US4197090A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for removing sulfur from coal
Assignee: Atlantic Richfield Co
•
Filing: 1978-02-10
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Granted: 1980-04-08
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Expires: 1998-02-10
Abstract
Abstract A process for reducing the pyritic sulfur content of coal comprising the steps of: (1) contacting an aqueous slurry of water and pyrite-containing coal particles at elevated temperature with oxygen, the contacting of step 1 being such that without step 2 the aqueous slurry would have a pH of less than 5.5; (2) maintaining the aqueous slurry of step 1 at a pH of from about 5.5 to 12.0; and (3) recovering coal particles of reduced pyritic sulfur content.
Inventors
- 👤 Jin S. Yoo
- 👤 Emmett H. Burk, Jr.
- 👤 John A. Karch
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 09:00
CPC Classifications
C; C10; C10L; C10L9/00; C10L9/02
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
56 words
A process for reducing the pyritic sulfur content of coal comprising: (1) contacting an aqueous slurry of water and pyrite-containing coal particles at elevated temperature with oxygen; (2) maintaining the aqueous slurry of step 1 at a pH of from about 5.5 to 12.0; and (3) separating water containing dissolved sulfur compounds from the coal particles.
Claim 2
Dependent Claim
56 words
A process for reducing the pyritic sulfur content of coal comprising: (1) contacting an aqueous slurry of water and pyrite-containing coal particles at elevated temperature with oxygen; (2) maintaining the aqueous slurry of step 1 at a pH of from about 5.5 to 12.0; and (3) separating water containing dissolved sulfur compounds from the coal particles.
Claim 3
Dependent Claim
17 words
The process of claim 1 wherein the pH in step 2 is from about 6.5 to 10.
Claim 4
Dependent Claim
17 words
The process of claim 1 wherein the temperature is from about 150° F. to about 350° F.
Claim 5
Dependent Claim
19 words
The process of claim 1 wherein the oxygen is at a pressure of from about 50 to 500 psig.
Claim 6
Dependent Claim
13 words
The process of claim 4 wherein oxygen gas is mixed with inert gas.
Claim 7
Dependent Claim
19 words
The process of claim 3 wherein the pH is maintained by adding an alkali material to the aqueous slurry.
Claim 8
Dependent Claim
29 words
The process of claim 6 wherein the alkali material is selected from the group consisting of potassium hydroxide, sodium hydroxide, potassium bicarbonate, sodium bicarbonate, ammonium bicarbonate and mixtures thereof.
Claim 9
Dependent Claim
24 words
The process of claim 3 wherein the aqueous slurry of water and coal particles contains from about 5 to 50%, by weight, coal particles.
Claim 10
Dependent Claim
24 words
The process of claim 8 wherein the aqueous slurry of water and coal particles contains from about 10 to 30%, by weight, coal particles.
Claim 11
Dependent Claim
17 words
The process of claim 3 wherein the coal particles have a particle size less than 5 mesh.
Claim 12
Dependent Claim
17 words
The process of claim 10 wherein the coal particles have a particle size less than 18 mesh.
References Cited (Backward Citations)
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Cited
US2346151A
Cited
US3824084A
Cited
US3909211A
Cited
US3960513A
Cited
US4054420A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1983-04-08 | 1983-10-08 | 1984-04-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-04-08 | 1987-10-08 | 1988-04-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-04-08 | 1991-10-08 | 1992-04-08 | $7700.00 | Window Closed / Lapsed |