Patent US4199555A successfully refreshed from Google Patents.
US4199555A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Catalyst for reducing nitrogen oxides
Assignee: Tonen General Sekiyu KK
•
Filing: 1978-08-23
•
Granted: 1980-04-22
•
Expires: 1998-08-23
Abstract
Abstract Nitrogen oxides are removed from gaseous mixtures comprising the same by contacting with a catalyst comprising a base metal component carried on a silica-alumina base in the presence of ammonia.
Inventors
- 👤 Takuji Itoh
- 👤 Satoshi Sakurada
- 👤 Nobuaki Tagaya
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 19:26
CPC Classifications
B; B01; B01D; B01D53/00; B01D53/34; B01D53/74; B01D53/86; B01D53/8621; B01D53/8625; B01D53/8628
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
160 words
A process for the removal of nitrogen oxides from an exhaust gas containing from 0.001 to 0.005% nitrogen oxides, from 0.01 to 0.3% sulfur oxides and from 3 to 10% oxygen which comprises contacting said exhaust gas with ammonia at a temperature varying from 200° to 500° C. with a catalyst comprising a metal component contained on a silica-alumina or a silica-alumina-containing carrier which contains 5 to 50% by weight of silica and which possesses the following properties: (1) a specific surface area of more than about 300 m 2 per gram; (2) a volume of pores having a diameter ranging from 0 to 600 Angstroms less than about 80% of the total volume of pores; (3) a volume of pores having a diameter ranging from 150 to 600 Angstroms more than about 30% of the volume of pores having a diameter ranging from 0 to 600 Angstroms; and (4) a bulk density less than about 0.5 grams per milliliter.
Claim 2
Dependent Claim
160 words
A process for the removal of nitrogen oxides from an exhaust gas containing from 0.001 to 0.005% nitrogen oxides, from 0.01 to 0.3% sulfur oxides and from 3 to 10% oxygen which comprises contacting said exhaust gas with ammonia at a temperature varying from 200° to 500° C. with a catalyst comprising a metal component contained on a silica-alumina or a silica-alumina-containing carrier which contains 5 to 50% by weight of silica and which possesses the following properties: (1) a specific surface area of more than about 300 m 2 per gram; (2) a volume of pores having a diameter ranging from 0 to 600 Angstroms less than about 80% of the total volume of pores; (3) a volume of pores having a diameter ranging from 150 to 600 Angstroms more than about 30% of the volume of pores having a diameter ranging from 0 to 600 Angstroms; and (4) a bulk density less than about 0.5 grams per milliliter.
Claim 3
Dependent Claim
35 words
The process of claim 1 wherein the metal component of said catalyst is a metal, metal oxide or mixtures thereof, said metal selected from the group consisting of copper, chromium, vanadium, iron and mixtures thereof.
Claim 4
Dependent Claim
16 words
The process of claim 1 wherein said carrier contains from 10 to 25% by weight silica.
Claim 5
Dependent Claim
41 words
The process of claim 2 wherein the amount of ammonia mixed with said exhaust gas is at least about 0.7 times the stoichiometric amount of ammonia required for reducing the nitrogen oxides contained in said exhaust gas to nitrogen and water.
Claim 6
Dependent Claim
25 words
The process of claim 4 wherein said ammonia/exhaust gas contacting with said catalyst is conducted at a temperature varying from about 300° to 400° C.
Claim 7
Dependent Claim
15 words
The process of claim 5 wherein said metal component of said catalyst is copper oxide.
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) | 1983-04-22 | 1983-10-22 | 1984-04-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-04-22 | 1987-10-22 | 1988-04-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-04-22 | 1991-10-22 | 1992-04-22 | $7700.00 | Window Closed / Lapsed |