| 摘要 |
<p>Used oil, such as automotive crankcase oil drainings from internal combustion engines, are pretreated by heating to above about 400-800.degree.F, and preferably between 600-750.degree.F, while an essentially liquid phase system is maintained at a pressure of between 500-3500 p.s.i.g., preferably between 2000-3500 p.s.i.g., for between 15-60 minutes, the contact time being even shorter at higher temperatures. A sludge which contains contaminants, such as insoluble degradation products, metallic compounds, and water, is separated preferably by centrifugation, leaving a substantially ashless oil ready for additional refinement to a high quality lubricating oil, or it may be used, per se, as a fuel oil.</p> |
