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Title: Liquid-vapor partitioning of NaCl(aq) from concentrated brines at temperatures to 350{degrees}C

Abstract

Compositions of coexisting liquid and vapor phases have been determined at temperatures from 250 to 350°C for brines containing NaCl and either HCI or NaOH by direct sampling of both phases from a static phase-equilibration apparatus. In these experiments, NaCl concentrations in the liquid phase ranged to 6.5 mol-kg{sup -1}, with corresponding vapor-phase NaCl concentrations varying strongly with temperature and brine composition. Acid or base was added to the brines to suppress unknown contributions of NaCl(aq) hydrolysis products to the observed volatilities. Thermodynamic partitioning constants for NaCl have been determined from the observed compositions of the coexisting phases combined with the known activity coefficients of NaCl(aq) in the liquid phase. An apparent dependence of the values of these partitioning constants on brine concentration is explained by considering the effect of decreasing pressure on the density of the vapor phase. Concentrations of HCI and NaCl in steam produced from various natural brines may be calculated as hnctions of temperature and brine composition based on these new results coupled with our previous determinations of the partitioning constants for HCl(aq). Application of these results to The Geysers will be discussed in terms of the composition of postulated brines which could be in equilibriummore » with observed steam compositions at various temperatures.« less

Authors:
; ;
Publication Date:
Research Org.:
Chemical and Analytical Sciences Division, Oak Ridge national Laboratory, Oak Ridge, 37831
Sponsoring Org.:
USDOE
OSTI Identifier:
889220
Report Number(s):
SGP-TR-147-35
DOE Contract Number:
AC05-84OR21400
Resource Type:
Conference
Resource Relation:
Conference: Proceedings, nineteenth workshop on geothermal reservoir engineering, Stanford University, Stanford, CA, January 18-20, 1994
Country of Publication:
United States
Language:
English
Subject:
Geothermal Legacy

Citation Formats

Simonson, J.M., Palmer, Donald A., and Carter, R.W. Liquid-vapor partitioning of NaCl(aq) from concentrated brines at temperatures to 350{degrees}C. United States: N. p., 1994. Web.
Simonson, J.M., Palmer, Donald A., & Carter, R.W. Liquid-vapor partitioning of NaCl(aq) from concentrated brines at temperatures to 350{degrees}C. United States.
Simonson, J.M., Palmer, Donald A., and Carter, R.W. 1994. "Liquid-vapor partitioning of NaCl(aq) from concentrated brines at temperatures to 350{degrees}C". United States. doi:. https://www.osti.gov/servlets/purl/889220.
@article{osti_889220,
title = {Liquid-vapor partitioning of NaCl(aq) from concentrated brines at temperatures to 350{degrees}C},
author = {Simonson, J.M. and Palmer, Donald A. and Carter, R.W.},
abstractNote = {Compositions of coexisting liquid and vapor phases have been determined at temperatures from 250 to 350°C for brines containing NaCl and either HCI or NaOH by direct sampling of both phases from a static phase-equilibration apparatus. In these experiments, NaCl concentrations in the liquid phase ranged to 6.5 mol-kg{sup -1}, with corresponding vapor-phase NaCl concentrations varying strongly with temperature and brine composition. Acid or base was added to the brines to suppress unknown contributions of NaCl(aq) hydrolysis products to the observed volatilities. Thermodynamic partitioning constants for NaCl have been determined from the observed compositions of the coexisting phases combined with the known activity coefficients of NaCl(aq) in the liquid phase. An apparent dependence of the values of these partitioning constants on brine concentration is explained by considering the effect of decreasing pressure on the density of the vapor phase. Concentrations of HCI and NaCl in steam produced from various natural brines may be calculated as hnctions of temperature and brine composition based on these new results coupled with our previous determinations of the partitioning constants for HCl(aq). Application of these results to The Geysers will be discussed in terms of the composition of postulated brines which could be in equilibrium with observed steam compositions at various temperatures.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = 1994,
month = 1
}

Conference:
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  • Compositions of coexisting liquid and vapor phases have been determined at temperatures from 250 to 350{degree}C for brines containing NaCl and either HCl or NaOH by direct sampling of both phases from a static phase-equilibration apparatus. Thermodynamic partitioning constants for NaCl have been determined from the observed compositions of the coexisting phases combined with the known activity coefficients of NaCl(aq) in the liquid phase. An apparent dependence of the values of these partitioning constants on brine concentration is explained by considering the effect of decreasing pressure on the density of the vapor phase. Concentrations of HCl and NaCl in steammore » produced from various natural brines may be calculated as functions of temperature and brine composition based on these new results coupled with our previous determinations of the partitioning constants for HCl(aq). Application of these results to The Geysers will be discussed in terms of the composition of postulated brines which could be in equilibrium with observed steam compositions at various temperatures.« less
  • Oxygen and hydrogen isotope partitioning between liquid water and water vapor has been precisely determined by means of direct mass-spectrometric measurements of isotopic abundances of the two phases from room temperature to 350{degrees}C. Measurable changes in the liquid-vapor partitioning were observed upon the addition of salts (NaCl, KCl, MgCl{sub 2}, CaCl{sub 2}, Na{sub 2}SO{sub 4}, and MgSO{sub 4}) to the system. The results of isotope partitioning for the isotopic mixtures and the literature data of vapor pressure measurements of separate isotopic waters agree well for pure water, but show notable discrepancy for salt solutions.
  • Oxygen and hydrogen isotope fractionation factors ({alpha}{sub {ell}-v}{sup O} and {alpha}{sub {ell}-v}{sup D}) between liquid water and water vapor have been calculated from vapor pressure ratio measurements and equations of state over the temperature range of 0 to 370{degree}C. These data are compared to the liquid-vapor fractionation factors determined by direct mass spectral measurements. The values for {alpha}{sub {ell}-v}{sup D} derived from the vapor pressure ratios are in close agreement with the experimental mass spectral measurements from 0 to 300{degree}C when fugacity coefficient and molar volume corrections are used. Deviations from the direct measurements above 0 to 300{degree}C are duemore » to inadequacies in either (1) the magnitude of the molar volume correction for D{sub 2}O near the critical point, (2) the assumption of ideal mixing of the isotopic gases and liquids, and/or (3) the selection of 1.91 as the disproportionation factor for the formation of HDO. On the other hand, the {alpha}{sub {ell}-v}{sup O} values derived form vapor pressure data (no fugacity or molar volume corrections) agree closely with low-temperature direct measurement data, pass through some of Bottinga's (1968) high temperature results, and extrapolate smoothly to {alpha}{sub {ell}-v}{sup O} = 0 at the critical temperature as is required by thermodynamics. This behavior coupled with the fact that Bottinga's (1968) oxygen isotope results exhibit a large scatter, indicated that liquid-vapor oxygen isotope fractionation factors based on vapor pressure measurements should be applied to high-temperature geothermal systems rather than the direct mass spectral data. 15 refs., 2 figs., 1 tab.« less
  • A series of vapor-liquid water equilibration experiments were carried out in order to determine the effects of dissolved salts (NaCl, KCl, MgCl{sub 2}, CaCl{sub 2}, MgSO{sub 4}, Na{sub 2}SO{sub 4}, and their mixtures) on oxygen and hydrogen isotope activity ratios in brines at 50--100{degrees}C. NaCl, KCl and Na{sub 2}SO{sub 4} have little or no effect on oxygen isotope activity ratios. However, oxygen isotope activity ratios in CaCl{sub 2}, MgCl{sub 2}, and MgSO{sub 4} solutions are significantly lower than their concentration ratios. In all of the salt solutions studied, hydrogen isotope activity ratios are appreciably higher than their concentration ratios. Themore » isotope effects are all linear with the molalities of the solutions. Mixed salt solutions, including those mimicking natural brines, exhibit the isotope effects additive of those of individual salts. The isotope salt effects observed in this study have profound implications to isotope geochemistry.« less
  • A series of vapor-liquid water equilibration experiments were carried out in order to determine the effects of dissolved salts (NaCl, KCl, MgCl{sub 2}, CaCl{sub 2}, MgSO{sub 4}, Na{sub 2}SO{sub 4}, and their mixtures) on oxygen and hydrogen isotope activity ratios in brines at 50--100{degrees}C. NaCl, KCl and Na{sub 2}SO{sub 4} have little or no effect on oxygen isotope activity ratios. However, oxygen isotope activity ratios in CaCl{sub 2}, MgCl{sub 2}, and MgSO{sub 4} solutions are significantly lower than their concentration ratios. In all of the salt solutions studied, hydrogen isotope activity ratios are appreciably higher than their concentration ratios. Themore » isotope effects are all linear with the molalities of the solutions. Mixed salt solutions, including those mimicking natural brines, exhibit the isotope effects additive of those of individual salts. The isotope salt effects observed in this study have profound implications to isotope geochemistry.« less