The Investigation And Application Of CFD-PBM Corrected Drag Model In Bubble Column Reactor

Bubble columns are widely used in the biochemical,petrochemical,and environmental process,primarily because of their simple construct with low price,simple operation,excellent heat and mass transfer characteristics,etc.Study on the internal hydrodynamic behavior in such reactors can provide guidance in process optimization,operation and scale-up designing a novel reactor with high performance.In this work,based-on CFD-PBM,the relevant physical models are analyzed and discussed in depth as follow:（1）Three drag models and their corresponding modified models with the wake acceleration are incorporated into the coupled approach in order to evaluate the effectiveness of these drag models.The simulated time-averaged local gas holdups and normalized axial liquid velocities using different drag equations are compared with the experimental data,showing that only the PBM-customized drag model with the wake acceleration（cf.,the application of a correction factor）can reproduce the measured flow field data.Subsequently,the applicability of the coupled approach with the effective drag model is further evaluated at various superficial gas velocities and gas distributors.（2）By combining mass transfer and chemical reactions,CFD-PBM coupled model with the corrected PBM-customized drag model is used to stimulate the reversible two-step reactions found in the chemisorption process of CO₂ in an aqueous NaOH solution in a lab-scale pseudo-2D bubble column reactor.Then,the effects of superficial gas velocity,gas inlet and dimension on gas holdup,bubble plume and the trends of species concentration over time are investigated.