US3615166A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Catalysts for purification of waste gases containing oxides of nitrogen
Assignee: Engelhard Minerals and Chemicals Corp
•
Filing: 1969-06-16
•
Granted: 1971-10-26
•
Expires: 1989-06-16
Abstract
Abstract Improved catalysts for use in the purification of waste gases containing oxides of nitrogen comprise high surface area thoria or zirconia as a support for a catalytic deposit. The catalysts exhibit exceptionally high stability in the reaction environment.
Inventors
- 👤 Saul G Hindin
- 👤 Joseph C Dettling
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 17:39
CPC Classifications
B; B01; B01J; B01J23/00; B01J23/38; B01J23/54; B01J23/56; B01J23/63; B01D; B01D53/00; B01D53/34; B01D53/74; B01D53/86; B01D53/8621; B01D53/8625; B01D53/8628; B01J23/40; B01J23/44; B01J37/00; B01J37/02; B01J37/0215; B01J37/0217; B01J37/0221; B01J37/024; B01J2235/00; B01J2235/15; B01J35/00; B01J35/30
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
15 words
A catalyst of claim 1 wherein the coating is thoria and the core is alumina.
Claim 2
Dependent Claim
15 words
A catalyst of claim 1 wherein the coating is zirconia and the core is alumina.
Claim 3
Dependent Claim
32 words
A catalyst of claim 1 wherein the thoria or zirconia coating has a surface area of about at least 50 m2/g after calcination at a temperature of 1,000* C. for 4 hours.
Claim 4
Dependent Claim
66 words
A process for the purification of noxious gases containing oxides of nitrogen in order to produce a gas which can be dIscharged safely into the atmosphere which comprises adding to such gases a reducing fuel and bringing the resultant gaseous mixture in contact with a catalyst of claim 1 at a temperature of about 100 to 600* C. and pressure of about atmospheric to 200 p.s.i.g.
Claim 5
Dependent Claim
29 words
A process of claim 5 wherein the reducing fuel comprises methane and the gaseous mixture is contacted with the catalyst at a temperature of about 300* to 600* C.
Claim 6
Dependent Claim
17 words
A process of claim 6 wherein the oxides of nitrogen are reduced to less than 100 p.p.m.
Claim 7
Dependent Claim
109 words
In a method of preparing a catalyst of claim 1 the steps comprising: a. dispersing the inert refractory core material as particles of colloidal size in a water-miscible liquid, b. mixing an aqueous solution of a water-soluble salt of thorium or zirconium with the colloidal dispersion of the core particles, said water-soluble salt and core material being present in a proportion of an equivalent of 10-50 percent by weight thoria or zirconia and the balance core material, c. adding an alkaline reagent to precipitate thoria or zirconia on the core material and d. calcining the coated core material at a temperature in the range of 500* to 1,000* C.
Claim 8
Dependent Claim
11 words
A method of claim 8 wherein the alkaline reagent is NH4OH.
Claim 9
Dependent Claim
17 words
A method of claim 9 wherein the coated core is calcined at 1,000* C. for 4 hours.
Claim 10
Dependent Claim
11 words
A method of claim 8 wherein the core material is alumina.
Claim 11
Dependent Claim
23 words
A catalytic structure consisting of a ceramic honeycomb support and a catalyst deposited thereon wherein said catalyst is the catalyst of claim 1.
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) | 1974-10-25 | 1975-04-26 | 1975-10-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-10-25 | 1979-04-26 | 1979-10-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-10-25 | 1983-04-26 | 1983-10-26 | $7700.00 | Window Closed / Lapsed |