US3635657A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for the removal of nitric oxide from industrial gases
Assignee: MONLECATINI EDISON SpA
•
Filing: 1969-08-29
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Granted: 1972-01-18
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Expires: 1989-08-29
Abstract
Abstract Nitric oxide is removed from industrial gases, more particularly from gases formed in the cracking of hydrocarbons, by absorption in an aqueous solution containing at least one ferrous salt, at least one ammonia salt and free ammonia, under conditions such that the nitric oxide, which is usually present in the cracking gases in an amount of 50 to 200 p.p.m., is either totally removed or reduced to less than 0.5 to 1.0 p.p.m., in a single stage or step.
Inventors
- 👤 Giancarlo Bressan
- 👤 Salvatore Gafa
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 05:47
CPC Classifications
B; B01; B01D; B01D53/00; B01D53/34; B01D53/46; B01D53/54; B01D53/56; C; C10; C10K; C10K1/00; C10K1/08; C10K1/10; C10K1/12; C10K1/124; C10K1/125
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
37 words
The process according to claim 1, characterized in that the gas is washed at a temperature of the washing solution of from 10* to 50* C., and with a contact time of from 10 to 50 seconds.
Claim 2
Dependent Claim
26 words
The process according to claim 1, characterized in that the gas from which the NO is to be absorbed is washed countercurrently with the aqueous solution.
Claim 3
Dependent Claim
30 words
The process according to claim 1, characterized in that the ferrous salt is selected from the group consisting of the hydroxide, chloride, nitrate, carbonate, sulfate, sulfite, formate, acetate and oxalate.
Claim 4
Dependent Claim
16 words
The process according to claim 3, further characterized in that the ferrous salt is ferrous chloride.
Claim 5
Dependent Claim
16 words
The process according to claim 3, further characterized in that the ferrous salt is ferrous sulfate.
Claim 6
Dependent Claim
28 words
The process according to claim 1, characterized in that the ammonium salt is selected from the group consisting of the sulfate, sulfite, chloride, nitrate, carbonate, carbamate and bicarbonate.
Claim 7
Dependent Claim
16 words
The process according to claim 7, further characterized in that the ammonium salt is ammonium chloride.
Claim 8
Dependent Claim
16 words
The process according to claim 7, further characterized in that the ammonium salt is ammonium carbonate.
Claim 9
Dependent Claim
16 words
The process according to claim 7, further characterized in that the ammonium salt is ammonium carbamate.
Claim 10
Dependent Claim
16 words
The process according to claim 7, further characterized in that the ammonium salt is ammonium bicarbonate.
Claim 11
Dependent Claim
22 words
The process according to claim 1, further characterized in that the aqueous washing solution contains from 0.4 to 2.0 M/l. of ammonia.
Claim 12
Dependent Claim
27 words
The process according to claim 1, characterized in that washing of the gas with the aqueous washing solution is carried out in the presence of metallic iron.
References Cited (Backward Citations)
US3382033A
Cited
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 |