A conceptual design of spacers with hairy structures for membrane processes

Li, Weiyi; Chen, Kai K.; Krantz, William B.; Fane, Anthony G.; Tang, Chuyang Y.

doi:10.1016/j.memsci.2016.03.021

Cited by 27 publications

(5 citation statements)

References 47 publications

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“…A column type feed spacer with thinner filament substantially reduced the pressure drop significantly but with the expense of a reduction in fluid unsteadiness [27]. In another study, a hairy type spacer was proposed for a drastic reduction in pressure drop [28]. But, the maximum oscillation of the fibers was only±0.05°.…”

Section: Introductionmentioning

confidence: 99%

Conceptual design of a dynamic turbospacer for efficient low pressure membrane filtration

et al. 2020

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This study presented a conceptual design of a novel dynamic turbospacer to enhance the performance of a low pressure membrane filtration process. It consists of ladder type filaments and a series of microturbine networks within the filament cells. The rotation of the turbines leads to the formation of turbulence in the feed channel that prevents foulants accumulation.Direct numerical simulation (DNS) was conducted to characterize the fluid flow behaviors of the feed channel for the proposed turbospacer and compared with a standard symmetric nonwoven feed spacer. Further, their performances were investigated for a low pressure ultrafiltration (UF) process in a lab-scale experimental setup using 2.8 mm thick 3D printed prototypes of the turbospacer and the standard spacer. Experiments for the proof of this concept were conducted at 173 mL/min and 250 mL/min feed solution inlet velocity when Reynolds number of the flow is 160 and 230 respectively. Substantial reductions in fouling effects using the turbospacer was confirmed by the in-situ Optical Coherence Tomography (OCT) scans of the fouling cake layer accumulated over the membrane during the filtration of seawater with high fouling potential. The proposed turbospacer also lowered the average pressure drop by 4 times and enhanced the specific permeate flux by more than 3 times at 173 mL/min inlet flowratre. At the same operating condition, the specific energy consumption for the turbospacer was found about 2.5 folds lower than the standard spacer.

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Section: Introductionmentioning

confidence: 99%

Conceptual design of a dynamic turbospacer for efficient low pressure membrane filtration

et al. 2020

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“…Various studies on feed spacers have focused on the spacer shape [ 19 , 20 ]. Previous studies employed computational fluid dynamics (CFD) to investigate the effect of spacer shapes, including nonwoven, woven, middle layer, and fully woven spacers [ 21 ]; 30°, 45°, 62°, and 90° spacer filaments [ 22 ]; hairy spacers [ 23 ]; saw-tooth spacers [ 24 ]; zigzag spacers [ 25 ]; multi-layer spacers [ 26 ]; and sinusoidal spacers [ 27 ], on the membrane performance. In addition, with the boost of 3D printing, the design of spacers was affected [ 28 , 29 ], i.e., column-type spacers [ 30 ], triply periodic minimal surfaces (TPMS) spacers [ 31 ], symmetric perforated spacers (1-Hole, 2-Hole, and 3-Hole) [ 32 ], and honeycomb spacers [ 33 ], were fabricated by 3D printing.…”

Section: Introductionmentioning

confidence: 99%

Electrically Polarized Graphene-Blended Spacers for Organic Fouling Reduction in Forward Osmosis

et al. 2021

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In membrane processes, a spacer is known to play a key role in the mitigation of membrane fouling. In this study, the effect of electric polarization on a graphene-blended polymer spacer (e.g., poly(lactic acid), PLA) for organic fouling on membrane surfaces was investigated. A pristine PLA spacer (P-S), a graphene-blended spacer (G-S), and an electrically polarized graphene-blended spacer (EG-S) were successfully fabricated by 3D printing. Organic fouling tests were conducted by the 5-h filtration of CaCl2 and a sodium alginate solution through commercially available membranes, which were placed together with the fabricated spacers. Membranes utilizing P-S, G-S, and EG-S were characterized in terms of the fouling amount on the membrane surface and fouling roughness. Electrostatic forces of EG-S provided 70% less and 90% smoother fouling on the membrane surface, leading to an only 14% less water flux reduction after 5 h of fouling. The importance of nanomaterial blending and polarization was successfully demonstrated herein.

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“…There is no spacer in our membrane device. The oscillations of the hairy structure in the spacers of Li et al do introduce flow fluctuations improving the mass transfer rate to the membrane without introducing too much extra pressure drop. The mass transfer rate enhancement improves due to secondary flows.…”

Section: Introductionmentioning

confidence: 99%

Desalination Performances of Large Hollow Fiber-Based DCMD Devices

Song

Sirkar

2017

Ind. Eng. Chem. Res.

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Saline waters having high osmotic pressure are unsuitable for reverse osmosis desalination. Direct contact membrane distillation (DCMD) can desalt such waters provided the membrane technique is highly resistant to fouling by scaling salts. In DCMD, we had shown earlier that a rectangular cross-flow hollow fiber membrane (HFM) configuration with a specific plasma-polymerized nearly superhydrophobic coating on the membrane ensured no precipitation-based fouling from CaCO3 and CaSO4 for salt concentrations up to 19 wt %. A novel aspect of this method, oscillation of unrestrained HFMs, is illustrated here. Earlier models simulating desalination performance of such devices assumed membrane mass transfer coefficient, k m, as an adjustable parameter for large hollow fiber modules. Here k m was predicted from a recent model without any adjustable parameters, resulting in a better module water vapor flux prediction. To improve membrane module performance and productivity, simulations were carried out by varying hollow fiber ID, HFM length, and the distillate flow rate. The simulation results will help design optimum HFM modules for DCMD-based desalination.

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A conceptual design of spacers with hairy structures for membrane processes

Cited by 27 publications

References 47 publications

Conceptual design of a dynamic turbospacer for efficient low pressure membrane filtration

Conceptual design of a dynamic turbospacer for efficient low pressure membrane filtration

Electrically Polarized Graphene-Blended Spacers for Organic Fouling Reduction in Forward Osmosis

Desalination Performances of Large Hollow Fiber-Based DCMD Devices

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