Ammonia Addition for NOx Reduction in Fluidized Bed Boilers

Ammonia is added to the gases in the combustion chamber of fluidized bed briilers in order to investigate its effect ori the emission of nitrogen oxides. A stationary and a circulating fluidized bed boiler are used. In the sta­tionary fluidized bed boiler an addition corresponding to a (NH3/NOexit-molar ratio of 3 gives a 50% reduction of the NO emission. Larger doses lead to escape of ammonia and other disadvantages. In the circulating fluidized bed boiler no effect from injection of ammonia into the combustion chamber is noted. The ammonia is decomposed. If NH3 is to be used in circulating fluidized bed boilers it should be introduced in the particle-free gas after the particle separator