Abstract:
Lignite coal containing 3.77wt%, db. of sulphur was pyrolysed in a thermogravimetric analyser under nitrogen and hydrogen stream at atmospheric pressure and temperature up to 900 ํC, with heating rates of 10, 20 and 40 ํC/min. Between 40 and 60% of total sulphur, which includes organic sulphur, was assessed for final temperature of 600-700 ํC. Rapid pyrolysis char was more efficient for desulphurization than slow heating pyrolysis char. The changes in the total and forms of sulphur that were determined by chemical analysis indicated that more sulphur was removed in pyrolysis was modeled by acombination of the volatile evolutions of three independent parallel lumps, which are attributed to the decomposition of moisture, light hydrocarbons and aromatic compounds, mainly. The decomposition of each lump was characterized by a single reaction, first order with respect to the amount of volatile yet to evolve. For nitrogen stream, the activation energies are 48.76, 144.71 and 238.05 KJ/mol, respectively and for hydrogen stream, the activation energies are 48.80, 157.73 and 237.25 KJ/mol, respectively.