Characterization of mineral matter in coals and coal liquefaction residues. Annual report. [38 refs]

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Abstract
The aim of this investigation is to characterize the organic and mineral fractions of coals and coal liquefaction residues. Relationships are sought between the composition and properties of these components and the behavior of specific coals during liquefaction. Characterization is achieved by a wide range of techniques. These methods include: optical and scanning electron microscopy, x-ray diffraction, infrared spectroscopy, chemical analyses, magnetic measurements, and particle size analysis. From an investigation of the composition of coals and residues, it has been shown that most of the mineral components remain essentially unchanged during liquefaction. The major exceptions are the reduction of pyrite to pyrrhotite and the production of calcium salts from exchangeable calcium cations contained within low rank coals. Petrographic examination of the residues reveals the presence of unreacted macerals and insoluble carbonaceous components produced by the degradation of reactive macerals. The precise distribution of these components is a function of the feed coal and the process in which it was used (Solvent Refining or H-Coal). From an investigation into the composition of solids removed from liquefaction reaction vessels, it is shown that they are composed of two distinct components: one, a carbonaceous, coke-like material and the other, inorganic in nature. Themore » coke-like solids are produced by dehydrogenation and condensation reactions of organic precursors. In the case of liquefaction of low rank coals, inorganic solids are produced by the reaction of exchangeable calcium cations with carbon dioxide. For higher rank coals, these solids are predominantly composed of pyrrhotite, quartz, calcium salts, all intimately associated with carbonaceous phases. Knowledge of the formation of these reactor solids is important as their presence constitutes a definite processing problem for noncatalytic hydrogenative coal liquefaction.« less

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