Hydrocarbon selective catalytic reduction catalyst for NOx emissions control
AssigneeBASF SE
InventorsHoward Furbeck, Gerald Koermer, Ahmad Moini
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Abstract
The present disclosure provides an AgBi catalyst over alumina suitable for performing hydrocarbon selective catalytic reduction (HC-SCR).
Claims20
A hydrocarbon selective catalytic reduction catalyst for hydrocarbon selective catalytic reduction of NOx in an exhaust stream, the catalyst comprising:
- a) about 0.1 to about 5.0 weight percent silver on an Ag2O basis;
- b) about 0.0075 to about 0.3 weight percent bismuth on a Bi2O3 basis;
- and
- c) about 94.7 to about 99.8925 weight percent alumina,
- wherein the hydrocarbon selective catalytic reduction catalyst is capable of reducing at least about 50% of NOx to N2 in the exhaust stream, and
- wherein at least about 95 weight percent of the silver in the catalyst has a non-zero oxidation state.
A method for preparing a hydrocarbon selective catalytic reduction catalyst for hydrocarbon selective catalytic reduction of NOx in an exhaust stream including about 0.1 to about 5.0 weight percent silver on an Ag2O basis, about 0.0075 to about 0.3 weight percent bismuth on a Bi2O3 basis;
- and about 94.6 to about 99.8925 weight percent alumina, wherein the hydrocarbon selective catalytic reduction catalyst is ca able of reducing at least about 50% of NO to N in the exhaust stream and wherein at least about 95 weight percent of the silver in the catalyst has a non-zero oxidation state, said method comprising:
- a) mixing a known volume of an AgNO3 solution of known molarity with a known volume of a Bi(NO3)3 solution of known molarity to form a mixed solution;
- b) adding the mixed solution to a known mass of alumina having a known incipient wetness to form a slurry,
- c) optionally, adding additional water to said slurry to achieve said incipient wetness;
- d) drying said slurry at about 90° C. for about 16 hours in a convection oven to give a dry powder;
- e) calcining said dry powder at about 540° C. for about 2 hours to give calcined material;
- and
- f) steam aging said calcined material at about 650° C. for about 16 hours with about 10% steam in air.
A monolith comprising a hydrocarbon selective catalytic reduction catalyst for hydrocarbon selective catalytic reduction of NOx in an exhaust stream, the catalyst having about 0.1 to about 5.0 weight percent silver on an Ag2O basis, about 0.0075 to about 0.3 weight percent bismuth on a Bi2O3 basis;
- and about 94.6 to about 99.8925 weight percent alumina,
- wherein the hydrocarbon selective catalytic reduction catalyst is capable of reducing at least about 50% of NOx to N2 in the exhaust stream, and
- wherein at least about 95 weight percent of the silver in the catalyst has a non-zero oxidation state.
A method for hydrocarbon selective catalytic reduction of NOx in an exhaust stream, said method comprising:
- a) contacting an exhaust stream including NOx with a hydrocarbon selective catalytic reduction catalyst at a first temperature, said catalyst having about 0.1 to about 5.0 weight percent silver on an Ag2O basis, about 0.0075 to about 0.3 weight percent bismuth on a Bi2O3 basis;
- and about 94.6 to about 99.8925 weight percent alumina;
- and
- b) reducing at least about 50% of said NOx to N2 with said catalyst thereby reducing NOx in the exhaust stream;
- wherein at least about 95 weight percent of the silver in the catalyst has a non-zero oxidation state.
Dependencies are inferred from the claim text.