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:
May. 03, 1994
Filed:
Dec. 28, 1992
Andrew P Voss, Cerritos, CA (US);
William Murray, Orange, CA (US);
Ruthjean Stager, Fullerton, CA (US);
Atlantic Richfield Company, Los Angeles, CA (US);
Abstract
A method of treating spent selective catalytic reduction (SCR) catalyst is provided, which method comprises contacting the spent catalyst with a solution comprising a SCR catalyst metal salt, preferably a vanadium salt, and heating the catalyst contacted with the metal salt solution at a calcination temperature in the presence of oxygen. Preferably, after treatment with the metal salt solution, the catalyst is dried with air for at least about 10 seconds and heated to a temperature in the range of about 130.degree. F. to about 170.degree. F. for a period of about 30 minutes to about 90 minutes before heating to the calcination temperature. In addition, a method is provided for restoring the catalytic activity of a SCR catalyst, contaminated with platinum, to enhance catalytic reduction of oxides of nitrogen to nitrogen by the SCR catalyst, said method comprising (a) contacting the spent catalyst with a metal salt containing solution; (b) then heating the catalyst in the presence of oxygen to a calcination temperature at which the metal salt is decomposed to form an oxide of the metal and the metal oxide is bonded to the catalyst support, to form a calcined catalyst; and, (c.) contacting the calcined catalyst with a SCR flue gas stream at a temperature in the range of about 450.degree. F. to about 750.degree. F. Calcination temperatures as low as 250.degree. F. are effective to restore SCR catalyst activity.