US3985529A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for the production of liquid sulphur dioxide
Assignee: Boliden AB
•
Filing: 1974-10-07
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Granted: 1976-10-12
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Expires: 1994-10-07
Abstract
Abstract The method of recovering liquid sulphur dioxide from gases containing sulphur dioxide by washing with water in an absorption plant and then stripping off absorbed sulphur dioxide at subatmospheric pressure. Water is removed from the stripped gasesby cooling and drying and sulphur dioxide is removed by condensation. The whole system is kept at a subatmospheric pressure by pumping off residual gases after the sulphur dioxide condensation.
Inventors
- 👤 Stig Arvid Petersson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 19:54
CPC Classifications
C; C01; C01B; C01B17/00; C01B17/48; C01B17/50; C01B17/60; Y; Y10; Y10S; Y10S62/00; Y10S62/922
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
142 words
The method of recovering liquid sulphur dioxide from combustion gases containing sulphur dioxide comprising washing the gas with water in an absorption plant, so that the sulphur dioxide is absorbed by the washing water, introducing steam and said SO 2 absorbed in water into a stripping column maintained at a first pressure below atmospheric pressure and at a temperature between 15° and 98° C. whereby absorbed sulphur dioxide which contains water is stripped, cooling the steam treated watercontaining sulphur dioxide gas which is moist at a second pressure below atmospheric pressure so that the water condenses, further drying the gas by means of sulfuric acid, and liquefying the sulphur dioxide by condensing in a heat exchanger at below atmospheric pressure to further dry said gas, said first and second pressures being controlled by pumping off the residual gases after sulphur dioxide condensation.
Claim 2
Independent Claim
142 words
The method of recovering liquid sulphur dioxide from combustion gases containing sulphur dioxide comprising washing the gas with water in an absorption plant, so that the sulphur dioxide is absorbed by the washing water, introducing steam and said SO 2 absorbed in water into a stripping column maintained at a first pressure below atmospheric pressure and at a temperature between 15° and 98° C. whereby absorbed sulphur dioxide which contains water is stripped, cooling the steam treated watercontaining sulphur dioxide gas which is moist at a second pressure below atmospheric pressure so that the water condenses, further drying the gas by means of sulfuric acid, and liquefying the sulphur dioxide by condensing in a heat exchanger at below atmospheric pressure to further dry said gas, said first and second pressures being controlled by pumping off the residual gases after sulphur dioxide condensation.
Claim 3
Dependent Claim
17 words
The method in accordance with claim 1, wherein the condensed water is returned to the stripping column.
Claim 4
Dependent Claim
25 words
The method in accordance with claim 1, wherein the moist gas is cooled in a heat exchanger to a temperature between 0° and 10° C.
Claim 5
Dependent Claim
26 words
The method in accordance with claim 1, wherein the heat is exchanged between the out-going water from the stripping column and in-going water containing sulphur dioxide.
Claim 6
Dependent Claim
29 words
The method in accordance with claim 1, wherein an auxiliary pump is used to increase the pressure after drying with sulphuric acid but before the condensation of sulphur dioxide.
Claim 7
Dependent Claim
23 words
The method in accordance with claim 1, wherein the stripping takes place at a temperature of 30° to 70° C, preferably 40°-50° C.
Claim 8
Dependent Claim
17 words
The method in accordance with claim 1, wherein the residual gases are returned to the absorption tower.
Claim 9
Dependent Claim
18 words
The method in accordance with claim 1, wherein the further drying is effected by means of sulphuric acid.
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) | 1979-10-12 | 1980-04-12 | 1980-10-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-10-12 | 1984-04-12 | 1984-10-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-10-12 | 1988-04-12 | 1988-10-12 | $7700.00 | Window Closed / Lapsed |