CFD analysis of influencing factors on SCR denitration efficiency of sintering flue gas based on response surface methodology

Abstract

Selective catalytic reduction（SCR） technology is the key technology of flue gas denitration. SCR reactors are the systems contributing to pollution-free emission if they function properly. In order to study SCR denitration chemical reaction simulation and optimize the denitration effect, the CFD analysis of SCR reactor was carried out. The realizable k-ϵ turbulence model, component transport model and chemical reaction model were used to simulate the SCR denitration reactor. Based on the response surface methodology (RSM), the effects of three factors on the denitration efficiency were studied, including catalyst inlet gas velocity, reaction temperature and NH3/NO molar ratio. The quadratic multinomial regression model of three factors affecting the denitration efficiency was established. In addition, the structure of hot air duct and guiding plate were optimized based on the non-uniform inlet temperature. The results showed that: three factors had a significant impact on the denitration efficiency, and the interaction of catalyst inlet gas velocity and reaction temperature is the most significant; the structure optimization of hot air duct and guiding plate can improve the denitration efficiency and reduce outlet NO concentration relative standard deviation, and avoid catalyst abrasion. In this paper, a suitable numerical simulation model is proposed for SCR denitration reaction, and the consideration of non-uniform inlet temperature and the proposition about taking relative standard deviation of NO concentration at the outlet as an optimization index contribute to a more practical and more reasonable structure optimization.