| 摘要 |
A device and a method are described for lowering the content of NOx and N2O in gases. The device comprises: A) a container (1) and, arranged therein, B) two reaction steps connected one after the other for removing NOx (DeNOx stage) by reducing NOx with a nitrogen-containing reducing agent and, downstream thereof, for removing N2O by catalytic decomposition of N2O to N2 and O2 (DeN2O stage), which each consist of one or more catalyst beds (7, 8) and through which the gas that is to be purified flows, wherein C) the at least one catalyst bed of the DeNOx stage (7) contains a catalyst for reducing NOx with nitrogen-containing reducing agents which catalyst contains zeolites doped with transition metals, including the lanthanides, D) the at least one catalyst bed of the DeN2O-stage (8) contains a catalyst for decomposing N2O into N2 and O2, which contains one or more catalytically active compounds of elements selected from groups 5 to 11 of the Periodic Table of the Elements with the exception of iron-doped zeolites, and E), upstream of the DeNOx stage (7), a device for introducing a nitrogen-containing reducing agent into the stream of the NOx and N2O-containing gas is provided. The combination used according to the invention of catalysts permits a very simple structure and a very economic operation of the reactor. |
