A Molecular Dynamics Study on CO$_2$ Diffusion Coefficient in Saline Water Under a Wide Range of Temperatures, Pressures, and Salinity Concentrations: Implications to CO2 Geological Storage (original) (raw)

Carbon dioxide (CO2) sequestration in saline aquifers has been introduced as one of the most practical, longterm, and safe solutions to tackle a growing threat originating from the emission of CO2. Successfully executing and planning the process necessitates a comprehensive understanding of CO2 transport propertiesparticularly the diffusion coefficient, influencing the behavior of CO2 dissolution in water/brine regarding the shape of viscous fingers, the onset of instabilities, etc. In this research, Molecular Dynamics (MD) simulation was employed to compute the CO2 diffusion coefficient in various NaCl saline water concentrations (1-6 mol NaCl/kg water) under the broad spectrum of temperatures (294-423 K) and pressures (10-30 MPa) to acquire a data-set for the CO2 diffusion coefficient in different circumstances. According to the results, the NaCl concentration increase gives rise to a decrease in the CO2 diffusion coefficient, by which the reduction is most notably at higher tempe...