Flow distribution in a randomly packed hollow fiber membrane module

Zheng, Jumeng; Xu, Yuan; Xu, Zuhua

doi:10.1016/s0376-7388(02)00426-x

Cited by 64 publications

(32 citation statements)

References 11 publications

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“…The packing of the fibers within a module has been observed to be very different axially [111], which causes some non-uniformity in the flow. Due to the complexity of the hydrodynamics in the module [111][112][113][114][115][116], the buildup of cake deposits is not likely to be uniform either among the fibers or along the fiber surface. The misdistribution of fouling deposits, which is acknowledged to be a direct function of the non-uniformity of the flow within the HF module [109,115,[117][118][119][120][121][122], can result in large variations in the performance of fibers at the same position in the module and in poorer performance of the fibers in the middle of the module [108].…”

Section: Blocking and Blocking Mitigation In Submerged Hf Modulesmentioning

confidence: 99%

The Performance and Fouling Control of Submerged Hollow Fiber (HF) Systems: A Review

et al. 2017

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Abstract:The submerged membrane filtration concept is well-established for low-pressure microfiltration (MF) and ultrafiltration (UF) applications in the water industry, and has become a mainstream technology for surface-water treatment, pretreatment prior to reverse osmosis (RO), and membrane bioreactors (MBRs). Compared to submerged flat sheet (FS) membranes, submerged hollow fiber (HF) membranes are more common due to their advantages of higher packing density, the ability to induce movement by mechanisms such as bubbling, and the feasibility of backwashing. In view of the importance of submerged HF processes, this review aims to provide a comprehensive landscape of the current state-of-the-art systems, to serve as a guide for further improvements in submerged HF membranes and their applications. The topics covered include recent developments in submerged hollow fiber membrane systems, the challenges and developments in fouling-control methods, and treatment protocols for membrane permeability recovery. The highlighted research opportunities include optimizing the various means to manipulate the hydrodynamics for fouling mitigation, developing online monitoring devices, and extending the submerged HF concept beyond filtration.

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Section: Blocking and Blocking Mitigation In Submerged Hf Modulesmentioning

confidence: 99%

The Performance and Fouling Control of Submerged Hollow Fiber (HF) Systems: A Review

et al. 2017

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“…6 However, there are limited reports available on improving fluid dynamics and designing hollow fiber modules for MD applications in the open literature [22][23][24][25]. Some relevant studies have focused on the effect of packing density, flow maldistribution and hydrodynamic behavior in the shell side of hollow fiber modules, based on studies of various gas-liquid/ liquid-liquid contactors [26][27][28][29][30][31]. It is widely accepted that non-ideal flow distribution leads to less active membrane area and insufficient mass transfer, and thus poor module performance.…”

Section: Introductionmentioning

confidence: 99%

Performance improvement of PVDF hollow fiber-based membrane distillation process

Yang

Wang

Shi

et al. 2011

Journal of Membrane Science

231

144

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The performance of membrane distillation depends on both membrane and module characteristics. This paper describes strategies to improve the performance of hollow fiber membrane modules used in Direct Contact Membrane Distillation (DCMD).Three different types of hydrophobic polyvinylidene fluoride (PVDF) hollow fiber membrane (unmodified, plasma modified and chemically modified) were used in this study of Direct Contact Membrane Distillation (DCMD). Compared to the unmodified PVDF hollow fiber membrane, both modified membranes showed greater hydrophobicity and mechanical strength, smaller maximum pore sizes and narrower pore size distributions, leading to more sustainable fluxes and higher water quality (distillate conductiviy < 1µs·cm -1 ) over a one month test using synthetic seawater (3.5 wt% sodium chloride solutions).Comparing the plasma and chemical modification the latter has marginally better performance and provides potentially more homogeneous modification.MD modules based on shell and tube configuration were tested to identify the effects of shell and lumen side flow rates, fiber length and packing density. The MD flux increased to an asymptotic value when shell-side Re f was larger than 2500, while the permeate/lumen side reached an asymptotic value at much lower Re p (>300). By comparing the performance of small and larger modules, it was found that it is important to utilize a higher shell-side Re in the operation to maintain a better mixing near the membrane surface in a larger module.Single fiber tests in combination with heat transfer analysis, verified that a critical fiber 3 length existed that is the required length to assure sufficient driving force along the fiber to maintain adequate MD performance. In addition, for multi-fiber modules the overall MD coefficient decreased with increasing packing density, possibly due to flow maldistribution.This study shows that more hydrophobic membranes with a small maximum pore size and higher liquid entry pressure are attainable and favorable for MD applications. In order to enhance MD performance various factors need to be considered to optimize fluid dynamics and module configurations, such as fiber length, packing density and the effect of module diameter and flow rates.

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“…In spite of the absence of comprehensive module design work for MD applications, numerous prior studies have been done for general gas-liquid/ liquid-liquid contactors with focuses on the introduction of turbulence promoters (baffles/spacers/channel designs) or special housing configurations as well as on various aspects related to packing density, flow uniformity and shell-side hydrodynamics [21,[28][29][30][31][32][33]. These studies concluded that non-ideal flow distribution in a module will lead to less active membrane area, insufficient mixing and local loss of driving force, and hence low heat-or mass-transfer efficiencies.…”

Section: Introductionmentioning

confidence: 99%

Novel designs for improving the performance of hollow fiber membrane distillation modules

Yang

Wang

Fane

2011

Journal of Membrane Science

125

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Five types of novel hollow fiber module configurations with structured-straight fibers, curly fibers, central-tubing for feeding, spacer-wrapped and spacer-knitted fibers, have been designed and constructed for the Direct Contact Membrane Distillation (DCMD) process. Their module performances were evaluated based on permeation flux experiments, fluid dynamics studies, and tracer-response tests for flow distribution as well as process heat transfer analysis.The novel designs showed flux enhancement from 53% to 92% compared to the conventional module, and the spacer-knitted module had the best performance. The fluxes of all the modified configurations, except the structured-straight module, were independent of the feed flow velocity, and the modules with undulating membrane surfaces (curly and spacer-knitted fibers) were able to achieve more than 300% flux improvement in the laminar flow regime. The improved performance was attributed to the improved fiber geometries or arrangements that can provide effective boundary layer surface renewal and more uniform flow distribution, confirmed by the sodium chloride tracer response

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Flow distribution in a randomly packed hollow fiber membrane module

Cited by 64 publications

References 11 publications

The Performance and Fouling Control of Submerged Hollow Fiber (HF) Systems: A Review

The Performance and Fouling Control of Submerged Hollow Fiber (HF) Systems: A Review

Performance improvement of PVDF hollow fiber-based membrane distillation process

Novel designs for improving the performance of hollow fiber membrane distillation modules

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