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US 5,683,666 AGranted
Method for the removal of sulfur dioxide and nitrogen oxides for a gaseous stream
AssigneeDravo Lime Company
InventorDaniel W. Berisko
Life of this patent
Estimating the term…
Abstract
A process for the simultaneous removal of sulfur dioxide and nitrogen oxides from a gaseous stream uses a sorbent containing magnesium ions and sulfite ions for sulfur dioxide removal and a metal chelating agent for nitrogen oxides removal, with the production of an amine disulfonate salt, such as potassium amine disulfonate, as a purified saleable by product.
Claims10
A method for the removal of sulfur dioxide and nitrogen oxides from a gaseous stream said method comprising:
- contacting said gaseous stream in a wet scrubbing unit with an aqueous scrubbing mediumcontaining magnesium ions and sulfite ions at a pH of 5.5 to 7.0, in the presence of a metal chelating agent, whereby solid sulfites, dissolved sulfites and hydroxylaminedisulfonate are produced in said aqueous medium;
- removing a portion of aqueous medium containing magnesium ions, solid sulfites, dissolved sulfites and hydroxylaminedisulfonate from said wet scrubbing unit;
- separating said solid sulfites from said portion of aqueous medium;
- basifying said portion of aqueous mediumto a pH of 10.0 or above to convert said magnesium ions to a magnesium hydroxide precipitate;
- separating said magnesium hydroxide precipitate, so formed, from said aqueous medium;
- adding an oxidizing agent to said portion of aqueous medium to convert dissolved sulfites to sulfates which precipitate from said aqueous medium;
- separating said sulfates, so formed, from said aqueous medium;
- and
- adding a sulfate salt to said portion of aqueous medium to produce an amine disulfonate salt which precipitates from said aqueous medium.
6 more elements
A method for the removal of sulfur dioxide and nitrogen oxides from a gaseous stream said method comprising:
- contacting said gaseous stream in a wet scrubbing unit with an aqueous scrubbing medium containing magnesium ions and sulfite ions at a pH of 5.5 to 7.0, in the presence of ferrous ethylenediaminetetraacetic acid, whereby solid sulfites, dissolved sulfites and hydroxylaminedisulfonate are produced in said aqueous medium;
- removing a portion of aqueous medium containing magnesium ions, solid calcium sulfites, dissolved sulfites and hydroxylaminedisulfonate from said wet scrubbing unit;
- separating said solid calcium sulfites from said portion of aqueous medium;
- basifying said portion of aqueous mediumto a pH of 10.0 or above to convert said magnesium ions to a magnesium hydroxide precipitate;
- separating said magnesium hydroxide precipitate, so formed, from said aqueous medium;
- adding an oxidizing agent to said aqueous medium to convert dissolved sulfites to sulfates which precipitate from said aqueous medium;
- separating said sulfates, so formed, from said aqueous medium;
- and
- adding a potassium sulfate to said aqueous medium to produce a potassium amine disulfonate salt which precipitates from said aqueous medium.
6 more elements
Dependencies are inferred from the claim text.