Characteristics of particulate matter emitted from a coal-fired power plant

Abstract

Particulate matter (PM) emitted into the atmosphere from a hard coal-fired power plant equipped with a pulverised fuel boiler was studied using X-ray diffractometry (XRD), inductively coupled plasma mass spectrometry (ICP-MS), and scanning electron microscopy fitted with X-ray energy-dispersive spectrometry (SEM-EDS). The PM emitted from coal-fired power plants is rarely studied, in contrast to fly ash collected during flue gas cleaning. The material of PM is composed of particles differing in size, morphology, and chemical composition. Aluminosilicate spherical particles dominate, but other particles also occur (irregular aluminosilicate particles, char particles, irregular particles of quartz, Fe oxides, particles rich in Fe, Cr and Ni, barite, and others). The size of other particles varies from 50 µm to 250 µm. The emitted PM is strongly enriched in several elements in comparison to average coal ash or upper continental crust (e.g., Ag, Bi, Cd, Cr, Hg, Mo, Ni, Re, Se, and Zn). The content of bioavailable, water-soluble fraction (containing S, Ca, K, Na, Cl and subordinate Zn and Ni) is ca 5%. The broad variation of the size and composition of the emitted PM indicates the potential environmental impact and possibility of dispersion over a large area.