An absorber is to be designed to reduce the concentration level of a mercaptan pollutant in an exhaust stream from 5.0 to 0.3 mol %. A nonvolatile, mercaptan-free solvent stream will be fed to the top of the tower and will flow countercurrent to 0.236 m3 /s of exhaust gas stream. The tower is to operate at 293 K and 1.013×105 Pa; at these conditions, the equilibrium data for the mercaptan-solvent system are as follows:
Determine the height of packing required if the solvent leaves the bottom of the tower containing 3.05 mol % mercaptan, the overall mass-transfer capacity coefficient, KYa, equals 40.0 mol/m2.s. ?YA, and the cross-sectional area of the tower is 0.2 m2.