Amine gas treating is used to remove H2S and CO2 from sour gas for environmental reasons. In the absorber unit, an amine solution absorbs H2S and CO2 molecules from the feed gas in order to "sweeten" the upflowing gas stream.
Gradually, the amine becomes "rich" (i.e. saturated) with absorbed H2S and loses scrubbing efficiency. The rich amine must be sent to a regenator unit (typically comprised of a stripper with a reboiler) to be converted back into fresh "lean" amine for recycling into the absorber unit.
The lean amine produced by the regenerator should be validated by a continuous H2S loading measurement to ensure there are no problems with the stripper. Watching breakthrough levels in the lean amine allow for prompt response to regenerator problems and prevent treating efficiency losses from sending ineffective amines to the absorber.