Density and Electrical Conductivity for Aqueous Mixtures of Monoethylene Glycol and Sodium Chloride: Experimental Data and Data-Driven Modeling for Composition Determination

Abstract

Monoethylene glycol (MEG) is a gas hydrate inhibitor widely applied for natural gas flow assurance. A series of density and electrical conductivity measurements of water + MEG + NaCl mixtures are reported, allowing the supervision of the MEG regeneration unit. Density (509 data points) and electrical conductivity (212 data points) measurements were performed in wide ranges of temperature, T = 278.15–363.15 K, and concentration of solvents and NaCl up to almost saturation. The theory of solutions was applied for density description using excess volume, which was correlated with the Redlich–Kister equation. The resulting absolute and relative mean deviations are 0.00127 g·cm–3 and 0.12%, indicating accurate representation. A semiempirical correlation with 15 adjustable parameters was considered for electrical conductivity of water + MEG + NaCl mixtures. The obtained absolute and relative mean deviations are 1.49 mS·cm–1 and 5.70%. The properties functions presented an approximately orthogonal behavior to each other, allowing the determination of mixture composition from experimental density and electrical conductivity data. The Matlab environment was found to be robust in solving the nonlinear system of two equations with constraints. The proposed methodology was extensively tested, and deviations less than 0.0060 and 0.0011 in solvents and NaCl mass fractions were obtained, respectively, demonstrating the required accuracy for industrial application.

Salt Solubility and Saturated Electrical Conductivity Data for Water + Monoethylene Glycol + NaCl in a Wide Temperature Range

“…The density calibration curves were determined at 298.15, 323.15, and 353.15 K. These calibration curves have been applied to the salt solubility determination at 293.15, 318.15, and 348.15 K. The 5 K difference between the calibration and solubility data curves was applied to avoid salt precipitation inside the density meter. Density experimental values used for the calibration curves were previously reported at 298.15 K by Moura-Neto et al and at 323.15 and 353.15 K by Moura-Neto et al …”

“…The density calibration curves were determined at 298.15, 323.15, and 353.15 K. These calibration curves have been applied to the salt solubility determination at 293.15, 318.15, and 348.15 K. The 5 K difference between the calibration and solubility data curves was applied to avoid salt precipitation inside the density meter. Density experimental values used for the calibration curves were previously reported at 298.15 K by Moura-Neto et al 30 and at 323.15 and 353.15 K by Moura-Neto et al 31 In order to demonstrate the validation of the experimental procedure used, values of the observed salt solubility have been compared to the data sets of Trimble, 12 Baldwin et al, 15 Massoudi et al, 13 and Zeng and Li; 18 As can be observed in Figure 2, experimental measurements present quantitative agreement with the literature. However, the work by Massoudi and co-authors 13 presented relatively high deviation in relation to the other authors.…”

Salt solubility modeling in mixed solvents with a modified Pitzer approach: Application in water + MEG + electrolyte systems

“…In this work, the approach proposed by Lorimer was applied for eight strong electrolytes in water–MEG mixtures. For the calculation of the density of pure water and MEG, and its mixtures, the equations reported by Moura‐Neto et al 20 were applied. Regarding dielectric constants for pure solvents, the equations reported by Åkerlöf 23 were used.…”

“…18,19 The regeneration process consists in removing salts and water by using mainly a vacuum flash separator and a distillation column. Thus, the accurate description of physicochemical properties 20 and phase behavior 21 for such ternary mixtures are of interest to the natural gas industry.…”

Volumetric, Viscometric, and Refractive Index Studies of Drug Nicotinic Acid in Aqueous d-Xylose/l-Arabinose Solutions from 293.15 to 313.15 K: Insights into Solute–Solute and Solute–Solvent Interactions

“…Volumetric analysis is a crucial method of elucidating the physicochemical phenomena of solutes in solution. − Moreover, the viscosity and refractive index of the mixed solution are two other important parameters that can provide valuable information for a better understanding of intermolecular interactions. − It is well known that most biochemical processes occur in aqueous media. Therefore, research on the volumetric properties, viscometric properties, and refractive indices of drugs in aqueous media is helpful for deepening the understanding of drug molecular interactions, which contributes significantly to advancements in the fields of pharmacy and pharmaceutical chemistry. − However, the drug–solvent interactions that can elucidate the solvation behavior of drugs in vivo are difficult to investigate directly because of the presence of various cosolutes, such as carbohydrates, amino acids, salts, proteins, and so forth in biosystems.…”