FLASH PYROLYSIS OF COALS - TEMPERATURE-DEPENDENT PRODUCT DISTRIBUTION

As a part of an on-going study of the thermally induced conversions of sub-bituminous to bituminous coals, a Columbian coal has been studied using a hyphenated pyrolysis-gas chromatography/mass spectrometry sys tem. The studies include direct flash pyrolysis of the coals at 750 de grees C as well as a step-wise pyrolysis, e.g. thermovaporization (400 degrees C), followed by pyrolysis at 750 degrees C and/or 1025 degree s C, The pyrolysis of coals leads to the formation of volatile as well as non-volatile products, the latter being partly volatilized in a po ssible subsequent pyrolysis process. The present study focusses on the volatile products formed during the single stages of the thermal conv ersion of the coals and the possible rationalization in terms of an ex tended kinetic model.