1. Limestone Preparation System

Limestone is crushed and ground into fine powder, then mixed with water to form slurry.

The slurry is stored in a preparation tank before being pumped to the absorber.

Limestone grinding mill

2. Flue Gas Pre-treatment

Boiler flue gas passes through a dust collector (ESP or bag filter) to remove particulates.

Optionally, a GGH (Gas-Gas Heater) adjusts flue gas temperature before desulfurization.

3. Absorber Tower

Flue gas flows upward while limestone slurry is sprayed downward.

SO₂ is absorbed and reacts with CaCO₃ to form calcium sulfite.

With oxidation air supplied, calcium sulfite is converted to gypsum (CaSO₄·2H₂O).

4. Gypsum Processing

The gypsum slurry is separated in a hydrocyclone/thickener.

The filtrate is recycled, while gypsum is dewatered and discharged as a by-product.

Gypsum grinding machine

5. Clean Flue Gas Discharge

The treated gas passes through a demister to remove droplets.

It is then released through the stack (possibly reheated via GGH to reduce visible plume).