Abstract
In the present study, the weight loss by pyrolysis with increasing temperature was measured by TGA under atmospheric (0.1 MPa) and reduced (10-30 Pa) pressures of nitrogen for Japanese Miike, Akabbira, Taiheiyo coals. The reducedpressure condition was employed to minimize the effects of intra-particle secandary reactions, in addition to the conventional atmospheric pressure condition.
The activation energy and frequency factor obtained by analysis of the data with various heating rates assuming the first order reaction kinetics for each coal were almost kept constant respectively at the temperature range where the rate of weight loss was large, while the values were quite different among coals and between pressure condi-tions. The effects of mass transfer were suggested to be remarkable under the atmos-pheric pressure.
