US4097244A
Expired / Lapsed
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Process for removing sulfur from coal
Assignee: Atlantic Richfield Co
•
Filing: 1976-12-13
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Granted: 1978-06-27
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Expires: 1996-12-13
Abstract
Abstract A process for reducing the sulfur content of coal comprising the steps of:
Inventors
- 👤 Emmett H. Burk, Jr.
- 👤 Jin S. Yoo
- 👤 John A. Karch
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 05:55
CPC Classifications
C; C10; C10L; C10L9/00; C10L9/02
Claims Analysis
Total Claims: 35
Claim 1
Independent Claim
68 words
A process for reducing the sulfur content of coal comprising the steps of: 1. contacting coal particles with an aqueous solution of iron complexing agent, and an oxidant to preferentially oxidize at least a portion of the sulfur in the coal; 2. thermally treating the oxidized sulfur-containing coal at elevated temperatures to reduce the sulfur content of the coal; and 3. recovering coal particles of reduced sulfur content.
Claim 2
Dependent Claim
68 words
A process for reducing the sulfur content of coal comprising the steps of: 1. contacting coal particles with an aqueous solution of iron complexing agent, and an oxidant to preferentially oxidize at least a portion of the sulfur in the coal; 2. thermally treating the oxidized sulfur-containing coal at elevated temperatures to reduce the sulfur content of the coal; and 3. recovering coal particles of reduced sulfur content.
Claim 3
Dependent Claim
18 words
The process of claim 1 wherein the aqueous solution of iron complexing agent is maintained at elevated temperature.
Claim 4
Dependent Claim
10 words
The process of claim 2 wherein the oxidant is oxygen.
Claim 5
Dependent Claim
19 words
The process of claim 3 wherein the oxygen is maintained at a pressure of from 5 to 500 psig.
Claim 6
Dependent Claim
26 words
The process of claim 4 wherein the aqueous solution of iron complexing agent is maintained at an elevated temperature from about 150° F. to 400° F.
Claim 7
Dependent Claim
26 words
The process of claim 5 wherein the iron complexing agent is present in a mole ratio of iron complexing agent to pyrite of 0.5 to 10.
Claim 8
Dependent Claim
29 words
The process of claim 6 wherein the iron complexing agent is a compound which forms ferrous or ferric complexes having a stability constant -log K of more than 1.
Claim 9
Dependent Claim
15 words
The process of claim 7 wherein the stability constant -log K is greater than 2.
Claim 10
Dependent Claim
17 words
The process of claim 8 wherein the pressure of oxygen is from about 25 to 400 psig.
Claim 11
Dependent Claim
17 words
The process of claim 9 wherein the pressure of oxygen is from about 50 to 300 psig.
Claim 12
Dependent Claim
16 words
The process of claim 10 wherein the temperature is from about 175° F. to 350° F.
Claim 13
Dependent Claim
56 words
The process of claim 11 wherein the complexing agent is selected from the group consisting of carboxylic acids, and hydroxy carboxylic acids and their salts, diols and polyols, amines, amino acids and amino acid salts, amino polycarboxylic acids and amino polycarboxylic acid salts, phosphonic acids and phosphonic acid salts, condensed phosphates, and salts of condensed phosphates.
Claim 14
Dependent Claim
14 words
The process of claim 12 wherein the salts are alkali metal and ammonium salts.
Claim 15
Dependent Claim
23 words
The process of claim 13 wherein the complexing agent is selected from the group consisting of sodium oxalate, potassium oxalate and ammonium oxalate.
Claim 16
Dependent Claim
19 words
The process of claim 2 wherein the oxidant is selected from the group consisting of ozone and singlet oxygen.
Claim 17
Dependent Claim
24 words
The process of claim 2 wherein the oxidant is an organic oxidant selected from the group consisting of hydrocarbon peroxides, hydrocarbon hydroperoxides and peracids.
Claim 18
Dependent Claim
21 words
The process of claim 2 wherein the oxidant is an inorganic oxidant selected from the group consisting of peroxides and superoxides.
Claim 19
Dependent Claim
21 words
The process of claim 1 wherein thermally treating the oxidized sulfur-containing coal at elevated temperature involves exposing the coal to steam.
Claim 20
Dependent Claim
22 words
The process of claim 1 wherein thermally treating the oxidized sulfur-containing coal involves heating an aqueous slurry of coal to elevated temperature.
Claim 21
Dependent Claim
11 words
The process of claim 17 wherein the oxidant is hydrogen peroxide.
Claim 22
Dependent Claim
82 words
A process for reducing the sulfur content of coal comprising the steps of: 1. contacting coal particles with an aqueous solution of iron complexing agent, and an oxidant to preferentially oxidize at least a portion of the sulfur in the coal; 2. subjecting the oxidized sulfur-containing coal to a base thermal treatment comprising heating an aqueous slurry of the coal and base to elevated temperature to reduce the sulfur content of the coal; and 3. recovering coal particles of reduced sulfur content.
Claim 23
Dependent Claim
82 words
A process for reducing the sulfur content of coal comprising the steps of: 1. contacting coal particles with an aqueous solution of iron complexing agent, and an oxidant to preferentially oxidize at least a portion of the sulfur in the coal; 2. subjecting the oxidized sulfur-containing coal to a base thermal treatment comprising heating an aqueous slurry of the coal and base to elevated temperature to reduce the sulfur content of the coal; and 3. recovering coal particles of reduced sulfur content.
Claim 24
Dependent Claim
18 words
The process of claim 19 wherein the aqueous solution of iron complexing agent is maintained at elevated temperature.
Claim 25
Dependent Claim
10 words
The process of claim 22 wherein the oxidant is oxygen.
Claim 26
Dependent Claim
19 words
The process of claim 23 wherein the oxygen is maintained at a pressure of from 5 to 500 psig.
Claim 27
Dependent Claim
26 words
The process of claim 24 wherein the aqueous solution of iron complexing agent is maintained at an elevated temperature from about 150° F. to 400° F.
Claim 28
Dependent Claim
26 words
The process of claim 25 wherein the iron complexing agent is present in a mole ratio of iron complexing agent to pyrite of 0.5 to 10.
Claim 29
Dependent Claim
29 words
The process of claim 26 wherein the iron complexing agent is a compound which forms ferrous or ferric complexes having a stability constant -log K of more than 1.
Claim 30
Dependent Claim
11 words
The process of claim 25 wherein the oxidant is hydrogen peroxide.
Claim 31
Dependent Claim
21 words
The process of claim 21 wherein the base is selected from the group consisting of alkali and alkaline earth metal hydroxides.
Claim 32
Dependent Claim
16 words
The process of claim 19 wherein the aqueous slurry has a pH of greater than 7.
Claim 33
Dependent Claim
30 words
The process of claim 21 wherein the base is selected from the group consisting of potassium hydroxide, sodium hydroxide, calcium hydroxide, potassium carbonate, sodium carbonate, calcium carbonate and calcium oxide.
Claim 34
Dependent Claim
12 words
The process of claim 1 wherein the recovered coal is metallurgical coal.
Claim 35
Dependent Claim
12 words
The process of claim 21 wherein the recovered coal is metallurgical coal.
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) | 1981-06-26 | 1981-12-26 | 1982-06-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-06-26 | 1985-12-26 | 1986-06-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-06-26 | 1989-12-26 | 1990-06-27 | $7700.00 | Window Closed / Lapsed |