CFD modeling and simulation of clogging in packed beds with nonaqueous media

When liquids containing low concentrations of fine solid impurities are treated in packed‐bed reactors, clogging develops and starts hampering the flow severely. This phenomenon, called deep‐bed filtration, constitutes serious concern over hydrotreating or hydrocracking of bituminous sands in packed‐bed reactors, in which such nonfilterable fines as native clay or incipient coke cause reactor dysfunction by clogging. A detailed k‐fluid Eulerian 2‐D transient computational‐fluid dynamic (CFD) model was formulated to describe the space‐time evolution of clogging patterns developing in deep‐bed filtration of the liquids. A local formulation of the macroscopic logarithmic filtration law is proposed, as well as a geometrical model for the effective specific surface area of momentum exchange. Both mono‐ and multiple‐layer deposition mechanisms were accounted for by including appropriate filter coefficient formulations. Transient, 2‐D axisymmetrical simulations were benchmarked using experimental results and observations of Narayan et al. (1997) of the carbon‐black contaminated kerosene flow through packed beds. Comparing the simulations and experiments showed that CFD is useful for the quantitative description of packed‐bed clogging.