Consider a vapor stream composed of 90 mole% air and 10 mole% acetone. This stream is fed into an absorption column operating at 300 kPa and which has 20 stages. The solvent used to remove acetone from air is pure water. You can change the solvent to feed flow-rate ratio. This Demonstration calculates the vapor and liquid composition profiles inside the column as well as the temperature and molar flow rates. The calculation is rigorous since it solves the full MESH (mass, equilibrium, summation, and enthalpy) equation. It is possible to obtain a percent recovery of acetone equal to 100% since acetone is readily soluble in water. Comparison with Aspen HYSYS shows excellent agreement (HYSYS and Mathematica results are indicated by the open circles and solid squares, respectively).