Method for combined removal of mercury and nitrogen oxides from off-gas streams
AssigneeThe United States of America as represented by the United States Department of Energy
InventorsMarshall H. Mendelsohn, C. David Livengood
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Abstract
A method for removing elemental Hg and nitric oxide simultaneously from a gas stream is provided whereby the gas stream is reacted with gaseous chlorinated compound to convert the elemental mercury to soluble mercury compounds and the nitric oxide to nitrogen dioxide. The method works to remove either mercury or nitrogen oxide in the absence or presence of each other.
Claims20
A process for removing elemental mercury from a gaseous stream comprising:
- a) contacting a vaporized oxidizing agent with the gaseous stream for a time and at a temperature sufficient to form water soluble nitrogen and mercury-containing compounds, wherein the oxidizing agent comprises chloric acid and an alkaline metal chlorate;
- and
- b) removing the water soluble compounds from the gas stream.
A method for simultaneously removing elemental mercury and NOx from a flue gas stream containing other constituents, the method comprising:
- g) vaporizing an aqueous solution containing an oxidizing agent, wherein the oxidizing agent is present in the aqueous solution at a concentration of between 0.001 and 5 weight percent;
- and
- h) contacting the vaporized oxidizing agent with the gaseous stream for a time and at a temperature sufficient to form water-soluble nitrogen- and mercury containing compounds;
- and
- i) removing the water-soluble compounds.
A method to simultaneously remove mercury and nitric oxide from flue gas, the method comprising:
- n) vaporizing an oxidizing agent;
- o) contacting the vaporized oxidizing agent with the flue gas for a time and at a temperature sufficient to create water soluble mercury and nitrogen-containing compounds;
- and
- c) removing the water soluble compounds from the gas stream, wherein the water soluble compounds are removed using aqueous scrubbers employing alkaline moieties.
A method to simultaneously remove mercury and nitric oxide from flue gas, the method comprising:
- a) contacting a vaporized oxidizing agent with the gaseous stream for a time and at a temperature sufficient to form water soluble nitrogen and mercury-containing compounds, wherein the oxidizing agent is selected from the group consisting of an alkali metal hydroxide, and alkaline earth metal hydroxide, an alkali metal carbonate, an alkaline earth metal carbonate and mixtures thereof;
- and
- b) removing the water soluble compounds from the gas stream.
A process for removing elemental mercury from a gaseous stream comprising:
- a) contacting a vaporized oxidizing agent with the gaseous stream for a time and a temperature sufficient to form water soluble nitrogen and mercury-containing compounds, wherein the oxidizing agent is selected from the group consisting of:
- chloric acid, chloric acid and an alkaline metal chlorate, chlorine dioxide or combinations thereof;
- and
- b) removing the water soluble compounds from the gas stream.
Dependencies are inferred from the claim text.