Page 224 - Distillation theory

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198 Distillation Trajectories in Infinite Complex Columns and Complexes

It is just lately that Petlyuk columns came into industrial use. BASF AG was
the first firm since 1985 to use them in industry (25 industrial columns with a
dividing wall) (Becker et al., 2001). Firm MW Kellog Limited, in collaboration
with BP, applied a column with a dividing wall in 1998, at the petroleum refinery
in Coriton (Great Britain) for the separation of benzines. This column was mod-
ernized from that with side withdrawal of aircraft gasoline, which increased its
manufacture by more than 50%. In 1998, the firms Sumitomo Heavy Industries
Co. and Kyowa Yuka installed a column with a dividing wall for obtaining various
chemical products of high purity (right up to 99.999%) (Parkinson et al., 1999)
and has been involved in designing at least six columns (Parkinson, 2000).
The firm Krupp Uhde (Ennenbach, Kolbe, & Ranke, 2000) started to use
columns with a dividing wall in order to reduce from benzine fraction C 6 with big
content of benzene (50%) for obtaining of benzine with small content of benzene
and for posterior obtaining of pure benzene. Fraction C 5 is the top product, and
fraction C 7+ is the bottom product. Another sphere of application is recovery of
benzene-toluene fraction from reformate or from benzine pyrolisis product. The
economy of energy expenditures compared with regular sequence of two column
constitutes 35% and economy of capital costs constitutes 20%. New installation
was put into operation in the year 2000, and the first reconstruction of a simple
column into a column with a dividing wall was realized in 1999 (replacement of
the middle part of the column required only 10 days). Linde AG constructed
the largest column with a dividing wall for Sasol, estimated to be 107 m tall and
5 m in diameter (Parkinson, 2000). UOP designed columns with a dividing wall
for new linear alkyl benzene complex. One its application is the prefractionation
of kerosene (top product being C 10 and lighter; side(main) product, C 11 ÷ C 13 ;
bottom product, C 14 and heavier). Column with a dividing wall yields an energy
savings of 30% and a capital savings of 28%. UOP also applied a column with a
dividing wall for an untypical separation: it removes C 7+ aromatics from a desired
C 7+ olefin/paraffin mixture. In this case, the column with a dividing wall has three
product flows, two feedings, and two external reflux streams. Column with a di-
viding wall yields an energy savings of 50% and a capital savings of 45% (Schultz
et al., 2002).
Therefore, wide introduction of columns with a dividing wall into fine chemical
industry, into oil-refining and petrochemistry, is occurring.
Petlyuk columns were also introduced (Petlyuk et al., 1965) for separation of
mixtures with more than three products (Fig. 6.13a). Similar sequences of consec-
utive separation were examined in the work (Sargent & Gaminibandara, 1976).
Other configurations of these columns with satellite shells of the columns were
introduced in the work (Agrawal, 1996). Configurations of columns maintaining
one-directed movement of vapor flow (more operable) for n = 4 (Fig. 6.13b) and
for n = 5 were developed in the work (Agrawal, 1999). Columns with separa-
tion in one shell and with several vertical partitions (Fig. 6.13c) were introduced
for four- and five-component mixtures (Kaibel, 1987; Christiansen, Scogestad, &
Lien, 1997a; Agrawal, 1999).