Prediction in constant-rate drying region. A granular insoluble solid material wet with water is being dried in the constant-rate period in a pan 0.61 m ´ 0.61 m and the depth of material is 25.4 mm. The sides and bottom are insulated. Air flows parallel to the top drying surface at a velocity of 3.05 m/s and has a dry bulb temperature of 60 °C and wet bulb temperature of 29.4 °C. The pan contains 11.34 kg of dry solid having a free moisture content of 0.35 kg H2O/kg dry solid, and the material is to be dried in the constant-rate period to 0.22 kg H2O/kg dry solid. a) Predict the drying rate and the time in hours needed. b) Predict the time needed if the depth of material is increased to 44.5 mm.