Absorption of oxygen in countercurrent multistage bubble columns—III Viscoelastic liquids. Comparison of systems with high viscosity

Abstract

The volumetric mass transfer coefficients, k La , were measured by a steady state method in the first stage of a multistage countercurrent column 20 cm in diameter. Perforated plate trays with different bore hole diameters and free cross sectional area were employed. The height of the stage was varied. Viscoelastic fluids (PAA) solutions) were used as media. In general k La increases with increasing superficial gas velocity, with decreasing bore hole diameter and free cross sectional area of the perforated plate trays as well as with decreasing concentration and viscosity. With increasing height of the bubbling layer k La diminishes. This effect is lower with an increase of PAA concentration. A qualitative comparison of the rheologically corresponding media indicates that under similar conditions PAA solutions yield the highest, and the glycerol solution the lowest k La values. With increasing specific power input k La becomes larger. At constant power input the highest k La is attained with the smallest bore hole diameter of the trays for CMC and PAA solutions. For glycerol no such effect was found.