Optimization of determination of CO2 gas hydrates surface tension in the presence of non-ionic surfactants and TBAC

Abstract

The gas hydrates formation, in spite of its disadvantages, has some advantages such as separating, transferring and storing gas. Therefore, determining the appropriate promoters for the gas hydrates’ formation is as important as selecting an appropriate inhibitor. One of the effective promoters is Tetra-N-Butyl ammonium chloride (TBAC). Due to TBAC'snon-destructive environmental effects and its extraordinary effect on the thermodynamics of gas hydrates, this salt is one of the most widely used promoters. TBAC was discussed in the context of hydrate structure formation and Alkyl Poly Glucoside (APG) as a nonionic surfactant due to biodegradability, emulsifiers, and reasonable prices. In this study, the surface tension between CO2hydrates was evaluated at constant temperatures and pressures with different concentrations. For this purpose, the classical nucleation theory has been used. The experimental data show that at constant temperature, the induction time was reduced by increasing the TBAC concentration and adding APG. Also, the surface tension value reduced significantly by adding APG, led to an upward trend with increasing temperature. Finally, the surface tension values obtained from the developed method were compared by presented correlations. The results of the developed model are in satisfactory agreement with literature data.