SELECTIVE CATALYTIC REDUCTION FILTER FOR REDUCING NITROUS OXIDE FORMATION AND METHODS OF USING THE SAME
First Claim
1. A selective catalytic reduction filter (SCRF) comprising:
- a wall-flow substrate defining inlet channels for receiving exhaust gas and outlet channels through which the exhaust gas exits, wherein the inlet channels and the outlet channels are connected to one another through porous walls of the inlet and outlet channels;
a first selective catalytic reduction (SCR) catalyst zone present in the inlet channels, wherein the first SCR catalyst zone has a first SCR catalyst loading and comprises a first SCR catalyst coating comprising an iron-exchanged zeolite; and
a second SCR catalyst zone present in the outlet channels, wherein the second SCR catalyst zone has a second SCR catalyst loading and comprises a second SCR catalyst coating comprising a copper-exchanged zeolite;
wherein the combined first SCR catalyst loading and the second SCR catalyst loading is less than or equal to about 200 g/l.
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Abstract
A selective catalytic reduction filter (SCRF) including a wall-flow substrate having inlet channels and outlet channels is provided. A first selective catalytic reduction (SCR) catalyst zone is present in the inlet channels, and a second SCR catalyst zone is present in the outlet channels. The first SCR catalyst zone includes an iron-exchanged zeolite catalyst, and the second SCR catalyst zone includes a copper-exchanged zeolite catalyst. Exhaust gas treatment systems including the SCRF and methods of reducing production of nitrous oxide (N2O) during selective catalytic reduction of an exhaust gas stream using the SCRF are also provided herein.
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20 Claims
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1. A selective catalytic reduction filter (SCRF) comprising:
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a wall-flow substrate defining inlet channels for receiving exhaust gas and outlet channels through which the exhaust gas exits, wherein the inlet channels and the outlet channels are connected to one another through porous walls of the inlet and outlet channels; a first selective catalytic reduction (SCR) catalyst zone present in the inlet channels, wherein the first SCR catalyst zone has a first SCR catalyst loading and comprises a first SCR catalyst coating comprising an iron-exchanged zeolite; and a second SCR catalyst zone present in the outlet channels, wherein the second SCR catalyst zone has a second SCR catalyst loading and comprises a second SCR catalyst coating comprising a copper-exchanged zeolite; wherein the combined first SCR catalyst loading and the second SCR catalyst loading is less than or equal to about 200 g/l. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. An exhaust gas treatment system comprising:
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an oxidation catalyst (OC) unit for receiving exhaust gas; a selective catalytic reduction filter (SCRF) in fluid communication with the OC unit to receive exhaust gas flow therefrom, wherein the SCRF comprises; a wall-flow substrate defining inlet channels for receiving the exhaust gas flow from the OC unit and outlet channels through which the exhaust gas flow exits, wherein the inlet channels and the outlet channels are connected to one another through porous walls of the inlet and outlet channels; a first SCR catalyst zone present in the inlet channels, wherein the first SCR catalyst zone has a first SCR catalyst loading and comprises a first SCR catalyst coating comprising an iron-exchanged zeolite and optionally, a binder; and a second SCR catalyst zone present in the outlet channels, wherein the second SCR catalyst zone has a second SCR catalyst loading and comprises a second SCR catalyst coating comprising a copper-exchanged zeolite and optionally, a binder; wherein the combined first SCR catalyst loading and the second SCR catalyst loading is less than or equal to about 200 g/l; and an injection device for injecting urea or ammonia into the exhaust gas flow. - View Dependent Claims (10, 11, 12, 13, 14, 15)
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16. A method for reducing production of nitrous oxide (N2O) during selective catalytic reduction of an exhaust gas stream comprising:
contacting the exhaust gas stream comprising nitrogen oxides (NOx) and ammonia (NH3) with a selective catalytic reduction filter (SCRF) and converting the nitrogen oxides to nitrogen (N2) and water (H2O) to produce a treated exhaust gas stream, wherein the SCRF comprises; a wall-flow substrate defining inlet channels for receiving the exhaust gas stream and ammonia and outlet channels through which the treated exhaust gas stream exits, wherein the inlet channels and the outlet channels are connected to one another through porous walls of the inlet and outlet channels; a first SCR catalyst zone present in the inlet channels, wherein the first SCR catalyst zone has a first SCR catalyst loading and comprises a first SCR catalyst coating comprising an iron-exchanged zeolite and optionally, a binder; and a second SCR catalyst zone present in the outlet channels, wherein the second SCR catalyst zone has a second SCR catalyst loading and comprises a second SCR catalyst coating comprising a copper-exchanged zeolite and optionally, a binder; wherein the combined first SCR catalyst loading and the second SCR catalyst loading is less than or equal to about 200 g/l. - View Dependent Claims (17, 18, 19, 20)
Specification