This interface (), found under the Chemical Species Transport branch () > Reacting Flow in Porous Media multiphysics node () >  Moving Packed Bed group node, is used to model reactors where the bed, comprised of initially solid reactant particles, move relative to the reactor. As the reactant particles are consumed by heterogeneous reactions from the outside inward, the solid core shrinks, leaving behind a porous layer around it. Apart from the core consuming reactions, transport and reactions inside the porous reacted layer, as well as transport in the pore space around the particles are studied.

The main feature of the interface is the Packed Bed (Moving Packed Bed) node. With the Bed Type parameter being changed from Packed bed to Moving packed bed, the Transport of Diluted Species in Packed Beds interface switches to the Transport of Diluted Species in Moving Packed Beds interface. The effect of the solid bed moving on the mass transport and reaction inside the pellets is described in The Transport of Diluted Species in Moving Packed Beds Interface.

In the Pellets node which is the subnode to the Packed Bed node, With the Pellet Type parameter being changed from Porous catalyst to Shrinking Core model, the Transport of Diluted Species in Moving Packed Beds interface switches to the Transport of Diluted Species in Moving Packed Beds, Shrinking Core interface. In the Transport of Diluted Species in Moving Packed Beds, Shrinking Core interface, the shrinking core reaction occurs at the solid particle outer surface that moves inward into the solid interior, and the fluid (often gas) reactant diffuses through the growing reacted porous layer to the reacting surface. The mass transport and reactions in the reacted porous layer, as well as the size decrease of the unreacted solid core are described in The Transport of Diluted Species in Packed Beds, Shrinking Core.