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研究生:高啟綜
研究生(外文):Gau, Chii-Tzong
論文名稱:氣-液兩相掃流薄膜超過濾之研究
論文名稱(外文):A Study on Gas-Liquid Two-Phase Cross-Flow Membrane Ultrafiltration
指導教授:鄭東文
指導教授(外文):Cheng Tung-Wen
學位類別:碩士
校院名稱:淡江大學
系所名稱:化學工程學系
學門:工程學門
學類:化學工程學類
論文種類:學術論文
論文出版年:1996
畢業學年度:84
語文別:中文
論文頁數:164
中文關鍵詞:濾速薄膜超過濾兩相阻力串聯模式邊界層理論模式
外文關鍵詞:Permeate fluxMembraneUltrafiltrationTwo-phaseResistance-in-series modelBoundary-layer theory model
相關次數:
  • 被引用被引用:4
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本論文以探討薄膜超過濾程序之濾速行為為目標,提出濾速之預測模式,
並對氣-液兩相掃流薄膜超過濾系統之濾速提升做一系列之分析。實驗中
使用之薄膜模組有中空纖維型及管型兩種,其薄膜材質分別為
polysulfone及Ziconia/Carbon,測試溶液為dextran T500之水溶液。濾
速預測模式方面,首先以阻力串聯模式分析實驗所得傳統(單相流動)掃流
薄膜超過濾之濾速實驗數據,得知各實驗系統中,各項阻力與操作參數間
之關係,進而獲得其濾速實驗公式。另由邊界層積分公式,配合滲透壓模
式,推導得出一邊界層理論模式,用以預測傳統掃流薄膜超過濾之濾速,
此濾速預測值與實驗值比較,趨勢上一致,但定量上理論值偏低,其原因
可能是一些假設不盡理想所引起,如:濃度分佈式、濾速假設式及不考慮
邊界層內濃度對擴散係數的影響等。在本氣-液兩相掃流薄膜超過濾系統
,其氣-液兩相流動形態皆屬於塊狀流動,發現氣體導入於掃流流束中,
可擾亂濃度邊界層,減輕濃度極化現象,促使濾速提升,提升比最高可
達196%。在液體流動屬層流區時,通氣對濾速之提升比愈加明顯,其次為
過渡區及紊流區。在過渡區及紊流區時,通氣對濾速之提升比,隨透膜壓
差與進料濃度之增加及液相掃流速度之降低而呈規律地增加,即當濃度極
化現象愈嚴重時,氣-液兩相掃流薄膜超過濾法,愈能發揮其功效。

The behaviors of permeate flux for dextran T500 solution in a
cross-flow membrane ultrafiltration process have been
investigated where the permeate flux models for liquid phase
ultrafiltration system were developed and the flux for the gas-
liquid two-phase ultrafiltration system were analyzed. Two types
of membrane module were used in the experimental work. These
included hollow-fiber module and tubular module with membrane
materials of polysulfone and Ziconia/Carbon, respectively.The
data of experimental flux were first analyzed by using
resistance-in-series model to obtain the relationships between
the resistance and the operating parameter, and then an
empirical equation for predicting permeate flux was found. A
boundary layer theory model was also proposed, which was derived
from the integral equation of concentration boundary layer in
association with the osmotic pressure model. The permeate flux
calculated from the model were lower than the experimental data.
This deviation may be due to some unsuitable assumptions, such
us concentration profile, permeate flux profile, and constant
diffusivity.In the analysis of the permeate flux in a gas-liquid
two-phase ultrafiltration system, introduction of gas slugs into
the cross-flow stream may disturb the concentration boundary
layer and reduce the concentration polarization, leading to an
enhancement of the ultrafiltration permeate flux. The permeate
flux enhanced by the gas slugs was up to 196% in this
experimental work. The enhancement was significant when the
cross-flow system was operated in the laminar regime, and then
in transition regime and turbulent regime. The flux enhancement
ratios in transition regime and turbulent regime increase with
the increasing in transmembrane pressure and inlet
concentration, and with the decreasing in liquid velocity.

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