A Comparative Study on Four Thermodynamic Frameworks of the Clathrate Phase: Predicting the Three-Phase Hydrate Equilibrium

This work focuses on critically analyzing the four groundbreaking thermodynamic formulations of gas hydrates, namely, the van der Waals–Platteeuw, Chen–Guo, Klauda–Sandler, and Dongre–Jana models, which provide fundamental insights into clathrate thermophysics by depicting the three (hydrate–liquid–vapor) phase equilibria. At first, a holistic view of the primal versions of all the thermodynamic models is presented. Subsequently, a modification to evaluate the chemical potential of saline water in the liquid phase of the concerned formulations is proposed. Further, an Elitist-nondominated sorting genetic algorithm-based strategy is articulated to estimate the globally optimal parameter sets of the models having more than two parameters. Finally, the models are investigated in terms of their capability to predict clathrate phase equilibrium pressures for a wide variety of systems. It is perceived that the proposed optimization technique significantly improves the prediction performance of the Klauda–Sandler and Chen–Guo models, and the parameter-free formulation of Dongre–Jana predicts hydrate phase equilibria with higher accuracy.