Solubility of Aqueous Methane under Metastable Conditions:Implications for Gas Hydrate Nucleation
作者单位：Key Laboratory of the Earth's Deep InteriorInstitute of Geology and GeophysicsChinese Academy of Sciences Centre for Scientific Computing and Department of ChemistryUniversity of WarwickCoventry CV4 7ALUnited Kingdom
会议名称：《中国科学院地质与地球物理研究所2013年度（第13届）学术年会》
会议日期：2014年
学科分类：08[工学] 0824[工学-船舶与海洋工程]
基 金：supported by the National Basic Research Program of China(i.e.,Program 973) via Grant 2009CB219503 the Chinese Academy of Sciences via Grant KZCX2-EW-118
摘 要：To understand the prenudeation stage of methane hydrate formation,we measured methane solubility under metastable conditions using molecular dynamics simulations. Three factors that influence solubility are considered:temperature, pressure,and the strength of the modeled van der Waals attraction between methane and ***,the naturally formed water cages and methane dusters in the methane solutions are analyzed. We find that both lowering the temperature and increasing the pressure increase methane solubility,but lowering the temperature is more effective than increasing the pressure in promoting hydrate nucleation because the former induces more water cages to form while the latter makes them less *** an increase in methane solubility,the chance of forming large methane clusters increases,with the distribution of cluster sizes being *** critical solubility,beyond which the metastable solutions spontaneously form hydrate,is estimated to be～0.05 mole fraction in this work,corresponding to the concentration of 1.7 methane molecules/*** value agrees well with the cage adsorption hypothesis of hydrate nucleation.