Configuration for decomposing nitrogen oxides in a gas stream and method for using the configuration

A method for decomposing nitrogen oxides in a gas stream flow, which comprises:

• placing a plurality of catalytic converters including a first catalytic converter and a second catalytic converter one behind the other in a flow direction of a gag stream, each of the plurality of catalytic converters having a honeycomb structure with a multiplicity of parallel cells, each of the plurality of catalytic converters also having a predetermined cell density of the parallel cells and a predetermined average level of catalytic activity for decomposing nitrogen oxides defined by a percentage of weight of a catalytically active agent in a respective catalytic converter, the predetermined cell density of the second catalytic converter being lower than the predetermined cell density of the first catalytic converter, and the predetermined average level of catalytic activity of the second catalytic converter being higher than the predetermined average level of catalytic activity of the first catalytic converter;
• and
• processing the gas stream discharged as exhaust gas from a combustion drive unit through the plurality of catalytic converters for decomposing nitrogen oxides in the gas stream, the gas stream having a temperature fluctuating between about 170° C. and about 500° C.