Pressure drop in one stage and two-stages of packed columns

Abstract

Packed reactors are broadly used in the chemical industries and are considered as a multiphase reactors. The optimization of these reactors is influenced by many parameters which the most important is the pressure drop. Thus, the aim of this paper is to study the effect of pressure drop along the one single phase (gas) and two phases (gas-liquid), as well as, in one stage and stages of packed beds “Pb”. For this purpose, a 3-D CFD model presenting a vertical packed column of one single stage and two stages of packed beds is established using Ansys-Fluent. The CFD simulations are compared with the available experimental data and empirical models. The results are made to determine the pressure drop of an air flow in one single stage of packed bed in order to check that Ergun equation is correctly verified. Then, an air-water flow in two stages of packed bed is carried out. Moreover, the effect of porosity, packing size and mixture velocity on pressure drop of gas-liquid flow are investigated numerically. As results, pressure drop was found to be less than 40% lower in two stage packed column than in one stage. This study provides the understanding of the pressure drop in order to extract informations for the reactors and to ensure that CFD can be used as a useful tool for modelling.