Effects of preheating temperature, O2 distribution concentration and combustion temperature on the formation of PM during preheating-low NO combustion

Abstract

Clarifying the mechanism of multi-mode PM formation during pulverized coal preheating-combustion is expected to facilitate the synergistic control of NO and PM, and a significant low carbon way to achieve clean combustion. In this study, combustion experiments under different preheating-combustion conditions were conducted in a preheating-combustion furnace. Based on this, a system coupling design was explored by combining preheating-combustion with air staging. The results demonstrated a significant simultaneous reduction in both PM and NO during preheating-combustion, achieving a synergistic control of PM and NO emissions. With an increase in preheating temperature(Tp), the NO formation decreased, while the PM10 formation increased. Increasing the excess air coefficient(αp) reduced the PM10 formation, while the NO exhibited a trend of initially decreasing and then increasing. The impact of the combustion temperature(Tc) on NO and PM was more pronounced, especially with a significant increase of 80.59% in the PM0.3 (from 1300 K to 1700 K). Furthermore, the effect of the interaction of the three factors on NO: αp and Tc > αp and Tp > Tp and Tc. After coupling preheating-combustion with air staging, the formation of NO and PM0.3 decreased by 33.27% and 17.43%, respectively, compared to the preheating-combustion baseline.