Electrogenerated bubbles induced convection in narrow vertical cells: A review

Hreiz, Rainier; Abdelouahed, Lokmane; Fünfschilling, Denis; Lapicque, François

doi:10.1016/j.cherd.2015.05.035

Cited by 69 publications

(28 citation statements)

References 32 publications

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“…It may be hoped that hydrogen bubbling may mitigate cathode fouling [162] and that this virtuous effect will be even more effective at high current density. The mechanisms of hydrogen bubble formation on electrodes have been a traditional research topic in electrochemical engineering for decades [188][189][190], and are still attracting interest [191][192][193][194], notably because bubble formation contributes significantly to the cathode overpotential. This theoretical knowledge has not yet been exploited in the field of MECs and should be helpful for designing the right cathode configurations to mitigate deposits.…”

Section: Consmentioning

confidence: 99%

Microbial electrolysis cell (MEC): Strengths, weaknesses and research needs from electrochemical engineering standpoint

et al. 2020

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Microbial electrolysis cells (MECs) produce hydrogen at the cathode associated with the oxidation of organic matter at the anode. This technology can produce hydrogen by consuming less electrical energy than water electrolysis does. However, it has been very difficult so far to scale up efficient MECs beyond the size of small laboratory cells. This article firstly revisits the fundamentals of MECs to assert their theoretical advantages. The low formal equilibrium cell voltage of 0.123 V and electrical and thermal energy yields as high as 10 and 12, respectively, are major assets. Other theoretical strengths are discussed, including the possibility to produce methane, and some safety advantages. The experimental achievements at pilot scale (several litres volume) are analysed through the prism of electrochemical engineering. This analysis leads to recommendations to modify some research efforts, notably by giving priority to increasing current density rather than working with volumetric parameters, using Faradaic yields to detect dysfunctions, and systematizing control experiments at open circuit. The critical analysis successively addresses electrolytes, electrode kinetics, temperature, substrate concentration, reactor architecture, and control procedures. It brings to light intrinsic weaknesses of the MEC concept and identifies improvements that can be made using current technology, for instance, by the catalysis of hydrogen evolution at neutral pH. The problem of the low electrolyte conductivity is pointed out and, in return, how increasing it can be detrimental to the key issue of anode acidification. Finally, research lines are proposed with the objective of moving ahead towards MEC development.

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Section: Consmentioning

confidence: 99%

Microbial electrolysis cell (MEC): Strengths, weaknesses and research needs from electrochemical engineering standpoint

et al. 2020

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“…CFD models provide accurate simulations of such complex systems. Hreiz et al, 2015 43 summarized CFD hydrodynamics investigations for vertical plane electrode simulated systems. The majority of these studies adapted 2D simulation; however, understanding the nonlinear motion of bubbles requires 3D modelling.…”

Section: Two Phase Electrochemical Systemsmentioning

confidence: 99%

Review—Physicochemical Hydrodynamics of Gas Bubbles in Two Phase Electrochemical Systems

Taqieddin

Nazari

Rajić

et al. 2017

J. Electrochem. Soc.

117

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Electrochemical systems suffer from poor management of evolving gas bubbles. Improved understanding of bubbles behavior helps to reduce overpotential, save energy and enhance the mass transfer during chemical reactions. This work investigates and reviews the gas bubbles hydrodynamics, behavior, and management in electrochemical cells. Although the rate of bubble growth over the electrode surface is well understood, there is no reliable prediction of bubbles break-off diameter from the electrode surface because of the complexity of bubbles motion near the electrode surface. Particle Image Velocimetry (PIV) and Laser Doppler Anemometry (LDA) are the most common experimental techniques to measure bubble dynamics. Although the PIV is faster than LDA, both techniques are considered expensive and time-consuming. This encourages adapting Computational Fluid Dynamics (CFD) methods as an alternative to study bubbles behavior. However, further development of CFD methods is required to include coalescence and break-up of bubbles for better understanding and accuracy. The disadvantages of CFD methods can be overcome by using hybrid methods. The behavior of bubbles in electrochemical systems is still a complex challenging topic which requires a better understanding of the gas bubbles hydrodynamics and their interactions with the electrode surface and bulk liquid, as well as between the bubbles itself.

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“…Many studies have been published on two‐phase flow. These have been excellently discussed in the recent review of Hreiz concerning the modeling of these flows in the case of vertical electrodes .…”

Section: Modelmentioning

confidence: 99%

“…Two‐phase flow models can be classified into two groups: Euler‐Euler and Euler‐Lagrange models . The Euler‐Euler model was chosen in this work since high volume fractions need to be treated, which is trickier with Euler‐Lagrange models.…”

Section: Modelmentioning

confidence: 99%

Multiphysics Model of a Fluorine Electrolysis Cell

Vukasin

Crassous²,

Morel³

et al. 2017

Chem Eng & Technol

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Fluorine production results from the electrolysis of hydrogen fluoride‐based molten salts. This process involves several intimately related phenomena, including two‐phase flow, species transport, electrokinetics, and heat transfer. A multiphysics model was built in order to fully simulate this process and simulation results are compared to experimental data. The emphasis is placed on the process of solidification of the electrolyte on the cooling system and on mass transport close to the cathode. A complex link between bubble generation at the electrodes and species consumption has been highlighted.

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Electrogenerated bubbles induced convection in narrow vertical cells: A review

Cited by 69 publications

References 32 publications

Microbial electrolysis cell (MEC): Strengths, weaknesses and research needs from electrochemical engineering standpoint

Microbial electrolysis cell (MEC): Strengths, weaknesses and research needs from electrochemical engineering standpoint

Review—Physicochemical Hydrodynamics of Gas Bubbles in Two Phase Electrochemical Systems

Multiphysics Model of a Fluorine Electrolysis Cell

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