Reducing mercury emissions from the burning of coal

• US 9,416,967 B2
• Filed: 12/09/2014
• Issued: 08/16/2016
• 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
• Application Number:
  US14/564,277
• Publication Number:
  US 20150096480A1
• Time in Patent Office: 616 Days
• US Class Current: 1/1
• CPC Class Codes: B01D 53/508 by treating the gases with solids
• CPC Class Codes: B01D 53/64 Heavy metals or compounds thereof, e.g. mercury
• CPC Class Codes: C04B 18/065 Residues from coal gasification
• CPC Class Codes: C04B 18/162 Cement kiln dust; Lime kiln dust
• CPC Class Codes: C04B 20/023 Chemical treatment
• CPC Class Codes: C04B 2103/0088 Compounds chosen for their latent hydraulic characteristics, e.g. pozzuolanes
• CPC Class Codes: C04B 28/04 Portland cements
• CPC Class Codes: C04B 40/0039 Premixtures of ingredients
• CPC Class Codes: C04B 40/0608 Dry ready-made mixtures, e.g. mortars at which only water or a water solution has to be added before use
• 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 15/003 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: Y02E 20/32 Direct CO2 mitigation
• CPC Class Codes: Y02W 30/91 Use of waste materials as fillers for mortars or concrete
• CPC Class Codes: Y10S 423/05 Automatic, including computer, control

Abstract

Sorbent components containing halogen, calcium, alumina, and silica are used in combination during coal combustion to produce environmental benefits. Sorbents such as calcium bromide are added to the coal ahead of combustion and other components are added into the flame or downstream of the flame, preferably at minimum temperatures to assure complete formation of the refractory structures that result in various advantages of the methods. When used together, the components

• • reduce emissions of elemental and oxidized mercury;
  • increase the level of Hg, As, Pb, and/or Cl in the coal ash;
  • decrease the levels of leachable heavy metals (such as Hg) in the ash, preferably to levels below the detectable limits; and
  • make a highly cementitious ash product.

Claims

1. A method for burning coal to reduce the amount of mercury released into the atmosphere, comprising:

applying sorbent components comprising a halogen compound and an aluminosilicate material onto coal; and

delivering the coal with the sorbent components applied into a coal burning furnace; and

burning the coal with applied sorbent components in the furnace to produce heat energy, flue gas, and coal ash.

2. The method according to claim 1, wherein the coal is sub-bituminous coal.

3. The method according to claim 1, wherein the coal is bituminous coal.

4. The method according to claim 1, wherein the halogen compound is a bromine compound.

5. The method according to claim 4, wherein the bromine compound comprises calcium bromide.

6. The method according to claim 1, wherein the aluminosilicate material is a clay.

7. The method according to claim 6, wherein the aluminosilicate material comprises kaolinite, calcium montmorillonite, or sodium montmorillonite.

8. The method according to claim 1, wherein the aluminosilicate material comprises kaolin.

9. The method according to claim 1, wherein the aluminosilicate material comprises meta-kaolin.

10. The method according to claim 1, wherein the aluminosilicate material comprises a zeolite.

11. The method according to claim 1, wherein the aluminosilicate material comprises a feldspar.

12. The method according to claim 7, wherein the halogen compound comprises calcium bromide.

13. The method according to claim 1, wherein the sorbent components further comprise an alkaline powder comprising calcium.

14. The method according to claim 13, wherein the alkaline powder is selected from cement kiln dust and portland cement.

15. The method according to claim 1, further comprising measuring the acid leaching of mercury from the ash, and increasing the amount of aluminosilicate applied to the coal if the measured value of leaching is above a target value.

16. The method according to claim 1, further comprising measuring a level of mercury in the flue gas, and increasing the amount of halogen compound applied to the coal if the measured level is above a target level.