Patent ID: 8382470

Claim:
A method of combusting sulfurous fuel in a fluidized bed boiler plant, said method comprising the following steps of: (a) forming a fluidized bed of particles in a furnace of a fluidized bed boiler plant, into which bed sulfurous fuel, CaCO 3 -containing sulfur-binding agent and combustion air are introduced, whereby the sulfurous fuel is combusted and generates flue gases, and the CaCO 3 -containing sulfur-binding agent calcinates to CaO and binds SO 2 formed in the combustion of the sulfurous fuel; (b) guiding the generated flue gases from the furnace into a flue gas channel; (c) circulating a heat exchange medium in heat exchange tubes of a heat exchanger arranged in the flue gas channel; (d) recovering heat energy from the flue gases into a the heat exchange medium circulating in the heat exchange tubes of the heat exchanger arranged in the flue gas channel; (e) separating and collecting CaO-containing ash from the fluidized bed boiler plant; (f) adjusting the temperature of the heat exchanger in the flue gas channel so that an aqueous solution of acid, generated from the flue gases, condenses on the outer surfaces of the heat exchange tubes; (g) collecting the aqueous solution of acid that is condensed on the outer surfaces of the heat exchange tubes; and (h) neutralizing the collected aqueous solution by mixing it in a mixing vessel with the ash collected in step (e), in order to produce a dry, solid material.