Cage occupancy of methane hydrates from Gibbs ensemble Monte Carlo simulations
Cage occupancy of methane hydrates from Gibbs ensemble Monte Carlo simulations
复制标题
DOI：
10.1016/j.fluid.2015.10.005
复制
发表时间：
2016-04-15
影响因子：
2.6
通讯作者：
Yasuoka, Kenji
中科院分区：
文献类型：
--
作者：
Brumby, Paul E.;Yuhara, Daisuke;Yasuoka, Kenji
等压-等温Gibbs系综蒙特卡罗模拟计算了sI甲烷水合物与体积甲烷的平衡状态，计算了大笼占有率和小笼占有率。ops联合原子Lennard-Jones势及其变体用于模拟甲烷，而TIP4P/Ice模型用于模拟水。与Henley和Lucia b[1]使用TIP4P-Ew水和trap - ua甲烷进行的模拟相比，该模型系统产生的笼中总占有率更高。我们也看到了比Uchida等人先前的拉曼光谱研究中观察到的更高的总占用量，但在大笼占用量方面发现了很好的一致性。模拟提供了在温度和压力分别为270-290 K和20 - 400 bar范围内的大笼和小笼占用率的全面预测。这些预测证明了Gibbs系综在包合物水合物模拟中的优势；控制温度和压力的能力，而不限制水合物相的化学成分是这个集合的关键优势。(C) 2015 Elsevier B.V.版权所有
Isobaric-isothermal Gibbs ensemble Monte Carlo simulations of sI methane hydrates in equilibrium with bulk methane are performed to calculate large and small cage occupancies. The OPLS united-atom Lennard-Jones potential, and a variation, are used to model methane, while the TIP4P/Ice model represents water. This model system produces systematically higher total cage occupancies than those of simulations by Henley and Lucia [1] using TIP4P-Ew water and TraPPE-UA methane. We also see higher total occupancies than those observed in prior Raman spectrometry studies by Uchida et al. [2], but find good agreement for large cage occupancies. The simulations provide comprehensive predictions of large and small cage occupancies for temperatures and pressures within the ranges 270-290 K and 20 400 bar, respectively. These predictions demonstrate the advantages of the Gibbs ensemble for the simulation of clathrate hydrates; the ability to control the temperature and pressure, while not constraining the chemical composition of the hydrate phase is the key advantage of this ensemble. (C) 2015 Elsevier B.V. All rights reserved.