Packed Bed

Use this feature to model a packed bed reactor filled with solid catalytic pellets. The bed pellets are porous, forming a bimodal porosity in the reactor. In addition to mass transfer and reactions in the fluid between the pellets (interparticle processes), the same processes can also be studied inside the pellets (intraparticle). The pellets are available in each point of the bed domain, and are defined using an extra dimension describing the pellet radius.

The includes two subnodes, and , which in turn are used to define the physical properties of the corresponding phase. The latter node is also used to define volumetric reactions, as well as heterogeneous reactions, occurring within the porous pellets.

The node requires a Porous Material (described in the COMSOL Multiphysics Reference Manual) on the domains occupied by the bed. Using the porous material it is possible to model a bed comprised of any number of pellet types by adding multiple pellet nodes.

For information on the equations solved in the pore space and inside the pellets see the section The Packed Bed Feature, in the Theory for the Transport of Diluted Species Interface chapter. When using the corresponding feature for concentrated mixtures, see The Packed Bed Feature in the Theory for the Transport of Concentrated Species Interface chapter.

For an application using the Packed Bed feature, see

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A Multiscale 3D Packed Bed Reactor: Application Library path

Web link: https://www.comsol.com/model/a-multiscale-3d-packed-bed-reactor-17019

Domain Selection

From the list, choose the domains with porous material. Note that all domains chosen needs to be occupied by a .

Bed Properties

Use the list to specify the bed porosity, that is the volume fraction not occupied by the pellets. Select to use the bed porosity defined by the . Select to enter a constant or an expression.