Process Flow

An FGD plant removes poisonous gas components, such as sulfur dioxide (SO₂), contained in the untreated flue gas discharged from a coal, oil or other carbon-derived fuel fired boilers,. FGD plants are also very efficient at removing particulate matter. Furthermore, FGD plants produce useful by-products, such as gypsum, which can be recycled into gypsum board or building cement. Thus FGD plants play an important role in improving the environmental performance of power stations and refineries whilst also producing useful products which can be sold to market.

Schematic process flow

Limestone is suspended in water to form a limestone slurry which is injected into an absorber which scrubs the flue gas. The limestone slurry contacts with the flue gas and absorptive removal of sulfurous acid gas occurs, inducing the subsequent production of gypsum (CaSO₄·2H₂O) through use of the oxidation air sparger. Particulate matter in the flue gas are also captured and removed in the absorber leading to a double environmental benefit and a cleaner flue gas stream which is then emitted to atmosphere via the plant stack.

SO₂ Absorbtion Chemical Equation;
SO₂ + CaCO₃ + 1/2O₂ + 2H₂O→CaSO₄·2H₂O + CO₂