Comparative study on the characteristics of condensable particulate matter emitted from three kinds of coal.

Condensable particulate matter (CPM) is quickly formed by several gaseous substances in flue gas after emission and belongs to primary particulate matter emitted into the atmosphere by stationary sources. Many studies have shown that current CPM emissions from coal-fired stationary sources far exceed filterable particulate matter, and the issue of CPM emissions has attracted widespread attention. The current research on CPM mainly focuses on its emission characteristics in stationary sources and its migration characteristics in pollutant-controlled equipment, lacking the characteristics of CPM directly generated by fuel combustion. In this study, a one-dimensional flame furnace is used as a stable source of flue gas in the laboratory. The concentration (including inorganic and organic components) and chemical composition (including water-soluble ions, metal elements, and organic matters) of CPM are obtained by the combustion of three kinds of coal (Inner Mongolia lignite, Jinjie bitumite, and Ningxia anthracite) that China consumes in large amounts. The characteristics of CPM including emission factors obtained from different kinds of coal under various experimental conditions are comparatively analyzed. Moreover, a scanning electron microscope-energy-dispersive spectrometer is used to observe the morphology and elemental composition of CPM collected on the filter membrane after the combustion of different kinds of coal. Results show that CPM is mainly in the form of droplets or spheres, and heavy metal elements such as Hg, As, Se, and Sb are detected. These valuable data will enrich people's understanding of the characteristics of CPM generated by coal combustion and can provide data references for evaluating the influence of CPM on the environment.