Formation and migration of soluble ions in condensable particulate matter in limestone-gypsum wet flue gas desulfurization system

Abstract

In this work, the emission characteristics of condensable particulate matter (CPM) and soluble ions in the inorganic components after wet flue gas desulfurization (WFGD) were investigated by adjusting the operating parameters of the limestone-gypsum WFGD system. Using a combination of US Method 202 and US EPA Method 5 as the primary measurement method, the study is an experimental study and analysis of the properties of CPM emitted from a limestone-gypsum WFGD system. Based on the measurement results, the influence of some important WFGD operating parameters on CPM emissions was evaluated. The results showed that CPM accounts for 84% of total particulate matter (TPM) emissions in desulfurized flue gas. The composition of CPM is primarily inorganic, comprising 96% of the components, with only a small portion being organic at 4%. The CPM that condensed to a solid state was generally less than 1 μm in diameter and mostly came from WFGD process. The analysis of soluble ions showed that Ca2+ and SO42- were the main ionic components in CPM. By adjusting the desulfurization operating parameters (inlet flue gas temperature, desulfurization solution temperature, desulfurization solution concentration), the concentration of soluble ions can be reduced to different degrees, so as to achieve the purpose of reducing CPM emission. This demonstrated that the CPM emission problem of limestone-gypsum WFGD system could be relieved by operating parameter optimization.