Relative enthalpies of sea salt solutions at 0.deg. to 75.deg.

Abstract

The relative enthalpy of seawater, its solutions, and concentrates, the apparent enthalpy of sea salts, and the relative partial enthalpies of sea salts and water in seawater solutions, in the temperature range 0-75°C and salinity range 0-12%, have been evaluated from accurate calorimetric measurements of heats of mixing of sea salt solutions. The data were correlated by an extended Debye-Huckel theory. The results are consistent with the published data on heat capacity and heat of mixing.

Physico-Chemical Controls on Seawater

“…The results from 0 to 40 C and S A ¼ 0 to 40 g kg À1 are in good agreement with measurements made on samples of known chlorinity and salinities calculated from the earlier equation of state (Millero and Poisson, 1981). The free energy of seawater has been estimated over a range from 0 to 250 C and S A to 180 g kg À1 (Millero and Pierrot, 2005) by including the studies of Bromley and coworkers (Bromley, 1968a,b;Bromley et al, 1967Bromley et al, , 1970Bromley et al, , 1974Singh and Bromley, 1973). The free energy of seawater has been estimated over a range from 0 to 250 C and S A to 180 g kg À1 (Millero and Pierrot, 2005) by including the studies of Bromley and coworkers (Bromley, 1968a,b;Bromley et al, 1967Bromley et al, , 1970Bromley et al, , 1974Singh and Bromley, 1973).…”

Thermodynamic properties of sea salt solutions

“…For extrapolation over the wide temperature range reported, the data on heat capacity of sea salt solutions of Bromley et al (1970) and the enthalpy data of Singh and Bromley (1973) were used. These latter sets of data have been shown to be in good agreement with several sets of experimental measurements of enthalpy and heat capacity such as the recent data of Millero e t al.…”

“…Equation (18), however, has four adjustable parameters and the data in Table 1 is insufficient and over too limited a range to accurately determine all of them. Consequently, the values for B" and B3 were obtained from the more extensive data to 200°C on heat capacities of Bromley et al (1970), and B1 from data on heats of mixing by Singh and Bromley (1973). Only B2 was determined from the data in Table 1 and the data of Rush and Johnson (1966).…”

“…Pure water properties were obtained from the National Engineering Laboratory (1964) Steam Tables. Relative enthalpies were taken from Singh and Bromley (1973). The equations were solved by successive approximation and numerical integration using x is the wt.…”

Optimization of multi-effect distillation process using a linear enthalpy model

“…(5) [26,27]. In essence the adopted model is linearly dependent on both pure water enthalpy and salt enthalpy.…”