Conversion of Fuel-N to N2O and NOx during Coal Combustion in Combustors of Different Scale

Abstract With focus on investigating the effect of combustor scale on the conversion of fuel-N to NO x and N 2 O, experiments are carried out in three combustors, including single coal particle combustion test rig, laboratory scale circulating fluidized-bed boiler (CFB) and full scale CFB in this work. For single coal particle combustion, the majority of fuel-N (65%–82%) is released as NO x , while only a little (less than 8%) fuel-N yields N 2 O. But in laboratory scale CFB, the conversion of fuel-N to N 2 O is increases, but the conversion of fuel-N to NO x is quite less than that of single coal particle combustion. This is because much char in CFB can promote the NO x reduction by increasing N 2 O formation. In full scale CFB, both of the conversion of fuel-N to NO x and the conversion of fuel-N to N 2 O are smaller than laboratory scale CFB.