Packed beds with activated carbon is a commonly used technology for removing unwantedsubstances from a process stream. To better understand how such beds operate and in orderto optimize their design and operation, one-dimensional models are typically employed.The multiphase aspects of these systems are typically neglected due to their complexity,even though regeneration with steam creates a liquid phase that may trickle through thebed, thereby effectively transporting heat and mass. This paper investigates andcharacterizes the differences in transport of gas and liquid in a representative packed bedthrough comprehensive three-dimensional numerical simulations. In addition, the effect ofheterogeneities in the packing of the bed on the transport of both phases is also investigated.It is confirmed that the dispersion of air may be well described by a conventional one-dimensional model, but that the dispersion of water requires an additional effort. It is alsofound that the system orientation significantly influences the water flow and that non-idealpacking has strong effects on the residence time distribution for both phases
