Process for removing sulfur dioxide from flue gas

摘要

The sepn. of SO2 from waste gas comprises scrubbing with sea water in an absorption tower. The liquid sump in the tower is aerated to convert bisulphite to bisulphate and the liquid is discharged into a sec. reaction tank, where it is mixed with fresh sea water for sulphate formation and neutralisation. The pH of the liquid discharged from the tower is monitored and deviations from a theoretical value in the pH 4.0-5 range are determined and used to control addn. of sea water directly to the sump or a liquid stream recycled from the sump into the absorption zone of the tower.