CO2 hydrate formation and dissociation is crucial for hydrate-based CO2 capture and storage. Experimental and calculated phase equilibrium conditions of carbon dioxide (CO2) hydrate in porous medium were investigated in this study. Glass beads were used to form the porous medium. The experimental data were generated using a graphical method. The results indicated the decrease of pore size resul...

[1] The interaction among water molecules, guest gas molecules, salts, and mineral particles determines the nucleation and growth behavior of gas hydrates in natural sediments. Hydrate of tetrahydrofuran (THF) has long been used for laboratory studies of gas hydrate-bearing sediments to provide close control on hydrate concentrations and to overcome the long formation history of methane hydrate...

Large reservoirs of methane hydrate exist in arctic permafrost and seafloor sediments. The physical properties of the permafrost and marine sediments are believed to affect hydrate stability. In 2004, Uchida et al. investigated the decomposition of methane hydrates formed in porous media using a laboratory pressure facility. They observed a shift of the hydrate stability curve and concluded tha...

The crystal structures of Na2SeO4·1.5H2O (sodium selenate sesquihydrate) and Na2SeO4·10H2O (sodium selenate deca-hydrate) are isotypic with those of Na2CrO4·1.5H2O and Na2 XSeO4·10H2O (X = S, Cr), respectively. The asymmetric unit of the sesquihydrate contains two Na(+) cations, one SeO4 tetra-hedron and one and a half water mol-ecules, the other half being generated by twofold rotation symmetr...

Dissociation processes of methane hydrate synthesized with glass beads were investigated using powder X-ray diffraction and calorimetry. Methane hydrate formed with coarse glass beads dissociated quickly at 150-200 K; in this temperature range methane hydrate dissociates at atmospheric pressure. In contrast, methane hydrate formed with glass beads less than a few microns in size showed very hig...

The kinetics of film growth of hydrates of methane, ethane, and methane-ethane mixtures were studied by exposing a single gas bubble to water. The morphologies, lateral growth rates, and thicknesses of the hydrate films were measured for various gas compositions and degrees of subcooling. A variety of hydrate film textures was revealed. The kinetics of two-dimensional film growth was inferred f...

An understanding of the physical properties of hydrate-bearing sediments is important for interpretation of geophysical data collected in field settings, borehole and slope stability analyses, and reservoir simulation and production models. Yet current knowledge of geophysical and geotechnical properties of hydratebearing sediments is still largely derived from laboratory experiments conducted ...

One of the options suggested for methane recovery from natural gas hydrates is molecular replacement of methane by suitable guests like CO2 and N2. This approach has been found to be feasible through many experimental and molecular dynamics simulation studies. However, the long term stability of the resultant hydrate needs to be evaluated; the decomposition rate of these hydrates is expected to...