近年石化能源漸漸枯竭，尋找替代能源以成為主要的課題，而生質乙醇為替代能源之一。本研究利用空氣式薄膜蒸餾法(AGMD)應用於乙醇連續發酵系統中，探討AGMD所適用的膜材、溫度、進料流速對於通量及乙醇選擇性的影響。亦討葡糖糖發酵條件，以最佳的條件測試乙醇連續發酵。
研究結果顯示：空氣間隙式薄膜蒸餾，測試膜材中以PTFE0.02 mm含不織布膜對乙醇水溶液分離效果為最佳，薄膜厚度亦會影響通量與選擇性，隨著薄膜厚度增加，通量會隨之減少，選擇性則會隨之而提升。AGMD的操作溫度會影響所得到的通量以及乙醇的選擇性，通量與選擇性會隨著溫度差增加而提高。進料端流速亦會影響到AGMD的通量，隨著進料流速增加而提高。利用AGMD進行發酵液乙醇分離，通量不會受到發酵液中酵母菌等其他因素影響，選擇性則可將發酵液中乙醇濃度提升288%。
乙醇發酵；葡萄糖濃度為20wt%並添加1wt%的無磷培養基，pH控制於4~5之間，於30℃發酵槽中以350 rpm攪拌速度進行發酵，發酵五天後經陶瓷膜過濾抽取1/2發酵液，進行AGMD乙醇分離，並添補葡萄糖溶液進行連續發酵。研究共添加兩次葡萄糖溶液，三次的批次發酵，添加葡萄糖溶液後，發酵液乙醇濃度皆可回升至10v%以上，亦可證實連續發酵的可行性。 Membrane distillation (MD) is a relatively new separation process which is being investigated worldwide as a low cost, energy saving alternative to other conventional separation processes. The major aim of this proposal is that the bioethanol produced from fermentation via the membrane distillation system through the expanded polytetrafluoroethylene (ePTFE) membranes. Hopefully, a high flux of MD membrane and ethanol separated from the reaction mixtures can be obtained in this program. We aim to concentrate and purify ethanol through the membranes from simulate fermentation system, and establish a continuous MD system for separate and purify bioethanol from fermentor.
Moreover in the energy conservation, this research discusses the effect of little temperature difference. In addition, the effects of temperature and pressure gradient of the MD system and the air-gap distance on the ethanol purify performance will be investigated.
