Upscaling Reverse Electrodialysis

Moreno, Jordi; Grasman, Simon; Engelen, Ronny van; Nijmeijer, Kitty

doi:10.1021/acs.est.8b01886

Cited by 70 publications

(66 citation statements)

References 27 publications

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“…A channel length of 0.6 m allowed for an investigation of the superficial velocities up to~10 cm/s with an inlet-outlet pressure drop below 40 kPa, corresponding to the highest TMP value for which correlations for K were obtained. This size is close to that of square prototype stacks that have actually been used in RED applications [28,29]. The choice of a square stack simplifies the calculations and the interpretation of the results obtained.…”

Section: Flow Arrangement and Boundary Conditionssupporting

confidence: 53%

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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Section: Flow Arrangement and Boundary Conditionssupporting

confidence: 53%

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

et al. 2019

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“…[6]. Such membranes are already being used to develop saline power plants, like reverse electrodialysis (RED) [7]. In these plants, the Gibbs energy of mixing of sea water and brackish water is exploited in areas such as estuaries, where the two aqueous solutions naturally meet.…”

Section: Introductionmentioning

confidence: 99%

Thermoelectric Power of Ion Exchange Membrane Cells Relevant to Reverse Electrodialysis Plants

2019

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A thermoelectric cell is designed and experiments are carried out in order to measure Seebeck coefficients of ion exchange membranes at different constant concentrations of NaCl in water. The purpose of the investigation is to explore how a temperature gradient may be applied to increase the efficiency of saline power plants, in particular, of the process of reverse electrodialysis (RED). To evaluate measurements and RED applications, we derive an expression for the thermoelectric potential for a cell with a single membrane and for a RED unit cell. The Seebeck coefficient is interpreted in terms of the Peltier heat of the cell, and further expressed in terms of transported entropies. We find the Seebeck coefficient of the cell, after correcting for temperature polarization, by gradually increasing the membrane thickness. The contribution to the Seebeck coefficient from the membrane varied between 1.41 and 0.98 mV/K in FUMASEP FKS-PET-75 cation exchange membranes, and between 0.56 and 0.48 mV/K in FUMASEP FAD-PET-75 anion exchange membranes. The precision in the results is 1%, for NaCl concentrations between 0.03 and 0.60 mol/kg. Measurements on the RED unit cell with water samples taken from realistic fresh-and saltwater sources confirmed that a temperature difference has a significant effect, increasing the emf by 1.3% per kelvin of temperature difference.

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“…This increase can be explained by the adjustment in the hydrophobicity-hydrophilicity relation in the membrane [41]. Finally, with the PEI modification of the membrane the properties are similar to those of the Fujifilm Type 10 AEM [71].…”

Section: Results and Discussionmentioning

confidence: 99%

Custom-Made Ion Exchange Membranes at Laboratory Scale for Reverse Electrodialysis

Villafaña-López¹,

Reyes-Valadez²,

Vargas

et al. 2019

Membranes

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Salinity gradient power is a renewable, non-intermittent, and neutral carbon energy source. Reverse electrodialysis is one of the most efficient and mature techniques that can harvest this energy from natural estuaries produced by the mixture of seawater and river water. For this, the development of cheap and suitable ion-exchange membranes is crucial for a harvest profitability energy from salinity gradients. In this work, both anion-exchange membrane and cation-exchange membrane based on poly(epichlorohydrin) and polyvinyl chloride, respectively, were synthesized at a laboratory scale (255 cm2) by way of a solvent evaporation technique. Anion-exchange membrane was surface modified with poly(ethylenimine) and glutaraldehyde, while cellulose acetate was used for the cation exchange membrane structural modification. Modified cation-exchange membrane showed an increase in surface hydrophilicity, ion transportation and permselectivity. Structural modification on the cation-exchange membrane was evidenced by scanning electron microscopy. For the modified anion exchange membrane, a decrease in swelling degree and an increase in both the ion exchange capacity and the fixed charge density suggests an improved performance over the unmodified membrane. Finally, the results obtained in both modified membranes suggest that an enhanced performance in blue energy generation can be expected from these membranes using the reverse electrodialysis technique.

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Upscaling Reverse Electrodialysis

Cited by 70 publications

References 27 publications

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

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

Thermoelectric Power of Ion Exchange Membrane Cells Relevant to Reverse Electrodialysis Plants

Custom-Made Ion Exchange Membranes at Laboratory Scale for Reverse Electrodialysis

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