直接接觸薄膜蒸餾: 疏水/親水複合膜之數值模擬與探討

Hydrophobic/hydrophilic composite membranes of direct contact membrane distillation : Numerical simulation and discussion

李彥輝(Yan-Huei Li)

指導教授 ： 許文震

國立清華大學/工學院/動力機械工程學系/碩士(2013年)

https://doi.org/10.6843/NTHU.2013.00170

摘要

近年各國紛紛投入海水淡化技術的開發與研究，希望能因應不斷成長的用水需求。隨著全球暖化議題的增溫與化石燃料價格的成長，低階廢熱(low grade waste heat)與再生能源的使用逐漸受到人們的重視，這使得薄膜蒸餾法(membrane distillation, MD)，一項可以利用廢熱與再生能源的淡化技術，受到了關注。本文將研究薄膜蒸餾法的其中一種，直接接觸薄膜蒸餾(direct contact membrane distillation, DCMD)搭配疏水/親水複合膜的熱質傳現象。
本研究針對單層疏水膜、疏水/親水複合膜依據不同的理論分別撰寫Fortran程式進行模擬，並與實驗室前人的實驗數據進行比較，最後調整參數以了解疊合式複合膜的可行性。依據Schofiled’s model所撰寫的模擬程式配合特定紐賽數關係式(Nusselt number correlation)其單層疏水預測結果與實驗誤差最大約18.93%，平均誤差約7.16%。疊合膜預測結果與實驗誤差最大約22.79%，平均誤差約10.25%。

關鍵字

直接接觸薄膜蒸餾法 ； 疏水/親水複合膜 ； 疏水/親水疊合膜 ； 紐賽數關係式 ； 數值模擬

並列摘要

In recent years, many countries have made a lot of efforts to develop sea water desalination technology for the growing demand of water. At the same time, the usage of low grade waste heat and renewable energy is paid more attention because of the global warming issues and the growing prices of fossil fuels. Therefore, the membrane distillation, which is a desalination technology used with low grade waste heat or renewable energy, is more attractive now. This thesis investigates the heat and mass transport phenomena of direct membrane distillation (DCMD), which is one of varied membrane distillation methods.
In this thesis, we develop the computer programs of Fortran to simulate the operation of DCMD within single hydrophobic membranes, or within composite membranes, and then compare the simulation results with other researchers’ work. The deviations of numerical results from experimental data for single hydrophobic membranes are below 18.93% (maximum error), and 7.16% in average. For stacked membranes, the deviations are 22.79% in maximum, and 10.25% in average.

參考文獻

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