%0 Journal Article %1 Driesner2007a %A Driesner, Thomas %D 2007 %J Geochimica et Cosmochimica Acta %K 2007 NaCl brine correlation enthalpy equation-of-state heat-capacity %N 20 %P 4902 - 4919 %R 10.1016/j.gca.2007.05.026 %T The system H2O-NaCl. Part II: Correlations for molar volume, enthalpy, and isobaric heat capacity from 0 to 1000 °C, 1 to 5000 bar, and 0 to 1 XNaCl %U http://dx.doi.org/10.1016/j.gca.2007.05.026 %V 71 %X A set of correlations for the volumetric properties and enthalpies of phases in the system H2O-NaCl as a function of temperature, pressure, and composition has been developed that yields accurate values from 0 to 1000 °C, 1 to 5000 bar, and 0 to 1 XNaCl. The volumetric properties of all fluid phases from low-density vapor to hydrous salt melts and single-phase binary fluids at high pressures and temperatures, can be described by a simple equationi.e., for a given pressure and composition, the molar volume of the solution is related to the molar volume of pure water at the same pressure by a linear scaling of temperature. The parameters n1 and n2 are simple functions of pressure and composition. This linear relation could be demonstrated for all (P, XNaCl) pairs where accurate volumetric data are available over a sufficiently large temperature interval. Extrapolations over as much as 300 °C predict high temperature data within their experimental uncertainty of 1-2\%. With a simple fit of parameters n1 and n2, the vast majority of several thousand experimental data points from the literature can be reproduced within experimental error, including dilute solutions in the compressible region. Although a strict theoretical foundation is lacking, this behavior can phenomenologically be rationalized as reflecting the relation between the linear to near-linear isochores of binary fluids to those of pure water. Accordingly, small deviations from linearity that amount to 0.1-0.2\% error in molar volume occur only at low temperatures where the pure water isochores behave non-linearly. This effect is accounted for by introducing a deviation function. Given its high accuracy, the formulation for the molar volumes could be integrated along isotherms-isobars to generate data for the specific enthalpy of binary solutions. In order to allow direct computation rather than numerical integration, a correlation scheme was developed that is mathematically similar to that for molar volumes. Specific enthalpies computed from the correlation typically agree within 1-3\% with those obtained from other studies. Similarly, isobaric heat capacities show good agreement with published data except for high salinities at moderate pressures and temperatures.

@article{Driesner2007a, abstract = {A set of correlations for the volumetric properties and enthalpies of phases in the system H2O-NaCl as a function of temperature, pressure, and composition has been developed that yields accurate values from 0 to 1000 °C, 1 to 5000 bar, and 0 to 1 XNaCl. The volumetric properties of all fluid phases from low-density vapor to hydrous salt melts and single-phase binary fluids at high pressures and temperatures, can be described by a simple equationi.e., for a given pressure and composition, the molar volume of the solution is related to the molar volume of pure water at the same pressure by a linear scaling of temperature. The parameters n1 and n2 are simple functions of pressure and composition. This linear relation could be demonstrated for all (P, XNaCl) pairs where accurate volumetric data are available over a sufficiently large temperature interval. Extrapolations over as much as 300 °C predict high temperature data within their experimental uncertainty of 1-2\%. With a simple fit of parameters n1 and n2, the vast majority of several thousand experimental data points from the literature can be reproduced within experimental error, including dilute solutions in the compressible region. Although a strict theoretical foundation is lacking, this behavior can phenomenologically be rationalized as reflecting the relation between the linear to near-linear isochores of binary fluids to those of pure water. Accordingly, small deviations from linearity that amount to 0.1-0.2\% error in molar volume occur only at low temperatures where the pure water isochores behave non-linearly. This effect is accounted for by introducing a deviation function. Given its high accuracy, the formulation for the molar volumes could be integrated along isotherms-isobars to generate data for the specific enthalpy of binary solutions. In order to allow direct computation rather than numerical integration, a correlation scheme was developed that is mathematically similar to that for molar volumes. Specific enthalpies computed from the correlation typically agree within 1-3\% with those obtained from other studies. Similarly, isobaric heat capacities show good agreement with published data except for high salinities at moderate pressures and temperatures.}, added-at = {2011-01-19T18:05:50.000+0100}, author = {Driesner, Thomas}, biburl = {https://www.bibsonomy.org/bibtex/230ad4ceacfd187026b63a40a4087e090/thorade}, doi = {10.1016/j.gca.2007.05.026}, interhash = {c81d2eaf85cb25e973f1449cb78d646d}, intrahash = {30ad4ceacfd187026b63a40a4087e090}, issn = {0016-7037}, journal = {Geochimica et Cosmochimica Acta}, keywords = {2007 NaCl brine correlation enthalpy equation-of-state heat-capacity}, number = 20, pages = {4902 - 4919}, timestamp = {2011-07-21T11:47:52.000+0200}, title = {The system H2O-NaCl. Part II: Correlations for molar volume, enthalpy, and isobaric heat capacity from 0 to 1000 °C, 1 to 5000 bar, and 0 to 1 XNaCl}, url = {http://dx.doi.org/10.1016/j.gca.2007.05.026}, volume = 71, year = 2007 }