Three-Dimensional Hydrodynamic Numerical Simulations of Gas-Liquid Flows in Reactor with Ceramic Foams as Internals.

Ceramic foams are promising alternatives for packing internals used in chemical engineering processes due to their high porosity and high specific surface area, which results in low pressure drop and high catalytic utilization of the packing. The application of solid foam packings as catalyst carriers, particularly for gasliquid systems, are not yet well understood. Due to their highly porous nature, it is very tough to understand the interplay between hydrodynamic behaviour and process performance [1]. The aim of this work is to perform three-dimensional Computational Fluid Dynamics (CFD) simulations of the evolving gas-liquid flow patterns considering ceramic foams as column internals and to validate them with experimental X-ray tomographic studies The closures applied for trickle bed simulation studies are modified according to the hydraulic/geometric properties of the ceramic foam considering the flow domain as porous. The influence of the liquid and gas drag is taken into consideration via Relative Permeability approach [2] and added as external source term to the liquid and gas momentum equations separately. The influence of dispersion forces are further included inorder to steady the liquid spreading and liquid saturation. The geometrical parameters of the ceramic foam packing are estimated using µCT image analysis. Empirical correlations proposed in earlier experimental studies are included in 3D CFD models. Initial results of trickle bed reactor simulations were presented earlier [3]. In this work, the validation of CFD simulation with X-ray tomographic experimental studies will be presented and discussed in detail.

Reference 1 :: S. Calvo., d. Beugre.,m.Crine., a. Leonard., p. Marchot.,d.Toye.,phase distribution measurements in metallic foam packing using x-ray radiography and micro-tomography, chemical engineering and processing, 48, 1030–1039 (2009).
Reference 2 :: A.E. Saez,, R.G.Carbonell, Hydrodynamic parameters for gas-liquid cocurrent flow in packed beds,AIChE Journal, Vol. 31, No.1, 52-62 (1985).
Reference 3 :: K.Subramanian, M. Schubert, D. Lucas, U. Hampel, Closures for simulation of gas-liquid flows in solid foam structures, ISCRE23 & APCRE7, Sep 7 – 10 2014, Bangkok, Thailand.