Distribution Law and Transfer Mechnism of Mercury during Combustion of Pulverized Coals

Emission and control of mercury from coal combustion is an emerging and frontier area and going to attract more attention in future. During combustion of pulverized coals, most of the Hg volatilizes. Variable amounts of Hg are captured by fly ash and essentially none accumulates in the bottom ash. Hg is emitted to the atmosphere as gaseous (dominate) and solid-phase (subordinate) pollutants. In this paper, a summary of the status of research related to mercury speciation and progress in the development of promising control technologies for coal-fired power plants are provided. Fly ashes have been sampled from the electrostatic precipitator (ESP) of three power plants. The concentration of mercury in these samples and the particle size distribution of the fly ash were determined. Results indicate that the mercury concentration in fly ash is increase with the particle size fining. And mercury partitioning in emission streams, enrichment in submicron particles vaporization and emission in flue gas, and the mobility and leaching behavior of mercury in coal and combustion waste are summarized.