Influence of additives of various origins on thermoplastic properties of coal

Two coking coals of different rank were chosen in order to assess the influence of various additives on their thermoplastic properties. Six additives of different origin and characteristics were selected: two non-coking coals, together with a commercial coal tar pitch, a residue from the bottom of the benzol distillation tower and two residues from the tyre recycling industry. The effect of the additives on coal thermoplastic properties was assessed by means of the Gieseler test. The additives were pyrolyzed to a final temperature of 550 °C and the tar characterized by means of Fourier transform infrared spectroscopy (FTIR) and gas chromatography (GC). The influence of the additives on coal thermoplasticity is related to the volatile matter content of the additive, its evolution profile with temperature and the composition of the tar obtained during the pyrolysis of the additives.