Microscopic characterization of coal residues from supercritical desulfurization of Illinois coal

• Published in: Fuel processing technology Vol. 17; no. 1; pp. 85 - 102
• Main Authors: Hippo, E.J., Murdie, N., Chen, J.W., Muchmore, C.B., Kent, A.C.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.08.1987; Elsevier Science
• Subjects: Applied sciences; Coal and derived products; Energy; Exact sciences and technology; Fuels; Mechanical preparation; Processing; Desulfurization; Alcohol; Optical microscopy; Coal preparation; Supercritical state; Operating conditions
• ISSN: 0378-3820; 1873-7188
• DOI: 10.1016/0378-3820(87)90019-1

An investigation of the microscopic properties of residues produced from Illinois coal treated under various supercritical alcohol extraction conditions has been conducted. The objective of this investigation was to obtain a better understanding of the supercritical alcohol/coal desulfurization system. It was found that pyrite is converted progressively to pyrrhotite and then to troilite. Also, coal particles tended to become fluid and form coke. The degree of coke formation and size of anisotropic units (optical texture) were found to correspond to the extent of desulfurization. These correlations were found to be solvent dependent. Zoning effects were also observed in both the organic and inorganic phases. These effects appear to be mass or heat transfer limited and related to the operation of the batch reactors employed in obtaining samples for this study. The investigation is continuing, employing smaller reactors with improved heat and mass transport properties. Attempts will be made to determine if desulfurization is enhancing fluidity or if fluidity is enhancing desulfurization.