Patent US3914378A successfully refreshed from Google Patents.
US3914378A
Expired / Lapsed
US
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Process for wet scrubbing of sulfur dioxide from flue gas
Assignee: Dravo Lime Co
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Filing: 1974-03-13
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Granted: 1975-10-21
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Expires: 1994-03-13
Abstract
Abstract A process for removing sulfur dioxide from flue gas by a wet scrubbing system having a demister unit and wherein addition of a specified amount of magnesium ion to the lime scrubbing slurry is made, with the thickener overflow used as demister water without substantial scaling or solid deposition. A resultant higher efficiency of the scrubber is achieved with fresh water added to the system usable to slake the lime-magnesium slurry used to replenish the scrubbing liquor.
Inventors
- 👤 Joseph G Selmeczi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 22:05
CPC Classifications
C; C01; C01F; C01F11/00; C01F11/46; C01F11/464; B; B01; B01D; B01D53/00; B01D53/34; B01D53/46; B01D53/48; B01D53/50; B01D53/501; C01F11/48; C01F5/00; C01F5/42
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
128 words
IN A PROCESS FOR REMOVING SULFUR DIOXIDE FROM A GASEOUS STREAM IN A WET SCRUBBING UNIT HAVING A CONTACT ZONE AND MEANS FOR DEMISTING THE GASEOUS STREAM WHEREIN THE GASEOUS STREAM IS CONTACTED WITH AN AQUEOUS LIQUOR CONTAINING CALCIUM SALTS AND A MAGNESIUM ION CONTENT OF ABOUT 250-5000 PARTS PER MILLION, AND WHEREIN A PORTION OF THE AQUEOUS EFFLUENT IS RECYCLED TO THE SCRUBBING UNIT WHILE A FURTHER PORTION THEREOF IS PASSED TO THICKENER UNIT TO PRECIPITATE SALTS THEREFROM AN PRODUCE A CLARIFIED THICKENER OVERFLOW, THE IMPRVEMENT COMPRISING PASSING THE CLARIFIED THICKENER OVERFLOW FROM THE THICKENER UNIT TO SAID MEANS FOR DEMISTING THE GASEOUS STREAM, AND DIRECTING SAID CLARIFIED THICKENER OVERFLOW ONTO SAID MEANS FOR DEMISTING THE GASEOUS STREAM TO WASH THE SAME AND PREVENT SOLIDS BUILDUP THEREON.
Claim 2
Dependent Claim
128 words
IN A PROCESS FOR REMOVING SULFUR DIOXIDE FROM A GASEOUS STREAM IN A WET SCRUBBING UNIT HAVING A CONTACT ZONE AND MEANS FOR DEMISTING THE GASEOUS STREAM WHEREIN THE GASEOUS STREAM IS CONTACTED WITH AN AQUEOUS LIQUOR CONTAINING CALCIUM SALTS AND A MAGNESIUM ION CONTENT OF ABOUT 250-5000 PARTS PER MILLION, AND WHEREIN A PORTION OF THE AQUEOUS EFFLUENT IS RECYCLED TO THE SCRUBBING UNIT WHILE A FURTHER PORTION THEREOF IS PASSED TO THICKENER UNIT TO PRECIPITATE SALTS THEREFROM AN PRODUCE A CLARIFIED THICKENER OVERFLOW, THE IMPRVEMENT COMPRISING PASSING THE CLARIFIED THICKENER OVERFLOW FROM THE THICKENER UNIT TO SAID MEANS FOR DEMISTING THE GASEOUS STREAM, AND DIRECTING SAID CLARIFIED THICKENER OVERFLOW ONTO SAID MEANS FOR DEMISTING THE GASEOUS STREAM TO WASH THE SAME AND PREVENT SOLIDS BUILDUP THEREON.
Claim 3
Dependent Claim
24 words
In the process defined in claim 1, the improvement wherein the sole supply of water fed to said demister comprises said clarified thickener overflow.
Claim 4
Dependent Claim
43 words
In the process defined in claim 1, the improvement wherein said clarified thickener overflow water is apportioned and one portion directed to the underside of said means for demisting the gaseous stream and a second portion is directed to the upper side thereof.
Claim 5
Dependent Claim
40 words
In the process defined in claim 1, the improvement wherein a portion of said clarified thickener overflow is directed to a slurry tank for use in dilution of the slaked calcium and magnesium hydroxides for use in said scrubbing liquor.
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) | 1978-10-20 | 1979-04-21 | 1979-10-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-10-20 | 1983-04-21 | 1983-10-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-10-20 | 1987-04-21 | 1987-10-21 | $7700.00 | Window Closed / Lapsed |