Separation of Functionalities in Pyrolytic Tar by Gel Permeation Chromatography-Gas Chromatography

Abstract

An analytical method combining gel permeation chromatography (GPC) and high resolution gas chromatography (GC) has been developed to analyze pine pyrolytic tars and their upgraded products. Pyrolytic tar, obtained from pine barks and wastes by the Tech-Air pyrolysis process, and its hydrogenation products have been separated by GPC into aromatics, phenols, light nonvolatiles and alkanes, and heavy nonvolatile fractions. The GPC using 10-nm μStyragel columns and THF as a solvent results in reasonably clean separations. The GC with the use of an internal standard gives percentage of volatiles. High resolution gas chromatography-mass spectrometry (GC-MS) has been used to characterize the separated fractions. Changes in composition during hydrogenation have been determined by comparing the GPC and GC analyses of the charge stocks and products. This technique provides fast analyses and allows the determination of compositional changes during the upgrading process.