XIANG Xueni, HUANG Liang, ZHOU Wen, et al. Structural characteristics and gas storage properties of gas hydrates based on molecular simulation[J]. Petroleum Reservoir Evaluation and Development, 2022, (5): 825-832. DOI: 10.13809/j.cnki.cn32-1825/te.2022.05.015.
Structural characteristics and gas storage properties of gas hydrates based on molecular simulation
which is one of the most potential new energy resources with abundant resources. However
gas hydrate has not been exploited commercially at present
and its micro-structure characteristics and gas storage mechanism need to be clarified urgently. Based on the framework and guest molecular information of SI
SII and SH type gas hydrates
the molecular models of three typical gas hydrates are constructed and optimized. The hydrogen bonds number
hydrogen bonds length
porosity
pore composition
pore size distribution and other structural characteristics of hydrates are determined by structural characterization
and the micro-structure differences of three typical hydrates are compared and analyzed. Based on the hydrate skeleton structure
the adsorption behavior of methane and carbon dioxide is studied by the grand Canonical Monte Carlo method. Combined with the adsorption capacity and adsorption heat
the gas storage characteristics and differences of the three hydrates are clarified. The results show that the hydrogen bonds in SII hydrate are the longest and the most abundant
but the pore connectivity is the worst. High pressure is conducive to increasing the gas storage capacity of hydrate
while low temperature can increase the stability of gas adsorption in hydrate. Although the amount of carbon dioxide storage is smaller than that of methane
the adsorption stability of carbon dioxide is stronger. The adsorption capacity of gas in SII type hydrate is the largest
and the adsorption heat in SI type hydrate is the largest.
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