Claims
- 1. In a continuous process comprising oxidizing hydrogen sulfide absorbed in an aqueous alkaline scrubbing agent having a pH of 8-9 and prepared by admixing in water a vanadate oxidizing agent, anthraquinonedisulfonic acid and sodium carbonate, the weight proportion of the vanadium to the anthraquinonedisulfonic acid being about 1:2, the hydrogen sulfide being thereby oxidized principally to elementary sulfur; regenerating the scrubbing agent in an oxidizer to reoxidize reduced vanadate with an oxygen containing gas; and recycling the resultant scrubbing agent to the scrubbing step, said process being susceptible to the formation of thiosulfate, the improvement consisting essentially of providing a sufficient concentration of a source of thiocyanate in the scrubbing agent to prevent any build-up of thiosulfate after at least 1,000 hours of operation, which build-up would otherwise occur in the absence of the addition of said source of thiocyanate.
- 2. A process according to claim 1, wherein the source of thiocyanate is added in a concentration of 0.06 to 0.5 mol thiocyanate per liter.
- 3. A process according to claim 1, wherein the source of thiocyanate is added in a concentration of 0.2 to 0.4 mol thiocyanate per liter.
- 4. A process according to claim 1, wherein said aqueous alkaline scrubbing agent consists essentially of 1.5 g/liter of vanadium, 3 g/liter of anthraquinonedisulfonic acid in salt form, and 30 g/liter of sodium thiocyanate.
- 5. In a continuous process comprising oxidizing hydrogen sulfide absorbed in an aqueous alkaline scrubbing agent containing a vanadate oxidizing agent and a promoter consisting essentially of an amine, the hydrogen sulfide being thereby oxidized principally to elemental sulfur; regenerating the scrubbing agent in an oxidizer to reoxidize reduced vanadate with an oxygen containing gas; and recycling the resultant regenerated scrubbing agent to the scrubbing step, said process being susceptible to the formation of thiosulfate, the improvement comprising providing a sufficient concentration of a source of thiocyanate in the scrubbing agent to prevent any build-up of thiosulfate after at least 500 hours of operation.
- 6. A process according to claim 5, wherein said aqueous alkaline scrubbing agent consists essentially of the vanadate, the amine, and the source of thiocyanate.
- 7. A process according to claim 6, wherein said aqueous alkaline scrubbing agent contains sodium carbonate.
- 8. A process according to claim 6, wherein said amine is an alkanol amine.
- 9. A process according to claim 8, wherein said alkanol amine is methyldiethanolamine.
- 10. A process according to claim 7, wherein said amine is an alkanol amine.
- 11. A process according to claim 10, wherein said alkanol amine is methyldiethanolamine.
- 12. A process according to claim 5, wherein said amine is an alkanol amine.
- 13. A process according to claim 5, wherein said alkanol amine is methyldiethanolamine.
Priority Claims (1)
Number |
Date |
Country |
Kind |
3219762 |
May 1982 |
DEX |
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CROSS-REFERENCE TO RELATED APPLICATION
This application is a continuation-in-part of application Ser. No. 406,805, filed Aug. 10, 1982, now abandoned.
US Referenced Citations (3)
Number |
Name |
Date |
Kind |
3972989 |
Fenton et al. |
Aug 1976 |
|
4017594 |
Fenton et al. |
Apr 1977 |
|
4325936 |
Gowdy et al. |
Apr 1982 |
|
Foreign Referenced Citations (1)
Number |
Date |
Country |
1488659 |
Oct 1977 |
GBX |
Non-Patent Literature Citations (1)
Entry |
Kohl et al., "Gas Purification", 3rd Ed., Gulf Publishing Co., Houston, pp. 476-487. |
Continuation in Parts (1)
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Number |
Date |
Country |
Parent |
406805 |
Aug 1982 |
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