海水淡化副产浓海水电渗析制盐工艺研究

发布时间：2018-02-07 09:47

  本文关键词： 海水淡化 浓海水 电渗析 海盐 水盐体系　出处：《天津大学》2015年硕士论文　论文类型：学位论文

【摘要】：海水作为水资源的重要组成部分,其有效利用是解决我国水资源短缺的重要途径之一。海水淡化技术的成熟,催生了海水淡化项目建设,在一定程度上缓解了沿海地区尤其是经济发展迅速的沿海城市用水紧张问题。在大型海水淡化工程项目建设时,其副产的高浓度海水将对封闭海域的生态环境产生一定的影响,根据循环经济发展规划及海洋生态环境保护要求,浓海水高效利用技术研究将成为海水资源开发利用的先决条件。电渗析作为高效膜分离技术是选择性分离电解质离子的有效方法之一,在国外已被广泛应用。在国内制盐行业中应用电渗析技术,最近几年取得了一定的研究进展,但至今未见工业化应用报道。本文以某电厂排出的5.4?Be'浓海水为原料,研究浓海水的净化、电渗析、蒸发浓缩、析盐、析钾、制取低钠盐等工艺及其工业化的可行性。发现,浓海水净化后通过电渗析膜组件,Na+、K+、Cl-等一价离子选择透过性较好,控制脱盐率80%时,所得浓盐水盐度≥20%,其中:NaCl≥210g/l、KCl≥6g/l;浓水量为原料量的15.5%,浓缩回收率:NaCl≥80%、KCl≥85%,电渗析能耗≤40KW·h/m3。浓盐水在蒸发结晶过程中:108.5℃时析出精制盐,回收率60%;浓缩液蒸发终止115℃,氯化钠结晶析出率≥97%,精制盐经脱水干燥后NaCl≥99.1%;冷却结晶温度25℃氯化钾结晶析出率≥60%,精制氯化钾产品中KCl≥99.1%;低温蒸发真空度0.098MPa,溶液蒸发终止温度42℃,低钠盐产品NaCl≥68%、KCl≥30%、杂质盐含量1%;蒸发结晶母液NaCl≤2%、KCl≤3.5%,浓海水提取率:NaCl≥80%、KCl≥85%,高于盐田制盐海水利用率,精制盐产品折合市场价成本约350元/吨,研究的海水淡化浓海水电渗析制盐工艺具有工业化生产应用价值。
[Abstract]:As an important part of water resources, the effective utilization of seawater is one of the important ways to solve the shortage of water resources in China. The maturity of seawater desalination technology has given birth to the construction of desalination projects. To some extent, the shortage of water in coastal areas, especially in coastal cities with rapid economic development, has been alleviated. In the construction of large-scale desalination projects, the high concentration of seawater by-products will have a certain impact on the ecological environment of the enclosed sea areas. According to the development plan of circular economy and the requirements of marine ecological environment protection, The study on high efficiency utilization of concentrated seawater will be a prerequisite for the exploitation and utilization of seawater resources. Electrodialysis is one of the effective methods for selective separation of electrolyte ions as a high efficiency membrane separation technique. The application of electrodialysis technology in the domestic salt industry has made some progress in recent years, but no industrial application report has been seen so far. In this paper, the discharge of a power plant 5.4? The process of purification, electrodialysis, evaporation and concentration, salt evolution, potassium evolution, preparation of low sodium salt and the feasibility of industrialization of the concentrated sea water were studied, such as the purification of concentrated sea water, electrodialysis, evaporation and concentration, salt evolution, potassium evolution and the feasibility of industrialization. When the desalination rate is controlled by 80%, the selective permeability of ion such as Na ~ (+) K ~ (+) Cl ~ (-) is better through electrodialysis membrane assembly after purification of concentrated seawater. The salinity of concentrated brine is 鈮，

本文编号：1494089