An absorber must recover 99% ammonia from an air-ammonia feed stream, using water as the absorbent liquid. The ammonia content in air is 20 mol%. The temperature of the absorber is maintained at 30 °C by cooling coils and the pressure is 1 atm. a) What is the minimum flow rate of water?
b) For a water flow 40% higher than the minimum value, how many global transfer units based on the gas phase are needed?