and methods for continuously operating a urea-scr system, for reducing the amount of so3 in a combustion exhaust gas, for reducing ammonium bisulfate formation and scr catalyst deactivation in a urea-scr system and for increase the efficiency of a system that produces combustion exhaust gas.

摘要

Systems and methods for continuous operation of a urea-scr system at low temperatures (200-350 ° C) in the presence of high sox-containing flue gas are described. The methods comprise introducing a urea solution and a no2 forming compound, preferably an alkaline earth metal nitrate, into an exhaust stream before the exhaust stream contacts a scr catalyst.