查看文章

Prediction of phase equilibria of semi-clathrate hydrates has been very rarely investigated in the literature. In this work, a thermodynamic model is proposed for representation/prediction of phase equilibria of semi-clathrate hydrates of the CO₂, CH₄, or N₂+tetra-n-butylammonium bromide (TBAB) aqueous solution. For modeling the hydrate phase, the van der Waals–Platteeuw (vdW–P) solid solution theory is used, revised with two modifications for evaluations of Langmuir constants and vapor pressure of water in the empty hydrate lattice, in which these values are supposed to be a function of TBAB concentration in aqueous solution. The Peng–Robinson (PR-EoS) equation of state along with re-tuned parameters of Mathias–Copeman alpha function is applied for calculation of the fugacity of gaseous hydrate former. For determination of the activity coefficient of the non-electrolyte species in the aqueous phase, the …