Coal Desulfurization Via Chemical Leaching with Aqueous Solutions of Sodium Sulfide and Polysulfide

摘要

The objective of this work has been the development of a novel process for coal desulfurization which would surmount the difficulties and generally undesirable characteristics of already proposed or existing processes. Toward this end, a process was conceived whereby sulfur constituents would be leached from slurried coal by aqueous solutions of sodium monosulfide and polysulfide. Use of these solutions was suggested by published findings which indicated that they would be effective in removing both inorganic and organic sulfur from coal upon treatment of the latter at room temperature and pressure. In sharp contrast to claims made in the literature, our experimental results demonstrated that sodium disulfide solutions are not effective in desulfurizing coal. Conclusions of a more positive nature have also been drawn. First, the regeneration scheme developed herein, being far superior to existing proposals for such regeneration, should be applied to those systems where polysulfides may, in fact, be effectively used for desulfurization (i.e., of oil). Secondly, data gathered suggest that the use of aqueous sodium disulfide should be further investigated as the basis for an analytical tool by which the elemental sulfur content of coals may be determined. (ERA citation 04:054022)