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    題名: 通入氣泡以提升掃流微過濾之效能
    其他題名: Efficiency enhancement in cross-flow microfiltration by air-bubble injection
    作者: 吳雅茹;Wu, Ya-ju
    貢獻者: 淡江大學化學工程與材料工程學系碩士班
    黃國楨;Hwang, Kuo-jen
    關鍵詞: 掃流微過濾;多相流動;過濾效能;cross-flow microfiltration;multiphase flow;filtration efficiency
    日期: 2006
    上傳時間: 2010-01-11 05:37:29 (UTC+8)
    摘要: 本研究探討於掃流微過濾裝置中通入氣體對過濾效能之提升,並探討操作條件對多相流(固、液、氣三相)掃流微過濾之濾速與濾餅性質之影響。實驗中使用平均孔徑為0.1μm的醋酸纖維膜(Mixed cellulose ester) 過濾平均粒徑為0.4μm之聚甲基丙烯酸甲酯(PMMA)粒子,故粒子只能附著於薄膜表面,形成濾餅層。在多相流之微過濾實驗中,改變通入之氣體流量、過濾壓差、液體速度、進料濃度等變因,量測其對於濾速,濾餅量與過濾阻力之變化。實驗結果顯示,多相流之過濾程序中濾餅之成長是可逆的,濾餅量與濾速取決於最終之操作條件。當通氣量越大時,穩定濾速會越高,但提昇之效率仍然有其最終極限。經改變各種操作變因,都發現平均過濾比阻值並無顯著的變化,故濾餅成長量為影響過濾速度的最主要因素,而濾餅成長量可以由本研究提出之模式估計。在本研究之操作條件範圍內,氣體速度為0.12 m/s之濾速為無通氣時的2倍;液體速度或過濾壓差提高5倍皆可提升濾速1.5倍;但是懸浮液濃度增加5倍後,濾速僅為原來的1/3。總而言之,通入氣泡可以有效提升掃流微過濾之效能。
    The efficiency enhancement in cross-flow microfiltration of submicron particles by air-bubble injection is studied. The effects of operating conditions, such as flow rates of suspension and air, filtration pressure and suspension concentration, etc., on the cake properties and filtration rate are also discussed. A filter membrane, made of mixed cellulose ester, with a mean pore size of 0.1mm is used to filter 0.4 mm PMMA particles; therefore, particles may be deposited on the membrane surface to form a filter cake. The results show that the cake formation in multiphase filtration process is reversible, and the pseudo-steady filtration rate increases with increasing air-bubble flow rate. However, the increase in filtration rate is more significant under lower air-bubble flow rate. Since the average specific filtration resistance of cake varies slightly within the operating conditions of this study, the cake mass plays the major role in determining filtration resistance and filtration rate. The cake mass can be related to the ratio of wall shear stress to filtration rate based on the proposed model. The filtration rate at the gas velocity of 0.12 m/s is double compared to that in the case of no air injection. The filtration rate is 1.5-fold when liquid velocity increases from 0.1 to 0.5 m/s or filtration pressure increases from 20 to 100 kPa. However, the filtration rate becomes 1/3 when PMMA concentration increases from 0.1 to 0.5wt%. In general, the injection of air-bubble can significantly enhance filtration efficiency in cross-flow microfiltration of fine particles.
    顯示於類別:[化學工程與材料工程學系暨研究所] 學位論文

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