[en] Packing simulations of generic, nonspherical pellets were performed and compared with experimental data sets obtained using X-ray Computerized tomography (CT). Two modified versions of what was previously a purely geometrical, digitally based packing algorithm were implemented. Both are aimed at incorporating the effects of particle interaction forces, one utilizing the distinct element method (DigiDEM) and the other an intermediate solution (collision-guided packing or DigiCGP). This article summarizes the models and the simulations performed using these two modified versions of DigiPac and, for model validation purposes, compares the predicted results with the corresponding X-ray tomographic scans of packed columns, in terms of bulk density, local packing density profiles, and pellet orientation distributions. For packed beds of relatively large and identical pellets, the simulation results indicate that particle-particle and particle-wall interactions cannot be ignored if realistic packing structures are to be obtained by simulation and even a simplistic treatment of these interactions can produce significantly more realistic packing structure than none at all.
Disciplines :
Chemical engineering
Author, co-author :
Caulkin, R.; University of Leeds > Institute of Particle Science and Engineering
Jia, X.; University of Leeds > Institute of Particle Science and Engineering
Xu, C.; Structure Vision Ltd
Fairweather, M.; University of Leeds > Institute of Particle Science and Engineering
Williams, R. A.; University of Leeds > Institute of Particle Science and Engineering
Stitt, H.; Johnson Matthey Catalysts
Nijemeisland, M.; Johnson Matthey Catalysts
Aferka, Saïd ; Université de Liège - ULiège > Département de chimie appliquée > Génie chimique - Opérations physiques unitaires
Crine, Michel ; Université de Liège - ULiège > Département de chimie appliquée > Génie chimique - Opérations physiques unitaires
Léonard, Angélique ; Université de Liège - ULiège > Département de chimie appliquée > Génie chimique - Opérations physiques unitaires - Département de chimie appliquée
Toye, Dominique ; Université de Liège - ULiège > Département de chimie appliquée > Génie de la réaction et des réacteurs chimiques
Marchot, Pierre ; Université de Liège - ULiège > Département de chimie appliquée > Génie chimique - Systèmes polyphasiques
Language :
English
Title :
Simulations of Structures in Packed Columns and Validation by X-ray Tomography
Alternative titles :
[fr] Simulation de la structures de colonnes à empilage et validation par tomographie à rayons X
Strigle, R. F., Jr. Packed Tower Design and Applications: Random and Structured Packings, 2nd ed.; Butterworth-Heinemann: Boston, MA, 1994.
Ridgway, K.; Tarbuck, K. J. Voidage Fluctuations in Randomly-Packed Beds of Spheres Adjacent to a Containing Wall. Chem. Eng. Sci. 1968, 23, 1147.
Roshani, S. Elucidation of Local and Global Structural Properties of packed-bed Configurations. Ph.D. Thesis, Department of Chemical Engineering, University of Leeds, Leeds, U.K., 1990.
Vatani, A. Characterisation of Transport Processes in Packed Beds. Ph.D. Thesis, Department of Chemical Engineering, University of Leeds, Leeds, U.K., 1996.
McGreavy, C.; Foumeny, E. A.; Javed, K. H. Characterisation of Transport Properties for Fixed Beds in Terms of Local Bed Structure and Flow Distribution. Chem. Eng. Sci. 1986, 41, 787.
Jia, X.; Williams, R. A. A Packing Algorithm for Particles of Arbitrary Shapes. Powder Technol. 2001, 120, 175.
Ramaioli, M.; Pournin, L.; Liebling, Th. M. Brazil Nut's Effect Beyond Spherical Grains: Elongation Matters! Presented at the Fifth World Congress on Particle Technology, Orlando, FL, Apr 23-27, 2006.
Seidler, G. T.; Martinez, G.; Seeley, L. H.; Kim, K. H.; Behne, E. A.; Zaranek, S.; Chapman, B. D.; Heald, S. M. Granule-by-Granule Reconstruction of a Sandpile from X-ray Microtomography Data. Phys. Rev. E 2000, 62, 8175.
Richard, P.; Philippe, P.; Barbe, F.; Bourlés, S.; Thibault, X.; Bideau, D. Analysis by X-ray Microtomography of a Granular Packing Undergoing Compaction. Phys. Rev. E 2003, 68, 020301.
Aste, T.; Saadatfar, M.; Sakellariou, A.; Senden, T. J. Investigating the Geometrical Structure of Disordered Sphere Packings. Physica A 2004, 339, 16.
Zhang, W.; Thompson, K. E.; Reed, A. H.; Beenken, L. Relationship between Packing Structure and Porosity in Fixed Beds of Equilateral Cylindrical Particles. Chem. Eng. Sci. 2006, 61, 8060.
Caulkin, R.; Fairweather, M.; Jia, X.; Williams, R. A. A Numerical Investigation into the Simulated Packing of Multi-Tubular Catalytic Reactors. Presented at the 5th International Conference for Conveying and Handling of Particulate Solids, Sorrento, Italy, Aug 27-31, 2006.
Caulkin, R.; Jia, X.; Fairweather, M.; Williams, R. A. An Investigation of Catalyst Packed Columns Using DigiPac. Comput. Chem. Eng. 2006, 30, 1178.
Jia, X.; Gan, M.; Williams, R. A.; Rhodes, D. Validation of a Digital Packing Algorithm in Predicting Powder Packing Densities. Powder Technol. 2007, 174, 10-13.
Xu, C.; Jia, X.; Williams, R. A.; Stitt, E. H.; Nijemeisland, M.; El-Bachir, S.; Sederman, A. J.; Gladden, L. F. Property Predictions for Packed Columns Using Random and Distinct Element Digital Packing Algorithms. Presented at the Fifth World Congress on Particle Technology, Orlando, FL, Apr 23-27, 2006.
Cundall, P. A.; Strack, O. D. L. A Distinct Numerical Model for Granular Assemblies. Geotechnique 1979, 29, 47.
Munjiza, A. The Combined Finite-Discrete Element Method; Wiley: New York, 2004.
Toye, D.; Crine, M.; Marchot, P. Imaging of Liquid Distribution in Reactive Distillation Packings with a New High-Energy X-ray Tomograph. Meas. Sci. Technol. 2005, 16, 2213.
Torquato, S. Random Heterogeneous Materials: Microstructure and Macroscopic Properties; Interdisciplinary Applied Mathematics Series; Springer-Verlag: New York, 2001; Vol. 16.
Gilks, W. R.; Richardson, S.; Spiegelhalter, D. J. Markov Chain Monte Carlo in Practice; Chapman & Hall: Boca Raton, FL, 1996.
