Size exclusion chromatography of pyrolysis and hydropyrolysis tars from Spanish low rank coal

Abstract

The molecular weight distributions of tars obtained from a Spanish lignite by pyrolysis and hydropyrolysis at 500–700 °C have been determined by size exclusion chromatography (SEC) using tar fractions as calibration standards. Two peaks, at 400–500 amu and 250–280 amu were observed in the chromatograms of all the tars studied, but their relative intensities varied with the pyrolysis temperature and atmosphere. The variations appear to be related to thermal cracking at higher temperatures.