Axial Dispersion and Wall Effects in Narrow Fixed Bed Reactors : A Comparative Study Based on RTD and NMR Measurements

Titelangaben

Tang, Dahai ; Jess, Andreas ; Ren, Xiaohong ; Blümich, Bernhard ; Stapf, Siegfried:
Axial Dispersion and Wall Effects in Narrow Fixed Bed Reactors : A Comparative Study Based on RTD and NMR Measurements.
In: Chemical Engineering & Technology. Bd. 27 (2004) Heft 8 . - S. 866-873.
ISSN 1521-4125
DOI: https://doi.org/10.1002/ceat.200402076

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Abstract

Axial dispersion and wall effects in narrow fixed beds with aspect ratios < 10 were investigated, both by classical methods and by NMR imaging. The residence time distribution (RTD) in the center and at the wall was measured, system water/NaCl-solution as tracer, and subsequently compared with radial velocity profiles based on NMR imaging. The influence of the aspect ratio and Rep on dispersion and on the degree of non-uniformity of the velocity profile was studied. The NMR results are consistent with the RTD and also with literature data of numerical simulations. For low aspect ratios, dispersion/wall effects have a strong influence on the reactor behavior, above all, in cases where a low effluent concentration is essential, as proven by breakthrough experiments with the reaction of H2S with ZnO.