Content and Distribution of Trace Elements and Polycyclic Aromatic Hydrocarbons in Fly Ash from a Coal-Fired CHP Plant

The levels of trace elements and polycyclic aromatic hydrocarbons (PAHs) in fly ash generated by coal combustion have received considerable attention in recent years, due to their potential environmental impact. Sixteen high priority PAHs and 14 trace elements in coal fly ash were measured. The particle sizes of fly ash showed a bimodal distribution, and most ash particles were within a range of 20–25 µm in diameter. The fly ash exhibited high contents of CaO and SO3, which was influenced by the desulfidation treatment of limestone. The Be, Cu, Ni, V, Se, Mo and Cd contents increased significantly with decreasing particle sizes of fly ash, while those of Zn and Pb showed no obvious trends. PAHs with three- and four-rings were the dominate species in all the fly ash. The amount low molecular weight PAHs with two-, three- and four- rings was inversely correlated with the particle sizes of the fly ash.