US3911081A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Catalytic oxidation of nitric oxide in molten salt
Assignee: Battelle Memorial Institute Inc
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Filing: 1972-06-28
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Granted: 1975-10-07
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Expires: 1992-06-28
Abstract
Abstract A catalytic oxidation process is described for oxidizing nitric oxide to a higher oxide of nitrogen such as nitrogen dioxide in which a gaseous steam containing oxygen and nitric oxide is contacted with a molten alkali-metal sulfate salt containing an oxidizing agent of an oxide of vanadium to catalytically oxidize the nitric oxide in the presence of oxygen. The gaseous stream containing the higher oxide of nitrogen is then contacted with an absorbent to remove the nitrogen oxide from the gaseous stream. Preferably the absorbent is an alkali-metal carbonate that is maintained in a molten state of between 300* and 500*C. that reacts with the nitrogen oxide to form an alkali-metal nitrate.
Inventors
- 👤 Roy F Maness
- 👤 Raymond H Moore
- 👤 Charles A Rohrmann
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 23:30
CPC Classifications
B; B01; B01D; B01D53/00; B01D53/34; B01D53/74; B01D53/86; B01D53/8621; B01D53/8625
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
59 words
A PROCESS FOR TREATING A GASEOUS STREAM ACONTAINING NITRIC OXIDE AND OXYGEN, COMPRISING THE STEP: CONTACTING THE GASEOUS STREAM WITH A MOLTON ALKALI-METAL SULFATE SOLUTION OF A TEMPERATURE BETWEEN 300* AND 500* C CONTAINING A CATALKYST OF VANADIUM PENTOXIDE TO CATALYTICALLY OXIDIZE THE NITRIC OXIDE T A HIGHER OXIDE OF NITROGEN, IN WHICH THE MOLTON ALKALI-METAL SULFATE SOLUTION COM-
Claim 2
Dependent Claim
59 words
A PROCESS FOR TREATING A GASEOUS STREAM ACONTAINING NITRIC OXIDE AND OXYGEN, COMPRISING THE STEP: CONTACTING THE GASEOUS STREAM WITH A MOLTON ALKALI-METAL SULFATE SOLUTION OF A TEMPERATURE BETWEEN 300* AND 500* C CONTAINING A CATALKYST OF VANADIUM PENTOXIDE TO CATALYTICALLY OXIDIZE THE NITRIC OXIDE T A HIGHER OXIDE OF NITROGEN, IN WHICH THE MOLTON ALKALI-METAL SULFATE SOLUTION COM-
Claim 3
Dependent Claim
22 words
A process as defined in claim 1 wherein the molten alkali-metal sulfate solution contains a mixture of alkali-metal sulfate and alkali-metal pyrosulfate.
Claim 4
Dependent Claim
24 words
The process as defined in claim 1 wherein the molten alkali-metal salt solution is maintained at a temperature between 400* C. and 460* C.
Claim 5
Dependent Claim
20 words
The process as defined in claim 1 wherein the alkali-metal is selected from a group consisting of sodium and potassium.
Claim 6
Dependent Claim
72 words
The process as defined in claim 1 further comprising the step of contacting the gaseous stream subsequently to the oxidation of the nitric oxide to a higher oxide of nitrogen with a molten absorbent of non-gaseous carbonate salt or a salt that forms a carbonate in the presence of carbon dioxide which reacts with the higher oxide of nitrogen to absorb the higher oxide of nitrogen and form a non-gaseous nitrate salt.
Claim 7
Dependent Claim
31 words
The process as defined in claim 5 wherein the molten absorbent is selected from a group consisting of potassium carbonate, sodium carbonate, potassium hydroxide, sodium hydroxide, calcium carbonate and calcium oxide.
Claim 8
Dependent Claim
26 words
The process as defined in claim 6 wherein the molten absorbent is maintained at a temperature above 250* C while in contact with the gaseous stream.
Claim 9
Dependent Claim
25 words
The process as defined in claim 5 wherein the non-gaseous salt is an alkali-metal carbonate selected from an alkali-metal group consisting of sodium and potassium.
Claim 10
Dependent Claim
23 words
The process as defined in claim 8 wherein the molten absorbent includes a molten solution of the alkali-metal carbonate dissolved in alkali-metal nitrate.
Claim 11
Dependent Claim
27 words
The process as defined in claim 8 further comprising the step of maintaining the alkali-metal carbonate salt content in the solution between 5 and 20 mole percent.
Claim 12
Dependent Claim
62 words
The process as defined in claim 8 wherein the gaseous stream is passed through a gas-liquid reactor and wherein the molten alkali-metal carbonate contacts the gaseous stream in said reactor and wherein the process further comprises the steps of continuously adding the alkali-metal carbonate salt to the reactor and continuously bleeding a portion of the molten alkali-metal carbonate-nitrate solution from the reactor.
Claim 13
Dependent Claim
28 words
The process as defined in claim 5 further comprising the step of contacting the alkali-metal nitrate salt with sulfuric acid to form nitric acid and regenerated alkali-metal sulfate.
Claim 14
Dependent Claim
36 words
The process as defined in claim 12 further comprising the steps of: separating the nitric acid and regenerated alkali-metal sulfate; and adding the regenerated alkali-metal sulfate to the molten alkali-metal sulfate solution defined in claim 1.
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) | 1978-10-06 | 1979-04-07 | 1979-10-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-10-06 | 1983-04-07 | 1983-10-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-10-06 | 1987-04-07 | 1987-10-07 | $7700.00 | Window Closed / Lapsed |