Advanced Modeling for Structured Packing Development - a: Hydraulics

Semi-empirical models such as the Rocha-Bravo-Fair, Delft, and Billet-Schultes models represent the current state-of-the-art in predicting the hydraulic and separation performance of structured packings. However, these models are derived from experimental data that cover a limited range of operating conditions and chemical systems, thus precluding them from being truly predictive. To develop a more robust and predictive hydraulic model for structured packings, computational fluid dynamic (CFD) modeling is utilized to provide greater insight into the multiphase flow physics present inside these packings. Specifically, this study focuses on the observations of transitional and laminar flow structures inside simplified Representative Elementary Units (REUs) of structured packing predicted via CFD modeling of industrially relevant chemical systems. In addition, the impact of these transitional and laminar flow observations on hydraulic model development is discussed. Finally, we present CFD results illustrating that de facto standard turbulence models used previously in the open literature to model flow physics inside structured packings may fail to capture transitional and laminar flow effects properly and thus potentially produce significant errors in predicted pressure drop values.