Studies in coal liquefaction with application to the SRC and related processes. Quarterly report, November 1981-January 1982

Abstract

The concentration of hydroaromatics in a coal liquefaction solvent is regarded as a significant factor in the determination of solvent quality. An analytical method is described based on catalytic solvent dehydrogenation (CSD) for the measurement of transferable hydrogen, including hydroaromatic sources, in a solvent. The dehydrogenation of several model compounds in the presence of Pd/CaCO/sub 3/ was conducted under batch conditions. Hydroaromatics containing six-member rings were found to dehydrogenate effectively. Lesser degrees of dehydrogenation were found for alkyl-substituted aromatics and saturated compounds. CSD was applied to a series of hydrogenated creosote oils plus several light recycle oils. The normalized H/sub 2/ volumes obtained by CSD could be correlated with the coal-dissolution ability of the creosote oils. It was not possible to include the light recycle oils in the same correlation. /sup 13/C-NMR was used to measure the transferable hydrogen of selected hydrogenated creosote oils and light recycle oils. Values of transferable hydrogen determined by /sup 13/C-NMR were generally larger than the corresponding values obtained by CSD. A smooth correlation was found between coal conversion and transferable hydrogen as measured by /sup 13/C-NMR. The light recycle oils could not be fitted to the curve defined by the creosote oils. Minerals indigenous to coal provide an internal but weak source of catalytic activity during liquefaction reactions. A sensitive probe reaction, cyclohexene hydrogenation/isomerization, was used to compare the catalytic activity of several clay minerals, oxides used as catalyst supports, pyrite and liquefaction residue ashes.