The report gives results of a study of the evolution of volatile matter from coals of various rank during fixed-and fluid-bed pyrolysis. The pyrolyses were performed at temperatures ranging from 400 to 1000 C and with heating rates ranging from 1.5 to 6.0 C/s. Effects of equilibrium temperature, heating rate, coal rank, and reactor design on weight loss, elemental volatilization, gas species production and product composition, and tar/gas production ratios were examined. Lignite, sub-bituminous, and bituminous coals exhibited the same weight loss versus temperature profiles at slow pyrolysis rates. Toluene, xylene, ethane, and total sulfur yields versus temperature varied from fixed-to fluid-bed conditions. All other compounds measured showed no such dependence on reactor design. For all systems studied, tar-to-gas ratios were lower (although overall weight losses were greater) for slow pyrolysis than for rapid pyrolysis. Tar yields increased and carbon oxide yields decreased with increasing coal rank.

Caption title. "August 1984." "EPA-600/7-84-082." Microfiche.