Effect of 1-Propanol and TBAB on Gas Hydrates Dissociation Conditions for CO₂ + Hexane + Water Systems

Hydrate equilibrium conditions of carbon dioxide in the presence of hexane in aqueous solutions of 1-propanol/tetra-n-butyl ammonium bromide (TBAB) have been studied in this Article. The hydrate dissociation conditions of water + hexane + CO₂ + 1-propanol and water + hexane + CO₂ + TBAB systems have been measured in 271.21-290.77 K and 1.21-3.57 MPa temperature and pressure ranges, respectively, using an isochoric pressure-search method (synthetic nonvisual method). The mass fractions of hexane were 0.05, 0.09, and 0.30, while mass fractions of 1-propanol were 0.10 and 0.30 and for TBAB were 0.09 and 0.19. The hydrate dissociation conditions for CO₂ + H₂O system are compared with the experimental data reported in the literature. Good agreement between the data indicates the viability of the experimental technique reported in this study. The experimental uncertainties were determined for temperature and pressure as combined uncertainties and are 0.120 K and 0.03 MPa, respectively. The relative standard uncertainty in composition was estimated to be 0.0013 in mass fraction. Based on our experimental data, 1-propanol acts as thermodynamic inhibitor for CO₂ + hexane hydrate; on the contrary, TBAB proved to act strongly as a thermodynamic promoter.