Isothermal pyrolysis studies have been conducted on a Green River Formation oil shale from Colorado and a New Albany oil shale from Kentucky. The conversion of kerogen to bitumen, oil, gas, and residue products was obtained for different reaction times in the temperature range 375-425 O C . In addition, elemental analyses, NMR carbon aromaticities, and molecular weights were obtained for the produced oil and bitumen. The maximum amount of extractable bitumen in the New Albany shale was 10% or less of the original kerogen at any given temperature, indicating that direct conversion of kerogen to oil, gas, and residue products is a major pathway of conversion of this shale during pyrolysis. In contrast, a significant fraction of the Colorado oil shale kerogen was converted to the intermediate bitumen during pyrolysis. The bitumen data imply that the formation of soluble intermediates may depend on the original kerogen structure and may be necessary for producing high yields by pyrolysis. When the pyrolysis reaction was quenched after 20 min at 425 "C, 95% of the kerogen in Colorado oil shale was converted to soluble products in the form of oil and bitumen. In general, the hydrogen-to-carbon ratios, carbon aromaticities, and molecular weights of the oils from each shale were fairly constant at all times and temperatures, whereas for the bitumen these properties varied with time and temperature. However, there were differences in the oil properties between the two shales that reflect the differences in the original kerogen structures.

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Different methods of drying coal were investigated to determine if drying can be accomplished without altering the coal structure and reactivity toward liquefaction. Coal-drying methods included thermal and microwave drying at elevated temperatures and chemical drying at low temperature. Six coals from lignite to high volatile bituminous rank were studied. Laboratoryscale liquefaction experiments were carried out on premoisturized and dried coals to determine the effects of different drying methods on liquefaction yields. Solid-state nuclear magnetic resonance (NMR) and swelling measurements were made to assess any changes in coal structure brought about by the different methods of drying. The NMR measurements showed that, in general, there were no major structural changes in coals dried thermally or with microwaves other than partial decarboxylation. Chemically dried coals exhibited increased resolution in the aliphatic carbon region that was attributed to adsorbed methanol, which was a reaction product as well as solvent for the chemical drying method. The swelling ratios of thermally dried and microwave-dried coals were lower than those of premoisturized coals, indicating a greater degree of cross linking in coals dried using these methods. The swelling ratios of the chemically dried coals were greater than those of the premoisturized coals. Coals that were dried or partially dried thermally and with microwaves had lower liquefaction conversions than coals containing equilibrium moisture contents. However, chemically dried coals had conversions ranging from 11 to 60% greater than the premoisturized coals. The conversion behavior is consistent with changes in the physical structure and cross-linking reactions because of drying. Thermal and microwave drying appeared to cause a collapse in the pore structure, thus preventing donor solvents from contacting reactive sites inside the coals. Chemical dehydration did not appear to collapse the pore structure.

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