Kinetic parameters associated with self-heating of New Zealand coals under adiabatic conditions

摘要

Adiabatic self-heating tests were carried out on five New Zealand coal samples ranging in rank from lignite to high-volatile bituminous. Kinetic parameters of oxidation were obtained from the self-heating curves assuming Arrhenius behaviour. The activation energy E (kJ mol~(-1)) and the pre-exponential factor A (s~(-1)) were determined in the temperature range of 70-140 deg. The activation energy exhibited a definite rank relationship with a minimum E of 55 kJ mol~(-1) occurring at a Suggate rank of approx 6.2 corresponding to subbituminous C Either side of this rank there was a noticeable increase in the activation energy indicating lower reactivity of the coal. A similar rank trend was also observed in the R_(70) self-heating rate index values that were taken from the initial portion of the self-heating cure from 40 deg to 70 deg. From these results it is clear that the adiabatic method is capable of proving reliable kinetic parameters of coal oxidation.