New insights into decomposition characteristics of nanoscale methane hydrate below the ice point

• Published in: RSC Advances
• Main Authors: Wan, Lihua, Liang, Deqing, Guan, Jinan
• Format: Report
• Language: English
• Published: ROYAL SOC CHEMISTRY 2018
• Subjects: NATURAL-GAS; ANOMALOUS PRESERVATION; MOLECULAR-DYNAMICS; SUPERCOOLED WATER; CRYSTAL-STRUCTURE; CH4 HYDRATE; DISSOCIATION; CARBON; EVOLUTION; LIQUID; Chemistry; Multidisciplinary; Broad Peak; Ice Point; Methane hydrate
• Online Access: http://ir.giec.ac.cn/handle/344007/24355; https://doi.org/10.1039/c8ra08955h

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(-3). The X-ray diffraction phase analysis showed that VHDA has a broad peak at 2 of around 30 degrees. 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.