Advanced Tomographic Techniques for Flow Imaging in Columns with Flow Distribution Packings

Abstract

Design and optimization of separation units, e.g., distillation and absorption columns with flow distribution packings, require detailed knowledge about the internal flow conditions and their impact on the process behavior. This in turn calls for suitable measuring techniques, which can give a detailed insight into such devices, especially for studies on a laboratory and pilot scale. Traditional instrumentation, such as compartment-type liquid collectors installed below packings, or distributed temperature, pressure and conductivity probes, often falls too short if detailed knowledge on flow conditions is required. This concerns especially local liquid holdup, liquid maldistribution, liquid films thickness, wetting of the packing surface, or bubble size and droplet distribution at trays. Advanced imaging techniques, such as tomography, have found only marginal attention in investigations of separation columns with structured and modern dumped flow distribution packings, mostly due to limited spatial and temporal resolution but also due to prevailing technological problems encountered in such applications. In this study, the potentials and limits of some of the most recently emerged tomographic imaging modalities for multiphase flows have been investigated and reviewed, i.e., ultra-fast X-ray tomography, high-resolution gamma-ray tomography, wire-mesh sensor techniques, and X-ray microtomography with respect to a possible application in separation columns with flow distribution packings.

Measurement of Fluid Dynamics in Random Packings Using High‐Resolution Computed Tomography

“…Insbesondere die Bestimmung des Benetzungsverhaltens der Flüssigkeit auf den Füllkörpern und die Bestimmung der Stoffaustauschfläche sind nur schwer möglich. Schubert et al zeigen in einer Übersicht ebenfalls die Einsatzmöglichkeiten tomographischer Messmethoden für die Untersuchung von Packungskolonnen auf.…”

Applications of tomography in bubble column and trickle bed reactors

“…Thus, the application of MRI to reactors with metallic internals has been challenging. X-ray and g-ray CT are potentially advantageous in this regard (Bazer-Bachi, Haroun, Augier, & Boyer, 2013;Bieberle et al, 2013;Boyer & Fanget, 2002;Schubert et al, 2011). CT techniques have also been used in an analogous manner to the MRI techniques discussed above to characterize the distribution of gas and liquid in structured packing materials such as Katapak-SP 12 (Aferka, Crine, Saroha, Toye, & Marchot, 2007) and Mellapak 752Y (Roy et al, 2005).…”

“…Owing to the wealth of literature on the topic, this review cannot summarize all of the work in the area. The interested reader is referred to earlier reviews for further discussion of the importance of tomography in understanding multiphase reactors (Joshi, Tabib, Deshpande, & Mathpati, 2009;Al-Dahhan, Larachi, Dudokovi c, & Laurent, 1997;Boyer, Duquenne, & Wild, 2002;Chaouki, Larachi, & Dudukovic, 1997;Dudukovic, 2002;Heindel, 2011;Mudde, 2010a;Reinecke & Mewes, 1996;Schubert, Bieberle, Barthel, Boden, & Hampel, 2011). The chapter concludes with an outlook for expected future developments of tomographic imaging in these systems and some sources of further information.…”

Quantifizierung der Trenneffizienz einer strukturierten Packung mittels numerischer Simulation

“…Um das Setup zur Simulation der Fluiddynamik zu validieren, wurde am Helmholtz‐Zentrum Dresden‐Rossendorf (HZDR) eine mit Silikonöl belastete strukturierte Packung tomographisch untersucht. Die dabei verwendete Messmethodik ist in Schubert et al beschrieben. Für den Vergleich der Flüssigkeitsverteilung in Experiment und Simulation werden horizontal durch ein Packungselement verlaufende Schnittbilder herangezogen.…”