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WO-2026092360-A1 - PARTICULATE FILTER

WO2026092360A1WO 2026092360 A1WO2026092360 A1WO 2026092360A1WO-2026092360-A1

Abstract

The present invention relates to a particulate filter, which comprises - a substrate comprising a plurality of porous walls extending longitudinally to form a plurality of parallel channels extending from an inlet end to an outlet end, wherein a quantity of the channels are inlet channels that are open at the inlet end and closed at the outlet end, and a quantity of channels are outlet channels that are closed at the inlet end and open at the outlet end, - a layer of inorganic particles loaded on surfaces of porous walls in the inlet channels and/or outlet channels, which comprises inorganic particles of plate-like crystals, wherein the inorganic particles of plate-like crystals have an anti-agglomeration index (M) of at least 50% in water, and - optionally an in-wall TWC coating in the inlet channels and/or outlet channels. The present invention also relates to an exhaust treatment system comprising the particulate filter and a method for treating an exhaust stream using the same.

Inventors

  • CHEN, CHUN YU
  • WU, Ye Hui
  • GREMMINGER, Andreas
  • SCHMITZ, THOMAS

Assignees

  • BASF MOBILE EMISSIONS CATALYSTS LLC
  • BASF CATALYSTS (SHANGHAI) CO., LTD.

Dates

Publication Date
20260507
Application Date
20251027
Priority Date
20241028

Claims (20)

  1. A particulate filter, which comprises -a substrate, comprising a plurality of porous walls extending longitudinally to form a plurality of parallel channels extending from an inlet end to an outlet end, wherein a quantity of the channels are inlet channels that are open at the inlet end and closed at the outlet end, and a quantity of channels are outlet channels that are closed at the inlet end and open at the outlet end, -a layer of inorganic particles loaded on surfaces of porous walls in the inlet channels and/or outlet channels, which comprises inorganic particles of plate-like crystals, wherein the inorganic particles of plate-like crystals have an anti-agglomeration index (M) of at least 50%in water, as determined by subjecting a sample of the inorganic particles of plate-like crystals to dispersing in water, separating and collecting dispersed inorganic particles and undispersed inorganic particles, and calculating in accordance with the following equation, in which M represents the anti-agglomeration index, W 1 represents initial weight of the sample, W 2 represents weight of dispersed inorganic particles, P 1 represents initial particle size D 50 of the sample, and P 2 represents particle size D 50 of a mixture of the dispersed inorganic particles and the undispersed inorganic particles after collecting and drying, and -optionally, an in-wall TWC coating in the inlet channels and/or outlet channels.
  2. The particulate filter according to claim 1, which does not comprise the in-wall TWC coating.
  3. The particulate filter according to claim 1, which comprises the in-wall TWC coating in the inlet channels and/or outlet channels.
  4. The particulate filter according to any of preceding claims, wherein the inorganic particles of plate-like crystals have an anti-agglomeration index of at least 70%, more preferably 80%, most preferably 90%, in water.
  5. The particulate filter according to any of preceding claims, wherein the layer of inorganic particles substantially consists of the inorganic particles of plate-like crystals.
  6. The particulate filter according to any of preceding claims, wherein the inorganic particles, particularly the inorganic particles of plate-like crystals, are particles of a non-PGM inorganic material, particularly selected from alumina, hydrated alumina, boehmite, zirconia, ceria, silica, titania, magnesium oxide, zinc oxide, zinc carbonate, calcium oxide, calcium carbonate, silicate zeolite, aluminosilicate zeolite, or any combinations thereof.
  7. The particulate filter according to claim 6, wherein the non-PGM inorganic material is selected from alumina, hydrated alumina, boehmite, silica, zinc oxide, zirconia, or any combinations thereof, preferably alumina, boehmite or a combination thereof.
  8. The particulate filter according to any of preceding claims, wherein the plate-like crystals have an average crystal diameter of no more than 20 μm, no more than 10 μm, no more than 5 μm, or no more than 3 μm, as measured by a scanning electron microscope (SEM) .
  9. The particulate filter according to any of preceding claims, wherein the plate-like crystals have an average crystal thickness of no more than 1000 nm, no more than 500 nm, or no more than 300 nm, as measured by a scanning electron microscope (SEM) .
  10. The particulate filter according to any of preceding claims, wherein the plate-like crystals have an aspect ratio of at least 3, for example at least 5, and no more than 100, for example no more than 50, no more than 30, no more than 20, or no more than 15.
  11. The particulate filter according to any of preceding claims, which comprises the layer of inorganic particles at a loading of from 1 to 500 g/L or from 2 to 300 g/L.
  12. The particulate filter according to any of preceding claims 1, 2 and 4 to 10, which comprises the layer of inorganic particles at a loading of from 1 to 200 g/L, from 2 to 100 g/L, from 3 to 50 g/L, or from 10 to 40 g/L.
  13. The particulate filter according to any of preceding claims 1 and 3 to 10, which comprises the layer of inorganic particles at a loading of from 1 to 500 g/L, from 2 to 200 g/L, from 5 to 100 g/L, or from 10 to 60 g/L.
  14. The particulate filter according to any of preceding claims, wherein the in-wall TWC coating is in form of a washcoat comprising a TWC composition, preferably comprising a rhodium component and a platinum component which are supported on support particles selected from refractory metal oxides, oxygen storage components and any combinations thereof, more preferably being free or substantially free of a palladium component.
  15. The particulate filter according to any of preceding claims, which is a gasoline particulate filter.
  16. A method for producing a particulate filter as defined in any of claims 1 to 15, which includes -providing a substrate comprising a plurality of porous walls extending longitudinally to form a plurality of parallel channels extending from an inlet end to an outlet end, wherein a quantity of the channels are inlet channels that are open at the inlet end and closed at the outlet end, and a quantity of channels are outlet channels that are closed at the inlet end and open at the outlet end, -optionally, applying a TWC coating in the porous walls in the inlet and/or outlet channels of the substrate, -applying inorganic particles or precursors thereof on surfaces of porous walls in the inlet channels and/or outlet channels, wherein at least part of the inorganic particles or precursors thereof are particles of plate-like crystals, wherein the inorganic particles of plate-like crystals have an anti-agglomeration index (M) of at least 50%in water, as determined by subjecting a sample of the inorganic particles of plate-like crystals to dispersing in water, separating and collecting dispersed inorganic particles and undispersed inorganic particles, and calculating in accordance with the following equation, in which M represents the anti-agglomeration index, W 1 represents initial weight of the sample, W 2 represents weight of dispersed inorganic particles, P 1 represents initial particle size D 50 of the sample, and P 2 represents particle size D 50 of a mixture of the dispersed inorganic particles and the undispersed inorganic particles after collecting and drying, and -optionally, drying and/or calcining.
  17. The method according to claim 16, wherein the inorganic particles are applied by a dry coating or washcoating process, preferably by a dry coating process.
  18. The method according to claim 16 or 17, wherein the in-wall TWC coating is applied before applying the inorganic particles on surfaces of the porous walls.
  19. An exhaust treatment system, which comprises a particulate filter according to any of claims 1 to 15 or a particulate filter obtainable or obtained from the method according to any of claims 16 to 18, and is located downstream of a gasoline engine.
  20. A method for treating an exhaust stream from a gasoline engine, which includes contacting the exhaust stream with a particulate filter according to any of claims 1 to 15, a particulate filter obtainable or obtained from the method according to any of claims 16 to 18, or an exhaust treatment system as defined in claim 19.

Description

PARTICULATE FILTER FIELD OF THE INVENTION The present invention relates to a particulate filter, particularly a particulate filter for treatment of an exhaust stream from an internal combustion engine, which comprises an inorganic powder particle coating. The present invention also relates to an exhaust treatment system comprising the particulate filter and a method for treating an exhaust stream, particularly from an internal combustion engine. BACKGROUND OF THE INVENTION Engine exhaust substantially consists of gaseous pollutants such as unburned hydrocarbons (HC) , carbon monoxide (CO) and nitrogen oxides (NOx) , and particulate matter (PM) . For gasoline engines, three-way conversion catalysts (hereinafter interchangeably referred to as TWC catalyst or TWC) for gaseous pollutants and filters for particulate matter (PM) are well-known exhaust treatment means to ensure the exhaust emission to meet emission regulations, such as including Euro 6 standards and China 6 standards. In contrast to particulates generated by diesel lean burning engines, particulates generated by gasoline engines, such as gasoline direct-injection engines, tend to be finer and in lesser quantities. This is due to different combustion conditions of gasoline engines as compared to diesel engines. Also, hydrocarbon components are different in the emissions of gasoline engines as compared to diesel engines. Particulate filters specific for gasoline engines have been developed for a few decades in order to effectively treating the engine exhausts from gasoline engines. For example, WO 2020/219376A1 describes a catalyzed particulate filter which comprises (1) a gasoline particulate filter (GPF) , (2) a major catalytic layer coated onto or within an inlet side, an outlet side, or both sides of the GPF surfaces, the major catalytic layer comprising a first composition which comprises a first support material and a first platinum group metal (PGM) , and (3) a minor functional material layer placed onto or within an inlet side, an outlet side, or both sides of the GPF surfaces, the minor catalytic layer comprising a second composition; wherein the major catalytic layer has a higher loading than the minor functional material layer, the minor functional material layer is placed on top of the major catalytic layer, or the major catalytic material layer is placed on top of the minor functional layer. The catalyzed particulate filter provides an improved catalytic efficiency in conjunction with an efficient filter. WO2021/096841A1 describes a particulate filter for exhaust gas treatment from an internal combustion engine comprising (1) a particulate filter, the filter having an inlet side and an outlet side; (2) a functional material layer coated onto the inlet side, the outlet side, or both sides of the particulate filter. The functional material layer comprises (1) a first inorganic material comprises one or more of alumina, zirconia, ceria, silica, titania, a rare earth metal oxide other than ceria; and (2) a second inorganic material comprises one or more of alumina, zirconia, ceria, silica, titania, magnesium oxide, zinc oxide, manganese oxide, silicate zeolite, aluminosilicate zeolite. WO2023/237052A1 describes a particulate filter, which comprises a substrate comprising a plurality of porous walls extending longitudinally to form a plurality of parallel channels extending from an inlet end to an outlet end, wherein a quantity of the channels are inlet channels that are open at the inlet end and closed at the outlet end, and a quantity of channels are outlet channels that are closed at the inlet end and open at the outlet end; and a layer of inorganic particles loaded on surfaces of porous walls in the inlet channels and/or outlet channels, wherein the inorganic particles comprise or consist of boehmite particles. Typically, the exhaust from a gasoline engine contains a large amount of water vapor originating from fuel combustion. The water vapor may potentially undergo condensation and become liquid water, which will make gasoline particulate filters, particular those having a layer of inorganic particles, suffer from serious deterioration of filtration efficiency. Original equipment manufacturers (OEMs) , i.e. the vehicle manufacturers, require gasoline particulate filters (GPFs) to have a high filtration efficiency at a Iow back pressure after water treatment, to avoid failure of particulate emission treatment due to existence of condensed water. It is known that filtration performance of a gasoline particulate filter will improve over the lifetime of the filter, primarily as a result of ash and soot accumulation on the walls of the inlet sides in the filter. Also, it was identified that particulate number of an emission generated during the cold start phase of a test cycle represents the primary portion of the total particles emitted during the test. Therefore, the particle filtration performance at the initial filtration phase, also ca