Scale-up of Reactive Distillation with Sulzer Katapak-S

Heterogeneously catalyzed reactive distillation combines chemical reaction and distillative separation in a single column, with the solid catalyst immobilized in structured packings such as Katapak-S. Although this integration can simplify processes and reduce costs, industrial adoption has been limited mainly due to scale-up uncertainties. This work develops a reliable, model-based design and scale-up methodology using methyl acetate synthesis on Katapak-S as a representative case. The chosen reaction—esterification of methanol with acetic acid—is equilibrium-limited and occurs in a strongly non-ideal mixture, making thermodynamic modeling critical. Key process parameters governing reactive distillation with Katapak-S are identified as a basis for model development. Hydrodynamics and separation performance are investigated experimentally at two scales, including flow regimes, dynamic liquid hold-up, pressure drop, residence-time behavior, and separation efficiency, and correlations for these properties are derived. Using these inputs, reactive distillation models of varying complexity are formulated and compared, including three stage-model variants and a rate-based model, with simulations conducted predictively (without fitting to reactive-distillation experiments). Validation experiments are performed in two columns (50 mm lab scale and 220 mm semi-industrial scale) and used to assess model accuracy. Comparison shows that an equilibrium stage model incorporating reaction kinetics best represents the methyl acetate system, while more detailed models do not provide clear improvements. The findings are consolidated into a practical scale-up procedure for Katapak-S reactive distillation, indicating that development risks need not exceed those of conventional processes. The procedure has been successfully applied by Sulzer Chemtech engineers to design industrial-scale reactive distillation processes.