Three-dimensional numerical simulation of pressure drop and liquid holdup for high-pressure trickle-bed reactor

This study aims to investigate the hydrodynamic behaviour of a trickle-bed reactor (TBR) at high pressure (30 bar) in terms of pressure drop and liquid holdup after the development of a multiphase model by means of computational fluid dynamics (CFD) codes. Taking into account transport phenomena expressed as interphase coupling terms in the momentum transfer between the gas, liquid and solid phases, an Euler-Euler model was developed resulting from the volume averaging of the continuity and momentum equations and solved for a 3D representation of the catalytic bed. The CFD calculations were validated with experimental data from the literature and different mesh sizes were evaluated for a grid-independent CFD solution of multiphase flow in the packed bed. During grid optimization, coarse and fine physical mesh domains were applied in the hydrodynamic prediction of trickle-bed reactor. After the grid adjustment in terms of number of cells, several spherical particle diameters were tested to study its effect on hydrodynamics and it was found that pressure drop is strongly influenced by the packing size. The Eulerian multiphase model was then used in the computation of pressure drop and liquid holdup and over a wide range for the calculated now regime as a function of gas and liquid flow rates, the CFD theoretical predictions were in good agreement for both hydrodynamic parameters. (C) 2008 Elsevier B.V. All rights reserved.