NO emission control during sintering process
摘要
During the sintering process of iron ore, a large amount of nitrogen oxides is generated, for which there is currently no efficient and economical treatment process. Therefore, it is necessary to implement process control in sintering production to keep the mass concentration of NOx in sintering flue gas at a low level. Through industrial trials at sintering sites, methods such as correlation analysis, path analysis, and multiple linear regression were applied to analyze the influence of various factors on NO emissions during the sintering process. The results indicate that negative correlations exist between nitrogen monoxide (NO) emissions and negative pressure, permeability index, O2 concentration, CO concentration, and flue gas temperature. Conversely, positive correlations exist between NO emissions and dust concentration, water vapor volume fraction, and sintering bed speed. Among these factors, O2 concentration and dust concentration are identified as the most significant influencing factors on NO emissions. By analyzing the masses and modes of influence of different factors, the mechanisms of action of each factor were obtained. Specifically, O2 concentration, dust concentration, permeability index, CO concentration, and flue gas temperature play a direct dominant role in NO emissions during the sintering process, while water vapor volume fraction, sintering trolley speed, and negative pressure have an indirect effect. A predictive model for NO mass concentration in flue gas was established with an accuracy rate of 91.6%, showing consistent overall trends with actual values. Finally, denitrification strategies for sintering industrial production were proposed, along with prospects for preliminary denitrification of sintering flue gas using fluidized bed conditions in the duct.