Interfacial properties of methane/aqueous VC-713 solution under hydrate formation conditions.

The interfacial tensions between methane and aqueous solutions of different contents of VC-713 (a terpolymer of N-vinylpyrrolidone, N-vinylcaprolactam, and dimethylamino-ethyl-methacrylate) were measured at different temperatures and pressures in the hydrate formation region. The surface adsorption free energies of methane were calculated accordingly in order to investigate the effect of this kinetic inhibitor on the nucleation of hydrate. The results show that the presence of VC-713 lowers the interfacial tension, increasing the concentration of methane on the surface of the aqueous phase, and thus promotes nucleation of hydrate at the gas/liquid interface.

Solubility measurement of methane in aqueous solution of sodium dodecyl sulfate at ambient temperature and near hydrate conditions.

Solubility data of methane in aqueous solutions of sodium dodecyl sulfate (SDS) with different concentrations were measured at ambient temperature and near hydrate conditions. The critical micelle concentration (CMC) and the number of methane molecules dissolved in each micelle of the methane + water + SDS system were calculated and compared with those of the ethylene + water + SDS system. The results demonstrated that the micelles could be formed in the SDS concentration range where an efficient promotion effect on hydrate formation was previously reported; the micelle solubilization to methane molecules was remarkable near hydrate conditions, and the ethylene molecules could be solubilized in micelles in preference to methane molecules.

Solubility of ethylene in aqueous solution of sodium dodecyl sulfate at ambient temperature and near the hydrate formation region.

The solubility of ethylene in aqueous solutions of sodium dodecyl sulfate (SDS) at different concentrations was measured at temperature 298.2 K and near the hydrate formation region. The effect of SDS on the gas solubility was studied and the solubilities of ethylene in a single micelle under different conditions were evaluated.

Interfacial tension of ethylene and aqueous solution of sodium dodecyl sulfate (SDS) in or near hydrate formation region.

The interfacial tensions between ethylene and an aqueous solution of SDS were measured using the pendant-drop method at 274.2 and 278.2 K and in the pressure range from 0.