CFD Simulations of Bubble Column Equipped with Bundles of Concentric Tubes

Bubble column reactors are multiphase contactors that have found several industrial applications owing to various attractive features including excellent thermal management, low maintenance cost due to simple construction and absence of moving parts. In order to attain desired performance for a given application, these reactors are usually equipped with internals such as vertical tube bundles to facilitate heat transfer. The column hydrodynamics and turbulence parameters are altered when the column is occluded with internals which adds to the complexity of the problem. The use of Computational Fluid Dynamics (CFD) tools for the study of multiphase flows has gained a lot of traction over the recent years. In the current study, CFD is applied to a 2-Dimensional Eulerian-Eulerian model coupled with Population Balance Model (PBM) to simulate bubble column reactors in the presence and absence of internals. The significance of various interfacial forces on the numerical solution has been reviewed. Based on this, a suitable model is chosen which appropriately simulates the gas-liquid flow and has been selected to perform flow transition studies which covers the bubbly, transition and churn-turbulent regime. An increase in hydrodynamic parameters like centerline liquid axial velocity and gas holdup was noticed when the bubble column was occluded with circular tube internals. Furthermore, when dense vertical internals were introduced, the hydrodynamic values varied and consequently increased. When internals were added, a significant variation was noticed in the flow pattern which contributed to superior qualities of mixing