Molecular Simulation Models of Carbon Dioxide Intercalation in Hydrated Sodium Montmorillonite

Technical Report · Tue Nov 22 04:00:00 EST 2016

DOI:https://doi.org/10.2172/1340995· OSTI ID:1340995

Myshakin, Evgeniy ^[1]; Saidi, Wissam ^[2]; Romanov, Vyacheslav ^[1]; Cygan, Randall ^[3]; Jordan, Kenneth ^[1]; Guthrie, George ^[4]

---

1. National Energy Technology Lab. (NETL), Pittsburgh, PA, (United States)
2. Univ. of Pittsburgh, PA (United States)
3. Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
4. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

In this study, classical molecular dynamics simulations and density functional theory (DFT)-based molecular dynamics are used to elucidate the process of CO₂ intercalation into hydrated Na-montmorillonite at P-T conditions relevant to geological formations suitable for CO₂ storage. Of particular interest are the structural and transport properties of interlayer species after CO₂ intercalation. The conducted simulations allowed the research team to quantify expansion/contraction of smectite as a function of CO₂ and H₂O compositions. The resulting swelling curves can be used to gauge the amount of stored CO₂, compare it to the experiment, and estimate changes in geomechanical properties of the storage formation. The obtained results showed that the infrared signal of the asymmetric stretch vibration of CO₂ molecule is extremely sensitive to the solvent environment. The extent of the frequency shift relative to the gas-phase value can be used to probe hydration level in the interlayer with intercalated CO₂. Interaction of supercritical CO₂ with brine in deep geological formations promotes an increase of hydrophobicity of clay surfaces. As a result of wettability alteration, estimated diffusion constants of CO₂ and H₂O increase with the increased CO₂ load; this can contribute to faster migration of CO₂ throughout the formation.

• Research Organization: National Energy Technology Lab. (NETL), Pittsburgh, PA, (United States)
• Sponsoring Organization: USDOE Office of Fossil Energy (FE)
• OSTI ID: 1340995
• Report Number(s): NETL--TRS-11-2016
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY