Vapor-Liquid Equilibrium Measurements and Cubic-Plus-Association Modeling of Triethylene Glycol Systems

Due to the low vapor pressure of triethylene glycol, there is limited vapor-liquid equilibria data involving this component at high pressure. Aiming to expand this experimental database, new vapor-liquid equilibria data points were measured for the systems: triethylene glycol (1) + methane (2), triethylene glycol (1) + ethane (2), triethylene glycol (1) + ethane (2) + water (3), and triethylene glycol (1) + gas mixture (2). The experimental ranges were within the relevant process conditions for the natural gas dehydration, with T = (293.15, 333.15) K, and P = (3.0, 18.0) MPa. The new data include both gas and liquid phase compositions with relative experimental uncertainties (u) below 0.17. Furthermore, the Cubic-Plus-Association (CPA) using the 4C association scheme for triethylene glycol (TEG) and only one interaction parameter per binary has provided a qualitative description of the newly measured data, with average absolute relative deviation (AARD) ranging between 3% and 54%.