Reducing mercury emissions from the burning of coal

• US 10,359,192 B2
• Filed: 10/24/2017
• Issued: 07/23/2019
• 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:
  US15/792,087
• Publication Number:
  US 20180045408A1
• Time in Patent Office: 637 Days
• 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 of combusting coal to reduce the amount of mercury released into the environment from a coal burning facility, comprising

combusting the coal to produce heat energy, fly ash, and flue gas;

injecting a mercury sorbent comprising halogen into the flue gas where the temperature is higher than 500°

C.; and

adding a powder sorbent to the coal before combustion or injecting a powder sorbent into the furnace while the coal is combusting,

wherein the powder sorbent comprises a source of calcium, alumina, and silica.

2. The method according to claim 1, comprising injecting the mercury sorbent where the temperature is higher than 1000°

C.

3. The method according to claim 1, comprising injecting the mercury sorbent where the temperature is 1500-2200°

F.

4. The method according to claim 1, comprising injecting the mercury sorbent where the temperature is 2400-2600°

F.

5. The method according to claim 1, comprising injecting the mercury sorbent where the temperature is 3000-3300°

F.

6. The method according to claim 1, wherein the mercury sorbent comprises a bromine compound.

7. The method according to claim 1, wherein the mercury sorbent comprises an iodine compound.

8. The method according to claim 1, wherein the powder sorbent comprises an aluminosilicate material.

9. The method according to claim 1, wherein the powder sorbent comprises cement kiln dust.

10. The method according to claim 1, comprising adding the powder sorbent to the coal before combustion.

11. The method according to claim 1, wherein the powder sorbent comprises oxides of silicon, aluminum, magnesium, iron, sodium, and potassium.

12. The method according to claim 10, wherein the mercury sorbent comprises a bromine compound.

13. The method according to claim 12, wherein the mercury sorbent comprises a bromide compound.

14. The method according to claim 1 wherein the mercury sorbent comprises an alkaline earth bromide compound.

15. The method according to claim 10, wherein the mercury sorbent comprises an iodine compound.

16. The method according to claim 15, wherein the mercury sorbent comprises an iodide compound.