Control of mercury emissions from coal-fired electric utility boilers.
نویسندگان
چکیده
Introduction During combustion, the mercury (Hg) in coal is volatilized and converted to elemental mercury (Hg) vapor in the high temperature regions of coal-fired boilers. As the flue gas is cooled, a series of complex reactions begin to convert Hg to ionic mercury (Hg) compounds and/or Hg compounds (Hgp) that are in a solid-phase at flue gas cleaning temperatures or Hg that is adsorbed onto the surface of other particles. The presence of chlorine gas-phase equilibrium favors the formation of mercuric chloride (HgCl2) at flue gas cleaning temperatures. However, Hg oxidation reactions are kinetically limited and, as a result, Hg enters the flue gas cleaning device(s) as a mixture of Hg, Hg , and Hgp. This partitioning of Hg into Hg, Hg , and Hgp is known as mercury speciation, which can have considerable influence on selection of mercury control approaches. In general, the majority of gaseous mercury in bituminous coal-fired boilers is Hg. On the other hand, the majority of gaseous mercury in subbituminousand lignite-fired boilers is Hg.
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ورودعنوان ژورنال:
- Environmental science & technology
دوره 40 5 شماره
صفحات -
تاریخ انتشار 2006