US4262610A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of reducing the sulfur emissions from boilers fired with brown coal and, more generally, from boilers fired with low-rank solid fossil fuels and used in the production of electric power
Assignee: Wintershall Dea International AG
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Filing: 1979-06-08
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Granted: 1981-04-21
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Expires: 1999-06-08
Abstract
Abstract A method of reducing sulfur emissions in boilers fired with brown coal (as an example of low-rank solid fossil fuels with which the invention is usable) wherein finely divided calcium oxide (or calcium-oxide-containing dry materials) as additive is mixed with the fuel before the fuel is introduced into the combustion chamber of the boiler or the burner thereof. Advantageously the additive is mixed with the fuel before the milling thereof. The quantity of finely divided additive which is mixed with the fuel is varied in accordance with the sulfur concentration of the gases at the end of the combustion chamber, e.g. in response to a sulfur dioxide and/or sulfur trioxide sensor, to minimize the sulfur content of the flue gases.
Inventors
- 👤 Klaus Hein
- 👤 Ansgar Schiffers
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 18:20
CPC Classifications
F; F23; F23J; F23J7/00; C; C10; C10L; C10L9/00; C10L9/10
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
82 words
A method of reducing sulfur emissions in a boiler fired with low-rank coal as a fuel, especially for a power plant, which comprises the steps of: (a) mixing particulate calcium oxide with low-rank coal having a water content greater than about 20% by weight in a mill-drying stage wherein a mixture thereof is formed, comminuted and dried; (b) thereafter pneumatically introducing the mill-dried mixture into the firebox of the boiler through a burner thereof; and (c) burning said mixture in said firebox.
Claim 2
Independent Claim
82 words
A method of reducing sulfur emissions in a boiler fired with low-rank coal as a fuel, especially for a power plant, which comprises the steps of: (a) mixing particulate calcium oxide with low-rank coal having a water content greater than about 20% by weight in a mill-drying stage wherein a mixture thereof is formed, comminuted and dried; (b) thereafter pneumatically introducing the mill-dried mixture into the firebox of the boiler through a burner thereof; and (c) burning said mixture in said firebox.
Claim 3
Dependent Claim
60 words
The method defined in claim 1, further comprising the steps of: (d) measuring the gaseous sulfur oxide content of flue gases from said firebox prior to discharge of said flue gases into the atmosphere via a stack; and (e) controlling the quantity of the calcium oxide mixed with the low-rank coal in response to the measured gaseous sulfur oxide content.
Claim 4
Dependent Claim
27 words
The method defined in claim 2, further comprising the step of: (f) recovering calcium-containing solids from said flue gases by subjecting the flue gases to electrostatic precipitation.
Claim 5
Dependent Claim
45 words
The method defined in claim 3 wherein said calcium oxide is mixed with brown coal forming said low-rank coal in a slight stoichiometric excess of the calcium oxide over that which is required to react with all of the sulfur contained in the brown coal.
Claim 6
Dependent Claim
103 words
In a method of reducing sulfur emissions from electric power plant boiler fireboxes and in which a sulfur-containing coal is milled and used as the fuel and the fuel is mixed with fine-grained calcium oxide and the mixture is introduced into the firebox of the boiler, the sulfur from the fuel reacting with calcium oxide to form solid reaction products, the improvement wherein the coal combined with the calcium oxide as said fuel is brown coal and the brown coal is combined with the calcium oxide by mill drying them together before the mixture is penumatically introduced into the firebox of the boiler.
Claim 7
Dependent Claim
103 words
In a method of reducing sulfur emissions from electric power plant boiler fireboxes and in which a sulfur-containing coal is milled and used as the fuel and the fuel is mixed with fine-grained calcium oxide and the mixture is introduced into the firebox of the boiler, the sulfur from the fuel reacting with calcium oxide to form solid reaction products, the improvement wherein the coal combined with the calcium oxide as said fuel is brown coal and the brown coal is combined with the calcium oxide by mill drying them together before the mixture is penumatically introduced into the firebox of the boiler.
Claim 8
Dependent Claim
39 words
The improvement defined in claim 5, further comprising the step of controlling the amount of calcium oxide mixed with the brown coal in the mill drier in response to the sulfur oxide content of flue gases from said firebox.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1984-04-20 | 1984-10-20 | 1985-04-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-04-20 | 1988-10-20 | 1989-04-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-04-20 | 1992-10-20 | 1993-04-21 | $7700.00 | Window Closed / Lapsed |