[Characteristics of Condensable Particulate Matter in Ultra-low Emission Coal-Fired Power Plants]

The condensable particle matter (CPM) from coal-fired power plants has attracted significant attention for its potential influence on air quality. The knowledge of CPM emissions from coal-fired power plants is limited. In this study, CPM was collected at the inlet and outlet of wet flue gas desulfurization (WFGD) and the outlet of wet electrostatic precipitator (WESP) using in-direct dilution method. Both mass concentration and water-soluble ions of CPM were analyzed after sampling. The gas precursors were measured at the same time. We showed that gas precursors such as HCl, HNO₃, SO₃, and NH₃ significantly contributed to CPM from coal-fired power plants. As the temperature of flue gas decreased, these gas precursors were observed to form CPM. The major components of CPM were water-soluble ions such as SO₄^2-, Cl^-, NO₃^-, and NH₄⁺. WFGD and WESP could reduce the CPM gas precursors. Therefore, CPM concentrations after WFGD and WESP of the five tested coal-fired power plants were reduced by 27% and 45%, respectively. In addition, the condensation of SO₃ increased SO₄^2- concentration but reduced Cl^- and NO₃^- contents. Finally, SO₄^2- was found to be the major water-soluble ion of CPM.