A method for cleaning flue gas from a combustion plant, the hcl, so2 and hg, and flue gas cleaning system

摘要

A method for cleaning flue gas from a combustion plant, the hydrogen chloride (hcl, sulfur dioxide so₂ and mercury hg contains,in the case of which the flue gas in at least one washing stage with a scrubbing liquid with a ph - value of 0 to 8 is brought into contact, andin the washing fluid washed out divalent mercury hg (ii) in the form of hg (ii) - compounds, at least of mercuric chloride hgcl₂, it is released, wherein the hg (ii) - connections with the aid of ligands l are formed,characterized in thatthe amounts of the ligands and of the dissolved hg (ii) in the washing fluid be adjusted so that the ratio m of their concentrations [l] and [hg (ii)] is greater than or equal to a minimum value mm is: the minimum value mm empirically in a function of a target value for the concentration of the mercury in the pure gas and of the type of ligands is determined.