COAL CHAR COMBUSTION - INTERPRETED IN LIGHT OF FUNDAMENTALS OF GAS-CARBON REACTIONS.

Once coal liquefaction and coal gasification processes become commercial realities, there will be large amounts of by-product residual chars available. Many possible uses have been considered for these chars, including their combustion in power plants. Coal chars exhibit a broad range of intrinsic reactivities to O//2, depending upon the rank of the starting coal and process conditions used in the particular synfuels process where they are produced. In this paper, the fundamentals of gas-carbon reactions in different reaction zones will first be reviewed. Intrinsic reactivities of a large number of chars produced from a broad spectrum of coals of varying rank under carefully controlled laboratory conditions will next be considered. These considerations will then be used to interpret the low and high temperature combustion behavior of chars obtained as residues from selected coal conversion processes.