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US 2011/0030592 A1Published application
Additives for mercury oxidation in coal-fired power plants
AssigneeADA Environmental Solutions, LLC
InventorsKenneth E. Baldrey, Sharon Sjostrom, Nina Bergan French, Michael D. Durham, Stephen Allen Johnson, John Wurster, John Philip Corner
Life of this patent
Estimating the term…
Abstract
The present invention is directed to an additive, primarily for low sulfur and high alkali coals, that includes a transition metal and optionally a halogen to effect mercury oxidation.
Claims37
A composition, comprising:
- (a) a low sulfur and high alkali coal, the coal feed comprises less than about 1.5 wt. % sulfur (dry basis of the coal) and at least about 20 wt. % (dry basis of ash from the coal) alkali;
- and
- (b) an additive comprising:
- i) ferrous iron,
- ii) ferric iron, wherein a ratio of ferric and higher valence iron to ferrous and lower valence iron in the additive is less than about 2:1;
- and
- iii) a halogen-containing compound other than a chlorine compound, the additive comprising at least about 0.005 wt. % (dry basis of the additive) of the halogen-containing compound.
4 more elements
A composition, comprising:
- (a) a low sulfur and high alkali coal, the coal feed comprises less than about 1.5 wt. % sulfur (dry basis of the coal) and at least about 20 wt. % (dry basis of ash from the coal) alkali;
- and
- (b) an additive comprising:
- i) at least about 50 wt. % (dry basis of the additive) ferric and ferrous iron,
- ii) no more than about 0.5 wt. % (dry basis sulfur of the additive);
- and
- iii) at least about 0.1 wt. % (dry basis of the additive) halogen-containing compound other than a chlorine compound.
4 more elements
A method, comprising:
- (a) providing a coal feed, the coal feed comprising sulfur, alkali, and iron, wherein the sulfur content of the coal feed is no more than about 1.5 wt. % (dry basis of the coal) and the alkali content of the coal feed is at least about 20 wt. % (dry basis of ash from the coal);
- (b) combusting the coal feed, in the presence of an added halogen-containing compound, to form a slag;
- (c) contacting the coal feed, prior to combustion, with a free-flowing additive, the free-flowing additive comprising at least about 50 wt. % (dry basis additive) iron;
- and
- (d) collecting the slag, wherein the slag comprises from about 20 to about 35 wt. % (dry basis slag) silica oxides, from about 13 to about 20 wt. % (dry basis slag) aluminum oxides, and from about 18 to about 35 wt. % (dry basis slag) calcium oxides.
2 more elements
A method, comprising:
- (a) providing a coal feed, the coal feed comprising sulfur, alkali, and iron;
- and
- (b) combusting the coal feed, in a furnace, in the presence of an added halogen-containing compound, and at a combustion temperature ranging from about 2,600 to about 3,000° F., to form a flue gas containing ash, wherein the sulfur content of the coal feed is no more than about 1.5 wt. % (dry basis of the coal) and the alkali content of the ash is at least about 20 wt. % (dry basis of the ash).
Dependencies are inferred from the claim text.