초록 ▼

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 contain

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.

대표청구항 ▼

1. 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

1. 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. 2. The catalyst body according to claim 1, wherein said active component contains 8-12% by weight of the tungsten trioxide. 3. The catalyst body according to claim 1, wherein said zeolite is selected from the group consisting of an USY zeolite, a Beta zeolite and a ZSM-5 zeolite. 4. The catalyst body according to claim 1, wherein said active material has a BET surface area of 30-150 m2/g and a pore volume, measured using a Hg penetration method, of 100-1000 ml/g. 5. 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. 6. The process according to claim 5, which comprises adding an aqueous urea solution to the gas stream as the reducing agent. 7. The process according to claim 5, which comprises passing the gas stream through the catalyst body at a temperature of 250-750° C.