Methods of operating a coal burning facility

• US 20070168213A1
• Filed: 01/11/2007
• Published: 07/19/2007
• Est. Priority Date: 01/18/2006
• 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.
• Granted Patent: US 8,150,776 B2
• Time in Patent Office: Days
• US Class Current: 705/30
• CPC Class Codes: B01D 2253/104 Alumina
• CPC Class Codes: B01D 2253/106 Silica or silicates
• CPC Class Codes: B01D 2257/602 Mercury or mercury compounds
• CPC Class Codes: B01D 53/83 with moving reactants
• CPC Class Codes: F23J 15/003 for supplying chemicals to fumes, e.g. using injection devices
• CPC Class Codes: F23J 2215/60 Heavy metals; Compounds thereof
• 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: G06Q 10/30 Administration of product recycling or disposal
• CPC Class Codes: G06Q 40/12 Accounting
• CPC Class Codes: Y02P 90/90 Financial instruments for climate change mitigation, e.g. environmental taxes, subsidies or financing
• CPC Class Codes: Y02W 90/00 Enabling technologies or technologies with a potential or indirect contribution to greenhouse gas [GHG] emissions mitigation
• CPC Class Codes: Y10T 436/12 Condition responsive control

Abstract

Methods involve adding sorbent components, such as calcium oxide, alumina, and silica, as well as optional halogens as part of environmental control. Use of the sorbents leads to significant reductions in sulfur and mercury emissions that otherwise would result from burning coal. Use of the sorbents leads to production of waste coal ash that, while higher in mercury, is nevertheless usable as a commercial product because the mercury in the ash is non-leaching and because the coal ash has a higher cementitious nature by virtue of the increased content of the sorbent components in the ash. Thus, the methods involve adding powders having qualities that lead to the production of a cementitious coal ash while at the same time reducing emissions from a coal burning facility.

Claims

1. A method of increasing the value of coal burned in a coal burning facility, the method comprising:

combusting coal containing mercury in a presence of at least one sorbent to produce heat energy, ash, and flue gases, said ash containing at least 90% by weight of said mercury originally present in said coal, said ash having an amount of acid leachable mercury that is less than a level of acid leachable mercury in an ash produced by combusting coal without said at least one sorbent;

monitoring said flue gases for said mercury and adjusting said presence of said at least one sorbent to achieve a desired mercury emission to comply with an environmental regulation; and

realizing a monetary savings by an avoidance of disposal costs of said fly ash produced.

2. The method according to claim 1 further comprising reflecting said monetary savings on one or more financial statements.

3. The method according to claim 2, wherein said financial statements are at least one of a tax return, a balance sheet, a cash flow analysis, a shareholder equity statement, and an income statement.

4. The method according to claim 1 further comprising calculating a net savings per unit of coal burned.

5. The method according to claim 4 further comprising offsetting a cost of at least one of said coal and said at least one sorbent with a said net savings per unit of coal burned.

6. The method according to claim 1, wherein said monetary savings from said presence of said at least one sorbent increases the value of said coal that is combusted by at least 50%.

7. The method according to claim 1, wherein said monetary savings from said presence of said at least one sorbent is greater than a cost of said presence of said at least one sorbent.

8. The method according to claim 1, wherein said at least one sorbent comprises at least one of CaO, SiO₂, Al₂O₃, Fe₂O₃, Na₂O, and K₂O.

9. The method according to claim 1, wherein said coal burning facility is an electric utility plant.

10. The method according to claim 1, wherein said coal burning facility is a cement plant.

11. The method according to claim 1 further comprising creating mercury emissions trading credits.

12. A method of operating a coal burning facility comprising:

combusting coal in a furnace and in the presence of a sorbent composition; and

generating energy by the combusting coal;

wherein said sorbent composition is at least one of added onto said coal prior to said combusting, applied into said furnace during said combusting and applied into flue gases downstream of said furnace,

wherein said presence of said sorbent composition reduces emissions of at least one of mercury and sulfur compared to combusting coal without said sorbent composition, and

wherein said presence of said sorbent composition produces a coal ash more cementitious in nature compared to a coal ash produced from combusting coal without said presence of said sorbent composition.

13. The method according to claim 12 further comprising selling said energy.

14. The method according to claim 13, wherein said energy is electricity.

15. The method according to claim 12, wherein said combusting coal in said presence of said sorbent composition increases a power generation per unit of coal burned as compared to combusting coal without said presence of said sorbent composition.

16. The method according to claim 12, wherein said sorbent composition comprises at least one of CaO, SiO₂, Al₂O₃, Fe₂O₃, Na₂O, and K₂O.

17. The method according to claim 12 further comprising using said energy in the production of cement.

18. A method of making a business decision to choose among various ways of complying with environmental regulations regarding a release of mercury, the method comprising:

providing a first system that calls for a use of at least one sorbent added onto coal or into a coal burning facility during combustion, wherein said use of said at least one sorbent reduces at least one of mercury emission and sulfur emission, and producing an ash with an increased level of mercury, said ash having an environmentally acceptable level of an acid leachable mercury;

providing a second system that involves a capital investment in at least one device to remove mercury from an emission from said coal burning facility;

carrying out at least one of calculating a return on investment for both said first system and said second system, preparing a balance sheet for comparing both said first system and said second system, and preparing an income statement comparing both said first system and said second system; and

making a business decision between implementing said first system and implementing said second system based on at least one of a calculated return on investment, a balance sheet, and an income statement.

19. The method according to claim 18, wherein said at least one sorbent comprises at least one of CaO, SiO₂, Al₂O₃, Fe₂O₃, Na₂O, and K₂O.

20. The method according to claim 18, wherein said coal burning facility is an electric utility plant.

21. The method according to claim 18, wherein said coal burning facility is a cement plant.

22. The method according to claim 18 further comprising meeting a regulation requirement for at least one of said mercury emission and sulfur emission.

23. A method of operating a coal plant to produce energy and waste ash, the method comprising:

burning coal in the presence of a sorbent composition to produce a waste ash with a reduced level of acid leachable mercury when compared to a waste ash produced from burning coal without said sorbent composition; and

recovering said waste ash with a reduced mercury emission and mixing it with cementitious powder to make a cement product;

wherein said waste ash with a reduced level of acid leachable mercury has a reduction in mercury leaching from said waste ash as compared to a waste ash produced from burning coal without said sorbent composition.

24. The method according to claim 23 further comprising selling said cement product into a commercial market.

25. The method according to claim 23, wherein said cementitious powder is at least one of a Portland cement, a pozzolan material, a slag, and a cement kiln dust.

26. The method according to claim 23 further comprising creating mercury emissions trading credits.

27. The method according to claim 23, wherein said sorbent composition comprises at least one of CaO, SiO₂, Al₂O₃, Fe₂O₃, Na₂O, and K₂O.

28. A method of operating a coal burning plant to produce heat energy and waste ash, the method comprising:

burning coal in the presence of at least one sorbent that increases an amount of a heavy metal in a fly ash and that decreases an amount of an acid leachable heavy metal in said fly ash when compared to said burning coal without said at least one sorbent; and

selling said fly ash as an industrial raw material.

29. The method according to claim 28 further comprising producing electricity.

30. The method according to claim 29 further comprising selling said electricity.

31. The method according to claim 29 further comprising using said energy in producing cement.

32. The method according to claim 31 further comprising selling said cement.

33. The method according to claim 28, wherein said at least one sorbent comprises at least one of CaO, SiO₂, Al₂O₃, Fe₂O₃, Na₂O, and K₂O.