Quantification of Entrainment Using an Optical Inline Probe

Abstract

In distillation and absorption processes, entrainment above trays or packings reduces stage and column efficiency. A modified version of the optical multimode online probe enables a seminal insight and, thus, quantification of entrained droplets on various axial and radial positions. A purging mechanism inhibits precipitation of droplets on the front lenses, while telecentric optics and illumination provide distance-independent and precise imaging of entrained droplets between two valve trays. Experiments were performed in a DN 450 cold flow (air-water) test rig. The results were compared with noninvasive phase Doppler anemometry data.

Experimental Investigation of Droplet Entrainment in the Feed Section of Distillation Columns

“…A suggestion for future investigations is measuring the droplet size above the feed inlet devices in the column. Either an optical method or the laser method should be applied.…”

“…Lichti et al. with their optical probe measured the entrainment droplet size in a tray column . Brunazzi et al.…”

Digital Extraction Column: Measurement and Modeling Techniques

“…Furthermore, measurements in bubble columns allow a determination of the interfacial area , even in slurry bubble columns with the presence of solid particles, such as catalysts . While all these fluid systems contain a liquid continuous phase, modifications in probe design also enable spray detection , . In conclusion, there are several measurement techniques that can be used to detect droplets in a continuous phase, having different advantages and disadvantages as summarized in Tab.…”

Impact of weir design on entrained liquid in tray columns

“…Observing entrained liquid in the free space enables tracking the hydraulic reaction of liquid and gas on changes in the operation parameters and column design. Latest developments in camera technique and computing capacity facilitate the acquisition of multiple measurement points with large image samples in a short time 32 . A prediction of the integral captured entrainment based on the local measurements of the free entrainment represents a unique feature, as it allows to evaluate free and captured entrainment and by that to understand the entrainment mechanism as a whole 33 .…”