Thermal imaging of breathing patterns during CO oxidation on a Pd/glass cloth

Digilov, Rafael M.; Nekhamkina, Olga; Sheintuch, Moshe

doi:10.1002/aic.10015

Cited by 29 publications

(23 citation statements)

References 33 publications

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“…Obviously, tracking such symmetry breaking is difficult in large commercial reactors. Infrared imaging revealed temperature pattern formation in various laboratory reactors including the exterior surface of a radial flow reactor6 and the top of shallow packed‐bed reactors7 or the surface of a catalytic cloth8 under oscillatory conditions.…”

Section: Introductionmentioning

confidence: 99%

Transversal patterns in three‐dimensional packed bed reactors: Oscillatory kinetics

Nekhamkina¹,

Sheintuch²

2010

AIChE Journal

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in Wiley Online Library (wileyonlinelibrary.com).Formation of transversal patterns in a 3D cylindrical reactor is studied with a catalytic reactor model in which an exothermic first-order reaction of Arrhenius kinetics occurs with a variable catalytic activity. Under these oscillatory kinetics, the system exhibits a planar front (1D) solution with the front position oscillating in the axial direction. Three types of patterns were simulated in the 3D system: rotating fronts, oscillating fronts with superimposed transversal (nonrotating) oscillations, and mixed rotating-oscillating fronts. These solutions coexist with the planar front solution and require special initial conditions. We map bifurcation diagrams showing domains of different modes using the reactor radius as a bifurcation parameter. The possible reduction of the 3D model to the 2D cylindrical shell model is discussed.

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Section: Introductionmentioning

confidence: 99%

Transversal patterns in three‐dimensional packed bed reactors: Oscillatory kinetics

Nekhamkina¹,

Sheintuch²

2010

AIChE Journal

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“…Wicke and Onken6, 7 noted different temperatures at two locations in the same cross‐section of a packed‐bed reactor. Infrared imaging revealed local hot regions on the exterior surface of a radial flow reactor,8–10 the top of shallow packed‐bed reactors,11–13 and a catalytic fiber cloth 10, 14. Sundarram et al15 found that global coupling between the effluents and the top of the reactor can affect the evolution, stability and shape of the temperature patterns.…”

Section: Introductionmentioning

confidence: 99%

Reactor diameter impact on hot zone dynamics in an adiabatic packed bed reactor

2007

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in Wiley InterScience (www.interscience.wiley.com).Recent analysis revealed that a pseudohomogeneous model of a uniformly active, adiabatic packed bed reactor can predict formation of stable hot zones in the crosssection of the reactor if the kinetic rate expression can lead to isothermal rate oscillations. This prediction was confirmed by simulations of CO oxidation. We show that hot zone formation in a shallow reactor can be predicted also for C 2 H 4 hydrogenation, the kinetic model of which is structurally different from that of CO oxidation. Qualitatively different spatiotemporal temperature patterns may form under the same operating conditions. Their number increases as the reactor diameter is increased. An increase in the reactor diameter increases the time constant of the transversal heat dispersion and decreases the temperature synchronization among points on the same reactor crosssection. The interaction and conjugation among qualitatively different moving temperature patterns can lead to formation of complex motions.

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“…Wicke and Onken3, 4 observed a transversal hot region in a laboratory packed‐bed reactor. Various types of transversal hot regions were observed in a shallow packed‐bed reactor by Marwaha et al5, 6 and on a catalytic glass fiber cloth by Digilov et al7 Transversal hot regions have a deleterious impact on the reactor performance and may pose severe safety hazards when present next to the reactor wall.…”

Section: Introductionmentioning

confidence: 99%

Model prediction of hot spots formation in shallow adiabatic packed‐bed reactors

Viswanathan¹,

Luss²

2005

AIChE Journal

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Transversal hot zones have been observed in many industrial and laboratory reactors. Yet, previous models which utilized rate expressions that depended only on the temperature and concentration of the limiting reactant failed to predict formation of stable hot zones. We previously proved that pseudohomogeneous models of a uniformly active shallow adiabatic packed‐bed reactor cannot predict a bifurcation to stable hot zones when the transversal heat dispersion is larger than that of the species, and the reaction rate depends only on the temperature and concentration of the limiting reactant. We prove here that the same is true also for a two‐phase model of a uniformly active shallow, adiabatic packed‐bed reactor. It is shown that a shallow reactor model, which uses more detailed kinetic expression, may attain stable, transversal hot zones. © 2005 American Institute of Chemical Engineers AIChE J, 2006

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Thermal imaging of breathing patterns during CO oxidation on a Pd/glass cloth

Abstract: Infrared (IR) thermography studies of oscillatory behavior during catalytic oxidation of CO

Cited by 29 publications

References 33 publications

Transversal patterns in three‐dimensional packed bed reactors: Oscillatory kinetics

Transversal patterns in three‐dimensional packed bed reactors: Oscillatory kinetics

Reactor diameter impact on hot zone dynamics in an adiabatic packed bed reactor

Model prediction of hot spots formation in shallow adiabatic packed‐bed reactors

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