Sorbents for coal combustion

• US 9,945,557 B2
• Filed: 06/27/2017
• Issued: 04/17/2018
• 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:
  US15/634,331
• Publication Number:
  US 20170292700A1
• Time in Patent Office: 294 Days
• 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 iodine are added to coal to mitigate the release of mercury and/or other harmful elements into the environment during combustion of coal containing natural levels of mercury.

Claims

1. A method for burning coal in a furnace to reduce emissions of mercury from a coal burning facility, the method comprising:

adding a mercury sorbent composition onto the coal upstream of the furnace, into the flue gases in a plant section of the facility downstream of the furnace, or in a combination of upstream and downstream additions;

adding a sulfur sorbent composition onto the coal upstream of the furnace, into the flue gases in a plant section of the facility downstream of the furnace, or in a combination of upstream and downstream additions;

combusting the coal in the furnace;

measuring the level of mercury present in the flue downstream from the addition of sorbent compositions; and

if the measured mercury level is above a target level, increasing a rate of addition of the mercury sorbent composition;

or

if the measured mercury level is below a target level, decreasing a rate of addition of at least one of the components or leaving the rate of addition unchanged, wherein the mercury sorbent composition comprises a halogen compound and the sulfur sorbent composition comprises silica and alumina.

2. The method of claim 1, wherein the sulfur sorbent composition comprises more than 2% by weight silica and greater than 2% by weight alumina.

3. The method of claim 1, wherein the sulfur sorbent composition comprises an aluminosilicate clay.

4. The method of claim 3, wherein the aluminosilicate clay is montmorillonite or kaolin.

5. The method of claim 1 comprising adding the sulfur sorbent downstream of the furnace in a region having a temperature of 1500-2700°

F.

6. The method of claim 1 comprising adding the mercury sorbent downstream of the furnace in a region having a temperature of 1500-2700°

F.

7. The method of claim 1 wherein the mercury sorbent composition comprises an iodine compound.

8. The method of claim 6 wherein the mercury sorbent composition comprises an iodine compound.

9. The method of claim 1, wherein emissions of mercury are reduced by at least 70%, compared to burning the coal without applied sorbent compositions.

10. The method of claim 1, wherein both the mercury sorbent composition and the sulfur sorbent composition are added upstream of the furnace.

11. The method of claim 1, wherein both the mercury sorbent composition and the sulfur sorbent composition are added downstream of the furnace where the temperature is 1500-2700°

F.