煤岩组分对蓄热及自燃特性的影响

Influence of coal composition on heat storage and spontaneous combustion characteristics

基于采空区煤岩垮落特点,通过对煤岩混合组分热物性参数及氧化动力学分析,提出了垮落煤岩组分及混合岩性改变蓄热参数、温升氧化过程及活化能的观点。导热系数测定实验表明,煤中掺混上覆岩层后,随掺混比例增多,导热系数逐渐增大;且岩石组分含量>50%后,混合样品的导热系数增幅较大;上覆岩层岩性不同,混合组分差异明显,相同比例下,泥岩组分为50%样品的导热系数为0.12 W/(m·K)、粉砂岩组分为0.14 W/(m·K)。热重实验表明:岩石组分的增加导致失重速率的下降,主要特征温度点、活化能增大,其中粉砂岩组分活化能高于泥岩组分;此外,当煤岩组分<10%,活化能增幅较小;组分在10%~70%,泥岩组分活化能由28.18 kJ/mol增加到35.28 kJ/mol,活化能增幅较大,低于粉砂岩组分;煤岩组分>70%后,活化能增长趋势变缓。

Based on the caving characteristics of coal and rock in goaf,through the analysis of thermal physical parameters and oxidation kinetics of coal and rock mixed components,the viewpoint of changing thermal storage parameters,temperature rise oxidation process and activation energy of caving coal and rock components and mixed lithology is proposed.The thermal conductivity measurement experiment shows that the thermal conductivity increases gradually with the increase of mixing proportion after the overburden is mixed with coal;and the thermal conductivity of mixed samples increases greatly when the rock component content is more than 50%;the lithology of overburden is different,and the difference of mixed components is obvious.Under the same proportion,the thermal conductivity of 50%mudstone is 0.12 W/(m·K),and that of siltstone is 0.14 W/(m·K).Thermogravimetric test shows that the increase of rock composition leads to the decrease of weight loss rate,and the main characteristic temperature point and activation energy increase,in which the activation energy of siltstone component is higher than that of mudstone component;in addition,when the composition of coal and rock is less than 10%,the increase of activation energy is small;when the composition is between 10%and 70%,the activation energy of mudstone increases from 28.18 kJ/mol to 35.28 kJ/mol,the increase of activation energy is large,which is lower than that of siltstone.When the composition of coal and rock is more than 70%,the increase trend of activation energy becomes slow.