| 摘要 |
A process for solvent dewaxing a waxy oil feed to obtain petroleum oil lubricating stock comprising the steps of counter-currently contacting a warm waxy oil feed (101) with a selective permeable membrane to selectively transfer cold solvent from a cold oil/solvent filtrate stream (110) through the membrane to the warm waxy oil feed. The transfer of the cold solvent to the warm waxy oil feed simultaneously cools the warm waxy oil feed, dilutes the warm waxy oil feed with solvent and separates the solvent from the cold oil/solvent filtrate stream. The waxy oil feed after cooling and dilution (102) is further cooled by indirect heat exchange first with cold filtrate (109), then with refrigerant, to crystallize and precipitate the wax in the oil feed to form an oil/solvent/wax mixture, the oil/solvent/wax mixture is further diluted with cold solvent (104) to adjust the viscosity of the mixture and the mixture is fed to a filter (11) which filters and removes the wax from the cold oil/solvent/wax mixture. A cold wax cake (112) is recovered and a cold oil/solvent filtrate stream (108) is recovered.
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