US3565575A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Removal of nitrogen oxides from a gas stream
Assignee: Chemical Construction Corp
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Filing: 1968-05-22
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Granted: 1971-02-23
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Expires: 1988-05-22
Abstract
Abstract A GAS STREAM CONTAINING NITROGEN OXIDES, SUCH AS THE TAIL GAS FROM A NITRIC ACID PLANT, IS SRUBBED WITH AN AQUEOUS UREA SOLUTION. THE NITROGEN OXIDES DISSOLVE IN THE SOLUTION TO FORM NITROUS ACID, WHICH REACTS WITH THE UREA TO FORM NITROGEN, CARBON DIOXIDE AND WATER. THE RESULTING SCRUBBED GAS STREAM IS OF REDUCED NITROGEN OXIDES CONTENT AND, IN THE CASE OF NITRIC ACID PLANT TAIL GAS, MAY BE SAFETLY DISCHARGED TO THE ATMOSPHERE WITHOUT CAUSING AIR POLLUTION.
Inventors
- 👤 Abe Warshaw
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 14:19
CPC Classifications
B; B01; B01D; B01D53/00; B01D53/34; B01D53/46; B01D53/54; B01D53/56
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-02-22 | 1974-08-24 | 1975-02-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-02-22 | 1978-08-24 | 1979-02-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-02-22 | 1982-08-24 | 1983-02-23 | $7700.00 | Window Closed / Lapsed |