Determination of Coal Rank by Thermogravimetric Analysis

INTRODUCTION The thermogravimetric analysis patterns of coals and their residues reveal subtle differences between coals and changes which occur during the processing. It is the purpose of this paper to call attention to some of the various processes occurring during the TG analysis, and to show how these patterns can be interpreted in terms of changes or differences in coal structure. It is also our purpose to show how manipulation of the various TGA parameters, i.e.,heating rate program, purge gas type, and the way in which the TG data are treated, can be used to reveal important aspects of the coal structure. Finally, the use of TGA as an objective criterion for determining coal rank is discussed.