EMPIRICAL MODELING OF THE SELECTIVE NONCATALYTIC REDUCTION OF NO - COMPARISON WITH LARGE-SCALE EXPERIMENTS AND DETAILED KINETIC MODELING

An empirical model for the selective non-catalytic reduction (SNR) of NO with NH3 as reductant is proposed. The model is based on two empiri cal reactions: one reaction describing the oxidation of NH3 to NO, and the other the reduction of NO by reaction with NH3 to N2. It is shown that the model describes the influence of the major parameters that c an be varied in the SNR process (injection temperature, temperature gr adient, residence time, amount of injected NH3 and amount of injected additive). The model predictions are compared to experiments carried o ut in a fluidized bed boiler and in a pilot plant using flue gas withd rawn from a coal fired utility boiler and it is compared with the kine tic model of Miller and Bowman (1989). When ideal mixing between the i njected NH3 and the flue gas can be assumed, as in the cyclone of the fluidized bed boiler, a good agreement between the model predictions a nd the experiments is obtained. The empirical model gives a better des cription of the result for a fluidized bed boiler than the kinetic mod el of Miller and Bowman (1989). In the coal fired pilot plant the mixi ng process is not ideal, this seems to influence the process performan ce.