US4302209A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Lignite pellets and methods of agglomerating or pelletizing
Assignee: United States Department of Energy
•
Filing: 1979-07-30
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Granted: 1981-11-24
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Expires: 1999-07-30
Abstract
Abstract The specification discloses lignite pellets which are relatively hard, dust resistant, of generally uniform size and free from spontaneous ignition and general degradation. Also disclosed are methods for making such pellets which involve crushing as mined lignite, mixing said lignite with a binder such as asphalt, forming the lignite binder mixture into pellets, and drying the pellets.
Inventors
- 👤 Albert F. Baker
- 👤 Eric W. Blaustein
- 👤 Albert W. Deurbrouck
- 👤 John P. Garvin
- 👤 Robert E. McKeever
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 16:12
CPC Classifications
C; C10; C10L; C10L5/00; C10L5/02; C10F; C10F7/00
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
137 words
A process for producing lignite fuel pellets of high compressive strength comprising the steps of: crushing as mined lignite to a size suitable for pelletizing; predrying said lignite to a moisture content which allows fluid replacement; prewetting said crushed and dried lignite with water; mixing said prewetted lignite with a binder comprising an asphalt and water emulsion in an amount sufficient on pelletizing and drying to provide strength for handling and shipping; feeding the mixture of lignite and binder along with water to a pelletizing device having an inclined rotatable surface for receiving said mixture and water; forming moist pellets of said mixture including lignite with asphalt and water emulsion by rotating said surface to cause a tumbling, cascading action and the adhesion of particles into pellet form; and drying said pellets to a predetermined moisture level.
Claim 2
Dependent Claim
137 words
A process for producing lignite fuel pellets of high compressive strength comprising the steps of: crushing as mined lignite to a size suitable for pelletizing; predrying said lignite to a moisture content which allows fluid replacement; prewetting said crushed and dried lignite with water; mixing said prewetted lignite with a binder comprising an asphalt and water emulsion in an amount sufficient on pelletizing and drying to provide strength for handling and shipping; feeding the mixture of lignite and binder along with water to a pelletizing device having an inclined rotatable surface for receiving said mixture and water; forming moist pellets of said mixture including lignite with asphalt and water emulsion by rotating said surface to cause a tumbling, cascading action and the adhesion of particles into pellet form; and drying said pellets to a predetermined moisture level.
Claim 3
Dependent Claim
30 words
A process as claimed in claim 2 wherein the lignite is reduced to minus 10 mesh and pellets of about 3/4 inch are formed of said lignite and binder mixture.
Claim 4
Dependent Claim
18 words
The process of claim 1 wherein the lignite is simultanteously crushed and pre-dried in air swept milling equipment.
Claim 5
Dependent Claim
14 words
A process as claimed in claim 1 wherein the pelletizer is a disk pelletizer.
Claim 6
Dependent Claim
14 words
A process as claimed in claim 1 wherein the pelletizer is a balling drum.
Claim 7
Dependent Claim
23 words
A process as claimed in claim 1 wherein the pellets are dried in circulating air at a temperature up to about 500° F.
Claim 8
Dependent Claim
16 words
A process as claimed in claim 6 wherein the air is circulated in reversable air streams.
Claim 9
Dependent Claim
19 words
A process as claimed in claim 1 wherein the dried pellets are coated with an outer film of emulsion.
Claim 10
Dependent Claim
16 words
A process as claimed in claim 8 wherein the film of emulsion is applied by spraying.
Claim 11
Dependent Claim
31 words
A process as claimed in claim 1 wherein the pellets are dried to a moisture content of about 15% to 30% with heated air in the range 300° to 600° F.
Claim 12
Dependent Claim
33 words
The process of claim 1 also comprising the step of contacting said crushed lignite with a solution of sulfuric acid to exchange hydrogen ions for sodium ions thereby removing sodium from the lignite.
Claim 13
Dependent Claim
30 words
The process of claim 11 wherein sufficient amount of sodium are removed to make the sodium content of the lignite lower than 4% of the ash content of the lignite.
Claim 14
Dependent Claim
24 words
The process of claim 1 wherein additional water is sprayed onto said mixture of lignite and asphalt and water emulsion while forming pellets thereof.
Claim 15
Dependent Claim
18 words
The process of claim 1 wherein said pellets are dried to a moisture content of 15 to 30%.
Claim 16
Dependent Claim
18 words
The process of claim 14 wherein said pellets are dried to a moisture content of 15 to 20%.
References Cited (Backward Citations)
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1984-11-23 | 1985-05-25 | 1985-11-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-11-23 | 1989-05-25 | 1989-11-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-11-23 | 1993-05-25 | 1993-11-24 | $7700.00 | Window Closed / Lapsed |