In
this study, we investigated the emission characteristics of
condensable particulate matter (CPM) and sulfur trioxide (SO3) simultaneously through ammonia-based/limestone-based wet flue gas
desulfurization (WFGD) from four typical coal-fired power plants (CFPPs)
by conducting field measurements. Stack emissions of filterable particulate
matter (FPM) all meet the Chinese ultralow emission (ULE) standards,
whereas CPM concentrations are prominent (even exceed 10 mg/Nm3 from two CFPPs). We find that NH4
+ and
Cl– increase markedly through the ammonia-based
WFGD, and SO4
2– is generally the main
ionic component, both in CPM and FPM. Notably, the occurrence of elemental
Se in FPM and CPM is significantly affected by WFGD. Furthermore,
the established chemical profiles in FPM and CPM show a distinct discrepancy.
In CPM, the elemental S mainly exists as a sulfate, and the metallic
elements of Na, K, Mg, and Ca mainly exist as ionic species. Our results
may indicate that not all SO3 are included in CPM and they
co-exist in stack plume. With the substantial reduction of sulfur
dioxide (SO2), S distributed in SO3, CPM, and
FPM becomes non-negligible. Finally, the emission factors of CPM and
SO3 under typical ULE technical routes fall in the ranges
of 74.33–167.83 and 48.76–86.30 g/(t of coal) accordingly.