Flue Gas Desulphurisation
Double Alkali Regeneration System

During scrubbing reaction,SO2 reacts with Sodium Sulphite to form Bisulphite. Which then do not take further part in chemical reaction. Hence it needs regeneration. In our Double Alkali regeneration system, bleed stream from scrubber recirculation tank contains Sodium Sulfite, Sodium Bisulfite and Sodium Sulphate are reacted with lime under very specific operating conditions like pH, conductivity, mixing, reaction time etc most condusive for regeneration of caustic. The Sodium Bisulfite can be regenerated chemically. The Calcium Sulfite, Calcium Sulphate produced in the reaction are precipitated and withdrawn from the system. The Bisulfite is converted back to Sulfite. The regenerated liquid is then taken back to the scrubbing system. The regenerated sodium salts mostly offset the need for new sodium salts. Gypsum can be produced as an option.