It has been known that CH4 from deep sea gas hydrate deposit can be replaced by CO2, i.e. both the exploitation of CH4 and storage of CO2 can be achieved simultaneously. To explore the potential application of CO2 hydrate, it is necessary to have better understanding on the kinetic and thermodynamic aspect of CO2 hydrate with marine environmental factors such as types of sediment organic matters and soil minerals. In this study, we investigated an enhanced CO2 hydrate formation in organo-mineral complex suspensions and performed molecular dynamics (MD) simulation to fully understand the CO2 hydrate nucleation by using LAMMPS package. Hydrate formation kinetic were monitored in the organo-mineral complex suspensions containing various organic matters and soil minerals. Organo-mineral complex (Na-Montmorillonite (Na-MMT) and glycine) suspension showed much more favorable hydrate formation kinetics (2-6 min) than pure water control (48-80 min). MD simulation result with Na-MMT and glycine showed that CO2 hydrate nucleation can occur by the interaction between soil mineral and organic matters. Positively charged NH3+ side of glycine made strong hydrogen bonding with negatively charged silicate atoms of Na-MMT. This organo-mineral complex serves as a nucleation site for the CO2 hydrate formation. The hydrogen atoms of water molecules were rearranged towards COO- side of glycine, while oxygen atom of CO2 molecule was driven by NH3+ side of glycine to make an intermediate hydrate structure and this one plays a key role in complete hydrate formation as nucleation seeds. This fundamental knowledge could be applied to in-situ swapping technology to recover CH4 from deep sea gas hydrate deposits and sequester the CO2 to CH4 hydrate layer.

Effects of organo-mineral complex on CO<sub>2</sub> hydrate formation kinetic

244th National Meeting (2012)

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Effects of organo-mineral complex on CO2 hydrate formation kinetic

Effects of organo-mineral complex on CO₂ hydrate formation kinetic