Contact

Prof. Dr. Markus Schubert

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

Fluid dynamics and mass transfer in sandwich packings

Sub-project: Characterization of fluid dynamics using ultrafast X-ray tomography

Similar to random or conventional structured packings, sandwich packings are employed to promote large contact between gaseous and liquid phases in separation columns operated in a counter-current mode. Such sandwich packings consist of two corrugated sheet layers with different specific surface area, arranged alternately inside the column. As a result, bubbly flow evolves in the hold-up layer. Compared to conventional packed columns, the interaction between the involved phases is strongly intensified, in particular in the bubbly flow area and the evolving froth regime. This leads to higher separation efficiency of the column, further accompanied by reduced energy consumption.

Principle of the sandwich packing - combination of packing layers with different specific surface area
Figure 1: Principle of the sandwich packing - combination of packing layers with different specific surface area causing characteristic flow patterns (film, froth and bubbly flow).

Within the scope of the DFG-funded project, the fluid dynamic behavior of sandwich packings is comprehensively studied at HZDR. For this purpose, experimental studies are carried out in a 100 mm diameter column operated with water and air in the counter-current mode. The ultrafast X-ray tomography permits noninvasive imaging of the complex and highly dynamic flow patterns inside the packing. Crucial parameters such as liquid holdup, gas-liquid interfacial area and froth height are determined. Furthermore, pressure sensors precisely measure the axial pressure gradient along the column height, thereby revealing information about the transitions zones between the evolving flow configurations.

The gathered data of the fluid dynamics will be correlated and implemented in a modelling approach to provide tools for the design of columns with sandwich packings and for the prediction of their separation efficiency.

Packed column with ultrafast X-ray tomograph and gas-liquid distribution during the measurements
Figure 2: Packed column with ultrafast X-ray tomograph (left), time averaged gas-liquid distribution(right).
(Video - gas-liquid distribution during the measurements)

Cooperation

  • Paderborn University, Chair of Fluid Process Engineering

Funding

Deutsche Forschungsgemeinschaft (DFG, HA3088/10-1)

References

  • M. Schubert, A. Bieberle, F. Barthel, S. Boden, U. Hampel
    Advanced tomographic techniques for flow imaging in columns with flow distribution packings
    Chemie Ingenieur Technik 83, 7, 979-991 (2011)
  • A. Janzen, M. Schubert, F. Barthel, U. Hampel, E. Y. Kenig
    Investigation of dynamic liquid distribution and hold-up in structured packings using ultrafast electron beam X-ray tomography
    Chemical Engineering and Processing 66, 20-26 (2013)
  • S. Flechsig, Ö. Yildirim, E. Y. Kenig
    Sandwich Packings: State of the Art
    ChemBioEng Reviews 3, 174-185 (2016)
  • J. Sohr, A. Litzka, M. Schubert, S. Flechsig, E. Y. Kenig, U. Hampel
    Untersuchung heterogener Strömungsmuster in Anstaupackungen mittels ultraschneller Röntgentomographie: Methode und Validierung
    Jahrestreffen der ProcessNet Fachgruppe Fluidverfahrenstechnik, 8-10. März 2017, Köln (2017)
  • S. Flechsig, J. Sohr, M. Schubert, U. Hampel, E. Y. Kenig
    Anwendung von Anstaupackungen bei der CO2-Absorption in wässrigen Aminlösungen
    Jahrestreffen der ProcessNet Fachgruppe Fluidverfahrenstechnik, 8-10. März 2017, Köln (2017)