Study on the effect of TBAB and THF on the hydrate dissociation conditions for H2O + CO2 + C6H14+C14H30 systems

In this study, hydrate dissociation conditions for the carbon dioxide + hexane + tetradecane + water systems were experimentally determined with or without Tetra -n-Butyl Ammonium (TBAB) or Tetrahydrofuran (THF), two water-soluble thermodynamic hydrate promoters. The equilibrium conditions were measured using the pressure-search method at constant volume in the temperature range from 274.8 to 291.5 K and pressure range from 1.45 to 3.97 MPa at (0, 0.1, 0.2 and 0.3) mass fraction of TBAB or THF in liquid solution. In order to verify the viability of the method used, the three-phase hydrate equilibria (H -L-w -V) of binary (CO2 + H2O) and ternary (CO2 + H2O + THF) systems were also measured and compared with the literature. Experimental measurements show that the addition of TBAB or THF expands the hydrate stability region significantly to a higher temperature at a specified pressure. The combined standard uncertainties were determined for temperature and pressure and are 0.19 K and 0.07 MPa, respectively. The relative standard uncertainty in composition was estimated to be 0.0013.