Sorbent comprising carbon and nitrogen and methods of using the same

• US 10,130,930 B2
• Filed: 03/03/2017
• Issued: 11/20/2018
• Est. Priority Date: 03/06/2013
• Status: Active Grant

• Current Assignee: Midwest Energy Emissions Corp.
• Original Assignee: Midwest Energy Emissions Corp.
• Inventors: Olson, Edwin S., Pavlish, John Henry
• Primary Examiner(s): Rump, Richard M
• Application Number:
  US15/449,112
• Publication Number:
  US 20170173557A1
• Time in Patent Office: 627 Days
• CPC Class Codes: B01D 2253/102 Carbon
• CPC Class Codes: B01D 2253/202 Polymeric adsorbents
• CPC Class Codes: B01D 2253/25 Coated, impregnated or composite adsorbents
• CPC Class Codes: B01D 2253/304 Linear dimensions, e.g. particle shape, diameter
• CPC Class Codes: B01D 2257/60 Heavy metals or heavy metal compounds
• CPC Class Codes: B01D 2257/602 Mercury or mercury compounds
• CPC Class Codes: B01D 2258/0283 Flue gases
• CPC Class Codes: B01D 53/02 by adsorption, e.g. preparative gas chromatography solid sorbent compositions B01J20/00, preparation of inorganic compounds or elements C01
• CPC Class Codes: B01D 53/025 with wetted adsorbents; Chromatography analytical chromatography G01N30/00 - G01N30/96; for liquids B01D15/08
• CPC Class Codes: B01D 53/04 with stationary adsorbents B01D53/025 takes precedence
• CPC Class Codes: B01D 53/10 with dispersed adsorbents
• CPC Class Codes: B01D 53/64 Heavy metals or compounds thereof, e.g. mercury
• CPC Class Codes: B01D 53/81 Solid phase processes
• CPC Class Codes: B01D 53/8665 Removing heavy metals or compounds thereof, e.g. mercury
• CPC Class Codes: B01J 20/20 comprising free carbon; comprising carbon obtained by carbonising processes
• CPC Class Codes: B01J 20/205 Carbon nanostructures, e.g. nanotubes, nanohorns, nanocones, nanoballs carbon nanotubes per se C01B32/15
• CPC Class Codes: B01J 20/22 comprising organic material
• CPC Class Codes: B01J 20/28004 Sorbent size or size distribution, e.g. particle size
• CPC Class Codes: B01J 20/3085 Chemical treatments not covered by groups B01J20/3007 - B01J20/3078
• CPC Class Codes: B01J 20/3204 Inorganic carriers, supports or substrates
• CPC Class Codes: B01J 20/3208 : Polymeric carriers, supports or substrates
• CPC Class Codes: B01J 20/3236 : containing metal, other than zeolites, e.g. oxides, hydroxides, sulphides or salts
• CPC Class Codes: B01J 20/324 : containing free carbon, e.g. activated carbon
• CPC Class Codes: B01J 20/3293 : Coatings on a core, the core being particle or fiber shaped, e.g. encapsulated particles, coated fibers
• CPC Class Codes: C01B 32/336 : characterised by gaseous activating agents
• CPC Class Codes: C01B 32/342 : characterised by non-gaseous activating agents
• CPC Class Codes: C01B 32/36 : Reactivation or regeneration

Abstract

The present invention relates to sorbents including carbon and nitrogen. In various embodiments, the sorbent can remove mercury from a mercury-containing gas that includes sulfur (VI) such as SO₃ more efficiently than other sorbents. The sorbent can include a graphene edge comprising an active site for mercury oxidation and a nitrogen layer structure including cationic nitrogen atoms, neutral nitrogen atoms, or a combination thereof proximate the active site.

Claims

1. A method of reducing the mercury content in a mercury-containing gas, the method comprising:

contacting a mercury-containing gas with a sorbent comprising a carbon layer structure, the carbon layer structure comprising nitrogen and about 50 wt % to about 99 wt % carbon, the carbon layer structure at least partially covered by a nitrogen layer structure, to form a mercury-sorbent composite composition, wherein the nitrogen layer structure is porous to mercury of the mercury-containing gas and reactive to acid gases of the mercury-containing gas; and

separating at least some of the mercury-sorbent composition from the mercury-containing gas, to give a separated gas, wherein the concentration of nitrogen in the nitrogen layer structure is higher than the concentration of nitrogen in carbon layer structure of the sorbent.

2. The method of claim 1, wherein the carbon is activated carbon.

3. The method of claim 1, wherein the nitrogen layer structure of the sorbent comprises a layer at the surface of the sorbent having a thickness of about 0.001% to about 49% of the largest dimension of the sorbent.

4. The method of claim 1, wherein the nitrogen layer structure comprises cationic nitrogen atoms, neutral nitrogen atoms, or a combination thereof.

5. The method of claim 1, wherein the sorbent comprises a graphene edge on the carbon layer structure comprising an active site for mercury oxidation, the active site proximate the nitrogen layer structure.

6. The method of claim 1, wherein an active site of the sorbent comprises a promoted carbon that has reacted with a promoter, wherein the promoter is added as a solid, liquid, or gas to the mercury containing gas, to the fuel or combustion zone that provides the mercury the containing gas, or a combination thereof.

7. The method of claim 6, wherein the promoter comprises HCl, HBr, HI, Br₂, Cl₂, I₂, BrCl, IBr, ICl, ClF, PBr₃, PCl₅, SCl₂, CuCl₂, CuBr₂, Al₂Br₆, FeI_x, FeBr_y, FeCl_z, MnBr₂, MnCl₂, NiBr₂, NiCl₂, NiI₂, ZnBr₂, ZnCl₂, ZnI₂, NH₄Br, NH₄Cl, NH₄I, NH₄F, (NH₄)₂SO₄, H₂SO₄, NH₄SO₄H, (NH₄)₂S₂O₃, FeNH₄(SO₄)₂, Fe(NH₄)₂(SO₄)₂, FeNH₄Br₄, FeNH₄Cl₄, AlNH₄(SO₄)₂, F₂, F⁻

, Br⁻

, I⁻

, NH₄Br, NaBr, CaBr₂, NaCl, CaCl₂, NH₄Cl, NH₄I, NaI, CaI₂, KI, KCl, HI, NH₄F, NaF, CaF₂, HF, LiBr, AgCl, AgBr, CHI₃, CH₃Br, AuBr, MgBr₂, MgCl₂, hydrates thereof, or combinations thereof wherein x, y, and z are independently 1, 2, 3, or 4.

8. The method of claim 4, wherein the nitrogen layer structure is formed in the mercury-containing gas.

9. The method of claim 4, wherein the nitrogen layer structure is formed on the sorbent prior to injecting the sorbent into the mercury-containing gas.

10. The method of claim 4, wherein forming the nitrogen layer structure comprises depositing a layer of preformed organonitrogen polymer on the carbon and heating the layer to form the nitrogen layer structure.

11. The method of claim 4, wherein the nitrogen layer structure is formed by a method comprising:

contacting the carbon with an ammonium salt, ammonium precursor, or ammonium compound to form the nitrogen layer structure.

12. The method of claim 11, wherein the ammonium salt, ammonium precursor, or ammonium compound is an ammonium halide, a methylammonium halide, an ammonium salt of an oxyacid of a Group VI element, an ammonium salt of an oxyacid of a Group V element, or a combination thereof.

13. The method of claim 11, wherein the ammonium salt, ammonium precursor, or ammonium compound is ammonium bromide, ammonium iodide, ammonium chloride, an organic halide with a formula of CH₃NH₃X (wherein X is Cl, Br or I), ammonium sulfate, ammonium hydrogen sulfate, ammonium sulfite, ammonium hydrogen sulfite, ammonium persulfate, ammonium pyrosulfate, ammonium thiosulphate, ammonium dithionite, ammonium aluminium sulfate, ammonium iron sulfate, ammonium sulfamate, ammonium phosphate, diammonium phosphate, ammonium hydrogen phosphate, ammonium dihydrogen phosphate, ammonium thiophosate, ammonium nitrate, ammonium nitrite, ammonium carbonate, ammonium thiocyanate, ammonium sulfide, ammonium hydrogen sulfide, ammonium acetate, ammonium carbamate, ammonium carbonate, ammonium chlorate, ammonium chromate, ammonium fluoride, ammonium formate, ammonium hydroxide, ammonium perchlorate, sodium nitrite, sodium nitrate, lithium nitrite, lithium nitrate, barium nitrite, barium nitrate, cerium nitrite, cerium nitrate, FeNH₄(SO₄)₂, Fe(NH₄)₂(SO₄)₂, FeNH₄Br₄, FeNH₄Cl₄, AlNH₄(SO₄)₂, hydrates thereof, or a combination thereof.

14. The method of claim 11, wherein forming the nitrogen layer structure comprises injecting the ammonium salt, ammonium precursor, or ammonium compound and the carbon in a flue gas in the same location or at different locations wherein:

the ammonium salt, ammonium precursor, or ammonium compound is contacted with the carbon to form the sorbent within the flue gas,

the ammonium salt, ammonium precursor, or ammonium compound decomposes or vaporizes and then contacts the carbon to form the sorbent,

the ammonium salt, ammonium precursor, or ammonium compound contacts the carbon to form the sorbent, or

a combination thereof.

15. The method of claim 1, wherein the nitrogen in the surface layer 1) decreases neutralization of carbocations in the carbon by at least one of SO₃ and H₂SO₄, as compared to a corresponding sorbent comprising less or substantially no nitrogen, 2) at least partially blocks carbocations in the carbon from at least one of SO₃ and H₂SO₄, as compared to a corresponding sorbent comprising less or substantially no nitrogen, or 3) a combination thereof.

16. The method of claim 1, further comprising:

promoting at least a portion of an unpromoted sorbent by contacting the portion of the unpromoted sorbent with a promoter to form the sorbent.

17. The method of claim 1, wherein the separating at least some of the mercury-sorbent composition from the mercury containing gas comprises separating in a particulate separator.

18. A method of making a sorbent, comprising:

promoting at least a portion of an unpromoted sorbent comprising carbon and nitrogen comprising contacting the portion with a promoter to form a promoted sorbent comprising a carbon layer structure, the carbon layer structure comprising about 50 wt % to about 99 wt % carbon, and the carbon layer structure is covered by a nitrogen layer structure, wherein the sorbent comprises a graphene edge on the carbon comprising an active site for mercury oxidation and a nitrogen layer structure comprising cationic nitrogen atoms, neutral nitrogen atoms, or a combination thereof proximate the active site, wherein the concentration of nitrogen in a surface layer of the sorbent is higher than the concentration of nitrogen in a core of the sorbent comprising nitrogen and the nitrogen layer structure is porous to mercury of the mercury-containing gas and reactive to acid gases of the mercury-containing gas.

19. A sorbent, comprising:

a promoted carbon layer structure comprising about 50 wt % to about 99 wt % carbon, further comprising nitrogen in a nitrogen layer structure coated thereon and comprising a graphene edge on the carbon comprising an active site for mercury oxidation and the nitrogen layer structure comprising cationic nitrogen atoms, neutral nitrogen atoms, or a combination thereof proximate the active site, wherein the nitrogen layer structure is porous to mercury, and a concentration of the nitrogen in the nitrogen layer is greater than a concentration of nitrogen in the promoted carbon layer structure comprising nitrogen.