The state of the art equilibrium model and the rate-based models for reactive distillation (RD) are very well known and have been used since a couple of decades. However, these models are not sufficient to accurately represent a slow reaction process that is kinetically controlled. The shortcoming is due to neglecting the effect of liquid back mixing (LBM) on the whole process. This work presents a review of the available modeling approaches for RD, then discusses the applicability of various models and finally, it applies the findings to an industrially relevant case study-polyester synthesis. The main focus is on extending the dynamic rate-based model to take into account the liquid back mixing. We also show how the axial dispersion can be introduced into the RD model, without adopting the axial dispersion model. The comparison of the results of the rate-based model, with and without axial dispersion, clearly demonstrates that the extended model predicts more accurately the kinetically controlled process as compared to the conventional rate-based model.
- Aspen Custom Modeler
- Axial dispersion
- Liquid back mixing
- Product changeover
- Reactive distillation modeling