Objective The effects of different operating parameters and flue gas conditions on the separation efficiency of sulfur trioxide in flue gas by controlled condensation method (CCM) were studied to avoid the corrosion perforation of the device and the generation of high-salt sewage due to the high mass concentration of sulfur trioxide in flue gas.

Methods The effects of different operating parameters and flue gas conditions on the condensation separation efficiency of sulfur trioxide in flue gas were studied by using the self-developed sulfur trioxide in flue gas control condensation efficiency evaluation device.

Results The change of flue gas flow rate and sulfur trioxide mass concentration in flue gas had a significant effect on the condensation separation efficiency of sulfur trioxide. The introduction of quartz filter cotton at the end of the condensation system could obviously eliminate the influence of sulfur trioxide mass concentration change in flue gas on the condensation separation efficiency of sulfur trioxide. When the temperature of the flue gas sampling pipeline was higher than the dew point of the acid mist and the temperature of the condensation pipe was between the dew point of the acid mist and the dew point of the water vapor, the holding temperature of the flue gas sampling pipeline and the temperature change of the condensation pipe had little effect on the condensation separation efficiency of sulfur trioxide in the flue gas. The change of sulfur dioxide mass concentration in flue gas has little effect on the condensation separation efficiency of sulfur trioxide in flue gas.

Conclusion According to the established sulfur trioxide condensation separation method, the separation efficiency for sulfur trioxide is greater than 95%.