Wet grain at 70°F has a moisture content of 10%. It is to be dried in a rotary dryer to a final moisture content of 1%. The dryer operates at atmospheric pressure and dries 10 tons/day of wet grain. Air is used to achieve the drying, with the air flowing counter currently to the wet grain. Air enters at 225°F (dry bulb) and has a wet bulb temperature of 110°F. It exits with a wet bulb temperature of 125°F. Assume that there is no heat loss from the dryer, that the grain discharges at 110°F, and that its specific heat is 0.18 BTU/(lbm*°F).

a) Sketch this process and label all known variables;

b) Determine the humidity of the entering and exiting air if the exit air is saturated;

c) Calculate the water removal in pounds per hour;

d) Calculate the daily product output in pounds per day;

e) Calculate the heat input to the dryer.