摘要:
A system for NOx reduction in combustion gases, especially from diesel engines, incorporates an oxidation catalyst to convert at least a portion of NO to NO2, a particulate filter, a source of reductant such as NH3 and an SCR catalyst. Considerable improvements in NOx conversion are observed.
摘要:
In the control of pollutants such as NOx in the exhaust gases from internal combustion engines, ozone is reacted with NO to form NO2, which is then reduced catalytically to N2.
摘要翻译:在控制来自内燃机的废气中的NO x NO x等污染物时,臭氧与NO反应形成NO 2,然后将其催化还原为N 2, SUB> 2 SUB>。
摘要:
A filter for filtering particulate matter (PM) from exhaust gas emitted from a compression ignition engine, which filter comprising a porous substrate having inlet surfaces and outlet surfaces, wherein the inlet surfaces are separated from the outlet surfaces by a porous structure containing pores of a first mean pore size, wherein the porous substrate is coated with a wash coat comprising a plurality of solid particles comprising a molecular sieve promoted with at least one metal wherein the porous structure of the wash coated porous substrate contains pores of a second mean pore size, and wherein the second mean pore size is less than the first mean pore size.
摘要:
An extruded honeycomb catalyst for nitrogen oxide reduction according to the selective catalytic reduction (SCR) method in exhaust gases from motor vehicles includes an extruded active carrier in honeycomb form having a first SCR catalytically active component and with a plurality of channels through which the exhaust gas flows during operation, and a washcoat coating having a second SCR catalytically active component being applied to the extruded body, wherein the first SCR catalytically active component and the second SCR catalytically active component are each independently one of: (i) vanadium catalyst with vanadium as catalytically active component; (ii) mixed-oxide catalyst with one or more oxides, in particular those of transition metals or lanthanides as catalytically active component; and (iii) an Fe- or a Cu-zeolite catalyst.
摘要:
An exhaust system for a vehicular lean burn internal combustion engine that emits oxides of nitrogen (NOx) and particulate matter (PM) is disclosed. The system comprises a NOx reduction catalyst for reducing NOx in the presence of a nitrogenous reductant, means for introducing the nitrogenous reductant into a flowing exhaust gas, a filter for removing PM from exhaust gas flowing in the exhaust system and a low pressure exhaust gas recirculation (EGR) circuit for connecting the exhaust system downstream of the filter to an air intake of the engine. The EGR circuit comprises an ammonia oxidation catalyst.
摘要:
Provided is a catalyst comprising (a) a zeolite material having a mean crystal size of at least about 0.5 μm, having a CHA framework that contains silicon and aluminum, and having a silica-to-alumina mole ratio (SAR) of about 10 to about 25; and (b) an extra-framework promoter metal (M) disposed in said zeolite material as free and/or exchanged metal, wherein the extra-framework promoter metal is copper, iron, and mixtures thereof, and is present in a promoter metal-to-aluminum atomic ratio (M:Al) of about 0.10 to about 0.24 based on the framework aluminum; and optionally comprising (c) at least about 1 weight percent of cerium in said zeolite material, based on the total weight of the zeolite, wherein said cerium is present in a form selected from exchanged cerium ions, monomeric ceria, oligomeric ceria, and combinations thereof, provided that said oligomeric ceria has a particle size of less than 5 μm.
摘要:
Provided is a wall-flow filter coated with an SCR catalyst composition, wherein the catalyst composition contains transition metal promoted molecular sieve crystals, and wherein (i) the crystals have a mean crystalline size of about 0.5 μm to about 15 μm, (ii) the crystals are present in said composition as individual crystals, agglomerations having a mean particle size of less than about 15 μm, or a combination of said individual crystals and said agglomerations; and (iii) said molecular sieve is an aluminosilicate or a silico-aluminophosphate of a Framework Type having a maximum ring size of eight tetrahedral atoms.
摘要:
Provided is a catalyst comprising (a) a zeolite material having a mean crystal size of at least about 0.5 μm, having a CHA framework that contains silicon and aluminum, and having a silica-to-alumina mole ratio (SAR) of about 10 to about 25; and (b) an extra-framework promoter metal (M) disposed in said zeolite material as free and/or exchanged metal, wherein the extra-framework promoter metal is copper, iron, and mixtures thereof, and is present in a promoter metal-to-aluminum atomic ratio (M:Al) of about 0.10 to about 0.24 based on the framework aluminum; and optionally comprising (c) at least about 1 weight percent of cerium in said zeolite material, based on the total weight of the zeolite, wherein said cerium is present in a form selected from exchanged cerium ions, monomeric ceria, oligomeric ceria, and combinations thereof, provided that said oligomeric ceria has a particle size of less than 5 μm.
摘要:
A filter for filtering particulate matter (PM) from exhaust gas emitted from a compression ignition engine, which filter comprising a porous substrate having inlet surfaces and outlet surfaces, wherein the inlet surfaces are separated from the outlet surfaces by a porous structure containing pores of a first mean pore size, wherein the porous substrate is coated with a wash coat comprising a plurality of solid particles comprising a molecular sieve promoted with at least one metal wherein the porous structure of the wash coated porous substrate contains pores of a second mean pore size, and wherein the second mean pore size is less than the first mean pore size.
摘要:
A system for NOx reduction in combustion gases, especially from diesel engines, incorporates an oxidation catalyst to convert at least a portion of NO to NO2, a particulate filter, a source of reductant such as NH3 and an SCR catalyst. Considerable improvements in NOx conversion are observed.