Modelling of optimal back-shock frequency in hollow-fibre ultrafiltration membranes II: Semi-analytical mathematical model

详细信息    查看全文

• 作者：Frank Vinther ^{frank.vinther@chemeng.lth.se" class="auth_mail" title="E-mail the corresponding author} ; Ann-Sofi Jö ; nsson ; ^{ann-sofi.jonsson@chemeng.lth.se" class="auth_mail" title="E-mail the corresponding author}
• 关键词：Back-shocking ; Mathematical modelling ; Semi-analytical model ; Ultrafiltration ; Net flux ; Back-shock frequency
• 刊名：Journal of Membrane Science
• 出版年：2016
• 出版时间：15 May 2016
• 年：2016
• 卷：506
• 期：Complete
• 页码：137-143
• 全文大小：1577 K

文摘

The influence of cross-flow velocity and transmembrane pressure on the optimal back-shock frequency and normalized net flux during back-shocking has been studied using a semi-analytical mathematical model. The model uses the flux as a function of time without back-shocking together with knowledge of the streamlines and pathlines during the back-shock cycle to predict the optimal normalized net flux as a function of forward filtration time.

The model was used to investigate three different transmembrane pressures and three different cross-flow velocities during a back-shock cycle. The net flux was found to increase under all operating conditions when using back-shocking. The greatest increase in normalized net flux was found at the highest cross-flow velocity and the highest transmembrane pressure, and corresponds to an increase of 37% compared to the steady-state flux. The highest cross-flow velocity and the highest transmembrane pressure gave the highest optimal back-shock frequency of 0.21 Hz. The optimal back-shock frequency was found to decrease with increasing pressure and decreasing cross-flow velocity.

The model is easy to use in different applications as it is easy to measure flux during forward filtration without back-shocking. Good agreement was found between the semi-analytical model and a model based on computer fluid dynamics in predicting both the value of the optimal normalized net flux and the optimal back-shock frequency.