Abstract: A method of removing acid gases from hot flue gases wherein the flue gas is fed through a pipe (3) and up through a tubular reaction chamber (1) having a diverging bottom wall (2) which causes a rapid reduction in axial velocity. Further flue gas is introduced tangentially through a pipe (5) to produce a rising swirling stream of flue gas, in which a powdery absorption agent, that has been introduced through an inlet (4), is entrained. The agent reacts with the acid gas to produce powdery reaction products which are subsequently removed in separators (7,7').

Abstract: Sulfur oxides and other acid gases are removed from hot flue gases by dispersing and suspending an absorption agent and water, preferably Ca(OH).sub.2 suspended in water, in a rising stream of hot gas at the lower part of a reaction chamber, where the hot gases are subjected to a rapid reduction in velocity. Sulfur oxides and other acid gases are absorbed on and reacted with the absorption agent in the presence of evaporating water producing a dry powder which is separated from the flue gas in a particle precipitator and partially recirculated to the reaction chamber.