Sorbents for coal combustion

• US 8,545,778 B2
• Filed: 11/16/2012
• Issued: 10/01/2013
• 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:
  US13/679,775
• Publication Number:
  US 20130074745A1
• Time in Patent Office: 319 Days
• Field of Search: 431/2, 423/210, 423/242.1, 423/244.01, 423/244.07, 423/DIG.5, 445/05, 446/03, 446/04, 446/20, 446/21, 446/22, 446/24, 422/105, 422/108, 422/111
• 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 for reducing emissions of mercury and sulfur arising from combustion of coal in the furnace of a coal burning system, comprising adding a sulfur sorbent composition and a mercury sorbent composition into the coal burning system, wherein the mercury sorbent composition comprises a bromine compound, and the sulfur sorbent composition comprises cement kiln dust.

2. A method according to claim 1, wherein the mercury sorbent composition comprises calcium bromide.

3. A method according to claim 1, wherein the sulfur sorbent composition comprises greater than 2% by weight silica and greater than 2% by weight alumina.

4. A method according to claim 1, wherein the sulfur sorbent composition further comprises an aluminosilicate clay.

5. A method according to claim 1, wherein 90% or more of the mercury in the coal is captured in the ash product produced from combustion.

6. A method according to claim 1, comprising adding the mercury sorbent onto the coal before combustion in the furnace.

7. A method according to claim 1, wherein the sorbent compositions are added separately into the coal burning system.