An ammonia-based wet flue gas desulfurization (WFGD) simulation was built to simulate separately the two different aerosol formation mechanisms in ammonia-based desulfurization process of the inhomogeneous reaction mechanism and the entrainment mechanism. The electrical low pressure impactor (ELPI

Dekati Ltd.) was employed for the online measurement of aerosol concentration in the outlet flue gas after the WFGD scrubber. The pollutant PM sampler was used for aerosol sampling in the flue gas. The samples gathered were then scanned and analyzed by the field emission scanning electron microscope (FESEM). The results showed that the inhomogeneous reaction of NH3 escaped from desulfurization slurry with the moisture and SO2 in the flue gas was the dominating one of the two aerosol formation mechanisms in the ammonia-based WFGD

which produced the majority of the aerosols emitted from the scrubber. It was found that the aerosols were consisted mainly of submicron particles if counted in respect of numerical concentration and micron ones in respect of mass concentration. The amount of aerosols produced was depended mainly on the desulfurization solution pH along with the flue gas temperature at the inlet of WFGD

etc. The entrainment mechanism was of the secondary importance in the aerosol formation in the ammonia-based WFGD. The production of the aerosols was mainly related to the desulfurization solution concentration

the empty tower gas velocity

and so forth.