| 摘要 |
A process for solvent dewaxing a waxy oil feed to produce a lubricating oil by contacting a warm waxy oil feed in counter-current with a cold oil/solvent filtrate stream through a selectively permeable membrane to transfer cold solvent through the membrane to the feed and simultaneously cool the feed, dilute it with solvent and separate solvent from the cold oil/solvent filtrate stream. The cooled, diluted feed stream is then further cooled to precipitate the wax to form an oil/solvent/wax mixture which is further diluted with cold solvent and filtered to remove wax. The cold oil/solvent filtrate stream is cycled to the selectively permeable membrane for the counter-current contact with the warm waxy oil feed and, after removal of a portion of the solvent over the membrane, is sent to an oil/solvent separation operation in which the solvent is removed from the dewaxed oil. |
