显微激光拉曼光谱原位观测甲烷水合物生成与分解的微观过程  

In situ Raman Spectroscopic Observation of Micro-Processes of Methane Hydrate Formation and Dissociation

作　　者：刘昌岭[1,2] 业渝光[1,2] 孟庆国[1] 吕万军[3] 王菲菲[3] 

机构地区：[1]国土资源部海洋油气资源和环境地质重点实验室,山东青岛266071 [2]青岛海洋地质研究所,山东青岛266071 [3]中国地质大学(武汉)资源学院,湖北武汉430074

出　　处：《光谱学与光谱分析》2011年第6期1524-1528,共5页Spectroscopy and Spectral Analysis

基　　金：国家重点基础研究发展计划项目(2009CB219503);国土资源部公益性行业科研专项经费项目(200911043-21);国土资源部油气资源与环境重点实验室开放基金重点项目(MRE200901)资助

摘　　要：采用显微激光拉曼光谱技术对高压透明毛细管中甲烷水合物的生成与分解的微观过程进行了原位观测,初步探讨了甲烷水合物笼型结构的变化规律。结果表明,甲烷水合物在生成过程中,甲烷分子的拉曼峰(2 917 cm-1)逐渐分裂为两个峰(2 905和2 915 cm-1),表明溶解态甲烷分子从单一的化学环境进入了两个有差异的化学环境中,这两个峰分别代表着水合物的大笼和小笼。同时,水的氢键作用由其液态向固态的转化而得到加强,使O—H键伸缩振动向低波数迁移。在甲烷水合物的分解过程中,大小笼中甲烷分子的拉曼双峰逐渐消解,并最终转化成单一的甲烷气体峰。显微激光拉曼光谱可以准确捕捉水合物生成与分解过程中其笼型结构变化的相关信息。Micro laser Raman spectroscopic technique was used for in situ observation of the micro-processes of methane hydrate formed and decomposed in a high pressure transparent capillary.The changes in clathrate structure of methane hydrate were investigated during these processes.The results show that,during hydrate formation,the Raman peak（2 917 cm-1）of methane gas gradually splits into two peaks（2 905 and 2 915 cm-1） representing large and small cages,respectively,suggesting that the dissolved methane molecules go into two different chemical environments.In the meantime,the hydrogen bonds interaction is strengthened because water is changing from liquid to solid state gradually.As a result, the O—H stretching vibrations of water shift to lower wavenumber.During the decomposition process of methane hydrates,the Raman peaks of the methane molecules both in the large and small cages gradually clear up,and finally turn into a single peak of methane gas.The experimental results show that laser Raman spectroscopy can accurately demonstrate some relevant information of hydrate crystal structure changes during the formation and dissociation processes of methane hydrate.

关 键 词：甲烷水合物 激光拉曼光谱 高压毛细管 生成与分解 

分 类 号：O657.3[理学—分析化学]