The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Aug. 19, 1997
Filed:
Nov. 14, 1994
Kiyohide Yoshida, Kumagaya, JP;
Gyo Muramatsu, Kumagaya, JP;
Akira Abe, Kumagaya, JP;
Naoko Irite, Kumagaya, JP;
Kabushiki Kaisha Riken, Tokyo, JP;
Abstract
Nitrogen oxides are efficiently removed from an exhaust gas containing nitrogen oxides and an excess amount of oxygen, by (i) disposing an exhaust gas cleaner in a flow path of the exhaust gas, the exhaust gas cleaner comprising a first catalyst comprising 0.2-15 weight % (on a metal basis) of at least one silver salt selected from the group consisting of silver halides, silver sulfate and silver phosphate supported on a porous inorganic oxide on an inlet side and a second catalyst comprising (a) 0.2-15 weight % (on a metal basis) of at least one silver salt selected from the group consisting of silver halides, silver sulfate and silver phosphate and (b) up to 2 weight % (on a metal basis) of copper or copper oxide supported on a porous inorganic oxide on an outlet side; (ii) introducing at least one reducing agent selected from hydrocarbons and oxygen-containing organic compounds into the exhaust gas on an upstream side of the exhaust gas cleaner; and (iii) bringing the exhaust gas into contact with the exhaust gas cleaner at a temperature of 200.degree.-600.degree. C.