Effect of bubble flow velocity on drag-force and shear stress working on submerged hollow fibre membrane

2006 ◽  
Vol 54 (10) ◽  
pp. 185-192 ◽  
Author(s):  
H. Nagaoka ◽  
M. Kurosaka ◽  
N. Shibata ◽  
M. Kobayashi
Keyword(s):  
Shear Stress ◽  
Drag Force ◽  
Membrane Surface ◽  
Hollow Fibre ◽  
Laser Doppler Velocimeter ◽  
Bubble Flow ◽  
Hollow Fibre Membrane ◽  
Membrane Surfaces ◽  
Fibre Membrane ◽  
Upward Direction

This study is aimed at elucidating the mechanism by which rising air bubbles induce shear stress on hollow fibre membrane surfaces. Shear stress on hollow fibre membrane surfaces (laterally-set and vertically-set) caused by aeration was measured directly using a two-direction load sensor. In the laterally-set hollow fibre module, time-averaged upward-direction shear stress on the membrane surface was compared to theoretical shear stress values considering the effect of water flow on membrane surface. Measured time-average shear stress values were almost 200 times larger than theoretical values implying strong interactions between bubbles and solid surface. In the vertically-set membrane module, velocity measurement of bubble flow using laser Doppler velocimeter revealed that drag force working on membrane surface was closely related to upward-direction water velocity. Also fluctuation of drag force and shear force on membrane surface was found to be related to velocity fluctuation (turbulence).

PVDF-TiO2 Hollow Fibre Membrane For Water Desalination

2021 ◽  
Vol 12 (1) ◽  
pp. 1-6
Author(s):  
Muthia Elma ◽  
Mahmud Mahmud ◽  
Nurul Huda ◽  
Zaini L Assyaifi ◽  
Elsa Nadia Pratiwi ◽  
...  
Keyword(s):  
Sea Water ◽  
Hollow Fiber Membrane ◽  
Membrane Surface ◽  
Hollow Fibre ◽  
Water Desalination ◽  
Hollow Fibre Membrane ◽  
Fibre Membrane ◽  
Dope Solution ◽  
Feed Temperature ◽  
Process Method

The clean water crisis is increasing along with the increasing human population. Sea water is one of the largest water sources that can be utilized on the earth. However, the high salt concentration dissolved in seawater must be treated before it can use. Desalination is the directly technology for treating seawater with PVDF-TiO2 hollow fibre membrane via pervaporation process. The aim of this research was to determine the performance of PVDF-TiO2 hollow fibre membrane against variations in feed temperature in the artificial seawater pervaporation process. Method for fabrication membrane is using dry-wet spinning method. The result showed that the highest flux permeat occurred at feed temperature of 60ºC, namely 8.96 kg.m-2.h-1 with salt rejection > 92.86%. The result via SEM showed that of the membrane surface morphology, there is a white spot on the membrane surface is TiO2 because the dope solution is too thick. The PVDF-TiO2 hollow fiber membrane in this research is can be applied for seawater pervaporation.

Application of hollow fibre membrane reactor for biological removal of H2S

2020 ◽  
Author(s):  
Jewel Das ◽  
Harish Ravishankar ◽  
Piet Lens
Keyword(s):  
Mass Transfer ◽  
Membrane Surface ◽  
Hollow Fibre ◽  
Microbial Community Analysis ◽  
Rayon Production ◽  
Membrane Area ◽  
Hollow Fibre Membrane ◽  
Fibre Membrane ◽  
Physico Chemical ◽  
Biological Methods

<p>Hydrogen sulfide (H<sub>2</sub>S) is a toxic pollutant and harmful to human health. Industries such as pulp and paper manufacturing, rayon production, natural gas extraction and refining, and crude petroleum refineries generate waste gas streams with high H<sub>2</sub>S concentrations. Both physico-chemical and biological methods are used for H<sub>2</sub>S removal from the gas stream. Biological methods offer several advantages such as environmental friendly, less expensive and require simple operation and maintenance compared to physico-chemical methods. In this study, a hydrophilic hollow fibre membrane (HFM) based bioreactor configuration has been tested for biological H<sub>2</sub>S removal. Three reactors were fabricated and operated for ~ 3 months where two reactors were used for biological conversion process and the third reactor was used for abiotic process. The effective membrane area of a HFM module used in each reactor was 0.0138 m<sup>2</sup>. The bioreactors demonstrated efficient gas-liquid mass transfer through the HFM module and achieved ~ 99% removal efficiency with an elimination capacity of ~ 17.0 g m<sup>-3</sup> h<sup>-1</sup>. The H<sub>2</sub>S flux of the bioreactor was ~ 0.20 g m<sup>-2</sup> day<sup>-1</sup> which was ~ 9 times higher than the abiotic reactor for an inlet H<sub>2</sub>S concentration of ~ 0.90 g m<sup>-3</sup>. The overall mass transfer coefficient value for the biotic process was 17.2 µm s<sup>-1</sup> which was ~ 25 times higher than the abiotic process. The bioreactors demonstrated both microbial attached growth on the membrane surface and suspended growth in the liquid phase. Microbial community analysis confirmed the presence of diverse sulfur-oxidizing bacteria at genus level including <em>Acinetobacter</em>, <em>Dechloromonas</em>, <em>Hydrogenophaga</em>, <em>Rhodopseudomonas</em> and <em>Sulfurospirillum</em>. Moreover, the enrichment of other bacterial genera such as ammonia-oxidizing (e.g. <em>Nitrosospira</em>), organic matter degrading (e.g. <em>Trichococcus</em>) and methanogenic (e.g. <em>Methanosaeta</em>) microorganisms demonstrate the diverse microbial ecology of the sludge growing in the bioreactor.</p>

Experimental evaluation of the Dideco D903 Avant 1.7 hollow-fibre membrane oxygenator

Perfusion ◽  
1998 ◽  
Vol 13 (5) ◽  
pp. 353-359 ◽  
Author(s):  
Xavier M Mueller ◽  
Hendrick T Tevaearai ◽  
Monique Augstburger ◽  
Judith Horisberger ◽  
L K von Segesser
Keyword(s):  
Pressure Drop ◽  
Membrane Surface ◽  
Blood Gas Analysis ◽  
Hollow Fibre ◽  
Gas Analysis ◽  
Arterial Oxygen ◽  
Blood Gas ◽  
Membrane Oxygenator ◽  
Hollow Fibre Membrane ◽  
Fibre Membrane

Membrane oxygenators have now gained wide acceptance. A new hollow-fibre membrane oxygenator, the Dideco D903 Avant 1.7, with an optimized membrane surface (1.7 m2) and a wavy blood flow pattern, was tested for gas transfer and blood path resistance in a standardized setting with surviving animals. Three calves (mean body weight 63.29 ± 2.9 kg) were connected to cardiopulmonary bypass by jugular venous and carotid arterial cannulation, classic roller pump and the Dideco D903 oxygenator with a mean flow rate of 53 ± 0.1 ml/kg/min for 6 h. After this time, the animals were weaned from the CPB and thereafter from the ventilator. After 7 days, the animals were killed electively. Blood gas analysis was performed before bypass, after mixing (10 min) and then hourly for the 6 h of perfusion. Further samples were taken 30 min (spontaneous breathing) and 60 min after bypass (extubated). Physiological blood gas values could be maintained throughout perfusion in all animals. Mean arterial oxygen saturation varied between 99.3% and 99.7% for the arterial side of the oxygenator compared to 64.6% and 71% for the venous side. The highest mean pressure drop through the oxygenator was 54 mmHg. Postbypass blood gas analysis showed physiological values and no evidence of major lung trauma or pulmonary oedema in relation to the 6 h perfusion. The hollow-fibre membrane oxygenator, Dideco D903, offers excellent gas exchange capabilities and a low pressure drop under experimental conditions, despite reduced membrane surface area. The post mortem examination did not show any deleterious lesion.

scholarly journals Fabrication and characterization of composite hollow fibre membrane derived from hydroxyapatite cow bone and kaolin

2021 ◽  
Vol 1142 (1) ◽  
pp. 012011
Author(s):  
Suraya Najieha Kamarudin ◽  
Mohd Riduan Jamalludin ◽  
Siti Nor Suhaida Rasman ◽  
Siti Khadijah Hubadillah ◽  
Mohd Arif Budiman Pauzan ◽  
...  
Keyword(s):  
Hollow Fibre ◽  
Hollow Fibre Membrane ◽  
Fibre Membrane ◽  
Fabrication And Characterization ◽  
Cow Bone
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