Sulfate control in ammonia flue gas desulfurization

Abstract

Abstract BUILDUP OF SURFACE IONS IN A FLUE GAS DESULFURIZATION SYSTEM EMPLOYING AN AQUEOUS AMMONIACAL ABSORBENT IS PREVENTED BY REDUCING A PORTION OF THE SULFATE TO SULFUR DIOXIDE. SULFUR DIOXIDE, IS REMOVED FROM FLUE GAS BY ABSORPTION IN AN AQUEOUS SOLUTION OF AMMONIUM SULFITE OR AMMONIA. SOME OXIDATION OF TETRAVALENT SULFUR TO THE HEXAVALENT STATE TAKES PLACE. AT LEAST A PORTION OF THE ABSORBER EFFLUENT SOLTUION IS REGENERATED BY ACIDIFICATION WITH AMMONIUM BISULFATE TO LIBERATE SULFUR DIOXIDE AND TO FORM AN AQUEOUS AMMONIUM SULFATE-AMMONIUM BISULFATE SLURRY. THIS SLURRY IS INTRODUCED INTO A DECOMPOSITION ZONE WHERE A MAJOR PORTION OF THE SALT CONTENT IS DECOMPOSED INTO AMMONIUM BISULFATE AND AMMONIA, AND A MINOR POR- TION INTO A GAS MIXTURE COMPRISING AMMONIA, NITROGEN, SULFUR DIOXIDE AND STEAM. THE AMMONIUM BISULFATE THUS PRODUCED FURNISHES THE BISULFATE USED FOR LIBERATION OF SULFUR DIOXIDE. THE GAS MIXTURE FORMED IN DECOMPOSITION IS USED TO AMMONIATE A SECOND PORTION OF THE ABSORBER EFFLUENT SOLUTION, AND THEREBY PRODUCE FRESH ABSORBENT SOLUTION.

Inventors

• 👤 Albert B Welty Jr

Bibliographic Details