Claims
- 1. A method for removing nitrogen oxides from exhaust gas containing oxygen and moisture, comprising the step of
- bringing the exhaust gas into contact with a hydrogenated zeolite catalyst selected from the group consisting of hydrogenated synthetic zeolites, hydrogenated natural zeolites, hydrogenated synthetic zeolites impregnated with one or more metals selected from the group consisting of copper, zinc, vanadium, chromium, manganese, iron, cobalt, nickel, rhodium, palladium, platinum and molybdenum, and hydrogenated natural zeolites impregnated with one or more metals selected from the group consisting of copper, zinc, vanadium, chromium, manganese, iron, cobalt, nickel, rhodium, palladium, platinum, and molybdenum, in the presence of organic compounds as a reducing agent selected from the group consisting of hydrocarbons, alcohols, ketones, or ether, at a temperature sufficient to cause reaction between said hydrogenated zeolite catalyst and said nitrogen oxides.
- 2. A method for removing nitrogen oxides from exhaust gas as claimed in claim 1, wherein the zeolite catalyst is a zeolite having a silica/alumina ratio of 5 or above.
- 3. A method for removing nitrogen oxides from exhaust gas as claimed in claim 1 or claim 2, wherein the hydrogenated zeolite catalyst is any one of zeolite of Y type, zeolite of L type, zeolite of offretite-erionite mixed crystal type, zeolite of ferrierite type, zeolite of mordenite type, zeolite of clinoptilolite type, and zeolite of ZSM-5 type.
Priority Claims (1)
Number |
Date |
Country |
Kind |
1-319228 |
Dec 1989 |
JPX |
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Parent Case Info
This is a continuation of application Ser. No. 07/504,156 filed Apr. 3, 1990, now abandoned.
US Referenced Citations (6)
Foreign Referenced Citations (7)
Number |
Date |
Country |
3642018 |
Jun 1987 |
DEX |
3830045 |
Mar 1990 |
DEX |
53-39200 |
Oct 1978 |
JPX |
54-8351 |
Apr 1979 |
JPX |
61-36977 |
Aug 1986 |
JPX |
1474119 |
May 1977 |
GBX |
1488017 |
Oct 1977 |
GBX |
Continuations (1)
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Number |
Date |
Country |
Parent |
504156 |
Apr 1990 |
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