Flue gas (sometimes called exhaust gas or stack gas) is the gas that emanates from combustion plants and which contains the reaction products of fuel and combustion air and residual substances such as particulate matter (dust), sulfur oxides, nitrogen oxides, and carbon monoxide. The composition of flue gas depends upon the composition and properties of the fuel being combusted. FGD is a system that reduces the SOx in flue gas through chemical treatment and converting the captured SOx into a by-product such as a Gypsum or Calcium Sulphate or Sulphuric Acid depending upon the type of mechanism used.
A flue gas desulfurization technique known as SNOx , uses catalytic reactions to clean flue gases of nitrogen oxides (NOx) and particulates, as well as sulfur dioxide. The major types of large-scale, power plant FGD systems include spray towers, spray dryers and dry sorbent injection systems.
Hence, FSD Technique remove the harmful gases and particulate matters from Combustion Plants and thus prevent the air to become polluted.