Flue-gas desulphurization (FGD) is a set of technologies used to remove sulfur dioxide (SO₂) from exhaust flue gases of fossil-fuel power plants and from the emissions of other sulfur oxide emitting processes such as waste incineration petroleum refineries, cement and lime kilns.

With ever more stringent environmental regulations limiting SO₂ emissions - in Europe, the current threshold value for SO₂ in the EU is 200 mg/Nm³ - SO₂ is being removed from flue gases by means of an industrial process through the addition of
absorbents. Socrematic offers various processes and technologies for flue-gas desulphurization

• Wet scrubbing using various type of reagents such as NaOH, ZnO, Na₂CO₃

• Regenerative flue gas desulfurization using hydrogen peroxide (H₂O₂) with sulfuric acid (H₂SO₄) production

• Flue gas desulfurization using limestone (CaCO₃) with gypsum production or also using Ca(OH)₂

The wet process has become the main method of flue gas desulphurisation in large, fossil-fuelled power plants. In the wet process, the flue gases are steam-saturated with the absorbent in aqueous solution. Substances such as ammonia or sodium sulphite are used as absorbents.

The use of lime or limestone slurry (wet limestone scrubbing) is also widespread. The uncleaned flue gas is sprayed in a scrubber tower (absorber tower) with a mixture of water and limestone (scrubbing slurry), whereby most of the sulphur dioxide is bonded by chemical reaction.

Most FGD systems employ two stages: one for fly ash removal and a second stage for SO₂ removal. In wet scrubbing systems, the flue gas normally passes first through a fly ash removal device, either an electrostatic precipitator or a baghouse, and then into the SO₂-absorber. However, in dry injection or spray drying operations, the SO₂ is first reacted with the lime, and then the flue gas passes through a particulate control device.

Socrematic offers a series of robust and proven wet scrubbing technologies for flue gas desulfurization:

WATSOx® scrubber: our zero waste treatment solution using hydrogen peroxide with diluted sulfuric acid as bleed.

DynaWave® scrubber: equipped with multiple reverse jets, designed for handling dirty hot gasses, the DynaWave® scrubber technology is an excellent fit for complying with stringent regulation

Reither® scrubber: high-efficiency, variable venturi wet scrubber for separation of sub-micron level particles

Hybrid Reither® scrubber: combining jet-washer and venturi technology for treating submicronic dusts with low pressure drops