Effect of heating rate on structural changes of heat-treated coals

Abstract

For high-caking Goonyella and low-caking Witbank coals, dynamic viscoelasticity was measured at heating rates of 3-80°C/min. An increase in heating rate shifted the temperature which gives the maximum fusibility to higher temperature. Structural analyses (solvent extraction, ultimate analysis and FT-IR measurement) for the heat-treated coals showed that the temperature which the extraction yields, H/C atomic ratio and aromaticity greatly change also shifted to higher temperature by increasing heating rate, while (O + S)/C atomic ratio was not influenced by the heating rate so much. The enhanced fusibility by an increase in heating rate can be the result of decrease in possibility of cross-linking related to oxygen and sulfur functionalities.