A model of freeze desalination for predicting salt concentration in ice using the laws of conservation of matter & mass

Abstract

The assessment of freeze desalination (FD) efficiency is lagging behind due to the lack of an effective means of determining ice total dissolved solid (TDS). In this paper, an ice TDS prediction model was constructed by utilizing the law of conservation of matter (LCMat) and conservation of mass (LCMas) in the icing process. It was concluded that the average TDS ice crystals in any icing process was correlated with the TDS of the raw (concentrated) water at the starting of freezing, the salt mass change rate of the concentrate water, and the volume of ice crystals. A one-way FD test was carried out using the saltwater from South Xinjiang, and the exponential equation model and linear equation model of LCMat-LCMas were derived, and the simulation accuracy of LCMat-LCMas was verified by using the test data. The results show that the model has high prediction accuracy. The exponential equation model is suitable for predicting the ice TDS for ice with thickness within 15 cm, and the linear equation is suitable for predicting the ice crystal TDS for ice thicker than 15 cm. Further validation of the model accuracy is needed for larger cooled areas and icing thicknesses, and multidirectional icing processes.

Keywords

• Freeze desalination
• TDS of ice
• Model
• The law of conservation of matter
• The law of conservation of mass