Alkaline Scrubber

In an alkaline scrubber, acid-forming components are collected via neutralization using a base as scrubbing liquid.  This leads to the formation of salts, which can eventually be reprocessed. The drained water is purified and discharged into the sewer network.

Alkaline dosage occurs on the basis of pH control. The pH for an alkaline scrubber is normally kept between 8.5 and 9.5. The pH cannot be set very high, due to increased alkaline usage at higher pHs due to absorption of CO₂ in the water. From a pH above 10, the dissolved CO₂ will be present in the water as carbonate, whereby alkaline use will increase sharply. The calcium carbonate will also precipitate on the packing, whereby the pressure drop will increase. To avoid this,  softened water must be used for alkaline scrubbers.