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

Abstract

Monoethylene glycol (MEG) is used to prevent hydrate formation in subsea pipelines of natural gas production. MEG is recovered at an offshore regeneration unit. Sodium chloride is the predominant salt in the water−MEG streams. Thus, knowledge of NaCl solubilities in the process conditions is relevant for the design and operation of a MEG regeneration unit. Six isotherms of NaCl solubility were measured (76 data points) from T = (293.15 to 403.15) K in the whole solvent concentration range. The analytical method for salt solubility was based on the reproducibility of the concentration of two successive samples. Density measurements were accurately applied for these analyses. The temperature dependence on NaCl solubility is relatively weak. A reverse behavior with increasing temperature was observed for MEG contents higher than 90 wt %. Salt solubilities were successfully correlated with Redlich−Kister expansion (AADw NaCl = 0.0006 and Δw NaCl = 0.47%). Electrical conductivity of NaClsaturated solutions were measured (44 data points) at T = (293.15 to 363.15) K and correlated with a semiempirical model. A large difference in electrical conductivity for the two solvents was observed. The correlation adequately represented the data set (AADκ = 5.67 mS•cm −1 and Δκ = 5.94%). NaCl solubilities and electrical conductivities were accurately determined and are useful for the MEG regeneration process.

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

“…Islands of higher composition deviations can be observed around w MEG ′ = 0.9. It is noteworthy that these regions overlap the zone of NaCl solubility inversion with temperature, as previously reported by Monteiro et al Furthermore, significant differences between the composition deviations for these three isotherms were not identified.…”

“…For these cases, samples of the liquid phase were retrieved to determine NaCl solubility through density measurements. 28 High sensitivity of the electrical conductivity measurements with respect to the electrolyte concentration and temperature is observed. Figure 2 shows a comparison of the electrical conductivity measurements presented in this work and values reported in the literature for both water + NaCl and MEG + NaCl mixtures.…”

“…It is noteworthy that measurements of electrical conductivity at salt saturation were only studied for the binary systems water + NaCl and MEG + NaCl. For these cases, samples of the liquid phase were retrieved to determine NaCl solubility through density measurements …”

Thermodynamics and Solubility of Electrolytes in Mixed Solvent Systems at High Temperatures

“…(c) NaCl in 0.499 ( w / w ) MEG: black open circles, Djamali et al. ; black open circles, Monterio et al …”

“…(a) NaCl in 0.249 (w/w) CH 3 OH (black) and KCl in 0.2 (w/w) CH 3 OH (blue): black open circles, Djamali et al; 11,12 black and blue open squares, Pinho and Macedo; 31 black and blue solid squares, Li et al 32 (b) NaCl in 0.2498 (w/w) MEG (black) and 0.2 (w/w) MEG (blue): black open circles, Djamali et al; 12 black open diamonds, Masoudi et al; 33 black crosses, Baldwin; 34 blue open triangles, Li et al; 32 solid blue diamonds, Zhou. 35 (c) NaCl in 0.499 (w/w) MEG: black open circles, Djamali et al; 12 black open circles, Monterio et al36…”