US4070305A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for regenerating catalyst
Assignee: Sumitomo Seika Chemicals Co Ltd
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Filing: 1976-03-01
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Granted: 1978-01-24
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Expires: 1996-03-01
Abstract
Abstract Catalyst for removing nitrogen oxides, whose activity is lowered by poisoning with sulfur oxides, is contacted with an ammonia gas at a temperature of 200° to 500° C, whereby the sulfur oxides are liberated from the catalyst, and the catalyst is regenerated. Concentration of the ammonia gas to be used in the regeneration treatment must be at least 1% by volume and preferably 5 to 50% by volume of ammonia is used in a mixture with other inert diluting gas. The regenerated catalyst is given an activity as high as that before the poisoning without bringing about any damage and cracking to the catalyst.
Inventors
- 👤 Shigeji Obayashi
- 👤 Kanji Ueda
- 👤 Haruhiko Iwatsubo
- 👤 Thoru Okabe
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 20:44
CPC Classifications
B; B01; B01D; B01D53/00; B01D53/34; B01D53/74; B01D53/86; B01D53/8621; B01D53/8625; B01D53/8628; B01J; B01J23/00; B01J23/90; B01J23/92; B01J23/94; Y; Y10; Y10S; Y10S502/00; Y10S502/515; Y10S502/517
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
117 words
A process for regenerating a catalyst used for removing nitrogen oxides from flue gas by catalytic reduction with ammonia and wherein said catalyst is an oxide of a metal selected from the group consisting of copper, iron, chromium, vanadium, and mixtures thereof, and said catalyst is poisoned by the formation of sulfates with sulfur oxides contained in said flue gas, which process comprises contacting said poisoned catalyst at a temperature of 350° to 500° C with a gaseous mixture consisting essentially of at least 1% by volume of ammonia and a substantially inert gas and for a time sufficient for regenerating said catalyst to liberate the sulfur oxides thereby from said catalyst, whereby said catalyst is regenerated.
Claim 2
Dependent Claim
117 words
A process for regenerating a catalyst used for removing nitrogen oxides from flue gas by catalytic reduction with ammonia and wherein said catalyst is an oxide of a metal selected from the group consisting of copper, iron, chromium, vanadium, and mixtures thereof, and said catalyst is poisoned by the formation of sulfates with sulfur oxides contained in said flue gas, which process comprises contacting said poisoned catalyst at a temperature of 350° to 500° C with a gaseous mixture consisting essentially of at least 1% by volume of ammonia and a substantially inert gas and for a time sufficient for regenerating said catalyst to liberate the sulfur oxides thereby from said catalyst, whereby said catalyst is regenerated.
Claim 3
Dependent Claim
25 words
The process of claim 1 wherein said inert gas is selected from the group consisting of nitrogen, helium, argon, cabon dioxide, steam, and mixtures thereof.
Claim 4
Dependent Claim
18 words
The process of claim 1 wherein said gas consists of 10% NH 3 and 90% N 2 .
Claim 5
Dependent Claim
11 words
The process of claim 1 wherein said gas is 100% ammonia.
Claim 6
Dependent Claim
23 words
The method of claim 1 wherein said gas consists of 5% NH 3 , 94% N 2 , and 1% O 2 .
Claim 7
Dependent Claim
18 words
The method of claim 1 wherein said gas consists of 15% NH 3 and 85% N 2 .
Claim 8
Dependent Claim
18 words
The method of claim 1 wherein said gas consists of 30% NH 3 and 70% N 2 .
Claim 9
Dependent Claim
24 words
The method of claim 2 wherein said gas also contains oxygen or sulfur dioxide in small amounts insufficient to significantly increase the ammonia consumption.
Claim 10
Dependent Claim
15 words
The method of claim 1 wherein said catalyst is supported on an inorganic porous material.
Claim 11
Dependent Claim
14 words
The method of claim 9 wherein said inorganic porous material is alumina or silica.
Claim 12
Dependent Claim
14 words
The method of claim 1 wherein the catalyst is supported on an alumina carrier.
Claim 13
Dependent Claim
32 words
The method of claim 1 wherein said catalyst comprises iron oxide and at least one other oxide of a metal selected from the group consisting of copper, chromium, vanadium, and mixtures thereof.
Claim 14
Dependent Claim
16 words
The method of claim 1 wherein said gas contains 5 to 50% by volume of ammonia.
Claim 15
Dependent Claim
11 words
The method of claim 1 wherein said catalyst comprises iron oxide.
Claim 16
Dependent Claim
13 words
The method of claim 1 wherein said catalyst comprises an oxide of vanadium.
Claim 17
Dependent Claim
15 words
The method of claim 1 wherein said catalyst comprises oxides of copper and of chromium.
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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) | 1981-01-23 | 1981-07-25 | 1982-01-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-01-23 | 1985-07-25 | 1986-01-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-01-23 | 1989-07-25 | 1990-01-24 | $7700.00 | Window Closed / Lapsed |