在气脂煤中对CH4,CO2和H2O的吸附-扩散进行分子模拟研究
Jinzhang Jia1,2, Yinghuan Xing3,4, Bin Li5
1College of Safety Science and Engineering, Liaoning Technical University, Fuxin, 123000, China.
Scientific reports
|October 15, 2024
概括
这项研究揭示了甲 (CH4),二氧化碳 (CO2) 和水 (H2O) 在煤炭中如何吸附和扩散. 最有可能是CO2扩散,而H2O吸附是复杂的,而不是纯粹的物理.
科学领域:
- 计算化学和材料科学计算化学和材料科学
- 地质化学和能源资源.
背景情况:
- 了解煤炭中的气体吸附和扩散对于能源提取和碳封存至关重要.
- 煤炭中甲 (CH4),二氧化碳 (CO2) 和水 (H2O) 的微观动力学仍然不完全理解.
- 之前的研究往往缺乏详细的分子层面的洞察力,了解温度和压力的影响.
研究的目的:
- 为了澄清CH4,CO2,H2O在煤炭中的吸附和扩散的微观动态机制.
- 研究温度和压力对这些吸附和扩散特性的影响.
- 在特定的煤炭模型中比较CH4,CO2和H2O的吸附和扩散行为.
主要方法:
- 构建一个巨分子结构模型的Jixi气脂煤.
- 使用巨型法典蒙特卡洛 (GCMC) 和分子动力学 (MD) 模拟.
- 使用的材料工作室软件用于273.15313.15K的温度和0.0115MPa的压力的模拟.
主要成果:
- 气体吸附 (CH4,CO2,H2O) 随着压力增加,遵循兰迈尔I型异热体.
- 和吸附能力:CH4 (11.1814.37毫升/克),CO2 (20.4024.70毫升/克),H2O (66.6184.21毫升/克).
- 温度效应:随着温度的增加,CH4和CO2吸附率下降;H2O吸附率呈现复杂的模式 (增加然后减少).
- 相互作用能量:E (H2O) E (CO2) E (CH4)
- 扩散的激活能量:CH4 (12.20 kJ/mol),CO2 (3.36 kJ/mol),H2O (8.47 kJ/mol),表示CO2最容易扩散.
- 吸附机制:CH4和CO2呈现物理吸附;H2O吸附比纯粹物理更复杂.
结论:
- 煤炭对CH4,CO2和H2O的吸附和扩散特性受到压力和温度的显著影响.
- 在研究的气体中,二氧化碳由于其低激活能,具有扩散的可能性最高.
- H2O吸附与CH4和CO2不同,这表明煤炭基质内的相互作用机制不同.
相关概念视频
Molecular Comparison of Gases, Liquids, and Solids
40.7K
Particles in a solid are tightly packed together (fixed shape) and often arranged in a regular pattern; in a liquid, they are close together with no regular arrangement (no fixed shape); in a gas, they are far apart with no regular arrangement (no fixed shape). Particles in a solid vibrate about fixed positions (cannot flow) and do not generally move in relation to one another; in a liquid, they move past each other (can flow) but remain in essentially constant contact; in a gas, they move...
40.7K
Phase Diagrams
40.1K
A phase diagram combines plots of pressure versus temperature for the liquid-gas, solid-liquid, and solid-gas phase-transition equilibria of a substance. These diagrams indicate the physical states that exist under specific conditions of pressure and temperature and also provide the pressure dependence of the phase-transition temperatures (melting points, sublimation points, boiling points). Regions or areas labeled solid, liquid, and gas represent single phases, while lines or curves represent...
40.1K
Behavior of Gas Molecules: Molecular Diffusion, Mean Free Path, and Effusion
28.6K
Although gaseous molecules travel at tremendous speeds (hundreds of meters per second), they collide with other gaseous molecules and travel in many different directions before reaching the desired target. At room temperature, a gaseous molecule will experience billions of collisions per second. The mean free path is the average distance a molecule travels between collisions. The mean free path increases with decreasing pressure; in general, the mean free path for a gaseous molecule will be...
28.6K
Entropy and Solvation
7.0K
The process of surrounding a solute with solvent is called solvation. It involves evenly distributing the solute within the solvent. The rule of thumb for determining a solvent for a given compound is that like dissolves like. A good solvent has molecular characteristics similar to those of the compound to be dissolved. For example, polar solutions dissolve polar solutes, and apolar solvents dissolve apolar solutes. A polar solvent is a solvent that has a high dielectric constant (ϵ...
7.0K
Physical Properties Affecting Solubility
22.5K
Solutions of Gases in Liquids
As for any solution, the solubility of a gas in a liquid is affected by the attractive intermolecular forces between solute and solvent species. Unlike solid and liquid solutes, however, there is no solute-solute intermolecular attraction to overcome when a gaseous solute dissolves in a liquid solvent since the atoms or molecules comprising a gas are far separated and experience negligible interactions. Consequently, solute-solvent interactions are the sole...
As for any solution, the solubility of a gas in a liquid is affected by the attractive intermolecular forces between solute and solvent species. Unlike solid and liquid solutes, however, there is no solute-solute intermolecular attraction to overcome when a gaseous solute dissolves in a liquid solvent since the atoms or molecules comprising a gas are far separated and experience negligible interactions. Consequently, solute-solvent interactions are the sole...
22.5K
Van der Waals Equation
4.0K
The ideal gas law is an approximation that works well at high temperatures and low pressures. The van der Waals equation of state (named after the Dutch physicist Johannes van der Waals, 1837−1923) improves it by considering two factors.
First, the attractive forces between molecules, which are stronger at higher densities and reduce the pressure, are considered by adding to the pressure a term equal to the square of the molar density multiplied by a positive coefficient a. Second, the volume...
First, the attractive forces between molecules, which are stronger at higher densities and reduce the pressure, are considered by adding to the pressure a term equal to the square of the molar density multiplied by a positive coefficient a. Second, the volume...
4.0K


