Thermodynamic and Kinetic Properties of Natural Brines

Abstract

The physical chemistry of natural brines made up of mostly NaCl has been studied over the years. In this article, the work on the thermodynamics and kinetics of processes in NaCl brines will be examined. The importance of ionic interactions of the processes will be stressed. This will include the pressure-volume-temperature and physicalchemical properties of NaCl and other brine salts from 0 to 6 m, 0 to 200°C, and 0 to 1,000 bar applied pressures. Acid-base, gas-liquid, solid-liquid, and ion-complex formation processes in NaCl are examined. Equations that can be used to estimate the equilibria in NaCl are given. Pitzer models are discussed that can be used to estimate ionic equilibria in brines. The oxidation of Fe(II) and Cu(I) with O 2 and H 2 O 2 and the reduction of Cu(II) with H 2 O 2 in NaCl are examined in terms of ionic complexes of metals with OHand CO 3 2-. The oxidation of H 2 S with O 2 and H 2 O 2 is also examined in NaCl media. Equations are given that can be used to estimate the effect of ionic interactions on kinetic processes in NaCl.

Geochemical and Process Engineering Challenges for Geothermal Power Generation

“…Methods for calculating density, heat conductivity and viscosity depending on temperature, pressure and salinity are given in [31]. Methods for calculating the specific heat capacity are given in [32] and [33]. However the validity of available methods is limited and often these methods do not comprise the site specific fluid composition or the required temperature and pressure levels.…”

History of the Equation of State of Seawater

“…In recent years, we have used the ionic interaction model of Pitzer (1991) to examine the PVT and thermochemical properties of seawater (Pierrot and Millero, 2000;Millero and Pierrot, 2005). These models allow reasonable estimates of the properties of seawater as well as other electrolyte mixtures over a wide range of pressure and temperature (Millero, 2009 (Fofonoff and Millard, 1983) also "blessed" equations for the specific heat capacity (Millero et al, 1973b), sound speed in seawater , and the freezing point temperature derived from the free energy of seawater (Millero and Leung, 1976). JPOTS approved equations for the conversion between hydrostatic pressure and depth, the calculation of the adiabatic lapse rate, and the calculation of WG 127 developed a collection of algorithms that incorporate our best knowledge of the thermodynamics of seawater (IOC et al, 2010).…”

Energetic Use of EGS Reservoirs

“…Methods for calculating density, heat conductivity, and viscosity depending on temperature, pressure, and salinity are given for example, in McDermott et al (2006). Methods for calculating the specific heat capacity are given for example, in Thomsen (2005) and Millero, F. (2009). In case methods suitable for calculating these properties are not available, the data need to be measured.…”