Current problems in the modelling of chemical reactors

Thoenes, D.

doi:10.1016/0009-2509(80)80133-3

Cited by 9 publications

(3 citation statements)

References 16 publications

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“…The tube-to-particle diameter ratio is a crucial value for the prediction of the behaviour of such reactors and their mathematical modelling (Carberry 1981;Thoenes 1980;Vortmeyer 1983). For large aspect ratios, i.e.…”

Section: Technical Relevance Of¯xed-bed Reactors With Small Aspect Ramentioning

confidence: 99%

“…To ensure the optimal reaction conditions, advanced numerical estimates are necessary during the design process. The tube-to-particle diameter ratio is a crucial value for the prediction of the behaviour of such reactors and their mathematical modelling (Carberry 1981;Thoenes 1980;Vortmeyer 1983). For large aspect ratios, i.e.…”

Section: Technical Relevance Of¯xed-bed Reactors Withmentioning

confidence: 99%

“…Industrially used aspect ratios depend on the reaction system and the technical realization. The aspect ratio can be as low as 1.5{9.4 for isomerization reactors, 3{4 for the synthesis of phthalic anhydride and 5.6{8.5 for vinyl acetate synthesis, just to mention a few technical systems described in the literature (see, for example, Carberry 1981; Thoenes 1980;Vortmeyer & Winter 1983;Winter 1983, and the references therein). A recent patent of ABB Lummus Global Inc. (1999) describes the application of structured packings in tubes with a rectangular cross-section and even smaller aspect ratios.…”

Section: Technical Relevance Of¯xed-bed Reactors Withmentioning

confidence: 99%

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Analysis of the flow field and pressure drop in fixed-bed reactors with the help of lattice Boltzmann simulations

Zeiser

Steven²,

Freund³

et al. 2002

Philosophical Transactions of the Royal Society of London. Seri

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The pressure drop of technical devices is a crucial property for their design and operation. In this paper, we show how the results of lattice Boltzmann simulations can be used in science and engineering to improve the physical understanding of the pressure drop and the flow inhomogeneities in porous media, especially in sphere-packed fixed-bed reactors with low aspect ratios. Commonly used pressure drop correlations are based on simplified assumptions such as the capillary or tortuosity model, which do not reflect all hydrodynamic effects. Consequently, empirical correlations for certain classes of media have been introduced in the past to bridge the gap between the models and the experimental findings. As is shown in this paper by the detailed analysis of the velocity field in the void space of packed beds, the pressure drop is due to more complex hydrodynamics than considered in the above-mentioned models. With the help of lattice Boltzmann simulations, we were able to analyse the different contributions to the total dissipation, namely shear and deformation of the fluid, for different geometries over a wide range of Reynolds numbers. We further show that the actual length of the flow paths changes considerably with the radial and circumferential position.

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Section: Technical Relevance Of¯xed-bed Reactors With Small Aspect Ramentioning

confidence: 99%

Section: Technical Relevance Of¯xed-bed Reactors Withmentioning

confidence: 99%

Section: Technical Relevance Of¯xed-bed Reactors Withmentioning

confidence: 99%

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