US3976747A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Modified dry limestone process for control of sulfur dioxide emissions
Assignee: Energy Research and Development Administration ERDA
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Filing: 1975-06-06
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Granted: 1976-08-24
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Expires: 1995-06-06
Abstract
Abstract A method and apparatus for removing sulfur oxides from flue gas comprise cooling and conditioning the hot flue gas to increase the degree of water vapor saturation prior to passage through a bed of substantially dry carbonate chips or lumps, e.g., crushed limestone. The reaction products form as a thick layer of sulfites and sulfates on the surface of the chips which is easily removed by agitation to restore the reactive surface of the chips.
Inventors
- 👤 Correll C. Shale
- 👤 William G. Cross
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 09:08
CPC Classifications
B; B01; B01D; B01D53/00; B01D53/34; B01D53/46; B01D53/48; B01D53/50; B01D53/508
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
124 words
A method of desulfurizing flue gas comprising conditioning said flue gas to a temperature no lower than about 100°F and to substantially complete water vapor saturation and contacting the conditioned flue gas with a substantially dry bed of scrubbing medium to cause the condensation of water on the bed, said scrubbing medium comprising pieces of material larger than 1/16 inch said material selected from the group of mono-bi-and trivalent metal carbonates and bicarbonates, to cause sulfur oxides present in said flue gas to react with subsurface molecules of the scrubbing medium forming a layer of reaction products thicker than about 1/32 inch on the scrubbing medium, and periodically removing said reaction products from the scrubbing medium by mechanical means to expose a reactive surface.
Claim 2
Independent Claim
124 words
A method of desulfurizing flue gas comprising conditioning said flue gas to a temperature no lower than about 100°F and to substantially complete water vapor saturation and contacting the conditioned flue gas with a substantially dry bed of scrubbing medium to cause the condensation of water on the bed, said scrubbing medium comprising pieces of material larger than 1/16 inch said material selected from the group of mono-bi-and trivalent metal carbonates and bicarbonates, to cause sulfur oxides present in said flue gas to react with subsurface molecules of the scrubbing medium forming a layer of reaction products thicker than about 1/32 inch on the scrubbing medium, and periodically removing said reaction products from the scrubbing medium by mechanical means to expose a reactive surface.
Claim 3
Dependent Claim
45 words
The method of claim 1 further comprising removing partially reacted scrubbing medium from the bed, treating the partially reacted scrubbing medium to remove the layer of reaction products and restore a reactive surface, and returning the treated scrubbing medium to the bed for further use.
Claim 4
Dependent Claim
23 words
The method of claim 1 wherein said scrubbing medium comprises a material selected from the group of MgCO 3 and CaCO 3 .
Claim 5
Dependent Claim
40 words
The method of claim 3 wherein said flue gas is conditioned to a temperature above its water vapor saturation temperature and the conditioned flue gas is cooled to release condensate as said flue gas contacts the bed of scrubbing medium.
Claim 6
Dependent Claim
16 words
The method of claim 3 wherein said conditioning step comprises cooling said flue gas to 140°-180°F.
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) | 1979-08-24 | 1980-02-23 | 1980-08-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-08-24 | 1984-02-23 | 1984-08-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-08-24 | 1988-02-23 | 1988-08-24 | $7700.00 | Window Closed / Lapsed |