US4079118A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for removing nitrogen oxides using ferricion-EDTA complex solutions
Assignee: JNC Engineering Co Ltd
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Filing: 1974-12-27
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Granted: 1978-03-14
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Expires: 1994-12-27
Abstract
Abstract Industrial exhaust gas containing nitrogen oxides is treated with an aqueous solution of an iron chelate complex salt which contains essentially a sulfite salt at the time of treatment whereby nitrogen oxides which have been difficult to catch can be absorbed with a high absorbing rate even when the concentration of nitrogen oxides is low in the exhaust gas or sulfur dioxide is included in the gas, and simultaneous desulfurizing can be attained in this case. Said aqueous solution has a large absorbing capacity and may contain an ion or ions of alkali metal, alkali earth metal or ammonium.
Inventors
- 👤 Tokio Gorai
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 11:03
CPC Classifications
B; B01; B01D; B01D53/00; B01D53/34; B01D53/46; B01D53/54; B01D53/56
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
93 words
A method for removing nitrogen monoxide from gases containing the same which consists essentially of contacting said gases with an aqueous solution consisting essentially of a ferric ion - ethylenediaminetetraacetic acid complex salt and a sulfite salt selected from the group consisting of ammonium sulfite, alkali metal sulfites and alkaline earth metal sulfites, and recovering a gas containing a reduced content of nitrogen monoxide, the concentration of said complex salt in the aqueous solution being 0.1 - 10% and the concentration of the sulfite salt in the aqueous solution is 2 - 30%.
Claim 2
Independent Claim
93 words
A method for removing nitrogen monoxide from gases containing the same which consists essentially of contacting said gases with an aqueous solution consisting essentially of a ferric ion - ethylenediaminetetraacetic acid complex salt and a sulfite salt selected from the group consisting of ammonium sulfite, alkali metal sulfites and alkaline earth metal sulfites, and recovering a gas containing a reduced content of nitrogen monoxide, the concentration of said complex salt in the aqueous solution being 0.1 - 10% and the concentration of the sulfite salt in the aqueous solution is 2 - 30%.
Claim 3
Dependent Claim
24 words
A method according to claim 1 wherein said sulfite salt is selected from the group consisting of ammonium sulfite sodium sulfite and calcium sulfite.
Claim 4
Dependent Claim
21 words
A method according to claim 1 wherein the concentration of said complex salt in the aqueous solution is 0.2 - 4%.
Claim 5
Dependent Claim
21 words
A method according to claim 1 wherein the concentration of the sulfite salt in the aqueous solution is 5 - 25%.
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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) | 1981-03-13 | 1981-09-12 | 1982-03-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-03-13 | 1985-09-12 | 1986-03-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-03-13 | 1989-09-12 | 1990-03-14 | $7700.00 | Window Closed / Lapsed |