fig2 represents the preferred embodiment of the invention similar numbers represent similar features as illustrated the procedure of fig2 employs the accumulator or accumulation techniques of my aforementioned patent although this is not critical accordingly a naphtha feed enters column 1 through line 2 and is fractionated in a manner known to those skilled in the art the overhead vapor fraction in line 3 at a temperature of about 380 u00b0 f hotter than for fig1 because of staged condensing is condensed in condensation zone 20 preferably in a series of condensation stages for example the condensers may comprise shell and tube heat exchangers the proportion condensed at this point will vary depending on the requirements of the operation and may be determined by those skilled in the art preferably the overhead fraction is cooled to about 340 u00b0 f thus condensing an amount of liquid sufficient to provide reflux to column 1 from the last stage a liquid vapor stream is forwarded via line 21 to separation zone 22 where the vapor and liquid are separated separation zone 22 may comprise merely a centrifugal type entrainment separator a typical vapor liquid separator pot or may be built into the condensing zone liquid is removed from zone 22 via line 23 and is forwarded to accumulator 11 accumulator 11 may vary considerably in external design but follows generally the requirements described in u s pat no 4 235 706 more particularly accumulator 11 is provided with a barrier 24 which divides the accumulator into two separate liquid containing sections there being only limited liquid communication between the two sections as will be illustrated later at the same time barrier 24 is constructed.