In a bench scale precalciner

the characteristics of NO release from coal char combustion were investigated in various conditions (different temperatures and presence of cement raw meal). The mechanism of NO formation was also discussed.The results indicated that the characteristics of NO emission from three kinds of chars were obviously different because of coal physical structure and chemical properties. The rate of NO formation increased with increasing temperature

however

sometimes the phenomenon was irregular. The rate and amount of NO formation clearly rose in the presence of cement raw meal

which suggested that cement raw meal showed distinct catalytic effect on NO formation.NO originated mainly from the oxidation of fuel nitrogen in the industrial precalciner. The conversion of char-N to NO was controlled by two competitive reactions: oxidation of fuel nitrogen and reduction of NO.