Details

Autor(en) / Beteiligte

• Sun, Rui
• Lai, Shaocong
• Dubessy, Jean

Titel

Calculation of vaporaliquid equilibrium and PVTx properties of geological fluid system with SAFT-LJ EOS including multi-polar contribution. Part III. Extension to wateralight hydrocarbons systems

Ist Teil von

• Geochimica et cosmochimica acta, 2014-01, Vol.125, p.504-518

Erscheinungsjahr

2014

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• The SAFT-LJ EOS improved by Sun and Dubessy (2010, 2012) is extended to wateralight hydrocarbon systems. Light hydrocarbons (including CH4, C2H6, C3H8 and nC4H10) are modeled as chain molecules without multi-polar moments. The contributions of the shape of molecules and main intermolecular interactions existing in wateralight hydrocarbon systems (including repulsive and attractive forces between Lennard-Jones segments, the hydrogen-bonding force and the multi-polar interaction between water molecules) to the residual Helmholtz energy were accounted for by this EOS. The adjustable parameters for the interactions of H2OaCH4, H2OaC2H6, H2OaC3H8, and H2OanC4H10 pairs were evaluated from mutual solubility data of binary waterahydrocarbon systems at vaporaliquid equilibria. Comparison with the experimental data shows this SAFT-LJ EOS can represent well vaporaliquid (and liquid-liquid) equilibria of binary wateralight hydrocarbon systems over a wide PaT range. The accuracy of this EOS for mutual solubilities of methane, ethane, propane and water is within the experimental uncertainty generally. Moreover, the model is able to accurately predict the vaporaliquid equilibria and PVTx properties of multi-component systems composed of water, light hydrocarbon as well as CO2. As we know, this EOS is the first one allowing quantitative calculation of the mutual solubilities of water and light hydrocarbons over a wide PaT range among SAFT-type EOSs. This work indicates that the molecular-based EOS combined with conventional mixing rule can well describe the thermodynamic behavior of highly non-ideal systems such as wateralight hydrocarbons mixtures except in the critical region for which long range density fluctuations cannot be taken into account by this analytical model.