Sorbents for coal combustion

• US 8,703,081 B2
• Filed: 09/25/2013
• Issued: 04/22/2014
• Est. Priority Date: 03/17/2005
• Status: Active Grant

• Current Assignee: Nox Ii Ltd. (Arthur J Gallagher & Company)
• Original Assignee: Nox Ii Ltd. (Arthur J Gallagher & Company)
• Inventors: Comrie, Douglas C.
• Primary Examiner(s): VANOY, TIMOTHY C
• Application Number:
  US14/036,036
• Publication Number:
  US 20140020608A1
• Time in Patent Office: 209 Days
• Field of Search: 423/210, 423/242.1, 423/244.01, 423/244.07, 423/DIG.5, 431/2, 445/05, 446/03, 446/04, 446/20, 446/21, 446/22, 446/24
• US Class Current: 423/210
• CPC Class Codes: B01D 2253/104 Alumina
• CPC Class Codes: B01D 2253/11 Clays
• CPC Class Codes: B01D 2257/30 Sulfur compounds
• CPC Class Codes: B01D 2257/602 Mercury or mercury compounds
• CPC Class Codes: B01D 53/04 with stationary adsorbents B01D53/025 takes precedence
• CPC Class Codes: B01D 53/30 Controlling by gas-analysis apparatus regulating non electrical variables in general G05D
• CPC Class Codes: B01D 53/485 containing only one sulfur compound other than sulfur oxides or hydrogen sulfide
• CPC Class Codes: B01D 53/64 Heavy metals or compounds thereof, e.g. mercury
• CPC Class Codes: B01D 53/78 with gas-liquid contact
• CPC Class Codes: B01J 20/041 Oxides or hydroxides
• CPC Class Codes: B01J 20/043 Carbonates or bicarbonates, e.g. limestone, dolomite, aragonite
• CPC Class Codes: B01J 20/046 containing halogens, e.g. halides
• CPC Class Codes: B01J 20/06 comprising oxides or hydroxides of metals not provided for in group B01J20/04
• CPC Class Codes: B01J 20/12 Naturally occurring clays or bleaching earth
• CPC Class Codes: B01J 20/16 Alumino-silicates B01J20/12 takes precedence
• CPC Class Codes: B01J 2220/42 Materials comprising a mixture of inorganic materials materials coated or impregnated on a carrier B01J20/32
• CPC Class Codes: C10L 10/00 Use of additives to fuels or fires for particular purposes additives for liquid carbonaceous fuels characterised by their chemical nature C10L1/10; using binders for briquetting solid fuels C10L5/10; using additives to improve the combustion of solid fuels C10L9/10
• CPC Class Codes: C10L 10/02 for reducing smoke development
• CPC Class Codes: C10L 9/10 by using additives
• CPC Class Codes: F23J 15/00 Arrangements of devices for treating smoke or fumes
• CPC Class Codes: F23J 15/025 : using filters
• CPC Class Codes: F23J 15/04 : using washing fluids scrubbers for removing solids only F23J15/022
• CPC Class Codes: F23J 7/00 : Arrangement of devices for supplying chemicals to fire
• CPC Class Codes: F23K 1/00 : Preparation of lump or pulverulent fuel in readiness for delivery to combustion apparatus
• CPC Class Codes: F23K 2201/505 : with additives
• CPC Class Codes: Y02P 40/10 : Production of cement, e.g. improving or optimising the production methods; Cement grinding
• CPC Class Codes: Y10S 423/05 : Automatic, including computer, control

Abstract

Sorbent compositions containing halogen and calcium are added to coal to mitigate the release of sulfur and/or other harmful elements, including mercury, into the environment during combustion of coal containing natural levels of mercury.

Claims

1. A method of reducing mercury emissions that arise from combustion of coal in the furnace of a coal burning facility, the method comprising applying a mercury sorbent onto the coal upstream of the furnace, or into the convective pathway of the furnace where the temperature is 1500°

F. to 2700°

F. and measuring the level of mercury escaping from the coal burning facility, wherein the mercury sorbent comprises sodium iodide.

2. The method according to claim 1, comprising adding sodium iodide onto coal upstream of the furnace.

3. The method according to claim 1, wherein the mercury sorbent comprises an aqueous solution of sodium iodide.

4. The method according to claim 1, further comprising applying a sulfur sorbent onto the coal upstream of the furnace, or into the convective pathway of the furnace where the temperature is 1500°

F. to 2700°

F., wherein the sulfur sorbent comprises calcium.

5. The method according to claim 4, wherein the sulfur sorbent comprises cement kiln dust, portland cement, or lime kiln dust.

6. The method according to claim 4, wherein the sulfur sorbent comprises cement kiln dust.

7. The method according to claim 4, wherein the sulfur sorbent further comprises at least 2% by weight silica and at least 2% by weight alumina.

8. The method according to claim 7, wherein the sulfur sorbent comprises an aluminosilicate clay.

9. The method according to claim 7, wherein the iodide salt is sodium iodide.

10. A method for reducing the level of harmful emissions released into the environment from a coal burning facility, the method comprising adding sorbent components onto coal upstream of the furnace, delivering the coal with the applied sorbents into the furnace, and combusting the coal in the furnace, wherein the sorbent components comprise an iodide salt and cement kiln dust.

11. The method according to claim 10, wherein combusting produces combustion gases and ash, the method further comprising:

removing the ash from the combustion gases by capturing it in a particulate removal system disposed in a convective pathway of the facility downstream of the furnace;

measuring the level of mercury and/or sulfur remaining in the combustion gases after capture of the ash; and

adjusting the rate of addition of the sulfur sorbent composition or of the mercury sorbent composition according to the measured level of mercury and/or sulfur.

13. The method according to claim 11, wherein the sulfur sorbent composition comprises Portland cement, cement kiln dust, or lime kiln dust.

14. The method according to claim 11, further comprising:

measuring the level of mercury and/or sulfur remaining in the combustion gases after capture of the ash; and

adjusting the rate of addition of the sulfur sorbent composition or of the mercury sorbent composition according to the measured level of mercury and/or sulfur.

15. The method according to claim 11, wherein the mercury sorbent composition comprises sodium iodide.

16. The method according to claim 14, wherein the sulfur sorbent composition comprises cement kiln dust.

17. The method according to claim 11, wherein the sulfur sorbent composition comprises an aluminosilicate clay.

12. A method for reducing emissions of mercury arising from combustion of mercury containing fuels in a fuel burning facility, the method comprising:

applying a mercury sorbent and a sulfur sorbent composition onto the fuel;

delivering the fuel with the sorbent compositions applied into a furnace of the facility;

combusting the fuel with the sorbent compositions in the furnace to produce combustion gases and ash;

removing the ash from the combustion gases by capturing it in a particulate removal system disposed in a convective pathway of the facility downstream of the furnace;

wherein the mercury sorbent composition comprises an iodine compound and the sulfur sorbent composition comprises calcium, silica, and alumina.