Spherical alumina catalyst particles with 30 percent moisture and an average size of 300 m are dried

Spherical alumina catalyst particles with 30 percent moisture and an average size of 300 μm are dried in a batch fluidized bed with air entering at 250°F, a superficial velocity of 1.2 ft/s, and a humidity of 0.016 lb H₂O/lb dry air. 

(a) If the settled bed depth is 4 ft and the initial solids temperature is 80°F, estimate the exit temperature of the air. 

(b) What is the temperature of the solids during the constant-rate period?

(c) What is the maximum drying rate, in pounds of water removed per hour per pound of catalyst?