The mass concentration of SO_3 in coal-fired flue gas is relatively low

and the SO_3 is active to be adsorped

but the SO_3 capture efficiency is low

so it is difficult to obtain typical SO_3 acid fog emission data in coal-fired power plants. Based on analysis of the mainstream SO_3 acid mist monitoring methods

the isopropanol absorption method was used to carry out experimental research on synergistic removal of SO_3 from typical coal-fired power plant flue gas treatment equipment. The results show that

the mass concentration of SO_3 produced by coal combustion varied greatly with different combustion modes

and it was positively correlated with the sulfur content in coal. In SCR flue gas denitration process

the SO_2/SO_3 conversion rate ranged from 0.44% to 1.02%.The removal efficiency of SO_3 by electrostatic precipitator was generally about 40%. When the mass concentration of SO_3 at inlet of the precipitator was high

its removal efficiency can be slightly improved

and the combined electrostatic bag precipitator had better cooperative removal efficiency for SO_3. Under different working conditions

the removal efficiency of SO_3 by wet electrostatic precipitator was 44%～75%

and its emission mass concentration was generally controlled below 5 mg/m~3. The removal efficiency of SO_3 in conventional wet desulfurization ranged from 38% to 56%

and the tray tower had better synergistic removal effect for SO_3 acid mist.