Multiphase packed-bed reactor

Losey, M. W, Schmidt, M. A., Jensen, K. F., Microfabricated multiphase packed-bed reactors characterization of mass transfer and reactions, Ind. Chem. Res. 

Figure 5.15 Schematic of the multiphase packed bed reactor. Gas inlet (A) liquid distributor (B) catalyst inlets (Q exit port manifold (D) [11].

Reactor type Multiphase packed-bed reactor Gasket material Viton... 

Losey, M.W., M.A. Schmidt, and K.F. Jensen, Microfabiicated multiphase packed-bed reactors Characterization of mass transfer and reactions. Industrial and Engineering Chemistry Research, 2001,40 2555-2562. 

In a multiphase packed bed reactor with porous particles the holdup of a phase consists of that part which is held internally in the pores of the particles and that part which is held externally in the interstices between the packing. The external part can be either free flowing or stagnant, a subdivision which is mainly important for the dispersed phase. 

SCALE-UP PROCEDURES FOR CONCURRENTLY OPERATED MULTIPHASE PACKED BED REACTORS... 

The principle of similarity, i.e. the use of dimensionless groups maintained constant in the course of scale-up, has been characterized even in case of single phase catalytic reactor as limited to simple situations in chemical reactor scale-up. If the overall phenomenon is complex, as in most practical cases, more than one dimensionless group should be kept constant, sometimes leading to contradictory demands. This is certainly true in all practical cases of multiphase packed bed reactors, where also the compromise of weighing the particular effect is only of limited value. Therefore, this method in practice cannot be applied for scale-up of multiphase catalytic reactors. 

This review on concurrently operated multiphase packed bed reactors shows that much information on the behavior of these reactor types has been accumulated in the past, but we are still far from a complete elucidation. The difficulty still exists that not enough information is available on systems different from air/water nonporous packings to safely scale-up multiphase reactors using a sophisticated mathematical model. The fact that fluid-dynamics and thermal effects may be different in laboratory units from those in technical reactors restricts the usefulness of simplified, i.e. lumped, models in reactor scale-up. On the contrary, the different mechanisms acting in multiphase catalytic reactions have to be kept separated to a certain extent, thus enabling the correct inclusion of their probably changing amount of influence during scale-up. 

Marquez N, Castano P, Moulijn JA, Makkee M, Kreutzer MT. Transient behavior and stability in miniaturized multiphase packed bed reactors. Ind. Eng. Chem. Res. 2010 49(3) 1033-1040. 

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