SELECTIVE REDUCTION OF NOX BY NH3 OVER HONEYCOMB DENOXING CATALYSTS

Data are presented for the effects of feed composition (O2, NO(x), NH3 , H2O, SO2 concentrations) and of the operating conditions (area veloc ity, reaction temperature, and Re number) on the NO(x) removal efficie ncy over commercial-type honeycomb DeNOxing catalysts with different c ompositions and geometric characteristics. All of these data are expla ined by a Rideal type kinetic expression, derived assuming reaction be tween strongly adsorbed ammonia and gaseous or weakly bonded NO. The s ignificance of interphase and intraparticle diffusion limitations is d iscussed, and a comprehensive model of the SCR monolith reactor is ill ustrated which fully accounts for both external and internal transport of the reactants as well as for the effects of the operating variable s and of the feed composition under representative SCR conditions.