= . 22.5-6. Absorption of Ammonia in a Packed Tower. A gas stream contains 4.0 mol % NH3 and its ammonia content is reduced to 0.5 mol % in a packed absorption tower at 293 K and 1.013 105 Pa. The inlet pure-water flow is 68.0 kg mol/h and the total inlet gas flow is 57.8 kg mol/h. The tower diameter is 0.747 m. The film mass-transfer coefficients are k a a = 0.0739 kg mol/s m3 mol frac and k a mol/s m. mol frac. Using the design methods for dilute gas mixtures, do as follows: a. Calculate the tower height using ka. b. Calculate the tower height using K 4. Ans. (az = 2.362 m (7.75 ft) m