Significance of the radial porosity profile for the description of heat transport in wall-cooled packed beds

Borkink, J.G.H.; Westerterp, K.R.

doi:10.1016/0009-2509(94)80023-5

Cited by 33 publications

(18 citation statements)

References 34 publications

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“…Borkink and Westerterp (1994) also used a two‐region model, but their wall region was quite broad and depended on N and Re. Their model retained k r and h w as their intent was to show the influence of v z ( r ) and ε ( r ) on the estimation of the traditional parameters.…”

Section: Alternatives To the Kr–hw Approachmentioning

confidence: 99%

Small angle X‐ray scattering as a complementary tool for high‐throughput structural studies

et al. 2011

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Structural crystallography and Nuclear Magnetic Resonance (NMR) spectroscopy are the predominant techniques for understanding the biological world on a molecular level. Crystallography is constrained by the ability to form a crystal that diffracts well and NMR is constrained to smaller proteins. While powerful techniques they leave many soluble, purified protein samples structurally uncharacterized. Small Angle X-ray Scattering (SAXS) is a solution technique that provides data on the size and multiple conformations of a sample, and can be used to reconstruct a low resolution molecular envelope of a macromolecule. In this study SAXS has been used in a high-throughput manner on a subset of 28 proteins where structural information is available from crystallographic and/or NMR techniques. These crystallographic and NMR structures were used to validate the accuracy of molecular envelopes reconstructed from SAXS data on a statistical level, to compare and highlight complementary structural information that SAXS provides, and to leverage biological information derived by crystallographers and spectroscopists from their structures. All of the ab initio molecular envelopes calculated from the SAXS data agree well with the available structural information. SAXS is a powerful albeit low-resolution technique that can provide additional structural information in a high-throughput and complementary manner to improve the functional interpretation of high-resolution structures.

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Section: Alternatives To the Kr–hw Approachmentioning

confidence: 99%

Small angle X‐ray scattering as a complementary tool for high‐throughput structural studies

et al. 2011

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“…Vortmeyer and Winter (1984) and Dixon and Yoo (1991)]. At such small tube-to-particle diameter ratios the dimensions of the particle are not negligible in comparison with that of the tube diameter so the applicability of continuum models becomes quite doubtful_ Also a wall effect is present due to the structured arrangement of the particles near the wall, leading to an increased porosity near the wall and to wall channelling [see Vortmeyer and Haidegger (1991), Daszkowki and Eigenberger (1992) and Borkink and Westerterp (1994)]. Because particles are ordered only within the first layers from the wall, the effect is more pronounced for fewer particles on a diameter.…”

Section: Theoretical Backgroundsmentioning

confidence: 99%

Oxidation of ethene in a wall-cooled packed-bed reactor

Schouten

Borman

Westerterp

1994

Chemical Engineering Science

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Abstract--The selective oxidation of ethene over a silver on cx-alumina catalyst was studied in a pilot plant with a wall-cooled tubular packed bed reactor. Gas and solid temperatures in the catalyst bed were measured at different axial and radial positions as well as concentrations at different axial position. Total pressure, inlet mole fraction ethene, mass flow rate and wall temperature were varied_ The experiments are compared with model calculations. A pseudo-homogeneous model and a heterogeneous two-dimensional model were used for the calculations. Kinetics and heat transport parameters in the model have been determined independently in separate studies_ The work is distinctive in the accuracy paid to a large number of experimental details. The models correspond reasonably well with the experiments at all operating conditions. The main problem in the description of the reactor is the inability of the kinetic expressions to predict the reaction rates over the entire range of partial pressures. As a result some systematic deviations are found, in particular in the predicted temperature profiles. The heterogeneous model gives better agreement with the experiments although systematically larger temperature differences are calculated on the basis of available correlations in literature than has been measured. On the basis of this work it is difficult to determine directly whether an influence of chemical reaction is present on the values of the heat transport parameters.

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“…where expressions for K, A, and B are given elsewhere (see Vortmeyer and Schuster, 1983;Borkink and Westerterp, 1994). The porosity and velocity distributions are shown in Figure 2, where the wall effect can be clearly discerned.…”

Section: Reactor Modelmentioning

confidence: 99%

Transient Runaway in a Fixed-Bed Catalytic Reactor

Henda¹

2008

Modelling and Simulation

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Significance of the radial porosity profile for the description of heat transport in wall-cooled packed beds

Cited by 33 publications

References 34 publications

Small angle X‐ray scattering as a complementary tool for high‐throughput structural studies

Small angle X‐ray scattering as a complementary tool for high‐throughput structural studies

Oxidation of ethene in a wall-cooled packed-bed reactor

Transient Runaway in a Fixed-Bed Catalytic Reactor

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