Process for removing mercury vapor from flue gas

• US 20020114749A1
• Filed: 12/22/2000
• Published: 08/22/2002
• Est. Priority Date: 12/22/2000
• Status: Abandoned Application

• Current Assignee: General Electric Company
• Original Assignee: General Electric Company
• Inventors: Cole, Jerald Alan
• Application Number:
  US09/745,014
• Publication Number:
  US 20020114749A1
• Time in Patent Office: Days
• US Class Current: 423/210
• CPC Class Codes: B01D 53/64 Heavy metals or compounds thereof, e.g. mercury

Abstract

Process for removing elemental mercury vapor from flue gas which comprises contacting the flue gas with a gaseous oxidizing agent at a gaseous oxidizing agent region to render the elemental mercury vapor more easily oxidized. The flue gas is then subjected to oxidation at a point downstream of the gaseous oxidizing agent region to oxidize the elemental mercury vapor and thereby render it more easily removed.

Claims

1. A process for removing elemental mercury vapor from flue gas which comprises:

contacting the flue gas with a gaseous oxidizing agent at a gaseous oxidizing agent region to render the elemental mercury vapor more easily oxidized; and

subjecting the flue gas to oxidation at a point downstream of the gaseous oxidizing agent region to oxidize the elemental mercury vapor and thereby render it more easily removed.

2. A process according to claim 1, wherein the gaseous oxidizing agent is selected from the group consisting of Cl₂, the oxides of chlorine, H₂O₂, HOCl, compounds of chlorine, F₂, Br₂, I₂ and Kr₂ and their compounds, and sulfur species.

3. A process according to claim 2, wherein the sulfur species is selected from H₂S, SO₃, H₂SO₄, CH₃SH and CH₂S.

4. A process according to claim 1, wherein the flue gas contains HCl in a range of I to 30 ppm, elemental mercury vapor in a range of I ppb to I ppm, and the gaseous oxidizing agent is Cl₂.

5. A process according to claim 4, wherein the amount of Cl₂ contacted with the flue gas is in the range of 1 to 30 ppm.

6. A process according to claim 1, wherein the elemental mercury vapor is contacted with free radicals.

7. A process according to claim 1, wherein the elemental mercury vapor is subjected to an electric discharge.

8. A process according to claim 7, wherein the flue gas is subjected to the electric discharge at a temperature of less than 300°

C.

9. A process according to claim 8, wherein the temperature at which the flue gas is subjected to the electric discharge is in the range of 100°

C. to 50°

C.

10. A process according to claim 6, wherein the oxidation of the elemental mercury vapor occurs within an electrostatic precipitator.

11. A process according to claim 1, wherein the oxidation of the elemental mercury vapor is initiated by electromagnetic radiation.

12. A process according to claim 11, wherein the electromagnetic radiation is visible or ultraviolet light.

13. A process according to claim 1, wherein the oxidation of the elemental mercury vapor is initiated by microwave energy.

15. A process according to claim 14, wherein the electrical discharge is generated by a microwave corona.

16. A process according to claim 14, wherein the electrical discharge is a short pulse spark discharge.

14. A process for removing elemental mercury vapor from flue gas which comprises:

contacting the flue gas with a gaseous oxidizing agent selected from the group consisting of Cl₂, an oxide of chlorine, H₂O₂, and HOCl at a gaseous oxidizing agent region to render the elemental mercury vapor more easily oxidized; and

subjecting the flue gas to an electrical discharge at a point downstream of the gaseous oxidizing agent region to oxidize the elemental mercury vapor and thereby render it more easily removed.