In order to design a reactive distillation for the decomposition of MTBE a feasibility analysis was performed on the basis of thermodynamic considerations. The results led to a reasonable column configuration. A confirmation of the thermodynamic suggestions was derived by simple steady-state simulations of the suggested column set-up. In the next stage of process design a suitable catalyst and column internals were selected. The final task was to develop a scale-up procedure based on experimental data in the lab and pilot scale. While the lab-scale experiments could be described satisfactorily with a simple equilibrium stage model, the same approach failed in the case of pilot-plant experiments. Hydrodynamics, maldistribution, and/or mass transfer limitations might be a reasonable explanation and are worthy of deeper investigation. In order to fit the pilot-plant data to the equilibrium-stage model, a reduced catalyst activity was introduced. As a result we obtained good agreement between model prediction and experimental data in a broad range of operating conditions.
However, with the present state of the art it has to be concluded that experiments at the pilot-plant scale are indispensable for establishing any heterogeneously catalyzed reactive distillation process. Reliable scale-up solely on the basis of laboratory scale experiments does not appear to be possible yet.
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