CATALYTIC SYSTEM FOR REMOVAL OF NITROGEN OXIDES FROM EXHAUST GASES, APPLICATION OF THE SPECIFIED CATALYTIC SYSTEM FOR TREATMENT OF EXHAUST GASES AND METHOD OF REMOVAL OF NITROGEN OXIDES TO NITROGEN

摘要

1. A catalytic system for the reduction of nitrogen oxides from exhaust gases, containing at least two catalyst layers, in which the first catalyst layer is iron beta zeolite, and the second catalyst layer lying downstream is silver, deposited on alumina. ! 2. The catalytic system according to claim 1, in addition, containing at least one inert layer of material between the first and second catalyst layers. ! 3. The catalytic system according to claim 1 or 2, in addition, containing a catalyst layer for the oxidation of ammonia, lying downstream than the second catalyst layer. ! 4. A method of reducing nitrogen oxides to nitrogen in the exhaust gas, comprising passing exhaust gas in the presence of a reducing agent through a catalytic system containing at least two catalyst layers, in which the first catalyst layer is iron beta zeolite and the second layer The catalyst lying downstream is silver deposited on alumina. ! 5. The method according to claim 4, where the reducing agent is selected from ammonia, urea, hydrogen, alkanes, alkenes and mixtures thereof. ! 6. The method according to claim 5, where the reducing agent is a mixture of hydrogen and ammonia. ! 7. The method according to claim 4, where the amount of silver in the second catalyst layer is from 0.5 to 5 wt.%. ! 8. The method according to claim 7, where the amount of silver is 1 wt.%. ! 9. The method according to claim 7, where the alumina is boehmite. ! 10. The method according to claim 4, further comprising providing at least one inert layer of material between the first and second catalyst layers. ! 11. The method according to claim 5, where ammonia �