Patent US3911084A successfully refreshed from Google Patents.
US3911084A
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Process for separating sulfur oxides from gas streams
Assignee: ONTARIO HYDRO A CORP CONTINUED UNDER POWER Corp ACT RSO 1980 CHAPT 384
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Filing: 1973-02-20
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Granted: 1975-10-07
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Expires: 1993-02-20
Abstract
Abstract Sulfur oxides, particularly sulfur dioxide, present in waste gas streams are separated therefrom by contacting the sulfur oxides with a sodium sulfite-sodium bisulfite extraction liquor having a pH of at least 6, regenerating a portion of the sulfur oxidescontaining extraction liquor by adding calcium hydroxide thereto to raise the pH of the liquor to about 8 to 10, removing a calcium sulfite precipitate from the regenerated extraction liquor, and mixing the solids-free regenerated extraction liquor with the sulfur oxides-containing extraction liquor to maintain its pH of at least 6.
Inventors
- 👤 Bruce Irving Wall
- 👤 Henry Clinton Harris
- 👤 Jose Luis Arnaud
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 19:57
CPC Classifications
B; B01; B01D; B01D53/00; B01D53/34; B01D53/46; B01D53/48; B01D53/50; B01D53/501
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
110 words
PROCESS FOR REMOVING GASEOUS SULFUR OXIDES FROM A GAS STREAM CONTAINING SAID SULFUR OXIDES WHICH COMPRISES THE STEPS OF PROVIDING A CIRCULATING AQUEOUS EXTRACTING SOLUTION CONTAINING SODIUM SULFITE AND SODIUM BISULFITE, AND HAVING A PH OF ABOUT 6 TO ABOUT 7, CONTACTING SAID GAS STREAM IN A GAS-LIQUID CONTACTOR WITH SAID CIRCULATING EXTRACTING SOLUTION TO FORM A LIQUID EXTRACT HAVING A RELATIVELY HIGHER SODIUM BISULFITE CONTENT AND A RELATIVELY LOWER PH, RECOVERING SAID EXTRACT, REGENERATING AT LEAST A PORTION OF THE SODIUM BISULFITE CONTENT OF SAID EXTRACT TO SODIUM SULFITE BY TREATMENT IN A SINGLE REGENERATION STEP WITH A CALCIUM COMPOUND SELECTED FROM THE GROUP CONSISTING OF CALCIUM OXIDE AND
Claim 2
Dependent Claim
110 words
PROCESS FOR REMOVING GASEOUS SULFUR OXIDES FROM A GAS STREAM CONTAINING SAID SULFUR OXIDES WHICH COMPRISES THE STEPS OF PROVIDING A CIRCULATING AQUEOUS EXTRACTING SOLUTION CONTAINING SODIUM SULFITE AND SODIUM BISULFITE, AND HAVING A PH OF ABOUT 6 TO ABOUT 7, CONTACTING SAID GAS STREAM IN A GAS-LIQUID CONTACTOR WITH SAID CIRCULATING EXTRACTING SOLUTION TO FORM A LIQUID EXTRACT HAVING A RELATIVELY HIGHER SODIUM BISULFITE CONTENT AND A RELATIVELY LOWER PH, RECOVERING SAID EXTRACT, REGENERATING AT LEAST A PORTION OF THE SODIUM BISULFITE CONTENT OF SAID EXTRACT TO SODIUM SULFITE BY TREATMENT IN A SINGLE REGENERATION STEP WITH A CALCIUM COMPOUND SELECTED FROM THE GROUP CONSISTING OF CALCIUM OXIDE AND
Claim 3
Dependent Claim
17 words
Process of claim 1 wherein said slurry has a pH of from about 8 to about 9.
Claim 4
Dependent Claim
17 words
Process of claim 1 wherein said slurry has a pH of from about 8 to about 8.5.
Claim 5
Dependent Claim
17 words
Process of claim 1 wherein said extracting solution has a pH of from about 6.2 to 6.7.
Claim 6
Dependent Claim
16 words
Process of claim 1 wherein said extract has a pH of about 5.9 to about 6.3.
Claim 7
Dependent Claim
52 words
process of claim 1 wherein the recovered extract is first blended with said regenerated aqueous solution and a portion of the blend is thereafter reacted with said calcium compound to regenerate the sodium bisulfite content while the remainder of the blend is recycled to the gas-liquid contactor as said circulating extracting solution.
Claim 8
Dependent Claim
40 words
Process of claim 1 wherein a sodium salt selected from the group consisting of sodium carbonate, sodium hydroxide, trona, nahcolite and sodium sesquicarbonate is added to said blended aqueous solution to make up sodium values removed with said calcium sulfite.
Claim 9
Dependent Claim
11 words
Process of claim 1 wherein said calcium compound is calcium hydroxide.
Claim 10
Dependent Claim
11 words
Process of claim 6 wherein said sodium salt is sodium carbonate.
Claim 11
Dependent Claim
11 words
Process of claim 6 wherein said sodium salt is sodium hydroxide.
Claim 12
Dependent Claim
10 words
Process of claim 6 wherein said sodium salt is trona.
Claim 13
Dependent Claim
24 words
Process of claim 1 wherein a portion of the recovered extract is removed directly to a regenerating zone and reacted with said calcium compound.
Claim 14
Dependent Claim
66 words
Process of claim 1 wherein the circulating extracting solution contains at least 20 weight percent total of dissolved sodium salts including sodium sulfate, and wherein the amount of sodium sulfate in the circulating extracting solution relative to sodium sulfate and sodium bisulfite is in a sulfate-to-sulfite plus bisulfite molar ratio greater than about 1 but less than the sodium sulfate saturation level in the extracting solution.
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) | 1978-10-06 | 1979-04-07 | 1979-10-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-10-06 | 1983-04-07 | 1983-10-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-10-06 | 1987-04-07 | 1987-10-07 | $7700.00 | Window Closed / Lapsed |