Calcium desulfurization is a common and widely used flue gas desulfurization technology, which mainly includes limestone-gypsum method and lime method.

Limestone-Gypsum Method:

Principle: Limestone is used as a desulfurizer and made into slurry. In the absorption tower, the limestone slurry reacts chemically with sulfur dioxide in the flue gas to produce calcium sulfite. Calcium sulfite is further oxidized into calcium sulfate (gypsum).

Chemical reaction formula:

Absorption reaction:CaO + SO₂ + 1/2H₂O → CaSO₃·1/2H₂O

Oxidation reaction:CaSO₃·1/2H₂O + 1/2O₂ + 3/2H₂O → CaSO₄·2H₂O

Advantage:

The technology is mature, the operation is reliable, the desulfurization efficiency is high, the absorbent resources are abundant, the cost is relatively low, and the by-product gypsum can be comprehensively utilized.

Lime method

Principle:Lime (CaO) is used as a desulfurizing agent to make lime slurry, which reacts with sulfur dioxide to form calcium sulfite, which is then oxidized to calcium sulfate.

Chemical reaction formula:

Absorption reaction:CaCO₃ + SO₂ + 1/2H₂O → CaSO₃·1/2H₂O + CO₂

Oxidation reaction:CaSO₃·1/2H₂O + 1/2O₂ + 3/2H₂O → CaSO₄·2H₂O

Advantage:The reaction speed is fast and the desulfurization efficiency is high.

Calcium desulfurization is widely used in the power, steel, chemical and other industries.