真空式與直接接觸式薄膜蒸餾於海水淡化之性能比較

Comparison on the performances of VMD and DCMD in desalination

葉國麟(Kuo-Lin Yeh)

指導教授 ： 鄭東文

淡江大學/工學院/化學工程與材料工程學系碩士班/碩士(2012年)

https://doi.org/10.6846/TKU.2012.00447

摘要

本研究實驗是利用Toyo公司所生產之聚四氟乙烯(Polytetrafluoroethylene；pore size=0.2μm)比較直接接觸式薄膜蒸餾(Direct Content Membrane Distillation)與真空式薄膜蒸餾(Vacuum Membrane Distillation)兩者系統用於海水淡化時之效能。實驗是以原型模組與改良模組(凸出型)改變進料溫度、進料流量、曝氣，比較兩系統其滲透通量之差異與影響。
實驗結果可以發現，提高進料溫度對於兩系統皆能明顯增加滲透通量，極化現象也較嚴重。而增加進料流在VMD系統提升通量之效能比DCMD來得高。改變模組傾斜角則是由於不穩定自然對流的關係使得滲透通量提昇，在DCMD系統時皆能提昇滲透通量，其中以傾斜角度45o為最高之滲透通量，但在VMD系統自然對流效果不顯著，對於滲透通量提昇無提昇效果。曝氣時於DCMD系統皆能有效提升通量，VMD則在傾斜角大於45o曝氣才有效果。改良凸出模組(Convex)增加了對膜面之剪應力，對於VMD與DCMD系統皆能有效減緩極化效應使得滲透通量增加，通量提升分別可達15.8%與37.3%。

關鍵字

真空式薄膜蒸餾 ； 直接接觸式薄膜蒸餾 ； 聚四氟乙烯 ； 流動通道

並列摘要

The flat PTFE membrane and hollow fiber PVDF membrane were used in studying on the flux performance in the operating of DCMD and VMD. Operating parameters included temperature difference, feed flow rate, module inclination angle, gas flow rate. The convex design in the feed chance was also included.
The experimental results show that increasing the temperature difference will increase the permeate flux, but also heighten the polarization phenomena. The performance of Increasing feed flow in DCMD system higher than VMD system. In DCMD system, the permeate flux increased, and reached a maximum at about 45°. Aeration in DCMD system can enhance the flux, but VMD in the angle greater than 45o aeration will be effective. It is noted that the convex design in the feed channel as module inclined increases the shear stress on the membrane, thus, effectively reduces the polarization phenomena and increases the permeate flux. The flux enhancement in DCMD and VMD were improved to about 37.3% and 15.8% percent.

並列關鍵字

Vacuum membrane disstillation ； Direct contact membrane distillation ； Channel ； PTFE

參考文獻

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