Effect of mixing on NO removal in the selective noncatalytic reduction reaction process

Abstract

The effect of mixing of NH3 and NO on the selective noncatalytic reduction (SNCR) reaction was investigated using a bench-scale reactor. Three different experimental conditions were compared for the removal of NO in the bulk gas with NH3, a reducing agent, by means of mixing and contacting. The temperature that gave the highest NO removal efficiency was about 800°C when NH3 was injected with air or NH3 was premixed and air was injected. It is suggested that control of mixing of the reducing agent and the injection conditions could be a good way to increase NO removal efficiency as well as to lower the reaction temperature. When NH3 was injected with air, the NO removal efficiency increased with increasing injected air flow if the initial NO concentration was low, whereas for high NO concentrations, the NO removal efficiency slightly increased up to an injected air flow rate of 100 ml/min. A proposed mixed-flow model can be used as a prediction tool for the NO removal efficiency covering various conditions of the real SNCR process.