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Power from Coal--Where to Remove Impurities?

AUTHOR: Gordon R. Couch
DATE: August 1995

The study considers both the constraints and the opportunities which apply to the removal of impurities from coal, at all stages of the coal-to-electricity chain. The commercial and regulatory background, which varies considerably from country to country is discussed. Much depends on whether there is competition in the local market when purchasers will probably switch supplies before considering additional coal cleaning. There is a lack of understanding and of market mechanisms to facilitate the optimisation of the coal-to-electricity chain, in particular the tendency to assess the mining operation on a tonnage basis but other stages on a coal quality basis. Coal cleaning at either the mining site (where it traditionally takes place) or at the power plant are discussed.

The removal of impurities during and immediately after combustion or gasification are discussed. Total amounts of SO2 emissions and of residues from the use of coal for heating and steam-raising are estimated in each of the worlds major coal producers and users.

There is lack of reliable and published data for making overall recommendations based on costs. It is also difficult to generalise, since coals vary widely in their properties. However, advanced cleaning technologies are likely to play only a limited role in optimising the removal of impurities from coal when used for power generation. The possibility of separations carried out at the power plant requires further investigation.