Ninety-five percent of the acetone vapor in an 85 vol% air stream is to be absorbed by countercurrent contact with pure water in a valve-tray column with an expected overall tray efficiency of 50%. The column will operate essentially at 20°C and 101 kPa pressure. Equilibrium data for acetone-water at these conditions are:
Mole percent acetone in water 3.30 7.20 11.7 17.1
Acetone partial pressure in air, torr 30.00 62.80 85.4 103.0
Calculate:
(a) The minimum value of L'/ V', the ratio of moles of water per mole of air.
(b) The number of equilibrium stages required using a value of L'/ V' of 1.25