STUDY ON THE INFLUENCE MECHANISM OF DEHYDRATION AND DEVOLATILIZATION ON VARIOUS FORMS OF SULFUR IN COAL WITH DIFFERENT METAMORPHIC DEGREES

Dehydration and devolatilization on the behavior and phase transformations of various sulfur forms in coal with different metamorphic grade. The nature of sulfur in coal includes and pyritic, sulfate, organic, and elemental sulphur, and the fate of these forms during thermal processes determines the merits of desulfurisation. It was determined through thermal experiments conducted on coals of different metamorphic classes (lignite, bituminous, anthracite) that the dehydration process has a modest but measurable impact on sulfur oxidation with major changes recorded in the high-density coals. A general observation, however, was that devolatilization had a significant effect in the low rank coals such as lignite where higher volatility resulted to higher sulfur release at the pyrolysis stage. In this regard, the study demonstrates that organic sulfur transformations are most important in low- and high-density regions of low-rank coals and that sulfite sulfur has the least amount of response to dehydration. Sulfate sulfur however showed a significant decrease after dehydration particularly in high density part of anthracite. These results propose new knowledge on sulfur change reactions for coals, which can guide advanced desulfurization suggestions to the coal industry[1].