Abstract: In order to study the influences of water soaking-drying on the coal spontaneous combustion characteristics,coal samples were treated by using both the vacuum drying method and the natural drying method after water soaking to form two-treated coal samples.Temperature-programming experiments were carried out on both the raw coal sample and the two-treated coal samples to measure volume fractions of the CO and C₂H₄ generated in oxidation process.The spontaneous combustion characteristic temperatures were calculated in light of the change point of CO volume fraction growth rate and C₂H₄ generation temperature of the three coal samples,and the influences of water soaking-drying on the spontaneous combustion characteristic temperature of three coal samples were analyzed.The oxygen consumption rate and exothermal strength were calculated by the oxidative exothermic formulas,and the influences of water soaking-drying on oxidative exothermic performance of three coal samples were analyzed.At last,the influence of water soaking-drying on the Graham coefficient R₂ or R₃ or alkane ratio for prediction accuracy of the coal spontaneous combustion characteristic temperature was analyzed.The experimental researches show that water soaking-drying will change coal spontaneous combustion characteristics,increase the characteristic temperature of coal spontaneous combustion and reduce coal oxidative exothermic performance,Graham coefficient R₂ or R₃ for prediction accuracy of the coal spontaneous combustion characteristic temperature will be decreased by water soaking-drying,and as alkane ratio,the prediction accuracy will be less affected by water soaking-drying.

Key words: water soaking-drying, coal spontaneous combustion characteristics, critical temperature, oxidative exothermic performance, predictive index