US 7,374,590 B2
Reducing sulfur dioxide emissions from coal combustion
Robert R. Holcomb, Nashville, Tenn. (US)
Assigned to Demeter Systems LLC, Orlando, Fla. (US)
Appl. No. 10/473,871
PCT Filed Mar. 28, 2002, PCT No. PCT/US02/10151
§ 371(c)(1), (2), (4) Date Apr. 06, 2004,
PCT Pub. No. WO02/079356, PCT Pub. Date Oct. 10, 2002.
Claims priority of provisional application 60/279325, filed on Mar. 28, 2001.
Prior Publication US 2004/0154220 A1, Aug. 12, 2004
Int. Cl. C10L 5/00 (2006.01)
U.S. Cl. 44—620  [44/622; 44/624] 17 Claims
OG exemplary drawing
 
1. A process for treating high sulfur coal, which comprises at least 0.5 percent by weight sulfur, to reduce sulfur dioxide emissions when the coal is burned, which method comprises:
(a) placing the coal in an environment of reduced pressure sufficient to fracture a portion of the coal by withdrawing ambient fluids trapped within the coal,
(b) contacting the fractured coal with an aqueous silica colloid composition supersaturated with calcium carbonate,
(c) removing the majority of the aqueous composition from contact with the coal, and
(d) pressurizing the aqueous composition-treated coal under a carbon dioxide atmosphere for a period of time sufficient for the calcium carbonate to enter fractures in the coal produced in step (a).