NEW APPROACH TO THE CHARACTERIZATION OF PYROLYSIS COAL PRODUCTS BY GAS-CHROMATOGRAPHY MASS-SPECTROMETRY

A method for the characterization of coal thermal behaviour, based on gas chromatographic-mass spectrometric analysis of the pyrolysate, is presented. Twelve different coal samples, representative of the entire coal rank, were selected for this study. The pyrolysis products, obta ined at 800 degrees C, were first collected and then analysed in two G C-MS systems. The sampling apparatus consisted of three different trap s in order to separate the products into three fractions on the basis of their volatility. The GC-MS analysis was also arranged according to this criterion. A packed column, coupled to a double-focusing magneti c mass spectrometer, was used for the volatile fractions of the pyroly sate and a capillary column, coupled to a quadrupole analyser, was emp loyed for the analysis of the condensed fraction. Sampling and analysi s procedures were carried out separately, thus allowing careful optimi zation of the strategy for the characterization of the pyrolysate. The condensate was analysed in the selected-ion monitoring mode for the d etermination of different classes of compounds. Some evaluations and c omparisons, extrapolated from the results obtained, are presented.