The estimation of the kinetic parameters of low-temperature coal oxidation

Abstract

Coals self-heating reasoned by their oxidation processes often could cause spontaneous combustion that may occur during all the stages of coal production, storage, transportation and utilization. The steady-state method enables determination of the critical ambient temperature, above which spontaneous combustion occurs, as a function of the reactor’s size. These critical ambient temperatures are used to calculate the kinetic constants of oxidation coal. The transient method (or Chen method) is applied to directly estimate the rate of oxidation by determining the crossing point, when the thermal conduction term near the center of a cylinder becomes zero. A modified method is proposed for determining the kinetic constants of coal oxidation from the steady-state heating temperature at the center of the reactor. The method is based on the dependence of the dimensionless temperature on the Frank-Kamenetskii parameter. The kinetic constants have been calculated from the results of a numerical experiment with a cylindrical reactor.