基于单层吸附理论不同温度下煤层气等温吸附特性

摘要

In order to describe the adsorption characteristics of coal on methane more accurately,based on conventional isothermal adsorption test,methane adsorption capacity of coal was modified,and the calculation of apparent and true adsorption volumes were introduced,besides,the differences between apparent and true adsorption volume were compared,and the effect of tcmperature on such differences was analyzed,according to the true adsorption volumes,and then the fitted formulas between adsorption constant and temperature was established.The results showed that:the differences between apparent and true adsorption volumes became much more significant with the rising temperatures.When temperature reached 90℃,the error between apparent adsorption and true adsorption volume was maximum,8％.The adsorption ability of coal was proportional to the specific surface,when temperature rose,due to the increase of specific surface area,the adsorption ability of coal presented a linear growth with temperature.Such research results can help to understand the adsorption properties of lump coals,and provided appropriate guidance in exploitation technique of coalbed methane (CBM).%为了更准确地描述煤体对甲烷的吸附特性,基于常规等温吸附试验,对煤体甲烷吸附量进行了修正,引入了真实吸附量和视吸附量的计算方法,对比分析了视吸附量和真实吸附量之间的差异以及温度对二者差异性的影响;并以真实吸附量为基础,得到饱和吸附量和温度间的函数关系.结果表明:真实吸附量和视吸附量之间的差异会随着温度升高而逐渐显著,90℃时,二者差异最大,可达8％;煤体的吸附能力与其比表面积成正比,随着温度升高,因煤体比表面积不断增大,饱和吸附量随温度呈线性规律增长.研究结果可为正确认识煤体对煤层气的吸附特性及煤层气资源的开发利用提供参考.