US3919393A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for sulfur dioxide removal from combustion gases
Assignee: Dravo Lime Co
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Filing: 1973-03-08
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Granted: 1975-11-11
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Expires: 1993-03-08
Abstract
Abstract An improved process for the removal of sulfur dioxide from gases resulting from combustion of sulfur-containing fuels such as coal, with the gases passed through a wet scrubber to which there is added an aqueous solution of calcium oxide containing 2-10% magnesium oxide, whereby the effeciency of sulfur dioxide removal in the scrubber is increased and scaling reduced therein.
Inventors
- 👤 Joseph G Selmeczi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 21:16
CPC Classifications
B; B01; B01D; B01D53/00; B01D53/34; B01D53/46; B01D53/48; B01D53/50; B01D53/501
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
101 words
IN A PROCESS FOR REMOVING SULFUR DIOXIDE FROM GASES REDULTING FROM THE COMBUSTION OF SULFUR-CONTAINING FUELS WHEREIN THE GASES ARE SUBJECTED TO A WET SCRUBBING STEP BY CONTACT WITH AN AQUEOUS SOLUTION OF CALCIUM OXIDE AND PORTION OF THE AQUEOUS SOLUTON PREVIOUSLY PASSED THROUGH SAID SCRUBBER AND CLARIFIED, WITH AN EFFLUENT REMOVED THEREFROM, THE IMPROVEMENT COMPRISING ELIMINATING THE FORMATION OF SCALE WITHIN SAID SCRUBBER WHILE MINIMIZING THE AMOUNT OF DISSOLVED MAGNESIUM SULFITE WITHIN THE EFFLUENT BY ADDING TO SAID AQUEOUS SOLUTION OF CALCIUM OXIDE 2-10% BY WEIGHT OF MAGNESIUM OXIDE, BASED ON THE TOTAL AMOUNT OF CALCIUM OXIDE AND MAGNESIUM OXIDE.
Claim 2
Dependent Claim
101 words
IN A PROCESS FOR REMOVING SULFUR DIOXIDE FROM GASES REDULTING FROM THE COMBUSTION OF SULFUR-CONTAINING FUELS WHEREIN THE GASES ARE SUBJECTED TO A WET SCRUBBING STEP BY CONTACT WITH AN AQUEOUS SOLUTION OF CALCIUM OXIDE AND PORTION OF THE AQUEOUS SOLUTON PREVIOUSLY PASSED THROUGH SAID SCRUBBER AND CLARIFIED, WITH AN EFFLUENT REMOVED THEREFROM, THE IMPROVEMENT COMPRISING ELIMINATING THE FORMATION OF SCALE WITHIN SAID SCRUBBER WHILE MINIMIZING THE AMOUNT OF DISSOLVED MAGNESIUM SULFITE WITHIN THE EFFLUENT BY ADDING TO SAID AQUEOUS SOLUTION OF CALCIUM OXIDE 2-10% BY WEIGHT OF MAGNESIUM OXIDE, BASED ON THE TOTAL AMOUNT OF CALCIUM OXIDE AND MAGNESIUM OXIDE.
Claim 3
Dependent Claim
28 words
The process defined in claim 1 wherein said aqueous solution is in the form of slaked lime and wherein said magnesium oxide is admixed with said slaked lime.
Claim 4
Dependent Claim
28 words
The process defined in claim 1 wherein said magnesium oxide is present in an amount of 4-8% based on the total amount of calcium oxide and magnesium oxide.
Claim 5
Dependent Claim
42 words
The process defined in claim 1 wherein said aqueous solution of calcium oxide containing said magnesium oxide is combined with said portion of the aqueous solution previously passed through said scrubber and clarified, and said combined solutions are charged to said scrubber.
Claim 6
Dependent Claim
27 words
The process defined in claim 1 wherein said sulfur containing fuel is coal, and said gases from said combustion contain fly ash in addition to sulfur dioxide.
Claim 7
Dependent Claim
13 words
The process defined in claim 1 wherein said sulfur containing fuel is oil.
Claim 8
Dependent Claim
19 words
The process defined in claim 1 wherein said gases containing sulfur dioxide are produced by smelting operations for ores.
Claim 9
Dependent Claim
34 words
The process defined in claim 1 wherein said aqueous solution containing said magnesium oxide in an amount of 2-10% by weight is formed by admixing dolomitic lime and high calcium lime in predetermined amounts.
Claim 10
Dependent Claim
51 words
The process defined in claim 1 wherein said aqueous solution containng said magnesium oxide in an amount of 2-10% by weight is formed by adding to water a lime product reSulting from calcining of limestone containing a predetermined amount of magnesium carbonate and calcium carbonate so as to produce said oxides.
Claim 11
Dependent Claim
46 words
The process defined in claim 1 wherein said aqueous solution containing said magnesium oxide in an amount of 2-10% by weight is formed by blending of dolomitic stone and high-calcium limestone to form a mixture and calcining said blended mixture so as to produce said oxides.
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) | 1978-11-10 | 1979-05-12 | 1979-11-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-11-10 | 1983-05-12 | 1983-11-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-11-10 | 1987-05-12 | 1987-11-11 | $7700.00 | Window Closed / Lapsed |