Method for removing acidic components including nitrogen oxide from waste gases
AssigneeBackau-Walther Aktiengesellschaft
InventorsHorst Bechthold, Heinz J. Fischer, Wolfgang Schulte
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Abstract
A method of simultaneously removing SO.sub.x and NO.sub.x from waste gases. Using a known desulfurization process the waste gases free of the acidic components are contacted with an oxidizing agent in the gas phase for the oxidation of the oxygen of nitrogen contained in the waste gases. The formed NO.sub.2 is absorbed in a subsequent absorbing stage under previous addition of NH.sub.3 and the thereby obtained absorbing product is oxidized to form ammonium nitrate in a subsequent oxidation stage with atmospheric oxygen and then reconveyed into the desulfurization process.
Claims14
A method of removing acid components of waste gases which are emitted from a furnace or other combustion device and comprise oxides of sulfur and nitrogen, comprising the steps of
- (a) contacting the waste gases with a first absorbing fluid comprising NH.sub.3 in a first absorbing stage to produce from the sulfur oxides a first solution which is removable from the waste gases and comprises sulfate and sulfite salts including ammonium sulfate and ammonium sulfite;
- (b) oxidizing the first solution to produce an oxidized first solution predominantly comprising sulfate salts;
- (c) contacting the waste gases, after removal of the first solution, with an oxidizing agent to produce from the oxides of nitrogen a gaseous stream containing nitrogen dioxide;
- (d) contacting the gaseous stream with a second absorbing fluid containing NH.sub.3 in a second absorbing stage to produce from the nitrogen dioxide a second solution which is removable from the gaseous stream and comprises nitrate and nitrite salts including ammonium nitrate and ammonium nitrite;
- (e) oxidizing the second solution to produce therefrom an oxidized second solution predominantly containing nitrate salts;
- and
- (f) wherein the oxidized solutions are dried.
Dependencies are inferred from the claim text.