Question Statement:
A vegetable with 70% moisture (wet basis) is to be dried in a countercurrent dryer to give a product with 5% moisture (wet basis). The feed rate to the dryer is 0.15 kg s⁻¹. The drying medium consists of air at 100 °C containing water vapour with a partial pressure of 1.0 kPa. The air leaves the dryer at 40 °C and is 70% saturated. The system works under a total pressure of 101.3 kPa. The vapour pressure of water that saturates air at 40 °C is 7.4 kPa. Molecular weight of water and air may be taken as 18 and 29 respectively. The humidity (kg of water vapour / kg of dry air) of the outlet air is
Options:
- (A) 0.0027
- (B) 0.0172
- (C) 0.0335
- (D) 0.0483