Terahertz pulsed imaging as a new method for investigating the liquid transport kinetics of α-alumina powder compacts

Mohammed Al-Sharabi, Daniel Markl, Vincenzino Vivacqua, Prince Bawuah, Natalie MacLean, Marian Bentley, Andrew P.E. York, Michele Marigo, Karen Huang, J. Axel Zeitler*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

10 Citations (Scopus)
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Investigating the liquid transport kinetics of solid catalysts is of great importance for gaining a better understanding of the manufacturing and performance of such catalysts during reaction upon contact with the liquid. Terahertz pulsed imaging (TPI) coupled with a newly designed flow cell was used to quantify the rate of water ingress into α-alumina pellets with a range of different porosities. A wide range of compaction forces (cold compaction, 7–58 kN) and sintering conditions (no firing and sintering at 1200 and 1300 °C) was investigated to explore the optimal pellet microstructure, i.e. mechanically strong but sufficiently porous for fast liquid transport kinetics. The results confirm that both the microstructure characteristics, particularly porosity, as well as the surface properties, i.e. wettability, influence the liquid transport kinetics. Fitting the TPI penetration rates with a power law shows that the type of observed mass transport characteristics is consistent with Darcy flow. The Lucas–Washburn equation was used to calculate the hydraulic radius based on the transport data. In summary, the results demonstrate that TPI has great potential to study the liquid transport kinetics of porous ceramic catalysts and catalyst supports and that can comfortably quantify transport processes at rates of 250 μm s−1 and beyond in such substrates for better quality control and optimised design and performance of such materials.

Original languageEnglish
Pages (from-to)386-397
Number of pages12
JournalChemical Engineering Research and Design
Early online date21 Nov 2020
Publication statusPublished - 31 Jan 2021


  • liquid transport
  • microstructure
  • modelling
  • porous media
  • terahertz pulsed imaging
  • α-Alumina


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