超滤组合工艺处理高浓度制盐卤水

发布时间：2018-07-08 08:47

本文选题：超滤 + 组合工艺　；参考：《天津工业大学》2017年硕士论文

【摘要】：盐,不仅是人类存所必须的营养元素,也是化工生产的重要原料。盐化工行业的发展对我国海洋经济的发展起着至关重要的作用,卤水中的主要成分氯化钠,是盐化工行业重要基础原料。近些年海洋污染加剧,由海水浓缩所得的制盐卤水中也含有颗粒物、胶体、有机物、矿物质和微生物等污染物,为了保证食用盐的品质和盐化工行业的健康发展,卤水净化就显得日益重要。与传统卤水净化工艺相比,超滤具有占地面积小、化学污染少、自动化程度高等优点,然而膜污染是限制膜推广和应用的主要问题。膜前进行有效的预处理可以缓解膜污染,因此本文采用混凝气浮+砂滤+超滤组合工艺处理高浓度制盐卤水。评估了不同运行通量及不同预处理条件对不可逆膜污染的影响,结果表明:混凝气浮+砂滤预处理可有效的缓解不可逆膜污染,20L/m~2·h为推荐运行通量。计算了各处理单元的吨水能耗和卤水回收率,气浮单元、砂滤单元、超滤单元的吨水能耗依次为0.26kw · h/m~3、0.19kw · h/m~3、0.12kw·/h/m~3。超滤20L/m~2 · h的卤水回收率为90%,砂滤和气浮单元卤水基本全部回收。分析了单周期膜污染速率影响因素,运行通量越高,单周期膜污染越快,混凝气浮+超滤预处理可以有效降低单周期膜污染速率。对比了不同处理工艺下的卤水处理效果,结果表明:混凝气浮+砂滤对卤水TOC、浊度、SS都有较好的去除效果,其去除率依次为35.6%～38.9%、38.8%～54.7%和68.7%～73.4%,混凝气浮+砂滤+超滤对TOC和浊度去除率提高到38.6%～44.2%和99.6%～99.7%;确定了聚合氯化铝最佳投加量和卤水在砂滤器内的适宜停留时间,聚合氯化铝的最佳投加量为30～40ppm,卤水在砂滤器内的停留时间应为3～3.5min。
[Abstract]:Salt is not only a necessary nutrient for human beings, but also an important raw material for chemical production. The development of salt chemical industry plays an important role in the development of marine economy in China. Sodium chloride, the main component of brine, is an important basic raw material in salt chemical industry. In recent years, marine pollution has intensified, and the salt brine obtained from the concentration of seawater also contains particulate matter, colloid, organic matter, minerals and microorganisms. In order to ensure the quality of edible salt and the healthy development of salt chemical industry, Brine purification is becoming increasingly important. Compared with the traditional brine purification process, ultrafiltration has the advantages of less occupied area, less chemical pollution and higher degree of automation. However, membrane fouling is the main problem limiting the popularization and application of membrane. The membrane fouling can be alleviated by effective pretreatment before membrane, so this paper uses the combined process of coagulation and floating sand ultrafiltration to treat high concentration salt brine. The effects of different operating fluxes and pretreatment conditions on irreversible membrane fouling were evaluated. The results showed that coagulation flotation sand pretreatment could effectively mitigate irreversible membrane fouling for 20 L / m ~ 2 h. The energy consumption of ton water and brine recovery, air floatation unit, sand filter unit and ultrafiltration unit of each treatment unit are calculated in order of 0.26kw h / m ~ (3) ~ 0.19kw / h / m ~ (3) ~ 0.12kw / h ~ (-1) / m ~ (3). The recovery rate of brine in ultrafiltration 20 L / m ~ (2) h is 90%, and that of sand filter and air floatation unit is almost all recovered. The influencing factors of single-cycle membrane fouling rate were analyzed. The higher the running flux, the faster the single-cycle membrane fouling. The coagulation air flotation ultrafiltration pretreatment could effectively reduce the single-cycle membrane fouling rate. The effects of brine treatment under different treatment processes were compared. The results showed that coagulation air flotation sand filter had better removal effect on toc and turbidity SS of brine. The removal rates of TOC and turbidity were 35.6% 38.9% and 68.7% and 73.4%, respectively. The removal rates of TOC and turbidity were increased to 38.6% and 99.6% respectively. The optimum dosage of polyaluminium chloride and the proper residence time of brine in sand filter were determined. The optimum dosage of polyaluminium chloride is 30 ~ 40 ppm, and the residence time of brine in sand filter should be 3 ~ 3. 5 min.
【学位授予单位】：天津工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TQ028.8;TS392

【参考文献】