Numerical Simulation of Hydrodynamics in a Turbulent Contact Absorber: A Simplified Approach

In the current work, hydrodynamics of a turbulent contact absorber (TCA) was studied in terms of bed pressure drop and expanded bed height by adopting a simplified modeling approach. The study was carried out computationally using the Eulerian multifluid model in ANSYS Fluent^® where the packing was treated as a granular material. In order to simplify the complex three-phase system, it was reduced to a two-phase configuration by considering the solid packing and liquid water as a single phase with appropriate modifications. Both the laminar and turbulent viscous models were tested to study the bed characteristics at different values of liquid and gas flow rates. The covered range of liquid velocity was 0.004–0.012 m/s and that of gas velocity was 1.8–3.6 m/s. It was found that laminar model was able to produce better results as compared to turbulent one. The simulation results for pressure drop across the bed agreed well with the published experimental data. However, for a fixed gas velocity with variable liquid holdup, the bed expansion displayed a reverse trend as compared to experiments. Hence, the current model can be used to predict bed pressure drop of TCA-type systems, but not the expanded bed height.