US3966431A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Waste stone oxidation and recarbonization
Assignee: Environmental Protection Agency
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Filing: 1975-02-21
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Granted: 1976-06-29
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Expires: 1995-02-21
Abstract
Abstract The disclosed process provides for the production of a desulfurized fuel gas from a sulfur-containing fuel oil by absorption, in a first reaction zone, of the sulfur contaminants with a calcium oxide-containing material, which material is then further treated to render it environmentally stable without producing a sulfur-rich gas process stream. The spent limestone from the oil gasifier is reacted with an oxygen-containing gas in a second reaction zone for conversion of the calcium sulfide to calcium sulfate and the sulfated material is then transferred to a third reaction zone wherein it is reacted with carbon dioxide for conversion of the calcium oxide to calcium carbonate.
Inventors
- 👤 John W. T. Craig
- 👤 Eoin P. O'Neill
- 👤 Dale L. Keairns
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 01:00
CPC Classifications
C; C10; C10K; C10K1/00; C10K1/20
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
164 words
A process for the desulfurization and gasification of a sulfur-containing fuel comprising: contacting said sulfur-containing fuel with a particulate calcium oxide-containing material, in a first reaction zone, at a temperature sufficient to gasify said fuel and to cause the sulfur contained therein to react with the calcium oxide to form calcium sulfide coatings on the particles and to produce a fuel gas overhead of reduced sulfur content; transferring said calcium sulfide-coated particles from said first reaction zone to a second reaction zone, wherein said particles are contacted with a free oxygen-containing gas at a temperature suffficient to convert at least a portion of said calcium sulfide to calcium sulfate, thereby forming sulfated particles; transferring said sulfated particles to a third reaction zone wherein said sulfated particles are contacted with a carbon dioxide-containing gas to convert at least a portion of the calcium oxide contained in said sulfated particles into calcium carbonate, thus forming an environmentally stable particulate material comprising calcium sulfate and calcium carbonate.
Claim 2
Dependent Claim
164 words
A process for the desulfurization and gasification of a sulfur-containing fuel comprising: contacting said sulfur-containing fuel with a particulate calcium oxide-containing material, in a first reaction zone, at a temperature sufficient to gasify said fuel and to cause the sulfur contained therein to react with the calcium oxide to form calcium sulfide coatings on the particles and to produce a fuel gas overhead of reduced sulfur content; transferring said calcium sulfide-coated particles from said first reaction zone to a second reaction zone, wherein said particles are contacted with a free oxygen-containing gas at a temperature suffficient to convert at least a portion of said calcium sulfide to calcium sulfate, thereby forming sulfated particles; transferring said sulfated particles to a third reaction zone wherein said sulfated particles are contacted with a carbon dioxide-containing gas to convert at least a portion of the calcium oxide contained in said sulfated particles into calcium carbonate, thus forming an environmentally stable particulate material comprising calcium sulfate and calcium carbonate.
Claim 3
Dependent Claim
38 words
The process of claim 1 wherein said first, second, and third reaction zones contain beds of a particulate calcium oxide containing material fluidized by a fluid selected from a free oxygen-containing gas, flue gases, steam, and mixtures thereof.
Claim 4
Dependent Claim
44 words
The process of claim 2 wherein said first zone is maintained at a temperature within the range of 820°-920°C, said second zone is maintained at a temperature below about 850°C, and said third zone is maintained at a temperature within the range of 710°-770°C.
Claim 5
Dependent Claim
44 words
The process of claim 2, wherein the average particle size of the calcium oxide-containing material within the first zone is 300-3000 microns and wherein the average particle size is reduced to less than 100 microns by means of jet attrition within said second zone.
Claim 6
Dependent Claim
23 words
The process of claim 1 wherein at least one of said zones is provided with staged beds of said particulate calcium oxide-containing material.
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) | 1979-06-29 | 1979-12-29 | 1980-06-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-06-29 | 1983-12-29 | 1984-06-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-06-29 | 1987-12-29 | 1988-06-29 | $7700.00 | Window Closed / Lapsed |