Primary Measures to Reduce the Emissions of Nitrogen Oxide in Circulating Fluidized Bed Boilers

Other conference contribution, 1987

During the combustion of coal in a circulating fluidized bed boiler the conversion of the fuel­bond nitrogen to either nitrogen oxides or nitro­gen can be influenced by design and operational measures. The paper gives a summary of results obtained in a series of tests on a 40 MW circulating fluid­ized bed boiler in Nykoping, designed by Gota­verken Energy. In this commercial boiler it was not possible to study the influence of primary to secondary air addition independent of the bed temperature. For this reason, a smaller boiler designed by the same manufacturer was adapted to permit independent variations of the primary air ratio and the bed temperature. The results from the 40 MW and the 8 MW boilers are compared and the influence of the distribution of the air supply and of the bed temperature on the reduction of nitrogen oxide emissions are dis­cussed.