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 sulphur 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 Plant (FGD) or unit.