分子动力学模拟CO2水合物的三相平衡线与OPC水模型
Xiluo Hao1,2, Chengfeng Li1,2, Qingguo Meng1,2
1Key Laboratory of Gas Hydrate, Ministry of Natural Resources, Qingdao Institute of Marine Geology, Qingdao 266071, China.
ACS omega
|October 30, 2023
概括
分子动力学模拟确定了二氧化碳 (CO2) 水合物共存线. 经过调整的Lorentz-Berthelot参数的TIP4P/冰水模型与实验数据有很好的一致性,改善了CO2水合物预测.
科学领域:
- 热力学是一种热力学.
- 计算化学计算化学
- 材料科学 材料科学 材料科学
背景情况:
- 准确预测二氧化碳 (CO2) 水合物相位平衡对于CO2地质储存和天然气生产等应用至关重要.
- 分子动力学 (MD) 模拟为研究水合物形成提供了强大的工具,但需要精确的力场参数.
研究的目的:
- 通过MD模拟来确定三相 (CO2水合物-液态水-CO2蒸汽) 的共存线.
- 评估不同水模型和洛伦茨-伯塞洛特 (LB) 混合规则对二氧化碳水化合物平衡预测准确性的影响.
- 为了确定最佳的模拟参数,可靠地预测二氧化碳水合物形成条件.
主要方法:
- 在3到500MPa的压力范围内,对CO2水合物系统进行了MD模拟.
- 经典和修改的LB参数被用于模拟水 (OPC和TIP4P/冰模型) 和CO2 (EPM2模型) 之间的相互作用.
- 模拟结果与实验数据进行了比较,以评估预测的准确性.
主要成果:
- 使用OPC水模型的模拟显示了与实验数据的负偏差,无论LB参数的选择如何.
- TIP4P/冰水模型,LB参数调整为CO2溶解度,与实验平衡数据有很好的一致性.
- 水模型的选择显著影响了平衡预测,而不是二氧化碳模型.
- 准确地预测三相平衡 (T3) 取决于同样依赖于H2O-H2O和H2O-CO2相互作用参数.
- 结合TIP4P/冰水和EPM2 CO2与修改的LB参数的组合,为T3预测提供了最高的准确性.
结论:
- 推使用TIP4P/冰水模型,加上优化的LB参数,用于精确的二氧化碳水化合物平衡的MD模拟.
- 准确预测二氧化碳水合物形成需要对水和交叉相互作用潜力进行仔细的选择和参数化.
- 这些发现为改善水合物系统中CO2/CH4替换过程的MD模拟提供了宝贵的见解.
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