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.

In this paper, we report on the use of a high energy and high resolution X-ray tomograph to visualize and quantify the distribution of liquid hold up and of gas-liquid interfacial area in a 0.1m diameter column filled with MellapakPlus 752.Y packing elements. A standard air-water system at room temperature and atmospheric pressure were used. Tomographic measurements have been carried out in a large number of packing cross sections situated at different heights between the top and the bottom of the packed column, giving access to the evolution of axial profiles of liquid hold up and of gas-liquid interfacial area as a function of the operating conditions. Gas-liquid interfacial area values were also measured by a chemical method (CO2 absorption from air into a caustic solution). For the first time, a whole set of gas-liquid interfacial area values evaluated from tomographic images are interestingly compared with values measured by a chemical method. A comparison is also presented with literature models

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