Reducing sulfur dioxide emissions from coal combustion
AssigneeDemeter Systems LLC
InventorRobert R. Holcomb
Life of this patent
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Abstract
A process of treating high sulfur coal to reduce sulfur dioxide emission when the high sulfur coal is burned comprising placing coal in pressure tank (16) of reduced pressure sufficient to fracture a portion of the coal by withdrawing ambient fluids trapped within the coal. The fractured coal is contacted with an aqueous silica colloid composition supersaturated with calcium carbonate via conduit (21), and the majority of the aqueous composition is then removed from contact with the coal. The aqueous composition-treated coal is pressurized in pressure tank (16) under a carbon dioxide atmosphere for a period of time sufficient for the calcium carbonate to enter fractures in the coal produced in the first step.
Claims17
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).
A high sulfur coal, wherein the coal is vacuum fractured, comprises at least about 0.5 percent by weight sulfur, and further comprises calcium carbonate deposited within fractures in the coal in an amount sufficient to provide a Ca:S molar ratio of at least 0.5.
A process for producing energy from burning high sulfur coal of at least 0.5 percent by weight sulfur while reducing the sulfur dioxide content of the emission from such burning, which process comprises depositing calcium carbonate within fractures in vacuum-fractured coal and burning the resulting calcium carbonate-containing high sulfur coal at a high temperature of about 2400-2600° Fahrenheit or about 3200-3700° Fahrenheit, wherein the calcium carbonate is deposited within the fractures of the coal in accordance with the process of
- (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).
Dependencies are inferred from the claim text.