Chapter 12. Absorption and Stripping

Up to now we have talked almost entirely about distillation. There are other unit operations that are very useful in the processing of chemicals or in pollution control. Absorption is the unit operation where one or more components of a gas stream are removed by being taken up (absorbed) in a nonvolatile liquid (solvent). In this case the liquid solvent must be added as a separating agent. Absorption is one of the methods used to remove CO₂ from natural gas and flue gasses so that the CO₂ is not added to the atmosphere where it helps cause global warming (Socolow, 2005).

Stripping is the opposite of absorption. In stripping, one or more components of a liquid stream are removed by being vaporized into an insoluble gas stream. Here the gas stream (stripping agent) must be added as a separating agent.