Stability of Trickle-Bed Reactors

Barkelew, C. H.; Gambhir, B. S.

doi:10.1021/bk-1984-0237.ch004

Cited by 38 publications

(22 citation statements)

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“…The cross section temperature (and conversion) distributions, which are assumed to be uniform in an adiabatic PBR, may undergo symmetry breaking in the transversal (normal to the flow) direction under certain conditions. Several experimental studies reported formation of the hot spots in PBRs 1–5. Obviously, tracking such symmetry breaking is difficult in large commercial reactors.…”

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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“…Matros1 observed hot zones formation in the cross‐section of a packed‐bed reactor in which the catalyst was not uniformly packed. Barkelew and Gambhir2 reported formation of small clumps of molten catalyst (clinkers) during hydrodesulfurization in trickle bed reactors. Jaffe3 reported that a local hot spot was formed by an obstruction to the flow in a hydrogenation trickle‐bed reactor.…”

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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“…Boreskov et al1 and Matros2 observed several, azimuthally nonsymmetric hot zones at the exit of a packed‐bed reactor during the partial oxidation of isobutyl alcohol. Barkelew and Gambhir3 reported the formation of clinkers—small lumps of molten catalyst—during hydrodesulfurization in trickle‐bed reactors. Wicke and Onken4, 5 observed a nonuniformity of transversal temperature in a laboratory packed‐bed reactor during the oxidation of CO. Infrared imaging revealed temperature pattern formation in various laboratory reactors including the exterior surface of a radial flow reactor6, 7 and the top of shallow packed‐bed reactors 8–;11.…”

Section: Introductionmentioning

confidence: 99%