7,000 lb/h of wet, pulverized, clay particles with 27% moisture (dry basis) at 15°C and 1 atm enter a flash dryer where they are dried to a moisture content of 5% (dry basis) with a co-current flow of air that enters at 525°C. The dried solids exit at the air wet-bulb temperature of 50°C, while the air exits at 75°C. Assuming a reasonable value for the specific heat of clay, calculate:
(a) The flow rate of air in lb/h (dry basis).
(b) The rate of evaporation of moisture.
(c) The heat-transfer rate in Btu/h.