The knowledge of the phase envelope for hydrocarbon mixtures and especially the hydrocarbon dew point is essential for the oil & gas industry, both for natural gas processing and for its transportation. Correct prediction of the natural gas phase equilibrium curves is necessary for deciding the operating conditions for separators so that the gas products meet certain specifications. Furthermore, accurate dew points are also needed in order to design a safe and effective network of transportation pipelines for natural gas. Hydrocarbon condensation in the pipelines increases the pressure drop and introduces operational problems resulting from the two-phase flow in pipelines designed for single-phase transportation. TTPL has developed a thermodynamic model, the so-called UMR-PRU, which gives very good predictions of the phase equilibrium for a variety of mixtures. Especially for natural gas mixtures UMR-PRU is capable of predicting the dew point with much better accuracy than the thermodynamic models commonly employed in the commercial process simulators. The extension of UMR-PRU for natural gas mixtures was realized in the framework of a research project assigned by Statoil SA, Norway.

Selected publications:

• Koulocheris V., Louli V., Panteli E., Skouras S., Voutsas E., Modelling of elemental mercury solubility in natural gas components, Fuel, 233, 2018, 558-564
• Novak N., Louli V., Skouras S., Voutsas E., Prediction of dew points and liquid dropouts of gas condensate mixtures, Fluid Phase Equilibria 457, 2018, 62-73
• Louli, V., Pappa G., Boukouvalas, C., Skouras S., Solbraa, E., Christensen K.O., Voutsas E., Measurement and prediction of dew point curves of natural gas mixtures, Fluid Phase Equilibria 334, 2012, 1-9