镜煤有机溶剂逐级抽提的甲烷吸附响应及其作用机理

Methane Adsorption Response of Stepwise-Solvent-Extracted Vitrains and Possible Driving Mechanism

利用二硫化碳、苯、丙酮和四氢呋喃对不同煤级5件镜煤样品逐级抽提,测试了原煤和抽余物对甲烷的吸附特性,分析了产生抽余物吸附性差异的动力学原因。研究发现,逐级抽提改变了镜煤的吸附性,改变方向和幅度取决于煤化作用程度的高低,第二次煤化作用跃变对抽余物吸附性的变化起着关键作用。研究认为,镜煤抽余物吸附性的改变可能起源于物理扩容和化学缩容两种主要机理。二硫化碳一级抽提对长焰煤—焦煤早期阶段煤样产生物理扩容效应,对焦煤后期—贫煤阶段煤样则产生化学缩容效应。苯二级抽提和四氢呋喃四级抽提对煤吸附性的损伤以化学缩容作用为主,丙酮三级抽提则主要表现为物理扩容效应。

Five sets of vitrain samples were extracted in stepwith organic solvents such as carbon disulfide, benzene, acetone and tetrahydrofuran. The isothermal methane adsorptivity of the raw and extracted samples was measured, and the dynamics of the adsorption differences among extracted samples were analyzed. It was found that the step extraction changes the adsorptivity but the change direction and magnitude depends on the coalification degree, in which the second coalification jump plays a key role on the adsorption change. It was suggested that the change may be originated in two major mechanisms, i.e., the physical expansion and chemical shrinkage of adsorption space. Carbon disulfide extraction produces a physical expansion effect to flame, gas and early coking coals but a chemical shrinkage effect to late coking coal and anthracite. Damage of the benzene and tetrahydrofuran extractions to the adsorptivity is mainly resulted from chemical shrinkage and the effect of acetone extraction is mainly expressed as the physical expansion.