Activated carbon produced from an Illinois basin coal

Activated carbons were produced from an Illinois Basin bituminous coal (IBC-106) by a three-step process: oxidation of the coal in air at 150-250 degrees C for 2-40 hours, devolatilization of these oxidized coals in nitrogen at 500-730 degrees C for 1 hour and activation (gasification) of the chars in 45% steam, 4% oxygen in nitrogen at 730-880 degrees C for 3.5-96 hours. Products were characterized in terms of CO2 single-point BET surface area, helium and bulk densities, pore volume and toluene adsorption capacity. Seven of the nine carbons produced had surface areas exceeding 1000 m(2) g(-1) (dry). It was confirmed that the application of oxidation pretreatment eliminates the caking of IBC-106, preserves the coal's microstructure, and leads to high carbon surface areas. In comparison with Darco coconut charcoal, a commercial activated carbon (Fisher Scientific) whose surface area was 547 m(2) g(-1) (dry), the largest toluene adsorption capacity of activated carbons was 1.57 g g(-1), four times more than that of Darco. Production costing analysis on a laboratory scale suggested that, in a single production run, the most cost-effective final product is not the activated carbon with maximum surface area but the carbon produced at the lowest cost for each square meter of pore surface area. (C) 1997 Elsevier Science Ltd.