Catalyst promoters in vanadium-free mobile catalyst
AssigneeCristal USA Inc.
InventorSteven M. Augustine
Life of this patent
Estimating the term…
Abstract
Low temperature activity of a vanadium-free selective catalytic reduction catalyst is provided by a mixed metal oxide support containing oxides of titanium and zirconium, the support having a promoter deposited on the surface of the mixed metal oxide support, and further having an active catalyst component deposited over the promoter on the mixed metal oxide support surface. Suitable promoters include oxides of silicon, boron, aluminum, cerium, iron, chromium, cobalt, nickel, copper, tin, silver, niobium, lanthanum, titanium, and combinations thereof. Suitable active catalyst components include oxides of manganese, iron and cerium.
Claims27
A catalyst composition comprising:
- a mixed metal oxide support containing oxides of titanium and zirconium and having a mixed metal oxide support surface;
- a promoter selected from the group consisting of oxides of silicon, boron, aluminum, cerium, iron, chromium, cobalt, nickel, copper, tin, silver, niobium, lanthanum, titanium, and combinations thereof, wherein the promoter is deposited on the mixed metal oxide support surface prior to any calcination of the mixed metal oxide support surface, providing a promoter-containing support surface;
- and
- an active catalyst component selected from the group consisting of oxides of manganese, iron and cerium, the active catalyst component deposited on the promoter-containing support surface prior to any calcination of the promoter-containing support surface.
A method of making a catalyst for selective catalytic reduction of nitrogen oxide, the method comprising the following steps:
- contacting a mixed metal oxide support with promoter precursors, the mixed metal oxide support containing titanium oxide and zirconium oxide and having a surface, thereby depositing the promoter on the mixed metal oxide support surface, prior to any calcination of the mixed metal oxide support surface, to form a promoter-containing support surface, the promoter selected from the group consisting of oxides of boron, silicon, aluminum, cerium, iron, chromium, cobalt, nickel, copper, tin, silver, niobium, lanthanum, titanium, and combinations thereof, the promoter present in a range of from about 0.01 wt % to about 15 wt % of the mixed metal oxide;
- and
- depositing an outer layer of an active catalyst component onto the promoter-containing support surface, prior to any calcination of the promoter-containing support surface, wherein the active catalyst component is selected from the group consisting of manganese oxide, iron oxide and cerium oxide, and the active catalyst component is present in an amount in a range of from about 0.05 mol % to about 20 mol % of the mixed metal oxide support.
A method for improving the low temperature conversion activity of manganese-containing mixed metal oxide catalysts used for selective catalytic reduction of nitrogen oxides with ammonia, the method comprising:
- providing a mixed metal oxide support containing titanium oxide and zirconium oxide;
- and
- depositing a promoter onto a surface of the mixed metal oxide support, prior to any calcination of the mixed metal oxide support surface, the promoter selected from the group consisting of oxides of silicon, boron, aluminum, cerium, iron, chromium, cobalt, nickel, copper, tin, silver, niobium, lanthanum, titanium, and combinations thereof, thereby forming a promoter-containing mixed metal oxide support surface;
- and
- depositing manganese oxide onto the promoter-containing mixed metal oxide support surface prior to any calcination of the promoter-containing mixed metal oxide support surface;
- wherein the quantities of promoter and manganese oxide deposited are controlled to provide low temperature catalytic activity.
A method for selective reduction of nitrogen oxides with ammonia, wherein the nitrogen oxides are present in a gas stream, the method comprising:
- contacting the gas stream with ammonia in the presence of a catalyst, the catalyst comprising:
- a mixed metal oxide support containing oxides of titanium and zirconium;
- and
- a promoter selected from the group consisting of oxides of silicon, boron, aluminum, cerium, iron, chromium, cobalt, nickel, copper, tin, silver, niobium, lanthanum, and combinations thereof, the promoter deposited on a surface of the mixed metal oxide support, prior to any calcination of the mixed metal oxide support surface, to provide a promoter-containing mixed metal oxide support surface;
- and
- an active catalyst component deposited on the promoter-containing mixed metal oxide support surface prior to any calcination of the promoter-containing mixed metal oxide support surface, wherein the active catalyst component is selected from the group consisting manganese oxide, iron oxide and cerium oxide.
Dependencies are inferred from the claim text.