Modification of Peng Robinson EOS for modelling (vapour+liquid) equilibria with electrolyte solutions

Extension of the electrolyte Trebble–Bishnoi EOS to mixed‐salt systems, and application to vapour liquid and solid (hydrate) vapour liquid equilibrium calculations

“…[3][4][5][6][7][8][9][10][11][12][13] Whereas activity coefficient models are typically derived from Gibbs energy models, equations of state for aqueous electrolyte solutions are typically derived from Helmholtz energy models, which consist of both non-electrolyte and electrolyte contributions. The non-electrolyte term is most commonly modelled by a cubic equation of state [14][15][16][17][18][19][20][21][22][23][24][25][26][27] or by a variant of the Statistical Associating Fluid Theory equation of state. [28][29][30][31][32][33] However, a handful of equations of state have also employed a square well potential, [34,35] a perturbed hard sphere model, [36,37] or a lattice-based term.…”

“…These parameters can be broadly classified as either salt-specific parameters or ion-specific parameters. Equations of state that have salt-specific parameters [15][16][17]20,22,24,26,27,34,35,38] treat the undissociated salt as a single component and do not consider the presence of dissolved anions or cations. In contrast, equations of state that have ion-specific parameters [14,18,[28][29][30][31][32][33]36,37,39] consider the dissolved anions and dissolved cations as separate species, but they do not consider the undissociated salt to be present.…”

“…To date, electrolyte equations of state have been assessed for a variety of phase equilibrium calculations. In single electrolyte systems, it has been shown that water vapour pressures, [28][29][30]37,38] gas solubilities, [14,16,17,20,25,27,30,32,38] salt solubilities, [18,24,31] and gas hydrate equilibrium conditions [16,19,21,23,24,26,33,36,39,40] can be accurately predicted, using a single equation of state for all fluid phases. In contrast, phase equilibrium data for mixed electrolyte systems are relatively scarce, and thus, relatively few attempts have been made at the modelling phase behaviour in aqueous mixed-salt systems.…”

“…Ion-ion electrostatic interaction terms are most commonly represented by either the mean spherical approximation [14,16,[18][19][20][21]32,[34][35][36][37][38] (MSA) or by the Debye-Hückel theory, [17,20,23,[29][30][31] whereas equations of state that include an ion charging term, [14][15][16][19][20][21]27,28,30,32] most often represent it as a Born energy term. [14,15,20,22,24,[30][31][32] Ion-water interactions, on the other hand, have been described by an association term, [14,21,22,[28][29][30][31][32][33] a Margules term, [17,20] or an ion solvation term. [16] Regardless of the exact combination of terms that make up a...…”

Thermodynamic modeling of solid solubility in supercritical carbon dioxide: Comparison between mixing rules

“…The Peng-Robinson equation of state (PR-EOS) is a well-known cubic EOS that gives a good qualitative picture of all types of SCF phase behavior and reasonably it gives good quantitative fits for a wide variety of systems [11,12]. For example, many researchers used the PR-EOS for modeling of vapor liquid equilibrium or solid vapor equilibrium which contains supercritical carbon dioxide [13,14]. Moreover, PR-EOS has also been attempted to model the solubility of polar solutes in supercritical CO 2 in the presence of a polar co-solvent with some degree of success [15,16].…”