Open Access

ARTICLE

Property Predictions for Packed Columns Using Monte Carlo and Discrete Element Digital Packing Algorithms

by C. Xu¹, X. Jia², R. A. Williams², E. H. Stitt³, M. Nijemeisl,³, S. El-Bachir⁴, L. F. Gladden⁴

1 School of Civil, Environmental and Mining Engineering, University of Adelaide, Australia.
2 Institute of Particle Science and Engineering, School of Process, Environmental and Materials Engineering, University of Leeds, Leeds LS2 9JT, UK.
3 Johnson Matthey Catalysts, Cleveland TS23 1LB, UK.
4 Department of Chemical Engineering, University of Cambridge, Pembroke Street, Cambridge CB2 3RA, UK.

Computer Modeling in Engineering & Sciences 2008, 23(2), 117-126. https://doi.org/10.3970/cmes.2008.023.117

Abstract

Existing theories and computer models for packed columns are either incapable of handling complex pellet shapes or based on over-simplified packing geometry. A digital packing algorithm, namely DigiPac, has recently been developed to fill the gap. It is capable of packing of particles of any shapes and sizes in a container of arbitrary geometry, and is a first step towards a practical computational tool for reliable predictions of packed column properties based on the actual pellet shapes. DigiPac can operate in two modes: a Monte Carlo mode in which particles undergo directional diffusive motions; and a Discrete Element mode where translations and rotations of particles are governed by physical laws. The former is faster but in certain cases less accurate, whereas the latter is slower but produces significantly more accurate predictions. Both modes have been used in simulating packed columns of real pellet shapes. Results for cylinders -- one of the most commonly used shapes for packed columns -- are reported. Comparisons are made between DigiPac predictions under different modes and experimental data obtained using nuclear magnetic resonance (NMR) imaging technique. Good agreement between simulation and NMR results has been observed.

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