Experimental and numerical studies on pressure drop in reverse electrodialysis: Effect of unit cell configuration

Hong, Sungkook; Kim, Chan-Soo; Hwang, Kyo-Sik; Han, Ji-Hyung; Kim, Han−Ki; Jeong, Namjo; Choi, Kyung-Soo

doi:10.1007/s12206-016-1047-z

Cited by 5 publications

(7 citation statements)

References 12 publications

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“…Moreover, the compartments were asymmetric, because the viscosity of the concentrated solution (brine) was almost twice that of the dilute feed, thus causing an unbalanced pressure distribution in the two solutions. Larger TMP values (up to ~1.5 bar) were measured by Hong et al [27] in a cross-flow RED stack (35.5 × 35.5 cm 2 ) fed with inlet velocities up to ~5 cm/s, which provided a significantly lower electrical power (less than half) compared to an equivalent parallel-flow stack. Although the authors attributed this decline in performance to issues of internal leakage, an important effect of deformation can be supposed.…”

Section: Introductionmentioning

confidence: 92%

“…However, in prototype and industrial size stacks with non-parallel flow layouts (cross flow, counter flow) and/or with asymmetric channels (different geometries, fluid properties, flow rates), where the pressure distribution in the two compartments is different, appreciable values of TMP may arise. In particular, when some factors enhancing pressure drop are present, TMP values amounting to some tenths of a bar can be exhibited (higher TMP levels can cause severe risks of leakages [25,26,27]).…”

Section: Introductionmentioning

confidence: 99%

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Membrane Deformation and Its Effects on Flow and Mass Transfer in the Electromembrane Processes

Battaglia

Gurreri

Farulla

et al. 2019

IJMS

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In the membrane processes, a trans-membrane pressure (TMP) may arise due to design features or operating conditions. In most applications, stacks for electrodialysis (ED) or reverse electrodialysis (RED) operate at low TMP (<0.1 bar); however, large stacks with non-parallel flow patterns and/or asymmetric configurations can exhibit higher TMP values, causing membrane deformations and changes in fluid dynamics and transport phenomena. In this work, integrated mechanical and fluid dynamics simulations were performed to investigate the TMP effects on deformation, flow and mass transfer for a profiled membrane-fluid channel system with geometrical and mechanical features and fluid velocities representative of ED/RED conditions. First, a conservatively high value of TMP was assumed, and mechanical simulations were conducted to identify the geometry with the largest pitch to height ratio still able to bear this load without exhibiting a contact between opposite membranes. The selected geometry was then investigated under expansion and compression conditions in a TMP range encompassing most practical applications. Finally, friction and mass transfer coefficients in the deformed channel were predicted by computational fluid dynamics. Significant effects of membrane deformation were observed: friction and mass transfer coefficients increased in the compressed channel, while they decreased (though to a lesser extent) in the expanded channel.

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Section: Introductionmentioning

confidence: 92%

Section: Introductionmentioning

confidence: 99%

Membrane Deformation and Its Effects on Flow and Mass Transfer in the Electromembrane Processes

Battaglia

Gurreri

Farulla

et al. 2019

IJMS

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“…The manifolds geometry, along with the channel features and the operating conditions (flow rate and relative direction of the concentrate and diluate streams), also affect the distribution of flow rates (and thus of pressure) among the compartments and in each compartment, with consequences on non-Ohmic resistances, solution leakages from the concentrate channel towards the dilute one and vice versa, and fouling [260,318,[320][321][322][323]. The increase of non-Ohmic resistance arising from a nonuniform distribution of the flow rate can be explained by the exponential reduction of the non-Ohmic resistance with the flow rate.…”

Section: Inlet-outlet Manifolds In Plate and Frame Unitsmentioning

confidence: 99%

“…In this respect, wider manifolds lead to a more uniform delivery of feed solutions flow rate, with beneficial effects in terms of non-Ohmic resistances reduction [260]. Finally, large differential pressures between adjacent compartments cause solution leakages through the membrane [322], occurring especially in counter-current and cross-flow configurations [321].…”

Section: Inlet-outlet Manifolds In Plate and Frame Unitsmentioning

confidence: 99%

Electrodialysis for water desalination: A critical assessment of recent developments on process fundamentals, models and applications

et al. 2018

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“…However, many membrane processes, including ED and RED, may experience membrane deformation due to a transmembrane pressure (TMP) between fluid channels [14][15][16][17][18][19][20]. For example, Hong et al [21] performed experimental and numerical studies of an RED stack with 200 cell pairs, showing a high pressure difference between seawater and fresh water channels.…”

Section: Motivation and Strategy Of The Present Studymentioning

confidence: 99%

Fluid–Structure Interaction and Flow Redistribution in Membrane-Bounded Channels

et al. 2019

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The hydrodynamics of electrodialysis and reverse electrodialysis is commonly studied by neglecting membrane deformation caused by transmembrane pressure (TMP). However, large frictional pressure drops and differences in fluid velocity or physical properties in adjacent channels may lead to significant TMP values. In previous works, we conducted one-way coupled structural-CFD simulations at the scale of one periodic unit of a profiled membrane/channel assembly and computed its deformation and frictional characteristics as functions of TMP. In this work, a novel fluid–structure interaction model is presented, which predicts, at the channel pair scale, the changes in flow distribution associated with membrane deformations. The continuity and Darcy equations are solved in two adjacent channels by treating them as porous media and using the previous CFD results to express their hydraulic permeability as a function of the local TMP. Results are presented for square stacks of 0.6-m sides in cross and counter flow at superficial velocities of 1 to 10 cm/s. At low velocities, the corresponding low TMP does not significantly affect the flow distribution. As the velocity increases, the larger membrane deformation causes significant fluid redistribution. In the cross flow, the departure of the local superficial velocity from a mean value of 10 cm/s ranges between −27% and +39%.

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Experimental and numerical studies on pressure drop in reverse electrodialysis: Effect of unit cell configuration

Cited by 5 publications

References 12 publications

Membrane Deformation and Its Effects on Flow and Mass Transfer in the Electromembrane Processes

Membrane Deformation and Its Effects on Flow and Mass Transfer in the Electromembrane Processes

Electrodialysis for water desalination: A critical assessment of recent developments on process fundamentals, models and applications

Fluid–Structure Interaction and Flow Redistribution in Membrane-Bounded Channels

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