Prediction of flow patterns of rotating inclined reactors using a modified permeability approach

A new inclined rotating tubular fixed bed reactor was recently suggested for process intensification of heterogeneous catalytic multiphase reactions. With that concept, favorable operating conditions can be adjusted operating the reactor in a wetting intermittency mode via periodic catalyst immersion in a stratified gas-liquid flow. This flow pattern adjustment, which requires a careful selection of reactor inclination and rotation, was found to eventually enhance the reaction rate.
In this work an attempt has also been made to predict the flow patterns using computational fluid dynamics. A three-dimensional model based on the relative permeability approach was developed, where gas and liquid phases flow co-currently downwards through the inclined rotating tubular fixed bed reactor. The simulation results are validated against experimental data. The model can clearly predict the four evolving pattern, i.e. stratified, sickle, annular and dispersed flow depending on the operating conditions. In particular, the effect of gas and liquid superficial velocity on liquid saturation and pressure drop for the stratified flow, the most beneficial one with regard to process intensification, was studied in detail, which revealed model predictions within the error range of 15%. It was further verified that the model is capable of correctly predicting the hydrodynamics for aqueous liquid mixtures with varying viscosity and surface tension.