Low sulfur coal additive for improved furnace operation
AssigneeOil Sands Underground Mining, Inc.
InventorsStephen Allen Johnson, John Wurster, John Philip Comer
Life of this patent
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Abstract
The present invention is directed to additives for coal-fired furnaces, particularly furnaces using a layer of slag to capture coal particles for combustion. The additive(s) include iron, mineralizer(s), handling aid(s), flow aid(s), and/or abrasive material(s). The iron and mineralizers can lower the melting temperature of ash in low-iron, high alkali coals, leading to improved furnace performance.
Claims36
A method of operating a solid fuel fired boiler, comprising:
- introducing a solid fuel into the boiler;
- introducing an iron-bearing material into the boiler;
- introducing at least one carbon compound along with the iron-bearing material, the at least one carbon compound promoting reduction of iron oxides;
- and at least one of the following steps are performed:
- (i) at least partially combusting the solid fuel to produce an ash slag, wherein at least one ash fusion temperature characteristic selected from the group consisting of initial deformation temperature, softening temperature, hemispherical temperature, and fluid temperature is less than the same ash fusion temperature characteristic of a second ash slag produced from combustion of the solid fuel alone;
- and
- (ii) at least partially combusting the solid fuel to produce an ash slag, wherein at least a portion of the iron bearing material fluxes the ash slag to produce a composite ash slag having a melting point less than the melting point of ash slag produced from the combustion of the solid fuel alone.
The method of claim 6, wherein the composite ash slag has a viscosity such that the composite ash slag flows from the boiler, and wherein the iron bearing material is at least one of mill scale from steel production and dust from blast furnace gas cleaning equipment.
A method of operating a solid fuel fired boiler, comprising:
- introducing a solid fuel into at least one of a slag-type furnace and a wet-bottom boiler, wherein the at least one of the slag-type furnace and the wet-bottom boiler comprises:
- a fuel storage bunker,
- a burner,
- fuel transfer system communicating with the fuel storage bunker and the burner, and
- a combustion chamber comprising an enclosure at least partially surrounding the burner,
- introducing an iron-bearing material into at least one of the fuel storage bunker, the fuel transfer system, the burner, and the combustion chamber, and at least one of the following:
- (i) at least partially combusting the solid fuel to produce an ash slag, wherein at least one ash fusion temperature characteristic selected from the group consisting of initial deformation temperature, softening temperature, hemispherical temperature, and fluid temperature is less than the same ash fusion temperature characteristic of a second ash slag produced from combustion of the solid fuel alone;
- and
- (ii) at least partially combusting the solid fuel to produce an ash slag, wherein at least a portion of the iron bearing material fluxes the ash slag to produce a composite ash slag having a melting point less than the melting point of ash slag produced from the combustion of the solid fuel alone.
A method of operating a solid fuel fired boiler, comprising:
- introducing a solid fuel into at least one of a slag-type furnace and a wet-bottom boiler;
- introducing an iron-bearing material into the at least one of a slag-type furnace and a wet-bottom boiler, wherein the iron bearing material is at least one of mill scale from steel production, and dust from blast furnace gas cleaning equipment;
- and
- at least partially combusting the solid fuel to produce an ash slag, wherein in the at least partially combusting step at least one of the following is true:
- (i) at least a portion of the iron bearing material fluxes the ash slag to produce a composite ash slag having at least one ash fusion temperature characteristic selected from the group consisting of initial deformation temperature, softening temperature, hemispherical temperature, and fluid temperature less than the same ash fusion temperature characteristic of the ash slag produced from combustion of the solid fuel alone;
- and
- (ii) at least a portion of the iron bearing material fluxes the ash slag to produce a composite ash slag having a melting point less than the melting point of ash slag produced from the combustion of the solid fuel alone.
The method of claim 31, wherein the carbon-containing compound is selected from the group consisting of a grease, an oil, and mixtures thereof.
Dependencies are inferred from the claim text.