NITRIC OXIDE REDUCTION OVER SEWAGE SLUDGE AND COAL CHARS AT CONDITIONS RELEVANT TO STAGED FLUIDIZED BED COMBUSTION

摘要

The de-NO_x potential of coal and of dried and pelletized sewage sludge, a waste-derived fuel candidate for cofiring with coal, is assessed. The experimental procedure is based on operation of a bench scale fluidized bed reactor where NO-doped nitrogen is contacted with batches of the fuel. A second type of experiment has been purposely designed to assess the loss of reactivity of chars toward gasification by NO_x as char is heat-treated for pre-set times at temperatures typical of fluidized bed combustion. A simple phenomenological model is developed to shed light on the basic features of the interaction between heterogeneous char-NO_x reaction and thermal annealing of the char.