Particle-Size Distributions and Heavy Metal Partitioning in Emission Gas from Different Coal-Fired Power Plants

This study investigated the emission characteristics of particulate matter (PM) and several heavy metals from different Korean coal-fired utility boilers. Emission measurements examined PM and gas emission concentrations, particle size distributions (PSDs), the partitioning of heavy metals, and the concentration of ultrafine particles. The facilities examined included two bituminous coal-fired power plants (pulverized coal combustors) and one anthracite coal-fired power plant (circulating fluidized bed combustor). Measurements were made at locations before the systems' air pollution control devices (APCDs). The PSDs prior to PM control were bimodal from all facilities. The mass ratios of the fine particle modes to larger particle modes were dependent on the ash content of the fuel and the boiler type. Additionally, the overall PM concentration before the APCDs correlates well with the ash content of the coals. Thermodynamic equilibrium predictions indicate that the metal speciation (and volatility) depends not only on the halogen content of the fuel, but also on the localized stoichiometric ratio of combustion.