A computer program for the simulation of evaporation of natural waters to high concentration

Abstract EQL/EVP is a FORTRAN 90 program that simulates the evaporation of dilute waters as well as concentrated brines. The code calculates stepwise the composition of the evaporated solution and the amounts of precipitated minerals. Activity coefficients are based on the Pitzer's interaction model which allows calculation to high ionic strength. The Newton–Raphson method is used to solve a set of linear mass-balance and non-linear mass-action equations. The simulation may be carried out in equilibrium mode where minerals are allowed to redissolve into the solution or in fractional crystallization mode where minerals are removed as they precipitate. Temperature dependence of various parameters and mineral solubility products are tentatively included between 0 and 50°C. The code processes all invariant points: those where the activity of water is constrained by several minerals and the invariant end-points. The code may be a useful tool for understanding hydrological and geochemical processes in arid regions.

[1]  R. A. Robie,et al.  Thermodynamic properties of minerals and related substances at 298.15 K and 1 bar (10[5] pascals) pressure and at higher temperatures , 1995 .

[2]  W. L. Marshall,et al.  Amorphous silica solubilities IV. Behavior in pure water and aqueous sodium chloride, sodium sulfate, magnesium chloride, and magnesium sulfate solutions up to 350°C , 1982 .

[3]  N. Møller,et al.  The prediction of mineral solubilities in natural waters: A chemical equilibrium model for the Na-Ca-Cl-SO4-H2O system, to high temperature and concentration , 1988 .

[4]  Kenneth S. Pitzer,et al.  Thermodynamics of concentrated electrolyte mixtures and the prediction of mineral solubilities to high temperatures for mixtures in the system Na-K-Mg-Cl-SO4-OH-H2O , 1987 .

[5]  D. Kinsman.  Evaporites: Relative Humidity Control of Primary Mineral Facies , 1976 .

[6]  K. Pitzer,et al.  The thermodynamics of aqueous carbonate solutions II. Mixtures of potassium carbonate, bicarbonate, and chloride , 1982 .

[7]  W. L. Marshall,et al.  Amorphous silica solubilities—II. Effect of aqueous salt solutions at 25°C , 1980 .

[8]  John H. Weare,et al.  The prediction of mineral solubilities in natural waters: A chemical equilibrium model for the NaKCaMgClSO4H2O system at temperatures below 25°C , 1990 .

[9]  N. Møller,et al.  The prediction of mineral solubilities in natural waters: The Na-K-Mg-Ca-H-Cl-SO4-OH-HCO3-CO3-CO2-H2O system to high ionic strengths at 25°C , 1984 .

[10]  Simulation de l'évaporation sur micro-ordinateur , 1984 .

[11]  W. L. Marshall.  Amorphous silica solubilities—III. Activity coefficient relations and predictions of solubility behavior in salt solutions, 0–350°C , 1980 .

[12]  W. L. Marshall,et al.  Amorphous silica solubilities V. Predictions of solubility behavior in aqueous mixed electrolyte solutions to 300°C , 1982 .

[13]  E. C. Beutner.  Slaty cleavage and related strain in Martinsburg Slate, Delaware Water Gap, New Jersey , 1978 .

[14]  B. Fritz.  Étude thermodynamique et simulation des réactions entre minéraux et solutions : application à la géochimie des altérations et des eaux continentales , 1975 .

[15]  David L. Parkhurst,et al.  A computer program incorporating Pitzer's equations for calculation of geochemical reactions in brines , 1988 .

[16]  Marc W. Bodine,et al.  The SALT NORM : a quantitative chemical-mineralogical characterization of natural waters , 1986 .

[17]  Jerry P. Greenberg,et al.  The prediction of mineral solubilities in natural waters: A chemical equilibrium model for the Na-K-Ca-Cl-SO4-H2O system to high concentration from 0 to 250°C , 1989 .

[18]  John H. Weare,et al.  The prediction of mineral solubilities in natural waters: the NaKMgCaClSO4H2O system from zero to high concentration at 25° C , 1980 .

[19]  John H. Weare,et al.  The prediction of borate mineral equilibria in natural waters: Application to Searles Lake, California , 1986 .