Experiments and modelling of the microwave assisted convective drying of canola seeds

The heat and mass transfer that occurred during the drying of a 1:1 mixture of two canola seed varieties using combined microwave (MW) and convective drying was studied. A coupled mathematical model was adapted to simulate the physical process. The product was re-wetted to an initial moisture content (IMC) of 18% w.b. and then dried in a microwave oven under MW density of 0.5 W g(-1), 1 W g(-1) and 2 W g(-1). Results show that the maximum drying rate increased from 4.3 x 10(-5) to 6.8 x 10(-5) kg [water] kg(-1) [grain w.b.] s(-1) in the convective drying as the temperature of the inlet air increased from 40 to 60 degrees C, but it remained constant when MW was combined with convective hot-air. The use of microwave energy during drying of canola seeds resulted in faster drying when coupled with convective drying at low relative humidity. (C) 2015 IAgrE. Published by Elsevier Ltd. All rights reserved.