SNCR - Selective Non Catalyst Reduction

Larger powerplants such as biomass powerplants also have to meet the limit values set for nitrogen oxides in the local legislation. The use of SCR is not possible because of the high temperature of the exhaust gases (approx. 900 / 950˚C). For these installations we apply a selective non catalyst reaction. By directly injecting urea or ammonia in the furnace the NOx is transformed to N2. The position of injecting the reagent is crucial. To early injecting results in burning of the reagent. To late injecting will prevent the reagent to react completely. This introduces NH3 slip which will result in deposition in the boiler which is highly unwanted.