Hydrocarbons – water phase equilibria using the CPA equation of state with a group contribution method

Abstract

It is proposed in this paper to extend the original group contribution method PPR78 to systems containing water, by combining it to the Cubic–Plus–Association (CPA) equation of state (EoS). Applying simple geometric combination rules, the binary interaction parameter kij(T) can be calculated from interaction parameters between hydrocarbon groups and water. This model, called the GC–PR–CPA is applied to predict hydrocarbons – water mutual solubilities over a wide temperature and pressure range, depending on available literature data. Group interaction parameters, here CH4, C2H6, CH3, CH2, CH, C, CHaro, CH2,cyclic, CHcyclic/Ccyclic, C2H4, CH2,alkene/CHalkene with H2O have been defined with solubility data. Predictions of the developed model have been validated against independent solubility data as well as water content in hydrocarbon rich phase. Predictions of the new model are in good agreement for light and medium hydrocarbons; however, some deviations are observed for heavier hydrocarbons.

Impact of non-ideality on mixing of hydrocarbons and water at supercritical or near-critical conditions

“…The phase equilibrium water compositions are shown in Figure 1 with experimental measurements from the literature. The water mole fractions of n-decane match well with the measurements, but those of toluene have deviations of ~20% (Note that using a cubic-plus-association EoS [46], which is compatible with PPR78, improves the phase equilibrium calculations). As a group contribution method, PPR78 yields phase equilibrium results with correct trends and tolerable errors.…”

Thermodynamic study of the CO2 – H2O – NaCl system: Measurements of CO2 solubility and modeling of phase equilibria using Soreide and Whitson, electrolyte CPA and SIT models

“…The parameters ( , , , , ) for pure water are obtained by adjusting to vapor pressure and saturated liquid density data correlated by NIST [38]. The water parameters obtained in this work and those obtained previously by Hajiw et al [23] and Wang et al [24,25] are reported in Table 4. As shown in Figure 2, the e-PR-CPA model can accurately describe the pure water VLE data, apart in the near critical region.…”

Predicting phase behavior in aqueous systems without fitting binary parameters I: CP‐PC‐SAFT EOS, aromatic compounds

“…Some of the latter studies have correlated the experimental data by the Cubic equations attached by one 12 and two 11 system-specific, three system-and temperature-specific 18,19 and four systemspecific 20 binary adjustable parameters. In this respect, several recent researches [21][22][23][24][25][26][27][28][29][30] performing a modeling of phase equilibria in the water-aromatic compound systems using various approaches should be acknowledged as well. The last two studies present a significant interest in the context of the current investigation.…”