High-Temperature Transients in Catalytic Fixed-Bed Reactors

Yakhnin, V. Z.; Menzinger, Michael

doi:10.1515/revce.2004.20.3-4.175

Cited by 20 publications

(25 citation statements)

References 32 publications

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“…It would be desirable to assess the significance of amplification through a suitable criterion (Yakhnin and Menzinger, 2004a). Experiments with thick-and thin-wall reactor demonstrated the inverse dependence of amplification on axial heat conduction of the bed and tube combined, while experiments with high-and low-concentration catalyst (Damkohler number) showed that at high concentration the reaction zone is steep and amplification negligible.…”

Section: Theoretical Considerationsmentioning

confidence: 99%

“…A demonstration (Yakhnin and Menzinger, 2004a) of how the width of the reaction zone affects amplification is given in Fig. 11 where the steady state temperature profiles of a first order reaction is shown for two values of the reduced activation energy = 15, 21 in the bottom panels.…”

Section: Numerical Confirmationmentioning

confidence: 99%

“…We conclude that the rate of axial heat dispersion in the reaction zone plays the key role. A simple criterion proposed recently by Yakhnin and Menzinger (2004a) will be discussed. This criterion allows assessment from only the steady state temperature profile whether THS will be a problem or not.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Dynamic responses of packed bed reactors

Menzinger

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Jaree

et al. 2004

Chemical Engineering Science

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Section: Theoretical Considerationsmentioning

confidence: 99%

Section: Numerical Confirmationmentioning

confidence: 99%

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Dynamic responses of packed bed reactors

Menzinger

Yakhnin

Jaree

et al. 2004

Chemical Engineering Science

Self Cite

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“…The extent of the reaction, which leads to a depletion of the reactants, as well as the heat dispersion contact the DIFI as inhibitors . The reactor is stable if the inhibitor can balance local activator fluctuations . However, a sufficiently large differential flow moves the activator and the inhibitor against each other causing the DIFI.…”

Section: Introductionmentioning

confidence: 99%

“…The wrong‐way behavior describes the temporary increase of the reactor temperature, due to a sudden and permanent drop of the feed temperature and vice versa . The maximum temperature rise can be noticeably higher than the adiabatic temperature rise .…”

Section: Introductionmentioning

confidence: 99%

Transient Flow Rate Ramps for Methanation of Carbon Dioxide in an Adiabatic Fixed‐Bed Recycle Reactor

2019

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The power‐to‐gas (PtG) process, enabling the long‐term indirect storage of electrical energy, includes the water electrolysis for hydrogen production and the subsequent hydrogenation of carbon dioxide in a methanation reactor. The dynamic operation of methanation reactors is favored to limit upstream storage capacities, but not fully understood thus far. Therefore, this contribution investigates the dynamic operation of a fixed‐bed recycle reactor during flow rate ramps with a variation of the ramp time. Load ramps of the volumetric flow rate lead to global maxima during the transition; for the methane content if the flow rate is decreased, and for the gas temperature if the flow rate is increased. Furthermore, the adaptation of the product recirculation during flow rate ramps is discussed at the end. The recycle ratio turns out to provide an additional degree of freedom for stabilizing the reactor behavior under fluctuating feed conditions.

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Hot zones formation during regeneration of diesel particulate filters

2011

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A diesel particulate filter (DPF) is used to remove particulate matter (PM) from the diesel engine exhaust. The accumulated PM is periodically removed by combustion, which sometimes leads to excessive temperature excursions that melt the ceramic filter. This behavior cannot be explained by operation under stationary feed conditions. We propose that these temperature excursions are a dynamic effect following a rapid change in the driving mode while the DPF is being regenerated. Specifically, a rapid decrease in the exhaust temperature can lead to a counterintuitive large transient temperature rise above that which would exist under a higher stationary feed temperature. This unexpected behavior is similar to the well-known wrong-way behavior in packedbed reactors, even though the axial-dependent flow through the filter in a DPF is rather different from the constant axial flow through a packed bed. We present simulations that provide insight about the dependence of the amplitude of this wrong-way temperature rise on the filtration velocity, the PM loading, dimensions of the DPF, and the amplitude of the rapid temperature decrease and when it occurs after the start of the regeneration. The insight provided by these simulations will help develop operation and control protocols that circumvent or at least decrease the probability of the occurrence of the destructive melting of the DPF. V

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High-Temperature Transients in Catalytic Fixed-Bed Reactors

Cited by 20 publications

References 32 publications

Dynamic responses of packed bed reactors

Dynamic responses of packed bed reactors

Transient Flow Rate Ramps for Methanation of Carbon Dioxide in an Adiabatic Fixed‐Bed Recycle Reactor

Hot zones formation during regeneration of diesel particulate filters

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