Numerical investigation of indirect freeze desalination using an ice maker machine
Numerical investigation of indirect freeze desalination using an ice maker machine
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DOI：
10.1016/j.enconman.2018.05.010
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发表时间：
2018-07
影响因子：
10.4
通讯作者：
H. Jayakody;R. AL-Dadah;S. Mahmoud
中科院分区：
文献类型：
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作者：
H. Jayakody;R. AL-Dadah;S. Mahmoud
为了解决缺水问题，海水淡化是一个有前景的解决办法，以满足不断上升的淡水需求。冷冻海水淡化是指海水冻结后，可以将盐类从水中分离出来，以生产饮用水。形成的冰是纯净的水，因为冰的晶格阻止了任何盐的夹杂。与其他海水淡化工艺相比，冷冻海水淡化的能耗较低，这是主要优势，因为熔化潜热(333.5 kJ/kg)约为蒸发潜热(2256.7 kJ/kg)的七分之一。利用CFD-Ansys-FLUENT软件对冷冻海水淡化过程进行了数值模拟，并与实验结果进行了比较，结果表明，结冰过程中温度变化的最大偏差为0.93%，冰和盐水盐度的百分比误差分别为15%和10.5%。参数分析结果表明，随着结冰温度的降低，冰块体积增大，在225 K结冰温度下，比257.15 K结冰多5 倍，但盐度水平较高，为3.02%。结果还表明，在冰层厚度约为4 mm时，在245 K的冰冻温度下，最低平均盐度为0.5%，高于世界卫生组织建议的0.1%的安全饮用水盐度水平。因此，对这0.5%的盐水进行了第二阶段冷冻处理，以产生所需的盐度水平。结果表明，在第二阶段冷冻过程中获得的平均冰盐度低于0.05%，为优质饮用水；在225 K温度下冷冻产生的纯冰量最大。这些结果突显了使用冷冻淡化生产饮用水的潜力。
To overcome the water shortage problem, sea water desalination is a prospective answer in order to cater for the escalating demand for fresh water. Freeze desalination is where the freezing of sea water permits the separation of salts from the water in order to produce potable water. The ice formed is of pure water as the ice crystal lattice prevents the inclusion of any salts. The lower energy usage of freeze desalination in comparison to other desalination processes is the key advantage; as the latent heat of fusion (333.5 kJ/kg) is about 1/7th that of the latent heat of vaporisation (2256.7 kJ/kg). CFD ANSYS fluent software has been used to simulate the freeze desalination process; results were compared with experimental tests showing a maximum deviation of 0.93% for the temperature change during the ice forming process and the percentage errors obtained for the salinities of ice and brine were 15% and 10.5% respectively. From parametric analysis study, results showed that, as the freezing temperature reduces, the volume of the generated ice block increases, where at 225 K freeze temperature, 5 times more ice was produced compared to that at 257.15 K, but with a high salinity level of 3.02%. Results also showed that the lowest average salinity achieved was 0.5% at an ice layer thickness of around 4 mm using a freezing temperature of 245 K. This is higher than the 0.1% salinity level recommended by the World Health Organization (WHO) standards as safe to drink water. Therefore, a second stage freezing process was applied to this 0.5% saline water to produce the required salinity level. Results showed that the achieved average ice salinity in the second stage of freezing process was below 0.05% which is regarded as good quality drinking water; also freezing at 225 K temperature produced the largest pure ice volume. These results highlight the potential of using freeze desalination to produce drinking water.