中阶构造煤等温吸附/解吸特征及机理  

Isothermal Adsorption/Desorption Characteristics, and Mechanism of Tectonically Deformed Medium-rank Coals

作　　者：王琳琳[1,2] 龙正江 朱冠宇 WANG LinLin;LONG ZhengJiang;ZHU GuanYu(Low Carbon Energy Institute,China University of Mining and Technology,Xuzhou,Jiangsu 221008,China;Jiangsu Key Laboratory of Coal-Based Greenhouse Gas Control and Utilization,Xuzhou,Jiangsu 221008,China;School of Resources and Geosciences,China University of Mining and Technology,Xuzhou,Jiangsu 221116,China)

机构地区：[1]中国矿业大学低碳能源研究院,江苏徐州221008 [2]江苏省煤基温室气体减排与资源化利用重点实验室,江苏徐州221008 [3]中国矿业大学资源与地球科学学院,江苏徐州221116

出　　处：《沉积学报》2022年第1期60-72,共13页Acta Sedimentologica Sinica

基　　金：国家自然科学基金(41702169);中国博士后科学基金(2019M662013)~~。

摘　　要：选择四个不同变形程度的中阶煤样品作为研究对象,通过开展煤样的等温CH4吸附/解吸实验、X射线衍射(XRD)和傅里叶变换红外光谱(FT-IR)测试分析,研究了构造煤等温吸附/解吸性随煤变形程度的演化特征及其地球化学机理。结果表明,构造煤等温CH4吸附和解吸曲线随压力升高均呈现先快速增大后逐渐稳定的变化趋势,符合I型等温线特征,且均满足Langmuir模型,Langmuir体积随煤变形程度的增强总体呈增大的变化趋势,吸附/解吸迟滞程度则规律性降低。随煤变形程度的增强,芳香层面网间距呈逐渐减小的趋势,单元延展度则逐渐增大,单元堆砌度和堆砌层数表现出阶段性变化,煤晶核横向上的应力敏感性比纵向上强,受构造变形的控制更为明显;芳核C=C骨架呈明显增大趋势,芳环缩合程度较原生结构煤有所增高,而部分脂族类结构和C=O结构呈现规律性地降低。在构造煤变形过程中,煤芳构结构重排、大分子结构定向化程度升高、有序度增加,这种煤晶核短程有序性的增加有助于提高煤对CH4分子的吸附作用力,同时构造应力主要通过影响大分子结构侧链和含氧官能团的变化控制其吸附性。Four medium-rank coal samples with different degrees of tectonic deformation were studied to determine their isothermal adsorption/desorption evolution and geochemical mechanisms in isothermal CH4 adsorption/desorption experiments,X-ray diffraction(XRD)and Fourier transform infrared spectroscopy(FT-IR)tests. It was found that their isothermal CH4 adsorption and desorption curves showed a trend of initial rapid increase,gradually stabilizing with increasing pressure. This is consistent with the characteristics of a type I isotherm and the Langmuir model.With increasing coal deformation,the Langmuir volume had an increasing trend,and the degree of adsorption/desorption hysteresis decreased steadily. With increasing deformation,the dimension of the aromatic layer network gradually decreased and the unit extendability gradually increased. The unit stacking degree and the number of stacking layers changed in stages during deformation of the coal. The stress sensitivity of the coal crystal nucleus was stronger in the transverse direction than in the longitudinal direction,and was therefore affected more obviously by structural deformation. At the same time,with increasing deformation,the aromatic C=C skeleton clearly increased. The degree of condensation of the aromatic ring was higher than in the initial structure of the coal,while some aliphatic structures and the C=O structure steadily decreased. With increasing deformation,the rearrangement of aromatic structure,the degree of orientation of the macromolecular structure,and the degree of ordering all increased. The increase in shortrange ordering of the coal crystal nucleus helps to improve the adsorption force of coal to CH4 molecules,and the structural stress mainly affects adsorptive capacity by changing the side chains of the macromolecular structure and oxygen-containing functional groups.

关 键 词：中煤级 构造煤 吸附/解吸 变形程度 化学结构 

分 类 号：P618.11[天文地球—矿床学]