US3635820A
Expired / Lapsed
US
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Treating a water stream containing a water-soluble sulfite compound
Assignee: Universal Oil Products Co
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Filing: 1970-08-31
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Granted: 1972-01-18
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Expires: 1990-08-31
Abstract
Abstract A water stream containing a water-soluble sulfite compound is treated in order to reduce its total sulfur content while minimizing the formation of sulfate byproducts by the steps of: (a) converting the sulfite compound contained in the water stream to the corresponding thiosulfate compound; (b) catalytically reacting the resulting thiosulfate compound with hydrogen at reduction conditions selected to produce the corresponding sulfide compound; and thereafter (c) stripping hydrogen sulfide from an effluent stream from step (b) to form a substantially sulfate-free treated water stream which is substantially reduced in total sulfur content relative to the input water stream. Principal utility of this treatment procedure is associated with the regeneration of a sulfite-containing absorbent stream which is commonly produced by contacting a flue gas stream containing sulfur dioxide with a suitable aqueous absorbent stream containing an alkaline reagent.
Inventors
- 👤 Peter Urban
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 06:34
CPC Classifications
B; B01; B01D; B01D53/00; B01D53/34; B01D53/46; B01D53/48; B01D53/50; B01D53/501; B01D53/52; C; C01; C01B; C01B17/00; C01B17/16; C01B17/164; C02; C02F; C02F1/00; C02F1/70; C10; C10K; C10K1/00; C10K1/08; C10K1/10; C10K1/12; C10K1/122
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
39 words
A method as defined in claim 1 wherein the reaction conditions utilized in step (a) include a temperature of about 20* to about 150* C., and a pressure Sufficient to maintain the input water stream in the liquid phase.
Claim 2
Dependent Claim
41 words
A method as defined in claim 1 wherein the reduction conditions utilized in step (b) include a temperature of about 125* to about 350* C. and a pressure sufficient to maintain the effluent stream from step (a) in the liquid phase.
Claim 3
Dependent Claim
15 words
A method as defined in claim 1 wherein the water-soluble sulfite compound is ammonium sulfite.
Claim 4
Dependent Claim
17 words
A method as defined in claim 1 wherein the water-soluble sulfite compound is an alkali metal sulfite.
Claim 5
Dependent Claim
15 words
A method as defined in claim 5 wherein said alkali metal sulfite is sodium sulfite.
Claim 6
Independent Claim
17 words
A method as defined in claim wherein the water-soluble sulfite compound is an alkaline earth metal sulfite.
Claim 7
Dependent Claim
15 words
A method as defined in claim 7 wherein the alkaline earth sulfite is magnesium sulfite.
Claim 8
Dependent Claim
33 words
A method as defined in claim 1 wherein the amount of hydrogen charged to step (b) is sufficient to provide a mole ratio of hydrogen to thiosulfate passed thereto of at least 4:1.
Claim 9
Dependent Claim
18 words
A method as defined in claim 1 wherein the reducing agent utilized in step (a) is hydrogen sulfide.
Claim 10
Dependent Claim
35 words
A method as defined in claim 10 wherein at least a portion of the hydrogen sulfide utilized in step (a) is obtained by passing thereto a portion of the hydrogen sulfide stripped in step (c).
Claim 11
Dependent Claim
39 words
A method as defined in claim 1 wherein the reducing agent utilized in step (a) is finely divided sulfur which is used in an amount at least sufficient to provide a mole ratio of sulfur to sulfite of 1:1.
Claim 12
Dependent Claim
39 words
A method as defined in claim 1 wherein the reducing agent utilized in step (a) is a polysulfide compound which is used in an amount at least sufficient to provide a mole ratio of polysulfide to sulfite of 1:6.
Claim 13
Dependent Claim
40 words
A method as defined in claim 1 wherein the reducing agent utilized in step (a) is a water-soluble sulfide compound which is used in an amount at least sufficient to provide a mole ratio of sulfide to sulfite of 1:2.
Claim 14
Dependent Claim
25 words
A method as defined in claim 1 wherein the input water stream contains about 0.1 to about 25 wt. percent of the water-soluble sulfite compound.
Claim 15
Dependent Claim
51 words
A method as defined in claim 1 wherein step (b) comprises contacting the effluent stream from step (a) and hydrogen with a reduction catalyst, comprising an iron group metallic component combined with a carrier material, at reduction conditions selected to form a substantially thiosulfate-free aqueous effluent stream containing a sulfide compound.
Claim 16
Dependent Claim
21 words
A method as defined in claim 16 wherein said reduction catalyst comprises cobalt sulfide combined with an activated carbon carrier material.
Claim 17
Dependent Claim
22 words
A method as defined in claim 16 wherein said reduction catalyst comprises cobalt sulfide combined with a refractory inorganic oxide carrier material.
Claim 18
Independent Claim
166 words
A method for treating an input water stream containing ammonium sulfite in order to reduce its total sulfur content while minimizing the formation of ammonium sulfate, said method comprising the steps of: a. reacting the input water stream with hydrogen sulfide at reaction conditions selected to form an effluent stream containing ammonium thiosulfate; b. contacting the effluent stream from step (a) and hydrogen with a reduction catalyst comprising cobalt sulfide combined with a carrier material, at reduction conditions selected to form a substantially thiosulfate-free aqueous effluent stream containing ammonium hydrosulfide; c. stripping hydrogen sulfide from the aqueous effluent stream produced in step (b) to form a hydrogen sulfide-containing overhead gas stream and a treated water stream which is substantially reduced in total sulfur content relative to the input water stream and is substantially free of ammonium sulfate; and d. passing a portion of the overhead stream formed in step (c) to step (a) in order to supply at least a portion of said hydrogen sulfide thereto.
Claim 19
Dependent Claim
35 words
A method as defined in claim 18 wherein hydrogen is charged to step (b) in an amount corresponding to about 4 to about 100 moles of hydrogen per mole of the thiosulfate compound passed thereto.
Claim 20
Dependent Claim
41 words
A method as defined in claim 18 wherein the reduction conditions utilized in step (b) include a temperature of about 125* to about 350* C. and a pressure sufficient to maintain the effluent stream from step (a) in the liquid phase.
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) | 1975-01-17 | 1975-07-19 | 1976-01-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-01-17 | 1979-07-19 | 1980-01-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-01-17 | 1983-07-19 | 1984-01-18 | $7700.00 | Window Closed / Lapsed |