Hydrate - fluid phase equilibria modeling using PC-SAFT and Peng-Robinson equations of state

In this work, the Perturbed-Chain Statistical Associating Fluid Theory (PC-SAFT) and the Peng-Robinson (PR) cubic equation of state are coupled with the van der Waals-Platteeuw theory in order to calculate the hydrate phase equilibria for different pure gases, including CH4, C2H6, C3H8, iC(4)H(10) CO2, N-2, Ar, O-2 and H2S, as well as representative binary, ternary and quaternary mixtures of these gases. Calculations for three-phase (Hydrate - Liquid water - Vapor; HLwV) equilibria are performed. The optimization of the Kihara epsilon parameter, through a fit to experimental data further improves the accuracy in correlating the hydrate equilibrium pressure for both models. Overall, it is shown that PR is more accurate than PC-SAFT for the prediction of clathrate hydrate equilibrium conditions for the systems considered. (C) 2015 Elsevier B.V. All rights reserved.