嵌入3D列印之紊流促進模組於直接接觸式薄膜蒸餾系統之理論與實驗研究

薄膜蒸餾技術用於海水淡化以製造之純水可提供民生及工業使用，因其具有裝置設置簡易、低能耗、可操作於常壓、高介面面積等優點，故成為著墨研發的海水淡化技術之一。本研究之直接接觸式薄膜蒸餾式以多孔性之複合膜材做為介質，利用薄膜兩側之流體溫度差異而導致的飽和蒸汽壓不同，作為驅使水蒸氣經過薄膜之驅動力，達到分離之效果。然而，薄膜蒸餾系統會因流體流經模組產生之物理現象對系統產能有顯著的負面影響，此研究是針對其中溫度極化現象，以3D列印為紊流促進因子，結合數學模型理論，討論改善之效能。本研究針對薄膜蒸餾效率改善研究，有以下幾點方向： (1)設計新型紊流促進因子(Eddy promoter) ，以求有效改善系統內部的溫度極化現象進而提升系統產能，並歸納出經驗公式，描述此型式的紊流促進因子對於通道內部熱對流效應的影響。 (2) 探討設計參數及操作條件對於薄膜蒸餾系統之流體溫度分佈、溫度極化現象、純水透膜通量增加百分率與水力損耗提升百分率的影響。 (3) 藉由一維數學模型針對薄膜蒸餾設備的熱量與質量傳送機制進行研究，配合實驗分析以驗證經驗公式與數學模型的正確性。研究結果顯示，溫度極化係數會隨著流體進口溫度的增加而減少，隨著體積流率的增加而增加，逆流操作的透膜通量皆大於順流操作的透膜通量，平均約為13.9%。

關鍵字

直接接觸式薄膜蒸餾；透膜通量；溫度極化； 3D列印；紊流促進因子

並列摘要

The modeling equations for predicting permeate flux in direct contact membrane distillation (DCMD) modules with inserting the additive manufacturing turbulent promoter were investigated theoretically and experimentally. The DCMD module can be performed at middle temperature operation (about 45 °C to 60 °C) of hot inlet saline stream associated with a constant temperature of cold inlet stream. The existence of temperature difference in operating the DCMD module means that the membrane surface temperatures always contact with bulk temperatures which a temperature gradient was built up and called temperature polarization, may cause a considerable heat loss. The additive manufacturing turbulent promoter acting as an eddy promoter could not only strengthen the membrane stability for preventing from vibration but also enhance the permeate flux with lessening temperature polarization effect. Attempts to reduce the disadvantage temperature polarization effect were made implementing turbulent promoters to elevate the flow characteristic in improving permeate flux productivity. Experimental study has demonstrated its technical feasibility, and a considerable performance enhancement was achieved for the new design of the DCMD system.

並列關鍵字

Direct contact membrane distillation ； Permeate flux ； Temperature polarization ； 3D Printed Turbulent Promoter

參考文獻

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嵌入3D列印之紊流促進模組於直接接觸式薄膜蒸餾系統之理論與實驗研究

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