A dryer is removing 100 lbs water per hour from the material being dried. The air entering the dryer has a dry-bulb temperature of 180°F and a wet-bulb temperature of 110°F. The air leaves the dryer at 140°F. A portion of the air is recirculated after mixing with room air having a dry-bulb temperature of 75°F and a relative humidity of 60% a. (20%) Determine the quantity of air required by the dryer. b. (15%) Determine the recirculation rate. c. (15%) Determine the load on pre-heater if it is assumed that the system is adiabatic. Neglect the heat-up of the feed and of the conveying equipment.