An Eulerian-Eulerian Computational Approach for Simulating Descending Gas-Liquid Flows in Reactors with Solid Foam Internals

Chemical reactors with new types of packings, such as metallic and ceramic open-pore foams, have become of subjects of scientific and engineering interest in the past decades. For so-called trickle bed reactors the new packing types provide favorable conditions, such as a high specific surface area and low pressure drop, which are believed to contribute to an intensification of mass and heat transfer. While a number of experimental studies have been recently been reported in literature, hydrodynamic modelling and simulation, particularly at the full reactor scale, is still in its infancy due to the complexity of two-phase flow in such non-regular packings.
In this work, an attempt has been made to model and predict flow pattern and liquid distribution in a trickle bed reactor with solid foams using computational fluid dynamics. A three-dimensional model based on the relative permeability approach was adopted, where gas and liquid phases flow co-currently downwards through a reactor with SiSiC ceramic foams as internals. The influence of both mechanical and capillary dispersion is included and studied in detail for foams of two different pore densities. The simulation results are validated against experimental data. In particular, the effects of gas and liquid superficial velocities and pore density on liquid holdup and two-phase pressure drop were studied in detail.