Patent ID: 7704472

Claim:
An air pollutant control system comprising: a denitration apparatus that reduces nitrogen oxide in flue gas discharged from an industrial boiler, and injects hydrogen chloride into the flue gas to oxidize mercury; a desulfurization apparatus that absorbs sulfur oxide in flue gas thus denitrated; a stack from which gas thus desulfurized is discharged outside; a hydrogen chloride vaporizer that produces hydrogen chloride with a supply of concentrated hydrochloric acid; and a neutralization tank where at least one of dilute hydrochloric acid discharged from the hydrogen chloride vaporizer and the concentrated hydrochloric acid is neutralized with an alkali agent, wherein chloride resulting from such neutralization is supplied to a fuel, and then burned in the industrial boiler to produce hydrogen chloride in flue gas, and, together with hydrogen chloride sprayed, the mercury is reduced.