Particulate filter

Abstract

A method of treating a used particulate filter includes removing particulates from the particulate filter and introducing simulated ash into an inlet passage of the particulate filter after the particulates are removed.

Description

[0001] Cross-references to related applications

[0002] This application claims priority to International Application No. PCT / CN2020 / 139020, filed on December 24, 2020. Technical Field

[0003] The present invention generally relates to a particulate filter for removing particulate matter from sources including but not limited to engine emissions, and more specifically, to a method and system for treating a particulate filter during the manufacture and / or maintenance of the particulate filter. Background Technology

[0004] Particulate matter (PM) consists of fine solids or liquids, such as dust, fly ash, soot, smoke, aerosols, flue gas, mist, and condensate vapors that can remain suspended in the air for extended periods. Particulate matter originates from various stationary and mobile sources and can be directly emitted (primary PM sources) or formed into the atmosphere through gaseous emissions (secondary PM sources).

[0005] Primary PM sources originate from both human and natural activities. A significant portion of PM sources stems from various human activities. These activities include agricultural operations, industrial processing, the burning of timber and fossil fuels, construction and demolition activities, and the release of road dust into the air. Natural (non-anthropogenic or non-biological) sources also contribute to the overall PM problem. These include windblown dust and wildfires.

[0006] Secondary PM sources directly release air pollutants into the atmosphere, which either form or contribute to the formation of particulate matter. Therefore, these pollutants are considered precursors to particulate matter formation. These secondary pollutants include SO2. x NO x VOCs and ammonia. Control measures to reduce PM precursor emissions tend to have a positive impact on environmental PM levels.

[0007] For example, emissions from internal combustion engines consist of three phases: solids, liquids, and gases. The solids and liquids combined are called particles, particulate matter (PM), or total particulate matter (TPM), and mainly include dry carbon (smoke), inorganic oxides (such as sulfates), or organic liquids.

[0008] Particulate filters are known for removing particulate matter produced by, but not limited to, internal combustion engines, such as lean-burn engines, diesel engines, natural gas engines, gasoline engines, power plants, incinerators, or generator sets. It is also known in the art that particulate filters can take the form of flow-through filters, wall-flow filters (WFF), etc. A well-known type of particulate filter is the diesel particulate filter (DPF), which physically captures diesel particles to prevent their release into the atmosphere. Diesel particulate filter materials have been developed, exhibiting impressive filtration efficiency, as well as good mechanical and thermal durability. Diesel particulate filters have become the most effective technology for controlling diesel particulate emissions.

[0009] Due to the particulate deposition mechanisms in these devices, filters are most effective at controlling the solid portion of diesel particulates, including elemental carbon (soot) and associated black smoke emissions. Filters are less effective, or completely ineffective, at controlling the non-solid portion of PM emissions, such as the organic fraction (OF) and sulfate particles. To control total PM emissions, DPF systems may incorporate additional functional components targeting the organic fraction, typically an oxidation catalyst, while ultra-low sulfur fuels may require control of sulfate particles.

[0010] The term "diesel particulate trap" is sometimes used as a synonym for "diesel particulate filter," especially in earlier literature. The term "trap" encompasses a broader class of particulate separation devices.

[0011] It should be noted that particulate oxidation catalysts (POCs), sometimes referred to as partial filters, can also capture diesel particulates, but provide a much lower overall efficiency than diesel particulate filters. In their typical design, POCs capture particles only from a portion of the flow. However, in the case of some filter media, the distinction may not be clear, and these devices may be classified as either POCs or (depth) particulate filters.

[0012] Due to the low bulk density of diesel particles (typically around 0.1 g / cm³), 3 Depending on the tightness, diesel particulate filters can rapidly accumulate large amounts of soot. Significant amounts of soot are collected daily from older, heavy-duty engines. The collected particles eventually lead to excessively high exhaust pressure drop in the filter, negatively impacting engine operation. Therefore, diesel particulate filter systems must provide a method to remove particles from the filter to restore its soot-collecting capacity. This particulate removal, known as filter regeneration, can be performed continuously during normal filter operation or periodically after a predetermined amount of soot has accumulated. Thermal regeneration of the diesel particulate filter is typically employed, where the collected particles are oxidized by oxygen and / or nitrogen dioxide into gaseous products, primarily carbon dioxide.

[0013] To ensure particles are oxidized at a sufficient rate, the filter must operate at a sufficient temperature. In some filter systems, the heat source is the exhaust flow itself. In this type of filter system, known as a passive filter, the filter is continuously regenerated during normal engine operation. Passive filters typically contain some form of catalyst that lowers the soot oxidation temperature to levels achievable in the exhaust during vehicle operation. Another approach that may facilitate reliable regeneration includes numerous active strategies for increasing filter temperature (engine management, fuel combustion in the exhaust system, electric heaters, etc.). Regeneration of this device, known as an active filter or pseudo-active filter, is typically performed periodically, determined by the vehicle's control system.

[0014] Another strategy is to use disposable filter cartridges, which are replaced with new cartridges once they are full of soot. This type of particulate filter is used in some occupational health environments.

[0015] A gasoline particulate filter (GPF) is an emissions aftertreatment technology, similar to a diesel particulate filter (DPF), developed to control particulate emissions from gasoline engines, particularly gasoline direct injection (GDI) engines. This technology is also known as a gasoline particulate filter (PPF), and in some German literature, it is referred to as the Otto particulate filter (German: Ottopartikelfilter), abbreviated as OPF.

[0016] The GPF is expected to be used primarily in Europe and China to meet the particulate number (PN) emission standards for gasoline passenger cars and light commercial vehicles adopted in these two jurisdictions. The Euro 6 regulation sets PN (and PM) limits equivalent to those for diesel vehicles for GDI vehicles. China's PN standard is not limited to GDI vehicles but applies to all gasoline vehicles.

[0017] GPF can also be used in some port fuel injection (PFI) engines, even if PFI vehicles do not meet the European PN / PM emission standards.

[0018] Most early GPF applications involved uncoated GPF located downstream of a TWC catalyst. As the technology matured, GPFs were also coated with three-way catalysts. This catalyst-coated GPF configuration is sometimes referred to as a four-way catalyst (FWC).

[0019] Although GPF and DPF technologies are closely related, there are many differences in filter configuration, operation, and control strategies due to differences in operating conditions, particulate emission rates, and composition between gasoline and diesel engines.

[0020] After prolonged use, particulate matter accumulates in the filter's channels, adversely limiting its lifespan, increasing pressure drop, and impairing engine fuel economy. Therefore, regular cleaning of the particulate filter is necessary to remove particles accumulated in the channels. Currently, particulate cleaning is primarily performed at specified maintenance intervals or when an abnormally high pressure drop in the filter triggers a malfunction. For example, the U.S. Environmental Protection Agency has established a minimum particulate cleaning interval of 150,000 miles for heavy-duty highway vehicles. Summary of the Invention

[0021] On one hand, a method for processing a used particulate filter is disclosed, the method comprising: removing particles from the particulate filter; and introducing simulated ash into the inlet channel of the particulate filter after removing the particles.

[0022] This method can be used with virtually all types of commercially available filters designed to remove particulate matter from sources including, but not limited to, internal combustion engines such as lean-burn engines, diesel engines, natural gas engines, gasoline engines, power plants, incinerators, etc.

[0023] The filter can be configured as a wall-flow honeycomb filter, a fiber-wound filter or a fiber-filled filter, an open-cell foam filter, a sintered metal filter, a candle filter, etc., as is known in the art. The filter can be a canister filter comprising a filter media housed within a housing, or a non-canister filter comprising the filter media but excluding a housing for protecting the filter media, for example, until integrated into an emissions treatment system.

[0024] Filters are typically formed from a porous matrix. The porous matrix may include ceramic materials such as cordierite, silicon carbide, silicon nitride, zirconium oxide, mullite, spodumene, alumina-silica-magnesium oxide, zirconium silicate, and / or aluminum titanate, typically cordierite, silicon carbide, or any material known in the art. Filters advantageously include refractory materials such as cordierite, silicon carbide, or aluminum titanate.

[0025] This method is useful for processing used filters, which are filters that have already been used to perform their filtration functions. For example, this method can be used to process used filters that meet at least one of the following processing criteria: a specific time period since the particulate filter's last treatment, a specific mileage of the vehicle with the particulate filter, the regeneration frequency of the particulate filter within the specific time period, the horsepower of the vehicle with the particulate filter, warnings from indicator lights, signals from sensors, a specific back pressure of the particulate filter, a specific load of particulate matter, etc. For example, this method can be used to process used filters to meet more stringent or mandatory regulations.

[0026] In this method, the step of removing particles preferably includes applying a gas flow and / or a liquid flow at the outlet and / or inlet of the particle filter.

[0027] In one or more embodiments, the gas flow has a pressure of about 1-15 bar and / or a flow rate of about 100-10000 liters per minute.

[0028] In one or more embodiments, the gas stream includes, but is not limited to, oxygen, nitrogen, CO2, or a rare gas.

[0029] In one or more embodiments, the gas stream includes steam.

[0030] In one or more embodiments, the liquid flow has a pressure of about 0-15 bar and / or a flow rate of about 0-10000 liters per minute. In this method, the step of removing particles preferably includes exposing the particulate filter to a temperature up to about 450°C to 850°C.

[0031] In this method, the step of introducing simulated ash preferably includes introducing a stream of droplets and / or solid particles of simulated ash and / or its precursor into the channel of the particle filter through the inlet end of the particle filter. Advantageously, the flow rate of the droplets and / or solid particles is 100-10000 m³ / h. 3 / h. Advantageously, droplets and / or solid particle streams are introduced into the particle filter by means of blowing, suction, spraying and / or coating.

[0032] In this method, the step of introducing simulated ash preferably includes introducing simulated ash into the channels of the particulate filter, and optionally, further processing the particulate filter. In one embodiment, such processing includes exposing the particulate filter to thermal conditions, for example, not less than 300°C, more preferably not less than 350°C, and most preferably not less than 400°C.

[0033] In this method, the step of introducing simulated ash preferably includes introducing a precursor into the channel of a particulate filter and further processing the particulate filter to convert the precursor into simulated ash. In one embodiment, such processing includes exposing the particulate filter to thermal conditions, for example, not less than 300°C, more preferably not less than 350°C, and most preferably not less than 400°C.

[0034] In this method, the simulated ash and / or precursors are advantageously provided in an amount of not less than about 0.05 grams per liter of particulate filter volume.

[0035] In this method, the simulated ash has a porous structure and still exists at temperatures not lower than 300°C.

[0036] In this method, the simulated ash comprises at least one refractory material that resists significant decomposition caused by thermal, pressure, physical or chemical treatment of particles and other components in exhaust or flue gas or feed gas (e.g., hydrocarbons, CO, nitrogen oxides, O2, N2, CO2, H2O, etc.).

[0037] In this method, simulated ash can be introduced into the particulate filter as is and / or from the precursor.

[0038] In one embodiment, the precursor is a material that at least participates in the chemical reaction that produces the simulated ash.

[0039] In one embodiment, the precursor is a material that at least participates in the physical changes that produce the simulated ash.

[0040] In one embodiment, the precursor is a material that produces simulated ash under processing conditions. Processing conditions include, but are not limited to, temperature such as heating or cooling, light such as light, microwaves, radiation, electric fields, magnetic fields, electromagnetic fields, ultrasound, pressure, and mechanical strength.

[0041] In one embodiment, such treatment includes exposing the particulate filter to thermal conditions, such as not less than 300°C, more preferably not less than 350°C, and most preferably not less than 400°C.

[0042] In some embodiments, the simulated ash and / or precursors include, but are not limited to, one or more of the following: oxygen-containing compounds or oxygen-containing compounds, such as inorganic oxide compounds, metal oxides, non-metal oxides, composite oxides, mixed oxides, salts, sulfates, phosphates, carbonates, silicates, molecular sieves, hydroxides, organometallic compounds, etc.

[0043] In some embodiments, the simulated ash and / or precursors include alumina, aluminates, zinc oxide, zinc carbonate, calcium oxide, calcium carbonate, cerium-zirconium (mixed) oxides, zirconium oxide, cerium oxide, silicon dioxide, titanium dioxide, silicon-titanium (mixed) oxides, rare earth metal oxides other than cerium dioxide, magnesium oxide, barium oxide, barium sulfate, barium carbonate, hafnium oxide, manganese oxide, iron oxide, vanadium oxide, niobium oxide, chromium oxide, molybdenum oxide, tungsten oxide, cobalt oxide, nickel oxide, copper oxide, antimony oxide, alkali metal oxides, alkaline earth metal oxides, transition metal oxides, group metal oxides, molecular sieves, silicate zeolites, aluminosilicate zeolites, and non-zeolite molecular sieves.

[0044] In some embodiments, the simulated ash and / or precursors are derived from natural sources, including but not limited to lime, volcanic ash, refractory clay, or ceramics.

[0045] In some embodiments, the simulated ash and / or precursors are obtained from the processing or treatment of natural sources.

[0046] In some embodiments, the simulated ash and / or precursors include, but are not limited to, silicon carbide and carbon (graphite).

[0047] In some embodiments, the simulated ash and / or precursors include, but are not limited to, carbides, nitrides, binary compounds such as tungsten carbide, boron nitride, hafnium carbide, ternary compounds such as tantalum hafnium carbide, etc.

[0048] In some embodiments, the simulated ash and / or precursors include, but are not limited to, platinum group metals and noble metals, such as ruthenium (Ru), rhodium (Rh), palladium (Pd), osmium (Os), iridium (Ir), platinum (Pt), gold (Au), copper (Cu), silver (Ag), rhenium (Re), and mercury (Hg).

[0049] Advantageously, the simulated ash and / or its precursor preferably has a particle size of about 0.01 micrometers to about 1000 micrometers, more preferably about 0.1 micrometers to about 100 micrometers, and most preferably about 0.2 micrometers to about 50 micrometers.

[0050] On the other hand, a system for processing used particulate filters by the above method is disclosed. That is, each feature of the above aspects can be freely combined with this aspect, which also includes: a cleaning unit having a gas flow and / or liquid flow applicator configured to remove particles accumulated in the particulate filter; and a guiding unit configured to provide simulated ash and / or a precursor of simulated ash into the channels of the particulate filter after particle removal.

[0051] The system advantageously includes a detection unit for evaluating the particulate filter based on treatment criteria. For example, the treatment criteria may be selected as at least one of the following: a specific time period since the last treatment of the particulate filter, a specific mileage of the vehicle equipped with the particulate filter, the regeneration frequency of the particulate filter within the specific time period, the horsepower of the vehicle equipped with the particulate filter, warnings from indicator lights, and a specific back pressure of the particulate filter.

[0052] The system advantageously includes a control mechanism for deactivating the cleaning unit when the step of removing particles from the particulate filter is determined to be complete. For example, during filter purging, the cleaning unit is deactivated when no particles are visually observed being blown out of the filter. Alternatively, during filter purging, the cleaning unit is deactivated when no more particles are collected in the collection bag. Or, the cleaning unit is deactivated when the weight of the collection bag increases by less than a threshold (e.g., 0.1-1 g) within a specific time period. Or, the cleaning unit is deactivated when the back pressure of the entire filter assembly or a portion of the filter increases by less than a threshold, e.g., 0.1-1 mbar, within a specific time period. Alternatively, the cleaning unit is deactivated after completing a set of standard procedures (e.g., first loosening treatment followed by gas flow treatment).

[0053] The invention stems from a surprising discovery by the inventors while dealing with used particulate filters. As is common practice in the prior art, diesel particulate filters are treated after operation to remove particulate matter accumulated in the filter channels, thereby alleviating the unfavorable high back pressure in the engine system. However, since a decrease in particulate number (PN) filtration efficiency often occurs after particulate removal treatment, particulate filters may fail to meet increasingly stringent particulate number (PN) emission standards. After trying numerous methods to avoid this drawback, the inventors unexpectedly discovered that a DPF with particulate matter removed and further incorporating simulated ash into its inlet channel exhibits better PN removal efficiency than a DPF treated only with ash, a new DPF without any treatment, or a new DPF with simulated ash loading.

[0054] Based on the above findings, another aspect discloses a method for manufacturing a particulate filter, comprising: providing a particulate filter including a honeycomb structure; introducing simulated ash into the inlet channel of the honeycomb structure until the particulate filter meets the processing criteria; removing at least a portion of the simulated ash and / or particles from the inlet channel of the honeycomb structure; and introducing the simulated ash back into the inlet channel of the honeycomb structure.

[0055] In the above method, the processing criteria can be selected as at least one of the following: a specific regeneration frequency of the particulate filter within a specific time period, a specific horsepower of the vehicle with the particulate filter, a warning from an indicator light, or a specific back pressure of the particulate filter.

[0056] In the above method, before removing particles and re-introducing simulated ash, the particulate filter is treated by introducing simulated ash to represent some symptoms already experienced by the particulate filter. For example, the filter can be treated with a specific load of simulated ash, such as from about 0.1 g / L to 100 g / L, preferably from about 0.5 g / L to about 50 g / L, more preferably from about 1 g / L to about 10 g / L. Advantageously, the filter can be treated until a specific back pressure of the particulate filter is observed, such as from about 0.1 mbar to about 100 mbar, preferably from about 1 mbar to about 50 mbar, more preferably from about 5 mbar to 25 mbar, said back pressure being at 1020 m... 3 Measured at a flow rate of / hr (CMH). Alternatively, the filter may be processed until a specific particulate filtration efficiency or particulate number filtration efficiency is observed, for example, equal to or greater than 80%, preferably equal to or greater than 85%, more preferably equal to or greater than 90%, and even more preferably equal to or greater than 95%.

[0057] In another aspect, a system for producing a particulate filter using the method described above is disclosed. That is, each feature of this further aspect can be freely combined with that aspect, which also includes: a guiding unit configured to provide simulated ash and / or particles on the surface of an inlet channel of a honeycomb structure to be used in the particulate filter; and a cleaning unit having a gas and / or liquid flow applicator configured to remove the simulated ash and / or particles from the inlet channel of the honeycomb structure.

[0058] Unless otherwise expressly stated, each aspect defined in this disclosure may be combined with any other one or more aspects. In particular, any feature represented as preferred or advantageous may be combined with any other feature represented as preferred or advantageous, unless otherwise expressly stated. Attached Figure Description

[0059] The description will now be made with reference to the following non-limiting figures, in which:

[0060] Figure 1 This is a perspective view of an exemplary particulate filter;

[0061] Figure 2 yes Figure 1 A cross-sectional view of a particulate filter;

[0062] Figure 3 The steps for removing particles accumulated in the particle filter channels are shown; and

[0063] Figure 4 The steps of introducing simulated ash into the channel of a particle filter after the particle removal step are shown, or introducing simulated ash into the channel of a new particle filter.

[0064] Figure 5 A schematic diagram of an exemplary cleaning unit is shown, which has an airflow applicator for removing particles accumulated in the channels of a particulate filter;

[0065] Figure 6 A schematic diagram of a guiding unit is shown, which has a simulated ash applicator for providing simulated ash within the channels of a particle filter after the particle removal step;

[0066] Figure 7 A schematic diagram of an exemplary detection system for evaluating particulate filters is shown;

[0067] Figure 8 This is a graph showing the comparison results of the WHTC test cycle of the filter;

[0068] Figure 9 This is a graph showing the comparison results of the WHSC test cycle of the filter. Detailed Implementation

[0069] Before describing several exemplary embodiments of the present invention, it should be understood that the present invention is not limited to the details of the construction or process steps set forth in the following description. The present invention can have other embodiments and can be practiced or performed in various different ways.

[0070] The following definitions are provided for the terms used in this disclosure.

[0071] Throughout the specification, including the claims, the terms “comprising one” or “including one” shall be understood to be synonymous with the term “comprising at least one” unless otherwise stated, and “between” shall be understood to include the boundary.

[0072] The terms “a,” “an,” and “the” are used to refer to a grammatical object of one or more (i.e., at least one) items.

[0073] The term “and / or” includes the meaning of “and”, “or”, and all other possible combinations of elements associated with the term.

[0074] Unless otherwise stated, all percentages and ratios are by weight.

[0075] As used herein, the terms “catalyst” or “catalytic material” or “catalytic material” refer to a material or mixture of materials that promotes a reaction.

[0076] As is known in the art, particulate filters can be used to remove particles, particles, or particulate matter from exhaust gas, which can be generated from any source, including, for example, internal combustion engines such as lean-burn engines, diesel engines, natural gas engines, gasoline engines, power plants, incinerators, etc.

[0077] Figure 1 The filter media in the form of a conventional wall-flow honeycomb filter is shown. In actual production or operation, the filter typically also includes a housing for protecting and retaining the filter media. The filter shown in the figure has a first end and a second end, defining a longitudinal direction between them. In use, one of the two ends, such as the first end 11, will be configured as the inlet end of the exhaust gas 13, while the other second end 12 will be configured as the outlet end of the treated gas 14.

[0078] Further reference Figure 2The filter has multiple channels defined by a wall 17 extending in the longitudinal direction. A first set of channels, referred to herein as inlet channel 15, opens at a first end 11 and closes at a second end 12 with, for example, a sealing material. A second set of channels, referred to herein as outlet channel 16, opens at the second end 12 and is also closed at the first end 11 with a sealing material. This structure forms a checkerboard pattern at either end of the bulk material and allows exhaust gas 13 and entrained particles to enter the inlet channel 15, flow through the porous wall 17, and flow into the outlet channel 16 as treated gas 14. Exhaust gas 13 entering the inlet channel 15 from the first end 11 cannot leave the bulk material 10 without diffusing through the channel wall 17. Therefore, particles are filtered out from the exhaust gas and accumulate on the inner surface of the inlet channel 15.

[0079] Preferably, in a plane orthogonal to the longitudinal direction, the filter has 100 to 500 channels per square inch, more preferably 200 to 400 channels. The channels may have rectangular, square, circular, elliptical, triangular, hexagonal, or other polygonal cross-sections; or the channels may have other geometries suitable for the application.

[0080] In one or more embodiments, the number of inlet channels 15 is equal to the number of outlet channels 16, and each channel is configured to have the same shape and size, and all channels are evenly distributed throughout the entire material.

[0081] In alternative embodiments, the number of inlet channels 15 differs from the number of outlet channels 16, and each channel may be configured to have different and / or the same form and size, and at least some channels are non-uniformly distributed throughout the bulk material.

[0082] The filter can be formed from any material known in the art. For example, as described below, the filter is a wall-flow ceramic filter because it can remove a large amount of particulate matter from diesel engine exhaust. The filter is advantageously constructed from refractory materials such as cordierite, silicon carbide, or aluminum titanate.

[0083] In one or more embodiments, the channels of the filter may be coated with a functional material layer or a catalyst composition. The functional material layer may be coated on the inner surface of the inlet channel 15, the inner surface of the outlet channel 16, or both the inner surfaces of the inlet channel 15 and the outlet channel 16 of the porous wall of the filter.

[0084] To avoid any doubt, the invention is described in this specification using the term "wall-flow ceramic filter." Although wall-flow ceramic filters are preferred, this description is not limiting, and the invention is not limited to such wall-flow ceramic filters.

[0085] The catalyst composition deposited along the inner surface of the channel aids in filter regeneration by promoting the combustion of accumulated particulate matter. The combustion of the accumulated particulate matter restores acceptable back pressure within the exhaust system. These processes can be passive or active regeneration processes. Both processes utilize oxidants such as O2 or NO2 to burn the particulate matter.

[0086] In one or more embodiments, the filter is coated with a catalyst to promote NO. x Conversion. In one or more embodiments, the filter is coated with a catalyst to perform CO oxidation, hydrocarbon storage, hydrocarbon oxidation, and NO conversion. x It has at least one of the following functions: storage, NO oxidation, and fuel ignition.

[0087] In one or more embodiments, the catalyst composition is located inside and / or on the wall of the filter.

[0088] In one or more embodiments, at least about 5% by volume of the catalyst composition is located within the wall of the filter, preferably at least about 10% by volume of the catalyst composition is located within the wall of the filter, and more preferably at least about 20% by volume of the catalyst composition is located within the wall of the filter.

[0089] In one or more embodiments, a filter is coated on the inner surface of the bulk feed inlet channel. In several other embodiments, a filter is coated in the bulk feed outlet channel. In still several embodiments, a filter is coated with at least one catalyst composition from both the bulk feed inlet channel and outlet channel.

[0090] In one or more embodiments, the catalyst composition comprises, for example, platinum, palladium, ruthenium, rhodium, osmium, iridium, and / or gold (Pt, Pd, Ru, Rh, Os, Ir, and / or Au). Other catalytic components that effectively promote soot combustion include vanadium, tungsten, silver, rhenium, cerium dioxide, iron, manganese, nickel, copper (V, W, Ag, Re, Ce, Fe, Mn, Ni, Cu), and combinations thereof. These catalytic components may be used alone or on a support material.

[0091] In one or more embodiments, the filter includes a porous wall having an average pore size and a catalyst coating having an average particle size, wherein the ratio of the filter's average pore size to the catalyst's average particle size distribution is in the range of 0.5 to 50, and / or the ratio of the filter's average pore size to the catalyst's average particle size distribution is in the range of 0.25 to 30.

[0092] Besides using oxidation catalysts, diesel particulate filters are also used to achieve significant particulate reduction in diesel engine emission treatment systems. Known filter structures for removing particulate matter from diesel engine exhaust include wall-flow honeycomb filters, fiber-wound or fiber-filled filters, open-cell foam, sintered metal filters, etc. However, the wall-flow ceramic filters described below are of the greatest interest. These filters can remove more than 90% of particulate matter from diesel engine exhaust.

[0093] Typical wall-flow ceramic filter substrates are made of refractory materials such as cordierite or silicon carbide. Wall-flow substrates are particularly useful for filtering particulate matter from diesel engine exhaust. A common structure is a multi-channel honeycomb structure, with the ends of alternating channels on the inlet and outlet sides of the honeycomb structure blocked. This structure forms a checkerboard pattern at both ends. The channel blocked at the axial end of the inlet is open at the axial end of the outlet. This allows exhaust gas carrying entrained particles to enter the open inlet channel, flow through the porous inner wall, and exit through the channel at the open axial end of the outlet. The particles are thus filtered onto the inner wall of the substrate. Gas pressure forces the exhaust gas through the porous structure wall into the channel that is closed at the upstream axial end and open at the downstream axial end. A filter is a physical structure used to remove particles from exhaust gas. Accumulated particles increase the back pressure of the filter on the engine. Therefore, accumulated particles must be burned off from the filter continuously or periodically to maintain acceptable back pressure. Unfortunately, soot particles require temperatures exceeding 500°C to burn under oxygen-rich (oxygen-deficient) exhaust conditions. This temperature is higher than the temperature typically found in diesel engine exhaust.

[0094] Catalyst compositions deposited along the inner wall of a wall-flow filter matrix contribute to the regeneration of the filter matrix by promoting the combustion of accumulated particulate matter. The combustion of accumulated particulate matter restores acceptable back pressure within the exhaust system. These processes can be passive or active regeneration processes. Both processes utilize oxidants such as O2 or NO2 to burn the particulate matter.

[0095] The passive regeneration process burns particulate matter at temperatures within the normal operating range of the diesel engine exhaust system. Preferably, the oxidant used in the regeneration process is NO2, because the soot portion burns at a much lower temperature than required when O2 is used as an oxidant. While O2 is readily available from the atmosphere, NO2 can be actively generated using an upstream oxidation catalyst for NO in the oxidizing exhaust stream.

[0096] Despite regulations governing catalyst compositions and the use of NO2 as an oxidant, an active regeneration process is typically required to remove accumulated particulate matter and restore acceptable back pressure within the filter. The soot portion of particulate matter generally requires temperatures exceeding 500°C to burn under oxygen-rich (or oxygen-deficient) conditions, higher than temperatures typically found in diesel engine exhaust. Active regeneration is usually initiated by altering engine management to raise the temperature before the filter to approximately 550°C to approximately 850°C. Depending on the driving mode, significant exothermic reactions can occur inside the filter when cooling is insufficient during regeneration (low speed / low load or idling driving modes). This exothermic reaction can exceed 850°C or higher within the filter.

[0097] In one or more embodiments, the soot filter is coated with a catalyst to promote soot combustion, thereby promoting filter regeneration. In one or more embodiments, the soot filter is coated with a catalyst to promote NO... x Conversion. In one or more embodiments, the soot filter is coated with a catalyst to perform CO oxidation, hydrocarbon storage, hydrocarbon oxidation, and NO conversion. x It has at least one of the following functions: storage, NO oxidation, and fuel ignition.

[0098] In one or more embodiments, a catalytic soot filter (CSF) is positioned downstream of the diesel oxidation catalyst.

[0099] In one or more embodiments, the catalytic soot filter has a plurality of longitudinally extending channels defined by longitudinally extending walls. In several specific embodiments, the inlet channel has an open inlet end and a closed outlet end, and the outlet channel has a closed inlet end and an open outlet end. In one or more embodiments, the soot filter comprises a wall-flow straightener with a wall porosity of about 40% to about 70%. In one or more embodiments, the soot filter comprises a wall-flow straightener with an average pore size of about 5 micrometers to about 30 micrometers.

[0100] In one or more embodiments, the catalytic soot filter contains a catalyst composition at least in or on the walls of the soot filter. In one or more embodiments, the catalyst composition may be coated, for example, as a catalyst coating in or on the walls of the soot filter.

[0101] In one or more embodiments, the soot filter is coated with at least one catalyst that permeates into the wall of the wall-flow straightener. In several other embodiments, the soot filter is coated with at least one catalyst on the wall of the wall-flow straightener. In still other embodiments, at least one catalyst is coated on the wall of the soot filter and permeates into the wall of the wall-flow straightener.

[0102] In one or more embodiments, a soot filter is coated from the inlet channel of the wall-flow straightener. In several other embodiments, a soot filter is coated from the outlet channel of the wall-flow straightener. In several other embodiments, both the inlet and outlet channels of the wall-flow straightener are coated with at least one catalyst composition.

[0103] In one or more embodiments, the catalytic soot filter includes one or more catalytic materials. The catalytic material may be present only in or on the inlet side of the wall, only in or on the outlet side, in or on both the inlet and outlet sides, or the wall itself may be wholly or partially composed of the catalytic material.

[0104] In one or more embodiments, the catalytic soot filter includes or uses one or more layers of catalytic material and a combination of one or more layers of catalytic material in the inlet wall and / or outlet wall.

[0105] In one or more embodiments, the catalytic soot filter effectively burns particulate matter and nitrogen dioxide, and effectively optimizes the ratio of NO to NO2 leaving the filter.

[0106] In one or more embodiments, the CSF composition comprises at least one PGM, such as platinum, palladium, ruthenium, rhodium, osmium, iridium, and / or gold (Pt, Pd, Ru, Rh, Os, Ir, and / or Au). Other catalytic components that effectively promote soot combustion include vanadium, tungsten, silver, rhenium, cerium dioxide, iron, manganese, nickel, copper (V, W, Ag, Re, Ce, Fe, Mn, Ni, Cu), and combinations thereof. These catalytic components may be used alone or on a support material. In several specific embodiments, the CSF composition disclosed herein comprises about 0.5 g / ft. 3 Approximately 250g / ft 3 The total PGM load is calculated as the ratio of the total weight of the PGM elements to the volume of the CSF catalyst; or the CSF composition disclosed herein contains a total PGM load of from about 0.01 wt% to about 10 wt% based on the weight of the dry CSF composition.

[0107] In several specific embodiments, the CSF compositions disclosed herein contain a platinum (Pt) component but not palladium (Pd). In several other specific embodiments, the CSF compositions disclosed herein contain a palladium (Pd) component but not platinum (Pt). In several other specific embodiments, the CSF compositions disclosed herein contain both a platinum component and a palladium component.

[0108] In one or more embodiments, the CSF composition may comprise, for example, from about 0.002 wt% to about 8 wt% of platinum component based on the weight of the dry CSF composition. The CSF composition may comprise, for example, about 0.1 g / ft of CSF catalyst.3 Approximately 167 g / ft 3 The CSF composition may contain a platinum component. The CSF composition may contain, for example, from about 0.002 wt% to about 8 wt% of palladium component based on the weight of the dry CSF composition. The CSF composition may contain, for example, about 0.1 g / ft of CSF catalyst. 3 Approximately 167 g / ft 3 The palladium component.

[0109] In one or more embodiments, the Pt / Pd weight ratio is from about 20:1 to about 1:20. In some embodiments, the Pt / Pd weight ratio is from about 10:1 to about 1:5. In some embodiments, the Pt / Pd weight ratio is from about 3:1 to about 1:3.

[0110] In one or more embodiments, the platinum and palladium components of the disclosed CSF composition are both supported on a carrier material (wherein the carrier materials supporting the platinum and palladium components may be the same or different).

[0111] In one or more specific embodiments, the metal oxide support that can be used in the CSF compositions disclosed herein is a doped alumina material, such as silicon-doped alumina (including but not limited to 1-10% SiO2-Al2O3), a doped titanium dioxide material such as silicon-doped titanium dioxide (including but not limited to 1-15% SiO2-TiO2), or a doped zirconium oxide material such as silicon-doped ZrO2 (including but not limited to 5-30% SiO2-ZrO2), or a high surface area metal oxide support such as alumina or titanium dioxide support material, typically exhibiting about 50 μm 2 / g to approximately 400m 2 / g, preferably about 60m 2 / g to approximately 350m 2 / g, more preferably about 90m 2 / g to approximately 250m 2 The total surface area (BET) is approximately 0.3 cm² / g. In one or more specific embodiments, the carrier material has a surface area of ​​approximately 0.3 cm² / g. 3 / g to approximately 1.5cm 3 The total pore volume (BET) is in the range of / g. In one or more specific embodiments, the activated alumina has an average pore size (BET) in the range of about 2 nm to about 50 nm.

[0112] In one or more embodiments, the CSF catalyst composition may comprise a hydrocarbon storage or hydrocarbon adsorption component. For example, the bottom or top layer of the CSF catalyst may further comprise a hydrocarbon storage or hydrocarbon adsorption component selected from molecular sieves or zeolites, or cerium dioxide-containing molecular sieves, or cerium dioxide-containing metal oxides. The hydrocarbon storage or hydrocarbon adsorption component may be added in H+ form. The hydrocarbon storage or hydrocarbon adsorption component may also comprise one or more catalytically active metals selected from PGMs (e.g., platinum, palladium, rhodium, etc.), copper, iron, cerium, zirconium, barium, manganese, magnesium, cobalt, nickel, rare earth metal oxides, base metal oxides, etc.

[0113] In one or more embodiments, a catalytic soot filter containing a catalyst that promotes the SCR reaction is effective in two functions: removing particulate components from the exhaust stream and removing NO from the exhaust stream. x The component is converted into N2. In several specific implementation schemes, NO can be achieved. x The reduced catalytic soot filter is deposited with an SCR catalyst composition.

[0114] Another aspect to consider in catalytic soot filters is selecting a suitable SCR catalyst composition. First, the catalyst composition must be heat-resistant so that it maintains its SCR catalytic activity even after prolonged exposure to the high temperatures characteristic of filter regeneration. Second, the SCR catalyst composition preferably has a sufficiently wide operating temperature range so that it can adapt to the variable temperature range of vehicle operation. For example, it typically withstands temperatures below 300°C under low load conditions or during startup. Catalytic soot filters should also exhibit high specific activity and high hydrothermal stability.

[0115] In one or more embodiments, a catalytic soot filter including a catalyst that promotes the SCR reaction is effective in two functions: removing particulate components from the exhaust stream and removing NO from the exhaust stream. x The component is converted into N2. In several specific implementation schemes, NO can be achieved. x The reduced catalytic soot filter is deposited with an SCR catalyst composition.

[0116] In one or more embodiments, under engine operating conditions, NO via CSF x The conversion rate in the system NO x The conversion rate is in the range of about 10% to about 100%, preferably in the range of about 20% to about 100%, and more preferably in the range of about 25% to about 100%.

[0117] In one or more embodiments, the CSF comprises at least one zeolite component and a base metal component selected from one or both of copper and iron.

[0118] In some preferred embodiments, the SCR catalyst composition comprises 95% to 100% by weight, preferably 98% to 100% by weight, more preferably 99% to 100% by weight, of a zeolite material framework composed of Si, Al, O, and optionally H, wherein the molar ratio of Si to Al, calculated as molar SiO2:Al2O3, in the framework is preferably in the range of 2:1 to 50:1, more preferably in the range of 2:1 to 45:1, more preferably in the range of 10:1 to 19:1, and even more preferably in the range of 14:1 to 18:1.

[0119] In several specific embodiments, the CSF comprises Cu and a zeolite having a framework type preferably selected from, but not limited to, CHA, AEI, BEA, MFI, FAU, MOR, AFX, and LTA. In one specific embodiment, the CSF comprises Cu and a zeolite having a CHA structure. In another specific embodiment, the CSF comprises Cu and a zeolite having an AEI structure.

[0120] In several other embodiments, the CSF comprises Fe and a framework type preferably selected from, but not limited to, zeolites of CHA, AEI, BEA, MFI, FAU, MOR, AFX, and LTA. In one embodiment, the CSF comprises Fe and a zeolite having a BEA structure. In another embodiment, the CSF comprises Fe and a zeolite having a CHA structure.

[0121] Zeolite compositions that can be used according to one or more specific embodiments of CSF include zeolites having a CHA or AEI structure. Exemplary CHA or AEI zeolites have a silica / alumina molar ratio (SAR) greater than about 8. In a preferred embodiment, the silica to alumina molar ratio (SAR) of CHA is about 10 to about 35. In another preferred embodiment, the silica to alumina molar ratio (SAR) of AEI is about 14 to 19.

[0122] In one or more embodiments, the base metal component selected from copper and iron, calculated as a metal oxide, comprises more than about 0.2% by weight of the total weight of the oxide plus the zeolite-based catalyst composition. In several preferred embodiments, the base metal component comprises about 0.2% by weight to about 8% by weight, preferably about 2% by weight to about 6% by weight.

[0123] Other useful compositions for CSF include non-zeolite molecular sieves. For example, according to one or more embodiments, silica-aluminophosphates, such as, but not limited to, SAPO-34, SAPO-44, and SAPO-18, can be used.

[0124] In one or more embodiments, the CSF comprises at least one inorganic metal oxide material selected from vanadium oxide and molybdenum oxide. In several other embodiments, the CSF comprises a mixed oxide of vanadium oxide and titanium oxide. In some other embodiments, the CSF comprises a mixed oxide of vanadium oxide, silicon oxide, and titanium oxide. In some other embodiments, the CSF comprises a mixed oxide of vanadium oxide, tungsten oxide, and titanium oxide. In some other embodiments, the CSF comprises a mixed oxide of vanadium oxide, antimony oxide, and titanium oxide.

[0125] In one or more embodiments, the CSF catalyst composition has a particle size distribution of about 1 micrometer to about 10 micrometers. 50 In one or more embodiments, the CSF catalyst composition has a particle size distribution of about 2 micrometers to about 30 micrometers. 90 .

[0126] In one or more embodiments, the total surface area (BET) of the CSF catalyst composition is approximately 50 m². 2 / g to approximately 700m 2 In the range of / g. In one or more embodiments, the total pore volume (BET) of the CSF catalyst composition is in the range of about 0.3 cm. 3 / g to approximately 1.5cm 3 The average pore size (BET) of the CSF catalyst composition is in the range of about 2 nm to about 50 nm in one or more embodiments.

[0127] In one or more embodiments, the CSF includes a porous filter wall having an average pore size; and a catalyst coating having an average particle size; wherein the average pore size of the filter is related to the average particle size distribution of the catalyst D. 50 The ratio is in the range of 0.5 micrometers to 50 micrometers, and / or the average pore size of the filter is related to the average particle size distribution of the catalyst. 90 The ratio ranges from 0.25 micrometers to 30 micrometers.

[0128] “D 90 "and "D 50 "With their usual meaning, they refer to the points where the cumulative volume on the smaller particle size side reaches 90% and 50% in the cumulative particle size distribution. D" 90 These values ​​were determined by measuring the particle size distribution. The particle size distribution was measured using a laser diffraction particle size distribution analyzer.

[0129] In one or more embodiments, the CSF is coated with at least one catalyst, and the coating loading (dry gain) is about 0.05 g / in. 3 Approximately 3.0 g / in 3 The preferred concentration is approximately 0.1 g / in. 3Approximately 2.5 g / in 3 .

[0130] Now refer to Figure 3-6 A method and system for treating used particulate filters according to one embodiment of the present invention are described.

[0131] According to one implementation, this method is useful for treating used filters to meet specific treatment criteria, where used filters are those that have been overused in performing their filtration functions. The treatment criteria can be selected as at least one of the following: a specific time period since the particulate filter was last treated, a specific mileage of the vehicle with the particulate filter, the regeneration frequency of the particulate filter within the specific time period, the horsepower of the vehicle with the particulate filter, a warning from an indicator light, or a specific back pressure of the particulate filter.

[0132] If the filter is assessed as not meeting any criteria, no treatment is required. On the other hand, if the filter is assessed as meeting at least one treatment criterion, the next step of removing particles accumulated in the particulate filter will be performed.

[0133] Different filter cleaning methods have been developed, such as pressurized air-based cleaning procedures and wash-based procedures. Cleaning procedures can be combined with heat treatment.

[0134] Air-based cleaning procedures typically involve pressurized air and optional air with CO2, a cleaning time of approximately 20 to 30 minutes, a pressure of approximately 3 to 8 bar, and 0%–8% CO2.

[0135] Counter-current pneumatic cleaning is currently the most common method for cleaning and removing ash from diesel particulate filters. While there are various variations of the process, the basic cleaning method involves driving a flow of gas through the filter from the outlet side (counter-current) and collecting the ash blown out of the filter in a suitable dust collection system. Various commercial cleaning systems exist, utilizing either localized applications of high-pressure air, such as air knives, or low-pressure but high-flow-rate flows across the entire cross-section of the filter. Prior to pneumatic cleaning, the filter can also be heated in an oven to oxidize any residual soot.

[0136] In addition, some less common cleaning methods include wet cleaning, in which water or some other cleaning agent is used to rinse through a filter to remove ash. Wet cleaning is typically performed in a factory remanufacturing center and requires a properly designed filter substrate, pad, and housing that are compatible with the cleaning solution.

[0137] Other advanced cleaning technologies have also been proposed, but they are either not yet on the market or not mainstream.

[0138] Figure 3A schematic diagram of exemplary steps for removing particles accumulated in a particulate filter channel is shown. As shown, the filter 10 is positioned such that a gas flow 52 is blown into an outlet channel 16 at the outlet end, and particles 20 accumulated in the inlet channel 15 are blown out from the outlet end.

[0139] In one example, the gas flow has a pressure of about 1-15 bar and / or a flow rate of about 100-10000 liters per minute.

[0140] Advantageously, this step further includes applying a gas flow at the inlet end of the particulate filter to loosen particles on the inner surface of the particulate filter before the gas flow is blown into the outlet channel. Other measures known in the art for loosening particles accumulated in the channel may be used alternatively or in combination. After loosening the particles, a gas flow is applied at the outlet end of the particulate filter to remove the particles from the particulate filter. It is understood that the step of loosening the particles can be omitted.

[0141] Advantageously, the particulate removal step also includes exposing the particulate filter to temperatures as high as approximately 450°C to 850°C. The purpose of this step is to burn the soot portion of the particulate matter under oxygen-enriched conditions, at temperatures higher than those typically found in diesel engine exhaust. This process, known in the art as an active regeneration process, is typically initiated by altering engine management to raise the temperature before the filter to approximately 550°C to approximately 650°C. Depending on the drive mode, high exothermic temperatures can occur within the filter when the engine is not adequately cooled (e.g., in low-speed, low-load, or idling drive modes). This exothermic effect can exceed 800°C or higher within the filter.

[0142] The process of removing particles accumulated in the particulate filter channels can be performed using, for example, a PURItech ash cleaner or a PURIcleaning M / C E1. One implementation of the cleaning unit is based on the principle of... Figure 5 As shown in the diagram. The cleaning unit includes an airflow applicator 51 that provides a gas flow 52. Optionally, an injector 53 is configured to extend from the applicator 51 to inject the gas flow 52. The injector 53 has a configuration that covers the end of the filter, or is configured to move along the entire area of ​​the filter end to apply a gas flow to each channel. A retainer 54 is provided to hold the particulate filter in the cleaning unit during cleaning. Optionally, an ash outlet 55 and an ash collector 56 may be provided to collect particles discharged from the particulate filter.

[0143] During the cleaning step, the filter is inserted inverted (outlet end upward) into the cleaning unit on the retainer. A gas flow is applied from the injector into and through the filter. In one embodiment, the injector moves from channel to channel until the entire end area is covered. The filter is then reversed so that the inlet end is upward, and a gas flow is introduced into the filter's inlet channel. The cleaning step may be repeated several times, for example, four times in total, including twice with the filter inlet end upward and twice with the outlet end upward. The gas flow may be set to, for example, a pressure of 8 bar and / or a flow rate of 1000 liters per minute.

[0144] Advantageously, the cleaning unit includes a control mechanism that can, for example, determine the cleanliness of the filter and stop the gas flow. For example, during filter purging, the cleaning unit is deactivated when no particles are visually observed being blown out of the filter. Alternatively, during filter purging, the cleaning unit is deactivated when no more particles are collected in the collection bag. Alternatively, the cleaning unit is deactivated when the weight of the collection bag increases by less than a threshold (e.g., 0.1-1 g) within a specific time period. Alternatively, the cleaning unit is deactivated when the back pressure of the entire filter assembly or a portion of the filter increases by less than a threshold (e.g., 0% to 5% of the initial back pressure) within a specific time period. Alternatively, the cleaning unit is deactivated after completing a set of standard procedures, such as first performing particle loosening treatment and then gas flow treatment.

[0145] After the step of removing particles accumulated in the particulate filter is completed, the filter will be further processed by providing simulated ash and / or precursors of simulated ash into the channels of the particulate filter. Figure 4 A schematic diagram illustrating the steps of introducing simulated ash into the channel of a particulate filter is shown. As shown, simulated ash 30 and / or precursors of simulated ash are blown into the inlet channel 15 of the particulate filter 10 by applying a gas flow 31.

[0146] In one embodiment, the step of introducing simulated ash includes further processing the particulate filter after introducing the simulated ash into the channels of the particulate filter. In one embodiment, such processing includes exposing the particulate filter to thermal conditions, such as not less than 300°C, more preferably not less than 350°C, and most preferably not less than 400°C.

[0147] In one embodiment, the step of introducing simulated ash includes introducing a precursor into a channel of a particulate filter and further processing the particulate filter to convert the precursor into simulated ash. In one embodiment, such processing includes exposing the particulate filter to thermal conditions, such as not less than 300°C, more preferably not less than 350°C, and most preferably not less than 400°C.

[0148] In one embodiment, the droplet and / or solid particle flow is at a speed of 100-10000 m. 3 / h provides.

[0149] In one implementation, the simulated ash content is provided at a rate of not less than about 0.05 grams per liter of particulate filter volume.

[0150] In one embodiment, droplets and / or solid particle streams are introduced into the particle filter by blowing, suction, spraying, and / or coating.

[0151] In this method, the simulated ash and / or precursor preferably comprises one or more of the following: alumina, zinc oxide, zinc carbonate, calcium oxide, calcium carbonate, cerium zirconium oxide, zirconium oxide, cerium oxide, and hydrated alumina; more preferably, it comprises one or more of the following: zinc oxide, zinc carbonate, calcium oxide, calcium carbonate, and zirconium oxide. Advantageously, the simulated ash has a porous structure that can exist at a temperature not lower than 300°C. Advantageously, the simulated ash and / or its precursor preferably has a particle size of about 0.01 micrometers to about 1000 micrometers, more preferably about 0.1 micrometers to about 100 micrometers, and most preferably about 0.2 micrometers to about 50 micrometers.

[0152] The steps for providing simulated ash and / or precursors within the channels of a particulate filter can be performed by a guiding unit, such as... Figure 5 As shown. Figure 6 The principle of the guiding unit is illustrated. As shown, the cleaning unit includes an airflow applicator 61 that provides a gas flow. The cleaning unit also includes a simulated ash source 62 for providing simulated ash and / or precursor 30. The conduits of the airflow applicator 61 and the simulated ash source 62 are connected to form a flow 63 of simulated ash / precursor flowing out of the ejector 64 at a sufficient flow rate. A retainer 65 is disposed in the guiding unit to hold the filter 10. The filter is held on the retainer 65 with its inlet end opposite the ejector 64, allowing simulated ash to be blown into the inlet channel. Furthermore, an outlet 66 and a dust collector 67 are disposed below the retainer 65 to collect any particulate matter and simulated ash escaping from the filter outlet end.

[0153] Advantageously, the guiding unit also includes a control mechanism that can, for example, determine the completion of introducing simulated ash into the inlet channel of the particulate filter.

[0154] Some advantages of the methods and systems according to some embodiments of the present invention are achieved through, for example... Figure 7-9 The comparative experiment shown illustrates this.

[0155] To conduct a comparative experiment, a special design was created, such as... Figure 7The detection system shown includes an engine 71, a diesel oxidation catalyst (DOC) 72, and a particulate matter counter 73. A filter 10 is located between the DOC and the detection counter. Additionally, a fuel spray injector 74 is installed before / upstream of the DOC 72 to inject fuel 76 into the exhaust stream 75 from the engine 71. In this system, the DOC is a commercially available 12”×12”×6” diesel oxidation catalyst with a PGM loading of 50 g / ft at a 2” front section length. 3 1:2, with a PGM load of 20 g / ft at a rear region length of 4”. 3 The ratio is 10:1, and the particle counter is AVL 489.

[0156] This testing system simulates a real-world working environment to test filters in the WHTC and WHSC cycles, which are globally accepted for evaluating diesel engine performance in several aspects, particularly PN removal efficiency. Details of the WHTC and WHSC cycles are defined, for example, in the Chinese national regulation GB17691-2018 (Limits and Measurement Methods for Emissions from Diesel Fueled Heavy-Duty Vehicles (China VI)). To ensure minimal impact of soot on the evaluation results, the testing system includes a fuel spray injector 74 upstream of DOC72 to inject fuel 76 into the exhaust stream 75 to clean soot from the filter under test.

[0157] The present invention is further illustrated by the following embodiments, which do not limit the scope of the invention, but are only used to illustrate some embodiments of the invention.

[0158] Implementation Scheme 1. A method for treating a used particulate filter, the method comprising: removing particles from the particulate filter; and introducing simulated ash into an inlet channel of the particulate filter after particle removal.

[0159] Implementation Scheme 2. The method according to Implementation Scheme 1, wherein the particulate filter is used to remove exhaust particles generated by the internal combustion engine.

[0160] Implementation Scheme 3. The method according to any one of the foregoing implementation schemes, wherein the particulate filter has at least one of the following: a specific time period since the last treatment of the particulate filter, a specific mileage of the vehicle with the particulate filter, a specific regeneration frequency of the particulate filter within the specific time period, a specific horsepower of the vehicle with the particulate filter, a warning from an indicator light, a signal from a sensor, a specific back pressure of the particulate filter, and a specific load of particulate matter.

[0161] Implementation Scheme 4. The method according to any one of the foregoing embodiments, wherein the step of removing particles includes applying a gas flow and / or a liquid flow at the outlet end and / or inlet end of the particle filter.

[0162] Implementation Scheme 5. The method according to Implementation Scheme 4, wherein the step of removing particles includes exposing the particulate filter to a temperature of up to about 450°C to 850°C.

[0163] Implementation Scheme 6. The method according to Implementation Scheme 4 or 5, wherein the gas flow is provided at a pressure of about 1-15 bar and / or a flow rate of about 100-10000 liters / minute.

[0164] Implementation Scheme 7. The method according to any one of the foregoing embodiments, wherein the step of introducing simulated ash comprises introducing droplets and / or solid particles of simulated ash and / or precursors of simulated ash into the channel of the particle filter through the inlet end of the particle filter.

[0165] Implementation Scheme 8. The method according to any one of the foregoing implementation schemes, wherein the step of introducing simulated ash comprises: introducing simulated ash into the channel of the particulate filter; and optionally subjecting the particulate filter to further heat treatment.

[0166] Implementation Scheme 9. The method according to any one of the foregoing embodiments, wherein the step of introducing simulated ash comprises introducing a precursor into a channel of the particulate filter and further processing the particulate filter to convert the precursor into simulated ash.

[0167] Implementation Scheme 10. The method according to Implementation Scheme 7, wherein 100-10000m 3 A flow rate of / h provides the droplet and / or solid particle flow.

[0168] Implementation Scheme 11. The method according to any one of Implementation Schemes 7-10, wherein the particulate filter is provided with not less than about 0.05 grams of simulated ash per liter.

[0169] Implementation Scheme 12. The method according to any one of Implementation Schemes 7-11, wherein the droplet and / or solid particle stream is introduced into the particulate filter by blowing, suction, spraying and / or coating.

[0170] Implementation Scheme 13. The method according to any one of Implementation Schemes 7-12, wherein the simulated ash has a porous structure capable of existing at a temperature not lower than 300°C.

[0171] Implementation Scheme 14. The method according to any one of Implementation Schemes 7-13, wherein the simulated ash and / or its precursor has a particle size of about 0.01 micrometers to about 1000 micrometers.

[0172] Implementation Scheme 15. A system for treating a used particulate filter by any one of embodiments 1-14, the system comprising: a cleaning unit having an applicator for a gas flow and / or a liquid flow configured to remove particles accumulated in the particulate filter; and a guiding unit configured to provide simulated ash and / or a precursor of simulated ash into a channel of the particulate filter after particle removal.

[0173] Implementation Scheme 16. The system according to Implementation Scheme 15 further includes a detection unit for evaluating the particulate filter using processing standards.

[0174] Implementation Scheme 17. The system according to at least one of the foregoing embodiments further includes a control unit configured to deactivate the cleaning unit and / or the guiding unit when determining that the step of removing particles from the particulate filter and / or the step of introducing simulated ash into the inlet channel of the particulate filter is completed.

[0175] Implementation Scheme 18. A method of manufacturing a particulate filter, comprising: providing a particulate filter having a honeycomb structure; introducing simulated ash into an inlet channel of the honeycomb structure; removing at least a portion of the simulated ash and / or particles from the inlet channel of the honeycomb structure; and introducing the simulated ash back into the inlet channel of the honeycomb structure.

[0176] Implementation Scheme 19. A system for manufacturing a particulate filter using the method according to Implementation Scheme 18, the system comprising: a guiding unit configured to provide simulated ash and / or particles on the inner surface of an inlet channel of a honeycomb structure to be used in the particulate filter; and a cleaning unit having an applicator having a gas flow and / or a liquid flow configured to remove the simulated ash and / or particles from the inlet channel of the honeycomb structure.

[0177] Example 1:

[0178] Choose a commercial diesel particulate filter (DPF) with a coating containing 3g / ft. 3 (Pt:Pd = 1:0)PGM, this coating is applied to an Ibiden SD084 SiC substrate. The DPF dimensions are 10.5 inches × 10.5 inches × 7.5 inches. The DPF was used in a vehicle that had traveled 230,000 kilometers, accumulating a significant amount of particulate matter in its channels. Then, with... Figure 7 The detection system removes soot from the DPF, and then uses... Figure 5 The cleaning unit shown removes ash, and then uses... Figure 7The above-mentioned soot removal process involves injecting fuel through fuel injector 74 before DOC 72. DOC 72 oxidizes the fuel, generating exothermic heat. The DPF at position 10 is maintained at ≥600°C for ≥1 hour at both the DPF inlet and outlet, with a space velocity (SV) ≥60,000 / h. The above-mentioned ash removal process is performed using a PURItech soot cleaner, PURIcleaning M / C E1. The above-mentioned soot removal process follows these steps: 1) sample inspection, 2) heat treatment in an oven (key parameters: ≥500°C, up to 8 hours, oxygen atmosphere), 3) gas flow cleaning (key parameters: outlet end upward, apply gas flow, then flip the filter, inner end upward, apply gas flow, repeat at least four times, blow compressed air, pressure 8 Bar, flow rate ≥1000 L / min). The completion of the above-mentioned ash removal process is determined by no change in back pressure and no change in filter weight. The WHSC test results are recorded as follows: Figure 8 In Example 1, the WHTC test results were recorded as follows: Figure 9 Example 1.

[0179] Example 2:

[0180] Use as Figure 6 The guide unit shown further loads the DPF with simulated ash, and then uses... Figure 7 The testing system was used for testing. The WHSC test results were recorded as follows: Figure 8 In Example 2, the WHTC test results were recorded as follows: Figure 9 Example 2. In this step, the DPF is loaded with 1.25 g / L of simulated ash. The airflow rate is set to 1000 m³ / h and lasts for at least 15 seconds.

[0181] Example 3:

[0182] Choose a new commercially available DPF that has not been used in any engine. This means the new filter will not accumulate particulate matter in the channels. The new DPF uses... Figure 6 The guide unit shown loads simulated ash, and then uses... Figure 7 The detection system was tested. The WHSC test results were recorded as follows: Figure 8 In Example 3, the WHTC test results were recorded as follows: Figure 9 Example 3.

[0183] like Figure 8 As shown, Example 2 (in which the filter is treated with the method according to the invention) has the lowest PN emissions and the best PN removal efficiency among the three examples of the WHSC cycle.

[0184] at the same time, Figure 9Example 2 is shown in which the filter is treated with the method according to the invention. Example 2 has the lowest PN emissions and the best PN removal efficiency among the three examples in the WHTC cycle.

[0185] In summary, used DPFs that have undergone particle removal treatment followed by a simulated ash loading process showed better PN removal efficiency than another used DPF that has only undergone ash removal treatment, or a new DPF that has not undergone any treatment, or a new DPF with simulated ash loading.

[0186] While preferred embodiments of the invention have been described in detail herein, those skilled in the art will understand that changes may be made without departing from the scope of the invention or the appended claims. For the avoidance of doubt, the entire contents of all documents referenced herein are incorporated herein by reference.

Claims

1. A method for treating a used particulate filter, the method comprising: Remove particles from the particulate filter, wherein the particles include ash; and After particle removal, simulated ash and / or a precursor of simulated ash are introduced into the inlet channel of the particulate filter, wherein the simulated ash and / or the precursor are provided in an amount of not less than 0.05 grams per liter of particulate filter volume; the simulated ash has a porous structure capable of existing at a temperature not less than 300°C; and the simulated ash and / or its precursor has a particle size of 0.01 micrometers to 1000 micrometers.

2. The method of claim 1, wherein, The particulate filter is used to remove exhaust particles generated by the internal combustion engine.

3. The method according to any of the preceding claims, wherein, The used particulate filter has at least one of the following: a specific time period since the last treatment of the particulate filter, a specific mileage of the vehicle with the particulate filter, a specific regeneration frequency of the particulate filter within the specific time period, a specific horsepower of the vehicle with the particulate filter, a warning from an indicator light, a signal from a sensor, a specific back pressure of the particulate filter, and a specific load of particulate matter.

4. The method according to any one of the preceding claims, wherein, The particulate removal process includes applying a gas flow and / or a liquid flow to the outlet and / or inlet of the particulate filter.

5. The method according to claim 4, wherein, The particulate removal process includes exposing the particulate filter to temperatures ranging from 450°C to 850°C.

6. The method according to claim 4 or 5, wherein, The gas flow is provided at a pressure of 1-15 bar and / or a flow rate of 100-10000 liters per minute.

7. The method according to any one of the preceding claims, wherein, The step of introducing simulated ash includes introducing droplets and / or solid particles of simulated ash and / or its precursors into the channel of the particle filter through the inlet end of the particle filter.

8. The method according to any one of the preceding claims, wherein, The steps of introducing simulated ash include: introducing simulated ash into the channels of the particulate filter and subjecting the particulate filter to further heat treatment.

9. The method according to any one of the preceding claims, wherein, The step of introducing simulated ash includes introducing a precursor into the channel of the particulate filter and further processing the particulate filter to convert the precursor into simulated ash.

10. The method according to claim 7, wherein, at a flow rate of 100-10000 m 3 / h.

11. The method according to claim 7 or 10, wherein, The droplets and / or solid particles are introduced into the particulate filter by blowing, suction, spraying and / or coating.

12. A system for treating a used particulate filter by the method according to any one of claims 1-11, the system comprising: A cleaning unit having an applicator for a gas flow and / or a liquid flow, the applicator being configured to remove particles accumulated in a particulate filter, wherein the particles include ash; and A guiding unit configured to provide simulated ash and / or a precursor of simulated ash into the channels of the particulate filter after particle removal.

13. The system of claim 12 further includes a detection unit for evaluating the particulate filter using processing criteria.

14. The system of claim 12 or 13 further includes a control unit configured to deactivate the cleaning unit and / or the guiding unit when the step of determining that the removal of particles from the particulate filter and / or the introduction of simulated ash into the inlet channel of the particulate filter is completed.

15. A method for manufacturing a particulate filter, comprising: Provide particulate filters with a honeycomb structure; Simulated ash is introduced into the inlet channel of the honeycomb structure; At least a portion of the simulated ash and / or particles are removed from the inlet channel of the honeycomb structure; as well as The simulated ash and / or its precursor are introduced again into the inlet channel of the honeycomb structure, wherein the simulated ash and / or precursor is provided at a rate of not less than 0.05 grams per liter of particulate filter; the simulated ash has a porous structure capable of existing at a temperature not less than 300°C; and the simulated ash and / or its precursor has a particle size of 0.01 micrometers to 1000 micrometers.

16. A system for manufacturing a particulate filter using the method of claim 15, the system comprising: A guiding unit configured to provide simulated ash and / or particles on the inner surface of the inlet channel of a honeycomb structure to be used in a particulate filter; as well as A cleaning unit having an applicator for gas flow and / or liquid flow, the cleaning unit being configured to remove simulated ash and / or particles from the inlet channel of the honeycomb structure.

Images