10.6084/m9.figshare.6429083.v1 Fengfeng Gao Fengfeng Gao Krishna M. Gupta Krishna M. Gupta Shiling Yuan Shiling Yuan Jianwen Jiang Jianwen Jiang Decomposition of CH<sub>4</sub> hydrate: effects of temperature and salt from molecular simulations Taylor & Francis Group 2018 CH4 hydrate decomposition temperature salt molecular simulation 2018-06-04 12:38:20 Dataset https://tandf.figshare.com/articles/dataset/Decomposition_of_CH_sub_4_sub_hydrate_effects_of_temperature_and_salt_from_molecular_simulations/6429083 <p>We report a molecular simulation study to investigate the decomposition of CH<sub>4</sub> hydrate. The decomposition is revealed to be stepwise from the outer to inner layers. Upon decomposition, the number of 5<sup>12</sup>6<sup>2</sup> cages drops faster than that of 5<sup>12</sup> cages. CH<sub>4</sub> molecules are released, dissolved in water, then enter gas phase; meanwhile, CH<sub>4</sub> bubbles may form particularly at a high temperature. Based on the variations of potential energy, order parameter, cage number and density profile of CH<sub>4</sub> at different temperatures (300, 330, 345 and 360 K) and NaCl concentrations (0, 0.6 and 1.8 M), the effects of temperature and salt are comprehensively examined. With increasing temperature, the decomposition in pure water is accelerated, whereas two opposite effects are observed in NaCl solution. At 330 K, the decomposition is retarded at a higher NaCl concentration, as attributed to the reduced CH<sub>4</sub> solubility in NaCl solution and the participation of ions in cage formation; at 360 K, however, the decomposition is accelerated when NaCl concentration increases due to bubble formation. This simulation study provides microscopic insights into hydrate decomposition, which might be useful towards the optimisation of operating conditions for CH<sub>4</sub> production from CH<sub>4</sub> hydrate.</p>