The interaction between temperature and flow in wall-cooled catalytic fixed-bed reactors

Vortmeyer, D.; Wagner, Peter M.; Haidegger, E.

doi:10.1016/0009-2509(92)80256-c

Cited by 8 publications

(11 citation statements)

References 7 publications

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“…This conclusion is consistent with Vortmeyer et al's [23] finding that 'for packed beds under typical industrial conditions, the effect of varying fluid properties on the velocity field can be neglected'. Ð R 0 rU z, r ð Þψ z, r ð Þdr, may be expressed as follows (from this point on, = sign will be used instead of ≈ ):…”

Section: The Factorization Modelsupporting

confidence: 92%

A new outlook and a model of reactions in porous media

Otarod

Supkowski

2021

Can J Chem Eng

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A novel method based on cup‐mixing concentration and superficial velocity is presented for the analysis of reactions in isothermal fixed‐bed reactors. It is founded on experimentally observed profiles of concentration and velocity so as to preserve the heterogeneity of a reaction system. The domain of application of the model includes reaction systems at lower Reynolds numbers and Péclet numbers of less than 700 with a void fraction of ϕ for which the ratio of the bed‐length‐to‐particle diameter to particle Péclet number exceeds 0.3ϕ1−ϕ.

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Section: The Factorization Modelsupporting

confidence: 92%

A new outlook and a model of reactions in porous media

Otarod

Supkowski

2021

Can J Chem Eng

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“…Moreover, the hot spot occurs in the tube center. This is a common trend in fixed-bed reactors where exothermic reactions take place. , …”

Section: Resultsmentioning

confidence: 99%

“…This is a common trend in fixed-bed reactors where exothermic reactions take place. 5,29 The results plotted in Figures 6−8 were obtained after 49, 125, and 51 s of computation time, respectively. The longer time for Figure 7 was due to the insertion of the inert layers, which drastically changes the equations' gradient and therefore forces the solver ode15s to decrease the integration step to comply with the predefined tolerances.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

Simulation and Design of a Water-Gas Shift Catalytic Multitubular Reactor with Integrated Heat Exchange

Paixão

Franco

Dangelo

2020

Ind. Eng. Chem. Res.

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A 2D steady-state phenomenological model used for sizing a multitubular catalytic reactor for water-gas shift reaction is presented. The model contemplates momentum, mass, and energy balances. In addition, the thermodynamic behavior is described by the Peng–Robinson–Stryjek–Vera equation of state. After the model validation, a set of equations was used in an optimization procedure to find the optimal reactor’s dimensions and operational conditions, minimizing both capital and operating expenses. The results were compared with data from the literature, and the water-gas shift reaction has proven disadvantageous at a low temperature, with heat exchange, because this considerably increases the required catalyst amount. The multitubular reactor has shown to be appropriate in the studied temperature range (430–520 K) only for a more active catalyst or for a more exothermic reaction.

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“…In particular, the influence of bed temperature inhomogeneities on cooling air flow distribution, of which there are only a few studies. Through numerical modelling of heated gas flow into a bed, several older studies identified the reduction of air flow through higher temperatures bed regions ( Stanek and Szekely, 1973 ; Stanek and Vychodil, 1987 ; Vortmeyer et al, 1992 ; Wonchala and Wynnyckyj, 1987 ). More recently, Davenne et al (2018) highlighted how the presence of a small, near-inlet, cool zone in a heated bed can substantially impact thermocline uniformity during cooling.…”

Section: Introductionmentioning

confidence: 99%

Understanding, controlling and optimising the cooling of waste thermal treatment beds including STARx Hottpads

et al. 2022

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STARx (Self-sustaining Treatment for Active Remediation ex situ) is a thermal treatment strategy for contaminated soils and organic wastes. Key to this technology is that organics are embedded in porous matrix beds (e.g. sand). STARx induces a self-sustaining smouldering combustion front that traverses the bed, burning away the embedded contaminants/wastes. The time and cost effectiveness of this technology is largely dictated by the time required for cooling of the hot, clean, porous matrix bed that remains after treatment. This study is the first to explore the cooling of these beds. A suite of novel simulations investigated the influence of key parameters on bed-cooling time. The results reveal that cooling time decreased nearly linearly with decreases of volume-averaged bed temperature and bed bulk density. Increased injection air fluxes led to the non-linear decrease of cooling time. Also, cooling time was negatively impacted by bed temperature inhomogeneity, which influenced preferential air flow through cooler regions of the bed, bypassing hotter regions. From these results, using lower bulk density bed materials, increased air fluxes and enhancing wall insulation to improve bed temperature homogeneity were identified as system optimisations to reduce cooling times. While the aim of this research is to improve the STARx cooling process, the results are also highly applicable to many similar engineering systems that involve hot porous bed cooling.

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The interaction between temperature and flow in wall-cooled catalytic fixed-bed reactors

Cited by 8 publications

References 7 publications

A new outlook and a model of reactions in porous media

A new outlook and a model of reactions in porous media

Simulation and Design of a Water-Gas Shift Catalytic Multitubular Reactor with Integrated Heat Exchange

Understanding, controlling and optimising the cooling of waste thermal treatment beds including STARx Hottpads

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