True moving bed reactor

Counter-current Chromatographic Reactors 8.2.3.1 True Moving Bed Reactor... 

A counter-current flow of solid and fluid offers the advantage of continuous operation. The easiest concept of such a reactor is the true moving bed reactor (TMBR). It is a direct adoption of the true moving bed (TMB) process explained in Chapter 5.3.4. 

This shows how catalytic reactions compare with other interfacial reactions. In a fixed bed reactor the catalyst (in phase ) has an infinite residence time, which can be ignored in the expressions we derived in previous chapters. For a moving bed reactor in which catalyst moves through the reactor, we have a true multiphase reactor because the residence time of the catalyst phase is not infinite. 

Two different modeling approaches are used for simulated moving bed reactors. The first approach combines the model of several batch columns with the mass balances for the external inlet and outlet streams. By periodically changing the boundary conditions the transient behavior of the process is taken into account. The model is based on the SMB model introduced in Chapter 6 and is, therefore, referred to as the SMBR model. The second approach assumes a true counter-current flow of the solid and the liquid phase like the TMBR. Therefore, this approach is called the TMBR model. 

Fig. 7. Schematic presentation of a true countercurrent moving bed chromatographic reactor. (Reprinted with permission from [151])...

F. Lode, M. Mazzotti, M. Morbidelli, Comparing true countercurrent and Simulated Moving-Bed chromatographic reactors. AIChEJ., 2003,... 

Lode, F., Mazzotti, M., Morbidelli, M. Comparing true countercurrent and simulated moving-bed chromatographic reactors, AIChE /., 2003a, 49, 4, 977-990. 

Because their true advantages appear only if flow reactors are customized for the exact reaction they facilitate, there is a great variety of flow reactor systems. Designing contact modes for reactants with catalysts, which is required for most reactors, has led to further design variations. Typically, catalysts either remain stationary as reactants flow along or through them in a packed (or fixed-) bed reactor, or catalysts move with reactants in a fluidized bed reactor. 

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