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. 01, 1990
Filed:
Aug. 20, 1987
Fritz A Smith, New Hope, PA (US);
Mobil Oil Corporation, New York, NY (US);
Abstract
A lubricant dewaxing process which is useful with difficult feeds, especially highly waxy feeds having paraffin contents in excess of 25 weight percent of feeds with high nitrogen levels, employs two-step dewaxing in which the first stage is carried out under relatively mild conditions to obtain extended catalyst cycle life between successive reactivations with a constant temperature for the duration of each dewaxing cycle. The second stage dewaxing is carried out under conditions which maintain the target pour point for the product with a progressively increasing temperature during each dewaxing cycle. More than one preliminary dewaxing stage may be provided in order to reduce severity in each stage with mild conditions and constant temperature being maintained in the preliminary steps. Using this process, extended catalyst cycle lives may be obtained with difficult feeds.