US4357207A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Low molecular weight cationic polymers as deposit inhibitors and dispersants in black liquor recovery systems
Assignee: ECC SPECIALTY CHEMICALS Inc
•
Filing: 1981-06-01
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Granted: 1982-11-02
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Expires: 2001-06-01
Abstract
Abstract The instant invention is directed to a method of inhibiting and dispersing deposit formation on metal surfaces of an evaporator used for the processing of black liquor which comprises the step of treating black liquor, at any point prior to completion of said processing, with a deposit inhibiting concentration of low molecular weight cationic polymer selected from the group consisting of poly(diallyldimethylammonium chloride), polymethacrylamidopropyltrimethylammonium chloride, poly-2-methacryloxyethyltrimethylammonium methosulfate, and poly-2-methacryloxyethyltrimethylammonium chloride.
Inventors
- 👤 Monica A. Yorke
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 00:05
CPC Classifications
C; C02; C02F; C02F5/00; C02F5/08; C02F5/10; C02F5/12; Y; Y10; Y10S; Y10S159/00; Y10S159/13
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
51 words
A method of inhibiting and dispersing deposit formation on metal surfaces of an evaporator used for the processing of black liquor which comprises the step of treating the black liquor, at any point prior to completion of said processing, with a deposit inhibiting concentration of a low molecular weight poly(diallyldimethylammonium chloride).
Claim 2
Independent Claim
51 words
A method of inhibiting and dispersing deposit formation on metal surfaces of an evaporator used for the processing of black liquor which comprises the step of treating the black liquor, at any point prior to completion of said processing, with a deposit inhibiting concentration of a low molecular weight poly(diallyldimethylammonium chloride).
Claim 3
Independent Claim
66 words
A method of inhibiting and dispersing deposit formation on metal surfaces of an evaporator used for the processing of black liquor which comprises the step of treating the black liquor, at any point prior to completion of said processing, with a deposit inhibiting concentration of a low molecular weight cationic polymer selected from the group consisting of poly(diallyldimethylammonium chloride), polymethacrylamidopropyltrimethylammonium chloride, poly-2-methacryloxyethyltrimethylammonium methosulfate, and poly-2-methacryloxyethyltrimethylammonium chloride.
Claim 4
Independent Claim
66 words
A method of inhibiting and dispersing deposit formation on metal surfaces of an evaporator used for the processing of black liquor which comprises the step of treating the black liquor, at any point prior to completion of said processing, with a deposit inhibiting concentration of a low molecular weight cationic polymer selected from the group consisting of poly(diallyldimethylammonium chloride), polymethacrylamidopropyltrimethylammonium chloride, poly-2-methacryloxyethyltrimethylammonium methosulfate, and poly-2-methacryloxyethyltrimethylammonium chloride.
Claim 5
Dependent Claim
21 words
The process of claim 2, wherein said low molecular weight cationic polymer has a molecular weight of about 2,000 to 50,000.
Claim 6
Dependent Claim
28 words
The process of claim 2, wherein said low molecular weight cationic polymer is added at 50 to 500 ppm concentration to 30 to 50 percent black liquor solids.
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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) | 1985-11-01 | 1986-05-03 | 1986-11-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1989-11-01 | 1990-05-03 | 1990-11-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1993-11-01 | 1994-05-03 | 1994-11-02 | $7700.00 | Window Closed / Lapsed |