Experiment study on spontaneous combustion features of weathered coal under condition of high temperature oxidation

Deng Jun; Song Jiajia; Zhao Jingyu; Jiang Shangrong; Xiao Yang; Zhang Yanni

doi:10.13199/j.cnki.cst.2017.01.012

Abstract：In order to master a development evolution law of a seam outcrop fire,a high temperature programming rising experiment system was applied to simulate the high temperature oxidized spontaneous combustion process of the weathered coal and the macro spontaneous combustion features and the characteristic parameters in the normal temperature to 650 ℃ high temperature oxidized process were obtained.The increased rate analysis method of the index gas was applied to set up the weathred coal characteristic temperature point of the high temperature oxidation.The results showed that under the condition of the high temperature and low oxygen concentration,the weathered coal still could keep the oxidized reaction occurred and could release great heat to maintain the spontaneous combustion.The humic acid contained in the weathered coal would steadily occur the thermal decomposition reaction with the coal temperature increased and would cause CO2 、CH4 、C2H4 and C2H6 gas concentrations from the oxidation increased.Meanwhile,the CH4、C2H4 and C2H6 gas concentrations would be similar to the coal temperature variation law.Due to the weathered coal affected by the chemical weathered function,those three gas concentrations would be low at the low temperature stage and then could be increased with the temperature increased.In addition,the CO gas concentration occurred from the high temperature oxidation of the coal sample with a particle size less than 0.9 mm would have a high CO concentration generally than other particle size.From 400～590 ℃,when the particle size was 7～ 10 mm,CO concentration value from the high temperature oxidation of the coal sample would be minimum.