浓海水冷冻脱盐技术研究

Study on Freezing Desalinization Technology of Desalinated Seawater

通过实验室冷冻离心实验,研究了浓海水的冷冻脱盐技术。实验研究了离心转速对冰冻的浓海水的脱盐和脱除钙镁离子的影响,并对多步冷冻脱盐前后余冰和浓海水的盐度分别进行分析,以及利用ICP-MS对其主要离子含量进行测定。实验结果表明,离心转速变化对冰冻浓海水脱盐、脱除钙镁离子的影响显著。各实验离心转速条件下,脱盐和脱除钙镁离子均有较好效果,脱除率均达到88.5%和87.4%以上。随着离心转速的提高,脱盐率提高,转速4000r/min达到最大,但是其变化幅度减小,进一步提高转速对脱盐率和钙镁离子脱除率的提高影响不大。经过多步冷冻脱盐发现,一次冷冻离心分离,得到的余冰的盐度脱除达到99.0%。通过与原浓海水离子含量相比,钾钙钠镁等主要离子含量降低为原浓海水的3%以下。而多步离心分离之后,得到的浓海水的盐度达到原浓海水的3.3倍。每步实验,均有低盐度、低离子含量的冰生成,冰的产量达到被处理的浓海水总体积的2/3以上。

Effects of desalination technology and centrifugal rotational speed on desalinated seawater were studied by freezing centrifugal experiments at the laboratory. The experimental results show that the effect of rotational speed variance on the desalination and its efficiency are obvious under the same experiment condition. The desalination removal rate was above 88.5 % and the removal of Ca^2＋ and Mg^2＋ was above 87.4 % under different rotational speeds. The desalination removal rate increased with the raise of rotational speed. When the centrifugal rotational speed was 4 000 r/min, the rate of desalination of desalinated seawater ice was maximum and its value was 99.0 %. But rate change was getting small. The impact of raising rotational speed was not obvious towards desalination removal rate and the removal of Ca^2＋ and Mg^2＋. The experience of desalination technology separated the ice and brine after the treatment. The salinity and main ion content were determined both of the ice and brine. The：experimental results show that the ice salinity removal rate was 99.0 % after first freezing treatment. Comparing with the original desalinated seawater, the content of main ions of K^＋, Ca^2＋, Na^＋, Mg^2＋ was only 3 % after first freezing treatment. And the salinity of brine is 3.3 times the original desalinated seawater. By every steps of the experiment, the ice of low salinity and low content was left and the amount of ice was 2/3 of the original amount of desalination seawater.