Patent ID: 7837879

Claim:
A process for improving the distillable liquid yield from a visbreaking operation, comprising: (i) contacting a heavy hydrocarbon feed stream having an initial boiling point of at least 350° C. and a 5% point above 425° C. and consisting of a vacuum resid or a vacuum resid with a portion of the retentate fraction from step (iii) with a first side of a porous membrane element of metal, ceramic or glass or a combination thereof having a porosity of 2 to 500 kiloDaltons in a membrane separation zone at a temperature of at least 200 to 350° C. and with a transmembrane pressure of at least 2500 kPa, to separate the heavy oil feed stream into retentate fraction which remains on the first side of the porous membrane element and a permeate fraction comprised of materials which pass selectively through the porous membrane element from the first side of the porous membrane to a second side of the porous membrane element, (ii) retrieving the permeate product stream from the second side of the porous membrane element, (iii) retrieving a retentate fraction from the first side of the porous membrane element; (iv) subjecting at least a portion of the retrieved permeate fraction to visbreaking, and (v) subjecting the retrieved retentate stream to visbreaking separately from the retrieved permeate fraction at a severity from 0.7 to 1.2 times as great as could be applied to the heavy hydrocarbon feed at comparable coke make or comparable hot filtration sediment generation.