Influence of Viscosity on Liquid Flow Inside Structured Packings

Abstract

In this study, X-ray computer tomography and light-induced fluorescence were applied to investigate the morphology of liquid flow inside structured packings. Fluid dynamic parameters such as liquid holdup and wetted surface were determined to study the effect of the variation of viscosity and liquid load. Flow patterns inside the packing were identified and categorized. Liquid film thickness and its distribution were analyzed on single sheets. For both methods, the measured holdup values are in good agreement, despite differences in the techniques of measurement. For the flow patterns and their relative contribution, as well as mean liquid film thickness, a strong dependency on the varied parameters was found. Furthermore, the density function of film thickness distribution changed characteristically with liquid load and viscosity. The complementary use of tomography and optical assessment allowed an improved insight into flow phenomena and the observed interdependency of physical, geometric, and operational parameters.

Geometry and viscosity effects on separation efficiency in distillation

“…Hence, the fraction of packing surface, actively wetted with liquid and therefore the interfacial CHERD-1811; No. of Pages 12 chemical engineering research and design x x x ( 2 0 1 5 ) xxx-xxx 7 (2011) and Bradtmöller et al (2015) are considered, especially loads below 5 m 3 /(m 2 h) result in a major decrease of wetted surface. It may be assumed this loss of wetted surface accounts for the increase of HETP in case of CB/EB.…”

Three-dimensional simulation of rivulet and film flows over an inclined plate: Effects of solvent properties and contact angle

“…Structured packing offers superior performance [3] with a large surface area per unit volume for mass transport and a high absorption efficiency while minimizing pressure drop [4]. Structured packed columns are also widely used in other chemical processing technologies such as distillation and liquid-liquid extraction [5][6][7]. The accurate design of such columns requires knowing essential hydrodynamic characteristics, such as, pressure drop and liquid holdup of the packing element [8].…”

“…Consequently, an increase in solvent viscosity may lead to enhanced liquid holdup and increased pressure drop in the packed column. Recently, experimental studies [6] have shown a complex dependency of liquid holdup in structured packings on solvent viscosity, in conjunction with liquid load. Specifically, for a highly viscous liquid (µ ≥ 20mPas) the film flow liquid holdup showed non-monotonic variation, i.e.…”

Modular and Cost-Effective Computed Tomography Design

“…Already by 1980, the design of an isotopic CT scanner for two-phase flow investigations was presented and was successfully evaluated [ 13 ]. Further CT scanners were presented over the next few decades [ 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 ] and were used to reveal phase distributions in large-scale devices with internals [ 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 ]. To obtain non-superimposed images from CT scans, radiographic projections from different angular positions from the object of investigation are required.…”