In order to study the influence of bed temperature and selective noncatalytic reduction(SNCR) denitration on NO and N_2O emission from CFB boilers burning anthracite

an experimental study was carried out on a 1 MW CFB test equipment. The results show that

when the bed temperature was increased from 880 ℃ to 970 ℃

the NO emission mass concentration increased from 119.5 mg/m~3 to 226.0 mg/m~3

and the N_2O emission mass concentration decreased from 216.0 mg/m~3 to 102.2 mg/m~3. The denitrification efficiency increased from 0 to 50.72% when the ammonia to nitrogen molar ratio NSR was 0～3.7. When the NSR was further increased to 5.2

the denitrification efficiency rose to 53.61%

with a slow increase. With the increase of NSR from 0 to 1.7

the N_2O emission mass concentration increased from 84.3 mg/m~3 to 118.3 mg/m~3

with a slow growth rate. Further increasing the NSR to 2.0

the emission mass concentration of N_2O increased to 187.7 mg/m~3

of which the growth rate increased. Contineously increasing the NSR to 5.2

the emission mass concentration of N_2O increased to 381.4 mg/m~3. When the SNCR process with urea as reducing agent is adopted in CFB boiler

to enhance the denitrification efficiency

only increasing the NSR not only has limited effect

but also will significantly increase the N_2O emission by excessive injection of reducing agent.