Mathematical modelling of the Drying Curves of hemispherical solids

Advancing the chemical engineering fundamentals

Transport Phenomena in Porous/Granular Media (T2-7P)

Dr Susana Simal
Universitat de les Illes Balears
Chemistry
Ctra. Valldemossa, km 7.5 Palma de Mallorca, 07122. Balears
Spain

Ing M. Carme Garau
Universitat de les Illes Balears
Chemistry
Ctra. Valldemossa km. 7.5. 07122. Palma de Mallorca. Balears
Spain

Dr Jaume Cañellas
Universitat de les Illes Balears
Chemistry
Ctra. Valldemossa km. 7.5. 07122. Palma de Mallorca. Balears
Spain

Dr José Bon
Universitat Politécnica de València
Food Technology
Cno. Vera s/n. 46071. Valencia.
Spain

Keywords: drying, hemisphere, modelling, diffusion, apricot

Conventional air-drying is the most frequently used drying operation in food and chemical industry. The drying kinetics are greatly affected by air temperature and material characteristic dimension, while all other process factors usually exhibit less influence. The drying curves of halved and deseeded apricots at different temperatures (from 50 to 90ºC) have been evaluated and a diffusional model, solved by a finite elements method, has been proposed to simulate the drying kinetics.
The effect of the external resistance on the mass transfer curves was important and therefore, modelling was only accurate when this effect was taken into consideration. Due to the geometry of the system considered, a hemisphere loosing water only through the flat section, the mass transfer coefficient (kc) could not be correctly estimated through an empirical correlation.
Only the identification of this coefficient identified from the experimental results, allowed an accurate simulation, decreasing the mean relative error from 12.33.8% when kc was calculated through the Pasternak and Gauvin correlation, to 2.91.0% when kc was identified.

Presented Monday 17, 13:30 to 15:00, in session Transport Phenomena in Porous/Granular Media (T2-7P).