Clean, premium-quality chars: Demineralized and carbon enriched. Final technical report, 1 September, 1992--31 August, 1993

摘要

The overall objective of this two-year project was to evaluate methods of preparing demineralized and carbon enriched chars from Illinois Basin coals. The two processing steps, physical cleaning and devolatilization under different environments, led to the following results. Cleaning coal incompletely removes mineral matter which decreases catalytic activity and increases micropore structure. Water forms hydrogen bonds to oxygen functional groups in coal, and during drying, coals undergo structural changes which affect mild gasification. When methane reacts wit coal, devolatilization and carbon deposition occur, the rates of which depend on temperature and amount of ash. Thermal decomposition of IBC-101 coal starts at 300 C, which is much lower than previously believed, but maximum yields of liquids occur at 500 C for IBC-101 coal and at 550 C for IBC-102 coal. Aliphatic-to-aromatic ratios increase with increasing pyrolysis temperatures to 300 C and then decrease; therefore, liquids formed during gasification of 550 C or higher contain mainly aromatic compounds. Btu values of chars are higher after methane treatment than after helium treatment. (ERA citation 19:011452)