A dryer for comestible herbs was tested in lab scale at the ZHAW facility.

The aim of the dryer is to increase the quote of renewable energy during the drying process by reaching 100% of renewable thermal energy, and at the same time to ensure a high quality of the dried products.

The herbs are dried in a standard drying chamber by air flowing from the bottom through the perforated floor. The innovation is the treatment of the air, which is flowing is a closed loop and its humidity is removed by contact with the Thermo-Chemical Fluid (TCF), in this case NaOH-solution.

The scope of the tests was to understand and to characterise the conditions that can be achieved in the plant and to optimise the setup of the plant. Furthermore, the dried herbs were analysed to ensure a standard or higher quality.

Dryer photo

Dryer schematic