Reduction of N2O emissions from fluidized bed combustion with afterburning

One way to reduce N2O emissions is to raise the temperature of the combustion gases. This can be done in the combustion chamber during conventional operation, but also through injection of a secondary fuel, preferably in a separate combustion chamber. This paper reports investigations at the 12 MW circulating fluidized bed boiler at Chalmers University of Technology, where in the absence of a seperate combustion chamber, secondary fuel was injected into the primary cyclone. While the gas temperature was increased in the cyclone. While the gas temperature was increased in the cyclone, normal operation was maintained in the furnace. A temperature increase of 150 deg C was sufficient to remove almost all N2O