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 system. The studies include direct flash pyrolysis of the coals at 750 °C as well as a step-wise pyrolysis, e.g. thermovaporization (400 °C), followed by pyrolysis at 750 °C and/or 1025 °C. The pyrolysis of coals leads to the formation of volatile as well as non-volatile products, the latter being partly volatilized in a possible subsequent pyrolysis process. The present study focusses on the volatile products formed during the single stages of the thermal conversion of the coals and the possible rationalization in terms of an extended kinetic model.