Process for dry removal of sulfur dioxide from combustion gases

Claim 1

In a process for removing sulfur dioxide from combustion gases of a steam-generating system that comprises a boiler, an economizer, an air preheater, a precipitator, and a stack, by reaction of the sulfur dioxide with dry particles of reactive lime-bearing materials, the improvement comprising: diverting the said combustion gases containing SO 2 , prior to their passing said precipitator, from their normal flow path to a reaction chamber, retaining said gases in said reaction chamber with fine particles of dry reactive, lime-bearing materials for a reaction time longer than 2 seconds and not exceeding about 15 seconds while well and continuously mechanically agitating said gases and said particles whereby to maintain said particles in suspension, then passing said gases with said suspended particles from said reaction chamber to a settling chamber wherein the major portion of the solid particles are removed from the gases, said fine particles of dry, reactive lime-bearing materials comprising a product containing aggregates of fine particles obtained by grinding together a dry mixture of fresh, fine, reactive lime-bearing material and solid particles removed from said gases in said settling chamber, and then passing the said gases back into said normal flow path.