FLUE GAS DE-SULPHURIZATION (FGD) PLANT
All over the world, more than 75% of electricity is being generated from thermal power plant and coal contains sulphur in the range of 0.3%-1% depending upon origin location. Whereas, in some regions suphur content is up to 1.5%. In thermal power plants, sulphur (present in coal) reacts and form sulphur dioxide (SO2), which is very harmful to the environment. So to save our environment, many countries like US and European countries have stringent regulations that discharge of sulphur dioxide (SO2) should be less than 0.05%. For this, power plants are installing Flue Gas Desulphurisation (FGD) unit.
Processes of Flue Gas Desulphurization (FGD) Technology:
- Limestone slurry is sprayed on the incoming flue gas. The sulphur dioxide gets absorbed. The limestone and sulfur dioxide react as follows :
CaCO3 H2O 2SO2 ----> Ca 2 2HSO3- CO2
CaCO3 2HSO3- Ca 2 ----> 2CaSO3 CO2 H2O
- A process improvement called forced oxidation which further oxidizes the calcium sulphite to Calcium sulphate in the following reactions
CaSO3 H2O ½ O2 ----> CaSO4 H2O