A textile finishing process involves drying a fabric that has been treated with a volatile solvent. The drying process involves evaporation of solvent and removal of solvent vapor by air. The wet fabric entering the dryer contains 50% solvent. Solvent-free air enters the dryer at a rate of 8 kilograms per kilogram of dry (solvent-free) fabric. The drying process is 96% efficient (i.e., 96% of the entering solvent is removed from fabric).
(a) Calculate the percentage of solvent in the dried fabric by weight.
(b) What is the concentration of solvent in the dryer exhaust (in g/m3) if the exhaust is at 80 degrees C and 1 atm? The solvent has a molecular weight of 86.