Packed bed absorption column: Hydrodynamics and mass transfer

Abstract

This paper presents the results of the determination of the hydrodynamic characteristics and mass transfer in the pilot plate absorption column. The experimental values of the pressure drop in the countercurrent flow of air and water through the column were obtained. The graphic dependence of the pressure drop of air per unit height of the layer of packing (ÄP/h) on the apparent air velocity (Ug) through the dry charge was shown to be in the form of a quadratic function. From the graphical function which shows the dependence of the pressure drop per unit height of the layer of filling (ÄP/m) on the apparent air velocity during the countercurrent flow of the phases (water and air), three fields of the interaction of the phases were observed: a) the area of low load, at low apparent air velocities, b) the area of high load, at higher air velocities, and c) the flooding area, when the liquid completely fills the cavities and the working gas in them starts bubbling. The overall mass transfer coefficient (Kg) of the air-CO2-water system depends on the flow rate of the gaseous phase and the composition of the starting gas mixture (air-CO2). With the increase in the total gas flow rate, with a constant composition of the starting gas mixture and constant fluid flow, the overall mass transfer coefficient increases. Increasing the amount of CO2 in the starting gas mixture at a constant flow rate of fluid and a constant ratio of the molar flow of the inert in the liquid and the gas-phase (L'/G') decreases the overall mass transfer coefficient.

Keywords

• absorption column
• pressure drop
• mass transfer coefficient