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Molecular Dynamics Simulation of Methane Hydrate Decomposition in the Presence of Alcohol Additives
Author(s) -
Sun Xiaoliang,
Zhou Guanggang,
Zhu Jianwei,
Wu Haicheng,
Lu Guiwu,
Bai Dongsheng
Publication year - 2019
Publication title -
chemphyschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.016
H-Index - 140
eISSN - 1439-7641
pISSN - 1439-4235
DOI - 10.1002/cphc.201900742
Subject(s) - hydrate , methane , chemistry , decomposition , methanol , molecular dynamics , clathrate hydrate , aqueous solution , chemical process of decomposition , molecule , thermodynamics , chemical engineering , organic chemistry , computational chemistry , engineering , physics
Abstract The decomposition process of methane hydrate in pure water and methanol aqueous solution was studied by molecular dynamics simulation. The effects of temperature and pressure on hydrate structure and decomposition rate are discussed. The results show that decreasing pressure and increasing temperature can significantly enhance the decomposition rate of hydrate. After adding a small amount of methanol molecules, bubbles with a diameter of about 2 nm are formed, and the methanol molecules are mainly distributed at the gas‐liquid interface, which greatly accelerates the decomposition rate and gas‐liquid separation efficiency. The radial distribution function and sequence parameter analysis show that the water molecules of the undecomposed hydrate with ordered ice‐like configuration at a temperature of 275 K evolve gradually into a long‐range disordered liquid structure in the dynamic relaxation process. It was found that at temperatures above 280 K and pressures between 10 atm and 100 atm, the pressure has no significant effect on hydrate decomposition rate, but when the pressure is reduced to 1 atm, the decomposition rate increases sharply. These findings provided a theoretical insight for the industrial exploitation of hydrates.