Researches on N_2O emission characteristics in limestone desulfurization process in the past few years mainly focused on mechanism and laboratory research

while the data measured in the field was rare.In order to explore the influence of limestone desulfurization on N_2O emission mass concentration in circulating fluidized bed(CFB) fieldtest

the variation trend of SO_2

N_2O and NOx in flue gas of boiler at different loads was comprehensively measured and analyzed after limestone was put into the 150 MW CFB unit for desulfurization.The results show that

the SO_2 emission mass concentration reduced from 1 200 mg/m~3 to below 100 mg/m~3 in a short time.When the limestone was fed at a certain rate

the N_2O emission mass concentration decreased to some extent

which was related to the catalytic effect of CaO on the thermal decomposition of N_2O.However

the NOx emission mass concentration increased significantly.With the increase of boiler load

the N_2O emission mass concentration decreased as a whole.Within the combustion temperature range of CFB boilers

N_2O is likely to replace NOx as the main source of pollutants.