Atomistic molecular dynamics simulations of H2O diffusivity in liquid and supercritical CO2

Molecular dynamics simulations were employed for the calculation of diffusion coefficients of pure CO 2 and of H 2 O in CO 2 over a wide range of temperatures (298.15 K < T < 523.15 K) and pressures (5.0 MPa < P < 100.0 MPa), that are of interest to CO 2 capture-and-sequestration process...

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Published inMolecular physics Vol. 113; no. 17-18; pp. 2805 - 2814
Main Authors Moultos, Othonas A., Orozco, Gustavo A., Tsimpanogiannis, Ioannis N., Panagiotopoulos, Athanassios Z., Economou, Ioannis G.
Format Journal Article
LanguageEnglish
Published Abingdon Taylor & Francis 17.09.2015
Taylor & Francis Ltd
Subjects
diffusion coefficients
force-fields
molecular dynamics simulation
Simulation
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Summary:Molecular dynamics simulations were employed for the calculation of diffusion coefficients of pure CO 2 and of H 2 O in CO 2 over a wide range of temperatures (298.15 K < T < 523.15 K) and pressures (5.0 MPa < P < 100.0 MPa), that are of interest to CO 2 capture-and-sequestration processes. Various combinations of existing fixed-point-charge force-fields for H 2 O (TIP4P/2005 and Exponential-6) and CO 2 (elementary physical model 2 [EPM2], transferable potentials for phase equilibria [TraPPE], and Exponential-6) were tested. All force-field combinations qualitatively reproduce the trends of the experimental data for infinitely diluted H 2 O in CO 2 ; however, TIP4P/2005-EPM2, TIP4P/2005-TraPPE and Exponential-6-Exponential-6 were found to be the most consistent. Additionally, for H 2 O compositions ranging from infinite dilution to , the Maxwell-Stefan diffusion coefficient is shown to have a weak non-linear composition dependence.
ISSN:0026-8976
1362-3028
DOI:10.1080/00268976.2015.1023224