Thermodynamic Studies of CO2 + TBAB + Water System: Experimental Measurements and Correlations

Abstract

Thermodynamic properties of TBAB + CO2 + water system are important for using TBAB + CO2 semiclathrate hydrates in some promising hydrate-based techniques. This work is an experimental and modeling study of two fundamental properties in vapor–liquid phase equilibrium of TBAB + CO2 + water, that is, CO2 solubility in TBAB solution and density of CO2-saturated TBAB solution. With the use of a PVT system, CO2 solubility was measured; thus, Henry’s constant was obtained at temperatures from 288.1 K to 303.1 K and TBAB mass fraction from 0.10 to 0.40. Our results showed that CO2 is either salted-in or salted-out by the presence of TBAB, depending upon the temperature and TBAB concentration. For the density, we present experimental data for TBAB + water system at T = 283.15 K to 303.15 K with pressures up to 5 MPa. The density of CO2-saturated TBAB aqueous solution was calculated with the help of Duan’s model, which takes into account the effect of pressure and temperature to calculate the apparent molar volume...