What is the principle of vacuum freezing seawater desalination technology-Ocpuritech-img

What is the principle of vacuum freezing seawater desalination technology?

by:Ocpuritech     2021-03-25
What is the principle of vacuum freezing seawater desalination technology? Author: desalination technology refers to the excess salt and minerals in the water to get fresh water removal process. At present, the seawater desalination membrane methods installed in the world mainly include multi-stage flash evaporation, multi-effect evaporation and reverse osmosis. Over the past half century, it has fed more than 100 million people in the world and promoted the coastal areas of arid desert areas and developed countries. Economic and social development. However, what we are going to understand today is the vacuum frozen seawater desalination method. The vacuum freezing seawater desalination process includes the steps of degassing, pre-cooling, evaporative crystallization, ice crystal washing, steam condensation, etc., so that the desalinated aquatic products can meet the national drinking water standards, and it is an ideal seawater desalination method. Freezing method, that is, freezing sea water to freeze it, and the salt is separated out when the liquid sea water becomes solid ice. Both the freezing method and the distillation method have insurmountable drawbacks. Among them, the distillation method consumes a lot of energy and generates a lot of scale in the instrument, but the obtained fresh water tastes poor and is difficult to use. The pre-cooling of the frozen seawater desalination process. After the seawater is degassed, it can exchange heat with the concentrated brine and desalinated water discharged from the evaporative crystallizer, and is pre-cooled to near the freezing point of the seawater. Degassing of the frozen seawater desalination process. Because the non-condensable gas dissolved in the seawater will almost be released under low pressure conditions, and will not be condensed in the condenser. This will increase the pressure of the system, make the pressure in the evaporative crystallizer higher than the two-phase point pressure, and disrupt the operation. The triple point of sea water is a special point where the three phases of sea water vapor, liquid and solid coexist and reach equilibrium. If the pressure or temperature deviates from the three-phase point, the balance will be broken, and the three-phase will automatically tend to one or two phases. Vacuum freezing seawater desalination is a low-cost desalination method that uses the three-phase principle of seawater as a refrigerant to evaporate and freeze seawater at the same time, and then separate and wash the ice crystals to obtain desalinated water. Compared with the distillation method and membrane desalination method, the frozen seawater desalination method has low energy consumption, low corrosion and scaling, simple pretreatment, small equipment investment, and can treat seawater with high salt content. It is an ideal seawater desalination method. law.
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