Liberation of volatiles from Greek lignites during open system non-isothermal pyrolysis

Open system non-isothermal (programmed) pyrolysis with on line quantitative gas chromatographic analysis of pyrolysis gases (methane, carbon dioxide, carbon monoxide and molecular nitrogen) was performed on a series of Greek lignite samples. The investigation was aimed at exploring variations in the chemical properties of the samples and correlating them with petrographic data. For reference purposes one lignite sample from NW Germany was studied using the same procedure. The pyrograms of the four gases are sensitive indicators reflecting the chemical composition of the lignites. They represent unique fingerprints and document a greater variability in chemical composition than suggested from the petrographic data and proximate analysis.