A method for measuring suspension density of crystals in acrystallizer by detecting pressure diflerence was discussed. When crystals in the range of 0.33-0.74mm were suspended in acylindrical apparatus with a distance of 4,000mm between the pressure gauges, the measured values were correlated with calculated ones. To prevent scaling, adding heated water or brine to the pressure gauge was effective. Based on these results, the practical application of this method for an industrial crystallizer with an actual heat exchange area of 400m2 was discussed.
A cylindrical pressure differencemeter, in which two pressure gauges were attached 2,000mm apart vertically, was tested to detect the Baume specific gravity of the solution (concentrated brine or mother liquid). Methods for measuring degree of Baume using a conventional densimeter and a refractometer were also tested. The Baum especific gravity obtained by the pressure difference method was in good agreement with that deterlnined by the densimeter. But the refraction index was not correlated with the Baume specific gravity. These physical properties were correlated with the change in the salt concentrations in the solution. An estimating method for the composition by combhling the ratio of salt concentration of brine obtained from the electro dialysis process was proposed.
Optimization of the Spray Flash Desalination System is carried out using the steepest descent method. The Spray Flash Desalination System is mainly composed of a spray flash chamber and a desalination condenser. In this system, warm sea water is evaporated in the spray flash chamber. The evaporated steam enters the desalination condenser and is condensed by the cold sea water. The consuming electric power per product water is used as an objective function. A desalination rate of 1000 tons per day using plate-type heat exchangers has been reported.
The effect of water salinity on the elemental composition of sagittae (otoliths) taken from male gobid fishes, Tridentiger obscurus obscurus, reared at a constant salinity (freshwater, 50% seawater and 100% seawater) for one month at 20°C, was studied using particle induced X-ray emission (PIXE). Nine elements were detected in the otoliths; Ca, Cl, Sr, K, P, Zn, Mn, Fe and Cu. The PIXE technique was proved to be an effective means for performing multielement analysis in small fish otoliths. The Cl, K and Sr concentrations, and each of their concentration ratios with Ca in the otoliths, were positively proportional to salinity of the fish rearing. The Mn and Zn concentrations, and Mn/Ca and Zn/Ca concentration ratios, were inversely proportional to the respective rearing salinity. No significant changes in Ca, P, Fe and Cu concentrations and P/Ca, Fe/Ca and Cu/Ca concentration ratios in the otoliths were found. These results suggest that it is possible to use the relationship between the elemental composition of otoliths and the environmental salinity as a means of reconstructing the salinity history of migratory fish.