Experimental investigation of N2O formation in selective non-catalytic NOx reduction processes performed in stoker boiler

Stoker fired boiler plants are common throughout Eastern Europe. Increasingly strict emission standards will require application of secondary NOx  abatement systems on such boilers. Yet operation of such systems, in addition to reducing NOx  emissions, may also lead to emission of undesirable substances, for example N2O. This paper presents results of experimental tests concerning N2O formation in the selective non-catalytic NOx  emission reduction process (SNCR) in a stoker boiler (WR 25 type). Obtained results lead to an unambiguous conclusion that there is a dependency between the NOx  and N2O concentrations in the exhaust gas when SNCR process is carried out in a coal-fired stoker boiler. Fulfilling new emission standards in the analysed equipment will require 40–50% reduction of NOx  concentration. It should be expected that in such a case the N2O emission will be approximately 55–60 mg/m3, with the NOx  to N2O conversion factor of about 40%