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Halogen Emissions from Coal Combustion

AUTHOR: Lesley L. Sloss
DATE: February 1992

This report examines the pathways of the halogens in coal, peat and other feedstocks such as sorbents, through combustion and pollution control equipment, to eventual release to the environment. The extent to which the combustion conditions and pollution control equipment affect the release of these elements is discussed. The report also evaluates the contribution of coal to the total regional and global halogen emissions and concentrations and indicates the extent to which coal combustion may be responsible for any detrimental environmental effects.

The individual halogen contents of coal can vary by a factor of ten or more, proximity of the mine to the sea during coal formation being the greatest influence. Combustion conditions and pollution control equipment may appreciably reduce the eventual emissions of halogens to the atmosphere from coal combustion. Those processes designed to control emissions of SOx, such as limestone addition to the boiler and FGD, can be especially effective in reducing emissions of the acidic halogen gases.

The report concludes that halogen emissions from coal combustion are not generally of environmental concern. Indeed, with the continued implementation of FGD, emissions of halogens from coal combustion are not likely to be a problem in the future.