薄膜蒸餾(membrane distillation, MD)是利用多孔性疏水薄膜，在薄膜兩側提供溫度之差異，藉以因水蒸氣壓差產生水之傳輸，可應用於水之純化或水溶液之濃縮。針對真空式薄膜蒸餾，本論文探討之物質系統包括純水、鹽水與葡萄糖水溶液，亦即脫鹽與水溶液濃縮應用，利用兩種商業化中空式纖維模組，進行了不同操作條件之實驗，並建立數學模式探討不同操作條件之影響。實驗與模擬結果相當接近。藉由模式也分析模組內熱質傳阻力之重要性。 考量薄膜蒸餾操作需要具溫差之冷熱物流，以及熱泵可同時提供熱能與冷能之特性，本論文提出薄膜蒸餾與熱泵之熱能整合設計，包括氣隔式薄膜蒸餾與熱泵，以及氣隔式加真空式薄膜蒸餾與熱泵兩種流程。流程設計中利用超結構之概念，納入可能之分流架構。吾人利用在Aspen Custom ModelerÒ平台自行建立之數學模式，進行流程內架構變數與操作變數之最佳化分析。針對海水脫鹽與葡萄糖水溶液濃縮之應用，最佳化結果顯示氣隔式薄膜蒸餾與熱泵設計之性能表現優於氣隔式加真空式薄膜蒸餾與熱泵設計。 Membrane distillation (MD) allows the transfer of water vapor across a porous hydrophobic membrane by providing temperature difference on both sides of the the membrane. MD can be applied for water purification or solution concentration. For the vacuum membrane distillation (VMD), this thesis experimentally investigates pure water, salt water and glucose aqueous solution, in other words, for the applications of desalination and solution concentration, using two types of commercial hollow fiber type membrane distillation modules. A mathematical model is developed for VMD. Experimental and simulation results are very close. The effects of operating conditions are studied by experiments and the model. The significance of the heat and mass transfer resistances inside the modules have been analyzed using the model. Given that MD requires hot and cold fluids and heat pump can provide hot and cold energies, this thesis proposes the integrated systems of MD and heat pump. Two flowsheets investigated are the air gap MD (AGMD)-heat pump and AGMD+VMD-heat pump. The superstructure concept is employed for developing the configurations, i.e. the split flow alternatives, of the two flowsheets. Using the mathematical models developed on Aspen Custom ModelerÒ platform, the configuration and operating variables are optimized. For both desalination and glucose aqueous solution concentration applications, the performance of AGMD-heat pump flowsheet is better than AGMD+VMD-heat pump flowsheet.
