Abstract: An integrated hydrocarbon conversion process wherein two different heavy oil feed streams are thermally processed is disclosed. Preferably a vacuum gas oil is charged to a thermal cracking zone and a reduced crude fraction is charged to a visbreaking heater. The effluent of each thermal operation is separated into vapor and liquid fractions, with the vapor fractions being fed to a product fractionator. The liquid fractions each enter separate but interconnected subatmospheric pressure separation zones, one of which is a vacuum column. The bottoms of a product fractionator and distillate from the vacuum column are also charged to the thermal cracking zone.

Abstract: The amount of heat input required for the sequential fractionation of a crude oil in a crude column and a vacuum column is reduced by an improved heat exchange method wherein the desalted crude oil is flashed and the flash zone liquid is split into two streams. One of the streams is first heat exchanged against an atmospheric gas oil stream from the crude column and then against a first asphalt stream from the vacuum column. The other stream is first heat exchanged against a heavy vacuum gas oil stream from the vacuum column and then against a second asphalt stream from the vacuum column. The two streams are then recombined, heated and passed into the crude column.