Toa Nenryo Kogyo Kabushiki Kaisha

Fumio Ohashi

Kikuji Komine

Takashi Onodera

Tsutomo Naito

Tsutomu Naito

In a solvent dewaxing process wherein a waxy hydrocarbon oil is mixed with a dewaxing aid and dewaxing solvent and chilled to form a slurry comprising solid particles of wax and a mixture of dewaxed oil and solvent, the improvement which comprises using a polymeric dewaxing aid comprising a condensation product of naphthalene and chlorinated wax having an average molecular weight ranging from about 20,000 to 500,000 and a molecular weight distribution exceeding the range of from about 10,000 to 1,000,000.

Solvent dewaxing waxy hydrocarbon oils using dewaxing aid

Dewaxing aid used in a solvent dewaxing process is recovered in wax bottoms from slack wax by vacuum distilling the slack wax to about 5-10 wt. % bottoms at a temperature no greater than about 320.degree. C. The dewaxing aid-containing wax bottoms is recycled back into the dewaxing process by adding same to the wax-containing oil feed in an amount ranging from about 0.5-5 wt. %. This has been found to be particularly advantageous when the dewaxing aid is an .alpha.-olefin copolymer, a chlorinated paraffin/naphthalene condensation product and mixture thereof because of their thermal stability.

Recovery and recycle of dewaxing aid

An improved dewaxing aid for solvent dewaxing process comprising a mixture of (A) an .alpha.-olefin polymer having an average molecular weight of from about 10,000 to 1,000,000 and a wide molecular weight distribution exceeding the range of from about 10,000 to 1,000,000 but falling within the range of from about 2,000 to 3,000,000 and (B) an olefin-vinyl acetate copolymer having a vinyl acetate content of from about 15 to 40 wt.% and an average molecular weight of from about 50,000 to 1,000,000. The .alpha.-olefin polymer having a high molecular weight and wide molecular weight distribution, when combined with the olefin-vinyl acetate copolymer, synergistically improves the efficiency of wax separation.

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Ohi, Japan

Fumio Ohashi