Journal of Chemical and Engineering Data, Vol.62, No.10, 3445-3451, 2017
Phase Behavior of Carbon Dioxide Hydrates: A Comparison of Inhibition Between Sodium Chloride and Ethanol
In view of the possibilities for hydrate formation caused by carbon dioxide rich fluids in the production lines of the Brazilian Pre-Salt fields, this study focus on experimental measurements to obtain fundamental insight into the phase behavior of carbon dioxide hydrate forming systems. This work considers the influence of sodium chloride and ethanol, hydrate inhibitors, on this phase behavior and its implications to practical applications. In addition, the inhibiting effect of ethanol on hydrates was compared with that of sodium chloride at the same mass fractions. The carbon dioxide hydrate phase behavior was measured using a high-pressure equilibrium cell in the temperature range of 272-279 K and pressures up to 3.9 MPa. Experimental measurements using the isothermal method were performed by monitoring the pressure response of the system with volume changes. Enthalpies of dissociation for carbon dioxide hydrates were estimated from the measured three-phase (L-w-H-V)data by applying the Clausius-Clapeyron equation. Results showed that, at the same mass fraction of the inhibitor and high-pressure conditions, the sodium chloride exhibited a superior inhibiting effect compared to that of the ethanol.