Study on Dynamic Parameters of Coal Oxidation in Lower Temperature Varying with Particle Size by Means of Programmed Heating Experiment

The effect of particle size on spontaneous combustion parameters like reaction rate of coal with oxygen is tremendous. However, up to now, seldom is there any report on the relation between kinetic parameters of coal oxidation and particle size. By means of programmed heating experiments, oxygen consumption rate of coal with different particle size is determined, pre-exponential factors and activation energy of the coal samples are calculated through regression analysis, and relationship between particle size and kinetic parameters is determined eventually. Pre-exponential factor and activation energy increase as particle size of the coal samples react with oxygen increases. As particle size decreased from a larger diameter to the smaller one below 3 millimeter, activation energy and pre-exponential factors increase suddenly. It proved that self-ignition of coal depends on the proportion of the coal particle smaller than 3 millimeter rather than the average particle size.