PY-GC/AED STUDIES ON THE THERMOCHEMICAL BEHAVIOR OF SOFTWOOD

The thermochemical behavior of sawdust from Scots pine (Pinus sylvestris) was investigated by pyrolysis-gas chromatography with atomic emission detection (Py-GC/AED). At temperatures of 400, 600, 800, and 1000 degrees C the conversion yields of the product fractions of volatile products (''light'' and ''heavy'' fractions), condensable tars and char residue were determined. The use of the lower pyrolysis temperatures (400 and 600 degrees C) yielded fewer volatiles (40-60% of the initial wood) than did the higher pyrolysis temperatures: the corresponding yield at 800 and 1000 degrees C was about 75% of the initial wood. The conversion yield of condensable tars remained relatively constant (25-35% of the initial wood) within the temperature range studied, whereas an increase in temperature reduced drastically the amount of char residue. The elemental analysis data for the two subfractions of volatile products indicated clear differences in the chemical compositions of these fractions. The content of the prominent gaseous components, carbon monoxide and carbon dioxide, in the ''light'' fraction of volatile products was measured by GC.