Keywords: Liquid-solid fluidization, CFD-DEM, Radioactive Particle Tracking

Many catalytic processes and operations in the chemical and related industries are carried out in liquid-solid fluidized beds (LSFB). Information of their underlying dynamics is fundamental for proper design of the units and for implementing strategies of process intensification. Moreover, the validation of LSFB modeling to estimate their performance requires comparison with experimental results (Dudukovic & Mills, 2015).

The objective of this work is to compare experimental results obtained with the Radioactive Particle Tracking (RPT) technique in a pilot scale LSFB with those predicted by a Computational Fluid Dynamics coupled with Discrete Element Method (CFD-DEM) model. For this purpose, the motion of calcium alginate spheres induced by the upward flow of water in a cylindrical column (Maestri et al., 2019) is examined.

Simulation of the liquid and solid motion is solved using the CFDEM coupling software (Goniva et al., 2012).  For the liquid phase, the Navier-Stokes equations are solved numerically while for the solid phase the forces acting on the particles (gravity, buoyancy, drag force, solid-solid and liquid-solid surface interactions) are calculated, according to the proposal of Wang et al. (2012). Once the model is validated, the influence of the operating conditions on the particles motion is studied by simulation. The model successfully predicts several observables measured by RPT, such as bed expansion, time averaged velocity fields (Maestri et al., 2019), Kolmogorov entropy, solid phase distribution and solid axial dispersion coefficients.

References

Dudukovic, M.P.; Mills, P.L. / Current opinion in Chemical Engineering, 2015, 9:49-58.

Goniva, C.; Kloss, C.; Deen, N.G.; Kuipers, J.A.M.; Pirker, S. / Particuology, 10 (2012) 582–591

Maestri, M., Salierno, G., Piovano, S., Cassanello, M., Cardona, M.A., Hojman, D., Somacal, H. / Chemical Engineering Journal (2018) in press

Wang, S.; Guo, S.; Gao, J.; Lan, X.; Dong, Q.; Li, X. / Powder Technology, 224 (2012) 365–373