Design of Reactive Distillation Column for Non-Parameterized Components - Which Experiments Are Essential

Design of reactive distillation column for non-parameterized components - which experiments are essential

Litzmann, O., TU Berlin, Berlin; Lorenz, H.-M., TU Berlin, Berlin; Wozny, G., TU Berlin, Berlin; Grützner, T., Lonza AG, Visp/CH; Repke, J.-U., TU Freiberg, Freiberg   

Designing reactive distillation processes requires a great number of fitted parameters depending on the model used. These parameters are known for test-systems like MTBE or TAME but not for systems which have never before used in reactive distillation. As fitting of parameters require a lot of time and money for trials it is crucial to know the impact of an improved model to the prediction accuracy. If this is known it is possible to carry out fewer experiments with and fit a set of sufficient parameters in order to describe the RD process as good as needed to strive the goal.

Application to a new industrial substance system

The system analysed consists of an organic acid, an alcohol, the corresponding ester and water whereupon some components cannot be described by standard UNIFAC methods. The esterfication takes place in a reactive distillation column designed for this system. The reaction is catalysed by the heterogeneous catalyst Amberlyst 36.

In order to describe the results of the column, models are used which take different phenomena into account and use different sets of parameters which have been measured independently. 

Fig.  SEQ Fig. \* ARABIC 1: Comparison of the composition forecast by pseudo homogeneous and adsorption based model

For instance the reaction can be described either by equilibrium or by kinetics – which can be corrected by adsorption effects in addition. This kinetic have been measured in a batch reactor and is described with significant higher accuracy by an adsorption based kinetic model (see Fig.1) The portability of these model improvement and similar effects to the reactive column simulation will be presented and discussed by means of comparison with the experimental results from the lab scale plant.