Chemical characteristics of filterable and condensable PM2.5 emissions from industrial boilers with five different fuels

This study investigated the chemical characteristics of fine particulate matter (PM2.5) emitted from industrial boilers, each utilizing one of five fuels, including solid (coal, wood), liquid (heavy oil, diesel) and gas (natural gas) phase. The investigated boilers are abbreviated as CFBs, WFBs, HOFBs, DFBs and NGFBs respectively. A field sampling campaign was conducted to collect both filterable particulate matter (FPM) and condensable particulate matter (CPM) samples using USEPA Method 201A and Method 202 respectively. Mass concentrations and chemical compositions (including carbon contents, water-soluble ions and metal elements) of the collected PM2.5 samples were analyzed. PM2.5 (FPM + CPM) emission concentrations for CFBs, WFBs, HOFBs, DFBs and NGFBs were found to be 46.6 ± 6.43, 122 ± 54.7, 191 ± 68.5, 7.94 and 7.37 ± 3.29 mg/Nm3 respectively. Results suggest that OC was dominant in the flue gas of solid fuel (CFBs and WFBs) combustion, and high EC emitted from liquid fuel (HOFBs and DFBs) combustion for FPM. Inorganic fraction accounted for more than 50% of total CPM for solid- (CFBs and WFBs) and gas-fuel (NGFBs) boilers, whereas organic fraction was mainly composed in total CPM for liquid-fuel (HOFBs and DFBs) boilers. The contents of water-soluble ions (SO42−, NO3−, NH4+ and Cl−) were significantly enriched in PM2.5. Na, Ca and K were predominant in CPM for all types of boilers.