固体表面天然气水合物结晶的分子机理研究

项目名称： 固体表面天然气水合物结晶的分子机理研究

项目编号： No.41473063

项目类型： 面上项目

立项/批准年度： 2015

项目学科： 天文学、地球科学

项目作者： 梁帅

作者单位： 中国科学院广州能源研究所

项目金额： 80万元

中文摘要： 大量实验研究和工业生产实践表明，矿物质和油气管道表面对于天然气水合物结晶行为具有重要影响，但相关的分子机理尚不清楚。本项目拟采用分子动力学模拟方法，研究天然气水合物在二氧化硅、碳酸钙和氧化铁表面存在下形成和生长的分子机理，揭示固体表面的结构缺陷和化学性质对天然气水合物形成和生长行为的影响，从固液界面的分子结构和动力学方面丰富和完善经典异相结晶理论。我们将通过天然气水合物分子结构、能量以及动力学等多种有序参数表征和分析体系的相转变行为，统计水合物形成的速率、位置和晶核结构，并与均相结晶行为进行比较从而揭示固体表面化学性质和结构缺陷对水合物形成和生长行为的影响。本项目将首次研究自然界中与天然气水合物广泛共存的碳酸钙和油气输运管道表面以及相应的表面结构缺陷对水合物形成和生长的影响，其成功实施将为我国加快开发和利用天然气水合物资源以及油气管道的安全运行提供基础理论支持。

中文关键词： 分子动力学模拟；天然气水合物；异相结晶理论；固液界面；新能源科学

英文摘要： Previous experimental studies and industrial practices suggest that mineral surfaces and oil/gas pipelines play a critical role in the gas hydrate formation processes, while the underlying molecular mechanisms remain unclear. By using molecular dynamics simulation methodology, this proposal intends to understand the molecular mechanisms of the gas hydrate formation and crystal growth behavior in presence of a foreign silica, calcium carbonate, or ferric oxide surface. We will try to understand the effects of surface properties, including structural defects and surface chemistry, on the behavior of gas hydrate formation. The observations from this study should be complementary to the framework of classical heterogeneous nucleation theory in terms of molecular kinetics and structures at the solid/liquid interfaces. A number of order parameters, including molecular structures, energy, and kinetics, will be used to study the phase transition processes, and determine the formation rate, the position, and the structure of the initial nuclei. The results will be compared to previous observations from homogeneous nucleation studies, aiming to reveal the influences of the solid surfaces. This study is the first to study the effects of calcium carbonate and ferric oxide surfaces, which are commonly coexisted with gas hydrates in the natural world or the oil/gas pipelines. The completion of the proposed work will be helpful in establishing a theoretical basis for gas sequestration from gas hydrate reserviors and oil/gas transportation through pipelines.

英文关键词： Molecular Dynamics Simulation;Gas Hydrate;Heterogeneous Nucleation Theory;Solid/Liquid Interface;New Energy Science