Hydrodynamics and mass transfer phenomena in counter-current packed column at elevated pressures

Abstract

The aim of this study is to determine mass transfer parameters such as interfacial area a and volumetric liquid side mass transfer coefficient k L a during gas–liquid absorption in a packed column according to pressure within the range 0.1–1.3 MPa. A preliminary hydrodynamic study was carried out in order to characterize gas and liquid flows according to the operating pressure. The residence time distribution method shows that fluids flows can be modeled as plug flow with axial dispersion. In contrast to the liquid flow, an effect of pressure on the gas flow has been observed. The axial dispersion coefficient of the gas increases with pressure. These results allow modeling of the gas–liquid absorption in a packed column with or without chemical reaction and at elevated pressures. The basic equations defining the hydrodynamic profile of the gas and liquid films are completed by the terms describing mass transfer coupled with an irreversible chemical reaction in the liquid phase. The numerical resolution of the system of equations obtained has allowed the study of the influence of pressure on the interfacial area a. This parameter increases with pressure. The same result has been observed with the volumetric liquid side mass transfer coefficient k L a. The coefficient k L is independent of pressure.