Simultaneous thermogravimetric - mass spectrometric study on the pyrolysisbehaviour of different rank coals

Simultaneous thermogravimetry-mass spectrometry was used to study the pyrol ysis behaviour of an anthracite and three bituminous coals of different vol atile matter content. This system was optimised by using calcium oxalate as a reference for calibration. A normalisation method that permitted a semiq uantitative comparison between the volatile species of the coals was also d eveloped. The instantaneous evolution of the volatile compounds was studied by means of temperature-programmed pyrolysis experiments. The peaks varied in shape, temperature and size, and showed a marked dependence on coal ran k. This can be attributed to the varying amounts of the different functiona l groups in the coals studied. Special attention was paid to the nitric oxi de released during pyrolysis, together with its precursor species. (C) 1999 Elsevier Science B.V. All rights reserved.