Evaluation and development of special purpose coals. Final report. [73 refs. ; role of maceral composition in gasification and liquefaction; Penn State data collection]

Two hundred eighty-six coals from throughout the nation have been sampled and analyzed. Trends in the maceral contents of U.S. coals with respect to geographic location exist. Younger, western coal basins show higher resinite contents than eastern coals. The nature and amount of mineral matter and major and trace elements varies widely, even within a given coal seam. A minimum for the Hardgrove Grindability of American coals occurs when volatile matter is approximately equal to 50%. Coals are most friable when volatile matter nears 20%. Fractionation studies of coals indicate that specialized feedstocks for conversion processes are feasible. DryFlo separations resulted in significant ash and S reductions. Optimum yields in batch autoclave liquefaction tests occurred with coals of the high volatile bituminous rank and where concentrations of vitrinite and exinite were high. The pore structure of coals varies with rank. Gasification results in an expansion of the pore structure of coals and chars. Gasification rates of coal chars depend on: (1) active carbon site concentration, (2) accessibility of active sites to reactants, and (3) catalytic impurities. In a mass spectrometric analysis of the pyrolysis products of coal, the ratio of unsaturated to saturated aliphatic products increased during the course of pyrolysis, while the ratio of aromatic to aliphatic products decreased; both ratios increased with increasing temperature.In a comparison of conventional and continual mining sections of a West Virginia coal mine, the conventionally mined coal had a greater size consist than the continually mined coal; clean coal yield was also greater.