Influence of rewetting method on soybean behaviour during fluidized bed drying, experimental and simulation study

Abstract

Soybean was used in fluidized bed drying tests, after rehydrating to 22% [d.b.] by adopting two rehydration methods: the first is by adding distilled water, while the second is by adopting the gravimetric method. Drying of soybeans was performed using a fluidized-bed dryer under air temperature conditions between 40 °C and 60 °C and with an air mass flowrate between 0.010 kg s⁻¹ and 0.034 kg s⁻¹. Luikov's model was adopted to predict the heat and mass transfer phenomena during fluidization process. The experimental results showed that the soybean re-humidified by the gravimetric method gave the highest drying rate of 0.0098 (kg water.kg⁻¹s⁻¹) and the highest germination rate of 88%, with a minimum percentage of cracked grains of 7%. It was concluded from this study that the gravimetric method allows better rewetting of soybeans; while drying of these seeds can be carried out, with minimal loss, at a temperature of 40 °C in fluidized bed dryers.