Scavenger materials for the chemical desulfurization of coal: Final report, 1 March--31 December 1987

Abstract

Chemical methods for the desulfurization of coal offer an advantage over physical (gravity) methods in that both pyritic and organically bound sulfur can be removed. Research was conducted on the ability of several scavenger materials to capture the sulfur that was liberated as coal was heated in a sealed reactor. The scavenger materials, selected on the basis of the stability of their sulfides, were Mn, CaO, Na/sub 2/O, and Zn. A sealed reactor approach was used to retain a large percentage of the volatile matter in the coal. In experiments where the coal and scavenger materials were physically separated, it was demonstrated that a coal containing 3.05% S initially could be desulfurized to a level of 1.4% S. Blending the coal with Na/sub 2/O yielded the best results. Sulfur levels of approximately 0.5% were achieved while more than half of the volatile matter in the coal was retained. Organic sulfur was more difficult to remove than pyritic sulfur, and it appeared that new organic sulfur bonds may have formed when pyrite decomposed. The effectiveness of zinc as a scavenger material was hampered by the formation of an adherent ZnS layer on Zn particles. 11 refs., 8 figs., 5 tabs.