US3883638A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for removing sulfur dioxide and sulfur trioxide from waste gas and producing sulfur therefrom
Assignee: IFP Energies nouvelles
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Filing: 1973-03-15
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Granted: 1975-05-13
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Expires: 1993-03-15
Abstract
Abstract A waste gas containing SO2 and SO3 is washed with water and ammonia; the resulting solution of ammonium sulfites and sulfates is heated for converting the sulfites to SO2 and NH3, the sulfates are reacted with a reducing agent for producing additional SO2 and all the SO2 is reacted with H2S so as to obtain sulfur. A flow of inert gas is passed through the intermediately formed solution of neutral ammonium sulfate for converting it to ammonium hydrogen sulfate.
Inventors
- 👤 Philippe Renault
- 👤 Claude Dezael
- 👤 Andre Deschamps
- 👤 Sigismond Franckowiak
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 18:22
CPC Classifications
C; C01; C01B; C01B17/00; C01B17/02; C01B17/04; C01B17/05; B; B01; B01D; B01D53/00; B01D53/34; B01D53/46; B01D53/48; B01D53/50; B01D53/501
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
150 words
IN A PROCESS FOR PURIFYING A WASTE GAS CONTAINING SULFUR DIOXIDE AND SULFUR TRIOXIDE, WHEREIN THE WASTE GAS IS CONTACTED WITH AMMONIA AND WATER, SO AS TO OBTAIN AN AQUEOUS SOLUTION OF AMMONIUM SALTS, CONTAINING AMMONIUM SULFITES AND SULFATES, THIS SOLUTION IS HEATED UP TO A SUFFICIENT TEMPERATURE FOR CONVERTING THE AMMONIUM SULFITES TO SULFUR DIOXIDE AND AMMONIA, AT LEAST A PORTION OF SAID SULFUR DIOXIDE IS REACTED WITH HYDROGEN SULFIDE, SO AS TO OBTAIN SULFUR, AND THE AMMONIA IS RECYCLED TO THE WASTE GAS CONTACTING ZONE, THE IMPROVEMENT COMPRISING THE ADDITIONAL STEP OF FURTHER HEATING THE SOLUTION TO 160*-300*C., THE SULFITES OF WHICH HAVE BEEN CONVERTED, SO AS TO MELT THE AMMONIUM SULFATES, TREATING IT WITH AT LEAST A PORTION OF THE WASTE GAS BEFORE CONTACT OF SAID PORTION WITH AMMONIA AND WATER, SAID PORTION BEING THEREAFTER CONTACTED WITH SAID AMMONIA AND WATER, SO AS TO TRANSFORM THE AMMO-
Claim 2
Dependent Claim
150 words
IN A PROCESS FOR PURIFYING A WASTE GAS CONTAINING SULFUR DIOXIDE AND SULFUR TRIOXIDE, WHEREIN THE WASTE GAS IS CONTACTED WITH AMMONIA AND WATER, SO AS TO OBTAIN AN AQUEOUS SOLUTION OF AMMONIUM SALTS, CONTAINING AMMONIUM SULFITES AND SULFATES, THIS SOLUTION IS HEATED UP TO A SUFFICIENT TEMPERATURE FOR CONVERTING THE AMMONIUM SULFITES TO SULFUR DIOXIDE AND AMMONIA, AT LEAST A PORTION OF SAID SULFUR DIOXIDE IS REACTED WITH HYDROGEN SULFIDE, SO AS TO OBTAIN SULFUR, AND THE AMMONIA IS RECYCLED TO THE WASTE GAS CONTACTING ZONE, THE IMPROVEMENT COMPRISING THE ADDITIONAL STEP OF FURTHER HEATING THE SOLUTION TO 160*-300*C., THE SULFITES OF WHICH HAVE BEEN CONVERTED, SO AS TO MELT THE AMMONIUM SULFATES, TREATING IT WITH AT LEAST A PORTION OF THE WASTE GAS BEFORE CONTACT OF SAID PORTION WITH AMMONIA AND WATER, SAID PORTION BEING THEREAFTER CONTACTED WITH SAID AMMONIA AND WATER, SO AS TO TRANSFORM THE AMMO-
Claim 3
Dependent Claim
30 words
A process according to claim 1, wherein the aqueous solution containing the ammonium salts is heated up to a a first temperature in the range of from 120* to 160*C.
Claim 4
Dependent Claim
39 words
A process according to claim 1, wherein the aqueous solution containing the ammonium salts, after removal of the major part of the sulfites therefrom, is heated up to a second temperature in the range of from 180* to 250*C.
Claim 5
Dependent Claim
27 words
A process according to claim 1, wherein the reducing agent reacted with the ammonium hydrogen sulfate is hydrogen sulfide, sulfur, carbon, formic acid, a hydrocarbon or hydrogen.
Claim 6
Dependent Claim
42 words
A process according to claim 1, wherein the ammonium neutral sulfate, obtained as a by-product of the reaction of the ammonium hydrogen sulfate with the reducing agent, is treated again with a gas flow so as to form ammonium hydrogen sulfate again.
References Cited (Backward Citations)
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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) | 1978-05-12 | 1978-11-11 | 1979-05-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-05-12 | 1982-11-11 | 1983-05-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-05-12 | 1986-11-11 | 1987-05-13 | $7700.00 | Window Closed / Lapsed |