不同浓度聚乙烯醇对甲烷水合物分解作用的分子动力学模拟  

Molecular Dynamic Simulation of Methane Hydrate Decomposition with Polyvinyl Alcohol at Different Concentrations

作　　者：陈玉娟[1] 王燕鸿[1] 樊栓狮[1] 郎雪梅[1] 

机构地区：[1]华南理工大学化学与化工学院传热强化与过程节能教育部重点实验室,广州510640

出　　处：《化学学报》2010年第22期2253-2258,共6页Acta Chimica Sinica

基　　金：国家重大科技专项(No.2008ZX05026-004-06);华南理工大学中央高校基本科研业务费专项资金(No.2009ZM0185);中国科学院广州天然气水合物研究中心开放基金(No.080757)资助项目

摘　　要：采用分子动力学方法,模拟了273.15K下聚乙烯醇(PVA)对甲烷水合物的分解作用.研究发现,PVA浓度为2.7wt%时,水分子始终在其平衡位置附近波动,扩散系数仅为1.04×10-11m2/s;PVA浓度为5.2wt%时,水合物笼型结构坍塌,水分子以液态水的形式存在,甲烷分子从孔穴中逸出,聚乙烯醇的羟基在分子内部形成氢键,形成团簇,产生空间位阻,阻止了水分子再生成水合物,水分子的扩散系数1.61×10-9m2/s;PVA浓度为7.6wt%时,甲烷水合物周围有部分笼型结构被破坏,部分甲烷分子从孔穴中逸出,水分子扩散系数为3.55×10-10m2/s.得出聚乙烯醇对甲烷水合物的分解作用大小为:5.2wt%>7.6wt%>2.7wt%,为PVA溶液促进甲烷水合物分解实验研究提供参考.Methane hydrate decomposition was investigated by molecular dynamic simulation adding with polyvinyl alcohol.Three kinds of methane hydrate systems with polyvinyl alcohol concentration of 2.7 wt%,5.2 wt%,7.6 wt% respectively were studied.Water moleculars in methane hydrate fluctuate near the equilibrium position when polyvinyl alcohol（PVA） concentration is 2.7 wt%,with diffusion coefficient 1.04× 10-11 m2/s;while at 5.2 wt% PVA solution,methane hydrate structure was disrupted,most methane escaped from the cages,with diffusion coefficient of water molecular 1.61×10-9 m2/s,showing good ability of hydrate decomposition.Hydrogen bond was observed between PVA itself,causing steric hindrance in hydrate formation.A small parts of methane hydrate cages at interface were disrupted,resulting some methane escaped,the diffusion coefficient of water molecular is 3.55×10-10 m2/s in 7.6 wt% PVA solution.As for effect on decomposition of methane hydrate,PVA concentration 5.2 wt% is the greatest,while the PVA concentration 2.7 wt% is the least.This work provides great reference value for the experimental investigation into the effect of PVA on the hydrate dissociation.

关 键 词：聚乙烯醇 甲烷水合物 分子动力学模拟 分解 

分 类 号：O632.3[理学—高分子化学]