Preliminary Study Of Brine Systems Continuous Heterogonous Phase Equilibrium In Gravity Field

The study of Maintaining concentration gradient areas and concentration distribution of solar pond is important parts of solar pond study. We thought about that weather it’s possible that the concentration gradient of the cheap substance (NaCl, MgCl2 solution) can be generating with the effect of gravity. In the ocean, salinity has an effect on the motion of ocean. Weather gravity effects the salinity distribution? For this confusion, we explored concentration distribution of brine solution in gravity field.To explore concentration distribution of brine solution in gravity field, we investigated NaCl, KCl, MgCl2, CaCl2, BaCl2 five kinds of binary solutions in experiment, studied the theory of unsaturated salt aqueous solutions concentration gradient in gravity field, and investigated supersaturated NaNCl2, CaCl2 solutions in experiment.(1) Unsaturated salt aqueous solutions concentration gradient in gravity field in experiment:We designed one meter vertical columns container, and measured the salt concentration and density at four column heights of different initial concentration solutions after regular time interval at 25 degree. The experimental results showed that the concentration differences were undetectable.(2) Unsaturated salt aqueous solutions concentration gradient in gravity field in theoretic study:On the ground of theory of solution thermodynamic equilibrium equation in gravity field which Larson studied, we derived the equation of concentration gradient of unsaturated salt solution column We set c of the equation as water, and got the water activity gradient. Then we got the concentration gradient by exploring the relationship between water activity and concentration. On the basic of the theory study, we calculated concentrated gradient of one meter solution columns of five kinds of unsaturated salt solutions and the difference of top and bottom of concentration of different height unsaturated solution columns and the ratios of concentration of top and bottom of different concentration solution columns. Theoretical calculation conclusions were as follows:1. The difference of one meter unsaturated binary solution column is so little that can be detected.2. Compared with NaCl solution, the difference of KCl solution conlum is more significant for the weight of molecular KCl is lager.3. The concentration gradient of unsaturated CaCl2 and MgCl2 solution columns are not conspicuous for the bond of molecular CaCl2, MgCl2 with water molecular is strong.4. The most significant difference of solution column is BaCl2 solution.(3) Supersaturated salt aqueous solutions concentration gradient in gravity field in experiment:We measured supersaturated NaNCl2 and CaCl2 solution columns concentration gradient after 24 hours. It showed that the contracture of supersaturated solution was different form unsaturated solution, and these gradients resulted form the presence of solute clusters.