Process for removal of NO.sub.x and SO.sub.x oxides from waste gases with chloric acid
AssigneeOlin Corporation
InventorsJerry J. Kaczur, Steven A. Iacoviello, Budd L. Duncan
Life of this patent
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Abstract
A process for removing NO.sub.x oxides and SO.sub.x oxides from gaseous streams contacts the gaseous stream with an aqueous solution of chloric acid. The process of the invention removes sulfur oxides and nitrogen oxides from waste gas streams without producing inorganic salts. In addition, the use of chloric acid provides improved oxidation of NO and SO.sub.2. The process can be operated to treat "dirty" gas streams containing particulates and compounds which may poison or contaminate NO.sub.x removal systems employing catalysts.
Claims17
A process for removing either NO.sub.X oxides, or SO.sub.X oxides or mixtures thereof from a gaseous stream comprising:
- (a) contacting a gaseous stream containing either NO.sub.X oxides, or SO.sub.X oxides or mixtures thereof in an oxidizing scrubber with an aqueous oxidation solution consisting essentially of chloric acid or a mixture of chloric acid and alkali metal chlorate at about 0.degree. C. to about 100.degree. C. for sufficient time to oxidize any oxidizable species of said NO.sub.X oxides and SO.sub.X oxides, said chloric acid feed concentration being from about 0.05% to about 50% by weight of said aqueous oxidization solution and said aqueous oxidation solution being substantially free of other cationic and anionic impurities;
- (b) separating said oxidized gaseous stream from said aqueous oxidation solution which contains nitric acid, sulfuric acid or mixtures thereof found from said oxidation of said oxidizable NO.sub.X and SO.sub.X oxides;
- (c) contacting said oxidized gaseous stream in an aqueous scrubber with an aqueous solution selected from the group consisting of water, an aqueous solution of an alkaline compound or an aqueous solution of a sulfur-based reducing agent for sufficient time to remove substantially all of the NO.sub.X oxides, SO.sub.X oxides or mixtures thereof from said oxidized gaseous stream;
- and
- (d) separating said oxidized gaseous stream which is substantially free of said NO.sub.X oxides, SO.sub.X oxides or mixtures thereof from said aqueous solution.
Dependencies are inferred from the claim text.