Formation and destruction of N2O in pulverized fuel combustion environments between 750 and 970 °C

Abstract Formation and destruction of N 2 O were investigated under dilute pulverized coal combustion conditions in an entrained-flow reactor. The effects of temperature, atmosphere (oxidizing and reducing) and reaction environment (homogeneous and heterogeneous) were studied. N 2 O was measured on-line by FT-i.r. spectrometry. No N 2 O evolution occurred above 950 °C. At oxygen concentrations below 1.5%, in the presence of CO, the N 2 O already formed was rapidly destroyed above 900 °C and fairly rapidly even at 830 °C. At high oxygen concentrations, destruction occurred more slowly, and not at all below 900 °C. Heterogeneous reactions did not noticeably increase the destruction rate of N 2 O in a dilute fuel-air suspension. Low O N ratio of coal favoured N 2 O formation. The results should assist the design of low-temperature combustors that generate only low levels of N 2 O.