Emission characteristics of PM2.5 and components of condensable particulate matter from coal-fired industrial plants

Abstract

Particulate matter (PM), including condensable particulate matter (CPM) and filterable particulate matter (FPM), emitted from coal combustion is one of the major contributors to air pollution. In this study, CPM and FPM were sampled from two coal-fired industrial boilers with air pollution control devices (APCDs). The emission concentration of total PM (CPM and FPM) and inorganic components of CPM were studied. The organic fractions in CPM and raw coal were analyzed using a gas chromatograph/mass spectrometer (GC/MS). The concentrations of total PM in the flue gas decreased from 1475.61 to 7.68 mg/Nm3 in unit 1, and from 2451.62 to 29.38 mg/Nm3 in unit 2 after the flue gas passed through the APCDs. CPM accounted for 51.42–91.93% of total PM emitted from stacks, of which organic components (73.87–96.30%) were one of the main constituents. Although aromatic hydrocarbons are one of the major components of raw coal, they were almost nonexistent in the CPM emitted from coal combustion. Saturated hydrocarbons accounted for the largest proportion of organic components in CPM, 49.19% in unit 1 and 61.16% in unit 2. The proportion of esters in the oxygen-containing derivatives of CPM emitted from two units was relatively high. SO42− was the inorganic component with the largest concentration in CPM emitted from the boiler units. This study will improve the understanding of the emissions levels of PM2.5 and the properties of CPM that originate from the coal-fired industrial processes.