • B01D39/2082—Other inorganic materials, e.g. ceramics the material being filamentary or fibrous
    • 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
    • B01D53/944—Simultaneously removing carbon monoxide, hydrocarbons or carbon making use of oxidation catalysts
    • 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
    • B01J23/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00
    • B01J23/002—Mixed oxides other than spinels, e.g. perovskite
    • 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
    • B01J23/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00
    • B01J23/16—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of arsenic, antimony, bismuth, vanadium, niobium, tantalum, polonium, chromium, molybdenum, tungsten, manganese, technetium or rhenium
    • B01J23/32—Manganese, technetium or rhenium
    • B01J23/34—Manganese
    • 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
    • B01J23/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00
    • B01J23/70—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of the iron group metals or copper
    • B01J23/76—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of the iron group metals or copper combined with metals, oxides or hydroxides provided for in groups B01J23/02 - B01J23/36
    • B01J23/83—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of the iron group metals or copper combined with metals, oxides or hydroxides provided for in groups B01J23/02 - B01J23/36 with rare earths or actinides
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2239/00—Aspects relating to filtering material for liquid or gaseous fluids
    • B01D2239/02—Types of fibres, filaments or particles, self-supporting or supported materials
    • B01D2239/0241—Types of fibres, filaments or particles, self-supporting or supported materials comprising electrically conductive fibres or particles
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2255/00—Catalysts
    • B01D2255/40—Mixed oxides
    • B01D2255/402—Perovskites
    • 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
    • B01J2523/00—Constitutive chemical elements of heterogeneous catalysts

Definitions

  • the present invention relates to a diesel particulate filter that enables simultaneous and complete removal of particulate matter (PM) and nitrogen oxides (NOx) contained in exhaust gas discharged from a diesel engine car. And a purification apparatus using the same.
  • Diesel engines are widely used mainly in trucks in Japan because of their excellent fuel economy and durability. Especially in Europe, excellent fuel economy and global warming gas CO emissions
  • PM particulate matter
  • NOx nitrogen oxides
  • a method for removing these particulate matter (PM) and nitrogen oxide (NOx) a method of providing a diesel particulate filter (DPF) on the exhaust gas side of a diesel engine is known.
  • DPF diesel particulate filter
  • a filter that has been used for a long time a filter using a nonwoven fabric of silicon carbide-based inorganic fibers can be cited. This filter collects PM contained in exhaust gas with a non-woven fabric and heats it to a high temperature (approximately 600 ° C) to convert the components of PM, carbon (C) and hydrocarbons (HC), into CO.
  • a diesel particulate filter carrying a perovskite-type compound having a nitrogen oxide NOx reducing action on the surface of fibers contained in such a nonwoven fabric (See Patent Document 2).
  • Patent Document 2 where the powerful perovskite type compound lacks the ability to remove PM, PM is removed by heating and heat treatment in an oxidizing atmosphere, regardless of the catalyst.
  • a so-called ceramic method is used in which component oxides and carbonates are mixed and fired.
  • the perovskite type spinel type composite oxidation catalyst manufactured by the alkoxide method or the simple nitrate dipping method has a small specific surface area (about 0.5m 2 Zg), and the exhaust gas and the catalyst have sufficient contact. Not done. Further, this composite oxidation catalyst is supported so as to cover a support such as a non-woven fabric and does not have a particle structure. Therefore, in such a diesel particulate filter, PM (carbon) is converted to CO and NOx is completely converted to nitrogen.
  • Patent Document 1 Japanese Patent Laid-Open No. 7-11933
  • Patent Document 2 JP 2002-301320 A
  • Patent Document 3 Japanese Patent Laid-Open No. 2003-239722
  • the first object of the present invention is to sufficiently remove particulate matter (PM), especially NO, which causes air pollution and dust pollution that are emitted from diesel engine exhaust gas power.
  • PM particulate matter
  • SPM small suspended particulate matter
  • NOx nitrogen oxides
  • a second object of the present invention is to provide a diesel particulate filter comprising a nonwoven fabric made of heat resistant fibers and a particulate composite oxide catalyst supported on the surface of the heat resistant fibers.
  • the third object of the present invention is to capture and remove particulate matter (PM), particularly suspended particulate matter (SPM) having a small particle diameter, on the surface of the nonwoven fabric, and to remove nitrogenous acid.
  • the object is to provide a compact and high-performance diesel particulate filter and a purification device for diesel engine exhaust gas, which can reduce and remove substances (NOx) at the same time, detoxify diesel engine exhaust gas with high efficiency.
  • a fourth object of the present invention is to provide a method for producing a diesel particulate filter comprising a non-woven fabric made of heat-resistant fibers and a composite oxide catalyst supported on the surface of the heat-resistant fibers.
  • the present inventors have supported the surface of a non-woven fabric made of a specific heat-resistant fiber with particles of a mouth-bushite complex oxide catalyst having a specific particle size. It was found that the diesel particulate filter showed good simultaneous removal performance of particulate matter (PM) and nitrogen oxides (NOx).
  • PM particulate matter
  • NOx nitrogen oxides
  • a diesel particulate filter comprising a nonwoven fabric composed of heat-resistant fibers and a perovskite-type composite oxide catalyst supported on the surface of the heat-resistant fibers, wherein the composite oxide catalyst is 0.1 to : It relates to a diesel particulate filter characterized by being particles having an average particle size of LOOnm.
  • the above-mentioned mouthbskite-type composite oxide catalyst has the formula (I):
  • A, B and C may be the same or different from each other.
  • the diesel particulate filter according to 1 above represented by:
  • the perovskite-type composite oxide catalyst is La K CoO, La Sr CoO or La
  • the nonwoven fabric thickness 0.1. 3 to: L0mm, and the force of density 0. 05 ⁇ : having L OgZcm 3, relates to a diesel particulate filter according to any force 1 above 1-4.
  • the present invention relates to a purifier for exhaust gas discharged.
  • a non-woven fabric comprising heat-resistant conductive fibers and particles of a perovskite-type composite oxide catalyst having an average particle diameter of 0.1 to 1 OOnm supported on the surface of the heat-resistant conductive fibers.
  • a diesel particulate filter manufacturing method comprising:
  • the diesel particulate filter of the present invention comprises a nonwoven fabric composed of heat-resistant fibers, And a mouth bumskite complex oxide catalyst supported on the surface of the heat resistant fiber.
  • a nonwoven fabric composed of heat-resistant fibers
  • a mouth bumskite complex oxide catalyst supported on the surface of the heat resistant fiber.
  • the nonwoven fabric of the present invention also has heat resistant fiber strength.
  • the heat-resistant fiber of the present invention is a fiber having a heat resistance of 800 ° C or higher, preferably 1000 ° C or higher.
  • the heat-resistant fiber of the present invention is preferably a heat-resistant conductive fiber in order to adhere the velovskite complex oxide catalyst particles by electrophoresis.
  • the heat-resistant conductive fiber of the present invention preferably has an electric resistance of, for example, 1.4 ⁇ ′cm or less, preferably 0.1 ⁇ ′cm or less.
  • the heat resistant fiber of the present invention is alkali resistant in order to support an alkali metal oxide containing K or the like.
  • the degree of alkali resistance is appropriately determined by measuring the tensile strength of a fiber that has been immersed in a 2.0% NaCl aqueous solution and then heat-treated in air at 1000 ° C. for 2 hours to reduce the strength. .
  • the heat-resistant fiber of the present invention is suitably an inorganic or organic fiber.
  • the inorganic fibers include silicon fibers mainly composed of silicon, silicon carbide fibers, and alumina fibers. More preferably, the silicon carbide fiber may contain components such as Ti, Zr and / or A1 in order to improve alkali resistance. These components are suitably contained in an amount of 0.1 to 2% by mass based on the entire fiber.
  • Such fibers include silicon carbide fibers, two-calon fibers (Si—O—C composition ratio 57.2: 32.7: 10, manufactured by Nippon Carbon Co., Ltd.), Tyranno Fiber (registered trademark) heat-resistant Darade ZM ( Si—C—O—Zr composition ratio 56: 34: 9: 1), Tyranno Fiber (registered trademark) heat-resistant grade S (Si-OC-Ti composition ratio 50: 30: 18: 2) Tyranno fiber (registered trademark) heat resistant Grade SA (Si-OC-Al composition ratio 67: 31: 1: 2) (Tyranno fiber (registered trademark) is all manufactured by Ube Industries, Ltd.) is preferable.
  • organic fiber carbon fiber is mentioned, for example.
  • the heat-resistant fiber of the present invention may be a combination of two or more of these fibers.
  • the average diameter of the heat-resistant fiber of the present invention is, for example, 3 to 20 ⁇ m, preferably 9 to 14 ⁇ m. If the diameter is 3 ⁇ m or more, it is preferable because the fibers themselves scatter and do not release gas-generating substances into the atmosphere.
  • the fiber length of the heat-resistant fiber of the present invention is, for example, 10 to: LOOmm, preferably 3
  • the tensile strength of the heat resistant fiber of the present invention is, for example, 1 to 5 GPa, preferably 2 to 4 GPa as measured by JIS K-7023.
  • the nonwoven fabric of the present invention is obtained by converting the above heat-resistant fiber into a nonwoven fabric by a known method, for example, a spunbond method, or JP-A 2000-199160 "Method and apparatus for producing inorganic short fiber felt". It can be.
  • the thickness of the nonwoven fabric of the present invention is, for example, 0.3 to LOmm, preferably 0.5 to 5 mm, more preferably 1 to 3 mm.
  • the basis weight of the nonwoven fabric of the present invention is, for example, 50 to: LOOOgZm 2 , preferably 100 to 500 g, more preferably 150 to 400 gZm 2 .
  • the strength density of the nonwoven fabric of the present invention is, for example, 0.05-: L Og / cm 3 , preferably 0.1-0.8 gZcm 3 , more preferably 0.2-0.6 gZcm 3 . Is appropriate. If the force density is 0.2 gZcm 3 or more, the PM collection performance can be sufficiently maintained, and if it is 1. OgZcm 3 or less, the exhaust gas using the diesel particulate filter of the present invention is used. This is preferable because the exhaust gas pressure of the water purification apparatus can be kept low.
  • the perovskite complex oxide is represented by a basic composition ABO,
  • A contains a metal ion having a large ion radius, such as a rare earth metal or an alkaline earth metal
  • B contains a transition metal ion.
  • the perovskite complex oxide catalyst of the present invention contains at least two elements selected from K, Ni, Sr, Co, La, Cu, V, Mn, Fe, Cs, Ba, Ce, Li and Pd.
  • the velovskite complex oxide catalyst of the present invention has the following formula (I):
  • A, B and C may be the same or different from each other.
  • a preferred perovskite type complex oxide catalyst of the present invention contains at least two elements selected from La, K, Co, Sr and Mn.
  • A is La
  • B is selected from K
  • Sr Li or Cs
  • C is selected from Co or Mn
  • Q 0. 1 to 0.3
  • p + q 1, and r is 1.
  • More preferred perovskite complex oxide catalysts of the present invention are La K CoO, La Sr
  • the perovskite complex oxide catalyst of the present invention is a particle having an average particle diameter of 0.1 to: L00 nm, preferably 0.5 to 50 nm, more preferably 1 to 20 nm.
  • L00 nm average particle diameter of 0.1 to: L00 nm, preferably 0.5 to 50 nm, more preferably 1 to 20 nm.
  • catalyst particles of about m When using catalyst particles of about m, it is necessary to sinter at 1000 ° C for 2 hours, but when using a catalyst with a small particle size as in the present invention, 400-800 If it is sintered at about ° C for 2 hours, it can be supported with sufficient strength.
  • the heat-resistant fiber surface can be completely and uniformly coated with a small amount of support.
  • the contact between the catalyst and the heat-resistant fiber surface can be kept stronger.
  • the specific surface area of the perovskite-type composite oxide catalyst of the present invention measured by the BET method is 10 m 2 m 2 / g or more, more preferably 30 m 2 / g or more, and still more preferably 50 m 2 / g. As described above, for example, 50-: L00m 2 / g is appropriate.
  • the perovskite type composite of the present invention The specific surface area of the acid oxide catalyst is measured by the BET method according to JIS R1626.
  • the diesel particulate filter of the present invention comprises a nonwoven fabric composed of the above-mentioned heat-resistant fiber, preferably a heat-resistant conductive fiber, and particles of the above-mentioned belobskite complex oxide catalyst supported on the fiber surface of this nonwoven fabric. .
  • the particles of the velovskite type complex oxide catalyst are contained in an amount of, for example, 0.120% by mass, preferably 0.55% by mass, with respect to the mass of the nonwoven fabric made of heat-resistant fibers.
  • the particles of the perovskite complex oxide catalyst are uniformly supported on the surface of the heat-resistant fiber of the nonwoven fabric without gaps. It is preferable that the surface of the non-woven heat-resistant fiber is substantially coated with particles of the perovskite complex oxide catalyst.
  • the layer of the particles of the open-bumskite complex oxide catalyst supported on the heat-resistant fiber surface is at least one layer, more preferably two or more layers.
  • the particle size of the particles of the velovskite complex oxide catalyst of the present invention supported on the heat-resistant fiber surface is the same as that before the support, for example, 0.1 to: LOOnm, preferably 0.5 50 nm More preferably, l is 20 nm.
  • the layer thickness of the particles of the perovskite complex oxide catalyst of the present invention is, for example, 0.1 1 00, preferably 50 nm, more preferably 20 50 nm.
  • the diesel particulate filter of the present invention is produced by preparing a perovskite-type composite oxide catalyst having a specific particle size, and supporting this bottom-bskite-type composite oxide catalyst on the surface of a heat resistant fiber of a nonwoven fabric. Is done.
  • the velovskite type complex oxide catalyst of the present invention may be produced by any known method, but is suitably produced by the ethylene glycol method shown below. Specifically, first, K ⁇ Ni ⁇ Sr ⁇ Co, La ⁇ Cu ⁇ V, Mn, Fe ⁇ Cs ⁇ Ba ⁇ Ce ⁇ Li ⁇ Pd and other formulas (I): Salts of elements constituting A, B and C of ABCO, preferably Nitrates,
  • P qr 3 Prepare sulfate or hydrochloride.
  • the salt is weighed and dissolved in a solvent such as alkylene glycol, such as ethylene glycol, propylene glycol, or preferably ethylene glycol, at room temperature so that the salt concentration is 1M.
  • a solvent such as alkylene glycol, such as ethylene glycol, propylene glycol, or preferably ethylene glycol, at room temperature so that the salt concentration is 1M.
  • a solvent such as alkylene glycol, such as ethylene glycol, propylene glycol, or preferably ethylene glycol
  • the obtained solution is transferred to a baking container, and it is 0.1 to 10 per minute from normal temperature under normal pressure. C, preferably at a rate of 0.5 to 5 ° C per minute and heated to 100 to 200 ° C, preferably 200 ° C, to completely remove the solvent. Thereafter, the temperature is further increased to 400 ° C to 800 ° C, preferably 600 ° C at a rate of 5 to 30 ° C per minute, preferably 10 to 20 ° C per minute. While maintaining, for example, the residue is calcined for 1 to 10 hours, preferably about 5 hours, to fix the perovskite structure of the catalyst.
  • oxygen or air is introduced into the firing container at a flow rate of 0.5 liter Z minutes or more, preferably 1 liter Z minutes or more. Do it while sending.
  • the obtained fired product is cooled to room temperature and then pulverized to obtain particles of a perovskite complex oxide catalyst having a target particle size.
  • the pulverization is performed using a mortar, for example, if it is 50 g of catalyst particles, 20 minutes, and crushing for a total of 1 to 6 hours, preferably about 4 hours.
  • the diesel particulate filter of the present invention can be manufactured, for example, according to the following steps.
  • the particles of the perovskite complex oxide catalyst of the present invention are suspended in an alcoholic aqueous solution.
  • the alcoholic aqueous solution contains alcohol and water which are liquid at room temperature (25 ° C).
  • the alcohol include alcohols having 1 to 3 carbon atoms such as methanol, ethanol, n-propanol, and isopropanol. Ethanol is preferable.
  • Alcohol is contained, for example, 85 to 99%, preferably 92 to 97%, based on the total volume of the alcoholic aqueous solution.
  • ion-exchanged water can be used as the water.
  • water is contained, for example, in an amount of 1 to 15%, preferably 3 to 8%, based on the total volume of the alcoholic aqueous solution.
  • the alcoholic aqueous solution may contain a ionic surfactant that dissolves in alcohol as a dispersant.
  • the dispersant may be contained in an amount of 0.2 to 0.6% by mass, preferably 0.4 to 0.5% by mass, based on the mass of the velovskite complex oxide catalyst of the present invention.
  • the suspension suitably contains, for example, 5 to 50 g, preferably 10 to 30 g of the perovskite complex oxide catalyst particles of the present invention in 1 liter of an alcoholic aqueous solution.
  • (2-2-2) A step in which the nonwoven fabric is used as a negative electrode, a potential difference is applied between the positive electrode and the negative electrode in the suspension, and the catalyst particles are adhered on the heat-resistant conductive fiber surface of the nonwoven fabric of the present invention.
  • a potential difference is applied to the suspension, and the catalyst particles of the present invention are adhered to the surface of the heat-resistant conductive fibers of the nonwoven fabric of the present invention using so-called electrophoresis.
  • particles of the perovskite complex oxide catalyst of the present invention are dispersed. Around these particles, hydrogen ions separated by hydraulic force are attached and are positively charged in the suspension. Therefore, by applying a potential difference between the positive electrode and the negative electrode in the suspension using the nonwoven fabric as the negative electrode, the positively charged catalyst particles gather on the surface of the heat-resistant fiber of the nonwoven fabric, which is the negative electrode, and adhere by electrostatic energy.
  • the positive electrode for example, a carbon electrode or CZC (carbon composite) can be used.
  • a non-woven fabric of the present invention preferably a metal mesh sandwiching the non-woven fabric of the present invention, for example, a stainless steel mesh (pore diameter 0.5 to 5 mm, preferably 1 to 3 mm, opening 5 to 50 mm, preferably 10 ⁇ 30mm).
  • a potential difference is applied between the positive electrode and the negative electrode.
  • the potential difference is, for example, voltage: 50 to 200V, preferably ⁇ 100 to 150V, current: 100 to 2000 mA, preferably 200 to 1000 mA, more preferably 200 to 800 mA, 5 to 30 minutes, preferably 5 Give ⁇ 20 minutes.
  • the nonwoven fabric of the present invention in which the catalyst particles adhere to the surface of the heat-resistant conductive fiber is taken out of the suspension after the electrophoresis. Thereafter, the aqueous alcoholic solution is naturally dried at room temperature, for example, for 1 to 10 hours, preferably for about 5 hours, and the suspension is also removed. Further, the nonwoven fabric is sintered to carry the catalyst particles on the surface of the heat-resistant conductive fiber. Sintering uses, for example, an electric furnace or the like, for example, 400 to 1000 ° C, preferably 600 to 900 ° C, more preferably 800 ° C for 1 to 5 hours, preferably 1.5 to 3 For 2 hours, more preferably 2 hours.
  • the catalyst particles supported on the heat-resistant conductive fiber surface in this way have no change in the size or structure of the particles before and after the support.
  • the diesel particulate filter of the present invention is used in a purification apparatus for diesel engine exhaust gas.
  • a diesel engine exhaust gas purifier is attached to the rear of the diesel engine combustion chamber and in front of the exhaust port for releasing the exhaust gas into the atmosphere.
  • a diesel engine exhaust gas purification apparatus includes the diesel particulate filter of the present invention.
  • the exhaust gas is introduced into the purification device, passes through a diesel particulate filter in the purification device, and then released to the outside of the purification device.
  • particulate matter (PM) and nitrogen oxides (NOx) contained in the exhaust gas are trapped and put into the gaps (holes) of the heat-resistant fibers contained in the diesel particulate filter. accumulate.
  • the deposited particulate matter (PM) and nitrogen oxides (NOx) react on the bottom bskite-type complex oxide catalyst supported on the surface of the heat-resistant fiber and react with carbon C, which is the main component of PM.
  • NOx O undergoes oxidation reaction to become CO, and at the same time NO
  • NOx may be decomposed due to the fact that the reaction formula of the actual reaction is more complicated.
  • the velovskite complex oxide catalyst of the present invention works well. In other words, under excessive NOx, ionic conductivity is improved at high temperatures, the catalytic reduction action is activated, and nitrogen oxides NOx are decomposed well. On the other hand, even under excessive C, the perovskite-type composite oxide catalyst of the present invention can efficiently oxidize C due to the activity of the catalytic reaction between NOx and C, which has high low-temperature activity. Can do.
  • the diesel particulate filter in the purification apparatus for diesel engine exhaust gas of the present invention has one layer or two layers of a non-woven fabric of heat-resistant fiber carrying the velovskite type composite oxide catalyst of the present invention. It may be a laminate of more than one layer.
  • a non-woven fabric of heat-resistant fiber carrying the velovskite type composite oxide catalyst of the present invention may be a laminate of more than one layer.
  • PM particulate matter
  • a three-layer structure provided with the following nonwoven fabric layer is appropriate.
  • the thickness of the nonwoven fabric laminate is, for example, 5 to 50 mm, and preferably 10 to 30 mm. is there.
  • the diesel particulate filter in the diesel engine exhaust gas purification apparatus of the present invention comprises a non-woven fabric made of a heat-resistant fiber carrying the bevelskite-type composite oxide catalyst of the present invention.
  • the laminate may be sandwiched between a sheet of heat-resistant metal plates and the resulting laminate may be bent into a bellows shape.
  • the contact area of the exhaust gas can be increased, pressure loss when particulate matter (PM) remains on the nonwoven fabric can be prevented, and the purification equipment can be made compact. it can.
  • examples of the heat-resistant metal plate include stainless steel (such as SUS301 and SUS304).
  • the thickness of the heat-resistant metal plate is, for example, 1 to 8 mm, preferably 2 to 5 mm.
  • the diesel engine exhaust gas purification device of the present invention is a diesel particulate filter heating device for preventing clogging of the diesel particulate filter due to particulate matter (PM) remaining on the nonwoven fabric. May be included.
  • Heating temperature is below the heat resistant temperature of the heat resistant fiber or catalyst used, for example, when using silicon carbide fiber or when using a perovskite complex oxide catalyst containing Mn as the catalyst, 800 ° C or less, More preferably, the temperature is set to 600 ° C or lower.
  • a microwave irradiation device is preferable. The microwave irradiation device can raise the temperature of the nonwoven fabric in a short time and is easy to control the temperature. When using the microwave irradiation apparatus, it is necessary to use silicon carbide fiber or silicon fiber, which is a microwave absorber, as the heat-resistant fiber of the present invention.
  • catalyst particles are used for X-ray analysis and confirmed to have a perovskite structure with a composition ratio of La Sr CoO.
  • the average particle size of the obtained catalyst particles was about 10 nm as measured with a scanning electron microscope.
  • the specific surface area was measured by the BET method according to JIS R1626 and found to be 50 m 2 / g.
  • a non-woven fabric made of silicon carbide fiber (Tyranno Fiber (registered trademark) heat-resistant grade ZM (Si-CO-Zr composition ratio 56: 34: 9: 1))) (Tosco Ceramic manufactured by Tosco Corporation) Fiber felt) (length x width x thickness: 290 x 210 x I. 57 mm) sandwiched between stainless steel wire meshes with a hole diameter of 2 mm and openings of 20 mm was used.
  • the silicon carbide fiber used has a fiber diameter of 10 / ⁇ ⁇ , a fiber length of 40 mm, a tensile strength of 3.4 GPa (measured in accordance with JIS K-7023), and the nonwoven fabric has a basis weight of 380 g / m 2 and a strength. It has a density of 0.24 g / cm 3 .
  • two carbon plates (length X width X thickness: 300 X 240 X 5 mm) were used as the positive electrode. These positive electrodes were placed above and below the negative electrode so as to be parallel to the negative electrode with an interval of 15 mm.
  • a DC voltage of 100 V and 800 mA was applied to the positive electrode and the negative electrode for 15 minutes, and particles of the velovskite complex oxide catalyst were supported on the silicon carbide fiber. Thereafter, the nonwoven fabric was taken out of the suspension, naturally dried at room temperature for 5 hours, and then sintered at 800 ° C. for 2 hours. Gain On the resulting non-woven silicon carbide fiber, 1.0% by mass of catalyst particles was supported with respect to the total mass of the non-woven fabric and the catalyst particles.
  • the supported catalyst particles are perovskite type complex oxides having a composition of La Sr CoO by X-ray analysis.
  • the particles of the velovskite complex oxide catalyst of the present invention have a multilayer structure, and the thickness of the layer was about 50 nm as measured by a scanning electron microscope.
  • Example 1 and Comparative Example 1 were evaluated for their ability to decompose particulate matter (PM) and nitrogen oxides (NOx).
  • the evaluation was conducted by preparing a test gas simulating the exhaust gas emitted from the diesel engine and passing this test gas to the purification equipment filled with the diesel particulate filter obtained in Example 1 and Comparative Example 1.
  • the gas components that passed through the filter were analyzed by gas chromatography.
  • a test gas a gas having a composition of 5% 0 -0.5% NO-He was used.
  • purification purification
  • the equipment used was a stainless steel SUS304 cylindrical reaction tube with an inner diameter of 15 mm and a height of 300 mm, with an exhaust gas inlet and outlet on the upper and lower surfaces.
  • This reaction tube three diesel particulate filters having a diameter of 15 mm and a thickness of 1.57 mm were stacked and filled, and the exhaust gas was set to pass through the three diesel particulate filters.
  • the diesel particulate filter used was carbon black (Tokai Black # 8500 grade 14nm (particle size 14nm) manufactured by Tokai Carbon Co., Ltd.) in order to reproduce the state where particulate matter (PM) was collected by the filter. , 6% by mass was used with respect to the mass of the diesel particulate filter used.
  • test gas was passed through a purification apparatus at a flow rate of 40 mlZ, and then generated CO, CO, and N N O were analyzed at 15 minute intervals with a gas chromatograph (manufactured by Shimadzu Corporation). Examination
  • test gas temperature (temperature outside the reaction tube) was increased from 200 ° C to 700 ° C at 1 ° C / min.
  • NO nitrogen oxides
  • Example 1 The test result of Example 1 is shown in Graph 1, and the test result of Comparative Example 1 is shown in Graph 2.
  • Example 1 As shown in graphs 1 and 2, the concentration of CO and CO in the test gas was determined in Example 1. Indicates a higher concentration than Comparative Example 1. Further, although not shown in the graph, in Example 1, CO is not generated (Oppm) —in the comparative example, CO is generated in each temperature region (for example, 485. 290 ppm at C, 500. 375ppm for C, 515. 298ppm for C). Therefore, it can be seen that the diesel particulate filter of Example 1 has a high particulate matter (PM) decomposition capacity, and that the treated carbon C becomes completely CO and can be released into the atmosphere.
  • PM particulate matter
  • Example 1 has a higher concentration than that of Comparative Example 1.
  • the temperature at which N and N O start to be generated is 365 ° C in Example 1.
  • Comparative Example 1 is around 410 ° C. Therefore, the diesel particulate filter of Example 1 has a high ability to decompose nitrogen oxides (NOx) and can effectively remove nitrogen oxides (NOx) even when the sample gas is at a relatively low temperature. It can be seen that it can be decomposed.
  • FIG. 1 is a scanning electron micrograph on the surface of silicon carbide fiber of the diesel particulate filter obtained in Example 1.
  • FIG. 2 is a scanning electron micrograph on the surface of silicon carbide fiber of the diesel particulate filter obtained in Comparative Example 1.

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Abstract

A diesel particulate filter capable of eliminating particulate matter (PM) emitted from diesel engine exhaust gas and being a cause of air pollution and dust pollution, particularly together with particulate matter (PM) contained in diesel engine exhaust gas with NOx satisfactorily removed, more particularly capable of simultaneously eliminating suspended particulate matter (SPM) of small particle diameter and nitrogen oxides (NOx). There is provided a diesel particulate filter having a nonwoven fabric of thermostable fiber and, carried on the surface of the thermostable fiber, a perovskite composite oxide catalyst, characterized in that the composite oxide catalyst consists of particles of 0.1 to 100 nm average diameter.

Description

明 細 書  Specification
ディーゼルパーティキュレートフィルタ及びこれを用いた浄ィ匕装置 技術分野  Diesel particulate filter and purification apparatus using the same
[0001] 本発明は、ディーゼルエンジンカゝら排出されるの排ガス中に含まれる微粒子状物質 (PM)と窒素酸ィ匕物 (NOx)の同時かつ完全な除去を可能にするディーゼルパーティ キュレートフィルタ及びこれを用 、た浄化装置に関するものである。  [0001] The present invention relates to a diesel particulate filter that enables simultaneous and complete removal of particulate matter (PM) and nitrogen oxides (NOx) contained in exhaust gas discharged from a diesel engine car. And a purification apparatus using the same.
背景技術  Background art
[0002] ディーゼルエンジンは、その優れた燃費と耐久性から、 日本ではトラックを中心に幅 広く使用されている。特に欧州では、優れた燃費と地球温暖化ガス COの発生量が  [0002] Diesel engines are widely used mainly in trucks in Japan because of their excellent fuel economy and durability. Especially in Europe, excellent fuel economy and global warming gas CO emissions
2  2
少ない事から、乗用自動車にも多く利用されている。  Because it is scarce, it is also widely used in passenger cars.
一方で、ディーゼルエンジンからは、多量の有害な粒子状物質 (PM)及び窒素酸化 物 (NOx)が排出される。 PMは、主に炭素からなる固体塊状物質である。 PMは、大 気汚染、粉塵公害の原因となるといわれている。 PMのうち、特に粒径が 10 /z m以下 のものは浮遊粒子状物質 (SPM)と呼ばれる。 SPMは、大気中に長時間浮遊し、肺 や気管などに沈着して呼吸器に悪い影響を与えるほか、発ガン性のおそれがあると 言われている。また、窒素酸ィ匕物 (NOx)は、酸性雨や光化学オキシダントの原因物 質であると言われている。従って、ディーゼルエンジン排ガスからの PM及び NOの  On the other hand, diesel engines emit large amounts of harmful particulate matter (PM) and nitrogen oxides (NOx). PM is a solid massive substance mainly composed of carbon. PM is said to cause air pollution and dust pollution. Among PMs, those with a particle size of 10 / z m or less are called suspended particulate matter (SPM). SPM is said to float in the atmosphere for a long time, deposit in the lungs, trachea, etc., adversely affect the respiratory tract and possibly cause cancer. Nitrogen oxides (NOx) are said to cause acid rain and photochemical oxidants. Therefore, PM and NO emissions from diesel engine exhaust
X  X
十分な除去が求められている。  Sufficient removal is required.
[0003] これら粒子状物質 (PM)及び窒素酸化物 (NOx)を除去する方法として、ディーゼル パーティキュレートフィルタ (DPF)をディーゼルエンジンの排ガス側に設ける方法が 知られている。古くから用いられてきたフィルタとして、炭化珪素系の無機繊維の不織 布を用いたものが挙げられる。このフィルタは、排ガスに含まれる PMを不織布で捕集 し、高温 (約 600°C)に加熱して、 PMの構成物である炭素 (C)や炭化水素 (HC)を CO [0003] As a method for removing these particulate matter (PM) and nitrogen oxide (NOx), a method of providing a diesel particulate filter (DPF) on the exhaust gas side of a diesel engine is known. As a filter that has been used for a long time, a filter using a nonwoven fabric of silicon carbide-based inorganic fibers can be cited. This filter collects PM contained in exhaust gas with a non-woven fabric and heats it to a high temperature (approximately 600 ° C) to convert the components of PM, carbon (C) and hydrocarbons (HC), into CO.
2 や H Oにかえて放出する。しかし、このフィルタは、 NOxを低減する効果はない (特許 Release in place of 2 or H 2 O. However, this filter has no effect on reducing NOx (patented)
2 2
文献 1参照)。  Reference 1).
また、このような不織布に含まれる繊維表面に窒素酸化物 NOxの還元作用を有す るぺロブスカイト型化合物を担持したディーゼルパティキュレートフィルタも開示され ている (特許文献 2参照)。しかし、力かるぺロブスカイト型化合物は、 PMを除去する 能力に乏しぐ特許文献 2においても、触媒によらず、酸化雰囲気下で加熱して熱処 理することにより、 PMを除去している。また、特許文献 2の出願当時、できるだけ小さ な粒径と高 、比表面積を有するベロブスカイト型化合物の触媒を得る方法として、成 分酸化物や炭酸塩を混合焼成する 、わゆるセラミック法を用いてぺロブスカイト型化 合物の粒子を製造する方法があった。しかし、通常は l〜5m2Zg程度の比表面積で あり、粒子径も、せいぜい 1〜3 μ m程度にとどまつていたため、 1 μ m未満のぺロブ スカイト型化合物の粒子を不織布の繊維表面上に担持したディーゼルパティキユレ ートフィルタは存在しなかった。 Also disclosed is a diesel particulate filter carrying a perovskite-type compound having a nitrogen oxide NOx reducing action on the surface of fibers contained in such a nonwoven fabric. (See Patent Document 2). However, even in Patent Document 2 where the powerful perovskite type compound lacks the ability to remove PM, PM is removed by heating and heat treatment in an oxidizing atmosphere, regardless of the catalyst. In addition, at the time of filing of Patent Document 2, as a method of obtaining a catalyst of a velovskite type compound having as small a particle size, high size and specific surface area as possible, a so-called ceramic method is used in which component oxides and carbonates are mixed and fired. There has been a method for producing particles of teplovskite type compounds. However, it usually has a specific surface area of about 1 to 5 m 2 Zg, and the particle size stayed at about 1 to 3 μm. Therefore, particles of perovskite-type compounds of less than 1 μm were placed on the surface of the nonwoven fabric. There was no diesel particulate filter supported above.
[0004] さらに、ぺロブスカイト型ゃスピネル型の複合酸化触媒を、アルコキシド法ゃ硝酸塩 単純浸漬法で、炭化珪素繊維の表面に担持させた炭化珪素繊維からなるディーゼ ルパティキュレートフィルタが知られて 、る（特許文献 3参照)。 [0004] Further, there is known a diesel particulate filter comprising a silicon carbide fiber having a perovskite type spinel type composite oxidation catalyst supported on the surface of a silicon carbide fiber by an alkoxide method or a simple nitrate dipping method. (See Patent Document 3).
しかし、アルコキシド法ゃ硝酸塩単純浸漬法等で製造されるぺロブスカイト型ゃスピ ネル型の複合酸化触媒は、比表面積が小さく (約 0. 5m2Zg)、排気ガスと触媒の接 触が十分に行われない。また、この複合酸化触媒は、不織布等の支持体を被覆する ように担持されるものであって、粒子構造を有しない。よって、このようなディーゼルパ ティキュレートフィルタでは、 PM (炭素)を COに変換し、かつ、 NOxを完全に窒素に However, the perovskite type spinel type composite oxidation catalyst manufactured by the alkoxide method or the simple nitrate dipping method has a small specific surface area (about 0.5m 2 Zg), and the exhaust gas and the catalyst have sufficient contact. Not done. Further, this composite oxidation catalyst is supported so as to cover a support such as a non-woven fabric and does not have a particle structure. Therefore, in such a diesel particulate filter, PM (carbon) is converted to CO and NOx is completely converted to nitrogen.
2  2
還元することは困難である。  It is difficult to reduce.
以上のことから、ディーゼルエンジンから排出される排ガス中の PM及び NOxを無 害化する高性能なディーゼルパティキュレートフィルタ及びそれを用いた浄ィ匕装置の 開発が強く望まれている。  In light of the above, development of a high-performance diesel particulate filter that renders PM and NOx in exhaust gas discharged from a diesel engine harmless and a purifier using it is strongly desired.
[0005] 特許文献 1 :特開平 7— 11933号公報 Patent Document 1: Japanese Patent Laid-Open No. 7-11933
特許文献 2 :特開 2002— 301320号公報  Patent Document 2: JP 2002-301320 A
特許文献 3：特開 2003 - 239722号公報  Patent Document 3: Japanese Patent Laid-Open No. 2003-239722
発明の開示  Disclosure of the invention
発明が解決しょうとする課題  Problems to be solved by the invention
[0006] 本発明の第一の目的は、ディーゼルエンジン排ガス力 排出される大気汚染、粉 塵公害の原因となる、粒子状物質 (PM)、特に及び NOの十分な除去ディーゼルェ ンジンの排ガス中に含まれる粒子状物質 (PM)、特に粒径の小さな浮遊粒子状物質 (SPM)及び窒素酸ィ匕物 (NOx)の除去を同時に行う能力を持つディーゼルパティキュ レートフィルタを提供することにある。 [0006] The first object of the present invention is to sufficiently remove particulate matter (PM), especially NO, which causes air pollution and dust pollution that are emitted from diesel engine exhaust gas power. Providing diesel particulate filters with the ability to simultaneously remove particulate matter (PM), particularly small suspended particulate matter (SPM) and nitrogen oxides (NOx), contained in engine exhaust gas There is to do.
本発明の第二の目的は、耐熱性繊維からなる不織布と、該耐熱性繊維の表面に担 持された粒子状複合酸ィ匕物触媒とを含むディーゼルパティキュレートフィルタを提供 することにある。  A second object of the present invention is to provide a diesel particulate filter comprising a nonwoven fabric made of heat resistant fibers and a particulate composite oxide catalyst supported on the surface of the heat resistant fibers.
本発明の第三の目的は、上記不織布表面上で、粒子状物質 (PM)、特に粒径の 小さな浮遊粒子状物質 (SPM)を捕捉して酸ィ匕 ·除去し、かつ窒素酸ィ匕物 (NOx)も同 時に還元 '除去し得る、高効率でディーゼルエンジン排ガスを無害化する、コンパクト で高性能なディーゼルパティキュレートフィルタ及びディーゼルエンジン排ガス用の 浄ィ匕装置を提供することにある。  The third object of the present invention is to capture and remove particulate matter (PM), particularly suspended particulate matter (SPM) having a small particle diameter, on the surface of the nonwoven fabric, and to remove nitrogenous acid. The object is to provide a compact and high-performance diesel particulate filter and a purification device for diesel engine exhaust gas, which can reduce and remove substances (NOx) at the same time, detoxify diesel engine exhaust gas with high efficiency.
本発明の第四の目的は、耐熱性繊維からなる不織布と、該耐熱性繊維の表面に担 持された複合酸化物触媒とを含むディーゼルパティキュレートフィルタの製造方法を 提供することにある。  A fourth object of the present invention is to provide a method for producing a diesel particulate filter comprising a non-woven fabric made of heat-resistant fibers and a composite oxide catalyst supported on the surface of the heat-resistant fibers.
課題を解決するための手段 Means for solving the problem
本発明者らは、上記目的を達成するために鋭意研究した結果、特定の粒径を有す るべ口ブスカイト型複合酸化物触媒の粒子を特定の耐熱性繊維からなる不織布の表 面に担持させたディーゼルパティキュレートフィルタ力 良好な粒子状物質 (PM)及 び窒素酸ィ匕物 (NOx)の同時除去性能を示すことを見出した。  As a result of diligent research to achieve the above object, the present inventors have supported the surface of a non-woven fabric made of a specific heat-resistant fiber with particles of a mouth-bushite complex oxide catalyst having a specific particle size. It was found that the diesel particulate filter showed good simultaneous removal performance of particulate matter (PM) and nitrogen oxides (NOx).
具体的に、本発明は、  Specifically, the present invention
1.耐熱性繊維からなる不織布と、該耐熱性繊維の表面に担持されたぺロブスカイト 型複合酸ィ匕物触媒とを含むディーゼルパティキュレートフィルタであって、前記複合 酸化物触媒が 0. 1〜： LOOnmの平均粒子径を有する粒子であることを特徴とするディ ーゼルパティキュレートフィルタに関する。  1. A diesel particulate filter comprising a nonwoven fabric composed of heat-resistant fibers and a perovskite-type composite oxide catalyst supported on the surface of the heat-resistant fibers, wherein the composite oxide catalyst is 0.1 to : It relates to a diesel particulate filter characterized by being particles having an average particle size of LOOnm.
2.前記べ口ブスカイト型複合酸化物触媒が、式 (I)：  2. The above-mentioned mouthbskite-type composite oxide catalyst has the formula (I):
A B C O (I) A B C O (I)
P q r 3  P q r 3
(式中、 A、 B及び Cは、互いに同一でも異なっていてもよぐ K、 Ni、 Sr、 Co、 La、 C u、 V、 Mn、 Fe、 Cs、 Ba、 Ce、 Li, Pd力らなる群力ら選択され; p及び qは、 0. 5<p < 1、 0< q< 0. 5、 p + q= lを満たし、 rは、 0又は 1である） (In the formula, A, B and C may be the same or different from each other. K, Ni, Sr, Co, La, Cu, V, Mn, Fe, Cs, Ba, Ce, Li, Pd force, etc. Group forces are selected; p and q are 0.5 <p <1, 0 <q <0.5, p + q = l, r is 0 or 1)
で表される、上記 1に記載のディーゼルパティキュレートフィルタに関する。  The diesel particulate filter according to 1 above, represented by:
[0008] 3.前記ぺロブスカイト型複合酸化物触媒が、 La K CoO、 La Sr CoO又は La [0008] 3. The perovskite-type composite oxide catalyst is La K CoO, La Sr CoO or La
0.9 0.1 3 0.8 02 3 0.75 0.9 0.1 3 0.8 02 3 0.75
K MnOである、上記 1に記載のディーゼルパティキュレートフィルタに関する。 2. The diesel particulate filter according to 1 above, which is K MnO.
0.25 3  0.25 3
4.前記ぺロブスカイト型複合酸ィ匕触媒の BET法で測定した比表面積が 10m2/g以 上である、上記 1〜3のいずれ力 1に記載のディーゼルパティキュレートフィルタに関 する。 4. The diesel particulate filter according to any one of the above 1 to 3, wherein the perovskite-type complex oxide catalyst has a specific surface area of 10 m 2 / g or more measured by BET method.
5.前記不織布が、厚さ 0. 3〜： L0mm、かつ、力さ密度 0. 05〜： L OgZcm3を有する 、上記 1〜4のいずれ力 1に記載のディーゼルパティキュレートフィルタに関する。5. The nonwoven fabric, thickness 0.1. 3 to: L0mm, and the force of density 0. 05～: having L OgZcm 3, relates to a diesel particulate filter according to any force 1 above 1-4.
6.上記 1〜5のいずれ力 1に記載のディーゼルパティキュレートフィルタを用いたディ ーゼルエンジン力 排出される排ガス用の浄ィ匕装置に関する。 6. Diesel engine power using the diesel particulate filter described in any one of 1 to 5 above. The present invention relates to a purifier for exhaust gas discharged.
[0009] 7.耐熱性導電性繊維からなる不織布と、該耐熱性導電性繊維の表面に担持された 0. 1〜 1 OOnmの平均粒子径を有するぺロブスカイト型複合酸化物触媒の粒子とを 含むディーゼルパティキュレートフィルタの製造方法であって、  [0009] 7. A non-woven fabric comprising heat-resistant conductive fibers and particles of a perovskite-type composite oxide catalyst having an average particle diameter of 0.1 to 1 OOnm supported on the surface of the heat-resistant conductive fibers. A diesel particulate filter manufacturing method comprising:
(1)前記ぺロブスカイト型複合酸ィ匕物触媒の粒子をアルコール性水溶液中に懸濁し た懸濁液中に前記不織布を浸漬する工程、  (1) a step of immersing the nonwoven fabric in a suspension obtained by suspending particles of the perovskite-type composite oxide catalyst in an alcoholic aqueous solution;
(2)前記不織布を負極とし、前記懸濁液中の正極と前記負極との間に電位差を与え、 前記不織布の耐熱性導電性繊維表面上に前記粒子を付着させる工程、及び (2) using the nonwoven fabric as a negative electrode, applying a potential difference between the positive electrode and the negative electrode in the suspension, and attaching the particles onto the heat-resistant conductive fiber surface of the nonwoven fabric; and
(3)前記耐熱性導電性繊維表面上に前記粒子が付着した前記不織布を前記懸濁液 から取り出し、前記不織布を焼結する工程、 (3) removing the nonwoven fabric with the particles attached on the heat-resistant conductive fiber surface from the suspension, and sintering the nonwoven fabric;
を含む方法に関する。  Relates to a method comprising:
8.上記 7に記載の製造方法によって得られる耐熱性導電性繊維力 なる不織布と、 該耐熱性導電性繊維の表面に担持された 0. 1〜： LOOnmの平均粒子径を有するぺ 口ブスカイト型複合酸ィ匕物触媒とを含むディーゼルパティキュレートフィルタに関する 発明を実施するための最良の形態  8. Non-woven fabric having heat-resistant conductive fiber strength obtained by the production method described in 7 above, and a pebskite type having an average particle diameter of 0.1 to: LOOnm supported on the surface of the heat-resistant conductive fiber BEST MODE FOR CARRYING OUT THE INVENTION Best Mode for Carrying Out the Invention A diesel particulate filter containing a composite oxide catalyst
[0010] (1)ディーゼルパティキュレートフィルタ [0010] (1) Diesel particulate filter
本発明のディーゼルパティキュレートフィルタは、耐熱性繊維からなる不織布と、該 耐熱性繊維の表面に担持されたべ口ブスカイト型複合酸化物触媒とを含む。以下、 上記不織布及びべ口ブスカイト型複合酸ィ匕物触媒とについて説明する。 The diesel particulate filter of the present invention comprises a nonwoven fabric composed of heat-resistant fibers, And a mouth bumskite complex oxide catalyst supported on the surface of the heat resistant fiber. Hereinafter, the non-woven fabric and the mouthbushite complex oxide catalyst will be described.
[0011] (1-1)不織布  [0011] (1-1) Nonwoven fabric
本発明の不織布は、耐熱性繊維力もなる。  The nonwoven fabric of the present invention also has heat resistant fiber strength.
本発明の耐熱性繊維は、 800°C以上、好ましくは、 1000°C以上の耐熱性を有する 繊維である。  The heat-resistant fiber of the present invention is a fiber having a heat resistance of 800 ° C or higher, preferably 1000 ° C or higher.
また、本発明の耐熱性繊維は、ベロブスカイト型複合酸化物触媒粒子を電気泳動 法により付着させるためにも、耐熱性導電性繊維であることが好ましい。ここで、本発 明の耐熱性導電性繊維は、例えば、 1. 4 Ω 'cm以下、好ましくは、 0. 1 Ω 'cm以下 の電気抵抗を有することが好まし 、。  The heat-resistant fiber of the present invention is preferably a heat-resistant conductive fiber in order to adhere the velovskite complex oxide catalyst particles by electrophoresis. Here, the heat-resistant conductive fiber of the present invention preferably has an electric resistance of, for example, 1.4 Ω′cm or less, preferably 0.1 Ω′cm or less.
さらに、本発明の耐熱性繊維は、 K等を含むアルカリ金属酸化物を担持するために も、耐アルカリ性であることが適当である。好ましくは、耐アルカリ性の程度は、 2. 0% NaCl水溶液に浸漬後、空気中 1000°C X 2時間熱処理された繊維の引張強度を測 定し、強度低下をしないものであることが適当である。  Furthermore, it is appropriate that the heat resistant fiber of the present invention is alkali resistant in order to support an alkali metal oxide containing K or the like. Preferably, the degree of alkali resistance is appropriately determined by measuring the tensile strength of a fiber that has been immersed in a 2.0% NaCl aqueous solution and then heat-treated in air at 1000 ° C. for 2 hours to reduce the strength. .
[0012] 本発明の耐熱性繊維は、無機系或いは有機系繊維であることが適当である。ここで 、無機系繊維としては、珪素を主体とした珪素繊維、炭化珪素繊維、アルミナ繊維が 挙げられる。より好ましくは、耐アルカリ性能を上げるため、上記炭化珪素繊維は、 Ti 、 Zr及び/又は A1等の成分を含んでいてもよい。これらの成分は、繊維全体に対し て 0. 1〜2%質量％含まれていることが適当である。 [0012] The heat-resistant fiber of the present invention is suitably an inorganic or organic fiber. Here, examples of the inorganic fibers include silicon fibers mainly composed of silicon, silicon carbide fibers, and alumina fibers. More preferably, the silicon carbide fiber may contain components such as Ti, Zr and / or A1 in order to improve alkali resistance. These components are suitably contained in an amount of 0.1 to 2% by mass based on the entire fiber.
このような繊維としては、例えば、炭化珪素繊維として、二カロン繊維（Si— O— C 組成比 57.2： 32.7： 10、日本カーボン株式会社製)、チラノ繊維 (登録商標)耐熱ダレ ード ZM (Si— C— O— Zr 組成比 56 : 34: 9 : 1)、チラノ繊維 (登録商標）耐熱グレード S (Si-O-C-Ti 組成比 50 : 30 : 18 : 2)チラノ繊維 (登録商標）耐熱グレード SA (Si -O-C-Al 組成比 67 : 31 : 1 : 2) (チラノ繊維 (登録商標）は、全て、宇部興産株式 会社製)が好ましい。  Examples of such fibers include silicon carbide fibers, two-calon fibers (Si—O—C composition ratio 57.2: 32.7: 10, manufactured by Nippon Carbon Co., Ltd.), Tyranno Fiber (registered trademark) heat-resistant Darade ZM ( Si—C—O—Zr composition ratio 56: 34: 9: 1), Tyranno Fiber (registered trademark) heat-resistant grade S (Si-OC-Ti composition ratio 50: 30: 18: 2) Tyranno fiber (registered trademark) heat resistant Grade SA (Si-OC-Al composition ratio 67: 31: 1: 2) (Tyranno fiber (registered trademark) is all manufactured by Ube Industries, Ltd.) is preferable.
また、有機系繊維としては、例えば、炭素繊維が挙げられる。  Moreover, as an organic fiber, carbon fiber is mentioned, for example.
本発明の耐熱性繊維は、これらの繊維を 2種以上組み合わせたものであってもよ ヽ [0013] 本発明の耐熱性繊維の直径は、平均で、例えば、 3〜20 μ m、好ましくは、 9〜14 μ mであることが適当である。直径が 3 μ m以上であれば、繊維自体が飛散して発ガ ン性のある物質を大気中に放出することもな 、ので好ま 、。 The heat-resistant fiber of the present invention may be a combination of two or more of these fibers. [0013] The average diameter of the heat-resistant fiber of the present invention is, for example, 3 to 20 μm, preferably 9 to 14 μm. If the diameter is 3 μm or more, it is preferable because the fibers themselves scatter and do not release gas-generating substances into the atmosphere.
本発明の耐熱性繊維の繊維長は、平均で、例えば、 10〜： LOOmm、好ましくは、 3 The fiber length of the heat-resistant fiber of the present invention is, for example, 10 to: LOOmm, preferably 3
0〜60mmであることが適当である。 It is appropriate to be 0 to 60 mm.
本発明の耐熱性繊維の引張強さは、 JIS K-7023で測定して、例えば、 l〜5GPa好 ましくは、 2〜4GPaであることが適当である。  The tensile strength of the heat resistant fiber of the present invention is, for example, 1 to 5 GPa, preferably 2 to 4 GPa as measured by JIS K-7023.
[0014] 本発明の不織布は、上記耐熱性繊維を、公知の方法、例えば、スパンボンド法、或 いは、特開 2000-199160「無機短繊維フェルトの製造方法及び装置」により不織布と したものであり得る。 [0014] The nonwoven fabric of the present invention is obtained by converting the above heat-resistant fiber into a nonwoven fabric by a known method, for example, a spunbond method, or JP-A 2000-199160 "Method and apparatus for producing inorganic short fiber felt". It can be.
本発明の不織布の厚さは、例えば、 0. 3〜： LOmm、好ましくは、 0. 5〜5mm、より 好ましくは、 l〜3mmであることが適当である。  The thickness of the nonwoven fabric of the present invention is, for example, 0.3 to LOmm, preferably 0.5 to 5 mm, more preferably 1 to 3 mm.
本発明の不織布の目付は、例えば、 50〜： LOOOgZm2、好ましくは、 100〜500g より好ましくは、 150〜400gZm2であることが適当である。 The basis weight of the nonwoven fabric of the present invention is, for example, 50 to: LOOOgZm 2 , preferably 100 to 500 g, more preferably 150 to 400 gZm 2 .
本発明の不織布の力さ密度は、例えば、 0. 05〜： L Og/cm3,好ましくは、 0. 1〜 0. 8gZcm3、より好ましくは、 0. 2〜0. 6gZcm3であることが適当である。力さ密度 が 0. 2gZcm3以上であれば、 PMの捕集性能は十分に維持することができ、また、 1 . OgZcm3以下であれば、本発明のディーゼルパティキュレートフィルタを用いた排 ガス用の浄ィ匕装置の排ガス圧力を低く押さえることができるので好ましい。 The strength density of the nonwoven fabric of the present invention is, for example, 0.05-: L Og / cm 3 , preferably 0.1-0.8 gZcm 3 , more preferably 0.2-0.6 gZcm 3 . Is appropriate. If the force density is 0.2 gZcm 3 or more, the PM collection performance can be sufficiently maintained, and if it is 1. OgZcm 3 or less, the exhaust gas using the diesel particulate filter of the present invention is used. This is preferable because the exhaust gas pressure of the water purification apparatus can be kept low.
[0015] (1-2)ベロブスカイト型複合酸化物触媒 [0015] (1-2) Velobskite complex oxide catalyst
上記不織布の耐熱性繊維の表面には、ベロブスカイト型複合酸化物触媒が担持さ れる。ここで、ぺロブスカイト型複合酸化物とは、基本組成 ABOで表され、 BO八面  On the surface of the heat-resistant fiber of the non-woven fabric, a velovskite complex oxide catalyst is supported. Here, the perovskite complex oxide is represented by a basic composition ABO,
3 6 体が立方単位格子の各隅を占めた構造を取るものである。酸素 12配位の空隙に A イオンが、 6配位空隙に Bイオンが入り構造を安定ィ匕している。一般に、 Aには、希土 類金属、アルカリ土類金属等のイオン半径の大きい金属イオンが、 Bには遷移金属ィ オンが入る。  It has a structure in which 3 6 bodies occupy each corner of the cubic unit cell. Oxygen 12-coordinate void enters A ion and 6-coordinate void enters B ion to stabilize the structure. In general, A contains a metal ion having a large ion radius, such as a rare earth metal or an alkaline earth metal, and B contains a transition metal ion.
本発明のぺロブスカイト型複合酸化物触媒は、 K、 Ni、 Sr、 Co、 La、 Cu、 V、 Mn、 Fe、 Cs、 Ba、 Ce、 Li及び Pdから選択される少なくとも 2種の元素を含むぺロブスカイ ト構造を有する複合酸化物触媒である。 The perovskite complex oxide catalyst of the present invention contains at least two elements selected from K, Ni, Sr, Co, La, Cu, V, Mn, Fe, Cs, Ba, Ce, Li and Pd. Perovsky A complex oxide catalyst having a structure.
[0016] より具体的には、本発明のベロブスカイト型複合酸化物触媒は、下記式 (I)：  [0016] More specifically, the velovskite complex oxide catalyst of the present invention has the following formula (I):
A B C O (I)  A B C O (I)
P q r 3  P q r 3
(式中、 A、 B及び Cは、互いに同一でも異なっていてもよぐ K、 Ni、 Sr、 Co、 La、 C u、 V、 Mn、 Fe、 Cs、 Ba、 Ce、 Li, Pd力らなる群力ら選択され; p及び qは、 0. 5<p < 1. 0、好ましく ίま、 0. 75≤ρ≤0. 95、 0< q< 0. 5、好ましく ίま、 0. 05≤q≤0. 2 5、 p + q= lを満たし、 rは、 0又は 1である）  (In the formula, A, B and C may be the same or different from each other. K, Ni, Sr, Co, La, Cu, V, Mn, Fe, Cs, Ba, Ce, Li, Pd force, etc. P and q are 0.5 <p <1.0, preferably ί, 0.575≤ρ≤0.95, 0 <q <0.5, preferably ί, 0. 05≤q≤0. 2 5, p + q = l, r is 0 or 1)
で表されてもよい。  It may be represented by
好ましい本発明のぺロブスカイト型複合酸化物触媒は、 La、 K、 Co、 Sr及び Mnか ら選択される少なくとも 2種の元素を含むものである。特に、式 (I)において、 Aが Laで あり、 Bが K、 Sr、 Li又は Csから選択され、 Cが Co又は Mnから選択され、 p及び qは、 p = 0. 7〜0. 9、q = 0. 1〜0. 3、 p + q= 1であり、 rは、 1であるィ匕合物力 子ましい。 より好ましい本発明のぺロブスカイト型複合酸化物触媒は、 La K CoO、La Sr  A preferred perovskite type complex oxide catalyst of the present invention contains at least two elements selected from La, K, Co, Sr and Mn. In particular, in formula (I), A is La, B is selected from K, Sr, Li or Cs, C is selected from Co or Mn, and p and q are p = 0.7 to 0.9 , Q = 0. 1 to 0.3, p + q = 1, and r is 1. More preferred perovskite complex oxide catalysts of the present invention are La K CoO, La Sr
0.9 0.1 3 0.8 0.2 0.9 0.1 3 0.8 0.2
CoO又は La K MnOである。 CoO or La K MnO.
3 0.75 0.25 3  3 0.75 0.25 3
[0017] 本発明のぺロブスカイト型複合酸化物触媒は、 0. 1〜： L00nm、好ましくは、 0. 5〜 50nm、より好ましくは、 l〜20nmの平均粒子径を有する粒子である。このような粒子 径の触媒を使用することにより、比表面積の大きな触媒を不織布の繊維表面上に担 持することができ、触媒性能を向上することができる。また、不織布の繊維表面上に 付着した触媒を焼結によって担持する場合、焼結温度を適宜下げることができる。例 えば、通常、： m程度の触媒粒子を使用する場合は 1000°Cで 2時間焼結する必 要があるところ、本発明のような小さな粒子径の触媒を使用する場合は、 400〜800 °C程度で 2時間焼結すれば十分な強度で担持できる。  [0017] The perovskite complex oxide catalyst of the present invention is a particle having an average particle diameter of 0.1 to: L00 nm, preferably 0.5 to 50 nm, more preferably 1 to 20 nm. By using a catalyst having such a particle size, a catalyst having a large specific surface area can be carried on the fiber surface of the nonwoven fabric, and the catalyst performance can be improved. In addition, when the catalyst adhering to the fiber surface of the nonwoven fabric is supported by sintering, the sintering temperature can be lowered appropriately. For example, usually: When using catalyst particles of about m, it is necessary to sinter at 1000 ° C for 2 hours, but when using a catalyst with a small particle size as in the present invention, 400-800 If it is sintered at about ° C for 2 hours, it can be supported with sufficient strength.
さらに、上記粒子径の触媒を使用することにより、少ない担持量で、耐熱性繊維表 面を完全かつ均一に被覆することができる。また、触媒と耐熱性繊維表面との接触を より強固に保つことが可能である。  Furthermore, by using the catalyst having the above particle diameter, the heat-resistant fiber surface can be completely and uniformly coated with a small amount of support. In addition, the contact between the catalyst and the heat-resistant fiber surface can be kept stronger.
[0018] 本発明のぺロブスカイト型複合酸ィ匕物触媒の BET法で測定した比表面積は、 10m 2m2/g以上、より好ましくは、 30m2/g以上、さらに好ましくは、 50m2/g以上、例え ば、 50〜： L00m2/gであることが適当である。ここで、本発明のぺロブスカイト型複合 酸ィ匕物触媒の比表面積は、 JIS R1626に準拠した BET法で測定される。 [0018] The specific surface area of the perovskite-type composite oxide catalyst of the present invention measured by the BET method is 10 m 2 m 2 / g or more, more preferably 30 m 2 / g or more, and still more preferably 50 m 2 / g. As described above, for example, 50-: L00m 2 / g is appropriate. Here, the perovskite type composite of the present invention The specific surface area of the acid oxide catalyst is measured by the BET method according to JIS R1626.
[0019] (1-3)ディーゼルパティキュレートフィルタ [0019] (1-3) Diesel particulate filter
本発明のディーゼルパティキュレートフィルタは、上述の耐熱性繊維、好ましくは耐 熱性導電性繊維からなる不織布と、この不織布の繊維表面に担持された上記べロブ スカイト型複合酸化物触媒の粒子とを含む。  The diesel particulate filter of the present invention comprises a nonwoven fabric composed of the above-mentioned heat-resistant fiber, preferably a heat-resistant conductive fiber, and particles of the above-mentioned belobskite complex oxide catalyst supported on the fiber surface of this nonwoven fabric. .
ベロブスカイト型複合酸化物触媒の粒子は、耐熱性繊維からなる不織布の質量に 対し、例えば、 0. 1 20質量％、好ましくは、 0. 5 5質量％含まれることが適当で ある。  It is appropriate that the particles of the velovskite type complex oxide catalyst are contained in an amount of, for example, 0.120% by mass, preferably 0.55% by mass, with respect to the mass of the nonwoven fabric made of heat-resistant fibers.
ぺロブスカイト型複合酸化物触媒の粒子は、不織布の耐熱性繊維の表面上に、一 様に、隙間なぐ均一に担持されている。不織布の耐熱性繊維の表面は、実質的に ぺロブスカイト型複合酸化物触媒の粒子で被覆されて ヽることが好まし ヽ。  The particles of the perovskite complex oxide catalyst are uniformly supported on the surface of the heat-resistant fiber of the nonwoven fabric without gaps. It is preferable that the surface of the non-woven heat-resistant fiber is substantially coated with particles of the perovskite complex oxide catalyst.
[0020] 耐熱性繊維表面上に担持されたべ口ブスカイト型複合酸化物触媒の粒子の層は、 少なくとも 1層、より好ましくは 2層以上である。  [0020] The layer of the particles of the open-bumskite complex oxide catalyst supported on the heat-resistant fiber surface is at least one layer, more preferably two or more layers.
耐熱性繊維表面上に担持された本発明のベロブスカイト型複合酸化物触媒の粒子 の粒子径は、担持前と同様であり、例えば、 0. 1〜： LOOnm、好ましくは、 0. 5 50n m、より好ましくは、 l 20nmである。  The particle size of the particles of the velovskite complex oxide catalyst of the present invention supported on the heat-resistant fiber surface is the same as that before the support, for example, 0.1 to: LOOnm, preferably 0.5 50 nm More preferably, l is 20 nm.
本発明のぺロブスカイト型複合酸化物触媒の粒子の層の厚さは、例えば、 0. 1 1 00 好ましくは、 l 50nm、より好ましくは、 20 50nmである。  The layer thickness of the particles of the perovskite complex oxide catalyst of the present invention is, for example, 0.1 1 00, preferably 50 nm, more preferably 20 50 nm.
[0021] (2)ディーゼルパティキュレートフィルタの製造方法 [0021] (2) Diesel particulate filter manufacturing method
本発明のディーゼルパティキュレートフィルタは、特定の粒径を有するぺロブスカイ ト型複合酸化物触媒を調製し、このべ口ブスカイト型複合酸化物触媒を不織布の耐 熱性繊維の表面に担持することにより製造される。  The diesel particulate filter of the present invention is produced by preparing a perovskite-type composite oxide catalyst having a specific particle size, and supporting this bottom-bskite-type composite oxide catalyst on the surface of a heat resistant fiber of a nonwoven fabric. Is done.
[0022] (2-1)ベロブスカイト型複合酸化物触媒の製法 [0022] (2-1) Method for producing a velovskite complex oxide catalyst
本発明のベロブスカイト型複合酸ィ匕物触媒は、いかなる公知の方法によって製造さ れてもよいが、以下に示すエチレングリコール法によって製造されることが適当である 具体的に、まず、 Kゝ Niゝ Srゝ Co、 Laゝ Cuゝ V、 Mn、 Feゝ Csゝ Baゝ Ceゝ Liゝ Pdなど の上記式 (I) : A B C O の A、 B及び Cを構成する元素の塩、好ましくは、硝酸塩、  The velovskite type complex oxide catalyst of the present invention may be produced by any known method, but is suitably produced by the ethylene glycol method shown below. Specifically, first, K ゝNi ゝ Sr ゝ Co, La ゝ Cu ゝ V, Mn, Fe ゝ Cs ゝ Ba ゝ Ce ゝ Li ゝ Pd and other formulas (I): Salts of elements constituting A, B and C of ABCO, preferably Nitrates,
P q r 3 硫酸塩又は塩酸塩を準備する。この塩を秤量し、塩の濃度が 1Mになるように常温で 液体のアルキレングリコール、例えば、エチレングリコール、プロピレングリコール、好 ましくはエチレングリコールのような溶媒に溶解し、得られた溶液を常温常圧下で 1〜 10時間、好ましくは 6時間程度撹拌する。 P qr 3 Prepare sulfate or hydrochloride. The salt is weighed and dissolved in a solvent such as alkylene glycol, such as ethylene glycol, propylene glycol, or preferably ethylene glycol, at room temperature so that the salt concentration is 1M. Stir at normal pressure for 1 to 10 hours, preferably about 6 hours.
[0023] 次いで、得られた溶液を、焼成用容器に移し、常圧下、常温から、毎分 0. 1〜10 。C、好ましくは毎分 0. 5〜5°Cの速度で 100〜200°C、好ましくは 200°Cまで昇温し 、溶媒を完全に除去する。その後、さらに毎分 5〜30°C、好ましくは、毎分 10〜20°C の速度で、 400〜800°C、好ましくは 600°Cまで昇温した後、さらに、昇温後の温度 を維持しながら、例えば、 1〜10時間、好ましくは、 5時間程度残留物を焼成し、触媒 のぺロブスカイト構造を固定ィ匕する。ここで、上記昇温'焼成工程は、ぺロブスカイト 構造とするために、焼成用容器内に酸素又は空気を、 0. 5リットル Z分以上、好まし くは、 1リットル Z分以上の流量で送りながら行う。 [0023] Next, the obtained solution is transferred to a baking container, and it is 0.1 to 10 per minute from normal temperature under normal pressure. C, preferably at a rate of 0.5 to 5 ° C per minute and heated to 100 to 200 ° C, preferably 200 ° C, to completely remove the solvent. Thereafter, the temperature is further increased to 400 ° C to 800 ° C, preferably 600 ° C at a rate of 5 to 30 ° C per minute, preferably 10 to 20 ° C per minute. While maintaining, for example, the residue is calcined for 1 to 10 hours, preferably about 5 hours, to fix the perovskite structure of the catalyst. Here, in order to obtain a perovskite structure in the above temperature rising and firing step, oxygen or air is introduced into the firing container at a flow rate of 0.5 liter Z minutes or more, preferably 1 liter Z minutes or more. Do it while sending.
[0024] 得られた焼成物は、室温に冷却後粉砕され、目的の粒子径を有するぺロブスカイト 型複合酸化物触媒の粒子を得る。ここで、粉砕は、乳鉢を用いて、例えば、 50gの触 媒粒子であればこれを 20当分し、合計 1〜6時間、好ましくは 4時間程度かけて開砕 することが適当である。 [0024] The obtained fired product is cooled to room temperature and then pulverized to obtain particles of a perovskite complex oxide catalyst having a target particle size. Here, it is appropriate that the pulverization is performed using a mortar, for example, if it is 50 g of catalyst particles, 20 minutes, and crushing for a total of 1 to 6 hours, preferably about 4 hours.
[0025] (2-2)不織布の耐熱性繊維の表面上へのぺロブスカイト型複合酸化物触媒の担持 方法  [0025] (2-2) Method for supporting perovskite complex oxide catalyst on the surface of heat-resistant fiber of nonwoven fabric
本発明のディーゼルパティキュレートフィルタは、例えば、以下の工程に従って製 造され得る。  The diesel particulate filter of the present invention can be manufactured, for example, according to the following steps.
(1)本発明のぺロブスカイト型複合酸ィ匕物触媒の粒子をアルコール性水溶液中に懸 濁した懸濁液中に本発明の不織布を浸漬する工程、  (1) a step of immersing the nonwoven fabric of the present invention in a suspension in which the particles of the perovskite type composite oxide catalyst of the present invention are suspended in an alcoholic aqueous solution;
(2)不織布を負極とし、懸濁液中の正極と負極との間に電位差を与え、本発明の不織 布の耐熱性導電性繊維表面上に上記触媒の粒子を付着させる工程、及び  (2) using a nonwoven fabric as a negative electrode, applying a potential difference between the positive electrode and the negative electrode in the suspension, and attaching the catalyst particles onto the heat-resistant conductive fiber surface of the nonwoven fabric of the present invention; and
(3)耐熱性導電性繊維表面上に上記触媒の粒子が付着した本発明の不織布を懸濁 液から取り出し、不織布を焼結する工程。  (3) A step of removing the nonwoven fabric of the present invention in which the catalyst particles are adhered on the surface of the heat-resistant conductive fiber from the suspension and sintering the nonwoven fabric.
以下、各工程について詳説する。  Hereinafter, each step will be described in detail.
(2-2-1)本発明のぺロブスカイト型複合酸化物触媒の粒子をアルコール性水溶液中 に懸濁した懸濁液中に本発明の不織布を浸漬する工程 (2-2-1) Particles of the perovskite complex oxide catalyst of the present invention in an alcoholic aqueous solution Step of immersing the nonwoven fabric of the present invention in the suspension suspended in
まず、本発明のぺロブスカイト型複合酸化物触媒の粒子は、アルコール性水溶液 中に懸濁される。ここで、アルコール性水溶液は、常温 (25°C)で液状のアルコールと 水を含む。アルコールとしては、炭素数 1〜3のアルコール、例えば、メタノール、エタ ノール、 n-プロパノール、イソプロパノールが挙げられる。好ましくは、エタノールであ る。アルコールは、アルコール性水溶液全体の体積に対して、例えば、 85〜99%、 好ましくは、 92〜97%含まれる。  First, the particles of the perovskite complex oxide catalyst of the present invention are suspended in an alcoholic aqueous solution. Here, the alcoholic aqueous solution contains alcohol and water which are liquid at room temperature (25 ° C). Examples of the alcohol include alcohols having 1 to 3 carbon atoms such as methanol, ethanol, n-propanol, and isopropanol. Ethanol is preferable. Alcohol is contained, for example, 85 to 99%, preferably 92 to 97%, based on the total volume of the alcoholic aqueous solution.
水は、例えば、イオン交換水を使用することができる。また、水は、アルコール性水 溶液全体の体積に対して、例えば、 1〜15%、好ましくは、 3〜8%含まれる。  For example, ion-exchanged water can be used as the water. Further, water is contained, for example, in an amount of 1 to 15%, preferably 3 to 8%, based on the total volume of the alcoholic aqueous solution.
さらに、アルコール性水溶液には、分散剤としてアルコールに溶解するァ-オン系 の界面活性剤を含めてもよい。分散剤は、本発明のベロブスカイト型複合酸化物触 媒の質量に対して 0. 2〜0. 6質量％、好ましくは、 0. 4〜0. 5質量％含まれてもよ い。  Furthermore, the alcoholic aqueous solution may contain a ionic surfactant that dissolves in alcohol as a dispersant. The dispersant may be contained in an amount of 0.2 to 0.6% by mass, preferably 0.4 to 0.5% by mass, based on the mass of the velovskite complex oxide catalyst of the present invention.
懸濁液は、アルコール性水溶液 1リットル中、本発明のぺロブスカイト型複合酸化物 触媒の粒子を、例えば、 5〜50g、好ましくは、 10〜30g含むことが適当である。 (2-2-2)不織布を負極とし、懸濁液中の正極と負極との間に電位差を与え、本発明 の不織布の耐熱性導電性繊維表面上に上記触媒の粒子を付着させる工程  The suspension suitably contains, for example, 5 to 50 g, preferably 10 to 30 g of the perovskite complex oxide catalyst particles of the present invention in 1 liter of an alcoholic aqueous solution. (2-2-2) A step in which the nonwoven fabric is used as a negative electrode, a potential difference is applied between the positive electrode and the negative electrode in the suspension, and the catalyst particles are adhered on the heat-resistant conductive fiber surface of the nonwoven fabric of the present invention.
次いで、懸濁液中に電位差を与え、いわゆる電気泳動を利用して、本発明の不織 布の耐熱性導電性繊維表面上に本発明の触媒粒子を付着させる。上記懸濁液中に は、本発明のぺロブスカイト型複合酸化物触媒の粒子が分散している。この粒子のま わりには、水力 分離した水素イオンが付着しており、懸濁液中で正に帯電している 。従って、不織布を負極として懸濁液中の正極及び負極に電位差を与えることにより 、正に帯電した触媒粒子が負極である不織布の耐熱性繊維表面上に集まり、静電工 ネルギーによって付着する。  Next, a potential difference is applied to the suspension, and the catalyst particles of the present invention are adhered to the surface of the heat-resistant conductive fibers of the nonwoven fabric of the present invention using so-called electrophoresis. In the suspension, particles of the perovskite complex oxide catalyst of the present invention are dispersed. Around these particles, hydrogen ions separated by hydraulic force are attached and are positively charged in the suspension. Therefore, by applying a potential difference between the positive electrode and the negative electrode in the suspension using the nonwoven fabric as the negative electrode, the positively charged catalyst particles gather on the surface of the heat-resistant fiber of the nonwoven fabric, which is the negative electrode, and adhere by electrostatic energy.
ここで、正極としては、例えば、炭素電極、 CZC (カーボンコンポジット)が使用でき る。負極としては、本発明の不織布、好ましくは本発明の不織布を挟持した金網、例 えば、ステンレス製金網 (孔径 0. 5〜5mm、好ましくは l〜3mm、 目開き 5〜50mm 、好ましくは、 10〜30mm)を使用する。これらの正極と負極の間に電位差を与える。 電位差は、例えば、電圧： 50〜200V、好まし <は 100〜150V、電流： 100〜2000 mA、好ましくは 200〜1000mA、より好ましくは 200〜800mAで、 5〜30分、好ま しくは、 5〜20分与える。 Here, as the positive electrode, for example, a carbon electrode or CZC (carbon composite) can be used. As the negative electrode, a non-woven fabric of the present invention, preferably a metal mesh sandwiching the non-woven fabric of the present invention, for example, a stainless steel mesh (pore diameter 0.5 to 5 mm, preferably 1 to 3 mm, opening 5 to 50 mm, preferably 10 ~ 30mm). A potential difference is applied between the positive electrode and the negative electrode. The potential difference is, for example, voltage: 50 to 200V, preferably <100 to 150V, current: 100 to 2000 mA, preferably 200 to 1000 mA, more preferably 200 to 800 mA, 5 to 30 minutes, preferably 5 Give ~ 20 minutes.
[0027] (2-2-3)耐熱性導電性繊維表面上に上記触媒の粒子が付着した本発明の不織布を 懸濁液から取り出し、不織布を焼結する工程  (2-2-3) A step of taking out the nonwoven fabric of the present invention in which the catalyst particles are adhered on the surface of the heat-resistant conductive fiber from the suspension and sintering the nonwoven fabric.
耐熱性導電性繊維表面上に上記触媒の粒子が付着した本発明の不織布は、上記 電気泳動の後、懸濁液から取り出される。その後、常温でアルコール性水溶液を、例 えば 1〜10時間、好ましくは 5時間程度自然乾燥して不織布力も懸濁液を除去する。 さらに不織布を焼結して耐熱性導電性繊維表面上に上記触媒の粒子を担持する。 焼結は、例えば、電気炉などを用い、例えば、 400〜1000°C、好ましくは、 600〜9 00°C、より好ましくは 800°Cで 1〜5時間、好ましくは、 1. 5〜3時間、より好ましくは、 2時間行う。このようにして耐熱性導電性繊維表面上に担持された上記触媒の粒子 は、担持の前後で粒子の大きさや構造に変化はない。  The nonwoven fabric of the present invention in which the catalyst particles adhere to the surface of the heat-resistant conductive fiber is taken out of the suspension after the electrophoresis. Thereafter, the aqueous alcoholic solution is naturally dried at room temperature, for example, for 1 to 10 hours, preferably for about 5 hours, and the suspension is also removed. Further, the nonwoven fabric is sintered to carry the catalyst particles on the surface of the heat-resistant conductive fiber. Sintering uses, for example, an electric furnace or the like, for example, 400 to 1000 ° C, preferably 600 to 900 ° C, more preferably 800 ° C for 1 to 5 hours, preferably 1.5 to 3 For 2 hours, more preferably 2 hours. The catalyst particles supported on the heat-resistant conductive fiber surface in this way have no change in the size or structure of the particles before and after the support.
[0028] (3)ディーゼルエンジン排ガス用の浄化装置  [0028] (3) Diesel engine exhaust gas purification device
本発明のディーゼルパティキュレートフィルタは、ディーゼルエンジン排ガス用の浄 化装置に使用される。具体的には、ディーゼルエンジン排ガス用の浄ィ匕装置は、ディ ーゼルエンジンの燃焼室の後方であって排ガスを大気中に放出する排出口の手前 に取り付けられる。ディーゼルエンジン排ガス用の浄ィ匕装置は、本発明のディーゼル パティキュレートフィルタを含む。排ガスは、浄化装置に導入され、浄化装置内のディ ーゼルパティキュレートフィルタを通過した後に、浄ィ匕装置外に放出される。ディーゼ ルパティキュレートフィルタを通過する際に、排ガスに含まれる粒子状物質 (PM)及び 窒素酸ィ匕物 (NOx)を捕捉し、ディーゼルパティキュレートフィルタに含まれる耐熱性 繊維の間隙 (孔)に堆積する。堆積した粒子状物質 (PM)及び窒素酸ィ匕物 (NOx)は、 耐熱性繊維の表面上に担持されたべ口ブスカイト型複合酸化物触媒上で反応し、 P Mの主成分であるカーボン Cと NOxの Oが酸化反応を行って COとなり、同時に NO  The diesel particulate filter of the present invention is used in a purification apparatus for diesel engine exhaust gas. Specifically, a diesel engine exhaust gas purifier is attached to the rear of the diesel engine combustion chamber and in front of the exhaust port for releasing the exhaust gas into the atmosphere. A diesel engine exhaust gas purification apparatus includes the diesel particulate filter of the present invention. The exhaust gas is introduced into the purification device, passes through a diesel particulate filter in the purification device, and then released to the outside of the purification device. When passing through the diesel particulate filter, particulate matter (PM) and nitrogen oxides (NOx) contained in the exhaust gas are trapped and put into the gaps (holes) of the heat-resistant fibers contained in the diesel particulate filter. accumulate. The deposited particulate matter (PM) and nitrogen oxides (NOx) react on the bottom bskite-type complex oxide catalyst supported on the surface of the heat-resistant fiber and react with carbon C, which is the main component of PM. NOx O undergoes oxidation reaction to become CO, and at the same time NO
2  2
Xは、 Nに還元されて無害化され、浄ィ匕装置を出て、上記排出口から大気中に放出 X is reduced to N, detoxified, exits the purifier, and is released into the atmosphere through the above outlet
2 2
される。  Is done.
c+o→co NO→N +0 c + o → co NO → N +0
x 2 2  x 2 2
(但し、係数は省略）  (However, coefficient is omitted)
なお、ディーゼルの燃焼反応の着火温度が低 、(250°C)場合、  When the ignition temperature of diesel combustion reaction is low (250 ° C),
2NO +C→2NO + CO  2NO + C → 2NO + CO
2 2  twenty two
のような反応も起こる。また、 NOxと炭化水素力 N、 CO及び水が生成する反応  Such a reaction also occurs. Also, the reaction of NOx and hydrocarbon power N, CO and water
2 2  twenty two
により NOxが分解することもあり、実際の反応の反応式はより複雑である。  NOx may be decomposed due to the fact that the reaction formula of the actual reaction is more complicated.
[0029] さらに、ディーゼルエンジンの特性上、車が走行して!/、るときなど、エンジンの回転 数が高ぐディーゼルエンジンの燃焼室での燃焼温度が高い場合は、排ガス中に N Oxが過多となり、車が停止しているときなど、エンジンの回転数が低ぐディーゼルェ ンジンの燃焼室での燃焼温度が低い場合は、 PM、つまり Cが過多となる。このような 場合にも、本発明のベロブスカイト型複合酸化物触媒は、良好に作用する。つまり、 NOx過多の下では、高温でイオン伝導性が良くなり、触媒の還元作用が活発になり 、窒素酸化物 NOxが良好に分解する。一方、 C過多の下でも、本発明のぺロブス力 イト型複合酸化物触媒は、低温活性能が高ぐ NOxと Cとの接触反応の活性ィ匕により 、 Cを良好に酸ィ匕することができる。 [0029] Furthermore, due to the characteristics of the diesel engine, if the combustion temperature in the combustion chamber of a diesel engine with a high engine speed is high, such as when the car is running! /, The NOx is contained in the exhaust gas. If the combustion temperature in the combustion chamber of a diesel engine with a low engine speed is low, such as when the car is stopped, the PM, that is, C will be excessive. Even in such a case, the velovskite complex oxide catalyst of the present invention works well. In other words, under excessive NOx, ionic conductivity is improved at high temperatures, the catalytic reduction action is activated, and nitrogen oxides NOx are decomposed well. On the other hand, even under excessive C, the perovskite-type composite oxide catalyst of the present invention can efficiently oxidize C due to the activity of the catalytic reaction between NOx and C, which has high low-temperature activity. Can do.
[0030] 本発明のディーゼルエンジン排ガス用の浄化装置内のディーゼルパティキュレート フィルタは、本発明のベロブスカイト型複合酸ィ匕物触媒を担持した耐熱性繊維の不 織布を 1層、あるいは、 2層以上積層したものであってもよい。特に、 目付の異なる複 数の不織布の層を使用することにより、粒径の異なる粒子状物質 (PM)を良好に補足 することが可能となる。例えば、浄ィ匕装置内に排ガスの流れの上流部力も順に以下 のような不織布層を設けた三層構造とすることが好ましい。 [0030] The diesel particulate filter in the purification apparatus for diesel engine exhaust gas of the present invention has one layer or two layers of a non-woven fabric of heat-resistant fiber carrying the velovskite type composite oxide catalyst of the present invention. It may be a laminate of more than one layer. In particular, by using a plurality of nonwoven fabric layers having different basis weights, it becomes possible to supplement particulate matter (PM) having different particle sizes well. For example, it is preferable to have a three-layer structure in which the upstream portion force of the exhaust gas flow is provided with the following nonwoven fabric layers in order in the purification apparatus.
[0031] 表 1
Figure imgf000014_0001
[0031] Table 1
Figure imgf000014_0001
[0032] より好ましくは、以下のような不織布層を設けた三層構造とすることが適当である。 [0032] More preferably, a three-layer structure provided with the following nonwoven fabric layer is appropriate.
表 2 繊維の直径 ( n 不織布の厚さ（mm) 不織布の目付（g 上流部不繳布層 10〜20 1〜3 200 ~ 500 Table 2 Fiber diameter (n Nonwoven fabric thickness ( mm ) Nonwoven fabric weight (g Upstream non-woven fabric layer 10 ~ 20 1 ~ 3 200 ~ 500
中流部不織布層 3〜 10 1〜3 200—500  Middle stream nonwoven fabric layer 3 ~ 10 1 ~ 3 200-500
下流部不織布層 3〜 10 ト 3 200—500 このように積層構造とした場合、不織布の積層体の厚さは、例えば、 5〜50mm、好 ましくは、 10〜30mmであることが適当である。  Downstream nonwoven fabric layer 3 to 10 to 3 200-500 In this case, the thickness of the nonwoven fabric laminate is, for example, 5 to 50 mm, and preferably 10 to 30 mm. is there.
また、これらの不織布層の間には、例えば、 l〜20mm、好ましくは、 3〜： LOmmの 空間層を設けてもよい。  Moreover, you may provide the space layer of 1-20 mm between these nonwoven fabric layers, for example, Preferably, 3-: LOmm.
[0033] さらに、本発明のディーゼルエンジン排ガス用の浄化装置内のディーゼルパティキ ュレートフィルタは、本発明のベロブスカイト型複合酸化物触媒を担持した耐熱性繊 維カゝらなる不織布を、 2枚の耐熱性金属板で挟持し、得られた積層物を蛇腹状に折 り曲げたものであってもよい。蛇腹状にすることより、排ガスの接触面積を大きくするこ とができ、粒子状物質 (PM)が不織布上に残存した時の圧力損失を防止し、浄ィ匕装 置をコンパクトにすることができる。  [0033] Further, the diesel particulate filter in the diesel engine exhaust gas purification apparatus of the present invention comprises a non-woven fabric made of a heat-resistant fiber carrying the bevelskite-type composite oxide catalyst of the present invention. The laminate may be sandwiched between a sheet of heat-resistant metal plates and the resulting laminate may be bent into a bellows shape. By making the bellows shape, the contact area of the exhaust gas can be increased, pressure loss when particulate matter (PM) remains on the nonwoven fabric can be prevented, and the purification equipment can be made compact. it can.
ここで、上記耐熱性金属板としては、例えば、ステンレス (SUS301及び SUS304 など)等が挙げられる。耐熱性金属板の厚さは、例えば、 l〜8mm、好ましくは、 2〜5 mmで to 。  Here, examples of the heat-resistant metal plate include stainless steel (such as SUS301 and SUS304). The thickness of the heat-resistant metal plate is, for example, 1 to 8 mm, preferably 2 to 5 mm.
[0034] さらに、本発明のディーゼルエンジン排ガス用の浄ィ匕装置は、不織布上に残存した 粒子状物質 (PM)によるディーゼルパティキュレートフィルタの目づまりを防止するた めのディーゼルパティキュレートフィルタ用加熱装置を含んでもよい。加熱温度は、使 用する耐熱性繊維や触媒の耐熱温度以下、例えば、炭化珪素繊維を使用する場合 や触媒として Mnを含むぺロブスカイト型複合酸化物触媒を使用する場合、 800°C以 下、より好ましくは、 600°C以下に設定することが適当である。加熱装置としては、マイ クロ波照射装置が好ましい。マイクロ波照射装置は、短時間で不織布を昇温すること ができ、かつ、温度コントロールが容易である。マイクロ波照射装置を使用する際、本 発明の耐熱性繊維としては、マイクロ波吸収材である炭化珪素繊維、珪素繊維を使 用する必要がある。  Furthermore, the diesel engine exhaust gas purification device of the present invention is a diesel particulate filter heating device for preventing clogging of the diesel particulate filter due to particulate matter (PM) remaining on the nonwoven fabric. May be included. Heating temperature is below the heat resistant temperature of the heat resistant fiber or catalyst used, for example, when using silicon carbide fiber or when using a perovskite complex oxide catalyst containing Mn as the catalyst, 800 ° C or less, More preferably, the temperature is set to 600 ° C or lower. As the heating device, a microwave irradiation device is preferable. The microwave irradiation device can raise the temperature of the nonwoven fabric in a short time and is easy to control the temperature. When using the microwave irradiation apparatus, it is necessary to use silicon carbide fiber or silicon fiber, which is a microwave absorber, as the heat-resistant fiber of the present invention.
実施例  Example
[0035] 以下、本発明の実施例について説明する。 [実施例 1] Hereinafter, examples of the present invention will be described. [Example 1]
硝酸ランタン 6水和物 90g、硝酸ストロンチウム 10g、硝酸コバルト 80gを秤量し、ェチ レンダリコール 500ml中に加え、溶解した。得られた溶液を、 6時間撹拌した後、焼成 用容器に移し、常圧下、毎分 1°Cの速度で室温から 200°Cまで昇温してエチレンダリ コールを気化'除去し、残留物を得た。その後、毎分 10°Cの速度で 200°C力も 600 °Cまで昇温し、さらに 600°Cに 5時間維持して残留物を焼成した。上記昇温及び焼 成の間、焼成用容器内に、 1リットル Z分の流量で空気を送り込んだ。その後、室温 に冷却し、乳鉢で粉砕し、触媒の粒子 50gを得た。得られた触媒粒子を X線解析に 力け、 La Sr CoOの組成比を有するぺロブスカイト構造になっていることを確認し  90 g of lanthanum nitrate hexahydrate, 10 g of strontium nitrate, and 80 g of cobalt nitrate were weighed and added to 500 ml of ethylene glycol and dissolved. The resulting solution was stirred for 6 hours and then transferred to a baking container. The temperature was raised from room temperature to 200 ° C at a rate of 1 ° C per minute under normal pressure to vaporize and remove ethylene glycol, and remove the residue. Obtained. Thereafter, the 200 ° C. force was also raised to 600 ° C. at a rate of 10 ° C. per minute, and the residue was fired by maintaining at 600 ° C. for 5 hours. During the above temperature rise and firing, air was fed into the firing container at a flow rate of 1 liter Z. Thereafter, the mixture was cooled to room temperature and pulverized in a mortar to obtain 50 g of catalyst particles. The obtained catalyst particles are used for X-ray analysis and confirmed to have a perovskite structure with a composition ratio of La Sr CoO.
0.8 0.2 3  0.8 0.2 3
た。また、得られた触媒粒子の平均粒子径は、走査型電子顕微鏡で測定して、約 10 nmであることがわかった。また、比表面積は、 JIS R1626に準拠する BET法で測 定し、 50m2/gであることがわかった。 It was. The average particle size of the obtained catalyst particles was about 10 nm as measured with a scanning electron microscope. The specific surface area was measured by the BET method according to JIS R1626 and found to be 50 m 2 / g.
ガラス容器内に、エタノール 2リットル及びイオン交換水 100mlを加え、さらに、上記 で得られたぺロブスカイト型複合酸ィ匕物触媒 30gを懸濁し、懸濁液とした。懸濁液は 、粒子の凝集を開砕するために、予めホモジナイザ (超音波洗浄器) (ブランソン製、 15 10 J-MT)を利用して、超音波で分散 '開砕した。この懸濁液中に、 1枚の平板型負極 と、この平板型負極の上部及び下部に水平かつ平行に設置した 2枚の平板型正極 を浸潰した。ここで、負極としては、炭化珪素繊維 (チラノ繊維 (登録商標)耐熱グレー ド ZM (Si-C-O-Zr 組成比 56 : 34: 9 : 1) )から成る不織布 (トスコ (株)製トスコセラミ ックファイバーフェルト) (縦 X横 X厚さ： 290 X 210 X I. 57mm)を、孔径 2mm、目開 き 20mmのステンレス製金網で挟持したものを使用した。使用する炭化珪素繊維は、 繊維の直径 10 /ζ πι、繊維長 40mm、引張強さ 3. 4GPa(JIS K-7023に従って測定)を 有し、また、不織布は、目付 380g/m2、力さ密度 0. 24g/cm3を有する。また、正極 として、炭素板 (縦 X横 X厚さ： 300 X 240 X 5mm)を 2枚使用した。これらの正極は、 上記負極の上部と下部に、それぞれ 15mmの間隔をおいて、負極と平行になるよう に設置した。これら正極及び負極に、 100V、 800mAの直流電圧を 15分間印加し、 炭化珪素繊維上にベロブスカイト型複合酸化物触媒の粒子を担持した。その後、不 織布を懸濁液から取り出し、 5時間室温で自然乾燥後、 800°Cで 2時間焼結した。得 られた不織布の炭化珪素繊維上には、不織布と触媒粒子全体の質量に対して、 1. 0質量％の触媒粒子が担持されていた。また、担持されている触媒粒子は、 X線解析 により、 La Sr CoOの組成を有するぺロブスカイト型構造の複合酸ィ匕物であることが In a glass container, 2 liters of ethanol and 100 ml of ion-exchanged water were added, and 30 g of the perovskite type complex oxide catalyst obtained above was suspended to obtain a suspension. The suspension was dispersed and crushed with ultrasonic waves in advance using a homogenizer (ultrasonic cleaner) (manufactured by Branson, 15 10 J-MT) in order to crush the aggregated particles. One flat plate negative electrode and two flat plate positive electrodes placed horizontally and parallel to the upper and lower portions of the flat plate negative electrode were immersed in this suspension. Here, as the negative electrode, a non-woven fabric made of silicon carbide fiber (Tyranno Fiber (registered trademark) heat-resistant grade ZM (Si-CO-Zr composition ratio 56: 34: 9: 1))) (Tosco Ceramic manufactured by Tosco Corporation) Fiber felt) (length x width x thickness: 290 x 210 x I. 57 mm) sandwiched between stainless steel wire meshes with a hole diameter of 2 mm and openings of 20 mm was used. The silicon carbide fiber used has a fiber diameter of 10 / ζ πι, a fiber length of 40 mm, a tensile strength of 3.4 GPa (measured in accordance with JIS K-7023), and the nonwoven fabric has a basis weight of 380 g / m 2 and a strength. It has a density of 0.24 g / cm 3 . In addition, two carbon plates (length X width X thickness: 300 X 240 X 5 mm) were used as the positive electrode. These positive electrodes were placed above and below the negative electrode so as to be parallel to the negative electrode with an interval of 15 mm. A DC voltage of 100 V and 800 mA was applied to the positive electrode and the negative electrode for 15 minutes, and particles of the velovskite complex oxide catalyst were supported on the silicon carbide fiber. Thereafter, the nonwoven fabric was taken out of the suspension, naturally dried at room temperature for 5 hours, and then sintered at 800 ° C. for 2 hours. Gain On the resulting non-woven silicon carbide fiber, 1.0% by mass of catalyst particles was supported with respect to the total mass of the non-woven fabric and the catalyst particles. In addition, the supported catalyst particles are perovskite type complex oxides having a composition of La Sr CoO by X-ray analysis.
08 0.2 3  08 0.2 3
確認された。  confirmed.
また、炭化珪素繊維表面上を走査型電子顕微鏡により観察すると、図 1に示すよう に、平均粒子径が 10nmの触媒粒子が隙間なぐ均一に、担持されていることが確認 された。  Further, when the surface of the silicon carbide fiber was observed with a scanning electron microscope, as shown in FIG. 1, it was confirmed that catalyst particles having an average particle diameter of 10 nm were uniformly supported without gaps.
本発明のベロブスカイト型複合酸化物触媒の粒子は多層構造をなし、層の厚さは、 走査型電子顕微鏡により測定したところ、約 50nmであった。  The particles of the velovskite complex oxide catalyst of the present invention have a multilayer structure, and the thickness of the layer was about 50 nm as measured by a scanning electron microscope.
[0037] [比較例 1] [0037] [Comparative Example 1]
懸濁液の成分として、エタノールの代わりにアセトンを使用した以外は、実施例 1と 同様に試験を行！ヽ、炭化珪素繊維上にベロブスカイト型複合酸化物触媒の粒子を 担持した。得られた不織布の炭化珪素繊維上には、不織布と触媒粒子全体の質量 に対して、 7. 0質量％の触媒粒子が担持されていた。  Test as in Example 1 except that acetone was used instead of ethanol as a suspension component! On the other hand, particles of a velovskite complex oxide catalyst were supported on silicon carbide fibers. On the obtained silicon carbide fibers of the nonwoven fabric, 7.0% by mass of catalyst particles was supported with respect to the mass of the nonwoven fabric and the entire catalyst particles.
炭化珪素繊維の表面上に形成された触媒層の X線解析により La Sr CoOの組成  Composition of La Sr CoO by X-ray analysis of catalyst layer formed on the surface of silicon carbide fiber
08 0.2 3 を有するベロブスカイト型構造の複合酸ィ匕物であることが確認された。  It was confirmed to be a complex acid oxide having a velovskite structure having 08 0.2 3.
また、炭化珪素繊維表面上を走査型電子顕微鏡により観察すると、図 2に示すよう に、炭化珪素繊維上には、 10〜50nmの大きさの粒子径で平均粒子径が 30nmの 触媒粒子が二次凝集し、より大きな 50〜300nmの凝集塊として存在していた。炭化 珪素繊維上に触媒粒子が不均質に担持されていた。また、触媒粒子同士、あるいは 、触媒粒子と炭化珪素繊維との接着が弱ぐ触媒粒子は容易に脱落し得る状態だつ た。  Further, when the surface of the silicon carbide fiber was observed with a scanning electron microscope, as shown in FIG. 2, two catalyst particles having a particle diameter of 10 to 50 nm and an average particle diameter of 30 nm were found on the silicon carbide fiber. It then agglomerated and existed as larger 50-300 nm agglomerates. The catalyst particles were heterogeneously supported on the silicon carbide fibers. Further, the catalyst particles, or the catalyst particles having weak adhesion between the catalyst particles and the silicon carbide fiber, can be easily removed.
[0038] [評価]  [0038] [Evaluation]
実施例 1及び比較例 1で得られたディーゼルパティキュレートフィルタの粒子状物 質 (PM)及び窒素酸ィ匕物 (NOx)の分解能力を評価した。評価は、ディーゼルェンジ ンカゝら放出される排ガスを模した試験ガスを準備し、この試験ガスを実施例 1及び比 較例 1で得られたディーゼルパティキュレートフィルタを充填した浄ィ匕装置に通じて、 フィルタを通過したガスの成分をガスクロマトグラフィで分析することにより行った。 試験ガスとして、 5%0 -0. 5%NO— Heの組成のガスを使用した。また、浄ィ匕装 The diesel particulate filters obtained in Example 1 and Comparative Example 1 were evaluated for their ability to decompose particulate matter (PM) and nitrogen oxides (NOx). The evaluation was conducted by preparing a test gas simulating the exhaust gas emitted from the diesel engine and passing this test gas to the purification equipment filled with the diesel particulate filter obtained in Example 1 and Comparative Example 1. The gas components that passed through the filter were analyzed by gas chromatography. As a test gas, a gas having a composition of 5% 0 -0.5% NO-He was used. In addition, purification
2  2
置は、内径 15mm、高さ 300mmのステンレス SUS304製円筒型反応管の上面及び 下面に排ガス導入口と排出口を設けたものを使用した。この反応管中に、直径 15m m、厚さ 1. 57mmの大きさのディーゼルパティキュレートフィルタを 3枚重ねて充填し 、排ガスがこの 3枚のディーゼルパティキュレートフィルタを通過するように設定した。 使用したディーゼルパティキュレートフィルタは、粒子状物質 (PM)がフィルタに捕集 された状態を再現するため、予めカーボンブラック (東海カーボン (株)製トーカブラッ ク # 8500 グレード 14nm (粒子径 14nm) )を、使用したディーゼルパティキュレート フィルタの質量に対して 6質量％付着させたものを使用した。  The equipment used was a stainless steel SUS304 cylindrical reaction tube with an inner diameter of 15 mm and a height of 300 mm, with an exhaust gas inlet and outlet on the upper and lower surfaces. In this reaction tube, three diesel particulate filters having a diameter of 15 mm and a thickness of 1.57 mm were stacked and filled, and the exhaust gas was set to pass through the three diesel particulate filters. The diesel particulate filter used was carbon black (Tokai Black # 8500 grade 14nm (particle size 14nm) manufactured by Tokai Carbon Co., Ltd.) in order to reproduce the state where particulate matter (PM) was collected by the filter. , 6% by mass was used with respect to the mass of the diesel particulate filter used.
[0039] 試験は、上記試験ガスを 40mlZ分の流速で浄ィ匕装置に流した後、ガスクロマトダラ フィ (島津製作所製)で、生成する CO、 CO、 N N Oを 15分間隔で分析した。試験 [0039] In the test, the test gas was passed through a purification apparatus at a flow rate of 40 mlZ, and then generated CO, CO, and N N O were analyzed at 15 minute intervals with a gas chromatograph (manufactured by Shimadzu Corporation). Examination
2 2、 2  2 2, 2
は、試験ガスの温度 (上記反応管の外側の温度)を、 200°Cから 700°Cまで 1°C/分 で昇温させて行った。  The test gas temperature (temperature outside the reaction tube) was increased from 200 ° C to 700 ° C at 1 ° C / min.
粒子状物質 (PM)の分解は、粒子状物質 (PM)、つまり炭素 Cが、以下の式、  The decomposition of particulate matter (PM) is based on the following formula:
c+o 2→co、  c + o 2 → co,
2  2
C+ 1/20→CO、或いは  C + 1/20 → CO or
2  2
2NO +C→2NO + CO  2NO + C → 2NO + CO
2 2  twenty two
により酸ィ匕されるので、試験ガス中の CO及び COの濃度が高くなれば、粒子状物  As the concentration of CO and CO in the test gas increases, particulate matter
2  2
質 (PM)の除去が良好に進行したと判断した。  It was judged that the removal of quality (PM) proceeded well.
また、窒素酸ィ匕物 (NO)の分解は、 NOが、以下の式、  In addition, decomposition of nitrogen oxides (NO), NO is the following formula,
2NO→N +0、及び  2NO → N +0, and
2 2  twenty two
4NO→2N O + O、  4NO → 2N O + O,
2 2  twenty two
その他、 NOxと炭化水素力 N、 CO及び水が生成する反応により分解されるの  In addition, it is decomposed by the reaction of NOx and hydrocarbon power N, CO and water.
2 2  twenty two
で、試験ガス中の N及び N Oの濃度が高くなれば、窒素酸ィ匕物 (NO)の分解が良好  If the concentration of N and N 2 O in the test gas is high, decomposition of nitrogen oxides (NO) is good
2 2  twenty two
に進行したと判断した。  Judged to have progressed.
実施例 1の試験結果をグラフ 1に、比較例 1の試験結果をグラフ 2に示す。  The test result of Example 1 is shown in Graph 1, and the test result of Comparative Example 1 is shown in Graph 2.
[0040] グラフ 1 [0040] Graph 1
Figure imgf000019_0001
Figure imgf000019_0001
試料ガスの温度 c  Sample gas temperature c
[0041] グラフ 2 [0041] Graph 2
¾g+o¾oo+/fsooooi-" ¾g + o¾oo + / fsooooi- "
Figure imgf000019_0002
Figure imgf000019_0002
試料ガスの温度 /¾  Sample gas temperature / ¾
[0042] グラフ 1及び 2に示される通り、試験ガス中の CO及び COの濃度について、実施例 1 は比較例 1よりも高い濃度を示している。また、グラフには示されていないが、実施例 1では、 COは発生していない (Oppm)—方、比較例では各温度領域で COが発生し ている (例えば、 485。Cで 290ppm、 500。Cで 375ppm、 515。Cで 298ppm)。従って 、実施例 1のディーゼルパティキュレートフィルタは、粒子状物質 (PM)の分解能力が 高ぐかつ、処理された炭素 Cは、完全に COとなり、大気中に放出できることがわか [0042] As shown in graphs 1 and 2, the concentration of CO and CO in the test gas was determined in Example 1. Indicates a higher concentration than Comparative Example 1. Further, although not shown in the graph, in Example 1, CO is not generated (Oppm) —in the comparative example, CO is generated in each temperature region (for example, 485. 290 ppm at C, 500. 375ppm for C, 515. 298ppm for C). Therefore, it can be seen that the diesel particulate filter of Example 1 has a high particulate matter (PM) decomposition capacity, and that the treated carbon C becomes completely CO and can be released into the atmosphere.
2  2
る。 The
また、試験ガス中の N及び N Oの濃度について、実施例 1は比較例 1よりも高い濃  In addition, regarding the concentration of N and N 2 O in the test gas, Example 1 has a higher concentration than that of Comparative Example 1.
2 2  twenty two
度を示している。また、 N及び N Oの発生が開始する温度は、実施例 1が 365°C付 Shows the degree. The temperature at which N and N O start to be generated is 365 ° C in Example 1.
2 2  twenty two
近であるのに対し、比較例 1は 410°C付近である。従って、実施例 1のディーゼルパ ティキュレートフィルタは、窒素酸ィ匕物 (NOx)の分解能力が高ぐかつ、試料ガスが比 較的低温の場合でも良好に窒素酸ィ匕物 (NOx)を分解することができることがわかる。 図面の簡単な説明 In contrast, Comparative Example 1 is around 410 ° C. Therefore, the diesel particulate filter of Example 1 has a high ability to decompose nitrogen oxides (NOx) and can effectively remove nitrogen oxides (NOx) even when the sample gas is at a relatively low temperature. It can be seen that it can be decomposed. Brief Description of Drawings
[図 1]実施例 1で得られたディーゼルパティキュレートフィルタの炭化珪素繊維表面上 の走査型電子顕微鏡写真である。 FIG. 1 is a scanning electron micrograph on the surface of silicon carbide fiber of the diesel particulate filter obtained in Example 1.
[図 2]比較例 1で得られたディーゼルパティキュレートフィルタの炭化珪素繊維表面上 の走査型電子顕微鏡写真である。  FIG. 2 is a scanning electron micrograph on the surface of silicon carbide fiber of the diesel particulate filter obtained in Comparative Example 1.

Claims

請求の範囲 The scope of the claims
[1] 耐熱性繊維からなる不織布と、該耐熱性繊維の表面に担持されたぺロブスカイト型 複合酸ィ匕物触媒とを含むディーゼルパティキュレートフィルタであって、前記複合酸 化物触媒が 0. 1〜： LOOnmの平均粒子径を有する粒子であることを特徴とするディー ゼルパティキュレートフィルタ。  [1] A diesel particulate filter comprising a nonwoven fabric composed of heat-resistant fibers and a perovskite-type composite oxide catalyst supported on the surface of the heat-resistant fibers, wherein the composite oxide catalyst is 0.1. ~: A diesel particulate filter characterized by being particles having an average particle size of LOOnm.
[2] 前記べ口ブスカイト型複合酸化物触媒が、式 (I)：  [2] The above-mentioned mouthbskite-type complex oxide catalyst has the formula (I):
A B C O (I)  A B C O (I)
P q r 3  P q r 3
(式中、 A、 B及び Cは、互いに同一でも異なっていてもよぐ K、 Ni、 Sr、 Co、 La、 C u、 V、 Mn、 Fe、 Cs、 Ba、 Ce、 Li, Pd力らなる群力ら選択され; p及び qは、 0. 5<p < 1、 0< q< 0. 5、 p + q= lを満たし、 rは、 0又は 1である）  (In the formula, A, B and C may be the same or different from each other. K, Ni, Sr, Co, La, Cu, V, Mn, Fe, Cs, Ba, Ce, Li, Pd force, etc. And p and q satisfy 0.5 <p <1, 0 <q <0.5, p + q = l, and r is 0 or 1)
で表される、請求項 1に記載のディーゼルパティキュレートフィルタ。  The diesel particulate filter according to claim 1, represented by:
[3] 前記ぺロブスカイト型複合酸化物触媒が、 La K CoO、 La Sr CoO又は La K [3] The perovskite complex oxide catalyst is La K CoO, La Sr CoO, or La K
0.9 0.1 3 0.8 0.2 3 0.75 0 0.9 0.1 3 0.8 0.2 3 0.75 0
MnOである、請求項 1に記載のディーゼルパティキュレートフィルタ。 The diesel particulate filter according to claim 1, wherein the diesel particulate filter is MnO.
.25 3  .25 3
[4] 前記ぺロブスカイト型複合酸ィ匕触媒の BET法で測定した比表面積が 10m2Zg以 上である、請求項 1〜3のいずれ力 1項に記載のディーゼルパティキュレートフィルタ [4] The diesel particulate filter according to any one of claims 1 to 3, wherein a specific surface area of the perovskite-type composite acid catalyst is measured by BET method is 10 m 2 Zg or more.
[5] 前記不織布が、厚さ 0. 3〜： L0mm、かつ、力さ密度 0. 05〜： L OgZcm3を有する、 請求項 1〜4のいずれ力 1項に記載のディーゼルパティキュレートフィルタ。 [5] The nonwoven fabric, thickness 0.1. 3 to: L0mm, and the force of density 0. 05～: having L OgZcm 3, diesel particulate filter according to any force one of claims 1 to 4.
[6] 請求項 1〜5のいずれか 1項に記載のディーゼルパティキュレートフィルタを用いた ディーゼルエンジン力 排出される排ガス用の浄ィ匕装置。 [6] Diesel engine power using the diesel particulate filter according to any one of claims 1 to 5. A purifier for exhaust gas discharged.
[7] 耐熱性導電性繊維からなる不織布と、該耐熱性導電性繊維の表面に担持された 0[7] Non-woven fabric made of heat-resistant conductive fiber and supported on the surface of the heat-resistant conductive fiber
. 1〜： LOOnmの平均粒子径を有するぺロブスカイト型複合酸化物触媒の粒子とを含 むディーゼルパティキュレートフィルタの製造方法であって、 1 to: a method for producing a diesel particulate filter comprising particles of a perovskite complex oxide catalyst having an average particle size of LOOnm,
(1)前記ぺロブスカイト型複合酸ィ匕物触媒の粒子をアルコール性水溶液中に懸濁し た懸濁液中に前記不織布を浸漬する工程、  (1) a step of immersing the nonwoven fabric in a suspension obtained by suspending particles of the perovskite-type composite oxide catalyst in an alcoholic aqueous solution;
(2)前記不織布を負極とし、前記懸濁液中の正極と前記負極との間に電位差を与え、 前記不織布の耐熱性導電性繊維表面上に前記粒子を付着させる工程、及び  (2) using the nonwoven fabric as a negative electrode, applying a potential difference between the positive electrode and the negative electrode in the suspension, and attaching the particles on the heat-resistant conductive fiber surface of the nonwoven fabric;
(3)前記耐熱性導電性繊維表面上に前記粒子が付着した前記不織布を前記懸濁液 から取り出し、前記不織布を焼結する工程、 (3) The non-woven fabric with the particles attached on the surface of the heat-resistant conductive fiber is the suspension. Removing the nonwoven fabric and sintering the nonwoven fabric,
を含む方法。 Including methods.
請求項 7に記載の製造方法によって得られる耐熱性導電性繊維力 なる不織布と、 該耐熱性導電性繊維の表面に担持された 0. 1〜 1 OOnmの平均粒子径を有するぺ 口ブスカイト型複合酸ィ匕物触媒とを含むディーゼルパティキュレートフィルタ。 A non-woven fabric having a heat-resistant conductive fiber strength obtained by the production method according to claim 7, and a paper bskite-type composite having an average particle diameter of 0.1 to 1 OOnm supported on the surface of the heat-resistant conductive fiber A diesel particulate filter comprising an acid catalyst.
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