Patent US4477708A successfully refreshed from Google Patents.
Patent US3607619A successfully refreshed from Google Patents.
US3607619A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Coking of black liquor in the absence of added free oxygen
Assignee: Texaco Inc
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Filing: 1968-11-29
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Granted: 1971-09-21
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Expires: 1988-11-29
Abstract
Abstract Process for treatment of black liquors from kraft pulp mills wherein black liquor is heated, in the absence of added free oxygen, under pressure at a temperature in the range of 450 to 700* F. for a period of 0.5 minutes to 6 hours to form a solid granular coke product which is separated from the resulting liquid to yield an aqueous liquid effluent suitable for reuse in the pulp making process.
Inventors
- 👤 Howard V Hess
- 👤 Edward L Cole
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 02:18
CPC Classifications
C; C02; C02F; C02F11/00; C02F11/10; C02F2103/00; C02F2103/26; C02F2103/28; Y; Y02; Y02W; Y02W10/00; Y02W10/40
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
58 words
The process defined in claim 1 comprising continuously introducing said waste liquor into a coking zone of relatively large volume at a rate sufficient to maintain an average residence time of liquor in said zone at said temperature and pressure in the range of one to 6 hours and continuously withdrawing said aqueous effluent from said coking zone.
Claim 2
Dependent Claim
96 words
The process as defined in claim 1 comprising heating said liquor to between about 450* and 625*, introducing said heated liquor at a given point in a vertical cooling zone to produce coke and gas therein, withdrawing said gas from the uppermost portion of said coking zone, withdrawing said coke from the lowermost portion of said coking zone and withdrawing an aqueous effluent containing soluble inorganic salts from said black liquor from the upper portion of said coking zone intermediate the point of introduction of said heated liquor and the point of withdrawal of said gas.
Claim 3
Dependent Claim
42 words
The process as defined in claim 1 comprising adding lime, sodium sulfate and sodium carbonate to said aqueous effluent to form cooking liquor for contact with wood chips at elevated temperature and pressure thus producing kraft process pulp and additional black liquor.
Claim 4
Dependent Claim
17 words
The process as defined in claim 4 comprising first concentrating said aqueous efflUent to remove excess water.
Claim 5
Dependent Claim
14 words
The process as defined in claim 5 wherein said concentration is effected by evaporation.
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) | 1974-09-20 | 1975-03-22 | 1975-09-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-09-20 | 1979-03-22 | 1979-09-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-09-20 | 1983-03-22 | 1983-09-21 | $7700.00 | Window Closed / Lapsed |