Experimental study of the effect of viscous media on the hydrodynamic characteristics of a rotating packed bed

Abstract

A simple and robust quantitative approach was proposed to determine liquid entrainment and flooding in rotating packed beds (RPBs), which complements visual observations and pressure drop measurements. The RPB was modified by installing a hydrocyclone at the gas outlet to quantify the amount of liquid ejected. The original technique previously introduced in the literature for air-water systems, was explored using a viscous mixture to determine the flooding onset. This approach eliminates bias in the criteria used to define the onset of liquid entrainment and flooding in RPBs. The method also minimizes inaccuracies introduced by unexplained pressure drops during flooding in RPBs. In the method, flooding occurred when entrainment exceeds 8% of the total liquid inlet flow rate. The study used a water-glycerine mixture with viscosities of 13 and 30 mPa.s and found that the entrainment of viscous liquids in RPBs begins with a small volume of liquid droplets, progressing to moderate volumes of liquid-film entrainment. The quantitative approach used in this study enhances the reliability of fundamental data essential for the design and scale-up of RPBs. This study is an indispensable guide for using RPBs in high-viscosity mass transfer and separation processes.