LIQUEFACTION BEHAVIOR OF COALS - A STUDY BY FIELD-IONIZATION MASS-SPECTROMETRY AND PATTERN-RECOGNITION

Twenty Polish coals (72-88 wt% C, daf) were reacted with tetralin at 400°C and the conversions were determined. Field ionization (f.i.) mass spectra in the 100-700 m/z range were obtained by in-source volatilization from 50 to 500°C. Pattern recognition was applied to five replicates of the integrated, normalized f.i. mass spectra, conversion data, and proximate and ultimate analyses of the coals. A number of selected f.i. mass signals and conventional parameters showed high discriminatory power and hence can be used for classification of coals and prediction of conversion. In particular, the intensities of 45 f.i. mass signals were found to be significantly correlated with conversion for the coals investigated. The specific features of soft ionization mass spectrometry mean that almost exclusively molecular ions of low-temperature thermal degradation products are generated. It is therefore concluded that the correlate mass signals contain relevant information about reactive sites of the coal organic matter that are involved in liquefaction.