Experimental study of the effect of particle size on the oxidation heating process of coal

Abstract：In order to study the effect of particle size on oxidation heating process of coal, formation regularity of O₂, CO, C₂H₄and other gases in temperature-rising oxidation process of the coal samples with different particle sizes of five types in Liyang Mine, Lu'an Coal Group were studied.Oxygen consumption rate of coal samples with different particle sizes, the formation rate of CO, CO₂, C₂H₄gas and the judging index of coal spontaneous combustion tendency were calculated.The results showed that:the critical temperature of spontaneous combustion, dry cracking and gas formation rate of the coal seam were about 80 ℃, 135 ℃ and 160 ℃ respectively.From the initial stage to the dry cracking temperature section, total gas production of all coal samples changed a little at the beginning, and then the variety of gas production increased after exceeding the dry cracking temperature.Furthermore, with the decrease of coal sample particle size, the rate of change in gas generation rate increased.With the decrease of coal sample particle size, the oxygen reaction area of coal sample increased, while the temperature of intersection point decreased correspondingly.The particle size of coal sample had obvious influence on coal spontaneous combustion tendency.

Keyword：particle size;coal spontaneous combustion;oxidation heating;critical temperature;