摘要:
Catalyst articles having an ammonia slip catalyst (ASC) comprising a blend of platinum on a support with low ammonia storage and a first SCR catalyst, and a second catalyst, such as a diesel oxidation catalyst, a diesel exotherm catalyst (DEC), a NOx absorber, a selective catalytic reduction/passive NOx adsorber (SCR/PNA), a cold-start catalyst (CSC) or a three-way catalyst (TWC) are disclosed. The catalyst articles can also contain one or two additional SCR catalysts. The catalysts can be present in one of various configurations. The catalytic articles are useful for selective catalytic reduction (SCR) of NOx in exhaust gases and in reducing the amount of ammonia slip. Methods of using the catalytic articles in an SCR process, where the amount of ammonia slip is reduced, are also described.
摘要:
Provided is a catalytic article comprising (a) a flow through honeycomb substrate having channel walls; (b) a first NH3-SCR catalyst composition coated on and/or within the channel walls in a first zone; and (c) a second NH3-SCR catalyst composition coated on and/or within the channel walls in a second zone, provided that the first zone is upstream of the second zone and the first and second zones are adjacent or at least partially overlap; and wherein the first NH3-SCR catalyst comprises a first copper loaded molecular sieve having a copper to aluminum atomic ratio of about 0.1 to 0.375 and the second NH3-SCR catalyst comprises a second copper loaded molecular sieve having a copper-to-aluminum atomic ratio of about 0.3 to about 0.6.
摘要:
Catalyst articles having a first zone containing a first SCR catalyst and a second zone containing an ammonia slip catalyst (ASC), where the ammonia slip catalyst contains a second SCR catalyst and an oxidation catalyst, and the ASC has DOC functionality, where the first zone is located on the inlet side of the substrate and the second zone is located in the outlet side of the substrate are disclosed. The catalytic articles are useful for selective catalytic reduction (SCR) of NOx in exhaust gases, in reducing the amount of ammonia slip and in oxidizing organic residues. Exhaust systems containing the catalyst articles and methods of using the catalytic articles in an SCR process, where the amount of ammonia slip is reduced and hydrocarbon are oxidized by the ASC catalyst, are also described.
摘要:
A catalytic article having a flow-through substrate having an inlet, an outlet, and an axial length; an SCR zone containing a first SCR catalyst; and an oxidation zone containing (a) an ASC zone and a DOC zone or (b) a mixed ASC and DOC zone, where the oxidation zone contains an ammonia oxidation catalyst and a DOC catalyst, the SCR zone is positioned on the substrate from the inlet end and extends less than the axial length of the substrate from the inlet, the DOC zone or the mixed ASC and DOC zone is position on the substrate from the outlet end, and when the DOC zone is present, the ASC zone is located between the SCR zone and the DOC zone. In other catalytic articles, the ASC zone further comprises a DEC catalyst. Methods of using the catalytic articles in an SCR process, where the amount of ammonia slip is reduced, are also described.
摘要:
A catalyst for oxidising ammonia comprises a selective catalytic reduction (SCR) catalyst and a composite heterogeneous extruded honeycomb having longitudinally extending parallel channels, which channels being defined in part by channel walls having a total longitudinal length, wherein the channel walls comprise a pore structure including a periodic arrangement of porous cells embedded in an inorganic matrix component, at least some of which porous cells are defined at least in part by an active interface layer of a catalytically active material comprising a precious metal supported on particles of a support material.
摘要:
Catalyst articles having an ammonia slip catalyst (ASC) comprising a blend of platinum on a support with low ammonia storage and a first SCR catalyst, and a second catalyst, such as a diesel oxidation catalyst, a diesel exotherm catalyst (DEC), a NOx absorber, a selective catalytic reduction/passive NOx adsorber (SCR/PNA), a cold-start catalyst (CSC) or a three-way catalyst (TWC) are disclosed. The catalyst articles can also contain one or two additional SCR catalysts. The catalysts can be present in one of various configurations. The catalytic articles are useful for selective catalytic reduction (SCR) of NOx in exhaust gases and in reducing the amount of ammonia slip. Methods of using the catalytic articles in an SCR process, where the amount of ammonia slip is reduced, are also described.
摘要:
A catalyst article including a substrate with an inlet end and an outlet end, a first zone and a second zone, where the first zone comprises: a) an ammonia slip catalyst (ASC) bottom layer comprising a platinum group metal on a support; and b) an SCR layer comprising a second SCR catalyst, the SCR layer located over the ASC bottom layer; where the second zone comprises a catalyst (“second zone catalyst”) selected from the group consisting of a diesel oxidation catalyst (DOC) and a diesel exotherm catalyst (DEC); wherein the ASC bottom layer extends into the second zone; and where the first zone is located upstream of the second zone. The ASC bottom layer may include a blend of: (1) the platinum group metal on a support and (2) a first SCR catalyst.
摘要:
A catalytic article having a flow-through substrate having an inlet, an outlet, and an axial length; an SCR zone containing a first SCR catalyst; and an oxidation zone containing (a) an ASC zone and a DOC zone or (b) a mixed ASC and DOC zone, where the oxidation zone contains an ammonia oxidation catalyst and a DOC catalyst, the SCR zone is positioned on the substrate from the inlet end and extends less than the axial length of the substrate from the inlet, the DOC zone or the mixed ASC and DOC zone is position on the substrate from the outlet end, and when the DOC zone is present, the ASC zone is located between the SCR zone and the DOC zone. In other catalytic articles, the ASC zone further comprises a DEC catalyst. Methods of using the catalytic articles in an SCR process, where the amount of ammonia slip is reduced, are also described.
摘要:
Catalyst articles having an ammonia slip catalyst (ASC) comprising a blend of platinum on a support with low ammonia storage and a first SCR catalyst, and a second catalyst, such as a diesel oxidation catalyst, a diesel exotherm catalyst (DEC), a NOx absorber, a selective catalytic reduction/passive NOx adsorber (SCR/PNA), a cold-start catalyst (CSC) or a three-way catalyst (TWC) are disclosed. The catalyst articles can also contain one or two additional SCR catalysts. The catalysts can be present in one of various configurations. The catalytic articles are useful for selective catalytic reduction (SCR) of NOx in exhaust gases and in reducing the amount of ammonia slip. Methods of using the catalytic articles in an SCR process, where the amount of ammonia slip is reduced, are also described.
摘要:
A catalyst for oxidising ammonia comprises a selective catalytic reduction (SCR) catalyst and a composite heterogeneous extruded honeycomb having longitudinally extending parallel channels, which channels being defined in part by channel walls having a total longitudinal length, wherein the channel walls comprise a pore structure including a periodic arrangement of porous cells embedded in an inorganic matrix component, at least some of which porous cells are defined at least in part by an active interface layer of a catalytically active material comprising a precious metal supported on particles of a support material.