US3932584A
Expired / Lapsed
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Method for purifying hydrogen sulfide-containing gas
Assignee: Asahi Kasei Corp
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Filing: 1974-01-25
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Granted: 1976-01-13
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Expires: 1994-01-25
Abstract
Abstract Hydrogen sulfide-containing waste gases whose complete treatment is indispensable from the viewpoint of environmental pollution problem, are purified in two steps consisting of a first step in which the gases are absorbed in an aqueous solution of sodium hydroxide or/and sodium sulfide, and a second step in which sulfuric acid and sulfur dioxide gas are simultaneously introduced into the resulting solution after absorption to deposit sulfur. Further, for recovery of the resulting sulfur, a particular apparatus is provided.
Inventors
- 👤 Tokuzo Asakusa
- 👤 Taketoshi Honma
- 👤 Isao Hirashita
- 👤 Koichi Yasui
- 👤 Yoshio Nishi
- 👤 Koichi Murayama
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 01:33
CPC Classifications
C; C01; C01B; C01B17/00; C01B17/02; C01B17/04; C01B17/05; B; B01; B01D; B01D53/00; B01D53/34; B01D53/46; B01D53/48; B01D53/52; B01D53/523
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
74 words
A method for purifying hydrogen sulfide-containing gas which comprises a first step of absorbing a hydrogen sulfide-containing gas in an aqueous solution of sodium hydroxide and/or sodium sulfide to obtain a solution containing sodium hydrosulfide, and a second step of introducing sulfuric acid and sulfur dioxide gas simultaneously into said aqueous solution after absorption while maintaining a reaction temperature of 5°-70°C and a pH of 1-6 to form sodium sulfate and to deposit sulfur.
Claim 2
Independent Claim
74 words
A method for purifying hydrogen sulfide-containing gas which comprises a first step of absorbing a hydrogen sulfide-containing gas in an aqueous solution of sodium hydroxide and/or sodium sulfide to obtain a solution containing sodium hydrosulfide, and a second step of introducing sulfuric acid and sulfur dioxide gas simultaneously into said aqueous solution after absorption while maintaining a reaction temperature of 5°-70°C and a pH of 1-6 to form sodium sulfate and to deposit sulfur.
Claim 3
Dependent Claim
29 words
A method according to claim 1 wherein said hydrogen sulfide-containing gas is a waste gas which is generated at the time of the production of viscose rayon or cellophane.
Claim 4
Dependent Claim
42 words
A method according to claim 1 wherein the concentration of said aqueous solution of sodium hydroxide and/or sodium sulfide to be used in the first step is 0.02-9 mols of sodium hydroxide and/or sodium sulfide per 1 L of said aqueous solution.
Claim 5
Dependent Claim
23 words
A method according to claim 1 wherein the linear velocity for introducing hydrogen sulfide-containing waste gas into said aqueous solution is 0.1-7 m/sec.
Claim 6
Dependent Claim
19 words
A method according to claim 1 wherein the liquid: gas ratio in the first step is 1/100-1/5000 by volume.
Claim 7
Dependent Claim
41 words
A method according to claim 1 wherein the concentration of sulfuric acid to be used in the second step is 1-300 g/L, and the concentration of sulfur dioxide gas to be introduced in the second step is 0.15-100 % by volume.
Claim 8
Dependent Claim
64 words
A method according to claim 1 wherein the concentration of the aqueous solution of sodium hydroxide or/and sodium sulfide is 1-5 mols of sodium hydroxide or/and sodium sulfide per 1 L of said aqueous solution; the concentration of sulfuric acid is 100-150 g/L; and in the second step, the reaction temperature is 30°-50°C, the reaction time is 30-90 minutes and the pH is 1-3.
Claim 9
Dependent Claim
31 words
The method of claim 1 which includes the further step of burning said deposited sulfur to form sulfur dioxide and returning said sulfur dioxide to the second step of the process.
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) | 1979-01-12 | 1979-07-14 | 1980-01-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-01-12 | 1983-07-14 | 1984-01-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-01-12 | 1987-07-14 | 1988-01-13 | $7700.00 | Window Closed / Lapsed |