Chapter 1, Problem 1.4P

A mixture of 25 percent ammonia gas and 75 percent air (dry basis) is passed upward through a vertical scrubbing tower, to the top of which water is pumped. Scrubbed gas containing 0.5 percent ammonia leaves the top of the tower, and an aqueous Solution containing 10 percent ammonia by weight leaves the bottom. Both entering and leaving gas streams are saturated with water vapor. The gas enters the tower at $37.8°\text{C}$ and leaves at $21.1°\text{C}$. The pressure of both streams and throughout the tower is 1.02 atm gauge. The air-ammonia mixture enters the tower at a rate of $28.32m^3/min$, measured as dry gas at $15.6°\text{C}$ and 1 atm. What percentage of the ammonia entering the tower is not absorbed by the water? How many cubic meters of water per hour are pumped to the top of the tower?

Answers: 1.5%; $2.71m^3/h$