GB1352435A - Method and apparatus for purifying flue gases - Google Patents

Abstract

1352435 Purifying flue gas G & W H CORSON Inc 19 June 1971 28859/71 Headings C5G and G10A The sulphur content in the flue gas from a fossil fuel burning furnace producing fly ash is reduced by introducing a stream of freshly formed hydrated alkaline earth hydroxide into the flue gas at a temperature of 1200-2400‹F and maintaining the additive in contact with the flue gases for 0.1-5 sees. Quick lime, magnesian lime or dolomitic lime is metered by conveyer 12 to a water tank 13, and fed to a pressure hydrator 16. The hydrated lime is fed direct to an oil or coal-fired boiler furnace 32, at a position where the temperature is 1200- 2400‹F. The finely divided reactive oxides formed by the rapid dissociation and the hydrated lime at this temperature combines with the sulphur content of the flue gases and the fly-ash to give complex sulphites in the ash which is collected at 34. The additive feed is at a rate such as to produce a desired low sulphur content in the gases, and the fly ash provides useful material for load-bearing soil stabilization, mortar or concrete. The additive may be mono- or dihydrated dolomitic lime, and has an average particle size less than 5 microns, and a surface area greater than 30,000 sq. cms./gm.