US4043939A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Reactivation of catalysts useful for nitrogen oxide removal
Assignee: Kurashiki Spinning Co Ltd
•
Filing: 1975-10-10
•
Granted: 1977-08-23
•
Expires: 1995-10-10
Abstract
Abstract Catalysts inactivated in the course of removing nitrogen oxides in the presence of ammonia by poisons present in exhaust gas can be reactivated for repeated reuses by calcination in the atmosphere at an elevated temperature, e.g., from about 700° C to 1,200° C.
Inventors
- 👤 Shigeaki Kasaoka
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 07:35
CPC Classifications
B; B01; B01J; B01J23/00; B01J23/90; B01J23/96; B01D; B01D53/00; B01D53/34; B01D53/74; B01D53/86; B01D53/8621; B01D53/8625; B01D53/8628; B01J23/92; B01J23/94
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
117 words
A method of regenerating a catalyst which removes nitrogen oxides from exhaust gas in the presence of ammonia, which catalyst comprises copper, iron, cobalt, chromium, nickel, manganese, titanium, vanadium, molybedenum, silver, platinum, rhodium or palladium supported on an alumina, silica-alumina, magnesia-alumina, titania-alumina, calcium oxide alumina, chromium oxide-alumina, or chromium oxide alumina carrier, which catalyst has been employed to remove nitrogen oxides from exhaust gas in the presence of ammonia, and which is inactivated by the presence of sulfur oxides in the exhaust gas which method comprises calcining said catalyst in substantially the atmosphere at a temperature in the range of from about 700° to 1200° C thereby restoring the initial nitrogen oxide removing activity of said catalyst.
Claim 2
Independent Claim
117 words
A method of regenerating a catalyst which removes nitrogen oxides from exhaust gas in the presence of ammonia, which catalyst comprises copper, iron, cobalt, chromium, nickel, manganese, titanium, vanadium, molybedenum, silver, platinum, rhodium or palladium supported on an alumina, silica-alumina, magnesia-alumina, titania-alumina, calcium oxide alumina, chromium oxide-alumina, or chromium oxide alumina carrier, which catalyst has been employed to remove nitrogen oxides from exhaust gas in the presence of ammonia, and which is inactivated by the presence of sulfur oxides in the exhaust gas which method comprises calcining said catalyst in substantially the atmosphere at a temperature in the range of from about 700° to 1200° C thereby restoring the initial nitrogen oxide removing activity of said catalyst.
Claim 3
Dependent Claim
19 words
A method, in in claim 1, wherein the temperature is in the range of about 800° to 900° C.
Claim 4
Dependent Claim
12 words
A method, as in claim 1, of regenerating a catalyst comprising copper.
Claim 5
Dependent Claim
19 words
A method, as in claim 3, wherein the temperature is in the range of about 800° to 900° C.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1980-08-22 | 1981-02-21 | 1981-08-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-08-22 | 1985-02-21 | 1985-08-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-08-22 | 1989-02-21 | 1989-08-23 | $7700.00 | Window Closed / Lapsed |