温度对煤的瓦斯吸附性能影响的试验研究

通过实验研究了不同温度、不同瓦斯压力情况下，煤的瓦斯吸附性能的变化规律，得出了当温度、瓦斯压力变化时，煤的瓦斯吸附曲线以及吸附常数随温度变化的数学关系式，为研究瓦斯在煤层中的赋存和流动规律提供了物理基础。

基于晶格理论模型煤的瓦斯吸附性能预测

采用瓦斯吸附试验测试系统,在303、293 K对气肥煤、贫煤和无烟煤等进行瓦斯等温吸附试验,并基于晶格理论模型和某一温度下煤的吸附试验为依据,开展不同温度下煤的瓦斯吸附规律预测。结果表明:不同变质程度煤中游离瓦斯摩尔密度与吸附量存在线性关系。与瓦斯吸附等温线的实测结果相比,采用晶格理论模型预测得到不同变质程度煤的等温吸附曲线无论是趋势还是定量结果均十分吻合,相对误差均不超过3.8%。

不同粒度软煤与硬煤吸附性能差异性研究

为了研究不同粒度软硬煤的吸附性能差异,进行实验室模拟实验,采用高压容量法测定不同粒度软硬煤的吸附量和吸附常数,拟合出吸附等温曲线,分析了软硬煤的吸附性能差异性随粒度的变化规律。结果表明:随着粒度的减小软硬煤吸附常数a值均增大,增大的趋势随着粒度的减小而减小。软煤在<0.1 mm的粒度达到最大吸附量,而硬煤却在0.20~0.25 mm粒度时产生最大吸附量。粒度1~3 mm软煤的吸附等温曲线始终在硬煤之上,当粒度为0.20~0.25 mm和<0.1 mm时硬煤和软煤的吸附等温线有1个交点,硬煤的吸附量反超了软煤。比较软硬煤吸附差值,发现随着粒度的减小,软硬煤吸附量差距减小。

不同埋深煤体孔隙结构特征及瓦斯吸附特性研究

为研究同一煤层煤体孔隙结构及其瓦斯吸附性能与埋深的关系,通过等温吸附试验、低温N2吸附试验,测定了4个不同埋深煤样的瓦斯吸附量和孔容、孔比表面积等孔隙结构参数,应用孔隙分形理论研究了不同埋深煤样的分形特征,并确定了孔隙结构参数与吸附常数的关系。结果表明:随着埋深的增加,煤样的孔比表面积增加,瓦斯吸附量增加;4个煤样中埋藏最深的煤样较最浅煤样比表面积增加了1.2603 m^(2)/g,总孔容减小了0.0026 mL/g,瓦斯吸附量增加了67%,吸附饱和度降低了7.4%;吸附常数a与孔比表面积和分形维数的幂函数呈正相关关系,吸附常数b与吸附常数a呈幂函数关系。因此,可根据不同埋深煤样孔隙结构参数量化瓦斯吸附性能,为细化同一煤层瓦斯灾害防治方案提供了理论依据。

Effect of magma intrusion on the occurrence of coal gas in the Wolonghu coalfield

Chemical analysis, methane isothermal adsorption studies, and mercury porosimetry were performed on ten samples taken from the magma intrusion boundary in the Wolonghu coalfield. The physico-chemical properties of coals from the magma intrusion region are compared to those from the normal regions. The results show that the volatile content (Vad), the limiting adsorption constant (a), and the initial methane diffusion rate of samples from the magma intrusion region are generally smaller than those values from samples from the normal region. The number three coal sample from the magma intrusion region has a large vitrinite reflectance, well developed macropores, a small surface area, and weak methane adsorp- tion capacity. The number ten coal sample from the normal region has a small vitrinite reflectance, well developed micropores, a large surface area, and a strong methane adsorption capacity. The maceral of the coal samples from the magma intrusion region and the normal region are similar. The coal in the area near the magma intrusion boundary is rich in methane and is an area where coal and gas outbursts often occur.