本研究旨在研究生物懸浮液的通氣掃流微過濾之影響，並探討對操作條件對，例如氣體之流量、過濾壓差、液體速度，濾速、濾餅性質及濾面上剪切力之影響。實驗中使用平均孔徑為0.1μm的醋酸纖維膜過濾平均粒徑為4.7μm之酵母菌粒子。實驗結果顯示，隨通氣量越大時，作用於濾面上剪切力也越大，濾餅量顯著減少，但是也會導致濾餅平均過濾比阻增加；綜合濾餅量與過濾比阻兩個因素，濾餅阻力會隨著通氣量之增加而增加，導致濾速下降。故平均過濾比阻是影響濾速與過濾阻力的主要因素。掃流速度越快對擬穩定率速能夠提升，但超過0.3m/s反而會下降。過濾壓差增加並不能對穩定濾速有顯著的提昇。本研究並利用多相流理論算出膜面上剪切力，並與實驗值比較，發現理論值需要經由修正才能符合實驗結果。而氣體流量對該修正因子之影響較小，液體速度則影響較大，因此將修正係數與液體速度回歸成一個關係式。

The gas-sparging cross-flow microfiltration of bio-suspension is studied. The effects of operating conditions, such as liquid velocity, gas velocity and filtration pressure, on the filtration rate, cake properties, shear stress acting on the membrane surface are discussed. A filter membrane made of mixed cellulose ester with a mean pore size of 0.1μm is used for filtering 4.7μm yeast cells . An increase in gas flow rate leads the shear stress on the membrane surface and the average specific filtration resistance of cake to increase ,but  the cake mass to decrease. To take these factors into consideration, the overall filtration resistance is increased and the filtration rate is decreased with the increasing the flow rate of sparging gas. In addition ,the filtration rate increases with the increase of liquid velocity under low velocity range. When liquid velocity exceeds 0.3 m/s, a contrary tendency is obtained. This is because the cake structure becomes more compact. Since the average specific filtration resistance of cake plays the major role in determining filtration resistance to operate under low liquid velocity range can enhance the filtration rate .Comparing the data of shear stress estimated by theory and measured in experiments, a correction factor should be taken into account.

目 錄
頁次
中文摘要		Ⅰ
英文摘要		Ⅱ
目 錄		IV
圖表目錄		VIII
	
第一章 緒論		1
第二章 文獻回顧		  6
	2-1掃流過濾特性		6
	2-2過濾程序中通入氣體之影響的特性		12
第三章 理論		21
	3-1掃流過濾模組內之力分析		21
	3-2粒子在掃流過濾時之受力情況		22
	3-3粒子在濾面上之附著機構		33
	3-4濾餅的過濾比阻、孔隙度和固體壓縮壓力的關係		35
	3-5掃流微過濾之模式探討		35
第四章 實驗裝置與步驟		37
	4-1 掃流過濾實驗裝置、物料與濾膜		37
	4-2分析儀器		39
	4-3分析軟體		39
	4-4實驗步驟		40
	4-5薄膜前後壓差之測量方法		42
第五章 實驗結果與討論		43
	5-1氣體量對掃流微過濾的影響		46
	5-2通氣過濾對濾餅性質的影響		49
	5-3過濾壓差對多相流動過濾的影響		59
	5-4多相流動中濾餅成長機構		64
	5-5多相流動中之流態觀察		68
	5-6多相流中剪切力之變化		77
第六章 結論		84
符號說明		86
參考文獻		90
附錄		94
	附錄A 實驗物料的種類及物性		94
	附錄B 實驗數據計算式		97
	附錄C 氣泡大小之量測		99
	附錄D 剪切力的計算		101

圖表目錄
頁次
圖目錄
第一章
Fig.1-1 Separation spectrum under different particle sizes	2
Fig.1-2.Schematics of dead-end filtration and cross-flow filtration	3
Fig.1-3 Typical Methods to reduce concentration polarization and fouling in pressure driven membrane processes	4
第二章
Fig. 2-1 shear stress number and resistance number plot1	6
Fig. 2-2 Two-phase flow pattern inside pipes( Cabassud et al.2001)	18
第三章
Fig.3-1 Schematics of momentum balance for a rectangular element in cross-flow filtration system	21
Fig.3-2 Force exerted on a depositing particle in the cross-flow system	23
Fig.3-3 Interaction energy of Van der Walls force and electrical double layer repulsive force under different distance	27

Fig.3-4 Separated horizontal flow model. Simultaneous gas/liquid flow in (a) is considered as the combination of gas and liquid flow，as(b) and (c).
	30
Fig.3-5 Force exerted on a depositing particle	34
第四章
Fig.4-1 A schematic diagram of flow direction	37
Fig.4-2 A schematic diagram of cross-flow filtration system	38
第五章
Fig.5-1 Decay of filtration rates during cross-flow microfiltration under various aeration condition	44
Fig.5-2 Comparison of the pseudo steady state filtration rates during cross-flow microfiltration under various aeration condition at UL=0.3m/s and UL=0.1m/s	45
Fig.5-3 Comparison of cake mass during cross-flow microfiltration under various aeration condition at UL=0.3m/s and UL=0.1m/s	49
Fig.5-4 Comparison of the average specific filtration resistance during cross-flow microfiltration under various aeration condition at UL=0.3m/s and UL=0.1m/s	50
Fig.5-5 The top view of membrane surface after filtration experiment (Ug=0.02 Ul=0.3m/s ΔP=50kPa)(5000X) 	51
Fig.5-6 The top view of membrane surface after filtration experiment (Ug=0.04 Ul=0.3m/s ΔP=50kPa)(5000X) 	51
Fig.5-7 The side view of membrane surface after filtration experiment (UG=0m/s UL=0.1m/s ΔP=50kPa)(5000X)	 52
Fig.5-8 The side view of membrane surface after filtration experiment (UG=0.02m/s UL=0.1m/s ΔP=50kPa)(5000X) 	52

Fig.5-9 Comparison of shear stress during cross-flow microfiltration under various aeration condition at UL=0.3m/s and UL=0.1m/s	53
Fig.5-10 Comparison of the pseudo steady state filtration rates during cross-flow microfiltration under different liquid velocities	54
Fig.5-11 Comparison of the cake resistances at the pseudo steady-state under different liquid velocities	55
Fig.5-12 Comparison of the cake mass at the pseudo steady-state under different liquid velocities	56
Fig.5-13 Comparison of the shear stress different liquid velocities(UL=0.1m/s~0.5m/s)andUG=0.08m/s	57
Fig.5-14 Comparison of the average specific filtration resistances at the pseudo steady-state under different liquid velocities	58
Fig.5-15 Comparison of the pseudo steady-state under different filtration pressure	60
Fig.5-16 Comparison of the cake resistances at the pseudo steady-state under different filtration pressure	61
Fig.5-17Comparison of the average specific filtration resistances at the pseudo steady-state under different filtration pressure	62
Fig.5-18Comparison of the cake mass at the pseudo steady-state under different filtration pressure	63
Fig.5-19 A plot of Rt v.s. τ	65
Fig.5-20A plot of cake mass v.s.τ	66
Fig.5-21 A plot of the average specific filtration resistances v.s. τ	67
Fig.5-22 Image of bubble under different gas velocities and UL=0.1m/s (a)UG=0.02m/s (b) UG=0.04m/s (c) UG=0.08m/s	69
Fig 5-23Image of bubble under different gas velocities and UL=0.3m/s (a)UG=0.02m/s (b) UG=0.04m/s (c) UG=0.08m/s	70
Fig.5-24 Image of bubble under different gas velocities and UL=0.5m/s (a)UG=0.02m/s (b) UG=0.04m/s (c) UG=0.08m/s	71
Fig 5-25Bubble frequency distribution under UL=0.1m/s and  UG=0.02m/s ~ UG=0.08m/s	72
Fig 5-26 Bubble frequency distribution under UL=0.3m/s and  UG=0.02m/s ~ UG=0.08m/s	73
Fig 5-27 Bubble frequency distribution under UL=0.5m/s and  UG=0.02m/s ~ UG=0.08m/s	74
Fig 5-28 Bubble frequency distribution under UG=0.08 m/s and  UL=0.1m/s ~ UL=0.5m/s	75
Fig 5-29 mean bubble diameter under different operation condition	76
Fig 5-28A plot of true liquid velocity v.s gas superficial gas velocity	78
Fig 5-29 A plot of true gas velocity v.s gas superficial gas velocity	79
Fig 5-30 Fig 5-30 A plot of shear stress v.s liquid velocity	80
Fig 5-31 A plot shear stress (experimental value)v.s gas superficial velocitiy	81
Fig 5-32 Correlation factor under different liquid velocities and gas velocities	82
Fig 5-33 Correlation factor under different liquid velocities	83
附錄
Fig. A-1 The SEM picture of yeast（20,000X）	95
Fig. A-2 Particle size distribution of Yeast under pH=7.0	95
Fig.A-2.1 The top view of the mixed cellulose ester membrane by SEM(30000X)	96
Fig.C-1 The bubble of image	99
Fig.C-2 The bubble size distribution	100
表目錄
Table 3-1 Values from Lockhart and Martinelli (James O. Wilkes 1999)	32
Table.3-2 Exponent for Two-Phase Correlation (James O. Wilkes 1999) 	33
Table 4-1 The operating conditions used in this study	42
Table C-1 Calculated Bubble size distribution	99
Table D-1 calculated shear stress	101

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