Preliminary geochemical analysis of coal-extracts and low-temperature tars of the Upper-Vistula Coal Region (Poland)
Three low coalified coal samples of Upper- Vistula Coal Basin (Poland) were object of geochemical analysis by pyrolitic, chromatographic and spectrographic methods. Coal extracts and low-temperature tars received in three temperatures: 390, 520 and 600°C in the presence of n-butanol-l vapour were separated into three fractions: aliphatic, aromatic and polar (NSO compounds + asphaltenes) using preparative TLC for gross composition assessment. Infrared spectroscopy of overall primary tars indicates that lower coalified coals give primary tars containing much higher amounts of oxygen 'compounds then higher coalified coals and that with increase of pyrolysis temperature the content of aliphatic structures in tars tends to decrease. Aliphatic compound fractions were analysed by gas chromatography to assess changes in n-alkanes, n-alkenes and isoprenoid compounds distribution and changes of main biomarker parameters with changes of pyrolysis temperature comparing to coal extracts. Results of gc analysis indicated similar thermal maturity of coals and their various depositional environment ( oxic in the case of the Czeczott and J anina coals and anoxic-suboxic for the Siersza coal). In lower temperatures of pyrolysis (390°C) high predominance of even-carbon-number n-alkanes and n-alk-l-enes was found caused by generation even-carbon-number aliphatic compounds from coal macromolecule. As a probable source of pristane in coals vitrinite macerals were supposed.
Bibliogr. 26 poz.