Extraction and desulfurization of chemically degraded coal with supercritical fluids. Final report, July 1, 1983-December 1984

This report describes the progress made in the research entitled ''Extraction and Desulfurization of Chemically Degraded Coal with Supercritical Fluids.'' The desulfurization of coal, employing ethanol or methanol as solvent under supercritical conditions, has demonstrated its ability to selectively remove sulfur from the coal matrix. The objectives of the research are these: (1) to obtain rate data for supercritical extraction and desulfurization of coal, and to determine the desulfurization selectivity ratio for various coals; (2) to study the effect of chemical pretreatment of coal on desulfurization potential; and (3) to determine the characteristics of the desulfurized solid char and to measure and evaluate the liquid and gaseous streams. The experimental investigations have been carried out in two reactor systems, a semicontinuous reactor and a batch reactor. Experimental data obtained have indicated the following achievements: (1) the extraction and desulfurization of coal with supercritical ethanol is first order in nature, and the activation energies for coal extracted and sulfur removed are 30.3 and 21.0 Kcal, respectively; (2) the desulfurization selectivity ratio is found to be between 2.96 to 4.38 for four Illinois coal samples studied; (3) the effect of KOH pretreatment indicates an improvement of supercritical desulfurization potential; and (4) themore » evalution of product streams reveals that supercritical desulfurization generates a high Btu gas and coal-derived liquid in addition to the desulfurized solid product. 2 references, 5 tables, 9 figures.« less