Ignition and combustion of large coal particles in cold nitrogen–oxygen mixtures

Forced ignition and subsequent combustion of large coal particles in a cold air and oxygen are investigated experimentally. The critical value of the initial temperature (ignition temperature) of a particle of charcoal and of anthracite is estimated. On preliminary heating of the particle above the ignition temperature, a quasi-stationary mode of combustion is attained after a certain interval of time. For a charcoal particle, depending on the initial density of the particle, either a substantial change in its density or its invariability in the process of combustion in a cold air fl ow is observed. A relation is suggested allowing one to estimate the critical temperatures of ignition in cold gaseous mixtures depending on oxygen concentration and particle diameter. The absence of ignition of a large anthracite particle in air at room temperature is attributed to the larger value of the activation energy there than in the charcoal particle.
Forced ignition and subsequent combustion of large coal particles in a cold air and oxygen are investigated experimentally. The critical value of the initial temperature (ignition temperature) of a particle of charcoal and of anthracite is estimated. On preliminary heating of the particle above the ignition temperature, a quasi-stationary mode of combustion is attained after a certain interval of time. For a charcoal particle, depending on the initial density of the particle, either a substantial change in its density or its invariability in the process of combustion in a cold air fl ow is observed. A relation is suggested allowing one to estimate the critical temperatures of ignition in cold gaseous mixtures depending on oxygen concentration and particle diameter. The absence of ignition of a large anthracite particle in air at room temperature is attributed to the larger value of the activation energy there than in the charcoal particle.
Author:  A. S. Chernenko and V. V. Kalinchak
Keywords:  coal particle, forced ignition, fi ring, combustion, cold gaseous mixtures, oxygen
Page:  357-364