Molecular simulation study on the influence of different temperatures and moisture contents on the adsorption characteristics of anthracite

IF 2 3区化学 Q4 CHEMISTRY, PHYSICAL

Chemical Physics Pub Date : 2025-04-05 DOI:10.1016/j.chemphys.2025.112727

Mingyun Tang , Dingzhu Gong , Yanke Chen , Jinwei Qiu , Yingdi Yang , Ruiqing Zhang , Shiqiang Gao

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Abstract

The efficient development of coalbed methane (CBM) and CO₂ geological sequestration technologies plays a critical role in achieving a clean energy transition. However, the microscopic mechanisms underlying the effects of temperature and moisture on the adsorption characteristics of anthracite remain unclear. This study investigates the effects of temperature and moisture content on the adsorption characteristics of anthracite, using samples from the Yangquan mining region in Shanxi, China. A three-dimensional molecular model of anthracite was developed using the molecular dynamics (MD) simulation method. By contrasting the simulation outcomes with data from the CH₄ adsorption experiment, the reliability of the model was confirmed. The amount of adsorption, heat of adsorption, and diffusion coefficients of CO₂ and CH₄ in anthracite were examined using the Grand Canonical Ensemble Monte Carlo (GCMC) simulation method at temperatures between 293.15 and 333.15 K and moisture levels between 0 % and 3.20 %. The findings indicate that the simulated Langmuir volume for gas adsorption exceeds the experimental measurements, exhibiting a relative error of 4.3 %. Under varying temperatures and moisture contents, the gas adsorption isotherms followed the Langmuir type I model. The adsorption constants (a and b) are negatively correlated with the moisture content and temperature. At identical temperature and moisture content, the adsorption quantities of the two gases, heat of adsorption, and diffusion coefficient are related in the following way: CO₂ > CH₄. In dry circumstances, as the temperature rose, the diffusion coefficient rose, and the quantity and heat of gas adsorption on coal dropped. As the water content of coal increased, the quantity of gas that coal could adsorb and its diffusion coefficients decreased. However, adsorption heat increased with rising coal moisture content. This study provides a theoretical foundation for systematically understanding the adsorption characteristics of coalbed methane (CBM) on high-rank coal surfaces.

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不同温度和含水率对无烟煤吸附特性影响的分子模拟研究

煤层气和二氧化碳地质封存技术的高效开发对实现清洁能源转型至关重要。然而，温度和湿度对无烟煤吸附特性影响的微观机制尚不清楚。以山西阳泉矿区为研究对象，研究了温度和含水率对无烟煤吸附特性的影响。采用分子动力学（MD）模拟方法建立了无烟煤的三维分子模型。将模拟结果与CH4吸附实验数据进行对比，验证了模型的可靠性。在温度为293.15 ~ 333.15 K、湿度为0% ~ 3.20%的条件下，采用大典型系综蒙特卡罗（GCMC）模拟方法研究了CO2和CH4在无烟煤中的吸附量、吸附热和扩散系数。结果表明，模拟气体吸附的Langmuir体积超出了实验测量值，相对误差为4.3%。在不同温度和含水率下，气体吸附等温线符合Langmuir I型模型。吸附常数a和b与温度和含水率呈负相关。在相同的温度和含水率下，两种气体的吸附量、吸附热和扩散系数的关系式如下：CO2 >；甲烷。在干燥情况下，随着温度的升高，扩散系数增大，煤对气体的吸附量和吸附热下降。随着煤含水量的增加，煤的吸附气量和扩散系数减小。吸附热随煤含水率的升高而增大。该研究为系统认识煤层气在高煤阶煤表面的吸附特性提供了理论基础。

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来源期刊

Chemical Physics 化学-物理：原子、分子和化学物理

CiteScore

4.60

自引率

4.30%

发文量

278

审稿时长

39 days

期刊介绍： Chemical Physics publishes experimental and theoretical papers on all aspects of chemical physics. In this journal, experiments are related to theory, and in turn theoretical papers are related to present or future experiments. Subjects covered include: spectroscopy and molecular structure, interacting systems, relaxation phenomena, biological systems, materials, fundamental problems in molecular reactivity, molecular quantum theory and statistical mechanics. Computational chemistry studies of routine character are not appropriate for this journal.