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US 6,569,394 B2Granted
Catalyst body and process for breaking down nitrogen oxides
AssigneeSiemens Aktiengesellschaft
InventorsStefan Fischer, Günther Pajonk, Frank Witzel
Life of this patent
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Abstract
A gas stream that contains nitrogen oxides is passed, in the presence of a reducing agent, over a catalyst body with an active material that contains a zeolite and titanium dioxide. The zeolite is a hydrogen-ion-exchanged, acid zeolite. Even at temperatures above 450° C., the nitrogen oxides contained are still effectively converted into nitrogen and water.
Claims7
A catalyst body for breaking down nitrogen oxide in a presence of a reducing agent, the catalyst body comprising:
- an active material containing a hydrogen-ion-exchanged, acid zeolite and an active component, said active material contains 40-60% by weight of said zeolite and 40-60% by weight of said active component, said active component contains 70-95% by weight of titanium dioxide, 2-30% by weight of tungsten trioxide, 0.1-10% by weight of aluminum oxide and 0.1-10% by weight of silicon dioxide.
A process for breaking down nitrogen oxides, which comprises the steps of:
- providing a catalyst body containing an active material having a hydrogen-ion-exchanged, acid zeolite and an active component, the active material contains 40-60% by weight of the zeolite and 40-60% by weight of the active component, the active component contains 70-95% by weight of titanium dioxide, 2-30% by weight of tungsten trioxide, 0.1-10% by weight of aluminum oxide and 0.1-10% by weight of silicon dioxide;
- and
- passing a gas stream containing the nitrogen oxides, in a presence of a reducing agent, through the catalyst body, and converting the nitrogen oxides into nitrogen and water.
Dependencies are inferred from the claim text.