Abstract: In a method for desulfurizing flue gas generated in coal combusting plants, the coal is burned in the presence of a dry additive material, such as CaCO optionally in presence of recycled cold flue gas whereby additive material which has not reacted is discharged together with the flue gas from the firing space and is separated together with the ashes in dust filters. The relative moisture of the flue gas is increased before entering the dust filter so that the sulfur compounds in the flue gas react to a greater extent with the additive material in the dust filters. The device for practicing this method comprises a heat exchanger and/or an injection cooler arranged streamup of the flue gas filtering installation.

Abstract: Flue gas from a coal-fired combustion to which a dry sulfur-binding additive is supplied, after cooling is subjected to filtration to remove additive ash therefrom. According to the invention, cooled additive ash is fed to at least a portion of the flue gas to reduce the temperature thereof approximately to the water dewpoint, thereby promoting the sulfur-binding reaction.