Modeling and Operation of Enzymatic Catalyzed Reactive Wall Columns

The enzymatic catalyzed reactive dividing wall column (eRDWC) is a highly integrated apparatus that combines the advantages of enzymatic catalyst, reactive distillation and dividing wall column technology. Compared to a sequence of lower integrated apparatuses, an eRDWC thus enables significant saving potentials regarding CAPEX and energy use. However, the combination of two already integrated apparatuses to form the RDWC leads to a highly complex process behavior that is characterized by the interaction of phase equilibria, reaction kinetics, enzyme stability, mass transfer and component split in the dividing wall section. Employing an enzymatic catalyst allows a side product free reaction at low column temperatures. It is thus especially promising for reaction systems where conventional chemical catalysts lead to significant side reactions or require very high temperatures that would make the employment of a reactive distillation otherwise impossible.

To successfully operate such a complex apparatus, a reliable process model as well as a comprehension of the underlying process mechanism is required. The following question come to mind: What are the differences to lesser integrated setups? What do we need to know to successfully start up and operate an eRDWC? Can the dynamic and steady state behavior be predicted? How stable is an enzymatic catalyst when employed in a reactive dividing wall column?

This presentation aims to answer these questions by presenting a combination of theoretic ideas, mathematical model and experimental data. First, the basic concept of the eRTWK is presented and differences to lower integrated alternatives are discussed. A rigorous eRTWK model, based on Aspen Custom Modeler, is used to show what assumptions and equations are required to include the additional complexity generated by the higher degree of integration. Experimental data that have been measured at a pilot plant at the institute of process and plant engineering at the Technical University Hamburg, are shown to give the audience an idea of how to operate an eRDWC, what to take in mind when starting it up and what surprising mechanism of enzyme deactivation can occur in this setup. Concluding, the experimental data will be used for a model validation.