Numerical Simulation of Filtration of Charged Oil Particles in Stationary and Rotating Tubular Membranes

2015 ◽  
Author(s):  
Sina Jahangiri Mamouri ◽  
Volodymyr V. Tarabara ◽  
André Bénard
Keyword(s):  
Flow Field ◽  
Electric Field ◽  
Electric Potential ◽  
Membrane Fouling ◽  
Membrane Surface ◽  
Cross Flow ◽  
Solid Cylinder ◽  
Permeate Flux ◽  
Cross Flow Filtration ◽  
Flow Filtration

Cross flow filtration (CFF) is a common membrane separation process with applications in food, biochemical and petroleum industries. In particular, membranes can be used for liquid-liquid separation processes such as needed in oil-water separation. A major challenge in cross flow filtration is membrane fouling. It can decrease significantly the permeate flux and a membrane’s efficiency. Membrane fouling can be mitigated by inducing shear on the membrane’s surface and this can be enhanced by inducing a swirl in the flow. In addition, a possible approach to improve membrane efficiency consists of repelling droplets/particles from the porous surface toward the centerline using a repulsive electric force. For this purpose, the surface of the membrane can be exposed to electric potential and droplets/particles are also induced to have the same electric charge. In this work, numerical simulations of charged non-deformable droplets moving within an axially rotating charged tubular membrane are performed. The results show that by increasing the electric potential on the membrane surface, the repelling force increases which obviously improves the grade efficiency of the membrane. However, the electric field gradients found in the flow field require large potentials on the membrane surface to observe a noticeable effect. Hence, a smaller solid cylinder is located in the centerline of the flow channel with zero potential. This solid cylinder enhances the electric field gradient in the domain which results in higher repelling forces and larger grade efficiency of the membrane at small potentials. The addition of a small cylinder in the flow field also improves the grade efficiency increases due to the higher shear stress near the membrane surface.

Gas sparged cross-flow microfiltration of biologically treated wastewater

2000 ◽  
Vol 41 (10-11) ◽  
pp. 173-180 ◽  
Author(s):  
L. Vera ◽  
S. Delgado ◽  
S. Elmaleh
Keyword(s):  
Shear Stress ◽  
Membrane Fouling ◽  
Cross Flow ◽  
Solid Content ◽  
Treated Wastewater ◽  
Inorganic Membrane ◽  
Form Complex ◽  
Cross Flow Filtration ◽  
Mass Transport Process ◽  
Flow Filtration

A novel technique was tested for reducing tubular mineral membrane fouling by injecting gas into a cross-flow stream. The injected gas is thought to form complex hydrodynamic conditions inside the microfiltration module, which increase the wall shear stress, preventing the membrane fouling and enhancing the microfiltration mass transfer. The experimental study was carried out with biologically treated wastewater filtered through a tubular inorganic membrane (Carbosep M14). The flux, monotonously increasing with gas velocity, was more than tripled. New dimensionless quantities of shear stress number and resistance number were developed by generalisation of the dimensional analysis already carried out for the steady state flux of classical unsparged cross-flow filtration. A unique formalism allowed then interpreting the experimental results of both classical diphasic filtration and sparged filtration. The main limiting mass transport process was due to the solid content.

scholarly journals Microfiltration with periodic gas backwashing as an alternative technique for increasing permeate flux

2018 ◽  
Vol 72 (2) ◽  
pp. 59-68
Author(s):  
Tijana Urosevic ◽  
Dragan Povrenovic ◽  
Predrag Vukosavljevic ◽  
Ivan Urosevic
Keyword(s):  
Steady State ◽  
Flow Rate ◽  
Driving Force ◽  
Fruit Juice ◽  
Cross Flow ◽  
Fruit Juices ◽  
Transmembrane Pressure ◽  
Permeate Flux ◽  
Cross Flow Filtration ◽  
Flow Filtration

In this paper, the influence of operating parameters (transmembrane pressure, temperature, the flow rate of retentate) on the cross - flow microfiltration of synthetic fruit juice and periodic backwashing with air was examined. In the experiments, the Kerasep W5 ceramic membrane with a separation limit of 0.2 ?m was used. The results of experiments in which different transmembrane pressures were used showed that stationary fluxes, at stationary conditions, after 60 minutes, have similar values. So, it can be concluded that the value of the driving force is irrelevant at steady state conditions. However, until the steady state conditions are established, a positive effect of the increase in the driving force is opposed to the negative effect of the increased polarization resistance, as a result of the driving force increase. Thus, the optimal transmembrane pressure was determined amounting to 2 bars. The optimum temperature of the process of clearing the fruit juices by microfiltration is reported as 55?C. Higher temperatures are not used due to a degrading effect on the chemical composition of the juice and a long microfiltration process. With an increase in the temperature of retentate from 22?C to 55?C, the permeate flux increased up to 60%. Increasing the flow rate of retentate reduces the thickness of the formed layer on the surface of the membrane. Due to limitations of the experimental setup and the large surface area of the membrane, the specific velocity of the retentate was low, so that the effects of cross-flow filtration were absent. The use of cross-flow filtration is one of the main requirements for increasing permeate flux, but in the present case it was in overall insufficient, so we have applied periodic air backwashing for improving fruit juice flux during membrane clarification. With this technique, the deposited layer on the membrane is lifted and the permeate flux is maintained at high levels preventing establishment of the steady state in the low flux zone. The time spent for the periodic backwashing was low as compared to the benefits of the increase in the collected permeate quantity. In all experiments with periodic backwashing with air, the collected permeate quantity is higher for up to 72.5 % as compared to experiments without backwashing. By increasing the backwashing duration, the flux increase is up to 5 %, which can be significant for microfiltration at industrial scale. Therefore, this technique is certainly recommended for microfiltration in the production of fruit juices.

Ultrafiltration of Aqueous Solutions of Food Dye in the Presence of Surfactants

2017 ◽  
Vol 68 (1) ◽  
pp. 6-10
Author(s):  
George Alexandru Popa ◽  
Daniela Florentina Popa (Enache) ◽  
Dumitra Daniela Slave (Clej) ◽  
Ion Din Spiridon ◽  
Cristina Monica Mirea ◽  
...  
Keyword(s):  
Aqueous Solutions ◽  
Membrane Surface ◽  
Cross Flow ◽  
Sodium Octanoate ◽  
Food Dye ◽  
Cross Flow Filtration ◽  
Dead End ◽  
Food Dyes ◽  
Flow Filtration ◽  
Quinoline Yellow

The objective of the study is the low-pressure membrane process for treating aqueous solutions containing food dyes and surfactants. The influence of surfactants (SDS � sodium dedecil sulphate, SO � sodium octanoate) in the separation of synthetic food dyes (E104 � quinoline yellow) was analyzed. Polysulfone and polysulfone-polyaniline membranes were used. Dye and surfactant concentrations used were 10% (equivalent to 100g/m3). The pressures used in the ultrafiltration process were 0.1, 0.2 and 0.3 MPa. When dye containing solutions were passed through the membranes, an increase in their flux was observed. The presence of surfactants in the solutions lead to a decline in flux when pressures of 0.1 and 0.2 MPa were used, but an improvement could be seen as the pressure increased to 0.3 MPa, for both dead-end and cross-flow filtration. Using only dead-end alternative, higher fluxes were achieved for both membranes, but it decreases with time due to accumulation on the membrane surface. The use of cross-flow filtration did not allow accumulation on the membrane surface so that the flux was constant in time.The use of anionic surfactants improved the food dye retention. The interactions between membranes and surfactants can be an important factor supporting the efficiency of the ultrafiltration.

Modeling of the permeate flux decline during MF and UF cross-flow filtration of soy sauce lees

2008 ◽  
Vol 322 (2) ◽  
pp. 491-502 ◽  
Author(s):  
Toshio Furukawa ◽  
Kenichi Kokubo ◽  
Kazuho Nakamura ◽  
Kanji Matsumoto
Keyword(s):  
Cross Flow ◽  
Soy Sauce ◽  
Permeate Flux ◽  
Cross Flow Filtration ◽  
Flux Decline ◽  
Flow Filtration

scholarly journals Understanding the Role of Pattern Geometry on Nanofiltration Threshold Flux

Membranes ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 445
Author(s):  
Anna Malakian ◽  
Zuo Zhou ◽  
Lucas Messick ◽  
Tara N. Spitzer ◽  
David A. Ladner ◽  
...  
Keyword(s):  
Membrane Surface ◽  
Cross Flow ◽  
Cake Filtration ◽  
Cross Flow Filtration ◽  
Colloidal Fouling ◽  
Computational Fluid Dynamics Simulations ◽  
Flow Filtration ◽  
Dynamics Simulations ◽  
The Relationship

Colloidal fouling can be mitigated by membrane surface patterning. This contribution identifies the effect of different pattern geometries on fouling behavior. Nanoscale line-and-groove patterns with different feature sizes were applied by thermal embossing on commercial nanofiltration membranes. Threshold flux values of as-received, pressed, and patterned membranes were determined using constant flux, cross-flow filtration experiments. A previously derived combined intermediate pore blocking and cake filtration model was applied to the experimental data to determine threshold flux values. The threshold fluxes of all patterned membranes were higher than the as-received and pressed membranes. The pattern fraction ratio (PFR), defined as the quotient of line width and groove width, was used to analyze the relationship between threshold flux and pattern geometry quantitatively. Experimental work combined with computational fluid dynamics simulations showed that increasing the PFR leads to higher threshold flux. As the PFR increases, the percentage of vortex-forming area within the pattern grooves increases, and vortex-induced shielding increases. This study suggests that the PFR should be higher than 1 to produce patterned membranes with maximal threshold flux values. Knowledge generated in this study can be applied to other feature types to design patterned membranes for improved control over colloidal fouling.

scholarly journals Membrane surface properties and their effects on real waste oil-in-water emulsion ultrafiltration

Water SA ◽  
2019 ◽  
Vol 45 (3 July) ◽  
Author(s):  
Marjana Simonič
Keyword(s):  
Surface Properties ◽  
Membrane Fouling ◽  
Membrane Surface ◽  
Cross Flow ◽  
Influential Factors ◽  
Permeate Flux ◽  
Chemical Cleaning ◽  
Water Emulsion ◽  
Oil In Water ◽  
Oil In Water Emulsion

Membrane surface properties and their effect on the efficiency of ultrafiltration (UF) of real waste oily emulsions was studied. Experiments were performed in cross-flow operation at total recycle condition in a lab-scale system. The ceramic UF membrane in the tubular type module was employed. During the experiments permeate flux was measured. The most important influential factors, such as temperature, TMP, and pH, were considered during the experiments. Zeta potential was measured in order to explain the phenomena on the membrane surface. The isoelectric point of the fouled membrane was shifted to the alkaline range. COD removal efficiency reached 89%. Gas chromatography measurements were performed in order to determine the composition of waste emulsions. SEM micrographs showed the formation of calcite on the membrane, which contributed to membrane fouling. Chemical cleaning was examined using alkaline and acid solutions, and a cleaning strategy was determined.

scholarly journals DETERMINATION OF FOULING MECHANISM IN ULTRAFILTRATION OF ELECTROPLATING WASTEWATER

2018 ◽  
Vol 80 (3-2) ◽  
Author(s):  
Danu Ariono ◽  
Anita Kusuma Wardani ◽  
Putu Teta Prihartini Aryanti ◽  
Ahmad Nurul Hakim ◽  
I Gede Wenten
Keyword(s):  
Flow Velocity ◽  
Membrane Fouling ◽  
Membrane Surface ◽  
Cross Flow ◽  
Permeate Flux ◽  
High Concentration ◽  
Filtration Time ◽  
Electroplating Wastewater ◽  
Fouling Mechanism ◽  
Cross Flow Velocity

Wastewater from electroplating industries is usually contaminated with high concentration of hazardous materials, such as nickel, copper, and chromium. Therefore, the electroplating wastewater is one of the environmental problems that require a novel solution to reduce risks for human and environment. Ultrafiltration is a promising technology to overcome this problem due to its ability to reject all suspended solids. However, membrane fouling still becomes a major obstacle in ultrafiltration processes. Fouling reduces the permeate flux and increases membrane operational costs due to membrane cleaning. In this work, fouling mechanism that occurred in polyacrylonitrile based ultrafiltration for electroplating wastewater treatment was investigated. The effects of trans-membrane pressure (TMP) and cross flow velocity on fouling mechanism were also studied. The results showed that in the first 20 minutes, intermediate blocking was occurred on the membrane surface, while cake formation was happened for the rest of filtration time. These results were applied for all TMP and cross flow velocity.

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