Molecular simulation of the potential of methane reoccupation during the replacement of methane hydrate by CO(2)

Chun-Yu Geng; Hao Wen; Han Zhou

doi:10.1021/jp811474m

Molecular simulation of the potential of methane reoccupation during the replacement of methane hydrate by CO(2)

J Phys Chem A. 2009 May 7;113(18):5463-9. doi: 10.1021/jp811474m.

Authors

Chun-Yu Geng¹, Hao Wen, Han Zhou

Affiliation

¹ State Key Laboratory of Multi-Phase Complex Systems, Institute of Process Engineering, Chinese Academy of Sciences, No. 1 2nd North Lane, ZhongGuanCun, Beijing 100190, China.

PMID: 19361183
DOI: 10.1021/jp811474m

Abstract

Molecular dynamics simulations and stabilization energy calculations are performed in this work in order to understand the stability of CH(4) hydrate, CO(2) hydrate, and CH(4)-CO(2) mixed hydrate. The model systems of fully occupied type SI CH(4) hydrate, CO(2) hydrate, and CH(4)-CO(2) mixed hydrate are prepared in a simulation box of 2 x 2 x 2 unit cell with periodic boundary conditions. The MD simulation results reveal that the CH(4)-CO(2) mixed hydrate is the most stable one in above three hydrates. The stabilization energy calculations of small and large cavities occupied by CH(4) and CO(2) show that the CO(2) molecule is less suitable for the small cavity because of its larger size compared with the CH(4) molecule but is more suitable for the large cavity. The results in this work can also explain the possibility of CH(4) molecule in reoccupying the small cavity during the replacement of CH(4) hydrate by CO(2), from the hydrate stability point of view.