油状大分子有机物对H型水合物稳定性的影响  

Effect of oily macromolecular organics on stability of structure H hydrate

作　　者：张锡彦 梁海峰[1] 邵伟强 张华 ZHANG Xiyan;LIANG Haifeng;SHAO Weiqiang;ZHANG Hua(College of Chemistry and Chemical Engineering,Taiyuan University of technology,Taiyuan 030024,Shanxi,China)

机构地区：[1]太原理工大学化学化工学院,山西太原030024

出　　处：《天然气化工—C1化学与化工》2022年第2期137-143,共7页Natural Gas Chemical Industry

基　　金：国家自然科学青年基金资助项目(51106104)。

摘　　要：H型水合物因储气容量大在天然气储运方面具有广阔的应用前景,然而严苛的热力学条件成为限制天然气水合物大规模储运和工业化应用的主要瓶颈。运用分子动力学模拟,在恒温恒压系综(NPT)下,分别研究了温度为290 K、300 K、310 K和320 K,压力为3 MPa和8 MPa条件下,环庚酮、甲基环己烷和环庚烷3种油状大分子有机物对H型甲烷(CH_(4))水合物模型稳定性的影响。通过分析最终构象、径向分布函数、均方位移和相对浓度等性质,研究了客体分子种类以及客体CH;分子数对H型甲烷水合物稳定性的影响。结果表明,在NPT系综下,3种油状大分子有机物对H型甲烷水合物稳定性影响顺序为环庚烷>甲基环己烷>环庚酮。当大笼(5^(12)6^(8))中大客体分子数不变时,水合物的稳定性随着大笼中CH_(4)分子数的增加而升高,每个大笼中存在4个CH_(4)分子的H型水合物稳定性最高。Structure H hydrate has broad prospects in natural gas storage and transportation due to its high gas storage capacity.However, the severe thermodynamic conditions have become the main bottleneck restricting the large-scale storage and transportation and industrial application of natural gas hydrate. By molecular dynamics simulation, the effects of three oily macromolecular organics,cycloheptanone, methylcyclohexane and cycloheptane, on the stability of structure H methane(CH_(4)) hydrate under ensemble constant temperature and pressure ensemble(NPT) at the temperature of 290 K, 300 K, 310 K and 320 K and the pressure of 3 MPa and 8 MPa were studied. The effects of guest molecules and the number of guest CH_(4)molecules on the stability of structure H methane hydrate were studied by analyzing the final conformation, radial distribution function, mean square displacement and relative concentration.The results show that under NPT ensemble, the order of influence of three oily macromolecular organics on the stability of structure H methane hydrates is cycloheptane > methylcyclohexane > cycloheptanone. When the number of large guest molecules in the big cage(5^(12)6^(8)) does not change, the stability of structure H hydrate increases with the increase of the number of CH_(4)molecules in the large cage. The structure H hydrate with 4 CH;molecules in each large cage is the most stable.

关 键 词：H型水合物 油状大分子有机物 稳定性 分子动力学 

分 类 号：TE8[石油与天然气工程—油气储运工程]