Granted Patent B2

US 8,951,487 · App. 13/920,658 · Granted Feb 10, 2015

Abstract

Claims (68)

1. A method, comprising:

generating from a mercury-containing feed material a mercury-containing gas stream comprising vapor-phase elemental mercury and a vapor-phase halogen;

passing the mercury-containing gas stream through a scrubber to remove at least a portion of the vapor-phase halogen and/or a halogen-containing derivative thereof and form a halogen-containing scrubbing medium and a treated gas stream; and

removing the halogen from the halogen-containing scrubbing medium to form a treated scrubbing medium for recycle to the scrubber and a removed halogen and/or halogen-containing material,

wherein the halogen in the removed halogen and/or halogen-containing material comprises iodine and wherein the scrubber is a wet or dry scrubber.

2. The method of claim 1 , wherein the scrubber removes at least most of the vapor-phase halogen from the gas stream and wherein the scrubber removes at least most of an acid gas from the gas stream.

3. The method of claim 1 , wherein at least most of the halogen on the halogen-containing scrubbing medium is removed as the removed halogen and/or halogen-containing material.

4. The method of claim 1 , wherein the scrubber is a wet scrubber and is capable of removing one or more of HCl, HBr, and HF from the gas stream.

5. The method of claim 1 , wherein the scrubber is a wet scrubber and wherein the halogen is removed from the halogen-containing scrubbing medium by one or more of an ion exchange resin, solvent extraction, adsorption, absorption, precipitation, and membrane filtration.

6. The method of claim 1 , wherein a concentration of the vapor-phase halogen in the treated gas stream is no more than about 25 ppm.

7. The method of claim 1 , wherein the vapor-phase halogen is iodide.

8. The method of claim 1 , wherein the vapor-phase halogen comprises bromide.

9. The method of claim 1 , wherein the mercury-containing feed material is coal, wherein the mercury-containing gas stream is formed by combusting coal, and wherein the vapor-phase halogen is formed from a native halogen-content of the coal.

10. The method of claim 1 , wherein the mercury-containing feed material is coal, wherein the mercury-containing gas stream is formed by combusting coal, and wherein the vapor-phase halogen is formed from a halogen-containing additive combusted with the coal.

11. The method of claim 1 , wherein the mercury-containing feed material is coal, wherein the mercury-containing gas stream is formed by combusting coal, and wherein the vapor-phase halogen is introduced into the gas stream downstream of a coal combustion zone.

12. A method, comprising:

generating from a mercury-containing feed material a mercury-containing gas stream comprising vapor-phase elemental mercury and a vapor-phase halogen, the vapor phase halogen comprising iodine;

passing the mercury-containing gas stream through a scrubber to remove at least a portion of the vapor-phase halogen and/or a halogen-containing derivative thereof and form a halogen-containing scrubbing medium and a treated gas stream; and

removing the halogen from the halogen-containing scrubbing medium to form a treated scrubbing medium for recycle to the scrubber and a removed halogen and/or halogen-containing material,

wherein the halogen is removed from the halogen-containing scrubbing medium by one or more of membrane separation, precipitation, adsorption, and/or absorption,

wherein the halogen-containing scrubbing medium is contacted with an oxidant to assist halogen removal.

13. A method, comprising:

generating from a mercury-containing feed material a mercury-containing gas stream comprising vapor-phase elemental mercury and a vapor-phase halogen comprising iodine;

passing the mercury-containing gas stream through a scrubber to remove at least a portion of the vapor-phase halogen and/or a halogen-containing derivative thereof and form a halogen-containing scrubbing medium and a treated gas stream; and

removing the halogen from the halogen-containing scrubbing medium to form a treated scrubbing medium for recycle to the scrubber and a removed halogen and/or halogen-containing material,

wherein the halogen can oxidize elemental mercury in the gas stream and further comprising:

recycling the removed halogen and/or halogen-containing material to the generating step, whereby the vapor-phase halogen is derived from the removed halogen and/or halogen-containing material.

14. The method of claim 13 , further comprising regenerating the removed halogen and/or halogen-containing material prior to recycle.

15. A method, comprising:

generating from a mercury-containing feed material a mercury-containing gas stream comprising vapor-phase elemental mercury and a vapor-phase halogen comprising iodine;

passing the mercury-containing gas stream through a scrubber to remove at least a portion of the vapor-phase halogen and/or a halogen-containing derivative thereof and form a halogen-containing scrubbing medium and a treated gas stream; and

removing the halogen from the halogen-containing scrubbing medium to form a treated scrubbing medium for recycle to the scrubber and a removed halogen and/or halogen-containing material,

wherein the scrubber removes at least most of the vapor-phase halogen from the gas stream and wherein the scrubber removes at least most of an acid gas from the gas stream.

16. A method, comprising:

generating from a mercury-containing feed material a mercury-containing gas stream comprising vapor-phase elemental mercury and a vapor-phase halogen comprising iodine;

passing the mercury-containing gas stream through a scrubber to remove at least a portion of the vapor-phase halogen and/or a halogen-containing derivative thereof and form a halogen-containing scrubbing medium and a treated gas stream; and

removing the halogen from the halogen-containing scrubbing medium to form a treated scrubbing medium for recycle to the scrubber and a removed halogen and/or halogen-containing material,

wherein the scrubber is a wet scrubber and is capable of removing one or more of HCl, HBr, and HF from the gas stream.

17. A method, comprising:

generating from a mercury-containing feed material a mercury-containing gas stream comprising vapor-phase elemental mercury and a vapor-phase halogen comprising iodine;

passing the mercury-containing gas stream through a scrubber to remove at least a portion of the vapor-phase halogen and/or a halogen-containing derivative thereof and form a halogen-containing scrubbing medium and a treated gas stream; and

removing the halogen from the halogen-containing scrubbing medium to form a treated scrubbing medium for recycle to the scrubber and a removed halogen and/or halogen-containing material,

wherein a concentration of the vapor-phase halogen in the treated gas stream is no more than about 25 ppm.

18. A method, comprising:

generating from a mercury-containing feed material a mercury-containing gas stream comprising vapor-phase elemental mercury and a vapor-phase halogen;

passing the mercury-containing gas stream through a scrubber to remove at least a portion of the vapor-phase halogen and/or a halogen-containing derivative thereof and form a halogen-containing scrubbing medium and a treated gas stream; and

removing the halogen from the halogen-containing scrubbing medium to form a treated scrubbing medium for recycle to the scrubber and a removed halogen and/or halogen-containing material,

wherein the vapor-phase halogen is iodide.

19. A method, comprising:

generating from a mercury-containing feed material a mercury-containing gas stream comprising vapor-phase elemental mercury and a vapor-phase halogen;

passing the mercury-containing gas stream through a scrubber to remove at least a portion of the vapor-phase halogen and/or a halogen-containing derivative thereof and form a halogen-containing scrubbing medium and a treated gas stream; and

removing the halogen from the halogen-containing scrubbing medium to form a treated scrubbing medium for recycle to the scrubber and a removed halogen and/or halogen-containing material,

wherein the vapor-phase halogen comprises iodide and bromide.

20. A method, comprising:

generating from a mercury-containing feed material a mercury-containing gas stream comprising vapor-phase elemental mercury and a vapor-phase halogen comprising iodine;

passing the mercury-containing gas stream through a scrubber to remove at least a portion of the vapor-phase halogen and/or a halogen-containing derivative thereof and form a halogen-containing scrubbing medium and a treated gas stream; and

removing the halogen from the halogen-containing scrubbing medium to form a treated scrubbing medium for recycle to the scrubber and a removed halogen and/or halogen-containing material,

wherein the mercury-containing feed material is coal, wherein the mercury-containing gas stream is formed by combusting coal and wherein the vapor-phase halogen is formed from a native halogen-content of the coal.

21. A method, comprising:

generating from a mercury-containing feed material a mercury-containing gas stream comprising vapor-phase elemental mercury and a vapor-phase halogen comprising iodine;

passing the mercury-containing gas stream through a scrubber to remove at least a portion of the vapor-phase halogen and/or a halogen-containing derivative thereof and form a halogen-containing scrubbing medium and a treated gas stream; and

removing the halogen from the halogen-containing scrubbing medium to form a treated scrubbing medium for recycle to the scrubber and a removed halogen and/or halogen-containing material,

wherein the mercury-containing feed material is coal, wherein the mercury-containing gas stream is formed by combusting coal, and wherein the vapor-phase halogen is formed from a halogen-containing additive combusted with the coal.

22. A method, comprising:

generating from a mercury-containing feed material a mercury-containing gas stream comprising vapor-phase elemental mercury and a vapor-phase halogen comprising iodine;

passing the mercury-containing gas stream through a scrubber to remove at least a portion of the vapor-phase halogen and/or a halogen-containing derivative thereof and form a halogen-containing scrubbing medium and a treated gas stream; and

removing the halogen from the halogen-containing scrubbing medium to form a treated scrubbing medium for recycle to the scrubber and a removed halogen and/or halogen-containing material,

wherein the mercury-containing feed material is coal, wherein the mercury-containing gas stream is formed by combusting coal, and wherein the vapor-phase halogen is introduced into the gas stream downstream of a coal combustion zone.

Assignments (9)