Numerical simulation on deflector structure optimization in SCR denitrification system for sintering flue gas

Nitrogen oxides (NOx) constitute the principal air pollutants, and the sintering process serving as the predominant source of NOx emissions in the iron and steel sector. Selective catalytic reduction (SCR) denitrification technology is widely used for flue gas denitrification, but due to the low temperature of the sintering flue gas and the uneven internal flow field, it brings challenges to SCR technology. In this study, numerical simulations were performed to analyze the impact of various deflectors configurations on flue gas velocity distribution and system resistance characteristics in the SCR denitrification system, based on its specific dimensions and operational data. Results show that introducing four deflectors at the initial bend yields the optimal performance, with a velocity standard deviation of 12.93% at the inlet of the first catalyst layer and an overall pressure drop of 641.5 Pa. And compared to other deflectors shapes, the straight-arc deflectors exhibit the lowest velocity standard deviation at 10.85%. The lowest relative velocity standard deviation of 10.8% was achieved when the deflectors at the second bend are parallel to the outer wall. And uniform-length deflectors at the second bend exhibited the lowest velocity standard deviation of 8.69%.