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:
Jan. 13, 1976
Filed:
Sep. 11, 1974
Robert William Lewis, Houston, TX (US);
Lawrence Walker Maas, Pasadena, TX (US);
Shell Oil Company, Houston, TX (US);
Abstract
A method for producing uninhibited transformer oil is disclosed which includes isolating a petroleum distillate that is primarily naphthenic and aromatic in character, boiling above 400.degree.F, having a viscosity between 50 and 100 SSU at 100.degree.F, and containing sulfur compounds; contacting the distillate with a solvent selective for aromatic hydrocarbons under conditions to produce a raffinate phase containing 15-30%v aromatic hydrocarbons; hydrotreating the raffinate phase to reduce the nitrogen content to at most 25 PPM, to maintain the sulfur content greater than 0.08%w, and to maintain the aromatic hydrocarbon content greater than 15%v. The product is an uninhibited transformer oil, and it can be further improved by regenerative clay treatment and by the addition of certain aromatic hydrocarbon compounds containing two or more six carbon membered fused or unfused rings, at least one of which is a benzene ring.