Multi-Scale Modeling of Tubular Cross-Flow Microfiltration of Metalworking Fluids

2012 ◽  
Author(s):  
Nathan P. Sullivan ◽  
John E. Wentz ◽  
John P. Abraham
Keyword(s):  
Membrane Surface ◽  
Cross Flow ◽  
Membrane Resistance ◽  
Metalworking Fluids ◽  
Transmembrane Pressure ◽  
Flow Profile ◽  
Micro Model ◽  
Machining Processes ◽  
Alumina Membrane ◽  
Tubular Membrane

Metalworking fluids are a vital part of modern machining processes but have significant negative economic, health, and environmental impacts. In-process purification of these fluids by microfiltration has been shown to reduce these impacts. This research uses a two-stage computational modeling methodology to investigate how particles within the membrane are transported from the turbulent flow within the center of the tubular membrane to the laminar sub-layer near the membrane wall and finally into the membrane pores. A macro-model of the complete flow within the tubular membrane is used to determine the steady-state flow profile within 25 microns of the membrane surface. This flow profile is then used to develop a micro-model of the flow at the membrane wall using a flat-plate assumption. The micro-model includes individual pores randomly located and sized based on statistical analysis of alumina membrane surfaces. A 23 full factorial design of experiments was used with variables of cross-flow velocity, transmembrane pressure, and membrane resistance. The responses of effective filtration region and total mass flowing through the pores were analyzed. Based on the simulation results, recommendations are made for future membrane design to provide the most efficient transport of particles from the bulk into the pores.

Dynamic Simulations of Alumina Membrane Fouling From Recycling of Semisynthetic Metalworking Fluids

2008 ◽  
Vol 130 (6) ◽  
Author(s):  
John E. Wentz ◽  
Shiv G. Kapoor ◽  
Richard E. DeVor ◽  
N. Rajagopalan
Keyword(s):  
Membrane Fouling ◽  
Fluid Dynamic ◽  
Cross Flow ◽  
Metalworking Fluids ◽  
Alumina Membrane ◽  
Dynamic Simulations ◽  
Membrane Pores ◽  
Alumina Membranes ◽  
Membrane Flux ◽  
Partial Blocking

The recycling of semisynthetic metalworking fluids (MWFs) using alumina membranes is significantly impacted by aggregated MWF microemulsions that cause partial and complete blocking of membrane pores. In this paper, computational fluid dynamic methods are employed to model both a portion of a sintered alumina membrane with tortuous pores and the microemulsions passing through it. Several particle size distributions, measured experimentally at various times through the membrane service life and under two different cross-flow velocities, were used to determine the particle sizes simulated in the flow. Simulated MWF particles smaller than the largest pore diameter were found to completely block the pore through the build-up of a network of particles that blocked smaller diameter inlets and outlets. The results demonstrate as well that significant membrane flux reduction can occur by partial blocking of pore inlets and outlets even in the absence of complete blocking.

scholarly journals Membrane-integrated hybrid bioremediation of industrial wastewater: a continuous treatment and recycling approach

2013 ◽  
Vol 3 (1) ◽  
pp. 26-38 ◽  
Author(s):  
Ramesh Kumar ◽  
Parimal Pal
Keyword(s):  
Membrane Surface ◽  
Pure Water ◽  
Cross Flow ◽  
Hybrid Plant ◽  
Hazardous Substances ◽  
Continuous Treatment ◽  
Transmembrane Pressure ◽  
Treatment Unit ◽  
Coke Wastewater ◽  
High Degree

A new membrane-integrated hybrid treatment system was investigated to turn highly hazardous coke wastewater reusable. This could protect both air and surface water bodies from toxic contaminants such as ammonia, phenol, cyanide, thiocyanate and other carcinogenic aromatic compounds which are normally released into the environment during discharge of coke wastewater and during quenching of coke by wastewater. Apart from these hazardous substances, oil, grease, other organics and even trace elements could be very effectively removed from wastewater by logical sequencing of chemical, biological and finally nanomembrane-based treatments in an integrated hybrid plant. After almost 99% removal of highly toxic cyanide compounds in a well-optimized Fenton's treatment unit, subsequent biological treatment units could be very effective. All these pretreatments helped achieve microbial nitrification and denitrification of more than 98% of ammonia. Composite nanofiltration membranes selected through investigation could separate ionic trace contaminants from water with a high degree of purification permitting recycling and reuse of the treated water. A selected cross flow membrane module allowed long hours of largely fouling-free operation under a reasonably low transmembrane pressure of only 15 bars while yielding an industrially acceptable flux of 80 L of pure water per hour per square meter of membrane surface.

Performance Investigation of Membrane Process in Natural Gas sweeting by Membrane Process: Modeling Study

2016 ◽  
Vol 11 (1) ◽  
pp. 23-27 ◽  
Author(s):  
Kamran Ghasemzadeh ◽  
Mostafa Jafari ◽  
Amir sari ◽  
Ali A. Babalou
Keyword(s):  
Experimental Data ◽  
Natural Gas ◽  
Membrane Surface ◽  
Cross Flow ◽  
Flow Patterns ◽  
Transmembrane Pressure ◽  
Membrane Process ◽  
Membrane Area ◽  
Membrane Performance ◽  
Aspen Hysys

Abstract The main purpose of this work is the numerical investigation of PEBX membrane performance for natural gas sweeting. Hence, a single-stage process for PEBX membrane was considered in various flow patterns, namely, cocurrent, cross flow and countercurrent to separate a typical natural gas mixture. To this target, a black box numerical model was extended for the ASPEN HYSYS commercial package and also its validation was realized by litterature experimental data. The validation results indicated a good agreement between thoritical results and experimental data. After model validation, the effect of the some significant operating parameters (pressure gradient, stage cut and membrane area) on the performance of PEBX membrane was analysed in terms of acid gases removal percentage. The simulation results presented a noticeable performance of PEBX membrane to produce high purity CH4. In particular, concerning the stage cut effect, it was found that the CO2 and H2S compositions in the permeate side were decreased through the enhancment of stage cut from 0.005 to 0.03, whereas the CH4 composition increased for whole the flow patterns. Moreover, a similar effect was achived for membrane surface area. On the other hand, the transmembrane pressure effect was positive on the PEBX membrane performance during natural gas sweeting.

Formation and prevention of hardly removable particle layers in inside-out capillary membranes operating in dead-end mode

2003 ◽  
Vol 3 (5-6) ◽  
pp. 117-124 ◽  
Author(s):  
S. Panglisch
Keyword(s):  
Boundary Conditions ◽  
Membrane Surface ◽  
Cross Flow ◽  
Membrane Resistance ◽  
Permeate Flux ◽  
Dead End ◽  
Capillary Membrane ◽  
Theoretical Predictions ◽  
Capillary Membranes ◽  
Geometrical Boundary

Although numerous ultra- and microfiltration dead-end plants with capillary membranes are already operative, some phenomena are still unexplained. Therefore, the fundamental processes taking place inside a capillary membrane were observed. Initially, the flow field depending on axial and radial position inside the capillary was determined. Then, particle transport and deposition were theoretically studied by determination of particle trajectories considering influences of particle concentration and walleffects on hydrodynamics, DLVO-forces, buoyancy, gravitation, diffusion and interparticular forces. Following these calculations, incoming particles with a diameter smaller than the so-called “limiting diameter”, which depends on operational and geometrical boundary conditions, due to depositions are widely and evenly distributed. Larger particles do not deposit until they are at a certain distance from the water inlet. The larger the particle size, the longer the distance. If the particle is larger than the so-called “corkforming diameter” then the particles are transported to the dead-end of the capillary which may cause a clogging of the capillary. This “corkforming diameter” depends on operational as well on geometrical boundary conditions. These theoretical predictions are confirmed by experimental results from investigations with spherical latex and non-spherical walnut particles. To avoid this clogging, the deposition of the particles should be evenly distributed, which means that the “corkforming diameter” should be as large as possible. That goal could be achieved by operating the membrane plant with short and/or wide capillaries. However, a small permeate flux, a small membrane resistance and/or a small membrane surface potential succeed as well. Another possibility could be to operate the capillaries with a very small cross flow.

scholarly journals Effect of Modifying the Membrane Surface with Microcapsules on the Flow Field for a Cross-Flow Membrane Setup: A CFD Study

Membranes ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 555
Author(s):  
Sebastian Osterroth ◽  
Christian Neumann ◽  
Michael Weiß ◽  
Uwe Maurieschat ◽  
Alexandra Latnikova ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Flow Field ◽  
Membrane Surface ◽  
Cross Flow ◽  
Transmembrane Pressure ◽  
Membrane Fabrication ◽  
Membrane Biofouling ◽  
Comparison Results ◽  
Computational Fluid Dynamics Cfd

In this study, the attachment of microcapsules on the membrane surface and its influence on the flow field for a cross-flow membrane setup are investigated. The microcapsules were placed on the top layer of the membrane. The overall purpose of this modification was the prevention of membrane biofouling. Therefore, in a first step, the influence of such a combination on the fluid flow was investigated using computational fluid dynamics (CFD). Here, different properties, which are discussed as indicators for biofouling in the literature, were considered. In parallel, different fixation strategies for the microcapsules were experimentally tested. Two different methods to add the microcapsules were identified and further investigated. In the first method, the microcapsules are glued to the membrane surface, whereas in the second method, the microcapsules are added during the membrane fabrication. The different membrane modifications were studied and compared using CFD. Therefore, virtual geometries mimicking the real ones were created. An idealized virtual geometry was added to the comparison. Results from the simulation were fed back to the experiments to optimize the combined membrane. For the presented setup, it is shown that the glued configuration provides a lower transmembrane pressure than the configuration where microcapsules are added during fabrication.

scholarly journals Simulation of the nanofiltration of pulping black liquor by dynamic blade cross-flow with membrane

BioResources ◽  
2020 ◽  
Vol 15 (3) ◽  
pp. 5593-5615
Author(s):  
Wenjie Zhao ◽  
Zhongyu Du ◽  
Ning Kuang ◽  
Hao Wang ◽  
Benliang Yu ◽  
...  
Keyword(s):  
Rotation Speed ◽  
Lignin Content ◽  
Dynamic Pressure ◽  
Membrane Surface ◽  
Black Liquor ◽  
Tangential Velocity ◽  
Cross Flow ◽  
Transmembrane Pressure ◽  
Nanofiltration Membrane ◽  
Fluent Software

This paper investigated the filtration of black liquor with blade cross-flow by membrane. The lignin content in black liquid filtered by the nanofiltration membrane (NP010) is high under the transmembrane pressure of 0.5 bar, 1 bar, 1.5 bar, and 2 bar at 300 rpm and 800 rpm. In this regard, the tangential velocity on the nanofiltration membrane surface and the pressure variation on the blade in the process of filtration are simulated and analyzed with Fluent software. The tangential flow velocity on the nanofiltration membrane surface and the dynamic pressure on the blade, as well as the law of change under different rotation speed and transmembrane pressure are obtained. The comparison between experimental and simulated results have validated the numerical model of the filtration of black liquid by the blade dynamic cross-flow. According to the experimental and simulated results, the optimized filtration conditions are obtained when the blade dynamic cross-flow uses 1 kDa nanofiltration membrane to filter black liquor.

Low-pressure membrane filtration with unconventional coagulation regimes

2005 ◽  
Vol 5 (5) ◽  
pp. 1-8 ◽  
Author(s):  
K.Y. Choi ◽  
B.A. Dempsey
Keyword(s):  
Activated Carbon ◽  
Membrane Filtration ◽  
Membrane Surface ◽  
Cross Flow ◽  
Chemical Cleaning ◽  
Sand Filters ◽  
Charge Neutralization ◽  
Floc Size ◽  
Filtration System ◽  
Pre Treatment

The objective of the research was to evaluate in-line coagulation to improve performance during ultrafiltration (UF). In-line coagulation means use of coagulants without removal of coagulated solids prior to UF. Performance was evaluated by removal of contaminants (water quality) and by resistance to filtration and recovery of flux after hydraulic or chemical cleaning (water production). We hypothesized that coagulation conditions inappropriate for conventional treatment, in particular under-dosing conditions that produce particles that neither settle nor are removed in rapid sand filters, would be effective for in-line coagulation prior to UF. A variety of pre-treatment processes for UF have been investigated including coagulation, powdered activated carbon (PAC) or granular activated carbon (GAC), adsorption on iron oxides or other pre-formed settleable solid phases, or ozonation. Coagulation pre-treatment is often used for removal of fouling substances prior to NF or RO. It has been reported that effective conventional coagulation conditions produced larger particles and this reduced fouling during membrane filtration by reducing adsorption in membrane pores, increasing cake porosity, and increasing transport of foulants away from the membrane surface. However, aggregates produced under sweep floc conditions were more compressible than for charge neutralization conditions, resulting in compaction when the membrane filtration system was pressurized. It was known that the coagulated suspension under either charge-neutralization or sweep floc condition showed similar steady-state flux under the cross-flow microfiltration mode. Another report on the concept of critical floc size suggested that flocs need to reach a certain critical size before MF, otherwise membranes can be irreversibly clogged by the coagulant solids. The authors were motivated to study the effect of various coagulation conditions on the performance of a membrane filtration system.

Ultrafiltration of silica sols

1989 ◽  
Vol 54 (1) ◽  
pp. 91-101 ◽  
Author(s):  
Milan Stakić ◽  
Slobodan Milonjić ◽  
Vladeta Pavasović ◽  
Zoja Ilić
Keyword(s):  
Particle Size ◽  
Silica Particle ◽  
Specific Resistance ◽  
Membrane Surface ◽  
Membrane Resistance ◽  
Experimental Conditions ◽  
Surface Unit ◽  
Silica Sols ◽  
Filtration Flux ◽  
Batch Cell

Ultrafiltration of three laboratory made silica and two commercial silica sols was studied using Amicon YC membrane in a 200 ml capacity batch-cell. The effect of silica particle size, stirring conditions, pressure, pH and silica contents on ultrafiltration was investigated. The results obtained indicate that the smaller particles have, disregarding the stirring conditions, lower filtration flux. The differences observed in filtration flux are more pronounced in the conditions without stirring. The obtained value of the membrane resistance is independent of the conditions investigated (stirring, pressure, pH, silica contents and particle size). The values of the resistance of polarized solids, specific resistance, and the mass of gel per membrane surface unit were calculated for all experimental conditions.

scholarly journals Tanning Wastewater Treatment by Ultrafiltration: Process Efficiency and Fouling Behavior

Membranes ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 461
Author(s):  
Fu Yang ◽  
Zhengkun Huang ◽  
Jun Huang ◽  
Chongde Wu ◽  
Rongqing Zhou ◽  
...  
Keyword(s):  
Wastewater Treatment ◽  
Shear Rate ◽  
Membrane Surface ◽  
Filtration Efficiency ◽  
Operating Conditions ◽  
Process Efficiency ◽  
Transmembrane Pressure ◽  
Leather Industry ◽  
Pore Blocking ◽  
The Impact

Ultrafiltration is a promising, environment-friendly alternative to the current physicochemical-based tannery wastewater treatment. In this work, ultrafiltration was employed to treat the tanning wastewater as an upstream process of the Zero Liquid Discharge (ZLD) system in the leather industry. The filtration efficiency and fouling behaviors were analyzed to assess the impact of membrane material and operating conditions (shear rate on the membrane surface and transmembrane pressure). The models of resistance-in-series, fouling propensity, and pore blocking were used to provide a comprehensive analysis of such a process. The results show that the process efficiency is strongly dependent on the operating conditions, while the membranes of either PES or PVDF showed similar filtration performance and fouling behavior. Reversible resistance was the main obstacle for such process. Cake formation was the main pore blocking mechanism during such process, which was independent on the operating conditions and membrane materials. The increase in shear rate significantly increased the steady-state permeation flux, thus, the filtration efficiency was improved, which resulted from both the reduction in reversible resistance and the slow-down of fouling layer accumulate rate. This is the first time that the fouling behaviors of tanning wastewater ultrafiltration were comprehensively evaluated, thus providing crucial guidance for further scientific investigation and industrial application.

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