The characterisation of coals and their respective chars formed at 1300°C in a drop tube furnace

Thirty-two coals from around the world were sieved into two size fractions (53-75 and 106-125 mu m) and characterised using proximate analysis and standard petrographic techniques as well as the Nottingham reactive assessment program. A small amount of each sample was pyrolysed using a drop tube furnace operating at 1300 degrees C, 100 ms and 156 (v/v) oxygen. The chars were mounted in resin, polished and characterised morphologically using manual and automated image analysis techniques. The intrinsic reactivity of each char was evaluated using a themogravimetric analyser under non-isothermal conditions. Both intrinsic reactivity and char morphology were found to relate to the coals original petrographic characteristics, although not directly to either maceral content or vitrinite reflectance measurements. (C) 1999 Elsevier Science Ltd. All rights reserved.