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    Title: 沉浸式薄膜過濾中粒子附著機構之研究
    Other Titles: A study on the mechanism of particle deposition in submerged membrane filtration
    Authors: 陳祥嘉;Chen, Hsiang-chia
    Contributors: 淡江大學化學工程與材料工程學系碩士班
    黃國楨;Hwang, Kuo-jen
    Keywords: 沉浸式薄膜過濾;微過濾;附著機率;粒徑分佈;submerged membrane filtration;microfiltration;Particle deposition;Particle size distribution
    Date: 2008
    Issue Date: 2010-01-11 05:40:51 (UTC+8)
    Abstract: 本研究在討論操作條件對沉浸式薄膜過濾之粒子附著機構的影響。以孔洞大小為0.1μm之薄膜,過濾平均粒徑為7μm之聚甲基丙烯酸甲酯(PMMA)粒子,探討不同的過濾通量、過濾時間、通入空氣之曝氣量與氣泡大小等操作條件對粒子的附著機構與過濾效能之影響。
    研究結果顯示:針對次微米粒子而言,粒子間的作用力是影響粒子附著的主要作用力,隨著粒徑的提升,粒子間的作用力之影響便逐漸減小,轉而由切線方向的作用力來主導。當過濾時間達3600秒時,最終壓力與濾餅便以達到一擬穩定值,且當過濾通量三倍,最終壓力提高了近5倍,而濾餅量則增加約7倍的量。根據實驗所得之數據可知,粒子的附著可依據其分佈的不同而做區分,當粒徑在1μm以下時,粒子間的附著會受到粒子間作用力的影響,隨著粒徑的增加而變小,但是當粒徑大於1μm後,粒子間的作用力之影響便不在顯著,使得其機率逐漸上升,但隨著粒子的增大,切線方向的作用力也隨之加大,使得附著機率逐漸開始下降,而當粒徑大過10μm之後,粒子便不易附著,而粒子的附著會隨著操作條件的不同而有所改變。通入氣泡除了有助於掃除濾餅之外,還能使小粒子易於附著,且通氣量越大,此現象就越為明顯,且經比較之後發現,改變氣泡大小的效果比通氣量來得大;而加入通氣會膜面的穩定性減小,進而導致粒子不易附著,使其附著機率下降,且當粒徑越大,此現象就越為顯著。理論所計算出來的濾餅性質與實驗所求得之濾餅性質相比,仍須將理論計算的部份加以修正,如此方能使其符合實驗值。
    The effects of operated conditions, such as filtration flux, filtration time, particle size, aeration intensity, air bubble size on the deposition properties, cake properties, and the performance in submerged membrane filtration are studied. A particulate sample with a wide size distribution range from submicron to micron is used in experiments. The properties of particle deposition are analyzed based on a force analysis. The results show that: For submicron particle, the interparticle force plays a major role in particle deposition, however, the drag force, gravitational force and bubble shear force increase their importance as particle increase. When particle size is larger than 1μm, the interparticle force drops rapidly, i.e. the van der Waals force is greater than electrostatic force under these conditions. Therefore, the importance forces that effect particle deposition include drag force, gravitational force and bubble shear force as particle size larger than 10μm. Increasing filtration flux lead to enlarge normal drag force and increase deposition properties. An increase in aeration intensity and reduction of bubble size can also decrease particle deposition properties. Furthermore, the cake properties, such as mass, porosity and average specific filtration resistance of cake would be affected by deposition properties. Although some theoretical cake properties are closed to experimental data, but the probability of particle deposition functions still need to modify.
    Appears in Collections:[化學工程與材料工程學系暨研究所] 學位論文

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