摘要 |
Ultrafiltration may be effectively used to produce visbreaker feeds of improved quality which enable the visbreaker to be operated at higher severity with higher yields of distillable products. A heavy oil feed stream is separated by ultrafiltration or membrane separation into a permeate fraction and a retentate fraction by contacting the heavy oil feed with the first side of a porous membrane separation element in a membrane separation zone. The permeate fraction, comprised of materials which pass selectively through the porous membrane element, is retrieved and at least a portion of it is subjected to visbreaking with the improved liquid yield, especially of lighter distillate fractions. The retentate fraction can be retrieved from the first side of the porous membrane and can also be subjected to visbreaking.
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