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|Other Titles: ||A study on performance of PVDF hollow fiber in membrane distillation|
|Authors: ||林智偉;Lin, Jhih-Wei|
|Keywords: ||聚偏二氟乙烯;中空纖維薄膜;真空式薄膜蒸餾;直接接觸式薄膜蒸餾;poly(vinylidene fluoride);hollow fiber membrane;Vacuum Membrane Distillation;Direct contact membrane distillation|
|Issue Date: ||2015-05-04 09:58:07 (UTC+8)|
|Abstract: ||本研究以實驗室合成之聚偏二氟乙烯(poly(vinylidene fluoride), PVDF)中空纖維膜組裝之模組進行真空式薄膜蒸餾(vacuum membrane distillation)及直接接觸式薄膜蒸餾(direct contact membrane distillation)實驗，進料溶液為3.5 wt%之鹽水溶液，操作參數為進料溫度(50~70 oC)及進料速率(0.1~0.4 L/min)，真空式薄膜蒸餾其真空度為持在8 kPa，直接接觸式薄膜蒸餾之冷水側溫度為17.5 oC及進料速率0.4 L/min。|
In this study, laboratory made poly(vinylidene fluoride), PVDF, hollow fiber membranes were used in vacuum and direct contact membrane distillation of saline solution. The feed solution was 3.5 wt% NaCl solution, the operating parameters included feed temperature (50 ~ 60 oC), feed rate (0.1 ~ 0.4 L / min), the vacuum pressure in the permeate side was controlled at 8 kPa for vacuum membrane distillation, and cooling water controlled at 17.5 oC with rate 0.4 L / min for direct contact membrane distillation.
The hollow fiber membranes were prepared by varying the composition of the coagulation bath. There were five conditions, which water phase、10、20、40、60 wt% triethylphosphate (TEP) solution. The outer skin of the hollow fiber membrane was improved by changed the bath from hard coagulation (water bath) to soft coagulation. Analysis the structure by SEM morphology, which membrane have large pore size in the outer surface by increasing the weight percent of TEP in coagulant bath.
In the vacuum and direct contact membrane distillation experiment, raising the temperature of the feed can significantly increase the flux, but the polarization phenomena become more serious. In addition, the membrane surface will have fouling phenomenon that NaCl was separated out to the shell side membrane surface in vacuum membrane distillation. This situation will cause decrease the effective area of the membrane and reduce the flux. Increasing feed flow rate has a finite effect on increasing the flux, but the temperature polarization phenomenon can be reduced by the feed flow rate as higher feed temperature.
The experimental results showed the higher flux performance on direct contact membrane distillation which prepared by higher weigh percent of TEP coagulation bath solution but not obviously in the vacuum membrane distillation. The large pore size membrane flux which increased by higher inlet temperature more obvious then the small one. Furthermore, the short module have higher flux then long module in the same inlet condition.
|Appears in Collections:||[化學工程與材料工程學系暨研究所] 學位論文|
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