US4080425A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Elimination of nitrogen oxides from exhaust gases with nitriles
Assignee: Asahi Kasei Corp
•
Filing: 1976-05-26
•
Granted: 1978-03-21
•
Expires: 1996-05-26
Abstract
Abstract An exhaust gas containing nitrogen oxides is efficiently purified without the necessary use of catalysts by contacting the exhaust gas with a nitrile compound at high temperature in the presence of oxygen, whereby the nitrogen oxides and the nitrile compound are selectively decomposed into harmless materials.
Inventors
- 👤 Tetsuo Tanaka
- 👤 Tadatsugu Yamamoto
- 👤 Yasuo Takahashi
- 👤 Hideaki Obana
- 👤 Kunio Watanabe
- 👤 Kunihiko Wada
- 👤 Kunihiko Yamashita
- 👤 Kusuo Ohki
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 15:30
CPC Classifications
B; B01; B01D; B01D53/00; B01D53/34; B01D53/46; B01D53/54; B01D53/56
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
64 words
A method of removing nitrogen oxides from an exhaust gas containing them which comprises contacting the exhaust gas with a nitrile compound in the presence of oxygen at a temperature of about 500° to about 1,000° C and a residence time of more than about 0.1 second without using a solid catalyst to decompose the nitrogen oxides and the nitrile compound into harmless components.
Claim 2
Independent Claim
64 words
A method of removing nitrogen oxides from an exhaust gas containing them which comprises contacting the exhaust gas with a nitrile compound in the presence of oxygen at a temperature of about 500° to about 1,000° C and a residence time of more than about 0.1 second without using a solid catalyst to decompose the nitrogen oxides and the nitrile compound into harmless components.
Claim 3
Dependent Claim
20 words
The method as claimed in claim 1, wherein said nitrile compound is a hydrocarbon having at least one CN group.
Claim 4
Dependent Claim
27 words
The method as claimed in claim 2, wherein said compound is a saturated or unsaturated aliphatic nitrile, a saturated or unsaturated aliphatic polynitrile, or an aromatic nitrile.
Claim 5
Dependent Claim
13 words
The method as claimed in claim 1, wherein said nitrile compound is acetonitrile.
Claim 6
Dependent Claim
23 words
The method as claimed in claim 1, wherein the molar ratio of the nitrile compound to nitrogen oxide is greater than about 0.5.
Claim 7
Dependent Claim
20 words
The method as claimed in claim 1, wherein the concentration of oxygen in the reaction system is greater than 0.3%.
Claim 8
Dependent Claim
19 words
The method as claimed in claim 1, wherein the residence time in the reaction system is above 0.5 second.
Claim 9
Dependent Claim
16 words
The method as claimed in claim 1, wherein said exhaust gas is a boiler exhaust gas.
Claim 10
Dependent Claim
21 words
The method as claimed in claim 1, wherein said exhaust gas is an exhaust gas from a nitric acid manufacturing factory.
Claim 11
Dependent Claim
21 words
The method as claimed in claim 1, wherein said exhaust gas contains hydrocarbons and oxygen containing hydrocarbons together with nitrogen oxide.
Claim 12
Dependent Claim
19 words
The method as claimed in claim 1, wherein said exhaust gas contains a nitrile compound together with nitrogen oxide.
Claim 13
Dependent Claim
29 words
The method as claimed in claim 1, wherein the exhaust gas is an exhaust gas containing the nitrile compound having been pretreated by being partially burned prior to processing.
Claim 14
Dependent Claim
35 words
The method as claimed in claim 12, wherein said burning of the exhaust gas is performed by dividing the exhaust gas into at least two streams and burning the divided streams using a combustion improver.
Claim 15
Dependent Claim
39 words
The method as claimed in claim 12, wherein said burning pretreatment of the exhaust gas is performed by dividing a flow of an exhaust gas into at least two streams and contacting one stream with a catalyst while heating.
Claim 16
Dependent Claim
35 words
The method as claimed in claim 14, wherein said catalyst is a noble metal catalyst comprising platinum or a catalyst composed of at least one oxide of nickel, chromium, cobalt, iron, vanadium, copper, or silver.
Claim 17
Dependent Claim
14 words
The method as claimed in claim 14, wherein said catalyst is a platinum-alumina catalyst.
Claim 18
Dependent Claim
34 words
The method as claimed in claim 3, wherein said nitrile compound is selected from the group consisting of acetonitrile, propionitrile, butyronitrile, acrylonitrile, methacrylonitrile, crotononitrile, malonitrile, succinonitrile, adiponitrile, fumaronitrile, maleonitrile, benzoitrile, tolunitrile or benzyl cyanide.
References Cited (Backward Citations)
GB276347A
Cited
GB962613A
Cited
US3599427A
Cited
US3846981A
Cited
US3867507A
Cited
US3900554A
Cited
US3988423A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1981-03-20 | 1981-09-19 | 1982-03-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-03-20 | 1985-09-19 | 1986-03-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-03-20 | 1989-09-19 | 1990-03-21 | $7700.00 | Window Closed / Lapsed |