In order to study the migration characteristics of SO_3 and condensable particulate matters (CPM) from ultra-low emission coal-fired power plants

the mass concentrations of SO_3 and CPM in the flue gas from different power plants were detected.The results indicate that

the SCR denitration system contributes 42.01%～52.08%of the total SO_3 formation mass concentrations

the removal rate of SO_3 by the wet flue gas desulfurization (WFGD)system is 51.20%～65.20%

and the removal rate of SO_3 by the wet electrostatic precipitator (WESP) is77.25%～79.27%.The ultra-low emission coal-fired power plants equipped with WESP can effectively remove the SO_3 in the flue gas and the removal efficiency can reach 94.28%.Besides

the existing pollutant control devices have some effect on CPM removal.The removal rate of CPM by the WFGD is 34.64%～47.20%%

and the removal rate of CPM by the WESP is 36.20%～39.26%.The CPM is mainly composed of inorganic components

and the inorganic components are mainly composed of acid ions such as SO_4~(2–)

Cl~–and NO_3~–.The NH_4~+and SO_4~(2–)in the CPM come from NH_3 and SO_3 in the flue gas

and their mass concentrations are positively correlated with the mass concentrations of NH_3 and SO_3 in the flue gas.