A process and system for separating a fuel stream containing a low
concentration of sulfur compounds from a primary fuel stream is
disclosed. The process includes isolating a stage-one permeate stream and
a stage-one retentate stream from the primary fuel stream, evaporating
the stage-one permeate stream at a vacuum, and isolating a stage-two
permeate stream and a stage-two retentate stream from the stage-one
permeate stream. The stage-two retentate stream is a fuel stream
containing low concentrations of sulfur compounds. The system includes a
fuel supply, a stage-one separator for separating a fuel stream into a
stage-one permeate stream and a stage-one retentate stream, a stage-two
separator, a first supply line connecting a portion of the fuel supply to
the stage-one separator, and a second supply line connecting the
stage-one separator permeate stream to the stage-two separator. The
stage-two separator isolates the stage-one separator permeate stream into
a stage-two permeate stream and a stage-two retentate stream.