Accurate prediction of clathrate hydrate phase equilibria below 300 K from a simple model

A simple thermodynamic model with only two adjustable parameters has been developed which can accurately correlate hydrate-liquid water-vapor (H-L_W-V) phase equilibrium for single-guest gas hydrates at temperatures below 300 K. The approach combines the van der Waals-Platteeuw theory and the Peng-Robinson equation of state, and provides a unified treatment of the two fluid phases (liquid water and hydrocarbon). The present model compares favorably with other methods in the literature in terms of average absolute percent deviation (AAPD) from available experimental data. We further find that the accuracy of the calculations is insensitive to the solubility of guest molecules in liquid water.