Solid-Liquid Equilibrium in Water – Glycols Systems: Measurements and Modelling

Glycols are widely used in the oil and gas industry. Monoethylene glycol (MEG) is often used to avoid hydrate formation and in many new developments, MEG is the preferred hydrate inhibitor over methanol. Another application where glycols are of importance is during the drying of natural gases. In this communication, we report new experimental solid-liquid equilibrium data for the monoethylene glycol (MEG) – water, propylene glycol (PG), diethyelene glycol (DEG) – water and triethylene (TEG) –water systems at temperatures down to -60°C. These new data were used to adjust a thermodynamic model in which the Cubic-Plus-Association equation of state is employed to model the phase equilibria. The new model has been tested with independent hydrate phase equilibrium data.