Numerical simulation of selective catalytic reduction of NO and SO2 oxidation in monolith catalyst

Abstract A three-dimensional model that combined the selective catalytic reduction (SCR) of NO with ammonia and SO 2 oxidation reactions over monolith honeycomb catalyst was established to study the effects of catalyst structure and operating parameters on NO reduction and SO 2 oxidation. The model was to proved to be valid by experimental data. Simulation results showed that the SCR reaction only took place within a thin layer ( ca. 0.2 mm) of the catalyst wall surface, whereas SO 3 generated via SO 2 oxidation accumulated throughout the entire wall. The effects of typical operating parameters, i.e., space velocity, temperature, feed concentrations of NO, NH 3 and SO 2 were studied. Temperature and gas velocity were found to be the major influencing factors on SO 2 oxidation. A strategy for monolith catalyst struction optimization, i.e., using thin-walled catalyst was proposed on the basis of these results.