(140b) Novel Modeling of Liquid-Phase Hydrodynamics and Mass Transfer in Structured Packings

Structured packings are advanced column internals for chemical separation equipment, including distillation columns. This type of packing offers high separation efficiency, low pressure drop, and high throughputs. Opportunity for further improvement to these packings exist, but development efforts are challenged by an incomplete understanding of the hydrodynamics and mass transfer inside the system. This presentation describes a novel computational fluid dynamics (CFD) approach to capture the hydrodynamics and mass transfer in these packings. Multiple validation sources confirmed the accuracy of the simulations. CFD predictions of the liquid holdup were compared with two separate experimental data sources and showed strong agreement. Predictions of the liquid flow angle were compared with an analytical expression and showed exceptional agreement. The CFD predictions of the Fanning friction factor aligned with falling film theory. Lastly, the predicted liquid mass transfer coefficients showed strong agreement with experimental data taken from a pilot-scale column. The validated CFD model subsequently supported a packing design study, where the packing design was modified, and the hydrodynamic and mass transfer performances were characterized. Reducing the channel opening angle to 60° and the channel inclination angle to 30° increased the liquid mass transfer coefficient by 12.4% and 18.0%, respectively. This improvement in mass transfer was driven by higher liquid flow angles and, therefore, higher liquid upheaval.