Thermodynamic representation of phase equilibria of mixed‐solvent electrolyte systems

Abstract

lates the vapor-liquid equilibrium and liquid-liquid equilibrium of mixedsolvent electrolyte systems over the entire range of temperature and concentrations.Correlation of experimental data for 47 single-solvent electrolyte systems and 33 mixed-solvent electrolyte systems demonstrates that the electrolyte NRTL model gives excellent representation of vapor-liquid equilibrium and liquid-liquid equilibrium of mixed-sol-vent electrolyte systems. Average errors of AP = 1 kPa, AT = 0.1 K, Ay = 0.01 in correlating vapor-liquid equilibrium data at atmospheric conditions, and Ax = 0.01 in correlating liquid-liquid equilibrium data are typical. Previous MethodsIn the late 1960's and the 1970's, several semiempirical models for representing the excess Gibbs energy of nonelectrolyte liquid solutions were developed with the local composition concept. Examples are the Wilson (1964) model, the NRTL model (Renon and Prausnitz, 1968), and the UNIQUAC model (Abrams and Prausnitz, 1975). These models are able to represent, with a reasonable number of binary adjustable parameters, the phase equilibrium of highly nonideal nonelectrolyte systems. Parameter RequirementsThe model binary adjustable parameters are associated with the solvent-solvent pairs, solvent-salt pairs, and salt-salt pairs.

Efficiency Improvement of CO2 Capture

“…For such system Chen et al extended the local composition model NRTL by Renon and Prausnitz [32] by supplementing the model by including the correction of long range forces caused by the presence of ions [8]. The model was further developed by Mock by including the Born correction, which takes the change of the dielectric constants into account on the short range interactions [23]. This is today the ENRTL (electrolyte non-random two-liquid) thermodynamic model.…”

Experimental Measurements and Thermodynamic Modelling of Carbon Dioxide Capture with use of 2-(Ethylamino) Ethanol

“…The non-randomness factor (α) for water -ion par and for molecule -molecule interactions was fixed at 0.2, as recommended by Chen and Evans [25], and as proposed by Mock et al [26] it was kept at value of 0.1 for alkanolamine -ion pair and acid gas -ion pair.…”

“…Moreover, because the experimental VLE data do not include in situ analysis of the VLE's composition, only the molecule-molecule binary interaction parameters were determined. Following the literature [14,25,26] all water -ion pair, and ion pair-water binary parameters were kept at default values (8 and -4). In addition, all other binary parameters (alkanolamine -ion pair; ion pair -alkanolamine; acid gas -ion pair; and ion pair -acid gas) were kept at values of 15 and -8.…”

Influence of MEA and piperazine additives on the desulfurization ability of MDEA aqueous for natural gas purification

“…The electrolyte-NRTL equation [25], which is composed of three contributions of excess Gibbs free energy counted by the Pitzer long-range interaction (PDH), corrected Born term (Born) and short-range solvation effect (NTRL), is used to calculate the activity coefficient of liquid phase The dielectric constant of PZ is calculated as the method described in reference 29 components. For similar weak electrolyte solutions, this model had been widely used to correlate the gas-liquid equilibrium in literatures [16,22,[26][27][28].…”