Fluid dynamics and separation efficiency of column trays

Distillation is the pioneer separation technology in chemical process industries. Around half of the columns in the world are fitted with cross-flow trays due to their versatility. Since these columns are expensive in terms of cost and energy consumption, an accurate determination of their separation efficiency is a necessity to improve their performance by design modification and revamping, as well as to reduce the extra trays added during the design phase to account for the uncertainties. The extent of liquid mixing and flow patterns are significant for the trays to perform satisfactorily. The occurrence of liquid channeling, bypassing, retrograde flow, recirculation and stagnant regions deteriorate their separation performance accordingly.

With the recent advances in measurement and imaging techniques, it is possible to obtain the flow and the mixing patterns in tray columns at high spatial and temporal resolution. For this purpose, a column fitted with two sieve trays of 800 mm diameter and a wire-mesh sensor (52 × 64) is constructed at HZDR.



In addition, the development of new modeling methodologies, to quantify the tray separation efficiency, parallel to aforementioned advancements is also ongoing. Until then, the existing theoretical approaches will be used for adjudging the performance of the tray undergoing flow maldistribution.



Funding

Deutscher Akademischer Austauschdienst e. V. (DAAD, 91563198)

References

  • V. Vishwakarma, M. Schubert, U. Hampel
    Assessment of separation efficiency modeling approaches pertaining to flow and mixing patterns on distillation trays
    Chemical Engineering Science, submitted (2017)
  • M. Schubert, M. Piechotta, M. Beyer, E. Schleicher, U. Hampel, J. Paschold
    An imaging technique for characterization of fluid flow pattern on industrial-scale column sieve trays
    Chemical Engineering Research and Design 111, 138-146 (2016)
  • V. Vishwakarma, M. Schubert, U. Hampel
    Effect of flow non-idealities on tray efficiency
    Jahrestreffen der ProcessNet Fachgruppe Fluidverfahrenstechnik, 8-10. März 2017, Köln (2017)
  • V. Vishwakarma, M. Schubert, U. Hampel
    Distillation tray efficiency modeling: a forgotten chapter
    Jahrestreffen der ProcessNet Fachgruppe Fluidverfahrenstechnik, 16-17. März 2016, Garmisch-Partenkirchen (2016)

URL of this article
https://www.hzdr.de/db/Cms?pOid=51852


Contact

Dr. Markus Schubert

m.schubertAthzdr.de
Phone: +49 351 260 2627