| 摘要 |
<PICT:0447415/III/1> Hydrocarbon oils are de-waxed by diluting the oil with a heavy solvent whereby the oil solution is heavier than the wax and separating the wax in a centrifuge provided with a perforate wall in which a body of oil solution is maintained between the wall and the separated wax layer and when the body of wax is built up, removing the oil layer whereby the wax moves up to the wall. The wax is then washed with solvent. The wax layer is maintained in the desired position by controlling the inflowing wax-containing oil. Both crystalline and amorphous waxes are removed. The solvent preferably consists of a chlorinated hydrocarbon diluted with 25 per cent or more of a hydrocarbon diluent such as benzene or naphtha. Ethylene, methylene or propylene dichloride; dichlorethylene or trichlorethylene are specified. The oil is mixed with the solvent at 100 DEG F., and then cooled to -20 DEG F. A suitable centrifuge consists of a bowl 10 mounted on a shaft 11. The bowl is provided with a perforated wall or screen 14 and a spacing member 15 consisting of a coarse wire screen. A disc 16 extends radially inwards to form a liquid compartment 18. Liquid flows into the bowl through a nozzle 23 and channels 21, 22 at a rate controlled by wings 25. An adjustable skimming nozzle 28 when in position B removes liquid passing through the filter screen, and a scraper 31 and discharge shoot 32 removes the separated and washed wax. U.S.A. Specifications 1,351,265 and 1,761,593 are referred to.
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