Optimization of emissions from fluidized bed boilers

The experiences of emissions of SO₂, NO_x and N₂O from fluidized bed boilers obtained from extensive measurements by the Department of Energy Conversion, Chalmers University of Technology, are briefly summarized. In addition, results from secondary methods to reduce NO and N₂O emissions are shown. With this background, possibilities for decreasing the N₂O emissions by the optimization of boiler parameters involving the use of secondary methods are discussed. The problem lies in the increase in the SO₂ and NO emissions when a measure is taken to reduce the N₂O emission. In particular, the influence of excess air and temperature is considered in comparison with selective noncatalytic reduction of NO.