Theoretical And Experimental Investigation On Centrifugal Desalting Of Sea Ice

This research is a project funded by Key Projects in the National Science & Technology Pillar Program in the Eleventh Five-year Plan Period to study sea-ice desalination and its continuous production. The salinity of sea ice is mainly from brine salinity cell wrapped inside when sea ice is freezing and According to it, the methods of centrifugal separation of sea ice follows: break the ice so that salt brine is exposed, and then apply very large gravity by centrifuge, remove sea brine and dilution sea ice.In this paper, the characteristics of sea ice are summarized. Through the theoretical analysis, a theoretical formula between salinity and time after centrifugal desalting of sea ice, S(t)= PK1/t^1/2, is obtained. It shows good agreement to contrast the results of theoretical formula to the data in the literature. From the numerical simulation of the process of filtration and phase transition of centrifugal desalting of sea ice, the following conclusions were got: it is about 0.12s to cost in the process of filter, it is easy to freeze for the brine in the ice surface at low temperature.Through the experimental, the effect of particle size, the ratio of seawater added, temperature and so on is determined. The experimental result shows that the diluted salinity shows the trend of increase to decrease with the particle size, and reach the minimum when the particles is about 6-9mm;the diluted results get better with increasing of temperature; the ratio of seawater added have a considerable influence on the diluted salinity, but affected by temperature: adding seawater is very beneficial for centrifugal desalting when the temperature is higher than -2℃; and the best ratio is 60% ,but it is worse when the temperature is less than -6℃.In order to facilitate feeding for centrifuge, a new kind of equipment of feeding and mixing for it is designed which can stir and push at the same time and solve the material jam and save energy by combining traditional blender and push feeder. The continuous system of centrifugal desalting of sea ice is realized through the site layout and the equipment connections. From the experiment and calculation, the current salinity of continuous centrifugal desalting of sea ice can be reduced to 1.0¹.5‰.