Scale-up and Modelling of Flow-electrode CDI Using Tubular Electrodes

He, Calvin; Lian, Boyue; Ma, Jinxing; Zhang, Changyong; Wang, Yuan; Mo, Hengliang; Waite, T. David

doi:10.1016/j.watres.2021.117498

Cited by 27 publications

(18 citation statements)

References 49 publications

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“…For example, Nordstrand et al recently designed a parallel arrangement of cells with symmetrically distributed flows to maintain a low pressure drop across the system . Another challenge during scale up of CDI is to make the process continuous, which has been the focus of FCDI ,,, and multichannel MCDI ,,, systems. The latter enables continuous production of both fresh and brine streams by periodically switching the products of the middle and side channels .…”

Section: Performance Comparisons and Process Intensificationmentioning

confidence: 99%

“…Technoeconomic analyses of CDI also show the importance of achieving long system lifetimes, as capital costs (e.g., electrodes, membranes, frames, current collectors) are expected to outweigh operating costs (e.g., electricity, materials, labor). ,, In particular, it is necessary to understand and mitigate electrode degradation , (see section ) and cell fouling (see section ). Several other publications on CDI optimization and pilot systems provide additional design rules and principles for scale up. ,,,,,,,− …”

Section: Performance Comparisons and Process Intensificationmentioning

confidence: 99%

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Electrochemical Methods for Water Purification, Ion Separations, and Energy Conversion

et al. 2022

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Agricultural development, extensive industrialization, and rapid growth of the global population have inadvertently been accompanied by environmental pollution. Water pollution is exacerbated by the decreasing ability of traditional treatment methods to comply with tightening environmental standards. This review provides a comprehensive description of the principles and applications of electrochemical methods for water purification, ion separations, and energy conversion. Electrochemical methods have attractive features such as compact size, chemical selectivity, broad applicability, and reduced generation of secondary waste. Perhaps the greatest advantage of electrochemical methods, however, is that they remove contaminants directly from the water, while other technologies extract the water from the contaminants, which enables efficient removal of trace pollutants. The review begins with an overview of conventional electrochemical methods, which drive chemical or physical transformations via Faradaic reactions at electrodes, and proceeds to a detailed examination of the two primary mechanisms by which contaminants are separated in nondestructive electrochemical processes, namely electrokinetics and electrosorption. In these sections, special attention is given to emerging methods, such as shock electrodialysis and Faradaic electrosorption. Given the importance of generating clean, renewable energy, which may sometimes be combined with water purification, the review also discusses inverse methods of electrochemical energy conversion based on reverse electrosorption, electrowetting, and electrokinetic phenomena. The review concludes with a discussion of technology comparisons, remaining challenges, and potential innovations for the field such as process intensification and technoeconomic optimization.

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Section: Performance Comparisons and Process Intensificationmentioning

confidence: 99%

Section: Performance Comparisons and Process Intensificationmentioning

confidence: 99%

Electrochemical Methods for Water Purification, Ion Separations, and Energy Conversion

et al. 2022

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“…In CDI, a detailed interplay between desalination adsorption rate and migration of ions determines the efficiency of ion removal. , Thus, while some modeling work is zero-dimensional (0D), − others use one-dimensional (1D) spatial resolution across the thickness of a CDI device, ,,− 1D along the length, partial two-dimensional (2D), or full 2D. , Some recent work even introduced simplified three-dimensional (3D) simulations for CDI and coupled 3D steady-state simulations of flow-electrode CDI . Such spatial simulations could identify concentration shocks, local dead zones in the device, flux distributions in new structures, etc. However, the complex interconnected processes in CDI can make modeling unsteady, which limits the detail and applicability of coupled spatiotemporal simulations in higher dimensions.…”

Section: Introductionmentioning

confidence: 99%

Fully 3D Modeling of Electrochemical Deionization

2023

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Electrochemical deionization devices are crucial for meeting global freshwater demands. One such is capacitive deionization (CDI), which is an emerging technology especially suited for brackish water desalination. In this work, we extend an electrolytic capacitor (ELC) model that exploits the similarities between CDI systems and supercapacitor/battery systems. Compared to the previous work, we introduce new implementational strategies for enhanced stability, a more detailed method of describing charge efficiency, layered integration of leakage reactions, and theory extensions to new material and operational conditions. Thanks to the stability and flexibility the approach brings, the current work can present the first fully coupled and spatiotemporal three-dimensional (3D) CDI model. We hope that this can pave the way toward generalized and full-scale modeling of CDI units under varying conditions. A 3D model can be beneficial for investigating asymmetric CDI device structures, and the work investigates a flow-through device structure with inlet and outlet pipes at the center and corners, respectively. The results show that dead (low-flow) areas can reduce desalination rates while also raising the total leakage. However, the ionic flux in this device is still enough under normal operating conditions to ensure reasonable performance. In conclusion, researchers will now have some flexibility in designing device structures that are not perfectly symmetric (real-life case), and hence we share the model files to facilitate future research with 3D modeling of these electrochemical deionization devices.

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“…The velocity of flow electrodes at corners is less than that at straight lines, resulting in the poor consistency of the desalination performance in whole flow channels. Ma et al developed a novel FCDI system consisting tubular electrodes in a shell and tube heat exchanger configuration, which promoted the flow uniformity of carbon slurry in the tubular flow channel and achieved a high desalination performance of 0.15 mg s –1 at 1.2 V . This work inspires us to pay more attention to the flow channel structure for the improvement of the desalination performance in FCDI devices.…”

Section: Introductionmentioning

confidence: 99%

Enhanced Desalination Performance by a Novel Archimedes Spiral Flow Channel for Flow-Electrode Capacitive Deionization

Zhang

Zhou

et al. 2022

ACS EST Eng.

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As an emerging desalination technology, flow-electrode capacitive deionization (FCDI) has aroused extensive attraction due to its advantage of pseudoinfinite adsorption capacity. However, some problems still remain in the traditional FCDI devices, i.e., its streaming and seeping quality which has severely limited the progress. Herein, some improvements were achieved by changing the direction of saline water in spacer. Furthermore, the Archimedes spiral flow channel model was introduced to improve the flow behavior of carbon slurry in the FCDI unit cell for the first time, which has vastly boosted the desalination performance of FCDI devices. The computational fluid dynamics (CFD) simulation revealed the more uniform velocity distribution and longer residence time of carbon slurry in spiral flow channels to enhance the desalination, while the flow rate of carbon slurry in a straight line is faster but slower in the corner of serpentine flow channels, causing a negative effect on the desalination performance. After long-term continuous desalination in 3.5 g L–1 NaCl solution at 2.4 V, 99.88% of salt removal efficiency was achieved with a superior salt removal rate of 4.06 μmol cm–2 min–1 and 98.9% charge efficiency for the spiral flow channel FCDI device, demonstrating a stable desalination performance.

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Scale-up and Modelling of Flow-electrode CDI Using Tubular Electrodes

Cited by 27 publications

References 49 publications

Electrochemical Methods for Water Purification, Ion Separations, and Energy Conversion

Electrochemical Methods for Water Purification, Ion Separations, and Energy Conversion

Fully 3D Modeling of Electrochemical Deionization

Enhanced Desalination Performance by a Novel Archimedes Spiral Flow Channel for Flow-Electrode Capacitive Deionization

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