Patent US3598717A successfully refreshed from Google Patents.
US3598717A
Expired / Lapsed
US
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Method for liquefying coal
Assignee: Universal Oil Products Co
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Filing: 1968-06-25
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Granted: 1971-08-10
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Expires: 1988-06-25
Abstract
Abstract A TWO-STAGE SOLVENT EXTRACTION METHOD FOR CONVERTING SOLID COAL INTO LIQUID COAL EXTRACT. THE FIRST STAGE USES THE CONVENTIONAL SOLVENTS, SUCH AS POLYAROMATIC HYDROCARBONS ALKYLNAPHTHALENES, ANTHRACENE OIL, OR PARTIALLY HYDROGENATED AROMATICS AS FOR INSTANCE, TETRALIN. THE LIQUEFIED COAL STRIPPED OF THE SOLVENT IS THEN EXTRACTED WITH A KETONE TO PRODUCE A HYDROGEN-RICH EXTRACT FRACTION AND A HYDROGEN LEAN EXTRACT PHASE. THE HYDROGEN-RICH FRACTION IS RECOVERED AND USED AS A SOURCE FOR VALUABLE CHEMICALS AND LIQUID FUELS. THE HYDROGEN-LEAN FRACTION MAY BE USED FOR PLANT FUEL AND/OR AS A SOURCE FOR ADDITIONAL HYDROGEN THROUGH CONVERSION BY THE "WATER-GAS" REACTION.
Inventors
- 👤 George R Sunagel
- 👤 Richard S Corey
- 👤 Frederick J Riedl
- 👤 William K T Gleim
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 01:37
CPC Classifications
C; C10; C10G; C10G1/00; C10G1/002; C10G1/006
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-08-09 | 1975-02-08 | 1975-08-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-08-09 | 1979-02-08 | 1979-08-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-08-09 | 1983-02-08 | 1983-08-10 | $7700.00 | Window Closed / Lapsed |