US3583900A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Coal liquefaction process by three-stage solvent extraction
Assignee: Universal Oil Products Co
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Filing: 1969-12-29
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Granted: 1971-06-08
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Expires: 1989-12-29
Abstract
Abstract COAL IS CONVERTED INTO VALUABLE LIQUID PRODUCTS UTILIZING A THREE-STAGE SOLVENT EXTRACTION PROCESS. THE COAL IS FIRST CONTACTED WITH A CONVENTIONAL COAL SOLVENT SUCH AS TETRAHYDRONAPHTHALENE, WITH THE RESULTING LIQUID COAL EXTRACT EXTRACTED WITH A FIRST ALIPHATIC SOLVENT TO PRODUCE AN ASPHALTENE FREE EXTRACT WITH THE RESULANT RESIDUE BEING TREATED WITH A LIGHT AROMATIC SOLVENT TO FURTHER PRODUCE A SECOND COAL EXTRACT. EACH OF THE EXTRACT MATERIALS ARE SEPARATELY REFINED, AND PRODUCED ARE COAL PRODUCTS FREE OF SOLID MATERIAL WITHOUT THE UTILIZATION OF INTRICATE FILTRATION PRINCIPLES.
Inventors
- 👤 John G Gatsis
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 18:33
CPC Classifications
C; C10; C10G; C10G1/00; C10G1/006; C10G1/002; C10G2300/00; C10G2300/10; C10G2300/107
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) | 1974-06-07 | 1974-12-07 | 1975-06-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-06-07 | 1978-12-07 | 1979-06-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-06-07 | 1982-12-07 | 1983-06-08 | $7700.00 | Window Closed / Lapsed |