Abstract: An exhaust gas cleaning system includes a pyrolysation channel, a mixing channel downstream of the pyrolysation channel and a reaction channel downstream of the mixing channel. An atomizing nozzle is provided for injecting into the pyrolysation channel an atomized mixture of compressed air and a dilute urea solution. The compressed air and dilute urea solution contacts the exhaust gas stream in the pyrolysation channel wherein the urea decomposes into ammonium and carbon dioxide. Mixers are provided in the mixing channel for forming a homogeneous mixture of the ammonium and carbon dioxide with the exhaust gas. The reaction channel downstream of the mixing channel is provided with at least two catalysts for contacting the homogeneous mixture and removing effluents therefrom.

Abstract: In a process for cleaning the exhaust gases from combustion installations, a dilute urea solution prepared in a reagent tank (20) is introduced into the hot exhaust gas flow (30) of differing concentrations and is finely sprayed in the direction of the exhaust gas flow. After decomposition of the urea in a pyrolysation channel (14), the exhaust gas flow (30) is homogeneously mixed in-line by a mixer located in a mixing channel (16). In a subsequent in-line reaction channel (18), the reducible exhaust gas constituents are converted into non-toxic gases in at least one selective reduction catalyst which does not contain zeolite (36), then, dependent on the installation, the oxidizable exhaust gas components are converted into non-toxic gases without reagent in at least one oxidation catalyst (38) to produce a virtually complete reaction.