Save the date: November 4, 2026 – 4:45 p.m. ‘Superheated steam for energy efficient drying and agglomeration in a fluidized bed’

Aim

The use of superheated steam as a drying medium has seen limited industrial applications due to high equipment costs, maintenance requirements, and increased process complexity. In fluidized bed operations, however, superheated steam offers significant potential for energy‑efficient food processing. The intensive particle movement characteristic of fluidized beds enables enhanced heat and mass transfer, while the steam atmosphere can be exploited not only for drying but also for particle agglomeration, allowing targeted improvement of functional product properties such as wettability and dispersibility. In this study, the processes drying and agglomeration using superheated steam in a fluidized bed was systematically analysed and benchmarked against a conventional hot‑air process.

Method

Experiments were conducted in a pilot‑scale fluidized bed unit. Using a microcrystalline cellulose as a model, process parameters required to achieve a low residual moisture content were determined for both drying media, and comprehensive energy balances were established. In addition, the model material was used to investigate the agglomeration potential of superheated steam. Material properties such as residual moisture, bulk density and solubility in water were analysed.

Results

Operating the process in a pure steam atmosphere with systematic recovery of available waste heat as well as the latent heat of condensation reduced the specific energy consumption of that of a conventional hot air drying process. The additional integration of vapor compression further enhanced energy efficiency. The steam atmosphere was also used to agglomerate particles, resulting in a high wettability and solubility in water compared to the reference.

Conclusion

These results demonstrate that superheated steam drying and agglomeration in a fluidized bed is a novel and scalable process strategy for the sustainable production of functional food powders, such as instant beverage formulations, combining substantial energy savings with enhanced product functionality. Beyond the energy efficiency, the superheated steam atmosphere inherently provides thermal microbial reduction, thereby enabling preservation‑free processing and supporting clean‑label product concepts.

Please note: The lecture will be given in German language.