Peculiarities of ignition of porous systems for natural filtration of a gaseous oxidant

Vaganov, D. A.; Samoilenko, N. G.; Bloshenko, V. N.; Shteinberg, V.G.; Манелис, Г. Б.

doi:10.1016/s0010-2180(01)00290-5

Cited by 3 publications

(3 citation statements)

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“…[2] The balance of hydrophilic and hydrophobic properties of the carbon-air and carbon-electrolyte interfaces determines the performance of such GDE. [3][4][5] This balance is essential to form the "tri-phase interface", an interfacial structure which is a line of contact of the gaseous, liquid, and solid phases responsible respectively for oxygen, hydroxonium ion and electron transport. Designing GDE therefore turns into a task of fabricating functional materials that combine the hydrophilic and hydrophobic properties needed for creating and sustaining such tri-phase interface.…”

Section: Introductionmentioning

confidence: 99%

“…The catalytic layer contains the catalyst bound to the same polymer‐carbon mixture 2. The balance of hydrophilic and hydrophobic properties of the carbon–air and carbon–electrolyte interfaces determines the performance of such GDE 3–5. This balance is essential to form the “tri‐phase interface”, an interfacial structure which is a line of contact of the gaseous, liquid, and solid phases responsible respectively for oxygen, hydroxonium ion and electron transport.…”

Section: Introductionmentioning

confidence: 99%

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Design of Carbon Nanotube‐Based Gas‐Diffusion Cathode for O₂ Reduction by Multicopper Oxidases

Lau

Adkins

Ramasamy

et al. 2011

Advanced Energy Materials

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Multicopper oxidases, such as laccase or bilirubin oxidase, are known to reduce molecular oxygen at very high redox potentials, which makes them attractive biocatalysts for enzymatic cathodes in biological fuel cells. By designing an enzymatic gas‐diffusion electrode, molecular oxygen can be supplied through the gaseous phase, avoiding solubility and diffusion limitations typically associated with liquid electrolytes. In doing so, the current density of enzymatic cathodes can theoretically be enhanced. This publication presents a material study of carbon/Teflon composites that aim to optimize the functionality of the gas‐diffusion and catalytic layers for application in enzymatic systems. The modification of the catalytic layer with multiwalled carbon nanotubes, for example, creates the basis for stronger π–π stacking interactions through tethered enzymatic linkers, such as pyrenes or perylene derivates. Cyclic voltammograms show the effective direct electron contact of laccase with carbon nanotube‐modified electrodes via tethered crosslinking molecules as a model system. The polarization behavior of laccase‐modified gas‐diffusion electrodes reveals open‐circuit potentials of +550 mV (versus Ag/AgCl) and current densities approaching 0.5 mA cm2 (at zero potential) in air‐breathing mode.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Design of Carbon Nanotube‐Based Gas‐Diffusion Cathode for O₂ Reduction by Multicopper Oxidases

Lau

Adkins

Ramasamy

et al. 2011

Advanced Energy Materials

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“…Vaganov et al [21] studied the ignition of a porous layer with natural filtration of gaseous oxidizer through it in a gravity field and with gas density variations during the reaction. This study was made for a onetemperature model using the average temperature of the porous layer and the average filtration velocity.…”

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confidence: 99%

Critical conditions of thermal explosion of a porous layer

Burkina

Prokof’ev

2008

Combust Explos Shock Waves

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The conditions and regimes of thermal ignition of a reactive porous layer are investigated under asymmetric conditions on its lateral surfaces and with an oxidizer supply to the layer by diffusion or filtration through the cold boundary. For a zero-order reaction, an analytical dependence of the critical value of the Frank-Kamenetskii parameter on the Zel'dovich parameter is obtained, which separates the regions of steady-state and unsteady regimes. A numerical analysis is made of the critical value of the Frank-Kamenetskii parameter on the Zel'dovich parameter, the Todes parameter, which determines the oxidizer consumption, and the parameter determining the oxidizer supply to the layer: the Lewis numbers or the filtration analog of the Peclet parameter.Key words: porous medium, natural filtration, critical conditions, thermal explosion, analytical and numerical solutions.The conditions of thermal self-ignition of reactive materials are one of the key issues of fire and explosion safety, and their investigation has therefore proceeded in parallel with the development of ignition and combustion theory, starting from the work of van't Hoff [1]. The critical conditions of thermal self-ignition of homogeneous reactive media with simple kinetics were determined and studied in the classical theories of Semenov [2] and Frank-Kamenetskii [3]. Subsequent investigation has shown that a chemical process or a thermal situation are capable, by virtue of complexity, of significantly changing the self-ignition limit [4]. The special features of chemical processes in porous materials, as was noted even by Zel'dovich [5], are related to the delivery of some reactants to the zone of localization of the chemical process and to the complex heat-transfer mechanism. The indicated specificity results in ignition regimes of porous systems qualitatively different from the ignition regimes of homogeneous media. The ignition limits and times of porous systems and the location of the ignition spot depend greatly on the conditions of the process and are determined by heat and mass transfer.Investigation of the initiation of chemical processes 1 Tomsk State University, Tomsk 634050; roza@ftf.tsu.ru.in porous media has been carried out in three directions: 1) self-ignition; 2) ignition of porous media by a hot body and radiative and convective heat flows; 3) hotspot ignition of porous media. The present paper is concerned with the processes related to the first direction. The effect of heat convection due to gas blowing through a reactive layer on the critical conditions of thermal explosion under symmetric conditions on the layer walls was studied by Eremin and Kolesnikov [6]. Steady-state temperature profiles and the dependence of the critical value of the Frank-Kamenetskii number Fk * on the Peclet parameter Pe were obtained numerically using a one-temperature model for a zero-order chemical process. The dependence for Pe < 4 was approximated by a polynomial with an accuracy of 4%. It was established that, for large values of the Peclet par...

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Thermal explosion in a batch reactor charged with a liquid–solid heterogeneous system

Samoilenko

Корсунский

Bostandzhiyan

et al. 2016

Russ. J. Phys. Chem. B

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Peculiarities of ignition of porous systems for natural filtration of a gaseous oxidant

Cited by 3 publications

References 4 publications

Design of Carbon Nanotube‐Based Gas‐Diffusion Cathode for O₂ Reduction by Multicopper Oxidases

Design of Carbon Nanotube‐Based Gas‐Diffusion Cathode for O₂ Reduction by Multicopper Oxidases

Critical conditions of thermal explosion of a porous layer

Thermal explosion in a batch reactor charged with a liquid–solid heterogeneous system

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Peculiarities of ignition of porous systems for natural filtration of a gaseous oxidant

Cited by 3 publications

References 4 publications

Design of Carbon Nanotube‐Based Gas‐Diffusion Cathode for O2 Reduction by Multicopper Oxidases

Design of Carbon Nanotube‐Based Gas‐Diffusion Cathode for O2 Reduction by Multicopper Oxidases

Critical conditions of thermal explosion of a porous layer

Thermal explosion in a batch reactor charged with a liquid–solid heterogeneous system

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Design of Carbon Nanotube‐Based Gas‐Diffusion Cathode for O₂ Reduction by Multicopper Oxidases

Design of Carbon Nanotube‐Based Gas‐Diffusion Cathode for O₂ Reduction by Multicopper Oxidases