METHOD OF SCRUBBING AND DEVICE FOR REMOVAL OF SULFUR OXIDES FROM COMBUSTION PRODUCTS Russian patent published in 2000 - IPC

FIELD: cleaning of effluent flue gases from sulfur oxides, particularly, methods and devices for washing of sulfur oxides (SO_x) out of effluent flue gases with aqueous limestone slimes. SUBSTANCE: in single-pass open tower-type counterflow scrubbers for limestone wet scrubbing of gases, discharge velocity of effluent flow is considerably increased, while value of liquid/gas ratio and treatment time in reaction vessel are reduced. Specified above merits arise from use of entrainment separator of improved design, nature of sprayers arrangement and interval between time and also from application of hydrocyclone for separation of gypsum formed as byproduct, and return of finer particles of limestone back to process. Limestone is ground to highly dispersed particles, for instance, sizing approximately 8 mcm or less with more than 99 wt.% of particles sizing less than 44 mcm; and obtained product is added to slime for gas scrubbing which is brought in contact with effluent flow containing SO_x. Reactivity of slime for scrubbing of gases is maintained even at low pH values by continuous operation of hydrocyclone due to which value of molar ratio of calcium- and sulfur-containing substances is ensured high approximately 1.3:1, and simultaneously low content of chlorides and nonreactive commercial materials is maintained. Hydrocyclone removes large particles of calcium sulfate and provides for obtaining of recirculating flow of finely dispersed calcium carbonate and nonreactive solid material. The flow, if required, is washed to maintain needed low content of chlorides and nonreactive solid materials. EFFECT: higher productive and economic efficiency with respect to capital investments and maintenance costs. 32 cl, 5 dwg