Wan Lihua, Liang Deqing, Guan Jinan
Key Laboratory of Gas Hydrate, Guangzhou Institute of Energy Conversion, Chinese Academy of Sciences Guangzhou 510640 People's Republic of China
RSC Adv. 2018 Dec 12;8(72):41397-41403. doi: 10.1039/c8ra08955h. eCollection 2018 Dec 7.
In this paper, molecular dynamics simulation was used to study the decomposition process of nanoscale methane hydrate at 1 atm and 227 K. The results predict that methane hydrate decomposes into supercooled water (SCW) and methane gas and the resulting SCW turns into very high density amorphous ice (VHDA). The density of the VHDA is as high as 1.2-1.4 g cm. The X-ray diffraction phase analysis showed that VHDA has a broad peak at 2 of around 30°. The VHDA encapsulates the methane hydrate crystal so that the crystal can survive for a long time. The dissolved gas from the hydrate melt cannot escape out of the VHDA in a short time. The simulation results reveal new molecular insights into the decomposition behaviour of nanoscale methane hydrate below the ice point.
在本文中，采用分子动力学模拟研究了纳米级甲烷水合物在1个大气压和227 K下的分解过程。结果预测，甲烷水合物分解为过冷水（SCW）和甲烷气体，生成的过冷水转变为超高密度非晶冰（VHDA）。超高密度非晶冰的密度高达1.2 - 1.4 g/cm。X射线衍射相分析表明，超高密度非晶冰在2θ约为30°处有一个宽峰。超高密度非晶冰包裹着甲烷水合物晶体，使晶体能够长时间存在。水合物熔体中的溶解气体在短时间内无法从超高密度非晶冰中逸出。模拟结果揭示了对冰点以下纳米级甲烷水合物分解行为的新分子见解。
