摘要
采用膜蒸馏-结晶耦合技术处理盐水,可在高效、经济、环保地回收淡水的同时结晶分离出无机盐晶体。利用聚四氟乙烯平板膜进行了氯化镁溶液的直接接触式膜蒸馏-结晶(DCMDC)和真空膜蒸馏-结晶(VMDC)实验,研究了料液进口温度、循环速率、浓度以及真空度对水的膜透过量和盐截率等的影响。结果表明:在DCMDC处理氯化镁溶液过程中,水的膜透过量随着料液进口温度的升高、料液循环速率的提高而增大,随着料液浓度的增加而降低;在VMDC处理氯化镁溶液过程中,除了料液进口温度、循环速率、浓度对水的膜透过量有影响外,透过液侧的真空度对实验结果也有明显的影响,透过液侧的真空度增大水的透过速率增加,而且浓缩后的原料液在室温下冷却结晶,得到了形貌均一的六水合氯化镁晶体。在DCMDC和VMDC实验过程中,虽然盐截率随着实验的进行有所下降,但是不同的料液进口温度、循环速率、浓度以及真空度对盐截率的影响不显著。
Membrane distillation-crystallization coupled technology is efficient,economical,environmentfriendly.It can recycle fresh water while separate inorganic salt crystals from brine.Polytetrafluoroethylene（PTFE） flat-sheet membranes were used to separate water and inorganic salt crystals from magnesium chloride（MgCl2） solution via direct contact membrane distillation-crystallization （DCMDC） and vacuum membrane distillation-crystallization （VMDC）.The effect of the inlet tem-perature offeed,circulation rate,feed concentration and the degree ofvacuum on the experimental results were investigated. Results showed that the amount of permeated water through the membrane increased with the increase of inlet temperature of the feed and circulation rate,while decreased with the increase of feed concentration during DCMDC process.During the experiment of VMDC,the degree of vacuum in the permeated side had a significant impact on the results besides other factors.Increasing the degree of vacuum made the amount of permeate water increased.Not only fresh water was successfully recovered,but also MgCl2＊6H2 O crystals with a uniform morphology were got during the VMDC process.During the DCMDC and VMDC experiments,although the salt rejection decreased slightly with the experiment,the influence of the inlet temperature, the flow rate,the concentration offeed and the vacuum degree on the salt rejection was not significant.
出处
《无机盐工业》
CAS
北大核心
2017年第9期28-32,共5页
Inorganic Chemicals Industry
基金
化学工程联合国家重点实验室(SKL-Ch E-15A05)
青海省应用基础研究项目(2016-ZJ-702)
青海大学中青年基金项目(2015-QGY-1)
关键词
膜蒸馏-结晶
氯化镁
卤水
结晶
membrane distillation-crystallization
magnesium chloride
brine
crystallization
