According to our experimental results, it is found that it has a good combination of drying curves in spite of
changes in air conditions and the kind of treatment.
Thyme drying curves show the same declining rate.
However, the effect of the drying volume flow rate at a fixed temperature is remarkable.
Thus, the highest drying volume flow rate Dv2 (300 m3/h) leads to the reduction of the dry moisture content and the drying time.
In addition, at this flow, the pretreatment have no significant effect on the dry moisture content whatever the concentration of citric acid.
However, drying at a low volume flow rate Dv1 (150m3/h) increases the duration of drying and reserves higher dry moisture content. Besides, the influence of citric acid concentration is observed on the drying kinetics.