PTFE双向拉伸微孔膜蒸馏脱盐实验研究
Experimental Study of Membrane Distillation Based on Brine Desalination by Biaxial Stretch Microporous Membrane of PTFE
作者：肖泽仪(四川大学 化学工程学院, 四川 成都 610065)；刘一才(四川大学 化学工程学院, 四川 成都 610065)；李健峰(四川大学 化学工程学院, 四川 成都 610065)；樊森清(四川大学 化学工程学院, 四川 成都 610065)
Author：XIAO Zeyi(School of Chemical Eng., Sichuan Univ., Chengdu 610065, China)；LIU Yicai(School of Chemical Eng., Sichuan Univ., Chengdu 610065, China)；LI Jianfeng(School of Chemical Eng., Sichuan Univ., Chengdu 610065, China)；FAN Senqing(School of Chemical Eng., Sichuan Univ., Chengdu 610065, China)
收稿日期：2018-03-09 年卷（期）页码：2019,51(1):256-262
期刊名称：工程科学与技术
Journal Name：Advanced Engineering Sciences
关键字：PTFE双向拉伸微孔膜;膜蒸馏;脱盐;膜传质系数
Key words：biaxial stretch microporous membrane of PTFE;membrane distillation;desalination;coefficient of mass transfer
基金项目：
中文摘要
为了高效生产淡水，同时开发新型膜材料的应用前景，采用PTFE双向拉伸微孔膜搭建真空蒸馏系统，并对NaCl溶液的脱盐性能进行了研究。设计正交实验，过程中保持膜下游恒定的绝对压力9 kPa， 考察了盐浓度0～80 g/L的溶液在进料温度20～60 ℃、进料流量40～160 L/h条件下，该种膜的真空膜蒸馏脱盐性能。实验结果表明，温度变化对膜通量影响最为显著且脱盐率略有变化，随浓度升高膜通量逐渐下降但脱盐率上升，流量增加能一定程度上提高膜通量但对脱盐率没有影响，其中40 g/L的盐溶液在进料流量120 L/h条件下，当进料温度为60 ℃时，膜通量达到18.4 kg/（m2·h）。在各种不同操作条件下产水电导率均小于5 μs/cm，计算脱盐率均超过99.9%，脱盐效果稳定。对真空膜蒸馏脱盐传质过程进行了分析，通过实验结果拟合了该膜的传质系数，发现其随温度线性增加，得出温度是影响膜传质系数的决定性因素，也说明了温度对膜通量的决定性影响。进行极差分析，得到温度是该过程的主要影响因素。进行重复试验证明该膜在实验过程中保持运行稳定，对于浓度低于80 g/L的盐溶液能有效避免膜污染问题。
英文摘要
In order to produce water efficiently and develop new membrane materials, plate and frame type membrane module was composed with biaxial stretch microporous membrane of PTFE, and vacuum membrane distillation system was set up to explore the desalination performance of NaCl solution. Orthogonal experiment was designed and the effect of feed temperature, flow rate, and concentration on water production were studied at 9 kPa absolute pressure degree on the one side of membrane. It was found that the temperature changed has the most significant influence on the membrane flux and the desalination rate changed slightly. With the increase of concentration, the membrane flux gradually decreases but the desalination rate increases. The increase of feed flow rate would increase the membrane flux, but no effect on the desalination rate. the flux has reaches 18.4 kg/(m2·h) at the conditions of 120 L/h feed flow rate and 40 g/L concentration when temperature at 60. More than 99.9% desalination rate and less than 5 μs/cm conductivity of produced water are found at different operation conditions. The process of mass transfer of vacuum membrane desalination was analyzed and coefficient of mass transferwas calculated by results of experiment. It was concluded that temperature is the important factor of coefficient of mass transfer and membrane flux because the coefficient of mass transfer increase linearly with it. Range analysis was developed and showed that temperature is the main influencing factor of the process. Repeated trials was studied and showed that the membrane remains stable running in the process of experiment. It was concluded that biaxial stretch microporous membrane of PTFE can be used for NaCl solution which concentration less than 80 g/L.
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