DOI: 10.1016/j.watres.2018.04.042
Scopus记录号: 2-s2.0-85047975601
论文题名: Self similarities in desalination dynamics and performance using capacitive deionization
作者: Ramachandran A. ; Hemmatifar A. ; Hawks S.A. ; Stadermann M. ; Santiago J.G.
刊名: Water Research
ISSN: 431354
出版年: 2018
卷: 140 起始页码: 323
结束页码: 334
语种: 英语
英文关键词: Capacitive deionization
; Performance optimization
; Porous carbon electrodes
; Reduced order model
; Self-similarity
; Water desalination
英文摘要: Charge transfer and mass transport are two underlying mechanisms which are coupled in desalination dynamics using capacitive deionization (CDI). We developed simple reduced-order models based on a mixed reactor volume principle which capture the coupled dynamics of CDI operation using closed-form semi-analytical and analytical solutions. We use the models to identify and explore self-similarities in the dynamics among flow rate, current, and voltage for CDI cell operation including both charging and discharging cycles. The similarity approach identifies the specific combination of cell (e.g. capacitance, resistance) and operational parameters (e.g. flow rate, current) which determine a unique effluent dynamic response. We here demonstrate self-similarity using a conventional flow between CDI (fbCDI) architecture, and we hypothesize that our similarity approach has potential application to a wide range of designs. We performed an experimental study of these dynamics and used well-controlled experiments of CDI cell operation to validate and explore limits of the model. For experiments, we used a CDI cell with five electrode pairs and a standard flow between (electrodes) architecture. Guided by the model, we performed a series of experiments that demonstrate natural response of the CDI system. We also identify cell parameters and operation conditions which lead to self-similar dynamics under a constant current forcing function and perform a series of experiments by varying flowrate, currents, and voltage thresholds to demonstrate self-similarity. Based on this study, we hypothesize that the average differential electric double layer (EDL) efficiency (a measure of ion adsorption rate to EDL charging rate) is mainly dependent on user-defined voltage thresholds, whereas flow efficiency (measure of how well desalinated water is recovered from inside the cell) depends on cell volumes flowed during charging, which is determined by flowrate, current and voltage thresholds. Results of experiments strongly support this hypothesis. Results show that cycle efficiency and salt removal for a given flowrate and current are maximum when average EDL and flow efficiencies are approximately equal. We further explored a range of CC operations with varying flowrates, currents, and voltage thresholds using our similarity variables to highlight trade-offs among salt removal, energy, and throughput performance. © 2018 Elsevier Ltd Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/112709
Appears in Collections: 气候减缓与适应
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作者单位: Department of Aeronautics & Astronautics, Stanford University, Stanford, CA 94305, United States; Department of Mechanical Engineering, Stanford University, Stanford, CA 94305, United States; Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore, CA 94550, United States
Recommended Citation:
Ramachandran A.,Hemmatifar A.,Hawks S.A.,et al. Self similarities in desalination dynamics and performance using capacitive deionization[J]. Water Research,2018-01-01,140