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U.S. Department of Energy
Office of Scientific and Technical Information

Continuous autorefrigerative dewaxing process and apparatus

Patent ·
OSTI ID:6864636
A continuous autorefrigerant solvent dewaxing process is disclosed wherein a waxy oil is prediluted with a nonautorefrigerative solvent, such as ketone, preferably a mixture of mek/mibk, and then passed, at a temperature above its cloud point, to the top of a chilling zone, which is an autorefrigerant chilling zone operating on a continuous basis, and comprises a vertical, multi-staged tower, operating at constant pressure. In this chilling zone, wax is precipitated from the oil to form a waxy slurry and the so-formed slurry is further chilled down to the wax filtration temperature by stagewise contact with liquid autorefrigerant preferably propylene, which is injected into a plurality of said stages and evaporated therein so as to cool the waxy slurry at an average rate of between about 0.1* to 20* F. Per minute with an average temperature drop across each stage of between about 2* and 20* F. Some of the propylene remains in the oil which serves to further dilute and reduce the viscosity of the slurry. The dewaxed oil-containing slurry may then be fed directly to wax filters without having to pass through scrapedsurface chillers and filter feed drum.
Assignee:
Exxon Research And Engineering Co
Patent Number(s):
US 4217203
OSTI ID:
6864636
Country of Publication:
United States
Language:
English